Numerical studies for plasmas of a linear plasma device HIT-PSI with geometry modified SOLPS-ITER

The HIT-PSI is a linear plasma device built for physically simulating the high heat flux environment of future reactor divertors to test/develop advanced target plate materials.In this study,the geometry-modified SOLPS-ITER program is employed to examine the effects of the magnetic field strength and neutral pressure in the device on the heat flux experienced by the target plate of the HIT-PSI device.The findings of the numerical simulation indicate a positive correlation between the magnetic field strength and the heat flux density.Conversely,there is a negative correlation observed between the heat flux density and the neutral pressure.When the magnetic field strength at the axis exceeds 1 tesla and the neutral pressure falls below 10 Pa,the HIT-PSI has the capability to attain a heat flux of 10 MW·m-2 at the target plate.The simulation results offer a valuable point of reference for subsequent experiments at HIT-PSI.

Analysis of displacement damage effects on the charge-coupled device induced by neutrons at Back-n in the China Spallation Neutron Source

Displacement damage effects on the charge-coupled device(CCD)induced by neutrons at the back-streaming white neutron source(Back-n)in the China Spallation Neutron Source(CSNS)are analyzed according to an online irradiation experiment.The hot pixels,random telegraph signal(RTS),mean dark signal,dark current and dark signal non-uniformity(DSNU)induced by Back-n are presented.The dark current is calculated according to the mean dark signal at various integration times.The single-particle displacement damage and transient response are also observed based on the online measurement data.The trends of hot pixels,mean dark signal,DSNU and RTS degradation are related to the integration time and irradiation fluence.The mean dark signal,dark current and DSNU2 are nearly linear with neutron irradiation fluence when nearly all the pixels do not reach saturation.In addition,the mechanisms of the displacement damage effects on the CCD are demonstrated by combining the experimental results and technology computer-aided design(TCAD)simulation.Radiation-induced traps in the space charge region of the CCD will act as generation/recombination centers of electron-hole pairs,leading to an increase in the dark signal.

Investigating the Thermal Stress of Millisecond Pulsed Laser Irradiation on Charge-Coupled Devices

In this study, a two-dimensional model describing thermal stress on a charge-coupled device (CCD) induced by ms laser pulses was examined. Considering the nonlinearity of the CCD’s material parameters and the melting phase transition process of aluminum electrode materials was considered by using equivalent specific heat capacity method, the physical process where a laser pulse irradiating a CCD pixel array was simulated using COMSOL Multiphysics software. The temperature field and thermal stress field were calculated and analyzed. In order to clarify the mechanism producing damage on the CCD detector, Raman spectra from silicon were measured with a micro-Raman spectrometer to determine stress change in the CCD chip. The procedure presented herein illustrates a method for evaluating strain in a CCD after laser irradiation.

Detailed characterization of polycapillary focusing x-ray lenses by a charge-coupled device detector and a pinhole

A method to measure the detailed performance of polycapillary x-ray optics by a pinhole and charge coupled device(CCD)detector was proposed in this study.The pinhole was located between the x-ray source and the polycapillary x-ray optics to determine the illuminating region of the incident x-ray beam on the input side of the optics.The CCD detector placed downstream of the polycapillary x-ray optics ensured that the incident x-ray beam controlled by the pinhole irradiated a specific region of the input surface of the optics.The intensity of the output beam of the polycapillary x-ray optics was obtained from the far-field image of the output beam of the optics captured by CCD detector.As an application example,the focal spot size,gain in power density,transmission efficiency,and beam divergence of different parts of a polycapillary focusing x-ray lenses(PFXRL)were measured by a pinhole and CCD detector.Three pinholes with diameters of 500,1000,and 2000μm were used to adjust the diameter of the incident x-ray beam illuminating the PFXRL from 500μm to the entire surface of the input side of the PFXRL.The focal spot size of the PFXRL,gain in power density,transmission efficiency,and beam divergence ranged from 27.1μm to 34.6μm,400 to 3460,26.70%to 5.38%,and 16.8 mrad to 84.86 mrad,respectively.

