润滑油分散剂分散性能的研究

区分不同结构分散剂的分散性能有益于分散剂的分子设计。通常实验方法费用高昂、效率低下，而计算机模拟方法则是一种非常有效的辅助研究方法。本文以润滑油分散剂的分散性能为研究目标，选择合适的模型化合物，定义了分散性能的计算指标，并用分子模拟方法估算了模拟需要的参数，运用介观模拟方法考察了分散剂结构、用量、与润滑油的相互作用等因素对分散性能的影响。得到了与实验研究一致的模拟结果。     

亚胺表面活性剂判别和活性预测

亚胺表面活性剂是1类新型的可逆表面活性剂,由于其可以通过调节pH和温度来控制其可逆过程,在药物缓释等领域中有潜在应用价值。用HyperChem计算了亚胺化合物的QSAR性质。通过聚类分析,可以判断某亚胺化合物是否是表面活性剂。利用逐步回归分析,得到了可以预测其表面性质的方程。醛基临界胶束浓度方程包含2个参数,Grid方法的范德华分子表面积,折射率,方程的相关系数为0.99992,标准差为0.14007。亚胺基临界胶束浓度方程包含2个参数,Grid方法的范德华分子表面积,极化率。方程的相关系数为0.99993,标准差为0.06169。水力直径方程包含2个参数,Approx方法的溶剂可接触部分分子表面积,Grid方法的溶剂可接触部分分子体积,方程的相关系数为1,标准差为0.00346。这些为进一步研究亚胺表面活性剂打下良好的基础。     

《计算机与应用化学》2005年22卷 第1—12期总索引

文章标题 作者 期页 一、分子模拟与分子设计 自乡t装二卜烷二拨基卜L一谷氮酸纳米管的分子模拟·······，·，··························，·····························，…程杰，刘波，杨震 丁二酞亚胺类分散剂在伪烟良表面吸附行为的分子动力学模拟············，·················……魏克成，温浩，周涵，徐未，许志宏 白喉毒素活性片段的电子结构研究·······，······························…     

一种水溶性苝系衍生物pH荧光探针的合成及表征

该文主要以苝四酸酐为起始物,通过在酸酐位置引入天冬氨酸,设计合成了一种水溶性的含有四个羧基的荧光苝二酰亚胺衍生物,研究了其在不同pH条件下的荧光光谱,发现所研究化合物的荧光强度与pH值间有着强烈的依赖关系,H+能有效地减弱此化合物的荧光,此化合物可用作测定溶液pH值的荧光探针.     

亚胺培南和左氧氟沙星治疗方案蒙特卡洛模拟的比较

依据抗菌药物的药动学/药效学原理,本文建立蒙特卡洛模拟模型,优化比较亚胺培南/西司他丁(剂量以亚胺培南计)和左氧氟沙星抗感染治疗的给药方案。模拟试验表明,亚胺培南0.5 g/8 h静脉滴注对鲍曼不动杆菌、肺炎克雷伯菌感染的疗效较好,累积反应分数(CFR)分别为97.28%和99.71%;对铜绿假单孢菌,低剂量的CFR不够理想,增大剂量可以提高CFR,但低于90%,提示经验治疗时须考虑联合用药。左氧氟沙星静脉滴注0.2g/d对卡他莫拉菌有效,CFR为100%;对肺炎克雷伯菌,0.2g/d、0.3 g/d、0.5g/d和0.75 g/d各治疗方案的CFRs相近,约为55%,增加剂量未能增强效果;对肺炎链球菌,0.5g/d的日剂量CFR达100%,可具有治疗效果。蒙特卡洛模拟可预测和优化抗菌药的用药设计,帮助临床选择合适的抗感染治疗方案。     

纳米孔单分子传感器电导特性有限元分析

主要从纳米孔结构角度,考虑生物分子在纳米孔内的位阻效应影响.运用有限元模拟方法分别模拟了3类常见纳米孔的电导,并比较了3种不同纳米孔在检测纳米杆通过纳米孔时的相对堵塞电流值大小.研究了纳米杆上带有亚结构时,在3种纳米孔内的电流堵塞效应的差异.研究方法有助于进一步理解纳米孔结构对检测生物分子的影响.     

