检索结果-内蒙古大学图书馆

Enhancement of photoluminescence efficiency in GeSe ultrathin slab by thermal treatment and annealing: experiment and first-principles molecular dynamics simulations

引用

Scientific reports 2018年第1期8卷 17671页

作者： Yuliang Mao Xin Mao Hongquan Zhao Nandi Zhang Xuan Shi Jianmei Yuan Hunan Key Laboratory for Micro-Nano Energy Materials and Devices School of Physics and Optoelectronic Xiangtan University Hunan 411105 China. ylmao@***. Hunan Key Laboratory for Micro-Nano Energy Materials and Devices School of Physics and Optoelectronic Xiangtan University Hunan 411105 China. Chongqing institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing 401120 China. hqzhao@***. Chongqing institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing 401120 China. Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Hunan 411105 China.

The effect of thermal treatment and annealing under different temperatures from 100 °C to 250 °C on the photoluminescence spectroscopy of the GeSe ultrathin slab is reported. After the thermal treatment and annealing under 200 °C, we found that the photoluminescence intensity of A exciton and B exciton in GeSe ultrathin slab is increased to twice as much as that in untreated case, while is increased by ~84% in the photoluminescence intensity of C exciton. Combined by our experimental work and theoretical simulations, our study confirms the significant role of thermal treatments and annealing in reducing surface roughness and removing the Se vacancy to form more compact and smoother regions in GeSe ultrathin slab. Our findings imply that the improved quality of GeSe surface after thermal treatments is an important factor for the photoluminescence enhancement.

关键词： Thermal Treatment First-principles Molecular Dynamics simulations Smoother Regions Reduced Surface Roughness GeSi Samples

来源：评论

学校读者我要写书评

暂无评论

Paired 2-Disjoint Path Covers of Burnt Pancake Graphs with Faulty Elements

SSRN

引用

SSRN 2024年

作者： Li, Pingshan Chen, Congzhen Liu, Xianglin Xiangtan University China School of Mathematics and Computational Science Xiangtan University Hunan Xiangtan411105 China Key Laboratory of Intelligent Computing & Information Processing of Education China Key Laboratory for Computation and Simulation in Science and Engineering China National Center for Applied Mathematics in Hunan China Guangxi Vocational University of Agriculture Guangxi Nanning530007 China

It is a key issue in parallel processing to find $k$-disjoint paths in the underlying graph of an interconnected network such that these disjoint paths pass through all vertices of the network, this is known as paired $k$-disjoint path cover problems or unpaired $k$-disjoint path cover problems. In 2024, Dvo\v{r}\'{a}k and Gu (Theoretical Computer science, $986 (2024) 114327$) showed that there exist two disjoint paths whose vertices partition the vertex of the burnt pancake graph even if it contains at most $n-4$ faulty elements (vertices or edges) and they proposed an open problem: is it possible to improve the upper bound $n-4$ to $n-3$? In this paper, we provide a positive answer to this problem. © 2024, The Authors. All rights reserved.

关键词： Hamiltonians

来源：评论

学校读者我要写书评

暂无评论

PRISTA-Net: Deep Iterative Shrinkage Thresholding Network for Coded Diffraction Patterns Phase Retrieval

arXiv

引用

arXiv 2023年

作者： Liu, Aoxu Fan, Xiaohong Yang, Yin Zhang, Jianping The School of Mathematics and Computational Science Xiangtan University Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan411105 China The School of Mathematics and Computational Science Xiangtan University the Key Laboratory of Intelligent Computing & Information Processing the Ministry of Education Xiangtan411105 China The School of Mathematics and Computational Science Xiangtan University the National Center for Applied Mathematics in Hunan Xiangtan411105 China

The problem of phase retrieval (PR) involves recovering an unknown image from limited amplitude measurement data and is a challenge nonlinear inverse problem in computational imaging and image processing. However, many of the PR methods are based on black-box network models that lack interpretability and plug-and-play (PnP) frameworks that are computationally complex and require careful parameter tuning. To address this, we have developed PRISTA-Net, a deep unfolding network (DUN) based on the first-order iterative shrinkage thresholding algorithm (ISTA). This network utilizes a learnable nonlinear transformation to address the proximal-point mapping sub-problem associated with the sparse priors, and an attention mechanism to focus on phase information containing image edges, textures, and structures. Additionally, the fast Fourier transform (FFT) is used to learn global features to enhance local information, and the designed logarithmic-based loss function leads to significant improvements when the noise level is low. All parameters in the proposed PRISTA-Net framework, including the nonlinear transformation, threshold parameters, and step size, are learned end-to-end instead of being manually set. This method combines the interpretability of traditional methods with the fast inference ability of deep learning and is able to handle noise at each iteration during the unfolding stage, thus improving recovery quality. Experiments on Coded Diffraction Patterns (CDPs) measurements demonstrate that our approach outperforms the existing state-of-the-art methods in terms of qualitative and quantitative evaluations. Our source codes are available at https://***/liuaxou/PRISTA-Net. Copyright © 2023, The Authors. All rights reserved.

