光学双稳性临界点的相变行为

本文详细地讨论了光学双稳性(OB)的临界现象。理论分析主要以忽略量子涨落的Fokker-Plank方程的静态解为基础。结果发现,OB的临界现象可以纳入Landau二级相变理论的框架,并且有关临界指数之间的关系也服从标度律。 关键词：     

Equilibrium CH-acidities of dimethyl 2-dimethoxyphosphoryl malonate and its thiophosphoryl analog

The pK _a values of dimethyl 2-dimethoxyphosphoryl malonate and of its thiophosphoryl analog have been measured by transmetallation using the inclusion complex of Li⁺ with [2.1.1]-cryptand as the metallation agent.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 410–411, February, 1993.     

The preparation and properties of “porous silicon–nickel ferrite” nanoheterocomposites for gas detectors

This paper discusses the preparation and properties of gas detectors based on “porous silicon–nickel ferrite” nanocomposites. Impedance spectroscopy was used to measure sensitivity to ethanol and isopropanol vapours in the presence of an alternating electric field. The results were interpreted with the help of an equivalent electrical circuit. In the analysis of the resistive–capacitive properties in the equivalent circuit a constant phase element was used.     

Aggregate stability and magnetic characteristics of colloidal Fe m O n –SiO2 particles obtained by sol–gel method

Physics of the Solid State - Composite Fe m O n –SiO2 particles have been obtained by precipitation of iron oxide from aqueous solution with the addition of tetraethoxysilane. The shapes and...     

氮氧自由基研究XVII:水溶液中哌啶氮氧自由基的电化学行为和自衰变动力学研究

循环伏安法研究表明,2,2,6,6-四甲基-4-羟基哌啶-1-氧自由基和2,2,6,6-四甲基-4-氧哌啶-1-氧自由基,在水溶液中的单电子氧化电极反应的可逆性随介质酸性,扫描速度和自由基浓度增加而增加,表明电极氧化产物可进一步发生化学反应.     

指向学习体验的物质及其转化复习的教学实践——以“钠及其化合物”为例

学习体验是学生对学习内容、过程、方法、意义的自我感受和评估,对学生学习志趣、学习素养提升有积极正向作用。以钠及其化合物复习为例,将各类别物质间转化关系的构建、物质制备原理和条件的优选作为学习体验对象,依据学习体验的内在发展历程设计学习任务及活动,引导学生亲身体验学科认知方式、学科思维方法、学科应用价值,评价体验结果,激励学生自主学习发生。     

Charge Transport and Magnetotransport Properties of Polyimide Irradiated by 80keV Co Ions

Charge transport properties of polyimide films implanted with 80 keV Co ions at two different fluences （series I： 1.25 × 10^17 ions/cm^2, series Ⅱ： 1.75 × 10^17 ions/cm^2） are studied in detail. For series I, the temperature dependence of surface resistivity fits Mott＇s equation very well. It is on the insulating side of the insulator-metal transition （IMT）. However, for series Ⅱ, the temperature dependence of surface resistivity is not in agreement with Mott＇s equation. It is on the metallic side of lMT. The magnetotransport properties of these two series are also studied. No significant magnetoresistive effect is observed for series I at both 5 K and 300 K. For series Ⅱ, an obvious magnetoresistive effect is observed at 5 K, while there is no magnetoresistive effect at 300 K. Rutherford backscattering spectrometry （RBS） is applied to confirm the actual fluence for these two series.     

Synthesis and some properties of 2,2,2-trimethoxy-3-isopropyl-4-bromo-5-oxo-1, 5,2 -oxazaphosphol-4-ene

Conclusions 2,2,2-Trimethoxy-3-isopropyl-4-bromo-5-oxo-1,5,2-oxazaphosphol-4-ene was isolated when trimethyl phosphite is reacted with 1-bromo-1-nitro-3-methyl-1-butene, and some of its transformations were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 462–465, February, 1978.The authors wish to thank É. I. Gol'dfarb for taking the³¹P-¹H} NMDR spectra.