Proficiency test for effective area determination of a pneumatic pressure balance in Mexico

A pneumatic pressure proficiency test for effective area determination of a pressure balance was performed among 4 accredited calibration laboratories in Mexico. CENAM provided the reference values (making initial and final calibrations) and was the pilot laboratory. The Mexican Accreditation Entity (ema) collaborated. The participants calibrated, by cross floating, a Wika pressure balance model CPB 5000 with accuracy class 0.015% of the reading in the range 0.7–7 MPa. The calibration pressures were 0.7, 1.4, 2.1 3.5, 4.2, 5.6 and 7.0 MPa. For A₀ and A_e, the normalized error equation was used to compare the results of the laboratories with CENAM’s reference values. The results obtained were satisfactory (E_n did not exceed the compatibility limit, −1 ⩽ E_n ⩽ 1).     

国家一级金矿石化学物相分析标准物质定值测试

武警黄金测试中心参加5个金矿石化学物相分析标准物质(GBW07189-GBW07193)定值测试工作,金矿石化学物相分析中测定游离金、连生体金、硫化物中金、其他矿物中金含量均取得满意的结果与公布的标准值基本一致。     

Hydrodynamic analysis of chemical mechanical polishing process

Chemical Mechanical Polishing (CMP) refers to a material removal process done by rubbing a work piece against a polishing pad under load in the presence of chemically active abrasive containing slurry. The CMP process is a combination of chemical dissolution and mechanical action. The mechanical action of CMP involves hydrodynamic lubrication. The liquid slurry is trapped between the work piece (wafer) and pad (tooling) forming a lubricating film. For the first step to understand the mechanism of the CMP process, hydrodynamic analysis is done with a semiconductor wafer. Slurry pressure distribution, resultant forces and moments acting on the wafer are calculated in typical conditions of the wafer polishing, and then nominal clearance of the slurry film, roll and pitch angles at the steady state are obtained.     

A kinematic analysis of disk motion in a double sided polisher for chemical mechanical planarization (CMP)

Double sided polishers are commonly used for industrial applications, such as lapping of silicon substrates and chemical mechanical planarization (CMP) of rigid disks. Whereas a kinematic analysis of a single sided polisher, extensively used for IC wafer CMP, is well known, available sources of such an analysis are limited for a double sided polisher, due to its more complicated design.The present work demonstrates a kinematic analysis for obtaining trajectory and relative velocity of a single location on a work piece during double side polishing. Relative velocity is used to calculate travel distance to be compared with the amount removed experimentally obtained. This paper presents mathematical derivation of the analysis and its effectiveness/limitations in conjunction with comparison between the analytical and experimental results.     

SISO extended predictive control: implementation and robust stability analysis

The proposed algorithm of extended predictive control (EPC) represents an exact method for removing the ill-conditioning in the system matrix by developing a unique weighting structure for any control horizon. The main feature of the EPC algorithm is that it uses the condition number of the system matrix to evaluate a single tuning parameter that provides a specified closed-loop response. Robust analysis demonstrated that EPC is more robust in comparison with move-suppressed and m-shifted predictive controllers in all aspects of process variation in gain, delay, and time-constant ratios. Tuning of EPC is effective and simple since there is a direct relationship between closed-loop performance and its tuning parameter.     

小波分析在手表走时测试中的应用

由于手表检测的表音信号中含有大量的噪音信号,这给手表的检测带来了很大困难.简述了小波消噪的基础理论,论述了小波分析在手表走时测试中的具体应用.试验及分析结果表明,在提取表音信号时采用小波分析方法,很大程度上消除了噪音的影响,提高了手表走时测试的精度.     

Using coherence factor to improve the quality of reflector images in ultrasonic testing

When running ultrasonic testing, it is possible to analyze reflector images that have been restored by the method of digital focusing with an antenna (DFA). To improve the quality of the reflector images, one can use a coherence factor (CF) or a sign coherence factor (SCF) obtained from the calculated delay times instead of counting echo signals. The images obtained with the calculation of the coherence factor make it possible to increase the signal-to-noise ratio and front resolution. It has been demonstrated by numerical and model experiments that reconstructing the CF- and SCF-images of reflectors is efficient when registering echo signals by both ordinary and thinned (TAA) antenna arrays, in which the distance between neighboring elements is much greater than the wavelength.     

Hurwitz stability analysis of fractional order LTI systems according to principal characteristic equations

With power mapping (conformal mapping), stability analyses of fractional order linear time invariant (LTI) systems are carried out by consideration of the root locus of expanded degree integer order polynomials in the principal Riemann sheet. However, it is essential to show the left half plane (LHP) stability analysis of fractional order characteristic polynomials in the s plane in order to close the gap emerging in stability analyses of fractional order and integer order systems. In this study, after briefly discussing the relation between the characteristic root orientations and the system stability, the author presents a methodology to establish principal characteristic polynomials to perform the LHP stability analysis of fractional order systems. The principal characteristic polynomials are formed by factorizing principal characteristic roots. Then, the LHP stability analysis of fractional order systems can be carried out by using the root equivalency of fractional order principal characteristic polynomials. Illustrative examples are presented to explain how to find equivalent roots of fractional order principal characteristic polynomials in order to carry out the LHP stability analyses of fractional order nominal and interval systems.     

