检索结果-南通市图书馆

Noise cancellation of a multi-reference full-wave magnetic resonance sounding signal based on a modified sigmoid variable step size least mean square algorithm

引用

Journal of Central South University 2017年第4期24卷 900-911页

作者：田宝凤周媛媛朱慧蒋川东易晓峰 Key Laboratory of Geo-Exploration Instrumentation Ministry of Education (Jilin University)Changchun 130026 China College of Instrumentation and Electrical Engineering Jilin University Changchun 130026 China

Nano-volt magnetic resonance sounding(MRS) signals are sufficiently weak so that during the actual measurement, they are affected by environmental electromagnetic noise, leading to inaccuracy of the extracted characteristic parameters and hindering effective inverse interpretation. Considering the complexity and non-homogeneous spatial distribution of environmental noise and based on the theory of adaptive noise cancellation, a model system for noise cancellation using multi-reference coils was constructed to receive MRS signals. The feasibility of this system with theoretical calculation and experiments was analyzed and a modified sigmoid variable step size least mean square(SVSLMS) algorithm for noise cancellation was presented. The simulation results show that, the multi-reference coil method performs better than the single one on both signal-to-noise ratio(SNR) improvement and signal waveform optimization after filtering, under the condition of different noise correlations in the reference coils and primary detecting coils and different SNRs. In particular, when the noise correlation is poor and the SNRmulti-reference coils. And the average fitting errors for initial amplitude and relaxation time are within 5%. Compared with the normalized least mean square(NLMS) algorithm and multichannel Wiener filter and processing field test data, the effectiveness of the proposed method is verified.

关键词： magnetic resonance sounding signal multi-reference coils adaptive noise cancellation sigmoid variable step size least mean square (SVSLMS)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A modified multi-reference second order perturbation theory

引用

中国科学：化学英文版 2010年第4期53卷 933-939页

作者： LI AnYang1, HAN HuiXian2, SUO BingBing3, WANG YuBin3 & WEN ZhenYi3 1Institute of Computational Chemistry, Chongqing University of Post and Telecommunications, Chongqing 400065, China 2Department of Physics, Northwest University, Xi’ an 710069, China 3Institute of Modern Physics, Northwest University, Xi’ an 710069, China Institute of Computational Chemistry Chongqing University of Post and Telecommunications Chongqing China Department of Physics Northwest University Xi’ an China Institute of Modern Physics Northwest University Xi’ an China

A new scheme with extended model space is proposed to improve the calculation of multi-reference second order perturbation theory (MRPT2). The new scheme preserves the concise code structure of the original program, and avoids intruder states in constructions of the potential energy surface, which is confirmed by a series of comparable calculations. The new MRPT2 program is an available tool for the research of molecular excited states and electronic spectrum.

关键词： perturbation theory multi-reference intruder state

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Configuration-based multi-reference second order perturbation theory

引用

Science China Chemistry 2000年第6期43卷 567-575页

作者：王育彬甘正汀苏克和文振翼 Institute of Modern Physics Northwest University Xi'an 710069 China Department of Chemical Engineering Northwestern Polytechnical University Xi'an 710072 China

Various configuration-based multi-reference second order perturbation approaches were investigated and a new scheme averting intruder states was suggested. The codes based on these schemes were tested by example calcu... 详细信息

关键词： perturbation theory multi-reference configuration interaction.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quantum-Mechanical Information Content of multiples Hartree-Fock Solutions. The multi-reference Hartree-Fock Configuration Interaction Method

引用

Journal of Modern Physics 2014年第7期5卷 543-548页

作者： Luiz Augusto Carvalho Malbouisson Antonio Moreira de Cerqueira Sobrinho Micael Dias de Andrade 1Departamento de Física do Estado Sólido do Instituto de Física da UFBA Salvador Brazil 2Departamento de Físico-Química do Instituto de Química da UFRJ Rio de Janeiro Brazil Departamento de Física do Estado Sólido do Instituto de Física da UFBA Salvador Brazil

The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction space. Although all Bω bases generate the same CI space, the corresponding configurations of each Bω base have distinct quantum-mechanical information contents. In previous works, we have introduced a multi-reference configuration interaction method, based on the multiple extremes of the Hartree-Fock problem. This method was applied to calculate the permanent electrical dipole and quadrupole moments of some small molecules using minimal and double, triple and polarized double-zeta bases. In all cases were possible, using a reduced number of configurations, to obtain dipole and quadrupole moments in close agreement with the experimental values and energies without compromising the energy of the state function. These results show the positive effect of the use of the multi-reference Hartree-Fock bases that allowed a better extraction of quantum mechanical information from the several Bω bases. But to extend these ideas for larger systems and atomic bases, it is necessary to develop criteria to build the multireference Hartree-Fock bases. In this project, we are beginning a study of the non-uniform distribution of quantum-mechanical information content of the Bω bases, searching identify the factors that allowed obtain the good results cited

关键词： multiple Hartree-Fock Solutions Quantum Mechanical Information Content multi-reference Hartre-Fock Configuration Interaction Method

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Low-lying electronic states of aluminum monoiodide

引用

Chinese Physics B 2019年第4期28卷 150-156页

作者：袁翔阴爽连艺颜培源徐海峰闫冰 Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University) Institute of Atomic and Molecular PhysicsJilin University

High-level ab initio calculations of aluminum monoiodide(AlI) molecule are performed by utilizing the multireference configuration interaction plus Davidson correction(MRCI+Q) method. The core-valence correlation(CV) and spin–orbit coupling(SOC) effect are considered. The adiabatic potential energy curves(PECs) of a total of 13 Λ–S states and 24 ? states are computed. The spectroscopic constants of bound states are determined, which are in accordance with the results of the available experimental and theoretical studies. The interactions between the Λ–S states are analyzed with the aid of the spin–orbit matrix elements. Finally, the transition properties including transition dipole moment(TDM),Frank–Condon factors(FCF) and radiative lifetime are obtained based on the computed PEC. Our study sheds light on the electronic structure and spectroscopy of low-lying electronic states of the AlI molecule.

关键词： AlI molecule potential energy curves(PECs) core-valence correlation spin–orbit coupling multi-reference configuration interaction(MRCI)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：