通道电子倍增器的性能研究

本文介绍用电子和正电子束流测试单通道电子倍增器的高压坪曲线、脉冲幅度分布和效率曲线;还用电子束流测试了阈电压和坪起始电压随电子能量的变化、增益随工作电压的变化、脉冲幅度与电子能量的关系、脉冲幅度和计数率随束流强度以及本底随工作电压的变化关系。     

血清TRAb放免检测在甲状腺疾病诊治中的价值

对甲状腺疾病患者（共758例,其中：初诊甲亢组166例,甲亢内科治疗甲功正常组198例,甲亢内科治疗甲功异常组86例,甲亢内科治疗甲减组24例,甲亢^131I治疗甲功正常组104例,亚甲组48例,单纯性甲腺肿组52例,原发性甲减组80例）及62例正常人的血清TRAb（促甲状腺激素受体抗体）浓度进行了放免检测。结果表明：初诊甲亢组甲亢内科治疗甲功正常组、甲亢内科治疗甲功异常组、 甲亢内科治疗甲减组、甲亢^131I治疗甲功正常组、原发性甲减组的血清TRAb明显增高,与正常对照组比较,P＜0．01,有显著性差异;亚甲炎组、单纯性甲状肿组的血清TRAb正常,与正常对照组比较,P＞0．05,无显著性差异。甲亢内科治疗甲功正常组的TRAb均值和阳性率与甲I治疗甲功正常组比较,皆P＜0．01,有显著性差异。由此可见,甲亢和原发性甲减患者血清TRAb为是甲亢、甲减的辅助诊断指标,也是甲亢和亚甲炎的鉴别诊断指标;同时,TRAb是评价机体自身免疫监护功能的重要指标,也是停用甲状腺药物的一项指标。     

Atomic-Oxygen Beam Source with Compact ECR Plasma

An atomic-Oxygen beam source with compact ECR plasma was succesfully investigated.the microwave was produced and transmitted in a coaxial mode,and coupled with the loop ,The plasma was produced as a higher asymmetry magnetic mirror field,and neutralized with the molybdenum target at a lower asymmetry magnetic mirror field.The magnetic field was constituted with permanent magnets.this source has a higher flux density of stom beam, a lower operating pressure ,a smaller power consumption and low-cost.When it was installed at the equipment to study the interaction of the beam with the surface,the operation was carried out very easily and with a good stability.     

A system for MBE growth and high-resolution RBS analysis

A UHV system is described, in which an MBE apparatus is combined with a setup for high-resolution RBS in conjunction with ion channeling and blocking and with facilities for RHEED, LEED and AES. This configuration makes it possible to grow atomic layers with excellent control over composition and thickness and to analyse the structure of these epitaxial films in situ with near-monolayer depth resolution.     

银粉的辐射清洁制备

采用辐射还原法制备纯净的银粉,期待通过改变反应条件制备出不同形貌的银粉,以满足实际应用中的各种要求。在常温常压氮气环境下,以草酸银为银源,水为介质,利用电子加速器辐照的方法制备银粉。通过扫描电镜和X射线衍射仪对银粉进行表征。结果表明,改变反应体系的pH值、吸收剂量和结构诱导剂的种类,可以制备出颗粒状、棒状、片状等不同形貌的银粉。在吸收剂量4 MGy、pH=6时,以CS005或CSH100为诱导剂,能得到长5~10mm,直径约2mm的棒状纯净银粉;以CS005和BTA为诱导剂,得到四边形的片状银粉;以CSH100和PEO200为诱导剂,得到三角形和多边形混杂的片状银粉。在总剂量4MGy、pH=9时,以CS005为诱导剂,得到粒径约20 nm的类球形纳米银粉;以CSH100为诱导剂,得到粒径约100 nm的片状混杂银粉。在总剂量8 MGy、pH=9时,以CS005或CSH100为诱导剂,得到粒径约100 nm的片状混杂银粉。     

系统性硬皮病心肌损害在冷诱导心肌断层显像和超声心动图的表现

应用＾９９ｍＴｃ－ＭＩＢＩ对２３例系统性硬皮病（ＳＳＣ）病人进行了心肌断层显像冷诱导试验,并同期应用于维超声心动图检测左心室功能和室壁运动。结果表明,１４例病人（６０．９％）有心肌放射性分布异常,其中３例可逆性缺陷６个节段,５例固定性缺损９个节段,６例两种缺损共存１４个节段;心脂显像异常率在雷诺现象（ＲＰ）组和无ＲＰ组之间显著性差异（０．５〉Ｐ〉０．２５）;心肌显像异常组病人的左室射血分数、每搏输     

