Atomic bombings of Hiroshima and Nagasaki

Background.

Pacific War.

In 1945, the Pacific War between the Empire of Japan and the Allies entered its fourth year. Most Japanese military units fought fiercely, ensuring that the Allied victory would come at an enormous cost. The 1.25 million battle casualties incurred in total by the United States in World War II included both military personnel killed in action and wounded in action. Nearly one million of the casualties occurred during the last year of the war, from June 1944 to June 1945. In December 1944, American battle casualties hit an all-time monthly high of 88,000 as a result of the German Ardennes Offensive. America's reserves of manpower were running out. Deferments for groups such as agricultural workers were tightened, and there was consideration of drafting women. At the same time, the public was becoming war-weary, and demanding that long-serving servicemen be sent home.  In the Pacific, the Allies returned to the Philippines, recaptured Burma, and invaded Borneo. Offensives were undertaken to reduce the Japanese forces remaining in Bougainville, New Guinea and the Philippines. In

Preparations to invade Japan.

Even before the surrender of Nazi Germany on May 8, 1945, plans were underway for the largest operation of the Pacific War, Operation Downfall, the Allied invasion of Japan. The operation had two parts: Operation Olympic and Operation Coronet. Set to begin in October 1945, Olympic involved a series of landings by the U.S. Sixth Army intended to capture the southern third of the southernmost main Japanese island, Kyūshū. Operation Olympic was to be followed in March 1946 by Operation Coronet, the capture of the Kantō Plain, near Tokyo on the main Japanese

Air raids on Japan.

While the United States had developed plans for an air campaign against Japan prior to the Pacific War, the capture of Allied bases in the western Pacific in the first weeks of the conflict meant that this offensive did not begin until mid-1944 when the long-ranged Boeing B-29 Superfortress became ready for use in combat. Operation Matterhorn involved India-based B-29s staging through bases around Chengdu in China to make a series of raids on strategic targets in Japan. This effort failed to achieve the strategic objectives that its planners had intended, largely because of logistical problems, the bomber's mechanical difficulties, the vulnerability of Chinese staging bases, and the extreme range required to reach key Japanese cities.

Atomic bomb development.

The discovery of nuclear fission by German chemists Otto Hahn and Fritz Strassmann in 1938, and its theoretical explanation by Lise Meitner and Otto Frisch, made the development of an atomic bomb a theoretical possibility. Fears that a German atomic bomb project would develop atomic weapons first, especially among scientists who were refugees from Nazi Germany and other fascist countries, were expressed in the Einstein-Szilard letter. This prompted preliminary research in the United States in late 1939. Progress was slow until the arrival of the British MAUD Committee report in late 1941, which indicated that only 5 to 10 kilograms of isotopically enriched uranium-235 were needed for a bomb instead of tons of natural uranium

Preparations.

Organization and training.

The 509th Composite Group was constituted on December 9, 1944, and activated on December 17, 1944, at Wendover Army Air Field, Utah, commanded by Colonel Paul Tibbets. Tibbets was assigned to organize and command a combat group to develop the means of delivering an atomic weapon against targets in Germany and Japan. Because the flying squadrons of the group consisted of both bomber and transport aircraft, the group was designated as a "composite" rather than a "bombardment" unit. Working with the Manhattan Project at Los Alamos, Tibbets selected Wendover for his training base over Great Bend, Kansas, and Mountain Home, Idaho, because of its remoteness. Each bombardier completed at least 50 practice drops of inert or conventional explosive pumpkin bombs and Tibbets declared his group combat-ready. On April 5, 1945, the code name Operation Centerboard was assigned. The officer responsible for its allocation in the War Department's Operations Division was not cleared to know any details of it. The first bombing was later codenamed Operation Centerboard I, and the second, Operation Centerboard II.

Choice of targets.

In April 1945, Marshall asked Groves to nominate specific targets for bombing for final approval by himself and Stimson. Groves formed a Target Committee, chaired by himself, that included Farrell, Major John A. Derry, Colonel William P. Fisher, Joyce C. Stearns and David M. Dennison from the USAAF; and scientists John von Neumann, Robert R. Wilson and William Penney from the Manhattan Project. The Target Committee met in Washington on April 27; at Los Alamos on May 10, where it was able to talk to the scientists and technicians there; and

Proposed demonstration.

In early May 1945, the Interim Committee was created by Stimson at the urging of leaders of the Manhattan Project and with the approval of Truman to advise on matters pertaining to nuclear energy. During the meetings on May 31 and June 1, scientist Ernest Lawrence had suggested giving the Japanese a non-combat demonstration. Arthur Compton later recalled that: The possibility of a demonstration was raised again in the Franck Report issued by physicist James Franck on June 11 and the Scientific Advisory Panel rejected his report on June 16, saying that "we can propose no technical demonstration likely to bring an end to the war;

Leaflets.

For several months, the U.S. had warned civilians of potential air raids by dropping more than 63 million leaflets across Japan. Many Japanese cities suffered terrible damage from aerial bombings; some were as much as 97% destroyed. LeMay thought that leaflets would increase the psychological impact of bombing, and reduce the international stigma of area-bombing cities. Even with the warnings, Japanese opposition to the war remained ineffective. In general, the Japanese regarded the leaflet messages as truthful, with many Japanese choosing to leave major cities. The leaflets caused such concern that the government ordered the arrest of anyone caught in possession of a leaflet. Leaflet texts were prepared by recent Japanese prisoners of war because they were thought to be the best choice "to appeal to their compatriots".  In preparation for dropping an atomic bomb on Hiroshima, the Oppenheimer-led Scientific

Consultation with Britain and Canada.

In 1943, The United States and the United Kingdom signed the Quebec Agreement, which stipulated that nuclear weapons would not be used against another country without mutual consent. Stimson therefore had to obtain British permission. A meeting of the Combined Policy Committee, which included one Canadian representative, was held at the Pentagon on July 4, 1945. Field Marshal Sir Henry Maitland Wilson announced that the British government concurred with the use of nuclear weapons against Japan, which would

Potsdam Declaration.

The July 16 success of the Trinity Test in the New Mexico desert exceeded expectations. On July 26, Allied leaders issued the Potsdam Declaration, which outlined the terms of surrender for Japan. The declaration was presented as an ultimatum and stated that without a surrender, the Allies would attack Japan, resulting in "the inevitable and complete destruction of the Japanese armed forces and just as inevitably the utter devastation of the Japanese homeland". The atomic bomb was not mentioned in the communiqué.  On July 28, Japanese papers reported that the declaration had been rejected by the Japanese government. That afternoon, Prime Minister Suzuki Kantarō declared at a press conference that the

Bombs.

The Little Boy bomb, except for the uranium payload, was ready at the beginning of May 1945. There were two uranium-235 components, a hollow cylindrical projectile and a cylindrical target insert. The projectile was completed on June 15, and the target insert on July 24. The projectile and eight bomb pre-assemblies (partly assembled bombs without the powder charge and fissile components) left Hunters Point Naval Shipyard, California, on July 16 aboard the cruiser, and arrived on Tinian on July 26. The target insert followed by air on July 30, accompanied by Commander Francis Birch from Project Alberta. Responding to concerns expressed by the 509th

Hiroshima.

Hiroshima during World War II.

At the time of its bombing, Hiroshima was a city of industrial and military significance. A number of military units were located nearby, the most important of which was the headquarters of Field Marshal Shunroku Hata's Second General Army, which commanded the defense of all of southern Japan, and was located in Hiroshima Castle. Hata's command consisted of some 400,000 men, most of whom were on Kyushu where an Allied invasion was correctly anticipated. Also present in Hiroshima were the headquarters of the 59th Army, the 5th Division and the 224th Division, a recently formed mobile unit. The city was defended by five batteries of 7-cm and 8-cm (2.8 and 3.1 inch) anti-aircraft guns of the 3rd Anti-Aircraft Division, including units from the 121st and 122nd Anti-Aircraft Regiments and the 22nd and 45th Separate Anti-Aircraft Battalions. In total, an estimated 40,000 Japanese military personnel were stationed in the city.  Hiroshima was a supply and logistics base for the Japanese military. The city was a communications center, a key port for shipping, and an assembly area for

Bombing of Hiroshima.

Hiroshima was the primary target of the first atomic bombing mission on August 6, with Kokura and Nagasaki as alternative targets. The 393d Bombardment Squadron B-29 "Enola Gay", named after Tibbets' mother and piloted by Tibbets, took off from North Field, Tinian, about six hours' flight time from Japan. "Enola Gay" was accompanied by two other B-29s: "The Great Artiste", commanded by Major Charles Sweeney, which carried instrumentation, and a then-nameless aircraft later called "Necessary Evil", commanded by Captain George Marquardt, which served as the

Events on the ground.

People on the ground reported a —a brilliant flash of light—followed by a —a loud booming sound. Some 70,000–80,000 people, around 30% of the population of Hiroshima at the time, were killed by the blast and resultant firestorm, and another 70,000 were injured. It is estimated that as many as 20,000 Japanese military personnel were killed. U.S. surveys estimated that of the city were destroyed. Japanese officials determined that 69% of Hiroshima's buildings were destroyed and another 6–7% damaged.  Some of the reinforced concrete buildings in Hiroshima had been very strongly constructed because of the earthquake danger in Japan, and their framework did not collapse even though they were fairly close to the blast center. Since the bomb detonated in the air, the

Japanese realization of the bombing.

