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4th International Conference on Materials Science and Information technology, MSIT 2014

作者： Li, Xiao Yan Liu, Sha Zhou, Zhi Min College of Life Science and Technology of Dalian University Liaoning Dalian 116622 China Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China

ISBN: (纸本)9783038351733

Ships have carried solid ballast for thousands of years in the form of rocks, sand or metal. In modern times, ships use water as ballast. It is more easier to load on and off a ship and more efficient and economical than solid ones. Ship fills with ballast water when it is empty of cargo, and the ballast water is discharged when it loads cargo. In ballast water, there are hundreds of organisms carried that cause problematic ecological effects outside of their natural range. Preventing the transfer of invasive species and coordinating a timely and effective response to invasions require cooperation and collaboration between governments. Considerable efforts had already made to formulate appropriate standards for ballast water management during the convention development process. © (2014) Trans Tech Publications, Switzerland.

关键词： Ships

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Comparative bioenergetics of diploid and triploid pacific oysters Crassostreas gigas at different temperatures

Comparative bioenergetics of diploid and triploid pacific oy...

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4th International Conference on Materials Science and Information technology, MSIT 2014

作者： Li, Xiao Yan Zhou, Zhi Min College of Life Science and Technology of Dalian University Liaoning Dalian 116622 China Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China

ISBN: (纸本)9783038351733

The energy budgets, assimilation and conversion efficiency of 1-year-old-triploid Pacific oysters Crassostrea gigas, were compared with those of sibling diploids to clarify the mechanism of energy metabolism. No significant difference was found between diploids and triploids in oxygen consumption. The net growth efficiencies of triploids and diploids were 37.4% and 33.9% respectively, and the gross growth efficiencies of them were 28.8% and 22.7%. The influence of ploidy and temperature on K1 was significant, but the variation of K2 may be attributable to ambient temperature. The ratio of gonad dry weight and dry tissue of triploids was 5% on average, and diploids about 25.6%. Our results showed that triploids, which do not reproduce and only have limited gonadal development, spend more energy for growth and more efficient in using energy than diploids do. © (2014) Trans Tech Publications, Switzerland.

关键词： Molluscs

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Modification to first-order Born approximation for improved prediction of scattered sound from weakly scattering objects

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Chinese Journal of Acoustics 2014年第3期33卷 228-238页

作者： ZHANG Peizhen WANG Shuozhong WANG Runtian CHEN Yunfei WANG Luxian School of Communication and Information Engineering Shanghai University School of Information Guangdong Ocean University Shanghai Acoustics Laboratory Chinese Academy of Sciences Key Laboratory for Underwater Test and Control Technology

When deriving the Fourier diffraction theorem based on the first-order Born approximation,the difference between wave number of the scattering object and that of the surrounding medium is ignored,causing substantial errors in sound scattering *** paper modifies the Born approximation by taking into account the amplitude and phase changes between the scattering object and the water due to the wave number *** changing the radius and center position of the sampling circle in the Fourier domain,accuracy of the predicted sound scattering is *** the modified Born approximation,the computed far-field directional pattern of the scattered sound from a circular cylinder is in good agreement with the rigorous *** calculations for several objects with different shapes are used to show applicability and effectiveness of the proposed method.

关键词： Modification to first-order Born approximation for improved prediction of scattered sound from weakly scattering objects

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Blind source separation of the fractional fourier domain in reverberation background

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Information technology Journal 2013年第7期12卷 1459-1463页

作者： Sun, Shijun Li, Xiukun Li, Wenwen Mu, Lin Science and Technology on Underwater Acoustic Laboratory Harbin Engineering University Harbin 150001 China Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China

To resolve the problem that reverberation signal usually seriously affect active sonar's detection performance, Blind Source Separation method of the Fractional Fourier Domain is adopted in this study. First, the Fractional Fourier Transform is used to enhance the signal-to-reverberation ratio. And then the separation condition is analyzed and target echo is separated from the received signal by using the Blind Source Separation method. At last, the highlight characteristic of the underwater target is extracted. Simulation and experiment data processing affirm the effectiveness of the proposed method. © 2013 Asian Network for scientific Information.

关键词： Blind source separation

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Simulation for range prediction of active sonar in shallow water

Simulation for range prediction of active sonar in shallow w...

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2013 International Conference on Mechanical and Electronics Engineering, ICMEE 2013

作者： Zhang, Liang Meng, Chun Xia Na, Jian Science and Technology on Underwater Test and Control Laboratory Dalian 11601 China

ISBN: (纸本)9783037858103

In shallow water the acoustic wave from ambient noise sources carries a large number of environment information based on the complicated reflection both on the surface and seabed interface. The sound speed profile is one of the influencing factors of sound propagation characteristic, while for a long distance the sound absorption coefficient of water medium has an important significance to propagation range. The simulation results show that in shallow water sound absorption of seabed, sound speed profile and sound absorption of water were taken into account, then range prediction of active sonar can be exactly obtained using normal-mode propagation. © (2013) Trans Tech Publications, Switzerland.

关键词： Forecasting

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High voltage triggered spark gap with repeatable gas filling structure

High voltage triggered spark gap with repeatable gas filling...

