线形组合边界中煤层气井的不稳定压力数值分析

文章建立并求解了不同线性组合边界条件下的煤层气井不定常渗流模型,得到了井底压力和压力导数的理论曲线,以及压力场分布图.在不稳定流动的早期,压力和压力导数曲线都是斜率为1的直线段.当流体流动进入稳定流动状态时,在压力导数曲线上出现一个值为0.5的水平直线段.在理论曲线的晚期,理论曲线与边界性质存在密切关系.对于全封闭煤层气藏,所有压力和压力导数曲线是斜率为1的直线段.对于存在定压边界煤层气藏,压力双对数曲线的晚期是水平直线段,压力导数双对数曲线的晚期都是急剧下掉的曲线.但是混合边界的压力导数存在上翘现象,上翘程度和早晚与封闭边界的数目多少以及距离大小有关.压力场中,在靠近封闭边界的等压线垂直于边界,在靠近定压边界的等压线平行于边界.在邻近定压和封闭边界交合处,定压边界起主导作用.所得到的理论曲线可以直接应用于煤层气田的试井测试资料分析,压力场分布图对了解煤层气藏的开发状况有积极的意义.

纳米硬度计在MEMS力学检测中的应用

纳米硬度计是一种能提供103mm-10-2mm尺度材料或结构微力学性能检测的先进仪器。采用纳米压痕技术，研究薄膜材料的弹性模量和硬度随压痕深度的变化规律以及薄膜厚度测量，微桥弯曲变形测量的方法。采用纳米划痕技术，研究薄膜的表面粗糙度、临界附着力和摩擦系数测量的方法。该仪器能广泛应用于MEMS的力学检测，并有望成为这一领域内的标准力学检测设备。

Thermovibrational Instability Of Rayleigh-Marangoni-Benard Convection In Two-Layer Fluid Systems

The thermovibrational instability of Rayleigh-Marangoni-Benard convection in a two-layer system under the high-frequency vibration has been investigated by linear instability analysis in the present paper. General equations for the description of the convective flow and within this framework, the generalized Boussinesq approximation are formulated. These equations are dealt with using the averaging method. The theoretical analysis results show that the high-frequency thermovibrations can change the Marangoni-Benard convection instabilities as well as the oscillatory gaps of the Rayleigh-Marangoni-Benard convection in two-layer liquid systems. It is found that vertical high-frequency vibrations can delay convective instability of this system, and damp the convective flow down. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

Influence of threshold stress on the estimation of the Weibull statistics

The influence of threshold stress on the estimation of the Weibull statistics is discussed in terms of the Akaike information criterion. Numerical simulations show that, if sample data are limited in number and threshold stress is not too large, the two-parameter Weibull distribution is still a preferred choice. For example, the fit of strength data of glass and ceramics to the two- and three-parameter Weibull distributions is compared.

有关多层流体对流的研究

简述多层不相混流体系统的研究发展，尤其是在空间材料生长过程中的应用；介绍多层流体系统内流体对流及传热现象，以及利用理论分析、实验研究和数值模拟方法研究二层及三层流体内的自然对流及热毛细对流的成果，并分析探讨覆盖液体层对被覆盖液体的动力控制特性及其系统的稳定性。

Small-dynamic-angle measurement using tangent relationship and phase-modulating technique

A method using two prisms for measurement of small dynamic angles is proposed in which the measurement is based on a simple tangent equation and a phase-modulating interferometer with a laser diode to measure dynamic optical path differences with higher accuracy. Owing to the simple tangent equation, the symmetry requirement on the two prisms in the optical configuration is eliminated, and easy measurement of the separations between two parallel beams with a position-sensitive detector is achieved. Small-dynamic-angle measurements are experimentally demonstrated with high accuracy. (C) 2007 Society of Photo-Optical Instrumentation Engineers.

桂西那坡县种子植物区系初步研究

　　本文对桂西那坡县种子植物区系的成分进行了全面系统的的分析，以探讨区系的性质和特点，为研究广西植物区系和滇、越、桂植物区系提供宝贵的资料。 　　本区系有裸子植物9科、13属、17种，被植物164科、876属、2138种。科的分析表明以热带－亚热带分布居首位，次为热带分布。特征科有樟科、木兰科、壳斗科、金缕梅科、山茶科、茜草科、大戟科等共21科，它们也是我国热带、亚热带植物区系的特征科。 　　属的分析显示热带分布占70．75％，居首位;温带分布占18．6％;东亚分布占8．7％;我国特有分布占2．2％;缺乏中亚分布成分。热带分布中以印度－马来西亚成分居多，占27．6％，其次是泛带分布，占18．8％。 　　种的分析表明以中国特有分布居第一位，占45．1％;其次是热带亚洲分布，占31．6％;居第三位是东亚分布，占13．8％。 　　那坡植物区系特有现象十分显著，共计东亚特有科有8个，中国特有属有17个，中国特有种有774个，其中56种为那坡特有种。 　　分析结果表明那坡种了植物区系具有以下特征：（1）热带北缘性质，具有很强的热带向亚热带的过渡性;（2）特有现象显著;（3）岩溶特性明显;（4）地理成分复杂;（5）起源古老。 　　本区系分析所依据的植物名录由作者汇编而成，绝大部分种名有标本引证，且经专家审定，同时还溶进作者两次野外考察的心得，为到目前为止，最完整的一份该地区的植物名录。

