用模拟微波设备传送数字压缩电视信号的可能性

数字电视压缩技术已经成熟。能否在现有的广播电视专用模拟微波接力电路上传送数字压缩电视信号已成为关注的课题。本文就有关技术问题提出自己的看法。     

影响钢丝绳疲劳寿命的几种因素

引入了钢丝绳疲劳试验定义。大量试验证实 :索氏体化率高、组织均匀的材质 ,结合紧密、丝径较粗的线、面接触结构 ,适宜的强度和韧性 ,适当的预变形处理 ,均匀充分的润滑 ,并配合直径较大、轮槽喷涂或衬胶的滑轮可以有效地提高钢丝绳的疲劳寿命     

科氏力秤入窑生料计量与控制系统

介绍一种应用科里奥利力学原理的入窑生料计量系统.该系统的研制与开发,改写了多年来只能依赖冲量式流量计计量入窑生料的历史.为入窑生料计量提供了新的技术和手段.运行数据表明:该系统计量准确度优于±1%,入窑生料提升机电流波动范围＜±1%;这一计量系统同样可用于其它大流量干粉粒状物料计量,如散装水泥,火车、轮船,散装粉粒状发运等计量环节,应用前景广阔.     

Investigation on MoS2 and graphite coatings and their effects on the tribological properties of the radial spherical plain bearings

With constant enlargement of the application areas of the spherical plain bearings, higher quality lubrication of the bearings is required. To solve the lubricating problems of spherical plain bearings under high temperature, high vacuum, high speed, heavy loads and strong oxidation conditions, it is urgent for us to develop more excellent self-lubricating technologies. In this paper, the bonded solid lubricant coatings, which use inorganic phosphate as the binder, the mixture of MoS2 and graphite with two different weight proportions as the solid lubricant, are prepared by spraying under three different spray gun pressures. The bonding strength tests on the coatings show that the best spraying pressure is 0.2 MPa and the better mixing proportion of MoS2 to Graphite is 3:1. Then for the radial spherical plain bearings with steel/steel friction pair, after the coatings are made on the inner ring outer surfaces, the friction coefficient, the wear loss and the friction temperature of the bearings under four oscillating frequencies are investigated by a self-made tribo-tester. The test results, SEM of the worn morphologies and EDS of worn areas show that tribological properties of the bearing are obviously improved by the bonded solid lubricant coatings. When sprayed under the spray gun pressure of 0.2 MPa, the bearings have better anti-friction and anti-wear properties than those sprayed under 0.1 MPa and 0.3 MPa. Further as proved from the XPS analysis, between the coating with 3:1 mixing ratio of MoS2 to Graphite and the coating with 1:1 ratio, the former has less oxidation occurred on the surface and therefore has better tribological characteristics than the latter. This paper provides a reference to developing a new product of the radial spherical plain bearings with high bonding strength, oxidation resistance and abrasion resistance.     

EFFECT OF HYDROGEN ON MECHANICAL PROPERTIES OF A HIGH DENSITY W-Ni-Fe ALLOY

研究了液相烧结钨基高比重合金(95W-3.5Nj-1.5Fe)烧结后热处理对力学性能的影响.经过1200℃真空热处理,合金中氢含量降低了70％,强度提高约30％,延性显著增加,同时断裂韧性值也有提高。通过扫描电镜断口金相观察,发现氢含量高的试样显示了基体-钨颗粒相界面断裂,对氢含量低的试样,断口微观形态由沿相界面断裂方式过渡到相界面断裂和部分钨颗粒解理断裂方式,说明削弱了氢脆,加强了相界面结合力,从而改善了合金的力学性能。对氢含量高的试样,作了离子探针分析,其结果指出钨颗粒周围含氢最较高,相界面有氢的富集,它是导致相界面断裂的根源。     

地铁保护区范围内的深基坑支护施工

结合工程实际,对地铁保护区范围内深基坑的支护施工进行了研究.通过采用钻孔灌注桩+预应力锚索+钢支撑组合支护方式,顺利完成了地铁保护区范围内的深基坑支护工作,实施效果良好,既保证了深基坑的稳定,又减小了对既有地铁的影响.实践证明,该支护方式技术工艺完善,具有安全、经济、施工方便等优势.     

TS现场模板浇注发泡聚氯酯外保温成套技术

现场模板浇注发泡聚氨酯技术在外墙保温工程中优于喷涂技术。文章从现1场模板浇注聚氨酯外保温技术要从保温材料综合性能、滑模板及防粘、浇注工艺、设备性能及形成完整外保温构造、工程技术等进行系统工程研究。     

基于虚拟仪表技术的转速闭环变频调速自动飞锤试验台的设计

设计制造了用于测试柴油机喷油泵飞锤特性试验的飞锤试验台。试验台采用变频驱动交流异步电机带动飞锤,上位机采用组态软件Labview进行编程。本试验台可用于带机械调速器的喷油泵进行出厂试验和性能试验。     

柴油机相继增压系统设计及性能模拟

随着增压压力的提高，高增压柴油机低负荷问题日益突出。作为有效的解决方案之一本文对相继增压系统进行了模拟研究，同时对该系统设计上的一些问题进行了讨论。     

DBPM signal processing with field programmable gate arrays

DBPM system performance is determined by the design and implementation of beam position signal processing algorithm.In order to develop the system,a beam position signal processing algorithm is implemented on FPGA.The hardware is a PMC board ICS-1554A-002(GE Corp.)with FPGA chip XC5VSX95T.This paper adopts quadrature frequency mixing to down convert high frequency signal to base.Different from conventional method,the mixing is implemented by CORDIC algorithm.The algorithm theory and implementation details are discussed in this paper.As the board contains no front end gain controller,this paper introduces a published patent-pending technique that has been adopted to realize the function in digital logic.The whole design is implemented with VHDL language. An on-line evaluation has been carried on SSRF(Shanghai Synchrotron Radiation Facility)storage ring.Results indicate that the system turn-by-turn data can measure the real beam movement accurately,and system resolution is 1.1μm.