Inhomogeneous Plane Symmetric String Cosmological Models in Bimetric Theory

It is shown that the inhomogeneous plane symmetric perfect fluid distribution and cosmic strings do not survive in frame work of bimetric theory of gravitation proposed by Rosen (Gen. Relativ. Gravit. 4:435, 1973). Hence vacuum models are presented and studied.     

Vibro-acoustic behaviour of laminated double glazing enclosing a viscothermal fluid cavity

This paper presents a new numerical model to investigate the vibro-acoustic behaviour of two laminated glass plates enclosing a thin viscothermal fluid cavity. The aim of this work is to develop an original five layer (two skins plies, two adhesive films and a core ply) laminated plate finite element by mixing Kirchhoff and Mindlin plate’s theory. The formulation is based on the theory that accounts for the transverse shear in the adhesive films and in the core. The acousto-elastic model is established in dimensionless appropriate form including the effects of viscosity and thermal conductivity of fluid and by taking into account the fluid-structure interaction. The discretization of the energy functional by finite element method gives after minimisation a symmetrical coupled matrix system in which the acoustic matrices are frequency dependent. Therefore, an iterative procedure is derived to determine the eigenmodes of the coupled system. The modal approach is adopted to determine the vibro-acoustic system’s response. Then, the validation of the new laminate finite element model is achieved by comparing the sandwich plate results against data obtained from literature. Subsequently, predicted responses, such as the vibration transmissibility and the transmission loss of the coupled system, for a given laminated double glazing under an imposed homogeneous pressure are presented and discussed. Numerical results show the importance of both lamination and viscothermal fluid effects on double glazing vibro-acoustic behaviour.     

Viscous Fluid Cosmology in Bianchi Type-I Space-Time

The paper presents a spatially homogeneous and anisotropic Bianchi type-I cosmological model consisting of a dissipative fluid. The field equations are solved explicitly by using a law of variation for mean Hubble parameter, which is related to average scale factor and yields a constant value for deceleration parameter. We find that the constant value of deceleration parameter describes the different phases of the evolution of universe. A barotropic equation of state (p=γ ρ) together with a linear relation between shear viscosity and expansion scalar, is assumed. It is found that the viscosity plays a key role in the process of the isotropization of the universe. The presence of viscous term does not change the fundamental nature of initial singularity. The thermodynamical properties of the solutions are studied and the entropy distribution is also given explicitly.     

流体PVT的对应关系

本文依据对应态原理,提出新定义的对比压缩因子Zr=(1-Z)/(1-ZC)的无量纲交换式和对饱和温度的对比温度Tsr=T/Ts式,并根据两种流体工质对比压力Pr1=Pr2,对比温度Tsr1=Tsr2相等时,Zr1=Zr2相等的原则,导出了从一种已知PVT关系的物质推算它种物质的PVT值的通用方法。用本方法以水为标准物质推算了R12、R131、R134a、C2H4等几种物质在过热气体区、超临界区和液体区比容,计算值与文献实验值的平均偏差小于2,最大偏差小于4%。     

同轴圆筒旋转黏度计测量原理详析

对同轴圆筒旋转黏度计的测量原理作了深入描述,对于理解旋转黏度计的构造原理以及测量条件,规范流体黏度的计量工作提供了帮助．     

低温气液两相流数值计算

低温工质两相流动在很多场合都存在,研究深冷剂在两相流动时参数的分布有着很重要的作用.文中采用一维均相流模型对液氮循环流动过程进行稳态数值模拟,得到了循环流动过程中液氮含汽率、压力和温度沿管程方向的分布情况,并对由于不同回路条件引起的不同结果进行了分析.     

超临界流体CO2萃取中药有效成分的抗氧化性的分光光度法研究

利用超临界流体二氧化碳萃取技术提取中药虎杖、大黄、炒白术中黄酮类化合物。在pH8．2的HCl—tris缓冲溶液中利用邻苯三酚自氧化法测定提取物对超氧阴离子自由基的消除作用。用茜素紫作显色剂的分光光度法在pH9．0的HCl—tris缓冲体系中测定中药提取物对Co^2 H2O2体系所产生的羟基自由基的消除作用,并对实验条件进行了探讨。实验结果表明,3种中药提取物对自由基都有消除作用,其中虎杖的效果最好。     

超临界流体萃取金属离子在环境分析上的应用

固体和液体中的金属离子能在含有有机螯合剂的超临界二氧化碳(SC-CO2)流体中被有效地萃取出来。超临界流体萃取(SFE)金属离子的效率取决于下列因素：螯合剂在SC-CO2中的稳定性和溶解性、金属络合物在SC-CO2中的溶解度、水、pH值、压力、温度及金属离子的化学形式和基质的性质等。     

体液中铝形态的HPLC分析

体液中铝浓度的升高能够导致严重的神经性疾病如阿尔茨海默症和帕金森氏症等。铝的毒性及生物效应与其存在形式有关,因此迫切需要建立可靠的分析体液中实际铝形态的方法。近十年来各种分离模式的HPLC在这方面使用最多。实验证明,血清中的铝主要与转铁蛋白(Tf)以AlN-Tf和AlN-Tf-Fec的方式结合,而余下的部分则与柠檬酸(Citrate)、磷酸(Phosphate)形成Al-citrate,Al-phosphate和Al-citrate-phosphate。     

Determination of acyclovir in horse plasma and body fluids by high-performance liquid chromatography combined with fluorescence detection and heated electrospray ionization tandem mass spectrometry

Two methods are presented for the determination of 'respectively' the plasma protein unbound and total concentration of acyclovir in horse plasma and body fluids: first, a liquid-liquid extraction was performed on plasma, combined with HPLC-fluorescence detection for the total plasma concentration; second a more sensitive method using high-performance liquid chromatography combined with heated electrospray ionization tandem mass spectrometry (LC-HESI-MS/MS) was described for plasma and for body fluids analysis. To obtain the unbound concentration of acyclovir in plasma, a simple deproteinization step using a Microcon filter was performed. Ganciclovir was used as an internal standard. Analysis was carried out on an Inertsil 5 ODS-3 column for the HPLC-fluorescence method. For the LC-HESI-MS/MS method a PLRP-S column was used. The limit of quantification (LOQ) for the total concentration was set at 50 and 2 ng mL(-1) for the HPLC-fluorescence method and the LC-HESI-MS/MS method, respectively. The limit of quantification for the unbound concentration was set at 5 ng mL(-1) and at 2 ng mL(-1) for body fluids. The methods were successfully used to perform pharmacokinetic and clinical studies in horses after intravenous and oral dosage of acyclovir and its prodrug valacyclovir.