精益管理、六西格玛、约束理论等工业工程方法的系统化集成应用

简要回顾了精益管理、六西格玛、约束理论等工业工程方法的基本概念和原理,分析了这些方法的局限性;阐述了工业工程方法集成的必要性;基于不同方法的组合、整合以及融合贯通三个层面提出了多种方法集成的方法和模式;介绍了工业工程方法的集成在企业中的实际应用案例。     

精益与6σ的比较研究

对精益制造和6σ这两种卓越的业务改进方法进行了比较研究.从各方法本身的演化发展及性质上作了比较,得出二者的共性及各方法的独特性,再从各方法的特点、组织文化和过程方法角度进行了比较,分析各自的优势和不足之处,揭示了两种方法本质的一致性和过程方法的互补性,为两种方法的完美结合提供了基础支撑.     

机械产品模块化集成设计方法研究

分析总结了现有的模块化设计方法,并对其进行了分类分析,将其归纳为侧重功能的模块化设计方法和基于结构的模块化设计方法两类,并总结了其不足之处.在此基础上,提出了一种集成式的模块化设计方法,以流程图的形式描述了该集成式方法的内容和步骤,阐述了该方法的特点.     

降低多载波通信峰均比的方法探讨

分析了多载波通信系统中高峰均比问题的来源、峰均比的特性以及大峰均比对系统性能的影响,介绍了选择性映射方法、部分传输序列方法、数字信号裁剪方法等几种比较有效和实用的降低峰均比的方法,描述了这些方法的原理、实现方法和优缺点,比较了这些方法的性能和实现代价,在这些方法的基础上提出了低峰均比多载波通信系统的一般性实现方案.     

纤维铺放轨迹规划的两种方法及其比较研究

为了实现纤维铺放轨迹规划,本文提出了两种方法,即网格化方法和CAD软件的二次开发方法。针对网格化方法,提出了自由曲面的网格化方法和四边形网格铺放轨迹生成算法。针对CAD软件的二次开发方法,基于UG软件,提出了可变计算步长的初始轨迹计算方法、轨迹优化算法和丝束数量计算方法。以某型号的S形飞机进气道为参考模型,利用两种方法分别进行了轨迹规划。最后,对两种开发方法进行了比较研究,发现第二种方法相对于第一种方法具有功能强、开发周期短、与CAD软件的集成度高等优点,得出了其更适合铺放软件开发的结论。     

标准化方法和方法标准化

本文分别深入讨论了标准化方法和方法标准化的内涵,剖析了它们的理性形成关系和应用关系,研究了它们在标准化范畴拥有的关系和地位,深入讨论了统一化、互换性、通用化、系列化、模块化等标准化形式形成标准化方法的理论关系,理论上证明了一些标准化形式的标准化属性,详细讨论了方法标准化的方法对象的分类关系、实践关系和范畴,深入研究了标准化方法和方法标准化的相互依赖和对立统一的哲理关系。     

量子化学方法在化学计算方面的应用

概括地介绍了3种基本的量子化学计算方法:从头算法,密度泛函方法,半经验算法;简要介绍了近年来新发展起来的组合方法、线性比例方法、遗传算法等计算方法;综述了各种量子化学计算方法在各个领域的应用;展望了量子化学计算的发展方向及其发展趋势.     

航空装备研制项目标准化效益评估方法研究

本文深入研究了航空装备研制项目标准化效益评估方法的构建方法,系统介绍了评估方法的步骤,并以某型飞机的真实数据验证了评估方法的准确度。     

GB/T228-2002实施要点(续)

标准中保留了旧标准中的四种方法，删去了逐级施力的人工方法。四种方法都是图解方法(包括自动方法)。     

结构振动试验中测点优化布置研究

本文对结构振动试验中的测点布置方法进行了研究,提出了基于数值试验的最佳测点优化布置方法,用本文方法布置测点与用经验方法有很大的不同,这种方法的拟合误差较小。本文中给出了一个应用实例,说明了这种方法的应用价值。     

提高测量RCS的扫频方法精度研究

为提高测量RCS值的扫频方法的精度,从环境要求入手,提出了改进环境的基本措施,给出了一些解决的办法;最后通过测试技术手段消除了隔离误差.从结果可以得出测量的精度达到要求.     

Validation of the Simpson-finite-difference time domain method for evaluating the electromagnetic field in the vicinity of the lightning channel initiated at ground level

The authors propose a hybrid method, which is a combination between the Simpson method and finitedifference time domain (FDTD) method for evaluating the electromagnetic field radiated by lightning. The proposed method is an alternative approach that takes advantage of this combination to calculate, first, the radiated magnetic field with the Simpson method, and, second based partially on the FDTD method, the electric field. The suitability of this approach is checked through different examples.     

A Method of Reproducing the Triple Point of Mercury in the Working Standards of the Unit of Temperature

A method of replacing the triple point of mercury by the melting point of gallium when reproducing the ITS-90 International Temperature Scale is considered. A method of estimating the systematic error and of determining the conditions under which the method can be used is proposed.     

Application of the finite element method to the design of permanent magnets

A new method of determining the lengths of magnets in a magnetic circuit by using the finite element method has been developed. This method has the advantage that the lengths of magnets which produce the prescribed flux distribution can be directly calculated. In this paper, the error of this method is discussed at first, and then an example of application determining the shape of a magnet is shown. This method is effective for the design of magnetic circuits consisting of several permanent magnets and the determination of the shapes of magnets.     

