检索结果-南通市图书馆

China Ocean Engineering 2024年第2期38卷 285-296页

作者： DU Zun-feng ZHU hai-ming YU Jian-xing State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation School of Civil EngineeringTianjin UniversityTianjin 300350China

When investigating the vortex-induced vibration(VIV)of marine risers,extrapolating the dynamic response on the entire length based on limited sensor measurements is a crucial step in both laboratory experiments and fatigue monitoring of real risers.The problem is conventionally solved using the modal decomposition method,based on the principle that the response can be approximated by a weighted sum of limited vibration modes.However,the method is not valid when the problem is underdetermined,i.e.,the number of unknown mode weights is more than the number of known measurements.This study proposed a sparse modal decomposition method based on the compressed sensing theory and the Compressive Sampling Matching Pursuit(Co Sa MP)algorithm,exploiting the sparsity of VIV in the modal space.In the validation study based on high-order VIV experiment data,the proposed method successfully reconstructed the response using only seven acceleration measurements when the conventional methods failed.A primary advantage of the proposed method is that it offers a completely data-driven approach for the underdetermined VIV reconstruction problem,which is more favorable than existing model-dependent solutions for many practical applications such as riser structural health monitoring.

关键词： motion reconstruction vortex-induced vibration(VIV) marine riser modal decomposition method compressed sensing

Nanofabricated high turn-density spiral coils for on-chip electromagneto-optical conversion

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第2期10卷 181-192页

作者： Ilhan Bok Alireza Ashtiani Yash Gokhale Jack Phillips Tianxiang Zhu Aviad hai Department of Biomedical Engineering University of Wisconsin–MadisonMadisonWIUSA Department of Electrical and Computer Engineering University of Wisconsin–MadisonMadisonWIUSA Wisconsin Institute for Translational Neuroengineering(WITNe) University of Wisconsin–MadisonMadisonWIUSA

Circuit-integrated electromagnets are fundamental building blocks for on-chip signal transduction,modulation,and tunability,with specific applications in environmental and biomedical micromagnetometry.A primary challenge for improving performance is pushing quality limitations while minimizing size and fabrication complexity and retaining spatial capabilities.Recent efforts have exploited highly involved three-dimensional synthesis,advanced insulation,and exotic material compositions.Here,we present a rapid nanofabrication process that employs electron beam dose control for high-turn-density diamond-embedded flat spiral coils;these coils achieve efficient on-chip electromagnetic-to-optical signal conversion.Our fabrication process relies on fast 12.3 s direct writing on standard poly(methyl methacrylate)as a basis for the metal lift-off process.Prototypes with 70 micrometer overall diameters and 49–470 nm interturn spacings with corresponding inductances of 12.3–12.8 nH are developed.We utilize optical micromagnetometry to demonstrate that magnetic field generation at the center of the structure effectively correlates with finite element modeling predictions.Further designs based on our process can be integrated with photolithography to broadly enable optical magnetic sensing and spin-based computation.

关键词： utilize retaining high

Ferromagnetism and insulating behavior with a logarithmic temperature dependence of resistivity in Pb_(10-x)Cux(PO_(4))_(6)O

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(Physics,Mechanics & Astronomy) 2024年第1期67卷 106-111页

作者： Yuhang Zhang Cong Liu Xiyu Zhu hai-Hu Wen Center for Superconducting Physics and Materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Recent claim of discovering above-room-temperature superconductivity(Tc≈400 K)at ambient pressure in copper doped apatite Pb10(PO_(4))_(6)O has stimulated world-wide enthusiasm and impulse of motion.A lot of follow-up works have been carried out with controversial conclusions.To check whether superconductivity is really present or absent in the material,we need samples which should have a rather pure phase of Pb_(10-x)Cux(PO_(4))_(6)O.Here we report the characterization results from the Pb_(10-x)Cux(PO_(4))_(6)O with a fraction of about 97 wt.%inferred from the fitting to the X-ray diffraction pattern,if assuming Cu2S as the only impurity.The resistivity measurements show that it is a semiconductor characterized roughly by a ln(1/T)temperature dependence in wide temperature region without trace of superconductivity.Magnetization measurements show that it has a general ferromagnetic signal with a weak superparamagnetic background.Many grains of the sample show clear interactions with a Nb Fe B magnet.The detected Cu concentration is much lower than the expected nominal one.Our results show the absence of metallicity and superconductivity in Pb_(10-x)Cux(PO_(4))_(6)O at ambient pressure,and suggest the presence of strong correlation effect.