2-甲基1，4-萘醌激发三重态与核酸反应的电子自旋共振自旋消减法研究

应用电子自旋共振（Electron spin resonance，ESR）自旋消减法，研究了内源性光敏剂2-甲基-1，4萘醌（VK3）的激发三重态（^3VK3^＊）与核酸及其组分的反应性顺序，得到。VK3^＊与四个核苷及四个单核苷酸的反应性顺序为Gua〉Ade〉Cyt〉Thy，dGMP〉dAMP〉dCMP〉TMP。结果与早前采用激光光解瞬态吸收光谱研究^3VK3^＊氧化DNA，测得的DNA及其组分阳离子自由基生成速率常数、核苷及核苷酸的氧化还原电位排序相一致。对^3VK3^＊与几种富含鸟嘌呤（G）的寡聚核苷酸：端粒DNA重复序列、端粒酶RNA亚基模版及其L6-P6发夹序列反应的ESR自旋消减法研究结果表明，其反应性大小与寡聚物中鸟嘌呤含量正相关，其中与端粒DNA的反应性最强。     

Fragmentation of positronium in collision with xenon

Cross-sections are presented, both integrated and differential with respect to the longitudinal energy of the ejected positrons, for the fragmentation of Ps in collisions with Xe at 18 and 30 eV impact energy and compared with available theory. The shapes of the positron spectra are also compared with those measured in collisions with He at the same impact energy.     

γ射线照射人肝细胞对BMP信号通路相关基因表达的影响

利用实时荧光定量PCR技术对人肝细胞株受不同剂量(0.1、0.2、0.5、1.0、2.0、4.0 Gy)⁶⁰Co γ射线照后不同时间点(6、12、24 h)的骨形成蛋白(BMP)信号通路相关基因表达的剂量和时间效应关系进行研究。结果显示,不同剂量照后不同时间点,BMP信号通路相关基因骨形成蛋白2(BMP2)、骨形成蛋白7(BMP7)、骨形成蛋白受体1A(BMPR1A)、骨形成蛋白受体1B(BMPR1B)、骨形成蛋白受体2(BMPR2)的溶解曲线均为单峰,均为特异性扩增产物。在不同照射剂量点BMP2的表达水平与照后时间呈正相关;BMP7在0.1、0.2、0.5 Gy的表达水平与照后时间呈负相关,在照后12和24 h的表达水平与照射剂量呈正相关;BMPR1A在0.1、0.2、1.0 Gy的表达水平与照后时间呈正相关;BMPR1B在0.2、0.5、1.0 Gy的表达水平与照后时间呈正相关,在4.0 Gy的表达水平与照后时间呈负相关;BMPR2在照后12 h的表达水平与照射剂量呈负相关。     

Evaluation of piping damage in German nuclear power plants

Information relating to piping damage in safety-relevant systems in German nuclear power plants with light water reactors (both pressurized water reactors (PWRs) and boiling water reactors (BWRs)) were analyzed with respect to the modes and the causes of damages. In general, the total range of observed piping damage is low. The incidents (82) in plants with PWRs affected mainly pipes with small diameters. Almost all damaged piping showed wall-penetrating cracks combined with leakages, which revealed the damage. Initial cracks at piping with larger diameters were discovered in isolated cases during in-service inspections. With regard to the incidents (71) in plants with BWRs, piping with small as well as large diameters was affected to different degrees. Wall-penetrating cracks combined with leakages were detected at piping with small diameters. For large-diameters pipes, cracks were indicated during in-service inspections and supplementary examinations. The results of the incident evaluations confirm the conservativeness of the safety concept chosen for the design of German nuclear power plants with light water reactors.     

Conditions for maximum fuel burnup in a RBMK channel reactor without a moderator

The conditions for attaining an operating regime with maximum burnup of nuclear fuel are examined. This can be a regime with steady continuous reloadings with the reactor replenished with fuel whose heavy atoms contain close to 50% of the fissioning material with average content 25% and burnup 35–50%. The possibility of improving the stability of the fuel elements with increasing cladding thickness and the role of different organs for compensating reactivity in a regime with steady continuous reloadings and maximum fuel burnup are examined. An assessement is made of the possibility of obtaining a negative or zero effect of reactivity with loss of coolant and developing nonproliferation measures.__________Translated from Atomnaya Énergiya, Vol. 98, No. 2, pp. 83–91, February, 2005.     

用^32S离子辐照法研究聚酯膜在红外光区的抗反射性能

为研究圆锥形径迹孔与多层镀膜结合对改善材料在红外光区的抗反射性能的影响,采用HI-13串列加速器提供的^32S离子分别辐照20μm和50μm厚的聚酯,用氢氧化钠和PEW溶液蚀刻后,两种聚酯表面的潜径迹成为孔径分别为0．5μm和3μm的径迹孔。在有径迹孔的样品表面,用真空蒸发依次镀上不同厚度的银、石墨和氟化镁或石墨和氟化镁。在2．5～10μm波段的红外光区测量表面全反射。结果显示,有径迹孔的样品表面镀上石墨和氟化镁后反射率可低至1％。径迹孔较深或两面有径迹孔且两面镀膜的样品,具有较强的材料表面抗反射性能。     

中波发射台周围地面场强计算结果与实测值比较分析

以某8塔共址的中波发射台为例,对多个不同发射功率的发射塔同时运行时地面电场强度进行40 V/m等值线标准方法的计算与实测。结果显示,仅2座发射功率≥50 kW发射塔周围可实测到40 V/m等值线,实测值与国家环境行业标准规定方法计算结果相差约30%。     

