中原高温高盐油藏疏水缔合聚合物凝胶调剖剂研究

针对中原油田高温(>80℃)、高盐度(>50 g/L)、高硬度(>1 g/L)砂岩油藏,研制了地下成胶的高热稳定性聚合物凝胶调剖剂。所用聚合物为疏水缔合聚合物AP-P4,M=9.0×106,HD=27%,疏水基摩尔分数0.2%;交联剂为可生成酚醛树脂的3种化合物;调剖剂胶液用矿化度160 g/L的马寨油田污水配制;实验温度95℃。根据形成的凝胶黏度(95℃,1.1 s-1)确定交联剂各组分用量为:MZ-YL 0.429%,MZ-BE 0.060%,MZ-XS 0.012%;酸度调整剂用量0.12%;成胶时间10~15小时。2.5、3.0、3.5 g/L AP-P4的凝胶在95℃老化100天后黏度保持在~40 Pa.s及以上。初配制胶液在3000 r/min下剪切15分钟后黏度降低87.5%~89.0%,但成胶后和老化过程中凝胶黏度只比未剪切样降低17.1%~6.6%。3.5 g/L AP-P4的调剖剂对~1μm2的6支储层岩心的堵塞率在88.1%~95.8%范围,平均93.3%,造成的残余阻力系数在15.2~28.6范围,平均19.8,使渗透率级差2.3~8.0的4组双人造岩心的注水流量比发生不同程度的反转。认为该凝胶调剖剂高温下稳定性好的原因,是强化学交联密度低,因而凝胶脱水收缩作用弱。图2表5参5。     

房地产中介服务业存在的问题和改进建议

本文就房地产中介服务业在政府机构管理、行业经营方面存在的问题进行了总结,同时提出一些改进建议,对于房地产中介服务业规范经营、健康发展具有很好的指导意义。     

光谱法快速测定土壤中的多个微量元素

本法采用碳酸钡、氟化锂、石墨粉作缓冲剂，用锑做铅锌的标．用铪作铌的内标，用钯作铍、铬、镧、锶、铜的内标。采用小孔电极，交流电弧做为激发光源，同时测定铅、锡、锌、铍、铬、镧、铌、铜、锶等九个元素。分析数据基本稳定．能达到土壤样品的检出限要求。     

Stateful session handoff for mobile WWW

This paper proposes a web session handoff system that can hand over not only stateless but also stateful sessions between homogenous and heterogeneous user devices to enable uninterrupted and seamless web access. The proposed system adopts a proxy-based approach and an optional client-assisted scheme in order to track and hand over session information. In the proposed system, a session is registered at a User Agent Proxy (UAP) and then tracked by the UAP so that the session can be handed over from one device via the UAP to another device. In addition to session information tracked by a UAP, the UAP can hand over more comprehensive session information by using the client-assisted scheme. Compared with client-based approaches, our design has several advantages, such as less modification to user devices, practicability, and fault tolerance. We have implemented a UAP on a PC and client programs for both PC and PDA. The implementation can successfully hand over between PC and PDA a stateful session for online shopping applications.     

Kinetic study of the decompositions involved in the thermal degradation of commercial azodicarbonamide

The transitions and reactions involved in the thermal treatment of several commercial azodicarbonamides (ADC) in an inert atmosphere have been studied by dynamic thermogravimetry analysis (TGA), mass spectrometry and Fourier transform infrared (FTIR) spectroscopy. A pseudo‐mechanistic model, involving several competitive and non‐competitive reactions, has been suggested and applied to the correlation of the weight loss data. The model applied is capable of accurately representing the different processes involved, and can be of great interest in the understanding and quantification of such phenomena, including the simulation of the instantaneous amount of gases evolved in a foaming process. In addition, a brief discussion on the methodology related to the mathematical modeling of TGA data is presented, taking into account the complex thermal behaviour of the ADC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Protecting mobile agents＇ data using trusted computing technology

Even with attractive computational advantages, mobile agent technology has not developed its full potential due to various security issues. This paper proposes a method called Private Key Consignment to solve the problem of how to protect the data carried by mobile agents. It exploits new functionalities and mechanism provided by the trusted computing technology, and adopts both public key and symmetric key cryptographic means for data and key protection. The most notable feature of this method is that it protects the private key of the agent by consigning it to a tamper proof hardware, thus, enabling convenient and secure use of the private key. It provides a new scheme of mobile agents＇ data protection.     

