The study on automorphism group of ESESOC

It is necessary to generate the automorphism group of a chemical graph in computer-aided structure elucidation. In this paper, an algorithm was developed by the all-paths topological symmetry algorithm to build the automorphism group of a chemical graph. A comparison of several topological symmetry algorithms reveals that the all-paths algorithm (APA) could yield the correct class of a chemical graph. It lays a foundation for the ESESOC system in computer-aided structure elucidation.

Phase transition temperature of HPT(2,3,6,7,10,11-hexa-n-pentyloxytriphenylene) from molecule dynamic simulation

Molecule dynamics simulation was used on HPT(2,3,6,7,10,11-hexa-n-pentyloxytriphenylene), which is a discotic Liquid crystal. From analyzing the energy and displacement varying with the temperature, the phase transition temperature of PM6MPP can be predicted. The deviations of T-g, T-m and T-i due to the MD time scale are small enough that it should be possibly used to predict the material properties especially when more powerful computers are available.

Chemical environment code and measure of molecular similarity

A new scheme for the code of chemical environments of compounds is described in this paper, and three molecular similarity methods have been used to select nearest neighbors from four different types of probe compounds. One of the methods is based on the C-13 NMR spectra. The second method is based on the code of chemical environments and molecular topological index A(x). The third approach, i.e. the Tanimoto coefficient, is also based on the code of chemical environments, but not to use the topological index. Five nearest neighbors for each probe compound using these three molecular similarity methods were determined and taken from the database of 7309 structures. The results indicate that the scheme of the chemical environment code and the method for similarity measure of intermolecules suggested in this study are reasonable. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

A NEWLY PROPOSED MOLECULAR TOPOLOGICAL INDEX FOR THE DISCRIMINATION OF CIS/TRANS ISOMERS AND FOR THE STUDIES OF QSAR/QSPR

A new topological index, the general a(N)-index (GAI), on quantum chemistry, is described in this paper. The GAI can be applied to molecules that contain heteroatoms and multiple bonds, and performs well in distinguishing cis/trans isomers. The relationships between the GAIs and physicochemical properties of olefins and neutral phosphorus compounds were observed with satisfactory results.

CORRELATION-ANALYSIS IN STRUCTURE AND CHROMATOGRAPHIC DATA OF ORGANOPHOSPHORUS COMPOUNDS BY GAI

This approach is undertaken to examine the correlation ability of the general a(N)-index (GAI) to predict chromatographic behavior. The test is performed on various types of organophosphorus compounds. The results demonstrate that the GAI possesses a good correlation with chromatographic properties.

Discovery of immune related factors in Fenneropenaeus chinensis by annotation of ESTs

A total of 10446 expressed sequence tags (ESTs) are obtained by a large-scale sequencing of a cDNA library from cephalothorax of adult Fenneropenaeus chinensis. An EST analysis platform was built up based on local computers and bioinformatic techniques were used to annotate these ESTs in order to promptly find possible functional genes, especially for immune related factors. About 4% of the ESTs show similarity to the coding sequences of such factors, including lectin, serine protease, serpin, lysozyme, etc. These ESTs provide a partial profile of the immune system in F. chinensis and useful information for further study on these genes.

基于web的远程控制机器人研究

Internet连接了全球的计算机 ,它为人们提供了分享数据、图片、影像甚至实时影像的机会 ,但与远程地点的真实交互还是离不开象机器人这样的智能设备 .Web技术与机器人控制技术的结合 ,促成了基于 web的远程控制机器人概念的诞生 .本文将就基于 web的远程控制机器人的发展历程、研究现状、主要技术与实现、发展趋势及应用前景等做综合的介绍 .

