共查询到20条相似文献,搜索用时 31 毫秒
1.
E. A. Gomin V. D. Davidenko A. S. Zinchenko I. K. Kharchenko 《Physics of Atomic Nuclei》2017,80(8):1399-1407
The KIR computer code intended for calculations of nuclear reactor kinetics using the Monte Carlo method is described. The algorithm implemented in the code is described in detail. Some results of test calculations are given. 相似文献
2.
The computer code DECAY4 is developed to generate initial-energy, time, and angular distributions of particles emitted in radioactive decays of nuclides and in nuclear (atomic) deexcitations. Data for describing nuclear-and atomic-decay schemes are taken from the ENSDF and EADL database libraries. By way of example, the DECAY4 code is applied to describing several underground experiments. 相似文献
3.
This paper presents an efficient algorithm to cancel the parallel interference for multiuser detection (MUD) schemes in code division multiple access (CDMA) based 20.48 Gb/s optical multiple input multiple output orthogonal frequency division multiplexing (O-MIMO-OFDM) system over 1200 km of standard single mode fiber (SSMF). The performance of the system is compared by simulation results using the efficient algorithm and minimum mean square error (MMSE) schemes. It shows the superior performance of efficient algorithm. 相似文献
4.
Based on the light nucleus reaction model (Nucl. Sci. Eng. l33 (1999) 218), four aspects (neutron incident energy region, reaction channel analysis, the renewed level schemes and the optical model parameters) of n 12 C reaction are improved to calculate total outgoing neutron double-differential cross sections with modified LUNF code below 30 MeV. The calculated results agree fairly well with the experimental data at En = 14.1 MeV and 18 MeV. The analysis shows that the pre-equilibrium mechanism, which is exactly considered the conservation of energy, momentum and parity, dominates the whole reaction process. The contribution of the neutron emission from 5He to total energyangular spectra is also considered properly. This modified LUNF code will be a useful tool to set up the file of neutron double-differential cross sections below 30 MeV in the neutron evaluation nuclear data library. 相似文献
5.
SUN Xiao-Jun DUAN Jun-Feng WANG Ji-Min ZItANG Jing-Shang 《理论物理通讯》2007,48(3):534-540
Based on the light nucleus reaction model (Nucl. Sci. Eng. 133 (1999) 218), four aspects (neutron incident energy region, reaction channel analysis, the renewed level schemes and the optical model parameters) of n+ ^12 C reaction are improved to calculate total outgoing neutron double-dilferential cross sections with modified LUNF code below 30 MeV. The calculated results agree fairly well with the experimental data at En = 14.1 MeV and 18 MeV. The analysis shows that the pre-equilibrium mechanism, which is exactly considered the conservation of energy, momentum and parity, dominates the whole reaction process. The contribution of the neutron emission from 5He to total energy- angular spectra is also considered properly. This modified LUNF code will be a useful tool to set up the file of neutron double-differential crass sections below 30 Me V in the neutron evaluation nuclear data library. 相似文献
6.
高速水声通信系统仿真研究 总被引:10,自引:1,他引:9
水声信道是较复杂的数据通信环境。本文设计了3种高速水声通信的系统结构,并通过系统的、全面的仿真比较了他们的性能。建立了包括时变衰落、多途和加性干扰的水声信道模型。3种方案都采用相位相干的QPSK调制技术,接收端采用空时联合的自适应均衡(内置DPLL)接收;前向纠错编码译码器分别采用3种方案:卷积码,串行级联码(卷积码+RS码),并行级联卷积码(Turbo码)。通过仿真研究了不同数目水声接收机的接收分集下的系统性能,研究了3种编码方案下的系统性能。 相似文献
7.
《Nuclear Physics A》1988,481(2):189-206
Extensive and complete nuclear level schemes and neutron resonance densities of 75 nuclides have been used to determine parameters of level density formulae, the spacing distribution of levels with equal spins and parities, and spacing correlations. The dependences of the level density parameters on A, on pairing energies and on shell effects are discussed. The spacing distribution is found to lie between a Poisson and Wigner distribution indicating a transitional character between regular and chaotic properties of the nuclear quantum system near the ground state. 相似文献
8.
《Journal of computational physics》2008,227(1):400-430
We present a new numerical algorithm for the solution of coupled collisional and collisionless systems, based on the block structured adaptive mesh and time refinement strategy (AMR). We describe the issues associated with the discretization of the system equations and the synchronization of the numerical solution on the hierarchy of grid levels. We implement a code based on a higher order, conservative and directionally unsplit Godunov’s method for hydrodynamics; a symmetric, time centered modified symplectic scheme for collisionless component; and a multilevel, multigrid relaxation algorithm for the elliptic equation coupling the two components. Numerical results that illustrate the accuracy of the code and the relative merit of various implemented schemes are also presented. 相似文献
9.
