Geometric modeling of spatial constraints: objectives, methods and solid-modeling requirements

Robust Product Lifecycle Management (PLM) technology requires availability of informationally- complete models for all parts of a design-project including spatial constraints. This is the subject of the present investigation, leading to a new model for spatial constraints, the ``virtual solid', which generalizes a similar concept used by Sapidis and Theodosiou to model ``required free-spaces' in plants [14]. The present research focuses on the solid-modeling aspects of the virtual-solid methodology, and derives new solid-modeling problems (related to object definition and to object processing), whose robust treatment is a prerequisite for developing efficient models for complex spatial constraints.     

Rotational and helical surface approximation for reverse engineering

Given a surface in 3-space or scattered points from a surface, we investigate the problem of deciding whether the data may be fitted well by a cylindrical surface, a surface of revolution or a helical surface. Furthermore, we show how to compute an approximating surface and put special emphasis to basic shapes used in computer aided design. The algorithms apply methods of line geometry to the set of surface normals in combination with techniques of numerical approximation. The presented results possess applications in reverse engineering and computer aided manufacturing.     

Calculation of thermodynamic parameters of U–Pu–N system with carbon and oxygen impurities

Mixed nitride fuels are being considered for advanced FBR, but very little is known about the thermodynamic properties of these fuels. For an overall composition of the nitride fuel with small amounts of oxygen and carbon impurities, thermodynamic properties, e.g. carbon activity and partial pressures of nitrogen, carbon-monoxide, plutonium and uranium, were calculated in present work. These calculations were based on standard Gibbs free energies of the binary compounds, present in this multi-component system (U,Pu)–C–N–O. For an over all composition of the fuel, stable phase-field was determined by minimization of the Gibbs free energy of the system. The fabrication experiences of various workers, reported in literature, have shown that depending on the impurity content, nitride fuel can exist in two phase fields, mono-nitride phase in equilibrium with sesquinitride phase or mono-nitride phase in equilibrium with dioxide phase. Therefore, in present calculations special attention was given to the thermodynamic behavior of these two phase-fields. A comparison of calculated thermodynamic properties indicated that nitride fuel with dioxide as second phase will be superior to the one with sesquinitride.     

用单片机和EDA协同设计温度采集系统

本文介绍了一种用单片机和EDA协同设计温度采集系统,该温度采集系统能够实现PN结、热电阻(PT100)、热电偶(镍锘-镍硅K型)3种方式的温度测量。可以满足不同的测量范围、不同的测量精度及不同场合的需要。本设计采用EDA作为开发工具,搭配单片机控制,使得整个设计具有较新的设计思想。采用12ADC模数转换器,使得测量精度得到了极大地提高。数据处理采用现场可编程门阵列FPGA(EP1K30QC208-3),它极高的程序执行速度使得系统响应更快更精确。     

Development of TP310HCbN(07Cr25Ni21CbN) austenitic stainless steel tubes

Improving the unit heat efficiency,reducing coal consumption and the emission of CO₂ and meeting the requirements of environmental protection and energy conservation is the goal of the boiler and the power industry.Developments of large capacity and high parameter ultra-supercritical（USC） units are the tendency of the power industry.There is no doubt that the development of USC units is based on the development of materials, especially the materials used for super-heater and reheater in high-temperature USC boiler.Due to the long time exposure to the harsh environment,such as bearing the 600℃steam oxidation,and withstanding the corrosive flue gas and fly ash erosion,the materials require not only good high-temperature strength,but also a good corrosion resistance.In consideration of the requirements cited above,foreign countries had developed TP310HCbN （07Cr25Ni21CbN） austenitic heat-resistant steel.However,the domestic demands for this material still depend on import and the cost is high,so the boiler and the power industry expects eagerly that these steels can be produced by domestic metallurgical industry,especially Baosteel,to replace the imported products.In order to satisfy the requirements of domestic manufacturing super-heater and reheater used in ultra-supercritical power boiler,after developed T23、T91、T92、S30432 high pressure boiler tube,Baosteel began to develop TP310HCbN （07Cr25Ni21CbN）austenitic stainless steel tube in January of 2007.This study describes the composition design, the manufacturing process of product,and the assessment of performance of Baosteel’s TP310HCbN （07Cr25Ni21CbN）.The data indicates that properties of Baosteel’s TP310HCbN（07Cr25Ni21CbN） conform to the ASME SA-213 standard and GB5310 standard,so it can substitute the imported products and is suitable for manufacturing power station boiler of great capacity and high steam parameters.     

