统计能量分析参数的综合确定方法及应用

根据统计能量分析(SEA)法，对某卫星声振环境和某返回舱噪声环境进行了计算分析。提出了仅通过一次试验获取SEA参数的综合确定方法，根据这种方法对SEA模型参数进行修正，利用修正过的参数计算的卫星结构响应结果与试验结果更加接近。另外，还针对SEA模型参数的灵敏度问题进行了分析。在返回舱的应用中，将SEA法预示结果与曲线拟合方法预示结果及试验结果相比较，结果说明三者一致。     

机械系统的振动同步,控制同步与复合同步

近十多年来,在机械工业的各个部门,振动同步与控制同步得到了广泛的应用,本文介绍该领域在近期内的发展和主要研究成果,即双机及多机系统的振动同步,双机机械系统的控制同步,定速比控制传动,复合同步,多机系统的控制同步及多个液压油缸的控制同步等,并给出计算机仿真的若干成果。     

Scheduling with agreements: new results

In this paper, the problem of scheduling with agreements (SWA) is considered. In scheduling, this consists of a set of jobs non-preemptively on identical machines subject to constraints that only some specific jobs can be scheduled concurrently on different machines. These constraints are given by an agreement graph and the aim is to minimise the makespan. In the case of two machines we extend two NP-hardness results of SWA with processing times at most three that hold for bipartite agreement graphs to more general agreement graphs. Complexity results of SWA are established in the case of split and complement of bipartite graphs. We also present some approximation results for SWA.     

二阶混合非线性椭圆方程的强迫振动性质

本文对含有阻尼项二阶混合非线性椭圆方程,建立了其所有解振动的判定定理,这些定理包含和改进了其对应的常微分方程和超线性椭圆方程相应的结果.     

A study on thermo mechanical fatigue life prediction of Ni-base superalloy

Gas turbine blades are exposed to high-temperature degradation environments due to flames and mechanical loads as a results of high-speed rotation during operation. In addition, blades are exposed to thermo-mechanical fatigue due to frequent start and shutdown. Therefore, it is necessary to evaluate the lifetime of blade materials.In this study, the TMF life of a Ni-base superalloy applied to gas turbine blade was predicted based on LCF and TMF test results. The LCF tests were conducted under various strain ranges based on gas turbine operating conditions. In addition, IP (in-phase) and OP (out of-phase) TMF tests were conducted under various strain ranges.Finally, a fatigue life prediction model was drawn from the LCF and TMF test results. The correlation between the LCF and TMF test results was also evaluated with respect to fatigue life.     

基于随机权重粒子群和K-均值聚类的图像分割

K-均值聚类具有简单、快速的特点,因此被广泛应用于图像分割领域.但K-均值聚类容易陷入局部最优,影响图像分割效果.针对K-均值的缺点,提出一种基于随机权重粒子群优化（RWPSO）和K-均值聚类的图像分割算法RWPSOK.在算法运行初期,利用随机权重粒子群优化的全局搜索能力,避免算法陷入局部最优;在算法运行后期,利用K-均值聚类的局部搜索能力,实现算法快速收敛.实验表明：RWPSOK算法能有效地克服K-均值聚类易陷入局部最优的缺点,图像分割效果得到了明显改善;与传统粒子群与K-均值聚类混合算法（PSOK）相比,RWPSOK算法具有更好的分割效果和更高的分割效率.     

The role of carbon nanofibers on thermo-mechanical properties of polymer matrix composites and their effect on reduction of residual stresses

In this research, the effects of carbon nanofibers (CNFs) on thermo-elastic properties of carbon fiber (CF)/epoxy composite for the reduction of thermal residual stresses (TRS) using micromechanical relations were studied. In the first step, micromechanical models to calculate the coefficient of thermal expansion (CTE) and Young's modulus of CNF/epoxy and CNF/CF/epoxy nanocomposites were developed and compared with experimental results of the other researchers. The obtained results of the CTE and Young's modulus of modified Schapery and Halpin-Tsai theories have good agreement with the experimental results. In the second step, the classical lamination theory (CLT) was employed to determine the TRS for CNF/CF/epoxy laminated nanocomposites. Also, the theoretical results of the CLT were compared with experimental results. Finally, reduction of the TRS using the CLT for different lay-ups such as cross ply, angle ply, and quasi-isotropic laminates were obtained. The results demonstrated that the addition of 1% weight fraction of CNF can reduce the TRS that the most reduction occurred in the unsymmetric cross-ply laminate by up to 27%.     

Hybridizing the harmony search algorithm with a spreadsheet ‘Solver’ for solving continuous engineering optimization problems

In this article, a hybrid global–local optimization algorithm is proposed to solve continuous engineering optimization problems. In the proposed algorithm, the harmony search (HS) algorithm is used as a global-search method and hybridized with a spreadsheet ‘Solver’ to improve the results of the HS algorithm. With this purpose, the hybrid HS–Solver algorithm has been proposed. In order to test the performance of the proposed hybrid HS–Solver algorithm, several unconstrained, constrained, and structural-engineering optimization problems have been solved and their results are compared with other deterministic and stochastic solution methods. Also, an empirical study has been carried out to test the performance of the proposed hybrid HS–Solver algorithm for different sets of HS solution parameters. Identified results showed that the hybrid HS–Solver algorithm requires fewer iterations and gives more effective results than other deterministic and stochastic solution algorithms.     

