HELIX-INDUCED ASYMMETRIC POLYMERIZATION

Asymmetric polymerization could be induced by an already formed optically active living prepolymer with one-handed screw sense helix conformation. The usually formed anionic active centre on the prepolymer could be changed to cationic, radical and even of Ziegler-Natta type. These living prepolymers with various kinds of active centre were all effective to induce a consequent asymmetric polymerization of a monomer which may be other than that in the prepolymer, to afford an optically active helical chain with the same screw sense as that of the prepolymer. Eight monomers have been used in the work. Optical rotation, circular dichroism and gelpermeation chromatography have been taken to prove the helix-induced asymmetric polymerization.

Metabolism of polychaete Neanthes japonica Izuka: relations to temperature, salinity and body weight

Polychaete Neanthes japonica is a species geographically specific in China and Japan with important scientific implication and commercial value. In this study, the relations of body weight, salinity and temperature to oxygen consumption and ammonia excretion of N. japonica were determined. Three different groups in body weight (large: 2.34 +/- 0.36 g, middle: 1.50 +/- 0.21 g and small: 0.62 +/- 0.12 g) were set for all experiments. Results show that the body weight is negatively related to the rates of oxygen consumption and ammonia excretion; and the relationship is significant. The oxygen consumption and ammonia excretion at 24A degrees C decreased at salinity from 5 to 30 and increased above 30, indicating that both lower and higher salinity are adverse and certain degree of salinity stress is necessary for enhancing the energy demand. At salinity 30, rising temperature from 18A degrees C to 30A degrees C, the oxygen consumption increased before 27A degrees C and then decreased. However, the relation of ammonia excretion and temperature seems more complex. Two-way ANOVA shows that salinity, temperature and body weight all have a significant effect on the oxygen consumption and ammonia excretion of the worm. Moreover, interaction between salinity/temperature and body weight is also significant. O:N (oxygen/nitrogen) ratio varies greatly in this case from 5.97 to 463.22, indicating that N. japonica can regulate the type of metabolic substrate against environment changes.

A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of Phascolosoma esculenta

Background: There are many advantages to the application of complete mitochondrial (mt) genomes in the accurate reconstruction of phylogenetic relationships in Metazoa. Although over one thousand metazoan genomes have been sequenced, the taxonomic sampling is highly biased, left with many phyla without a single representative of complete mitochondrial genome. Sipuncula (peanut worms or star worms) is a small taxon of worm-like marine organisms with an uncertain phylogenetic position. In this report, we present the mitochondrial genome sequence of Phascolosoma esculenta, the first complete mitochondrial genome of the phylum. Results: The mitochondrial genome of P. esculenta is 15,494 bp in length. The coding strand consists of 32.1% A, 21.5% C, 13.0% G, and 33.4% T bases (AT = 65.5%; AT skew = -0.019; GC skew = -0.248). It contains thirteen protein-coding genes (PCGs) with 3,709 codons in total, twenty-two transfer RNA genes, two ribosomal RNA genes and a non-coding AT-rich region (AT = 74.2%). All of the 37 identified genes are transcribed from the same DNA strand. Compared with the typical set of metazoan mt genomes, sipunculid lacks trnR but has an additional trnM. Maximum Likelihood and Bayesian analyses of the protein sequences show that Myzostomida, Sipuncula and Annelida (including echiurans and pogonophorans) form a monophyletic group, which supports a closer relationship between Sipuncula and Annelida than with Mollusca, Brachiopoda, and some other lophotrochozoan groups. Conclusion: This is the first report of a complete mitochondrial genome as a representative within the phylum Sipuncula. It shares many more similar features with the four known annelid and one echiuran mtDNAs. Firstly, sipunculans and annelids share quite similar gene order in the mitochondrial genome, with all 37 genes located on the same strand; secondly, phylogenetic analyses based on the concatenated protein sequences also strongly support the sipunculan + annelid clade (including echiurans and pogonophorans). Hence annelid "key-characters" including segmentation may be more labile than previously assumed.

对螺钉无轴向压力的高精度自动螺丝刀的设计

区别于现有的电动、气动螺丝刀工具,该螺丝刀系统在驱动螺丝时,能对螺钉头实现无轴向压力的调节。刀头在旋转的同时随螺钉轴向进给,转速与进给量匹配,保证刀头与螺钉不脱节。该系统调整精度高,刀头转动精度可达0.72°,其应用于断路器类低压电气产品的自动调试,对确保产品质量、提高生产效率具有积极意义。

具有自适应能力管道机器人的设计与运动分析

提出并研制一种基于自适应移动机构的管内探查机器人。通过对机器人传动机构的设计,实现了在不增加驱动电动机数量的前提下,机器人具有适应不同管道直径的能力。机器人的传动机构能够在管道直径改变时,自动地改变行走部件的输出形式以克服障碍,完成越障任务。在没有应用链式多节构型的情况下,机器人配备一个驱动电动机就能够完成越障任务,改善了传统螺旋驱动式机器人越障能力不高的问题,同时也提高了对驱动电动机的使用效率。为了分析试验中发现的机器人保持架自转现象,对机器人进行运动分析,并由分析结果对相关部分进行改进。试验结果表明,该机器人能够在内径为190 mm和180 mm的管道中行进,并能够顺利通过两节管道间形成的同心台阶障碍,验证了自适应移动机构的行走能力。

