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| 1 | Sound propagation from the shelfbreak to deep water显示文摘Motivated by a phenomenon in an experiment conducted in the Northwestern Pacific indicating that the energy of the received signal around the sound channel axis is much greater than that at shallower depths,we study sound propagation from the transitional area(shelfbreak)to deep water.Numerical simulations with different source depths are first performed,from which we reach the following conclusions.When the source is located near the sea surface,sound will be strongly attenuated by bottom losses in a range-independent oceanic environment,whereas it can propagate to a very long range because of the continental slope.When the source is mounted on the bottom in shallow water,acoustic energy will be trapped near the sound channel axis,and it converges more evidently than the case where the source is located near the sea surface.Then,numerical simulations with different source ranges are performed.By comparing the relative energy level in the vertical direction between the numerical simulations and the experimental data,the range of the air-gun source can be approximated. | QIN JiXing ZHANG RenHe LUO WenYu PENG ZhaoHui LIU JianJun WANG DeJun | 2014 | Science China(Physics,Mechanics & Astronomy)2014，57，6： | 3 |
| 2 | The earthquake precursor detected in a granular medium and a proposed model for the propagation of precursive stress-strain signal显示文摘A way to detect the seismic precursor in granular medium is described and a model of propagation for precursive stress-strain signals is proposed.A strain sensor buried in a sandpit is used to measure a seismic precursor signal.The signal has been investigated and confirmed to originate from a specific earthquake.A comparison of simulated and experimental signals indicates that the signal results from the strain in the earth's strata.Based on the behavioral characteristics of granular materials,an analysis of why this method can be so sensitive to the seismic strain signal is undertaken and a model for the propagation of this stress-strain signal is proposed.The Earth's lithosphere is formed of tectonic plates,faults and fault gouges at their boundaries.In the case of the quasi-static mechanics of seismic precursory stress-strain propagation,the crustal lithosphere should be treated as a large-scale granular system.During a seismogenic event,accumulated force generates the stick-slip motion of adjacent tectonic plates and incrementally pushes blocks farther apart through stick-slip shift.The shear force released through this plate displacement causes soil compression deformation.The discrete properties of the sand in the sandpit lead to the sensitive response of the sensor to the deformation signal which enables it to detect the seismic precursor.From the analysis of the mechanism of the stress-strain propagation in the lithosphere,an explanation is found for the lack of signal detection by sensors installed in rocks.The principles and method presented in this paper provide a new technique for investigating seismic precursors to shallow-source earthquakes. | LU KunQuan HOU MeiYing WANG Qiang PENG Zheng SUN Wei SUN XiaoMing WANG YuYing TONG XiaoHui JIANG ZeHui LIU JiXing | 2011 | Chinese Science Bulletin2011，56，11： | 2 |
| 3 | Characterization and modeling of wind-dominated ambient noise in South China Sea显示文摘The action of wind on the sea surface plays an important role in the noise generation mechanism.Sea surface wind speed can be estimated accurately provided there is an accurate understanding of the relationship between the ocean ambient noise and wind speed.Many measurements and analyses of the wind dependence of ambient noise have been conducted.The approximate empirical rule given by Wenz[1]states that in the frequency band between 0.5and 5 kHz,the ambient sea-noise spectrum levels | DongGe Jiang ZhengLin Li JiXing Qin ZhaoHui Peng Hao Shao | 2017 | Science China(Physics,Mechanics & Astronomy)2017，60，12： | 1 |
| 4 | Pharmacokinetics of Enrofloxacin and Its Metabolite in Carp (Cyprinus carpio) After a Single Oral Administration in Medicated Feed显示文摘A precise and reliable analytical method of high performance liquid chromatography-tandem mass spectrometry(HPLCMS/MS)was developed to measure trace levels of enrofloxacin(ENR)and its major metabolite ciprofloxacin(CIP)in carp tissues.Optimized chromatographic separation was obtained on a Waters Xterra MS C_(18) reversed-phase column using gradient elution with methanol and 0.1%formic acid aqueous solution including 5mmolL^(-1) of ammonium acetate.The established method was applied to study the pharmacokinetics and distribution of ENR and CIP in tissues of carp following a single oral administration in feed at a dosage of 40mgkg^(-1) bw(body weight).Data were analyzed using DAS 2.0 dynamics software,and the experimental results suggest that ENR was rapidly absorbed and extensively distributed in carp tissues through systemic circulation,and the pharmacokinetic characteristics can be described with a two-compartment model.The elimination half-lives(t_(1/2β))from muscle,liver,gill,plasma and skin were 131,160,104,132 and 310 h,respectively.The areas under the drug concentration-time curves(AUC)for these tissues were 491,972,750,249 and 706hmgkg^(-1),respectively.The maximum concentration(C_(max))values were 13,29,37,9 and 5mgkg^(-1) with peak times(t_(max))of 8,4,4,2 and 4 h,respectively.Ciprofloxacin,the active metabolite of ENR,was also detected in carp tissues,indicating that only 1.54%of de-ethylation of ENR occurs in carp.At a water temperature of 18℃,the drug withdrawal time was determined to be no less than 24 d while the carp was fed at a single dosage of 40mgkg^(-1). | LIU Ying LI Zhaoxin ZHANG Dahai XING Lihong SUN Weihong SUN Xiaojie PENG Jixing ZHANG Yonggang LI Xianguo | 2023 | Journal of Ocean University of China2023，22，1： | 0 |
