安钢250／300轧钢机组加热炉循环水工程改造

安钢２５０／３００轧钢机组加热炉一次性水冷却改为软水闭路循环水冷却系统,保证了政党生产,节约了水资源,减少了外打破常规水量,保护了生态环境,同时降低了加热炉的故障率,减少了维修费用,提高了经济效益。     

焙烧炉天然气燃烧自动控制系统的研究与应用

介绍了炭素焙烧炉燃烧系统的改造,新型控制系统的功能介绍、使用效果和效益分析,通过改造真正实现了清洁生产,达到了节能效果,改善了工艺水平,提高了产品质量,降低了生产成本,提高了生产效率,改善了工作环境。     

轧钢加热炉改造

针对轧钢加热炉加热能力不足,炉墙冒火,自动化控制水平落后的情况,对加热炉进行了改造,延长了加热炉的长度,更换了单蓄热式空气烧嘴,并对自动控制系统进行了升级改造,从而消除了炉墙冒火的现象,提高了加热能力和自动控制水平,降低了煤气消耗,取得了良好的经济效益。     

提高烧结配料生石灰消化除尘效果的生产实践

通过对烧结配料生石灰消化除尘系统进行改造,提高了除尘效果,同时稳定了生石灰配加量和消化打水量;充分回收利用了消化蒸汽和二次扬尘,减少了资源浪费,提高了消化水温,进一步强化了生石灰消化作用,提高了混合料制粒效果和混合料料温;极大地改善了配料室工作环境,有效降低了检修劳动强度,提高了设备作业率。     

冷床上卸钢液压系统改造

对原液压系统设计及使用中存在的问题 ,进行了分析、计算 ,找出了原因所在 ,提出了改造方案 ,从而有效地提高了液压系统的稳定性 ,减少了设备故障 ,降低了维护强度 ,提高了工作效率。     

民主革命时期中国共产党农业政策对政局的影响

民主革命时期,中国共产党在充分调研基础上制定的农业政策使其社会动员能力发挥到极致,成功地调动了占中国人口绝大多数的农民的政治斗争热情,巩固了中国共产党政权的政治基础;其农业政策调动了农民的生产积极性,发展了农业生产力,保证了战争条件下的军粮民食供给,奠定了革命胜利的经济基础;其农业政策改变了农村阶级力量对比,颠覆了传统农村社会秩序,完成了农村社会秩序的重建,莫定了新民主主义革命胜利的社会基础,最终夺取了全国政权.     

浅议矿脉变化规律与探矿方法

概要介绍了樟东坑矿区的主要地质特征,在前人工作的基础上,对矿床的基本特征(尤其是矿脉的变化特征)进行了分析、探讨和总结;利用这些特性及其变化规律,采用一些新的探矿方法不但找到了一些隐伏盲矿,增加了地质储量,延长了矿山的服务年限,而且降低了探矿费用,减少了采矿的盲目性,节约了成本,增加了经济效益。     

RTK和全站仪联合采集数据模式在安钢GIS中的应用

介绍了RTK和全站仪联合采集数据模式在安钢GIS中的应用情况,通过两种测绘技术的优势互补,简化了程序,提高了效率,减少了误筹,保证了测绘精度,节省了人力和物力.     

炼钢氧枪系统的改造及应用

炼钢厂转炉扩容后对氧枪系统进行了改造,重新设计了氧枪尺寸及喷头,改造了氧枪输送管路与控制系统,优化了各项工艺参数。氧枪改造后,提高了供氧强度,缩短了冶炼周期,溅渣效果良好,增加了经济效益。     

莱钢铁路运输组织工艺的应用

分析了莱钢铁路运输组织工艺的现状,调整了流程,优化了运输组织工艺,提高了运输效率,增加了运输收益。     

浅谈变频器的电磁干扰

介绍了变频器的自身干扰、外界设备对变频器的干扰及变频器对电源的干扰现象、成因及解决办法.     

位移传感器在热轧机中的应用

位移传感器对于保证热轧机的轧制精度有重要作用.介绍了位移传感器的原理、控制系统的检测方法以及位移系统在轧机中的应用等.通过改造,位移传感器成功安装在某中试工厂400 mm热轧机上.一段时间的运行表明,位移传感器工作稳定,完全满足带钢轧制的要求.     

变频器在连铸机械剪机上的应用

本文叙述了广钢转炉厂连铸剪切机为何要使用变频器进行技术改造和变频器的工作原理等，并对连铸剪切机在使用变频器后的实际效益进行了估算。     

精轧液压活套压力传感器故障快速判断与更换

武钢薄板坯连铸连轧生产线生产节奏快,而精轧液压活套压力传感器工作环境差,温度高,容易损坏,故障处理和更换时间过长甚至造成断浇。通过对液压活套压力传感器故障的判断、分析,研制出一种快速更换压力传感器的方法,即测压头、测压线以及传感器外挂的方法。实施此方法以后,彻底消除了因液压活套压力传感器引起的连铸断浇。     

The Development and Validation of Scales Assessing Students'' Achievement Goal Orientations

Conventional ultrasound scanners utilize electronic transmitters and receivers at the scanner with a separate coaxial cable connected to each transducer element in the handle. The number of transducer elements determines the size and weight of the transducer cable assembly that connects the imaging array to the scanner. 2-D arrays that allow new imaging modalities to be introduced significantly increase the channel count making the transducer cable assembly more difficult to handle. Therefore, reducing the size and increasing the flexibility of the transducer cable assembly is a concern. Fiber optics can be used to transmit signals optically and has distinct advantages over standard coaxial cable to increase flexibility and decrease the weight of the transducer cable for larger channel numbers. The use of fiber optics to connect the array and the scanner entails the use of optoelectronics such as detectors and laser diodes to send and receive signals. In transmit, optoelectronics would have to be designed to produce high-voltage wide-bandwidth pulses across the transducer element. In this paper, we describe a 48 channel ultrasound system having 16 optoelectronic transmitters and 32 conventional electronic receivers. We investigated both silicon avalanche photodiodes (APD's) and GaAs lateral photoconductive semiconductor switches (PCSS's) for producing the transmit pulses. A Siemens SI-1200 scanner and a 2.25 MHz linear array were used to compare the optoelectronic system to a conventional electronic transmit system. Transmit signal results and images in tissue mimicking of cysts and tumors are provided for comparison.     

