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Relationship between polyhedral structures formed by tangent planes of ellipsoidal particles and system sound velocity
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作者 Cheng-Bo Li Lin Bao Chuang Zhao 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第11期448-456,共9页
Internal polyhedral structures of a granular system can be investigated using the Voronoi tessellations.This technique has gained increasing recognition in research of kinetic properties of granular flows.For systems ... Internal polyhedral structures of a granular system can be investigated using the Voronoi tessellations.This technique has gained increasing recognition in research of kinetic properties of granular flows.For systems with mono-sized spherical particles,Voronoi tessellations can be utilized,while radial Voronoi tessellations are necessary for analyzing systems with multi-sized spherical particles.However,research about polyhedral structures of non-spherical particle systems is limited.We utilize the discrete element method to simulate a system of ellipsoidal particles,defined by the equation(x a)2+(y1)2+(z 1/a)2=1,where a ranges from 1.1 to 2.0.The system is then dissected by using tangent planes at the contact points,and the geometric quantities of the resulting polyhedra in different shaped systems,such as surface area,volume,number of vertices,number of edges,and number of faces,are calculated.Meanwhile,the longitudinal and transverse wave velocities within the system are calculated with the time-of-flight method.The results demonstrate a strong correlation between the sound velocity of the system and the geometry of the dissected polyhedra.The sound velocity of the system increases with the increase in a,peaking at a=1.3,and then decreases as a continues to increase.The average volume,surface area,number of vertices,number of edges,and number of faces of the polyhedra decrease with the increase in sound velocity.That is,these quantities initially decrease with the increase in a,reaching minima at a=1.3,and then increase with further increase of a.The relationship between sound velocity and the geometric quantities of the dissected polyhedra can serve as a reference for acoustic material design. 展开更多
关键词 discrete element method Voronoi tessellation polyhedral structure sound velocity
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Research on Volume Identification with the Method of Discharging at the Velocity of Sound
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作者 范伟 彭光正 王涛 《Journal of Beijing Institute of Technology》 EI CAS 2002年第1期1-4,共4页
The method of volume identification in pneumatics was studied through theoretical analysis and experimental investigation. Regarding discharging from a container as a thermodynamic process with invariable index the d... The method of volume identification in pneumatics was studied through theoretical analysis and experimental investigation. Regarding discharging from a container as a thermodynamic process with invariable index the dependence of the container’s volume on the pressure in the container and the index, during discharging at the velocity of sound, is deduced. Then through a lot of experiments, the value of index n of the process is found with a given precision and a specified volume range. Furthermore, the feasibility and practicability of this method are verified by experiments. 展开更多
关键词 volume identification discharging at the velocity of sound thermodynamic process leakage detecting
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Influence of Microstructure Change of Seafloor Sediments on the Sound Velocity in them in the Course of Stress-strain
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作者 李赶先 卢博 黄韶健 《Marine Science Bulletin》 CAS 2009年第1期62-69,共8页
Test tools and methods for synchronizing acoustic measurements in the course of stress-strain for seafloor sediment are elaborated and the test data of 45 sediment samples from the seafloor in the South China Sea are ... Test tools and methods for synchronizing acoustic measurements in the course of stress-strain for seafloor sediment are elaborated and the test data of 45 sediment samples from the seafloor in the South China Sea are analysed. The result shows that the coarser the sediment grains are, the smaller the porosity is and the larger the unconfined compression strength is, the higher the sound velocity is. In the course of stress-strain, the sediment sound velocity varies obviously with the stress. Acoustic characteristics of sediment in different strain phases and the influence of sediment microstructure change on its sound velocity are discussed. This study will be of important significance for surveying wells of petroleum geology and evaluating the base stabilization of seafloor engineering. 展开更多
关键词 seafloor sediment STRESS-STRAIN microstructure features sound velocity compression strength
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Sound velocity and related properties of seafloor sediments in the Bering Sea and Chukchi Sea 被引量:5