自组装二十烷二羰基二-L-谷氨酸纳米管的分子模拟

为了洞察自组装二十烷二羰基二-L-谷氨酸(Eicosanedioyl—di—L—glutamic acid)EDGA球形螺旋纳米管微观结构，我们在大型计算机工作站SGI3800上，利用CERIUS2分子模拟软件，进行了计算机分子模拟。首先，根据EDGA分子在纳米管壁中的受力情况，确定了相当于二维周期边界条件的三维周期边界模型，由分子动力学构象搜索法寻找低能量的分子构象，进而运用分子力学、分子动力学交替进行的退火算法对EDGA单层膜聚集体进行模拟计算；结果得到分子两端基谷氨酸的构象不同的最低能量的分子构象，和螺旋与弯曲两种趋势同时存在的EDGA单层膜聚集体。模拟结果可以合理地描述自组装二十烷二羰基二-L-谷氨酸球形螺旋纳米管的一些结构特征。     

作物保护剂对磺酰脲类除草剂解毒效应述评

结合国内外学者以及作者自己对作物保护剂和磺酰脲类除草剂的研究,概述了保护剂对磺酰脲类除草剂的解毒作用。不同环境条件对保护剂的解毒作用有一定的影响,并从理论上证明保护剂通过抑制核苷二磷酸（RDP）,并间接抑制乙酰乳酸合成酶（ALS）的活性,从而对磺酰脲类除草剂进行解毒效应．     

合成N-杂环硅烯二氯前体{(C6H3-2,6-iPr2)NCH}2SiCl2(iPr=异丙基)的理论和实验研究

采用密度泛函B3LYP/6-31G*法,研究合成五元环二氯前体的起始物二亚胺(RNCH)2[1a R=C6H3-2,6-iPr2(iPr=isopropyl);1b R=tBu(tBu=tert-butyl)]及关键中间体二锂衍生物2的几何构型、能量和电荷分布.表明二亚胺中,N原子上取代基团的立体结构及N原子周围的电子环境,对二亚胺1的性质的影响很强,二亚胺1a比1b稳定,要求锂试剂应具有更好的反应活性才能反应生成二锂衍生物2;二亚胺1a的电荷分布表明,锂试剂应拥有比金属锂更强的亲电子能力,才有利于二亚胺形成二锂衍生物.基于理论上的预测,在温和的条件下合成了N-杂环硅烯所需的二氯前体(RNCH)2[1a R=C6H3-2,6-iPr2(iPr=isopropyl);1bR=tBu(tBu=tert-butyl)]并得到了很好的产率.     

酰基吡唑啉酮配体的设计

利用分子力学方法研究了1－苯基－3－甲基－4－（烟酰）－吡唑啉－5－酮（A）和1－苯基－3－甲基－4－（异烟酰）－吡唑啉－5－酮（B）及反应可能生成的烯醇式异构体（C）、（D）。系统搜索结果可以看出酮式能量最低，和实验结果相吻合，表明设计结果正确，为进一步设计开发新型配体提供了可靠的方法。     

Accelerating dissipative particle dynamics with multiple GPUs

Dissipative particle dynamics (DPD) simulation is implemented on multiple GPUs by using NVIDIA’s Compute Unified Device Architecture (CUDA) in this paper. Data communication between each GPU is executed based on the POSIX thread. Compared with the single-GPU implementation, this implementation can provide faster computation speed and more storage space to perform simulations on a significant larger system. In benchmark, the performance of GPUs is compared with that of Material Studio running on a single CPU core. We can achieve more than 90x speedup by using three C2050 GPUs to perform simulations on an 80∗80∗80 system. This implementation is applied to the study on the dispersancy of lubricant succinimide dispersants. A series of simulations are performed on lubricant–soot–dispersant systems to study the impact factors including concentration and interaction with lubricant on the dispersancy, and the simulation results are agreed with the study in our present work.     

The application of a.c. impedance technique for detecting glycol contamination in engine oil

A few hundred ppm of ethylene glycol (a major component in antifreeze) can cause detrimental changes m engine oil. In this work, the a.c. impedance technique has been employed to measure the bulk-layer resistance of engine oil containing glycol. It is found that the bulk-layer resistance declines abruptly as the glycol concentration increases from 50 to 150 ppm. In addition, the bulk-layer resistance for glycol-contaminated engine oil remains constant during a 10-day time span, indicating that the measured resistance is not affected by the formation of micelles between glycol and detergents/dispersants. However, commercial engine oils contain different amounts of detergents, and the bulk-layer resistance for fresh oils varies. Therefore, a software program is necessary to compare the bulk-layer resistance measured from fresh and glycol-contaminated engine oil in order to determine precisely the extent of glycol contamination.     

