基于模糊分析的环形起重机偏轨箱形主梁的优化设计

这里就环形起重机偏轨箱形主梁的设计问题,根据模糊分析的基本理论提出一种模糊优化设计方法。即在普通优化设计基础上考虑设计取值的不确定性以及影响设计的某些因素如应力性质、材质好坏又很难用确定的数值表示的情况,建立了模糊约束条件。在满足使用要求的前提下,以偏轨箱形主梁的总质量最小的优化目标,建立了该问题的模糊优化设计数学模型,并介绍了优化方法和效果。     

皮带轮旋压机床用嵌入式开放性数控系统的研究

为了增强机床的柔性,缩短安装和调试的时间,使系统能随时根据用户的要求更新设备的软、硬件,将嵌入式开放性数控系统应用于四工位皮带轮旋压机床,并根据旋压机床的特点对嵌入式开放性数控系统的硬件和软件架构进行了重点分析和研究,结果表明:以PC机为核心的NC嵌入PC型硬件架构使得数控系统有较好的开放性、集成性和可靠性,而上下层型软件架构可以对实时性任务和非实时性任务等多个任务进行并行处理,极大地增加了CPU利用率.最后给出了该数控系统的二轴联动插补和位置控制执行程序.     

带滚珠丝杠齿轮自动脱螺纹机构的压铸模

铸件螺纹脱模是压铸模设计的难点之一.自动旋转脱螺纹一般采用齿轮-齿条机构或液压-齿轮机构.本压铸模则采用一种新机构--滚珠丝杠-齿轮脱螺纹机构.该机构利用压铸机推杆为螺纹型环旋转脱模提供动力,通过滚珠丝杠-齿轮机构将压铸机推杆的直线运动,转变为螺纹型环旋转运动,实现螺纹铸件自动脱模.     

Investigation of the ultimate particle size distribution of a carbonate sand

A series of ring shear tests were conducted to investigate the ultimate particle size distribution of a carbonate sand. The tests were carried out under different stress levels, on three types of specimens: 1) uniformly graded specimens made of dry natural sand 2) remoulded specimens of the crushed sand after first shearing to large strains 3) specimens made of natural sand grains but with the same grading as in (2). The first series of tests on type (1), carried out to very large strains, led to apparently stable gradings, distinct for each stress level. Only limited additional particle breakage could be induced by remoulding the specimens after shearing (type (2)) and subjecting them to more shearing. Tests on specimens created at the apparently stable gradings (type (3)) but from the intact sand particles however led to significantly greater breakage. For the three types a stable, fractal grading was achieved. Analyses of the soil particles’ shape showed that the aspect ratio, sphericity and circularity reach a steady value at large strains, in parallel to reaching a stable grading. The mobilized angle of shearing resistance however was not significantly different in the different types of samples, suggesting the final grading dominates the behaviour.     

Potentiality of Indian pineapple leaf fiber for apparels

The use of textile-grade fiber extracted from the Indian pineapple leaf is an unexplored area. Pineapple leaf fiber (PALF) is fine, soft, and moderately strong and is much acceptable for fashion garment. An attempt has been made to extract and soften Indian PALF from the pineapple leaves by decortication and subsequent water retting. Decorticated cum retted fiber has shown better physicomechanical and surface appearance properties than decorticated fiber. Fine yarn (38 tex) was spun in a suitable spinning system, and the property performance was found to be suitable to make eco-sustainable novelty fabric. Fabric was developed by using cotton as warp yarn and PALF-based yarn as weft in a handloom. The developed fabric shows very good physical and mechanical properties, desired for apparels. This inferred that Indian PALF may be successfully used to make eco-niche apparel quality fabric as well as novelty textiles.     

集聚纺车间地沟均匀吸风设计方法探讨

探讨集聚纺车间地沟均匀吸风设计方法。介绍了地沟均匀吸风的设计原理和实现均匀吸风的措施;分析了变风量系统对均匀吸风性能的影响;介绍了变风量均匀吸风系统的设计;计算分析表明:回风沟道应采用变截面分段设计法,吸风口采用条缝型形高速自适应风口,吸风口面积之和与沟道截面积之比不大于0.4,前后吸口的吸风不均匀程度可以控制在15%以内。认为:采用支沟道变截面分段设计能较好地控制吸风的均匀性,可以保证集聚纺车间气流均匀稳定。     

一种可固化防漏工作液水化机理研究

研究了一种低密度（1.30 g/cm3）可固化防漏工作液,用于解决低压易漏失井段在固井时,因地层承压能力低、易漏失、窜槽,导致固井质量不高的问题。通过在优质的隔离液中加入一种具有固化性能的材料（2.60~2.90 g/cm3）替代常规的加重剂,配制一种低密度可固化工作液。该工作液能有效平衡地层压力并在环空中固化,从而对易漏地层起到防漏效果、提高固井质量。重点分析了该体系的固化后试样强度及水化机理,研究发现:工作液固化强度发展的实质是OH-对固化剂玻璃体结构的破坏;通过对配方的调节能实现从30~90℃固化试样都具备一定的抗压强度。该体系的研发对于防漏工作液的设计提供了一种新的思路,同时还可以运用于钻井工程中堵漏,提高地层的承压能力。      

脆性材料有效爆破范围的试验研究

针对无底柱分段崩落法爆破中出现的问题,采用脆性材料对井下矿扇形炮孔爆破进行相似材料的模拟试验,试验揭示了扇形爆破的方向性与顺势破坏效应,可以指导矿山爆破优化设计,提高爆破能利用率,降低矿石贫化率。     

OTN电交叉技术及组网应用分析

光传送网（OTN）技术正逐步取代SDH／MSTP、WDM技术,成为光传送网主流技术。本文在对OTN电交叉技术和设备以及国内运营商网络业务需求特点进行深入分析的基础上,提出了采用OTN电交叉技术组建环形网和网状网的建设方案。     

半导体环形腔激光器输出特性理论与实验

首先导出了光纤环形腔半导体激光器中光子数密度的解析表达式后,分别从理论和实验上研究了阈值电流、输出功率和光纤耦合比之间的依赖关系。结果表明,阈值电流与光纤耦合比的对数满足线性关系;同时,在特定的偏置电流下,存在一个最佳的光纤耦合比使输出功率为最大。这将对于环形腔半导体激光器的理论研究和优化器件结构有所裨益。