Electron Magnetohydrodynamics Magnetic Reconnection Experiment on Keda Linear Magnetized Plasma Device

We conduct an electron magnetohydrodynamics magnetic reconnection experiment with guide-field in our Keda linear magnetized plasma device, in which two pulsed currents with the same direction are conducted in parallel with the axial direction of the main chamber of the device using two long aluminum sticks. After approximately 5μs, an X-type magnetic field line topology is formed at the center of the chamber. With the formation of the X-type topology of magnetic field lines, we can also find the rapid increase of the current and ratio of the common flux to the private flux in this area. Additionally, a reduction in the plasma density and the plasma density concentration along one pair of separatrices can also be found.

AN ALGORITHM FOR CANONICAL PIECEWISE-LINEAR DYNAMIC NETWORKS CONTAINING DEVICES WITH CHARACTERISTIC FAMILY

This paper improves the modeling method for the device with characteristic family presented by L. O. Chua (1977) and results in the one-dimensional fluctuating canonical piecewise-linear model. It is an efficient model. The algorithm for canonical piecewise-linear dynamic networks with one dimensional fluctuating model is discussed in detail.

Particle flux characteristics of a compact high-field cascaded arc plasma device

A new compact cascaded arc device for plasma-wall interaction study is developed at the Institute of Plasma Physics,Chinese Academy of Sciences.A magnetic field up to 0.8 T is achieved to confine plasmas in a 1.2 m long and 0.1 m diameter vacuum chamber.Gas fluid type analysis in this compact vacuum system was done under high particle flux condition.The gas pressure obtained by calculation was consistent with the measurement result.Continuous argon plasma discharge with ion flux of~0.5×10^(24)m^(-2)s^(-1)is successfully sustained for more than 1h.The effects of magnetic field configuration,gas flow rate,and discharge arc current on the ion flux to target were studied in detail.

Development of Flexible Spherical Actuator with 3D Coordinate Measuring Device

Rehabilitation devices help to recover the physical abilities of patients. This study aims to develop a portable rehabilitation device that is safe to use when?patients are holding it by hands. In a previous study, to realize a home rehabilitation device, a flexible spherical actuator that can provide motion to patients was developed. In this study, to measure the relative position between both handling stages, a 3D coordinate measuring device using three wire-type linear potentiometers and an embedded controller was proposed and tested. In this paper, the spherical actuator with built-in 3D coordinate measuring device is described. The measuring method and experimental results obtained are also presented. The tracking position control of the actuator using the measuring device was carried out. As a result, the position of the handling stages can be successfully controlled using the feedback signal from the tested?measuring device.

Effects of insertion device on SSRF storage ring

Shanghai Synchrotron Radiation Facility (SSRF), one of the third generation light sources, aims to pro-duce high brightness and/or high flux X-ray source for users; therefore insertion devices (IDs) are important magnetic elements for SSRF. In this paper, the linear perturbations due to IDs toward its storage ring lattice, such as beta func-tion distortions, tune shifts, emittance growths, and energy spreads are estimated by using analytical formulae, and the nonlinear effects from IDs, especially dynamic aperture, are simulated by using Racetrack code. The results show that (a) the reduction of dynamic aperture from single undulator is negligible, since electron beam energy of 3.5 GeV is high and ID’s magnetic field is low, and the beta functions in the middle of straight sections, where ID is located, are well optimized; (b) however, the reduction from single wigglers, especially super-conducting wiggler, is visible, be-cause of its higher magnetic field; (c) effects of each ID on emittance growths and energy spreads are less than 7%.

SOLVERS FOR SYSTEMS OF LARGE SPARSE LINEAR AND NONLINEAR EQUATIONS BASED ON MULTI-GPUS

Numerical treatment of engineering application problems often eventually results in a solution of systems of linear or nonlinear equations.The solution process using digital computational devices usually takes tremendous time due to the extremely large size encountered in most real-world engineering applications.So,practical solvers for systems of linear and nonlinear equations based on multi graphic process units（GPUs）are proposed in order to accelerate the solving process.In the linear and nonlinear solvers,the preconditioned bi-conjugate gradient stable（PBi-CGstab）method and the Inexact Newton method are used to achieve the fast and stable convergence behavior.Multi-GPUs are utilized to obtain more data storage that large size problems need.

