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991.
Four kinds of poly(ethylene glycol) (PEG) derivatives with the similar backbone and different side groups have been synthesized successfully. When both catecholamine and double bond are tethered to polymer backbone, i.e., the PEG backbone, simultaneously, the polymer can accelerate the curing speed of ethyl α‐cyanoacrylate (commercially available as 502) greatly under the same conditions (the curing time of such system is no more than 5 s). Probably this is due to the autoxidation of catecholamines. Through the redox‐cycling, catecholamines can produce, collect free radicals, and thus initiate the free radical polymerization. Due to the fast‐curing of such material when mixed with α‐cyanoacrylate, we could design and develop a new bicomponent super bioglue used in the dentistry or other bioenvironment requiring super fast settlement for further surgical operations. 相似文献
992.
Haiyang Gao Xiaofang Liu Lixia Pei Qing Wu 《Journal of polymer science. Part A, Polymer chemistry》2010,48(5):1113-1121
Two bis(β‐ketoamino)copper [ArNC(CH3)CHC(CH3)O]2Cu ( 1 , Ar = 2,6‐dimethylphenyl; 2 , Ar = 2,6‐diisopropylphenyl) complexes were synthesized and characterized. Homo‐ and copolymerizations of methyl acrylate (MA) and 1‐hexene with bis(β‐ketoamino)copper(II) complexes activated with methylaluminoxane (MAO) were investigated in detail. MA was polymerized in high conversion (>72%) to produce the syndio‐rich atactic poly(methyl acrylate), but 1‐hexene was not polymerized with copper complexes/MAO. Copolymerizations of MA and 1‐hexene with 1 , 2 /MAO produced acrylate‐enriched copolymers (MA > 80%) with isolated hexenes in the backbone. The calculation of reactivity ratios showed that r(MA) is 8.47 and r(hexene) is near to 0 determined by a Fineman‐Ross method. The polymerization mechanism was discussed, and an insertion‐triggered radical mechanism was also proposed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1113–1121, 2010 相似文献
993.
Chuiming Wan Jianxin Meng Fengjin Zhang Xiaoling Deng Chuangtao Yang 《Solid State Communications》2010,150(31-32):1493-1495
A new blue-emitting phosphor LiCaPO4: Eu2+ was synthesized by solid state reaction at a relatively low temperature of 900 °C. It gives a single intense emission band centering at 470 nm, which corresponds to the 4f65d1→4f7 transition of Eu2+. The dependence of luminescence intensities on Eu2+ concentration was investigated. The phosphor, with a single excitation band extending from 250 to 400 nm, could be efficiently excited by near-ultraviolet light-emitting diodes and is believed to be a promising blue-emitting phosphor for white light-emitting diodes. 相似文献
994.
Tian Lan Huichang Bi Suowen Xu Kang Le Zhiyong Xie Yiwei Liu Heqing Huang 《Biomedical chromatography : BMC》2010,24(10):1075-1083
Sphingosine kinase (SphK) is a key enzyme in modulating the levels of sphingosine 1‐phosphate (S1P) as well as an important enzyme in numerous biological responses. Using C17‐sphingosine as a substrate, we established a rapid, sensitive and highly efficient method for determination of SphK activity by analyzing the product C17‐sphingosine 1‐phosphate (C17‐S1P) using liquid chromatography–tandem mass spectrometry. The standard curve for C17‐S1P was linear over a wide range (10–1000 ng/mL) with correlation coefficient (r2) greater than 0.999. The lower limit of quantification for C17‐S1P was 10 ng/mL. The Km values for C17‐sphingosine and ATP were determined to be 28.17 and 188.5 mM, respectively. More importantly, the SphK activity dramatically increased in cultured HEK 293 cells expressing wild‐type SphK1 as well as cells treated with tumor necrosis factor‐a, a sphingosine kinase activator. In contrast, the SphK activity decreased in cultured HEK 293 cells treated with dimethylsphngosine, a sphingosine kinase inhibitor. In conclusion, this method was sensitive and rapid in the determination of SphK acitivity, providing striking utilities in exploring the sphingosine kinase signaling pathway and screening active compounds targeting SphK activity. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
995.