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作者 MENG Xiangmei LI Guanbao +1 位作者 HAN Guozhong KAN Guangming 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第5期75-80,共6页
The Bering Sea shelf and Chukchi Sea shelf are believed to hold enormous oil and gas reserves which have attracted a lot of geophysical surveys. For the interpretation of acoustic geophysical survey results, sediment ... The Bering Sea shelf and Chukchi Sea shelf are believed to hold enormous oil and gas reserves which have attracted a lot of geophysical surveys. For the interpretation of acoustic geophysical survey results, sediment sound velocity is one of the main parameters. On seven sediment cores collected from the Bering Sea and Chukchi Sea during the 5th Chinese National Arctic Research Expedition, sound velocity measurements were made at 35, 50, 100, 135, 150, 174, 200, and 250 kHz using eight separate pairs of ultrasonic transducers. The measured sound velocities range from 1 425.1 m/s to 1 606.4 m/s and are dispersive with the degrees of dispersion from 2.2% to 4.0% over a frequency range of 35-250 kHz. After the sound velocity measurements, the measurements of selected geotechnical properties and the Scanning Electron Microscopic observation of microstructure were also made on the sediment cores. The results show that the seafioor sediments are composed of silty sand, sandy silt, coarse silt, clayey silt, sand-silt-clay and silty clay. Aggregate and diatom debris is found in the seafloor sediments. Through comparative analysis of microphotographs and geotechnical properties, it is assumed that the large pore spaces between aggregates and the intraparticulate porosity of diatom debris increase the porosity of the seafioor sediments, and affect other geotechnical properties. The correlation analysis of sound velocity and geotechnical properties shows that the correlation of sound velocity with porosity and wet bulk density is extreme significant, while the correlation of sound velocity with clay content, mean grain size and organic content is not significant. The regression equations between porosity, wet bulk density and sound velocity based on best-fit polynomial are given. 展开更多
关键词 Bering Sea Chukchi Sea sound velocity geotechnical properties MICROSTRUCTURE
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ST-LSTM-SA:A New Ocean Sound Velocity Field Prediction Model Based on Deep Learning 被引量:1
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作者 Hanxiao YUAN Yang LIU +3 位作者 Qiuhua TANG Jie LI Guanxu CHEN Wuxu CAI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第7期1364-1378,共15页
The scarcity of in-situ ocean observations poses a challenge for real-time information acquisition in the ocean.Among the crucial hydroacoustic environmental parameters,ocean sound velocity exhibits significant spatia... The scarcity of in-situ ocean observations poses a challenge for real-time information acquisition in the ocean.Among the crucial hydroacoustic environmental parameters,ocean sound velocity exhibits significant spatial and temporal variability and it is highly relevant to oceanic research.In this study,we propose a new data-driven approach,leveraging deep learning techniques,for the prediction of sound velocity fields(SVFs).Our novel spatiotemporal prediction model,STLSTM-SA,combines Spatiotemporal Long Short-Term Memory(ST-LSTM) with a self-attention mechanism to enable accurate and real-time prediction of SVFs.To circumvent the limited amount of observational data,we employ transfer learning by first training the model using reanalysis datasets,followed by fine-tuning it using in-situ analysis data to obtain the final prediction model.By utilizing the historical 12-month SVFs as input,our model predicts the SVFs for the subsequent three months.We compare the performance of five models:Artificial Neural Networks(ANN),Long ShortTerm Memory(LSTM),Convolutional LSTM(ConvLSTM),ST-LSTM,and our proposed ST-LSTM-SA model in a test experiment spanning 2019 to 2022.Our results demonstrate that the ST-LSTM-SA model significantly improves the prediction accuracy and stability of sound velocity in both temporal and spatial dimensions.The ST-LSTM-SA model not only accurately predicts the ocean sound velocity field(SVF),but also provides valuable insights for spatiotemporal prediction of other oceanic environmental variables. 展开更多
关键词 sound velocity field spatiotemporal prediction deep learning self-allention
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Influence of Environmental Conditions on the Sound Velocity Ratio of Seafloor Surficial Sediment 被引量:3
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作者 ZOU Dapeng ZENG Ziwen +2 位作者 KAN Guangming LIU Wei XIAO Tibing 《Journal of Ocean University of China》 SCIE CAS CSCD 2021年第3期573-580,共8页
