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21.
Current-voltage characteristics of a system with a variable number of slipping phase centers resulting from phase separation
in a tin whisker under external microwave field with a frequency Ω/2π≅35–45 GHz have been studied experimentally. Emergence and disappearance of steps with zero slope in a whisker’s current-voltage
characteristic at U
m/n
=(m/n)U
Ω, where m and n are integers and U
Ω is determined by Josephson’s formula ℏΩ=2eU
Ω, have been investigated. Microwave field generated by slipping phase centers is nonharmonic, and the system of slipping phase
centers permits synchronization of internal oscillations at a microwave frequency by an external field with a frequency which
is the n-th harmonic of internal oscillations. The estimated microwave power generated by a whisker is 10−8 W. Stimulation of superconductivity in a current-carrying whisker has been detected.
Zh. éksp. Teor. Fiz. 113, 1364–1375 (April 1998) 相似文献
22.
23.
中药炮制过程化学机理研究 总被引:9,自引:0,他引:9
中药炮制是中国的一项传统制药技术,也是中药区别于天然药物的显著特点。中药材经过加工炮制以后发生了复杂的化学变化,随着这些化学变化而改变的物质基础是中药炮制前后性味、功能改变的重要原因。阐明中药炮制过程中发生的这些化学变化是中药炮制机理研究的主要内容。近年来,国内外很多研究机构对中药炮制过程的化学机理进行了深入研究,初步阐明了多味中药炮制过程中发生的化学反应及化学成分变化,主要的化学反应包括水解反应、氧化反应、置换反应、异构化反应和分解反应等。本文对近年来中药炮制过程中化学反应机理领域取得的研究成果进行了综述,并对中药炮制过程化学机理研究的方向及前景进行了探讨。 相似文献
24.
MV Muftakhov YV Vasil'ev VA Mazunov 《Rapid communications in mass spectrometry : RCM》1999,13(12):1104-1108
Appearance energies of [M-H](-) ions from carbonyl compounds R-CO-R' (R,R' = H, CH(3), NH(2), OH) have been measured by means of negative ion mass spectrometry in resonant electron capture mode. Values of electron affinity of the corresponding radicals, CH(2)&dbond;C(X)O, NH&dbond;C(X)O and O&dbond;C(X)O, have been determined. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
25.
V. L. Gurtovoi A. A. Burlakov A. V. Nikulov V. A. Tulin A. A. Firsov V. N. Antonov R. Davis S. Pelling 《Journal of Experimental and Theoretical Physics》2011,113(4):678-682
The states of two phase-coupled superconducting rings have been investigated. Multiple current states have been revealed in
the dependence of the critical current on the magnetic field. The performed calculations of the critical currents and energy
states in a magnetic field have made it possible to interpret the experiment as the measurement of energy states into which
the system comes with different probabilities because of the equilibrium and nonequilibrium noises upon the transition from
the resistive state to the superconducting state. 相似文献
26.
V. I. Yarygin V. N. Sidel’nikov I. I. Kasikov V. S. Mironov S. M. Tulin 《JETP Letters》2003,77(6):280-284
The results of experimental study of a condensate of cesium excited states (Rydberg matter) are presented. The possibility of condensate formation was predicted theoretically first by Prof. É.A. Manykin and coauthors from the Russian Research Center Kurchatov Institute and experimentally observed by L. Holmlid and coauthors from the Chalmers University, Sweden. In a thermionic energy converter with interelectrode medium, where, according to the data of Swedish researchers, Rydberg matter is formed, we observed similarities and distinctions between our and Swedish data on the formation of a condensate of cesium excited states. 相似文献
27.
Rong Xue Chang Deng Honghong Cao Kewei Zhang Tulin Lu Chunqin Mao 《Journal of separation science》2020,43(15):3017-3026
Aucklandia lappa Decne. has been used as a traditional Chinese herb for thousands of years in treating various kinds of disorders. According to the Chinese Pharmacopoeia, there are two kinds of processed products, raw and baked Aucklandia lappa Decne., which have different therapeutic effect in clinical application. In this study, based on color measurement and fingerprint analysis, the method to assess the quality of these two processed products was established. In color measurement, the reference ranges of color parameters (L*, a*, and b*), standard color difference values, and mathematical prediction functions of these two processed products were obtain after the color was measured by a spectrophotometer. Meanwhile, high‐performance liquid chromatography fingerprints of these two processed products were established, where there were 12 peaks recognized as the common peaks in both processed products, in which two peaks were identified as costunolide and dehydrocostus lactone, and these two processed products were classified with chemometrics analysis subsequently. Furthermore, the correlation between color parameters and sample compositions was explored and the contents of costunolide and dehydrocostus lactone were determined simultaneously by high‐performance liquid chromatography. Consequently, an integral method including color measurement, high‐performance liquid chromatography fingerprint with chemometrics analysis, and quantitative determination was established. 相似文献
28.
A. A. Burlakov V. L. Gurtovoĭ S. V. Dubonos A. V. Nikulov V. A. Tulin 《JETP Letters》2007,86(8):517-521
Little-Parks oscillations are observed in a system of 110 series-connected aluminum rings 2 μm in diameter with the use of measuring currents from 10 nA to 1 μA. The measurements show that the amplitude and character of oscillations are independent of the relation between the measuring current and the amplitude of the persistent current. By using asymmetric rings, it is demonstrated that the persistent current has a direction. This means that, in the Little-Parks experiment, the total current in one of the half-rings may be directed against the electric field. 相似文献
29.
Magnetic resonance and microwave impedance are studied in a highly doped La0.8Sr0.2MnO3 manganite near the Curie temperature. A splitting of the resonance line is observed in the temperature region 6° below the temperature corresponding to the maximum impedance at zero magnetic field. The microwave impedance exhibits a hysteretic behavior in increasing and decreasing temperature runs with jumps at the ends of a 2°-wide temperature interval. The splitting of magnetic resonance occurs immediately above the temperature corresponding to the impedance jump in zero magnetic field. The jumps and the hysteretic behavior of the impedance are interpreted as a manifestation of the magnetic structure phase transition of the first order. 相似文献
30.
Guy Indebetouw 《中国光学快报(英文版)》2009,(12)
Recent developments in scanning holographic microscopy that offer the prospects of new quantitative tools and imaging modalities in bio, micro, and nano sciences are reviewed. The versatility of the method is emphasized. Scanning holography can operate in an incoherent mode for fluorescence imaging, in a coherent mode for quantitative phase imaging, or in a tomographic mode for axial sectioning and rejection of the out-of-focus haze. Possible applications are illustrated with examples, and future prospects ... 相似文献