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941.
Morphology-controllable platinum nanostructures could be obtained by modulating the growth kinetics in oleylamine. The nanostructures evolve from spherical particles to branched networks with decreasing reaction temperature, and the complexity of the branched-network nanostructures increases with the extended reaction period. Size-dependent magnetic properties and enhanced ferromagnetism in dodecanethiol-capped Pt branched nanostructures indicate that the permanent magnetic moments are probably introduced by broken symmetry and charge transfer because charge transfers more effectively from dodecanethiol than from oleylamine. 相似文献
942.
以多孔Al2O3陶瓷为基体材料, 采用浸渍法担载NiO后用2B铅笔修饰NiO/Al2O3表面, 通过化学镀法沉积约5 μm厚的金属钯, 还原后成功制得Pd/Pencil/Ni/Al2O3膜. 为进行对比, 还制备了未担载镍的Pd/Pencil/Al2O3膜. 膜的表面和断面形貌分别采用扫描电镜和金相显微镜观测, 膜的透氢动力学通过H2/N2单气体法测试, 并以成分为H2 77.8%, CO 5.2%, CO2 13.5%和CH4 3.5%的原料氢测定了膜的氢分离效果. 结果表明, 未载镍的Pd/Pencil/Al2O3膜只具有氢分离作用, 而Pd/Pencil/Ni/Al2O3膜还可以有效地将钯膜泄漏的CO和CO2转化为甲烷, 因而成为双功能型钯膜. 这种双功能膜尤其适用于面向质子交换膜燃料电池(PEMFC)的氢气分离, 既有效解决了PEMFC对氢燃料中CO格外敏感的难题, 又提高了对钯膜缺陷的容忍度, 因而延长了钯膜的使用寿命. 相似文献
943.
Enzymes are macromolecular biological catalysts which can accelerate chemical reactions in living organisms. Almost all the physiological metabolism activities in the cell need enzymes to sustain life via rapid catalysis. Currently, medical research has proved that abnormal enzyme activity is associated with numerous diseases, such as Parkinson’s disease (PD), Alzheimer's disease (AD) and cancers. On the other hand, early diagnosis of those diseases is of great significance to improve the survival rate and cure rate. In the current diagnostic tools, two-photon fluorescent probes (TPFPs) are developing rapidly due to their unique advantages, such as higher spatial resolution, deeper imaging depth, and lower biotoxicity. Therefore, the design and synthesis of two-photon (TP) small molecule enzymatic probes have broad prospects for early diagnosis and treatment of diseases. As of now, scientists have developed many TP small molecule enzymatic probes. This review aims to summarize the TP small molecule enzymatic probes and expound the reaction mechanism. 相似文献
944.
945.
Dr. Ya‐Guang Sun Tian‐Yi Lv Xin Gao Gang Xiong Di Sun Ling‐Ling He Zhen‐He Xu Shu‐Ju Wang Fu Ding 《无机化学与普通化学杂志》2012,638(14):2365-2369
Three new lanthanide‐organic coordination polymers, {[Ln2(bpdc)2(H2O)6(NO3)] · NO3} [Ln = La ( 1 ), Ce ( 2 ), Pr ( 3 )] (H2bpdc = 2, 2′‐bipyridine‐6, 6′‐dicarboxylic acid) were synthesized under hydrothermal conditions and structurally characterized by elemental analysis, IR spectroscopy as well as single‐crystal and powder X‐ray diffraction. Single‐crystal X‐ray diffraction analysis revealed that compounds 1 – 3 are isostructural, composed of two dimensional honeycomb network linked by bpdc ligands. The magnetic property of compound 3 was investigated. 相似文献
946.
采用温和条件下的溶胶-凝胶技术,成功制备了阴离子交换-反相混合模式硅胶基质毛细管电色谱整体柱.通过调整反应液中不同前体的比例,优化了整体柱的制备条件.通过扫瞄电镜,对柱床进行了表征和分析.实验发现,所制备的整体柱电渗流的方向和大小可随流动相pH值的改变而改变,在酸性和中性条件下,具有从阴极流向阳极的电渗流;当流动相pH值升至约7.5时,电渗流方向发生了反转(由阳极流向阴极).在优化的实验条件下,用所制备的整体柱对所考察的酸性(中性)化合物实现了快速分离,并获得了高达160,000 N/m的柱效. 相似文献
947.
A mild, simple process for the effective deoximation of a wide range of ketoximes and aldoximes has been developed, which utilizes available NaNO(2) as the catalyst and molecular oxygen as the green oxidant. Notably Amberlyst-15, which acts as the initiator of NaNO(2), can be reused without regeneration. This environmentally benign protocol could provide a valuable synthetic method for practical applications. 相似文献
948.
949.
The complex stability constants (K(S)), standard molar enthalpy (DeltaH degrees), and entropy changes (DeltaS degrees) for the inclusion complexation of two families of beta-cyclodextrin (beta-CD) dimers, i.e. beta-CD dimers Se1-Se4 bearing 2,2'-diselenobis(benzoyl) tether (Se-dimers) and beta-CD dimers Py1-Py4 bearing 2,2'-bipyridine-4,4'-dicarboxy tether (Py-dimers), with four bile salt guests, i.e. sodium cholate (CA), sodium deoxycholate (DCA), sodium glycocholate (GCA), and sodium taurocholate (TCA), were determined at 25 degrees C in Tris buffer solution (pH 7.4) at 298.15 K by means of isothermal titration microcalorimetry. The thermodynamic parameters obtained, together with the ROESY spectra of interactions between beta-CD dimers and bile salts, consistently suggest that the length, flexibility, and structure of spacers linking the two beta-CD cavities not only determine the binding modes but also significantly alter the molecular selectivity of beta-CD dimers. 相似文献
950.
Molecular dynamics simulation and density functional theory insight into the cocrystal explosive of hexaazaisowurtzitane/nitroguanidine 下载免费PDF全文
Xiong Ding Rui‐Jun Gou Fu‐De Ren Fa Liu Shu‐Hai Zhang Hong‐Fei Gao 《International journal of quantum chemistry》2016,116(2):88-96
Theoretical methods involving molecular dynamics (MD) simulation and density functional theory were performed to investigate the different molecular ratios, mechanical Properties, structure, trigger bond, and intermolecular interaction of hexaazaisowurtzitane (CL‐20)/nitroguanidine (NQ) cocrystal explosive. Results of MD simulation show that CL‐20 and NQ packed in ratios of 1:1 present the larger binding energy and better mechanical properties than any other molecular ratios, which indicates 1:1 cocrystal can form the stable crystal structure. Shorter length and larger dissociation energy of trigger bond in composite structure than in isolated CL‐20 component suggests that the cocrystal may exhibit less sensitive than CL‐20. Analyses of atoms in molecules, reduced density gradient, and natural bond orbital confirm that intermolecular interactions are mainly derived from a series of weak hydrogen bond and strong vdW forces, involving of NH···O, CH···O, CH···N, O···N, and O···O. Additionally, composite structures of 2 and 3 bringing us more attractive performance will act as a key role in constructing of CL‐20/NQ cocrystal explosive. © 2015 Wiley Periodicals, Inc. 相似文献