一个CIMS环境下的基于范例的船体装配CAPP系统

本文介绍了一个 CIMS环境下的基于范例的船体装配 CAPP系统 .包括 :CAPP系统在渤海造船厂 CIMS工程中的地位 ,基于范例的工艺规划 (范例的表达 ,范例的索引、存储、检索和适应 ) ,工艺定额和材料定额制定 ,分系统之间的信息集成 .系统采用 Power Builder和 SQL Server数据库中的 SQL语言编写 .目前 ,船体装配 CAPP系统已经在渤海造船厂的微机上连网运行

越野移动机器人自动驾驶专家系统的研究

本文研究越野移动机器人驾驶专家系统等有关问题．首先介绍了系统的硬件支持环境，然后阐述了自动驾驶专家系统的总体结构，有关知识库的内容以及使用知识的各功能模块的作用与运行机理．该系统已部分得以应用，能够完全代替驾驶员完成各种驾驶操作，并能进行自主导航、运动规划、自动绕障、动态跟踪目标、原路返回以及示教再现等复杂任务。

总线桥:概念、方法和实现

在基于不同总线标准的个人计算机、工程工作站以及一些工业控制机间建立高速的并行通信通道,将它们构成多机系统,能够以较小的代价获得增强的系统特性.本文引入了一种在系统总线间提供并行数据通道的异种总线互连底板——总线桥的概念,讨论了它的结构和工作原理,提出了其实现方案,并着重描述了为总线桥定义的双向并行通讯协议 BBP(Bus Bridge Prtocol)

计算机辅助机械绘图语言与系统设计

本文针对我国计算机绘制机械图领域内的现状,提出了一种易于掌握的机械图描述语言,以及一个相应的功能较强的绘图系统。该系统便于图形输入,并具有图形的平移、旋转、映射等功能,和较强的剖面域的处理能力。系统带有一个标注专用的笔写式字符库(包括汉字和专用符号)。该系统用 FORTRAN 语言写成,便于向大、中型计算机和存储容量较大的微型机移植。

地下水流动数值模拟的并行计算方法研究

Numerical modeling of groundwater is very important for understanding groundwater flow and solving hydrogeological problem. Today, groundwater studies require massive model cells and high calculation accuracy, which are beyond single-CPU computer’s capabilities. With the development of high performance parallel computing technologies, application of parallel computing method on numerical modeling of groundwater flow becomes necessary and important. Using parallel computing can improve the ability to resolve various hydro-geological and environmental problems. In this study, parallel computing method on two main types of modern parallel computer architecture, shared memory parallel systems and distributed shared memory parallel systems, are discussed. OpenMP and MPI (PETSc) are both used to parallelize the most widely used groundwater simulator, MODFLOW. Two parallel solvers, P-PCG and P-MODFLOW, were developed for MODFLOW. The parallelized MODFLOW was used to simulate regional groundwater flow in Beishan, Gansu Province, which is a potential high-level radioactive waste geological disposal area in China. 1. The OpenMP programming paradigm was used to parallelize the PCG (preconditioned conjugate-gradient method) solver, which is one of the main solver for MODFLOW. The parallel PCG solver, P-PCG, is verified using an 8-processor computer. Both the impact of compilers and different model domain sizes were considered in the numerical experiments. The largest test model has 1000 columns, 1000 rows and 1000 layers. Based on the timing results, execution times using the P-PCG solver are typically about 1.40 to 5.31 times faster than those using the serial one. In addition, the simulation results are the exact same as the original PCG solver, because the majority of serial codes were not changed. It is worth noting that this parallelizing approach reduces cost in terms of software maintenance because only a single source PCG solver code needs to be maintained in the MODFLOW source tree. 2. P-MODFLOW, a domain decomposition–based model implemented in a parallel computing environment is developed, which allows efficient simulation of a regional-scale groundwater flow. The basic approach partitions a large model domain into any number of sub-domains. Parallel processors are used to solve the model equations within each sub-domain. The use of domain decomposition method to achieve the MODFLOW program distributed shared memory parallel computing system will process the application of MODFLOW be extended to the fleet of the most popular systems, so that a large-scale simulation could take full advantage of hundreds or even thousands parallel processors. P-MODFLOW has a good parallel performance, with the maximum speedup of 18.32 (14 processors). Super linear speedups have been achieved in the parallel tests, indicating the efficiency and scalability of the code. Parallel program design, load balancing and full use of the PETSc were considered to achieve a highly efficient parallel program. 3. The characterization of regional ground water flow system is very important for high-level radioactive waste geological disposal. The Beishan area, located in northwestern Gansu Province, China, is selected as a potential site for disposal repository. The area includes about 80000 km2 and has complicated hydrogeological conditions, which greatly increase the computational effort of regional ground water flow models. In order to reduce computing time, parallel computing scheme was applied to regional ground water flow modeling. Models with over 10 million cells were used to simulate how the faults and different recharge conditions impact regional ground water flow pattern. The results of this study provide regional ground water flow information for the site characterization of the potential high-level radioactive waste disposal.