PANDA是上海核工程研究设计院研发的压水堆组件计算程序。该程序采用基于特征线方法(MOC)的一步化计算流程,即在不引入能群压缩和栅元均匀化的情况下直接进行组件层面的两维非均匀输运计算。多群数据库采用基于ENDF/B-VI制作的70群结构中子数据库,基于ENDF/B-VII的新版数据库也正在开发中。共振自屏计算采用了空间相关丹可夫方法(SDDM),既具备燃料芯块分区计算的能力,又保留了传统Stammler方法的计算效率。多群非均匀输运计算采用二维模块化MOC方法,并辅以双重粗网有限差分(CMFD)加速技术,具有良好的计算精度和效率。对传统线性子链解析(TTA)方法以及多种矩阵指数方法进行了研究,选取了适合PANDA程序燃耗链的燃耗方程求解技术。基于以上基本模型开发了PANDA程序,并从程序模块、总体集成和核设计程序系统确认等三个层面,初步验证了PANDA程序的计算性能,表明了PANDA程序的工程设计计算能力。 相似文献
10.
PANDA是上海核工程研究设计院研发的压水堆组件计算程序。该程序采用基于特征线方法(MOC)的一步化计算流程,即在不引入能群压缩和栅元均匀化的情况下直接进行组件层面的两维非均匀输运计算。多群数据库采用基于ENDF/B-VI制作的70群结构中子数据库,基于ENDF/B-VII的新版数据库也正在开发中。共振自屏计算采用了空间相关丹可夫方法(SDDM),既具备燃料芯块分区计算的能力,又保留了传统Stammler方法的计算效率。多群非均匀输运计算采用二维模块化MOC方法,并辅以双重粗网有限差分(CMFD)加速技术,具有良好的计算精度和效率。对传统线性子链解析(TTA)方法以及多种矩阵指数方法进行了研究,选取了适合PANDA程序燃耗链的燃耗方程求解技术。基于以上基本模型开发了PANDA程序,并从程序模块、总体集成和核设计程序系统确认等三个层面,初步验证了PANDA程序的计算性能,表明了PANDA程序的工程设计计算能力。 相似文献
11.
The cross-sections for the formation of 54,56,57,58Co in the 54,56,57,58Fe(p, n) reaction from threshold to 30 MeV protons have been theoretically calculated using the TALYS-1.4 nuclear model code, whereby we have studied major nuclear reaction mechanisms, including direct, pre-equilibrium and compound nuclear reaction. Subsequently, the level density and shell damping parameters have been adjusted and at the same time, the odd–even effects are well comprehended. The excitation functions have been compared with experimental nuclear data. It is observed that the theoretical cross-sections match fairly well. Proton-induced reaction cross-sections provide clues to understand the nuclear structure and offers a good testing ground for ideas about nuclear forces. In addition, complete information in this field is very much required for application in accelerator-driven subcritical system. 相似文献
12.
It is one of the most important contents to analyze the energy level structure in the nuclear physics. At present the high-spin state of the odd-A nuclear 143Pm have been investigated by using heavy-ion beam reaction the excitation energy level 8.4MeV and spin (47/2) (h=1) has been obtained. In this paper, according to the principle of the nuclear shell model and experiment information ,the 143Pm nuclear structure has been analyzed with 2 interaction potentials and to the weak-coupling model(WCM) result,especially explore the sequences of γ-ray transitions,which depend to the corresponding dominant configuration. The program OXBASH code is adopted. 相似文献
13.
We study a 3-dimensional, dual-field, fully explicit method for the solution of Maxwell's equations in the time domain on unstructured, tetrahedral grids. The algorithm uses the element level time domain (ELTD) discretization of the electric and magnetic vector wave equations. In particular, the suitability of the method for the numerical analysis of nanometer structured systems in the optical region of the electromagnetic spectrum is investigated. The details of the theory and its implementation as a computer code are introduced and its convergence behavior as well as conditions for stable time domain integration is examined. Here, we restrict ourselves to non-dispersive dielectric material properties since dielectric dispersion will be treated in a subsequent paper. Analytically solvable problems are analyzed in order to benchmark the method. Eventually, a dielectric microlens is considered to demonstrate the potential of the method. A flexible method of 2nd order accuracy is obtained that is applicable to a wide range of nano-optical configurations and can be a serious competitor to more conventional finite difference time domain schemes which operate only on hexahedral grids. The ELTD scheme can resolve geometries with a wide span of characteristic length scales and with the appropriate level of detail, using small tetrahedra where delicate, physically relevant details must be modeled. 相似文献
14.
