用工业工程思想发现、解决和预防问题

在工厂现场问题研究的基础上,联系生活实际,对问题科学进行了研究.定义了什么叫问题;探讨了问题的本质;对工作生活中问题进行了分类;阐明了问题和风险以及问题和矛盾之间的关系.利用工业工程(IE)的思想,分析了普遍的如何发现问题及解决问题的思维过程;阐明了在工作和生活中如何利用问题的实质去发现问题,并最终解决和预防问题.报告了解决问题的三个原则、注意事项和步骤.     

n-m-k商人渡河问题解的存在性及算法实现

本文将商人渡河问题推广到最一般情况,即n-m-k商人渡河问题,建立了该问题的多步决策数学模型.首先,根据该数学模型得到一棵状态空间树,设计了采用递归和回溯方法遍历该状态空间树的算法步骤.其次,根据部分运行结果,分析了该问题的算法复杂度.最后,分析了该问题解的存在性,并给出了若干定理及其证明.本文已将商人渡河问题扩展成为广泛的经典例子,有利于解决实际生活中的问题.     

供应链中生产和运输协调调度问题初探

提出了解决供应链中生产和航空运输协调调度问题的理论框架.基于对生产调度和航空运输调度彼此制约关系的分析,协调调度问题被分解为两个子调度问题.建立了航空运输子调度问题的整数规划模型,并证明了该问题为NP完全问题.提出了基于倒排调度方法(backward scheduling method)的调度算法解单机生产调度子问题.     

生态旅游区固体废弃物回收的选址-路径问题

研究了生态旅游区废弃物逆向物流网络设计问题,包括中转站选址和车辆路径问题,并建立了最小化选址费用和运输费用的模型.选址路径问题为NP困难问题,采用了四叉树原理划分满足车辆容量限制的收集区,将问题化为小型的TSP问题.给出了算例验证模型和算法的有效性.     

具有边界摄动的反应扩散时滞方程奇摄动问题(英文)

本文研究了具有边界摄动的非线性时滞反应扩散方程奇摄动问题.首先得到了退化问题的解.其次构造了原问题的外部解.然后引入伸长变量构造了解的初始层校正项,得到了解的形式渐近展开式.最后在适当的假设下,利用微分不等式理论,证明了原初始边植问题解的渐近展开式的一致有效性.     

正确认识中国革命和建设中的农业、农村和农民问题

农业、农村和农民问题始终是中国革命和建设的根本问题.中国共产党人抓住农民问题这一中心,取得了中国革命的胜利.同样,紧紧抓住农业、农村和农民问题,从农村入手,中国共产党取得了社会主义革命和建设的胜利.对此,党的三代领导人都有深刻的认识,"三农"问题始终关系到党和国家的全局.     

装配线平衡系统研究与开发

装配线的平衡问题已有大量理论研究,但缺乏应用工具.为了消除该问题理论与实际应用之间的鸿沟,利用有效的算法,开发了一个装配线平衡的系统.简要介绍了装配线平衡问题及其求解算法,阐述了系统的功能及其实现过程.企业界的工程技术人员利用该系统可以有效地解决装配线平衡问题,从而提高装配线的生产效率.     

粘弹性流体的牛顿迭代两重网格方法(英文)

对于非线性粘弹性流体,本文提出了一种有限元两重网格方法.该方法需要首先在粗网格上求解非线性问题,然后在细网格上求解两个线性问题.这两个线性问题具有相同的刚度矩阵,只是右端项不同.我们进一步给出了该方法的误差估计.数值算例验证了理论结论,并且验证了方法的有效性.     

