Synthesis and characterization of an interpenetrating polymer network composed of poly(methacrylic acid) and poly(vinyl alcohol)

Temperature and pH‐responsive interpenetrating polymer network (IPN) hydrogels, constructed with poly(methacrylic acid) (PMAA) and poly(vinyl alcohol) (PVA), by a sequential IPN method, were studied. The characterization of IPN hydrogels was investigated by Fourier‐transform infrared spectroscopy, differential scanning calorimetry (DSC) and swelling under various conditions. The IPN hydrogels exhibited relatively high swelling ratios, in the range 230–380 %, at 25 °C. The swelling ratios of the PMAA/PVA IPN hydrogels were pH and temperature dependent. DSC was used for the quantitative determination of the amounts of freezing and non‐freezing water. The amount of free water increased with increasing PMAA content in the IPN hydrogels. Copyright © 2004 Society of Chemical Industry     

Colour Centres and Energy Transfer in BaF2-xClx:Eu2+ Phosphors

The optical absorption spectra of BaF2-xClx:Eu2 after ultraviolet (UV) light excitation were investigated.The differences between the absorption spectra after and before excitation (DAS) were observed.The DAS increase at both the high and the low energy side of F band in BaF2-xClx:Eu2 after 245 nm UV light excitation.The bleach effect of UV light and the absorption of electrons in the valence band may account for the former and the formation of Fa centres (association of F(Cl-) centres), whose absorption band matches the HeNe laser better, may explain the latter.In the write-in process, the transfer of electrons is via tunneling.In the readout process, the transfer of electrons captured in F(F-) and Fa centres is more likely via tunneling, and that of F(Cl-) centres is more likely via conduction band.     

在LabVIEW程序运行中实现控件的动态移动

通过两种在LabVIEW程序运行中实现控件移动的方法的对比,着重介绍了结合了VI Sever技术的动态注册事件结构的用法,从而总结出其具有优化程序、减少内存、提高CPU利用率等方面的优点.     

软β核素内部样品塑料闪烁探测器

本文评价了塑料闪烁片用作软β核素探测器时的计数效率、β谱、本底谱和康普顿电子谱的特征。文中强调:采用胶合光导剂构成的系统是一种新型探测器(软β核素内部样品塑料闪烁探测器)。本文提出内部样品固体探测器、胶合光导剂和胶合闪烁光导剂的新概念。     

地震勘探技术在焉耆盆地勘探开发中的合理应用探讨

地震勘探技术应用可以分为以二维地震研究构造为主的地震勘探初级阶段、以地震地层学为主的地震勘探中级阶段、以三维地震油藏静态描述为主的地震勘探高级阶段、以地震储层研究为主的开发地震妆级阶段和以四维地震进行油藏监测为主的开发地震高级阶段。针对5个不同阶段的地质条件和地质任务，选择使用合理的地震勘探技术是有效提高勘探开发效益的重要途径。焉耆盆地的勘探开发体现了以地震勘探为主的思路，在勘探开发过程中重视了针对不同勘探开发阶段和不同的地质 地震技术，因此，在早期勘探开发中取得了很好的经济效益。     

Effects of Ca and Zr substitution upon structure and properties of Ba5LaTi3Ta7O30 low-loss dielectric ceramics

Effects of Ca and Zr substitution upon the dielectric properties of Ba₅LaTi₃Ta₇O₃₀ ceramics were investigated together with the structural characterization. All the samples of Ba₅La(Zr_xTi_1−x)₃Ta₇O₃₀ formed a filled tungsten-bronze structures, whereas the solid solution limit was determined as x=0.25 in (Ca_xBa_1−x)₅LaTi₃Ta₇O₃₀. Beyond this limit secondary phase of CaTa₂O₆ was detected and it would become the major phase for the Ca-rich compositions. The temperature coefficient of dielectric constant was improved with increasing Zr content while the dielectric constant decreased and the low dielectric loss varied little (in the order of 10⁻⁴). In the case of (Ca_xBa_1−x)₅LaTi₃Ta₇O₃₀, small temperature coefficient of dielectric constant could be obtained with increasing Ca content while the dielectric constant decreased significantly, and a small amount substitution of Ca for Ba induced decrease in dielectric loss.     

Adhesive element modelling and weighted static shape control of composite plates with piezoelectric actuator patches

A novel finite element model is presented for static and dynamic analysis of composite plates integrated with a laminated piezoelectric layer, a host laminated composite plate and an adhesive layer between them. A new adhesive element is developed which includes both peel and shear effects in the adhesive layer based on first‐order shear deformation plate theory. The thin adhesive layer between the piezoelectric layer and the host plate is modelled by assuming that it carries constant shear and peel strains throughout its thickness. In addition, a weighted static shape control scheme for finding the optimal voltage distribution for static shape control is given. By selecting different weighting matrices, a variety of items such as displacements, slopes, curvatures, strains and even generalized forces, can be included in finding the optimal actuating voltage for static shape control. The present model is validated by comparing with those results available in the literature. The numerical results show that the weighted linear least method can give a satisfactory voltage distribution to best match the desired shape. Copyright © 2004 John Wiley & Sons, Ltd.     

激光熔覆前合金粉末的火焰喷涂

火焰喷涂是激光熔覆前合金粉末的预置方法之一。本文在实验的基础上,探讨了工艺过程,并讨论了影响质量的因素。