The Tokyo control operator of the Japan Broadcasting Corporation noticed that the Hiroshima station had gone off the air. He tried to re-establish his program by using another telephone line, but it too had failed. About 20 minutes later the Tokyo railroad telegraph center realized that the main line telegraph had stopped working just north of Hiroshima. From some small railway stops within of the city came unofficial and confused reports of a terrible explosion in Hiroshima. All these reports were transmitted to the headquarters of the Imperial Japanese Army General Staff.  Military bases repeatedly tried to call the Army Control Station in Hiroshima. The complete silence

Events of August 7–9.

After the Hiroshima bombing, Truman issued a statement announcing the use of the new weapon. He stated, "We may be grateful to Providence" that the German atomic bomb project had failed, and that the United States and its allies had "spent two billion dollars on the greatest scientific gamble in history—and won". Truman then warned Japan: "If they do not now accept our terms, they may expect a rain of ruin from the air, the like of which has never been seen on this earth. Behind this air attack will follow sea and land forces in such numbers and power as they have not yet seen and with the fighting skill of which they are already well aware." This was a widely broadcast speech picked up by Japanese news agencies. The 50,000-watt standard wave station on Saipan, the OWI radio station, broadcast a similar message to Japan every 15 minutes about Hiroshima, stating that more Japanese cities would face a similar fate in the absence of immediate acceptance of the terms of the Potsdam Declaration and emphatically urged civilians to evacuate major cities. Radio Japan, which continued to extoll victory for Japan by never surrendering, had informed the Japanese of the

Nagasaki.

Nagasaki during World War II.

The city of Nagasaki had been one of the largest seaports in southern Japan, and was of great wartime importance because of its wide-ranging industrial activity, including the production of ordnance, ships, military equipment, and other war materials. The four largest companies in the city were Mitsubishi Shipyards, Electrical Shipyards, Arms Plant, and Steel and Arms Works, which employed about 90% of the city's labor force, and accounted for 90% of the city's industry. Although an important industrial city, Nagasaki had been spared from firebombing because its geography made it difficult to locate at night with AN/APQ-13 radar.  Unlike the other target cities, Nagasaki had not been placed off limits to bombers by the Joint Chiefs of Staff's July 3 directive, and was bombed on a small scale five times. During one of these

Bombing of Nagasaki.

Responsibility for the timing of the second bombing was delegated to Tibbets. Scheduled for August 11 against Kokura, the raid was moved earlier by two days to avoid a five-day period of bad weather forecast to begin on August 10. Three bomb pre-assemblies had been transported to Tinian, labeled F-31, F-32, and F-33 on their exteriors. On August 8, a dress rehearsal was conducted off Tinian by Sweeney using "Bockscar" as the drop airplane. Assembly F-33 was expended testing the components and F-31 was designated for the August 9 mission.  At 03:49 on the morning of August 9, 1945, "Bockscar", flown by Sweeney's crew, carried Fat Man, with Kokura as the primary target and Nagasaki the secondary target. The mission plan for the second attack was nearly identical to that of the Hiroshima mission, with two B-29s flying an hour ahead as weather scouts and two additional B-29s in Sweeney's flight for instrumentation and photographic support of the mission. Sweeney took off with his weapon already armed but with the electrical safety plugs still engaged.  During pre-flight inspection of "Bockscar", the flight engineer notified Sweeney that an inoperative fuel transfer pump made it impossible to use of fuel

Events on the ground.

Although the bomb was more powerful than the one used on Hiroshima, its effects were confined by hillsides to the narrow Urakami Valley. Of 7,500 Japanese employees who worked inside the Mitsubishi Munitions plant, including "mobilized" students and regular workers, 6,200 were killed. Some 17,000–22,000 others who worked in other war plants and factories in the city died as well. Casualty estimates for immediate deaths vary widely, ranging from 22,000 to 75,000. At least 35,000–40,000 people were killed and 60,000 others injured. In the days and months following the explosion, more people died from their injuries. Because of the presence of undocumented foreign workers, and a number of military personnel in transit, there are great discrepancies in the estimates of total deaths by the end of 1945; a range of 39,000 to 80,000 can be found in various studies.  Unlike Hiroshima's military death toll, only 150 Japanese soldiers were killed instantly, including 36 from the 134th AAA Regiment of the 4th AAA Division. At least eight Allied prisoners of war (POWs) died from the bombing, and as many as thirteen may have died. The eight confirmed deaths included

Plans for more atomic attacks on Japan.

Groves expected to have another "Fat Man" atomic bomb ready for use on August 19, with three more in September and a further three in October; a second Little Boy bomb (using U-235) would not be available until December 1945. On August 10, he sent a memorandum to Marshall in which he wrote that "the next bomb... should be ready for delivery on the first suitable weather after 17 or 18 August." Marshall endorsed the memo with the hand-written comment, "It is not to be released over Japan without express authority from the President", something Truman had requested that day.

Surrender of Japan and subsequent occupation.

Until August 9, Japan's war council still insisted on its four conditions for surrender. The full cabinet met on 14:30 on August 9, and spent most of the day debating surrender. Anami conceded that victory was unlikely, but argued in favour of continuing the war nonetheless. The meeting ended at 17:30, with no decision having been reached. Suzuki went to the palace to report on the outcome of meeting, where he met with Kōichi Kido, the Lord Keeper of the Privy Seal of Japan. Kido informed him that the emperor had agreed to hold an imperial conference, and gave a strong indication that the emperor would consent to surrender on condition that "kokutai" be preserved. A second cabinet meeting was held at 18:00. Only four ministers supported Anami's position of adhering to the four conditions, but since cabinet decisions had to be unanimous, no decision was reached before it ended at 22:00.  Calling an imperial conference required

Reportage.

On August 10, 1945, the day after the Nagasaki bombing, Yōsuke Yamahata, correspondent Higashi, and artist Yamada arrived in the city with orders to record the destruction for maximum propaganda purposes, Yamahata took scores of photographs, and on August 21, they appeared in "Mainichi Shimbun", a popular Japanese newspaper. Leslie Nakashima filed the first personal account of the scene to appear in American newspapers. A version of his August 27 UPI article appeared in "The New York Times" on August 31.  Wilfred Burchett was the first western journalist to visit Hiroshima after the bombing, arriving alone by train from Tokyo on September 2. His Morse code dispatch, "The Atomic Plague", was printed by the "Daily Express" newspaper in London on September 5, 1945. Nakashima's and Burchett's reports were the first public reports to mention the effects of radiation and nuclear fallout—radiation burns and radiation poisoning. Burchett's reporting was unpopular with the U.S. military, who accused Burchett of being under the sway of Japanese propaganda, and suppressed a supporting story submitted by George Weller of the "Chicago Daily News". Laurence dismissed the reports on radiation sickness as Japanese efforts to undermine American morale, ignoring his own account published one week earlier.  A member of the U.S. Strategic Bombing Survey, Lieutenant Daniel McGovern, used a film crew to document the effects of the bombings in early 1946. The film crew shot of film, resulting in a three-hour documentary titled "The Effects of the Atomic Bombs Against Hiroshima and Nagasaki". The documentary included images from hospitals showing the human effects of the bomb; it showed burned-out buildings and cars, and rows of skulls and bones on the ground. It was classified "secret" for the next 22 years. Motion picture company Nippon Eigasha started sending cameramen to Nagasaki and Hiroshima in September 1945. On October 24, 1945, a U.S. military policeman stopped a Nippon Eigasha cameraman from continuing to

Post-attack casualties.

An estimated 90,000 to 140,000 people in Hiroshima (up to 39% of the population) and 60,000 to 80,000 people in Nagasaki (up to 32% of the population) died in 1945, though the number which died immediately as a result of exposure to the blast, heat, or due to radiation, is unknown. One Atomic Bomb Casualty Commission report discusses 6,882 people examined in Hiroshima, and 6,621 people examined in Nagasaki, who were largely within 2000 meters from the hypocenter, who suffered injuries from the blast and heat but died from complications frequently compounded by acute radiation syndrome (ARS), all within about 20–30 days. The most well known of these was Midori Naka, some 650 meters from the hypocenter at Hiroshima, who would travel to Tokyo and then with her death on August 24, 1945 was to be the first death officially certified as a result of radiation poisoning, or as it was referred to by many, "Atomic bomb disease". It was unappreciated at the time but the average radiation dose that will kill approximately 50% of adults, the LD50, was approximately halved, that is, smaller doses were made more lethal, when the individual experienced concurrent blast or burn polytraumatic injuries. Conventional skin injuries that cover a large area frequently result in bacterial infection; the risk of sepsis and death is increased when a usually non-lethal radiation dose moderately suppresses the white blood cell count.  In the spring of 1948, the Atomic Bomb Casualty Commission (ABCC) was established in accordance with a presidential directive from Truman to the National Academy of Sciences–National Research Council to conduct investigations of the late effects of radiation among the survivors in Hiroshima and Nagasaki. In 1956, the ABCC published "The Effect of Exposure to the Atomic Bombs on Pregnancy Termination in Hiroshima and Nagasaki". The ABCC became the Radiation Effects Research Foundation (RERF), on April 1, 1975. A binational organization run by both the United States and Japan, the RERF is still in operation today.

