Liquid-liquid extraction of Pa-233(V) with Aliquat 336

The extraction of protactinium with Aliquat 336 (methyl-tri-caprylyl ammonium chloride) in toluene, cyclohexane and chloroform from HCl, HNO3, H2SO4, HClO4, HF and mixed HCl-HF media was investigated by radioactive tracer technique. Distribution ratios of protactinium between the aqueous solution and the organic phase were determined as a function of shaking time, concentrations of acid in aqueous solution phase, extractant concentration and type of diluents in the organic phase. Aliquat 336 can almost quantitatively extract protactinium from strong HCl solution. At the same time, small amounts of HF in HCl solutions have a strong effect on Pa distribution.

基于GEANT4的CsI(Tl)闪烁体探测器的Monte Carlo模拟；Monte Carlo Simulation of CsI(Tl) Scintillator Detector with GEANT4 ToolKit

对闪烁光在晶体内的传输以及光电子倍增过程进行了建模,基于GEANT4软件包对CsI(T1)闪烁体探测器进行了蒙特卡罗模拟,得到了不同形状、尺寸和包装的CsI(Tl)晶体测量γ射线的能谱。对比模拟和测试结果,两者得到了很好的符合,从而验证了模拟参数的合理性和可靠性。该模拟程序的建立为闪烁体探测器的设计提供了更精确的开发工具。

几种观赏花卉对土壤铅的吸收特性和抗性能力研究

本实验研究花卉在铅污染条件下对铅的吸收特性及其对铅的抗性,积累铅毒害作用资料,为铅污染环境的净化和景观化提供材料。结果表明三种观赏花卉中波斯菊(Cosmos bipinnatus)地上部吸收富集铅的量最大,积累铅能力最强,其次为翠珠花(Trachymene coerulea),香石竹(Dianthus caryophyllus)吸收积累铅能力最弱;根部铅富集量最大的为波斯菊,其次为香石竹,翠珠花根部铅吸收积累能力最弱。在Pb浓度为1 000 mgkg-1时,铅污染可以刺激波斯菊和翠珠花生长,使其根部和地上部的生物量增加,这两种花卉对铅污染的抗性很强,但铅污染会显著抑制香石竹的生长,香石竹对铅污染的抗性很差。

土壤类型和添加有机物料对铵态氮回收的影响

探讨NH4+-N回收率在不同因素下的变化规律。【方法】以黄土高原从北向南不同地区的典型土壤类型为对象,采用Bremner浸取法,研究了土壤类型、植被类型、施肥模式及添加有机物料对铵态氮回收率的影响。【结果】不同类型土壤及不同类型植被间NH4+-N回收率存在极显著差异(P<0.01)。黄土正常新成土的NH4+-N回收率最高(88.8%),极显著大于其他土壤,土垫旱耕人为土的NH4+-N回收率最低(81.0%),简育干润均腐土和干润砂质新成土介于二者之间;不同类型植被间,林地土壤的NH4+-N回收率(91.0%)极显著高于其他类型植被土壤,其他类型植被土壤的NH4+-N回收率表现为农田(85.5%)>裸地(83.8%)>草地(83.6%),但三者之间差异不显著。添加有机物料后,土壤NH4+-N回收率极显著增加(P<0.01),不添加有机物料对照土壤的NH4+-N回收率为84.3%,添加长毛草和苜蓿后的NH4+-N回收率分别为86.6%和85.9%。长期施肥对土壤NH4+-N的回收率无显著影响(P=0.436 5>0.05)。【结论】NH4+-N回收率与粘粒含量呈弱负相关,与有机质含量呈正相关,粘土矿物对N...

有机酸对铅胁迫小麦幼苗部分生理特性的影响

通过对小麦幼苗部分生理指标的分析,研究了外源有机酸(乙酸、草酸和柠檬酸)对铅胁迫小麦幼苗的缓解效应。结果表明:加入3种外源有机酸均能够减轻铅对小麦叶绿素的破坏;低浓度的有机酸能提高受铅胁迫小麦的保护酶(SOD、POD、CAT)的活性,降低MDA含量,但随着外源有机酸处理浓度的增加,缓解作用降低或消失,保护酶活性降低,MDA含量增加。3种有机酸中草酸对铅胁迫的缓解作用最明显。

Method for calculating ecological water storage and ecological water requirement of marsh

As one of the most typical wetlands, marsh plays an important role in hydrological and economic aspects, especially in keeping biological diversity. In this study, the definition and connotation of the ecological water storage of marsh is discussed for the first time, and its distinction and relationship with ecological water requirement are also analyzed. Furthermore, the gist and method of calculating ecological water storage and ecological water requirement have been provided, and Momoge wetland has been given as an example of calculation of the two variables. Ecological water use of marsh can be ascertained according to ecological water storage and ecological water requirement. For reasonably spatial and temporal variation of water storage and rational water resources planning, the suitable quantity of water supply to marsh can be calculated according to the hydrological conditions, ecological demand and actual water resources.

溶剂萃取法制备的纳米CeF_3紫外吸收性能研究

利用Cyanex 923萃取法制备了纳米级CeF3微粉,并研究了分散剂、CeF3量、CeF3预处理灼烧温度和微粉粒径分布等因素对CeF3紫外吸收行为的影响。结果表明,CeF3在255 nm附近有特征吸收峰;分散剂的极性强弱、分散物浓度的改变都会影响吸收峰的强弱;随着粒径的减小,紫外吸收峰发生明显的红移。此外还研究了TiO2包覆CeF3的紫外吸收性质,复合材料在250~400 nm区间内同时出现了TiO2和CeF3的特征吸收峰,复合材料的吸光域范围扩展。

Synthesis, structure and optical properties of new organic-inorganic haloplumbates complexes (C5H10N3)PbX4 (X = Br, Cl), (C2H2N4)PbBr3

Layered organic-inorganic composite materials (C5H10N3)PbX4 (X = Br 1, Cl 2) containing histaminium dications were grown via a solution-cooling process, and their structure and optical properties were determined. The organic ligand-histaminium introduced into the corner-sharing octahedra of the 'PbX4- layer' contains both primary ammonium and imidazolium different from the traditionally primary amine found in this system. As comparison, another analogous amine of 3-amino-1,2,4-triazol was used as ligand to coordinate with PbBr2 in acid solution. A novel complex (C2H2N4)PbBr3 (3) was obtained with zigzag PbBr2 chains different from the PbX4 layer in compound as 1 and 2. The hybrid (C5H10N3)PbX4 show exciton absorption at 339 nm for X = Cl and 419 nm for X = Br with the corresponding emission at 360 and 436 nm, respectively. The different PbBr2 chain structure of compound 3 does not show photo luminescence.