3-RRRT并联机器人位置分析

本文旨在研究和分析3 RRRT并联机器人位置的正、反解问题.运用了齐次坐标系法和空间矢量法对3 RRRT并联机器人机构进行了分析,用解析的方法给出了该并联机器人的8组位置反解,采用数值方法给出了该并联机器人的位置正解.并基于I deas系统下的实体模型,应用MATLAB语言及其优化工具箱,实例验证了该数学模型的正确性.     

3-RRRT并联机器人位置分析

本文旨在研究和分析3-RRRT并联机器人位置的正、反解问题．运用了齐次坐标系法和空间矢量法对3-RRRT并联机器人机构进行了分析，用解析的方法给出了该并联机器人的8组位置反解，采用数值方法给出了该并联机器人的位置正解．并基于I-deas系统下的实体模型，应用MATLAB语言及其优化工具箱，实例验证了该数学模型的正确性．     

一种三转动并联机构的运动学及解耦性分析与仿真

对一种支链含等速万向节的RRR-PaRRS-RHJ型三转动并联机构的运动学及其解耦特性进行分析.首先,对机构进行运动特性分析和自由度计算.然后,通过构件间的几何关系对机构进行运动学分析,给出机构位置正、逆解析解,推导出机构在定坐标系和动坐标系下的速度雅克比矩阵,根据雅可比矩阵分析此机构在不同坐标系下表现的不同耦合性.最后,运用ADAMS软件进行运动学仿真,验证了理论分析的正确性.     

精密并联机器人系统误差的分析与补偿

为减小机构末端定位误差,提高精密并联机器人运动精度,以6-HTRT并联机构为结构模型,分析了机构的各种制造误差。首先在机构上开发了一种新型虎克铰链,同时采用了预紧装置;然后在控制系统中引入DSP高性能数据处理器;最后,用矢量构造的方法计算机构速度Jacobian矩阵,用数值法计算位置正解,用构造法计算误差Jacobian矩阵,对机构末端误差进行补偿。通过以上措施,可以使系统的精度提高到机构重复运动精度的3倍左右,满足精密并联机器人工作的精度要求。其中,软件误差补偿算法不受并联机构类型的限制,有较大的适用范围。     

利用位置正解分析并联机构奇异分布规律

利用位置正解分析了并联机构奇异的分布规律.首先采用数值法求出了并联机构所有位置正解构型；然后分析了并联机构奇异与构型空间的关系；接着给出奇异的判别标准Jacobi矩阵的求法；最后沿着构型空间的边界分析了并联机构奇异的分布规律.结论对并联机构的运动控制及规划具有重要意义.     

基于结式消去法的并联机构位置解析

目的并联机构位置解析的核心问题是求解一组非线性方程组,为此提出一种消去法使并联机构位置方程降维,以便采用同伦方法求得位置方程全部解。方法从并联机构位置约束方程出发,采取狄克逊结式对位置正解方程进行消元,从而得到机构位置正反解封闭方程;采用同伦方法和利用MATLAB数学软件进行求解。结果利用MATLAB数学软件编制的狄克逊结式消元和同伦算法的数学机械化程序,得到Delta型并联机构位置问题的全部数学解。结论结式消去法为并联机构位置解析提供了十分有效的通用方法,而且可用于解决其他更为复杂的体系。     

3-RRRT并联机器人的位置正解研究

本文介绍了一种新型3-RRRT并联机器人的特点,推导了该机器人的位置反解方程,获得了其位置反解,采用数值方法给出研究了该并联机构的运动学正解.运用Matlab软件计算进行了验证.     

丝传动3-S■R并联机构运动学分析与力反馈控制

并联机构刚性高且动态性能好,用于开发力反馈设备时,在力觉刚性以及位姿分辨率方面优势明显.学界与业界多基于Delta机构开发高性能并联力反馈设备,本文采用3-S■R并联机构设计和开发出一种新型力反馈设备.采用丝传动方式并基于差动原理,提出了一种新型直线动单元作为3-S■R并联力反馈机构驱动副,有效提升了力反馈设备的位姿分辨率与力觉刚性.并联机构的位置正解效率直接影响操控力反馈设备的实时性,本文以动平台中心和球铰链中心距为中间变量,构造出量纲统一的迭代矩阵,实现了该机构位置正解模型的高效求解.相较于传统位置正解的数值方法,求解效率提升近一个数量级,大幅提升了该力反馈机构的位姿反馈实时性.在运动学模型的基础上,基于虚功原理建立了力反馈机构的力映射模型,提出一种含机构重力补偿的反馈力计算方法.基于上述方法开发算法并设计出控制系统,实现了力反馈机构的位姿实时监控及反馈力控制.通过重力补偿实验,验证了上述方法及其控制系统的有效性.     

一种可实现两平动自由度并联机构运动学标定方法

针对一种两平动自由度并联机构，提出了一种识别几何参数误差的方法，能有效补偿机构的动平台位姿耦合误差．忽略两组平行杆的相对杆长误差，将机构简化成仅含转动副的5杆铰接机构，建立了含有8个几何参数误差模型，即4个杆长误差和4个主动关节铰点坐标误差．研究表明，并联拓扑结构使动平台沿两个正交轴的位置误差和姿态误差具有强耦合性．给出标定坐标系原点，通过仅检测动平台沿标定坐标系任一单轴的位置误差，识别出系统的几何误差全集．计算机仿真和实验结果表明，通过这种方法，可使机构的动平台定位精度达到0．05mm．     

桥上CRTSII板式无碴轨道施工技术

简述国内外高速铁路无碴轨道的发展概况,针对高速铁路施工精度要求高、工序控制严格的特点,结合京津城际轨道交通工程实例,研究了博格板式无碴轨道的施工技术,对德国博格公司的施工工艺做了改进。同时,在施工中采用了许多新材料和新工艺,主要有电气绝缘、轨道板的吊装与铺设、CA砂浆、轨道板的张拉等。应用了高度可调节的底座板模板,改进了轨道板粗铺定位方法,从而保证了施工精度要求;设置的临时端刺以及移动门式起重机配合吊车的轨道板吊装就位方法加快了施工进度。工程实践证明,该法精度高,施工工期短,经济效益明显。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to