Cancer increases.

Cancers do not immediately emerge after exposure to radiation; instead, radiation-induced cancer has a minimum latency period of some 5+ years and Leukemia some 2+ which peaks around 6–8 years later. Dr Jarrett Foley published the first major reports on the significant increased incidence of the latter among survivors. Almost all cases of leukemia over the following 50 years were in people exposed to more than 1Gy. In a strictly dependent manner dependent on their distance from the hypocenter, in the 1987

Birth defect investigations.

While during the preimplantation period, that is 1–10 days following conception, interuterine radiation exposure of "at least 0.2 Gy" can cause complications of implantation and death of the human embryo. The number of miscarriages caused by the radiation from the bombings, during this radiosensitive period, is not known.  One of the early studies conducted by the ABCC was on the outcome of pregnancies occurring in Hiroshima and Nagasaki, and in a control city, Kure, located south of Hiroshima, to discern the conditions and outcomes related to radiation exposure. James V. Neel led the study which found that the overall number of birth defects was not significantly higher among the children of survivors who were pregnant at the time of the bombings. He also studied the longevity of the children who survived the bombings of Hiroshima and Nagasaki, reporting that between 90 and 95

Investigations into brain development.

Despite the small sample size of 1,600 to 1,800 persons who came forth as prenatally exposed at the time of the bombings, that were both within a close proximity to the two hypocenters, to survive the "in utero" absorption of a substantial dose of radiation and then the malnourished post-attack environment, data from this cohort does support the increased risk of severe mental retardation (SMR), that was observed in some 30 individuals, with SMR being a common outcome of the aforementioned microencephaly. While a lack of statistical data, with just 30 individuals out of 1,800, prevents

"Hibakusha".

The survivors of the bombings are called, a Japanese word that literally translates to "explosion-affected people". The Japanese government has recognized about 650,000 people as "hibakusha"., 145,844 were still alive, mostly in Japan. The government of Japan recognizes about 1% of these as having illnesses caused by radiation. The memorials in Hiroshima and Nagasaki contain lists of the names of the "hibakusha" who are known to have died since the bombings. Updated annually on the anniversaries of the bombings,, the memorials record the names of more than 500,000 "hibakusha"; 319,186 in Hiroshima and 182,601 in Nagasaki.  If they discuss their background, "Hibakusha" and their children were (and still are) victims of fear based discrimination and exclusion when it comes to prospects of marriage or work due to public ignorance about the consequences of radiation sickness or that the low doses that the majority received were less than a routine diagnostic x-ray, much of the public however persist with the belief that the Hibakusha carry some hereditary or even contagious disease. This is despite the fact that no statistically demonstrable increase of birth defects/congenital malformations was found among the "later conceived" children born to survivors of the nuclear weapons used at Hiroshima and Nagasaki, or indeed has been found in the later conceived children of cancer survivors who had previously received radiotherapy. The surviving women of Hiroshima and Nagasaki, that could conceive, who were exposed to substantial amounts of radiation, went on and had children with no higher incidence of abnormalities/birth defects than the rate which is observed in the Japanese average. A study of the long-term psychological effects of the bombings on the survivors found that even 17–20 years after the bombings had occurred survivors showed a higher prevalence of anxiety and somatization symptoms.

Double survivors.

Perhaps as many as 200 people from Hiroshima sought refuge in Nagasaki. The 2006 documentary "Twice Survived: The Doubly Atomic Bombed of Hiroshima and Nagasaki" documented 165 "nijū hibakusha (lit. double explosion-affected people)", nine of whom claimed to be in the blast zone in both cities. On March 24, 2009, the Japanese government officially recognized Tsutomu Yamaguchi as a double

Korean survivors.

During the war, Japan brought as many as 670,000 Korean conscripts to Japan to work as forced labor. About 5,000–8,000 Koreans were killed in Hiroshima and another 1,500–2,000 died in Nagasaki.

Memorials.

Hiroshima.

Hiroshima was subsequently struck by Typhoon Ida on September 17, 1945. More than half the bridges were destroyed, and the roads and railroads were damaged, further devastating the city. The population increased from 83,000 soon after the bombing to 146,000 in February 1946. The city was rebuilt after the war, with help from the national government through the Hiroshima

Nagasaki.

Nagasaki was also rebuilt after the war, but was dramatically changed in the process. The pace of reconstruction was initially slow, and the first simple emergency dwellings were not provided until 1946. The focus on redevelopment was the replacement of war industries with foreign trade, shipbuilding and fishing. This was

Debate over bombings.

The role of the bombings in Japan's surrender, and the ethical, legal, and military controversies surrounding the United States' justification for them have been the subject of scholarly and popular debate. On one hand, it has been argued that the bombings caused the Japanese surrender, thereby preventing casualties that an invasion of Japan would have involved. Stimson talked of saving one million casualties. The naval blockade might have starved the Japanese into submission without an invasion, but this would also have resulted in many more Japanese deaths.  Japanese historian

Legacy.

Like the way it began, the manner in which World War II ended cast a long shadow over international relations for decades to come. By June 30, 1946, there were components for only nine atomic bombs in the US arsenal, all Fat Man devices identical to the one used in the bombing of Nagasaki. The nuclear weapons were handmade devices, and a great deal of work remained to improve their ease of assembly, safety, reliability and storage before they were ready for production. There were also many improvements to their performance that had been suggested or recommended, but that had not been possible under the pressure of wartime development. The Chairman of the Joint Chiefs of Staff, Fleet Admiral William D. Leahy had decried the use of the atomic bombs as adopting "an ethical standard common to the barbarians of the Dark Ages", but in October 1947, he reported a military requirement for 400 bombs.  The American monopoly on nuclear weapons lasted only four years before the Soviet Union detonated an atomic bomb in September 1949. The United States responded with the development of the hydrogen bomb, a nuclear weapon a thousand times as powerful as the bombs that devastated Hiroshima and Nagasaki. Such ordinary fission bombs would henceforth be regarded as small tactical nuclear weapons. By 1986, the United States had 23,317 nuclear weapons, while the Soviet Union had 40,159. By 2017, nine nations had nuclear weapons, but Japan was not one of them. Japan reluctantly signed the Treaty on the Non-Proliferation of Nuclear Weapons in February 1970, but it is still sheltered under the American nuclear umbrella. American nuclear weapons were stored on Okinawa, and sometimes in Japan itself, albeit in contravention of agreements between the two nations. Lacking the resources to fight the Soviet Union using conventional forces, the Western Alliance came to depend on the use of nuclear weapons to defend itself during the Cold War, a policy that became known in the 1950s as the New Look. In the decades after Hiroshima and Nagasaki, the United States would threaten to use its nuclear weapons many times.

The United States detonated two nuclear weapons over the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, respectively, with the consent of the United Kingdom, as required by the Quebec Agreement. The two bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the only uses of nuclear weapons in armed conflict.

广岛与长崎原子弹爆炸发生在第二次世界大战末期,美军在1945年8月6日与8月9日,分别在日本的广岛市和长崎市投下两枚原子弹,造成数十万日本平民死亡。这是人类历史第一次在战争中使用核武器,并促使日本投降及第二次世界大战结束。


Fields of application.

Stimulus–response models are applied in international relations, risk assessment, neurally-inspired system design, and many other fields.  Pharmacological dose response relationships are an application of stimulus-response models.

Mathematical formulation.

The object of a stimulus–response model is to establish a mathematical function that describes the relation "f" between the stimulus "x" and the expected value (or other measure of location) of the response "Y":  A common simplification assumed for such functions is linear, thus we expect to see a relationship like  Statistical theory for linear models has been well developed for more than fifty years, and a standard form of analysis called linear regression has been developed.

Bounded response functions.

Since many types of response have inherent physical limitations (e.g. minimal maximal muscle contraction), it is often applicable to use a bounded function (such as the logistic function) to model the response. Similarly, a linear response function may be unrealistic as it would imply arbitrarily large responses. For binary dependent variables, statistical analysis with regression methods such as the probit model or logit model, or other methods such as the Spearman-Karber method. Empirical models based on nonlinear regression are usually preferred over the use of some transformation of the data that linearizes the stimulus-response relationship.  One example of a logit model for the probability of a response to the real input (stimulus) formula_3, (formula_4) is  where formula_6 are the parameters of the function.  Conversely, a Probit model would be of the form  where formula_8 is the cumulative distribution function of the normal distribution.

Hill equation.

In biochemistry and pharmacology, the Hill equation refers to two closely related equations, one of which describes the response (the physiological output of the system, such as muscle contraction) to Drug or Toxin, as a function of the drug's concentration. The Hill equation is important in the construction of dose-response curves. The Hill equation is the following formula, where formula_9 is the magnitude of the response, <chem>[A]</chem> is the drug concentration (or equivalently, stimulus intensity), formula_10 is the drug concentration that produces a half-maximal response and formula_11 is the Hill coefficient.  Note that the Hill equation rearranges to a logistic function with respect to the logarithm of the dose (similar to a logit model).

The stimulus–response model is a characterization of a statistical unit (such as a neuron). The model allows the prediction of a quantitative response to a quantitative stimulus, for example one administered by a researcher. In psychology, stimulus response theory concerns forms of classical conditioning in which a stimulus becomes paired response in a subject's mind.