Co3xNi3−3x(PO4)2·8H2O (x = 1, 0.8, 0.6, 0.4, 0.2, and 0) were synthesized via simple wet chemical reaction and energy saving route method. The final decomposition products of hydrates are corresponding anhydrous tri(cobalt nickel) diphosphates. The metal and water contents of the synthesized hydrates were confirmed by AAS and TG/DTG/DTA techniques, respectively. The observed metal and water contents agree well with the formula of the title compounds. The crystal structures and lattice parameters as well as crystallite sizes of the studied compounds were determined using XRD data. The results from XRD and TG/DTG/DTA techniques confirmed that Co3xNi3−3x(PO4)2·8H2O at all ratios were the single phase. The FTIR spectra of studied compounds were recorded and assigned. The thermal behaviours of single and binary tri(cobalt nickel) diphosphate octahydrates were studied for the first time. The morphologies of the studied compounds were investigated by using the SEM technique. The micrographs of all studied compounds exhibited the thin plated morphology. The surface area and the pore size data of anhydrous forms were measured by N2 adsorption at −190 °C according to the BET method. The anhydrous forms of binary metal phosphate at x = 0.8, Co2.4Ni0.6(PO4)2, exhibits the highest surface area and expects to improve the catalytic activity. 相似文献
996.
Chunxia Ou 《Nonlinear Analysis: Real World Applications》2009,10(5):2652-2658
In this paper, shunting inhibitory cellular neural networks with continuously distributed delays are considered. Without assuming the global Lipschitz conditions of activation functions, some new sufficient conditions for the existence and exponential stability of the almost periodic solutions are established. 相似文献
997.
An investigation of the optical properties of a hydrogenic donor in spherical parabolic quantum dots has been performed by using the matrix diagonalization method. The optical absorption coefficient between the ground (L = 0) and the first excited state (L = 1) have been examined based on the computed energies and wave functions. The results are presented as a function of the incident photon energy for the different values of the confinement strength. These results show the effects of the quantum size and the impurity on the optical absorption coefficient of a donor impurity quantum dot. 相似文献
998.
Xingyu Yang 《NoDEA : Nonlinear Differential Equations and Applications》2011,18(3):273-285
We consider the global attractor for the weakly damped forced KdV equation in Sobolev spaces [(H)\dot]s(T){\dot{H}^s({\mathbf T})}for s < 0. Under the assumption that the external forcing term belongs to [(L)\dot]2(T),{\dot{L}^2({\mathbf T}),} we prove the existence of the global attractor in [(H)\dot]s(T){\dot{H}^s({\mathbf T})} for −1/2 ≤ s < 0, which is identical to the one in [(L)\dot]2(T){\dot{L}^2({\mathbf T})} and thus is compact in H
3(T). The argument is a combination of the I-method and decomposing the solution into two parts, one of which is uniformly bounded
in [(L)\dot]2(T){\dot{L}^2({\mathbf T})} and the other decays exponentially in [(H)\dot]s(T){\dot{H}^s({\mathbf T})}. 相似文献
999.
Standard nonparametric prediction intervals for a future order statistic are obtained by taking the interval between two order statistics of the initial sample. We obtain improved prediction intervals by taking the shortest of two or more standard intervals. 相似文献
1000.
J. Młyńczak K. Kopczyński Z. Mierczyk M. Malinowska P. Osiwiański 《Opto-Electronics Review》2012,20(1):87-90
The paper describes investigation of pulse laser generation in newly developed EAT14 glasses with the use of MALO saturable
absorber. Different initial transmission of the saturable absorbers and different transmission of the output coupler were
investigated. The laser generation was carried out using 976-nm pump wavelength. Comparison of peak powers, slop efficiencies
and thresholds was made with a view to choose the best set of glass and saturable absorber for “eye-safe” microchip laser
range-finder. The generated wavelengths by each sample were measured. 相似文献