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Showing papers by "Henan Normal University published in 1998"


Journal ArticleDOI
TL;DR: In this article, the infinite-dilution apparent molar volumes of 6 mol-kg−1 aqueous guanidine hydrochloride were determined at 5, 15, 25, and 35°C from precise density measurements.
Abstract: The infinite-dilution apparent molar volumesV 2φ o for glycine, DL-alanine, DL-α-amino-n-butyric acid, DL-valine, DL-leucine, and L-serine in 6 mol-kg−1 aqueous guanidine hydrochloride were determined at 5, 15, 25, and 35°C from precise density measurements. Using these data, the standard volumes of transfer, Δt V°, from water to 6m> aqueous guanidine hydrochloride solution were calculated. A linear relationship was found between V 2φ o and temperature. Both V 2φ o and Δt V° vary linearly with increasing number of carbon atoms in the alkyl chain of the amino acids. The results show that the apparent molar volumes at infinite dilution for (NH 3 + ,COO-) groups increase with increasing temperature and those for CH2 and the other alkyl chains are almost constant. These results also shows that guanidine hydrochloride has stronger interactions with amino acids than urea. These phenomena are discussed in terms of the cosphere overlap model.

173 citations


Journal ArticleDOI
TL;DR: In this article, the Eu3+-doped Y3Al5O12 phosphor ultrafine powders were synthesized by the sol-gel method using metal alkoxide at the lower temperature of 1000°C.

72 citations


Journal ArticleDOI
Quanmin Li1, Qi Liu1, Qing-Fen Zhang1, Xian-Jun Wei1, Jin-Zhi Guo1 
01 Aug 1998-Talanta
TL;DR: A study of the transport of Cd(2+) ions through a triisooctylamine-sorbitan monooleate (Span 80)-dimethylbenzene liquid membrane has been performed with varying concentrations of HCl, KI, TIOA, Span 80 and NaOH in the feed, membrane and stripping solutions.

29 citations


Journal ArticleDOI
TL;DR: In this paper, the additivity rule is employed to obtain the total (elastic+inelastic) cross-sections for positron scattering from molecules including a number of diatomic, polyatomic molecules (H2, N2, HCl, CO2, NH3, SF6, CH4, C2H4 and C3H8) over an incident energy range of 10-1000 eV.
Abstract: The additivity rule is employed to obtain the total (elastic+inelastic) cross-sections for positron scattering from molecules including a number of diatomic, polyatomic molecules (H2, N2, HCl, CO2, NH3, SF6, CH4, C2H4 and C3H8) over an incident energy range of 10-1000 eV. The total cross-sections (TCS) of the constituent atoms of molecules are obtained by employing a complex optical model potential (composed of static, polarization and absorption potential). The present results are compared with experimental data and other theoretical calculations, good agreement is obtained in intermediate- and high-energy region.

28 citations


Journal ArticleDOI
TL;DR: Criteria for the boundedness of solutions and persistence is obtained for the cases where the nutrient is supplied at a constant rate and the nutrient supply is time-dependent.
Abstract: In this paper, we consider competition between plasmid-bearing and plasmid-free organisms with nutrient recycling and an inhibitor in a chemostat-type systems. We discuss the cases where the nutrient is supplied at a constant rate and the nutrient supply is time-dependent. For each case, we obtain criteria for the boundedness of solutions and persistence.

25 citations


Journal ArticleDOI
Zhaorong Chang1, Gongan Li1, Yujuan Zhao1, Yunchang Ding1, Jianguo Chen1 
TL;DR: In this paper, the influence of various conditions in spherical nickel hydroxide preparation on its electrochemical properties is studied, and the optimum conditions and reference data for preparing spherical nickel hydride with excellent properties are provided.

