检索结果-南通市图书馆

Transient responses of double-curved sandwich two-layer shells resting on Kerr's foundations with laminated three-phase polymer/GNP/fiber surface and auxetic honeycomb core subjected to the blast load

引用

Defence Technology（防务技术） 2024年第5期35卷 222-247页

作者： nguyen Thi Hai Van Thi hong nguyen Researcher&Lecturer Faculty of Industrial EducationThe University of Danang-University of Technology and Education48 Cao ThangDanang550000Viet Nam Researcher&Lecturer Faculty of Mechanical EngineeringThuyloi University175 Tay SonDong DaHanoi100000Viet Nam

This work uses refined first-order shear theory to analyze the free vibration and transient responses of double-curved sandwich two-layer shells made of auxetic honeycomb core and laminated three-phase polymer/GNP/fiber surface subjected to the blast *** of the two layers that make up the double-curved shell structure is made up of an auxetic honeycomb core and two laminated sheets of three-phase polymer/GNP/*** exterior is supported by a Kerr elastic foundation with three *** key innovation of the proposed theory is that the transverse shear stresses are zero at two free surfaces of each *** contrast to previous first-order shear deformation theories,no shear correction factor is ***'s exact solution was used to treat the double-curved shell problem with a single title boundary,while the finite element technique and an eight-node quadrilateral were used to address the other boundary *** ensure the accuracy of these results,a thorough comparison technique is employed in conjunction with credible *** problem model's edge cases allow for this kind of *** study's findings may be used in the post-construction evaluation of military and civil works structures for their ability to sustain explosive *** addition,this is also an important basis for the calculation and design of shell structures made of smart materials when subjected to shock waves or explosive loads.

关键词： Blast load Two-layer shell Polymer/GNP/Fiber surface Auxetic honeycomb Shear connectors

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

Weak type(1, 1) of the Riesz transform on some direct product manifolds with exponential volume growth

引用

Science China Mathematics 2024年第7期67卷 1599-1622页

作者： hong-quan Li Jie-Xiang Zhu School of Mathematical Sciences Fudan UniversityShanghai200433China Center for Applied Mathematics Tianjin UniversityTianjin300072China

In this paper, we are concerned with the Riesz transform on the direct product manifold H^(n)× M,where H^(n) is the n-dimensional real hyperbolic space, and M is a connected complete non-compact Riemannian manifold satisfying the volume doubling property and generalized Gaussian or sub-Gaussian upper estimates for the heat kernel. We establish its weak type(1, 1) property. In addition, we obtain the weak type(1, 1) of the heat maximal operator in the same setting. Our arguments also work for a large class of direct product manifolds with exponential volume growth. Particularly, we provide a simpler proof of weak type(1, 1) boundedness of some operators considered in the work of Li et al.(2016).

关键词： Riesz transform heat kernel direct product real hyperbolic space

来源：

维普期刊数据库

同方期刊数据库

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

Transient response of doubly-curved bio-inspired composite shells resting on viscoelastic foundation subject to blast load using improved first-order shear theory and isogeometric approach

引用

Defence Technology（防务技术） 2024年第8期38卷 171-193页

作者： Thuy Tran Thi Thu Tu nguyen Anh Hue nguyen Thi hong nguyen Thi School of Mechanical and Automotive Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Technical Fundamental University of Transport TechnologyHanoiViet Nam Faculty of Mechanical Engineering Thuyloi University175 Tay SonDong DaHanoiViet Nam

Investigating natural-inspired applications is a perennially appealing subject for scientists. The current increase in the speed of natural-origin structure growth may be linked to their superior mechanical properties and environmental resilience. Biological composite structures with helicoidal schemes and designs have remarkable capacities to absorb impact energy and withstand damage. However, there is a dearth of extensive study on the influence of fiber redirection and reorientation inside the matrix of a helicoid structure on its mechanical performance and reactivity. The present study aimed to explore the static and transient responses of a bio-inspired helicoid laminated composite(B-iHLC) shell under the influence of an explosive load using an isomorphic method. The structural integrity of the shell is maintained by a viscoelastic basis known as the Pasternak foundation, which encompasses two coefficients of stiffness and one coefficient of damping. The equilibrium equations governing shell dynamics are obtained by using Hamilton's principle and including the modified first-order shear theory,therefore obviating the need to employ a shear correction factor. The paper's model and approach are validated by doing numerical comparisons with respected publications. The findings of this study may be used in the construction of military and civilian infrastructure in situations when the structure is subjected to severe stresses that might potentially result in catastrophic collapse. The findings of this paper serve as the foundation for several other issues, including geometric optimization and the dynamic response of similar mechanical structures.

