用JAVA语言处理AutoCAD图形数据的研究

JAVA语言在网络化CAD/CAM中具有其它高级语言不可替代的优势。在分析AutoCAD二维图形的DXF文件特征的基础上,详细讨论了用JAVA语言处理AutoCAD二维图形的方法,包括用JAVA语言提取DXF文件实体数据,并进行排序整理,然后用JAVA语言进行图形的二次显示,最后以事例说明了这种方法在CAD/CAM中的应用。     

以创新谋发展靠标准赢质量——访江苏常发集团农业装备公司品质部长廖汉平

记者：请对常发在拖拉机领域的发展做详细描述。您认为公司的核心竞争力是什么？     

山高: 以更强韧性 应对巨大的不确定性

2020年以来,新冠肺炎疫情全球大流行加速世界变局,全球市场萎缩打乱了经济全球化的.节奏。产业链、供应链在疫情之下受到了威胁,面对巨大的不确定性,山高展现出了更强的韧性。技术创新是山高的优势能力之一,即使在艰难的2020年,山高集团也没有停止产品研发的脚步,没有削减任何研发费用。2020年山高推出了全新的双面旋风刀片,具有先进的粗加工槽型,可以帮助用户减少甚至省略修整工序,同时功耗更低,大大节省单刃成本。Jetstream Tooling(JETI)刀杆扩展系列能在加工钢件、不锈钢和超合金材料时,让所有车削应用获得更长的刀具寿命和更好的切屑控制。优势产品在客户端获得积极反馈,MDT槽刀产品销量增长20.8%,三面刃铣刀增长27.5%。QC模块化接口刀杆荣获荣格技术创新奖。     

自制分度装置加工大型花键丝杠

我公司承制了吉马中板厂十一辊矫直机,其中在制造矫直机的压下装置时碰到一个难题。压下装置的功能是通过丝杠螺母的传动,将上工作辊压下和提起,从而完成钢板的矫直工作。压下装置的主要构件是压下丝杠(如图1所示),其主动端为10等分、键宽为30mm的矩形花键,从动端为S360×16-9e的锯齿形螺纹。此矩形花键长度为660mm,花键的对称度、尺寸精度、表面光洁度等要求都很高,如何保质、保量地加工出此花键成了制定工艺和加工的难题。1工艺分析此压下丝杠总长为1805mm,重量为1046kg,根据本公司设备的加工能力,此工件只能在X2012A龙门铣床上加工花键…     

Robots with increased number of degree-of-freedom with single exciting force

This paper presents the results of the development and investigation of a new class of novel multi-degree-of-freedom robots based on a new concept – the application of kinematic pairs with alternating degree-of-freedom (DOF) controlled by a single force or moment, changing its direction in space. The number of DOF of the kinematic pairs is controlled periodically from 0 to 3, exploiting the dependence of frictional forces on the oscillation in the contact zone of links. The advantages of this new class of robots include significant weight reduction, simple design and control, and specific applications in space robotics and soft robotic spines. In more complicated cases of trunk robots, elastic kinematic pairs are used with a number of DOF controlled by electro- or magneto-rheological fluids with viscosities that change as a result of applied electric or magnetic fields. Expressions for the generalized inertia matrix of the robots with a large number of joints have been derived using the computer algebra technique with the subsequent automatic program code generation. As shown in this paper, such an application could drastically reduce the number of floating point product operations for an efficient numerical simulation of robots.     

有创-无创序贯机械通气治慢性阻塞性肺疾病合并呼吸衰竭患者疗效

目的:观察应用有创-无创序贯机械通气方法治疗COPD合并呼吸衰竭患者的疗效。方法 :以2010年2月至2010年12月在我院接受治疗的慢性阻塞性肺疾病(COPD)合并呼吸衰竭76例患者为研究对象,随机分为2组。对照组行有创正压通气治疗,治疗组行有创机械通气达到切换点拔管后继续行无创序贯通气治疗。观察两组患者机械通气时间、住院时间、脱机成功率、呼吸机相关性肺炎(VAP)发生率等指标。结果 :治疗组与对照组的VAP发生率分别是3例(7.89%)和10例(26.31%),脱机成功率分别是36(94.73%)和30(78.94%),机械通气时间分别是(11.01±3.71)d和(14.77±3.53)d,总住院时间分别是(17.50±3.67)d和(20.32±4.15)d,2组各项指标差异有统计学意义P<0.05。结论 :在PIC窗指导下有创-无创序贯通气治疗,能显著减少通气时间,缩短住院时间,提高脱机成功率,降低VAP发生率,提高患者抢救成功率。     

