光泽精与钨（Ⅲ）的流动注射－胶束增敏化学发光反应

采用了Jones柱在线还原钨（Ⅵ）为钨（Ⅲ），详细研究了钨（Ⅲ）与光泽精的化学发光反应，加入乳化剂OP能明显提高发光的信噪比，基于此建立了痕量钨的流动注射化学发光分析法。该法线性范围为1×10－6～1×10－2 g·L－1, 检出限为5×10－7 g·L－1 , 相对标准偏差为2.0％（5×10－5 g·L－1, n=11）。文中还探讨了反应机理。     

Synthesis and Isolation of Diastereomers of Optically Active Cyclomercurated Ferrocenylimines

IntroductionOrganomercurials have been used extensively in organic synthesis and synthesis of other organometallics due to their ability to accommodate practically all the important organic functional groups and their ease in undergoing transmetallation for syntheses of transition metal organometallics which are very useful in organic synthesis. Recently, we reported the synthesis of optically active 1,2-disubstituted cyclomercurated ferrocenylimines by transmetallation reaction of planar chir…     

Kinetic study of acrylamide radical polymerization initiated by the horseradish peroxidase–mediated system

The polymerization kinetics of acrylamide (AAM) in water initiated by a ternary enzymatic system of horseradish peroxidase (HRP)/H₂O₂/acetylacetone (ACAC) was investigated. Conversion–time plots were obtained by dilatometry under different conditions of reaction temperatures and initial concentrations of HRP, ACAC, H₂O₂, and AAM. The results showed that the effect of the initial concentration of ACAC on the inhibition period was significant. The inhibition period decreases with increasing the initial concentration of ACAC. The inhibition period can be even eliminated by the use of a comparatively large amount of ACAC. From the conversion–time plots, the polymerization rate equation was obtained. Some kinetic features were explained on the basis of analysis of the reaction mechanism. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 475–481, 2012     

Four Triterpene Oligoglycosides from the seeds of Aesculus Chinensis

TheseedsofAesculuschinensisBge.(Hippocastanaceae)havebeenusedasfolkmedicineforthetreatmentofdistensionandpaininchestandabdomenl.Untilnow,thereisnoreportonitschemicalconstituents.Thispaperdescribesstructureelucidationoftwonewcompounds,escinsIVa3andIVb4onthebasisofspectroscopicmethodsandcomparisonwithescinsla1andfo22.Amongthem,EscinlaIwasstudiedbyX-raydistractionanalysis.Compound3,whitepowder,showediRbandsduetocarboxylanda,p-unsaturatedesterat1740,1713and1640cm-'andstrongabsorptionbandsat34…     

Determination of Trace Lithium in Uranium Compounds by Adsorption on Activated Alumina Using a Micro-column Method

A novel method using a micro-column packed with active alumina as solid phase was proposed for separation of trace lithium from uranium compounds prior to determination. The method is based on a preliminary chromatographic separation of the total amount of uranium. This separation involves passing the solution containing sodium carbonate through active alumina and then eluting the trace lithium retained by the solid phase with a solution of sulfuric acid. Two modes, off-line and on-line micro-column preconcentration, were performed. In conjunction with atomic absorption spectrometry, this on-line preconcentration technique allows a determination of lithium at 10(-9) level. Both off-line and on-line mode operation conditions were investigated in separation and determination of trace lithium by micro-column method (length of column bed, flow rate, etc.). The adsorption capacity of activated alumina was found to be 343 microg g(-1) for lithium. Under the optimal operation condition, the detection limit (DL) of on-line preconcentration corresponding to three times the standard deviation of the blank (S/N = 3) was found to be 1.3 ng mL(-1) and the RSD of this method is 3.32% (n = 5). The on-line calibration graph was linear over the range 20 - 200 ng mL(-1). A good preconcentration factor 820 was achieved by experiment under the on-line mode. The developed method was applied to the analysis of trace lithium in nuclear grade uranium compounds.     

A Novel Synthesis of Alkylamino Substituted Methylenediphosphonates Using Bis(trichloromethyl) Carbonate and RCONR1R2

An efficient, economical and easy method for the synthesis of dimethylaminomethylenediphosphonates using bis(trichloromethyl) carbonate and RCONR1R2 has been developed, which proceeded under relatively mild conditions.     

Preparation and third-order nonlinear optical properties of self-organized complex oxide Ce:BaTiO3 quantum dots

Pulsed laser ablation epitaxial Strancky-Krastanow growth of self-organized complex oxide Ce:BaTiO3 quantum dots on MgO(100) substrates is demonstrated.Atomic force microscopy and X-ray diffraction are used to observe the structure and the growth process of the self-organized complex oxide quantum dots.The average dimension,height,and the density of self-organized complex oxide Ce:BaTiO3 quantum dots are given.The nonlinear refractive indexes of the wetting layer and the self-organized ordered quantum dots are determined by the single beam Z-scan method.The mechanisms of the nonlinear effect enhancement for these low-dimensional structure are discussed.     

BEPC-LINAC试验束上1GeV/c多粒子磁谱仪的设计和性能测量

试验束上2Q2D结构的磁谱仪系统由2块二极磁铁和2块四极磁铁以及位置灵敏探测器组成.该磁谱仪的接收立体角5×10^–4sr,动量范围0.2—1.3GeV/c.测量了聚焦面上的束流截面和动量谱.介绍了一种测量电子与质子飞行时间差的动量测量方法.     

Synthesis and Characterization of Heterobimetallic Aluminum‐Germanium(IV) Disulfides

Three heterobimetallic aluminum‐germanium(IV) disulfides are synthesized. The reaction of {LAl[(SLi)₂(THF)₂]}₂ ( 1 ) (L = HC(CMeNAr)₂, Ar = 2,6‐iPr₂C₆H₃) with Ph₂GeCl₂, Me₂GeCl₂, and GeCl₄, respectively, in THF afforded LAl(μ‐S)₂GePh₂ ( 2 ), LAl(μ‐S)₂GeMe₂ ( 3 ) and LAl(μ‐S)₂Ge(μ‐S)₂AlL ( 4 ) in good yields. Compounds 2 , 3 and 4 were investigated by elemental analysis, NMR, EI‐MS and 3 was also characterized by single crystal X‐ray structural analysis.     

Cleavage of polystyrene‐b‐poly(ethylene oxide) block copolymers with a trithiocarbonate linkage in solutions

In this work, the polystyrene‐b‐poly(ethylene oxide) (PS‐b‐PEO) block copolymers with a trithiocarbonate group between the blocks were prepared by polymerization of styrene in the presence of a trithiocarbonate reversible addition fragmentation chain transfer (RAFT) agent connected with PEO. Decomposition of the trithiocarbonate group by UV irradiation was investigated in three different types of solvent: tetrahydrofuran (THF, common solvent for both blocks), cyclohexane/dioxane mixture (selective solvent for the PS block) and N,N‐dimethylformamide (DMF)/ethanol mixture (selective solvent for the PEO block). It is found that cleavage of the block copolymers can take place in all these three solvents and the cleavage ratio ranges from 76 to 86%. The micellar morphologies in selective solvents before and after cleavage were examined. It is observed that the size of the micelles is reduced after cleavage and sometimes aggregation of the micelles occurs due to removal of the corona of micelles. It shows that this work provides a facile and general method for synthesis of cleavable block copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3834–3840, 2010