刺激-反应模型 (stimulus–response model)是将统计单元(例如神经元)用黑箱模型来表示,以预测在特定量化刺激下的量化反应。


History.

Founding.

In 1823, Sir George Birkbeck, a physician and graduate of the University of Edinburgh and an early pioneer of adult education, founded the then "London Mechanics' Institute" at a meeting at the Crown and Anchor Tavern on the Strand. More than two thousand people attended. However the idea was not universally popular and some accused Birkbeck of "scattering the seeds of evil."  In 1825, two years later, the institute moved to the Southampton Buildings on Chancery Lane. In 1830, the first female students were admitted. In 1858, changes to the University of London's structure resulting in an opening up of access to the examinations for its degree. The Institute became the main provider of part-time university education.  In 1866, the Institute changed its name to the Birkbeck Literary and Scientific Institution.  In 1885, Birkbeck moved to the Breams Building, on Fetter Lane, where it would remain for the next sixty-seven years.  In 1904, Birkbeck Students' Union was established.

Birkbeck College.

In 1907, Birkbeck's name was shortened to "Birkbeck College". In 1913, a review of the University of London (which had been restructured in 1900) successfully recommended that Birkbeck become a constituent college, although the outbreak of the First World War delayed this until 1920. The Royal Charter was granted in 1926.  In 1921, the college's first female professor, Dame Helen Gwynne-Vaughan, began teaching botany. Other distinguished faculty in the inter-war years included Nikolaus Pevsner, J. D. Bernal, and Cyril Joad.  During the Second World War, Birkbeck was the only central University of London college not to relocate out of the capital. In 1941, the library suffered a direct hit during The Blitz but teaching continued. During the war the College organised lunch time extramural lectures for the public given by, among others, Joad, Pevsner and Harold Nicolson.  In 1952, the college moved to its present location in Malet Street.

Current status.

In 2002, the university was renamed Birkbeck, University of London, having dropped the word "College" from its branding, but "Birkbeck College, University of London" remains the institution's formal legal name. In 2003, following a major redevelopment, its Malet Street building was reopened by the Chancellor of the University of London, The Princess Royal.  In 2006, Birkbeck announced that it had been granted £5 million by the Higher Education Funding Council for England to expand its provision into east London, working with the University of East London. The partnership was formally launched on 21 November 2006 and is called Birkbeck Stratford.  Birkbeck is one of the largest colleges of the University of London not to award its own degrees. Although it has held its own degree awarding powers since 2012, Birkbeck has chosen to hold these in reserve, preferring to award University of London degrees. It also offers many continuing education courses leading to certificates and diplomas, foundation degrees, and short courses.

The School of Continuing Education.

In 1876, the London Society for the Extension of University Education was founded, boosting the aims of encouraging working people to undertake higher education. In 1988, the Department of Extra-Mural Studies of the University of London was incorporated into Birkbeck, becoming at first the Centre for Extramural Studies. In 1903, it became the Department of Extra-Mural Studies of the University of London and it was integrated into Birkbeck in 1988 as the School of Continuing Education. In 2009, the Faculty of Lifelong Learning was incorporated into the main College structure.

Campus and location.

Birkbeck is principally located between Malet Street and Woburn Square in Bloomsbury, with a number of institutes, teaching hospitals, and scientific laboratories on nearby streets. The Friends House is also partially owned by Birkbeck Law School. The School of Arts, including the Department of English & Humanities, is housed in Virginia Woolf's former Gordon Square residence in Bloomsbury. Other notable former residents of this house include John Maynard Keynes, Vanessa Bell, and Lydia Lopokova. The Gordon Square building includes the Birkbeck Cinema and the Peltz Gallery.  Many Birkbeck classes are taught at other locations around the Bloomsbury area, due to a combination of Birkbeck's widening participation strategy to make higher education accessible and also because nearly all classes on one day are taught at the same time, resulting in heavy competition for limited space.  Birkbeck expanded into east London, in conjunction with the University of East London. The project is known as Birkbeck Stratford. The campus officially opened in November 2013.

Organisation.

Faculties and departments.

The University consists of five schools that comprise a total of 19 diverse academic departments, which are:

Academic profile.

Research and teaching.

The Birkbeck Institute for the Humanities (BIR) was established in 2004, with the renowned but controversial Slovenian philosopher Slavoj Žižek appointed as International Director. According to its website, the Institute aims to, among other things, "engage with important public issues of our time through a series of open debates, lectures, seminars and conferences" and "foster and promote a climate of interdisciplinary research and collaboration among academics and researchers". The launch of the Institute wasn't without controversy, provoking an article in "The Observer" newspaper titled "What have intellectuals ever done for the world?" which criticised the ostensible irrelevance and elitism of contemporary public intellectuals. The current director of the institute is Costas Douzinas. 2004 also saw Birkbeck enter into a research and teaching collaboration with the Institute of Education, jointly founding the London Knowledge Lab. This interdisciplinary research institute brings together social scientists and computer scientists to address research questions about technology and learning.  Meanwhile, the London Consortium graduate school — a collaboration between Birkbeck, the Tate Galleries, the Institute of Contemporary Arts, the Architectural Association, and, until 1999, the British Film Institute – has been running since the mid-1990s, offering masters and doctoral degrees in the interdisciplinary humanities and cultural studies, resourced and jointly taught by all the participating institutions. Its permanent and adjunct faculty include figures such as Tom McCarthy, Colin MacCabe, Laura Mulvey, Steven Connor, Marina Warner, Juliet Mitchell, Stuart Hall, Roger Scruton, Salman Rushdie, Tilda Swinton as well as Slavoj Žižek. Its current chair is Anthony Julius. Since 2003, when David Latchman of UCL became Master of the Birkbeck, he has forged closer relations between these two University of London colleges, and personally maintains departments at both. Joint research centres include the UCL/Birkbeck Institute for Earth and Planetary Sciences, UCL/Birkbeck/IoE Centre for Educational Neuroscience, UCL/Birkbeck Institute of Structural and Molecular Biology, and Birkbeck-UCL Centre for Neuroimaging.  Science research at Birkbeck has a notable tradition. Physicist David Bohm who made notable contributions to the theory of Quantum mechanics was professor of Theoretical Physics from 1961–87, Nobel Laureates Aaron Klug at the Department of crystallography, Derek Barton at the Department of Chemistry together with eminent physicist Roger Penrose and David Bohm at the Department of Physics. Computer scientist Kathleen Booth wrote the first assembly language. Birkbeck is part of the Institute of Structural Molecular Biology, which includes the Bloomsbury Centre for Structural biology, established in 1998. This is a collaborative venture between Birkbeck College and University College London and is a leading academic centre for translating gene sequences and determining protein structure and function. It also includes the Bloomsbury Centre for Bioinformatics, a collaborative venture also between Birkbeck College and University College London for research into Bioinformatics, Genomics, Systems Biology, GRID computing and Text mining.  Birkbeck was ranked 13th in "The Guardian's" 2001 Research Assessment Exercise and 26th in the "Times Higher Education's" equivalent table. In the 2008 RAE results, Birkbeck ranked in the top 25% of UK multi-faculty Higher Education Institutions. The RAE rated the quality of research in a range of subjects at 159 Higher Education Institutions in the UK. Birkbeck submissions from Earth Sciences, Psychology, History, Classics and Archaeology and History of Art, Film and Visual Media were rated in the top five nationally. In REF2014, half of Birkbeck's submissions were rated in the top 20 nationally, and eight submissions received 100% ranking for Research Environment. 73% of Birkbeck's research was rated "world-leading" (4*) or "internationally excellent" (3*).

Rankings.

Birkbeck's Centre for Brain Function and Development was awarded The Queen's Anniversary Prize for its brain research in 2005. In 2010, Birkbeck was shortlisted for the "Times Higher Education" University of the Year Award.  In 2019, the "Times Higher Education World University Rankings" ranked Birkbeck 85th in the world for Psychology. The university is constantly ranked in the top 100 in the world by "QS World University Rankings" for English Language & Literature and Philosophy. Internationally, Birkbeck is ranked within the top 350 universities in the world by the "Times Higher Education World University Rankings 2020" and "QS World University Rankings 2020."  In 2018, Birkbeck announced that it will withdraw from UK university rankings because their methodologies unfairly penalise it, since "despite having highly-rated teaching and research, other factors caused by its unique teaching model and unrelated to its performance push it significantly down the ratings".

Students' Union.

The Birkbeck Students' Union (BBKSU) was founded in 1904 and was one of the founding members of the National Union of Students.  Initially governed by a Council, elected from and responsible to the students, today it is governed jointly by a Student Council, Executive Committee, Board of Trustees and Clubs & Societies Committee.  Students initially paid an annual membership fee to join, but students are now automatically registered as members when they enrol onto a course at the college.  Birkbeck Students' Union offers a number of societies for students, as well as a various sports clubs that compete in the University of London league. It also provides student representation and support, a student magazine, a student shop and a bar. Birkbeck students also have access to the societies and clubs of the Student Central, whose building adjoins Birkbeck's Bloomsbury site.