脉冲偏压对贫铀表面磁控溅射离子镀铝结合强度的影响

采用磁控溅射离子镀技术在不同偏压下于贫铀表面制备铝镀层，用扫描电镜和俄歇电子能谱仪对镀层形貌和界面元素分布进行分析，用拉伸法对镀层的结合强度进行测定。结果表明：在-900V脉冲偏压下所得镀层与铀基体结合良好，镀层与基体之间存在较为明显的“伪扩散区”；与直流偏压相比较，脉冲偏压所得镀层结合强度明显增强，镀层的致密性显著改善。     

~(125)I-白蛋白融合干扰素α2b大鼠体内分布研究

采用氯胺-T法对白蛋白融合干扰素α2b进行125I标记,PD-10柱纯化,三氯醋酸沉淀法测定放化纯;体外以WISH/VSV系统比较白蛋白融合干扰素α2b和125I-白蛋白融合干扰素α2b的抗病毒活性;SD大鼠皮下注射125I-白蛋白融合干扰素α2b,分别于给药后0.5、2、6、24、48、90、180、300 h放血处死,取血和相关脏器,称重并测定放射性,计算每克脏器放射性占注入量的百分率(%ID·g-1).结果显示,氯胺-T法制备的125I-自蛋白融合干扰素α2b标记率为82.72%,放化纯95.53%,放射性比活度为0.26 MBq/gg;抗病毒活性比较结果表明标记前后的生物学活性几乎无变化;皮下注射大鼠体内分布研究表明,125I-白蛋白融合干扰素α2b在血中于6 h达高峰,消除缓慢,未见特异性组织或器官的浓聚.     

60Co辐照接枝甲基丙烯酸甲酯对竹材力学性能的影响

为研究辐照接枝对竹材力学性能影响,使用60Coγ射线,控制辐照剂量为60-220 kGy,对浸渍甲基丙烯酸甲酯(MMA)单体的毛竹生材和炭化材进行辐射接枝改性.结果显示:浸渍单体的毛竹生材,经180 kGy辐照后,其基本密度、抗弯强度和抗弯弹性模量较原材分别提高了6.7％、4.4％和28％;径向、弦向、体积干缩率分别降...     

球床模块堆停堆后自然对流传热特性数值研究

对冷却流体在球床模块堆内燃料颗粒填充区域中的流动和传热过程进行了研究.数值模拟突然停堆后燃料颗粒区在温差作用下的自然对流过程,分析了瑞利数Ra对燃料填充区域内流场、温度场和局部努塞尔数Nu以及壁面摩擦阻力系数的影响.计算结果表明:当球床模块堆突然停堆时燃料填充区域可形成加热壁面流体上升流动、冷却壁面下降流动的自然循环流动;随着Ra数增大,回流中心向上移动;沿轴向壁面局部Nusselt数和摩擦阻力系数存在极值,并且极值点随Ra数增大而向上移动;与氮气相比,氦气作为冷却介质停堆后具有更均匀的堆芯轴向温度分布.     

Influence of the Gas Mixture Ratio on the Correlations Between the Excimer XeCl Emission and the Sealed Gas Temperature in DIelectric Barrier Discharge Lamps

For dielectric barrier discharge lamps filled with various gas mixture ratios,the correlations between the excimer XeCl emission and the sealed gas temperature have been founded,and a qualitative explication is presented.For gas mixture with chlorine larger than 3%,the emission intensity increases with the sealed gas temperature,while with chlorine about 2%,the emission intensity decreases with the increase in the gas temperature,and could be improved by cooling water .However,if chlorine is less than 1.5% ,the discharge appears to be a mixture mode with filaments distributed in a diffused glow-like discharge,and the UV emission is independent on the gas temperature.     

Numerical study of equilibrium solutions for axisymmetric plasmas with toroidal flow obtained using Solovev approach

Solovev approach of finding equilibrium solutions, which was extended to include the vacuum solutions provided by Zheng, Wooton, and Solano, was found extremely useful for the purpose of shaping studies. Its extension to toroidal equilibria with a general plasma flow was examined theoretically in a companion paper by Chu, Hu and Guo. The only meaningful extension was found for plasmas with a pure toroidal rotation and with a constant Mach number. A set of functions {SOLOVEV_ZWSm} was obtained which fixed location of the magnetic axis for equilibria with quasi-constant current density profile, with toroidal flow at constant Mach number and with specific heat capacity 1. The set {Solovev_ZWSm} should have complete shaping capability for plasma shapes with positive curvature at the boundary; but not for plasmas with negative curvature boundary points, i.e. the doublets or bean shaped tokamaks. We report here extensive numerical studies showing the shaping capability of {Solovev_ZWSm} for plasmas with pure toroidal rotations, including the change in topology of the solution when the rotation mach number changes. Included plasma topology are the sphere (spheromaks); and the tokamaks (including the doublets).