三维非均匀各向异性介质中的纵波走时反演研究

Many observations show that seismic anisotropy is very common in the crust and upper mantle of the Earth. Seismic anisotropy can provide some clue about the changing and transporting process inside the earth. in recent years, abundant earthquake travel time data are accumulated, computers become more powerful, and these make the inversion of earthquake travel time data practical. In this thesis we studied the theory of elastic wave in anisotropic media, some formule for travel time inversion were derived. We present an iterative procedure to determine 21 elastic parameters from qP wave travel times. No a priori assumptions about heterogeneity and anisotropy of the model are made. The procedure is suitable for the case when we know nothing about the symmetry of anisotropy of the media, as well as for the case of earthquake travel time inversion which may contain various symmetry of anisotropy. The procedure is tested with a synthetic multiple-source offset VSP experiment. The results proved that the formulae are correct, and the procedure is practical. The results and the related theory indicate that the anisotropic inversion needs more rays than isotropic case. For a 2-D weak anisotropic (WA) medium, we need at least 5 rays in different directions to retrieve the elastic parameters on one grid point, and for a 3-D WA medium we need at least 15 rays in different directions to retrieve the elastic parameters on one grid point. The results also indicate that the starting background velocity has no influence on the final results, at least for the model we specified. Our results also show that insufficient illumination coverage will slow down the convergence rate, and make the results more sensitive to noise. We apply the procedure to a set of field travel time data. The data is from an artificial seismic observation. This observation is for locating micro-seismic events around a tunnel, its purpose is to find out if the digging process and the stress condition around the tunnel can generate micro-cracks. The size of this area is around 100m. The anisotropy derived from qP travel times is the same as the anisotropy showed by apparent velocities, and is also consistent with the anisotropy derived from S-wave splitting phenomena.

DAS24-3B数据采集系统控制系统软件的研制与开发

Under the auspices of the 'knowledge-Innovation Program' of CAS, Institute of Geology and Geophysics has established the Broadband Seismic Laboratory. A new kind of 24-bit high-resolution seismograph DAS24-3B has been designed and manufactured in an effort of developing China's own technology of seismic array. Since these instruments will primarily be used in field operation, there is a need to optimize the system software of data acquisition system (DAS) to enhance its stability, compatibility and maintenance. The design ideas of the system software of DAS24-3B are partly learned from the advanced DAS 72A-08. In this system there are two exclusive communication programs DNAPI-COM1 and DNAPI-LPT1, which are suitable for all standard industrial computers with ECP parallel port and serial port. By these exclusive parallel and serial communication interface the system software is split into three parts, acquisition program, user's control program and graphical display program, which can function well in separate units and can run correctly in whole. The three parts of DAS24-3B's system software possess different functions and advantages. The function of acquisition program is to control the process of seismic data acquisition. DAS24-3B system reduced its power and harddisk read-write disturbance by using the extended memory attached to its CPU, which functions as enlarging the data buffer of system and lessening the times of harddisk read-write operations. Since GPS receiver of DAS is strongly sensitive to the around environment and has the possibility of signal loss the acquisition program has been designed with the ability to automatically trail the GPS locked time. The function of user's controlling program is to configure the system's work environment, to inform the user's commands to DAS, to trail the status of DAS in real-time. The function of graphical display program is to illustrate data in figures, to convert data file into some common formatted file, to split data file in parts and combine data files into one. Both user's control program and graphical display program are API (Application Programming Interface) in window 95/98 system. Both possess the features of clearness and friendship by use of all kind of window controls, which are composed by menu, toolbar, statusbar, dialogue box, message box, edit box, scrollbar, time control, button and so on. Two programs of systemic exception handles are provided to treat the trouble in field. The DAS24-3B DAS has been designed to be easier to use-better ability, more stable and simpler. It has been tested in field and base station and has been proved more suitable for field operation of seismic array than other native instruments.