基于美国钢结构设计规范的主次梁铰接连接设计

通过详细阐述美国AISC钢结构设计规范的LRFD设计方法(99版)对钢结构主次梁采用单连接板的螺栓铰接连接计算要求,并以实际项目举例论述,以期相关人员对该节点的计算有更多的理解,弥补现行国标和设计手册对此类节点论述的不足,并为相关工程计算提供参考。     

高速大功率柴油机活塞销材料及加工工艺优化

分析了材料及加工工艺对活塞销显微组织和疲劳性能的影响,通过改善材料纯净度、减轻带状组织、优化渗碳淬火工艺得到良好的渗层组织,使活塞销的强度、耐磨性和尺寸稳定性得到较大提高,疲劳寿命超过10 000 h。     

A method for representation of component geometry using discrete pin for reconfigurable moulds

Moulding plays a paramount role in our daily life. Traditional moulding is often dedicated and expensive. As the current market trend moves from mass production towards small batch and large variation production, the demand for a mould that can reconfigure itself for different components is greater than ever. The reconfiguration of mould is often realized through discrete pins. Previous research in that field had focused on the hardware of pin actuation in order to move pins up or down to represent different components and lock the pins at certain positions. Little research has been conducted into support software development that enables rapid reconfiguration of discrete pins to represent component geometry.This paper addresses a new method of software development for the reconfigurable mould utilising discrete pins. The overall aim of the method is to provide an interface for generic discrete pin tooling in order to enable quick reconfiguration of the mould to represent component geometry. The software is composed of three parts: part discretization, pin matrix construction and adjustment and pin matrix verification.     

高精度销孔加工的互换性保证

在机械制造中,遵循互换性原则,不仅能显著提高劳动生产率,而且能有效保证产品质量和降低成本。因此,互换性是机械加工制造中的重要生产原则与有效技术措施。介绍了ZYW系列钻机定位销孔较高的位置度要求及保证相关形位精度所采取的加工方法和检测措施。     

卷筒纸印刷机折页戳针凸轮的分析与优化设计

印刷工业趋于高速化的今天，行业竞争加剧，印刷成本逐步上升，以致业者的利润不同程度下降。因此，提高印刷速度、提高单位劳动生产率已成为印刷业必选的途径之一。通过对折页机戳针凸轮进行优化设计，并作出优化后的凸轮曲线，以适应折页机转速的提高。通过分析、改进、试车试验后表明，改进后的戳针凸轮能够满足折页机高速的需求。     

Pro/E族表在模具标准件设计中的应用

本文以导柱为例,介绍了怎样利用Pro/E族表进行模具标准件设计。     

Physicochemical properties of hull-less barley fibre-rich fractions varying in particle size and their potential as functional ingredients in two-layer flat bread

The performance of barley fibre-rich fractions (FRF), as high dietary fibre ingredients, in two-layer flat bread was investigated. In addition, the effects of particle size reduction by pin milling on functional properties of FRF were studied. FRF enriched in non-starch polysaccharides (β-glucans and arabinoxylans) were obtained by roller milling of hull-less barley. Pin milling (PM) of FRF significantly reduced their particle size, slightly increased the solubility of β-glucans and arabinoxylans, and increased the viscosity of water slurries containing FRF. The addition of 20% of barley FRF to wheat flour significantly increased dough water absorption and weakened the dough properties, as indicated by farinograph mixing curves, but the FRF-enriched doughs exhibited good handling characteristics at the dividing and sheeting stages. The appearance, diameter, layer separation, crumb, and aroma of the FRF-enriched flat breads were comparable to that of the control. The PM of FRF did not significantly affect the dough handling or the quality characteristics of flat breads. The addition of 20% of barley FRF to wheat flour flat bread provided substantial health benefits by significantly increasing the total and soluble dietary fibre contents and by decreasing starch digestibility.     

一个很有价值的新型钢结构节点

在开发利用地铁上空空间的活动中创造了中心受压穿心铰支座,又通过各种结构设计的综合研究,揭示了中心受压穿心铰支座更深层的优点和价值。梁、桁架类的受弯构件,应用中心受压穿心铰支座和柱子连接,就会产生没有弯矩传给柱子的效果,而且对柱子产生了三百六十度的约束,因此对大跨度、超大跨度、高层、超高层的开拓提供了一个行之有效的新思路。不仅如此,笔者在给工程公司展开咨询活动中,发现这种新型的钢结构节点对施工技术的开拓,建立自主知识产权等有很大的创新推动力,笔者诚恳地介绍给大家,希望大家有更多的创造。     

Design of “silent” circular saws

Abstract

This paper addresses a new problem of aligning two rows of movable terminals in order to minimize the channel width and via usage in the channel. The alignment problem of movable terminals is subject to the constraint that the number of vertical tracks used is not increased in the process. This constraint is not considerated in the paper referred to [6] which first considered the alignment problem of movable terminals. This problem is first shown to be NP‐complete, therefore, we present a heuristic algorithm. All examples presented in [2] including Deutsch's difficult example are used as the test routing problems. The programs were coded in C and implemented on SUN 3/110 workstation.     

The 68000 and its interface

The 68000 represents the new generation of mature microprocessors. It is mature because it is powerful both in terms of its facilities and its computational throughput, and yet it is neither difficult to program nor to design systems around. This paper provides a simple introduction to the way in which a 68000 is interfaced to the other components of a microcomputer system. As the 68000 has so many facilities, only the basic details of its interfacing capabilities are provided.