Birkbeck, University of London (legally Birkbeck College, University of London; informally Birkbeck and abbreviated BBK) is a public research university located in Bloomsbury, London, England, and a constituent college of the federal University of London. Established in 1823 as the London Mechanics' Institute by its founder, Sir George Birkbeck, and its supporters, Jeremy Bentham, J. C. Hobhouse and Henry Brougham, Birkbeck is one of the few universities to specialise in evening higher education in the United Kingdom.

伦敦大学伯贝克学院(Birkbeck, University of London)由George Birkbeck创立于公元1823年。原名为伦敦机械学院(London Mechanics Institute),1907年改名为伯贝克学院,1920年正式加入伦敦大学,2002年重新定名为「Birkbeck, University of London」。伯贝克学院是英国五大不参加商业排名的大学之一(另外四所是伦敦大学学院教育研究院、伦敦商学院、克兰菲尔德大学、苏富比艺术学院)。


Plot.

After their freshman year at college, the four friends regroup for a party held by Stifler, their overtly sex-crazed class clown and good friend. His party is shut down in part to the neighbors calling the police. Kevin is inspired by his brother to make his summer with his friends count by renting a beach home. He, Jim, Oz, and Finch plan to take off to a beach house together, where they intend to spend the summer. Kevin realizes a problem and worked out that they can only afford the house if they have a fifth member to work along with them. Stifler takes charge of much of the organizing, often ending up leading the group in their misadventures.  Oz is miserable, being away from his girlfriend Heather, who is in Spain. During the stay at the beach house, they proceed to start having phone sex to vent some of their loneliness, which ends up being interrupted by Stifler. Heather later shows up early to the party, ending the short storyline that Oz is involved in.  After arriving in Grand Harbor they settle in, they manage to find work painting a house (based on the Tuition Painters franchise) in the area together, mistaking the owners for lesbians. Jim, Stifler and Finch end up performing "like for like" sexual acts on each other in return for being able to watch the girls doing the same thing. Oz and Kevin take turns watching up a ladder and listening on the walkie-talkie also in the room. The conversation is accidentally picked up and heard by many other people in the neighborhood. Finally at the end of the last party, Stifler manages to have a wild threesome with the owners of the house.  After this, many concurrent stories run at the same time, some interacting with each other, others staying mainly separate.  Nadia is coming to visit Jim in August. When she arrives early, Jim asks for help from band geek Michelle, humiliating himself in front of the audience when he pretends to be Petey, a mentally challenged boy who plays the trombone. They pretend to be in a relationship so that Nadia will not expect Jim to have sex (Jim is involved in an incident involving a tube of super glue he mistook for lube; he accidentally glued his hand to his penis while watching a porno film and injured himself, leaving him wounded and unable to perform). Jim and Michelle break the mock relationship off once he is ready to have sex with Nadia, but by then Michelle has really fallen in love with Jim, and soon Jim realizes that he has found his soul-mate in Michelle. Nadia also realizes this and tells him, "Go, get your band geek, and I will find mine". Jim goes and plays the trombone once more whilst Michelle is playing the flute at a major recital in order to show her that she is the one he wants to be with.  Finch has become involved in the sexual art of Tantra, and claims that through Tantra he can "make an orgasm last for days". He is waiting for Stifler's Mom, who he had sex with in the first film, hoping she will show up and be willing to do it again. He thinks she arrives when a vehicle turns up after Stifler is talking on the phone, but it turns out to be his younger brother. He spends the night talking with a few girls, but he doesn't sleep with any of them.  The geeky Sherman gives up on getting anyone after he is turned down by the experienced and sharp-tongued Jessica, but the rejected Nadia, who wanted Jim because he was a geek, is turned on by his "Sherminator" gimmick, and they end up in bed together. Kevin doesn't end up "getting off" with anyone, but he does seem to succeed in getting over Vicky after making advances on her throughout the film.  The next morning, after the party, a Mercedes-Benz coupe with darkened windows turns up, Finch approaches and it turns out Stifler's Mom has come after all. He jumps at the chance and they drive off together, Stifler not realizing until after the car has driven off that it was Finch and his mother. After being asked, she reveals her name is Jeanine, but also instructs Finch to resume calling her "Stifler's mom" as per usual.

Production.

Principal photography began on February 14 and wrapped on April 27, 2001. Two versions of the film were released: the R-rated theatrical version and the unrated version. To ensure an R rating, the film was cut slightly. Altogether 19 scenes were altered.

Reception.

Box office.

During the opening weekend, the film grossed $45.1 million from 3,063 theaters in the United States, ranking #1 at the box office ahead of "Rush Hour 2". The film has grossed $145,103,595 in the United States and $142,450,000 in foreign countries adding to total worldwide gross of $287,553,595.

Critical response.

"American Pie 2" has received mixed reviews from critics. On Rotten Tomatoes the film has a 52% rating based on 127 reviews. The website's consensus states: "Being a sequel, "American Pie 2" doesn't retain the freshness of the original, nor is it as funny." On Metacritic the film has a score of 43/100 based on reviews from 28 critics, indicating "mixed or average reviews". Audiences surveyed by CinemaScore gave the film a rating of B+, on a scale from A to F.  Roger Ebert gave the film 3 out of 4 stars. Roger Ebert and Richard Roeper both gave the film "Two thumbs up", Richard Roeper stated that there were "More Laughs than the original!"

Home media.

"American Pie 2" was released on VHS and DVD on January 15, 2002. The movie was released in two different versions: an R-rated version and an unrated version.  The following songs were included in the movie but were not featured on the soundtrack:

American Pie 2 is a 2001 American sex comedy film directed by James B. Rogers and written by Adam Herz and David H. Steinberg from a story by Herz. A sequel to the 1999 comedy film "American Pie", it is the second film in the "American Pie" series and stars Jason Biggs, Shannon Elizabeth, Alyson Hannigan, Chris Klein, Natasha Lyonne, Thomas Ian Nicholas, Tara Reid, Seann William Scott, Mena Suvari, Eddie Kaye Thomas, and Eugene Levy. The film follows the sexual exploits of five friends—Jim, Kevin, Stifler, Oz, and Finch—and their attempts to have the greatest summer party ever, at a summer beach house in Grand Haven, Michigan.

《美国派2》(英语:American Pie 2)是2001年的一部美国喜剧电影,是1999年电影美国派的续集。电影于2001年8月10日在美国首映。


Equation.

When a beam of light is partly blocked by an obstacle, some of the light is scattered around the object, light and dark bands are often seen at the edge of the shadow – this effect is known as diffraction. These effects can be modelled using the Huygens–Fresnel principle. Huygens postulated that every point on a primary wavefront acts as a source of spherical secondary wavelets and the sum of these secondary wavelets determines the form of the proceeding wave at any subsequent time. Fresnel developed an equation using the Huygens wavelets together with the principle of superposition of waves, which models these diffraction effects quite well.  It is not a straightforward matter to calculate the displacement (amplitude) given by the sum of the secondary wavelets, each of which has its own amplitude and phase, since this involves addition of many waves of varying phase and amplitude. When two waves are added together, the total displacement depends on both the amplitude and the phase of the individual waves: two waves of equal amplitude which are in phase give a displacement whose amplitude is double the individual wave amplitudes, while two waves which are in opposite phases give a zero displacement. Generally, a two-dimensional integral over complex variables has to be solved and in many cases, an analytic solution is not available.  The Fraunhofer diffraction equation is a simplified version of the Kirchhoff's diffraction formula and it can be used to model the light diffracted when both a light source and a viewing plane (the plane of observation) are effectively at infinity with respect to a diffracting aperture. With the sufficiently distant light source from the aperture, the incident light to the aperture is a plane wave so that the phase of the light at each point on the aperture is the same. The phase of the contributions of the individual wavelets in the aperture varies linearly with position in the aperture, making the calculation of the sum of the contributions relatively straightforward in many cases.  With a distant light source from the aperture, the Fraunhofer approximation can be used to model the diffracted pattern on a distant plane of observation from the aperture (far field). Practically it can be applied to the focal plane of a positive lens.

Far field.

When the distance between the aperture and the plane of observation (on which the diffracted pattern is observed) is large enough so that the optical path lengths from edges of the aperture to a point of observation differ much less than the wavelength of the light, then propagation paths for individual wavelets from every point on the aperture to the point of observation can be treated as parallel. This is often known as the far field and is defined as being located at a distance which is significantly greater than, where is the wavelength and is the largest dimension in the aperture. The Fraunhofer equation can be used to model the diffraction in this case.  For example, if a 0.5 mm diameter circular hole is illuminated by a laser with 0.6 μm wavelength, the Fraunhofer diffraction equation can be employed if the viewing distance is greater than 1000 mm.

Focal plane of a positive lens as the far field plane.

In the far field, propagation paths for wavelets from every point on an aperture to a point of observation are approximately parallel, and a positive lens (focusing lens) focuses parallel rays toward the lens to a point on the focal plane (the focus point position on the focal plane depends on the angle of the parallel rays with respect to the optical axis). So, if a positive lens with a sufficiently long focal length (so that differences between electric field orientations for wavelets can be ignored at the focus) is placed after an aperture, then the lens practically makes the Fraunhofer diffraction pattern of the aperture on its focal plane as the parallel rays meet each other at the focus.

Examples of Fraunhofer diffraction.

