CU纳米线的高温原位加热XRD研究

采用电化学沉积方法,在孔径约50 nm的阳极氧化铝模板中生长Cu纳米线,经过高温原位加热XRD实验,证实了其热膨胀系数约2.6×10-5 K-1,稍大于块体Cu,与文献中Cu纳米线近似为零的热膨胀系数有明显的区别.对这一现象进行了简要的讨论后得出结论认为:基于模板生长的Cu纳米线,其晶格完整程度是决定热膨胀的重要因素.     

BEPCII电子日志系统

由于北京正负电子对撞机重大改造工程(BEPCII)建设和未来运行的要求,需要提供一个开放的电子日志平台,供BEPCII开发和运行人员进行日志录入并通过网页访问电子日志系统,摆脱传统的书面形式的日志,给大家提供一个公开透明的日志平台.本电子日志系统以德国DESY的电子日志系统为模板研制而成.用了目前比较成熟的JSP技术来生成动态Web应用.本文将介绍BEPCII电子日志系统的研发背景和过程.     

Theoretical research on the transport and ionization rate coefficients in glow discharge dusty plasma

The electron kinetic model for investigating the transport and ionization rate coefficients of argon glow discharge dusty plasma is developed from the Boltzmann equation.Both of the electron-neutral and electron-dust collisions are considered as collision terms in the kinetic equation.The kinetic equation is simplified by employing the local approximation and nonlocal approach under the same discharge conditions,and the corresponding simplified kinetic equations are known as local and nonlocal kinetic equations respectively.Then the electron energy distribution function(EEDF)is obtained by numerically solving the local and nonlocal kinetic equations and the dust charging equations simultaneously.Based on the obtained EEDFs,the effective electron temperature,electron mobility,electron diffusion coefficient and ionization rate coefficient are calculated for different discharge conditions.It is shown that the EEDFs calculated from the local kinetic model clearly differ from the nonlocal EEDFs and both the local and nonlocal EEDFs are also clearly different with Maxwellian distributions.The appearance of dust particles results in an obvious decrease of high energy electrons and increase of low energy electrons when axial electric field is low.With the increase of axial electric field,the influence of dust particles on the EEDFs becomes smaller.The electron mobility and diffusion coefficients calculated on the basis of local and nonlocal EEDFs do not differ greatly to the dust-free ones.While,when dust density nd=10^6 cm^?3,the electron mobility increases obviously compared with the dust-free results at low axial electric field and decreases with the increasing axial electric field until they are close to the dust-free ones.Meanwhile,electron diffusion coefficients for dusty case become smaller and decrease with the increasing axial electric field.The ionization rate coefficients decrease when dust particles are introduced and they approach the dust-free results gradually with the increasing axial electric field.     

“第一届中国(国际)核电仪控技术大会”征文通知

各有关单位:随着我国核电的快速发展,对满足核电需求的仪控技术与装置的研究、设计、制造、选型、应用、维护以及国产化水平都提出了越来越高的要求。为了更好地推动我国核电仪控技术的发展,促进产学研用的紧密结合,同时促进我国核电学术界的国际交流,中国核学会与中国仪器仪表学会共同研究决定联合举办第一届中国(国际)核电仪控技术大会。     

Analysis of the characteristics of the plasma of an RF driven ion source for a neutral beam injector

A radio frequency(RF)driven ion source is a very important component of a neutral beam injector for large magnetic confinement fusion devices.In order to study the key technology and physics of an RF driven ion source for a neutral beam injector in China,an RF ion source test facility was developed at the Institute of Plasma Physics,Chinese Academy of Sciences.In this paper,a two-dimensional fluid model is used to simulate the fundamental physical characteristics of RF plasma discharge.Simulation results show the relationship of the characteristics of plasma(such as electron density and electron temperature)and RF power and gas pressure.In order to verify the effectiveness of the model,the characteristics of the plasma are investigated using a Langmuir probe.In this paper,experimental and simulation results are presented,and the possible reasons for the discrepancies between them are given.This paper can help us understand the characteristics of RF plasma discharge,and give a basis for further R&D for an RF ion source.     