基于局域发射光谱的LEAD装置螺旋波等离子参数测量

发射光谱法是常见的用于诊断等离子体的光学诊断技术,然而,这项技术并不能在空间上分辨等离子体。为了以低成本得到高空间分辨率的等离子体参数,发展了局域发射光谱法。这是一种将光纤伸入等离子体中以采集光纤前端等离子体光谱学信息的高空间分辨率光学诊断技术。介绍了局域发射光谱法技术的原理,并在大型线性等离子体实验装置LEAD上用蚊香形射频天线激发了氩等离子体,并在不同的射频功率和径向位置下对比了局域发射光谱法测得的等离子体光强和朗缪尔探针测得的等离子体电子密度,同时观察到了在射频功率500 W左右等离子体从感性耦合放电模式到螺旋波模式的跳变。结果表明:局域发射光谱法测得的光强与实验室现有的朗缪尔探针测量的电子密度之间较强的正相关,证明了用光强表征电子密度的可靠性,和LEAD装置上现有的朗缪尔探针在不同的等离子体模式的诊断上互补。

Metal-Halide Perovskite Submicrometer-Thick Films for Ultra-Stable Self-Powered Direct X-Ray Detectors

Metal-halide perovskites are revolutionizing the world of X-ray detectors,due to the development of sensitive,fast,and cost-effective devices.Self-powered operation,ensuring portability and low power consumption,has also been recently demonstrated in both bulk materials and thin films.However,the signal stability and repeatability under continuous X-ray exposure has only been tested up to a few hours,often reporting degradation of the detection performance.Here it is shown that self-powered direct X-ray detectors,fabricated starting from a FAPbBr_(3)submicrometer-thick film deposition onto a mesoporous TiO_(2)scaffold,can withstand a 26-day uninterrupted X-ray exposure with negligible signal loss,demonstrating ultra-high operational stability and excellent repeatability.No structural modification is observed after irradiation with a total ionizing dose of almost 200 Gy,revealing an unexpectedly high radiation hardness for a metal-halide perovskite thin film.In addition,trap-assisted photoconductive gain enabled the device to achieve a record bulk sensitivity of 7.28 C Gy^(−1)cm^(−3)at 0 V,an unprecedented value in the field of thin-film-based photoconductors and photodiodes for“hard”X-rays.Finally,prototypal validation under the X-ray beam produced by a medical linear accelerator for cancer treatment is also introduced.

应用于高速图像传感器的高线性度Latch ADC

针对高速应用设备对CMOS图像传感器高速、高线性度的要求,本文在传统SS ADC(Single Slope ADC,单斜模数转换器)的基础上,实现了一款应用于图像传感器的Latch ADC,工作频率达到了600 MHz。Latch ADC可以多列像素共用一个Gray Code计数器,并通过Latch结构快速锁定和存储数据,实现了SS ADC中Counter和SRAM的功能。本文采用110 nm工艺,实现了一种高速12位Latch ADC。经过仿真验证,本文的Latch ADC具有高线性度,每次转换的周期为7.094μs,平均功率为180.3μW,转换功耗为1.279 nJ.

基于位置敏感器件的杨氏模量测量

利用位置敏感器件将经典的拉伸法测杨氏模量中金属丝的微小伸长量转换成电压信号变化,再由放大电路放大后,经过数据采集卡接入计算机进行实时数据采集,实现了杨氏模量的数字化测量。实验运用了现代科技测量的新器件、新技术,将硬件和软件在传统物理实验上进行了融合,实验数据处理设计了代表性的最小二乘法线性拟合和逐差法进行处理,测量结果可靠,可作为一个典型的综合性物理实验进行教学推广和使用。

