半导体封装模具模腔偏错位原因分析

介绍了半导体封装模具偏错位种类,分析了偏错位缺陷产生的原因,并针对偏错位总结了几种相应的纠正措施、改善解决方案,指出应从模具设计、材料选择、模具温度设置调整、定位零件设计、总检与控制等各方面系统优化解决。     

A decision support methodology with risk assessment on prediction of terrorism insurgency distribution range radius and elapsing time: An empirical case study in Thailand

The objectives of this research are to design and develop a practical decision support methodology with efficient prediction tool and risk assessment analysis of a terrorism insurgency situation. The proposed methodology consists of two main parts as: (1) the prediction modelling and (2) risk assessment analysis. The Improvised Explosive Device (IED) incidents from 2007 to 2013 in the capital district of Yala province, the southern part of Thailand, are collected and generated to the methodology as a case study implementation. The proposed methodology is capable of indicating and illustrating the risk assessment prediction results of terrorism insurgency incidents. Furthermore, the demonstration of the Explosive Ordnance Disposal Mobile Unit (EODMU) based upon a Risk Assessment Radar Chart is investigated. In practical terms of applying the proposed methodology, the Thai Government can concentrate on a critical operation zone under a Risk Assessment Radar Chart, resulting in a more accurate operation and leading to a much lower number of casualties.     

Ф3．5m氟化氢反应炉的研制

采用设计院技术对无水氟化氢反应炉进行研制，克服筒体整体加工、动静密封配研、夹套的焊接、传动部分加工等难题，并针对研制过程中的关键技术难题，采取合理工艺措施，满足了反应炉的制造要求，为类似产品的制造提供借鉴。     

Thermo-mechanical fatigue resistance characterization and materials ranking from heat-flux-controlled tests. Application to cast-irons for automotive exhaust part

In a context where the mass, the cost and the mechanical strength of materials must be jointly optimized, it is necessary to have experimental data quickly available and sufficiently robust to make efficient conception choices. For thermomechanical fatigue, standard tests usually allow comparing material for the same temperature and strain ranges although differences in thermal properties such as conductivity or thermal expansion could make significant deviations when the same thermal flux is applied particularly for structure with forced heat flux operating regimes. A new protocol is then proposed in order to compare the specific resistances of metallic materials against thermomechanical fatigue. It can easily rank materials according to their lifetime under thermomechanical loadings where strain range and temperature amplitude are determined by the heat flux applied on an industrial part. The method is based on a complete numerical analysis to determine experimental loading conditions as a temporal evolution of temperature and mechanical strain representative of thermomechanical loading observed in TMF critical areas for the part. TMF tests on hollow specimens are carried out to rank the materials: temperature and strain amplitude are different for each alloys whereas heat flux is identical. A materials ranking list based on TMF resistance is then determined according to their lifetimes under “heat-flux-controlled” tests. The method is tested for exhaust parts and demonstrates the superiority of some cast irons over others, whereas the intrinsic isotherm mechanical properties suggested an alternative classification. The obtained ranking is confirmed by experimental tests on industrial structures.     

电梯机械内部零件老化过程与检验

本文将介绍电梯机械内部零件的定义、分类以及危害,并通过分析电梯零件老化的原因及老化过程,提出检验方法.     

Analysis of surface roughness parameters digital image identification

The article analyses some surface roughness parameters of metal parts determining the ability of the surface of digital image identification, covariance functions and Wavelet’s wave theory. Expressions of covariance functions are formed using random functions, made by spreading digital image pixel arrays by columns in the form of individual vectors. The digital images used for research may vary in scale, because the frequencies of colour waves with individual pixels remain constant in the images, therefore, the image change does not influence the scale in computing covariance functions. The colour spectrum of RGB format was applied to identify the surface images of the parts. There was analysed the influence of individual RGB colour tensor components on the estimates of digital image covariance functions. The identity of digital images was evaluated by the change of correlation coefficient values in the range of RGB colours. The software was applied to compute the above process.     

大跨度拱形钢管桁架制作安装实例介绍

本文简要介绍了淮河防洪除涝减灾实体模型基地试验大厅工程大跨度钢管桁架的施工和施工方案的选择,重点分析了分件制作、现场拼装、双机抬吊、桁架整体就位主要过程的施工要点及注意事项.     

厚板件修边精冲模设计

分析了厚板件提高断面精度的工艺方法,并介绍了修边精冲模结构、工作过程及模具设计要点。该模具的投产保证了厚板件支挡块的外形尺寸及性能要求,同时产能提升6倍以上。     

Hierarchical Implicit Shape Modeling

In this paper, a new hierarchical approach for object detection is proposed. Object detection methods based on Implicit Shape Model (ISM) efficiently handle deformable objects, occlusions and clutters. The structure of each object in ISM is defined by a spring like graph. We introduce hierarchical ISM in which structure of each object is defined by a hierarchical star graph. Hierarchical ISM has two layers. In the first layer, a set of local ISMs are used to model object parts. In the second layer, structure of parts with respect to the object center is modeled by global ISM. In the proposed approach, the obtained parts for each object category have high discriminative ability. Therefore, our approach does not require a verification stage. We applied the proposed approach to some datasets and compared the performance of our algorithm to comparable methods. The results show that our method has a superior performance.     

Investigations for indications of deliberate blasting on the front bulkhead of the ro-ro ferry MV ESTONIA

The roll-on-roll-off passenger ferry MV ESTONIA sank during the night of 28 September 1994 in the Baltic Sea. In October 2000, divers recovered two palm-sized test pieces from the front bulkhead of the wreck. The investigators analysed these specimens to determine whether there were any indications of deliberate blasting. Since the wreck had been submerged for almost six years, it was clear that chemical traces would not be present on the surfaces of the test pieces. Therefore, the investigators performed comparative tests on shipbuilding steel to find a microstructural criterion that exclusively characterises a blast. The shipyard Jos. L. Meyer, Germany, had built the ESTONIA and supplied shipbuilding steel plates similar to that used for building the vessel in 1979/1980. The comparative tests comprised mechanical tests, shot peening tests and blasting tests using different explosives. Testing demonstrated that blasting always formed twinned ferrite grains in the microstructure over the whole cross-section of each of the 8 mm thick comparative plates. Although one of the original test pieces of the ESTONIA showed deformation twins, this was only confined up to 0.4 mm underneath the surfaces and not spread over the whole cross-section. Comparative shot peening tests produced the very same pattern of subsurface deformation twins. Therefore, the twins detected in the microsection of the test pieces of the ESTONIA wreck traced back to the shot peening process performed by the shipyard in 1979/1980 and not to a deliberate blast.