Implementation of multifilter based twin-prototypes for core electron temperature measurements in the TJ-II stellarator

The design and preliminary results from a prototype of a multifilter based electron temperature diagnostic for the TJ-II stellarator are presented. The diagnostic consists of four photodiodes with filters of different thicknesses to determine the electron temperature in a wide variety of plasma compositions, thanks to the set of six different signal-pairs ratios available. The impurity transport code IONEQ, the TJ-II soft x-ray tomography, and the VUV survey diagnostics give the necessary information to assess the proposed diagnostic reliability. In parallel, a vacuum-compatible multichannel electronic board has been designed for a future linear array to determine electron temperature profiles in high-density plasmas.     

应用聚焦离子束/电子束技术的碳纳米管探针制备工艺研究

提出利用电子束诱导铂沉积和聚焦离子束铣削技术,实现碳纳米管原子力显微镜探针针尖的制备和结构优化研究。结合高分辨率扫描电子显微镜观测和纳米操纵仪,利用电子束诱导铂沉积实现碳纳米管固定到普通原子力显微镜探针末端,可实现直径小于10nm的纳米管探针制备。提出基于聚焦离子束铣削和照射技术实现对纳米管针尖的长度、角度的精确调控优化,纳米管探针的角度调控精度优于1°。     

Optics of ion beams for the neutral beam injection system on HL-2A Tokamak

The ion beam optics for the neutral beam injection system on HL-2A Tokomak is studied by two- dimensional numerical simulation program firstly, where the emitting surface is taken at 100 Debye lengths from the plasma electrode. The mathematical formulation, computation techniques are described. Typical ion orbits, equipotential contours, and emittance diagram are shown. For a fixed geometry electrode, the effect of plasma density, plasma potential and plasma electron temperature on ion beam optics is examined, and the calculation reliability is confirmed by experimental results. In order to improve ion beam optics, the application of a small pre-acceleration voltage (～100 V) between the plasma electrode and the arc discharge anode is reasonable, and a lower plasma electron temperature is desired. The results allow optimization of the ion beam optics in the neutral beam injection system on HL-2A Tokomak and provide guidelines for designing future neutral beam injection system on HL-2M Tokomak.     

基于ANSYS的中性束注入器主真空室结构力学分析

利用ANSYS软件建立了EAST中性束注入器样机主真空室的有限元模型,分析了主真空室的受力情况;主真空室由三段组装而成,依据实际的材料和受力情况,分别对三段放置于地面以及整体连接放置在导轨上两种工作状况下进行结构静力学分析,得到了相应工作状况下的结构应力分布和变形情况。分析表明主真空室在两种工作状况下最大Von-Mises等效应力值小于材料屈服强度,主真空室结构是安全和稳定的,分析结果给主真空室下一步的优化设计和结构选材提供了依据。     

电子束辐照对GaN基蓝光LED特性参数影响

本文利用能量为1-3MeV、最大功率为90KW的工业用地那米型电子加速器产生的低能电子束对GaN基蓝光LED进行了电子束辐照实验,对比了辐照前后的LED颜色参数,光度参数的变化,同时对实验结果进行分析和讨论。结果表明,在电子束辐照下,LED的主波长发生了漂移,色纯度提高,光通量、光效都有所降低,并且发现电子束辐照会引起LED芯片量子阱中的原子位移,非复合型复合,降低少子寿命。     

湿式制动驱动桥壳环焊缝真空电子束焊接工艺研究

通过对湿式制动驱动桥壳材料的焊接性和焊接结构分析,研究了用真空电子束焊接湿式制动驱动桥壳本体与半轴套管的工艺方法,并对焊接过程中存在的主要问题、焊接接头的力学性能和显微组织进行了分析,确定其最佳工艺参数。结果表明,焊接接头的性能符合国家相关标准且焊后桥壳变形小,耐疲劳性能好,其使用性能完全满足湿式制动驱动桥壳的设计要求。     

Multiobjective optimization of injection molding parameters based on soft computing and variable complexity method

The objective of this study is to propose an intelligent methodology for efficiently optimizing the injection molding parameters when multiple constraints and multiple objectives are involved. Multiple objective functions reflecting the product quality, manufacturing cost and molding efficiency were constructed for the optimization model of injection molding parameters while multiple constraint functions reflecting the requirements of clients and the restrictions in the capacity of injection molding machines were established as well. A novel methodology integrating variable complexity methods (VCMs), constrained non-dominated sorted genetic algorithm (CNSGA), back propagation neural networks (BPNNs) and Moldflow analyses was put forward to locate the Pareto optimal solutions to the constrained multiobjective optimization problem. The VCMs enabled both the knowledge-based simplification of the optimization model and the variable-precision flow analyses of different injection molding parameter schemes. The Moldflow analyses were applied to collect the precise sample data for developing BPNNs and to fine-tune the Pareto-optimal solutions after the CNSGA-based optimization while the approximate BPNNs were utilized to efficiently compute the fitness of every individual during the evolution of CNSGA. The case study of optimizing the mold and process parameters for manufacturing mice with a compound-cavity mold demonstrated the feasibility and intelligence of proposed methodology.     