In each of these examples, the aperture is illuminated by a monochromatic plane wave at normal incidence.

Diffraction by a slit of infinite depth.

The width of the slit is. The Fraunhofer diffraction pattern is shown in the image together with a plot of the intensity vs. angle. The pattern has maximum intensity at, and a series of peaks of decreasing intensity. Most of the diffracted light falls between the first minima. The angle,, subtended by these two minima is given by:  Thus, the smaller the aperture, the larger the angle subtended by the diffraction bands. The size of the central band at a distance is given by  For example, when a slit of width 0.5 mm is illuminated by light of wavelength 0.6 μm, and viewed at a distance of 1000 mm, the width of the central band in the diffraction pattern is 2.4 mm.  The fringes extend to infinity in the direction since the slit and illumination also extend to infinity.  If, the intensity of the diffracted light does not fall to zero, and if, the diffracted wave is cylindrical.

Semi-quantitative analysis of single-slit diffraction.

We can find the angle at which a first minimum is obtained in the diffracted light by the following reasoning. Consider the light diffracted at an angle where the distance is equal to the wavelength of the illuminating light. The width of the slit is the distance. The component of the wavelet emitted from the point A which is travelling in the direction is in anti-phase with the wave from the point at middle of the slit, so that the net contribution at the angle from these two waves is zero. The same applies to the points just below and, and so on. Therefore, the amplitude of the total wave travelling in the direction is zero. We have:  The angle subtended by the first minima on either side of the centre is then, as above:  There is no such simple argument to enable us to find the maxima of the diffraction pattern.

Single-slit diffraction of Electric Field using Huygen's Principle.

We can develop an expression for the far field of a continuous array of point sources of uniform amplitude and of the same phase. Let the array of length "a" be parallel to the y axis with its center at the origin as indicated in the figure to the right. Then the differential field is:  formula_5  where formula_6. However formula_7and integrating from formula_8 to formula_9,  formula_10  where formula_11.  Integrating we then get  formula_12  Letting formula_13where the array length in radformula_14, then,  formula_15

Diffraction by a rectangular aperture.

The form of the diffraction pattern given by a rectangular aperture is shown in the figure on the right (or above, in tablet format). There is a central semi-rectangular peak, with a series of horizontal and vertical fringes. The dimensions of the central band are related to the dimensions of the slit by the same relationship as for a single slit so that the larger dimension in the diffracted image corresponds to the smaller dimension in the slit. The spacing of the fringes is also inversely proportional to the slit dimension.  If the illuminating beam does not illuminate the whole vertical length of the slit, the spacing of the vertical fringes is determined by the dimensions of the illuminating beam. Close examination of the double-slit diffraction pattern below shows that there are very fine horizontal diffraction fringes above and below the main spot, as well as the more obvious horizontal fringes.

Diffraction by a circular aperture.

The diffraction pattern given by a circular aperture is shown in the figure on the right. This is known as the Airy diffraction pattern. It can be seen that most of the light is in the central disk. The angle subtended by this disk, known as the Airy disk, is  where is the diameter of the aperture.  The Airy disk can be an important parameter in limiting the ability of an imaging system to resolve closely located objects.

Diffraction by an aperture with a Gaussian profile.

The diffraction pattern obtained given by an aperture with a Gaussian profile, for example, a photographic slide whose transmissivity has a Gaussian variation is also a Gaussian function. The form of the function is plotted on the right (above, for a tablet), and it can be seen that, unlike the diffraction patterns produced by rectangular or circular apertures, it has no secondary rings. This technique can be used in a process called apodization—the aperture is covered by a Gaussian filter, giving a diffraction pattern with no secondary rings.  The output profile of a single mode laser beam may have a Gaussian intensity profile and the diffraction equation can be used to show that it maintains that profile however far away it propagates from the source.

Diffraction by a double slit.

In the double-slit experiment, the two slits are illuminated by a single light beam. If the width of the slits is small enough (less than the wavelength of the light), the slits diffract the light into cylindrical waves. These two cylindrical wavefronts are superimposed, and the amplitude, and therefore the intensity, at any point in the combined wavefronts depends on both the magnitude and the phase of the two wavefronts. These fringes are often known as Young's fringes.  The angular spacing of the fringes is given by  The spacing of the fringes at a distance from the slits is given by  where is the separation of the slits.  The fringes in the picture were obtained using the yellow light from a sodium light (wavelength = 589 nm), with slits separated by 0.25 mm, and projected directly onto the image plane of a digital camera.  Double-slit interference fringes can be observed by cutting two slits in a piece of card, illuminating with a laser pointer, and observing the diffracted light at a distance of 1 m. If the slit separation is 0.5 mm, and the wavelength of the laser is 600 nm, then the spacing of the fringes viewed at a distance of 1 m would be 1.2 mm.

Semi-quantitative explanation of double-slit fringes.

The difference in phase between the two waves is determined by the difference in the distance travelled by the two waves.  If the viewing distance is large compared with the separation of the slits (the far field), the phase difference can be found using the geometry shown in the figure. The path difference between two waves travelling at an angle is given by  When the two waves are in phase, i.e. the path difference is equal to an integral number of wavelengths, the summed amplitude, and therefore the summed intensity is maximal, and when they are in anti-phase, i.e. the path difference is equal to half a wavelength, one and a half wavelengths, etc., then the two waves cancel, and the summed intensity is zero. This effect is known as interference.  The interference fringe maxima occur at angles  where λ is the wavelength of the light. The angular spacing of the fringes is given by  When the distance between the slits and the viewing plane is, the spacing of the fringes is equal to and is the same as above:

Diffraction by a grating.

A grating is defined in Born and Wolf as "any arrangement which imposes on an incident wave a periodic variation of amplitude or phase, or both".  A grating whose elements are separated by diffracts a normally incident beam of light into a set of beams, at angles given by:  This is known as the grating equation. The finer the grating spacing, the greater the angular separation of the diffracted beams.  If the light is incident at an angle, the grating equation is:  The detailed structure of the repeating pattern determines the form of the individual diffracted beams, as well as their relative intensity while the grating spacing always determines the angles of the diffracted beams.  The image on the right shows a laser beam diffracted by a grating into = 0, and ±1 beams. The angles of the first order beams are about 20°; if we assume the wavelength of the laser beam is 600 nm, we can infer that the grating spacing is about 1.8 μm.

Semi-quantitative explanation.

A simple grating consists of a series of slits in a screen. If the light travelling at an angle from each slit has a path difference of one wavelength with respect to the adjacent slit, all these waves will add together, so that the maximum intensity of the diffracted light is obtained when:  This is the same relationship that is given above.

In optics, the Fraunhofer diffraction equation is used to model the diffraction of waves when the diffraction pattern is viewed at a long distance from the diffracting object, and also when it is viewed at the focal plane of an imaging lens. In contrast, the diffraction pattern created near the object, in the near field region, is given by the Fresnel diffraction equation.

在光学上,夫琅禾费衍射(以约瑟夫·冯·夫琅和费命名),又称远场衍射,是波动衍射的一种,在场波通过圆孔或狭缝时发生,导致观测到的成像大小有所改变,成因是观测点的远场位置,及通过圆孔向外的衍射波有渐趋平面波的性质。


Early life.

Born in Waterbury, Connecticut, on October 2, 1949, Anna-Lou Leibovitz is the third of six children of Marilyn Edith (née Heit) and Samuel Leibovitz. She is a third-generation American. Her father was a lieutenant colonel in the U.S. Air Force of Romanian Jewish heritage and her mother was a modern dance instructor of Estonian-Jewish heritage. The family moved frequently with her father's duty assignments, and she took her first pictures when he was stationed in the Philippines during the Vietnam War. Leibovitz's passion for art was born out of her mother's engagement with dance, music, and painting.  While attending Northwood High School in Silver Spring, Maryland, she became interested in various artistic endeavors and began to write and play music.

Education.

Leibovitz attended the San Francisco Art Institute, where she studied painting with the intention of becoming an art teacher. At school, she had her first photography workshop and changed her major to photography. She was inspired by the work of Robert Frank and Henri Cartier-Bresson. For several years, she continued to develop her photography skills while holding various jobs, including a stint on a kibbutz in Amir, Israel, for several months in 1969.

Career.

For many years Leibovitz's camera of choice was a Mamiya RZ67. She also has used the following cameras:

1970–1980.

"Rolling Stone".

When Leibovitz returned to the United States in 1970, she started her career as staff photographer for "Rolling Stone" magazine. In 1973, publisher Jann Wenner named Leibovitz chief photographer of "Rolling Stone", a job she would hold for 10 years. Leibovitz worked for the magazine until 1983, and her intimate photographs of celebrities helped define the "Rolling Stone" look.  While working for "Rolling Stone", Leibovitz learned that she could work for magazines and still create personal work of her family, which for her was the most important: "You don't get the opportunity to do this kind of intimate work except with the people you love, the people who will put up with you. They’re the people who open their hearts and souls and lives to you. You must take care of them."

The Rolling Stones.

Leibovitz photographed the Rolling Stones in San Francisco in 1971 and 1972, and served as the concert-tour photographer for the Rolling Stones' Tour of the Americas '75. Her favorite photo from the tour was a photo of Mick Jagger in an elevator.

