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ITER聚变装置在运行过程中会产生大量的灰尘,当发生事故冷却水进入时,与热的灰尘发生反应产生氢气。氢气聚集后可能会燃烧甚至爆炸,对装置产生破坏。运用CFD的方法对“Wet Bypass”事故后反应产生的氢气风险进行了分析评价,得出在事故的初始阶段氢气达到了燃爆的风险,不同流量的冷却水泄漏进入真空室内会带来不同的氢气风险强度,在冷却水进入量十分大的情况下会惰化灰尘产生的氢气风险。并对注入二氧化碳惰化真空室气体空间的措施进行了分析,在事故发生的初期以较大速率充入二氧化碳能够降低氢气带来的风险。     

超导直线加速器腔体β_g选取问题的研究

超导直线加速器腔体几何β选取是否合适,直接影响到所需要的腔体类型(腔型)和腔体的总量,进而影响加速器的造价。采用线性近似的物理模型,并结合粒子群优化算法,开发出一套用来选择腔体几何β的程序。将之运用到中国加速器驱动次临界系统(C-ADS)质子直线加速器的设计中,得出一组最合适的βg和对应的物理设计方案。与现有的设计方案相比,新的设计方案的腔型个数少一个,而腔体总数基本不变,具有一定优势,同时也验证了本模型及优化算法的正确性。     

新型闪光X射线设备设计方案

本文叙述了我们正在研制的新型闪光X射线设备的设计方案。其主要特点是:(1)毫微秒脉冲发生器采用组件式结构与美国Hewlett-Pac ard公司的产品相似,(2)减少了Marx发生器回路的电感,可提高闪光X射线设备的输出电压及减少设备的体积,(3)采用多级触发,扩展了球隙开关的触发工作范围,(4)采用多尖阴极的爆炸发射闪光X射线管,增加了闪光X射线管的输出剂量及寿命。 改进后的设备,将达到和部份超过美国Hewlett-Packard公司产品的性能。     

Preliminary investigations of Monte Carlo simulations of neutron energy and let spectra for fast neutron therapy facilities

No fast neutron therapy facility has been built with optimized beam quality based on a thorough understanding of the neutron spectrum and its resulting biological effectiveness. A study has been initiated to provide the information necessary for such an optimization. Monte Carlo studies will be used to simulate neutron energy spectra and LET spectra. These studies will be bench-marked with data taken at existing fast neutron therapy facilities. Results will also be compared with radiobiological studies to further support beam quality optimization. These simulations, anchored by this data, will then be used to determine what parameters might be optimized to take full advantage of the unique LET properties of fast neutron beams.This paper will present preliminary work in generating energy and LET spectra for the Fermilab fast neutron therapy facility.     

Influence of annealing at temperatures above the solidus temperature on the structure and galvanomagnetic properties of Bi<Subscript>92</Subscript>Sb<Subscript>8</Subscript> solid-solution thin films

The influence of the annealing temperature from the interval between the solidus and liquidus temperatures of Bi₉₂Sb₈ solid solution on its structure and galvanomagnetic and thermoelectric properties has been studied. It has been shown that films of bismuth–antimony solid solution grown by thermal evaporation in a vacuum will have a large-grained structure after annealing at temperatures higher than the solidus temperature of the solid solution. It has been found that these films offer the lowest resistivity, the highest relative magnetoresistance, and the highest mobility of charge carriers. As the annealing temperature approaches the liquidus temperature, the probability that a dendritic structure will form and antimony-enriched regions will appear grows. This causes an increase in the charge carrier concentration and a decrease in the resistivity with a decrease in the relative magnetoresistance and charge carrier mobility.     

Statistical potentials for 3D structure evaluation:From proteins to RNAs

Structure evaluation is critical to in silico 3-dimensional structure predictions for biomacromolecules such as proteins and RNAs.For proteins,structure evaluation has been paid attention over three decades along with protein folding problem,and statistical potentials have been shown to be effective and efficient in protein structure prediction and evaluation.In recent two decades,RNA folding problem has attracted much attention and several statistical potentials have been developed for RNA structure evaluation,partially with the aid of the progress in protein structure prediction.In this review,we will firstly give a brief overview on the existing statistical potentials for protein structure evaluation.Afterwards,we will introduce the recently developed statistical potentials for RNA structure evaluation.Finally,we will emphasize the perspective on developing new statistical potentials for RNAs in the near future.     