A magnetic analyzer of a helical electron beam based on a controlled magnetic mirror

A magnetic analyzer of a helical subrelativistic electron beam formed by a three-electrode magnetron-injector gun in the field of a cryomagnet is described. Electrons are separated in transverse velocities by a magnetic field adiabatically increasing along the beam direction. The analyzer was used to measure the electron spread in velocities and the pitch factor of a microsecond helical electron beam with an electron energy of 300 keV and a current of 100 A.     

Supersonic helium beam diagnostic for fluctuation measurements of electron temperature and density at the Tokamak TEXTOR

A supersonic helium beam diagnostic, based on the line-ratio technique for high resolution electron density and temperature measurements in the plasma edge (r/a > 0.9) was designed, built, and optimised at TEXTOR (Torus Experiment for Technology Oriented Research). The supersonic injection system, based on the Campargue skimmer-nozzle concept, was developed and optimised in order to provide both a high neutral helium beam density of n(0) = 1.5 × 10(18) m(-3) and a low beam divergence of ±1° simultaneously, achieving a poloidal resolution of Δ(poloidal) = 9 mm. The setup utilises a newly developed dead volume free piezo valve for operation in a high magnetic field environment of up to 2 T with a maximum repetition rate of 80 Hz. Gas injections are realised for a duration of 120 ms at a repetition rate of 2 Hz (duty cycle 1/3). In combination with a high sensitivity detection system, consisting of three 32 multi-channel photomultipliers (PMTs), measurements of edge electron temperature and density with a radial resolution of Δ(radial) = 2 mm and a maximum temporal resolution of Δt ? 2 μs (470 kHz) are possible for the first time. The diagnostic setup at TEXTOR is presented. The newly developed injection system and its theoretical bases are discussed. The applicability of the stationary collisional-radiative model as basis of the line-ratio technique is shown. Finally, an example of a fluctuation analysis demonstrating the unique high temporal and spatial resolution capabilities of this new diagnostic is presented.     

Design of the injection beamline for the Californium Rare Isotope Breeder Upgrade electron beam ion source charge breeder

The design of the ion injection line connecting the electron beam ion source (EBIS) charge breeder and the Californium Rare Isotope Breeder Upgrade radio frequency quadrupole cooler-buncher at the Argonne Tandem Linear Accelerator System was investigated with particle tracking simulations. The injection line was configured to accommodate several differential pumping sections, individual optical components were optimized to minimize emittance growth, and the ion beam parameters were matched with the EBIS electron beam acceptance to minimize losses upon injection.     

Applied technique of focused ion beam milling based on microstructure of photonic bandgap fiber

In this paper, a precision micromachining technique for photonic bandgap fiber (PBGF) using focused ion beam (FIB) milling was reported. Types of PBGF have the honeycomb structure with a hollow core surrounded by microstructured cladding, and the widths of the thin silica struts are only 10～100 nm. The shape of fiber section is the most important prerequisite for maintaining good output coupling efficiency and allowing gas diffusion. Therefore, a proper machining method can avoid microstructure collapse and is crucially important for the experimental investigations. The FIB milling process was discussed and realized to improve performance of PBGF gas cell in this study. The absorption spectra of acetylene (C₂H₂) gas and methane (CH₄) gas have been investigated using the propose measurement system based on PBGF gas cell. The experimental results clearly indicated a high overlap between the propagating light and filled gas inside the PBGF. Therefore, these studies can contribute to highly sensitive gas sensing, higher accurate wavelength references, and other applications.     

Probing the local temperature by in situ electron microscopy on a heated Si3N4 membrane

We present a method allowing us to obtain localized heating that is compatible with high-temperature operation and real time scanning and transmission electron microscopy. Localized heating is induced by flowing current through tungsten nanowires deposited by focused ion-beam-induced deposition on a 50-nm-thick Si₃N₄ membrane. Based on the heat transport between the nanowire and the substrate, we applied an analytical model to obtain the temperature profile as a function of electrical power. In this model, the key parameter is the thermal resistance between the nanowire and the substrate that we determined experimentally by measuring electrical power and local temperature. The local temperature is measured by observing the evaporation of gold nanoparticle by electron microscopy. These in situ heating and temperature-probing capabilities are used to study the crystallization of the Si₃N₄ membrane and the growth of silicon nanowires.     

