基于Pro/E二次开发的注射机双曲肘合模机构的参数化设计

利用机构学的方法对双曲肘合模机构进行了运动分析,并确立了合模行程、各肘杆尺寸及最大启模角等参数间的关联关系。通过使用Pro/E二次开发技术,讨论了应用Pro/toolkit进行菜单开发及零件参数化实现的方法;以MFC对话框设计技术和VC++建立了双曲肘合模机构参数驱动自动生成技术,开发出了与Pro/E 4.0系统集成的合模机构零件参数化设计系统。     

LAMMPS framework for dynamic bonding and an application modeling DNA

We have extended the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) to support directional bonds and dynamic bonding. The framework supports stochastic formation of new bonds, breakage of existing bonds, and conversion between bond types. Bond formation can be controlled to limit the maximal functionality of a bead with respect to various bond types. Concomitant with the bond dynamics, angular and dihedral interactions are dynamically introduced between newly connected triplets and quartets of beads, where the interaction type is determined from the local pattern of bead and bond types. When breaking bonds, all angular and dihedral interactions involving broken bonds are removed. The framework allows chemical reactions to be modeled, and use it to simulate a simplistic, coarse-grained DNA model. The resulting DNA dynamics illustrates the power of the present framework.Program summaryProgram title: LAMMPS Framework for Directional Dynamic BondingCatalogue identifier: AEME_v1_0Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEME_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: GNU General Public LicenceNo. of lines in distributed program, including test data, etc.: 2 243 491No. of bytes in distributed program, including test data, etc.: 771Distribution format: tar.gzProgramming language: C++Computer: Single and multiple core serversOperating system: Linux/Unix/WindowsHas the code been vectorized or parallelized?: Yes. The code has been parallelized by the use of MPI directives.RAM: 1 GbClassification: 16.11, 16.12Nature of problem: Simulating coarse-grain models capable of chemistry e.g. DNA hybridization dynamics.Solution method: Extending LAMMPS to handle dynamic bonding and directional bonds.Unusual features: Allows bonds to be created and broken while angular and dihedral interactions are kept consistent.Additional comments: The distribution file for this program is approximately 36 Mbytes and therefore is not delivered directly when download or E-mail is requested. Instead an html file giving details of how the program can be obtained is sent.Running time: Hours to days. The examples provided in the distribution take just seconds to run.     

Preventing progressive collapse through strengthening beam-to-column connection, Part 2: Finite element analysis

This two-part paper presents part of the results of a study devoted to the investigation of retrofitting effect of simple steel construction. Through strengthening simple beam-to-column connection, progressive collapse can be prevented by catenary action. The evaluation of catenary action represents a complex analytical problem with a large tension affecting its structural behavior. With the advent of high speed computers and powerful calculation software package, the finite element method offers an ideal tool for tackling such a complex problem. This paper develops sophisticated one-, two- and three-dimensional models of catenary action, and simulates the post-attack behavior of the original and the strengthened structures by means of the ABAQUS finite element package. The global behavior of the one-dimensional beam element model is close to that corresponding to the two-dimensional solid or the three-dimensional shell models, particularly for the structures with strengthened joints. Comparison of results between this study and literature has been carried out for the purpose of validating the present finite element prediction model. Through the comparing computational results before and after strengthening, the advantages of proposed retrofitting scheme are demonstrated.     

Total carotenoid differences in scallop tissues of Chlamys nobilis (Bivalve: Pectinidae) with regard to gender and shell colour

The aim of this study was to investigate whether total carotenoid content (TCC) in noble scallop Chlamys nobilis is related to body tissue, shell colour, and gender. TCC was determined by a UV–vis recording spectrophotometer in tissue of gonad, adductor, mantle, and gill separately sampled from male and female individuals with orange and brown shell colours from the same cultured population. TCC was significantly different among body tissues, depending on shell colour and gender, ranging from 0.73 to 59.85 μg g⁻¹. In general, TCC was greater in the order of gonad > mantle > adductor > gill. In the same gender, orange shell colour individuals contained significantly higher TCC than brown ones in all four tissues (P < 0.05). In the same shell colour, female contained significantly higher TCC than male in gonad and adductor tissues (P < 0.05).     

New unstructured mesh water quality model for coastal discharges

A new unstructured mesh coastal water and air quality model has been developed that includes species transport, nonlinear decay, byproduct formation and mass-exchange between sea and atmosphere. The model has been programmed with a graphical interface and is applicable to coastal seawater, lakes and rivers. Focused on species conversion and interaction with the atmosphere, the water and air quality model follows a modular approach. It is a compatible module which simulates distributions based on fluid dynamic field data of underlying existing hydrodynamic and atmospheric simulations. Nonlinear and spline approximations of decay and growth kinetics, byproduct formation and joint sea–atmosphere simulation have been embedded. The Windows application software includes functions allowing error analysis concerning mesh and finite volume approximation. In this work, an anoxic submerged process-water discharge has been simulated. An error analysis has been carried out by varying vertical meshing, time-steps and comparing results based on explicit and implicit finite volume approximation.     