几种数据协调方法在浆纸平衡系统中的应用

若信息管理系统直接利用带误差的现场数据,将造成管理失误和决策偏差。因此,必须根据浆平衡,对各类浆池与纸机的原始数据进行过失误差处理和数据协调计算。该文比较了浆纸平衡模型中,不确定模型的数据协调法,基于统计检验的协调法及用Matlab优化工具协调的应用结果,其中不确定模型的数据协调方法具有良好的适应性及数据协调能力。     

基于Hibernate的业务数据统计分析的设计和实现

本文首先阐述了针对电子商务系统的业务数据统计分析的意义,随后展开对业务数据处理过程中的"数据提取","数据计算"和"数据表示"三个阶段的讨论,着重介绍了当前流行的B/S软件模式下,基于Hibernate的业务数据统计分析的设计和实现,最后就性能方面提出了一些改进的方法。     

The boundary fitted coordinate method to improve the numerical analysis of electron optical systems

This paper illustrates some of the advantages of using the boundary fitted coordinate technique in the numerical simulation of electron-optical systems. The boundary fitted coordinate technique can be used as an automatic mesh generator for the finite-element solution of field distributions, while at the same time allowing for the possibility of high order inter-polation on the mesh, typically required for the accurate plotting of electron trajectory paths. For the finite difference method of solving field distributions, the boundary fitted coordinate method can generate regular meshes, which fit curved shaped boundaries.     

精密光电测试转台热特性仿真分析

本精密光电测试转台用于高精度星敏感器的地面标定检测系统,其置于地面模拟空间环境中,要求其在恶劣的模拟空间环境中具有极高的精度.为了研究精密转台在模拟的空间高、低温真空环境中的变形特点及工作精度,首先分析了转台所处的高、低温真空环境的特点,给出了转台在高、低温真空环境中的主要传热途径,然后合理地选择了转台材料并设计了转台的机械结构,最后应用ANSYS有限元分析软件对转台做了热-结构耦合仿真分析.通过仿真分析,得到了转台在两个极限温度(-60℃和90℃)环境中达到热平衡时的温度变化特性和整体变形量,进而得出了变形对转台在高、低温真空环境中精度的影响.结合对转台的使用精度要求,对转台进行了结构优化设计,最终使转台达到了所需要的工作精度要求.     

近红外显微图像的主成分法图像处理

介绍主成分分析算法在近红外显微图像分析中的应用,用该方法成功地提取出样品成分相关特征信息,并通过不同主成分的得分图像来描述样品的显微结构特征和特定化学成分分布。     

Bivariate analysis of complex vibration data: An application to condition monitoring of rotating machinery

The problem of the robust definition of the acceptance regions in condition monitoring of the vibrations of rotating machinery is related to the more wide field of the analysis of bivariate data. Traditional parametric techniques and innovative nonparametric methods based on the statistical concept of the data depth are presented and critically examined in the paper. The performances with respect to the robustness in the estimation of the acceptance regions are analysed by means of experimental cases of real rotating machinery of a power plant.     

高度自动化的机械制造过程控制方法

现代高度自动化的生产模式对机械制造过程的控制方法提出了新的要求。综合运用聚类分析和非参数检验的方法，结合传统的统计过程控制手段，提出了适用于多品种、大批量的高度自动化机械制造过程控制框架。通过实证研究，验证了方法的可操作性和实际效果。     

An optimistic robust optimization approach to common set of weights in DEA

Data envelopment analysis models allow decision making units to select the weights of inputs and outputs that are the most advantageous for calculating efficiency scores. Common set of weights make a basis for comparison and ranking all decision making units under an identical condition. In this paper, first we give the robust counterpart of the CCR model in envelopment form and show that it is the same as the optimistic robust counterpart of the multiplier form of the CCR model. Then the robust solutions for common set of weights under interval uncertainties are calculated using robust efficiency scores of units considering as ideal solutions. On two numerical examples, the performance of the new approach is compared with the approach developed by Omrani (2013) showing that it gives more reliable and better solutions.     

铁路提速客车轴承的台架运转性能试验分析

通过台架试验的温升对比数据分析和分解检查,验证了铁路提速客车轴承设计的正确性,可完全满足我国铁路提速客车运用的需要,可以为装车试验做充分的准备。     

在化工机械行业中实施绿色制造的策略

分析了绿色制造思想的背景，阐述了其内涵及发展趋势，指出了在化工机械中开展绿色制造的必然性，并探讨了在化工机械行业中实施绿色制造应采取的策略。     

基于灰关联分析的焊缝超声检测缺陷类型识别

本文提出了一种以灰关联度为测度识别焊缝缺陷类型的方法,并以夹渣、气孔、未焊透、未熔合4种焊缝常见缺陷为对象,对20个实际焊缝样本进行识别计算,并与射线检测结果对比.结果表明,该方法正确识别率达93.7%,具有较好的识别效果.