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Atomistic Simulations of the Mechanical Deformation of Irradiation-amorphized Silicon Carbide

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Chinese Journal of Mechanical Engineering 2010年第6期23卷 671-676页

作者： XUE Kun NIU lisha SHI Huiji Department of Engineering Mechanics Tsinghua University Beijing 100084 China

Irradiation-induced atomic-scale defects and lattice disorder in Silicon Carbide （SIC） can significantly affect the material＇s mechanical properties. Currently there lacks a unified physical model capable of describing the law in which the properties of SiC scale with the accumulation of defects, especially in terms of the underlying physical mechanism. To develop fundamental models that are capable of describing the various physical properties of SiC as a function of microstructural change, molecular dynamics simulations of uniaxial tension were performed on a series of irradiation-amorphized SiC （a-SiC） samples with a range of imposed chemical disorder, which is defined as the ratio between the number of homonuclear bonds and heteronuclear bonds （x = Nc-c / Nsi-c）. With increasing chemical disorder, significant alternation of mechanical response of a-SiC has been detected in terms of increasingly pronounced plastic flow. Meanwhile relevant mechanical properties, including Young＇s modulus, strength, yield stress and strain, as well as failure strain scale monotonically with chemical disorder while in distinct manners. Specifically slight chemical disorder （x = 0.045） could induce substantial reduction of Young＇s modulus up to -2%, whereas strength basically linearly varies with chemical disorder until x≈0.5 upon which the variations in mechanical properties tend to saturate. Further examination of the evolution of atomic structure of a-SiC reveals a crossover of deformation mechanisms from homogeneous elastic deformation to localized plastic flow, which accounts for the strong chemical disorder dependence of the mechanical properties as well as mechanical responses of amorphous SiC. This crossover is also manifested in switching of fracture mode from brittle failure dominated by lattice instability in the ligaments between topological disordered clusters to nanoductile failure preceded by percolation of nanocavities. Employing chemical disorder to measure the defec

关键词： silicon carbide irradiation-amorphization molecular dynamics modeling tensile test chemical disorder

Expression Recognition Method Based on Convolutional Neural Network and Capsule Neural Network

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Computers, Materials & Continua 2024年第4期79卷 1659-1677页

作者： Zhanfeng Wang lisha Yao School of Computer Science and Artificial Intelligence Chaohu UniversityHefei238000China School of Big Data and Artificial Intelligence Anhui Xinhua UniversityHefei230088China

Convolutional neural networks struggle to accurately handle changes in angles and twists in the direction of images,which affects their ability to recognize patterns based on internal feature levels. In contrast, CapsNet overcomesthese limitations by vectorizing information through increased directionality and magnitude, ensuring that spatialinformation is not overlooked. Therefore, this study proposes a novel expression recognition technique calledCAPSULE-VGG, which combines the strengths of CapsNet and convolutional neural networks. By refining andintegrating features extracted by a convolutional neural network before introducing theminto CapsNet, ourmodelenhances facial recognition capabilities. Compared to traditional neural network models, our approach offersfaster training pace, improved convergence speed, and higher accuracy rates approaching stability. Experimentalresults demonstrate that our method achieves recognition rates of 74.14% for the FER2013 expression dataset and99.85% for the CK+ expression dataset. By contrasting these findings with those obtained using conventionalexpression recognition techniques and incorporating CapsNet’s advantages, we effectively address issues associatedwith convolutional neural networks while increasing expression identification accuracy.

关键词： Expression recognition capsule neural network convolutional neural network

Epitranscriptome engineering in crop improvement

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Molecular Plant 2021年第9期14卷 1418-1420页

作者： lisha Shen Hao Yu Temasek Life Sciences Laboratory National University of Singapore1 Research LinkSingapore 117604Singapore Department of Biological Sciences National University of Singapore14 Science Drive 4Singapore 117543Singapore

Biochemical modifications of RNAs,collectively designated as the epitranscriptome,have emerged as fundamental mechanisms derlying gene *** studies have shown that N6-methyladenosine(m6A)and 5-methycytosine(m5C)modifications govern multifaceted developmental processes and environmental resporises in *** potential of engineering the epitranscrip-tome in crop improvement was nicely demonstrated in a recent study(Yu et al.,2021),where the authors took advantage of epitranscriptome engi neering to vigorously in crease crop yield.