Friction of Rubber with Surfaces Patterned with Rigid Spherical Asperities

This paper reports on the frictional properties of smooth rubber substrates sliding against rigid surfaces covered with various densities of colloidal nano-particles (average diameter 77 nm). Friction experiments were carried out using a transparent poly(dimethyl siloxane) (PDMS) rubber contacting a silica lens with silica nano-particles sintered onto its surface. Using a previously described methodology (Nguyen et al., J Adhesion 87:235?C250, 2011), surface shear stress and contact-pressure distribution within the contact were determined from a measurement of the displacement field at the surface of the PDMS elastomer. Addition of silica nano-particles results in a strong, pressure-independent enhancement of the frictional shear stress as compared to the smooth lens. The contribution of viscoelastic losses to these increased frictional properties is analyzed in the light of a numerical model that solves the contact problem between the rubber and the rough surface. An order-of-magnitude agreement is obtained between experimental and theoretical results, the latter showing that the calculation of viscoelastic dissipation within the contact is very sensitive to the details of the topography of the rigid asperities.     

双泵配蓄能器节能系统

采用双泵配蓄能器的节能装置以改进挤管机液压系统。     

对话塔海尔:China＆Vision--塔海尔集团上海首代江浩访谈

日前塔海尔集团决定将东北亚地区总部从香港转移到上海,2003年10月塔海尔集团上海代表处在上海正式成立,江浩出任首席代表并兼任塔海尔集团中国和韩国区域总监,近日江浩先生应邀作客本期GM论坛,与通用机械杂志社记者曾江、博乐做了互动交流。     

水切割

水是用在工业生产中最万能的切割刀具之一.无论是纸,塑料或金属,几乎任何材料都可以用水喷射切割,而且是一种特别经济的方法.     

磨削外圆与内孔不同心的套类工件

我们知道内孔与外圆同心的套类零件,只要配作 一个芯轴即可实现外圆磨削,而内孔与外圆不同心的套类零件(如图1所示)的外圆磨削却有一定困难。如果我们只采用一个偏心芯轴来实现外圆磨削,由于芯轴     

中国"大脑"装备中国--访武汉华中数控股份有限公司董事长陈吉红先生

近几年,位于长江之滨的以生产中高档数控系统为主的武汉华中数控股份有限公司,凭借其达到国际领先水平且具有自主版权的数控技术和现代化的产业基地,在中国大地迅速崛起,成为国外公司强劲的竞争对手.研制生产的具有完全自主知识产权的华中高性能数控系统,可以实现4通道、16轴控制、9轴联动,独创的SDI五坐标曲面直线插补技术属国际首创.华中高性能数控系统的诞生,打破了西方发达国家对中国的技术封锁和出口控制,受到国家和地方政府领导的关怀和重视.华中数控这匹驰骋在数控系统疆场的快马,给我国数控系统产业带来了一片曙光.     

Static strength test with as-forged control-arm in automobile with Mg-Al-Sn-Zn alloy

This paper mainly concerns application of the Mg-Al-Sn-Zn alloy to the control-arm of an automobile with warm-forging process since Mg-Al-Sn-Zn alloy (ATZ842) exhibits enhanced strengths in tension and compression as well as the improved YR reaching 1.0. In order to validate the Mg control-arm, two wrought Mg alloys such as AZ80 (Mg–7.45wt% Al–0.38wt% Zn) and ATZ842 (Mg–7.59wt% Al–3.96wt% Sn–1.94wt% Zn) alloy have been produced with casting and extrusion processes, which have been applied to warm-forging of the Mg control-arm. As-forged two Mg control-arms with AZ80 and ATZ842 alloys have been evaluated with the static strength test to measure the maximum reaction force under the quasi-static compressive deformation. It is highly recommended to adopt the ATZ842 control-arm forged at 250°C since it does not only have comparably high reaction force in the static strength test, but also demonstrates fine grain structure if the abnormal grain growth is suppressed during the warm-forging process.

     

固定开关频率电流控制PWM整流器的研究

针对高压大功率电机的控制,介绍了一种基于固定开关频率电流控制方法的PWM整流器,对其具体控制算法及电路参数的计算进行了研究。并在Matlab-Simulink下建立了系统的仿真模型,最后代入实际参数进行了仿真,验证了其可行性。     

有限缓冲区流水线调度的多搜索模式遗传算法

针对有限缓冲区流水线调度问题,提出了一种多搜索模式遗传算法,算法使用多个交叉和变异操作进行解空间的探索和改良,并采用基于有向图的邻域结构来增强局部搜索。同时,局部搜索和变异操作受决策概率控制。基于典型算例的仿真和比较研究验证了所提算法的有效性。