直径为d的n阶树的谱半径

二分图的特征值在量子化学中有意义，因此研究其图论性质和其特征值间的关系是有背景的，设Pd＋1（[d＋2/2],n-d-1,Pd＋1（[d＋4/2],n-d-1）分别为路Pd＋1的第[d＋2/2]和第[d＋4/2]个顶点上接出n-d-1条悬挂边所得到的树，本文证明了：若把所有直径为d（d≥1）的n阶树按其最大特征值从大到小的顺序排列，则排在前两位的依次是Pd＋1（[d＋2/2],n-d-1,Pd＋1（[d＋4/2],n-d-1） 。     

ADSORPTION OF 2,4-DICHLOROPHENOL IN AQUEOUS SOLUTION ONTO ADSORPTION RESIN MODIFIED BY N-ACETYLANILINE

A hypercrosslinked adsorption resin （ZH-05） modified by N-acetylaniline in the post crosslinking process was prepared. The adsorption properties of ZH-05 toward 2,4-dichlorophenol in comparison with granular activated carbon （GAC） and Amberlite XAD-4 were observed. The present study mainly focuses on the static equilibrium adsorption behaviors, desorption profiles and the proof of chemisorption. The results show that the Langmuir equation can give a perfect fitting to experimental data, and high temperature was favorable for adsorption of 2,4-dichlorophenol on ZH-05. A related equation was used to correlate the amount of chemisorption and the suppositionai chemisorption equilibrium concentration of adsorbate in aqueous solution. The adsorption capacities from different ranges of temperature and the static desorption experiment both reveal the same conclusion, i.e., the adsorption of 2,4-dichlorophenol from water on ZH-05 is a coexistent process of physical adsorption and chemical transition as on GAC.     

Alum (KAl(SO4)2 · 12H2O) Catalyzed One-Pot Synthesis of Coumarins under Solvent-Free Conditions

Alum (KAl(SO₄)₂ · 12H₂O) is used as an efficient catalyst in the Pechmann condensation of phenol derivatives with β-keto esters leading to the formation of coumarins in excellent yields under solvent-free conditions. This methodology offers significant improvements for the synthesis of coumarins with regard to the yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts and solvents.     

ADSORPTION OF TANNIN ACID ONTO AN AMINATED MACROPOROUS RESIN FROM AQUEOUS SOLUTIONS

A macroporous polymeric adsorbent NG-8 was synthesized with divinylbenzene using conventional suspension polymerization technique.Its aminated product NG-9 was prepared by introducing tertiary amino groups into NG-8 for removal of tannin acid from aqueous solutions.NG-9 could be used directly without a wetting process and had higher adsorption capacity than NG-8,which might be attributed to the enhanced adsorbent-adsorbate interaction due to the tertiary amino groups on the polymeric matrix.The Langmuir equation was successfully employed to describe the adsorption process.The adsorption enthalpy change further validated the uptake of tannin acid on NG-9 to be an enhanced physical adsorption because of the Lewis acid-base interaction.In addition,adsorption kinetic studies testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate maybe for the hindrance of the tertiary amino groups and water clusters built up.     

喹烯酮合成工艺的改进

以邻硝基苯胺为起始原料,经过氧化、Beirut反应、缩合反应3步合成产品喹烯酮,总收率73.4%.产品经HPLC分析,质量分数为98.5%.并通过m.P.、IR、1H NMR和13C NMR确证其结构.     

Chaotic bursting lag synchronization of Hindmarsh–Rose system via a single controller

Chaotic bursting lag synchronization of Hindmarsh–Rose system is investigated. Two lag synchronization schemes with only a single controller are proposed to synchronize Hindmarsh–Rose chaotic system via back stepping method. Especially in the second scheme, only one state variable is contained in the controller. Based on Lyapunov stability theory, the sufficient conditions for synchronization are obtained analytically in both cases. Finally, numerical simulations are provided to show the effectiveness of the developed methods.     

Ordering trees with n vertices and matching number q by their largest Laplacian eigenvalues

Denote by T_n,q the set of trees with n vertices and matching number q. Guo [On the Laplacian spectral radius of a tree, Linear Algebra Appl. 368 (2003) 379-385] gave the tree in T_n,q with the greatest value of the largest Laplacian eigenvalue. In this paper, we give another proof of this result. Using our method, we can go further beyond Guo by giving the tree in T_n,q with the second largest value of the largest Laplacian eigenvalue.     

Fluorimetric study of interaction of benzidine with trypsin

The interaction of benzidine (BEN) with trypsin was studied by fluorescence spectrum. It was shown that BEN has quenched the fluorescence launching from trypsin by reacting with it and forming a certain kind of new complex. The quenching and energy transfer mechanisms were discussed. The binding constants and thermodynamic parameters at three different temperatures, the binding locality, and the binding power were obtained. The conformation of trypsin was discussed by synchronous and three-dimensional fluorescence techniques.