检索结果-南通市图书馆

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

桥式推挽结构超声激励电路性能分析

声学技术 2015年第3期34卷 279-282页

作者：安艳芳彭召斌廉国选冷涛王小民中国科学院声学研究所北京100190

基于桥式推挽结构,设计了由两路正向单脉冲电压产生双极性电压效果的电路,提高了激励信号的能量,为超声无损检测激励电路的负向耐压低、供电电源复杂等问题提供了解决方案。该方案包括硬件实现和相关实验验证。脉冲回波检测实验结果证明... 详细信息

基于桥式推挽结构,设计了由两路正向单脉冲电压产生双极性电压效果的电路,提高了激励信号的能量,为超声无损检测激励电路的负向耐压低、供电电源复杂等问题提供了解决方案。该方案包括硬件实现和相关实验验证。脉冲回波检测实验结果证明:桥式推挽结构的超声激励可以提高回波的幅度,在相同实验条件下,回波幅度为单极性方波脉冲激励的两倍,等效于双极性方波脉冲激励的效果。该文方法可以提高超声激励电路的性能,为高性能便捷式超声激励系统的设计提供了理论和实验依据。

关键词：超声检测桥式推挽结构电路性能

Photo‑Energized MoS_(2)/CNT Cathode for High‑Performance Li–CO_(2)Batteries in a Wide‑Temperature Range

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第1期17卷 160-175页

作者： Tingsong Hu Wenyi lian Kang Hu Qiuju Li Xueliang Cui Tengyu Yao Laifa Shen Jiangsu Key Laboratory of Materials and Technologies for Energy Storage College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016People’s Republic of China

Li–CO_(2) batteries are considered promising energy storage systems in extreme environments such as Mars;however,severe performance degradation will occur at a subzero temperature owning to the sluggish reaction ***,a photo-energized strategy adopting sustainable solar energy in wide working temperature range Li–CO_(2) battery was achieved with a binder-free MoS_(2)/carbon nanotube(CNT)photo-electrode as *** unique layered structure and excellent photoelectric properties of MoS_(2) facilitate the abundant generation and rapid transfer of photo-excited carriers,which accelerate the CO_(2) reduction and Li_(2)CO_(3) decomposition upon *** illuminated battery at room temperature exhibited high discharge voltage of 2.95 V and mitigated charge voltage of 3.27 V,attaining superior energy efficiency of 90.2%and excellent cycling stability of over 120 *** at an extremely low temperature of−30℃,the battery with same electrolyte can still deliver a small polarization of 0.45 V by the photoelectric and photothermal synergistic mechanism of MoS_(2)/CNT *** work demonstrates the promising potential of the photo-energized wide working temperature range Li–CO_(2) battery in addressing the obstacle of charge overpotential and energy efficiency.

关键词： Li-CO_(2)batteries Photo-energized Wide operation-temperature Kinetics MoS_(2)

Dynamical complexity of Anosov systems driven by a quasi-periodic force

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2025年第1期 89-136页

作者： Wen Huang Zeng lian Kening Lu Department of Mathematics University of Science and Technology of China School of Mathematics Sichuan University

Consider C2Anosov systems on a compact manifold driven by a quasi-periodic *** study their dynamical complexity on various levels from the perspectives of both path-wise dynamics and stochastic *** that these systems are non-wandering（i.e.,every point in the phase space is nonwandering）,we prove a set of results:（1） the existence of abundance of random periodic points;（2） a random Liv?ic theorem;（3） a random Ma?é-Bousch-Conze-Guivarc'h lemma;（4） the existence of strong random ***,a concrete example constructed on a 2-dimensional torus is also given to uncover some interesting phenomena of the systems.

关键词：

同方期刊数据库

Multifunctional Nacre‑Like Nanocomposite Papers for Electromagnetic Interference Shielding via Heterocyclic Aramid/MXene Template‑Assisted In‑Situ Polypyrrole Assembly

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第3期17卷 37-54页

作者： Jinhua Xiong Xu Zhao Zonglin Liu He Chen Qian Yan Huanxin lian Yunxiang Chen Qingyu Peng Xiaodong He National Key Laboratory of Science and Technology On Advanced Composites in Special Environments Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin 150080People’s Republic of China

Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic *** this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.

关键词： MXene Remarkable mechanical properties Heterocyclic aramid Electromagnetic interference shielding Polypyrrole Multifunctionality

Thermal Feature Analysis of a New Hot-Air Anti-Icing Structure

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

Journal of Thermal Science 2023年第3期32卷 911-921页

作者： lianG Jiuli xuan Yimin lian Wenlei School of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Thermal Management and Energy Utilization of Aviation Vehicles Ministry of Industry and Information TechnologyNanjing 210016China

Ice accretion on surfaces of the aircraft and engine is a serious threat to the flight *** this paper,a novel hot air anti-icing method is proposed based on the porous *** the NACA0012 airfoil as an example,the traditional thermal protection structure is proved to exist the deficiency in balancing the heat exchange caused by route loss of the *** dividing the hot chamber into multiple regions to fill with various foam metal,flow resistance characteristics and heat transfer characteristics for this protection mode are analyzed in order to derive the maximized benefit in anti-icing *** calculation results reveal that,under the same condition,the region filled with foamed copper not only improves the temperature uniformity on the anti-icing area,but also achieves a better protection effect for enhancing heat transfer between the tube and the hot gas,averagely above 20℃higher than it without porous foam filling in surface ***,the minimum mass flow rate of the protection hot air is reduced by 16.7%.The gratifying efficiency of the porous filler in fortifying heat transfer confirms the potential of replacing the efficient but complex heat transfer design with simple structure filled with foam metal.

