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131.
Protein Conformation of a Lattice Model Using Tabu Search 总被引:1,自引:0,他引:1
We apply tabu search techniques to the problem of determining the optimal configuration of a chain of protein sequences on a cubic lattice. The problem under study is difficult to solve because of the large number of possible conformations and enormous amount of computations required. Tabu search is an iterative heuristic procedure which has been shown to be a remarkably effective method for solving combinatorial optimization problems. In this paper, an algorithm is designed for the cubic lattice model using tabu search. The algorithm has been tested on a chain of 27 monomers. Computational results show that our method outperforms previously reported approaches for the same model. 相似文献
132.
133.
为解决高等师范院校物理专业学生的知识结构和实际能力与社会需要明显不相适应的矛盾,我们对四年制物理专业的课程结构进行了全面改革。改革后,毕业生不仅能胜任普通中学或职业中学(职业中专)的教学,而且有能力参与厂矿企业的技术工作,具有更广泛的适应性和更强的竞争力。 相似文献
134.
聚醚醚酮链结构与反应的模型化合物的量子化学研究 总被引:1,自引:1,他引:0
利用AM1方法对聚醚醚酮模型化合物全优化,结果为:芳环平均相互扭转角为33.0度,桥键角117.0-118.0度,其分子结构拓扑图形表明:所有苯环(核)为平面构型,但其内角扭曲;其氢原子对苯环构型无实质性贡献,在更长链的计算中,冻结苯核与氢原子也得出满意结果,根据Mulliken键序与电荷讨论了醚交换与磺化反应。 相似文献
135.
B. M. Dzhagarov N. N. Kruk N. V. Konovalova A. A. Solodunov I. I. Stepuro 《Journal of Applied Spectroscopy》1995,62(2):285-289
Presented at the XV IUPAC Symposium on Photochemistry, Prague, July 17–22, 1994. 相似文献
136.
D. Kast A. Jungclaus K.P. Lieb M. Górska G. de Angelis P.G. Bizzeti A. Dewald C. Fahlander H. Grawe R. Peusquens M. De Poli H. Tiesler 《The European Physical Journal A - Hadrons and Nuclei》1998,3(2):115-128
In the neutron deficient isotopes 104,105In lifetimes of high spin states in the range from 0.5 ps to 600 ps have been measured in a coincidence recoil distance Doppler
shift (RDDS) experiment. By combining the Doppler shift attenuation (DSA) and RDDS methods at few μm flight distances, the
problem of delayed feeding has been avoided and very short lifetimes in the range 0.5–0.8 ps have been determined. Shell model
calculations with strong restrictions for the neutron orbitals reveal good agreement with experimental level energies and
still fair agreement for most measured B(M1) and B(E2) values.
Received: 30 June 1998 相似文献
137.
T. Charitat B. Fourcade 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,1(3):333-336
An o-ring takes spontaneously the shape of a chair when strong enough torsion is applied in its tangent plane. This state
is metastable, since work has to be done on the o-ring to return to the circular shape. We show that this metastable state
exists in a Hamiltonian where curvature and torsion are coupled via an intrinsic curvature term. If the o-ring is constrained to be planar (2d case), this metastable state displays a kink-anti-kink
pair. This state is metastable if the ratio is less than , where C and A are the torsion and the bending elastic constants [#!landau!#]. In three dimensions, our variational approach shows that
. This model can be generalized to the case where the bend is induced by a concentration field which follows the variations
of the curvature.
Received: 27 August 1997 / Revised: 23 October 1997 / Accepted: 12 November 1997 相似文献
138.
Polyethyleneimine (PEIM) samples crosslinked by a commercial epoxy resin (Epon 828) were prepared, and their adsorption capacity for acidic gases was studied. The swelling and deswelling characteristics of the crosslinked samples were also examined as part of this program. Reactivation of these adsorbents could be carried out by heat, or by a combination of heat and treatment in dilute alkalies. 相似文献
139.
Summary We discuss a null experiment to search for the fifth force at ranges around 10 km. It is proposed to use a three-axis gravity
gradiometer to measure the trace of the Earth gravity tensor from a freely falling elevator dropped by a balloon. The main
error sources are considered to some extent.
Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990. 相似文献
140.
Olav Kallenberg 《Stochastic Processes and their Applications》1992,40(2):199-223
From the predictable reduction of a marked point process to Poisson, we derive a similar reduction theorem for purely discontinuous martingales to processes with independent increments. Both results are then used to examine the existence of stochastic integrals with respect to stable Lévy processes, and to prove a variety of time change representations for such integrals. The Knight phenomenon, where possibly dependent but orthogonal processes become independent after individual time changes, emerges as a general principle. 相似文献