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151.
组合式Si-PIN 14 MeV中子探测器   总被引:4,自引:0,他引:4       下载免费PDF全文
提出了一种在多片Si-PIN探测器中间用2mm厚的聚乙烯作为灵敏度增强介质,采用加法电路模式进行信号输出的组合式新型DT聚变中子(14MeV)探测技术原理. 这种组合的主要特点有: 1)大幅度提高了Si-PIN探测器的中子灵敏度和测量统计性; 2)提高了探测器的n/γ分辨本领; 3)在实现多个探测器信号相加的同时,组合探测器相对于单片探测器时间响应没有明显改变. 从实验及理论上对组合探测器的14MeV中子及1.25MeV γ灵敏度、n/γ分辨,时间特性和测量统计性进行了研究. 关键词: Si-PIN半导体探测器 灵敏度 n/γ分辨 时间响应  相似文献   
152.
Gd2O3:Eu3+纳米晶的燃烧合成及光致发光性质   总被引:4,自引:0,他引:4       下载免费PDF全文
采用柠檬酸作燃烧剂用燃烧合成法制备了Gd2O3:Eu3+纳米晶.用X射线衍射仪(XRD)、高分辨透射电子显微镜(HRTEM)和荧光分光光度计等对Gd2O3:Eu3+纳米晶的结构、形貌和发光性能进行了分析.结果表明:不同柠檬酸与稀土离子配比(C/M)制备的样品经800℃退火1 h后,均得到了纯立方相的Gd2O3:Eu3+纳米晶,晶粒尺寸约为30 nm,尺寸分布较窄,其中以C/M=1.0时制备的纳米晶结晶性最好,发光强度最大.Gd2O3:Eu3+纳米晶主发射峰位置均在612 nm处(5D0→7F2跃迁),激发光谱中电荷迁移态发生红移,观察到Gd3+向Eu3+的有效能量传递.对柠檬酸与稀土离子配比(C/M)对结晶度、发光性质等的影响也进行了分析和讨论.  相似文献   
153.
We make a mapping from Sierpinski fractals to a new class of networks, the incompatibility networks, which are scale-free, small-world, disassortative, and maximal planar graphs. Some relevant characteristics of the networks such as degree distribution, clustering coefficient, average path length, and degree correlations are computed analytically and found to be peculiarly rich. The method of network representation can be applied to some real-life systems making it possible to study the complexity of real networked systems within the framework of complex network theory.  相似文献   
154.
Low surface energy polymer thin-films can be applied to surfaces to increase hydrophobicity and reduce friction for a variety of applications. However, wear of these thin films, resulting from repetitive rubbing against another surface, is of great concern. In this study, we show that highly hydrophobic surfaces with persistent abrasion resistance can be fabricated by depositing fluorinated carbon thin films on sandblasted glass surfaces. In our study, fluorinated carbon thin films were deposited on sandblasted and as-received smooth glass using deep reactive ion etching equipment by only activating the passivation step. The surfaces of the samples were then rubbed with FibrMet abrasive papers in a reciprocating motion using an automatic friction abrasion analyzer. During the rubbing, the static and kinetic friction forces were also measured. The surface wetting properties were then characterized using a video-based contact angle measuring system to determine the changes in water contact angle as a result of rubbing. Assessment of the wear properties of the thin films was based on the changes in the water contact angles of the coated surfaces after repetitive rubbing. It was found that, for sandblasted glass coated with fluorinated carbon film, the water contact angle remained constant throughout the entire rubbing process, contrary to the smooth glass coated with fluorinated carbon film which showed a drastic decrease in water contact angle with the increasing number of rubbing cycles. In addition, the static and kinetic friction coefficients of the sandblasted glass were also much lower than those of the smooth glass.  相似文献   
155.
 建立了谱线增益系数与温度、粒子数分布之间及谱线增益系数与谱线强度之间的关系式,对一台燃烧驱动DF激光器的发射光谱进行了测量,利用发射光谱数据计算得到光腔温度为381.4 K,分布在振动态能级1与0,振动能级2与1,振动能级3与2的粒子数之比分别为0.60~0.62, 0.676 4, 0.71~0.74。  相似文献   
156.
紧凑型X-pinch装置探头标定   总被引:3,自引:0,他引:3       下载免费PDF全文
 介绍了紧凑型X-pinch脉冲功率装置的电流电压测量设计方法。根据该装置的同轴传输线结构特点,研制了一种利用金属膜连接传输线外筒与负载外筒,构成回路测量负载电流的探头。在传输线末端设计电容分压器作为测量负载电压的探头,并利用电路模拟软件对此过程进行模拟,同时这两个探头需要进行在线标定。实验研究结果表明,该探头性能稳定、响应快,是测量负载电流与电压的理想工具。  相似文献   
157.
The excess weight loss due to the evaporation of zinc compound is observed in the growth of ZnO film by trifluoroacetate metalorganic deposition (TFA-MOD) method. Higher temperature (>90 °C) aging and/or addition of monoethanolamine (MEA) are effective to prevent the evaporation of zinc compound and increase the yield of ZnO. The mechanism of preventing evaporation is that zinc trifluoroacetate is hydrolyzed into Zn4O(CF3COO)6. A three-dimensional structure of Zn4O(CF3COO)6 is proposed. It is shown that higher temperature aging does harm to the surface morphology of ZnO films. The addition of MEA reduces the required aging temperature thus improves the surface morphology.  相似文献   
158.
陶汝茂  司磊  马阎星  邹永超  周朴 《中国物理 B》2011,20(9):94208-094208
The propagation performance of high-power partially coherent fibre laser beams in a real environment is investigated and the theoretical model of a high-power fibre laser propagating in a real environment is established. The influence of a collimating system and thermal blooming is considered together with atmospheric turbulence and mechanical jitter. The laser energy concentration of partially coherent beams in the far field is calculated and analysed based on the theoretical model. It is shown that the propagation performance of partially coherent beams depends on the collimating system, atmospheric turbulence, mechanical jitter and thermal blooming. The propagation performance of partially coherent beams and fully coherent beams is studied and the results show that partially coherent beams are less sensitive to the influence of thermal blooming, which results in that the energy degeneration for partially coherent beams is only 50% of that for fully coherent beams. Both partially coherent beams and fully coherent beams become less sensitive to thermal blooming when the average structural constant of the refraction index fluctuations increases to 1.7 × 10-14 m-2/3. The investigation presents a reference for applications of a high-power fibre laser system.  相似文献   
159.
研究了光纤激光阵列目标在回路自适应光学系统在实际大气环境中的传输.从光纤激光阵列、激光在大气中的传输、目标和优化算法四个方面,建立了光纤激光阵列目标在回路自适应光学系统的理论模型.在不同强度大气湍流下,对系统补偿大气湍流影响的效果进行了研究,并对系统控制参数优化进行了简单探讨.结果表明,目标在回路闭环控制结构能够有效补...  相似文献   
160.
在实验研究了As2S8和掺杂As2S8薄膜波导光阻断效应的基础上,讨论了反常电子组态的形成机理和转移机理,提出了光阻断效应切断过程和回复过程的动力学模型,数值分析结果与实验数据十分符合,理论预期与实验现象一致,表明该模型抓住了光阻断效应的基本特征,揭示了过程本质,反映了实验现象的内在机理. 关键词: 光波导技术 硫属化合物玻璃 光阻断效应 动力学模型  相似文献   
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