双载具式多层穿梭车立体仓库货位优化研究

目的为提高双载具式多层穿梭车立体仓库的运作效率,对其货位优化进行研究。方法针对双载具式多层穿梭车立体仓库货位优化作业系统的特点,考虑其运动过程中的加(减)速度特性,建立以入库时间最短为目标的货位分配优化模型。通过设计结合交叉变异算子的混合植物繁殖算法对该模型进行优化求解,从而确定最佳货位分配方案,缩短货位分配时间。结果实例分析表明,混合植物繁殖算法与遗传算法和物繁殖算法相比,收敛速度更快、优化效率更高。结论混合植物繁殖算法能够有效地缩短双载具式多层穿梭车立体仓库的货位分配时间,提高了仓库运作效率。     

基于二进制粒群的拣选作业优化

目的提高电子标签拣选系统中拣选作业的效率与货位占有率。方法以某电子拣选库为研究对象,提出以订单完成度、货位占有率以及货位聚集度为目标的拣选优化模型。设计基于二进制粒子群算法(BPSO)和遗传算法(GA)的模型求解仿生算法。结果试验及优化结果表明,基于BPSO的电子拣选库订单的完成度、货位占有率以及货位聚集度较遗传算法更高。结论基于二进制粒子群算法求解的优化模型较符合实际的电子拣选库人工拣选作业,同时仓储作业货位的利用率及拣选效率得到了提高。     

缓冲区容量约束下发动机混流装配线排序研究

为解决缓冲区容量约束下发动机混流装配排序问题,以关键部件消耗均匀化和最大完工时间最小化为目标,建立了优化数学模型,设计了一种多目标遗传算法,采用了混合交叉算子和启发式变异方法,并设计了基于帕累托分级和共享函数的适应度函数,将多目标遗传算法和多目标模拟退火算法的优化结果进行了比较。研究结果表明,多目标遗传算法在满意度和计算效率方面均优于多目标模拟退火算法,是一种有效的混流装配线排序问题求解算法。     

基于改进模拟退火遗传算法的自动化立体仓库 货位优化

针对自动化立体仓库出入库作业量大、品类复杂等特点,对仓库货位展开优化研究,遵循周转率原则、货架稳定原则、关联原则等,构建了提高出库效率、提高货架稳定性、增强货物相关性的货位优化模型。使用传统模拟退火算法、遗传算法与改进模拟退火遗传算法求解模型,得出货位优化结果。对比分析结果证明了在解决货位优化问题时,改进算法比传统基础算法更加有效,能更好地改善自动化立体仓库空间使用率低、拣选效率低、货位摆放混乱的现状。     

基于“货到人”拣选系统的动态货位分配研究

目的 为了提高“货到人”拣选系统的订单拣选效率，研究了电商仓库货位初始存储状态为非空情况下的商品货位分配问题。方法 考虑货架上现存商品信息、仓库空余货位数、待补货商品和新收入商品信息，提出基于商品关联度的分散存储策略，以极大化货架上所有存储商品的关联度之和为目标构建商品上架与下架的动态货位分配数学模型，并设计贪婪算法，再采用改进粒子群算法对贪婪算法得到的结果进行优化。结果 基于商品关联度的分散存储策略可以减少货架平均搬运次数29.32%左右。结论 与随机分配策略相比，文中提出的货位分配策略能够有效提升整个电商仓储中心的拣选速度。     

基于遗传算法的线束加工仓库货位优化研究

目的文中以减少汽车线束加工立体仓库堆垛机运行时间和距离,提高订单处理效率为目的,建立货位优化的数学模型。方法根据某汽车线束加工立体仓库的真实情况,在分析历史订单数据的基础上,通过基于定位储存策略的改进遗传算法对货位分配问题进行仿真和求解。结果仿真结果表明,定位存储策略优于就近存储策略、随机存储策略和分类存储策略,其减少堆垛机运行时间的比例分别达到了18.8%,16.9%和35.7%。结论采用定位存储模型能有效改善汽车线束加工立体仓库系统处理生产订单的效率。     

最小偏差法在机械多目标优化设计中的应用

提出了处理多目标问题的最小偏差法,并将其应用于机械多目标优化设计。以流体动压滑动轴承多目标优化设计为例,建立了以摩擦系数最小、发热量最小和承载能力最大为目标函数的多目标优化设计数学模型,根据最小偏差法原理构造统一目标函数,利用改进遗传算法对该问题进行了优化设计。算例整个求解过程和结果表明,该方法既可以避免人为因素的影响,又能够获得比常规设计更佳的设计参数,同时也验证了所提方法对于解决机械多目标优化设计问题的有效性和可行性。     

遗传算法在轮胎结构多目标优化设计中的应用

在轮胎结构设计中应用一种基于共享小生境技术的遗传算法(简称Pareto GA),用来求解多目标优化问题的Pareto最优解集合。在综合考虑轮胎带束层的耐久性和轮胎重量的基础上,通过三维有限元分析和室内耐久性试验建立了优化轮胎带束层的数学模型,采用Pareto遗传算法对该数学模型进行求解,获得了分散性很好的Pareto最优解集合。为了检验优化的效果,应用三维有限元分析技术,对优化胎与原胎进行了分析与对比。结果表明,该优化过程达到了预期的目的。     

产品操作界面元素布局多目标优化设计

目的针对产品设计中操作界面布局设计时存在的随意性、不确定性大等问题,使用多目标优化设计的方法,寻找界面元素的最优布置,以提升界面的使用舒适性和人机交互效率。方法在分析了工效学准则和界面布局美度评价准则的基础上,确立了层次性、相关性、简洁性和舒适性四个界面布局基本原则,并依据原则构建了界面元素布局多目标优化数学模型,在此模型的基础上采用改进的遗传算法,建立基于遗传算法的界面元素布局多目标优化方法。结果给出产品操作界面布局设计的基本原则,提出一种基于遗传算法的产品操作界面元素布局的多目标优化方法及流程。结论提出的布局原则和优化方法能较好地协助设计师获得满足设计需求的布局方案,实例结果表明了理论模型的合理性与遗传算法对于界面元素布局多目标优化问题求解的有效性。     

基于遗传算法的订单拣货实时排序问题研究

根据配送中心订单拣货问题的特点,以订单客户的满意度为目标,建立了数学模型,并设计了相应的遗传算法来求解该问题。在算例中,将遗传算法与先到先服务和最早工期优先规则进行了比较,结果表明,遗传算法可以明显优化目标函数值,有助于提高配送中心的拣货效率,提高客户满意度,具有良好的实用性。     

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.