THE POSSIBLE INVOLVEMENT OF TISSUE-TYPE PLASMINOGEN-ACTIVATOR IN LUTEOLYSIS OF RHESUS-MONKEY

Changes of plasminogen activators (PA) during different stages of development of the corpus luteum, and their possible physiological role in luteolysis were studied in rhesus monkeys. It was demonstrated for the first time that monkey corpus luteal cells not only produce PA, but that the function of the corpus luteum is also closely related to the activity of this enzyme system. Generally, the life span for a corpus luteum in monkey is approximately 14-16 days, its demise beginning thereafter. In the present study, we found that urokinase in the corpus luteum is higher on day 5 and day 10 after human chorionic gonadotrophin injection, while the tissue type (t) PA is mainly produced on day 13 when luteolysis may take place. Progesterone production remained high on day 5 and day 10 and decreased dramatically from day 13, indicating the important role of tPA but not urokinase (u) PA in suppressing luteal function. When purified tPA (but not uPA) monoclonal antibody was added to luteal cell culture to neutralize endogenously produced tPA activity, progesterone production in the cells was increased significantly. Interestingly, prolactin alone was capable of increasing PA production by luteal cells; prolactin together with luteinizing hormone, however, had a synergistic luteotrophic effect.

单细胞真核生物的miRNA系统及其进化意义

miRNA系统在高等多细胞真核生物中得到了广泛深入的研究。近年来,人们在单细胞真核生物上的miRNA研究也取得了重要进展。这不仅丰富了人们对miRNA在整个生物界中的认识,更重要的是对于揭示miRNA这一表达调节系统是如何在生物界中起源进化的问题具有重要意义。该文结合作者在最低等单细胞真核生物——贾第虫上的研究结果,对该领域的研究进展作一概述,并对有关miRNA这一系统的起源进化问题进行了探讨。

宁夏持续无虫灾防护林的结构设计

调查了宁夏新建二代防护林网主栽树种及辅栽乔、灌、草的生长表现和受害虫危害状况 ;列出了造林树种对主要害虫的抗性序列 ;将二代防护林网划分为 3个大类 ,每个大类又分为若干小类 ,并提出了各类防护林树种的选择。在以上研究的基础上提出无虫灾防护林树种的配置原则及设计方案。

An improved microtiter assay for evaluating anti-HIV-I neutralizing antibodies from sera or plasma

Background: The anti-HIV-1 neutralizing antibody assay is widely used in AIDS vaccine research and other experimental and clinical studies. The vital dye staining method applied in the detection of anti-HIV-1 neutralizing antibody has been used in many laboratories. However, the unknown factor(s) in sera or plasma affected cell growth and caused protection when the tested sera or plasma was continuously maintained in cell culture. In addition, the poor solubility of neutral red in medium (such as RPMI-1640) also limited the use of this assay. Methods: In this study, human T cell line C8166 was used as host cells, and 3-(4,5-Dimethyl-2-thiazolyl)- 2,5-diphenyl-2H-tetrazolium bromide (MTT) instead of neutral red was used as vital dye. In order to avoid the effect of the unknown factor( s), the tested sera or plasma was removed by a washout procedure after initial 3 - 6 h culture in the assay. Result: This new assay eliminated the effect of the tested sera or plasma on cell growth, improved the reliability of detection of anti-HIV-1 neutralizing antibody, and showed excellent agreement with the p24 antigen method. Conclusion: The results suggest that the improved assay is relatively simple, highly duplicable, cost-effective, and well reliable for evaluating anti-HIV-1 neutralizing antibodies from sera or plasma.

PFU微型生物群落采样法研究有机氯污染物在水中相间分布

运用PFU微型生物群落采样法在武汉东湖取样研究了六六六、滴滴涕、六氯苯等有机氯污染物在水中相间分布。将PFU(Polyurethanefoamunit)取样得到的挤出液 ,经细胞固定、超声、消解及分步萃取等不同的预处理步骤后 ,用GC ECD测定了各部分提取物中α HCH、β HCH、γ HCH、δ HCH、HCB、pp′ DDE等有机氯污染物的浓度。并用四膜虫模拟试验检验了细胞固定化、消解过程对微型生物的作用效果。结果分析表明 ,以上有机物主要以微型生物富集或颗粒物强吸附形式存在于水中 ,颗粒物弱吸附形

Annealing study of carrier concentration in gradient-doped GaAs/GaAlAs epilayers grown by molecular beam epitaxy

We measured the carrier concentration distribution of gradient-doped GaAs/GqAlAs epilayers grown by molecular beam epitaxy before and after annealing at 600 degrees C, using electrochemical capacitance voltage profiling, to investigate the internal variation of transmission-mode GaAs photocathodes arising from the annealing process. The results show that the carrier concentration increased after annealing. As a result, the total band-bending energy in the gradient-doped GaAs emission layer increased by 25.24% after annealing, which improves the pbotoexcited electron movement toward the surface. On the other hand, the annealing process resulted in a worse carrier concentration discrepancy between the GaAs and the GaAlAs, which causes a lower back interface potential barrier, decreasing the amount of high-energy photoelectrons. (C) 2009 Optical Society of America

协同环境中共有资源的细粒度协作访问控制策略

在军事和商业领域中,由多个自治域形成的协作群体对共有资源(如客体、应用程序以及服务等)的访问问题越来越受到重视.协作中的基本事实是:尽管这些自治域有共同的目标,但同时有不同的自身利益.为了有效地保护共有资源,把“信任”的概念引入了协作访问控制中,并在基于量化权限的思想上,提出了细粒度的协作访问控制策略.在该策略里,权限的使用形式是元权限,也就是单位权限,它是访问共有客体权限的一个划分,可为多个域中不同用户所拥有.当访问共有资源时,参与者们所拥有的元权限的值之和以及人数必须达到规定的权限门限值和人数值,并且访问时间是所有参与者的共同许可访问时间段,这使得可以对协作资源进行有效地分布控制.另外,还引入了元权限的使用时间段约束.最后,证明了该细粒度协作访问控制策略关于协作系统的状态转换是保持安全的.