| 5 | First observation of domoic acid and its isomers in shellfish samples from Shandong Province,China显示文摘A total of 133 shellfish samples were collected in seven cities of Shandong Province,China,from May to October,2019.The domoic acid(DA)concentrations were determined by liquid chromatographytandem mass spectrometry(LC-MS/MS),and their distribution characteristics were investigated.DA concentration was detected high in over 1/3(36.1%)of the samples of four kinds of shellfish in all three seasons in range from 0 to 102μg/kg.The highest DA concentrations were 102,101,36.7,and 10.2μg/kg in Crassostrea gigas,Chlamys farreri,Mactra veneriformis,and Mytilus edulis,respectively.Geographically,Yantai(22.0μg/kg)and Weihai(16.9μg/kg)showed relatively high concentrations of DA,whereas Rizhao and Dongying presented only 0.85-and 1.76-μg/kg DA,respectively.DA concentrations in the shellfish samples were strongly related to seasonal changes,being significantly higher in autumn and summer than that in spring.The DA risk exposure assessments indicate that dietary seafood consumption did not pose a health threat to general human population.In addition,three isomers(isoA,isoD,isoE)and 5′-epimer DA were detected in 3.00%-15.80%of the shellfish samples.This study is the first to observe DA and its isomers in shellfish samples of Shandong Province.The results demonstrate that DA contamination is very common and should be continuously monitored. | Guanchao ZHENG Haiyan WU Mengmeng GUO Jixing PENG Yuxiu ZHAI Zhijun TAN | 2022 | Journal of Oceanology and Limnology2022，40，6： | 0 |
| 6 | Thermal processing induced release and degradation of paralytic shellfish toxin from mussels Mytilus edulis显示文摘Understanding the risk factors associated with shellfish consumption is a relevant public health concern because of the potential adverse ef fects of paralytic shellfish toxins(PSTs).This work aims to study the effects of the five most common heating treatments(steaming,boiling,frying,water-bath heating,and microwaving),for different processing times and temperature/power settings,on the content of PSTs in mussels(Mytilus edulis)collected in Qinhuangdao,China.The toxin concentration,removal percentages,and toxin distribution in the cooking liquor and meat were examined.The five processing modes effectively accelerated toxin release into the cooking liquor.The average percentage removal was 73.53%±16.50%from tissues.Microwaving led to the most significant toxin degradation among the methods tested.These findings should facilitate risk assessment of PSTs in mussels. | Chenfan DONG Haiyan WU Jixing PENG Mengmeng GUO Yuxiu ZHAI Zhijun TAN | 2022 | Journal of Oceanology and Limnology2022，40，6： | 0 |
| 7 | Geoacoustic inversion in shallow water by matching the vertical-particle-velocity显示文摘Bottom acoustic parameters are vital for studying sound propagation properties and their applications in ocean waveguides.The propagation properties and normal-mode structure of vertical-particle-velocity in an ocean environment with a thermocline in shallow water were studied in the Yellow Sea.The Results reveal that high energy of the verticalparticle-velocity exists at most depth except for near-bottom depth when the source and receiver are both below the thermocline.Moreover,high-order modes contribute more to the verticalparticle-velocity and vertical-particle-velocity-based matched-field-processing(MFP)inversion method can be highly sensitive to bottom parameters compared to sound pressure.Furthermore,the effects of the bottom absorption coefficient on the vertical-particle-velocity-based MFP inversion method are studied.It is shown that accurate sound velocity,density and water depth can be obtained only when the bottom absorption coefficient is set close to the real value during MFP.By using the vertical-particle-velocity signals recorded by vector hydrophones during the experiment and determining the bottom sound velocity,bottom density and water depth under different bottom absorption coefficients,stable inversion results were obtained.The transmission losses of the sound pressure at different ranges were used to invert the bottom absorption coefficients.The transmission losses of sound pressure calculated using the inverted bottom parameters are consistent with the experimental results obtained from the pressure hydrophones in the experiment. | TAN Peng SUN Mei QIN Jixing YANG Desen | 2023 | Chinese Journal of Acoustics2023，42，3： | 0 |
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