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61.
N-Octadecyl-N′-maleoyl-L-phenylalanine(ODMA-L-Phe)was synthesized through the condensation,deprotection and acid- ylation reaction of BOC-L-phenylalauine,octadecylamine and maleic anhydride,ODMA-L-Phe can self-assemble in some organic solvents and turned them into thermally reversible physical supramolecular organogels.The morphology of ODMA-L-Phe aggregates was characterized by polarized optical microscopy(POM)and field emission scanning electron microscope(FE-SEM). The aggregates of ODMA-L-Phe were needle-like fibrils with diameters of approximately 100-200 nm.The mechanism of ODMA- L-Phe serf-assembly in organic solvents was investigated using ~1H NMR and circular dichroism(CD).The results indicated that hydrogen bonding was one of the main driving forces for the self-assembly of ODMA-L-Phe. 相似文献
62.
Photonic band structures of two-dimensional photonic crystals with deformed lattices 总被引:2,自引:0,他引:2 下载免费PDF全文
Using the plane-wave expansion method, we have calculated and analysed the
changes of photonic band structures arising from two kinds of deformed
lattices, including the stretching and shrinking of lattices. The square
lattice with square air holes and the triangular lattice with circular air
holes are both studied. Calculated results show that the change of lattice
size in some special ranges can enlarge the band gap, which depends strongly
on the filling factor of air holes in photonic crystals; and besides, the
asymmetric band edges will appear with the broken symmetry of lattices. 相似文献
63.
Zu‐Shun Xu Zi‐Wei Deng Xiao‐Xi Hu Lei Li Chang‐Feng Yi 《Journal of polymer science. Part A, Polymer chemistry》2005,43(11):2368-2376
Monodisperse polystyrene microspheres with diameters of 200–500 nm were prepared by dispersion polymerization with microwave irradiation with poly(N‐vinylpyrrolidone) as a steric stabilizer and 2,2′‐azobisisobutyronitrile as a radical initiator in an ethanol/water medium. The morphology, size, and size distribution of the polystyrene microspheres were characterized with transmission electron microscopy and photon correlation spectroscopy, and the formed films of the polystyrene dispersions were characterized with atomic force microscopy. The effects of the monomer concentration, stabilizer concentration, and initiator concentration on the size and size distribution of the polystyrene microspheres were investigated. The polystyrene microspheres prepared by dispersion polymerization with microwave irradiation were smaller, more uniform, and steadier than those obtained with conventional heating. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2368‐2376, 2005 相似文献
64.
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66.
Journal of Optimization Theory and Applications - In this paper, we investigate an inexact quasisubgradient method with extrapolation for solving a quasiconvex optimization problem with a closed,... 相似文献
67.
Yazhen Wang Rifang Li Hongge Jia Guoxing Yang Yutao Di Chenxi Xu Liqun Ma Hui Zhang Yongli Zhou Yu Zang Shuangping Xu Zhaoyang Sun Liwu Zu Chenge Yue Tianyu Lan 《Chemical Papers》2018,72(11):2871-2877
A novel peroxy group-containing silane coupling agent was synthesized and anchored on the surface of titanium dioxide nanoparticles (nano-TiO2) to form an immobilized-initiator-modified nano-TiO2 species. In this study, the kinetic parameters of the peroxy group-containing silane were tested and assessed using DSC. The pre-exponential factor (Ad) was 8.973?×?108 and the activation energy (Ea) was 80.736 kJ mol?1. Moreover, the empirical Arrhenius equation was determined to be ln Kd?=???80.736/RT?+?ln(8.973?×?108). To obtain continuous polymers, acrylonitrile (AN) and methyl methacrylate (MMA) were polymerized using the novel peroxy group-containing silane and FeSO4 as an initiator system. The number average molecular weights (Mn of PAN?=?3×104 and Mn of PMMA?=?1.4?×?105) and polydispersity indexes (PDI of PAN?=?2.76 and PDI of PMMA?=?1.65) were determined by GPC. It was suggested that the redox initiation system can generate highly reactive species on the surfaces of inorganic nanoparticles. The nano-TiO2-grafted polymers were successfully obtained. 相似文献
68.
大气丙酮碳同位素组成测定方法的研究 总被引:1,自引:0,他引:1
利用气相色谱/燃烧/同位素比值质谱(GC/C/IRMS)分析技术,研究了具有不同碳同位素组成的丙酮与衍生剂2,4-二硝基苯肼(DNPH)的液相反应及其相应的气相反应实验过程中的碳同位素效应,探讨了以该方法测定大气丙酮碳同位素组成的可行性。研究结果表明,在衍生化过程中不会产生碳同位素分馏。本实验通过测定衍生剂DNPH与相应的衍生物的碳同位素值,大气中丙酮碳同位素组成通过质量平衡方程计算而求得。采用该方法对大气丙酮碳同位素组成的初步测定结果表明,具有相同排放源的大气丙酮碳同位素比值基本不变。本方法实验重现性好,测定精度高,可以用于分析大气丙酮的排放源研究。 相似文献
69.
GAO Hong-Xu ZHAO Feng-Qi HU Rong-Zu ZHANG Hai DONG Hai-Shan YAO Pu XU Zhou HU Gang 《中国化学》2008,26(11):1973-1978
The thermal behaviour and decomposition reaction kinetics of benzotrifuroxan (BTF) were determined by TG and DSC techniques. The kinetic parameters of the exothermic decomposition reaction in a temperature programmed mode (the apparent activation energy Ea and pre-exponential factor A) were calculated by a single non-isothermal DSC curve. The E values calculated using the Kissinger and Flynn-Wall-Ozawa equations and integral isoconversional non-linear equations were used to check the validity of activation energy by a single non-isothermal DSC curve. The results show that the kinetic model function in integral form and the values of Ea and A of the decomposition reaction of BTFare , 109.95 kJ•mol-1 and 108.16 s-1, respectively. The values of ∆S≠, ∆H≠ and ∆G≠ of this reaction are -93.15 J•mol-1•K-1, 150.72 kJ•mol-1 and 153.15 kJ•mol-1, respectively. The critical temperature of thermal explosion of BTF is 257.33 ℃. 相似文献
70.
N-Octadecyl-N1-maleoyl-L-phenylalanine (ODMA-L-Phe) was synthesized through the condensation, deprotection and acid- ylation reaction of BOC-L-phenylalanine, octadecylamine and maleic anhydride. ODMA-L-Phe can self-assemble in some organic solvents and turned them into thermally reversible physical supramolecular organogels. The morphology of ODMA-L-Phe aggregates was characterized by polarized optical microscopy (POM) and field emission scanning electron microscope (FE-SEM). The aggregates of ODMA-L-Phe were needle-like fibrils with diameters of approximately 100-200 nm. The mechanism of ODMA- L-Phe self-assembly in organic solvents was investigated using XH NMR and circular dichroism (CD). The results indicated that hydrogen bonding was one of the main driving forces for the self-assembly of ODMA-L-Phe. 相似文献