检索结果-南通市图书馆

Preface for the Special Issue on“Safety and Intelligent Maintenance of Offshore Structures”

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

China Ocean Engineering 2024年第2期38卷 181-182页

作者： xu wan-hai State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300072China

The ocean serves as a vital carrier for human resource development and economic growth and contains rich mineral resources such as oil,natural gas,polymetallic nodules,cobalt-rich ferromanganese crusts,polymetallic sulfides,and rare earth ***,the ocean has wealthy reserves of wind,wave,tidal,and solar energy,making it an essential strategic space for sustainable future ***,offshore structures are complex.

关键词： ocean offshore tidal

A Review on Vibration Control of Multiple Cylinders Subjected to FlowInduced Vibrations

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第2期38卷 183-197页

作者： xu wan-hai MA Ye-xuan State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300350China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China

The fatigue damage caused by flow-induced vibration(FIV)is one of the major concerns for multiple cylindrical structures in many engineering *** FIV suppression is of great importance for the security of many cylindrical *** active and passive control methods have been employed for the vibration suppression of an isolated cylinder undergoing vortex-induced vibrations(VIV).The FIV suppression methods are mainly extended to the multiple cylinders from the vibration control of the isolated *** to the mutual interference between the multiple cylinders,the FIV mechanism is more complex than the VIV mechanism,which makes a great challenge for the FIV *** efforts have been devoted to vibration suppression of multiple cylinder systems undergoing FIV over the past two *** control methods,such as helical strakes,splitter plates,control rods and flexible sheets,are not always effective,depending on many influence factors,such as the spacing ratio,the arrangement geometrical shape,the flow velocity and the parameters of the vibration control *** FIV response,hydrodynamic features and wake patterns of the multiple cylinders equipped with vibration control devices are reviewed and *** FIV suppression efficiency of the vibration control methods are analyzed and compared considering different influence *** research on the FIV suppression of multiple cylinders is suggested to provide insight for the development of FIV control methods and promote engineering applications of FIV control methods.

关键词： flow-induced vibration vibration control multiple cylinders tandem side-by-side staggered

The prediction on in-line vortex-induced vibration of slender marine structures

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第5期28卷 1303-1308页

作者： wan-hai xu Xi-Feng Gao Jie Du State Key Laboratory of Hydraulic Engineering Simulation and Safety School of Civil EngineeringTianjin University

The in-line （IL） vortex-induced vibration （VIV） that occurs frequently in ocean engineering may cause severe fatigue damage in slender marine structures. To the best knowledge of the authors, in existing literatures, there is no efficient analytical model for predicting pure IL VIV. In this paper, a wake oscillator model capable of analyzing the IL VIV of slender marine structures has been developed. Two different kinds of van der Pol equations are used to describe the near wake dynamics related to the fluctuating nature of symmetric vortex shedding in the first excitation region and alternate vortex shedding in the second one. Some comparisons are carried out between the present model results and experimental data. It is found that many phenomena observed in experiments could be reproduced by the present wake oscillator model.

关键词： Vortex-induced vibration Wake oscillatormodel In-line Slender marine structures

Whispering-gallery-mode barcode-based broadband sub-femtometer-resolution spectroscopy with an electro-optic frequency comb

在线全文

学校读者我要写书评

暂无评论

Advanced Photonics 2024年第1期6卷 115-125页

作者： Bingxin xu Yangyang wan Xinyu Fan Zuyuan He Shanghai Jiao Tong University State Key Laboratory of Advanced Optical Communication Systems and NetworksDepartment of Electronic EngineeringShanghaiChina Max-Planck Institute of Quantum Optics Hans-Kopfermann-Straûe 185748 GarchingGermany

Spectroscopy is the basic tool for studying molecular physics and realizing biochemical ***,it is challenging to realize sub-femtometer resolution spectroscopy over broad *** and high-resolution spectroscopy with calibrated optical frequency is demonstrated by bridging the fields of speckle pattern and electro-optic frequency comb.A wavemeter based on a whispering-gallery-mode barcode is proposed to link the frequencies of a probe continuous-wave laser and an ultrastable *** ultrafine electro-optic comb lines are generated from the probe laser to record spectrum of sample with sub-femtometer *** bandwidth is a thousandfold broader than comb bandwidth,by sequentially tuning the probe laser while its wavelength is *** approach fully exploits the advantages of two fields to realize 0.8-fm resolution with a fiber laser and 80-nm bandwidth with an external cavity diode *** spectroscopic measurements of an ultrahigh Q-factor cavity and gas molecular absorption are experimentally *** compact system,predominantly constituted by few-gigahertz electronics and telecommunication components,shows enormous potential for practical spectroscopic applications.

