产品停产后服务备件供应链的决策分析与协调契约研究

以产品停产后服务备件供应中断问题为背景,研究了由产品制造商、备件供应商和后市场制造服务商构成的服务备件供应链决策问题和基于回购契约的协调机制。首先针对产品制造商采取末次订购和后市场应急采购策略的情形,构建Stackelberg博弈模型并分析均衡下各企业的最优决策,发现制造商在同时选择末次订购和应急采购时的期望利润低于仅选择末次订购的情形,因而不具有主动选择应急采购的意愿。随后探究了该供应链系统的协调问题,发现回购契约能实现供应链协调,且各企业利润均为回购价格的线性单调函数。通过数值试验进一步展示了实现各成员企业利润帕累托改进的契约组合,并分析了其受成本参数变化的影响。     

基于作业成本法的医疗物资TCO优化模型

针对传统医疗物资采购主要关注采购价格、忽视医疗物资供应链成本这一问题,提出了一种结合作业成本法(ABC)与总体拥有成本(TCO)理论的医疗物资TCO优化模型。首先,运用ABC详细分析并核算医疗物资供应链成本,如供应商维持成本、质量检验成本、运输成本及手术延期成本等;然后,通过建立医疗物资TCO优化模型优化医疗物资采购策略。最后,通过分析天津市某三级甲等医院医疗物资采购案例,证明本模型可以有效地降低医疗物资采购成本,并为医院成本控制管理提供合理建议。     

价格柔性契约下需求依赖价格的供应链策略研究

利用Stackelberg博弈模型研究价格柔性契约下零售商和供应商的策略。由于产品市场价格的波动,零售商和供应商签订价格柔性契约来应对市场价格波动带来的利润风险,零售商面临的市场需求依赖于其销售价格,供应商决定价格柔性契约的参数。首先,零售商根据价格对需求的影响大小和签订的价格柔性契约参数决定产品的零售价格,然后供应商根据零售商的零售价格决定柔性契约的价格风险分担系数。考虑了加和型和乘积型价格影响需求两种情况,计算得出价格柔性契约下零售商的最优定价以及供应商的最优价格风险分担系数。研究结果可以为价格柔性契约下需求依赖价格的供应链成员决策提供理论和方法指导。     

考虑供应链中断风险的最优供应商数量决策北大核心CSSCI

针对存在供应链中断风险的供应商数量选择问题,分析了由交易成本、风险损失、采购成本构成的采购总成本与供应商数量的关系。首先考虑到供应商的供应风险和市场的需求风险,引入数量弹性契约,对供应链中断风险进行了考察。然后在此基础上,构建了以采购总成本最小化为目标的考虑供应链中断风险的最优供应商数量决策模型。最后,通过算例分析验证了该模型的可行性,并探讨了机会主义成本、合作程度、市场需求均值、弹性系数、供应风险概率等相关参数对最优供应商数量的影响。     

考虑供应链中断风险的最优供应商数量决策

针对存在供应链中断风险的供应商数量选择问题,分析了由交易成本、风险损失、采购成本构成的采购总成本与供应商数量的关系。首先考虑到供应商的供应风险和市场的需求风险,引入数量弹性契约,对供应链中断风险进行了考察。然后在此基础上,构建了以采购总成本最小化为目标的考虑供应链中断风险的最优供应商数量决策模型。最后,通过算例分析验证了该模型的可行性,并探讨了机会主义成本、合作程度、市场需求均值、弹性系数、供应风险概率等相关参数对最优供应商数量的影响。     

考虑需求紧迫度差异与公平分配的三级应急物资调度研究

各受灾点因灾情不同对获取不同类别物资的需求紧迫度存在较大差异,忽略这一现实情况的模型会导致有限应急物资无法公平分配和高成本等问题。与已有文献相比,首先,引入了CRITIC法计量各灾点对有限物资需求的波动性与冲突性,提出需求紧迫度量化方法;其次,运用极小极大函数对已有研究的公平目标予以改进;然后,针对突发灾害时长途调运物资的现实情况,采用“储备点-中转站-受灾点”三级结构进行分析;之后,建立了以各灾点最大物资短缺度最小和调度成本最小为目标的多目标混合整数规划模型;最后,利用模糊理论对模型进行等价转化,设计改进遗传算法进行求解。算例分析证明,该模型在保障多受灾点之间物资分配公平性的同时,能够有效控制调度成本,可为现实突发灾害应急物资调度提供决策支持。     

回购契约下应对突发事件的供应链协调策略

在基本回购契约模型基础上,分析了回购契约下实现供应链协调的条件,并针对突发事件造成零售商面临的需求分布变化时供应链协调被打破的问题,提出了具有抗突发事件性的回购契约。这个契约主要将增加的供应商成本考虑进回购价格,使得供应商新增加的成本能够在供应商和零售商之间分配,从而使新的回购契约实现对突发事件的协调应对。应用一个算例对比加以说明。     

物资招标采购中组合预测的线性规划方法

结合企业在物资招标采购中大批量订货时,对物资采购量的供应商合理分配及采购费用问题,利用灰色预测法、自适应滤波法及线性回归预测法进行组合预测确定物资采购量,运用层次分析法确定供应商相应权重的基础上建立线性规划模型,力图达到采购的合理分配和采购费用最低的目的.因此,对于解决企业大批量物资采购招标中供应商的合理分配及供应量的确定,以达到企业采购成本最小化的问题,提出了一种有效的方法.     

基于持续抽检的电力物资多阶段动态采购模型及系统

针对电力物资集中采购模式中由于采购批量大、合同周期长而导致的不稳定供应问题,提出一种多阶段迭代修正式的电力物资动态采购模型,运用持续质量抽检进行供应商动态调整。首先根据经济订购批量模型确定最佳招标批次、划分标包,并设定多阶段招标模式及供应商评价指标体系;同时依托供应商绩效评价系统,获取历史抽检数据并迭代预测各供应商物资质量,通过建立标包份额动态分配模型动态修正供应商供应量。通过具体案例对模型进行了示例和验证,并对产品质量与供货量的关联性进行了敏感性分析,为采购方有效控制物资质量、供应商提高中标率提供了指导。最后,介绍了项目组开发的一个基于移动物联网的电力物资送检系统,为本文所提的评价模型提供了可行的实施环境。     

两个供应商和单个零售商组成的供应链成本信息共享和协调契约研究

研究两个供应商和单个零售商构成的供应链的成本信息共享策略和协调契约,两个供应商的商品为可替代的同质商品且成本不同,零售商关于两种产品的市场需求与两者的零售价格线性相关。首先利用Stackerberg博弈和Betrand博弈模型计算了完全信息下的各方分散决策;其次探讨了信息不对称条件下两个供应商的利润变化及两个供应商之间的产品成本信息分享策略;最后将完全信息下的供应链分散决策和集中决策进行对比,证明了双重边际效应的存在,并提出了协调该供应链的价格折扣契约。研究结果可以为成本信息不对称条件下两个供应商和单个零售商组成的供应链的成本信息分享策略和协调契约签订提供理论和方法指导,具有重要的理论和现实意义。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.