Design of Automatically Programmed System for Punching and Shearing and Its Key Technology

冲裁加工广泛应用于金属薄板件的加工。论文根据敏捷制造的先进制造技术理念，以制造单元－冲裁加工为研究对象，通过对二维数控冲裁薄板工件的工艺过程和加工特点分析，基于AutoCAD图形信息，研发了一套适合冲裁加工制造单元的数控冲床自动编程软件系统（Punch-CAM）。本系统的开发有助于通过对传统冲床的数字化改造，实施多品种、小批量产品的敏捷制造，从而为薄板工件冲裁加工的数字化和网络化制造奠定了一定基础。通过自动编程和动态仿真的实现，大大提高了数控编程的效率，降低了编程难度和劳动量；提高了生产效率和安全性，避免了加工中的误操作，完全避免了编程中的误操作；有助于生产过程中的自动化。论文通过对工件常有的...Machining of punching and shearing as a manufacturing cell is widely used for the metal sheet manufacturing．According to one of the advanced manfacturing technology theory -- thought of agile manufacturing, the thesis develops an Automatically Programmed System( named as Punch-CAM) for NC machining of punching and shearing．The system analyses the technical process and the machining characteristic ...学位：工学硕士院系专业：物理与机电工程学院机电工程系_测试计量技术及仪器学号：20032902

Research on NC Machining Technology Based on Cutting Tool with Forward and Backward Motion

通过分析常规数控加工中存在的问题,提出了一种刀具在进给方向上可进让式进给切削工件曲面轮廓的新工艺方法,建立了进让式进给切削数学模型,并从被加工工件的几何形状、切削过程中刀具受力情况及切削区的切削热释放情况等方面,具体分析了采用该方法对加工精度的改善情况,并给出了算法步骤。试验结果表明,新方法有利于减小工艺系统的变形,显著提高了工件的加工精度。Based on analyzing problems that general NC machining process existed,this paper proposed a machining method of cutting tool forward-and-backward machining work piece in feed direction.The calculation model of cutting location was established,and the advantages of this process included a superior surface finish,low tool pressure and cutting heat released easily in the cutting section.Finally,experiments and data were shown.The advantages were illustrated by reducing deformation of machining complex and achieving higher machining precision.校引进人才科研启动资金项目(ZRC2008221

Research on NC machining technology based on cutting tool creep-feed in feed direction

【中文文摘】通过对数控加工中存在的问题分析,提出了一种在数控加工中,刀具在被加工工件曲面上沿进给方向蠕动式切削加工的方法,通过刀具与工件时续分离和切削,改善了工艺系统的刚性,从而使工件的加工精度得到改善,并具体从被加工工件的几何形状、切削过程中刀具受力情况及切削区的切削热释放情况方面,分析了采用该方法对加工精度的改善情况。 【英文文摘】Based on analyzing problems that general NC machinining process exists, this paper proposes a machining method cutting tool creep-feed machining work piece in feed direction .When cutter is fed toward and away from work piece,it can improve the rigidity of mechanics system,so that machining precision is improved. Other advantages of this process include a superior surface finish,low tool pressure, and cutting heat released easily in the cutting section

First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring

In a companion paper, we present the first spatially resolved polarized image of Sagittarius A* on event horizon scales, captured using the Event Horizon Telescope, a global very long baseline interferometric array operating at a wavelength of 1.3 mm. Here we interpret this image using both simple analytic models and numerical general relativistic magnetohydrodynamic (GRMHD) simulations. The large spatially resolved linear polarization fraction (24%–28%, peaking at ∼40%) is the most stringent constraint on parameter space, disfavoring models that are too Faraday depolarized. Similar to our studies of M87*, polarimetric constraints reinforce a preference for GRMHD models with dynamically important magnetic fields. Although the spiral morphology of the polarization pattern is known to constrain the spin and inclination angle, the time-variable rotation measure (RM) of Sgr A* (equivalent to ≈46° ± 12° rotation at 228 GHz) limits its present utility as a constraint. If we attribute the RM to internal Faraday rotation, then the motion of accreting material is inferred to be counterclockwise, contrary to inferences based on historical polarized flares, and no model satisfies all polarimetric and total intensity constraints. On the other hand, if we attribute the mean RM to an external Faraday screen, then the motion of accreting material is inferred to be clockwise, and one model passes all applied total intensity and polarimetric constraints: a model with strong magnetic fields, a spin parameter of 0.94, and an inclination of 150°. We discuss how future 345 GHz and dynamical imaging will mitigate our present uncertainties and provide additional constraints on the black hole and its accretion flow