关键词： frequency comb reconstructive wavemeter spectroscopy

An effective catalyst carrier SiO_(2):Enhancing catalytic and combustion properties of CuFe_(2)O_(4)on energetic components

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第2期32卷 383-392页

作者： Li Ding Chong wan Suhang Chen Zhao Qin Kangzhen xu School of Chemical Engineering/Xi'an Key Laboratory of Special Energy Materials Northwest UniversityXi'an710069China Xi’an Modern Chemistry Research Institute Xi'an710065China

To enhance the catalytic activity of copper ferrite(CuFe_(2)O_(4))nanoparticle and promote its application as combustion catalyst,a low-cost silicon dioxide(SiO_(2))carrier was employed to construct a novel CuFe_(2)O_(4)/SiO_(2)binary composites via solvothermal *** phase structure,morphology and catalytic activity of CuFe_(2)O_(4)/SiO_(2)composites were studied firstly,and thermal decomposition,combustion and safety performance of ammonium perchlorate(AP)and 1,3,5-trinitroperhydro-1,3,5-triazine(RDX)with it affecting were then systematically *** results show that CuFe_(2)O_(4)/SiO_(2)composite can remarkably either advance the decomposition peak temperature of AP and RDX,or reduce the apparent activation energy at their main decomposition ***,the flame propagation rate of RDX was promoted by about 2.73 times with SiO_(2)content of 3 wt%,and safety property of energetic component was also improved greatly,in which depressing the electrostatic discharge sensitivity of pure RDX by about 1.89 *** addition,the effective range of SiO_(2)carrier content in the binary catalyst is found to be 3 to 5 wt%.Therefore,SiO_(2)opens a new insight on the design of combustion catalyst carrier and will promote the application of CuFe_(2)O_(4)catalyst in solid propellant.

关键词： Copper ferrite Silicon dioxide Combustion catalyst Thermal decomposition Laser ignition

Spatial correlations in time and frequency domains between chlorophyll-a concentration and environmental factors in the Bohai Sea

在线全文

学校读者我要写书评

暂无评论

JOURNAL OF OCEANOLOGY AND LIMNOLOGY 2024年第4期42卷 1-14页

作者： xu, wan Mu, Di Yang, Zhenteng Yuan, Dekui Tianjin Univ Dept Mech Tianjin 300350 Peoples R China Hebei Univ Technol Engn Res Ctr Seawater Utilizat Technol Minist Educ Sch Chem Engn & Technol Tianjin 300130 Peoples R China Tianjin Univ State Key Lab Hydraul Engn Simulat & Safety Tianjin 300072 Peoples R China

Based on the reconstructed MODIS data and ECMWF reanalysis data from 2003 to 2021, spatial correlations between chlorophyll a (Chl a) and sea surface temperature (SST), photosynthetically available radiation (PAR), aerosol optical thickness (AOT), and wind speed (WS) in the Bohai Sea were analyzed from the perspective of time domain and frequency domain. Results indicate that the frequency-domain analysis was more conducive to revealing the correlations between Chl a and environmental factors. The spatial pattern of time-domain correlations was similar to the isobaths of the Bohai Sea, which was positive in shallow waters and negative in deep waters for SST, PAR, and AOT, and was reversed for WS. Frequency-domain correlations were obtained by performing Fourier Transform and were higher than correlations in time domain. The spatial distributions indicated that the effects of SST and PAR on Chl a were greater than AOT and WS in the Bohai Sea. Additionally, cross-spectrum analysis was applied to explore the response relationships. A depth-dependent pattern was shown in correlations and time lags, indicating that the influential mechanism of environmental factors on Chl-a concentration is related to seawater depth.

关键词： chlorophyll a (Chl a) frequency domain spatial correlation Bohai Sea SURFACE TEMPERATURE SST PHYTOPLANKTON IMPACT BAY

