基于UG平台的塑料模具CAD/CAM系统的设计与制造

论述了塑料模具CAD/CAM系统的特点,分析了塑料模具CAD/CAM系统的功能模块和结构,介绍了三维实体CAD/CAM软件UG的功能,以及采用UG作为开发模具的平台,建立实用的塑料模具CAD/CAM体系.     

CAD/CAM在模具设计与加工中的关键技术

随着模具工业的发展,快速、高效、精密成为模具设计的基本要求。传统的主要依靠技术人员的经验和操作技能来进行模具设计与制造已不能为满足现代模具设计与制造要求,随着制造业信息化时代的到来,现代制造技术快速发展,各种CAD/CAM(Computer-Aided Design/Computer-Aided Manufacturing)软件在工业设计领域得到了广泛的应用,CAD/CAM技术应用于模具设计与加工成为模具发展的必然趋势。探讨了CAD/CAM软件在模具设计制造中应用过程以及一些软件使用注意事项和技巧。以Pro/E和MasterCAM软件在注塑模具中的应用为例就CAD/CAM软件在模具设计与加工中的关键技术进行探讨。提高了零件的制造精度和模具设计质量,缩短了模具设计周期。CAD/CAM一体化技术使模具设计制造更加便捷方便。     

实用化注塑模CAD／CAE／CAM系统HSC2.0

注塑模CAD/CAE/CAM技术自80年代以来已逐渐进入实用化.其中,注塑模CAD/CAM的重点在于注塑制品的造型、模具结构设计、图形绘制和数控加工数据的生成.注塑模CAE主要用来指导和预测模具在方案构思、设计和制造中的行为.华中理工大学模具技术国家重点实验室长期从事注塑模结构设计及注塑流动、冷却模拟软件的研究开发,最近成功地开发出实用化注塑模CAD/CAE/CAM系统HSC2.0.     

在第二届全国电子信息应用展览会上我校一项成果获优秀奖

5月19日至5月25日,第二届全国电子信息应用展览会在北京召开.我校参加了本次大会CAD展的展出.其中,模具CAD/CAM系统获得本次展览会优秀奖.我校同时参展的项目还有机一系CAD中心的集成机械CAD制造系统.模具CAD/CAM系统是由机二系注塑成形模拟与模具技术实验室承担完成的“七五”项目.它包括注塑模CAD/CAM/CAE和冷冲模CAD/CAM.注塑模CAD/CAM/CAE是在微机386上开发的,专     

基于UG的密封端盖虚拟制造研究

以UG 6.0为基础,进行密封端盖的3D建模。在UG MoldWizard下,完成密封端盖的注塑模具设计,实现对型腔和型芯的3D零件的创建。运用UG/NC对模具型芯进行加工刀路设计,模拟其加工过程。利用UG系统的后置处理,将刀具轨迹转化为适合数控加工的NC程序。提高了模具设计质量、产品制造质量,缩短了设计、制造周期。利用3D实体建模与CAM刀位轨迹源文件数据实时交换,实现设计、制造一体化。     

基于CAD／CAM在模具制造中应用的研究

在模具设计与制造中，应用UG、Pro-Engineer、Cimatron、Master CAM等CAD／CAM软件进行绘图、设计计算、CNC程序设计，可提高造型设计的准确性、减少设计及产品试制费用、节省材料、降低模具产品成本。     

陶瓷模具CAD/CAM系统

由于传统陶瓷模具设计制造过程漫长且复杂,无法满足日益激烈的市场竞争要求。结合先进制造技术,本文提出了陶瓷模具CAD/CAM系统。并对系统中反求工程、陶瓷模具虚拟设计及模具快速制造等关键技术进行研究。采用陶瓷模具CAD/CAM系统可以提高资源的利用率和设计效率,缩短产品开发周期,降低制造成本,同时也能提高企业对市场的快速响应能力。     

模具现代制造技术

该文分析了我国模具制造技术与国外的差距、模具现代制造技术的发展方向,集中介绍了模具现代制造技术中的核心技术:模具CAD/CAM、快速模具制造RT。对模具CAD/CAM、快速模具制造RT发展趋势进行了展望。     

面向个体的鞋类CAD/CAM技术研究

在了解和分析了国内外鞋类设计制造现状的基础上,说明了面向个体鞋类CAD/CAM技术研究的必要性,提出以足部CT图像建立的人类足部骨骼模型为参考构建的鞋楦模型的方式,利用三维CAD/CAM软件Pro/Engineer（简称Pro/E）进行参数化鞋楦设计的方法。最后以所得到的鞋楦为参考设计了一套注塑拖鞋的模具并以其中一个元件为例,利用Pro/E的Pro/NC模块生成其数控加工代码。效果令人满意。     

论CAD/CAM技术在提高刀具制造精度中的作用

本文详述了CAD/CAM这一产业革命中扮演着主力的新技,从CAD/CAM的各项功CAD/CAM运用于机械制造中通过一定的方法提高刀具制造精度。笔者介绍了CAD/CAM在刀具设计、加工、及其后续改进中的使用和设计理念,论述了CAD/CAM技术在提高刀具制造方面的巨大价值。另外,本文也在阐述CAD/CAM的在阐述了CAD/CAM技术运用的各个功能后,对该技术在未来的发展前景做了展望,指出在CAD/CAM强有力的辅助技术的支撑下,我国的机械设计与制造将会迎来下一个新世纪。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the