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91.
在萃取研究过程中,合成了10种由四溴(或碘)合铟(Ⅲ)配阴离子与苯并-15-冠-5或二苯并-18-冠-6合钾(或钠)配阳离子相结合所形成的新型固体配合物。经元素分析、红外光谱及差热-热重等方法对配合物进行了表征。通过与相应的冠醚碱金属苦味酸盐配合物结构性质的对比,较合理地解释了这两类萃取体系之间存在的某些差别。 相似文献
92.
头发铅含量测定的应用价值评价 总被引:1,自引:4,他引:1
调查了125例2-5岁儿童铅中毒状况,测定其全血铅含量和头发铅含量,以全血铅含量为标准,应用诊断试验评价方法评价头发铅测定的应用价值。结果表明,该试验的灵敏度可达88.3%,应用串联试验,即同时测定头发中锌、铁、钙含量,可将该试验的特异度提高至81.8%,阳性预测值达69.6%,阴性预测值达78.8%。 相似文献
93.
94.
Synthesis and Structure of the First Ternary Lead(II) Copper(I) Oxide: PbCu2O2 PbCu2O2 can be prepared by solid state reaction or by precipitation from a basic aqueous solution. Single crystals of the new compound were prepared by recrystallisation from a molten mixture (PbO? Cu2O) and investigated by X-ray diffractometer technique. PbCu2O2 crystallizes isotypically with the homologue silver compound PbAg2O2 (monoclinic with a = 8.223 Å, b = 8.289 Å, c = 6.015 Å, β = 132.62°, Z = 4, space group C? C 1 2/c 1). The crystallographic data from the X-ray investigation are reported. The structure is built by endless [PbO4/4]- and [CuO2/4]-chains. Pb2+ has a one-sided asymmetric coordination with four next oxygen neighbours and Cu+ forms a stretched dumbbell with two oxygen atoms. 相似文献
95.
Rodová M. Brožek J. Knížek K. Nitsch K. 《Journal of Thermal Analysis and Calorimetry》2003,71(2):667-673
Phase transitions in ternary caesium lead bromide (CsPbBr3) were studied by means of DSC, TMA and high temperature X-ray diffraction. The samples were prepared from the solution by
water evaporation and from the melt. on the DSC curves as well as on the temperature dependence of the lattice constants of
CsPbBr3 only two effects were found belonging to the earlier published phase transitions at 88 and 130°C and no further effects.
Linear thermal expansion coefficient α of individual CsPbBr3 modifications were calculated from both TMA and high temperature X-ray diffraction. The structural parameters of the room
temperature orthorhombic phase were refined and the results are presented. CsPbBr3 prepared from the solution contained about 10% of CsPb2Br5 and so the DSC curve of pure CsPb2Br5 was also measured and an effect at a temperature of 68.5°C was found.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
96.
B. G. Bazarov R. F. Klevtsova A. E. Sarapulova K. N. Fedorov L. A. Glinskaya Zh. G. Bazarova 《Journal of Structural Chemistry》2005,46(4):756-760
Single crystals of triple molybdate of composition 5:1:3 K5Pb0.5Hf1.5(MoO4)6 have been grown and their crystal structure has been solved from X-ray diffraction data (an automated diffractometer X8 APEX, MoK α -radiation, 2173 F(hkl), R = 0.0321). Trigonal unit cell parameters are: a = b = 10.739(2) Å, c = 37.933(9) Å; V = 3789(1) Å3, Z = 6, ρcalc = 4.014 g/cm3, space group \(R\bar 3\). Three-dimensional mixed framework of the structure is formed by two types of MoO4 tetrahedra and Pb and Hf octahedra linking via common O-vertices. Potassium atoms of three types occupy large vacancies in the framework. 相似文献
97.
