Experimental study on an all gas-phase iodine laser using microwave discharge of Cl2/He as a Cl atoms source.
Microwave discharge of a Cl2/He mixture as a simple, clean and efficient Cl atom generator was used for an all gas-phase iodine laser study. Sufficient NCl(a1Delta) was produced through the reaction of HN3+2Cl-->NCl(a1Delta)+HCl+N2. The energy transfer reaction of I(2P3/2)+NCl(a1Delta)-->I(2P1/2)+NCl(X3Sigma) was observed. A population inversion was observed directly by using a 1315 nm tunable diode laser by scanning the entire line shape of the (3,4) hyperfine transition of iodine, and a small signal gain of 5x10(-5) cm-1 was obtained.
Kinetics of NCl(a 1 Δ and b 1 Σ + ) Generation: The Cl + N 3 Rate Constant, the NCl(a 1 Δ) Product Branching Fraction, and Quenching of NCl(a 1 Δ) by F and Cl Atoms
The quenching rate constants for NCl(a1Δ) by F and Cl atoms have been measured at room temperature to be (2.2 ± 0.7) × 10-11 and (1.0 + 1.0/−0.5) × 10-12 cm3 s-1, respectively, by adding F and Cl atoms to a flow reactor containing NCl(a1Δ). With knowledge of these quenching rate constants, the kinetics for the formation of NCl(a1Δ) from the Cl + N3 reaction could be investigated in the F/Cl/HN3 reaction system. The reduction in NF(a1Δ) yield from adding Cl atoms to the reactor containing F and HN3 and the relative NF(a1Δ) and NCl(a1Δ) yields for known concentrations of F and Cl atoms in this reaction system favor a total Cl + N3 rate constant of 3 ± 1 × 10-11 cm3 s-1 with a branching fraction for NCl(a1Δ) formation of ≳ 0.5. The branching fraction was deduced from comparing the relative intensities of the NCl(a−X) and NF(a−X) transitions using a lower limit to the NCl(a) radiative lifetime of 2 s. The direct formation of NCl(b1Σ+) from Cl + N3 is a minor channel; however, NCl(b1Σ+) is formed by bimolecula...
Training and maintaining the performance of dogs (Canis familiaris) on an increasing number of odor discriminations in a controlled setting
Abstract The number of substances detector dogs are trained to detect varies depending on the mission of the agency they serve. No studies have been conducted concerning how training multiple odor discriminations affects detection performance and refresher training requirements. This study used a controlled field setting to examine the effects of training dogs to detect multiple substances on their subsequent detection performance and refresher training requirements. Dogs were first trained to detect a single odor. Their detection performance was tested 10 days later and refresher training was then given to bring their performance back up to a predetermined standard. Following refresher training, detection of a new substance was trained, and approximately 10 days later the detection of both trained substances was tested. This sequence of testing, refresher training, and new odor training continued every 10 days until the dogs had been trained and tested on 10 odors. The detection of previously learned odors did not decrease as the number of substances trained increased. In fact, the amount of training required to refresh detection performance and to train new odor discriminations tended to decrease as more odor discriminations were trained.