关键词： transcriptome al collective

Impact of monoculture of poplar on rhizosphere microbial communities over time

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Pedosphere 2020年第4期30卷 487-495页

作者： Qian LU Jinchi ZHANG lisha CHEN Department of Water and Soil Conservation College of ForestryNanjing Forestry UniversityNanjing 210037China

To date, research on the adverse effects of continuous cropping has focused on field crops;forest plantations, despite their very significant economic and ecological value, have received less attention. The evolution of microbial community in the rhizosphere of forest plantations, in particular, has rarely been examined. In this study, changes in the size, composition, and structure of bacterial and fungal communities in the rhizosphere of different generations of poplar (Populus deltoides) plantations were studied using real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis and compared with the composition of the microbial community in a bare land (control) adjacent to the plantation sites through sequencing analysis and by constructing phylogenetic trees. The numbers of bacteria and fungi increased significantly with successive poplar generations, although the increases in the two groups were not parallel. When compared with the control, the bacterial community increased greatly in the second generation, and the most significant increase occurred in the third generation. In contrast, the most significant increase in the fungal community occurred in the first generation, and the increase in the third generation was insignificant. In terms of community composition, the first generation showed little change in either community;however, the second generation showed remarkable changes in the bacterial community, and the third in the fungal community. The numbers of Gammaproteobacteria,Alphaproteobacteria, and Actinobacteria increased by 10.92%, 7.38%, and 5.46%, respectively, whereas those of Acidobacteria decreased by 18.38%in the second generation. These changes in the number and composition of microbial communities in the rhizosphere could be one of the reasons for the decline in yield and quality associated with long-term monoculture.

关键词： bacterial community continuous cropping denaturing gradient gel electrophoresis forest plantations fungal community polymerase chain reaction Populus deltoides

Reconstructing the Nonlinear Dynamical Systems by Evolutionary Computation Techniques

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Wuhan University Journal of Natural Sciences 2006年第3期11卷 520-524页

作者： LIU Minzhong KANG lisha School of Computer Wuhan University Wuhan 430072 Hubei China State Key Laboratory of Software Engineering Wuhan University Wuhan 430072 Hubei China

We introduce a new dynamical evolutionary algorithm（DEA） based on the theory of statistical mechanics and investigate the reconstruction problem for the nonlinear dynamical systems using observation data. The convergence of the algorithm is discussed. We make the numerical experiments and test our model using the two famous chaotic systems （mainly the Lorenz and Chen systems）. The results show the relatively accurate reconstruction of these chaotic systems based on observational data can be obtained. Therefore we may conclude that there are broad prospects using our method to model the nonlinear dynamical systems.

关键词： dynamical evolutionary algorithm nonlinear dynamical systems reconstruction

DP-UserPro:differentially private user profile construction and publication

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Frontiers of Computer Science 2021年第5期15卷 197-206页

作者： Zheng HUO Ping HE lisha HU Huanyu ZHAO Information Technology School Hebei University of Economics and BusinessShijiazhuang 050061China The Institute of Applied Mathematics Hebei Academy of SciencesShijiazhuang 050051China Hebei Authentication Technology Engineering Research Center Shijiazhuang 050051China

User profiles are widely used in the age of big ***,generating and releasing user profiles may cause serious privacy leakage,since a large number of personal data are collected and *** this paper,we propose a differentially private user profile construction method DP-UserPro,which is composed of DP-CLIQUE and privately top-κtags ***-CLIQUE is a differentially private high dimensional data cluster algorithm based on *** multidimensional tag space is divided into cells,Laplace noises are added into the count value of each *** on the breadth-first-search,the largest connected dense cells are clustered into a *** a privately top-κtags selection approach is proposed based on the score function of each tag,to select the most importantκtags which can represent the characteristics of the *** and utility of DP-UserPro are theoretically analyzed and experimentally evaluated in the *** experiments are carried out with Tag Suppression algorithm on two real datasets,to measure the False Negative Rate(FNR)and *** results show that DP-UserPro outperforms Tag Suppression by 62.5%in the best case and 14.25%in the worst case on FNR,and DP-UserPro is about 21.1%better on precision than that of Tag Suppression,in average.

