基于协同设计的CAD/CAPP/CAM集成方法

本文从协同开发环境CAD／CAPP／CAM集成特点人手,分别研究探讨了CAD／CAPP／CAM集成基本方法和关键技术,构建了协同开发环境中CAD／CAPP／CAM集成系统的体系结构。     

定制化CAD/CAPP/CAM集成系统研究和开发

随着CAD／CAPP／CAM集成系统在企业的应用，企业为了提高产品开发效率和满足用户个性化需求，急需对CAD／CAPP／CAM集成系统的定制化进行研究。本文探讨了定制化CAD／OAPP／CAM集成系统的设计思想和实现方法，在开放的统一产品信息模型基础上，设计了基于PDM的定制化CAD／CAPP／CAM集成系统框架，并对实现该框架所涉及的定制内容及其实现技术进行了深入研究。给出了在PDM商业软件Teamcenter环境下所实现的CAD／CAPP／CAM定制集成的实例。     

CIMS环境下MRPⅡ与CAD/CAPP/CAM集成系统

MRPⅡ是现代制造企业进行现代管理的科学方法之一。实现MRPⅡ与CAD／CAPP／CAM集成能降低库存成本，提高生产效率。本文介绍了CIMS环境下MRPⅡ与CAD／CAPP／CAM集成系统结构、集成方案及其技术上实现的方法。该集成系统的实现能够缩短设计周期、提高生产效率和生产质量。     

基于PDM的CAPP/CAM集成技术的研究

对基于PDM的CAPP／CAM集成技术进行了研究。文章首先提出了基于PDM的CAPP／CAM集成系统的框架结构，随后分析了CAPP／CAM集成系统的信息流程，最后给出了零件的加工仿真模型以实现集成。     

面向制造的CAD／CAPP／CAM集成系统的研究

CAD／CAPP／CAM集成是CIMS工程中重要技术单元。在分析CAD／CAPP／CAM信息集成方式的基础上,以面向制造的设计为背景,探讨了以工程数据库为核心的面向制造的零件CAD／CAPP／CAM集成系统的体系结构及其实现方法。给出一个轴类零件CAD／CAPP／CAM集成系统实例,并对其主要组成模块进行了较为详细的分析。     

基于特征相似性的船用柴油机关键件CAD／CAPP／CAM集成技术

对不同型号的船用柴油机关键件相似性进行分析,总结出船用柴油机关键件的相似加工特征、相似加工工艺及加工刀轨。基于特征相似性,研究了船用柴油机关键件CAD／CAPP／CAM集成技术,建立了特征加工模板库,通过特征加工模板的动态组合,实现了CAD／CAPP／CAM集成系统中特征加工模板的共享与重用,并通过应用实例对其进行验证。该系统能解决新的相似加工对象在CAD／CAPP／CAM集成系统工艺推理、刀轨规划等过程中的重复操作,降低企业在船用柴油机关键件制造过程中的重复性劳动及增强船用柴油机关键件CAD／CAPP／CAM集成系统的通用性,对解决其他类型复杂零件的CAD／CAPP／CAM集成系统中相似性利用问题也有很好的借鉴意义。     

基于Pro/NC的CAD/CAPP/CAM集成探讨

在Pro／NC平台上对CAD／CAPP／CAM的集成进行了研究,给出了集成系统的结构框架、关键集成技术和应用实例,一定程度上简化了形成刀位加工文件时所需要的繁琐的人机交互操作。     

CAD与CAPP的信息集成

一、概述CAD与CAPP信息集成是指CAD和CAPP之间的信息提取、交换、共享和处理。CAPP是连接CAD／CAM的桥梁，是实现CIMS的关键技术之一。而要实现CAD／CAM的集成，首先必须实现CAD／CAPP的集成，即实现CAD／CAPP之间的信息共享。目前，CAD／CAPP信息集成问题已成为国内外学者关注     

基于PDM的CAD／CAPP／CAM集成技术研究。

在CAD／CAPP／CAM集成中,数据的同步更新和存储管理是影响系统集成的主要问题。就CAD／CAPP／CAM集成原理、基于PDM集成的关键技术进行了探讨,并提出了一个基于PDM的CAD／CAPP／CAM集成模型,有效地解决了系统集成中的数据管理问题。     