15.
Evaluating the accuracy performance of Lucas-Kanade algorithm in the circumstance of PIV application
《中国科学:物理学 力学 天文学(英文版)》2015,(10)
Lucas-Kanade(LK) algorithm, usually used in optical flow filed, has recently received increasing attention from PIV community due to its advanced calculation efficiency by GPU acceleration. Although applications of this algorithm are continuously emerging,a systematic performance evaluation is still lacking. This forms the primary aim of the present work. Three warping schemes in the family of LK algorithm: forward/inverse/symmetric warping, are evaluated in a prototype flow of a hierarchy of multiple two-dimensional vortices. Second-order Newton descent is also considered here. The accuracy efficiency of all these LK variants are investigated under a large domain of various influential parameters. It is found that the constant displacement constraint, which is a necessary building block for GPU acceleration, is the most critical issue in affecting LK algorithm's accuracy, which can be somehow ameliorated by using second-order Newton descent. Moreover, symmetric warping outbids the other two warping schemes in accuracy level, robustness to noise, convergence speed and tolerance to displacement gradient, and might be the first choice when applying LK algorithm to PIV measurement. 相似文献
16.
We report the realization, using nuclear magnetic resonance techniques, of the first quantum computer that reliably executes a complete algorithm in the presence of strong decoherence. The computer is based on a quantum error avoidance code that protects against a class of multiple-qubit errors. The code stores two decoherence-free logical qubits in four noisy physical qubits. The computer successfully executes Grover's search algorithm in the presence of arbitrarily strong engineered decoherence. A control computer with no decoherence protection consistently fails under the same conditions. 相似文献
17.
18.
ZHANG Jingfu XIE Jingyi DENG Zhiwei & LU Zhiheng Key Laboratory for Quantum Information Measurements Department of Physics Tsinghua University Beijing China Center for Quantum Information Tsinghua University Beijing China Department of Materials Science Engineering Beijing Normal University Beijing China Testing Analytical Center Beijing Normal University Beijing China Department of Physics Beijing Normal University Beijing China 《中国科学G辑(英文版)》2005,48(1):57-67
Dense coding using superpositions of Bell-states is proposed. The generalized Grover's algorithm is used to prepare the initial entangled states, and the reverse process of the quantum algorithm is used to determine the entangled state in the decoding measurement. Compared with the previous schemes, the superpositions of two Bell-states are exploited. Our scheme is demonstrated using a nuclear magnetic resonance (NMR) quantum computer. The corresponding manipulations are obtained. Experimental results show a good agreement between theory and experiment. We also generalize the scheme to transmit eight messages by introducing an additional two-state system. 相似文献
19.
Nilamoni Nath N. Suryaprakash 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2010,207(2):190-196
The increasing scientific and industrial interest towards metabonomics takes advantage from the high qualitative and quantitative information level of nuclear magnetic resonance (NMR) spectroscopy. However, several chemical and physical factors can affect the absolute and the relative position of an NMR signal and it is not always possible or desirable to eliminate these effects a priori. To remove misalignment of NMR signals a posteriori, several algorithms have been proposed in the literature. The icoshift program presented here is an open source and highly efficient program designed for solving signal alignment problems in metabonomic NMR data analysis. The icoshift algorithm is based on correlation shifting of spectral intervals and employs an FFT engine that aligns all spectra simultaneously. The algorithm is demonstrated to be faster than similar methods found in the literature making full-resolution alignment of large datasets feasible and thus avoiding down-sampling steps such as binning. The algorithm uses missing values as a filling alternative in order to avoid spectral artifacts at the segment boundaries. The algorithm is made open source and the Matlab code including documentation can be downloaded from www.models.life.ku.dk. 相似文献
20.
P. Tamain Ph. Ghendrih E. Tsitrone V. Grandgirard X. Garbet Y. Sarazin E. Serre G. Ciraolo G. Chiavassa 《Journal of computational physics》2010,229(2):361-378
We present a new code aiming at giving a global and coherent approach for transport and turbulence issues in the edge plasma of Tokamaks. The TOKAM-3D code solves 3D fluid drift equations in full-torus geometry including both closed field lines and SOL physics. No scale separation is assumed so that interactions between large scale flows and turbulence are coherently treated. Moreover, the code can be run in transport regimes ranging from purely anomalous diffusion to fully established turbulence. Specific numerical schemes have been developed which can solve the model equations whether the presence of a limiter in the plasma is taken into account or not. Example cases giving an overview of the field of application of the code as well as verification results are also presented. 相似文献