期刊文献+
共找到808篇文章
< 1 2 41 >
每页显示 20 50 100
ASYMMETRICAL STRUCTURES OF THE TEMPERATURE AND HUMIDITY OF TROPICAL CYCLONES 被引量:2
1
作者 杨涛 雷小途 汤杰 《Journal of Tropical Meteorology》 SCIE 2016年第3期296-304,共9页
Based on NCEP/CFSR 0.5° reanalysis data and the best track data from the Japan Tokyo Typhoon Center,composite and comparative analyses demonstrate the asymmetrical structures of the temperature and humidity in tr... Based on NCEP/CFSR 0.5° reanalysis data and the best track data from the Japan Tokyo Typhoon Center,composite and comparative analyses demonstrate the asymmetrical structures of the temperature and humidity in tropical cyclones over the Western North Pacific and the South China Sea from 1979 to 2010.The results are shown as follows.(1) With intensifying tropical cyclones,the flow field tends to become gradually more axisymmetric;however,the asymmetry of the specific humidity in the outer regions is more obvious.(2) In general,tropical cyclones have a non-uniform,vertical, "double warm-core" structure.The "warm-cores" in the lower level of weak tropical cyclones and in the higher level of strong tropical cyclones are the stronger of the two.(3) The distribution area of a "warm-core" is enhanced with cyclone intensification and tends to become more axisymmetric.At 200 hPa,the "warm-core" of a weak cyclone has a weak anticyclone in the center,whereas that of a strong cyclone has a weak cyclone in the center.(4)The "wet-core" of a tropical cyclone is primarily located in the lower level(700-850 hPa).With the cyclone's intensification,the intensity of the "wet-core" increases and the scope of the 0.8 g kg^(-1) specific humidity anomaly tends to expand to higher levels.(5) With the cyclone's deepening,the pseudo-equivalent potential temperature at different levels in different regions increases.In addition,the largest warming rates at each intensity level in the different regions occur in the core area,followed in turn by the envelope and outer areas. 展开更多
关键词 TROPICAL CYCLONES asymmetrical structure warm-core wet-core INTENSITY
下载PDF
AN ANALYSIS OF THE ASYMMETRICAL STRUCTURE OF TYPHOON AERE'S PRECIPITATION 被引量:2
2
作者 濮江平 吕梅 邹力 《Journal of Tropical Meteorology》 SCIE 2010年第1期91-95,共5页
The structural characteristics of 2004 typhoon Aere's precipitation are analyzed using the high-resolution data from the Tropical Rainfall Measuring Mission(TRMM) of the National Aeronautics Space Administration(N... The structural characteristics of 2004 typhoon Aere's precipitation are analyzed using the high-resolution data from the Tropical Rainfall Measuring Mission(TRMM) of the National Aeronautics Space Administration(NASA).It is found that the typhoon's characteristics vary at different stages of its development.To analyze the asymmetric causation of precipitation distribution,data from the National Center for Environmental Prediction(NCEP) reanalysis are used to calculate the vertical integral of the water vapor flux vector.The results show that because of this process,along with the unique phenomenon of twin-typhoon circulation,the easterly air current of the typhoon's northern side and the southwesterly air current of its southern side play a joint role in transporting water vapor.Furthermore,its transport effects vary greatly at the different stages of development,showing the peculiarity of the water source for this typhoon process.The distributions of the typhoon convection area—characterized by heavy precipitation and a maximum-value area of the water vapor flux,as well as a strong ascending-motion area—differ at different stages of the typhoon's development.The non-uniform distribution of water vapor flux and the vertical motion bring about asymmetrical distribution of the typhoon precipitation. 展开更多
关键词 typhoon precipitation TRMM vapor flux vector asymmetrical structure
下载PDF
A Numerical Study on the Water Impact of the Rigid/Elastic Box-Like Structure
3
作者 YANG Jian SUN Zhao-chen LIANG Shu-xiu 《China Ocean Engineering》 SCIE EI CSCD 2023年第2期333-342,共10页