基于六端网络法的压电超声换能器优化设计

压电超声换能器传统四端网络设计方法忽略了压电陶瓷晶堆内部的机电耦合过程，使用该方法所设计的压电超声换能器尺寸误差大，输出的超声振幅较小。为了提高压电超声换能器尺寸设计精度、增大换能器输出的超声振幅，本文将考虑压电陶瓷晶堆内部机电耦合作用的六端网络引入到压电超声换能器的设计中，分别采用四端网络法和六端网络法设计得到两个不同尺寸的压电超声换能器A和B，通过有限元方法对比分析了两个换能器的固有频率和输出振幅，并进一步通过实验验证了设计理论与仿真分析的有效性。研究结果表明，在相同激励电压下，采用六端网络法设计得到的压电超声换能器B输出的超声振幅是换能器A输出振幅的1.5倍，六端网络法设计压电超声换能器可以提高所设计换能器的振动性能。      

Adjusting the geometry of implantable hearing aid components to human temporal bone. II: Microphone

Prerequisite to implantation of a piezoelectrical transducer of an implantable hearing aid is a shape allowing its implantation into human mastoid and middle ear. To approach this problem, a consecutive series of six transducer prototypes was created in an iterative process. Their functional geometry was evaluated in 50 human temporal bones. A shape for a functioning transducer was found which will enable implantation in 78% of the cases examined (confidence interval: 61.5%-89.2%). It will allow simultaneous implantation of the transducer into the mastoid and microphone, which is situated transmastoidal in the posterior wall of the ear canal. Furthermore, the transducer may be coupled to the ossicular chain or the perilymph.     

安川变频器G7在倾动炉车间的应用实践

安川变频器从原来的616G3、616G5到现在的616G7一直以其优越的力矩特性在提升设备中树立着良好的口碑,确立着领先的优势,在中国的变频器市场也占有重要的地位,在电梯、起重机等设备上被广泛运用。根据倾动炉车间多年对安川G7变频器的使用对其做些简单的介绍,并阐述其常见的故障。     

DNA repair in baboon alveolar macrophages: a system for assessing biohazardous materials

The influence of transducer position and angulation upon the mitral systolic echo was studied in 100 presumably healthy females. Echocardiographic studies were performed from the second, third, fourth and fifth intercostal spaces (ICS). The role of the sound beam's path relative to cardiac motion was assessed by analyzing the recorded mitral valve pattern as a function of transducer orientation, independent of the absolute ICS used. With the transducer directed caudally when both mitral leaflets and left atrium were recorded, holosystolic or midsystolic posterior motion of the mitral valve leaflet echo was seen in 59% of the subjects. These patterns, recorded this way, were not related to phonocardiographic signs suggesting mitral valve prolapse. Best correlation with phonocardiographic findings was obtained when the echocardiographic examination was performed with the transducer either perpendicular to the chest in the sagittal plane, or pointing slightly cephalad ('perpendicular' position). With the transducer in 'perpendicular' position, both holosystolic and midsystolic posterior motion of the mitral systolic echo, deviating more than 2 mm from a line joining the C and D points, were highly related statistically to phonocardiographic findings suggesting mitral valve prolapse. This study demonstrates that transducer position and angulation on the chest wall are important determinants of echocardiographic appearance of mitral valve during systole. Only the 'perpendicular' transducer position should be used when analyzing echocardiograms for the presence of mitral valve prolapse.     

Comparison of steady-state diffusion and transit time ultrasonic measurements of umbilical blood flow in the chronic fetal sheep preparation

OBJECTIVE: Our purpose was to measure umbilical blood flow continuously by use of a transit time ultrasonic flow transducer and to compare the blood flow measurements with the steady-state diffusion method in the chronic fetal sheep preparation. STUDY DESIGN: We compared umbilical blood flow measurements calculated by the steady-state diffusion method with ethanol as the diffusing substance and with the transit time ultrasonic flow transducer placed on the common umbilical artery in five chronically prepared fetal sheep. RESULTS: There was no statistical difference between measurements of umbilical blood flow measured by the flow transducer versus the steady-state diffusion method, 600 +/- 22 versus 664 +/- 56 ml per minute (mean +/- SEM) (p = 0.23). The mean coefficient of variation within each study was 13.6% for the steady-state diffusion method versus 4.1% for the transit time flow transducer. Umbilical blood flow variance was significantly lower as measured by the flow transducer compared with the diffusion method (p < 0.0001). There were no differences in umbilical blood flow per kilogram or fetal oxygen uptake between the two methods. CONCLUSION: We conclude that umbilical blood flow can be measured continuously under steady-state conditions by use of a transit time flow transducer. Because of the lower variability in the flow transducer-obtained measurements, we speculate that the flow transducer may differentiate alterations in umbilical blood flow with greater precision in chronic preparations. This may be advantageous for measuring absolute changes in fetal substrate uptake, especially under non-steady-state conditions.