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Microwave peak absorption frequency of liquid

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Science china(Physics,Mechanics & Astronomy) 2008年第9期51卷 1254-1263页

作者： HAN GuangZe1 & CHEN MingDong2 1 department of Physics,south china university of technology,guangzhou 510640,china 2 guangzhou Auto College,south china university of technology,guangzhou 510800,china 1. department of Physics South China University of Technology Guangzhou 510640 China 2. guangzhou Auto College South China University of Technology Guangzhou 510800 China

Microwave-assisted extraction is a new effective method which has practical ap-plications in many fields. Microwave heating is one of its physical mechanisms,and it also has the characteristic of selectivity. When the applied microwave fre-quency equals a certain absorption frequency of the material (or specific compo-nent),the material will intensively absorb microwave energy. This is also known as resonant absorption,and the frequency is called the peak absorption frequency which depends on the physical structure of the material. In this work,dynamic hy-drogen bond energy was included in molecular activation energy; with the liquid cell model,the expression of interaction energy between dipolar molecules was derived. The rotational relaxation time was gotten from the Eyring viscosity formula. Then based on the relationship between dielectric dissipation coefficient and re-laxation time,the expression of microwave peak absorption frequency as a func-tion of the material physical structure,rotational inertia and electrical dipole mo-ment of molecules was established. These theoretical formulas were applied to water and benzene,and the calculated results agree fairly well with the experi-mental data. This work can not only deepen the study of the interaction between microwave and material,but also provide a possible guide for the experiment of microwave-assisted extraction.

关键词： microwave-assisted extraction microwave heating relaxation time liquid viscosity peak absorption fre-quency

EXISTENCE OF INFINITELY MANY SOLUTIONS FOR ELLIPTIC PROBLEMS WITH CRITICAL EXPONENT

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Acta Mathematica Scientia 2004年第3期24卷 395-402页

作者：傅红卓沈尧天 department of mathematics South China University of Technology Guangzhou 510640 China Department of Mathematics University of Science and Technology of China Hefei 230026 China department of mathematics South China University of Technology Guangzhou 510640 Chinahis paper is concerned with the following nonlinear Dirichlet problem:where △pu = div(| ▽u|p- 2 ▽u) is the p-Laplacian of u Ωis a bounded domain in Rn (n > 3) 1 < p < n p = -pn/n-p is the critical exponent for the Sobolev imbedding λ> 0 and f(x u) satisfies some conditions. It reaches the conclusion that this problem has infinitely many solutions. Some results as p = 2 or f(xu) = |u|q-2u where 1 < q < p are generalized.

This paper is concerned with the following nonlinear Dirichlet problem:where △pu = div(| ▽u|p- 2 ▽u) is the p-Laplacian of u, Ω is a bounded domain in Rn (n > 3), 1 0 and f(x, u) satisfies some conditions. It reaches the conclusion that this problem has infinitely many solutions. Some results as p = 2 or f(x,u) = |u|q-2u, where 1 < q < p, are generalized.

关键词： critical Sobolev exponent concentration compactness principle genus infinitely many solutions

Transitional function of DG to CA3 in the hippocampus

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Progress in Natural Science:Materials International 2007年第12期17卷 1436-1444页

作者： Yan Chuankui1 and Liu Shenquan2(1. department of mathematics, Hangzhou Normal university, Hangzhou 310036, china 2. department of Applied mathematics, School of Mathematical Sciences, south china university of technology, guangzhou 510640, china) department of mathematics Hangzhou Normal University Hangzhou 310036 China department of Applied mathematics School of Mathematical Sciences South China University of Technology Guangzhou 510640 China

Using single cell channel model, the transmission features of CA3-DG network in the hippocampus are investigated. The influence of the stimulation on discharge pattern of pyramidal neurons is analyzed, which shows that it starts with period spiking discharges, followed by period-doubling bifurcation to chaos, and period 3 discharge evolving into chaos, and ultimately a period of bursting discharges. By the synaptic model, the CA3-DG network model is constructed, which analyzes the summation of postsynaptic currents in the network, the influence of postsynaptic current on discharge rhythm as well as the mechanism of bursting discharges. The strong capacity of spatiotemporal encoding in the network indicates the features of CA3 network during the information transmission process in the hippocampus. The modeling result with time delay of the synaptic transmission is in accordance with the experimental phenomena of action potential in the hippocampus.

关键词： hippocampus CA3-DG period-doubling bifurcation chaos.

Electrical stimulation for brighter persistent luminescence

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Light(Science & Applications) 2024年第8期13卷 1590-1601页

作者： xilin Ma Yuhua Wang Takatoshi Seto Key Laboratory for Special Function Materials and Structural Design of the Ministry of Education National&Local Joint Engineering Laboratory for Optical Conversion Materials and Technology of National Development and Reform CommissionDepartment of Materials ScienceSchool of Materials and EnergyLanzhou UniversityNo.222South Tianshui RoadLanzhouGansu 730000China

An immature understanding of the mechanisms of persistent luminescence(PersL)has hindered the development of new persistent luminescent materials(PersLMs)with increased *** this regard,in-situ direct current(DC)electric field measurements were conducted on a layered structure composed of the SrAl_(2)O_(4):Eu^(2+),Dy^(3+)phosphor,and an *** this study,the photoluminescence(PL)and afterglow properties were investigated with respect to voltage by analyzing the current signal and thermoluminescence(TL)*** intensity of PersL increased due to a novel phenomenon known as“external electric field stimulated enhancement of initial brightness of afterglow”.This dynamic process was illustrated via the use of a rate equation approach,where the electrons trapped by the ultra-shallow trap at 0.022 eV could be transferred through the conduction band during long *** afterglow intensity could reach 0.538 cdm^(-2)at a 6 V electric *** design of an electric field stimulation technique enables the enhancement of the intensity of PersLMs and provides a new perspective for exploring the fundamental mechanics of certain established PersLMs.