一种适用于多指灵巧手的机电一体化驱动器概念

本文提出了一种机电一体化驱动器的概念,这种驱动器能够将电机的旋转运动转换为直线运动,并在不外加力和力矩传感器的基础上利用运动转换副上产生的微应变来估算电机的输出力矩和驱动器末端的牵引力信息。利用高精度、高灵敏度并带有温度和噪声补偿电路的应变片来测量微应变,以取得稳定而可靠的测量结果。应变片直接贴在驱动器的主体结构表面可以最小化尺寸,而且可以实现机电一体化而不是机械-电子集成系统。仿真实验表明,这种方法和传统的电流估算法相比,可以减少由于噪音和波动带来的电流信号误差,得到更加精确的信息,并且(与加入力或者力矩传感器相比)能够有效缩小外型尺寸,同时去除不必要的机械与电子接口,因此增加了系统的鲁棒性。

大型铰接并联六维测力平台摩擦建模

在已有制造工艺及标定技术基础上,为进一步改善大型铰接并联六维测力平台的测量精度,本文基于螺旋理论和影响系数原理,引入符号函数建立了Stewart结构大型铰接六维测力平台的摩擦模型。文中提出了关节摩擦对铰接并联六维测力平台测量精度的影响矩阵及I、H类误差表达式,绘制了在不同外载和关节摩擦系数条件下,六维测力平台的I、II类误差曲线,并总结丁关节摩擦和平台自重对测力平台测量精度的影响规律。为具有普通球形铰链人型Stewart平台六维测力下台精度的提高和改善提供了理论基础。

并联结构六维力传感器性能分析与优化设计

基于螺旋理论和空间模型理论绘制了Stewart平台型六维力传感器的性能图谱,总结了结构参数对传感器各性能指标的影响规律;在此基础上对大型Stewart平台六维力传感器的结构进行了非线性单目标、多目标优化设计,为具有普通球形铰链大型Stewart平台六维力传感器的设计和优化提供了依据。

基于立体视觉的移动机器人自主导航定位系统

描述了一种基于立体视觉的移动机器人自主导航定位系统。该系统采用双目立体视觉完成环境特征的 3D信息提取 ,实时计算出机器人相对作业目标的位姿 (6D)关系 ,导引移动机器人控制系统按目标导向进行运动。系统在相对位姿计算中采用旋动(Screw)理论 ,将带约束的多变量函数的非线性优化问题转化为线性方程组的最小二乘问题 ,简化了计算复杂性。实验表明 ,这个导航定位系统在定位精度和数据处理速度上均可满足机器人导航的要求。

LW-1型机器人重复位姿精度检测系统

本文介绍了一种非接触式（ＬＷ－１型）机器人重复位姿精度检测系统．该系统采用电涡流传感器作为位置信息传感器．以这种传感器的检测性能为基础，研究设计了相应的传感器测量结构、数学模型和坐标变换求解方法，使系统技术指标及使用性能达到了检测机器人重复位姿精度的实用要求．该系统具有鲁棒性强、设计合理、结构简单、造价低廉等特点，可以满足我国现阶段在机器人学研究和机器人开发应用方面的需求

遥控作业移动机器人环境建模方法研究

本文介绍了用于遥控机器人作业虚拟环境生成的建模方法．重点研究了基于人机交互的双目立体视觉和多视点建模方法，以克服视觉自动建模方法计算复杂、鲁棒性差的缺点．给出了环境建模的实验系统和实验结果。

济阳坳陷及其南缘奥陶系碳酸盐岩潜山储集性及控制因素

The main research area of this thesis is Jiyang Depression in the Bohaiwan Basin and its southern margin. The object formation is Ordovician carbonate. The research is based on the outcrop observation and measurement of Ordovician carbonate and the drilling data of the oilfield. The internal reservoir characteristics of carbonate buried hill and its distribution were studied by comprehensive methods of sedimentology, reservoir geology and structural geology and technics of cathodoluminescence(CL)3electron microprobe,casting and C O isotope analysis etc. The influence depth of paleokarst facies formed during the Paleozoic is discriminated as 36-84m. The sollution porosity is well developed in paleokarst facies of Ordovician carbonate and is an important type of internal reservoir of buried hill. It may be infered that the fractures may be formed mainly during the Mesozoic and Cenozoic, they were not developed during the early Paleozoic when only micro-fractures might be created. The carbon and oxigen isotope analysis shows that the calcite cements in the fractures of Ordovician carbonate and secondary solution pores were related with meteoric water and three stages of fractures were divided. The reservoir space of Ordovician carbonate are mainly secondary porosity, cavern and fracture. The development of structural fracture was controlled by the lithology and tectonic background. More fractures exist in dolomite than that in limestone. There are also more fractures near the fault and the axis of fold. The development of porous reservoir is mainly controlled by the lithology and diagenesis, especially dolomitization and dissolution. It also results in the heterogeneity vertically. So the lithology is the basic factor for the forming of internal reservoir of buried hill and the tectogenesis and diagenesis are key factors to improve it. The porosity in carbonate might experienced solution-cementation-resolution or recementation. The porosity evolution history was a kind of historical dynamic equilibrium. The internal reservoir of Ordovician carbonate is the comprehensive result of constructive and/or destructive diagenesis. The worm's eye maps of the early Paleozoic and middle-upper Proterozoic were plotted. It was inferred that the paleostress field evoluted from NNW to NW during the Mesozoic and Cenozoic. Three types of buried hills can be divided: C-P/Pzi, Mz/ Pzi and E/ Pzi. The unconformity of the buried hill of E/ Pzi type, comparatively, was formed and reconstructed latestly, t he p orous r eservoir c ould b e w ell p reseved. T his c ondition w as v ery favorable t o t he migration and accumulation of oil and gas and could form upstanding association of source-reservoir-cap rocks. The buried hills of Mz/ Pzi and C-P/Pz] type were took second place.