Recent damages to the box-like structures caused by wave slamming have made it necessary to study the impact problems of this kind of structure. This paper showed findings from numerical simulations of the rigid/elast... Recent damages to the box-like structures caused by wave slamming have made it necessary to study the impact problems of this kind of structure. This paper showed findings from numerical simulations of the rigid/elastic structures, aiming to gain insights into the characteristics of the problem. The results of the rigid cases showed the significance of air compressibility during the impact process, while the slamming phenomena became quite different without the effect. In the elastic cases, the trapped air made the structure vibrate at frequencies much smaller than its eigenfrequencies. Besides, the structural deformation made it easy for the trapped air to escape outwards, which weakened the air cushioning effect, especially at high impact velocities. The above analysis gives the results when the structural symmetry axis was vertical to the water(vertical impacts). In addition, the results were given when the axis was oblique to the water(oblique impacts). Compared with the vertical cases, the impact phenomena and structural response showed asymmetry. This work used the computational fluid dynamics(CFD) method to describe fluid motion and the finite element method(FEM) for the deformable structure. A two-way coupling approach was used to deal with the fluid-structure interaction in the elastic cases. 展开更多
关键词 water impact fluid-structure interaction air compressibility box-like structures two-way coupling
下载PDF
Stable single longitudinal mode erbium-doped silica fiber laser based on an asymmetric linear three-cavity structure 被引量:2
4
作者 冯亭 延凤平 +4 位作者 李琦 彭万敬 冯素春 谭思宇 温晓东 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第1期268-272,共5页
We present a stable linear-cavity single longitudinal mode (SLM) erbium-doped silica fiber laser. It consists of four fiber Bragg gratings (FBGs) directly written in a section of photosensitive erbium-doped fiber ... We present a stable linear-cavity single longitudinal mode (SLM) erbium-doped silica fiber laser. It consists of four fiber Bragg gratings (FBGs) directly written in a section of photosensitive erbium-doped fiber (EDF) to form an asymmetric three-cavity structure. The stable SLM operation at a wavelength of 1545.112 nm with a 3-dB bandwidth of 0.012 nm and an optical signal-to-noise ratio (OSNR) of about 60 dB is verified experimentally. Under laboratory conditions, the performance of a power fluctuation of less than 0.05 dB observed from the power meter for 6 h and a wavelength variation of less than 0.01 nm obtained from the optical spectrum analyzer (OSA) for about 1.5 h are demonstrated. The gain fiber length is no longer limited to only several centimeters for SLM operation because of the excellent mode-selecting ability of the asymmetric three-cavity structure. The proposed scheme provides a simple and cost-effective approach to realizing a stable SLM fiber laser. 展开更多
关键词 asymmetric three-cavity structure single longitudinal mode erbium-doped fiber laser linear cavity
下载PDF
Numerical Simulation Study of Vibration Characteristics of Cantilever Traffic Signal Support Structure under Wind Environment
5
作者 Meng Zhang Zhichao Zhou +1 位作者 Guifeng Zhao Fangfang Wang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第1期673-698,共26页
Computational fluid dynamics(CFD)and the finite element method(FEM)are used to investigate the wind-driven dynamic response of cantilever traffic signal support structures as a whole.By building a finite element model... Computational fluid dynamics(CFD)and the finite element method(FEM)are used to investigate the wind-driven dynamic response of cantilever traffic signal support structures as a whole.By building a finite element model with the same scale as the actual structure and performing modal analysis,a preliminary understanding of the dynamic properties of the structure is obtained.Based on the two-way fluid-structure coupling calculation method,the wind vibration response of the structure under different incoming flow conditions is calculated,and the