John Lennon.

On December 8, 1980, Leibovitz had a photo shoot with John Lennon for "Rolling Stone", and she promised him he would make the cover. She had initially tried to get a picture with just Lennon alone, as "Rolling Stone" wanted, but Lennon insisted that both he and Yoko Ono be on the cover. Leibovitz then tried to re-create something like the kissing scene from the couple's "Double Fantasy" 1980 album cover, a picture Leibovitz loved. She had John remove his clothes and curl up next to Yoko on the floor. Leibovitz recalls, What is interesting is she said she'd take her top off and I said, "Leave everything on"— not really preconceiving the picture at all. Then he curled up next to her and it was very, very strong. You couldn't help but feel that he was cold and he looked like he was clinging on to her. I think it was amazing to look at the first Polaroid and they were both very excited. John said, "You've captured our relationship exactly. Promise me it'll be on the cover." I looked him in the eye and we shook on it.Leibovitz was the last person to professionally photograph Lennon — he was shot and killed five hours later.  A month or so later, "Rolling Stone" magazine gave grieving music fans his "last image". The photograph was subsequently re-created in 2009 by John and Yoko's son Sean Lennon posing with his girlfriend Charlotte Kemp Muhl, with male/female roles reversed (Sean clothed, Kemp naked), and by Henry Bond and Sam Taylor-Wood in their YBA pastiche October 26, 1993.

1980–2000.

Leibovitz's new style of lighting and use of bold colors and poses got her a position with "Vanity Fair" magazine in 1983.  Leibovitz photographed celebrities for an international advertising campaign for American Express charge cards, which won a Clio award in 1987.  In 1991, Leibovitz mounted an exhibition at the National Portrait Gallery. She was the second living portraitist and first woman to show there. That same year, Leibovitz was also made Commandeur de l'Ordre des Arts et des Lettres by the French government. Also in 1991, Leibovitz emulated Margaret Bourke-White's feat by mounting one of the eagle gargoyles on the 61st floor of the Chrysler Building in Manhattan, where she photographed the dancer David Parsons cavorting on another eagle gargoyle. Noted "Life" photographer and picture editor John Loengard made a gripping photo of Leibovitz at the climax of her danger (Loengard was photographing Leibovitz for "The New York Times" that day).  In 1998, Annie began to work regularly for "Vogue".

2000–present.

Brooklyn Museum retrospective.

In 2007, a major retrospective of Leibovitz's work was held at the Brooklyn Museum. The retrospective was based on her book, "Annie Leibovitz: A Photographer's Life, 1990–2005" and included many of her professional (celebrity) photographs and numerous personal photographs of her family, children, and partner Susan Sontag. This show, which was expanded to include three official portraits of Queen Elizabeth II, then went on the road for seven stops. It was on display at the Corcoran Gallery of Art in Washington, D.C., from October 2007 to January 2008 and at the Palace of the Legion of Honor in San Francisco from March 2008 to May 2008. In February 2009, the exhibition was moved to Berlin, Germany. The show included 200 photographs. This exhibition and her talk focused on her personal photographs and life.

Queen Elizabeth controversy.

In 2007, the BBC misrepresented Leibovitz's portrait shooting of Queen Elizabeth II to take the Queen's official picture for her state visit to Virginia. This was filmed for the BBC documentary "A Year with the Queen". A promotional trailer for the film showed the Queen reacting angrily to Leibovitz's suggestion ("less dressy") that she remove her tiara, then a scene of the Queen walking down a corridor, telling an aide "I'm not changing anything. I've had enough dressing like this, thank you very much." The BBC later apologized and admitted that the sequence of events had been misrepresented, as the Queen was in fact walking to the sitting in the second scene. This led to a BBC scandal and a shake-up of ethics training. However a 2015 "London Times" article contradicts this story. It stated that the Queen was both incredulous at being asked to remove her crown as "no-one tells her what to do" and insulted as the item was only a tiara.

Miley Cyrus photoshoot controversy.

On April 25, 2008, "Entertainment Tonight" reported that 15-year-old Miley Cyrus had posed topless for a photo shoot with "Vanity Fair". The photograph and subsequently released behind-the-scenes photographs show Cyrus topless, her bare back exposed but her front covered with a bedsheet. The photo was taken by Leibovitz. The full photograph was published with an accompanying story on "The New York Times"' website on April 27, 2008. On April 29, 2008, "The New York Times" clarified: though the pictures left an impression that she was bare-breasted, Cyrus was wrapped in a bedsheet and was actually not topless. Some parents expressed outrage at the nature of the photograph, which a Disney spokesperson described as "a situation [that] was created to deliberately manipulate a 15-year-old in order to sell magazines". In response to the Internet circulation of the photo and ensuing media attention, Cyrus released a statement of apology on April 27: "I took part in a photo shoot that was supposed to be 'artistic' and now, seeing the photographs and reading the story, I feel so embarrassed. I never intended for any of this to happen and I apologize to my fans who I care so deeply about." Leibovitz also released a statement saying: "I'm sorry that my portrait of Miley has been misinterpreted... The photograph is a simple, classic portrait, shot with very little makeup, and I think it is very beautiful."

Pirelli calendar.

In 2015, Leibovitz was the principal photographer for the 2016 Pirelli calendar. Leibovitz took a drastic shift from the calendar traditional style by focusing on admirable women as opposed to sexuality. The calendar included Amy Schumer, Serena Williams, and Patti Smith. Leibovitz had previously worked on the 2000 calendar.

Personal life.

Children.

Leibovitz has three daughters. Her first, Sarah Cameron Leibovitz was born in October 2001 when Leibovitz was 52 years old. Twin girls Susan and Samuelle were born to a surrogate mother in May 2005.

Relationships.

Leibovitz had a close relationship with writer and essayist Susan Sontag from 1989 until Sontag's death in 2004. During Sontag's lifetime, neither woman publicly disclosed whether the relationship was a platonic friendship or romantic. In 2006, "Newsweek" magazine made reference to Leibovitz's decade-plus relationship with Sontag, stating, "The two first met in the late '80s, when Leibovitz photographed her for a book jacket. They never lived together, though they each had an apartment within view of the other's." When Leibovitz was interviewed for her autobiography "A Photographer's Life: 19902005", she said that the book told a number of stories, and "with Susan, it was a love story." While "The New York Times" in 2009 referred to Sontag as Leibovitz's "companion", Leibovitz wrote in "A Photographer's Life": "words like 'companion' and 'partner' were not in our vocabulary. We were two people who helped each other through our lives. The closest word is still 'friend'." That same year, Leibovitz said the descriptor "lover" was accurate. She later reiterated: "Call us 'lovers'. I like 'lovers.' You know, 'lovers' sounds romantic. I mean, I want to be perfectly clear. I love Susan."

Religion.

When asked if being Jewish is important to her, Leibovitz replied, "I'm not a practicing Jew, but I feel very Jewish."

Financial troubles.

In February 2009, Leibovitz borrowed, after having experienced financial challenges, putting up several houses as well as the rights to all of her photographs as collateral. "The New York Times" noted that "one of the world's most successful photographers essentially pawned every snap of the shutter she had made or will make until the loans are paid off", and that, despite a archive, Leibovitz had a "long history of less than careful financial dealings" and "a recent series of personal issues" including the loss of her parents and the 2004 death of Sontag, as well as the addition of two children to her family, and controversial renovation of three Greenwich Village properties.  The Greenwich Village properties, at 755757 Greenwich Street, are part of the Greenwich Village Historic District, and thus the New York City Landmarks Preservation Commission must review and approve any work done to the buildings. However, work initiated on the buildings in October 2002, without a permit, began a chain of destruction of those buildings and the neighbor's at 311 W 11th Street. Due to pressure from the Greenwich Village Society for Historic Preservation and other groups, the buildings were finally stabilized, though the preservation group criticized the eventual repairs as shoddy and historically insensitive.  In July 2009, the Art Capital Group filed a breach of contract lawsuit against Leibovitz for regarding repayment of these loans. In a follow-up article from September 5, 2009, an Associated Press story quoted legal experts as saying that filing for bankruptcy reorganization might offer Leibovitz her best chance to control and direct the disposition of her assets to satisfy debts. On September 11, Art Capital Group withdrew its lawsuit against Leibovitz and extended the due date for repayment of the loan. Under the agreement, Leibovitz retains control over her work and will be the "exclusive agent in the sale of her real property (land) and copyrights".  In March 2010, Colony Capital concluded a new financing and marketing agreement with Leibovitz, paying off Art Capital and removing or reducing the risks to Leibovitz of losing her artistic works and real estate. The following month, Brunswick Capital Partners sued Leibovitz, claiming it was owed several hundred thousand dollars for helping her restructure her debt. In December 2012, Leibovitz listed her West Village townhouse for sale at $33 million, stating she wanted to move closer to her daughter.

Anna-Lou "Annie" Leibovitz (; born October 2, 1949) is an American portrait photographer. She is best known for her engaging portraits, particularly of celebrities, which often feature subjects in intimate settings and poses. Leibovitz's polaroid of John Lennon and Yoko Ono, taken five hours before Lennon's murder, is considered "Rolling Stone" magazine's most famous cover photograph. The Library of Congress declared her a Living Legend, and she is the first woman to have a feature exhibition at Washington's National Portrait Gallery.

