几种改进的CoMFA方法比较研究血小板活化因子拮抗剂

由于传统的比较分子场分析(CoMFA)方法本身存在一些缺陷，使得分子的叠合 规则以及叠合分子的空间取向和空间位置等因素对q~2的影响很大，因此相继提出 了几种改进的CoMFA方法。为了优化CoMFA结果，应用传统的CoMFA方法和交叉验证 的R~2引导的区域选择法(q~2-GRS)、全取向搜索法（AOS）、全空间搜索法（APS） 以及比较分子相似性指数(CoMSIA)等四种改进的CoMFA方法，对18个pinusolide类 衍生物这类新发现的血小板活化因子（PAF）拮抗剂进行了比较研究。结果表明四 种改进的CoMFA方法得到的q~2值均比传统CoMFA的高。q~2-GRS方法得到的q~2值有 所提高，但综合结果并不理想，AOS与APS得到的q~2较为理想，而在CoMSIA中， q~2几乎不受空间取向或空间位置的影响。同时我们引人基于样本的偏最小二乘法 （SAMPLS）取代原AOS／APS程序中的传统PLS进行统计分析，明显提高了其运行速 度。最后，根据q~2最高的CoMFA模型和CoMSIA模型设计了几个预测活性更高的 pinusolide类似物。     

二维铁电材料ABP2X6内在极高的负泊松比

Recently, ferroelectric materials have attracted considerable research attention. In particular, two dimensional (2D) ferroelectric materials have been considered as most crucial for next-generation circuit designs because of their application as novel electric memory devices. However, a 2D ferroelectric material is very rare. The ferroelectric materials with the form ABP₂X₆ (A = Ag, Cu; B = Bi, In; X = S, Se) are of interest because of their ferroelectric property maintained in their ultrathin structures. Within the ABP₂X₆ monolayer, the P―P bonds form the pillars that hold the top and bottom X planes, while the off-center A―B atoms between the X layers induce a spontaneous ferroelectric polarization. If the two off-center A―B sites are equally aligned, this would lead to the appearance of the paraelectric state. Such intriguing structures must impart novel mechanical properties to the materials. Until now, there has been no report on the mechanical properties of monolayer ABP₂X₆. Based on first-principles calculations, we studied the structural, electronic, mechanical as well as the electromechanical coupling properties of monolayer ABP₂X₆ (A = Ag, Cu; B = Bi, In; X = S, Se). We found that they are all semiconductors with wide bandgaps of 2.73, 2.17, 3.00, and 2.31 eV for CuInP₂Se₆, CuBiP₂Se₆, AgBiP₂S₆, and AgBiP₂Se₆, respectively, which are calculated based on the Heyd-Scuseria-Ernzerhof (HSE) exchange correlation functional model. The conduction band minimum is mainly from p orbitals of X and B atoms, whereas the valence band maximum is due to the hybridization of the p orbital of X atoms and the d orbital of A atoms. Moreover, there are three short and three long A/B―X bonds due to the A―B off-center displacement. Together with the d-p orbital hybridization, the main reason for the distorted ferroelectric structure in ABP₂X₆ monolayers is the Jahn-Teller effect. ABP₂X₆ monolayers are predicted to be a new class of auxetic materials with an out-of-plane negative Poisson's ratio, i.e., the values of the negative Poisson's ratio are in the order AgBiP₂S₆ (−0.805) < AgBiP₂Se₆ (−0.778) < CuBiP₂Se₆ (−0.670) < CuInP₂S₆ (−0.060). This is mainly due to the tensile strain applied in the x/y direction enlarging the angle between P―P bonds and top layer X atoms, thereby enhancing the bucking height of monolayer ABP₂X₆. Moreover, external strain has a significant impact on the A―B off-center displacement, rendering an out-of-plane piezoelectric polarization. The values of e₁₃ for CuInP₂S₆, CuBiP₂Se₆, AgBiP₂S₆, AgBiP₂Se₆ monolayers are calculated to be −3.95 × 10⁻¹², −5.68 × 10⁻¹², −3.94 × 10⁻¹², −2.71 × 10⁻¹² C∙m⁻¹, respectively, which are comparable to the only experimentally confirmed 2D out-of-plane piezoelectric Janus system (piezoelectric coefficient = −3.8 × 10⁻¹² C∙m⁻¹). This unusual auxetic behavior, ferroelectric polarization, and the electromechanical coupling in monolayer ABP₂X₆ could potentially lead to enormous technologically important applications in nanoelectronics, nanomechanics, and piezoelectrics.     

An Oscillation Condition for an Electrode－separated Piezoelectric Sensor in Non－electrolyte Liquid

ＡｎＯｓｃｉｌｌａｔｉｏｎＣｏｎｄｉｔｉｏｎｆｏｒａｎＥｌｅｃｔｒｏｄｅ－ｓｅｐａｒａｔｅｄＰｉｅｚｏｅｌｅｃｔｒｉｃＳｅｎｓｏｒｉｎＮｏｎ－ｅｌｅｃｔｒｏｌｙｔｅＬｉｑｕｉｄＳＨＥＮＤａ－ｚｈｏｎｇ，ＨＵＡＮＧＭｉｎｇ－ｓｈａｎ，ＬＩＮＳｏｎｇ，Ｎ...     

Time-Resolved Photoluminescence Spectra of Porous Si

Ｔｉｍｅ－ＲｅｓｏｌｖｅｄＰｈｏｔｏｌｕｍｉｎｅｓｃｅｎｃｅＳｐｅｃｔｒａｏｆＰｏｒｏｕｓＳｉＦＥＩＨａｏ－ｓｈｅｎｇ，ＨＡＮＬｉ，ＣＨＥＹａｎ－ｌｏｎｇ，ＮＩＥＲｕｉ－ｊｕａｎａｎｄＬＩＴｉｅ－ｊｉｎ（ＤｅｐａｒｒｍｅｎｔｏｆＰｈｙｓｉｃｓａｎｄＤ...     

