脉冲中子、伽马探测系统性能表征与设计技术

探测系统是获取辐射场特征信息的核心器件，是实施脉冲辐射探测的关键和技术基础，其性能直接决定测试数据的质量和测试方法的选择。对影响脉冲辐射探测的性能指标进行系统描述、表征是探测系统设计、研制、实际应用和综合性能评价的基础。用于复杂能谱脉冲中子、伽马混合辐射场时间谱、强度谱测量的探测系统，主要性能包括探测灵敏度、时间响应、能量响应、线性电流和中子、伽马分辨能力等指标参数，这些参数的获得与实现，需要根据中子、伽马射线与物质相互作用的基本原理，构建相应的探测结构和技术原理。在设计上，综合权衡能量收集和电荷收集方式选择、几何效率完备和高信噪比结合、信号响应和直照响应分离、探测效率与时间特性兼顾、综合性能与使用可靠性一致等设计原则，综合应用这些原则构成了探测系统设计方法。     

微波辐射法合成L-聚乳酸

通过微波辐射,以L-乳酸为原料、SnCl2为催化剂、季戊四醇为引发剂,在负压和氮气保护条件下合成了具有直链和星形结构的L-聚乳酸.产物黏均分子量和玻璃化温度均较高.发现了氮气流量的大小对合成产物颜色的影响较大,当氮气流量较大时产物白度大,氮气流量小时产物白度小,优化了合成条件.并用FTIR1、3C NMR对产物进行了结构表征.利用GPC、DSC和MDA对产物进行了分析,分析结果显示星形结构的L-聚乳酸具有应变小、受力后外形恢复快等特点,比直链结构的L-聚乳酸更适合作医学骨质替代物.     

Effect of wortmannin and 3-AB on G2 phase arrest and transient failure to activate MPF induced by ionizing irradiation

Active mitosis promoting factor (MPF) composed of p34 cdc2 with cyclin B1 is required for the cell cycle transition from G 2 to M phase. Recent studies have demonstrated that ionizing radiation (IR) exposures associated with inhibition of p34 cdc2 activity was the mechanism of G 2 arrest. At low dose, IR causes transient failure to dephosphorylate p34 cdc2 instead of suppression of cyclin B or MPF formation of cyclin B with p34 cdc2 complex. But the signaling events that regulate p34 cdc2 in irradiated cells remain unclear. This note demonstrates that PI3 kinase family inhibitor wortmannin (wort) and PARP specific inhibitor 3_AB can reduce the G 2 arrest induced by 2Gy γ_ray. Immunoprecipitation studies demonstrate that wort and 3_AB can facilitate dephosphorylation of p34 cdc2 in G 2 phase arrest induced by radiation. These findings suggest that wort sensitive pathway and PARP may be involved in initiating the signal transduction of G 2 phase arrest caused by IR.     

环绕光子晶体微带贴片天线衬底厚度影响分析

以有限元法模拟一种环绕光子晶体的微带贴片天线,解出与理论结果有极好吻合的谐振频率后并进一步求解辐射性能,与常规微带贴片天线相比较证实了这种贴片天线能够抑制表面波,提高辐射增益,再改变天线衬底厚度进行仿真并讨论反射系数和辐射方向图的变化.     

稳态轴对称Sen黑洞的量子效应

借助乌龟坐标，得到了在稳态轴对称Ｓｅｎ黑洞视界附近的Ｋｌｅｉｎ－Ｇｏｒｄｏｎ方程的解，导出了Ｈａｗｋｉｎｇ热谱公式。通过与一般Ｅｉｎｓｔｅｉｎ黑洞比较，发现ｄｉｌａｔｏｎ场对黑洞的热力学性质有很大的影响。     

（1＋1）维准静态时空的热辐射

研究了一种（１＋１）维准静态时空的热辐射。在动态情况下，每一准静态事件的视界分裂为两个，且有一稳态事件界处在相应的两个动态局部事件视界之间。因此，采用广义Ｔｏｒｔｏｉｓｅ坐标变换和解析延拓，得到了这种时空的热辐射温度。     

2-Steps Preparation Activated Carbon from Solidago Canadensis: Carbonized by Electrial heating and Activated by Microwave Radiation

The activated carbon(AC)was prepared from Solidago Canadensis(SC),an alien invasive plant.The plant was firstly carbonized under nitrogen at 400 ℃ for 90 min in an electrical furnace,and then the carbonized product was activated with KOH through microwave radiation.Effects of KOH/C ratio,microwave power,microwave radiation time on the adsorption capacities and yield of AC were evaluated.It indicated that the optimum conditions were KOH/C ratio 2 g/g,microwave power 700 W,and microwave radiation time 6 min.The carbonation process of SC was analyzed by thermogravimetry(TG).The pore structural parameters and surface functional groups of the AC were characterized by nitrogen adsorption-desorption and Fourier Transformed Infrared Spectroscopy(FTIR),respectively.The activation yield,the surface area,the average pore size,and the average micropore size of AC prepared from optimum conditions were 53.75%,1 888 m2/g,0.567 nm,and 0.488 nm,respectively.The adsorption amounts of AC were 302.4 mg/g for methylene blue and 1 470.27 mg/g for iodine.     

Rendering Grass Blowing in the Wind with Global Illumination

We have simulated a time varying wind field using the lattice Boltzmann model, and its effect on blades of grass with a simple mass-spring model. We present a global illumination model for multiple scattering of incident sun and sky illumination within the field of grass. We model the grass as a continuous distribution of infinitesimal colored scattering flakes and solve a system of differential equations for the radiance transport. We repeat this for a collection of grass bending directions and amounts, an...     

空间光通信用耐辐照掺铒/铒镱共掺光纤研究进展

掺铒和铒镱共掺光纤放大器具有抗电磁干扰、紧凑轻质、电光转换效率高、免调试维护等优势，在空间光通信系统中发挥着重要作用.然而，当光纤放大器长时间暴露在地球空间轨道恶劣的辐照环境中时，会受到宇宙中带电粒子和高能电磁辐射的综合作用，尤其是增益光纤在辐照环境会引起辐照损伤导致激光放大性能失效，严重制约它在空间光通信领域的应用.该文简要介绍了太空辐照环境中辐照导致光纤性能下降的现象与问题，然后从辐照效应的产生机理、影响光纤耐辐照性能的因素、辐照加固方法三方面详细阐述了耐辐照掺铒和铒镱共掺光纤的研究进展，最后对其未来的研究趋势进行了展望.     

睾酮衍生物ATES对6.5 Gy 60Co γ射线辐射C57小鼠外周血血象影响

研究旨在利用C57小鼠60Coγ射线辐照模型,观察睾酮衍生物ATES对小鼠照射后外周血血象的影响。48只C57小鼠经6.5 Gy60Coγ射线全身1次照射后建立骨髓型急性放射病动物模型。模型动物被随机分为照射对照组、单次给药组、照后连续n次给药组(n=2、3、4、5),每组8只。单次给药组于照射后2 h皮下注射ATES 10 mg/kg;连续给药组分别于照射后2 h和照后n d内每天一次皮下注射ATES 10 mg/kg;照射对照组于皮下注射同样体积的空白辅剂。观察照射前后小鼠外周血象变化与药物对体重的影响。与照射对照组相比较,ATES治疗能明显促进外周血白细胞数、中性粒细胞数、红细胞数、血红蛋白水平、血小板数以及单核细胞数的恢复。结论:ATES可以明显促进急性放射病小鼠的造血功能恢复,为研究临床治疗急性放射病提供实验依据。