关键词： Mapping

来源：评论

学校读者我要写书评

暂无评论

Uniform convergence of multigrid finite element method for time-dependent riesz tempered fractional problem

arXiv

引用

arXiv 2017年

作者： Chen, Minghua Bu, Weiping Qi, Wenya Wang, Yantao School of Mathematics and Statistics Gansu Key Laboratory of Applied Mathematics and Complex Systems Lanzhou University Lanzhou730000 China School of Mathematics and Computational Science Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan411105 China South University of Science and Technology of China Shenzhen518055 China

In this article a theoretical framework for the Galerkin finite element approximation to the time-dependent Riesz tempered fractional problem is provided without the fractional regularity assumption. Because the time-dependent problems should become easier to solve as the time step τ → 0, which correspond to the mass matrix dominant [R. E. Bank and T. Dupont, Math. Comp., 153 (1981), pp. 35-51]. Based on the introduced and analysis of the fractional τ-norm, the uniform convergence estimates of the V-cycle multigrid method with the time-dependent fractional problem is strictly proved, which means that the convergence rate of the V-cycle MGM is independent of the mesh size h and the time step τ. The numerical experiments are performed to verify the convergence with only O(NlogN) complexity by the fast Fourier transform method, where N is the number of the grid points. To the best of our knowledge, this is the first proof for the convergence rate of the V-cycle multigrid finite element method with τ → 0. Copyright © 2017, The Authors. All rights reserved.

关键词： Fast Fourier transforms

来源：评论

学校读者我要写书评

暂无评论

Adaptive-multilevel BDDC algorithm for three-dimensional plane wave Helmholtz systems

arXiv

引用

arXiv 2019年

作者： Peng, Jie Shu, Shi Wang, Junxian Zhong, Liuqiang School of Mathematical Sciences South China Normal University Guangzhou510631 China School of Mathematics and Computational Science Xiangtan University Xiangtan411105 China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan411105 China

In this paper we are concerned with the weighted plane wave least-squares (PWLS) method for three-dimensional Helmholtz equations, and develop the multi-level adaptive BDDC algorithms for solving the resulting discrete system. In order to form the adaptive coarse components, the local generalized eigenvalue problems for each common face and each common edge are carefully designed. The condition number of the two-level adaptive BDDC preconditioned system is proved to be bounded above by a user-defined tolerance and a constant that is only dependent on the maximum number of faces and edges per subdomain and the number of subdomains sharing a common edge. The effectiveness of these algorithms is illustrated on benchmark problem. The numerical results show the robustness of our two-level adaptive BDDC algorithms with respect to the wave number, the number of subdomains and the mesh size, and appear that our multi-level adaptive BDDC algorithm can reduce the number of dofs at the coarse problem and can be used to solving large wave number problems efficiently. Copyright © 2019, The Authors. All rights reserved.

关键词： Elastic waves

来源：评论

学校读者我要写书评

暂无评论

Synthesis of 4-aryl-1,4-dihydropyridine-porphyrin Compounds

Synthesis of 4-aryl-1,4-dihydropyridine-porphyrin Compounds

引用

中国化学会第二十七届学术年会

作者： Fei Yao Hui Wang Rong-Jin Zeng Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education School of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan411201

来源：评论

学校读者我要写书评

暂无评论

Design and Adaptive Finite Element simulation of Conformal Transformation Optics Devices with Isotropic Materials

SSRN

引用

SSRN 2022年

作者： Yang, Wei He, Bin Wang, Hao Department of Mathematics Lanzhou Jiaotong University Gansu Lanzhou730070 China School of Mathematics and Statistics Anhui Normal University Anhui Wuhu241000 China Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Hunan Xiangtan411105 China

Traditional transform optical devices are designed from anisotropic magnetic materials which are difficult to fabricate. In this paper, we design and simulate a conformal carpet invisible cloak and bending waveguide device with isotropic material. According to the existing conformal coordinate transformation, we deduce the perfect parameters required by the conformal device. And the finite element method and error analysis of the model equation and the basic process of adaptive algorithm are given. We first simulated a carpet cloak and bending waveguide device with perfect parameters;then we used the idea of parameter segmentation to design a carpet cloak that requires 35 isotropic materials and use the idea of layering to design the conformal bending waveguide device, and relevant numerical results are presented;finally, we designed the adaptive finite element algorithm to realize the numerical simulation of Maxwell's equations in isotropic material isotropic material. © 2022, The Authors. All rights reserved.