关键词： Blast load Modified first-order shear theory Biological composite structures

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

Design and modification of metal sulfide-based catalysts for lithiumsulfur batteries

引用

Particuology 2024年第3期86卷 86-100页

作者： Yufei Zhao Chuannan Geng Li Wang Haotian Yang Wei Lv quan-hong Yang Nanoyang Group State Key Laboratory of Chemical EngineeringSchool of Chemical Engineering and TechnologyNational Industry-Education Integration Platform of Energy Storageand Collaborative Innovation Center of Chemical Science and Engineering(Tianjin)Tianjin UniversityTianjin300072China Shenzhen Geim Graphene Center Engineering Laboratory for Functionalized Carbon MaterialsTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China Haihe Laboratory of Sustainable Chemical Transformations Tianjin300192China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou350207China

Metal sulfide(MS)have good conductivity,strong adsorption ability,and excellent catalytic activity for the conversion of sulfur species,and thus,show great promise as the catalysts in LieS ***,the relationship between their properties and electrochemical performance is still ***,further in-depth discussions are required to improve their design in Li-S *** review systematically summarizes the basic structural and electrochemical properties of MSs and highlights the advantages that guarantee them as high-performance catalysts in Li-S ***,various modification strategies for MSs to enhance the catalytic activity,efficiency,and stability are also *** last,future opportunities for MS catalysts in Li-S batteries are proposed.

关键词： Lithium-sulfur battery Metal sulfide Catalysis

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

Aberrant LETM1 elevation dysregulates mitochondrial functions and energy metabolism and promotes lung metastasis in osteosarcoma

引用

Genes & Diseases 2024年第3期11卷 368-384页

作者： Yulu Shi quan Kang hong Zhou Xiaohan Yue Yang Bi Qing Luo Stem Cell Biology and Therapy Laboratory The Children's Hospital of Chongqing Medical UniversityNational Clinical Research Center for Child Health and DisordersMinistry of Education Key Laboratory of Child Development and DisordersChongqing Key Laboratory of PediatricsChongqing 400014China Department of Pediatric Surgery The Children's Hospital of Chongqing Medical UniversityChongqing 400014China

Osteosarcoma is a differentiation-deficient disease,and despite the unique advan-tages and great potential of differentiation therapy,there are only a few known differentia-tion inducers,and little research has been done on their *** differentiation is associated with an increase in mitochondrial content and *** metabolism of some tu-mor cells is characterized by impaired oxidative phosphorylation,as well as up-regulation of aerobic glycolysis and pentose phosphate ***-containing zipper and EF-hand transmembrane protein 1(LETM1)is involved in the maintenance of mitochondrial morphology and is closely associated with tumorigenesis and progression,as well as cancer cell *** found that MG63 and 143B osteosarcoma cells overexpress LETM1 and exhibit abnormalities in mitochondrial structure and *** of LETM1 partially restored the mitochon-drial structure and function,inhibited the pentose phosphate pathway,promoted oxidative phosphorylation,and led to osteogenic *** also inhibited spheroid cell forma-tion,proliferation,migration,and invasion in an in vitro *** LETM1 was knocked down in vivo,there was reduced tumor formation and lung *** data suggest that mitochondria are aberrant in LETM1-overexpressing osteosarcoma cells,and knockdown of LETM1 partially restores the mitochondrial structure and function,inhibits the pentose phosphate pathway,promotes oxidative phosphorylation,and increases osteogenic differentiation,thereby reducing malignant biological behavior of the cells.

