Modification of X-ray Generator by Energy Reusing

X-ray is an important tool for charactering and analyzing materials. However, current X-ray generation is cost with low efficiency. For X-ray tube, which is mostly used in laboratories, only has an energy usage of 1% with all other energy dissipated into tremendous heats, and it needs continuous cool water flows to cool down the cathode. It generates X-ray by the bremsstrahlung of high energy electrons bombarding on the cathode target, the bremsstrahlung would contain X-ray with sufficiently high energy of the electrons. But most part of the electron energy becomes heats. In order to generate X-ray more cheaply with higher efficiency, methods about reusing the released heats during the working of the X-ray tube are brought up. Mimicking the photovoltaic effect, nonequilibrium carriers could also be injected via thermion emission when heating a metal, such injection is same to that of photonic injection which produces electromotive in a photovoltaic cell. In a photovoltaic cell the electron-hole pair generated by incident photons are nonequilibrium carriers that causes electromotive, while the thermion emission creates such electron-hole pairs via thermal excitation. Connecting metals suitable for thermion emission from the cathode into the p-n junction so that thermions as nonequilibrium carriers can be well injected into the p-n junction when the metals are heated by the cathode, with Thomson effect which enhances such injection, a thermal voltaic cell can be constructed and it can produce electricity only by heating the metals outside. Applying such thermal voltaic cell into current X-ray tube, it would produce electricity while absorbing the tremendous heats emerges when X-ray tube is working. Water flows are still used to control the temperature, but letting them boiling to keep the cathode at a temperature best for thermal voltaic cell, and the vapor may be used to drive a mini thermal power plant. In this way, the energy usage could be modified to a higher proportion. Stepwise up-conversion is possible to generate X-ray more cheaply but there are no suitable materials so far.     

SG420 t/h锅炉水冷壁高温腐蚀分析

贵溪电厂有４台ＳＧ４２０ｔ／ｈ型煤粉炉,其中３台炉的水冷壁发生了高温腐蚀。通过宏观,金相显微镜、能谱分析、Ｘ射线衍射检测分析以及化学实验等方法,得出了管壁减薄是发生了严重的硫化物型腐蚀的结论,并分析了腐蚀原因。     

Safe control [X-ray tubes]

Most X-ray tubes in scientific and industrial applications use filaments that are floating at a high voltage, typically 50 kV to 160 kV, from ground. The beam current taken by the X-ray tube, and hence the quantity of X-rays produced, is a function of the temperature of the filament; the hotter the filament the greater the beam current and the more X-rays. Also, the filament must run at a very high temperature before any emission is produced, so careful control of power in the filament is essential. This article looks at how the latest filament control circuits protect X-ray tubes.     

某电厂高压加热器换热管开裂泄漏原因分析

某电厂高压加热器（高加）换热管开裂泄漏,影响发电机组安全生产。通过宏观形貌分析、断口观察、腐蚀产物能谱分析和金相观察等方法,对高加换热管裂纹原因进行分析。研究结果表明：管口径向裂纹由应力腐蚀引起,管板附近换热管的环向裂纹由腐蚀疲劳和应力腐蚀共同引起,而导致腐蚀的主要原因是由于凝汽器泄漏使给水中氯离子超标及疏水侧空气的漏入。对此,提出了防范措施。     

医用X射线球管阳极靶运行状态的估计

医用X射线机球管是价格昂贵、寿命又较短的消耗件。球管内部基本都是使用单相电机来驱动阳极靶面旋转,避免过热而损坏。密封在球管内的单相电机没有速度传感器,因而无法得到转速的实际值,不利于保护。因此提出的根据单相异步电动机控制原理,采用基-2快速傅里叶变换(FFT)按时间抽取算法,对电机定子电流信号进行时域频域转换,利用转换结果进行功率谱分析来估计电机所驱动的阳极靶面的转速,防止因阳极靶面转速异常所带来的各种危害。仿真结果证明了该方法可以取得好的效果。目前,方案已经在X射线机产品中正式使用。     

Filter optimization for X-ray inspection of surface-mounted ICs

A thin Zn filter (/spl sim/300 /spl mu/m) and relatively low X-ray tube voltage (/spl sim/45 kV) is recommended for X-ray inspection of surface-mounted device solder joints on printed wiring boards (PWBs). An optimal filter minimizes the Si dose that could result in cumulative damage to sensitive integrated circuit (IC) nodes, yet provides good contrast for metals such as Cu traces on PWBs and device solder balls. While we expect orders of magnitude Si dose reductions when effective filters are inserted, a properly chosen filter should not attenuate the portion of the white X-ray spectrum required to image Cu, Sn, and Pb (solder balls). Some X-ray inspection suppliers can achieve a Si dose of as little as 0.060 rads, while other X-ray inspection suppliers, not yet optimized for minimum dose, may use as much as four orders of magnitude more dose. We used thermo luminescent detectors (TLDs) to measure the X-ray dose that IC product shipments would encounter during a shipping process, for example, as personal baggage or cargo, as /spl les/0.050 rads.     