混凝土试块比对实验室结果的统计分析

能力验证是保证检验检测机构持续满足资质认定的基本条件和要求,能力验证的结果,需进行结果评价。不同类型的实验室能力验证方案,采取的评价计算模式各有不同。在实际工作中,通常采用以求稳健Z比分数,来评定结果的满意程度。而在实验室采用Z比分数来统计结果,显得十分重要。     

Limit analysis of FGM circular plates subjected to arbitrary rotational symmetric loads using von-Mises yield criterion

In this paper, employing the limit analysis theorem, critical loading on functionally graded (FG) circular plate with simply supported boundary conditions and subjected to an arbitrary rotationally symmetric loading is determined. The material behavior follows a rigid-perfectly plastic model and yielding obeys the von-Mises criterion. In the homogeneous case, the highly nonlinear ordinary differential equation governing the problem is analytically solved using a variational iteration method. In other cases, numerical results are reported. Finally, the results are compared with those of the FG plate with Tresca yield criterion and also in the homogeneous case with those of employing the von-Mises yield criterion. A good correspondence is observed between the calculated results and those available in the literature.     

几类偶数阶非线性微分方程的区间振动性

本文给出了几类偶数阶非线性微分方程和时滞微分方程的一些新的区间振动准则,所得结果推广了一些已知文献中的结论.     

A numerical study of hypoelastic and hyperelastic large strain viscoplastic Perzyna type models

For the case of metals with large viscoplastic strains, it is necessary to define appropriate constitutive models in order to obtain reliable results from the simulations. In this paper, two large strain viscoplastic Perzyna type models are considered. The first constitutive model has been proposed by Ponthot, and the elastic response is based on hypoelasticity. In this case, the kinematics of the constitutive model is based on the additive decomposition of the rate deformation tensor. The second constitutive model has been proposed by García Garino et al., and the elasticresponse is based on hyperelasticity. In this case, the kinematics of the constitutive model is based on the multiplicativedecomposition of the deformation gradient tensor. In both cases, the resultant numerical models have been implemented in updated Lagrangian formulation. In this work, global and local numerical results of the mechanical response of both constitutive models are analyzed and discussed. To this end, numerical experiments are performed and different parameters of the constitutive models are tested in order to study the sensitivity of the resultantalgorithms. In particular, the evolution of the reaction forces, the effective plastic strain, the deformed shapes and the sensitivity of the numerical results to the finite element mesh discretization have been compared and analyzed. The obtained results show that both models have a very good agreement and represent very well the characteristic of the viscoplastic constitutive model.     

最小二乘法在热电偶热电势校准中的应用

在热电偶的实际应用过程中，分度点往往需要根据校准点用高阶多项式进行拟合求得。本文首先确定最优的多项式拟合阶次，同时鉴于目前国际上对校准结果表示的规范化要求，每一个校准结果都有一个不确定度与之相对应，本文对最优的多项式拟合结果的不确定度进行了评定。     

An Aggregate Production Planning Model Incorporating Dynamic Productivity: Part II. Solution Methodology and Analysis

In Part I in a previous issue, the authors developed a procedure for incorporating dynamic productivity considerations into aggregate planning models. However, the dynamic cost functions of these models result in heterogeneous decision systems which are difficult to solve. In this article a solution methodology is discussed that was developed for dynamic aggregate planning models. In addition, the results from using a dynamic productivity aggregate planning model are analyzed. It is concluded that dynamic productivity can be significant; incorporating these considerations into a model can provide more realistic results.     

KM6空间环模设备液氮系统中液体喷射器的试验研究

本文对ＫＭ６空间环境模拟设备液氮系统中液体喷射器进行了试验研究。其中稳压性能试验结果与理论分析相符；在补液性能试验中．试验结果也与计算结果基本相符，表明了所设计的液体喷射器已达到设计要求．     

任意载荷激励下梁单元的局部效应修正

本文推导了在任意荷载激励下梁单元局部效应的修正公式,在不同荷载激励下对结构进行动力响应分析,计算结果表明,考虑局部效应可以使动内力计算结果更为精确。在进行大型复杂结构的动力响应分析时,通过考虑局部效应,可在计算模型大大简化的同时,获得较为精确的计算结果。     

数字摄影机动态范围的主客观评价关系探究

为了了解数字影像质量与人眼主观视觉感受之间的关系,本文以摄影机动态范围为例,进行一系列测试实验,初步探索影像质量技术参数在动态范围这一角度与人眼主观感受之间的关系.测试实验选择了三台常见的不同厂商的摄影机型,拍摄动态范围的测试卡以及利用软件进行读取数据来获取客观测试结果,同时拍摄不同光线下的实景让观察者进行观看来获取主...     

The influence of the electronic current on the measurement of ion polarization in evaporated silicon oxide

In this paper the influence of the electronic leakage current on the measurement of the ion polarization mechanism in thin film capacitors is investigated. A simple theory is given and is applied to small signal and large signal cases. The theoretical results are compared with the experimental data. In order to fit the theoretical analysis to the experimental results, a new hypothesis concerning ion enhancement is introduced.     

Lattice Dynamical Properties of Group-III Nitrides AN (A = B,Al, Ga and In) in Zinc-Blende Phase

In the present paper, we have calculated the phonon dispersion relations, phonon density of states, Debye characteristic temperature and the zone boundary phonons for group-III nitrides AN (A = B, Al, Ga and In) using eleven-parameter three-body shell model with both the ions being polarizable. Our calculated results are in good agreement with experimental results available in the literature.     

Technical note The stochastic flowshop makespan: some further results

In Middleton (1994a, b) various results were given for (finite) buffered and unbuffered stochastic flowshops. This short note amplifies and extends some of those results.