DIELECTRIC STUDIES OF UREASE AS A FUNCTION OF HYDRATION     

陆祖宏  Ronald Pethig  韦钰 《东南大学学报》1989,(2)

The steady-state electrical conductivity,as well as the dielectric propertiesbetween 2×10~(-4)Hz and 100 kHz,and at 1 GHz,are reported for urease compressed powdersamples of low hydration.The results show that the large,low frequency dielectricdispersion,known as α-dispersion,is due to the build-up of a space charge of protons atthe sample-electrode interfaces.A smaller dispersion,appearing at higher frequencies,isconcluded to be associated with hindered motions of the peptide residues in the molecularstructure of urease.The extent of these polypeptide backbone motions is shown to bestrongly depended on the extent of enzyme hydration.This work is contributed to the de-velopment of conductimetric biosensors.  相似文献   

外加因子的生物效应及其在生物技术中的应用     

李晓静  施秀芳  冯霞  阳葵 《安阳师范学院学报》2001,(2):10-12

本文讨论了生长调节剂、分散剂和超声波的生物效应以及它们在生物技术中的应用现状和前景．  相似文献   

Flat-top and low-dispersion optical interleavers based on nested prism pair structure     

张娟 《上海大学学报(英文版)》2011,15(1):31-34

A novel flat-top and low-dispersion optical interleaver using ring cavities (RCs) in a Mach-Zehnder interferometer (MZI) is proposed. It is composed of eight mirrors and two nested prism pairs. Each prism and the two mirrors behave as a RC. Phase shift of RC is a periodic function of the frequency of the input light which acts as a phase dispersive mirror. The two phase shifts needed to achieve a flat-top spectral passband are provided by Fresnel reffectivities at the prism-air interface of the two RCs. The...  相似文献   

Oseen流动中粘性对自由表面波的影响     

卢东强 《上海大学学报(英文版)》2004,8(1):8-12

Based on the complex dispersion relation for the two-dimensional free-surface waves generated by a moving body in the steady Oseen flows, the effect of viscosity on wavelength and wave amplitude was investigated by means of an asymptotic method and a numerical analysis. A comparison between the asymptotic and numerical analysis for the viscous decay factor demonstrates the validity of the perturbation expansions for the wave profile. The numerical result shows that the wavelength of viscous wave is slightly elongated in comparison with that of inviscid wave.  相似文献   

频散效应对铁磁共振曲线的影响     

王合英  孙文博  张慧云  茅卫红 《实验技术与管理》2007,24(11):28-30,42

在铁磁共振实验中，通过铁磁共振曲线测量共振线宽十分重要，因为它表示铁磁材料磁损耗的大小。频散效应对铁磁共振曲线有明显的影响，该文从理论上分析了频散效应的物理本质以及它对铁磁共振曲线的影响，阐述了测量共振线宽的具体实验方法。  相似文献   

催化剂研究中的分散阈值参数     

邓存 《江西教育学院学报》1997,18(3):25-28

分散阈值的大小与活性组分和载体相互作用有关，是催化剂研究中的一个重要实验参数，分散阈值的测定不仅为单层分散原理广泛的应用奠定了实验基础，亦为催化剂的研制提供一种定量研究手段  相似文献   

搜寻理论模型与网络搜寻行为探析   总被引：1，自引：0，他引：1  

叶小梁  李东旻 《情报科学》2006,24(11):1691-1695

本文从信息经济学的角度，从消费者搜寻模型、市场价格离散、消费者预期、搜寻成本等四个方面，针对消费者在购买商品时所进行的搜寻行为进行理论总结，并对该理论在网络搜寻行为等问题上的应用进行初步地探讨。  相似文献   

Study of resonance-cone propagation in truncated hyperbolic metamaterial grids using transmission-line matrix simulations     

Omar F. Siddiqui  George V. Eleftheriades 《Journal of The Franklin Institute》2011,348(7):1285-1297

In this paper, we utilize transmission-line matrix simulations to study the electromagnetic properties of hyperbolic metamaterial grids, which are synthesized by arranging unloaded transmission lines over electrical ground planes, such that the unit cells are rectangular in shape. The hyperbolic grids support Bragg and Hyperbolic resonant modes that have rectangular and hyperbolic dispersion surfaces, respectively. We demonstrate the formation of these resonant modes in the hyperbolic grids and their refraction, and spatial scanning properties via circuit simulations. The simulation results are compared with experimental results of a two-layer anisotropic hyperbolic metamaterial.  相似文献   

中国人力资本及其分布同经济增长的关系研究   总被引：1，自引：1，他引：0  

宋家乐  李秀敏 《中国软科学》2011,(5)

文章运用Park(2006)的方法和中国1952-2009年的数据,对人力资本及其分布同经济增长的关系进行了实证检验,结果表明,在控制追赶效应的前提下,中国人力资本水平的提高和人力资本分布的不平衡均对劳动生产率的提高起促进作用,而且,中国还处在库兹涅茨曲线的左边,即随着人力资本水平的提高,人力资本分布的不平衡程度也不断提高。因此,中国发展全民教育是合理的,不仅能够促进经济增长,还能改善收入分配。  相似文献   

管理层业绩预告与分析师盈余预测的相互影响：研究现状与启示     

纪新伟  宋云玲 《未来与发展》2011,34(8):56-61

统计模型以外,关于公司未来业绩的信息主要来自两个方面：管理层业绩预告和分析师盈余预测。现有研究发现,管理层可以通过业绩预告的发布时间、精度、准确度以及以往的预告声誉等因素影响分析师盈余预测;分析师则可以通过其对市场预期的影响力促使管理层及时披露准确的业绩预告。本文回顾了中美两国关于管理层和分析师互相影响的主要文献,指出了中国现有研究存在的差距,借以发现未来的研究机会。  相似文献