KIO4氧化茜素红催化荧光法测定痕量铁（Ⅲ）

ＫＩＯ＿４氧化茜素红催化荧光法测定痕量铁（Ⅲ）俞英，聂瑞华，黄坚锋，谢世涛（南昌大学应用化学研究所机电系，南昌，３３００４７）关键词催化荧光法，茜素红，铁（Ⅲ）茜素红主要作为光度法测定铝、铍的试剂［１，２］，我们曾用其催化荧光测定痕量钒［３］．进一步...     

RAFT聚合法合成聚丙烯酰胺基偶氮苯的研究

以二硫代苯甲酸苄酯(BDTB)为链转移剂,偶氮二异丁腈(AIBN)为引发剂,丙烯酰胺基偶氮苯(AAAB)为单体,DMF为溶剂,利用可逆加成-断裂链转移(RAFT)聚合法合成了聚丙烯酰胺基偶氮苯(PAAAB),并考察了聚合温度和链转移剂浓度对聚合反应的影响。通过FT-IR、1 H-NMR、GPC等对链转移剂和聚合物结构进行了表征。结果表明:聚合反应动力学曲线呈良好的线性关系,分子量分布窄;随着[BDTB]/[AIBN]比例的增大,聚合速率和分子量下降,分子量分布变窄。     

固态光聚合反应研究进展

光引发的固态聚合反应一直是令人感兴趣的研究领域.本文综述了固态光聚合的研究进展.着重介绍了双炔类体系,二烯类体系以及(甲基)丙烯酸酯体系的固态光聚合的研究工作以及应用前景.     

硫掺杂氧化锡纳米材料的固相合成及其可见光降解百草枯

以十二烷基苯磺酸钠(SDBS)为模板, 采用低温固相反应法合成了硫掺杂二氧化锡(S-SnO₂)纳米粉体材料, 并用XRD、XPS、SEM、UV-Vis、FTIR及HR-TEM等技术对材料进行了表征, 探讨了S掺杂SnO₂纳米材料对百草枯的可见光降解性能, 分析了S掺杂效应的作用机理。结果表明, 采用固相反应法所得SnO₂及S-SnO₂纳米材料的禁带宽度变窄, SDBS对材料的表面结构具有一定的调控作用。S是以S(Ⅳ)和S(Ⅵ)的形式进入SnO₂晶格形成Sn_1-xS_xO₂晶体结构而不是进入SnO₂晶格间隙, Sn-O-S键的弯曲振动峰介于930~980 cm^-1之间。S的掺杂使SnO₂纳米材料表面活性增强, 光催化降解百草枯的活性依次为SnO₂ 2(SDBS) 2 2(SDBS), 2 h内, S-SnO_2(SDBS)样品对除草剂百草枯的光催化活性达95.2%, 其主要原因是S-SnO_2(SDBS)材料表面有更多的羟基和进入SnO₂晶格的S, 有利光生电荷的有效分离。     

基于柔性多羧酸配体H3TCOPM构筑的Co(Ⅱ)配合物的合成与结构

以三苯甲烷-4,4’,4"-三羧酸（H₃TCOPM）为主配体,以含氮二齿配体4,4’-bipyridine（4,4’-bipy）为辅助配体,与Co（NO₃）₂·6H₂O通过溶剂热反应得到了2个配位聚合物{[Co₂（α-OH-TCOPM）（OH）（H₂O）₄]·DMF}_n（1）（α-OH-H₃TCOPM=三苯甲醇-4,4’,4"-三羧酸）和{[Co₃（α-OH-TCOPM）₂（4,4’-bipy）₃（H₂O）₆]·2H₂O}_n（2）。晶体结构分析表明,配合物1为四边形的二维层状结构,而配合物2为二维网状结构。采用红外光谱、粉末X射线衍射对配合物进行了表征,用热重分析仪研究了其热稳定性。     

Synthesis,Crystal Structure,and Biological Activity of 4-Chlorobenzaldehyde (2-trifluoromethylTrifluoromethyl-5,6,7,8-tetrahydrobenzo[4 ,5]-thieno[2,3-d]pyrimidin-4-yl)hydrazone Monohydrate

The novel title compound 4-chlorobenzaldehyde (2-trifluoromethyl-5,6,7,8- tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-yl)hydrazone monohydrate (C18H14ClF3N4SH2O, Mr = 428.86) has been synthesized by a condensation reaction of 4-chlorobenzaldehyde with (2-trifluoromethyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-yl)hydrazine, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a = 7.4252(7), b = 26.344(2), c = 10.3095(9) , = 109.407(2)°, V = 1902.0(3) 3 , Z = 4, Dc = 1.498 g/cm3 , μ = 0.356 mm-1 , F(000) = 880, the final R = 0.0564 and wR = 0.1681 for 2343 observed reflections with I > 2 (I). X-ray diffraction analysis reveals that the title hydrazone molecule is nearly planar except for the cyclohexene and trifluoromethyl moieties. In the crystal packing, the molecules form stacks by a three-dimensional framework, which results from intermolecular N(3)-H(3)···O(1), O(1)-H(1B)···N(2), O(1)- H(1B)···N(4) and O(1)-H(1A)···F(1) hydrogen bonds via water molecules together with π-π stacking interactions. Molecular geometry of the title compound in the ground state optimized by B3LYP functional with 6-311G** basis sets indicates that the calculations are in agreement with the experimental data. The preliminary bioassay suggested that the title compound exhibits relatively good fungicidal activity against Fusarium oxysporium f.sp.vasinfectum and Dothiorella gregaria.