真丝绸的低压汞灯光引发接枝共聚研究

本工作用低压汞灯作为光源,以丙烯酸羟丙酯(2-Hydroxypropyl acrylate,HPA)为单体,对真丝绸的紫外光光化学接技改性进行了系统研究,反应体系中无任何引发剂或者光敏剂.用衰减全反射红外光谱(Attenuated total reflectance infrared spectroscopy,ATR-IR)、差示扫描量热法(Differential scanning calo-danetry,DSC)和热重分析(Thermal gravity analysis,TGA)等对光接枝产物进行了表征.探索了光照反应时间、单体浓度、pH值、多官能团单体的存在对接枝率的影响规律.研究表明,此方法可获得较高的接枝率,且低压汞灯具有无污染、设备简便价格低廉、寿命长,易于操作等优点,是一种有效的真丝绸改性方法.     

纪念王淦昌先生诞辰100周年

2007年5月28日,是我国杰出的核物理学家、中国核学会第一任理事长王淦昌先生诞辰100周年纪念日.中国核学会与相关单位一起举办了一系列活动,缅怀先辈,激励后人. 王淦昌先生是我国杰出的核物理学家、中国科学院资深院士、"两弹一星"功勋奖章获得者、中国实验原子核物理和宇宙射线及粒子物理研究的奠基人.     

Optimization of the Water-Cooled Structure for the Divertor Plates in EAST Based on an Orthogonal Theory

An orthogonal experimental scheme was designed for optimizing a water-cooled structure of the divertor plate.There were three influencing factors:the radius R of the watercooled pipe,and the pipe spacing L₁ and L₃.The influence rule of different factors on the cooling effect and thermal stress of the plate were studied,for which the influence rank was respectively R>L₁>L₃ and L₃>R>L₁.The highest temperature value decreased when R and L₁increased,and the maximum thermal stress value dropped when R,L₁ and L₃ increased.The final optimized results can be summarized as:R equals 6 mm or 7 mm,L₁ equals 19 mm,and L₃ equals 20 mm.Compared with the initial design,the highest temperature value had a small decline,and the maximum thermal stress value dropped by 19%to 24%.So it was not ideal to improve the cooling effect by optimizing the geometry sizes of the water-cooled structure,even worse than increasing the flow speed,but it was very effective for dropping the maximum thermal stress value.The orthogonal experimental method reduces the number of experiments by 80%,and thus it is feasible and effective to optimize the water-cooled structure of the divertor plate with the orthogonal theory.     

Recent Progress of the HL-2A Multi-Channel HCOOH Laser Interferometer/Polarimeter

A multichannel methanoic acid（HCOOH,λ= 432.5μm） laser interferometer/polarimeter is being developed from the previous eight-channel hydrogen cyanide（HCN,λ=337 μm） laser interferometer in the HL-2A tokamak.A conventional Michelson-type interometer is used for the electron density measurement,and a Dodel-Kunz-type polarimeter is used for the Faraday rotation effect measurement,respectively.Each HCOOH laser can produce a linearly polarized radiation at a power lever of ³0 mW,and a power stability <10%in 50 min.A beam waist（diameter d₀≈12.0 mm,about 200 mm away from the outlet） is finally determined through a chopping modulation technique.The latest optical layout of the interferometer/polarimeter has been finished,and the hardware data processing system based on the fast Fourier transform phasecomparator technique is being explored.In order to demonstrate the feasibility of the diagnostic scheme,two associated bench simulation experiments were carried out in the laboratory,in which the plasma was simulated by a piece of polytetrafluoroethene plate,and the Faraday rotation effect was simulated by a rotating half-wave plate.Simulation results agreed well with the initial experimental conditions.At present,the HCOOH laser interferometer/polarimeter system is being assembled on HL-2A,and is planned to be applied in the 2014-2015 experimental campaign.     

Instructions for Manuscript Preparation

<正>Plasma Science and Technology(PST)is a journal reporting novel experimental and theoretical results and progress of interdisciplinary and application sciences in the fields related to Plasma Physics.Specific interested areas include:basic plasma phenomena;magnetically confined plasma;inertially confined plasma;astrophysics and space plasma;low temperature plasma;plasma     

高速旋转氚钛靶系统设计和靶温度的数值模拟

给出了用于强流中子发生器的高速旋转氚钛靶系统的设计方案,并对靶的温度变化进行了数值模拟,给出了强流中子发生器的运行参数。     

Hydrodynamic characteristics of an experimental model of the target in the MK-1 liquid-metal target system