In this work,we investigated the influences of salinity,temperature,and hydrostatic pressure on the acoustics of seafloor surficial sediment by theoretically and experimentally analyzing the sound velocity ratio of th... In this work,we investigated the influences of salinity,temperature,and hydrostatic pressure on the acoustics of seafloor surficial sediment by theoretically and experimentally analyzing the sound velocity ratio of the seafloor sediment to the bottom sea-water in typical environmental conditions.Temperature-and pressure-controlled experiments were conducted to examine the charac-teristics of the sound velocity ratio,the results of which agree with the theoretical analysis using the effective density fluid model.Of the three environmental factors considered,the sound velocity ratio was found to be sensitive to temperature and pressure but not to salinity,with the sound velocity ratio decreasing with temperature and hydrostatic pressure.With respect to surficial sediments,pore water plays a key role in the sound velocity ratio of sediment influenced by different environmental factors.The sound velocities of different types of sediments(sandy,silty,and clayey)change similarly with temperature,but change slightly differently with hydro-static pressure.The influence of environmental factors on the sound velocity ratio of seafloor sediment is independent of the detec-tion frequency.The results show that the sound velocity ratio can change up to 0.0008 per℃ when the temperature ranges from 2℃ to 25℃ and up to 0.00064MPa−1 when the seawater depth pressure ranges from 0MPa to 40MPa. 展开更多
关键词 sound velocity ratio environmental factors SEAFLOOR SEDIMENT geoacoustics
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The sound velocity and bulk properties of sediments in the Bohai Sea and the Yellow Sea of China 被引量:2
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作者 ZHENG Jiewen LIU Baohua +3 位作者 KAN guangming LI Guanbao PEI Yanliang LIU Xiaolei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第7期76-86,共11页
In order to investigate the correlation between a sound velocity and sediment bulk properties and explore the influence of frequency dependence of the sound velocity on the prediction of the sediment properties by the... In order to investigate the correlation between a sound velocity and sediment bulk properties and explore the influence of frequency dependence of the sound velocity on the prediction of the sediment properties by the sound velocity, a compressional wave velocity is measured at frequencies of 25-250 kHz on marine sediment samples collected from the Bohai Sea and the Yellow Sea in laboratory, together with the geotechnical parameters of sediments. The results indicate that the sound velocity ranges from 1.232 to 1.721 km/s for the collected sediment samples with a significant dispersion within the series measuring frequency. Poorly sorted sediments are highly dispersive nearly with a positive linear relationship. The porosity shows a better negative logarithmic correlation with the sound velocity compared with other geotechnical parameters. Generally, the sound velocity increases with the increasing of the average particle size, sand content, wet and dry bulk densities, and decreasing of the clay content, and water content. An important point should be demonstrated that the higher correlation can be obtained when the measuring frequency is low within the frequency ranges from 25 to 250 kHz since the inhomogeneity of sediment properties has a more remarkably influence on the laboratory sound velocity measurement at the high frequency. 展开更多
关键词 sound velocity particle composition physical properties frequency dispersion empirical equation
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Relationships of the internodal distance of biological tissue with its sound velocity and attenuation at high frequency in doublet mechanics
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作者 程凯旋 吴融融 +3 位作者 刘晓宙 刘杰惠 龚秀芬 吴君汝 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第4期257-261,共5页
In view of the discrete characteristics of biological tissue, doublet mechanics has demonstrated its advantages in the mathematic description of tissue in terms of high frequency (〉 10 MHz) ultrasound. In this pape... In view of the discrete characteristics of biological tissue, doublet mechanics has demonstrated its advantages in the mathematic description of tissue in terms of high frequency (〉 10 MHz) ultrasound. In this paper, we take human breast biopsies as an example to study the influence of the internodal distance, a microscope parameter in biological tissue in doublet mechanics, on the sound velocity and attenuation by numerical simulation. The internodal distance causes the sound velocity and attenuation in biological tissue to change with the increase of frequency. The magnitude of such a change in pathological tissue is distinctly different from that in normal tissue, which can be used to differentiate pathological tissue from normal tissue and can depict the diseased tissue structure by obtaining the sound and attenuation distribution in the sample at high ultrasound frequency. A comparison of sensitivity between the doublet model and conventional continuum model is made, indicating that this is a new method of characterizing ultrasound tissue and diagnosing diseases. 展开更多