Using Automated Negotiation for Grid Services

The popularity of grid services has widened their application to numerous domains and increased the utilization of computational resources. In order to create more incentives for the resources owners to lease their resources and prevent users from wasting the resources, the introduction of a market-oriented grid is inevitable. However, the issues for the negotiation between service provider and consumer over the supply and demand of resources can be complex, with highly interdependent issues. In this research, a simulated automated negotiation mechanism including a co-evolutionary mechanism and a modified game theory approach is proposed, to assist them in reaching an agreement over the conflicting issues. In the proposed architecture, the co-evolution process is able to reduce the multiple dimensional search space into a two-dimension search space and identify the appropriate negotiation strategies for the negotiating agents to form a payoff matrix which can be used for the game theory related stage of their interaction. The multiple stage negotiation process is introduced to improve the negotiation result. In this paper, an application which requires a large amount of computational resources to process the data generated from mobile devises is used to demonstrate that the proposed system is able to resolve the conflicts and obtain a valid solution.     

Verifiable Distributed Oblivious Transfer and Mobile Agent Security

The mobile agent is a fundamental building block of the mobile computing paradigm. In mobile agent security, oblivious transfer (OT) from a trusted party can be used to protect the agent’s privacy and the hosts’ privacy. In this paper, we introduce a new cryptographic primitive called Verifiable Distributed Oblivious Transfer (VDOT), which allows us to replace a single trusted party with a group of threshold trusted servers. The design of VDOT uses a novel technique called consistency verification of encrypted secret shares. VDOT protects the privacy of both the sender and the receiver against malicious attacks of the servers. We also show the design of a system to apply VDOT to protect the privacy of mobile agents. Our design partitions an agent into the general portion and the security-sensitive portion. We also implement the key components of our system. As far as we know, this is the first effort to implement a system that protects the privacy of mobile agents. Our preliminary evaluation shows that protecting mobile agents not only is possible, but also can be implemented efficiently. This work was supported in part by the DoD University Research Initiative (URI) program administered by the Office of Naval Research under grant N00014-01-1-0795. Sheng Zhong was supported by ONR grant N00014-01-1-0795 and NSF grants ANI-0207399 and CCR-TC-0208972. Yang Richard Yang was supported in part by NSF grant ANI-0207399. A preliminary version of this paper was presented at the DialM-POMC Joint Workshop on Foundations of Mobile Computing in 2003. Sheng Zhong received his Ph.D. in computer science from Yale University in the year of 2004. He holds an assistant professor position at SUNY Buffalo and is currently on leave for postdoctoral research at the Center for Discrete Mathematics and Theoretical Computer Science (DIMACS). His research interests, on the practical side, are security and incentives in data mining, databases, and wireless networks. On the theoretical side, he is interested in cryptography and game theory. Yang Richard Yang is an Assistant Professor of Computer Science at Yale University. His research interests include computer networks, mobile computing, wireless networking, sensor networks, and network security. He leads the LAboratory of Networked Systems (LANS) at Yale. His recent awards include a Schlumberger Fellowship and a CAREER Award from the National Science Foundation. He received his B.E. degree from Tsinghua University (1993), and his M.S. and Ph.D. degrees from the University of Texas at Austin (1998 and 2001).     

Accelerator Analysis of Tributyltin Adsorbed onto the Surface of a Tributyltin Resistant Marine Pseudoalteromonas sp. Cell

Tributyltin (TBT) released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (10^{9.3 ± 0.2} colony-forming units mL⁻¹) adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 10^8.2. The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 10^6.8 TBT molecules is adsorbed by a single cell.     

吸水膨胀型膨润土/交联聚丙烯酰胺颗粒堵剂

使丙烯酰胺、少量N，N-亚甲基双丙烯酰胺在钙膨润土存在下进行水溶液引发接枝共聚合，聚合产物经造粒、粉碎、筛分，得到粒径0．5～1．0mm的颗粒堵剂。根据颗粒堵剂吸水量大小确定丙烯酰胺与膨润土最佳质量比为7：1，引发剂最佳用量为500g／t，交联剂最佳用量为300g／t，吸水量与这3个参数之间的关系曲线都经过最大值，颗粒堵剂在去离子水中的吸水量为560～650mL/g。该堵剂已大规模生产，在胜利、中原油田许多采油厂已用于调剖、堵水和调驱施工，在青海、江苏、大港、冀东等油田也已开始使用。在胜利东辛采油厂的一个井组，连续3个月在3口井注入该堵剂共27t，使井口压力上升3MPa，产油量大幅度增加。表l参l。