等电子三原子铀化物OUO^(2+)、NUN和NUO^+的结构和谐振频率的CCSD(T)计算研究

用小核相对论有效势和CCSD(T)方法计算了三原子铀化物OUO2+,NUN和NUO+的平衡键长和谐振频率.计算结果显示U原子内层5s5p5d电子相关能对这些化合物性质的影响非常小.除NUN的弯曲振动频率,旋轨耦合效应对这些化合物的结构和频率的影响并不明显.本文的计算结果与其他研究组的计算结果以及已有的实验值相比符合较好,这表明作为单参考态方法,CCSD(T)能够对这些体系的键长和频率给出较精确的计算结果.与此前密度泛函理论(DFT)的计算结果相比,CCSD(T)方法与PBE0泛函的结果吻合最好.本文的工作有助于在用密度泛函方法研究这些体系时选择合适的交换相关泛函,也为今后的实验研究提供了新的理论数据.

火焰原子发射法测定硝酸铀酰中的微量铯

对铀化物中的杂质元素,化学工作者通常是先将铀基体分离掉,然后再用分光光度、原子吸收等方法进行测定。但,迄今我们没有见到用原子吸收分光光度计以FAES为分析手段的测定铀化合物中铯元素的报道。铯的火焰原子吸收法测定,灵敏度较低。欲用加大样品量的方式去适应测定需要,势必给萃取分离带来困难。而具有较高灵敏度的FAES法可以满足测定要求。因铯的电离电位很低(3.95 eV),测定时存在严重的电离效应的不利影响,我们试图加入钾的硝酸盐予以消除;这一尝试终于取得了令人满意的效果。不过,出于对样品测定时信噪比的考虑,鉴于背景发射随钾盐量增加而增大,因而严格控制其钾的加入量是至关重要的。

Really active form of fluorine toxicity affecting Acidithiobacillus ferrooxidans activity in bioleaching uranium

In order to determine the mechanism of bacterial tolerance to fluorine,Acidithiobacillus ferrooxidans ATCC 23270 was domesticated and studied under the conditions of different fluorine concentrations and pH values with or without treatment by Proteinase K.The bacterial activities were observed through measuring the changes of solution potentials by platinum electrode with Ag/AgCl reference electrode and the intracellular fluorine was determined by-uorine ion-selective electrode.The results indicated that the tolerance of Acidithiobacillus ferrooxidans ATCC 23270 to fluorine could be obviously improved by domestication,HF was the effective form of fluorine to affect the bacterial activity,and pH increase or concentration change of ions of strong complex ability with fluorine ions in solution could result in false appearance of high fluorine-resistant strain.Some proteins located in cell wall or cell membrane were intimately relative with the bacterial fluorine tolerance.

Chemical Interaction UO2Cl2 with α-and β-Amino Acids in Aqueous and Organic Solution

This paper presents the results of the search of biologically active uranium compounds such as amino acids. We first received and examined X-ray and IR （infrared radiation） spectroscopy of uranium complexes with α- and β-amino acids in aqueous and organic solution. We proposed a method for direct synthesis of complex organic compounds of uranium chloride UO2Cl2 with α- andβ-amino acids for the synthesis of drugs for the treatment of cancer.

Enhancing recovery of uranium column bioleaching by process optimization and kinetic modeling

This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.

Preparation of Uranyl Complexes with Sugars

We first received and examined X-ray and IR （infra red） spectroscopy of uranium complexes with sugars. We proposed a method for direct synthesis of complex organic compounds, uranium chloride UO2Cl2 with various sugars （D-glucose, D （＋） maltose, D-sucrose, D-lactose and the polysaccharide Dextran） as potential precursors for the treatment of cancer diseases.

Uranyl oxamate hydrates: hydrothermal synthesis, crystal structure, photophysical properties, and selective crystallization

Presented here are two isostructural uranyl coordination polymers [UOe（EDO）（H2O）]· H2O （1） and [UO2（BDO）（H2O）]-2H2O （2） （EDO2---ethylene-1,2-dioxamate; BDO2 =butylene-1,2-dioxamate） with identical stepwise zigzag chain structure and distinct interchain hydrogen bonding interaction, prepared from hydrothermal reaction of DEEDO or DEBDO （DEEDO- diethyl ethylene-1,2-dioxamate; DEBDO--diethyl butylene-l,2-dioxamate） with uranyl ions. The monomeric uranyl-based fluorescence emissions of compounds 1 and 2 are red-shifted by about 6 and 5 nm respectively, compared to that of uranyl nitrate hexahydrate. Compound 1 has stronger emission than compound 2, but both their emissions exhibit triple-exponential decay. The photophysics of uranyl oxalate trihydrate was also investigated for comparison. The selective crystallization of compound 1 in alkaline solution was applied to the sequestration of uranyl ions, showing a kinetic preference.