vibration characteristics of the structure are analyzed through the displacement time course data of the structure in the crosswind direction and along-wind direction.The results show that the maximum response of the structure increases gradually with the increase of wind speed under 90°wind direction angle,showing a vibration dispersion state,and the vibration response characteristics are following the vibration phenomenon of galloping;under 270°wind direction angle,the maximum displacement response of the structure occurs at the lower wind speed of 5 and 6m/s,and the vibration generated by the structure is vortex vibration at this time;the displacement response of the structure in along-wind direction increaseswith the increase of wind speed.The along-wind displacement response of the structure will increase with increasing wind speed,and the effective wind area and shape characteristics of the structurewill also affect the vibration response of the structure. 展开更多
关键词 Signal structure modal analysis wind-induced vibration two-way fluid-structure interaction numerical simulation
下载PDF
Structured illumination microscopy based on asymmetric three-beam interference 被引量:3
6
作者 Linyu Xu Yanwei Zhang +4 位作者 Song Lang Hongwei Wang Huijie Hu Jingkai Wang Yan Gong 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2021年第2期40-50,共11页
Structured illumination microscopy(SIM)is a rapidly developing super-resolution technology.It has been widely used in various application fields of biomedicine due to its excellent two-and three-dimensional imaging ca... Structured illumination microscopy(SIM)is a rapidly developing super-resolution technology.It has been widely used in various application fields of biomedicine due to its excellent two-and three-dimensional imaging capabilities.Furthermore,faster three-dimensional imaging methods are required to help enable more research-oriented living cell imaging.In this paper,a fast and sensitive three-dimensional structured illumination microscopy based on asymmetric three-beam interference is proposed.An innovative time-series acquisition method is employed to halve the time required to obtain each raw image.A segmented half-wave plate as a substantial linear polarization modulation method is applied to the three-dimensional SIM system for the first time.Although it needs to acquire 21 raw images instead of 15 to reconstruct one super-resolution image,the SIM setup proposed in this paper is 30%faster than the traditional spatial light modulator-SIM(SLM-SIM)in imaging each super-resolution image.The related theoretical derivation,hardware system,and verification experiment are elaborated in this paper.The stable and fast 3D super-resolution imaging method proposed in this paper is of great significance to the research of organelle interaction,intercellular communication,and other biomedical fields. 展开更多
关键词 SUPER-RESOLUTION structured illumination asymmetric three-beam interference three-dimensional imaging
下载PDF
Bcklund Transformation and Localized Coherent Structure for the (2+1)-Dimensional Asymmetric Nizhnik-Novikov-Veselov Equation 被引量:1
7
作者 张解放 刘宇陆 《Journal of Shanghai University(English Edition)》 CAS 2002年第3期191-195,共5页
This article is concerned with the extended homogeneous balance method for studying the abundant localized solution structure of the (2+1) dimensional asymmetric Nizhnik Novikov Veselov equation. A B a¨... This article is concerned with the extended homogeneous balance method for studying the abundant localized solution structure of the (2+1) dimensional asymmetric Nizhnik Novikov Veselov equation. A B a¨ cklund transformation was first obtained, and then the richness of the localized coherent structures was found, which was caused by the entrance of two variable separated arbitrary functions, in the model. For some special choices of the arbitrary functions, it is shown that the localized structures of the model may be dromions, lumps, and ring solitons. 展开更多
关键词 homogeneous balance method coherent soliton structures asymmetric Nizhnik Novikov veselov equation (ANNV equation) B cklund transformation.
