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61.
62.
本文表明,利用两个特征值问题的规范变换,不仅可以建立和它们相联系的势的约束之间以及相应的有限维Hamilton系统间的变换关系式,而且可以由一个可积系统的对合守恒积分导出另一个系统的守恒积分  相似文献   
63.
R K Pandey  D N Tripathi 《Pramana》1992,39(6):589-595
Rescaled mean spherical approximation (RMSA) has been used to calculate the structure factor for the aqueous suspension of polystyrene macroions with the interaction potential taken according to Derjaguin and Landau (1941) and Verwey and Overbeek (1948) (DLVO) model. The effects of charge over the macroion and size on the surface potential and therefore, the structure factor have been studied. The breakdown of the DLVO potential with an excess charge over the macroion (⩾800e) has been reported. The oscillation in the first peak height of structure factor versus wave vector curve with size has been correlated with the Debye length.  相似文献   
64.
65.
用光锥QCD求和规则研究D→Klv~l衰变过程,首先计算D→K跃迁形状因子,通过构造新的关联函数,消除了twist-3波函数的不确定性给计算结果所带来的影响,从而使计算结果更加精确. 计算得到的分支比与最近的实验数据相一致. 关键词: QCD光锥求和规则 D介子半轻衰变 分支比 形状因子  相似文献   
66.
In the present work, for the first time, heterojunction has been fabricated using electrochemically deposited isotype p-selenium-p-polyaniline from a single solution bath. The structural characterization of selenium and polyaniline thin film was carried out using XRD technique. Polyaniline exhibited amorphous structure while selenium offered monoclinic (β) phase. The junction was formed by electrodepositing polyaniline over selenium film and heating at 423 K. The current density versus voltage (J-V) plot showed the formation of a junction with ideality factor of 1.16. From J-V characteristics at different temperatures, static resistance (Rs), dynamic resistance (Rd), and rectification ratio of diodes were determined. Heat treatment above 448 K caused junction breakdown.  相似文献   
67.
We study low regularity solutions of the Chern-Simons-Higgs equations. The Lorentz gauge condition makes them hyperbolic equations with the null form. Under the Coulomb gauge condition they are formulated in the hyperbolic equation coupled with elliptic equation. The div-curl decomposition is used in the temporal gauge.  相似文献   
68.
The polypyrrole/p‐InP structure has been fabricated by the electrochemical polymerization of the organic polypyrrole onto the p‐InP substrate. The current–voltage (I–V), capacitance–voltage (C–V), and capacitance–frequency (C–f) characteristics of the PPy/p‐InP structure have been determined at room temperature. The structure showed nonideal I–V behavior with the ideality factor and the barrier height 1.48 and 0.69 eV respectively. C–f measurements of the structure have been carried out using the Schottky capacitance spectroscopy technique and it has been seen that there is a good agreement between the experimental and theoretical values. Also, it has been seen that capacitance almost show a plateau up to a certain value of frequency, after which, the capacitance decreases. The higher values of capacitance at low frequencies were attributed to the excess capacitance resulting from the interface states in equilibrium with the p‐InP that can follow the a.c. signal. The interface state density Nss and relaxation time τ of the structure were determined from C–f characteristics. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1572–1579, 2006  相似文献   
69.
Both homogeneous and asymmetric polyethersulfone (PES) membranes were prepared by solvent casting. The sorption and permeation behavior of CO2, O2, and N2 using these two kinds of cast PES membranes and commercially available homogeneous PES film was investigated to extract the pressure dependence of gas permeability and the permselectivity for CO2 relative to N2, and to confirm the validity of the working assumption that a skin layer in an asymmetric membrane can be essentially replaced by a thick homogeneous dense membrane. The pressure dependence of the mean permeability coefficient to CO2 in homogeneous membranes obeys the dual-mode mobility model. The ideal separation factor for CO2 relative to N2 at an upstream pressure of 0.5 MPa attains ca. 40, while the permeability to CO2 is about 2.7 Barrer at the same upstream pressure. The same separation factor in asymmetric membranes amounts to 35. The diffusion behavior for the skin layer in an asymmetric membrane with a thin skin layer can be simulated approximately by that in a homogeneous dense membrane. © 1993 John Wiley & Sons, Inc.  相似文献   
70.
介绍铌材超导腔的研制进展,重点讨论了国产铌腔的材料改性,以及相应的超导腔性能的改进.叙述了1.5GHz铌腔的腔形设计,分析了铌材的射频性能和机械性能,制定了铌腔制作与后处理的特定工艺.最后给出了1.5GHz铌材超导腔的低温实验结果.  相似文献   
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