关键词： Cancer metabolism Differentiation LETM1 Osteosarcoma Stemness

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

Programmable repulsive potential for tight-binding from Chen-Möbius inversion theorem

引用

Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 71-83页

作者： Jian-Gao Li Jin-Kun Tang hong-quan Song Gotthard Seifert Dong-Bo Zhang College of Nuclear Science and Technology Beijing Normal UniversityBeijing 100875China Department of Physics Beijing Normal UniversityBeijing 100875China College of Physics and Telecommunication Engineering Zhoukou Normal UniversityZhoukou 466001China Theoretische Chemie Technische Universität DresdenDresden D-01062Germany

An accurate total energy calculation is essential in materials *** date,many tight-binding(TB)approaches based on parameterized hopping can produce electronic structures comparable to those obtained using first-principles ***,TB approaches still have limited applicability for determining material properties derived from the total *** is,the predictive power of the TB total energy is impaired by an inaccurate evaluation of the repulsive *** complexity associated with the parametrization of TB repulsive potentials is the weak link in this *** this study,we propose a new method for obtaining the pairwise TB repulsive potential for crystalline materials by employing the Chen-Möbius inversion *** show that the TB-based phonon dispersions,calculated using the resulting repulsive potential,compare well with those obtained by first-principles calculations for various systems,including covalent and ionic bulk materials and twodimensional *** present approach only requires the first-principles total energy and TB electronic band energy as input and does not involve any *** striking feature enables us to generate repulsive potentials programmatically.

关键词： tight binding first-principles calculation total energy repulsive potential phonon dispersion

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

Enhancing personalized exercise recommendation with student and exercise portraits

引用

Journal of Electronic Science and Technology 2024年第2期22卷 91-109页

作者： Wei-Wei Gao Hui-Fang Ma Yan Zhao Jing Wang quan-hong Tian College of Computer Science and Engineering Northwest Normal UniversityLanzhou730070China Computer Center of Gansu Province Lanzhou730070China

The exercise recommendation system is emerging as a promising application in online learning scenarios,providing personalized recommendations to assist students with explicit learning *** solutions generally follow a collaborative filtering paradigm,while the implicit connections between students(exercises)have been largely *** this study,we aim to propose an exercise recommendation paradigm that can reveal the latent connections between student-student(exercise-exercise).Specifically,a new framework was proposed,namely personalized exercise recommendation with student and exercise portraits(PERP).It consists of three sequential and interdependent modules:Collaborative student exercise graph(CSEG)construction,joint random walk,and recommendation list ***,CSEG is created as a unified heterogeneous graph with students’response behaviors and student(exercise)***,a joint random walk to take full advantage of the spectral properties of nearly uncoupled Markov chains is performed on CSEG,which allows for full exploration of both similar exercises that students have finished and connections between students(exercises)with similar ***,we propose to optimize the recommendation list to obtain different exercise *** analyses of two public datasets,the results demonstrated that PERP can satisfy novelty,accuracy,and diversity.

关键词： Educational data mining Exercise recommend Joint random walk Nearly uncoupled Markov chains Optimization Personalized learning

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

Harmonic State Space Based Impedance Modeling and Virtual Impedance Based Stability Enhancement Control for LCC-HVDC Systems

引用

Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 287-298页

作者： Yifeng Liu Xiaoping Zhou quan Chen Hanhang Yin Lerong hong Hao Tian Ying Chen Siyuan Li the College of Electrical and Information Engineering Hunan UniversityChangsha 410082China the Zhejiang Magtron Intelligent Technology Limited Cooperation Jiaxing 314000China the State Grid Qianjiang Electric Power Company Qianjiang 433100China

Line commutated converter based high-voltage direct-current(LCC-HVDC)transmissions are prone to harmonic oscillation under weak *** modeling is an effective method for assessing interaction ***,this paper proposes an improved calculation method for the DC voltage and AC currents of commutation stations to address the complex linearization of the commutation process and constructs an overall harmonic state-space(HSS)model of an *** on the HSS model,the closed-loop AC impedances on the LCC-HVDC sending and receiving ends are then derived and *** impedance characteristics of the LCC-HVDC are then analyzed to provide a physical explanation for the harmonic oscillation of the *** effects of the grid strength and control parameters on system stability are also *** improve the impedance characteristics and operating stability of the LCC-HVDC system,a virtual impedance based stability enhancement control is proposed,and a parameter design method is considered to ensure satisfactory phase margins at both the sending and receiving ***,simulation results are presented to verify the validity of the impedance model and virtual impedance based stability enhancement control.

