45＃-16 T型立式加工中心盘式刀库的设计

刀库是加工中心上最重要的部分之一,也是数控机床性能评价的关键之一。笔者对45＃-16 T型盘式刀库进行了传动设计、结构设计以及传动部分的运动和动力设计。本刀库减速传动部分分两级减速,一级传动部分采用同步带轮,二级传动部分采用蜗轮蜗杆减速装置。此种设计方案可提高输出轴的传动平稳性能,保证刀盘的运转平稳性。     

Magazine exposure: Internalization, self-objectification, eating attitudes, and body satisfaction in male and female university students.

Investigated the relationships among magazine exposure, self-objectification, body shape dissatisfaction, and eating disorder symptomatology in 150 men and women (aged 18-42 yrs). Women reading beauty magazines and men reading fitness magazines internalized societal ideals (internalization). For women, beauty magazines predicted self-objectification, mediated by internalization. For men, only internalization predicted self-objectification. For men, fitness magazines predicted body shape dissatisfaction, mediated by internalization. For women, only internalization predicted body shape dissatisfaction. Reading magazines also predicted eating problems for men and women, for women this was mediated by internalization. Findings suggest that magazine reading is related to concerns with physical appearance and eating behaviors. Many of the relationships previously found for women are similar for men. A sociocultural model is used to explain these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

井下爆炸材料库设计布置问题探讨

井下爆炸材料库是矿井安全生产的重要保障设施之一.井下爆炸材料库的设计与相关规定,同现场使用管理存在一定的不明确或矛盾之处.针对设计贮存量、回风道布置、辅助硐室位置与安排、以及库房地板选择等方面,概括分析井下爆炸材料库设计布置中存在的问题,并提出解决问题的相应对策,对规范设计具有指导借鉴意义.     

Polaroid,Aperture and Ansel Adams: Rethinking the Industry-Aesthetics Divide

This article takes the history of Polaroid photography as an opportunity to question a presupposition that underpins much thinking on photography: the split between industrial (i.e. useful) applications of photography and its fine art (i.e. aesthetic) manifestations. Critics as ideologically opposed as Peter Bunnell and Abigail Solomon-Godeau steadfastly maintain the existence of this separation of utility and aesthetics in photography, even if they take contrasting views on its meaning and desirability. However, Polaroid, at one time the second largest company in the photo industry, not only enjoyed close relations with those key representatives of fine art photography, Ansel Adams and the magazine Aperture, but it also intermittently asserted the ‘essentially aesthetic’ nature of its commercial and industrial activities in its own internal publications. The divide between industry and aesthetics is untenable, then, but this does not mean that the two poles were reconciled at Polaroid. While Aperture may have underplayed its commercial connections and Polaroid may have retrospectively exaggerated its own contributions to the development of fine art photography, most interesting are the contradictions and tensions that arise when the industrial and the aesthetic come together. The present article draws on original research undertaken at the Polaroid Corporation archives held at the Baker Library, Harvard, as well as with the Ansel Adams correspondence with Polaroid, held at the Polaroid Collections in Concord, Massachusetts.     

Contributors

Abstract

The Emancipation Proclamation of 1862 marked more than the ostensible freeing of slaves in the United States; it also marked the beginning of a transmigration of black people that would forever alter the culture of the country. Many ex-slaves moved north or stayed in the South; others (far fewer in number) decided to test the American dream of success in the West that stretched from the Mississippi River to California and from Canada to Mexico.     

基于PLC的圆盘式刀库电控系统设计

以复合镗铣加工中心工作时实现加工中心的自动换刀为研究对象,利用三菱FX3U系列PLC完成了圆盘刀库电控系统的设计方案,该系统可以使刀库完成随机选刀、就近换刀等规定动作。经过现场调试,该系统稳定、可靠。     

四轴联动高速加工中心的研制

研制了四轴联动高速加工中心。加工中心采用回转交换工作台，使上料时间与加工时间重合；开发了无级分度伺服转台，可实现对零件任意垂直转台的表面进行加工；X、Y、Z三轴工作台均采用框架式结构，质量较轻、刚性好，并可与伺服转台实现四轴联动。加工中心还配有顶置式圆盘刀库，刀对刀换刀时间为2．5s。电主轴最高转速可达20000r／min。对机械系统的部分参数进行了分析与计算。试加工结果表明，各项技术指标满足设计要求。     

基于非线性干扰观测器的自动弹仓终端滑模控制

针对某自动弹仓位置控制过程中的负载变化和不确定性干扰,设计了基于干扰观测器和非奇异快速终端滑模的复合控制策略,建立了自动弹仓的不确定性动力学模型。干扰观测器用于估计系统复合干扰,估计值用于补偿滑模控制器以增强控制器的鲁棒性和抗干扰能力。运用Lyapunov准则证明了系统闭环稳定。所提算法和PID算法的对比实验结果显示,设计的控制律实现了自动弹仓位置的精确控制,具有良好的鲁棒性,有效提高了自动弹仓的定位稳定性。     

PCB工业“绿色生产”的好形式——建立电子电路“工业园区”的启示

文章概述了在“绿色生产”的挑战下,最佳方案是采用“工业园区”和“技术革命”的道路。从“节能减排”和“制造过程”等角度看,喷墨打印技术／印制电子技术是最有前途的。     

基于VisualBasic数控蓝图编程系统的研制

介绍一种基于VisualBasic数控蓝图编程系统的总体结构、基本功能和主要算法,系统具有自动生成ISO数控加工代码和模拟显示数控加工轮廓的功能。