23 citations


Journal ArticleDOI
TL;DR: In this paper, the existence and uniqueness results for positive radial solutions of a class of quasilinear elliptic equations in aN-ball or an annulus without monotone assumptions on the nonlinear termf were obtained.
Abstract: Existence and uniqueness results are obtained for positive radial solutions of a class of quasilinear elliptic equations in aN-ball or an annulus without monotone assumptions on the nonlinear termf It is also proved that there is no non-radial positive solution

22 citations


Journal ArticleDOI
TL;DR: Methylammonium chlorochromate adsorbed on alumina is an easily prepared and stable reagent and with this reagent oximes and p-nitropheny-lhydrazones are converted to their corresponding carbonyl compounds in good yields as discussed by the authors.

20 citations


Journal ArticleDOI
TL;DR: In this article, the dissociation constants of methyl orange (H + In − ) have been determined at 25°C and an ionic strength of 0.1 ǫ l − 1 in water and in mixed aqueous solutions of methanol (10−90 ǔ), ethanol (10-70 ǒ), iso-propanol ( 10−60 ǵ), and tert-butanol (10 −50 Ǫ ) by spectrophotometric measurements.

18 citations


Journal ArticleDOI
TL;DR: In this paper, the authors performed exact numerical calculation of electron-He scattering with one-, two-, and three-photon exchange and compared their results with the Kroll-Watson approximation (KWA) results and the recent experiments.
Abstract: Electron-atom scattering at small scattering angles $(0\ifmmode^\circ\else\textdegree\fi{}--25\ifmmode^\circ\else\textdegree\fi{})$ in the presence of an intense radiation field is investigated employing second Born approximation. We perform exact numerical calculation of differential cross sections of electron-He scattering with one-, two-, and three-photon exchange and compare our results with the Kroll-Watson approximation (KWA) results and the recent experiments; our results are much better than KWA's for small angle scattering compared with experiments.

17 citations


Journal ArticleDOI
TL;DR: In this paper, the M/G ratio, dyad and triad frequencies in the sodium alginate chain were determined from 13C-nmr spectra, and the interaction of the alginates with the univalent cations K+ ion and Na+ ion was investigated by viscometry and membrane osmometry.
Abstract: The M/G ratio, dyad and triad frequencies in the sodium alginate chain, were determined from 13C-nmr spectra. The interactions of sodium alginate in solution with the univalent cations K+ ion and Na+ ion have been investigated by viscometry and membrane osmometry. The dependencies of intrinsic viscosity, Huggins constant, and second virial coefficient on ionic strength were observed, and the maximums in reduced viscosity were obtained in low KCl and NaCl concentrations, respectively. These show that the electroviscous effects play an important role in polyelectrolyte solution, and the effect of the Na+ ion on aqueous solution of sodium alginate is greater than the K+ ion. The experimental observations are interpreted in terms of ion-pair formation with carboxyl groups of mannuronate and isolated guluronate residues and cooperation “egg-box” binding between polyguluronate chain sequence. The difference of interaction between univalent cations and alginate chains in solution is attributed to the ability of their binding with the polyion, which depends on the properties of ions itself. © 1998 John Wiley & Sons, Inc. Biopoly 46: 395–402, 1998

Journal ArticleDOI
TL;DR: In this paper, the authors presented a method that is sometimes successful in constructing a system of orthogonal idempotents that are constant on {[ θ 1 ], [ θ 2 ], …, [ ǫ k ]}.

Journal ArticleDOI
TL;DR: In this article, p-nitrophenylhydrazones are converted to corresponding carbonyl compounds using dimethylammonium chlorochromate adsorbed on alumina under non-aqueous condition.