在JYFL开展的研究工作：等离子体势的测量、电子加热的模拟、JYFL-MMPS及高温炉子

Extensive plasma potential measurements have been carried out using a device developed at JYFL. In this article the main results of the measurements will be summarized.A new simulation code to study the electron heating is being developed.One objective of the code is to determine the change of the electron loss cone when the magnetic field component of the electromagnetic wave is taken into account along with the permittivity of the plasma.As a part of the work,accurate X-ray measurements have been initiated. A new plasma chamber based on the MMPS-concept(Modified MultiPole Structure)has successfully been constructed and tested with the JYFL 6.4GHz ECRIS.The results and conclusions will be presented elsewhere in these proceedings.In the same article,a new concept of ECRIS and first results will be presented.The active development work of evaporation ovens has been carried out in a joint European collaboration(ISIBHI). The objective of the task is to make the operation of the oven reliable at 2000℃for several days.Both resistively and inductively heated ovens have been studied and further developed.The status of this work will be presented.     

Dynamic behaviours of a full floating ring bearing supported turbocharger rotor with engine excitation

The rotor dynamic behaviour of turbochargers (TC) has been paid significant attention because of its importance in their healthy operation. Commonly, the TC is firmly mounted on engines and they will definitely suffer from the vibrations originated from engines in operation. However, only a limited number of papers have been published with consideration of this phenomenon. In this paper, a finite element model of a TC rotor supported by nonlinear floating ring bearings has been established. The nonlinear bearing forces have been calculated by a newly proposed analytical method. An efficient numerical integration approach has been employed to conduct the investigation including the traditional unbalance and the considered engine excitation effects in question. The results show that the unbalance will place considerable influence on the rotor response at a low working speed. At high speeds, the effect will be prevented by the dominant sub-synchronous vibrations, which also prohibit the appearance of a chaotic state. The novel investigation with the proposed model considering engine excitation reveals that the engine induced vibration will greatly affect the TC rotor response at relatively lower rotor speeds as well. At higher speed range, the dominant effect of sub-synchronous vibrations is still capable of keeping the same orbit shapes as that without engine excitation from a relative viewpoint.     

The mechanical optical fiber splice for the 1990s

Splicing of optical fibers will be a major determining factor in the technical and economic success of fiber networks built in the 1990s. Needs, requirements, and specifications are now being proposed for the splicing systems to be used in these future networks. Two basic objectives for the splicing system of the 1990s can be defined from all the study and analysis that has been done thus far. Simply stated, the most widely accepted splicing system for the future will be the one that provides the highest performance at the lowest installed cost.

A new splicing system has been developed that addresses and meets many of the requirements that have been proposed. This system provides high splice performance and at the same time is very easy and fast to use. It also has low-cost assembly tooling and has been exhaustively tested to ensure conformance with proposed performance specifications.     

The mechanical optical fiber splice for the 1990s

Splicing of optical fibers will be a major determining factor in the technical and economic success of fiber networks built in the 1990s. Needs, requirements, and specifications are now being proposed for the splicing systems to be used in these future networks. Two basic objectives for the splicing system of the 1990s can be defined from all the study and analysis that has been done thus far. Simply stated, the most widely accepted splicing system for the future will be the one that provides the highest performance at the lowest installed cost.

A new splicing system has been developed that addresses and meets many of the requirements that have been proposed. This system provides high splice performance and at the same time is very easy and fast to use. It also has low-cost assembly tooling and has been exhaustively tested to ensure conformance with proposed performance specifications.     

北京慢正电子强束流运行性能测试

慢正电子强束流采用高能脉冲电子束流轰击金属钽靶, 以产生正负电子对的方式提供正电子, 作为慢正电子束流方法学研究和薄膜材料缺陷研究的束流基础. 本文是在该装置实现运行后, 对慢正电子束流的强度、能散、形貌等运行性能的测试工作的介绍, 以及慢正电子湮没多普勒测量系统的调试和标准样品的测量结果.     

Offspec, the ISIS spin-echo reflectometer

OffSpec has been purposely built as a low background, polarised neutron reflectometer with spin-echo for Larmor labeling. The instrument received first neutrons in December 2008 and five of the intended seven modes of operation have now been tested and operated with peer reviewed user experiments. The technical performance of the instrument will be reviewed in each of the modes and future scientific possibilities discussed. Particular attention will be paid to results from spin-echo SANS (SESANS) and spin-echo resolved grazing incidence scattering (SERGIS), where the largest number of measurements have been performed.     