Study on helical flute grinding virtual simulation of twist drill

分析加工麻花钻时螺旋槽与砂轮的几何运动关系,运用微分几何和运动学原理建立螺旋槽和砂轮的数学模型。在此基础上,利用Vb对AuTOCAd软件进行二次开发,建立了麻花钻螺旋槽三维磨削虚拟仿真加工模型,对给定参数的麻花钻进行了几何参数、刀具参数及机床运动参数的计算,并进行了虚拟仿真加工,验证了三维磨削虚拟仿真加工模型的正确性。By analyzing the geometric motion relationship between the helical flute and the grinding wheel when grinding the twist drill,the mathematical model of the helical flute and the grinding wheel was established by applying differential geometry and kinematics principle.Based on this,the secondary development of AutoCAD software was carried out by using VB,and the helical flute three-dimensional virtual simulation grinding model of the twist drill was set up.The computation of the twist drill geometry parameters,cutter parameters and grinder movement parameters were carried out,and the virtual simulation grinding was completed.The correctness of the virtual simulation grinding model was proven.校引进人才科研启动资金资助项目(ZRC2008221

2001～2010年科技兴新基本思路与对策研究

新疆连续制订两个《科技兴新纲要》来指导两个十年的科技兴新工作，在1991年发布实施的《科技兴新纲要》中确立的主要任务是科技兴农、科技兴工和以科技为先导的矿产资源勘查与开发的基础上，为了适应我区经济社会发展和国家实施西部大开发的需要，增加了科技兴贸、以科技为先导的环境保护和实施科技兴新四大工程等内容。新的《科技兴新纲要》体现了在国家实施西部大开发中强化实施科技兴新工作的特点。国家实施西部大开发的重点是产业结构调整、生态环境建设与保护、特色资源开发、基础设施建设等内容，为我区实施科技兴新工作提出了明确的目标和提供了广阔的舞台。今后十年，《科技兴新纲要》规划的主要任务中，都涵盖了为这些重点提供技术支撑和服务的内容

不同覆盖物对果树越冬的保温作用/The Heat Preservation Effects of Different Coverings for Fruit Trees' Overwintering[J]

在克拉玛依市乌尔禾区,于2006～2007年冬季,采用不同覆盖材料,进行了黑塑料布、双膜彩条布、单膜彩条布和紧贴式双层塑料布覆盖下的最低温度和温差的逐日观测,以减轻果树越冬掩埋的劳动强度.结果表明:最低气温平均值是黑塑料布-5.9℃,双膜彩条布-7.3℃,单膜彩条布-9.3℃,紧贴式双层-6.6℃,裸露的气温-17.9℃.温差平均值是黑塑料布-2.8℃,双膜彩条布-2.6℃,单膜彩条布-4.8℃,紧贴式双层-3.7℃,裸露的气温-10.0℃.试验表明,黑塑料布的保温效果好,温差也小.单膜彩条布的保温效果最差,温差也最大,有转暖乍冷的不良影响.紧贴式双层塑料布的保温效果因为与单层黑塑料布相同,并且多浪费一层覆盖材料和多费工时而被否定

果树越冬不同覆盖方法的成本计算/The Cost Calculation of Different Coverings for Fruit Trees ' Overwintering[J]

为减轻果树越冬掩埋的劳动强度,推广塑料膜防寒覆盖法,对土埋和白塑料布、黑塑料布、彩条布覆盖的劳动力和材料成本进行了对比分析.结果表明:蟠桃土埋法需要强壮劳动力1700元/667m2,塑料薄膜法只需要强壮劳动力450元/667m2;加材料费合计:白塑料布单层覆盖690.0元/667m2,双层覆盖930.0元/667m2；黑塑料布单层覆盖814.8元/667m2,双层覆盖1179.6元/667m2；彩条布单层覆盖862.8元/667m2,双层覆盖1275.6元/667m2.葡萄土埋法需要强壮劳动力2.92元/m；塑料薄膜法只需要强壮劳动力0.74元/m,加材料费合计:白塑料布单层覆盖1.24元/m,双层覆盖1.74元/m;黑塑料布单层覆盖1.50元/m,双层覆盖2.26元/m；彩条布单层覆盖1.60元/m,双层覆盖2.46元/m.塑料薄膜法比土埋法便宜,其中白塑料布更便宜.同时提出,在环塔里木主产区和吐哈区的暖温带,应该根据气象部门秋季的长期天气预报,一般年份用单层覆盖都能安全越冬,预报寒冬的年份,应该进行双层覆盖.在中温带的北疆沿天山一带产区,也应根据气象部门秋季的长期天气预报,一般年份用单层覆盖都能安全越冬,预报寒冬或者晚降雪的年份,应该进行双层覆盖

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel