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Further Results on Stability Analysis for Sampled-Data Systems via Refined Semi-Looped-Functional

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Journal of Systems Science & Complexity 2024年第1期37卷 318-328页

作者： SHENG Zhaoliang XU Shengyuan ma Qian zhang Baoyong School of Automation Nanjing University of Science and TechnologyNanjing 210094China

This paper investigates the stability problem for sampled-data systems by adopting a refined semi-looped-functional,which is with the following two ***,the new functional term is with a new integral vectorη0,which contains sampling information of the systems and associates two commonly used ***,the vectorη0 is combined into various zero equations for processing the functional,especially where a new equation is derived fromη*** on the refined functional,further stability results for sampled-data systems are *** the effectiveness of the results is numerically verified through two examples at the end.

关键词： Integral vector sampled-data systems semi-looped-functional stability analysis.

Sequestration of helium and xenon via iron-halide compounds in early Earth

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matter and Radiation at Extremes 2024年第3期9卷 83-88页

作者： Jurong zhang Hanyu Liu Changfeng Chen Yanming ma Key Laboratory of material Simulation Methods and Software of Ministry of Education and State Key Laboratory of Superhard materials College of PhysicsJilin UniversityChangchun 130012China School of Physics and Electronics Shandong Normal UniversityJinan 250014China International Center of Future Science Jilin UniversityChangchun 130012China Department of Physics and Astronomy University of NevadaLas VegasNevada 89154USA

The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive ***,using an advanced crystal structure search approach in conjunction with first-principles calculations,we show that several Xe/He-bearing iron halides are thermodynamically stable in a broad region of P–T phase space below 60 *** results present a compelling case for sequestration of He and Xe in the early Earth and may suggest their much wider distribution in the present Earth than previously *** findings offer insights into key material-based and physical mechanisms for elucidating major geological phenomena.

关键词： halide searching insight

Lightweight Dual‑Functional Segregated Nanocomposite Foams for Integrated Infrared Stealth and Absorption‑Dominant Electromagnetic Interference Shielding

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Nano-Micro Letters 2024年第11期16卷 38-55页

作者： Zhonglei ma Ruochu Jiang Jiayao Jing Songlei Kang Li ma Kefan zhang Junxian Li Yu zhang Jianbin Qin Shuhuan Yun Guangcheng zhang MOE Key Laboratory of material Physics and Chemistry Under Extraordinary Conditions Shaanxi Key Laboratory of Macromolecular Science and TechnologySchool of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China College of Chemistry and Chemical Engineering Key Laboratory of Auxiliary Chemistry and Technology for Chemical IndustryMinistry of EducationShaanxi University of Science and TechnologyXi’an 710072People’s Republic of China Department of Mechanical and Industrial Engineering University of Toronto5 King’s College RoadTorontoON M5S 3G8Canada Chongqing Innovation Center Northwestern Polytechnical UniversityChongqing 401135People’s Republic of China

Lightweight infrared stealth and absorption-dominant electromagnetic interference(EMI)shielding materials are highly desirable in areas of aerospace,weapons,military and wearable ***,lightweight and high-efficiency dual-functional segregated nanocomposite foams with microcellular structures are developed for integrated infrared stealth and absorption-dominant EMI shielding via the efficient and scalable supercritical CO_(2)(SC-CO_(2))foaming combined with hydrogen bonding assembly and compression molding *** obtained lightweight segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity,and outstanding absorption-dominant EMI shielding performances attributed to the synchronous construction of microcellular structures and segregated ***,the segregated nanocomposite foams present a large radiation temperature reduction of 70.2℃ at the object temperature of 100℃,and a significantly improved EM wave absorptivity/reflectivity(A/R)ratio of 2.15 at an ultralow Ti_(3)C_(2)T_(x) content of 1.7 vol%.Moreover,the segregated nanocomposite foams exhibit outstanding working reliability and stability upon dynamic compression *** results demonstrate that the lightweight and high-efficiency dual-functional segregated nanocomposite foams have excellent potentials for infrared stealth and absorption-dominant EMI shielding applications in aerospace,weapons,military and wearable electronics.

关键词： Segregated nanocomposite foams Microcellular structures Infrared stealth EMI shielding Low infrared emissivity

A Detailed Thermal Resistance Network Analysis of FCBGA Package

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Journal of Thermal Science 2024年第1期33卷 18-28页

作者： DANG Hao LU Yang DU Yanzheng zhang Xiu zhang Qian ma Weigang zhang Xing Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China Zhongxing Telecom Equipment Corporation Shanghai 201203China

Using thermal models to describe the heat dissipation process of FCBGA is a significant topic in the field of ***,the thermal resistance model considering the structure of each part of the chip is still ambiguous and rare,but it is quite desirable in *** this work,we propose a detailed thermal resistance network model,and describe it by using thermal conduction resistance and thermal spreading *** a striking FCBGA case,we calculated the thermal resistance of each part of the structure according to the temperature field simulated by *** thermal resistance network can be used to predict the temperatures in the chip under different *** example,when the power changes by 40%,the relative error of junction temperature prediction is only 0.24%.The function of the detailed thermal resistance network in evaluating the optimization space and determining the optimization direction is *** work illustrates a potential thermal resistance analysis method for electronic devices such as FCBGA.

关键词： FCBGA package thermal resistance network thermal spreading resistance junction temperature

Interface Engineering of Titanium Nitride Nanotube Composites for Excellent Microwave Absorption at Elevated Temperature

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Nano-Micro Letters 2024年第9期16卷 147-160页

作者： Cuiping Li Dan Li Shuai zhang Long ma Lei zhang Jingwei zhang Chunhong Gong College of Chemistry and Molecular Sciences Henan UniversityKaifeng 475004People’s Republic of China National and Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials Henan UniversityKaifeng 475004People’s Republic of China

Currently,the microwave absorbers usually suffer dreadful electromagnetic wave absorption(EMWA)performance damping at elevated temperature due to impedance mismatching induced by increased conduction ***,the development of high-performance EMWA materials with good impedance matching and strong loss ability in wide temperature spectrum has emerged as a top ***,due to the high melting point,good electrical conductivity,excellent environmental stability,EM coupling effect,and abundant interfaces of titanium nitride(TiN)nanotubes,they were designed based on the controlling kinetic diffusion procedure and Ostwald ripening *** from boosted heterogeneous interfaces between TiN nanotubes and polydimethylsiloxane(PDMS),enhanced polarization loss relaxations were created,which could not only improve the depletion efficiency of EMWA,but also contribute to the optimized impedance matching at elevated ***,the TiN nanotubes/PDMS composite showed excellent EMWA performances at varied temperature(298-573 K),while achieved an effective absorption bandwidth(EAB)value of 3.23 GHz and a minimum reflection loss(RLmin)value of−44.15 dB at 423 *** study not only clarifies the relationship between dielectric loss capacity(conduction loss and polarization loss)and temperature,but also breaks new ground for EM absorbers in wide temperature spectrum based on interface engineering.

关键词： TiN nanotubes Interface engineering Polarization loss Impedance matching Electromagnetic wave absorption performance

Surface-induced interaction of colloidal particles in isotropic liquid crystals

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Communications in Theoretical Physics 2024年第7期76卷 114-122页

作者： Hualing zhang Kaifeng Weng Rui ma Department of Physics College of Physical Science and TechnologyXiamen UniversityXiamen 361005China Fujian Provincial Key Laboratory for Soft Functional materials Research Research Institute for Biomimetics and Soft MatterXiamen UniversityXiamen 361005China

In this work,we study the interaction between two colloidal particles in a liquid crystal that is in the isotropic *** interaction is caused by surface-induced polarization of the liquid crystal molecules in the vicinity of the *** find that the interaction is short-ranged in both 2D and 3D *** symmetric homeotropic anchoring conditions,the interaction is *** under anti-symmetric homeotropic anchoring conditions,the interaction is repulsive at short distances but attractive at intermediate *** particle size has a strong impact on the effective interaction force.

关键词： surface-induced interaction colloidal particles liquid crystals

Effect of Shape and Placement of Twisted Pin Fins in a Rectangular Channel on Thermo-Hydraulic Performance

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Journal of Thermal Science 2024年第5期33卷 1773-1793页

作者： LI Yong zhang Jin zhang Yingchun zhang Jiajie ma Suxia SUNDEN Bengt XIE Gongnan College of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Cleaner Intelligent Control on Coal&Electricity Ministry of EducationTaiyuan 030024China Shanxi Provincial Key Laboratory of High Efficiency Heat Storage and Low Carbon Heat Supply Taiyuan 030008China School of Energy and Power Engineering North University of ChinaTaiyuan 030051China Department of Energy Sciences Lund UniversityP.O.Box 118Lund SE 22100Sweden School of marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China

