Type Synthesis of Two-Degrees-of-Freedom Rotational Parallel Mechanism with Two Continuous Rotational Axes

The two-rotational-degrees-of-freedom（2R） parallel mechanism（PM） with two continuous rotational axes（CRAs） has a simple kinematic model.It is therefore easy to implement trajectory planning,parameter calibration,and motion control,which allows for a variety of application prospects.However,no systematic analysis on structural constraints of the 2R-PM with two CRAs has been performed,and there are only a few types of 2R-PM with two CRAs.Thus,a theory regarding the type synthesis of the 2R-PM with two CRAs is systematically established.First,combining the theories of reciprocal screw and space geometry,the spatial arrangement relationships of the constraint forces applied to the moving platform by the branches are explored,which give the 2R-PM two CRAs.The different distributions of the constraint forces in each branch are also studied.On the basis of the obtained structural constraints of branches,and considering the geometric relationships of constraint forces in each branch,the appropriate kinematic chains are constructed.Through the reasonable configuration of branch kinematic chains corresponding to every structural constraint,a series of new 2R-PMs with two CRAs are finally obtained.

C^n-CONTINUOUS B-TYPE SPLINE CURVES WITH ITSLOCALIZATION INTERPOLATION AND APPROXIMATION

This paper presents a class of Cn- continuous B- type spline curves with some paramet- ric factors.The length of their local support is equal to4.Taking the different values of the parametric factors,the curves can become free- type curves or interpolate a set of given points even mix the both cases.When the parametric factors satisfy the certain conditions,the degrees of the curves can be decreased as low as possible.Besides,when all the parametric factors tend to zero,the curves globally approximate to the control polygon.

The Application of Numerical Characteristics to the Distribution Characteristics of Copper in the Liao River, China

The aim of the present investigation was to research the distribution characteristics of copper in water and sediment of the Liao River, China. The concentrations of copper in water and sediment showed significant difference at different sampling stations. The distribution characteristics of copper in water and sediment were obtained by using discrete and continuous numerical characteristics. The results indicated that the average concentrations of copper in water and sediment decreased slightly after its accumulation. While the deviations of the concentrations of copper in water and sediment from the expectation increased significantly after its accumulation. The skewness distributions of the concentrations of copper in water and sediment did not change much before and after its accumulation. The kurtosis distributions of the concentrations of copper in water and sediment decreased significantly after its accumulation. Therefore, the precise distribution characteristics of copper in water and sediment were obtained through the combination of the discrete and continuous numerical characteristics. .

Analysis of influencing factors on fine sediment flocculation in the Changjiang Estuary

Based on the test data in dynamic water and static water, the main factors, which influence the fine sediment flocculation, are analyzed with a gray model method of correlation theory. It is shown that the main influencing factors are water temperature, settling time, salinity, grain size, sediment concentration and current velocity according to the correlation coefficients. Among them, the salinity and the sediment grain size are critical type influencing factors (CrTIF); the settling time, the sediment concentration and the velocity are continuous type influencing factors (CoTIF); and the water temperature has the characteristics of both. When the critical values of CrTIF are reached or exceeded, the fine sediments will be flocculated, but values of CrTIF will not influence the settlement strength of floes. The influence of CoTIF is continuous. The values of the CoTIF will not only influence the occurrence of flocculation but also the settlement strength of the floes.

Three-Dimensional Generalized Inverse Matrix Rational Interpolation

In this paper, a three dimensional matrix valued rational interpolant (TGMRI) is first constructed by making use of the generalized inverse of matrices. The interpolants are of the Thiele type branched continued fraction form, with matrix numerator and scalar denominator. Some properties of TGMRI are given. An efficient recursive algorithm is proposed. The results in the paper can be extend to n variable.

2型糖尿病患者血糖漂移水平与动脉脉搏波速度的相关性研究

目的:研究2型糖尿病患者血糖漂移水平与动脉脉搏波速度的关系。方法:共入选82例2型糖尿病患者作为研究对象。所有研究对象应用自动脉搏波速度测定仪测定颈动脉-股动脉脉搏波速度(CFPw V);采用动态血糖检测系统(CGMS)及全自动生化分析仪进行检测,收集空腹血糖(FBG)、餐后2小时血糖(2hPG)、糖化血红蛋白(HbA1c)、血糖水平标准差(SDBG)、平均血糖波动幅度(MAGE)、最大血糖波动幅度(LAGE)、昼间血糖漂移幅度(MODD)等血糖参数。根据CGMS检测结果将82例2型糖尿病患者分为血糖低漂移组(47例)和血糖高漂移组(35例),比较两组中各血糖参数及CFPw V水平,计算两组动脉硬化发生率,并将各血糖参数与CFPw V进行Pearson相关性分析。结果:与血糖低漂移组比较,2hPG、SDBG、MAGE、LAGE、MODD、CFPw V在血糖高漂移组中升高(P<0.05);血糖高漂移组中动脉硬化的发生率高于血糖低漂移组(P<0.05);Pearson相关性分析分析显示2hPG、MAGE、LAGE、MODD与CFPw V相关(P<0.05)。结论:本研究中,82例2型糖尿病患者存在不同程度的动脉硬化;2hPG、MAGE、LAGE、MODD是2型糖尿病患者CFPw V升高的相关因素,提示血糖漂移进一步加重动脉硬化,参与动脉硬化的发生发展。应该重视对血糖漂移的控制,减少动脉硬化的发生率,延缓动脉硬化的发展。