Temperature control and stabilization in the cryodielectrometer for temperatures 0.5 – 300 K
To meet requirements, which arise while design of equipment for research the dielectric parameters of low-loss materials in the millimeter waveband, the necessity of high-precision temperature stabilization and measurement appear. Despite the fact that a lot of attention [1,2] is devoted to this task already, it reminds still actual, due to a plenty of specific features, which each given measuring complex possess.Thermometers intended to measure low and very low temperatures, as a rule use the temperature dependence of certain physical properties of basis substances. There is known quite large amount of temperature controllers [3-6], which are able to operate in a wide temperature range. However, some of them operate in direct current DC-mode [4], and others, which are used AC-mode, intended for operation in too narrow temperature range ≈ 1 K [3, 6]. Besides, they are able to use only one type of sensor and possess, in our opinion, too complicated feedback scheme for the temperature stabilization [5]. In this paper we consider the scheme of the temperature regulator-stabilizer with two temperature sensors having both positive and negative temperature coefficients of resistance (TCR). It designed for low temperature measurements on the cryodielectrometer “TORNADO” in the temperature range 0.5-300 K. As well results of the low-temperature radiospectroscopy experiment using the device designed are given.
Cryogenic complex for measurement of superflow losses of dielectrics in millimeter waveband
The design and operating principles of experimental set-up for measuring superslow dielectric losses (tg/spl delta/ /spl sim/10-/sup 6/) at temperatures 4.2-0.6K are presented. The set-up consists of "top-loading" refrigerator of evaporation of/sup 3/He with the permanent circulation and electrodynamic module. The module contains the sample under study, in the shape of dielectric resonator. The losses are detected after analysis of the time of resonator response to the high-frequency pulse.
France in the Middle Ages 987-1460 : from Hugh Capet to Joan of Arc
Translatora s Note. Foreword. List of Illustrations. List of Genealogical Tables. Part I: The Inheritance: . 1. The Empire. 2. The Frankish People. 3. The Principalities. 4. Disturbances. Part II: Lordship:. 5. The Village. 6. The Castle. 7. The Church. 8. King and Lord. Part III: Origins of State and Nation:. 9. The Great Age of Progress. 10. Louis VII. 11. Philip Augustus. 12. The South. 13. The Thirteenth Century. 14. The Fourteenth Century. 15. The Maid of Orleans. Epilogue. Chronology. Bibliography. Index.