To enhance the thermo-hydraulic performance of cooling channels,this investigation examines the influence of distinct cross-sectional shapes(i.e.,triangular,rectangular,and hexagonal)of twisted pin fins and their arrangements in straight and cross *** ambient air cooling test platform was established to numerically and experimentally investigate the flow and heat transfer characteristics of 360°twisted pin fins at Re=*** findings reveal that straight rows exhibit higher Nu values than cross rows for triangular and rectangular twisted pin fins,and Nu increases with *** contrast,for hexagonal twisted pin fins,only straight rows at Re=19000 exhibit superior overall thermal performance compared to cross ***,the heat transfer performance of the cooling channel with hexagonal twisted fins surpasses both triangular and rectangular configurations,especially at high Reynolds numbers(Re=22800).Although the heat transfer coefficient of the cooling channel with hexagonal twisted fins is significantly enhanced by 132.71%compared to the flat channel,it also exhibits the highest thermal resistance and relative friction among the three types of twisted fins,the maximum of which are 2.14 and ***,the hydrothermal performance factor(HTPF)of the cooling channels with different types of twisted pin fins depends on the Reynolds number and arrangement *** Re=15200,the highest HTPF achieved for the cross-row hexagonal twisted pin fins is 0.99.

关键词： twisted pin fin cross arrangement heat transfer pressure drop HTPF

Directly predicting N_(2) electroreduction reaction free energy using interpretable machine learning with non-DFT calculated features

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Journal of Energy Chemistry 2024年第10期97卷 139-148,I0004页

作者： Yaqin zhang Yuhang Wang Ninggui ma Jun Fan Department of materials Science and Engineering City University of Hong KongHong Kong 999077China Center for Advanced Nuclear Safety and Sustainable Development City University of Hong KongHong Kong 9077China Department of Mechanical Engineering City University of Hong KongHong Kong 999077China

Electrocatalytic nitrogen reduction to ammonia has garnered significant attention with the blooming of single-atom catalysts(SACs),showcasing their potential for sustainable and energy-efficient ammonia ***,cost-effectively designing and screening efficient electrocatalysts remains a *** this study,we have successfully established interpretable machine learning(ML)models to evaluate the catalytic activity of SACs by directly and accurately predicting reaction Gibbs free *** models were trained using non-density functional theory(DFT)calculated features from a dataset comprising 90 graphene-supported *** results underscore the superior prediction accuracy of the gradient boosting regression(GBR)model for bothΔg(N_(2)→NNH)andΔG(NH_(2)→NH_(3)),boasting coefficient of determination(R^(2))score of 0.972 and 0.984,along with root mean square error(RMSE)of 0.051 and 0.085 eV,***,feature importance analysis elucidates that the high accuracy of GBR model stems from its adept capture of characteristics pertinent to the active center and coordination environment,unveilling the significance of elementary descriptors,with the colvalent radius playing a dominant ***,Shapley additive explanations(SHAP)analysis provides global and local interpretation of the working mechanism of the GBR *** analysis identifies that a pyrrole-type coordination(flag=0),d-orbitals with a moderate occupation(N_(d)=5),and a moderate difference in covalent radius(r_(TM-ave)near 140 pm)are conducive to achieving high ***,we extend the prediction of activity to more catalysts without additional DFT calculations,validating the reliability of our feature engineering,model training,and design *** findings not only highlight new opportunity for accelerating catalyst design using non-DFT calculated features,but also shed light on the working mechanism of"black box"ML ***,the model provides valuable g

关键词： Nitrogen reduction Single-atom catalyst Interpretable machine learning Graphene Non-DFT features

Accelerated heterogenous ring-opening polymerization towards well-defined helical poly(N-allyl alanine)with clickable side chains

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Science China Chemistry 2024年第6期67卷 2056-2062页

作者： Anyao ma Xin Wang Sunting Xuan Zhengbiao zhang College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou215123China State Key Laboratory of Radiation Medicine and Protection Soochow UniversitySuzhou215123China

Well-defined poly(N-allyl alanine)has been synthesized by heterogenous ring-opening polymerization(HROP)of less reactive N-allyl-alanine N-carboxyanhydride,using acetic acid as the catalyst and benzylamine as the initiator,in non-polar ***,the polymerization exhibited typical features of living polymerization though both monomer(liquid)and polymer(solid)have minimal solubility in *** obtained polymer showed a stable helix structure independent of the temperatures screened,as evidenced by circular dichroism ***,the preliminary study demonstrated that the side chains can be post-functionalized through thiol-ene click chemistry with quantitative ***,this work provides guidance for the development of accelerated HROP of other liquid monomers bearing low ***,the helical and functionalizable poly(N-allyl alanine)could be a useful“clickable platform”for the design of variable biomaterials via efficient click chemistry.

关键词： heterogenous ring-opening polymerization controlled polymerization stable helix clickable N-substituted polypeptide di-substituted polypeptoid