Journal ArticleDOI
TL;DR: In this article, the possibility of probing anomalous top quark charged current couplings in single quark production at a high-energy $e\ensuremath{\gamma}$ collider was studied in the effective Lagrangian approach.
Abstract: We study in the effective Lagrangian approach the possibility of probing anomalous top quark charged current couplings in single top quark production at a high-energy $e\ensuremath{\gamma}$ collider. We analyze all possible dimension-six $\mathrm{CP}$-conserving operators which can give rise to an anomalous $\mathrm{Wtb}$ coupling which represents new physics effects generated at a higher-energy scale. For those operators which also give rise to anomalous $\mathrm{Zb}\overline{b}$ or right-handed $\mathrm{Wtb}$ couplings, we find that they are strongly constrained by the existing ${R}_{b}$ and $\stackrel{\ensuremath{\rightarrow}}{b}s\ensuremath{\gamma}$ data. As a result, a collider with a luminosity of the order of $100{\mathrm{fb}}^{\mathrm{\ensuremath{-}}1}$ is required to observe anomalous effects. For other operators which currently are subject to no strong constraints, the high-energy $e\ensuremath{\gamma}$ collider can probe their couplings effectively because of the clean environment of such a collider.

Journal ArticleDOI
TL;DR: In this article, the effects of salt ions on the cupric association in cupric-induced alginate solutions were investigated by means of viscosity measurements and the mechanisms of complex formation in the presence of the simple added salt were studied.

Journal ArticleDOI
TL;DR: In this article, a treatment of various alcohols with aliphatic carboxylic acids in the presence of a catalytic amount of Fe2(SO4)3 · xH2O to give the corresponding esters in good yields is described.


Journal ArticleDOI
TL;DR: In this paper, a simple and highly sensitive fluorimetric method is reported for the determination of ultratrace amount of ascorbic acid in pharmaceuticals, fruit juices and vegetables.
Abstract: A simple, fast and highly sensitive fluorimetric method is reported for the determination of ultratrace amount of ascorbic acid. The method is based on the activating effect of ascorbic acid on the oxidation of rhodamine 6G by potassium bromate in the presence of vanadium(V), which acts as a catalyst. The detection limit for ascorbic acid is 0.62ng/ml; the linear range of the determination is 1.6-28ng/ml The proposed method was used to determine ascorbic acid in pharmaceuticals, fruit juices and vegetables with satisfactory results.

Journal ArticleDOI
W. Bian1
TL;DR: The relation between the reachable sets of the semilinear evolution equation systems on a Banach space is studied in this paper, where it is shown that f is not independent of the control u, and no compactness assumptions on A or f are imposed in some of the main results.
Abstract: The relations between the (strong) reachable sets of the semilinear evolution equation systems x′(t) + A(t)x(t) = f(t, x(t), u(t)) + Hu(t), x′(t) + A(t)x(t) = f(t, x(t), Hu(t)) + Hu(t) on a Banach space, and their corresponding linear systems are studied. Compared with previous results, the systems considered here are more general (f is not independent of the control u), no compactness assumptions on A or f are imposed in some of our main results, and we suppose f is a set-contraction rather than Lipschitz and have less restriction on the contraction coefficient. Other kinds of conditions are involved to guarantee the approximate controllability.

Journal ArticleDOI
TL;DR: In this article, pseudo Goldstone boson corrections to gg! tt production rates in technicolor models with and without top-color at the As50.5 and 1.5 TeV photon colliders were studied.
Abstract: We study pseudo Goldstone boson corrections to gg! ttproduction rates in technicolor models with and without top-color at the As50.5 and 1.5 TeV photon colliders. We find that, for reasonable ranges of the parameters, the corrections are large enough to be observable, and the corrections in models with top-color are considerably larger than those in models without top-color, and they are all significantly larger than the corresponding corrections in the minimal supersymmetric standard model ~MSSM! with tanb>1. Therefore, the two kinds of technicolor models and the MSSM with tanb>1 can be experimentally distinguished. @S0556-2821~98!02605-8#



