日常生活的电磁辐射与生物效应

本文简单介绍了电磁辐射和生物效应的原理和现象以及相关的研究情况和标准.包括:电磁辐射对机体的影响,电磁辐射对人体影响的研究情况,行业的卫生标准和生活中与电磁辐射接触的机会.     

浓缩硼同位素的化学提纯与质谱分析

一、引言 在核燃料循环中,准确地测定硼同位素丰度及确定核燃料产品中硼含量具有重要意义。 关于硼的化学提纯方法有蒸馏法、萃取法,离子交换法,汞阴极电解法等,其中蒸馏法能使硼与其他杂质元素分离比较完全,而且,操作简便、重复性好、适应范围广。本工作用蒸馏法提纯浓缩硼元素获得了比较满意的结果。     

Degradation of Alizarin Red by Hybrid Gas-Liquid Dielectric Barrier Discharge

A system based on dielectric barrier discharge （DBD） with improved discharge sta- bility and homogeneity was used for the degradation of Alizarin Red （AR）. This special structure of the DBD system is characterized by the high voltage electrode, which is covered with a quartz tube and partially immersed in water, and by directly using the water as the ground electrode. A transition was realized from the filamentary mode for the conventional structure of the DBD to the semi-homogeneous mode for such a configuration of the plasma discharge. The spectra of plasma are dominated by N2 molecular lines in the ultraviolet-A radiation region. Plasma degra- dation of AR in this system exhibited pseudo-first-order reaction kinetics. The degradation rate of AR reached 95% or so after 14 min treatment under favorable conditions. Alkaline conditions are favorable for the degradation of AR. The increase of conductivity of the solution, input power and usage of oxygen bubbling could enhance AR degradation.     

脉宽调制器单粒子效应测试系统研制

本文在分析脉宽调制器(PWM)单粒子效应主要失效模式的基础上,研制了具备频率异常测试、占空比异常测试和参考电压测试功能的PWM单粒子效应测试系统,并在中国原子能科学研究院HI-13串列加速器上开展了单粒子效应试验。试验结果表明:单粒子效应会导致PWM输出信号的脉冲丢失和占空比改变,脉冲丢失时间和占空比改变的持续时间有时可达数ms;UC1825AJ型PWM的单粒子效应LET阈值约为4.4MeV·cm2·mg-1,UC1845AJ型PWM的抗单粒子性能受工艺批次的影响较大。     

结晶器漏钢预报系统

对连铸机结晶器漏钢预报系统的控制原理,功能,结构进行了说明,该系统对提高连铸机作业率具有重要意义。     

镧对汞胁迫下豌豆(Pisum sativum L)幼苗生长及汞积累的影响

以培养 5d的豌豆 (PisumsativumL)幼苗为实验材料 ,研究了 10和 5 0mg·L- 1 的Hg胁迫下不同浓度La对豌豆幼苗生长的生理效应 ,测定并分析了La对Hg胁迫下豌豆幼苗根和叶细胞中Hg吸收及积累的影响。结果表明 ,合适浓度 (≤ 0 .0 10mg·L- 1 La)的La能在一定程度上缓解Hg胁迫所导致的叶绿体叶绿素和可溶性蛋白含量、光合速率和叶绿体Mg2 ATPase、光合膜电子传递链活性及PSII活性的降低 ,减轻Hg胁迫对光合膜室温下吸收光谱和荧光光谱的影响 ;能有效增强或保护Hg胁迫下叶片细胞总抗氧化能力 ,降低细胞内Hg胁迫诱导超氧阴离子(·O2 - )产生的速率和膜脂过氧化产物 (MDA)的积累 ,延缓膜透性的增加。La对 10mg·L- 1 Hg胁迫的缓解能力较强 ,而对 5 0mg·L- 1 Hg的缓解效果较弱。最佳作用浓度为 0 .0 10mg·L- 1 。该浓度的La能有效的减少细胞对Hg的吸收和积累 ,特别是增加根细胞壁对Hg的束缚效应。超过一定浓度范围的La(≥ 0 .0 3 0mg·L- 1 )则加剧Hg的毒害作用。     

浅谈英语口语教学的影响因素

针对当前大学英语口语教学效果不够理想的现状,探讨了影响英语口语教学的几个主要因素,并指出合理地利用这些因素可以有效促进英语口语的课堂教学效果.     

常见蔬菜消除超氧阴离子作用的研究

用核黄素光化学氧化光度法研究了南瓜、玉米、大蒜、苦瓜、空心菜、西红柿、胡萝卜、韭菜花8种常见蔬菜对超氧阴离子的消除作用。结果表明这些蔬菜均具有消除超氧阴离子的作用;煮沸20min,玉米和南瓜的消除超氧阴离子能力减弱约30％,空心菜的有所上升,而大蒜、苦瓜、西红柿、胡萝卜、韭菜花的消除作用均没有变化。将吸光度随这八种蔬菜提取液加入量的变化趋势与维生素C的相比较,提出蔬菜消除超氧阴离子的作用主要是依靠维生系C以外的超氧化物歧化酶等物质。     

基于径向基函数的区域地磁场边界插值约束

针对区域地磁场模型存在的边界效应问题,采用基于径向基函数的插值方法,对缺少测量点的边界区域进行插值约束。在某海区地磁场建模仿真试验中,利用该方法结合有限区域的地磁观测数据,得到了边界区域地磁场的插值结果,并建立了海区地磁场模型。建模结果表明,该方法较补充国际地磁参考场值的方法,具有更高的分辨率和更小的均方偏差,为提高模型精度、改善边界效应提供了有效途径。     

Isolation of Leptospirillum ferriphilum by single-layered solid medium

According to physiological and biochemical characteristics of Leptospirillum ferriphilum,a strain of object bacteria was isolated successfully.Bacteria were enriched by selective liquid medium and plated on designed single-layered agar solid medium.Colony was cultured and bacteria were collected.The morphologies of the object bacteria were observed using crystal violet staining,scanning electron microscope(SEM)and transmission electron microscope(TEM).The result of 16S rDNA identification shows that this bacterium belongs to Leptospirillum ferriphilum and it is named as Leptospirillum ferriphilum strain D1.These results indicate that this new single-layered agar solid medium is efficient and simple for isolation of Leptospirillum ferriphilum.Additionally,physiological-biochemical characteristics show that the optimum initial pH value and its growth temperature are 1.68 and 40 ℃,respectively.The culture of it is used to leach a complex concentrate chalcopyrite,the leaching efficiencies of copper and iron are 1.93 % and 13.74 %,respectively,and it is more effective than the A.ferrooxidans culture in the leaching of the complex concentrate chalcopyrite.