6H-SiC JFET 输出特性及其中子辐照模型

基于沟道调效应、串联电阻效应的考虑,首先建立了一个和实验室符合很好的６Ｈ－ＳｉＣＪＦＥＴ的模型,在该模型中采用了两种电离杂质模型和Ｃａｕｇｈｅｙ－Ｔｈｏｍａｓ方程,接着在分析中子辐照对ＳｉＣ ＪＦＥＴ电参数如电子浓度、迁移率、电阻率和空间电荷区密度影响的基础上,对ＳｉＣ ＪＦＥＴ在室温和３００℃时的辐照响应进行了模拟。模拟结果和实验相符。     

酸性铁蛋白放免分析中抗体纯化的可行性

用改进的工艺自人心肌组织中提取的高纯度酸性铁蛋白，与经溴化氰活化ＳｅｐｈａｒｏｓｅＣＬ－６Ｂ偶联，制得ＡＩＦ－ＳｅｐｈａｒｏｓｅＣＬ－６Ｂ亲和层析柱。用经柱纯化的兔抗ＡＩＦ抗血清来组建酸性铁蛋白放免分析法用四参数Ｌｏｇｉｓｔｉｃ数据处理程序处理数据。     

KrF激光受激布里渊散射脉宽压缩的研究

用线宽０．５ｃｍ＾－１，脉宽２３ｎｓ的ＫｒＦ激光在ＳＦ６气体和液体环已烷中进行了受激布时散射脉宽压缩的实验研究。测量了脉宽压缩效果和ＳＢＳ反射率随泵浦光能量，气体气压，透镜焦距，焦点位置等实验条件的变化关系，分析了讨论了气体气压，透镜瑞利范围对ＳＢＳ阈值的影响。     

CMOS 运算放大器的总剂量辐射响应和时间退火特性

对ＣＭＯＳ运算放大器ＬＦ７６５０进行了１ＭｅＶ电子的电离辐照实验，研究了ＬＦ７６５０的总剂量电离辐射响应特性和抗总剂量辐射水平，并通过研究其辐照后在室温和１００℃高温条件下电离辐照敏感参数随时间的变化关系，分析了在电离辐射环境下ＣＭＯＳ运算放大器的损伤机制及参数失效机理。     

CMOS运算放大器的部剂量辐射响应和时间退火特性

对ＣＭＯＳ运算放大器ＬＦ７６５０进行了１ＭｅＶ电子的电离辐照实验，研究了ＬＦ７６５０的总剂量辐射响应牧场生和抗总剂量辐射水平，并通过研究其照后在室温和１００℃高温条件下电离辐照敏感参数随时间的变化关系，分析了在电离辐射环境下ＣＭＯＳ运算放大器的损伤机制及参数失效机理。     

一次性使用输液器初始污染的调查及灭菌剂量的确定

对６２４件医用一次性输液器的初始污染数据做了统计了分分析，做出了初污梁的正态分布图，展示输液器内壁与外壁初污染的关系，并以实验数据说明了灭菌前输液器中初污染的变化情况。按伽玛辐射灭菌剂量的确定方法实验测量平均初始污染量为７ＣＦＵ／件（ＣＦＵ为菌落形成单位），灭菌保证水平（ＳＡＬ）为１０＾６，取样比例（ＳＩＰ）为１，算得灭菌剂量为１７．２ｋＧｙ。     

47MeV／u的C^6^＋在CaVSn：YIG中辐照效应的研究

用兰州重离子研究装置（ＨＩＲＦＬ）首次进行了４７ＭｅＶ／ｕ的Ｃ＾６＾＋离子辐照ＣａＶＳｎ：ＹＩＧ的实验。通过穆斯堡尔效应和正电子寿命测量对４７ＭｅＶ／ｕ的Ｃ＾６＾＋离子在ＣａＶＳｎ：ＹＩＧ中的辐照效应进行了初步研究。发现辐照导致内磁场方向趋于各向同性分布，由穆斯堡尔谱未观察到非晶化现象。缺陷的数量随Ｃ＾６＾＋离子在样品中电子能量损失的增加而增加。     

