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Acid-base behavior of cryptand 1, 4, 7, 10, 13, 16, 21, 24-octaaza-bicyclo [8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hexone and complex formation

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Rare Metals 2002年第1期21卷 12-19页

作者： MO Zunli, CHEN Hong and GAO Jinzhang Institute of Chemistry, northwest normal university, Lanzhou 730070, China Institute of Chemistry Northwest Normal University Lanzhou 730070

The bicyclic cryptand 1,4,7, 10,13,16,21, 24-octaaza-bigcyclo [8, 8,8] hexacosan-3, 8, 12, 17, 20, 25-hex-one (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of discrete neutral macrobicyclic units; the two cycles share the two tertiary amine nitrogen atoms, which exhibit an endo-cndo conformation. Three identical branches formed by 1, 2-diaminoethane link the two tertiary amine groups. The protonation reactions of cryptand (COBH) and its complex formation with copper (II) were investigated by potentiometry in water and in a DMSO/water (80:20 in mass ratio) mixture as solvents. The cryptand acts as a his-base through its two N-bridgehead and exhibits a strong cooperativity that favors the first protonation and makes the second one difficult (△pK= 5.0). An inward rotation of the amide groups to form hydrogen bonds accounts for this cooperativity. The interaction of COBH with copper (II) leads to several binuclear complex proton contents.

关键词： COBH(cryptand 1,4,7, 10, 13, 16, 21, 24-octaaza-bigcyclo hexacosan -3, 8, 12, 17,20,25 - hex-one) macrobicyclic acid-base behavior complex formation proton contents

Polarographic behavior of 1,4,7-triazacycloanane-N,N',N"-tris (meth-ylphonic acid) (NOTP)-Bi(Ⅲ) complex

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Rare Metals 2002年第4期21卷 250-254页

作者： GAO Jinzhang, HE Hui, YANG Wu, and RANG JingwanInstitute of Chemistry, northwest normal university, Lanzhou 730070, China Institute of Chemistry Northwest Normal University Lanzhou 730070

The polargraphic behavior of Bi(Ⅲ)-NOTP complex has been investigated inaqueous solution. It was found that under the conditions of pH 3.0 and of 0.02 mol/L NH_4Cl, theBi(Ⅲ)-NOTP system gives a sensitive second order derivative wave at -0.340 V(vs SCE), which isproved to be an adsorptive complex wave. The composition of the complex is Bi(Ⅲ):NOTP. Furthermore,the peak current is linear to the concentration of Bi(Ⅲ) in the range from 3.0x10^(-8) to5.0x10^(-6) mol/L. Artificial and practical samples have been detected with high sensitivity andreceptivity.

关键词： determination of bismuth Bi(Ⅲ)- NOTP complex 1,4,7-triazacycloanane-N,N′, N″-tris(methylphonic acid)

Short cycle structures for graphs on surfaces and an open problem of Mohar and Thomassen

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Science China Mathematics 2006年第2期49卷 212-224页

作者： REN Han & DENG Mo Department of Mathematics, East China normal university, Shanghai 200062, China College of Mathematics & Information Science, northwest normal university, Lanzhou 730070, China 1. Department of Mathematics East China Normal University Shanghai 200062 China 2. College of Mathematics & Information Science Northwest Normal University Lanzhou 730070 China

In this paper we investigate cycle base structures of a (weighted) graph and show that much information of short cycles is contained in an MCB (i.e., minimum cycle base). After setting up a Hall type theorem for base-transformation, we give a sufficient and necessary condition for a cycle base to be an MCB. Furthermore, we show that the structure of MCB in a (weighted)graph is unique. The property is also true for those having a longest length (although much work has been down in evaluating MCB, little is known for those having a longest length). We use those methods to find out some unknown properties for short cycles sharing particular properties in (unweighted) graphs. As applications, we determine the structures of short cycles in an embedded graph and show that there exist polynomially bounded algorithms in finding a shortest contractible cycle and a shortest two-sided cycle provided such cycles exist. Those answer an open problem of B. Mohar and C. Thomassen.

关键词： cycle base facial cycle graph embedding.

Preparation and characterization of Ni/Co bimetallic nano-clusters

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Journal of university of Science and Technology Beijing 2003年第4期10卷 46-49页

作者： Jinzhang Gao, Fei Guan, Yongjun Ma, and Jingwan KangInstitute of Chemistry, northwest normal university, Lanzhou 730070, China. Inst. of Chem. Northwest Normal Univ. Lanzhou 730070 China

Ni/Co bimetallic nano-cluters have been prepared from the aqueous solution byreducing their corresponding metal salts under suitable conditions. The experimental conditionsincluding the type and concentration of protective agent, feeding order and the pH of the solutionthat influence the average particle size have been studied in detail. Transmission electronmicroscopy (TEM) indicates that the shape of those bimetallic nano-cluster particles is *** alloy structure has been shown by X-ray powder diffraction (XRD). The X-ray photoelectronspectroscopic (XPS) data have confirmed that the nickel and cobalt in the bimetallic nano-clustersare in the zero-valence state.