Brinkman-Forchheimer方程的加罚有限元方法

Brinkman-Forchheimer方程(BF方程)是具有强非线性项并满足无散度条件的流动控制方程,其中无散度条件的精确满足对控制方程的数值求解极其重要.为了放松无散度条件的限制,本文采用了加罚方法.为了得到加罚问题解的适定性,首先,利用加罚关系将压力项消去,证明了速度所满足的具有单调性的非线性椭圆变分问题等价于对应能量泛函的极小化问题,从而得到了速度的存在唯一性.进一步,利用LBB条件证明了BF方程加罚问题压力的存在唯一性.其次,证明了BF方程加罚问题的Galerkin变分问题的解关于加罚参数收敛到BF方程的Galerkin变分问题的解.最后,给出了BF方程加罚问题Galerkin变分问题的有限维逼近问题及其解的存在唯一性,并且得出了采用协调有限元离散的误差估计.数值算例表明加罚方法是有效的.     

粘弹性薄板动力响应问题的多重互易法

本文给出了粘弹性薄板动力响应问题的多重互易法（MRM）.首先在Laplace变换区域中得到了由重调和算子基本解序列给出的粘弹性板动力响应问题的MRM方法,再利用改进的Bellman反变换技术,求得原问题的解.讨论了MRM方法中的迭代误差估计.文末给出了数值算例,计算表明该方法具有较高精度和较快收敛性.适用于长时间的动力问题的计算.     

Pd-C高温共晶点复现装置研制

主要针对Pd-C高温共晶点复现装置的组成进行介绍,其中包括复现用高温均热炉炉体、温度控制系统、真空泵、充气保护装置、水冷系统、复现用的石墨坩埚、二等B型标准热电偶和Pt-Pd热电偶等。针对石墨坩埚的灌注和共晶点复现过程进行了描述,根据复现的试验数据进行了相应的分析。     

Similarity solutions for slender dry patches with thermocapillarity

The lubrication approximation is used to investigate slender dry patches in an infinitely wide film of viscous fluid flowing steadily on an inclined plane that is either heated or cooled relative to the surrounding atmosphere. Four non-isothermal situations in which thermocapillary effects play a significant role are considered.Similarity solutions describing a thermocapillary-driven flow with a dry patch that is widening or narrowing due to either gravitational or surface-tension effects on a non-uniformly heated or cooled substrate are obtained, and examples of these solutions, when the substrate temperature gradient depends on the longitudinal coordinate according to a general power law, are presented. When gravitational effects are strong, the solution contains a free parameter, and for each value of this parameter there is a unique solution representing both a narrowing pendent dry patch and a widening sessile dry patch, whose transverse profile has a monotonically increasing shape. When surface-tension effects are strong, the solution also contains a free parameter, and for each value of this parameter there is both a unique solution representing a narrowing dry patch, whose transverse profile has a monotonically increasing shape, and a one-parameter family of solutions representing a widening dry patch, whose transverse profile has a capillary ridge near the contact line and decays in an oscillatory manner far from it.Similarity solutions are also obtained for both a gravity-driven and a constant-surface-shear-stress-driven flow with a dry patch that is widening or narrowing due to thermocapillarity on a uniformly heated or cooled substrate. The solutions in both cases contain a free parameter, and for each value of this parameter there is a unique solution representing both a narrowing dry patch on a heated substrate and a widening dry patch on a cooled substrate, whose transverse profile has a monotonically increasing shape.     

The surface tension of HFC refrigerants and mixtures

The surface tension of the refrigerants R32, R125, R134a, R143a and R152a, as well as the binary refrigerant mixtures R32-R125, R32-R134a, R125-R134a, R125-R143a, R125- R152a, R143a-R134a and R134a-R152a, and the commercially available ternary mixtures R404A and R407C was measured across the temperature range from −50 to 60°C using a measuring unit based on the capillary rise method. Different formulations for calculation of the surface tension of the binary and ternary mixtures on the basis of the surface tension of the pure refrigerants were tested. With an approach based on mass proportions in the mixture, a good correspondence between the measured and calculated values was achieved.     