关键词： user profile DP-CLIQUE clustering differential privacy recommender system

Effect of the nano/microscale structure of biomaterial scaffolds on bone regeneration

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International Journal of Oral Science 2020年第1期12卷 10-24页

作者： lisha Zhu Dan Luo Yan Liu Laboratory of Biomimetic Nanomaterials Department of OrthodonticsPeking University School and Hospital of StomatologyNational Engineering Laboratory for Digital and Material Technology of StomatologyBeijing Key Laboratory of Digital StomatologyBeijingChina State Key Laboratory of Heavy Oil Processing College of New Energy and MaterialsBeijing Key Laboratory of Biogas Upgrading UtilizationChina University of Petroleum(Beijing)BeijingChina

Natural bone is a mineralized biological material, which serves a supportive and protective framework for the body, stores minerals for metabolism, and produces blood cells nourishing the body. Normally, bone has an innate capacity to heal from ***, massive bone defects due to traumatic injury, tumor resection, or congenital diseases pose a great challenge to reconstructive surgery. Scaffold-based tissue engineering(TE) is a promising strategy for bone regenerative medicine, because biomaterial scaffolds show advanced mechanical properties and a good degradation profile, as well as the feasibility of controlled release of growth and differentiation factors or immobilizing them on the material surface. Additionally, the defined structure of biomaterial scaffolds, as a kind of mechanical cue, can influence cell behaviors, modulate local microenvironment and control key features at the molecular and cellular levels. Recently, nano/micro-assisted regenerative medicine becomes a promising application of TE for the reconstruction of bone defects. For this reason, it is necessary for us to have in-depth knowledge of the development of novel nano/micro-based biomaterial scaffolds. Thus, we herein review the hierarchical structure of bone, and the potential application of nano/micro technologies to guide the design of novel biomaterial structures for bone repair and regeneration.

关键词： structure stores protective

Simulating the development of resilient human settlement in Changsha

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Journal of Geographical Sciences 2022年第8期32卷 1513-1529页

作者： TANG lisha LONG Hualou School of Business Hunan First Normal UniversityChangsha 410205China School of Public Administration Guangxi UniversityNanning 530004China Institute of Geographic Sciences and Natural Resources Research CASBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Using the system dynamics simulation software Vensim PLE, we built a model to simulate the development of resilient human settlement in Changsha. This model includes five subsystems: living, economy, society, ecology and engineering. The model simulates various scenarios, based on different parameter settings to predict the trend of human settlement from 2019–2040 in Changsha. It puts forward four development programs under different simulation scenarios. The results show that the current system of human settling lacks self-regulation and feedback, where simple increases in the economy and urbanization cannot drive the internal system to progress positively. In contrast, the resilient human settlement program is more reasonable and scientific, up to the year 2040, the production, living and ecological environment of residents will be markedly improved in terms of per capita disposable income, per capita floor space and medical insurance coverage;these will increase by 98.9%, 39.7%, and 170.7%, respectively. This system of developing resilient human settlement provides feedback according to the internal relation loops and thus drives itself to adjust and recover, achieving harmonious and sustainable development. In the forthcoming development, we should take the initiative to optimize economic development and upgrade industrial structures, establish emergency plans and response mechanisms to enhance human quality of life.

关键词： human settlement resilience system dynamics simulation sustainable development

Discussion of Online Teaching Strategies for Teaching Elementary Chinese Characters to Foreigners Based on Error Analyses

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Contemporary Social Sciences 2023年第2期8卷 96-116页

作者： Guo lisha School of Overseas Education Sichuan UniversityChengduSichuan610066China

The expanding role of the Chinese language in international communications has become increasingly prominent as China’s comprehensive national power continues to grow,leading to a significant rise in the number of Chinese language *** online teaching is not limited by time and space,its application is *** beginners in the Chinese language,the Chinese characters are both a priority and a ***“Chinese Character Classification,”also known as the“Six Writings,”is the earliest systematic theory of Chinese character structures,and teaching Chinese characters in categories based on the“Chinese Character Classification”is a method that fits the cognition of *** order to teach Chinese characters in a targeted approach,based on the collection and analysis of the common errors of Chinese characters among beginners,(1)this paper proposes that(a)the intuitive method can be applied to teach pictographic characters,indicative characters,and associative compound characters in online teaching;(b)the inductive-deductive method of“basic characters to new characters”can be applied for the teaching of pictophonetic characters and associative compound characters;(c)the learning of character patterns should be approached in a whole-part-whole process,while importance should be attached to the suggestion of the frequency effect with a view to facilitating the online learning of Chinese characters for *** aim of this paper is to provide some practical implications for the online teaching of Chinese characters to foreigners.

关键词： error online teaching Chinese as a foreign language teaching elementary Chinese characters Chinese Character Classification