关键词： ice accretion hot air anti-icing foam metal heat transfer

Numerical Aspects of Isogeometric Boundary Element Methods:(Nearly)Singular Quadrature,Trimmed NURBS and Surface Crack Modeling

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2022年第1期130卷 513-542页

作者： xuan Peng Haojie lian Department of Mechanical Engineering Suzhou University of Science and TechnologySuzhou215009China Key Laboratory of In-situ Property-improving Mining of Ministry of Education Taiyuan University of TechnologyTaiyuan030024China

This work presents some numerical aspects of isogeometric boundary element methods(IGABEM).The behavior of hyper-singular and nearly-singular integration is first explored on the distorted NURBS *** numerical treatments are proposed to enhance the quadrature in the framework of isogeometric *** a numerical implementation of IGABEM on the trimmed NURBS is *** on this idea,the surface crack problem is modeled incorporation with the phantom element *** proposed method allows the crack to intersect with the boundary of the body while preserving the original parametrization of the NURBS-based CAD geometry.

关键词： Isogeometric analysis trimmed NURBS singular integration boundary element method surface crack

A comprehensive set of criteria for evaluating thermal management systems of aerial vehicles

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

Science China(Technological Sciences) 2023年第7期66卷 2093-2107页

作者： YIN HuiNing xuan YiMin lian WenLei WANG TianYi School of Energy and Power Engineering Aero-engine Thermal Environment and Structure Key Laboratory of Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China

Thermal management has become a significant concern in the design of advanced air ***,an effective evaluation method is needed when designers need to evaluate aircraft thermal management systems *** paper proposes an evaluation method in which several evaluation directions concerned with thermal management systems(TMSs) are put forward to form an evaluation index *** effect of temperature control,heat sink utilization efficiency,energy utilization efficiency,flight performance penalty,thermal endurance,space occupancy ratio,and economy are chosen as the direction of evaluation for TMS,considering its primary function,system performance,and impact on aerial *** method is comprehensive,intuitive,and user-friendly,along with the intensely subjective user-defined weight parameters,which provide rational metrics for thermal management techniques involved in aerial *** evaluation method could potentially be helpful for designers to comprehensively analyze the performance of aircraft thermal management systems and provide a basis for practical *** examples are provided to demonstrate the application of the method to evaluating TMS comprehensively.

关键词： comprehensive evaluation method evaluation index system aircraft thermal management system

Particle image velocimetry for an automatic cooling device using temperature-sensitive magnetic fluid

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第8期51卷 1203-1210页

作者： lian WenLei LI Qiang xuan YiMin School of Power Engineering Nanjing University of Science&TechnologyNanjing 210094China

An automatic cooling device has been developed by using a temperature-sensitive magnetic fluid as the coolant. A particle image velocimetry (PIV) system was used to measure the flow velocity of the fluid inside the loop. The efficiency of the device under varying conditions such as the heat load and the power of cooling were ex- perimentally investigated. The effect of cooperation between external magnetic field and thermal field on the performance of the device was studied. As expected, a continuous flow induced by the thermal and magnetic field was observed in the loop, where heat was transferred by the circulating magnetic fluid. The synergic effect between the magnetic field and the temperature gradient has impact on the performance of the device.

关键词： temperature-sensitive magnetic fluid automatic cooling device particle image velocimetry (PIV)

Optimal constrained multi-degree reduction of Bézier curves with explicit expressions based on divide and conquer

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 577-582页

作者： lian ZHOU guo-jin WANG Institute of Computer Graphics and Image Processing State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China

We decompose the problem of the optimal multi-degree reduction of Bézier curves with corners constraint into two simpler subproblems, namely making high order interpolations at the two endpoints without degree reduction, and doing optimal degree reduction without making high order interpolations at the two endpoints. Further, we convert the second subproblem into multi-degree reduction of Jacobi polynomials. Then, we can easily derive the optimal solution using orthonormality of Jacobi polynomials and the least square method of unequally accurate measurement. This method of 'divide and conquer' has several advantages including maintaining high continuity at the two endpoints of the curve, doing multi-degree reduction only once, using explicit approximation expressions, estimating error in advance, low time cost, and high precision. More importantly, it is not only deduced simply and directly, but also can be easily extended to the degree reduction of surfaces. Finally, we present two examples to demonstrate the effectiveness of our algorithm.

关键词： Bezier curves Multi-degree reduction Divide and conquer