关键词： Line commutated converter based high-voltage direct-current(LCC-HVDC)transmission harmonic state space stability analysis harmonic oscillation virtual impedance

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

Numerical and experimental study of the effects of wind turbine operation on sand-dust transport characteristics

引用

Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 97-113页

作者： Gaosheng Ma hong Han Ye Li Deshun Li Yan Wang Ning Fu quan Zheng Rennian Li School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou 730050China Gansu Provincial Technology Center for Wind Turbines Lanzhou 730050China Key Laboratory of Fluid Machinery and Systems Lanzhou 730050China Multiple Function Towing Tank Laboratory State Key Laboratory of Ocean EngineeringSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Given factors such as reduced land availability for onshore wind farms,wind resource enrichment levels,and costs,there is a growing trend of establishing wind farms in deserts,the Gobi,and other arid ***,the relationship between sanddust weather environments and wind turbine operations has garnered significant *** investigate the impact of wind turbine wakes on sand-dust transportation,this study employs large eddy simulation to model flow fields,coupled with an actuator line model for simulating rotating blades and a multiphase particle in cell model for simulating sand *** research focuses on a horizontal axis wind turbine model and examines the motion and spatiotemporal distribution characteristics of four typical sizes of sand particles in the turbine *** findings reveal that sand particles of varying sizes exhibit a spiral settling pattern after traversing the rotating plane of wind turbine blades,influenced by blade shedding vortex and *** particles tend to cluster in the peripheries of the vortex cores of low vorticity in the wind turbine *** rotation of wind turbines generates a wake vortex structure that causes a significant clustering of sand particles at the tip *** the wake distance increases,the particles that cluster at the turbine's tip gradually spread outward to approximately twice the rotor diameter and then begin to mix with the incoming flow *** turbines have a noticeable impact on sand-dust transportation,hindering their movement to a significant *** average sand-blocking rate exhibits a trend of initially increasing and then decreasing as the wake distance *** its peak,the sand-blocking rate reaches an impressive 67.55%.The presence of wind turbines induces the advanced settling of sand particles,resulting in a“triangular”distribution of the deposition within the ground projection area of the wake.

关键词： wind turbine particle transportation actuator line model dry deposition particle clustering

来源：

维普期刊数据库

同方期刊数据库

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

Correlations of transcranial sonography of substantia nigra characteristics with MRI iron deposition on substantia nigra in patients with Parkinson disease

引用

中国医学影像技术 2024年第8期40卷 1160-1163页

作者： ZOU quan CHEN Fei MENG Wenyu ZHENG hong Department of Ultrasound Medicine the First Hospital of Lanzhou UniversityLanzhou 730000China

Objective To explore the correlations of transcranial sonography of substantia nigra(SN-TCS)characteristics with MRI iron deposition on substantia nigra in patients with Parkinson disease(PD).Methods Data of SN-TCS and craniocerebral MRI in 120 PD patients were retrospectively *** patients were divided into iron deposition positive group(positive group,n=46)and iron deposition negative group(negative group,n=74)according to quantitative susceptibility mapping(QSM)*** parameters of SN-TCS and MRI were compared between groups(both P0.05).Strong echo area of substantia nigra and S/M based on SN-TCS were both low-medium positively correlated with substantia nigra QSM value showed on MRI(r=0.497,0.529,both P<0.001).Conclusion SN-TCS characteristics of PD patients were correlated with MRI iron deposition on substantia nigra,among which strong echo area and S/M were valuable for evaluating iron deposition on substantia nigra.

关键词： Parkinson disease substantia nigra iron ultrasonography magnetic resonance imaging

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

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

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：