关键词 doublet mechanics sound velocity sound attenuation ultrasound tissue characteristics
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Relationship between in situ sound velocity and granular characteristics of seafloor sediments in the Qingdao offshore region
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作者 张严心 郭常升 +2 位作者 王景强 侯正瑜 陈文景 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第3期704-711,共8页
The sound velocity of seafloor sediments from shallow seas can provide important information for harbor design, and ocean and seacoast engineering projects. In this study, in situ measurements were used to obtain accu... The sound velocity of seafloor sediments from shallow seas can provide important information for harbor design, and ocean and seacoast engineering projects. In this study, in situ measurements were used to obtain accurate sediment sound velocities at 45 stations offshore of Qingdao. The relationships between the sound velocity and granular properties of the seafloor sediments were analyzed. Sound velocity showed an increase with the sand content, sand-clay ratio, and sorting coefficient; and a nonlinear decreasing trend with increasing mean grain size and clay content. We plotted a sound velocity distribution map, which shows that the sound velocity was closely related to the geological environment. Previous empirical equations suggested by Hamilton, Anderson, and Liu were used to calculate the velocity with grain size. A comparison between the measured and calculated velocities indicates that the empirical equations have territorial limitations, and extensive data are essential to establish global empirical equations. Future work includes the calibration of the laboratory acoustic measurements with an in situ technique. 展开更多
关键词 sound velocity granular properties empirical equation
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Vertical Sound Velocity Transition in the Coral Reef Core and its Significance of Indicating Facies
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作者 李赶先 卢博 《Marine Science Bulletin》 CAS 2002年第1期19-26,共8页
On the basis of the sound velocity measurements of the coral reef core from Nanyong No. 1 Well of Yongshu Reef in the Nansha Islands, the paper studies the relations between the vertical sound velocity transition feat... On the basis of the sound velocity measurements of the coral reef core from Nanyong No. 1 Well of Yongshu Reef in the Nansha Islands, the paper studies the relations between the vertical sound velocity transition features in the coral reef core and the corresponding stratigraphic depositional facies change as well as stratigraphic gap of erosion, analyses the cause of the sound velocity transition, expounds the concrete process of the sea level change resulting in the stratigraphic gap of erosion and facies change in the coral reef and explains the relations between the vertical sound velocity transition in the coral reef core and the corresponding stratigraphic paleoclimate and the sea level change. This study is of important practical value and theoretical significance to the island and reef engineering construction and the acoustic logging for oil exploration in the reef limestone area as well as the paleoceanographic study of the marginal sea in the western Pacific Ocean. 展开更多
关键词 Coral reef sound velocity depositional facies sea level change
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Effect of Wood Waste on Acoustic and Magnetic Properties of Composite Bricks and Correlation between Sound Velocity and Magnetic Induction in These Bricks
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作者 Gilbert Ganga Adolphe Kimbonguila Manounou +2 位作者 Narcisse Malanda Michel Dzondo Gadet Timothée Nsongo 《Open Journal of Composite Materials》 2020年第1期15-25,共11页
In the present study, kambala (botanical name: Chlorophora excelsa and Chlorophora regia) wood wastes were incorporated into stabilized earth bricks in order to test their acoustic insulation capacity of the walls;lea... In the present study, kambala (botanical name: Chlorophora excelsa and Chlorophora regia) wood wastes were incorporated into stabilized earth bricks in order to test their acoustic insulation capacity of the walls;leading to better waste management from the timber industry. Two methods have been applied to determine the influence of the wood waste content in the stabilized earth bricks, on the weakening of the level of noise reception coming from the environmental medium, in an apartment built with composite bricks (earth + wood chips + cement). This influence has also been analyzed on the magnetic field induced by these bricks. The results showed that the level of sound reception through these bricks decreases with increasing wood waste content regardless of the method used (from 110 dB to 68 dB, respectively for Φb = 0% and Φb = 8%). The kambala wood waste in cement-stabilized clay bricks induces a magnetic field that increases with the wood waste content;the high contents of the wood chips causing an increase in the magnetic permeability of the composite medium. The correlation between the noise level and the magnetic field of the bricks shows that the noise level declines with increasing magnetic induction of the bricks. 展开更多