安妮·莱柏维兹(英语:Annie Leibovitz, 1949年-10月2日),本名安娜-露·莱柏维兹,美国肖像摄影师。


Early life.

Childhood, family and first marriage (1904–24).

María de los Dolores Asúnsolo y López-Negrete was born in Victoria de Durango, Mexico on August 3, 1904, the daughter of Jesus Leonardo Asúnsolo Jacques, son of wealthy farmers and director of the Bank of Durango, and Antonia López-Negrete, belonging to one of the richest families in the country, whose lineage went back to Spain and the viceregal nobility.  Her parents were members of the Mexican aristocracy that existed during the Porfiriato (period in the history of Mexico when the dictator Porfirio Díaz was the

Career.

Film debut and early success (1925–30).

In early 1925, Dolores met the American filmmaker Edwin Carewe, an influential director at the First National studio, who was in Mexico for the wedding of actors Bert Lytell and Claire Windsor. Carewe was fascinated by Dolores and managed to be invited to her home by the artist Adolfo Best Maugard. In the evening Dolores danced and her husband accompanied her on the piano. Carewe was determined to have her, so he invited the couple to work in Hollywood. Carewe convinced Jaime, saying he could turn his wife into a movie star. Jaime thought that this proposal was a response to their economic needs. In Hollywood, he could fulfill his old dream of writing screen plays. Breaking with all the canons of Mexican society at that time and against their family's wishes, they journeyed by train to the United States.  Del Río was contracted by Carewe as her agent, manager, producer and director. Her name was shortened to "Dolores Del Rio" (with an incorrect capital "D" in the word "del"). Carewe arranged for

Transition to sound and second marriage (1930–43).

In 1930, del Río met Cedric Gibbons, an art director at Metro-Goldwyn-Mayer and one of the most influential men in Hollywood, at a party at Hearst Castle. The couple began a romance and finally married on August 6, 1930. The del Rio-Gibbons were one of the most famous couples of Hollywood in the early thirties. They organized 'Sunday brunches' in their fabulous Art Deco mansion, considered one of the most modern and elegant in the high circles of Hollywood. Shortly after her marriage, del Río fell seriously ill with a severe kidney infection. The doctors recommended long bed rest. When she regained her health, she was hired exclusively by RKO Pictures. Her first film with the studio was "Girl of the Rio" (1931), directed by Herbert Brenon.  Producer David O. Selznick called the filmmaker King Vidor and said: "I want del Río and Joel McCrea in a love story in the South Seas. I didn't have much of a story for the film, but be sure that it ends with the young beauty jumping into a volcano." "Bird of Paradise" (1932) was shot in Hawaii and del Río became

Return to Mexico and continued success (1943–59).

She had been sought by Mexican film directors since the late 1930s, but economic circumstances were not favorable for the entry of del Río to the Mexican cinema. She was a friend of Mexican artists (such as Diego Rivera and Frida Kahlo), and maintained ties with Mexican society and cinema. After breaking off her relationship with Welles, del Río returned to Mexico.  As soon as she returned to her country, Mexican director Emilio "El Indio" Fernández invited her to film "Flor silvestre" (1943). Fernandez was her great admirer and he was eager to direct her. This was del Río's first Spanish-language film. The film gathers a successful film crew consisting of Fernandez, the cinematographer Gabriel Figueroa, the screenwriter Mauricio Magdaleno and del Río and Pedro Armendariz as the stars. Subsequently, they filmed "María Candelaria", the first Mexican film to be screened at the Cannes International Film Festival where it won the Grand Prix (now known as the Palme d'Or) becoming the first Latin American film to do so. Fernández has said that he wrote an original version of the plot on 13 napkins while sitting in a restaurant. He was anxious

Final roles and return to Hollywood (1960–78).

In 1957, she debuted in television in the role of a Spanish lady in the American television series "Schlitz Playhouse of Stars", with Cesar Romero. Del Río and her husband founded their own production company called Producciones Visuales. and they produced numerous theater projects featuring del Río. Mexican writer Salvador Novo became the translator of her plays. Her first production in Mexico City was Oscar Wilde's "Lady Windermere's Fan", which she had made as a film in Argentina a decade earlier. She toured Mexico in the play, an enterprise that was both financially and critically successful, and she later took it to Buenos Aires. Others of her successful theater projects were "The Road to Rome" (1958), "Ghosts" (1962), "Dear Liar: A Comedy of Letters" (1963), "La

Death.

In 1978, she was diagnosed with osteomyelitis, and in 1981 she was diagnosed with hepatitis B following a contaminated injection of vitamins. She also suffered from arthritis. In 1982, del Río was admitted to Scripps Hospital, La Jolla, California, where hepatitis led to cirrhosis.  On 11 April

Personal life.

Public image and personality.

Del Río always projected a special elegance with her beauty, more than just a "Latin bombshell" such as other actresses like Lupe Vélez. Del Rio's intrinsic elegance was apparent even off-screen. Del Río strongly identified with her Mexican heritage despite her growing fame and her transition to "modernity". She also felt strongly about being able to play Mexican roles and bemoaned the fact that she was not cast in them. She never relinquished her Mexican citizenship and said in 1929 (at the height of her popularity) that she wanted "to play a Mexican woman and show what life in Mexico really is. No one has shown the artistic side – nor the social". Del Río was considered one of the prototypes of female beauty in the 1930s. In 1933, the American film magazine "Photoplay" conducted a search for "the most perfect female figure in Hollywood", using the criteria of doctors, artists and designers as judges. The "unanimous choice" of these selective arbiters of female beauty was Del Río. The question posed by the search for the magazine and the methodology used to find "the most perfect female figure"

Relationships.

Regardless of her marriages at different times in her life, she was romantically linked with actor Errol Flynn, filmmaker John Farrow, writer Erich Maria Remarque, film producer Archibaldo Burns, and actor Tito Junco.  Her relationship with Orson Welles (1939–1943) ended after four years largely due to his infidelities. Rebecca Welles, the daughter of Welles and Rita Hayworth, expressed her desire to travel to Mexico to meet Dolores. In 1954, Dolores received her at her home in Acapulco. After their meeting, Rebecca said: "My father considered Dolores the great love of his life. She is a living legend in the history of my family." According to Rebecca, until the end of his life, Welles felt for del Río a kind of obsession. Mexican filmmaker Emilio Fernández was one her admirers. He said that he had appeared as an extra in several films of Dolores in Hollywood just to be near her. The beauty and elegance of del Río had impressed him deeply. Fernández said: "I fell in love with her, but she always ignored me. I adored her... really I adored her."  The house of

Philanthropy and cultural ambassador.

In the late 1950s, she became a main promoter of the Acapulco International Film Review, serving as host on numerous occasions. In 1966, del Río was co-founder of the Society for the Protection of the Artistic Treasures of Mexico with the philanthropist Felipe García Beraza. The society was responsible for protecting buildings, paintings and other works of art and culture in México.  On January 8, 1970, she, in collaboration with other renowned Mexican actresses, founded the union group "Rosa Mexicano", which provided a day nursery for the children of the members of the Mexican Actor's Guild. Del Río was responsible for various activities to raise funds for the project and she trained in modern teaching techniques. She served as the president from its founding until 1981. After her death, the day nursery adopted the official name of "Estancia Infantil Dolores del Río (The Dolores del Río Day

Legacy.

Del Río was the first Mexican actress to succeed in Hollywood. The others have been Lupe Vélez, Katy Jurado, and in recent years Salma Hayek and Lupita Nyong'o. Her career had a great impact on the trajectories of the Latinas in Hollywood who followed her. Stars including Hayek, Jennifer Lopez, Sofia Vergara and Penélope Cruz follow the steps forged by Dolores del Río.

In art and literature.

The physical characteristics of Dolores del Río made her a veneration figure even beyond death. From a young age, del Río had the intelligence to know how to surround herself with personalities of the intellectual environment. The Hollywood myth placed del Río in another area, as she became one of the women related to the renaissance of Mexican culture and customs.  The face of Dolores del Río was also the object of veneration for many artists who shaped her image on their canvases. In 1916, when del Río was 11 years old, she was first portrayed by

Filmography and theatre credits.

Select filmography:  Select theatre roles:

Dolores del Río (; born María de los Dolores Asúnsolo López-Negrete; August 3, 1904 – April 11, 1983) was a Mexican actress, dancer and singer. With a career spanning more than 50 years, she is regarded as the first major female Latin American crossover star in Hollywood, with an outstanding career in American cinema in the 1920s and 1930s. She was also considered one of the most important female figures in the Golden Age of Mexican cinema. Del Río is also remembered as one of the most beautiful faces on screen of all time.

多洛莉丝·德尔·里欧(,;1904年-8月3日-1983年-4月11日),全名玛利亚·德·罗斯·多洛莉丝·亚松索洛·洛佩兹-内格雷特(),是一名墨西哥女演员,亦是好莱坞首位拉丁裔跨界明星,曾享誉1920与1930年代的美国电影产业。其同样被视作1940与1950年代墨西哥电影黄金时代的主要女性角色。在里欧活跃的年代,她被视作电影领域最美丽的人物之一,在无声电影、有声电影、电视、戏剧与广播领域有着长久而丰富的生涯。