光学表面光散射特性分析

通过对光学表面光散射特性的研究,结果表明:光散射强度随入射光波长的增加而减小,随表面粗糙度增加而增加.     

Plasma-hydrogenated microwave and optoelectronic devices

Hydrogen passivation of impurities, both donors and acceptors in GaAs and in InP based materials reduces free carriers concentration and produces layers with resistivity which can be adjusted to a desired value. Such phenomena can be used in the technological process of realisation of various devices and in this paper, applications to the fabrication of GaAs and InP based optoelectronic lasers on the one hand and of GaAs field effect transistors on the other will be presented. In both cases, the technological process which has been used and the performance which has been obtained will be described.     

Hydrogen vibrations at transition metal surfaces

Chemisorbed hydrogen has been studied on a variety of simple and composite transition metal surfaces using local density functional calculations. The goal of these studies is to elucidate trends and general principles in bond energies, atomic geometries, vibrational frequencies, and dynamic effective charges. The theoretical approach, based on the linear augmented plane wave method, will be reviewed. Results will be discussed for H in 2-, 3-, and 4-fold sites on W(001), Ru(0001), Cu(111), Pt(111), Rh(001), and the metal overlayer systems Cu-Ru(0001) and Ni-W(001). In most cases, all the harmonic vibrational modes were studied. Some anharmonic effects were examined. While good agreement has been obtained with much of the available experimental data, some outstanding disagreements will be discussed. Our results will be compared with the nearest-neighbor harmonic potential model and effective medium approach.     

Observation of the spectrum of Ne-like Ar 46.9 nm soft X-ray and the laser under different main current rise time

Ne-like Ar 46.9 nm soft X-ray laser has been realized by the main current with different rise time. In this paper, the spectrum of capillary discharge Ne-like Ar 46.9 nm soft X-ray laser has been detected using a Rowland spectrograph, a new method of changing the rise time of the main current is also researched when the other conditions are fixed. The rise time will be changed when altering the inductance of the main switch, which will influence the time of lasing onset and the energy of the laser output. The time of lasing onset will be postponed and the energy of the laser will increase when the induction of the main switch increases. The energy of the laser increase by 78.5% when the rise time is changed from 38 to 55 ns.     

极化子单激发态的反向极化研究

通过对有机高分子中极化子的单激发态进行研究，发现该态在外电场下呈现反向极化特征，极化规律与双激子态类似.在强电场下，反向极化消失，极化子单激发态解离为一个单极化子和一个双极化子态. 关键词： 极化子态 激子态 反向极化     

Coupled metallic ring gap waveguide

Employing the surface plasmon polaritons (SPPs), a kind of coupled metallic squareness ring waveguide structure is presented. Its properties has been analyzed with the finite different time domain method and the coupling length has been derived from the coupled mode theory. It is demonstrated that the SPPs excited by the light with different wavelength will come out from different output port due to different coupling length. By appropriately designing the structure, it can be utilized to realize some optics devices such as multiple-wavelength sorter and beam splitter. This will break through the diffraction limit of traditional optical devices.     

准绝对式光学编码器

准绝对式编码器继承了绝对式和增量式光学编码器的优点,根据串行位置编码的基本原理,借助计算机辅助设计,获得了全周100个位置的编码方案,设计了相应的准绝对式编码器;通过与两种传统编码器特点的比较,突出了准绝对式光学编码器的显著特点,指明了其未来良好的应用和发展前景.     

GENIUS - a new facility of non-accelerator particle physics

The GENIUS ( rmanium in Liquid trogen nderground etup) project has been proposed in 1997 [1] as first third generation double beta decay project, with a sensitivity aiming down to a level of an effective neutrino mass of < m > 0.01 - 0.001 eV. Such sensitivity has been shown to be indispensable to solve the question of the structure of the neutrino mass matrix which cannot be solved by neutrino oscillation experiments alone [2]. It will allow broad access also to many other topics of physics beyond the Standard Model of particle physics at the multi-TeV scale. For search of cold dark matter GENIUS will cover almost the full range of the parameter space of predictions of SUSY for neutralinos as dark matter [3,4]. Finally, GENIUS has the potential to be the first real-time detector for low-energy (pp and ⁷Be) solar neutrinos [6,5]. A GENIUS-Test Facility has just been funded and will come into operation by end of 2001.