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111.
基于Aguado等人拟合的APW势能面(PES), 运用准经典轨线(QCT)方法, 对反应Li+HF(ν=0, j=0)→LiF+H的动力学性质进行了计算. 主要研究了不同碰撞能条件下的反应截面、转动取向、产物散射角分布和竞争反应模式等. 结果表明, 该反应存在直接提取型和间接插入型两种反应模式, 在低能量下反应以间接插入反应模式为主, 能量大于200 meV时则以直接提取反应为主. 相似文献
112.
G. Allasia R. Besenghi R. Cavoretto A. De Rossi 《Applied mathematics and computation》2011,217(12):5949-5966
A new local algorithm for bivariate interpolation of large sets of scattered and track data is presented. The method, which changes partially depending on the kind of data, is based on the partition of the interpolation domain in a suitable number of parallel strips, and, starting from these, on the construction for any data point of a square neighbourhood containing a convenient number of data points. Then, the well-known modified Shepard’s formula for surface interpolation is applied with some effective improvements. The proposed algorithm is very fast, owing to the optimal nearest neighbour searching, and achieves good accuracy. Computational cost and storage requirements are analyzed. Moreover, the efficiency and reliability of the algorithm are shown by several numerical tests, also performed by Renka’s algorithm for a comparison. 相似文献
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114.
This article summarizes the known methods for calculating the internal resistance of tracked undercarriages. The values of the coefficient of internal resistance for sample tracked vehicles are available in the literature and presented in this paper. Although they are suitable for simple computations, they cannot be used to optimize the energy efficiency of new generation tracked undercarriages. This problem might be solved by the models where every phenomenon leading to energy dissipation during vehicle motion is described by a separate submodel as a function of vehicle speed, track tension, undercarriage layout, design features of the undercarriage components, etc. This kind of model is still missing for vehicles with conventional rubber tracks. The article presents multiple state-of-the-art models describing rolling resistance of road wheels, bending resistance of rubber belts, etc., including the models of belt conveyors resistance. A vast majority of the phenomena discussed herein are described by several incompatible models whose parameters have not yet been determined for conventional rubber tracks. Consequently, in the second and the third part of the article, the authors have undertaken a theoretical and experimental studies on the methods for calculating and optimizing the internal motion resistance of vehicles with conventional rubber tracks. 相似文献
115.
M.S. Child 《Contemporary Physics》2013,54(3):212-221
Monodromy (or once round) is a classical property of integrable dynamical systems in two or more degrees of freedom, which imposes a characteristic pattern on the quantum mechanical eigenvalue distribution. This article explains the connection by showing how the presence of an isolated critical point of the Hamiltonian leads to a classical action function that is multi-valued with respect to energy and angular momentum. Consequently, by the Bohr correspondence principle between actions and quantum numbers, there can be no uniquely defined global system of quantum numbers. Implications for the interpretation of highly excited molecular spectra are brought out by reference to quasi-linear molecules, which transfer one degree of freedom from rotational to vibrational motion during the excitation process. Emphasis is placed on the simplest examples, while a brief resumé of the wide scope of the quantum monodromy phenomenon is given in the final section. 相似文献
116.
R. I. Petrova V. P. Perelygin A. B. Akopova M. M. Gogorjan 《Radiation measurements》1995,25(1-4):329-330
The investigation of the track etching velocity dependence for nuclei with Z50 on pH of the etching solution in the olivine crystals from Marjalahti and Eagle Station meteorites, containing galactic cosmic-ray nuclear tracks and also the crystals from Marjalahti meteorite, calibrated at the UNILAC (GSI, Darmstadt) with 14.17 MeV/N 208Pb nuclei, were performed.
The pH of the etching solution were changed from 7.8 to 9.4. It is shown that the optimal track etch condition were realised at pH of etching solution in the interval from 8.4 to 8.8.
The results of the Galactic cosmic-ray nuclei tracks with Z83 revealed in olivine crystals are presented. They were additionally irradiated at 90% to the surface with accelerated 14 MeV/N 132Xe nuclei. 相似文献
117.
Huanhua Cui Baozhong Dong Xiaowei Tang Risheng Wu Puying Zheng 《Radiation measurements》1995,25(1-4):235-238
Using the 27 kG magnetic field produced by a superconducting solenoid we have searched for trapped magnetic monopoles in a magnetite sample from North China. We hvve scanned the nuclear emulsion both for low ionizing tracks and heavily ionizing tracks, and polycarbonate track detectors for heavily ionizing tracks of magnetic monopoles. We obtained a 90% confidence level upper limit of 1.8×10−26 monopoles per nucleon in the magnetite sample. 相似文献
118.
Nonlinear two-point boundary-value problems (TPBVP) can be reduced to the iterative solution of a sequence of linear problems by means of quasilinearization techniques. Therefore, the efficient solution of linear problems is the key to the efficient solution of nonlinear problems.Among the techniques available for solving linear two-point boundary-value problems, the method of particular solutions (MPS) is particularly attractive in that it employs only one differential system, the original nonhomogeneous system, albeit with different initial conditions. This feature of MPS makes it ideally suitable for implementation on parallel computers in that the following requirements are met: the computational effort is subdivided into separate tasks (particular solutions) assigned to the different processors; the tasks have nearly the same size; there is little intercommunication between the tasks.For the TPBVP, the speedup achievable is ofO(n), wheren is the dimension of the state vector, hence relatively modest for the differential systems of interest in trajectory optimization and guidance. This being the case, we transform the TPBVP into a multi-point boundary-value problem (MPBVP) involvingm time subintervals, withm–1 continuity conditions imposed at the interface of contiguous subintervals. For the MPBVP, the speedup achievable is ofO(mn), hence substantially higher than that achievable for the TPBVP. It reduces toO(m) if the parallelism is implemented only in the time domain and not in the state domain.A drawback of the multi-point approach is that it requires the solution of a large linear algebraic system for the constants of the particular solutions. This drawback can be offset by exploiting the particular nature of the interface conditions: if the vector of constants for the first subinterval is known, the vector of constants for the subsequent subintervals can be obtained with linear transformations. Using decomposition techniques together with the discrete version of MPS, the size of the linear algebraic system for the multi-point case becomes the same as that for the two-point case.Numerical tests on the Intel iPSC/860 computer show that substantial speedup can be achieved via parallel algorithms vis-a-vis sequential algorithms. Therefore, the present technique has considerable interest for real-time trajectory optimization and guidance.Dedicated to the Memory of Professor Jan M. SkowronskiThis paper, based on Refs. 1–3, is a much condensed version of the material contained in these references.The technical assistance of the Research Center on Parallel Computation of Rice University, Houston, Texas is gratefully acknowledged. 相似文献
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120.
A neutron personal dosemeter using CR-39 as a detector and hydrogenated materials as proton converters for fast neutron detection plus an air layer for thermal neutron detection is being developed in our laboratory. To increase the CR-39 response to thermal neutrons, the air converter was substituted with Nylon in some dosemeters. Several dosemeters with these two configurations were mounted on a water-filled phantom and exposed under different incidence angles (0, 30 and 60) to: (i) Three ISO neutron sources (241Am–Be, bare 252Cf and moderated 252Cf with Cd shielding), and (ii) two realistic neutron sources (SIGMA and moderated 252Cf) at the IRSN (Cadarache) facilities. The irradiated detectors were electrochemically etched and evaluated in order to determine their dose equivalent response in terms of Hp(10,α). The results obtained are compared to those obtained from Monte Carlo simulations using the MCNPX code. 相似文献