The results of an experimental study of the hydrodynamics of air flow in a model of a liquid-metal lead-bismuth target of a 600 kW MK-1 system are presented. The shape of the experimental model corresponded precisely to that of a real target; the scale of the linear dimensions was 1:1. The Reynolds number for air flows in the model and a liquid-metal lead-bismuth alloy in the target were approximately the same. The hydraulic resistance of the target shape was determined experimentally. The main hydraulic characteristics of the coolant in the heat-stressed sections of the target are presented graphically. The design of the washer for the the flow part of the target is such that it smoothes the velocity field and velocity pulsations in the energy-dense section of the target. __________ Translated from Atomnaya énergiya,Vol. 101, No. 3, pp. 189–197, September, 2006.     

Neutronic characterization of the MEGAPIE target

The MEGAPIE project aimed to design, build and operate a liquid metal spallation neutron target of about 1 MW beam power in the SINQ facility at the Paul Scherrer Institut (Villigen, Switzerland). This project is an important step in the roadmap towards the demonstration of the accelerator driven system (ADS) concept and high power liquid metal targets in general. Following the design phase, an experimental program was defined to provide a complete characterization of the facility by performing a “mapping” of the neutron flux at different points, from the center of the target to the beam lines. The neutronic performance of the target was studied using different experimental techniques with the goals of validating the Monte Carlo codes used in the design of the target; additionally, the performance was compared with the solid lead targets used before and after the MEGAPIE experiment.     

Safety assessment of a lithium target

This paper addresses the safety assessment of the lithium target of the International Fusion Materials Irradiation Facility (IFMIF) through evaluating the most important risk factors related to system operation and verifying the fulfillment of the safety criteria. The hazard assessment is based on using a well-structured Failure Mode and Effect Analysis (FMEA) procedure by detailing on a component-by-component basis all the possible failure modes and identifying their effects on the plant. Additionally, a systems analysis, applying the fault tree technique, is performed in order to evaluate, from a probabilistic standpoint, all the relevant and possible failures of each component required for safe system operation and assessing the unavailability of the lithium target system. The last task includes the thermal–hydraulic transient analysis of the target lithium loop, including operational and accident transients. A lithium target loop model is developed, using the RELAP5/Mod3.2 thermal–hydraulic code, which has been modified to include specific features of IFMIF itself. The main conclusions are that target safety is fulfilled, the hazards associated with lithium operation are confined within the IFMIF security boundaries, the environmental impact is negligible, and the plant responds to the simulated transients by being able to reach steady conditions in a safety situation.     

同位素208Pb靶的制备

介绍了一种弧形靶框夹芯^208pb靶的制备工艺,包括核靶的制备装置和制备方法、核靶厚度和均匀性的控制和测量方法,并对结果进行了讨论.制备采用旋转蒸镀法,该法可以大大提高材料的利用率.所制靶的结构为30μg/cm^2 C＋361 μg/cm^2 ^208pb＋15 μg/cm^2 C,同一次所制的靶平均厚度为361μg/cm^2,不均匀性小于9.8%.其性能能够很好地满足超重核实验研究的要求.     

Reduction of the induced radioactivity in an ADS target by changing the target material isotope composition

In the paper a possibility of using in a target of an accelerator driven system (ADS) a modified lead–bismuth eutectic (LBE) in which natural lead (Pb-nat) is replaced by a lead isotope, Pb-208, is considered. Spectra of neutrons inside and outside the target consisted from the modified LBEs, Pb-208(80%)–Bi(20%) and Pb-208(90%)–Bi(10%), are calculated using Monte Carlo code. It is shown that in such the targets a harder spectrum of neutrons is realized as compared with the spectrum of the conventional target LBE, Pb-nat(45%)–Bi(55%). The induced activity of such the modified LBE target is reduced due to depleting the material with neutrons of intermediate energy, 10–100 keV and reducing a share of bismuth in the LBE from 55% down to 10–20%.     

The analysis of thick target metal alloys

The application of proton induced X-ray emission (PIXE) for elemental analysis of metal alloys was studied. A simple correction function is introduced, which takes into account thick target effects. Calibration standards are thus avoided and the concentrations are obtained from X-ray production cross sections. The method was tested and good agreement was found between the reference and measured concentrations.