CAD/CAPP/CAM/CAE系统集成关键技术及其实现方法

在介绍CAD／CAPP／CAM／CAE系统功能及组成的基础上，分析了该系统的集成关键技术及实现方式。     

Cylindrical specimens for KIC of rocks

Stress intensity factors for pairs of diametrically opposite radial cracks on the inside of a jacketed pressurized hole in a thick cylinder have been calculated by using finite element technique. Burst tests on thick cylinder rock samples under above conditions have been performed and the K_IC values for Antrim Shale and Limestone determined. The method is very convenient for rocks whose samples are often available in form of cylindrical bars drawn as cores from underground drilling.     

GT/CAD/CAPP/PDM/ERP系统集成研究

研究ETO生产方式下以成组技术为基础的CAD/CAPP/PDM/ERP的集成方法,包括面向CAD/CAPP/PDM/ERP的集成的成组信息编码,基于成组编码的CAD/PDM集成、CAPP/PDM集成和PDM/ERP集成.提出了基于成组技术的CAD/CAPP/PDM/ERP集成框架,研究了贯穿于CAD、CAPP、PDM与ERP系统的统一的成组编码方案和信息编码方案.     

Electron and light microscopy studies on the domain structures of Zn3B7O13Cl, Zn3B7O13Br and Zn3B7O13I ferroic boracites

The domain structures of Zn₃B₇O₁₃Cl, Zn₃B₇O₁₃Br and Zn₃B₇O₁₃I boracite single crystals were studied by means of polarized light in conjunction with electron microscopy. Single crystals of the three compositions were grown by chemical transport reactions in closed quartz ampoules, at a temperature of 900 °C and were examined by polarizing optical microscopy (PLM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For both PLM and SEM, the same as‐grown samples were used without having to resort to metallization of the crystal faces. For TEM the single crystals were crushed and mounted on holey carbon films. Comparative electron microscope images were useful for revealing the domain structure of these ferroelectric/ferroelastic materials previously observed between the crossed polars of an optical microscope. X‐ray diffraction analysis of the pulverized crystals was performed for this triad of halogen boracites containing zinc as a common metal.     

Analysis of the Rk surface roughness parameter proposals

European manufacturers have proposed a set of surface roughness parameters based on an examination of the variation in slope of the bearing ratio curve of a surface profile. It is shown, that the proposed procedure provides no useful information, and indeed is misleading, since the bearing ratio curve of even a normally-distributed random surface profile exhibits the expected variation in slope when plotted on rectangular coordinates. On the other hand, the desired information is readily obtained by a similar examination of the cumulative height distribution of a surface profile (the unity complement of the bearing ratio) when it is plotted on normal probability coordinates.     

基于太赫兹光谱的人参和西洋参鉴别

为了快速区分人参和西洋参，依据两者所含的人参皂苷在太赫兹波段具有不同指纹光谱，提出了一种基于人参皂苷的太赫兹光谱鉴别人参和西洋参的方法。采用MATLAB软件识别人参和西洋参的太赫兹光谱，同时根据太赫兹光谱特征并通过标准的主成分分析(PCA)区分出人参、西洋参。实验结果表明，基于太赫兹光谱的主成分分析可精确区分出人参、西洋参，并且还可以应用于其他类似物质的区分中。     

永磁同步电机积分滑模观测器控制

对永磁同步电机观测器控制进行研究,针对传统滑模观测器存在控制精度低、系统抖振较大的不足,设计了一种永磁同步电机积分滑模观测器控制。积分滑模控制具有控制精度高、系统抖振小的特点。积分滑模观测器可以有效提高电机控制精度,增强控制系统抗干扰能力。采用饱和函数代替符号函数进行滑模控制律设计,降低控制系统固有抖振,使滑模控制动态性能提高。通过仿真验证了积分滑模观测器控制策略的可行性。     

