压缩机通用型线结构建模与动力学特性分析

涡旋制冷压缩机的结构建模与动力学特性分析是提高压缩机整机性能的有效途径.取泛函通用涡旋型线的特殊涡旋型线对其研究,利用MATLAB软件编程,得到关于切向角参数φ的相应空间坐标,接着利用PRO/ENGINEER软件对部件进行三维建模,然后在PRO/ENGINEER的ASSEMBLY模块下进行装配,在设定的变频与定频两种驱动模式下对机构模块进行动力学特性分析,得出压缩机在两种驱动模式下的特点以及对两种模式工况差异的原因,此研究对其提高制冷压缩机的整机性能有其重大意义.     

Biosynthesis of Polyhydroxyalkanoates

IntroductionPolyhydroxyalkanoates ( PHA) is a family ofintracellular biopolymers synthesized by manybacteria as intracellular carbon and energy storagegranules ( Figs.1 and 2 ) .PHA is normallysynthesized under conditions of restrictedgrowth[16] .Industrial production has been used toproduce PHAs that are environmentally degradablethermoplastics[710 ] .Fig.1　 General m olecular structure ofpolyhydroxyalkanoatesm=1,2 ,3,yet m=1is the m ost common,n can range from10 0 to several thousand.R…     

Effect of Surface Modification on Microbiol Polyhydroxyalkanoate Films on Biocompatibility

IntroductionPolyhydroxyalkanoates,abbreviated as PHA,is afamily of biopolyesters synthesized by manyorganisms[1,2 ] ,with over1 0 0 different types basedon the length and composition of the carbon chain.PHA behavior is similar to that of conventionalplastics such as polyethylene and polypropyleneexcept that they are biodegradable;therefore,there have been many research projects to developPHA into a biodegradable plastic[3 ,4 ] .However,the high production costof PHA has prohibited itswide …     

基于测量机器人的工业机器人校准方法研究

在对高精度测量机器人、激光跟踪测量系统进行全面分析与系统研究的基础上,提出运用工业机器人与测量机器人对接,工业机器人带动测量机器人在整个工业机器人工作空间进行自动测量的方法.给出了工业机器人带动测量机器人联动测量的结构图和工业机器人空问误差的检测与补偿的流程图,为研究工业机器人末端误差测量提供新的理论与技术支持.     

Ⅰ-Ⅰ型易溶盐溶度积的探讨(Ⅰ)

定量地研究了Ⅰ -Ⅰ型易溶盐的溶度积。研究了“水合效应”和温度效应对该溶度积的影响     

高速公路沥青路面大中修质量控制重点

制定和采取科学的施工工艺和严格的质量控制手段,是提高沥青路面大中修质量的关键.本文从原材料、沥青混合料、施工过程等几个方面探讨沥青路面大中修施工质量控制问题.     

高压大流量水阀U形密封圈失效机理

以高压大流量水阀的U形橡胶密封圈为对象进行受力分析;选取Mooney-Rivlin模型表征橡胶材料,基于ANSYS/LS-DYNA软件实现阀杆往复密封结构的三维非线性接触动力学仿真,得到介质压力、阀杆运动速度和方向、表面摩擦因数以及阀杆径向受力等因素对密封圈应力状况的影响规律,确定U形橡胶密封圈失效的边界条件.实验结果表明:U形密封圈的沟槽、内唇口及底孔边缘是最大应力发生的主要部位,静态下密封圈最大应力比介质压力高8～10 MPa,阀杆正向运动时密封圈最大应力受摩擦因数的影响明显但处于安全范围,阀杆反向运动时密封圈最大应力主要受滑动速度影响,阀杆摆动时最大应力随径向力成近似正比增大.仿真结果与实际失效特征吻合.     

多目标优化量子免疫算法求解基站选址问题

为了解决带容量约束WCDMA网络的基站选址问题,提出了一个基于多目标优化量子免疫算法的基站选址优化方案.设计了基站选址问题的数学模型,给出了多目标优化量子免疫算法框架,并进行了实验验证.实验结果表明：算法方案能以较小的基站建设代价满足覆盖要求,具有较好应用价值.     

Sonochemical Decolorization of Methyl Orange in Aqueous Solution

The sonochemical decolorization of Methylene Orange was studied using a 24 kHz Ultrasound device with a 1.4 cm diameter horn. pH, power density, the effects of pH and power density on decolorization were discussed. The combined effect of radiate time, the initial concentration of dyes and the addition of Fe^2＋ on the decolorization was studied using response surface methodology. The results showed that the factorial central composite design was successfully employed for experimental design and predication of the results. AtpH = 2.8, T=30℃, power denstity= 300 W/L and Fe^2＋ of 2 mg/L, the decolorization percentage of 5 mg/L dye solution reached 96% after 60 mill ultreatment. The rate of decolorization of the dye was greatly improved in the presence of Fe^2＋. The sonolysis of the dye followed first-order kinetics.     

用教育测量学对评委进行测评——以第九届“步步高杯”全国青年歌手电视大奖赛(专业组)得分情况进行评估

对每一位评委 ,求他对每一位选手的打分和相应的平均分的积差相关系数 ,便可得到该评委的效标效度。该效度也就是对该评委的测评