Weak acid leaching of uranium ore from a high carbonate uranium deposit

Journal of Radioanalytical and Nuclear Chemistry - Mineralogical study showed that the Yuejin uranium ore is from a low grade, high carbonate and high pyrite sandstone type uranium deposit. Uranium...     

[Cu(en)_2]~(2+)修饰的二维仲钨酸化合物:[{Na_3(H_2O)_(10)}_2H_2{Cu(en)_2(H_2W_(12)O_(42))}]·16H_2O(英文)

利用水热合成法制备了一种基于[Cu(en)2]2+修饰的仲钨酸化合物:[{Na3(H2O)10}2H2{Cu(en)2(H2W12O42)}].16H2O(en=乙二胺)(1),借助元素分析、X射线单晶衍射分析I、R、UV、热分析和X射线光电子能谱对这种化合物进行了结构和性质研究.化合物(1)属于三斜晶系,P-1空间群.晶胞参数为:a=1.183 2(5)nm,b=1.296 0(6)nm,c=1.416 9(6)nm,α=63.348 0(10)°,β=82.844 0(10)°,γ=68.907 0(10)°,V=1.810 0(14)nm3,Z=1,R1[I2σ(I)]=0.024 7,wR2[I2σ(I)]=0.058 2.化合物(1)通过仲钨酸阴离子,铜离子和[Na3(H2O)10]3+三核簇形成了新型的二维层状结构.     

Interface dominated high photocatalytic properties of electrostatic self-assembled Ag(2)O/TiO(2) heterostructure

Electrostatic self-assembled Ag(2)O/TiO(2) nanobelts heterostructure was synthesized via simple physical mixing of Ag(2)O nanoparticles and TiO(2) nanobelts. The morphologies and microstructures of Ag(2)O/TiO(2) nanobelt heterostructure were characterized by high resolution transmission electron microscopy. The interface dominated high UV photocatalytic activity and degraded photoluminescence strength of composite catalyst confirmed the heterostructure effect between Ag(2)O nanoparticles and TiO(2) nanobelts. X-ray photoelectron spectroscope provided direct evidence of charge transfer on the heterostructures between them.     

A sidelobe suppression method with experiment for underwater acoustic imaging

In this paper,a sidelobe suppression method using nonuniformly spaced array with aperture apodization processing is proposed for underwater acoustic imaging in near field,which is studied both in theory and experiment.The focused beamforming based on spherical wave propagation theory is used in the method.Firstly,the nonuniform array with low sidelobe is designed for suppressing the sidelobe of one-way beam pattern by spacing perturbation.Then, applying the aperture apodization technique to underwater acoustic imaging,the different size apertures for transmitting and receiving are used for further suppressing the sidelobe of two-way beam pattern.The experimental results from water tank show that the proposed method can suppress the sidelobe more effectively only with fractional mainlobe width increase.Since the method is simple-realized,the imaging system can be simplified as well as achieving improved performance.     

垂直磁场中超导薄膜上的涡旋涨落

本文用二维非中性库仑气体模型描述磁场中超导薄膜上的涡旋涨落,将中性库仑气体的自洽方程组推广到非中性模型,并求得其数值解．文中着重讨论了非中性模型电荷配对的渡越行为和再入现象     

壳聚糖-两性聚氨酯接枝共聚物的制备

利用壳聚糖大分子链上的－OH和－NH2基团与两性聚氨酯预聚体的端－NCO基团反应，把两性聚氨酯链接枝到壳聚糖分子链上，为聚电解质及纳米胶体粒子间的组装，复合性质的研究提供模型化合物，红外光谱，热分析方法初步研究表明，采用上述方法能够制备出APU－壳聚糖接枝共聚物，但产物是壳聚糖与接枝共聚物的混合物，研究发现，这种接枝共聚物在盐酸水溶液中呈胶束形态，而且具有独特的流变性。     

Synthesis of novel 2-azabicyclo[2.2.0]- and [2.1.1]hexanols

Methyl- and phenyl-substituted N-(ethoxycarbonyl)-2-azabicyclo[2.2.0]hex-5-enes 6 were reacted with NBS in wet DMSO to afford bromohydrins. Mixtures of unrearranged 6-exo-bromo-5-endo-hydroxy-2-azabicyclo[2.2.0]hexanes 7a,b and rearranged 5-anti-bromo-6-anti-hydroxy-2-azabicyclo[2.1.1]hexanes 8a,b were formed stereoselectively from the parent alkene 6a and 4-methyl alkene 6b. The 5-methyl alkene 6c affords only unrearranged bromohydrin 7c and dibromohydrin 9. By contrast, solely rearranged 3-endo-substituted-2-azabicyclo[2.1.1]hexane bromohydrins 8d-f result from additions to 3-endo-methyl alkene 6d, 3-endo-4-dimethyl alkene 6e, and 3-endo-phenyl alkene 6f. As an alternative route to bromohydrins, the parent 5,6-exo-epoxide 10a and 5-endo-methyl-5,6-exo-epoxide 10b were ring opened with bromine/triphenylphosphine to afford unrearranged 5-endo-bromo-6-exo-hydroxy-2-azabicyclo[2.2.0]hexanes 11a,b, while the 3-endo-methyl epoxide 10c afforded solely the rearranged 5-anti-bromo-6-anti-hydroxy-3-exo-methyl-2-azabicyclo[2.1.1]hexane isomer 8g. Tributyltin hydride reduction of bromohydrins 7a,b and 11a afforded novel 2-azabicyclo[2.2.0]hexan-5-ols 13a,b and -6-ol 14, and bromohydrins 8a,b, 8d-g afforded new 2-azabicyclo[2.1.1]-hexan-5-ols 15a,b and 15d-g.     

Poly[[[tri(urea‐κO)manganese(II)]‐μ‐thiocyanato‐κ2N:S‐mercury(II)]‐tri‐μ‐tetrathiocyanato]

The title complex, [MnHg(SCN)₄(CH₄N₂O)₃]_n, consists of slightly distorted octahedral MnN₃O₃ and tetrahedral HgS₄ units. The Mn^II atom is coordinated by the O atoms of three urea mol­ecules and by the N atoms of three SCN^? ions; Hg^II is coordinated by four S atoms from SCN^? ions. Each pair of Mn^II and Hg^II atoms is connected by an –SCN– bridge, forming infinite two‐dimensional –Mn—NCS—Hg– networks.