Ti-ZrO2系梯度材料的制备与显微结构研究

采用粉末冶金法热压合成了Ｔｉ－ＺｒＯ２系梯度功能材料,用有限元法模拟了设计材料的残余热应力分布。利用扫描电镜、电子探针,透射电镜和Ｘ射线衍射等手段,对Ｔｉ－ＺｒＯ２系梯度材料组成相的分布形态、相组成以及组元之间的界面结构状态等进行了详细的研究,结果表明：合成的材料具有宏观组织不均匀性与微观组织连续性的特征,Ｔｉ－ＺｒＯ２系梯度材料由α－Ｔｉ四方相ＺｒＯ２和单斜相ＺｒＯ２组成,合成条件下组元Ｔｉ和Ｚ     

渤中25—1油田单点系泊至浮式生产储油船混输软管工艺研究

根据BZ19-4油田开发要求,对BZ25-1油田已经运行的单点系泊到浮式生产储;由船混输软管展开校核研究。通过分析现场运行数据,从中得到规律性认识,以期指导实践。     

TiB2对Ni基合金激光熔覆层组织与性能的影响

采用5 kW CO2激光器在低碳钢表面熔覆Ni基合金层及TiB2/Ni基合金金属陶瓷涂层,研究了两种涂层的组织、显微硬度以及滑动磨损特性.结果表明,Ni基合金层主要组成相为γ-(Ni,Fe),Cr23C6等,TiB2/Ni基合金复合涂层组成相主要有γ-(Ni,Fe),Ni3B,TiB2和TiC等;Ni基合金层由发达γ-(Ni,Fe)枝晶和其间共晶组织所组成,TiB2/Ni基合金复合涂层典型组织为等轴固溶体以及其间细小共晶组织;TiB2对熔覆层的组织有显著的影响,使熔覆层组织细化,并由树枝晶转变为等轴晶;加入TiB2可显著提高Ni基合金涂层的显微硬度及耐磨性能.     

激光熔覆镍基金属陶瓷涂层组织与高温磨损性能的研究

通过显微组织观察及高温干摩擦磨损试验，对激光熔覆镍基金属陶瓷涂层及其高温干摩擦磨损性能进行了研究。结果表明，Ni21＋20％WC＋0．5％CeO2熔覆层组织细小，高温干摩擦磨损性能最好。     

三维图像多相分割的变分水平集方法

变分水平集方法是图像分割等领域出现的新的建模方法,借助多个水平集函数可有效地实现图像多相分割.但在区域/相的通用表达、不同区域内图像模型的表达、通用的能量函的设计、高维图像分割中的拓展研究等方面仍是图像处理的变分方法、水平集方法、偏微分方程方法等研究的热点问题.文中以三维图像为研究对象,系统地建立了一种新的三维图像多相分割的变分水平集方法.该方法用n-1个水平集函数划分n个区域,并基于Heaviside函数设汁出区域划分的通用的特征函数;其能量泛函包括通用的区域模型、边缘检测模型和水平集函数为符号距离函数的约束项3部分;最后,针对所得到的曲面演化方程,采用半隐式差分格式进行离散,并对多种类型三维图像进行分割验证了所提出模型的通用性和有效性.     

New Dental Alloys with Special Consumer Properties

The purpose of the investigation was to create a new gold alloy of yellow for casting the frames of metal ceramic dentures. The yellow color corresponds to the consumer and aesthetic needs of some patients, because it is a sign of the metal, which is noble and innocuous. The main alloying elements of the majority of gold alloys for metal-ceramics are platinum and palladium, which increase the strength characteristics. Copper, tin, and other precious metals and base metals are also introduced in these alloys. At the same time, it is necessary to ensure the correspondence of the properties of the alloy with those of the ceramics applied onto the metal frame. For this purpose, the thermal expansion coefficient of the alloy (TEC) should be in a range of 13.5~14.5 ×10 6 K 1 when heated from 20 to 600 ℃ . The two-component alloys, alloying of gold with platinum and palladium results in a decrease in the TEC, and the introduction of copper, silver, and tin, increases it. Multidirectional influence of the alloying elements is a factor in achieving compliance of the TEC with the given values of the alloy. In multicomponent systems, however, the mutual influence of individual components on the properties of the alloy is unpredictable. This also applies to the color characteristics of the alloys, which vary in the direction of reducing the yellowness with increasing concentration of platinum and palladium, while other elements may have the opposite effect on the results. Yellowness index (YI), calculated according to the results of spectrophotometric studies, has been chosen as an objective indicator of color. In this study, the requirement for YI was given not less than 25; the color of such alloys can be called light yellow. All the alloys investigated contained 85% (by weight) of gold. Therefore, higher corrosion resistance and biological inertness of a finished dental products were ensured. Among the alloys that met the yellowness/TEC requirements, two alloys have been selected that were "most yellow" (PLAGODENT-PLUS and PLAGODENT-BIO). Their adhesive properties met the requirements of GOST R 51736-2001 to alloys for metal ceramics.     

适合通信系统的低压、大电流电源的现状及展望

本文主要介绍通信系统中低电压大电流电源设计所面临的稳压、散热、输入噪声和成本等方面的问题，分析多相技术、板上电源、同步整流和次级控制等新技术，并给出了一种低电压、大电流电源的设计文例。     

自蔓延高温合成金属陶瓷复合材料工艺研究

本文首先阐述了自蔓延高温合成技术的发展和应用现状。其次,采用SHS技术在T10钢材表面合成了厚为10 mm的A12O3/Fe表面梯度复合层,分析出复合材料的成分呈梯度变化,金属陶瓷由陶瓷层逐步过渡到基体金属。同时,本文还研究了各添加剂元素对金属陶瓷结合等性能的影响规律。     

CFD分析在汽车加油过程中的应用研究

应用流体模拟仿真软件STAR CCM+建立加油管加油过程的三维仿真模型,运用三维瞬态湍流中的多相流VOF模型模拟燃油在加油管内的流动,判断是否出现燃油回流而导致"提前跳枪"的风险,最后再通过试验验证该仿真模型。结果表明:仿真结果与试验结果吻合,说明运用流体仿真技术对燃油系统加油管的设计具有指导性意义,同时还可以较大缩短开发周期与减少设计成本。     

自蔓延高温合成工艺研究

阐述了自蔓延高温合成技术的发展和应用现状,并且利用SHS技术在普碳钢材表面合成了厚为10mm的Al_2O_3/Fe表面梯度复合层,通过理化手段测试出复合材料的成分呈梯度变化,金属陶瓷连接陶瓷层与基体钢表面,陶瓷与普碳钢具有良好的连接强度,不易剥离。同时还探索了各添加剂元素对金属陶瓷结合等性能的影响规律。