Reliability and component importance analysis of substation automation systems

This paper aims to present a comprehensive technique to quantitatively assess the reliability of substation automation systems. The technique is based on the tie-sets methodology. In order to demonstrate the application of the proposed technique, a variety of substation automation architectures is first introduced. The associated reliability block diagrams as well as the exact system reliability are then given. The impacts and the degree of importance of various components on the reliability of substation automation systems are presented. Two suitable measures of importance are selected. The first is the Birnbaum’s measure used to determine the bottleneck of the system reliability. The second measure uses criticality importance to diagnose failures and generating repair or inspection checklists.     

不同香型凤凰单丛加工过程香气特征变化规律研究

采用同时蒸馏萃取(SDE)法提取鸭屎香单丛、乌叶单丛、八仙单丛三个香型茶香气成分,并用gas chromatography and mass spectrometry(GC-MS)进行检测分析,追踪比较其在加工过程的变化。实验表明鲜叶的青叶醛、叶醇等青草木香成分在"三青"环节消减,罗勒烯、茉莉酮、橙花叔醇等花果香成分在"三青"环节增多,吡咯等烘烤熟香成分在烘焙环节出现。鸭屎香单丛的杏仁香特征成分在晒青到杀青环节产生,如摇青产生的苯甲醇等;八仙单丛的芝兰香特征与鲜叶的花香成分有关系,晒青、摇青、烘焙加工进一步补充加强;乌叶单丛加工产生正辛醇、香茅醛等24种新成分,极多而复杂,稍有异于以往研究,但主旋律不变。各香型主导成分橙花叔醇与芳樟醇的含量比例特征规律在加工中不断形成。各香型茶鲜叶以醇类为主,加工产生萜烯类、酮类、酯类等,香型不同变化趋势不同。实验为研究凤凰单丛香型的产生机理打下基础。     

软土动剪切模量与微观孔隙结构试验研究

 为了从土体微观结构的角度定量地研究动剪切模量的性质和变化,利用共振柱试验,并借助电子显微镜及微观孔隙结构分析手段,对粤东重塑软黏土动剪切模量随动剪应变衰减规律与宏微观条件下土颗粒孔隙特性的关系进行分析。根据基于Davidenkov三参数模型的非线性回归分析和微观孔隙结构的参数计算分析,得到随固结应力增加,最大动剪切模量增大,连续介质中机械波波速增强;土体的宏观孔隙比降低;孔隙的层次增加,孔隙周长–面积分形维度值增加;孔隙的均一化程度增加,孔隙分形维度值减小。研究表明,Davidenkov模型中的初始参数、范围参数及速率参数与微观孔隙结构参数存在对应关系,为软黏土动力特性与微观结构关系的理论研究提供依据。     

响应面试验优化脆江蓠多糖提取工艺及其对肿瘤细胞的抑制作用

目的：研究脆江蓠多糖（Gracilaria chouae polysaccharides,GLP）的提取方法及其对肿瘤细胞生长的影响。方法：响应面法优化GLP提取工艺条件;四甲基偶氮唑蓝（methyl thiazolyl tetrazolium,MTT）法检测GLP对体外培养的人宫颈癌（HeLa）、食道癌（EC-109）、肝癌（HepG-2）以及乳腺癌（MCF-7）细胞生长的影响。结果：GLP最佳提取条件为预热温度93.1 ℃、料液比1∶61.5（g/mL）、超声时间35 min,在此条件下GLP提取率为16.75%。GLP在质量浓度200～1 000 μg/mL范围内对实验细胞均有抑制作用,且呈剂量依赖关系。当GLP质量浓度为1 000 μg/mL时,其对HeLa、HepG-2、MCF-7和EC-109细胞的抑制率分别为49.11%、41.18%、34.98%和31.33%。对HeLa细胞形态学观察以及Annexin V-FITC/PI荧光染色检测发现,随着GLP给药剂量的增加,凋亡和坏死细胞不断增多。结论：GLP对体外培养的人HeLa、EC-109、HepG-2以及MCF-7等癌细胞增殖有抑制作用,并能诱导肿瘤细胞凋亡。     

无线局域网的速率自适应算法设计与仿真分析

目前的IEEE802.11在物理层提供了不同的传输速率,因此根据不同的信道条件可以选择一个合适的传输速率,以使系统吞吐量达到最大。在WLANs中,当有多个用户向同一个接入点传输数据时,碰撞就会产生。Collision-Aware Rate Adaptation（CARA）算法能够有选择地启用Request-To-Send/Clear-To-Send（RTS/CTS）识别出这种碰撞,很大程度上避免了由于碰撞引起的吞吐量下降。但随着碰撞的增加,CARA吞吐量还是有明显下降。为了提高吞吐量,提出了一种新的速率自适应算法Adaptive Avoid Collision Rate Adaptation（Adaptive-ACRA）,该算法根据信道条件不同改变门限值,有效地提高了大量碰撞存在情况下的吞吐量。最后,通过大量NS2仿真证明了新算法提高系统吞吐量的有效性。