关键词： superconductivity Pb10(PO4)6O ferromagnetic correlation effect

Frontiers and future perspectives of neuroimmunology

在线全文

学校读者我要写书评

暂无评论

Fundamental Research 2024年第2期4卷 206-217页

作者： hai Qi Shumin Duan Yanying Xu Hongliang Zhang School of Medicine Tsinghua UniversityBeijing 100084China Faculty of Medicine and Pharmaceutical Sciences Zhejiang UniversityHangzhou 310014China Department of Life Sciences National Natural Science Foundation of ChinaBeijing 100085China

Neuroimmunology is an interdisciplinary branch of biomedical science that emerges from the intersection of studies on the nervous system and the immune system.The complex interplay between the two systems has long been recognized.Research efforts directed at the underlying functional interface and associated pathophysiology,however,have garnered attention only in recent decades.In this narrative review,we highlight significant advances in research on neuroimmune interplay and modulation.A particular focus is on early-and middle-career neuroimmunologists in China and their achievements in frontier areas of"neuroimmune interface","neuro-endocrine-immune network and modulation","neuroimmune interactions in diseases","meningeal lymphatic and glymphatic systems in health and disease",and"tools and methodologies in neuroimmunology research".Key scientific questions and future directions for potential breakthroughs in neuroimmunology research are proposed.

关键词： Neuroimmunology Neuroimmune interplay Neuro-endocrine-immune network Basic research Key scientific questions

Transfer of Highest Weight Modules and Small Unipotent Representations

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

Acta Mathematica Sinica,English Series 2024年第3期40卷 772-791页

作者： hai An HE Jing Song HUANG Kayue Daniel WONG Department of Mathematics College of SciencesShanghai UniversityShanghai 200444P.R.China Newtouch Center for Mathematics of Shanghai University Shanghai 200444P.R.China Mathematics Research Center School of Science and EngineeringThe Chinese University of Hong KongShenzhen 518172P.R.China

We study the transfer between small special unipotent representations for all equal rank real forms of type E_(6) and E_(7). As a consequence, one can verify these modules are unitarity using the results of Wallach an... 详细信息

关键词： Unipotent representations Wallach representations Transfer of unitary modules

Nanocrystalline WSe_(2)excels at high-performance anode for Na storage via a facile one-pot hydrothermal method

在线全文

学校读者我要写书评

暂无评论

Tungsten 2024年第1期6卷 248-258页

作者： hai-Yan Zou Lei Fang Gang Yu Dong Wang State Key Laboratory of Chem/Bio-Sensing and Chemometrics Provincial Hunan Key Laboratory for Graphene Materials and DevicesCollege of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Changxing County Quality and Technology Supervision and Testing Center Huzhou 313100China

For the next large-scale energy storage systems,sodium-ion batteries(SIBs)with excellent electrochemical performance are promising.However,the exploration of anode materials with high specific capacity,fascinating cycling stability and rate capability is still restricted.Among transition metal dichalcogenides(TMDs),tungsten diselenide(WSe_(2))has been regarded as an effective anode material for SIBs and has been extensively studied,due to high theoretical capacity and unique twodimensional layered structure.Herein,nanocrystalline WSe_(2)is prepared by a facile one-pot hydrothermal method.Compared with the micro-scale WSe_(2),benefiting from the high specific surface area of highly ordered nano-flake structures and short ion/electron transport paths,nanocrystalline WSe_(2)shows excellent electrochemical performance in Na storage.After 1000 cycles at a current density of 2 A·g^(-1),a high specific capacity of 264.4 mA·h·g^(-1)is still maintained.The full cell matched with the Na_(3)V_(2)(PO_(4))_(3) cathode can deliver an excellent reversible specific capacity of 196.5 mA·h·g^(-1)after 100 cycles at 0.5 A·g^(-1).

关键词： Tungsten diselenide Transition metal dichalcogenides Hydrothermal Sodium-ion batteries Layered structure

Differential Evolution Hemivariational Inequalities with Anti-periodic Conditions

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第4期40卷 1143-1160页

作者： Jing ZHAO Chun Mei GAN Zhen hai LIU School of Mathematics and Quantitative Economics Guangxi University of Finance and EconomicsNanning 530003P.R.China Guangxi Colleges and Universities Key Laboratory of Optimization Control and Engineering Calculation Guangxi Minzu UniversityNanning 530006P.R.China

The goal of this paper is to deal with a new dynamic system called a differential evolution hemivariational inequality(DEHVI)which couples an abstract parabolic evolution hemivariational inequality and a nonlinear differential equation in a Banach space.First,by apply ing surjectivity result for pseudomonotone multivalued mappins and the properties of Clarke's subgradient,we show the nonempty of the solution set for the parabolic hemivariational inequality.Then,some topological properties of the solution set are established such as boundedness,closedness and convexity.Furthermore,we explore the upper semicontinuity of the solution mapping.Finally,we prove the solution set of the system(DEHVI)is nonempty and the set of all trajectories of(DEHVI)is weakly compact in C(I,X).

