气相中自由基OH在不同催化剂下对甲酰氟FCHO进行提氢反应的理论性研究

分别在水、甲酸和硫酸存在的情况下,通过CCSD(T)//M06-2X/6-311++G(3df,3pd)的理论方法,对大气中自由基OH提取甲酰氟FCHO上的氢进行了反应机理和动力学的研究.计算结果表明相对于反应物,加入催化剂的过渡态的能垒从3.64 kcal/mol分别下降到-2.89、-6.25和-7.76 kcal/mol,表明水、甲酸和硫酸在甲酰氟FCHO和自由基OH提氢反应中起了重要作用.通过运用具有Eckart隧道校正的传统过渡态理论计算出的动力学数据表明通道X...FCHO+OH(X=H₂O, HCOOH,或者H₂SO₄)要比通道X...OH+FCHO更有利于反应的发生.催化剂水、甲酸和硫酸的加入使甲酰氟FCHO 和自由基OH提氢反应的速率常数要比不加催化剂时小,说明了催化剂的加入不能促进大气中甲酰氟FCHO和自由基OH的反应.     

Molecular Dynamics Simulation of the Binding Interaction between Hormone Glucagon Protein and Self-Assembled Monolayer Molecules

Restrained molecular dynamics simulations were performed to study the binding affinity of the peptide with alkanethiols of different tail-groups, S（CH2）7CH3, S（CH2）7OH and S（CH2）7COOH, which self-assembled on Au（111） surface in the presence of water molecules. The curves of binding affinity were calculated by fixing the center of mass of the peptide at various distances from the assembling surface. Simulation results show that the binding affin- ity is in the order as COOH-SAMs〉OH-SAMs〉CH3-SAMs, while 100% COOH-SAMs〉5% COOH-SAMS in concentration. The effects on binding affinity by different tail-groups were also studied. Results show that the binding affinity between COOH-SAMs and the peptide is bigger than those of the others and increasing the acidity of COOH-SAMs will result in stronger attractive power.     

荧光法研究药物分子与人血清白蛋白的结合作用

本文应用荧光光谱和能量转移技术首次研究了心血管病药物盐酸地尔硫卓、盐酸川芎嗪和甘草酸三种药物分子与人血清白蛋白的结合作用。研究结果表明, 盐酸川芎嗪和盐酸地尔硫卓在溶液中与白蛋白形成缔合物, 荧光猝灭机理符合静态机制, 缔合物的稳定常数分别为: 盐酸川芎嗪Ks=1.12×10^4(mol/L)^-^1(25℃),Ks=6.95×10^3 (mol/L)^-^1(40℃); 盐酸地尔硫卓Ks=4.71×10^2(mol/L)^-^1(25℃), Ks=3.00×10^2(mol/L)^-^1(40℃)。甘草酸与白蛋白的作用符合动态猝灭机理, 动态猝灭常数为Kd=4.76×10^(mol/L)^-^1(25℃), Kd=6.19×10^2(mol/L)^-^1(40℃)。基于Forster 偶极-偶极无辐射能量转移机理确定了药物分子盐酸川芎嗪在人血清白蛋白中与第214位色氨酸残基之间的距离R=1.76nm(25℃), R=1.80nm(40℃)。     

苯甲酰氧基取代的2-吡喃酮的固相光二聚反应

以二苯甲酮为光敏化剂,C4-位苯甲酰氧基取代的6-甲基-2-吡喃酮(1)的固相光二聚反应穿过1的C3-C4双键高选择性地发生[2+2]环加成反应合成了anti头-头二聚物(2),其结构经1H NMR,FI-IR,MS和元素分析表征。反应机理利用WINMOPAC PM5方法推定。     

5-Fluorouracil derivatives ⅩⅩⅢ. Synthesis and antitumor activities of 1-carbamoyl-5-fluorouracils having aromatic ring

In order to get good antitumor agents especially better than 5-fluorouracil,tegafur and l-hexylcarbamoyl-5-fluorouracil (HCFU),fourty nine 1-carbamoyl-5-fluorouracil having aromatic ring were synthesized from 5-fluorouracil and isocyanates or amines.Antitumor activity was tested in the L-1210 tumor system,and 5 compounds gave better value of therapeutic ratio than 5-fluorouracil,tegafur,HCFU.l-(4-Methoxybenzylcarbamoyl)-5-fluorouracil gave the best result.     

弱还原气氛下水稻秸秆对晋城无烟煤的助熔机理

以高灰熔点的晋城无烟煤和水稻秸秆为研究对象,通过CaO-Al_2O_3-SiO_2三元相图、X射线衍射分析(XRD)和扫描电镜耦合X射线能谱分析(SEM-EDX)研究了弱还原气氛下水稻秸秆对晋城无烟煤的助熔机理。随着水稻秸秆添加比例的增加,灰熔融特征温度呈下降趋势,灰中碱性氧化物CaO、Na_2O和K_2O含量增多,结渣指数Rb/a值在0.20-0.69;当水稻秸秆添加量为20%(质量分数)时,流动温度(FT)降低至1 369℃,可满足气化炉液态排渣的要求;水稻秸秆的添加降低了灰中液相出现的温度,增加了液相物质出现的比例和几率,使灰更易发生熔融;混合灰中所形成的钠长石等低熔点矿物质以及钙长石、石英和莫来石所形成的低温共熔物导致灰熔点降低。     

Solution of Klein-Gordon Equation for Pseudo-Coulomb Potential Plus a New Ring-Shaped Potential

Under the condition of an equal mixing of vector and scalar potentials, exact solutions of bound states of the Klein-Gordon equation with pseudo-Coulomb potential plus a new ring-shaped potential are presented. Simultaneously, energy spectrum equations are also obtained. It is shown that the radial equation and angular wave functions are expressed by confluent hypergeogetric and hypergeogetric functions respectively.     

电场作用下CaS的分子结构和电子光谱

以6-311++G(d,p)为基组,采用密度泛函的B3LYP方法优化得到不同外电场(-0·03—0·045a.u.)下CaS分子的基态结构参数、电偶极矩μ、电荷分布、HOMO能级、LUMO能级、能隙、红外光谱和谐振频率等.结果表明,随着正向电场的增加,分子结构与外电场有着强烈的依赖关系,且对电场方向的依赖呈现出不对称性,基态键长和分子偶极矩μ先减小后增大,在F=0·02a.u.时,键长Re取最小值0·2289nm,电偶极矩取最小值1·5969D,HOMO能级和LUMO能级处于先增大后减小,能隙始终是减小的,占据轨道的电子容易激发到空轨道.外电场对CaS分子的激发能和振子强度有较大的影响,这为进一步研究它的电致发光机理提供了一定的理论基础.     

H-酸用作痕量铜的催化测定

在环保化学中痕量铜的分析受到了很大的注意。催化法对较简单和纯材料中微量铜的测定有着重要的实用意义,特别是与近代色谱技术等联合应用,解决了许多痕量杂质的分析问题。利用某些有机物质的催化氧化体系以测定痕量铜,文献中报导很多。我们观察到8-氨基萘酚-3,6-二磺酸(H-酸)在空气中可被氧化成红色产物,但反应速度甚为缓慢。若在碱性介质中有痕量铜离子存在时,在适当温度下其氧化反应速度则大为加快。本文研究其作为催化测定铜的新指示反应的各项条件和应用。结果表明,本     

ACTA PHOTONICA SINICA

本文采用有效折射率方法对Ti扩散Er