A Scheme for a Sustainable Urban Water Environmental System During the Urbanization Process in China

Urbanization is a potential factor in economic development, which is a main route to social development. As the scale of urbanization expands, the quality of the urban water environment may deteriorate, which can have a negative impact on sustainable urbanization. Therefore, a comprehensive understanding of the functions of the urban water environment is necessary, including its security, resources, ecology, landscape, culture, and economy. Furthermore, a deep analysis is required of the theoretical basis of the urban water environment, which is associated with geographical location, landscape ecology, and a low-carbon economy. In this paper, we expound the main principles for constructing a system for the urban water environment (including sustainable development, ecological priority, and regional differences), and suggest the content of an urban water environmental system. Such a system contains a natural water environment, an economic water environment, and a social water environment. The natural water environment is the base, an effective economic water environment is the focus, and a healthy social water environment is the essence of such a system. The construction of an urban water environment should rely on a comprehensive security system, complete scientific theory, and advanced technology.     

Effect of surface slip on Stokes flow past a spherical particle in infinite fluid and near a plane wall

The motion of a spherical particle in infinite linear flow and near a plane wall, subject to the slip boundary condition on both the particle surface and the wall, is studied in the limit of zero Reynolds number. In the case of infinite flow, an exact solution is derived using the singularity representation, and analytical expressions for the force, torque, and stresslet are derived in terms of slip coefficients generalizing the Stokes–Basset–Einstein law. The slip velocity reduces the drag force, torque, and the effective viscosity of a dilute suspension. In the case of wall-bounded flow, advantage is taken of the axial symmetry of the boundaries of the flow with respect to the axis that is normal to the wall and passes through the particle center to formulate the problem in terms of a system of one-dimensional integral equations for the first sine and cosine Fourier coefficients of the unknown traction and velocity along the boundary contour in a meridional plane. Numerical solutions furnish accurate predictions for (a) the force and torque exerted on a particle translating parallel to the wall in a quiescent fluid, (b) the force and torque exerted on a particle rotating about an axis that is parallel to the wall in a quiescent fluid, and (c) the translational and angular velocities of a freely suspended particle in simple shear flow parallel to the wall. For certain combinations of the wall and particle slip coefficients, a particle moving under the influence of a tangential force translates parallel to the wall without rotation, and a particle moving under the influence of a tangential torque rotates about an axis that is parallel to the wall without translation. For a particle convected in simple shear flow, minimum translational velocity is observed for no-slip surfaces. However, allowing for slip may either increase or decrease the particle angular velocity, and the dependence on the wall and particle slip coefficients is not necessarily monotonic.     

Granulation of ibuprofen/isonicotinamide co-crystals by continuous spray granulator (CTS-SGR)

The importance of granulation is paramount for tablet manufacturing, and is based on the fact that granulated powders are characterized by improved flowability, compressibility, segregation, and dust reduction. The aim of this study was to prepare and characterize continuous granules of high drug content by using a continuous-spray granulator (CTS-SGR). Ibuprofen (IBU), a drug of low-flowability, was selected as the model drug. As IBU has a low melting point and cannot easily granulate on its own, we employed isonicotinamide (INA) as a coformer that would allow us to prepare co-crystal granules containing 60 % IBU. The results of the undertaken differential scanning calorimetry and powder X-ray diffraction revealed that the IBU and the INA in the granules formed co-crystals. The granulation conditions affected the particle size and the yield of the granules; in fact, a low air supply temperature, a low atomizing air rate, and a high solution flow rate ensured a high granulation efficiency. Moreover, continuous granulation increased the yields of the formulations compared to those obtained through a short-run granulation, and high yields were obtained after applying a low atomizing air rate. The circularity of the granules exceeded 90 %, and their flowability improved when compared to that of the IBU bulk. The undertaking of dissolution studies revealed no change in the elution amount of IBU as a result of the co-crystallization. Our study shows that it is possible to produce high-content IBU granules in a direct and continuous manner through the co-crystallization of IBU and the use of a CTS-SGR.     

