检索结果-南通市图书馆

Evolution and global correlation for strontium isotopic composition of marine Triassic from Huaying Mountains,eastern Sichuan,China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2008年第4期51卷 540-549页

作者： ZuoWei Hu SiJing Huang HaiRuo Qing qingdong wang ChunMei wang XiaoYong Gao State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation Institute of Sedimentary Geology Chengdu University of Technology Chengdu 610059 China Department of Geology University of Regina Regina S4S 0A2 Canada

Strontium isotope stratigraphy (SIS) has progressively become an efficient chemostratigraphic tool in the research and correlation of global geological events, such as global sea level fluctuations, orogeny, and paleo... 详细信息

关键词： Triassic marine carbonate strontium isotope global correlation Huaying Mountains eastern Sichuan

Evolution of strontium isotopic composition of sea-water from Late Permian to Early Triassic based on study of marine carbonates,Zhongliang Mountain,Chongqing,China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2008年第4期51卷 528-539页

作者： HUANG SiJing Qing HaiRuo HUANG PeiPei HU ZuoWei wang qingdong ZOU MingLiang LIU HaoNian State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation Institute of Sedimentary GeologyChengdu University of TechnologyChengdu 610059China Department of Geology University of ReginaRegina S4S 0A2Canada

Collected from a Late Permian to Early Triassic sedimentary section in the Zhongliang Mountain of Chongqing, Southwest China, sixty marine carbonate samples were measured for the 87Sr/86Sr ratios, and corresponding evolution curve was constructed. The concentrations of SiO2, CaO, MgO, Mn and Sr are used to evaluate reservation of strontium isotopic composition for original seawater and the credi-bility of the dissolution method for sample preparation. The results show that most of the samples (except seven samples with the Mn/Sr ratios higher than 2) contain the original geochemistry signa-tures of ancient seawater. Compared to the published 87Sr/86Sr ratios from the Late Permian to Early Triassic, our database reported here is the largest and the curve constructed is the most complete. The strontium isotopic curve from Late Permian to Early Triassic is consistent globally and exhibits a gen-eral trend of steady increase during this period. The minimum of 87Sr/86Sr ratios (0.707011) occurs in the Late Permian (30 m in thickness below the Permian-Triassic boundary), and the maximum (0.708281), near the Early-Middle Triassic boundary. The lack of land plants and the rapid continental weathering result in the increase of 87Sr/86Sr ratios during the interval. The Permian-Triassic boundary in Zhongli-ang Mountain Section has been accepted internationally. The 87Sr/86Sr ratios of six samples near the boundary vary from 0.70714 to 0.70715 with an average of 0.70714, which is consistent with the value of 0.70715 (samples are from articulate brachiopod shells) from Korte et al. published in 2006 (within the error range in experiment). Accordingly, the strontium isotope composition in the Permian-Triassic boundary in this paper is of global significance. It can be confirmed that the 87Sr/86Sr ratios of the sea-water in the Permian-Triassic transition are in the range of 0.70714―0.70715.

关键词： Zhongliang Mountain Chongqing Late Permian-Early Triassic paleoseawater strontium isotope composition

Beam alignments based on the spectrum decomposition of orbital angular momentums for acoustic-vortex communications

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第12期31卷 296-304页

作者： Gepu Guo Xinjia Li qingdong wang Yuzhi Li Qingyu Ma Juan Tu Dong Zhang School of Computer and Electronic Information Nanjing Normal UniversityNanjing 210023China Haiying Enterprise Group Co. Ltd.Wuxi 214061China College of Ocean Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Institute of Acoustics Nanjing UniversityNanjing 210093China

