聚硫橡胶对环氧胶粘剂的增韧作用研究

环氧树脂以其优良的粘接性、化学稳定性、工艺性等性能,在粘接、涂料、机械、电子、国防等领域有广泛的应用[1].环氧树脂改性及工艺研究的相关报道较多[2-9].环氧树脂固化后有脆性大的缺点,在一定程度上限制了环氧树脂的应用.采用液体橡胶增韧环氧胶是改善环氧胶脆性的有效途径.本文介绍了采用聚硫橡胶增韧环氧胶的方法,并且研究了增韧后环氧胶的力学性能.     

油酸新戊二醇己二酸复合酯的合成及其润滑性能

新戊二醇(NPG)和己二酸(AA)通过酯化反应合成了"低聚物"中间体(1).当n(NPG):n(AA)＝1.5～3.0时,1的聚合度(m)在4.34～2.10,收率97%.以对甲苯磺酸为催化剂,甲苯为带水剂,1与油酸进行酯化得到复合酯(2),收率83%～89%.测定了2的黏度、黏度指数、氧化稳定性、生物降解率、摩擦磨损性能和热稳定性.结果表明,2的黏度和氧化稳定性随着m的增大而增大,100 ℃时的黏度在18.3 mm~2·s~(-1)～30.1 mm~2·s~(-1),黏度指数均超过200,凝点低于-43 ℃,生物降解率＞96%,最大无卡咬负荷(P_B)为784 N,磨斑直径0.40 mm,热分解温度＞300 ℃.1和2的结构经IR表征.     

Synthesis and Crystal Structure of Unprecedented Pentanuclear Cu_5~Ⅱ Complex Containing both Macrocyclic and Azido Ligands

The organic-inorganic hybrid complex with formula [(CuL)2Cu3(μ-1,1-N3)4(ClO4)2],complex 1,{CuL,[5,6:14,15-dibenzo-1,4,8,12-tetraazacyclopentadeca-7,13-diene-2,3-dione(2-)]copper(II)},has been synthesized and structurally determined. The crystals of complex 1 crystallize in the triclinic system with space group P1,a=0.92983(12) nm,b=1.09644(14) nm,c=1.27396(16) nm,α=70.782(2)°,β=86.266(2)°,γ=78.284(2)°. In this com-plex,the five copper ions are bridged by macrocyclic oxamide groups and azido. Furthermore,C―H...     

多元校正流动注射电位滴定法同时测定苯甲酸和山梨酸

将流动注射应用于酸碱电位滴定分析,建立了一种可同时测定混合有机酸的电位滴定新方法。在该方法中,用氢氧化钠与氯化钾的混合溶液作为滴定剂,在流通池中同时插入pH指示电极和氯离子指示电极,在滴定过程中的任一滴定点,流出液的pH值和酸碱的混合比例可由两个电极的电位测定值同时获得,从而可应用多元校正法由相应的滴定曲线求得混合酸中每一种组分的含量。该方法不仅免去了体积和时间读数,而且减少了试剂和样品的消耗量,分析速度快。应用该方法对混合样品中的苯甲酸和水杨酸进行同时测定,其相对标准偏差分别为0．19％～0．37％,回收率分别为97．3％～102．6％。     

矩阵方程$X A^*X^{-q}A=Q~(q\geq 1)$的Hermite正定解

In this paper, Hermitian positive definite solutions of the nonlinear matrix equation X ＋ A^＊X^-qA = Q （q≥1） are studied. Some new necessary and sufficient conditions for the existence of solutions are obtained. Two iterative methods are presented to compute the smallest and the quasi largest positive definite solutions, and the convergence analysis is also given. The theoretical results are illustrated by numerical examples.     

Independent research and development progress in large-scale wind turbine blade with coordinated aerodynamics,structure, and load

Abstract According to the three key elements in blade design process, i.e., aerodynamic design, structure design, and load prediction, the independent research and development (R&D) progress of blade design is summarized and analyzed. The calculational fluid dynamics (CFD) method, the vortex method, and the blade element momentum method (BEM) are described. Based on the widely used BEM method, the solutions for the blade design in low-speed wind area are obtained. A brief overview of the traditional design and analysis methods based on beam models is given. The defects of these methods used for simulating the structure of large-scale composite blade are analyzed. The application progress of the finite element method (FEM) used in the blade structure analysis is shown. The effects of load prediction on the blades and entire wind turbine are introduced. The progress in load forecasting is described. With the analysis of the relationship among these three key elements, it is concluded that developing a blade optimization design system with coordinated aerodynamics, structure, and load will truly meet the requirement of high efficiency and low cost. The main directions for further study are pointed out, e.g., high efficiency and low load airfoils, structural nonlinear finite element analysis, aerodynamic structure coupling research, and establishing different design standards. The aim is to establish a blade R&D system suitable for the conditions of wind resources in China and promote the development of wind power in the country.     