单源随机向量及其在随机分析中的应用

受正交展开思想的启发,定义了单源随机向量,证明了该文提出的单源随机向量的独立性,并就单源随机向量在随机分析中的应用进行了阐述,算例计算表明了这种单源分析方法的有效性。用单源随机向量表达复杂的随机系统,仅需1个基本随机变量,这对大幅减少随机分析的难度和计算量有重要意义,对基于相关理论的随机分析,如随机结构、随机场、随机过程以及复合随机问题,该方法都有应用价值。随机系统用单源随机向量模拟以后,相应的分析方法还有待进一步深入研究。     

Statistical Analysis of Macromolecular Chains in the Space Filled by Nanoparticles

The paper presents a combination of worm-like chain numerical models and one with a finite set of nano-particles. The primary objective of the models was to analyze the distribution of space in a system filled by particles. Information on the distribution of space was compared to properties of chains inside the set of particles. The set of nanoparticles was constructed with a tool generating a finite set of particles that is randomly distributed in a given space. The particles have a prescribed volume fraction and uniform size. First, the proportions of chains and particles were compared. The length of chain was expressed in terms of end-to-end length. It was then compared to the size of gaps between two particles. The volume of chain was compared to the volume of space delimited by the particles. Next, a set of 10,000 random chains was generated and these were introduced into the particle set. The contact of a chain with the surface of a particle resulted in the special structural elements of the chain: a chain connecting two different particles, a loop which begins and ends at the same particle, a part of a chain which is completely adhered to the particle surface, a chain attached to a particle with one free end, as well as completely free chains. The chains were classified under three classes: chains which were not in contact with particles, chains which were in contact with one particle, and chains which were in contact with two or more particles. A statistical representation of each class is presented. The contact between chain and particle can influence macroscopic properties such as those that are elastic.     

Rapid inversion of eddy current data for conductivity and thickness of metal coatings

A feature-based method that determines the thickness and electrical conductivity of a coating on a metal plate from the change in the frequency-dependent impedance of an eddy-current probe coil is presented. Recently a least-squares solution of this problem was presented, which, however, requires approximately 20 CPU minutes on a DEC 5000 work station for the analysis of each set of measurements. We show that a feature-based approach can reduce the time to a few seconds on the same processor. We start by showing that a three-parameter scaling of the resistive component of the impedance change vs. frequency leads to a simple and nearly universal curve. Consequently these parameters provide a simple and compact way of expressing the data. Next, we show that the three scaling parameters can be used to construct a look-up table that determines the conductivity and thickness of the coating. Finally, we test the method using experimental data.     

Multi-product continuous plant scheduling: combination of decomposition,genetic algorithm,and constructive heuristic

We propose a polylithic method for medium-term scheduling of a large-scale industrial plant operating in a continuous mode. The method combines a decomposition approach, a genetic algorithm (GA) and a constructive MILP-based heuristic. In the decomposition, decisions are made at two levels, using the rolling horizon approach. At the upper level, a reduced set of products and the time period is chosen to be considered in the lower level. At the lower level, a short-term scheduling MILP-model with event-based representation is used. A heuristic solution to the lower level problem is found using a constructive Moving Window heuristic guided by a genetic algorithm. The GA is applied for finding efficient utilisation of critical units in the lower level problem. For solving the one unit scheduling problem, a parallel dynamic programming algorithm is proposed. Implementation of the dynamic programming algorithm for a graphics processing unit (GPU) is incorporated in the GA for improving its performance. The experimental study of the proposed method on a real case of a large-scale plant shows a significant improvement of the solution quality and the solving time comparing to the pure decomposition algorithm proposed in the earlier study, and confirmed suitability of the proposed approach for the real-life production scheduling. In particular, the reduction of the number of changeovers and their duration in the obtained solution as well as the CPU time of solving the problem was about 60% using the new approach.