硬泡沫塑料的力学性能分析:压缩弹性模量分析与计算机摸拟

对包装行业中常用的一类包装材料—硬泡沫塑料的压缩弹性模量的估算方法进行了探讨，发展了以力学模型为基础的随机模拟方法。以PUR发泡硬泡沫塑料为例，将此方法的计算结果与试验数据进行了比较。本方法既反映泡沫塑料的结构的力学性质，又体现了结构参数的随机特征，并且算法简单，编程容易，耗机时小，利于工程应用。     

Solution of the poisson equation: Comparison of the Galerkin and control-volume methods

The two-dimensional Poisson equation is solved by the finite element method which uses rectangular elements and the bilinear shape function. Two kinds of weighting functions are employed, which correspond to the Galerkin method and the control-volume method. The results for three test problems, for which exact analytical solutions are available, show that the control-volume method leads to errors that are about one-half of the errors given by the Galerkin method. Incidentally, the five-point finite difference method is found to give errors which are nearly equal to those for the Galerkin method.     

Characterization of flaws using the zeroes of the real and imaginary parts of the ultrasonic scattering amplitude

A new method for determining the size of flaws, such as cracks and voids, in structural materials is reported. The method is based on the observation that, for a wide class of flaws, the zeroes in the real and imaginary parts of the scattering amplitude occur at characteristic frequencies which depend on the flaw size. The method of reconstruction using the zeroes is simpler than the inverse Born approximation because the flaw sizes are extracted directly from the characteristic frequencies. The new method employs the same data input as the inverse Born algorithm and has certain common limitations. Following a theoretical treatment, experimental results are presented for a number of different types of flaws.     

确定毛细管尺寸的当量方法研究

在类比法和当量法基础上，提出多根毛细管之间长度、内径相互转换的当量方法。指出毛细管的摩擦系数对当量转换公式有直接的影响。计算表明，当N／Neq=1．5时，采用不同毛细管摩擦阻力系数进行毛细管当量长度的计算结果差别在6％以内。以制热量为8．5kW和9．85kW的空调机组采用的毛细管为基准，通过类比方法和笔者提出的当量方法计算制热量18kW的空调机组应采用的毛细管的几何尺寸。实验表明：以8．5kW机组为基准时，毛细管内径和长度的计算值和实验值分别相差-7．2％和2．9％；以9．85kW机组为基准时，毛细管内径和长度的计算值和实验值分别相差-6．5％和12．7％。实验说明笔者提出的方法可以用来指导空调机组的毛细管匹配实验。     

Modification of the LSMPS method for the conservation of the thermal energy in laser irradiation processes

In this work, new least-square moving particle semi-implicit (LSMPS) formulations for the modeling of the heat conduction in laser irradiation processes for both thick blocks and thin plates are developed. These new LSMPS formulations guarantee the conservation of the total thermal energy during the heat exchange between particles. The conservation of the thermal energy in the LSMPS method was implemented together with multiresolution techniques for the discretization of the domain with particles of different sizes so that a better characterization of the thermal gradients in the vicinity of the laser beam can be obtained. The simulation of laser irradiation processes for thin plates is still very challenging for particle methods with spherical particles and this is essentially because it is difficult to accommodate a minimum number of particles along the thickness direction without increasing considerably the resolution or the number of particles in the entire plate. In order to overcome this difficulty, a new multiresolution method based on particles with ellipsoidal shapes was also developed for a more efficient modeling of the laser irradiation in thin plates. By conducting the heat conduction simulations, in which the standard LSMPS method can provide accurate temperature distribution and by comparing the results with an analytical solution, it was confirmed that the proposed method is as accurate as the standard LSMPS method. Moreover, the heat conduction with an external heat source, in which the total thermal energy is not conserved by using the standard LSMPS method, was successfully simulated by using the proposed method. The simulations of laser irradiations were also conducted, and the validity of the proposed method has been confirmed by comparing numerical results with experimental data.     

Application of the pseudospectral time-domain method to the scattering of light by nonspherical particles

The pseudospectral time-domain (PSTD) method is a powerful approach for computing the single-scattering properties of arbitrarily shaped particles with small-to-moderate-sized parameters. In the PSTD method, the spatial derivative approximation based on the spectral method is more accurate than its counterpart based on the finite-difference technique. Additionally, the PSTD method can substantially diminish accumulated errors that increase with the spatial scale and temporal duration of simulation. We report on the application of the PSTD method to the scattering of light by nonspherical ice particles. The applicability of the PSTD method is validated against the Lorenz-Mie theory and the T-matrix method. The phase functions computed from the PSTD method and the Lorenz-Mie theory agree well for size parameters as large as 80. Furthermore, the PSTD code is also applied to the scattering of light by nonspherical ice crystals, namely, hollow hexagonal columns and aggregates, which are frequently observed in cirrus clouds. The phase functions computed from the PSTD method are compared with the counterparts computed from the finite-difference time-domain (FDTD) method for a size parameter of 20 and an incident wavelength of 3.7 microm. The comparisons show good agreement between the two methods.