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171.
Qin Lou Matthew A. Kishpaugh Devon A. Shipp 《Journal of polymer science. Part A, Polymer chemistry》2010,48(4):943-951
The synthesis of statistical and block copolymers, consisting of monomers often used as resist materials in photolithography, using reversible addition‐fragmentation chain transfer (RAFT) polymerization is reported. Methacrylate and acrylate monomers with norbornyl and adamantyl moieties were polymerized using both dithioester and trithiocarbonate RAFT agents. Block copolymers containing such monomers were made with poly(methyl acrylate) and polystyrene macro‐RAFT agents. In addition to have the ability to control molecular weight, polydispersity, and allow block copolymer formation, the polymers made via RAFT polymerization required end‐group removal to avoid complications during the photolithography. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 943–951, 2010 相似文献
172.
Abstract
Nicotinamide crystallizes with 3-hydroxy-2-naphthoic acid and 4-aminobenzoic acid to give rise to cocrystal 1 and 2, respectively. Cocrystal 1, [C11H8O3][C6H6N2O], crystallizes in the monoclinic space group C2/c with a = 25.810(4), b = 4.8932(5), c = 23.869(4) ?, β = 107.078(8)o, V = 2881.6(7) ?3, Z = 8, C17H14N2O4, M r = 310.30, D c = 1.431 g/cm3. Cocrystal 2, [C7H7NO2][C6H6N2O]·H2O, crystallizes in the triclinic space group P-1 with a = 7.214(5), b = 7.326(5), c = 13.484(11) ?, α = 83.23(2), β = 77.189(18), γ = 80.35(2)o, V = 682.7(9) ?3, Z = 2, C13H15N3O4, M r = 277.28, D c = 1.349 g/cm3. Similar carboxylic acid···pyridine synthon R 22(7) can be observed in the two cocrystals. In 1, amide of nicotinamide forms a C(4) chain from the anti H to its carbonyl oxygen. In 2, the amide forms a R 22(8) homodimer which is linked into 2D layer by water molecule through different hydrogen-bonding interactions. The 3D hydrogen-bonded structure results from a synthon R 42(8) from amide, water and amino group of 4-aminobenzoic acid. 相似文献173.
The multi-linear variable separation approach is reviewed in this article. The method has been recently established and successfully
solved a large number of nonlinear systems. One of the most exciting findings is that the basic multi-linear variable separation
solution can be expressed by a universal formula including two (1+1)-dimensional functions, and at least one is arbitrary
for integrable systems. Furthermore, the method has been extended in two different ways so as to enroll more low dimensional
functions in the solution.
相似文献
174.
Considering the wavelength characteristics of the pump high-power laser diode, a modified Fabry-Perot fiber laser resonator is designed. And a fiber laser with more than 10Watts output, near diffraction-limited and operating in the 1110nm region is developed. 相似文献
175.
Bendong Lou 《Journal of statistical physics》2003,110(1-2):377-383
We study singular limit of a p-Laplacian reaction-diffusion equation with a spatially inhomogeneous reaction term. The coefficient of the reaction term is much larger than the diffusion coefficient and sharp interfaces appear between two phases. We show by matched asymptotic expansions that the limit equation (interface equation) is a mean curvature flow with drift terms, similar to the case p = 2. 相似文献
176.
177.
云南甘草中齐墩果烷型五环三萜化合物的NMR谱的研究 总被引:2,自引:1,他引:1
本文研究了云南甘草皂甙元(glyyunnansapogenin)等oleanane类化合物的核磁共振谱。运用PBB,INEPT,DEPT方法,并结合化学位移值规律归属了这些化合物的13C-NMR信号。总结出用角甲基的化学位移植范围判定角甲基的取代位置的方法,分析了角甲基被氧取代后对环的化学位移值的影响。按类似olean-12-en,18α-H方式考虑,归属了oleana-11,13(18)-diene化合物的13C-NMR信号。讨论了具30→18β内酯或2929→18α内酯类化合物的核磁谱规律。另外,还发现了DE环上有1个OAC取代时,与其偕碳质子的化学位移值规律。 相似文献
178.
Abstract– We have observed transient changes in the curvature of purple membrane fragments upon photoexcitation as a function of the pH of the suspending medium. The room temperature suspensions have low ionic strengths, and the bending is observed by changes in the scattered light at 320 nm. The photoexcitation is from a 20 ns laser pulse at 532 nm. We use a simple first-order approximation to subtract any changes in the scattered light associated with transient absorption changes during the photocycle. The resultant scattering curves are then fitted to the sum of three fundamental bending processes. Each process has an exponential rise, an exponential decay and an amplitude. We model two of the processes as transient forces correlated with the charge motion during the photocycle. The third process is probably cuased by local changes in the pH as the protein pumps protons. However, this is not proved rigorously. Additional experiments are proposed. 相似文献
179.
We introduce H-fields as ordered differential fields of a certain kind. Hardy fields extending , as well as the field of logarithmic-exponential series over are H-fields. We study Liouville extensions in the category of H-fields, as a step towards a model theory of H-fields. The main result is that an H-field has at most two Liouville closures.
Received: 15 November 1999 / in final form: 19 December 2000 / Published online: 1 February 2002 相似文献
180.
准分子激光束的喇曼组束 总被引:5,自引:3,他引:2
受激喇曼散射可以将紫外准分子激光辐射频移到特定的近紫外或可见光波长,采用喇曼整形技术可以改善斯托克斯光的光束质量,本文报道喇曼组束提高喇曼整形效率的实验结果. 相似文献