关键词： spectroscopy luminescence conduction

Representation of Congruences on Regular Semigroups with Inverse Transversals

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Acta Mathematica Sinica,English Series 1999年第3期15卷 347-352页

作者： Limin Wang xilin tang department of mathematics, south china Normal university, guangzhou 510631, P. R. china department of mathematics, guangzhou Teacher’s College, guangzhou 510400, P. R. china department of mathematics South China Normal University Guangzhou P. R. China department of mathematics Guangzhou Teacher’s College Guangzhou P.R. China

For a regular semigroup with an inverse transversal, we have Saito’s structure W(I, S°, Λ, *, α,β). We represent congruences on this kind of semigroups by the so-called congruence assemblage which consist of congruences on the structure component parts I, S° and Λ. The structure of images of this type of semigroups is also presented.

关键词： Inverse transversal Congruence Congruence assemblage

On the Existence of Nontrivial Solutions of Quasi-asymptotically Linear Problem for the P-Laplacian

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Acta Mathematicae Applicatae Sinica 2002年第4期18卷 599-606页

作者： Zhi-hui Chen, Yao-tian Shendepartment of Applied mathematics, south china university of technology, guangzhou 510640, china department of Applied mathematics South China University of Technology Guangzhou 510640 China

In this paper, we study the existence of nontrivial solutions for the following Dirichlet problem for the p-Laplacian (p > 1):where Ω is a bounded domain in Rn (A≥1) and f(x,u) is quasi-asymptotically linear with respect to |u|p-2 u at infinity. Recently it was proved that the above problem has a positive solution under the condition that f(x, s)/sp-1 is nondecrcasing with respect to s for all x ∈Ω and some others. In this paper. by improving the methods in the literature, we prove that the functional corresponding to the above problem still satisfies a weakened version of (P.S.) condition even if f(x, s)/sp-1 isn't a nondecreasing function with respect to s, and then the above problem has a nontrivial weak solution by Mountain Pass Theorem.

关键词： Quasi-asymptotically linear weak solution critical point Palais-Smale type condition

A Novel Sulfided Mo/C Catalyst for Direct Vapor Phase Carbonylation of Methanol at Atmospheric Pressure

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Journal of Natural Gas Chemistry 2003年第1期12卷 31-36页

作者： Feng Pengdepartment of Chemical Engineering, south china university of technology, guangzhou 510640, china department of Chemical Engineering South China University of Technology Guangzhou 510640 China

The direct carbonylation of methanol, without any halide in the feed as apromoter, is presented. A series of Mo catalysts supported on activated carbon, γ-Al_2O_3 and SiO_2were prepared. The results show that the support greatly affects the Mo catalyst in the directvapor-phase carbonylation of methanol, and activated carbon is the best supports of the investigatedsupports. In addition, the relationships between adsorptions of NH_3 and CO and carbonylation ofmethanol were investigated. A novel sulfided Mo/C catalyst had high activity and selectivity for thevapor phase carbonylation of methanol to methyl acetate without the addition of a CH_3I promoter tothe feed. The reaction conditions were optimized at a reaction temperature of 573 K, a methanolconcentration of 23 mol% and a carbon monoxide space velocity of 3,000 L/(kg·h). Under theseoptimal conditions a methanol conversion of 50%, carbonylation selectivity of 80 rnol%, andspace-time yield of 8.0 mol/(kg·h) were obtained. The active phase of this novel sulfided Mo/Ccatalyst is the non-crystalline phase, and the active component is present as MoS_(2.5) on thesurface of the activated carbon.

关键词： methanol carbonylation sulfided catalyst molybdenum catalystsupport activated carbon heterogeneous catalysis

Invariant basis number of the ring of Morita context

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Chinese Science Bulletin 1997年第8期42卷 633-636页

作者： HAO Zhifengdepartment of Applied mathematics, south china university of technology, guangzhou 510641, china department of Applied mathematics South China University of Technology Guangzhou 510641 China

A ring is said to be an IBN ring if for every free left module A,every two bases of A havethe same *** class of such a ring has been applied to alegbraic K-theory and *** free module over the IBN ring can be defined b... 详细信息

关键词： ring of Morita context IBN ring Five Lemma.

ON THE INVERSE IMAGE SET OF RATIONAL FUNCTIONS

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Acta Mathematica Scientia 2007年第3期27卷 541-548页

作者：孙道椿 department of mathematics South China Normal University

This article studies the inverse image of rational functions. Several theorems are obtained on the Julia set expressed by the inverse image, and a mistake is pointed out in ***＇ theorem incidentally.

关键词： Rational dynamical system Julila set Fatou component