非晶合金Fe_（73．1）Cu_（1．2）Nb_（3．2）Si_（12．5）B_

采用Ｍ　ｓｓｂａｕｅｒ效应和ＸＲＤ分析方法研究了非晶合金Ｆｅ７３．１Ｃｕ３．２Ｎｂ３．２Ｓｉ１２．５Ｂ１０．０的晶化。实验表明，该非晶合金有两个晶化阶段。在第一阶段晶化后，样品主要由ＤＯ３型的ａ—ＦｅＳｉ合金的超细颗粒和作为晶界的非晶相两部分组成。随着退火温度的上升，晶化相的含量增加，非晶相含量减少、在第二阶段晶化后，残余的非晶相就晶化为Ｆｅ２Ｂ和Ｆｅ２３Ｂ６化合物以及可能为Ｆｅ－Ｎｂ－Ｂ之类的顺磁相。     

非晶合金Fe73.1Cu1.2Nb3.2Si12.5B10.0晶化的Mossbauer研究

采用Ｍｏｓｓｂａｕｅｒ效应和ＸＲＤ分析方法研究了非晶合金Ｆｅ７３．１Ｃｕ１．２Ｎｂ３．２Ｓｉ１２．５Ｂ１０．０的晶化。实验表明，该非晶合金有两个晶化阶段。在第一阶段晶化后，样品主要由ＤＯ３型的α－ＦｅＳｉ合金的超细颗粒和作为晶界的非晶相两部分组成。随着退火温度的上升，晶化相的含量增加，非晶相含量减少。在第二阶段晶化后，残余的非晶相就晶化为Ｆｅ２Ｂ和Ｆｅ２３Ｂ６化合物以及可能为Ｆｅ－Ｎｂ－Ｂ之类的顺     

低剂量离子在物体样品中透射行为的研究

利用金硅面垒探测器测量低剂量率的Ｆ离子在生物组织样品（洋葱内表皮和芸豆种皮）中的透射能谱,用来研究荷能离子在生物样品中的能损和深度分布,实验中Ｆ离子能量为９００ｋｅＶ－６ＭｅＶ剂量率大约为１０＾４ｉｏｎｓ／ｓ·ｃｍ＾２。用ＳＥＭ观测样品在离子束轰击下可能发生的损伤,实验中测量了了不同能量离子样品中的透射能谱,利用ＳＩＮＲＡ对测量得到的透射能谱进行了拟合分析,并讨论了生物样品的特殊结构对透射能谱和离     

Feasibility study on the applicability of a diffusion-welded compact intermediate heat exchanger to next-generation high temperature gas-cooled reactor

The development of an intermediate heat exchanger (IHX) transferring high temperature heat to a process heat application is of prime importance for a next-generation high temperature gas-cooled reactor (HTGR). The IHX needs high structural integrity and reliability over 900°C for a long duration. A plate fin type compact heat exchanger (PFCHX) has a large heat transfer area per heat exchanger volume and is expected to be used as the IHX. However, the brazing for connecting fins and plate is not reliable when existing PFCHXs are used in a high temperature condition for a long time. We have proposed a concavo-convex plate type compact heat exchanger (CPCHX) which consists of concavo-convex plates (CPs) welded by solid state diffusion and made of nickel-based superalloy Hastelloy XR. In our study, first, an optimized condition for the solid state diffusion welding between the CPs of the CPCHX was found by experiments using test pieces made of Hastelloy XR. Second, small-scale diffusion-welded CPCHXs were designed, manufactured and installed in a test loop to investigate the reliability of the diffusion welding. As a result of leakage tests, it was confirmed that the reliability of the solid state diffusion welding between the CPs of the small-scale CPCHX is sufficient. A thermal performance test revealed that the thermal conductance of the small-scale CPCHX was better than calculated. In addition, a design study for the CPCHX was performed to investigate the feasibility of the diffusion-welded CPCHX to the IHX in a next-generation HTGR.     

