面向顾客化大量生产的物料需求算法的改进

分析了顾客化大量生产对MRPII的冲击,针对MRPII的核心部分物料清单BOM和生产计划生成机制对顾客化大量生产的不适应性,对已提出的模块化BOM(分层BOM)做了进一步改进,探讨了一种更灵活的物料需求算法.该算法基于改进的模块化BOM,综合了BOM中心算法,比传统物料需求计划具有更强的可靠性和实用性.最后给出了一个具体实例.     

客户化模式下面向产品的采购策略研究

分析了传统物料需求算法的不足和客户化模式下市场需求的特点,以采购BOM作为采购数据的组织形式和载体,采用语意数据模型化技术--IDEF方法,构建了采购BOM的生成过程模型,以实现采购数据与其他相关数据的集成管理.最后采取滚动计划的方法,并考虑安全库存和经济采购批量,给出了采购物料的生成算法模型,以实现库存的动态管理,提高采购的效益.     

基于启发式调度规则的能力需求计划算法

传统的能力需求计划方法不能准确地反映实际生产能力需求与负荷.为此设计了基于启发式调度规则的能力需求计划算法,该算法将基于启发式规则的调度算法作用于物料需求计划进行能力需求计算,并对设备负荷率、关键设备资源和关键任务等关键能力信息的计算方法进行了重新定义,以更加真实地反映计划期内计划的能力需求与设备负荷状态.该算法已应用...     

支持复杂装配线物料配送的BOM映射技术研究

在复杂装配线生产过程中,如何实现物料的按时有序配送和关键零部件的齐套控制是物料配送管理的主要难题.在分析产品装配结构、装配工艺流程以及物料配送规则的基础上,通过梳理“制造BOM—作业BOM—配送BOM”之间的转换映射关系,建立基于装配工艺流程的作业BOM生成方法和基于工位结构分解的配送BOM生成方法,实现对复杂装配生产线物料配送信息的一致性映射和完整性控制,为物料配送的精细化管理提供能够反映装配作业过程特征的数据描述模型.最后通过应用实例验证说明上述BOM转换映射技术的合理性和可行性.     

物料需求计划不稳定性的模拟研究

介绍物料需求计划不稳定性的基本概念和模拟研究方法。在不确定性需求的流动式计划环境下,研究冻结参数和计划算法在不同生产条件下对物料需求计划不稳定性的影响。通过设计模拟实验和大量模拟计算及统计分析表现：费用结构、预测模式、冻结比例、计划周期和计划算法对物料需求计划不稳定性有较大影响,且交互作用显著。研究结果对减小物料需求计划的不稳定性有一定指导意义。     

产品物料清单BOM的XML实现方法研究

针对产品物料清单(BOM)的复杂性、多样性、灵活性等特点,结合XML所具有的特点,提出了基于XML的BOM树的建立方法,由此有效地实现了数据的查询、修改和删除等操作.论文分析了产品全生命周期各阶段BOM数据的特点、演变过程;详细阐述了产品BOM结构的XML的建立优势;产品BOM树的XML模式的设计和实现;以及各种BOM视图之间的转化和BOM数据的交换.重点介绍了.Net Framework环境下BOM树的实现机制.     

基于分类和模块化的工程机械BOM构建

分析了工程机械BOM构建现状和不足,给出一种适合工程机械基于分类和模块化的超级BOM构建方案.从工程机械产品销售实际,对产品的主参数、特征参数、可选参数概念作出说明.将属于某特定型号工程机械产品的所有部件划分为公共部分、特征部分、可选部分,并建立相应部分虚拟层级.根据模块化思想,对特征部分和可选部分建立具有约束关系的选择模块.将物料分类原理应用于模块化超级BOM构建,运用Excel和VBA实现了产品编码自动生成和BOM自动构建功能.分析该方案特点并应用于工程机械产品BOM构建,结果表明,基于分类的模块化BOM构建方法简单易行、合理有效,能够快速准确构建单一产品BOM,对于工程机械信息化具有较好的参考价值.     

以计划网络为基础的MRP算法研究及实现

针对复杂产品制造企业应用常规MRP算法编制的生产计划存在有效性差、调整频繁、重复计算量大等问题,提出了一种以计划网络为基础的MRP算法.该算法是在常规MRP算法的基础上,将运算产生的多级需求计划指令与生产实际安排建立关联关系,应用网络计划技术构建零组件计划网络,增强和扩展了MRP功能,提高了需求计划指令的有效性,并在原型系统开发中得到可行性验证.     

基于供应链的大量定制生产计划原型系统

分析了大量定制模式下的BOM设计、订单处理模式和分层的生产计划,研究了基于供应链面向大量定制的生产计划原型系统MC—P及需求管理、生产计划与控制以及物流管理各子系统的功能设计与数据流程;最后总结了MC—P系统的特点。     

基于供应商产能约束的BOM研究

分析了现有BOM研究与应用中存在的问题.在传统BOM信息的基础上,考虑供应商产能因素,提出一种基于供应商产能约束的供应链型动态BOM模型和构造方法.该BOM模型能够动态适应供应链的变化.最后给出了动态BOM的实现流程,并通过案例予以说明.     

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.     

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.     

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.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.