便携式继电保护设备多源信息运检装置研究

目前,发电厂保护定值核对工作都是采用人工核对的方式,核对流程为先通过针孔打印机打印继电保护装置内的定值单,再人工比对打印的定值单与计划定值单,其工作量大,且易误判与漏判。针对人工核对方式存在的问题,本文研制出一种便携式继电保护设备多源信息运检装置,其可以通过继保装置的打印口获得定值单数据,实现虚拟定值打印功能。并设计了两种核对模式比对保存的设备定值单与计划定值单,第一种为通过比较泛型表达式的值进行自动核对定值,实现继保装置中当前整定值与便携式装置内预设值的比较;第二种为图像比对的方式,利用PDF文件线性识别字符法(LDA)对文本进行分类,接着使用余弦异同度对比字符是否完全相同,实现调度下发的定值单电子档与保护装置的虚拟打印定值单的准确比较。应用效果表明,本装置能够显著提升发电厂继电保护定值核对的效率和准确性。

基于线性控制的变电站出线故障处置策略

变电站出线接地故障会导致用户侧负荷受损,对电力系统稳定性产生负面影响。因此及时判别故障线路,消除接地故障对维持系统的稳定十分重要。部分地区以小电流接地选线装置来进行故障线路判别,但其准确度受多方面因素影响,通过对某县电网故障数据样本统计分析,梳理接地故障产生的原因、变电站小电流接地选线装置的选线原理和失准的原因,提出基于线性控制的变电站出线故障处置策略模型,为后续变电站出线接地故障预防处理,提高电压稳定水平提供参考。

新一代多表位三相直接式电能表检验装置研制

由于传统的三相直接式电能表检定装置逐渐不能满足R46国际标准的检定工作需求,设计一种符合R46国际标准的新一代多表位三相直接式电能表检验装置,该装置主要由信号源、线性功率放大器、三相标准电能表、误差计算器、穿心隔离式电流互感器、蓝牙通信转换器等组成。可以对2013版智能电能表、2020版智能电能表以及智能物联电能表进行兼容测试,完成基本误差、潜起动、电能表常数、电能表示值误差、计时准确度等常规测试项目,同时还能满足谐波电能准确度、谐波测量准确度等R46国际标准新增测试项目的要求。测试结果表明,该装置在同时检测32只直接式电能表时,可以稳定可靠地工作,技术指标满足设计要求。

超声探伤仪垂直线性不确定度研究

以研究超声探伤仪垂直线性不确定度为目的。先介绍围绕具体的仪器型号及技术参数,具体分析超声探伤仪垂直线性不确定度评定依据及方法,并以建模方式进行不确定度评定,最后出具垂直线性不确定度报告,提出超声探伤仪检定装置校准的要点。旨在为超声探测人员提供借鉴,掌握超声探伤仪垂直线性不确定度的探究技巧,真正优化超声探伤仪的质量与性能,真正发挥其功能作用。

永磁同步直线电动机动子清洁装置的设计

针对永磁同步直线电动机在矿山运输系统中动子吸附铁屑和磁性尘沙的问题,现提出了一种可以安装在定子上的清洁装置,通过设计清扫吸附装置的结构,应用有限元仿真软件计算动子吸附铁屑和磁性尘沙的受力情况,使用流体仿真软件计算清洁装置清除动子表面铁屑和磁性尘沙所需的风量和风速。通过清洁装置的样机试验表明,清洁装置具有良好的清扫和吸附铁屑、灰尘的能力,达到永磁同步电动机永磁体动子表面清洁的效果。

A Synchronous and Deterministic MAC Protocol for Wireless Communications on Linear Topologies

Linear topology is useful in several pervasive application scenarios. Even though a linear topology can be handled by unspecific routing algorithms over general purpose MAC protocols, better performance can be obtained by specialized techniques. This paper describes a new communication scheme called Wireless Wire (WiWi), which builds up a bidirectional wireless communication channel with deterministic properties in terms of throughput and latency over a strip of pervasive devices with short-range transmission capabilities. The system is synchronous and fault tolerant. With low cost and extremely simple devices, WiWi builds up a “wire-like” dielectric link, but its applications are not limited to end-to-end communications. For example, WiWi can be used to collect data from sensors along the path, thus acting as a virtual conveyor belt.