A Cross-matching Service for Data Center of Xinjiang Astronomical Observatory

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

Research in Astronomy and Astrophysics 2024年第1期24卷 119-127页

作者： hai-Long Zhang Jie wang Xin-Chen Ye wan-Qiong wang Jia Li Ya-Zhou Zhang xu Du Han Wu Ting Zhang Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China National Astronomical Data Center Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Cross-matching is a key technique to achieve fusion of multi-band astronomical catalogs. Due to different equipment such as various astronomical telescopes, the existence of measurement errors, and proper motions of the celestial bodies, the same celestial object will have different positions in different catalogs, making it difficult to integrate multi-band or full-band astronomical data. In this study, we propose an online cross-matching method based on pseudo-spherical indexing techniques and develop a service combining with high performance computing system(Taurus) to improve cross-matching efficiency, which is designed for the Data Center of Xinjiang Astronomical Observatory. Specifically, we use Quad Tree Cube to divide the spherical blocks of the celestial object and map the 2D space composed of R.A. and decl. to 1D space and achieve correspondence between real celestial objects and spherical patches. Finally, we verify the performance of the service using Gaia 3 and PPMXL catalogs. Meanwhile, we send the matching results to VO tools-Topcat and Aladin respectively to get visual results. The experimental results show that the service effectively solves the speed bottleneck problem of crossmatching caused by frequent I/O, and significantly improves the retrieval and matching speed of massive astronomical data.

关键词： virtual observatory tools astronomical databases:miscellaneous catalogs

Atom substitution of the solid-state electrolyte Li_(10)GeP_(2)S_(12)for stabilized all-solid-state lithium metal batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第1期88卷 28-38,I0002页

作者： Zijing wan Xiaozhen Chen Ziqi Zhou Xiaoliang Zhong Xiaobing Luo Dongwei xu State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina

Solid-state electrolyte Li_(10)GeP_(2)S_(12)(LGPS)has a high lithium ion conductivity of 12 mS cm^(-1)at room temperature,but its inferior chemical stability against lithium metal anode impedes its practical *** all solutions,Ge atom substitution of the solid-state electrolyte LGPS stands out as the most promising solution to this interface problem.A systematic screening framework for Ge atom substitution including ionic conductivity,thermodynamic stability,electronic and mechanical properties is utilized to solve *** fast screening,an enhanced model Dop Net FC using chemical formulas for the dataset is adopted to predict ionic ***,Li_(10)SrP_(2)S_(12)(LSrPS)is screened out,which has high lithium ion conductivity(12.58 mS cm^(-1)).In addition,an enhanced migration of lithium ion across the LSr PS/Li interface is ***,compared to the LGPS/Li interface,LSrPS/Li interface exhibits a larger Schottky barrier(0.134 eV),smaller electron transfer region(3.103?),and enhanced ability to block additional electrons,all of which contribute to the stabilized *** applied theoretical atom substitution screening framework with the aid of machine learning can be extended to rapid determination of modified specific material schemes.

关键词： Atom substitution Solid-state electrolyte Machine learning Stabilized interface

Predicting PM_(2.5) Concentration in the Yangtze River Delta Region Using Climate System Monitoring Indices and Machine Learning

在线全文

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2024年第2期38卷 249-261页

作者： Jinghui MA Shiquan wan Shasha xu Chanjuan wanG Danni QIU Shanghai Typhoon Institute Shanghai Meteorological ServiceShanghai 200030 Key Laboratory of Polar Atmosphere-Ocean-Iice System for Weather and Climate Ministry of EducationDepartment of Atmospheric and Oceanic SciencesFudan UniversityShanghai 200438 Shanghai Key Laboratory of Meteorology and Health Shanghai Meteorological ServiceShanghai 200030 Yangzhou Meteorological Office Yangzhou 225001 Department of Physics Yangzhou UniversityYangzhou 225003

Changing meteorological conditions during autumn and winter have considerable impact on air quality in the Yangtze River Delta(YRD)*** climatic factors,such as sea surface temperature and sea ice,together with the atmospheric circulation,directly affect meteorological conditions in the YRD region,thereby modulating the variation in atmospheric PM_(2.5) *** study used the evolutionary modeling machine learning technique to investigate the lag relationship between 144 climate system monitoring indices and autumn/winter PM_(2.5) concentration over 0-12 months in the YRD *** calculating the contribution ratios and lagged correlation coefficients of all indices over the previous 12 months,the top 36 indices were selected for model ***,the nine indices that contributed most to the PM_(2.5) concentration in the YRD region,including the decadal oscillation index of the Atlantic Ocean and the consistent warm ocean temperature index of the entire tropical Indian Ocean,were selected for physical mechanism *** evolutionary model was developed to forecast the average PM_(2.5) concentration in major cities of the YRD in autumn and winter,with a correlation coefficient of *** model testing,the correlation coefficient between the predicted and observed PM_(2.5) concentrations was in the range of 0.73-0.83 and the root-mean-square error was in the range of 9.5-11.6μg m-3,indicating high predictive *** model performed exceptionally well in capturing abnormal changes in PM_(2.5) concentration in the YRD region up to 50 days in advance.

关键词： PM_(2.5)concentration machine learning evolutionary modeling seasonal prediction