Given the enhanced channel capacity of wave chirality,acoustic communications based on the orbital angular momentum(OAM)of acoustic-vortex(AV)beams are of significant interest for underwater data ***,the stringent beam alignment is required for the coaxial arrangement of transceiver arrays to ensure the accuracy and reliability of OAM *** avoid the required multiple measurements of the traditional orthogonality based algorithm,the beam alignment algorithm based on the OAM spectrum decomposition is proposed for AV communications by using simplified *** studies of the single-OAM and OAM-multiplexed AV beams show that the error of the OAM spectrum increases with the translation distance and the deflection angle of the transceiver *** achieve an ideal arrangement,two methods of the single-array translation alignment and the dual-array deflection alignment are developed based on the least standard deviation of the OAM spectrum(SD-OAM).By decreasing the SD-OAM towards zero using transceiver arrays of 16 transmitters and 16 receivers,accurate beam alignments are accomplished by multiple adjustments in three *** proposed method is also demonstrated by experimental measurements of the OAM dispersion and the SD-OAM for misaligned *** results demonstrate the feasibility of the rapid beam alignment based on the OAM spectrum decomposition by using simplified transceiver ring-arrays,and suggest more application potentials for acoustic communications.

关键词： acoustic-vortex beam beam alignment orbital angular momentum(OAM)spectrum least standard deviation acoustic communication

Pulling force of acoustic-vortex beams on centered elastic spheres based on the annular transducer model

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第5期29卷 318-325页

作者： Yuzhi Li qingdong wang Gepu Guo Hongyan Chu Qingyu Ma Juan Tu Dong Zhang School of Physics and Technology Nanjing Normal UniversityNanjing 210023China College of Ocean Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Institute of Acoustics Nanjing UniversityNanjing 210093China

To solve the difficulty of generating an ideal Bessel beam,an simplified annular transducer model is proposed to study the axial acoustic radiation force(ARF)and the corresponding negative ARF(pulling force)exerted on centered elastic spheres for acoustic-vortex(AV)beams of arbitrary *** on the theory of acoustic scattering,the axial distributions of the velocity potential and the ARF for AV beams of different orders generated by the annular transducers with different physical sizes are *** is proved that the pulling force can be generated by AV beams of arbitrary orders with multiple axial *** pulling force is more likely to exert on the sphere with a smaller k0a(product of the wave number and the radius)for the AV beam with a bigger topological charge due to the strengthened off-axis acoustic *** pulling force decreases with the increase of the axial distance for the sphere with a bigger *** pulling force areas with wider axial regions can be formed by AV beams using a bigger-sized annular *** theoretical results demonstrate the feasibility of generating the pulling force along the axes of AV beams using the experimentally applicable circular array of planar transducers,and suggest application potentials for multi-position stable object manipulations in biomedical engineering.

关键词： acoustic radiation force pulling force acoustic-vortex beams annular transducer model acoustic scattering

Helical particle manipulation based on power-exponent-phase acoustic vortices generated by a sector transducer array

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第6期32卷 333-341页

作者：王青东胡彦涛王胜利李洪宇 College of Ocean Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Department of Modern Architecture Linyi Vocational CollegeLinyi 276017China

The characteristics of traditional acoustic vortices(AVs) were verified by the cross-sectional axisymmetric pressure distributions with perfect phase spirals around the center pressure null. In order to generate a non-axisymmetric pressure distribution, the concept of power-exponent-phase was first introduced into the formation of AV beams, named “powerexponent-phase acoustic vortices(PAVs)” in this paper. Based on a ring-array of sector transducers, the helical distribution of the low-pressure valley in cross-sections of PAVs, which enables particles to move from a distant position to the center low-potential well along a certain spiral passageway, was proved theoretically. The particle manipulation behavior for PAVs with a power order of 2 is numerically modeled and experimentally confirmed. The results show that PAVs with a nonaxisymmetric spiral pressure distribution can be used to realize the directional transport of particles in an enlarged scope,suggesting prospective application potential in biomedical engineering.

