采用MOD工艺制备PZT压电薄膜及其性能的研究

文中比较详细地研究了采用金属有机化合物热分解（ＭＯＤ）法制备锆钛酸铅Ｐｂ（Ｚｒ０．５２Ｔｉ０．４８）Ｏ３铁电薄膜的工艺及ＰＺＴ薄膜的介电性能。利用ＸＲＤ分析了薄膜的结晶过程,制得具有钙钛矿结构的ＰＺＴ薄膜铁电极有利于钙钛矿相形成,薄膜的介电温谱研究结果表明：薄膜有居里温度约为４３０℃（１ｋＨｚ）。     

用VC++对SolidWorks二次开发实现标准件建模

介绍了以VC++6.0为开发平台,利用Microsoft Access建立数据库,使用ODBC开放式数据库接口访问数据库,对SolidWorks进行二次开发的方法。通过API函数实现标准件的三维建模,并进行了实例验证。     

GPS全球定位系统设计

以GSU-38AO GPS接收模块为核心,介绍了系统的硬件电路及软件流程图,所设计的全球定位系统具有全球定位、自动控制、实时性好等多方面优点,具有较好的应用发展前景.     

Radial nanofretting behaviors of ultrathin carbon nitride film on silicon substrate

With a nanoindenter, the radial nanofretting behaviors of amorphous ultrathin carbon nitride (a-CN_x) film on the silicon substrate were investigated by a spherical diamond indenter. The experimental results indicate that the radial nanofretting damage on a-CN_x film usually successively experiences the buckling, cracking and detachment of film. These damages can be easily detected by the variation in the apparent contact stiffness. Generally, the initial increase in the contact stiffness indicates the buckling of film; the following sharp decrease in the contact stiffness reveals the initiation and propagation of circular cracks in film; the final stable contact stiffness implies the detachment of film.     

Artificial lubrication of joint prostheses

The great success of total joint replacement in surgery has been disturbed mainly by the later loosening of the prostheses and wear of the plastic components. In an attempt to improve long term performance, and to eliminate the adverse effects of wear debris, the concept of artificial lubrication and encapsulation of the joint articulating parts has been proposed by a number of workers in recent years^1–3. This paper covers the selection of a lubricant candidate and a tribological study on both all-metal and metal/plastic combinations.     

(Ba1-ySry)6-3xSm8+2xTi18O54微波介质陶瓷的结构及性能

研究了（Ba1-ySry）6-3xSm8＋2xTi18O54（x=2／3，0．0≤y≤0．5）微波介质陶瓷的晶体结构和性能。结果表明：用锶取代钡形成了钨青铜结构的固溶体相，随着锶取代量的增加，晶格常数线性降低；同时，介电常数增大，在y=0．5时获得最大值（80．95）；介电损耗在y=0．3达到了最低值（0．00016）。频率温度系数随着锶取代量的增加由负变正。     

结合模糊(C+P)均值聚类和SP-V-支持向量机的TSK分类器

为获得具有模糊规则自适应约简性能和较好的泛化性能的TSK分类器,本文提出了一种结合模糊(C+P)均值聚类(FCPM)算法和SP-V-支持向量机(SVM)分类算法来构建TSK(Takagi-Sugeno-Kang)分类器的方法。该方法首先用FCPM聚类算法对训练数据进行聚类;然后根据聚类结果确定TSK分类器的模糊规则前件中的高斯隶属度函数的中心和宽度参数;最后采用成组稀疏约束SP-V-SVM算法对模糊规则后件参数进行学习,该算法不仅改善了系统的泛化性能,还使系统具有模糊规则自适应约简功能,使得系统更为紧凑。与相关算法在UCI和IDA标准数据集分类实验中的模糊规则数和分类性能对比表明:用提出的分类算法所构造的TSK分类器不仅具有较好的分类性能,而且模糊规则数少,有利于构建更为紧凑的模糊分类系统。     

Transverse roughness in short journal bearing under dynamic loading

The stochastic theory developed by Christensen is applied to the analysis of dynamically loaded short rough bearings which have striations transverse to the direction of motion. An approximate polynomial is used, in place of a Gaussian function, to represent the roughness profile. To make the analysis applicable to real lubrication situations, it is assumed that the standard deviation of the roughness height and the minimum film thickness are of the same order. Attention is focussed on the cyclic squeeze films under sinusoidal loading. It is concluded that the transverse roughness results in an increase in the side leakage. The effect of roughness is more pronounced when the load direction is reversed.     

IDEF0 Model of the Measurement Planning for a Workpiece Machined by a Machining Centre

A comprehensive analysis of the entire measuring operation for a workpiece machined by a machining centre should be conducted systematically before the application of a planning technique. For this purpose, an IDEF0 model is used in this paper to plan the measuring sequence and operation of a coordinate measuring system for a workpiece machined by a machining centre. Generally speaking, a machining centre can machine workpieces having complicated shapes. Therefore, the planning of measurement procedures and operations on a workpiece machined by a machine centre requires consideration of issues such as the position and measuring sequence of the measurement points, how to avoid probe collision during measuring, which fixture elements are required for measuring fixtures, and where the support points of fixtures and position of fixture locations should be.     

加速器质谱(AMS)测量中~(41)Ca标准样品的制备

简要介绍加速器质谱 ( MAS)测量样品采用 Ca H2 以排除 4 1K的干扰。其制备主要包括两步 :首先是Ca O与过量的 Zr粉混合 ,在高温下还原出金属钙 ,然后金属钙与氢气在密闭容器中加热反应生成 Ca H2 。从金属钙到 Ca H2 的转换效率大于 90 %。     

变形温度对耐候钢高温塑性的影响

在不同的变形温度(600~1250℃)下,以3×10-3s-1的应变速率对试样进行拉伸直至断裂。绘制出高温塑性曲线,分析变形温度对耐候钢高温塑性的影响。耐候钢的第Ⅲ脆性区出现在700~850℃,脆性区间温度范围较窄;900~1150℃为最佳塑性区间。     

The dissociation of (a+c) misfit dislocations at the InGaN/GaN interface

In hexagonal materials, ( a+c ) dislocations are typically observed to dissociate into partial dislocations. Edge ( a+c ) dislocations are introduced into (0001) nitride semiconductor layers by the process of plastic relaxation. As there is an increasing interest in obtaining relaxed InGaN buffer layers for the deposition of high In content structures, the study of the dissociation mechanism of misfit ( a+c ) dislocations laying at the InGaN/GaN interface is then crucial for understanding their nucleation and glide mechanisms. In the case of the presented plastically relaxed InGaN layers deposited on GaN substrates, we observe a trigonal network of ( a+c ) dislocations extending at the interface with a rotation of 3° from <1 $\overline{1}$00> directions. High-resolution microscopy studies show that these dislocations are dissociated into two Frank–Shockley 1/6<2 $\overline{2}$03> partial dislocations with the I₁ BSF spreading between them. Atomistic simulations of a dissociated edge ( a+c ) dislocation revealed a 3/5-atom ring structure for the cores of both partial dislocations. The observed separation between two partial dislocations must result from the climb of at least one of the dislocations during the dissociation process, possibly induced by the mismatch stress in the InGaN layer.     

未来变速箱面临的挑战

现代传动系统必需满足足的燃油经济性，较少的有害气体排放和日益增大的舒适性要求，本文提出了可有助于达到这些目的方法，它可实现最佳的高效的自动变速箱和最佳的传动系操纵。