基于DEA的加工单元绩效改进

加工单元是制造企业的最小生产单位,其绩效评价涉及许多指标,包括质量指标、时间指标和财务指标等.如何将不同指标进行综合评价是企业生产管理者所关注的问题.现对DEA的不同模型进行了研究,并进一步通过C2R的效率排序模型对水平比较和连续改进方法进行了探讨.通过一个实际的对20个加工单元进行相对绩效分析的案例,讨论了加工单元绩效评价和改进的具体运用方法.     

Initial design domain reset method for genetic algorithm with parallel processing

The Genetic Algorithm (GA), an optimization technique based on the theory of natural selection, has proven to be a relatively robust means of searching for global optimum. It converges to the global optimum point without auxiliary information such as differentiation of function. In the case of a complex problem, the GA involves a large population number and requires a lot of computing time. To improve the process, this research used parallel processing with several personal computers. Parallel process technique is classified into two methods according to subpopulation’s size and number. One is the fine-grained method (FGM), and the other is the coarse-grained method (CGM). This study selected the CGM as a parallel process technique because the load is equally divided among several computers. The given design domain should be reduced according to the degree of feasibility, because mechanical system problems have constraints. The reduced domain is used as an initial design domain. It is consistent with the feasible domain and the infeasible domain around feasible domain boundary. This parallel process used the Message Passing Interface library.     

圆刻机智能控制系统

应用计算机技术,对圆计量光栅刻划过程的自动控制进行研究,介绍了微机控制细分刻划的原理和该智能控制系统的结构。并且叙述了多种任意等分光栅盘的刻划方法。     

非对称锥齿轮加工

当锥齿轮本身不对称 ,存在较大的不平衡质量时 ,锥齿轮加工过程中会出现较大振动 ,加工精度及粗糙度不能满足要求。以焦作矿山机器股份有限公司某锥齿轮配件为例 ,提供一种加工非对称锥齿轮的方法     

Central crack in a piezoelectric disc

This study is concerned with the general solution of the field intensity factors and energy release rate for a Griffith crack in a piezoelectric ceramic of finite radius under combined anti-plane mechanical and in-plane electrical loading. Both electrically continuous and impermeable crack surface conditions are considered. Employing Mellin transforms and Fourier series, the problem is reduced to dual integral forms. The solution to the resulting expressions is expressed in terms of Fredholm integral equation of the second kind. The solutions are provided to study the influence of the crack length, the crack surface boundary conditions on the intensity factors and the energy release rate.     

SiC长纤维增强Ti基复合材料的制备

Si C长纤维增强 Ti基复合材料在航空领域有广阔的应用前景 ,本文对其制备方法进行了评述。比较了箔 -纤维法、浆料带铸造法、等离子喷涂法及纤维涂层法制备 Ti基复合材料的优缺点及制备成本 ,认为采用纤维涂层法制备 Ti基复合材料航空发动机零部件较好。本文还用纤维涂层法制备了 SCS- 6 Si C/Ti- 10 2 3复合材料试样     

涡街流量计信号处理的软件方法

采用软件方法计算其输出信号的频率是项新技术。本文用高级语言实现不同的谱分析算法，对仿真信号进行处理，比较其特点，以克服实验中的局限和困难，为实际装置的研制提供科学依据。     

Quantitative theory of ideal phase-contrast microscopy,taking object width into account

In ‘ideal’ phase-contrast microscopy all the direct light and none of the diffracted light is influenced by the phase plate in the back focal plane of the objective. Contrary to almost all previous work, it appears that the intensity of an ideal phase-contrast image is affected not only by the transmittance and retardation of the object and of the phase plate, but also by the width of the specimen (or total width of multiple specimens) relative to the microscopic field. Equations and computer code are presented with which the intensity of such images can be calculated. Previously published equations are special cases, and implicitly or explictly assume either that the object is of negligible width, or occupies precisely half the microscopic field. The absolute brightness of an image in ideal central dark-field microscopy is a function of the object retardation, but the intensity of the image relative to the background is a function only of the width of the object(s) relative to the field. The equations give results for ideal phase-contrast microscopy identical with those of a computer program simulating microscopic imaging. The program can in addition take into account non-ideal factors including a finite width of phase plate, finite objective aperture, deviations from best focus, glare, primary spherical aberration and obliquity of the coherent illumination.     

Effect of acid-treatment and colloidal-processing conditions on the room temperature mechanical and electrical properties of 3YTZP/MWNT ceramic nanocomposites

Different colloidal powder processing routines have been used to prepare composites of 3 mol% Y₂O₃ -ZrO₂ (tetragonal zirconia polycrystals, 3YTZP) with 2.5 vol% multiwall carbon nanotubes (MWNT) with the aim of achieving a homogeneous distribution of the MWNTs in the ceramic, eliminating agglomerates but also minimizing carbon nanotube (CNT) damage during processing. Modifications of the acid treatment applied to the nanotubes, including subjecting them to stirring or ultrasonic agitation, and use of acid or basic pH during composite powder mixing have been approached.No MWNT damage during processing was detected by Raman spectroscopy. CNT bundles were found in all the composites forming different patterns depending on the processing route. Similar values of hardness were obtained for all the composites, while different anisotropy in fracture propagation was found when studying parallel and perpendicular directions to the sintering pressing axis on the cross sections of the composites due to the MWNT preferential alignment. The CNT bundles were found to act as fracture short paths. A similar anisotropic behavior was observed for the electrical conductivity. These results have been correlated to the different microstructures obtained in the composites prepared with different processing routines.     

几种智能表错接线查找与处理

智能表在整个电力系统十分重要,因此加大对智能表的分析研究,包括智能表出现错接线的排查和处理方法.这些如果处理得当就能够使电力系统为人们提供的服务更加可靠.