CHEN Wen-Tong GUO Guo-Cong ZENG Xi-Rui LI Xin-Fa FANG Xiao-Niu KUANG Han-Mao LIU Dong-Sheng LIU Li-Min 《结构化学》2007,26(10)
The title compound (4,4'-H2bipy)[CdBr4]·H2O 1 has been synthesized via hydrothermal reaction and characterized by X-ray diffraction. The crystal belongs to monoelinic,space group P21/c with a=8.260(3), b=23.926(7), c=9.774(2) (A), β=106.777(9)°,C10H12Br4CdN2O, Mr=608.26, V=1849.4(9)(A)3, Z=4, Dc=2.185 g/cm3, S=1.005, μ(MoKα)=9.814 mm-1, F(000)=1128, R=0.0646 and wR=0.0989. The crystal structure analysis of 1reveals that the title compound features an isolated structure, based on discrete 4,4'-H2bipy moieties and lattice water molecules which are linked by hydrogen bonds together with tetrahedral cadmium atoms terminally coordinated by four bromine atoms. 相似文献
98.
Huifang Xu Wei Wei Chengliang Zhang Shujiang Ding Xiaozhong Qu Dr. Jiguang Liu Dr. Yunfeng Lu Prof. Zhenzhong Yang Prof. 《化学:亚洲杂志》2007,2(7):828-836
This report presents a facile approach for the low‐temperature synthesis of crystalline inorganic‐oxide composite hollow spheres by employing the bulk controlled synthesis of inorganic‐oxide nanocrystals with polymer spheres as templates. The sulfonated polystyrene gel layer can adsorb the target precursor and induce inorganic nanocrystals to grow on the template in situ. The crystalline phase and morphology of the composite shell is tunable. By simply adjusting the acidity of the titania sol, crystalline titania composite hollow spheres with tunable crystalline phases of anatase, rutile, or a mixture of both were achieved. The approach is general and has been extended to synthesize the representative perovskite oxide (barium and strontium titanate) composite hollow spheres. The traditional thermal treatment for crystallite transformation is not required, thus intact shells can be guaranteed. The combination of oxide properties such as high refractive index, high dielectric constant, and catalytic ability with the cavity of the hollow spheres is promising for applications such as opacifiers, photonic crystals, high‐κ‐gate dielectrics, and photocatalysis. 相似文献
99.
Gino Morisi Marina Patriarca Ferdinando Chiodo Anna Minoprio Antonio Menditto 《Mikrochimica acta》1996,123(1-4):281-290
Between 1992 and 1994, a new screening campaign for blood Pb monitoring in the Italian general population was carried out. Since the first campaign (started in 1978, in accomplishment of the European Community Directive 77/312/EEC) a working group of the Laboratory of Clinical Biochemistry at the Italian National Institute of Health (Istituto Superiore di Sanità), as the Reference Centre (RC), has coordinated the activity of various laboratories spread over the national territory. Appropriate quality assurance procedures, including an external quality assessment scheme (EQAS), were elaborated. Within the EQAS, three or four trials were carried out every year. Each laboratory participating in the trial analyzed eight control samples prepared from cow blood at different Pb concentrations. The results obtained by each peripheral laboratory and the RC between 1992 and 1994 have been compared by regression analysis. The same statistical method was adopted to compare the results obtained by each peripheral laboratory and the RC in the duplicate analysis of about 10 per cent of the human samples collected during the 1992–1994 monitoring campaign. There was no evidence of systematic differences between the regression lines obtained on control and human samples. In spite of the lower Pb concentration in the control samples analyzed during the 1992–1994 campaign, the analytical performance of the laboratories was better than that obtained in the previous screening campaign (1985–1986). Blood Pb levels observed in human samples collected between 1992 and 1994, confirm the downward time trend observed in the campaigns carried out in 1978–1979, 1980–1981 and 1985–1986. This study confirms that the results obtained in an EQAS are representative of the actual performance in the analysis of real (human) samples. 相似文献
100.
Alexander Y. Nazarenko John D. Lamb 《Journal of inclusion phenomena and macrocyclic chemistry》1997,29(3-4):247-258
New polymer inclusion membranes (PIMs) containing 18-membered crownethers and dialkylnaphthalenesulfonic acid are proposed for Sr2+ and Pb2+removal from nitric acid solutions. The influence of source phasecomposition and stripping agents was characterized and permeabilitycoefficients were calculated. The PIMs are easy to prepare and may be usefulin separation and concentration procedures for these cations from complexmixtures such as nuclear waste. Long-term stability was obtained for atleast several weeks of constant use during which no significant change ofpermeability was observed. 相似文献