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51.
一种合成共轭高分子——聚(N,N—二甲基苯胺)的新方法   总被引:3,自引:3,他引:3  
利用一种新的合成方法,首次合成了侧链带有强推生基力的聚苯衍生物--聚(N,N-二甲基苯胺),初步研究了中间产物的形成及这种固相聚合反应的适宜条件,并通过元素分析、红外、HNMR及紫外光谱对聚合产物进行了结构表征。  相似文献   
52.
A 1-D paddle-wheel copper (II) coordination polymer constructed by 2-nitro-benzene-1,4-di(oxyacetic) acid has been synthesized by hydrothermal reaction,and its crystal structure was determined by X-ray diffraction. The crystal is of triclinic,space group P1 with a=7.7257(12),b=8.3648(13),c=11.5516(18),α=76.654(2),β=82.088(2),γ=63.636(2)o,C20H22Cu2N2O20,Mr=737.48,V=650.27(18)3,Dc=1.883 g/cm3,F(000)=374,μ=1.737 cm-1 and Z=1. The final refinement gave R=0.0345 and wR=0.0995 for 1996 observed reflections with I > 2σ(I). The coordination polymer demonstrates a 1-D microporous structure,and the channel is formed by two NBDOA2-and two Cu2+ ions. The ligand NBDOAH2 displays a good flexible characteristic. The 1-D chains are connected to a 3-D supramolecular network by hydrogen bonds.  相似文献   
53.
The interior Dirichlet problem for Laplace's equation on a plane polygonal region $\Omega$ with boundary $\Gamma$ may be reformulated as a second kind integral equation on $\Gamma$. This equation may be solved by the Nyström method using the composite trapezoidal rule. It is known that if the mesh has $O(n)$ points and is graded appropriately, then $O(1/n^2)$ convergence is obtained for the solution of the integral equation and the associated solution to the Dirichlet problem at any $x\in \Omega$. We present a simple extrapolation scheme which increases these rates of convergence to $O(1/n^4)$ .  相似文献   
54.
We are interested in solving elliptic problems on bounded convex domains by higher order methods using the Richardson extrapolation. The theoretical basis for the application of the Richardson extrapolation is the asymptotic error expansion with a remainder of higher order. Such an expansion has been derived by the method of finite difference, where, in the neighborhood of the boundary one must reject the elementary difference analogs and adopt complex ones. This plight can be changed if we turn to the method of finite elements, where no additional boundary approximation is needed but an easy triangulation is chosen, i.e. the higher order boundary approximation is replaced by a chosen triangulation. Specifically, a global error expansion with a remainder of fourth order can be derived by the linear finite element discretization over a chosen triangulation, which is obtained by decomposing the domain first and then subdividing each subdomain almost uniformly. A fourth order method can thus be constructed by the simplest linear finite element approximation over the chosen triangulation using the Richardson extrapolation.  相似文献   
55.
For the eigenvalue problem on a smooth domain we prove that the Richardson extrapolation increases the accuracy from second to third order for linear finite elements, and from fourth ro fifth order for quadratic finite elements, without modification of the scheme near the boundary.  相似文献   
56.
针对Y型沸石在ZSM-5沸石干胶制备及晶化过程中易于溶解、坍塌的问题,采用葡萄糖在水热处理条件下对Y沸石进行包膜处理,提高了Y沸石在高温、高碱度环境中的稳定性,并采用蒸汽相转化法制备了同时含有Y和ZSM-5的双沸石复合物。对影响沸石复合物形成的因素如Y沸石表面碳包膜改性、凝胶碱度、晶化时间等进行了详细讨论。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅立叶变换红外(FT-IR)、N2吸附-脱附,能谱(EDS)以及NH3-TPD等手段对制备的材料进行了表征。结果表明通过蒸汽相转化法能获得Y和ZSM-5两相共存的双沸石复合物,产物中的ZSM-5沸石相前驱体随蒸汽处理时间的延长逐渐从蠕虫状无定型向纳米多晶ZSM-5沸石转变,纳米多晶聚集体与Y型沸石晶粒之间紧密相连,相互包埋。在异丙苯催化裂化反应中,合成的沸石复合物的活性和稳定性介于Y和ZSM-5之间,优于对应的机械混合物。  相似文献   
57.
An electrowetting-on-dielectric actuator is developed, in which the liquid is sandwiched between top and bottom plates. For the bottom plate, silicon wafer is used as the substrate, the heavily phosphorus-doped polysilicon film is deposited by low pressure chemical vapour deposition as the microelectrode array, and thermally grown SiO2 film as the dielectric layer. The top p/ate is a glass plate covered with transparent and conductive indium tin oxide as the ground electrode. In addition, a Teflon AF1600 film is spun on the surface of both the plates as the hydrophobic layer. The experimental results show that when the gap height between two plates is 133μm, a prototype of the device is capable of creating, transporting, merging and dividing droplets of deionized water in an air environment with a 70V at lOHz voltage pulse. This is also established by simulations using the computational fluidic software of CFD-ACE+.  相似文献   
58.
本文研究了在离体培养水稻花药的条件下,一些因素对于诱导花粉发育为植株的作用,结果表明,基本培养基中除补加生长素外,再补加酵母提取物、水解核酸等,对于提高愈伤组织诱导频率有显著效果,在补加有椰子乳、水解乳蛋白、水解核酸等的培养基中形成的愈伤组织分化根与芽的能力高于对照,培养时温度的高低对愈伤组织的发生与分化也有明显影响,获得了从x—4x不同倍性的花粉植株,对于来自F1花粉的二倍体植株后代进行的遗传学观察表明,它们基本上是整齐一致没有分离的。  相似文献   
59.
A novel 3-D coordination polymer with trimeric copper (I) unit, [Cu(3)(CN)(IN)(2)](n)(IN = isonicotinate), was hydrothermally synthesized by the reaction of Cu(NO(3))(2).3H(2)O with isonicotinic and terephthalic acids. The structure was characterized to be a twofold interpenetrated 3-D coordination network polymer with two-coordinated copper(I). It has a powder SHG efficiency about that of KDP.  相似文献   
60.
杨晨光  阚瑞峰  许振宇  张光乐  刘建国 《物理学报》2014,63(22):223301-223301
在强展宽条件下, 光谱信号二阶导数相互的交叠影响较小, 是一种潜在的反演光谱信息的手段. 本文研究了光谱Voigt线形函数的二阶导数, 得出了其二阶导数全域积分为0的性质, 计算了二阶导数最小值与偶数高阶导数最大值和最小值的解析结果, 并通过数值计算与曲线拟合得出了其极大值位置与零点位置的比例与洛仑兹-多普勒半宽比的关系, 为强展宽下由光谱二阶导数准确反演光谱信息提供了理论基础. 关键词: Voigt函数 二阶导数最小值 零点位置  相似文献   
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