下载PDF
Seismic Responses of Asymmetric Base-Isolated Structures under Near-Fault Ground Motion 被引量:1
8
作者 叶昆 李黎 方秦汉 《Journal of Southwest Jiaotong University(English Edition)》 2008年第4期335-345,共11页
An inter-story shear model of asymmetric base-isolated structures incorporating deformation of each isolation bearing was built, and a method to simultaneously simulate bi-directional near-fault and far-field ground m... An inter-story shear model of asymmetric base-isolated structures incorporating deformation of each isolation bearing was built, and a method to simultaneously simulate bi-directional near-fault and far-field ground motions was proposed. A comparative study on the dynamic responses of asymmetric base-isolated structures under near-fault and far-field ground motions were conducted to investigate the effects of eccentricity in the isolation system and in the superstructures, the ratio of the uncoupled torsional to lateral frequency of the superstructure and the pulse period of near-fault ground motions on the nonlinear seismic response of asymmetric base-isolated structures. Numerical results show that eccentricity in the isolation system makes asymmetric base-isolated structure more sensitive to near-fault ground motions, and the pulse period of near-fault ground motions plays an import role in governing the seismic responses of asymmetric base-isolated structures. 展开更多
关键词 asymmetric base-isolated structure Near-fault ground motion Far-field ground motion Nonlinear seismic response
下载PDF
Unidirectional transport of both wettable and nonwettable liquids on an asymmetrically concave structured surface
9
作者 Zhongxue Tang Kang Luan +1 位作者 Bojie Xu Huan Liu 《Fundamental Research》 CAS CSCD 2024年第3期557-562,共6页
Unidirectional liquid transport(UDLT)has been widely used in various fields as an important process for transferring both mass and energy.However,UDLT driven by a structural gradient has been witnessed for a long time... Unidirectional liquid transport(UDLT)has been widely used in various fields as an important process for transferring both mass and energy.However,UDLT driven by a structural gradient has been witnessed for a long time only in wettable liquids.For nonwettable liquids,UDLT can hardly proceed merely by a structural gradient.Herein,we propose an asymmetrically concave structured surface(AMC-surface),featuring tip-to-base periodically arranged pyramid-shaped concave structures with a certain degree of overlap,which enables the UDLT of both wettable and nonwettable liquids.For wettable liquids,the capillary force along each corner leads to the UDLT pointing toward the base side of the concave pyramid,while for nonwettable liquids,the UDLT is attributable to the static liquid pressure overwhelming the repulsive Laplace pressure induced by the asymmetric grooves and overlapping part.As a result,both wettable and nonwettable liquids transport spontaneously and unidirectionally on the AMC-surface with no energy input.Moreover,the concave structure endows good mechanical stability and can be easily prepared using a facile nail-punching approach over a large area.We also demonstrated its application in a continuous chemical reaction in a confined area.We envision that the unique UDLT behavior on the as-developed AMC-surface will shed new light on the programmable manipulation of various liquids. 展开更多
关键词 Unidirectional liquidtransport asymmetrically concave structure Capillary force Laplace pressure WETTABILITY
原文传递
12.6μm-Thick Asymmetric Composite Electrolyte with Superior Interfacial Stability for Solid-State Lithium-Metal Batteries
10
作者 Zheng Zhang Jingren Gou +4 位作者 Kaixuan Cui Xin Zhang Yujian Yao Suqing Wang Haihui Wang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第9期397-409,共13页