2,5-二酮哌嗪衍生物的一锅法合成及其细胞毒活性

以DMF为溶剂,Cs₂CO₃为碱, N,N-二乙酰基-2,5-二酮哌嗪,芳醛和卤代烷经一锅法合成了１10个2,5-二酮哌嗪类衍生物（4a~4j,其中4c, 4f和4i为新化合物）,收率54.2％～75.7％,其结构经¹H NMR, ¹³C NMR和ESI-MS确证。生物活性研究结果表明：（Z）-1-乙酰基-3-（1-亚甲基萘）-4-烯丙基-2,5-二酮哌嗪（4c）对U937, Hela和Du145等细胞具有一定的细胞毒活性。     

流延法制备铌酸钾钠基无铅压电陶瓷的性能研究

通过流延成型技术,以片状K0.5Na0.5NbO3(简称为KNN)粉体为模板,结合掺杂改性后的基料粉体(K0.45Na0.55)0.98Li0.02(Nb0.77Ta0.18Sb0.05)O3-0.005BaZrO3(简称为KNNLST-BZ)流延制备出KNN基无铅压电陶瓷,研究了不同的工艺参数(烧结温度、烧结次数)对于KNNLST-BZ织构化陶瓷的电学性能、显微结构的影响.结果表明:模板含量为20wt;的KNNLST-BZ织构化陶瓷在1145℃下保温2h呈现出优异的性能:压电常数d33=204 pC/N,横向机电耦合系数k31=23;,剩余极化强度Pr=26 μC/cm2,矫顽场Ee=1.2 kV/mm.同时该织构化陶瓷在1145℃下烧结2次能得到更优的电学性能:d33 =248 pC/N,k31=32.54;,Pr=38 μC/cm2,Ec=1.2 kV/mm,介电损耗tanδ=6.38;,机械品质因数Qm=16.76,介电常数εT33/ε0=913.7,横向伸缩振动频率常数N1=2244.     

Zn1-xMgxZrNb2O8微波介质陶瓷的结构与性能研究

采用传统的固相反应合成法制备了Zn1-xMgx ZrNb2O8(x=0-0.4)微波介质陶瓷.研究了Mg2+的取代量x对Zn1-xMgxZrNb2O8陶瓷的烧结特性、物相组成、显微结构以及微波介电性能的影响.结果表明:Zn1-xMgxZrNb2O8陶瓷的烧结温度随着Mg2+取代量x的增加,略有提升;当x=0-0.3时,体系形成了单相的(Zn,Mg) ZrNb2O8固溶体,而当x=0.4时,体系除了形成(Zn,Mg) ZrNb2O8固溶体外,还有少量未知杂相生成;随着Mg2+的取代量的增加,Zn1-xMgxZrNb2O8陶瓷的微波介电性能呈现不同的变化规律.当x=0.2时,组分为Zn0.8Mg0.2ZrNb2O8的陶瓷在1230℃烧结4h,可获得较佳的微波介电性能:εr=27.55,Q ×f=58731 GHz,τf=-66.7×10-6/℃.     

分子动力学研究F1-ATP合酶对三磷酸腺苷的稳定和定位作用

F₁-ATP合酶通过与ATP之间建立广泛的相互作用,实现对ATP的位置进行精确的定位.这些相互作用为ATP的合成/水解创造了稳定的环境.理解这些相互作用是理解ATP的合成/水解机理的基础.我们通过分子动力学模拟方法研究这些相互作用,找出在稳定化过程中起到重要作用的残基.通过检测ATP和F₁-ATP合酶之间的非键相互作用,发现残基段158-164所形成的loop区域及残基R189, Y345对ATP存在显著相互作用.其中,该loop区域对ATP的三磷酸部分形成一个半包围结构,封闭活性位点区域,并通过氢键网络约束ATP三磷酸的运动,为ATP合成/水解创造稳定的环境.此外,关键残基Y345通过π-π叠加相互作用对ATP的碱基进行约束,但是ATP的碱基可以在平行于Y345芳香环的平面内进行滑动,我们推断这种滑动运动有利于促进ATP的水解.