关键词： Error analysis

来源：评论

学校读者我要写书评

暂无评论

The Control Design of Space Flying Net Robot System Based on RBF Network

The Control Design of Space Flying Net Robot System Based on...

引用

Chinese Automation Congress (CAC)

作者： Xu Zhang Yuanhe Liu Yan’gang Liang Kebo Li Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions College of Aerospace Science and Engineering National University of Defense Technology Changsha China

ISBN: (纸本)9781665426480

Space Flying Net Robot System (SFNRS) is a new capture method of space debris. In this paper, the SFNRS dynamic equations are established by using the lumped mass method. The previous studies about controller design assumed that the mass of the maneuvering unit in SFNRS is known and a constant while it is unknown in fact. In addition, the upper boundary of tension in the space net is often assumed as a known constant, but it is difficult to get the value. In this paper, the radial basis function (RBF) network is used to design a controller in order to overcome the shortcomings above. Finally, the simulation is carried out to verify the effectiveness and the robustness of the proposed method.

关键词： Upper bound Control design Space debris simulation Radial basis function networks Aerospace electronics Robustness

来源：评论

学校读者我要写书评

暂无评论

Financing strategy of SMEs based on the shortage of environmental protection funds

引用

Procedia Computer science 2022年 199卷 1521-1528页

作者： Wang Haiyang Zhuang Xiaohui College of Automation and Electronic Engineering Qingdao University of Science & Technology Qingdao 260061 China School of Management Shandong Key Laboratory of Social Supernetwork Computation and Decision Simulation Shandong University Jinan Shandong 250100 China

With the development of society, environmental protection issues have received increasing attention. The increase in environmental protection requirements has greatly affected small and medium-sized enterprises（SMEs）. Due to the poor credit status and imperfect systems of SMEs, financing is difficult and expensive, which makes environmental protection funds insufficient, leading to outstanding environmental protection problems. In the supply chain, in order to maintain the stability of the supply chain, the core enterprises will help SMEs to alleviate the funding difficulties. This article starts from the supply chain financing of SMEs, explores the specific ways that core enterprises can help SMEs in supply chain financing, and analyses the feasibility of financing methods. Through analysis and demonstration, it is found that core enterprises can help SMEs with supply chain financing through prepayments, help small and medium-sized suppliers solve the problem of insufficient environmental protection funds, and core enterprises can obtain benefits from it.

关键词： Supply Chain Finance Small medium-sized enterprises (SMEs) Prepayments

来源：评论

学校读者我要写书评

暂无评论

Multifractal analysis of complex networks

引用

Chinese Physics B 2012年第8期21卷 080504-1-080504-1-080504-11页

作者： Wang, Dan-Ling Yu, Zu-Guo Anh, V. School of Mathematical Sciences Queensland University of Technology GPO Box 2434 Brisbane QC 4001 Australia School of Mathematics and Physics University of Science and Technology Beijing Beijing 10083 China Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Xiangtan 411105 China

Complex networks have recently attracted much attention in diverse areas of science and technology. Many networks such as the WWW and biological networks are known to display spatial heterogeneity which can be characterized by their fractal dimensions. Multifractal analysis is a useful way to systematically describe the spatial heterogeneity of both theoretical and experimental fractal patterns. In this paper, we introduce a new box-covering algorithm for multifractal analysis of complex networks. This algorithm is used to calculate the generalized fractal dimensions Dq of some theoretical networks, namely scale-free networks, small world networks, and random networks, and one kind of real network, namely protein - protein interaction networks of different species. Our numerical results indicate the existence of multifractality in scale-free networks and protein - protein interaction networks, while the multifractal behavior is not clear-cut for small world networks and random networks. The possible variation of Dq due to changes in the parameters of the theoretical network models is also discussed. © 2012 Chinese Physical Society and IOP Publishing Ltd.

关键词： Small-world networks

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：