关键词 Kambala TREE WOOD Waste CLAY BRICK sound velocity MAGNETIC Field
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The universal sound velocity formula for the strongly interacting unitary Fermi gas 被引量:2
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作者 刘可 陈继胜 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第2期93-97,共5页
Due to the scale invariance, the thermodynamic laws of strongly interacting limit unitary Fermi gas can be similar to those of non-interacting ideal gas. For example, the virial theorem between pressure and energy den... Due to the scale invariance, the thermodynamic laws of strongly interacting limit unitary Fermi gas can be similar to those of non-interacting ideal gas. For example, the virial theorem between pressure and energy density of the ideal gas P = 2E/aV is still satisfied by the unitary Fermi gas. This paper analyses the sound velocity of unitary Fermi gases with the quasi-linear approximation. For comparison, the sound velocities for the ideal Boltzmann, Bose and Fermi gas are also given. Quite interestingly, the sound velocity formula for the ideal non-interacting gas is found to be satisfied by the unitary Fermi gas in different temperature regions. 展开更多
关键词 unitary Fermi gas sound velocity universal thermodynamics
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Inversion Method for Sound Velocity Profile of Eddy in Deep Ocean
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作者 邱晓芳 彭临慧 +1 位作者 王宁 朱建相 《China Ocean Engineering》 SCIE EI 2001年第4期589-596,共8页
The modal wave number tomography approach is used to obtain sound speed profile of water column in deep ocean. The approach consists of estimation of the local modal eigenvalues from complex pressure field and use of ... The modal wave number tomography approach is used to obtain sound speed profile of water column in deep ocean. The approach consists of estimation of the local modal eigenvalues from complex pressure field and use of these data as input to modal perturbative inversion method for obtaining the local sound speed profile. The empirical orthonormal function (EOF) is applied to reduce the parameter search space. The ocean environment used for numerical simulations includes the Munk profile as the unperturbed background speed profile and a weak Gaussian eddy as the sound speed profile perturbation. The results of numerical simulations show the method is capable of monitoring the oceanic interior structure. 展开更多
关键词 MODAL TOMOGRAPHY sound velocity profile inverse empirical orthonormal function
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Influences of Medium Structure of Three-Phase Seabed Deposit on Sound Velocity
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作者 徐长节 蔡袁强 《China Ocean Engineering》 SCIE EI 2001年第4期579-588,共10页
Based on the former research, the mechanism of the influence of the medium structure on the sound velocity of the three-phase seabed deposit is discussed by theoretical method. Through analysis of several structure mo... Based on the former research, the mechanism of the influence of the medium structure on the sound velocity of the three-phase seabed deposit is discussed by theoretical method. Through analysis of several structure models of three-phase seabed deposit, an equation of sound velocity is presented, which can describe the effect of structure of three-phase deposit on its acoustic velocity. Seen form the derived equation, the equations of the sound velocity of the deposits with different medium structures are different, the influence of the medium structure on the sound velocity is apparent. The equation in the paper provides the theoretical basis to understand the mechanics properties through sound velocity test, and it can be easily adopted in engineering. The influences of the parameters of deposits, void ratio, gas concentration and modulus on sound velocity through the deposit are investigated by numerical analysis of the acoustic velocity. Numerical result shows that the sound velocity of three-phase medium is affected by void ratio, gas concentration and body modulus, and the sound velocity generally increases with the gas concentration increasing. The results of the paper can be helpful to the acoustic method. 展开更多
关键词 three-phase seabed deposit medium structure sound velocity
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Three-Dimensional P-Wave Velocity Structure of the Crust of North China
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作者 魏文博 叶高峰 +3 位作者 李艳军 金胜 邓明 景建恩 《Journal of China University of Geosciences》 SCIE CSCD 2007年第3期257-268,共12页