关键词： acoustic vortices power-exponent-phase spiral potential well sector transducer array particle manipulation

Processing Seismic Ambient Noise Data to Obtain Reliable Surface Wave Dispersion Measurements

在线全文

学校读者我要写书评

暂无评论

Earthquake Research in China 2015年第2期29卷 214-224页

作者： Li Lingli wang Weitao Zhu Liangbao Chen Haopeng wang qingdong Miao Peng wang Jun Earthquake Administration of Anhui Province Mengcheng National Geophysical Observatory Institute of Geophysics CEA Department of Geophysics School of Geodesy and GeometricsWuhan University

Ambient noise tomography is a rapidly emerging field of seismological research. This paper presents the current status of ambient noise data processing and its development history over the past several years, with the intention to explain and justify this development through salient examples. The ambient noise data processing procedure can be divided into four principal phases： ① single station data preparation; ② cross- correlation and temporal stacking; ③ measurements of dispersion curves （ performed with frequency-time analysis for both group and phase speeds） ; ④ quality control, including SNR analysis and selection of the acceptable measurements. In addition, we provide a specific solution for a better use of the seismic station data to ambient noise study.

关键词： Seismic ambient noise Cross-correlation Rayleigh surface wave Dispersion curves

An Improved Micro Hard Disk Read-Write Channel Servo Signal Simulate System Design on FPGA

在线全文

学校读者我要写书评

暂无评论

An Improved Micro Hard Disk Read-Write Channel Servo Signal ...

Fireworks: a potential artificial source for studying near-surface site structure

2011 International Conference on Computer Science and Information Technology(ICCSIT 2011)

作者： qingdong wang Changsheng Xie Dexiu Huang Chun Liu Dep. of computer science HUST

ISBN: (纸本)9781612848334

It’s important to simulate micro hard disk read-write channel servo signal for design and test. This paper researches a programmable signal generator by an improved high integrated direct digital frequency synthesis (DDFS) technology to simulate servo signal for read-write channel of micro hard disk. This device use very large-scale integrated circuit FPGA (field-programmable logic) to integrate high speed PDSP (programmable digital signal processor) design and DDFS design. Test results indicate that this device has higher precision and sequence of signal, and the circuit need not connect filter and can output 2-256 order harmonious. The circuit design is simply, reliable, and programmable, compared with general design by separate parts design.

关键词： servo signal PDSP FPGA direct digital frequency synthesis (DDFS)

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Fireworks: a potential artificial source for studying near-s...

Large-scale particle trapping by acoustic vortices with a continuously variable topological charge

2022年中国地球科学联合学术年会

作者： qingdong wang Risheng Chu Minhan Sheng Qiaoxia Liu Geophysical Exploration Center China Earthquake Administration Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences

The near surface, or regolith, is normally a highly heterogeneous region that may induce the largest scattering effects seen in the propagation of seismic waves, thus is important to evaluate possible seismic impacts on infrastructures and hazard assessment. Seismic waves propagating from source to surface can be significantly affected by heterogeneities of the near-surface geology. These modified waves can lead to local amplification or attenuation effects of the wave amplitude at the surface.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第7期33卷 398-406页

作者：庄昊霏张清源胡格昊王青东杜立彬 College of Ocean Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Department of Radiology the Affiliated Hospital of Qingdao UniversityQingdao 266000China College of Electronic and Information Engineering Shandong University of Science and TechnologyQingdao 266590China

Strengthened directivity with higher-order side lobes can be generated by the transducer with a larger radius at a higher frequency. The multi-annular pressure distributions are displayed in the cross-section of the acoustic vortices(AVs)which are formed by side lobes. In the near field, particles can be trapped in the valley region between the two annuli of the pressure peak, and cannot be moved to the vortex center. In this paper, a trapping method based on a sector transducer array is proposed, which is characterized by the continuously variable topological charge(CVTC). This acoustic field can not only enlarge the range of particle trapping but also improve the aggregation degree of the trapped particles. In the experiments, polyethylene particles with a diameter of 0.2 mm are trapped into the multi-annular valleys by the AV with a fixed topological charge. Nevertheless, by applying the CVTC, particles outside the radius of the AV can cross the pressure peak successfully and move to the vortex center. Theoretical studies are also verified by the experimental particles trapping using the AV with the continuous variation of three topological charges, and suggest the potential application of large-scale particle trapping in biomedical engineering.

关键词： acoustic vortices sector transducer array trapping particle continuously variable topological charge