弹丸初速测量系统X射线管高压电源的研究

针对弹丸测速系统X射线管在外场220 V市电下使用的问题,基于直流可调开关电源、全控元件IGBT、IR2130驱动器等硬件,依托ARM控制技术、电压逆变调节技术、PWM占空比脉宽调节技术以及PID闭环调节技术,实现了通过C#上位机界面监控和发送命令对外场弹丸测速系统X射线管的直流高压电源和灯丝电源的实时精确控制.在研究中,先对部分关键电路做了硬件模拟实验,验证了电路功能的可靠性.搭建整个硬件系统以及STM32软件控制架构,结合上位机来实现实时监测和人机交互功能.应用表明,系统工作较为稳定,实时性好,能够满足设计需求,能够有效支撑弹丸实速测量系统的相关测试.     

基于虚拟仪器技术的工频X线机单元电路实验系统的设计

为了提高工频X线机电路实验教学的开放性和解决实验设备费用高、易损坏、更新慢等问题,研究并开发一套教学使用的工频X线机单元电路实验仿真系统,可以完成工频X线机电路实验课程的基本教学任务。结合工频X线机电路实验教学课程的需求,以工频X线机典型的单元电路为例,采用电路仿真软件Multisim仿真实验电路,虚拟仪器开发软件LabVIEW进行实验系统界面设计,并利用接口技术实现二者之间的通信联结,完成工频X线机单元电路实验系统的构建。设计完成后的实验系统能够仿真实际X线机单元电路的工作过程,学生可以在理论学习的基础上,利用此套系统进行X线机整流电路、限时电路、空间电荷补偿电路、容量保护电路、旋转阳极启动、延时及保护电路的实验。测试结果表明,该实验系统可以完成工频X线机单元电路实验课程中的电路参数测量、电路信号测试及参数显示任务,通过与真实单元电路实验箱的对比,证明了实验结果可以反映出真实的X线机球管电气特性。该实验系统有效地增加了学生的动手实践机会,可扩展性强,有利于探究性电路实验的进行,因此,将虚拟仪器技术用于设计和实现工频X线机单元电路实验系统是一种非常有效的方式,既解决了实验设备不足的问题,也为其他医学影像设备电路实验仪器的设计和研制提供新的思路。     

12X18H12T钢管蒸汽侧氧化皮及其剥落物的微观结构与形貌特征

通过对某电厂12X18H12T过热器和再热器割管样品内壁氧化皮及其剥落物进行金相检验、扫描电镜观察、微区能谱分析、X-射线衍射等试验分析,研究和总结了18-8系列粗晶奥氏体不锈钢过热器和再热器蒸汽侧氧化皮的宏观和微观结构与形貌特征。研究结果表明：该不锈钢原生氧化皮通常可分为内、中、外3层氧化物,其内层为结构致密的富铬尖晶石结构氧化物,中间层主要是结构疏松、多孔的Fe3O4,最外层为结构致密但厚度较薄的Fe2O3;剥落物主要是原生氧化皮的外两层铁氧化物,内层氧化物一般并不剥落。原生氧化皮外层剥落部位在后继运行过程中不会再生长出新的Fe3O4类氧化物,但会逐渐生长出新的Fe2O3层,该次生Fe2O3层生长速度十分缓慢。     

18-8型奥氏体不锈钢锅炉管服役特性研究(三)

采用光学显微镜、透射电镜和X射线衍射仪等对不同服役时间的稳定化不锈钢锅炉管样品的微观组织进行了试验研究。结果表明,稳定化不锈钢锅炉管微观组织在服役过程中随着服役时间的延长,滑移线、孪晶和层错逐渐消失,位错密度逐渐降低、位错线趋于变直;晶内第二相数量略增多后基本不变、颗粒尺寸略增大,晶界第二相数量逐渐增多、尺寸逐渐增大。与非稳定化不锈钢锅炉管微观组织演变规律相比,其最大区别是晶内碳化物的变化和析出相成分比例不同。     

Robotics-an efficient tool for laboratory automation

As part of a major upgrading of the Dyckerhoff AG, Amoneburg cement plant, Germany, a fully automated quality control and quality assurance system has been installed. The laboratory automation system is the robotics-based QCX/Robolab system. At the production laboratory, samples from nine automatic sampling points are brought by a pneumatic tube transport system to the industrial robot and distributed to sample preparation and analytical equipment. The robot-controlled analysis activity comprises X-ray fluorescence, X-ray diffraction, particle size distribution, and color measurement. The results are used for automatic process control applications. A number of manually operated analytical devices are connected to the system, allowing automatic analysis-data collection for activities like quality test of incoming and outgoing products, environmental protection, etc. Via a network, all analytical and associated production data from the production control system are automatically transferred to the central plant data management system     

