超声多普勒方向性血流信息的提取

本文以窄带随机信号理论为基础，对方向性血流信息提取的原理作了有别于文献报导的分析，并指出了时城后处理方法在提取方向信息中存在的问题。此外，本文还就在前置放大器中使用丙类放大器对谱分析结果所造成的失真作了分析。在上述理论分析的基础上介绍了新试制的方向性多普勒血流计原理框图。     

价格系统及其稳定性研究

本文基于产品的销售额和毛利率,从生产和市场的角度出发,提出了一个新型的部门产品价格模式——经济部门系统的价格模型。该模型表明报告期的产品价格向量Ｐ（ｔ＋１）可以表示成两个向量的凸组合之和,其中一个是基期单位产品物耗成本ＡＴ（ｔ）Ｐ（ｔ）与报告期单位产品物耗成本ＡＴ（ｔ＋１）Ｐ（ｔ＋１）的凸组合,即Θ＾（ｔ）ＡＴ（ｔ）Ｐ（ｔ）＋Ｅ＾（ｔ）ＡＴ（ｔ＋１）Ｐ（ｔ＋１）;另一个是基期单位产品和报告期单位产品在报告期销售所获毛利δ１（ｔ＋１）和δ２（ｔ＋１）的凸组合,即Θ＾（ｔ）δ１（ｔ＋１）＋Ｅ＾（ｔ）δ２（ｔ＋１）,这里Θ＾（ｔ）≥０,Ｅ＾（ｔ）≥０,Θ＾（ｔ）＋Ｅ＾（ｔ）＝Ｉ（单位矩阵）,Ａ（ｔ）和Ａ（ｔ＋１）分别是两期的实物型投入产出表的直接消耗系数矩阵。在基期和报告期的生产技术结构一致和其它假定条件下,我们给出了该系统稳定的四个充分必要条件。最后考察了一个特例,提出了临界平均工资率ＲＣ的概念,证明了如果全社会平均工资率Ｒ＜ＲＣ,则该价格系统是稳定的。     

The Influence of Modifications of Latch Needle on Impact Forces Between Cam and Needle

On the basis of a mechanical model, cam-to-needle impact force during weft knitting is analyzed and some needle parameters related to the peak impact forces are presented. An experimental method is built to measure dynamic parameters of needle. Contrast tests of impact forces with different needles show that needle modifications Influence apparently needle parameters and peak impact forces.     

The Mesh Efficiency of the Planetary Mechanism of 2K - H[D] Style

The mesh efficiency of the planetary mechanism of 2K - H[D] style is discussed. It comes to a new formula. Usually, an approximate value is taken as the mesh efficiency of a planetary mechanism. If the formula is used, the theoretical value of mesh efficiency can be gotten. The theoretical mesh efficiency can help engineers to know the true efficiency of 2K - H[D] style when it runs. The mesh efficiency serves the transmitting efficiency of a planetary mechanism.     

Research on Tearing Property of Reinforced Plastic Film with Bi - axial Warp Knitted Fabric Skeleton

The specification of laid-in and warp yams,thedensity of fabric and the specification of groundyam are of great importance when the bi-axialwarp knitted fabric being knitted.In this paper,the tearing property of the reinforced plastic filmwith bi-axial warp knitted fabric skeleton istested and analyzed.The resuits show thatamong the three factors,the specification of laid-in and warp yam has the greatest influence onthe tearing strength of the reinforced plastic film,while the rest of them has secondary and lesseffect respectively,and there is exponential re-lation between the tearing strength of the rein-forced plastic film and the number of yams in thedirection of force.     

Study on the Model of Thermal Channel Spinning Process for PET Polymer

A mathematical model to describe the TCS process inPET high-speed melt-spinning is established.The de-velopment of crystallinity,molecular orientation andmorphological features of high-speed-spun PET fiberin TCS process is investigated at take-up speeds rangingfrom 3600-4400 m/min and thermal channel tempera-tures ranging from 160-200℃ by simulation.The pro-files of tensile force,running velocity,temperature,bi-refringence,crystallinity and diameter in the TCS spin-line for various process conditions are obtained.Thepredicted results using this model are compared with themeasured crystallinty,diameter and birefringence.Theresults indicate that they are in fairly good agreement.The"necking point"in the TCS spinline can be predictedby this model,and its position changes with the corre-sponding process parameters such as take-up speed andthermal channel temperature.It is found that the neck-ing point moves towards the spinneret when the take-upspeed or the thermal channel temperature increases.     

旧路加宽综合处治技术的模型试验研究

通过旧路加宽室内模型试验可以获得新旧路基间的变形和刚度差异,以及经过加筋处治的路基内压力分布特点,且室内疲劳加载试验可以较有效地测试路面结构内的应力应变状态。试验结果可以用来验证旧路加宽综合处治技术的有效性和可靠性,并可对理论分析结果进行验证。     

变形系数相关的最小二乘匹配算法

对在图像匹配中被广泛使用的最小二乘算法进行了改进．最小二乘算法精度高,但收敛速度很慢．根据图像中除少数高度变化不连续的区域外,大多数区域的变形参数都是连续变化且平缓这一特点,在最小二乘算法的迭代过程中,变形参数初始值视情况取前面的结果．实验表明,这一改进大大提高了最小二乘匹配算法的计算速度,同时保持了其精度和匹配率     

异构计算的一种可移植编程模型及实现

介绍了异构计算的一种编程模型．该模型处理的对象是任意非一致的求解任务映射到任意非一致的系统结构上．文中分别给出了任务图的分簇算法,系统图的分簇算法和映射算法及实例．利用该模型可设计出可移植的并行程序,然后调度到可动态配置的异构计算机组织上运行     

非绝热量子晶格涨落效应作用下准一维电-声子系统的带间跃迁光吸收谱

通过正则变换和位移变换引进电－声子散射函数,并采用ＨＦ平均场近似方法,研究非绝热条件下量子晶格涨落对准一维电－声子系统带间跃迁光吸收谱的影响,得到了与实验观测结果相符合的无反平方根奇异并具有能隙内带尾的光吸收系数。