Characterization of cast Al86Mn3Be11 alloy

An Al₈₆Mn₃Be₁₁ alloy cast into copper mould was subjected to metallographic investigation. The as-cast microstructure consisted of a quasicrystalline icosahedral phase (i-phase), Be₄AlMn phase and, occasionally, a hexagonal phase. Al-rich solid solution represented the dominant phase. The chemical compositions of phases were determined using AES. The composition of the Be₄AlMn slightly deviated from the stoichiometric composition, whereas the composition of the i-phase was approximately Al₅₂Mn₁₈Be₃₀, containing an appreciable amount of Be. The average composition of the hexagonal phase was Al₆₆Mn₂₁Be₁₃. Deep etching and particle extraction provided a deep insight into the three-dimensional morphology of the i-phase and the hexagonal phase, whereas Be₄AlMn was slightly attacked by the etchant. The i-phase was present predominantly in the form of dendrites and a rodlike eutectic phase. The hexagonal phase was primarily in the form of hexagonal platelets, whereas Be₄AlMn was rather irregular in shape. The morphology of the i-phase can be explained by predominant growth in 3-fold directions and the lowest energy of the 5-fold planes, leading to the faceting and adopting a pentagonal dodecahedron shape. The brightnesses of phases in the backscattered electron images were rationalized by determining their backscattering coefficients. TEM investigation showed considerable phason strain in the i-phase, and the polycrystalline nature of the Be₄AlMn phase.     

Investigation on the impact behavior of Al2O3-SiC-MgO nanoceramic/metal laminated composite

Lightweight laminated composites containing a ceramic front layer and a metallic backing layer were used in order to protect people, moving equipment, and mobile vehicles from high velocity impact and the increased mobility of mobile vehicles. In this study, by adding10 vol% SiC and 500 ppm MgO nanoscale particles on the microstructure of Al ₂ O ₃ matrix and applying optimum sintering conditions, ceramic performance against high-speed projectile impact was improved. To perform this investigation, a number of target samples with two different types of front layers (alumina and Al ₂ O ₃-SiC-MgO nanocomposite ceramic) were produced. Impact tests were conducted on these samples using 7.62 mm projectiles with a velocity of 820 ± 15 m/s. The amount of bulge and bending of the backing layer caused by impact tests was measured. The results of the impact tests on the samples made of Al ₂ O ₃-SiC-MgO nanocomposite ceramics and alumina were also compared and analyzed. The results indicate that the substitution of Al ₂ O ₃-SiC-MgO ceramic layer — which is proffered in this paper — instead of pure alumina ceramic layer, decreases the areal-density of the samples by at least 30% and improves mechanical properties by about a 60% increase in flexural strength and 100% growth of the energy distribution factor, which impressively increases impact energy absorption.     

Electron microscopy of crack/particle interactions in Al2O3/SiC nanocomposites

Crack/particle interactions in alumina/silicon carbide nanocomposites have been investigated by scanning electron microscopy and transmission electron microscopy, with cracks induced by Vickers microindentation. Intergranular cracks are frequently deflected into grains by SiC particles on grain boundaries inclined to the average direction of crack propagation. This mechanism is proposed to explain the change in the fracture mode from intergranular fracture for monolithic alumina to predominantly transgranular fracture for the nanocomposites. Neither stress-induced microcracking around SiC particles nor significant crack deflection by intragranular particles was found to occur in the nanocomposites. It is argued that an addition of nanoparticles may not be a promising approach for increasing the toughness of alumina.     

Near-field second harmonic imaging of the c/a/c/a polydomain structure of epitaxial PbZrxTi1–xO3 thin films

Near-field optical second harmonic microscopy has been applied to imaging of the c/a/c/a polydomain structure of epitaxial PbZr _x Ti_{1– x} O₃ thin films in the 0 <  x  < 0.4 range. Comparison of the near-field optical images and the results of atomic force microscopy and X-ray diffraction studies show that an optical resolution of the order of 100 nm is achieved. Symmetry properties of the near-field second harmonic signal allow us to obtain good optical contrast between the local second harmonic generation in c- and a-domains. Experimentally measured near-field second harmonic images have been compared with the results of theoretical calculations. Good agreement between theory and experiment is demonstrated.