Kinematics Analysis Based on Screw Theory of a Humanoid Robot

A humanoid robot is a complex dynamic system for its idiosyncrasy. This paper aims to provide a mathematical and theoretical foundation for the design of the configuration, kinematics analysis of a novel humanoid robot. It has a simplified configuration and design for entertainment purpose. The design methods, principle and mechanism are discussed. According to the design goals of this research, there are ten degrees of freedom in the two bionic arms. Modularization, concurrent design and extension theory methods were adopted in the configuration study and screw theory was introduced into the analysis of humanoid robot kinematics. Comparisons with other methods show that： 1） only two coordinates need to be established in the kinematics analysis of humanoid robot based on screw theory; 2） the spatial manipulator Jacobian obtained by using twist and exponential product formula is succinct and legible; 3） adopting screw theory to resolve the humanoid robot arms kinematics question can avoid singularities; 4） using screw theory can solve the question of specification insufficiency.     

渐开线螺旋面展开图的探讨

通过对渐开线螺旋面的讨论,从中推出较简捷的展开方法,为工程中渐开线螺旋面的展开下料提供了一种较好的方法。     

汽车转向梯形机构最佳参数确定

对不同转向梯形机构给出了内外轮转角的关系，用加权量小二乘法和复合形法、约束随机射线法进行机构最佳参数确定；文中给出了算例，说明迭代过程收敛计算结果可信。     

水溶液中苯酚在阳光下催化氧化降解的初步研究

介绍了一种以加碳焙烧法改性的膨润土作载体，用溶胶－凝胶法制备的新型TiO2-Ag复合催化剂，研究了该催化剂在阳光下对水样中苯酚的催化氧化降解条件，影响因素和降解率，结果表明，该催化剂有较高的催化氧化活性，在通入空气的条件下，对PH＝4．0，浓度为5mg/L的苯酚水样处理3h，其苯酚去除率可达98％左右，该催化剂性能稳定，易于沉降分离，回收后经高温活化，可反复多次使用，为高效，经济地利用日光催化氧化含酚废水的进一步研究提供了实验依据。     

Monitoring grinding wheel redress-life using support vector machines

Condition monitoring is a very important aspect in automated manufacturing processes. Any malfunction of a machining process will deteriorate production quality and efficiency. This paper presents an application of support vector machines in grinding process monitoring. The paper starts with an overview of grinding behaviour. Grinding force is analysed through a Short Time Fourier Transform (STFT) to identify features for condition monitoring. The Support Vector Machine (SVM) methodology is introduced as a powerful tool for the classification of different wheel wear situations. After training with available signal data, the SVM is able to identify the state of a grinding process. The requirement and strategy for using SVM for grinding process monitoring is discussed, while the result of the example illustrates how effective SVMs can be in determining wheel redress-life.     

Embedding ultrasmall Ag nanoclusters in Luria-Bertani extract via light irradiation for enhanced antibacterial activity

Ultrasmall silver nanoclusters(Ag NCs)with rich surface chemistry and good biocompatibility are promising in antibacterial application,however,further development of Ag NCs for practical settings has been constrained by their relatively weak antibacterial activity.Using the nutritionally-rich medium for bacteria(e.g.,Luria-Bertani(LB)medium)to coat active Ag NCs could further improve their antibacterial activity.Here,we provide a delicate design of a highly efficient Ag NCs@ELB antibacterial agent(ELB denotes the extract of LB medium)by anchoring Ag NCs inside the ELB species via light irradiation.The as-designed Ag NCs with bacterium-favored nutrients on the surface can be easily swallowed by the bacteria,boosting the production of the intracellular reactive oxygen species(ROS,about 2-fold of that in the pristine Ag NCs).Subsequently,a higher concentration of ROS generated in Ag NCs@ELB leads to enhanced antibacterial activity,and enables to reduce the colony forming units(CFU)of both gram-positive and gram-negative bacteria with 3–4 orders of magnitude less than that treated with the pristine Ag NCs.In addition,the Ag NCs@ELB also shows good biocompatibility.This study suggests that surface engineering of active species(e.g.,Ag NCs)with nutritionally-rich medium of the bacteria is an efficient way to improve their antibacterial activity.     

高层建筑结构构思与建筑创作

本文通过实例探讨了高层建筑创作合理进行结构构思，处理建筑功能，技术与艺术矛盾的方法和规律。     

问题解答

致读者:本刊1980年第11期刊载了“爆炸成型大型封头”后,收到不少读者来信,现请作者就大家提出的问题综合答复如下。〔答〕:爆炸成型的原理是利用雷管引爆,炸药在爆炸的一瞬间释放出的能量使坯料成型。爆炸瞬时产生的冲击波到达坯料表面时,峰值压力可达数千大气压,故坯料成型也是在一瞬间,因此,爆炸成型与机械模压不一,它属于高能高速成型技术。无模爆炸成型不需要压机和金属模具,但也有用胎模圈和压边圈限制     

TS分子筛的催化氧化性能研究

用自掣是四丙基溴化铵（ＴＰＡＢｒ）部分取代四丙基氢氧化铵（ＴＰＡＯＨ）为模板剂,在Ｎａ＾＋离子存在下,合成出结构优良的ＴＳ－１分子筛。在丙烯Ｈ２Ｏ２氧化制环氧丙烷反应中,考察了合成的ＴＳ－１分子筛的催化活性,催化剂的预处理。用量、利用次数、再生和反应温度与时间对反应的影响。研究表明,不同的模板和合成条件明显影响分子筛的晶粒大小。晶粒度为０．４￣０．７μｍ的ＴＳ－１分子筛经１０％ＮＨ４Ａｃ预处理后,     

新建长途电信枢纽楼的选址问题

新建长途电信枢纽楼(以下筒称新建枢纽楼)是集长途(含有线、无线、卫星通信)、数据及各种非话增值业务等通信的综合电信楼,其局址选择是否恰当将直接影响到通信安全和经济效益。本文主要说明选择局址时应注意的问题。