结构振动试验转接器的设计及安装问题

一些产品及其相关部件在作振动试验时，由于产品的外形或特殊要求不能直接安装在振动台面上，需要通过特别设计的转接器（夹具）来进行连接，这种夹具实际上是一种附加结构，它作为台面与试件之间的中介，如设置不当将影响振动试验结果的可靠性。本文通过对某事例的分析与研究，从试验频带、允许误差、跟随条件以及安装共振频率等方面阐明与讨论了相关夹具的特性、设计原则与安装等问题。     

带限信号高频重建的一种新的正则外推算法

本文提出生种新的带限信号的外推方法，该方法能够很好地抑制噪声干扰，且计算复杂性较低，本文给出算法，证明了收敛性，最后给出了误差计算机实验结果。     

特低渗透油层含油饱和度的一种校正方法

松辽盆地北部扶杨油层属特低渗透油层，即使采用油基泥浆取心或密闭取心样品，束缚水饱和度也难以测准。蒸馏法试验表明，若试验温度低，则束缚水蒸发不彻底，实测含水饱和度偏低；若试验温度高，则容易造成岩样粘土矿物晶间水脱水，实测含水饱和度偏高，影响了储量计算精度。为搞清特低渗透油层流体蒸发特征，开展了蒸发率试验，试验过程是：将岩样洗油后重新饱和水，再在与蒸馏法试验相同的试验条件下测定蒸发的水量。试验结果表明，有效孔隙度越小，蒸发率越低。由于两个试验过程的蒸发率近似相等，用蒸发率试验可以模拟蒸馏法试验，由此推导出束缚水饱和度计算公式。应用该公式对榆树林油田进行测算，校正前后原始含油饱和度相差１２％以上，储量相差２０×１０６ｔ以上。图２（郭海莉摘）     

工艺系统刚度产生的误差原理与分析

根据对工艺系统受力变形的分析 ,阐述了工艺系统刚度对零件加工精度的影响 ,并简要提出了提高工艺系统刚度的办法     

A practical minimum distance method for syntax error handling

We present a method for recovering from syntax errors encountered during parsing. The method provides a form of minimum distance repair, has linear time complexity, and is completely automatic. A formal method is presented for evaluating the performance of error recovery methods, based on global minimum-distance error correction. The minimum-distance error recovery method achieves a theoretically best performance on 80% of Pascal programs in the weighted Ripley-Druseikis collection. Comparisons of performance with other error recovery methods are given.     

A geometry-based error estimation for cross-ratios

For choosing specific cross-ratios as 2D projective coordinates in various computer vision applications, a reasonable error analysis model is usually required. This investigation adopts the assumption of normal distribution for positioning errors of point features in an image to formulate the error variances of cross-ratios. Based on a geometry-based error analysis, a straightforward way of identifying the cross-ratios with minimum error variances is proposed. Simulation results show that the proposed approach, as well as a further simplified alternative, yield much better estimations of minimum error variances in terms of accuracy, cost, and stability compared with some other methods, e.g., the one based on the rule given by Georis et al. (IEEE Trans. Pattern Anal. Mach. Intell. 20 (4) (1998) 366). Some causes of the performance differences in the estimations are explained using a special configuration of point features.     

视频编码新标准H.264中抗误码技术的研究

介绍了视频编码新标准———H .2 6 4中采用的几种抗误码技术 ,基于这些技术 ,新标准确保了压缩视频流在接收端的恢复质量。     

网络分解法的误差分析

网络分解法是求解电大尺寸复杂结构电磁问题的重要方法之一,关于网络分解法误差分析的研究有着重要的理论意义和实用价值.本文给出了网络分解法的误差估计,并对于脉冲基函数转换成三角基函数的情况给出了三角基函数个数的最优公式,数值结果表明了分析的正确性.     

Remarks on the mean square tracking error

The purpose of this paper is to extend recent results of Ljung and Priouret to a more general class of regressors.     

贯彻食用盐新标准 做好食用盐质量检测

介绍了食用盐新国标制定的指导思想，新标准的特点及所修订的内容，指出为做好食用盐的质量检测要掌握和控制的技术要点，以保证和提高盐质分析结果的准确度，确保食用盐产品质量符合标准要求。