Diffusion Calculation Model for Streaming Effects in Low Density Channels in LMFBRs

A study is made of the use of modified diffusion theory to calculate the negative reactivity worth of recently proposed flow activated reactor shutdown devices, in which sodium is voided from purely sodium filled channels located at the boundary between the core and the radial blanket in a Liquid Metal cooled Fast Breeder Reactor (LMFBR). Three-dimensional diffusion theory calculations using various definitions of modified diffusion coefficients in the channels are compared with each other and with three-dimensional transport theory computations. While normal diffusion coefficient is found to be inadequate for these reactivity worth calculations, the various modified diffusion coefficients appear adequate for the considered case. Modelling method of the small thickness of steel wall and interstitial sodium layer of the modules are also studied.     

Recovery Rate and Capacitance Measurements on Irradiated Lithium-Containing Solar Cells

Room temperature recovery kinetics of lithium-containing p/n silicon diodes and solar-cells were experimentally investigated after irradiation by 1 MeV electrons to fluences of 1013 and 1014 e/cm2. The current physical model for the recovery process involves the diffusion of a lithium donor ion to a radiation-induced vacancy-impurity defect with negative charge and high hole-capture cross section, and the complexing of the lithium donor with this defect to form a new defect with zero charge and low hole-capture cross section. The recovery rate thus depends on the lithium ion density, the lithium-ion diffusion constant, and the defect density. Direct measurements of the density profile of lithium ions in the base region near the junction have been performed on 12 diodes. Using a capacitive technique with some novel features, effective diffusion constant for lithium ions near the junction was measured on the same diodes. Further useful information has been obtained by relating these properties to the rapid, room temperature recovery of minority-carrier diffusion length which is observed in these devices after irradiation. The results show that: ? Steep gradients of lithium ion density (~1019 cm-4) exist in the base region extending, in many cells, to a distance greater than 10 micrometers from the junction; ? In a group of cells made from Lopex silicon, the effective lithium diffusion constant at the junction edge ranged from 0.05 to 0.28 times the free lithium ion diffusion constant and, in a group of cells made from float-zone refined silicon, from 0.1 to 1.     

Fuel Microstructural Analysis of Incubation Burn-Up for Fission Gas Release

A study was made on an incubation burn-up for fission gas release using fuel swelling microstructural analysis. Conclusions of the study are: (1) The fuel microstructural analysis successfully determined the incubation burn-up. The analyzed values agreed with those estimated by the Halden empirical gas release model. (2) The incubation burn-up obtained from the Halden model was correlated with the fuel center temperature, but the micro-structural analysis was more dependent on the local fuel swelling temperature. (3) The incubation burn-up was attributed to the grain boundary diffusion process and the fuel local gaseous swelling.     

Application of ‘natural coordinate system’ in the finite element solution of multigroup neutron diffusion equation

A simple method of generating stiffness matrices for the solution of multigroup diffusion equation by ‘natural coordinate system’ has been presented. A comparative study has been made using triangular elements with linear model, triangular elements with quadratic model and rectangular elements with bilinear model to demonstrate their relative efficiencies. The quadratic interpolation model has been shown to be superior to linear and bilinear models with respect to computing time, computer storage and relative error in K_eff for a two group diffusion example. The flexibility of the finite element treatment has been demonstrated by the calculation of the reactivity of a partially inserted control rod. Good agreement has been obtained with a perturbation calculation.     

