Model-based approach for quality improvement of electron beam welding applications in mass production

A model-based approach is presented to obtain a definite geometry of the seam as well as to find the regimes where the results will repeat with less deviation from the desired values in the electron beam welding. Using the response surface methodology, polynomial regression models for the behaviour of weld depth and the weld width are found. In order to improve the quality of the process in mass production, by a decrease of the deviation from a target value of the performance characteristic, parameters in two models describing the mean value and the variance for the weld depth and for the weld width in mass production are estimated. Using these models quality improvement, defined as an optimisation problem to produce reproducible welds while keeping the mean value of weld depth or/and width constant, is discussed. This approach is applied to the electron beam welding of stainless steel, for beam powers in the region of 4.2-4.8 kW and welding speeds of 3.333-13.333 mm/s.     

The simultaneous neutron and photon interrogation method for fissile and non-fissile element separation in radioactive waste drums

Measuring -emitters such as (^{234,235,236,238}U, ^{238,239,240,242,244}Pu, ²³⁷Np, ^241,243Am, …), in solid radioactive waste allows us to quantify the -activity in a drum and then to classify it. The simultaneous photon and neutron interrogation experiment (SIMPHONIE) method dealt with in this paper, combines both active neutron interrogation and induced photofission interrogation techniques simultaneously. Its purpose is to quantify fissile (²³⁵U, ^239,241Pu, …) and non-fissile (^236,238U, ^238,240Pu, …) elements separately in only one measurement. This paper presents the principle of the method, the experimental setup, and the first experimental results obtained using the DGA/ETCA Linac and MiniLinatron pulsed linear electron accelerators located at Arcueil, France. First studies were carried out with U and Pu bare samples.     

小肠RNA对小鼠电离辐射肠道损伤修复的差异基因表达的研究

为从基因水平探讨小肠糖核酸,促进小鼠电离辐射肠道操作修复的机理,采用随机分组法把９０只小鼠分成４组,建立辐射后给予４０μｇＲＮＡ治疗的实验组与０．４ｍＬ生理盐水治疗的对照组模型,分别于照射后６、１２、２４ｈ,４ｄ和８ｄ采集小肠空肠段标本,动用消减杂交基础上的ＬＤ－ＰＣＲ技术,分离实验组与对照组之间的差异表达基因。结果表明：实验组与对照组６、１２、２４ｈ,４ｄ和８ｄ的克隆新表达基因数分别为１８、２２     

信号转导和转录激活子5信号转导途径对受辐射KG-1细胞周期的调控作用

探讨信号转导和转录激活子５（ＳＴＡＴ５）信号转导途径在受辐射ＫＧ－１细胞中对细胞周期的调控作用。通过转染ＳＴＡＴ５基因的显性负突变体（ＤＮ－ＳＴＡＴ５）阻断ＪＡＫ／ＳＴＡＴ的信号传递后,瞬间转染ｃｙｃｌｉｎＤ１基因及ｃｙｃｌｉｎＢ１基因,观察ｃｙｃｌｉｎＤ１蛋白及ｃｙｃｌｉｎＢ１蛋白对受辐射细胞周期阻滞的影响作用。转染ＤＮ－ＳＴＳＡＴ５基因的受辐射ＫＧ－１细胞即使用粒－巨噬细胞集落刺激因子（ＧＭ－ＣＳＦ）刺激亦不能跳出Ｇ１期阻滞;瞬间转染ｃｙｃｌｉｎＤ１基因及ｃｙｃｌｉｎＢ１基因分别能促进受辐射细胞跳出Ｇ１期和Ｇ２期阻滞。ＧＭ－ＣＳ所激活的ＪＡＫ／ＳＴＡＴ信号转导途径通过促进周期蛋白ｃｙｃｌｉｎＤ１及ｃｙｃｌｉｎＢ１的表达而对受辐射细胞周期进行调控。     

12MeV、4.2kW电子直线加速器的辐照应用

研究了能量为６～１２ＭｅＶ、平均束功率为４．２ｋＷ的工业辐照用电子直线加速器的应用。结果表明,它在对改装半导体器件（二极管、三极管、可控硅）参数特性,大蒜辐照抑制发芽和食品辐照杀菌保鲜综合辐照加工方面更为合适。     

北京正负电子对撞机(BEPC)辐射监测系统的改进

介绍了北京正负电子对撞机辐射监测系统的改进情况。改进后的新系统不仅提高了人机界面的交互性、增强了辐射现场的实时性,还实现了辐射监测数据与高能所局域网的联网共享。     

不同剂量 X射线全身照射对小鼠胸腺细胞周期进程的影响

本文采用细胞计量术研究了不同剂量Ｘ射线全身照射后小鼠胸腺细胞周期进程的变化。结果表明,７５ｍＧｙ Ｘ射线全身照射后２４～７２ｈ胸腺细胞周期各时相细胞数目发生明显变化,Ｇ０／Ｇ１期细胞数低于对照组,Ｓ期细胞数增多,说明其ＤＮＡ合成能力增强,至７ｄ时达到对照组水平;２．０Ｇｙ全身照射后４ｈ时胸腺细胞便开始出现明显的Ｇ２阻滞,１２ｈＧ２阻滞达最高点,７２ｈ其细胞周期进程明显加快,至７ｄ时达对照组水平。不     

无内屏蔽彩管的地磁兼容性研究

地球存在着地磁场,地磁场对彩色显像管(CPT)的色纯度影响很大.为了减小地磁场对CPT色纯度的影响,通常在CPT内部装有磁屏蔽组件(简称为内屏蔽).本文介绍一种无内屏蔽组件的CPT,它既降低了CPT的成本,又不影响CPT的品位,还能满足全球地磁场的兼容性.     

Enhanced output power of (indium) gallium nitride light emitting diodes by a transparent current spreading-film composed of a disordered network of indium tin oxide nanorods

A thin film consisting of a disordered nanorod network of indium tin oxide (ITO) and conventional ITO films are fabricated on gallium nitride (GaN) based-light emitting diodes (LEDs) by electron beam evaporation. The surface morphologies are observed by scanning electron microscopy (SEM). The disordered nanorod network of ITO is grown in vacuum without oxygen. It can be applied directly on the LED as the current spreading film unlike other nanorods which require growth on a conductive layer. The transmittance, current–voltage characteristic, and the dependence of light output power on current are measured for disordered nanorod network ITO LEDs and conventional ITO LEDs, respectively. The measurement results indicate that the nanorod network provides a significant improvement in the light output power of GaN-based LEDs. The influence of the structure of ITO films on the light output power of GaN-based LEDs is discussed.