Research on temperature control module of injection molding machine based on C8051F020

The design of a measurement and control system of injection molding machine based on C8051F020 SCM is presented in this paper. Some resources are provided by C8051F020 such as ADC, DAC, inner temperature sensors and PWM functions. The application and achievement of the improved PID algorithm in constant temperature control of charging barrel for the injection molding machine are introduced in the paper. Given that the temperature of the charging barrel can be monitored in real-time and the corresponding temperature response curve can be acquired, the PID parameters can be adjusted conveniently and rapidly during the experiments of the temperature control.     

Study of beam width on reconstructed image contrast using the first generation gamma ray CT

Different factors may influence the image quality of the first generation computed tomography (CT) system single-source-single-detector. One of the factors in the improvement of the reconstructed image quality is the related characteristics of the beam width. These characteristics depend on the shape of collimator and dimension of collimation apertures. For studying the effect of beam width an industrial CT system was designed and developed. The CT scanner consists of a 5.08 cm NaI(Tl) detector in diameter and a ¹³⁷Cs (30 mCi) radioactive source. The position of phantom was defined by three motors. The CT scans were taken out by scanning 180° to collect attenuation beams. The images are reconstructed from the measured projections by the filtered back projection method to perform the inverse Radon transform. In this study we have investigated the beam width on reconstructed image contrast. To go through the process, several experiments were performed with different collimation apertures. Finally, the contrast of different images is compared by computing the RMS contrast of each image.     

The effect of the electron beam on various mounting and coating media in scanning electron microscopy

Eight commonly used specimen adhesives were examined under the ‘Stereo-scan’ scanning electron microscope to determine the effects of the electron beam on their surface topography. The adhesives were initially examined uncoated, and then coated variously with carbon, and seven different metals and alloys. The effect of the beam on the coated and uncoated adhesives was recorded. The results are presented in tabular form. The purpose of the experiments was to determine the extent of the damage, if any, produced by the beam, on the adhesive, and to try to discover the most damage-resistant combinations. While combinations are damage-free, some of the more easily damaged adhesives are regarded as being suitable for certain specialized purposes, where their special properties over-ride their susceptibility to beam damage.     

基于SiPM的阵列式X射线背散探测器设计

阵列式探测器是背散射成像设备能够小型化的关键。受限于光电转换器件的灵敏度和转换效率等因素,阵列式探测器设计一直进展缓慢。本文提出使用硅光电倍增管(SiPM)作为核心部件,并从准直器、闪烁晶体和光电转换元件进行阵列背散射探测器设计的新思路。利用X射线特征谱线建立仿真模型,确定闪烁体CSI厚度为1 mm;准直器设计为栅格状,栅格高度4 cm,间隔为6 mm;SiPM尺寸相应为6 mm×6 mm。根据设计结果完成了探测器单个组件的加工,通过实际实验验证设计结果,实验证明合理设计的SiPM可以满足本应用长时、低光照强度以及被探测物体的厚度变化范围较大的要求。     

基于DS18820与AVR单片机的测温技术

文中介绍了单总线数字式温度传感器DS18820的应用特点。给出了基于DS18820与AVR单片机CVAVR编译器的编程思路以及多点测温的程序设计。分析并提出了测温系统数据不稳定的电路改进措施。同时给出了接口程序的编程技巧和应用实例。     

An experimental study on spray and combustion characteristics based on fuel temperature of direct injection bio-ethanol-gasoline blending fuel

This study investigated the spray and combustion characteristics of a direct injection spark ignition type system based on the changes in the temperature of the blended fuel (with bio-ethanol and gasoline). The test was performed in a chamber with a constant volume. The diameter and width of the chamber were 86 mm and 39 mm, respectively. The bio-ethanol test fuel was blended at volume ratios of 0 %, 10 %, 20 % and 100 %. The temperature of the fuel was set as −7, 25 and 35 °C. The fuel injection pressure and ambient pressure were set as 4.5 and 0.5 MPa, respectively. The shape and characteristics of the spray were investigated through a spray experiment. The increase in the fuel temperature changed its density and viscosity; this in turn increased spray penetration and spray area and increased the bio-ethanol blending ratio. The combustion visualization and experimental analysis indicated that the decrease in the fuel temperature and the increase in the bio-ethanol blending ratio led to the high viscosity and low heating value. This resulted in an increase in the ignition delay and a decrease in the rate of heat release. It is necessary to adjust the spray strategy and ignition timing to adopt bio-ethanol blended fuel as an alternative fuel.

     

基于ANSYS的龙门式直角坐标机器人横梁分析

对龙门式直角坐标机器人的核心部件-Y轴横梁进行了有限元计算和分析.首先对直角坐标机器人的Y轴横梁进行建模,利用ANSYS软件分析计算出横梁的变形分布情况,然后对其分布规律做简要的分析,为后续的横梁结构优化设计提供理论依据.