Investigation of nonrecoil fission-product release phenomena using multifrequency source-perturbation experiments in EBR-II

A widely-accepted theory that was proposed to explain nonrecoil fission-product release phenomena in LMRs postulated that isotopic transport kinetics are attributable to liquid-state diffusion across a viscous sublayer of Na near the surface of the fuel. A series of multifrequency source-perturbation experiments was recently performed in EBR-II to isolate and quantitatively explore the boundary-layer diffusion mechanism while separating out all other physical variables that affect the isotopic transport kinetics. Detailed analyses of the results using bivariate spectral decomposition and cross-correlation techniques are presented. Results of the analyses provide incontrovertible experimental evidence that boundary-layer diffusion in fact plays no part in the release of short-lived fission products in LMRs. A major conclusion of this investigation is that all nonrecoil fission-product release phenomena originate from mechanisms acting inside the breached element itself. Implications of this and other findings made during this investigation are discussed, and recommendations are made for extending the techniques introduced here in future experiments involving actual breached pins.     

模型库技术在核化事故危害预测中的应用研究

针对核化事故危害预测模型多环节、多模型、模型间具有继承性的特点,以核化事故中放射性物质及有害化学品大气扩散模型为重点,应用面向对象方法建立模型基本体系,并在此基础上论述了基于决策支持的核化事故危害预测模型库系统的设计和实现技术。     

Model to simulate high temperature oxidation kinetics of zircaloy-4: Parabolic and linear behaviour

A calculation code to simulate parabolic and linear behaviour of Zircaloy-4 oxidation between 600 and 862°C in water vapour was developed. This code consists of solving the diffusion equations by the finite-difference method. This method in its explicit version was employed previously, but this type of calculation becomes impracticable with present-day computers when attempts are made to simulate long-term experiments (24 h). This is why the implicit finite-difference method is proposed here: this method has the advantage of drastically reducing the calculation time. The code allowed us to calculate the relationship between the oxygen mass in theα-phase to the total oxygen mass, the oxide thickness and the diffusion profile of oxygen in the α-phase.The results obtained with the model are compared with experimental data existing in the literature for Zircaloy-4, although it could be applied to pure zirconium or other zirconium alloys if more experimental data were available. The singular behaviour of the diffusion profiles in the α-phase during linear kinetics is particularly analyzed.This work is part of a programme to study the oxide-metal interface movement during vapour oxidation of Zircaloy-4 subjected to temperature transients. Knowledge of this is of vital importance for evaluating mechanical properties of fuel claddings during possible loss of coolant accidents in nuclear power reactors.     

Market potential of small and medium-size nuclear reactors as combined heat and power plants in Europe

The preliminary results are presented concerning a study launched by the Commission of the European Communities to assess the potential market of small and medium-size nuclear reactors through EC Member countries. The study was aimed at identifying those factors that may have a role in shaping the eventual deployment and diffusion of this class of nuclear reactors. In a first phase, attention focused on modular high-temperature gas-cooled reactors that would be installed to produce low-temperature heat and power. Federal Republic of Germany, Italy and France are the countries for which the investigation has been completed. The time span of interest is up to the year 2020. Referring to this horizon, an appraisal has been made of the number of nuclear units which could come on line to cope with energy demand and their timing. Through the study a distinction is made between technical potential, economic potential, and effective market potential. It is understood indeed that both economic competitiveness towards other energy sources and also institutional or organizational factors may restrict the market which could become accessible and would be covered by the new nuclear plants.     

Diffusion analysis on the thermal release of tritium from a neutron absorbing material

Tritium released from neutron irradiated borosilicate glass was determined by a specially designed sampling system and a liquid scintillation counter at temperatures in the range of 200–700°C. It was found that the chemical form of tritium released was tritiated water (HTO, T₂O) for the most part. Tritium produced in the glass would react with oxygen to form OT and diffuse out by a similar mechanism as the molecular diffusion of water in glasses. The diffusion coefficient of tritiated water in borosilicate glass obtained is expressed by D (cm²/s) = 5.3 × 10⁻⁴ exp( −128 kJ/mol)/RT). It is concluded from the diffusion analysis that the greater part of tritium produced in a neutron absorber, which is made of borosilicate glass, would remain in the glass for a few years of irradiation.