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941.
Interesting complexes containing a mnt2– bridge, based on the reaction of [M(mnt)2]2– [M = Ni or Cu] with [Cu(LH)]+, have been prepared and characterized by e.s.m.s., i.r and u.v–vis. spectroscopic techniques and by electrochemistry. The complexes show weak antiferromagnetic interactions between magnetic centers. The X-ray analysis of the molecular structure of [Cu(LH)]2[Ni(mnt)2] has been completed. It structurally features the CN group of mnt2– which can act as a bridging ligand between two transition metals.  相似文献   
942.
阴离子型层柱材料的插层组装   总被引:10,自引:0,他引:10  
任玲玲  何静  段雪 《化学通报》2001,64(11):686-691
提出插层组装的概念,论述了阴离子型层状材料经插层组装出结构有序的层柱材料,包括层柱材料插层组装途径、插层组装的客体、插层组装的驱动力以组装客体在层间的定位,以及插层组装的发展前景。  相似文献   
943.
The problem of a Griffith crack in an unbounded orthotropic functionally graded material subjected to antipole shear impact was studied. The shear moduli in two directions of the functionally graded material were assumed to vary proportionately as definite gradient. By using integral transforms and dual integral equations, the local dynamic stress field was obtained. The results of dynamic stress intensity factor show that increasing shear moduli’s gradient of FGM or increasing the shear modulus in direction perpendicular to crack surface can restrain the magnitude of dynamic stress intensity factor.  相似文献   
944.
4th-order spline wavelets on a bounded interval   总被引:1,自引:0,他引:1  
IntroductionWaveletanalysishasexperiencedanenormousdevelopmentinrecentyears.Oneoftheimportantfieldsisthenumericalanalysisofdifferentialequations.Theadvantageofadoptingwaveletshasbeenreported[1~ 4].Classicalapproachestowaveletconstructiondealwithmultireso…  相似文献   
945.
头盔用复合材料抗侵彻性能研究进展   总被引:5,自引:0,他引:5  
对头盔用复合材料抗冲击性能的研究及其主要成果进行了总结和评述,包括所用材料的冲击动力学性能、头盔结构在冲击下的损伤和破坏特点、其能量吸收机制的理论分析和数值模拟等几方面,提出了一些亟待深入的研究方向.  相似文献   
946.
从发展复合肥料出发,研究了CaSO-Ca(H2PO4)2H2O体系及其三元边界体系Ca(H2PO4)2-CO(NH2)2-H2Od 25℃时的等温溶度,三元体系中形成一个新化合物Ca(H2PO4)2。CO(NH2)2。四元体系溶 度图可以指导商品普钙磷肥转化为含各合复肥。  相似文献   
947.
A study of growth of barium hydrogen phosphate (BaHPO4) crystal from solution is reported. The raw materials of barium hydrogen phosphate were successfully synthesized through chemical reaction in water. The solubility in HCl and H3PO4 solution were studied. It increased when acid concentration and temperature become higher, and the fitted curve of solubility is nearly a line. The acid concentration affects crystalline morphology of BaHPO4 crystal. The crystallization is well when the acid solution ranges from 0.5 to 0.8M. © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim  相似文献   
948.
An exact solution of Fisher equation and its stability   总被引:1,自引:0,他引:1       下载免费PDF全文
段文山  杨红娟  石玉仁 《中国物理》2006,15(7):1414-1417
In this paper, the Fisher equation is analysed. One of its travelling wave solution is obtained by comparing it with KdV--Burgers (KdVB) equation. Its amplitude, width and speed are investigated. The instability for the higher order disturbances to the solution of the Fisher equation is also studied.  相似文献   
949.
Mutations in leucine-rich repeat kinase 2 (LRRK2) are recognized as the most frequent cause of Parkinson’s disease (PD). As a multidomain ROCO protein, LRRK2 is characterized by the presence of both a Ras-of-complex (ROC) GTPase domain and a kinase domain connected through the C-terminal of an ROC domain (COR). The bienzymatic ROC–COR–kinase catalytic triad indicated the potential role of GTPase domain in regulating kinase activity. However, as a functional GTPase, the detailed intrinsic regulation of the ROC activation cycle remains poorly understood. Here, combining extensive molecular dynamics simulations and Markov state models, we disclosed the dynamic structural rearrangement of ROC’s homodimer during nucleotide turnover. Our study revealed the coupling between dimerization extent and nucleotide-binding state, indicating a nucleotide-dependent dimerization-based activation scheme adopted by ROC GTPase. Furthermore, inspired by the well-known R1441C/G/H PD-relevant mutations within the ROC domain, we illuminated the potential allosteric molecular mechanism for its pathogenetic effects through enabling faster interconversion between inactive and active states, thus trapping ROC in a prolonged activated state, while the implicated allostery could provide further guidance for identification of regulatory allosteric pockets on the ROC complex. Our investigations illuminated the thermodynamics and kinetics of ROC homodimer during nucleotide-dependent activation for the first time and provided guidance for further exploiting ROC as therapeutic targets for controlling LRRK2 functionality in PD treatment.  相似文献   
950.
The electron density profile peaking and the impurity accumulation in the HL-2A tokamak plasma are observed when three kinds of fuelling methods are separately used at different fuelling particle locations. The density profile becomes more peaked when the line-averaged electron density approaches the Greenwald density limit nG and, consequently, impurity accumulation is often observed. A linear increase regime in the density range ne< 0.6nG and a saturation regime in ne > 0.6nG are obtained. There is no significant difference in achieved density peaking factor fne between the supersonic molecular beam injection (SMBI) and gas puffing into the plasma main chamber. However, the achieved fne is relatively low, in particular, in the case of density below 0.7nG, when the working gas is puffed into the divertor chamber. A discharge with a density as high as 1.2nG, i.e. ne = 1.2nG, can be achieved by SMBI just after siliconization as a wall conditioning. The metallic impurities, such as iron and chromium, also increase remarkably when the impurity accumulation happens. The mechanism behind the density peaking and impurity accumulation is studied by investigating both the density peaking factor versus the effective collisionality and the radiation peaking versus density peaking.  相似文献   
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