薄壁金刚石工程钻头激光焊接技术及装备

深入探讨了薄壁金刚石工程钻头激光焊接的技术及装备发展现状及趋势。针对金刚石钻头结构特点和焊接工艺特点,综合分析了德国Dr．Fritsch公司、韩国Diex公司及华中科技大学激光加工国家工程研究中心研制生产的三种激光焊接装备的结构,包括基体、刀头的传送、夹紧、焊接方式。总结了目前国际上广泛采用的板条、轴快流、横流CO_2激光器的特点及其成套系统的匹配性。     

薄壁金刚石工程钻头激光焊接技术及装备

深入探讨了薄壁金刚石工程钻头激井焊接的技术及装备发展现状及趋势.针对金刚石钻头结构特点和焊接工艺特点,综合分析了德国Dr.Fritsch公司、韩国Diex公司及华中科技大学激光加工国家工程研究中心研制生产的三种激光焊接装备的结构,包括基体、刀头的传送、夹紧、焊接方式.总结了目前国际上广泛采用的板条、轴快流、横流CO2激光器的特点及其成套系统的匹配性.     

基于MCS-51单片机和PC机的热压机自动控制系统的研究与开发

热压成型是制造金刚石合金钻头的一个非常重要的工艺过程,鉴于目前实际应用中的热压机存在的不足和缺陷,为了能够实现金刚石钻头烧结过程的自动控制,研究了一种基于单片机和PC机的新型热压机控制系统,介绍了该系统的软件设计和硬件设计.试验证明该控制系统能有效的跟踪压力和温度工艺曲线,控制精度高,稳定性好.该系统的研制成功,为制定更加合理的金刚石钻头烧结工艺打下了基础.     

真空扩散焊焊接PDC钻头的可行性

分析了PDC钻头使用过程中存在的问题及其产生的原因,探讨了PDC钻头真空扩散焊方法及工艺的可行性,证明了利用真空扩散焊进行聚晶金刚石复合体焊接来提高PDC钻头的使用性能和寿命是可行的.     

电沉积金刚石钻头的结构优化设计与试验

在钻削高硬度材料时，钻头结构的合理选择关系到工件钻削的加工效率和成本。对钻削过程中的钻头磨损及寿命进行分析，并对不同结构的电沉积金刚石钻头使用有限元软件进行仿真分析及优化，以提高电沉积金刚石钻头在钻削SiC陶瓷材料时的钻削性能。从多个角度分析排屑对于提高电沉积金刚石钻头钻削高硬度陶瓷材料的可钻削性和钻头寿命的重要性，通过两种试验得出钻削扭矩、钻头磨损、工件表面质量与钻头结构的关系趋势，并据此设计出最佳电沉积金刚石钻头结构。     

金刚石钻头的研究与应用现状

随着新型复合材料的应用日益广泛,以及精密和超精密加工技术的不断进步,金刚石刀具获得了迅速发展。本文对包括电镀型金刚石钻头、钎焊式金刚石钻头、CVD金刚石钻头、聚晶金刚石（PCD）钻头在内的各种金刚石钻头的研究和应用现状进行了综合评述。     

复合片钎焊可编程序控制系统

针对某钻头厂对复合片采用手工焊接,焊接温度以及焊接时间完全依靠经验,焊接质量难以保证,焊接效率低的现状,研制了自动焊接温度控制系统,通过PLC对焊接温度、焊接时间等进行自动控制,提高了焊接效率,保证了焊接质量.     

聚晶金刚石复合体（PDC）焊接工艺研究

PDC既具有金刚石的高硬度、高耐磨性,同时具有硬质合金良好的抗冲击韧性,被广泛应用于钻头、切削刀具等.对PCD的焊接工艺进行了研究,将PDC焊接温度控制在700 ℃以下,能保证复合片上的聚晶金刚石层不失效,使其在长期作业过程中具有良好的使用性能.     

特种金刚石钻头的研制

介绍一种新研制的能把超声振动和金刚石磨粒磨削结合在一起的特种金刚石钻头。阐述了该钻头的钻削机理及设计制作过程。试验表明，该钻头是钻削工程陶瓷、宝石等硬脆材料的理想工具。     

适应深孔条件的孕镶金刚石钻头分析

为解决深孔硬岩地层钻探施工中存在的钻头磨损、钻探效率低问题,本文通过对孕镶金刚石钻头及其磨损形态进行分析,围绕金刚石选取与预处理、钻头胎体配方改进设计、烧结模具与工艺优化三个层面,探讨了孕镶金刚石钻头的改进设计方案,提出适应深孔条件的孕镶金刚石钻头,旨在为钻探施工提供参考。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.