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International Symposium on Mechatronics and Applied Mechanics, ISMAM 2013

作者： Tian, Z.X. Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China

ISBN: (纸本)9783037858875

To resolve the problems of short working life and narrow operating voltage range of the spark gap with one-offin gas filling structure, a spark gap with repeatable gas filling structure was designed. The spark gap was composed of three electrodes and two gaps as well as gas filling devices. Electrodes structures adopted the form of field aberration three-electrode gas spark switch forming two discharge gaps between three electrodes of anode, cathode and triggering electrode. Gas filling devices were composed of fast connector, gas pipe, barometer and air valve, by which the gaps could be repeatedly charged and deflated from a hole at the center of anode. Working life is lengthened by exchanging gas, and operating voltage range is widened by changing gas pressure in a certain range. The spark gap was manufactured and applied successfully in a TEA CO2 laser with pulse energy 170J. The results prove the designs feasible. © (2013) Trans Tech Publications, Switzerland.

关键词： Anodes

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Geo-acoustic parameters inversion from vertical coherence characteristic of ambient noise

Geo-acoustic parameters inversion from vertical coherence ch...

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2013 International Conference on Mechanical and Electronics Engineering, ICMEE 2013

作者： Meng, Chun Xia Li, Gui Juan Zhang, Liang Science and Technology on Underwater Test and Control Laboratory Dalian 11601 China

ISBN: (纸本)9783037858103

In shallow sea the wave of ambient noise contains the information of environment acoustic field. In theory, vertical coherence, which is one of the numerous ambient noise field characters, can be used to invert geo-acoustic parameters because of its relative stability. The ambient noise data were collected in two different seasons using two vertical-laid hydrophones in shallow water. Then acoustic parameters of semi-infinite space seabed are inversed from the vertical coherence of measured ambient noise in the frequency range of 100Hz~3 kHz. The predicted vertical coherence curve of ambient noise, which is computed using inversed parameters, agrees with the measured curve by comparison. The experiment results show that geo-acoustic parameters can be inversed effectively by the vertical coherence of ambient noise. © (2013) Trans Tech Publications, Switzerland.

关键词： Acoustic fields

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Research on algorithm for blind source separation based on negentropy maximization

Research on algorithm for blind source separation based on n...

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2nd International Conference on Mechanical Engineering, Industrial Electronics and Informatization, MEIEI 2013

作者： Sun, Bo Qiu Tian, Zuo Xi National Key Laboratory of Science and Technology on Underwater Test and Control Dalian 116013 China

ISBN: (纸本)9783037858905

To detect week signal of underwater magnetic fields, we designed a negentropy maximization blind source separation algorithm based on the stochastic gradient descent algorithm by bring in a penalty factor. The simulation study demonstrates that the new algorithm is effective to separate the mixed-signal with high precision, to decrease the iterative calculation and to enhance the convergence rate. © (2013) Trans Tech Publications, Switzerland.

关键词： Blind source separation

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Rejection of Direct Blast Interference Based on Signal Phase-Matching Array Processing

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Journal of Electronic Science and technology 2013年第1期11卷 106-109页

作者： Yun-Fei Chen Zhen-Shan Wang Bing Jia Gui-Juan Li the Department of Ship Engineering Dalian University of Technology Key Laboratory for Underwater Test and Control Technology Key Laboratory for Underwater Test & Control Technology

In bistaic acoustic testing, there will be strong direct blast interference. An algorithm based on signal phase-matching array processing that rejects direct blast interference in bistatic acoustic testing has been studied, through which the object scattering signal is accurately extracted. Characteristics of bistatic acoustic testing and signal phase matching processing principle are fully integrated in this algorithm. Firstly, the direct blast interference is calculated from the receiving signal based on three subarrays signal phase matching processing. Secondly, the direct blast is rejected by subtraction from the receiving signal. In this way the limitations of the high signal to noise ratio that signal phase matching processing required for direct calculating the object scattering signal can be avoided. Simulation and sea trial results show that, when the ratio of signal to interference is greater than -20 dB, this algorithm of direct blast interference rejection based phase matching signal processing can accurately extract the object scattering signal.

关键词： Bistatic acoustic testing direct blast interference rejection signal phase matching processing.

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High Voltage Triggered Spark Gap with Repeatable Gas Filling Structure

High Voltage Triggered Spark Gap with Repeatable Gas Filling...

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2013 International Symposium on Mechatronics and Applied Mechanics(ISMAM 2013)

作者： Z.X.Tian Science and Technology on Underwater Test and Control Laboratory

To resolve the problems of short working life and narrow operating voltage range of the spark gap with one-offin gas filling structure,a spark gap with repeatable gas filling structure was *** spark gap was composed of three electrodes and two gaps as well as gas filling *** structures adopted the form of field aberration three-electrode gas spark switch forming two discharge gaps between three electrodes of anode,cathode and triggering *** filling devices were composed of fast connector,gas pipe,barometer and air valve,by which the gaps could be repeatedly charged and deflated from a hole at the center of *** life is lengthened by exchanging gas,and operating voltage range is widened by changing gas pressure in a certain *** spark gap was manufactured and applied successfully in a TEA CO2 laser with pulse energy *** results prove the designs feasible.

关键词： Spark gap Working life Gas filling structure Operating voltage Envelope

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