Solid-state lithium metal batteries(SSLMBs)show great promise in terms of high-energy-density and high-safety performance.However,there is an urgent need to address the compatibility of electrolytes with high-voltage ... Solid-state lithium metal batteries(SSLMBs)show great promise in terms of high-energy-density and high-safety performance.However,there is an urgent need to address the compatibility of electrolytes with high-voltage cathodes/Li anodes,and to minimize the electrolyte thickness to achieve highenergy-density of SSLMBs.Herein,we develop an ultrathin(12.6μm)asymmetric composite solid-state electrolyte with ultralight areal density(1.69 mg cm^(−2))for SSLMBs.The electrolyte combining a garnet(LLZO)layer and a metal organic framework(MOF)layer,which are fabricated on both sides of the polyethylene(PE)separator separately by tape casting.The PE separator endows the electrolyte with flexibility and excellent mechanical properties.The LLZO layer on the cathode side ensures high chemical stability at high voltage.The MOF layer on the anode side achieves a stable electric field and uniform Li flux,thus promoting uniform Li^(+)deposition.Thanks to the well-designed structure,the Li symmetric battery exhibits an ultralong cycle life(5000 h),and high-voltage SSLMBs achieve stable cycle performance.The assembled pouch cells provided a gravimetric/volume energy density of 344.0 Wh kg^(−1)/773.1 Wh L^(−1).This simple operation allows for large-scale preparation,and the design concept of ultrathin asymmetric structure also reveals the future development direction of SSLMBs. 展开更多
关键词 Solid-state lithium metal batteries Composite solid-state electrolyte Ultrathin asymmetric structure Pouch cells
下载PDF
Asymmetric structure of atomic above-threshold ionization spectrum in two-color elliptically polarized laser fields
11
作者 Xu-Cong Zhou Shang Shi +4 位作者 Fei Li Yu-Jun Yang Jing Chen Qing-Tian Meng Bing-Bing Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第10期183-191,共9页
According to the frequency-domain theory, we investigate the asymmetric structure of above-threshold ionization(ATI) spectrum of an atom in two-color elliptically polarized(EP) laser fields. When both laser fields are... According to the frequency-domain theory, we investigate the asymmetric structure of above-threshold ionization(ATI) spectrum of an atom in two-color elliptically polarized(EP) laser fields. When both laser fields are linearly polarized(LP), the spectrum shows that the multi-plateau structure is symmetric about the emitted angle of electron at π/2, while the spectrum becomes asymmetric and shifts rightwards with the increase of the EP degree of the IR laser field. Since the total ATI process is regarded as including direct ATI and the rescattering ATI, we analyze the spectrum structure of direct ATI and rescattering ATI separately. Using the saddle-point approximation, we find that for direct ATI, the fringes on the spectrum are mainly attributed to the fact that the ionization probability becomes very small when the direction of emitted electrons is perpendicular to the direction of the XUV laser polarization;while for the rescattering ATI, the interference fringes on the spectrum mainly come from the superposition of the waist structures on the spectra of all sub-channels. 展开更多
关键词 ABOVE-THRESHOLD IONIZATION elliptically POLARIZED two color laser FIELDS asymmetrIC structure
下载PDF
NUMERICAL EXPERIMENTS OF THE INFLUENCE OF DIABATIC HEATING ON TROPICAL CYCLONE ASYMMETRIC STRUCTURE
12
作者 雷小途 《Journal of Tropical Meteorology》 SCIE 1998年第2期131-140,共10页
Using the barotropic volticity equation that contains forcing from diabatic heating with appropriate parameterization. a number of numerical experiments are conducted for the tropical cyclone that is initially symmetr... Using the barotropic volticity equation that contains forcing from diabatic heating with appropriate parameterization. a number of numerical experiments are conducted for the tropical cyclone that is initially symmetric The result shows that the diabatic heating has important effects on the asymmetric structure in addition to the roll of the β term and nonlinear advection term in its formation. It again confirms the conclusion that the diabatic heating is a possible mechanism responsible for such structures in the tropical cyclone. 展开更多
关键词 TROPICAL CYCLONE asymmetrIC structure diabatic HEATING
下载PDF
A Single-Board Integrated Millimeter-Wave Asymmetric Full-Digital Beamforming Array for B5G/6G Applications
13