干式变压器绕组材质鉴别无损检测研究

本文中作者研究了铜、铝绕组的透照布置工艺,并对X射线吸收曲线及参数进行了分析,介绍了铜、铝绕组在不同管电压的剂量率衰减规律,建立了基于饱和电压-绕组厚度的铜、铝绕组鉴别方法。     

陶瓷金卤灯电弧管内壁腐蚀综述

本文分析了陶瓷金卤灯工作过程中,陶瓷管内壁的气相腐蚀机理及电弧管中的输运过程.介绍了诊断管壁腐蚀程度的X光成像、扫描电镜和努森泄流质谱等方法,从电弧管结构、金属卤化物组分改进和电极封接等方面总结了减少陶瓷管壁腐蚀的措施.     

G102钢高温过热器内壁氧化皮分析

初步探讨了锅炉给水加氧处理失当对受热面管材的影响。利用扫描电镜(SEM)及X射线衍射仪(XRD)对G102钢高温过热器管内产生的氧化皮进行分析。结果表明:高温过热器管内氧化皮为Fe3O4或Fe2O3结构,并呈多孔疏松状;脱落的氧化皮聚集在弯头处导致管壁过热,从而引发短时过热爆管。     

Three-Electrode Organic-Type G.M. Counter Design and Performance

The sensitivity of the organic-type G.M. tube is increased by introducing a third electrode (grid) between the cylindrical steel cathode and a concentric tungsten wire anode and applying positive potential to that grid. The optimum position of the grid inside the cathode corresponding to the minimum capacitance of the counter is determined by using the simulation technique. Plateau curves of this tube are obtained for different grid positions. It is justified that the best performance of the tube is determined with the optimum grid position. Plateau curves of the three-electrode G. M. tube are also reported, with optimum grid position, for different values of grid potential. It is found that the sensitivity of the counter can be controlled by variation of the grid potential.     

声波在锅炉换热器管阵列中的传播特性研究

基于对炉内单排和双排换热器管阵列声传播特性的研究基础,分析多排管阵列对声波的反射、透射和衍射机理;利用数学推理方法和迭代过程给出计算炉内多排管阵列声透射与反射系数的数学模型,研究多排换热器管阵列的声透射特性,揭示炉内多排管阵列的声反射与透射系数随声波频率、管排数和管阵列结构参数的变化关系;并在炉内实际温度下对声透射系数进行数值计算,为锅炉管道泄漏检测技术提供理论依据.     

核级热交换器管子管板胀接及质量控制

制造换热器管束时,管子管板的液压胀接是常用的加工工艺。在液压胀接过程中,主要经历了管子管壁屈服、管子管板间隙消失、加压到最大胀接力和卸压等过程,胀接质量主要受胀接力、间隙、清洁度和胀接长度等因素的影响。以CPR1000项目余热排出热交换器的胀接工艺为例,对管子管板液压胀接工艺评定和影响因素进行了分析,总结了胀接前及胀接过程中的质量控制要点,为核电换热器设备的质量控制提供参考。     

管道裂纹涡流检测线圈阻抗信号的快速仿真

使用放置式线圈对管道进行涡流检测,不同走向的裂纹可以获得相同的检测灵敏度。在对这类问题进行数值模拟时,由于线圈在无缺陷管壁中产生的场不存在解析解,难度很大。当管道半径远大于线圈尺寸时,管壁可看作平板导体,问题得到简化。如果管道半径不是远大于线圈尺寸,可以通过对平板模型的修正获得比较准确的数值仿真结果。     

超临界锅炉高温过热器爆管原因分析和解决对策

针对某电厂超临界锅炉高温过热器爆管的情况,通过爆口宏观分析、化学成分分析、金相分析以及爆口附近管段的力学性能测试,从该管段不同位置金相组织呈现的条状分布σ相,认定高温过热器长期超温。为此,对高温过热器进口集箱进行了内窥检查,发现异物堵塞节流管孔导致烟气侧和蒸汽侧温度出现严重偏差是造成超温爆管的根本原因,并提出了预防措施。     

SA210A1+INCONEL625复合管的弯制

介绍50.8×4.6INCONEL625+SA210A1复合管的变曲工艺试验研究情况。通过弯管模具的选配,复合管表面焊接处理,最终获得了该类复合管实际弯曲的合理方法,掌握了其弯曲性能。同时也介绍了该类复合管弯后的材料性能变化情况。图3表4