Bianchi type-V cosmological model with perfect fluid using negative constant deceleration parameter in a scalar tensor theory based on Lyra Manifold

An exact Bianchi type-V perfect fluid cosmological model is obtained in a scalar tensor theory proposed by Sen (Z. Phys. 149:311, 1957) based on Lyra Manifold in case of β is a constant and it is shown that this cosmological model exists only in the case of Radiation Universe (ρ=3p) if β is a function of ‘t’ using negative constant deceleration parameter. Some physical and geometrical properties of these models are discussed.     

基于钻井液流变性的涡轮钻具性能预测研究

为探究钻井液流变性变化对涡轮钻具性能的影响,针对Ф89 mm取心涡轮钻具涡轮级进行叶片建模,采用CFX进行不同钻井液性质下的多级涡轮仿真。流场及数值模拟结果表明：随着钻井液粘度增加,涡轮级的转矩呈对数增长、压降增大,效率降低,钻井液在涡轮级的出口速度减小;而钻井液密度的增加增大了其在涡轮定转子中的流速及压降,同时涡轮效率有所提高。结果为优化涡轮叶片的设计提供依据;现场使用涡轮钻具,也应考虑其对钻井液流变性变化的适应能力,及时调整泵压、钻压保证最佳工况。     

压裂液黏度对循环水力压裂影响的试验研究

中国石油大学（北京）石油天然气工程学院,北京 102249     

拉梅常数反演在四维地震监测中的应用

在4D地震监测中,储层特性的变化主要是通过拉梅常数的变化才最终表现为地层速度和实际地震响应的变化,因此,在一定条件下,拉梅常数应当是储层特定变化最直接和灵敏的标志。本文详细叙述了拉梅常数反演的方法,并将其应用于实际4D地震资料的反演和解释中。良好的反演结果表明拉梅常数反演用于4D地震监测是切实可行的。     

酸碱滴定中精确计算pH值的通式及求解

本文介绍一个适合于任何滴定体系中的精确计算氢离子浓度的通式,它涉及到三次、四次或五次方程的求解。借助于程序计算器或计算机,求解出方程能满足题意的唯一实根并不困难。将它存入计算机,绘制滴定曲线或计算溶液的pH值就更方便了。     

Viscosity of sea surface microlayer in Jiaozhou Bay and adjacent sea area

This study on the temporal and spatial variability of the viscosity and some chemical parameters in the sea surface microlayer (SML), the relationship between the viscosity and chemical parameters, and the influence of the viscosity on the mass transfer coefficient (K) in the flux of materials through the air-sea interface revealed that: The values of viscosity and some chemical parameters in the SML are higher than those in the sub-surface layer (SSL), and at daytime are higher than those at night. The viscosity has positive corelation with chemical oxygen demand (COD),dissolved organic carbon (DOC) and salinity. The “SML effect“ on K need not be considered because the SML effect on materials concentration is so small.     

Comparison between two methods of modelling the flow in a mantle with laterally variable viscosity

Summary Two different spectral methods have recently been used to model the flow driven by harmonic loads in a Newtonian mantle with laterally variable viscosity. The first method, by Zhang and Christensen (1993), transforms the problem with a general three-dimensional viscosity into a series of standard spherically symmetric problems. A different approach has been chosen by Martinec et al. (1993). Their method is based on integral formulation of the problem. The solution, which corresponds to a minimum of the dissipative energy, is found by means of the gradient search. We have tested the efficiency and numerical behaviour of both methods. The results of our tests favour the former method which is found more accurate and significantly faster than the gradient algorithm.     

微分电位溶出分析测定配合物稳定常数的研究

报道用微分电位溶出分析法测定配合物在玻炭电极上氧化溶出电位与配位体浓度之间的关系，研究配合物的逐级稳定常数和参与形成配合物的配位体数目。研究了Ｃｕ（Ｈ２Ｓａｌ）２＋２和Ｃｄ（ＳＣＮ）２－４配合物体系，测定结果与文献［３，４］报道结果基本吻合     

Late Quaternary sediment dating and quantification of lateral sediment redistribution applying230Thex: a study from the eastern Atlantic sector of the Southern Ocean

High-resolution records of the natural radionuclide²³⁰Th were measured in sediments from the eastern Atlantic sector of the Antarctic circumpolar current to obtain a detailed reconstruction of the sedimentation history of this key area for global climate change during the late Quaternary. High-resolution dating rests on the assumption that the²³⁰Th_ex flux to the sediments is constant. Short periods of drastically increased sediment accumulation rates (up to a factor of 8) were determined in the sediments of the Antarctic zone during the climate optima at the beginning of the Holocene and the isotope stage 5e. By comparing expected and measured accumulation rate of²³⁰Th_ex, lateral sediment redistribution was quantified and vertical particle rain rates originating from the surface water above were calculated. We show that lateral contributions locally were up to 6.5 times higher than the vertical particle rain rates. At other locations only 15% of the expected vertical particle rain rate were deposited.