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101.
Jing Gao Yingwu Luo Rui Wang Bogeng Li Shiping Zhu 《Journal of polymer science. Part A, Polymer chemistry》2007,45(14):3098-3111
The RAFT (co)polymerization kinetics of methyl methacrylate (MMA) and n‐butyl acrylate (BA) mediated by 2‐cyanoprop‐2‐yl dithiobenzoate was studied with various RAFT concentrations and monomer compositions. The homopolymerization of MMA gave the highest rate. Increasing the BA fraction fBA dramatically decreased the copolymerization rate. The rate reached the lowest point at fMMA ~ 0.2. This observation is in sharp contrast to the conventional RAFT‐free copolymerization, where BA homopolymerization gave the highest rate and the copolymerization rate decreased monotonously with increasing fMMA. This peculiar phenomenon can be explained by the RAFT retardation effect. The RAFT copolymerization rate can be described by 〈Rp〉/〈Rp〉0 = (1 + 2(〈kc〉/〈kt〉)〈K〉)[RAFT]0)?0.5, where 〈Rp〉0 is the RAFT‐free copolymerization rate and 〈K〉 is the apparent addition–fragmentation equilibrium coefficient. A theoretical expression of 〈K〉 based on a terminal model of addition and fragmentation reactions was derived and successfully applied to predict the RAFT copolymerization kinetics with the rate parameters obtained from the homopolymerization systems. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3098–3111, 2007 相似文献
102.
Santiago Faucher Shiping Zhu 《Journal of polymer science. Part A, Polymer chemistry》2007,45(4):553-565
Atom transfer radical polymerization (ATRP) is a controlled/living radical polymerization process developed a decade ago that allows the synthesis of tailored macromolecules. It has been widely used in the laboratory for polymer synthesis since but little use has been made of it at the industrial scale for polymer production. This is due to the low activity of the ATRP catalyst that is central to the process. Much work has been done over the years to overcome this challenge, and the greatest successes have been achieved through catalyst supporting and recycling. We present here a historical account of the development of supported ATRP catalysts while shedding light on their present and future challenges. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 553–565, 2007 相似文献
103.
1 IntroductionIn recent years) there were many results of studying boundary value problemsfor functional differential equations [1-5]. But the boundary conditions are allDirichlet's type. In this paper, we will study a kind of boundary value problemswitb integro boundary condition fOr the functional differential equdtionswhere f(t, yt, x, y) is a continuous real function defined on the set fl = [0, T] xC. x R', and is continuously differentiable with respect to each variable x, y;p E C. = C… 相似文献
104.
Weifeng Liu Kailun Zhang Hong Fan Wen‐Jun Wang Bo‐Geng Li Shiping Zhu 《Journal of polymer science. Part A, Polymer chemistry》2013,51(2):405-414
Living copolymerization of ethylene and 1‐octene was carried out at room temperature using the fluorinated FI‐Ti catalyst system, bis[N‐(3‐methylsalicylidene)‐2,3,4,5,6‐pentafluoroanilinato] TiCl2/dried methylaluminoxane, with various 1‐octene concentrations. The comonomer incorporation up to 32.7 mol % was achieved at the 1‐octene feeding ratio of 0.953. The living feature still retained at such a high comonomer level. The copolymer composition drifting was minor in this living copolymerization system despite of a batch process. It was found that the polymerization heterogeneity had a severe effect on the copolymerization kinetics, with the apparent reactivity ratios in slurry significantly different from those in solution. The reactivity ratios were nearly independent of polymerization temperature in the range of 0–35 °C. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
105.
106.
Hydrophilic Cu3BiS3 Nanoparticles for Computed Tomography Imaging and Photothermal Therapy 下载免费PDF全文
Yan Yang Huixia Wu Benzhao Shi Linlin Guo Yingjian Zhang Xiao An Hao Zhang Shiping Yang 《Particle & Particle Systems Characterization》2015,32(6):668-679
Hydrophilic Cu3BiS3 nanoparticles (NPs) have been prepared using the thermal decomposition of precursor complexes in oily‐mixed solvent followed by coating the produced Cu3BiS3 NPs with polyvinylpyrrolidone (PVP). The resulting Cu3BiS3/PVP NPs remain stable in aqueous solutions over a long period of time, and meanwhile, they show low in vitro cytotoxicity and negligible toxicity to mice in vivo. Cu3BiS3/PVP NPs could operate as an efficient dual‐modal contrast agent to simultaneously enhance X‐ray computed tomography imaging and photothermal imaging of tumor model in vivo. Moreover, highly efficient ablation of cancer cells both in vitro and in vivo has been successfully achieved by combining Cu3BiS3/PVP NPs with near‐infrared (NIR) laser irradiation. All of the positive results in this study highlight that Cu3BiS3/PVP NPs could serve as a promising platform for cancer diagnosis and therapy. 相似文献
107.
针对电站锅炉炉内三维温度场重建问题,基于声学理论构建数学模型.提出两种基于奇异值分解法(Singular Value Decomposition,SVD)的正则化算法,利用少量声学数据,对炉膛火焰分布的几种典型模型进行仿真重建.采用不同标准差的高斯噪声对两种算法的抗噪声能力进行检验.仿真结果表明,正则化SVD算法可以解决严重不适定的重建问题,重建温度场能够准确反映温度场分布,并且算法具有一定的抗噪声能力.TSVD正则化算法重建速度更快,抗噪声能力更强,适用于燃烧情况复杂的电站锅炉. 相似文献
108.
109.
In this work, CO2‐breathing induced reversible activation of mechanophore within microgels is reported. The microgels are prepared through soap‐free emulsion polymerization of CO2‐switchable monomer 2‐(diethylamino)ethyl‐methacrylate, using spiropyran (SP) based mechanophore MA‐SP‐MA as cross‐linker. The microgels can be swollen by CO2 aeration. The swelling of microgels activates the SP mechanophore into merocyanine, causing distinguished color and fluorescence change. Moreover, these transitions are highly reversible, and the initial states of microgels can be easily recovered by “washing off” CO2 with N2. The present contribution represents the first example of CO2‐breathing activation of mechanophore within microgels.
110.