作者 Qingqing Lin Jun Xu +9 位作者 Kai Chen Long Wang Wei Li Zhiqiang Yu Guangqi Yang Jianyi Zhou Zhe Chen Jixin Chen Xiaowei Zhu Wei Hong 《Engineering》 SCIE EI CAS CSCD 2024年第10期35-50,共16页
In this article,a single-board integrated millimeter-wave(mm-Wave)asymmetric full-digital beamforming(AFDBF)array is developed for beyond-fifth-generation(B5G)and sixth-generation(6G)communications.The proposed integr... In this article,a single-board integrated millimeter-wave(mm-Wave)asymmetric full-digital beamforming(AFDBF)array is developed for beyond-fifth-generation(B5G)and sixth-generation(6G)communications.The proposed integrated array effectively addresses the challenge of arranging a large number of ports in a full-digital array by designing vertical connections in a three-dimensional space and successfully integrating full-digital transmitting(Tx)and receiving(Rx)arrays independently in a single board.Unlike the traditional symmetric array,the proposed asymmetric array is composed of an 8×8 Tx array arranged in a square shape and an 8+8 Rx array arranged in an L shape.The center-to-center distance between two adjacent elements is 0.54k0 for both the Tx and Rx arrays,where k0 is the free-space wavelength at 27 GHz.The proposed AFDBF array possesses a more compact structure and lower system hardware cost and power consumption compared with conventional brick-type full-digital arrays.In addition,the energy efficiency of the proposed AFDBF array outperforms that of a hybrid beamforming array.The measurement results indicate that the operating frequency band of the proposed array is 24.25–29.50 GHz.An eight-element linear array within the Tx array can achieve a scanning angle ranging from-47°to+47°in both the azimuth and the elevation planes,and the measured scanning range of each eight-element Rx array is–45°to+45°.The measured maximum effective isotropic radiated power(EIRP)of the eight-element Tx array is 43.2 dBm at 28.0 GHz(considering the saturation point).Furthermore,the measured error vector magnitude(EVM)is less than 3%when 64-quadrature amplitude modulation(QAM)waveforms are used. 展开更多
关键词 Full-digital beamforming array asymmetric structure Single-board integrated Beyond fifth-generation and sixthgeneration Millimeter-wave communication Complex modulation Printed circuit board Vertical connection
下载PDF
A NUMERICAL ANALYSIS ON TYPHOON ASYMMETRIC STRUCTUREAND MOTION
14
作者 袁金南 王国民 《Journal of Tropical Meteorology》 SCIE 1997年第2期159-167,共9页
Five prediction experiments are carried out with two typhoons in 1992 using a limited -arca primitiveequations and two-way interactive model in a movable ,nested mesh. The result indicates good agreementin terms of mo... Five prediction experiments are carried out with two typhoons in 1992 using a limited -arca primitiveequations and two-way interactive model in a movable ,nested mesh. The result indicates good agreementin terms of motion between the prediction and observation. Studying the asymmetric structure in the cas-es selected, a close link is uncovered between the temporal evolutions of the structure and the track of motion in a tropical cyclone. Understanding of real asymmetric structure will help to improve the skill offorecasting tropical cyclones. 展开更多
关键词 TYPHOON asymmetrIC structure TYPHOON TRACK of MOTION nested MESH model
下载PDF
Effect of the asymmetric geometry on the wake structures of a pitching foil
15
作者 LiMing Chao Guang Pan Dong Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第11期289-293,共5页
The two-dimensional wake produced by a time-periodic pitching foil with the asymmetric geometry is investigated in the present work. Through numerically solving nonlinear Navier–Stokes equations, we discuss the relat... The two-dimensional wake produced by a time-periodic pitching foil with the asymmetric geometry is investigated in the present work. Through numerically solving nonlinear Navier–Stokes equations, we discuss the relationship among the kinematics of the prescribed motion, the asymmetric parameter K ranged as-1 ≤ K ≤ 1, and the types of the wakes including the mP+nS wake, the B′enard–von K′arm′an wake, the reverse B′enard–von K′arm′an wake, and the deviated wake.Compared with previous studies, we reveal that the asymmetric geometry of a pitching foil directly affects the foil's wake structures. The numerical results show that the reverse B′enard–von K′arm′an wake is easily deviated at K 〈 0, while the symmetry-breaking of the reverse B′enard–von K′arm′an wake is delayed at K 〉 0. Through the vortex dynamic method,we understand that the initial velocity of the vortex affected by the foil's asymmetry plays a key role in the deviation of the reverse B′enard–von K′arm′an wake. Moreover, we provide a theoretical model to predict the wake deviation of the asymmetric foil. 展开更多