关键词： Differential parabolic hemivariational inequality Clarke subdifferential hyperbolicparabolic system parabolic-parabolic system existence result

Paraffin–CaCl_(2)·6H_(2)O dosage effects on the strength and heat transfer characteristics of cemented tailings backfill

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 60-70页

作者： hai Li Aibing Jin Shuaijun Chen Yiqing Zhao You Ju Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine University of Science and Technology BeijingBeijing 100083China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China

The challenge of high temperatures in deep mining remains harmful to the health of workers and their production efficiency The addition of phase change materials (PCMs) to filling slurry and the use of the cold storage function of these materials to reduce downhole temperatures is an effective approach to alleviate the aforementioned problem.Paraffin–CaCl_(2)·6H_(2)O composite PCM was prepared in the laboratory.The composition,phase change latent heat,thermal conductivity,and cemented tailing backfill (CTB) compressive strength of the new material were studied.The heat transfer characteristics and endothermic effect of the PCM were simulated using Fluent software.The results showed the following:(1) The new paraffin–CaCl_(2)·6H_(2)O composite PCM improved the thermal conductivity of native paraffin while avoiding the water solubility of CaCl_(2)·6H_(2)O.(2) The calculation formula of the thermal conductivity of CaCl_(2)·6H_(2)O combined with paraffin was deduced,and the reasons were explained in principle.(3) The“enthalpy–mass scale model”was applied to calculate the phase change latent heat of nonreactive composite PCMs.(4)The addition of the paraffin–CaCl_(2)·6H_(2)O composite PCM reduced the CTB strength but increased its heat absorption capacity.This research can give a theoretical foundation for the use of heat storage backfill in green mines.

关键词： paraffin–CaCl_(2)·6H_(2)O heat transfer simulation heat calculation phase change material-based backfill latent heat of formula

Species profile and reactivity of volatile organic compounds emission in solvent uses,industry activities and from vehicular tunnels

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第1期135卷 546-559页

作者： haimei Huang Zhangwei Wang Chunhao Dai hai Wu Jia Guo Chunjie Wang Xiaoshan Zhang State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Hunan Agricultural University Changsha 430106China National Institute of Metrology Beijing 100029China

A survey was conducted of the volatile organic compounds(VOCs)released from sources of solvent use,industry activities and vehicle emissions in Guiyang,a capital city of China.Samples were collected by canisters and analyzed by GC-MS-FID.The species profiles of VOCs emitted from sources were obtained.Results showed that xylenes,ethylbenzene,acetone and dichloromethane were the characteristics species for painting,2-propanol and ethyl acetate for printing,α-pinene for solid wood furniture manufacturing,and 2-butanone for biscuit baking.These characteristics species could be as tracers for the sources respectively.In most of samples from the solvent use,the benzene/toluene(B/T)ratio was less than 0.3,indicating that the ratio could be as the indicator for tracing the solvent use related sources.The results also suggested that the toluene/xylene(T/X)ratio be as the indicator to distinguish the VOCs sources of painting(2).Aromatics contributed the most to ozone formation potential(OFP)of most painting and non-paper printing sources,and oxygen-containing VOCs(OVOCs)were major species contributing to OFP of the sources from food production and paper printing.The OFP of the VOCs emissions from vehicle in tunnels and from other manufactures were dominated by both aromatics and alkenes.Theα-pinene could explain 56.94%and 32.54%of total OFP of the VOCs sources from filing cabinet and solid wood furniture manufacturing,which was rarely been involved in previous studies of VOCs source profiles,indicating that the species of concern for VOCs sources are still insufficient at present.

关键词： Volatile organic compounds(VOCs) Species profile BTEX ratio Source reactivity

Laser image refractive index sensor based on the combination of a coreless optical fiber and a digital camera

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2024年

作者： GUO jingzhong LAN Feng CHEN Xiang LIU haifeng Xi'an Institute of Space Radio Technology Key Laboratory of Optoelectronic Sensor and Sensing Network Technology College of Electronic Information and Optical Engineering Nankai University

As a laser passes through a scattering medium， the light interacts with the irregular reflections within the medium， resulting in light scattering and the formation of speckles. In this paper， an image sensor based on the combination of a coreless optical fiber and a digital camera is proposed for liquid refractive index sensing applications. The coreless fiber is used as a sensing unit， and the change in the speckle pattern is measured using the digital correlation method to detect the magnitude of the liquid’s refractive index. The experimental results indicate that the laser image sensing technique is capable of effectively distinguishing liquid samples with refractive indices ranging from 1.3328 to 1.3908， with a sensing sensitivity of -1.306 RIU-1. Moreover， the laser image sensing technique， with its advantages of high experimental reproducibility， simple system design， remote over-control， holds great research significance and potential application in laser communication and sensor integration.

关键词：