Since the Xingtai (邢台) earthquake in 1966, China Earthquake Administration has carried out a survey campaign along more than thirty deep seismic sounding (DSS) profiles altogether about twenty thousand kilometer... Since the Xingtai (邢台) earthquake in 1966, China Earthquake Administration has carried out a survey campaign along more than thirty deep seismic sounding (DSS) profiles altogether about twenty thousand kilometers long in North China to study the velocity structure of the crust and the upper mantle in this region, and has obtained a great number of research findings. However, these researches have not provided a 3D velocity structure model of the crust of North China and cannot provide seismic evidence for the study of the deep tectonic characteristics of the crust of the whole region. Hence, based on the information from the published data of the DSS profiles, we have chosen 14 profiles to obtain a 3D velocity structure model of North China using the vectorization function of the GIS software (Arc/Info) and the Kriging data gridding method. With this velocity structure model, we have drawn the following conclusions: (1) The P-wave velocity of the uppermost crust of North China changes dramatically, exhibiting a complicated velocity structure in plane view. It can be divided into three velocity zones mainly trending towards north-west. In the research area, the lowest-velocity zones lie in the Haihe (海河) plain and Bohai (渤海) Bay. Although the geological structure of the sedimentary overburden in the study area is somewhat inherited by the upper crust, there are still several differences between them. (2) Generally, the P-wave velocity of the crust increases with depth in the study area, but there still exists local velocity reversion. In the east, low-velocity anomalies of the Haihe plain gradually disappear with increasing depth, and the Shanxi (山西) graben in the west is mainly characterized by relatively low velocity anomalies. Bounded by the Taihang (太行) Mountains, the eastern and western parts differ in structural trend of stratum above the crystalline basement. The structural trend of the Huanghuaihai (黄淮海) block in the east is mainly north-east, while that of the Shanxi block and the eastern edge of the Ordos block is mainly north-west. (3) According to the morphological features of Moho, the crust of the study area can be divided into six blocks. In the Shanxi block, Moho apppears like a nearly south-north trending depression belt with a large crustal thickness. In the southern edge of the Inner Mongolia block and the south of the Yanshan (燕山) block,the Moho exhibits a feature of fold belt, trending nearly towards east-west. In the eastern edge of the Ordos block, the structure of Moho is relatively complex, presenting a pattern of fold trending nearly towards north-west with alternating convexes and concaves. Beneath the Huanghuaihai block, the middle and northern parts of the North China rift zone, the Moho is the shallowest in the entire region, with alternating uplifts and depressions in its shape. For the anteclise zone in the west of Shandong (山东) Province, the Moho is discontinuous for the fault depression extending in the north-west direction along Zaozhuang (枣庄) -Qufu (曲阜). 展开更多
关键词 North China CRUST deep seismic sounding three-dimensional P-wave velocity structure
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A Method for the Removal of Ray Refraction Effects in Multibeam Echo Sounder Systems
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作者 DING Jisheng ZHOU Xinghua TANG Qiuhua 《Journal of Ocean University of China》 SCIE CAS 2008年第2期233-236,共4页
To a multibeam echo sounder system (MBES), under water sound refraction plays an important role in depth measure- ment accuracy, and errors in sound velocity profile lead to inaccuracies in the measured depth (especia... To a multibeam echo sounder system (MBES), under water sound refraction plays an important role in depth measure- ment accuracy, and errors in sound velocity profile lead to inaccuracies in the measured depth (especially for outer beams). A method is developed to estimate the sound velocity profile based on the depth measured by vertical beam. Using this depth and other pa- rameters, such as t (sound pulse propagation time), θ (beam inclination angle), etc. We can estimate a simple sound velocity profile with which the depth error has been reduced. This method has been tested with a real dataset acquired in the East China Sea. 展开更多
关键词 multibeam echo sounder system acoustic ray refraction equivalent sound velocity profile
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Ultrasonic Resonator Techniques for Broad-band Spectroscopy and for High-resolution Sound Velocity Measurement of Liquids
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作者 Udo Kaatze Frieder Eggers 《Journal of Measurement Science and Instrumentation》 CAS 2010年第1期1-9,共9页