Revisions of the ADIOS oil spill model

For several years, the National Oceanic and Atmospheric Administration Hazardous Materials Response Division (NOAA/HAZMAT) has been using and distributing the computer software package called ADIOS™ (Automated Data Inquiry for Oil Spills) to aid responders in oil spill cleanup. ADIOS forecasts the weathering processes and characteristics of oil slicks. Based on new research results and analysis since the first version was released, a major update revises and improves previous algorithms, plus adds new modules for other weathering processes and for spill cleanup strategies. The weathering processes included in the new version, called ADIOS2, are spreading, evaporation, dispersion, sedimentation, and emulsification. The user cleanup options are dispersants, in-situ burning, and skimming. Different types of release scenarios can be simulated and the user is allowed to enter ranges for selected input variables with the resulting uncertainty displayed in the model output.     

Palm-print recognition by matrix discriminator

In this study, the characteristic matrix is employed to generate the various discriminators, by which to identify different palm-prints. The “ring rotation invariant transform” technique can deal with image rotation problem. In this study, the transformed signals will be fed to the characteristic matrix to generate various discriminators. For dealing with image-shifting problem, one pixel in sample image is compared with the surrounding pixels in unknown image to locate the closest matching. The comparison approaching in this study is by the basis of pixel-to-pixel-comparisons.     

Enterprise social media and cyber-slacking: A Kahn’s model perspective

This study investigates the associations between enterprise social media (ESM) use, psychological conditions, and cyber-slacking in the workplace and examines the mediating role of psychological conditions between ESM use and cyber-slacking. The study utilizes Kahn’s framework to develop a research model and investigate various associations, and it employs a cross-sectional design, testing the developed research model with 277 ESM users from Chinese enterprises. The study results suggest that ESM use stimulates various psychological conditions that discourage cyber-slacking behaviors and significantly mediate the associations between ESM use and cyber-slacking.     

Service process simulation for integrated service evaluation

The design of services has become an important issue discussed in various industries. For the design of attractive and sustainable services, it is important to satisfy the requirements of various stakeholders simultaneously. To evaluate the fulfillment of them in a quantitative manner, the process simulation of a service would be an effective approach. However, the method to develop a simulation model to evaluate a service with various evaluation criteria has not been proposed. In this study, the authors propose the evaluation framework and the service process model to describe the influence of a service to various stakeholders and suggest the simulation method based on it.     

Comparative analysis of Simulated Annealing,Simulated Quenching and Genetic Algorithms for optimal reservoir operation

The present study deals with the application of non-traditional optimization techniques, namely, Simulated Annealing (SA), Simulated Quenching (SQ) and Real-coded Genetic Algorithms (RGA) to a case study of Mahi Bajaj Sagar Project, India. The objective of the study is to maximize the annual net benefits subjected to various irrigation planning constraints for 75% dependable flow scenario. Extensive sensitivity analysis on various parameters used in above techniques indicated that they yielded same solution corresponding to a set of optimal combination of parameters. It is concluded that SA, SQ and RGA can be utilized for efficient planning of any irrigation system with suitable modifications.     

Type inference and type checking for queries over execution traces

We study here Type Inference and Type Checking for queries over the execution traces of Business Processes. We define formal models for such execution traces, allowing to capture various realistic scenarios of partial information about these traces. We then define corresponding notions of types, and the problems of type inference and type checking in this context. We further provide a comprehensive study of the decidability and complexity of these problems, in various cases, and suggest efficient algorithms where possible.     

循序渐进掌握CAD/CAE/CAM 技术

根据CAD/CAE/CAM 技术的特点和各教学课程的适应性,采用分课程侧 重学习该技术的某些内容、结合生产实际综合应用各知识点的教学方式,让学生在大学期间 熟练掌握CAD/CAE/CAM 技术,成为具有实际动手能力的工程技术人才。