关键词 wake structures asymmetric geometry pitching foil
下载PDF
Synthesis and Crystal Structure of (R)-4-Hydroxymethyl-2-thioxo Thiazolidine and Its Asymmetric Catalysis
16
作者 LI Jing SHANG Yan-mei +3 位作者 XIAO Chuan SONG Zhi-guang LI Ye-zhi HUANG Hua-min 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2009年第1期43-46,共4页
(R)-4-Hydroxymethyl-2-thioxo thiazolidine as a new chiral catalyst in the asymmetric addition of diethylzinc to benzaldehyde was synthesized from (R)-4-hydroxymethyl-2-thioxo thiazolidine carboxylic acid and its c... (R)-4-Hydroxymethyl-2-thioxo thiazolidine as a new chiral catalyst in the asymmetric addition of diethylzinc to benzaldehyde was synthesized from (R)-4-hydroxymethyl-2-thioxo thiazolidine carboxylic acid and its crystal structure was determined by X-ray diffraction method. The compound was crystallized in the orthorhombic system, space group P212121 with unit cell dimensions a=0.67253(12) nm; b=0.89164(17) nm; c=1.06146(19) nm, volume 0.6365(2) nm^3; Z=4, calculated denisity 1.557 Mg/m^3; absorption coefficient 0.733 mm^-1; F(000)=312. The X-ray crystal structure analysis reveals that the compound has a thione group. 展开更多
关键词 Crystal structure asymmetrIC (R)-4-Hydroxymethyl-2-thioxothiazolidine
下载PDF
The role of viscoelastic damping on retrofitting seismic performance of asymmetric reinforced concrete structures
17
作者 Zeshan Alam Chunwei Zhang Bijan Samali 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2020年第1期223-237,共15页
The primary purpose of this research is to improve the seismic response of a complex asymmetric tall structure using viscoelastic(VE) dampers. Asymmetric structures have detrimental effects on the seismic performance ... The primary purpose of this research is to improve the seismic response of a complex asymmetric tall structure using viscoelastic(VE) dampers. Asymmetric structures have detrimental effects on the seismic performance because such structures create abrupt changes in the stiffness or strength that may lead to undesirable stress concentrations at weak locations. Structural control devices are one of the effective ways to reduce seismic impacts, particularly in asymmetric structures. For passive vibration control of structures, VE dampers are considered among the most preferred devices for energy dissipation. Therefore, in this research, VE dampers are implemented at strategic locations in a realistic case study structure to increase the level of distributed damping without occupying significant architectural space and reducing earthquake vibrations in terms of story displacements(drifts) and other design forces. It has been concluded that the seismic response of the considered structure retrofitted with supplemental VE dampers corresponded well in controlling the displacement demands. Moreover, it has been demonstrated that seismic response in terms of interstory drifts was effectively mitigated with supplemental damping when added up to a certain level. Exceeding the supplemental damping from this level did not contribute to additional mitigation of the seismic response of the considered structure. In addition, it was found that the supplemental damping increased the total acceleration of the considered structure at all floor levels, which indicates that for irregular tall structures of this type, VE dampers were only a good retrofitting measure for earthquake induced interstory deformations and their use may not be suitable for acceleration sensitive structures. Overall, the research findings demonstrate how seismic hazards to these types of structures can be reduced by introducing additional damping into the structure. 展开更多