This review gives a short introduction into the principles of ultrasonic measurement techniques for liquids, using cavity resonators. Guidelines for the resonator design in broad-band ultrasonic stxctroscopy as well a... This review gives a short introduction into the principles of ultrasonic measurement techniques for liquids, using cavity resonators. Guidelines for the resonator design in broad-band ultrasonic stxctroscopy as well as in high-resolution single-frequncy or narrowband applications are presented. Deviations of the field configuration in real cells frtxn that in an ideal resonator are discussed and relations for the mode spectrum of cavity fields are given. Recent resonator measurement procedures and methods of data evaluation are mentioned briefly. Some examples of measurements show the extended usability of ultrasonic resonator techniques in basic science and in a wide range of applications for rrkaterials characterization, in manufacturing processes, as well as in control routines. 展开更多
关键词 ultrasonic measurements liquids sound velocity attenuation coefficient resonator techniques ultrasonic spectrometry
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A geometric Model for the Spatial Correlation of an Acoustic Vector Field in Surface-generated Noise 被引量:4
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作者 Yiwang Huang (1) huangyiwang@hrbeu.edu.cn Qunyan Ren (12) Ting Li (3) 《Journal of Marine Science and Application》 2012年第1期119-125,共7页
Spatial correlation of sound pressure and particle velocity of the surface noise in horizontally stratified media was demonstrated, with directional noise sources uniformly distributed on the ocean surface. In the eva... Spatial correlation of sound pressure and particle velocity of the surface noise in horizontally stratified media was demonstrated, with directional noise sources uniformly distributed on the ocean surface. In the evaluation of particle velocity, plane wave approximation was applied to each incident ray. Due to the equivalence of the sound source correlation property and its directivity, solutions for the spatial correlation of the field were transformed into the integration of the coherent function generated by a single directional source. As a typical horizontally stratified media, surface noise in a perfect waveguide was investigated. Correlation coefficients given by normal mode and geometric models show satisfactory agreement. Also, the normalized covariance between sound pressure and the vertical component of particle velocity is proportional to acoustic absorption coefficient, while that of the surface noise in semi-infinitely homogeneous space is zero. 展开更多
关键词 spatial correlation sound pressure and particle velocity surthce noise stratitied media ray theory
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Pressure calibration and sound velocity measurement to 12 GPa in multi-anvil apparatus
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作者 Wei Song Shuangming Shan +2 位作者 Qizhe Tang Chang Su Yonggang Liu 《Acta Geochimica》 EI CAS CSCD 2021年第4期525-531,共7页
We performed the pressure calibration to 12 GPa for 14/6 type(octahedron edge length/WC truncated edge length,in mm) cell assembly in DS 6 × 1400 multi-anvil apparatus by using the phase transitions in Bi(Ⅰ-Ⅱ2.... We performed the pressure calibration to 12 GPa for 14/6 type(octahedron edge length/WC truncated edge length,in mm) cell assembly in DS 6 × 1400 multi-anvil apparatus by using the phase transitions in Bi(Ⅰ-Ⅱ2.55 GPa,Ⅲ-Ⅴ 7.67 GPa) and ZnTe(LPP-HPP Ⅰ 9.6 GPa,HPP Ⅰ-Ⅱ 12.0 GPa).As verification and application,sound velocity measurements on poly crystalline Al_(2)O_(3) to 12 GPa at room temperature were conducted and the ultrasonic result is in good agreement with previous reports.It demonstrates the feasibility of performing sound velocity measurements close to the mantle transition zone pressure condition in our laboratory. 展开更多
关键词 Pressure calibration sound velocity Multi-anvil apparatus Polycrystalline alumina
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Sound Velocity in Soap Foams
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作者 WU Gong-Tao LÜYong-Jun +2 位作者 LIU Peng-Fei LI Yi-Ning SHI Qing-Fan 《Chinese Physics Letters》 SCIE CAS CSCD 2012年第10期81-84,共4页
The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method.It is found that the sound velocities increase with increasing bubble diameter,and asympto... The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method.It is found that the sound velocities increase with increasing bubble diameter,and asymptotically approach to the value in air when the diameter is larger than 12.5 mm.We propose a simple theoretical model for the sound propagation in a disordered foam.In this model,the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional length.This simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the experiments.Further measurements indicate that the increase of frequency markedly slows down the sound velocity,whereas the latter does not display a strong dependence on the solution concentration. 展开更多
关键词 velocity sound SOAP
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