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961.
The topic of this work is the generalized X- and Y-functions of multidimensional radiative transfer. The physical problem considered is spatially varying, collimated radiation incident on the upper boundary of an isotropically scattering, plane-parallel medium. An integral transform is used to reduce the three-dimensional transport equation to a one-dimensional form, and a modified Ambarzumian's method is used to derive coupled, integro-differential equations for the source functions at the boundaries of the medium. The resulting equations are said to be in double-integral form because the integration is over both angular variables. Numerical results are presented to illustrate the computational characteristics of the formulation.  相似文献   
962.
A combination of ring opening metathesis polymerization (ROMP) and click chemistry approach is first time utilized in the preparation of 3‐miktoarm star terpolymer. The bromide end‐functionality of monotelechelic poly(N‐butyl oxanorbornene imide) (PNBONI‐Br) is first transformed to azide and then reacted with polystyrene‐b‐poly(methyl methacrylate) copolymer with alkyne at the junction point (PS‐b‐PMMA‐alkyne) via click chemistry strategy, producing PS‐PMMA‐PNBONI 3‐miktoarm star terpolymer. PNBONI‐Br was prepared by ROMP of N‐butyl oxanorbornene imide (NBONI) 1 in the presence of (Z)‐but‐2‐ene‐1,4‐diyl bis(2‐bromopropanoate) 2 as terminating agent. PS‐b‐PMMA‐alkyne copolymer was prepared successively via nitroxide‐mediated radical polymerization (NMP) of St and atom transfer radical polymerization (ATRP) of MMA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 497–504, 2009  相似文献   
963.
No difference in the actual gel points was substantially observed among three isomeric diallyl phthalates such as diallyl phthalate (DAP), diallyl isophthalate, and diallyl terephthalate (DAT); this interesting gelation behavior was discussed further in terms of the correlation between gelation and the difference in cyclization modes, and also, the difference in reactivity between the uncyclized and cyclized radicals for cross‐linking. In the present work, we tried to extend the preceding discussion to the polymerization of triallyl trimellitate (TAT) because the molecular structure of TAT is presumed to essentially involve the characteristics of three isomeric diallyl phthalates and, therefore, the enhanced gelation was expected in TAT polymerization. However, no enhancement of gelation was observed. For a full understanding of the gelation in multiallyl cross‐linking polymerization, we explored further the polymerizations of DAP, DAT, and TAT, especially focusing on the characterization of resultant network polymer precursors (NPPs) using SEC‐MALLS‐viscometry providing the correlation of [η] versus Mw of fractionated samples. Notably, the structure of NPP consisting of oligomeric primary polymer chains generated from specific allyl polymerization would become core‐shell type dendritic with the progress of polymerization. The correlation between delayed gelation and decreased reactivity of dendritic NPP for intermolecular cross‐linking is discussed. Conclusively, the reactivity for intermolecular cross‐linking between NPPs decreased with the progress of polymerization leading to a delayed gelation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2871–2881, 2009  相似文献   
964.
在KMT多重散射理论框架下,应用动量空间一级光学势,基于Franco和Yin关于核子-核子散射振幅的相随动量转移而改变的建议,研究了入射能量为1GeV时的质子-4He弹性散射. 发现这个相改变使得KMT类型的理论计算的微分散射截面和极化本领与实验符合得更好.  相似文献   
965.
966.
We have studied the acoustic waves in the (0 0 1) and (1 1 0) surfaces of AlN, GaN and InN. We have employed the surface Green function matching method and different sets of calculated elastic constants available in the literature for these materials, because no experimental values are available. Important differences are found for the velocities of the bulk and surface acoustic waves coming from these sets of elastic constants, in such a way that they could be easily measured by ultrasonic and Brillouin techniques. These results together with the expressions obtained here for the velocities of the acoustic waves in high symmetry directions could be used to determine the elastic coefficients of these materials.  相似文献   
967.
We study the scattering of vortices in the Abelian (2+1)-dimensional Higgs model. We show that in the case of the symmetric head-on collision of N vortices, their trajectories are rotated by the angle π/N after the collision. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 156, No. 1, pp. 77–91, July, 2008.  相似文献   
968.
The use of palladium catalysts derived from 1,1′‐bis‐diisopropylphosphino‐ferrocene and a microwave heating source allows the coupling of a range of ortho‐substituted aryl bromides to diphenylphosphine derivatives to proceed in good yield in under 30 min. Optimization studies reveal that the combination of diphenylphosphine and DABCO is superior to more basic phosphide nucleophiles such as Ph2PK or Ph2PMgBr. High yields are only observed when moderately bulky electron rich diphosphines are used as ligands. The differences between P? C coupling and other cross‐coupling reactions are discussed in the light of the reactivity observed. Studies aimed at producing industrially important 1,2‐bis‐phosphino‐benzene ligands are also described. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
969.
The broad range of interface light scattering investigations in recent years shows the power and the versatility of these techniques to address new and open questions in colloid and interface science and the soft condensed matter field. Structural information for polymers, liquid crystals, or colloids close to planar or spherical colloidal interfaces are either captured with long range light scattering resolution, or in a complementary approach by high resolution ellipsometric techniques. Of special interest is the dynamic behavior close to or in interfaces, since it determines material properties and responses to external fields. Due to the broad dynamical range and the high scattering contrast for visible light, interface light scattering is a key to elucidate soft matter interfacial dynamics. This contribution reviews experimental and related theoretical approaches for interface light scattering and further gives an overview of achievements based on such techniques.  相似文献   
970.
Based on the quark-gluon structure of nucleon and the existence of Odderon in nucleon via gluon selfinteraction, the elastic scattering of pp at high energies is studied. Our theoretical predictions reproduce experimental data perfectly. The contributions from individual terms of quark-quark, gluon-gluon interactions, quark-gluon interference and the Odderon terms to total cross section are analyzed. In addition to the leading quark-quark contribution, the Odderon contribution is quite important. In particular, the Odderon plays an essential role in fitting to data. Therefore, We may claim that the high energy pp and pp elastic scattering may be good processes to search for the Odderon, the three Reggeized gluon bound states.  相似文献   
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