关键词 viscoelastic dampers seismic analysis asymmetric structure nonlinear modal time history analysis
下载PDF
SYNTHESIS AND STRUCTURE OF AN ASYMMETRIC TRICOBALT COMPOUND Co_3(o-HOC_6H_4S)_2(o-OC_6H_4S)_2(PEt_3)_3
18
作者 Yong Jin XU Bei Sheng KANG Xue Tai CHEN Yong Han HU Fujian Institute of Research on the Structure of Matter and Fuzhou Laboratory of Structural Chemistry Chinese Academy of Science,Fuzhou,Fujian 350002 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第12期1017-1018,共2页
Compound Co_3(o-HOC_6H_4S)_2(o-OC_6H_4S)_2(PEt_3)_3 was obtained by reaction of CoCl_2, o-HOC_6H_4SH(H_2mD)and PEt_3 in ethanol in the presence of NaOCH_3.The three Co atoms are triangularly arranged and asymmetricall... Compound Co_3(o-HOC_6H_4S)_2(o-OC_6H_4S)_2(PEt_3)_3 was obtained by reaction of CoCl_2, o-HOC_6H_4SH(H_2mD)and PEt_3 in ethanol in the presence of NaOCH_3.The three Co atoms are triangularly arranged and asymmetrically bridged by four S and one O atoms from the four H_2mp ligands and terminally ligated by one O and three P atoms.Two free hydroxyl groups form two internal hydrogen bonds with adjacent oxo donor atoms. 展开更多
关键词 Co PEt3 SYNTHESIS AND structure OF AN asymmetrIC TRICOBALT COMPOUND Co3 o-HOC6H4S o-OC6H4S OC
下载PDF
Interaction Between Large-scale Vortex Structure and Dispersed Particles in a Three Dimensional Mixing Layer 被引量:4
19
作者 罗坤 郑友取 +1 位作者 樊建人 岑可法 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第4期377-382,共6页
In order to understand the interaction between large-scale vortex structure and particles, a two-way coupling temporal mixing layer laden with particles at a Stokes number of 5 with different mass loading planted init... In order to understand the interaction between large-scale vortex structure and particles, a two-way coupling temporal mixing layer laden with particles at a Stokes number of 5 with different mass loading planted initially in the upper half region is numerically studied. The pseudospectral method is used for the flow fluid and the Lagrangian approach is employed to trace particles. The momentum coupling effect introduced by a particle is approximated to a point force. The simulation results show that the coherent structures are still dominant in the mixing layer, but the large-scale vortex structure and particle dispersion are modulated. The length of large-scale vortex structure is shortened and the pairing is delayed. At the same time, the particles are distributed more evenly in the whole flow field as the mass loading is increased, but the particle dispersion along the transverse direction differs from that along the spanwise direction, which indicates that the effect by the addition of particle on the spanwise large-scale vortex structure is different from the streamwise counterpart. 展开更多
关键词 INTERACTION MODULATION two-way coupling large-scale vortex structures particle dispersion
下载PDF
Performance of Physical-Layer Network Coding in Asymmetric Two-Way Relay Channels 被引量:3
20
作者 李博 王钢 +3 位作者 Peter H.J.Chong 杨洪娟 Yongliang GUAN 沙学军 《China Communications》 SCIE CSCD 2013年第10期65-73,共9页
In this paper, we study the performance of physical-layer network coding in asymmetric two-way relay channels using four different cases having different poor channels:phase asymmetry, downlink asymmetry, uplink asymm... In this paper, we study the performance of physical-layer network coding in asymmetric two-way relay channels using four different cases having different poor channels:phase asymmetry, downlink asymmetry, uplink asymmetry and node asymmetry. The decision and mapping rule for symmetric and asymmetric cases are studied. The performance in terms of bit error rate for each case will be studied and analysed by computer simulation. Analytical and simulation results show that uplink asymmetry is the worst case;intra-phase asymmetry and unreliable uplink channels will more severely affect the performance degradation, which is caused by channel asymmetry. 展开更多
关键词 physical-layer network coding two-way relay channels asymmetric channels bit error rate
下载PDF
上一页 1 2 41 下一页 到第
使用帮助 返回顶部