The influence of temperature, pressure, salinity and capillary force on the formation of methane hydrate

We present here a thermodynamic model for predicting multi-phase equilibrium of methane hydrate liquid and vapor phases under conditions of different temperature, pressure, salinity and pore sizes. The model is based on the 1959 van der Waals-Platteeuw model, angle-dependent ab initio inter- molecular potentials, the DMW-92 equation of state and Pitzer theory. Comparison with all available experimental data shows that this model can accurately predict the effects of temperature, pressure, salinity and capillary radius on the formation and dissociation of methane hydrate. Online calculations of the p-T conditions for the formation of methane hydrate at given salinities and pore sizes of sediments are available on: www.geochem-model.org/models.htm.     

Transfection of glutathione S-transferase (GST)-pi antisense complementary DNA increases the sensitivity of a colon cancer cell line to adriamycin, cisplatin, melphalan, and etoposide

The goal of this study was to demonstrate that glutathione S-transferase (GST)-pi is directly involved in the intrinsic and acquired resistance of cancer cells to anticancer drugs. To this end, GST-pi antisense cDNA was transfected into the cultured human colon cancer cell line M7609, which expresses an innately high level of GST-pi and shows intrinsic drug resistance, and into an M7609 strain with acquired resistance to Adriamycin (ADR;i.e., M7609/ADR cells). The changes in the sensitivity of these transfectants to various anticancer drugs were investigated. The intracellular concentrations of GST-pi in M7609/anti-1 cells and M7609/anti-2 cells, two clones that were established by transfection of GST-pi antisense cDNA into M7609 cells, were decreased to approximately half of those detected in the parent cells (M7609) and in the control cells transfected with vector alone (M7609/pLJ). The sensitivities of the antisense transfectants in relation to ADR, cisplatin, melphalan, and etoposide were increased -3.3-fold, 2.3-fold, 2.2-fold, and 2.1-fold, respectively, compared with those of M7609 and M7609/pLJ. On the other hand, the sensitivities of the antisense transfectants to Taxol, vincristine, 5-fluorouracil, and mitomycin C were not significantly changed. Similarly, the transfection of antisense cDNA into M7609/ADR cells resulted in the reduction of intracellular GST-pi concentration (by about half) and an increased sensitivity to ADR (4.4-fold), but no increase in 5-fluorouracil sensitivity. Thus, GST-pi is considered to be a multidrug resistance factor that is responsible for both the intrinsic and acquired resistance of cancer cells to anticancer drugs such as ADR, cisplatin, melphalan, and etoposide.     

Molecular pharmacology of voltage-dependent calcium channels

Voltage-dependent Ca2+ channels serve as the only link to transduce membrane depolarization into cellular Ca(2+)-dependent reactions. A wide variety of chemical substances that have the ability to modulate Ca2+ channels have been demonstrated both for their clinic utility and for importance in elucidating the molecular basis of various biological responses. Recently, introduction of molecular biology to pharmacology has brought a great deal of information about the molecular basis of drug action in Ca2+ channels. In this review, we attempt to overview recent progress in understanding the interactions between Ca2+ channels and their blockers, namely Ca2+ antagonists, from a molecular and structural point of view.     

PECVD SiN 应力特性的研究

用自制的激光束偏转法测量衬底形变弯曲系统,测量了等离子增强化学汽相淀积(PECVD)SiN 膜的应力,反应气体为硅烷和氮气,结果表明:SiN 的应力为压应力,介于1～3×10~9N/m~2,应力的大小依赖工艺条件,如淀积温度、气体组分等,SiN 的本征应力也是压应力,数值为1.1×10~9N/m~2,最后,建立了用于解释本征应力的定性模型——等效晶粒模型,成功地说明了 SiN 膜的应力形成。     

抗战胜利后的蒋日伪合流评析

抗战胜利后，代表中国两种命运、两个前途的斗争日益尖锐。以蒋介石为首的重庆国民政府开始以与日伪合流的方式对抗在抗战中发展壮大的人民力量。蒋日伪合流的前提和基点是反共，希图借此来网络各种反动势力，扼杀中国的进步力量，并为将来发动反革命内战做准备。蒋日伪合流的出现不是偶然的，它是在特定历史条件下的产物，背后有着深刻的阶级动因在起作用。蒋日伪合流丑剧最终以可耻的失败退出了历史舞台。     

制订城市抗震加固投资分配政策的最优化方法

城市的抗震防灾工作是一项重要而复杂的系统工程。本文利用一种动态最优化方法,初步解决了城市抗震加固投资的分配问题。该方法具有简便、实用的特点,可以较好地揭示城市抗震加固工作的经济本质和内在机制。该方法的应用可以取得显著的经济效益。     

e-Automation,an architecture for distributed industrial automation systems

Due to the complexity of modern industrial systems, a conventional automation system is not capable of providing sufficient information management and high-level intelligent approaches, as achieving these functionalities requires the support of comprehensive data management and coordination between system devices and heterogenous information. This paper proposes the concept of e-Automation, in which computer networking and distributed intelligence agent technologies are applied to industrial automation systems, and presents a hardware and software architecture that implements this concept. An open infrastructure based on multi-agent systems is employed in the proposed architecture of e-Automation, which aims to allow the implementation of diverse tasks and to permit greater configurability than can be obtained from a traditional system. To evaluate our proposed e-Automation concept, this paper presents a case study of substation information management which adopts the proposed e-Automation architecture in power system domain.     

二维三氧化钨纳米结构的合成及其在光电探测器中的应用

三氧化钨（WO₃）是制造晶体管和光电探测器的理想材料,虽然在WO₃纳米结构的生长方面已经完成了一些工作,但是制造足够长的理想型纳米线仍然是一个挑战。在众多的合成方法中,作者选择了化学气相沉积（CVD）方法合成WO₃纳米线,并对其在光电传感器中的应用进行了研究。影响WO₃纳米线成品率的主要因素是前体材料温度、基片位置、载气流速和生长持续时间。在合适的生长条件下生长的纳米线长度最长约为100 μm。这些WO₃纳米线可用来制造高性能的光电探测器,WO₃光电探测器具有灵敏度高、响应速度快、模块微型化等优良的器件性能,表明二维WO₃纳米线在光电探测器的制造中具有很大的优势。      

虚拟现实的发展及在机器人系统中的应用与研究

本文全面回顾了虚拟现实技术的发展,及其在机器 人领域的应用与研究;分析了目前所面临的问题及主要研究方向．     

Two-Parameter Thermal Lattice BGK Model with a Controllable Prandtl Number

In this paper, two time relaxation parameters are introduce to a thermal lattice BGK, model to make its Prandtl number controllable. The dependency of the Prandtl number on the two parameters is derived. Numerical measurement of the transport coefficients is used to demonstrate the validity of the method. Furthermore, two examples of convective heat transfer are calculated, with one to show the effectiveness, and the other to show the breakdown of the two-parameter formulation under different conditions.