Journal ArticleDOI
TL;DR: In this article, the inclusion complex of benzaldehyde (BA) with β-cyclodextrin (β-CD) was prepared and was studied by thermal analysis and X-ray diffractometry.
Abstract: The inclusion complex of benzaldehyde (BA) with β-cyclodextrin (β-CD) was prepared and was studied by thermal analysis and X-ray diffractometry. The composition of the complex was identified by TG and elemental analysis as β-CD·BA·9H2O. TG and DSC studies showed that the thermal dissociation of β-CD·BA·9H2O took place in three stages: dehydration in the range 70-120°C; dissociation of β-CD·BA in the range 235-270°C; and decomposition of β-CD above 280°C. The kinetics of dissociation of β-CD·BA in flowing dry nitrogen was studied by means of TG both at constant temperature and at linearly increasing temperature. The results showed that the dissociation of β-CD·BA was dominated by a one-dimensional random nucleation and subsequent growth process (A2). The activation energy E was 124. 8 kJ mol-1, and the pre-exponential factor A 5.04·1011 min-1.


Journal ArticleDOI
01 Aug 1998-Talanta
TL;DR: It is concluded that the higher stabilization of both 2,2'-bipyridyl and its protonated form by dispersion forces and of the proton by its interaction with solvent molecules in the mixed solvents compared with that in water are largely responsible for the observed changes of pK(a) with composition.

Journal ArticleDOI
TL;DR: In this paper, the stability of β-cyclodextrin·ethyl benzoate·6H2O(β-CD·C6H5COOC2H5·6 H2O) was investigated by TG and DSC.
Abstract: The stability of β-cyclodextrin·ethyl benzoate·6H2O(β-CD·C6H5COOC2H5·6H2O) was investigated by TG and DSC. The mass loss takes place in three stages: the dehydration occurs at 50-120°C; the dissociation of β-CD·C6H5COOC2H5occurs at 200-260°C; the decomposition of β-CD begins at 280°C. The kinetics of the dissociation of β-CD·C6H5COOC2H5in a dry nitrogen flow was studied by means of thermogravimetry both at constant temperature and linearly increasing temperature. The results show that the dissociation of β-CD·C6H5COOC2H5is dominated by a three-dimensional diffusion process (D3). The activation energy E is 116.19 kJ mol-1and the pre-exponential factor A 6.5358·109min-1. Cyclodextrin is able to form inclusion complexes with a great variety of guest molecules, and the studies focus on the energy of binding between cyclodextrin and the guest molecule. In this paper, the β-cyclodextrin·ethyl benzoate inclusion complex was studied by fluorescence spectrophotometry and infrared absorption spectroscopy, and the results show that the stable energy of inclusion complexes of β-CD with weakly polar guest molecules consists mainly of van der Waals interaction.

Journal ArticleDOI
TL;DR: In this article, the mass of glueballs is calculated in the B.S. equation framework under instantaneous approximation, and the wave function of B-S. equations is obtained.

Journal ArticleDOI
TL;DR: In this article, a simple method for the preparation of bis (substituted phenyl) carbodiazone compounds (ArN=NCON=NAr) was reported.

Journal ArticleDOI
Guo-xing Ju1, Guo-xing Ju2, Shi-kun Wang2, Ke Wu2, Chi Xiong2 
TL;DR: In this article, the symmetries of the reflection equation for open one-dimensional spin-chain models were analyzed and the Lax pair for open boundary conditions was given. But the symmetry analysis was not extended to other spin-chains.
Abstract: We analyze the symmetries of the reflection equation for open XYZ model and find their solutions K+/- case by case. In the general open boundary conditions, the Lax pair for open one-dimensional XYZ spin-chain is given.

Journal ArticleDOI
TL;DR: In this article, the nonlinear stability of stationary discrete shocks for the Lax-Friedrichs scheme approximating nonconvex scalar conservation laws is proved without smallness restrictions on the initial perturbations provided that the summation of the original perturbation is zero.
Abstract: The nonlinear stability of stationary discrete shocks for the Lax-Friedrichs scheme approximating non-convex scalar conservation laws is proved without smallness restrictions on the initial perturbations provided that the summation of initial perturbation is zero. The long time behavior of the Lax-Friedrichs is also investigated for a rather broad class of initial data. The selection of the discrete weight function plays a crucial role. The detailed study of discrete error equations is a major technical involvement.