关键词： Ni/Co alloy chemical synthesis nano-cluster characterization

Determination of Trace Amount of Yttrium with Bromopyrogallol Red by solid-phase Spectrophotometry

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Rare Metals 2001年第3期20卷 202-204页

作者： Jinzhang Gao,Gang Ni, Li Yuan, Jingwan Kang Department of Chemistry, northwest normal university, Lanzhou 730070, China NW normal Univ Dept Chem Lanzhou 730070 Peoples R China

A simple and sensitive method for the determination of trace amount of yttrium by solid-phase spectrophotometry has been studied. Yttrium can form a 1 : 1 complex with bromopyrogallol red (BPR) on resin, which was determined directly at 605 nm, pH=6.5. It has a highly sensitivity (epsilon = 6.3 x 10(6)) which is 300-fold higher than the corresponding spectrophotometry in solution. The method was applied to the determination of yttrium in churchite.

关键词： solid-phase spectrophotometry bromopyrogallol red (BPR) yttrium

(2+1)-Dimensional Electron Acoustic Solitary Waves in an Unmagnetized Collisionless Plasma with Vortex-Like Hot Electrons

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Communications in Theoretical Physics 2007年第2期47卷 339-342页

作者： LIN Mai-Mai DUAN Wen-Shan Department of Physics,northwest,normal university,Lanzhou 730070,China Department of Physics Northwest Normal University

In this paper,(2+1)-dimensional electron acoustic waves (EAW) in an unmagnetized collisionless plasmahave been studied by the linearized method and the reductive perturbation technique,*** dispersionrelation and a modified Kadomtsev Petviashvili (KP) equation have been obtained for the EAW in the plasma consideringa cold electron fluid and a vortex-like hot *** is found from some numerical results that the parameter β (theratio of the free hot electron temperature to the hot trapped electron temperature) effects on the amplitude and thewidth of the electron acoustic solitary waves (EASW).It can be indicated that the free hot electron temperature andthe hot trapped electron temperature have very important effect on the characters of the propagation for the EASW.

关键词： electron acoustic solitary wave vortex-like hot electrons reductive perturbation method

Solid-liquid solvent extraction of metal ions

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Journal of university of Science and Technology Beijing 2003年第3期10卷 1-7页

作者： Bo Peng, Haiyan Fan, and Jinzhang GaoDepartment of Chemistry, northwest normal university, Lanzhou 730070, China Department of Chemistry Northwest Normal University Lanzhou 730070 China

An overview of extraction of some trace metal ions using molten solvent (lowmelting substance) during last two decades is presented. The development of this technique since itsinception is briefly traced. The comparison of extraction efficiency, thermodynamics and kineticsmainly involving extraction of rare earth ions between molten solvent extraction at high temperatureand usual liquid-liquid extraction at room temperature are discussed in detail. The variousparameters obtained from the previous and present studies such as equilibrium extraction constantK_(ex), pH_(1/2), thermodynamic and kinetic data are displayed in tabular form. Finally, the currentdemands, disadvantages and future prospects are also evaluated.

关键词： solid-liquid solvent extraction metal ions thermodynamics kinetics determination

Molten solvent extraction behavior of trivalent La, Sm, Dy, and Yb with tri-n-butyl phosphate into molten paraffin wax at 60 ℃

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Rare Metals 2002年第1期21卷 7-11页

作者： PENG Bo, GAO Jinzhang, FAN Haiyan, KANG Jingwan, and YANG Wu Department of Chemistry, northwest normal university, Lanzhou 730070, China Department of Chemistry Northwest Normal University Lanzhou 730070

The extraction behavior of La^3+, Sm^3+, Dy^3+, and Yb^3+ insodium acetate-acetic acid medium was studied with tri-N-butylphosphate (TBP) at 60 deg. C using paraffin wax as a diluent. Theextraction percentage is greater than 85/100 in the pH range of 6 to8. The result of slope analysis method indicates that thecompositions of the extracted species are different between the lightand heavy rare ear this. The formula of the extracted species isfound to be La (TBP) (OH) (Ac)_2 for La^3+ and Yb (TBP) (OH)_3 forYb^3+. The effects of extracting time, the concentration of TBP inthe organic phase and salts on the extraction efficiency were alsodiscussed.

关键词： solvent extraction rare earth TBP Paraffin wax

Nonlinear Behavior and Domain Feature at Oil/Water Interface

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Chinese Chemical Letters 2003年第10期14卷 1062-1065页

作者： Jin Zhang GAO, Kan Jun SUN, Wu YANGChemistry and Chemical Engineering College, northwest normal university, Lanzhou 730070 Chemistry and Chemical Engineering College Northwest Normal University Lanzhou 730070

Studies on nonlinear behavior at oil/water interface membrane were performed. This system showed rhythmic oscillations and chaos of electrical potential in a given concentration domain. The nonlinear behavior response at the liquid membrane apparently resembled that of biological chemoreceptive membrane. The possibility of developing a new type of chemical sensor with the ability to simulate substance equilibrium in living organisms was suggested in the paper.

关键词： Nonlinear behavior oscillations oil/water interface domain.