多层烧结超硬磨料工具现状综述与未来发展构想

综述了当前针对多层烧结超硬磨料工具磨料易脱落、磨料出刃难、磨料出刃后出露程度保持难以及磨料的随机分布导致工作面上磨料负荷与磨削过程的失衡所采取的相关对策与措施。介绍了已开发成功的新一代单层钎焊超硬磨料工具及其带来的启示。提出了以钎焊代替烧结,借鉴多孔金属材料生产工艺开发磨料与孔穴三维协同择优排布制造多层烧结超硬磨料工具换代产品的新构想。     

“Mapping” Smart Cities

ABSTRACT

Smart cities are designed to use data to optimize resources, maintain sustainability, and improve people’s quality of life. While many urban technologies are employed to make cities “smart,” one constellation of technologies has been less examined in the academic literature—digital maps and the spatial data infrastructure. This paper is an attempt to systematically review the functions and evolution of digital maps and the spatial data infrastructure, with examples from Asia and beyond, in supporting and making smart cities possible. Based on the conceptual framework and empirical case studies, four major research directions of smart mapping are identified to better support smart city initiatives.     

福州火车站站前地下广场建筑设计

本文通过福州火车站站前地下广场工程建筑设计实践,论述了在地下空间建设复杂的交通枢纽及综合商业建筑工程的可能性和现实意义。     

长治市小杂粮产业现状及发展思路

阐述了长治市小杂粮产业的发展现状,分析了存在的问题,并提出了发展思路,包括增加资金支持,广泛宣传,推行标准化生产,搞好新品种、新技术的试验、示范、推广工作等方面的内容,以供参考。     

Integrated Train Ground Radio Communication System Based TD-LTE

In existing metro systems, the train ground radio communication system for different applications are deployed independently. Investing and constructing the communication infrastructures repeatedly wastes substan-tial social resources, and it brings di?culties to maintain all these infrastructures. We present the communication Quality of service (QoS) requirement for different train ground radio applications. An integrated TD-LTE based train ground radio communication system for the metro system (LTE-M) is designed next. In order to test the LTE-M system performance, an indoor testing environment is set up. The channel simulator and programmable attenua-tors are used to simulate the real metro environment. Ex-tensive test results show that the designed LTE-M system performance satisfies metro communication requirements.     

XRF法快速测定铝土矿火车样

采用压样法，使用国产便携式Ｘ射线光分析仪快速测定铝土矿火车样中的铝、硅、磷、硫、钾、钙、铁、钛８个元素。文章对标样的采集、制样、仪器某些性能的改进，各种影响因素的校正（如基体效应、谱叠加干扰等）、数学模型的研究开发等作了简要说明，提出了解决问题的基本原则，在小型仪器上攻克了铝土矿火车样工业分析的难题。该技术具有准确、快速、成本低的优点。     

Finishing characteristics of brittle materials by ELID-lap grinding using metal-resin bonded wheels

ELID-lap grinding is a method of constant pressure grinding which utilizes an electrically conductive wheel and the electrolytic in-process dressing (ELID) method. This method has the advantage of using micro grain-wheels above #10 000 and also, through simple modification, can be used on existing lap machines. To find the characteristics of metal-resin bonded wheels developed for ELID-lap grinding, experiments on the grinding of brittle materials were performed using wheels with a variety of grain diameters. The wheels used in the experiments were #8000, #120 000 and #3 000 000 metal-resin bonded diamond wheels (#8000 MRB-D, #120 000 MRB-D and #3 000 000 MRB-D wheels). The workpieces were silicon and glass. The results of the experiments showed that stable grinding can be achieved with the #8000 to #3 000 000 MRB-D wheels. With the #3 000 000 MRB-D wheel, very smooth surface finishes were obtained for both silicon (PV 2.8 nm) and glass (PV 2.5 nm). Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) observations indicated these surfaces to be very smooth in the order of several nanometers, obtained by mechanical removal using an ultrafine wheel.     

轮轨关系研究中的力学问题

简单论述世界铁路发展状况和铁路交通运输的优越性。详细论述轮轨关系的研究问题,其研究包含轮轨滚动接触作用和稳定性问题、轮轨粘着和强度、接触表面磨损和滚动接触疲劳破坏、轮轨噪声、轮轨蠕滑率／力理论和轮轨三维弹塑性滚动接触问题。在这些问题研究中,蕴涵十分复杂的力学和强度问题。文中就这方面的研究现状和存在问题以及问题研究的难点进行讨论,并分析今后可能的研究方向。     

纵向磨削砂轮堵塞的试验研究

本文研究了纵向外圆磨削中,工件转速,修速速度,走刀量,磨削厚度及冷却液对硝轮堵塞深度和而积的影响。初步探讨了纵磨时,砂轮堵塞的基本规律。     

杯状砂轮修整器对CBN砂轮的修形及磨削

研究杯状砂轮对陶瓷ＣＢＮ砂轮的修形,及修形后磨削高速钢和软钢的加工特性。通过研究得出,磨削高速钢时砂轮磨粒磨损和切屑附着、磨削软钢时砂轮表面发生堆积物熔着是砂轮磨耗的主要原因。