150 mm超厚水电站用钢07MnCrMoVR的组织性能

对150 mm超厚07MnCrMoVR水电钢的组织性能进行了研究,采用光学显微镜、扫描电子显微镜对试验钢的微观形貌进行了观察,采用拉伸试验机和低温冲击韧性试验机对试验钢力学性能进行了检验。结果表明:试验钢经第一次完全淬火和第二次两相区亚温临界淬火后近表面组织转变为板条马氏体和未熔铁素体相间出现,厚度1/4处和厚度1/2处组织转变为贝氏体+铁素体组织,高温回火后近表面转变为回火索氏体组织,厚度1/4处和厚度1/2处组织转变为回火贝氏体+铁素体+大量碳化物。     

热处理工艺对100 mm特厚07MnCrMoVR水电钢板组织性能的影响

对07MnCrMoR水电钢板的淬透性曲线进行了测定,利用淬火机和热处理炉对100 mm厚试验钢板进行了淬火和回火试验,并对试验钢进行了组织观察和力学性能测定。结果表明,随着试验钢距水冷端的距离增大,淬火组织由马氏体转变为粒状贝氏体,距离端部50 mm处转变为铁素体和粒状贝氏体的混合组织。试验钢板利用淬火机淬火后得到板条贝氏体+粒状贝氏体+先共析铁素体,回火后转变为铁素体+粒状贝氏体,同时大量的碳化物在铁素体基体和晶界处析出。试验钢最合理的热处理工艺为930℃30 min水冷淬火,660℃60 min空冷回火。     

昆明平流层-对流层雷达系统及初步探测结果

基于昆明站(25.6°N,103.8°E)ST雷达近一年的风场观测结果给出了5～22.1km高度范围内风场的季节变化特征及利用镜面反射方法和雷达回波功率数据估测了对流层顶的高度.结果显示:17 km是平均风特征发生变化的高度,即17 km以下夏季为西向风和南向风,其他季节为东向风和北向风,而17 km以上纬向风几乎全年盛行东向风,经向风变化则更为复杂,且二者与HWM07模式结果的变化特征不完全一致.估测得到的昆明上空对流层顶高度范围是14～17.6 km,由此推测对流层中强烈的对流活动很可能是形成平均风场该特征的主要原因.     

一株深海来源苏云金芽孢杆菌SWJS07所产蛋白酶的分离纯化及性质研究

利用超滤、硫酸铵盐析、DEAE Sepharose Fast Flow阴离子交换柱层析、Sephadex G-75分子筛柱层析对一株南海深海来源菌苏云金芽孢杆菌(B.thuringiensis)SWJS07所产蛋白酶进行分离纯化,纯化后经SDS-PAGE鉴定达到电泳纯,相对分子质量为37.0 k Da,酶的比活力提高了6.39倍,回收率为37.14%。研究其酶学性质表明,该蛋白酶最适催化温度为55℃,在30℃~45℃下稳定性较高,保温300 min残留酶活在80%以上;最适p H 6.5,在p H 6.0~9.0蛋白酶稳定,4℃放置24 h残留酶活在80%以上;2 m M Ca2+、Mn2+对蛋白酶有不同程度的激活作用,而Hg2+、Cd2+、Al3+则强烈地抑制蛋白酶活;当在蛋白酶中添加2 m M Ca2+、Mn2+时,其最适催化温度分别为60℃和55℃,蛋白酶活分别提高了32.86%和28.35%,60℃保温30 min相对酶活基本保持不变,与纯酶(相对酶活残留21.02%)相比蛋白酶的热稳定性显著提高;EDTA-Na2可强烈抑制蛋白酶活,推测该蛋白酶属于金属蛋白酶。     

J607RHDQ和LB-65L熔敷金属成分与性能对比

介绍了07Mn Ni Mo DR钢制乙烯球罐工程中所使用的国产焊条和日本进口焊条的建造实例,并对其化学成分、熔敷金属力学性能、扩散氢含量以及焊接试板的力学性能等数据进行分析,得出国产焊条与日本焊条的焊接接头力学性能指标相当,均可满足设计温度为-45~-50℃范围内07Mn Ni Mo DR钢制乙烯球罐的建造要求。