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High-resolution swath bathymetry using MIMO sonar system

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Journal of Systems Engineering and Electronics 2014年第5期25卷 761-768页

作者： Xionghou liu Chao Sun Jie Zhuo Feng Yi zongwei liu Institute of Acoustic Engineering Northwestern Polytechnical University

For increasing the cross-track resolution, the multiple input multiple output （MIMO） technique is introduced into the swath bathymetry system and a new swath bathymetry approach using MIMO sonar is proposed. The MIMO sonar is composed of two parallel transmitting uniform linear arrays （ULAs） and a receiving ULA which is perpendicular to the former. The spacing between the two transmitting ULAs is equal to the product of the receiving sensor number and the receiving inter-sensor spacing. Furthermore, two narrowband linear frequency modulation （LFM） pulses, sharing the same frequency band but with opposite modulation slopes, are used as transmitting waveforms of the two transmitting ULAs. With such an array layout and transmitting signals, the MIMO sonar can sound a swath with the cross-track resolution doubling that of the traditional multibeam sonar using a Mills cross array. Numerical examples are provided to verify the effectiveness of the proposed approach.

关键词： bathymetry multibeam sonar multiple input multipleoutput (MIMO) sonar waveform diversity.

High-resolution bottom detection algorithm for a multibeam echo-sounder system with a U-shaped array

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Acta Oceanologica Sinica 2018年第7期37卷 78-84页

作者： JIANG Ying YANG Zhiguo liu zongwei YANG Chunmei Key Laboratory of Marine Science and Numerical Modeling The First Institute of OceanographyState Oceanic Administration Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology China National Deep Sea Center State Oceanic Administration

High-resolution approaches such as multiple signal classification and estimation of signal parameters via rotational invariance techniques（ESPRIT） are currently employed widely in multibeam echo-sounder（MBES）systems for sea floor bathymetry,where a uniform line array is also ***,due to the requirements in terms of the system coverage/resolution and installation space constraints,an MBES system usually employs a receiving array with a special shape,which means that high-resolution algorithms cannot be applied *** addition,the short-term stationary echo signals make it difficult to estimate the covariance matrix required by the high-resolution approaches,which further increases the complexity when applying the high-resolution algorithms in the MBES *** ESPRIT with multiple-angle subarray beamforming is employed to reduce the requirements in terms of the signal-to-noise ratio,number of snapshots,and computational *** simulations show that the new processing method can provide better fine-structure *** a highresolution bottom detection（HRBD） algorithm is developed by combining the new processing method with virtual array *** application of the HRBD algorithm to a U-shaped array is also *** computer simulations and experimental data processing results verify the effectiveness of the proposed algorithm.

关键词： high-resolution bottom detection multibeam echo-sounder subarray beamforming virtual array transformation

Underwater three-dimensional imaging using narrowband MIMO array

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Science China(Physics,Mechanics & Astronomy) 2013年第7期56卷 1346-1354页

作者： liu XiongHou SUN Chao YI Feng liu zongwei LI MingYang College of Marine Engineering Northwestern Polytechnical University

To obtain high cross-range resolution, the underwater 3-D acoustic imaging system usually requires a rectangular array with a great number of sensors and a large physical size. To reduce the sensor number and the array physical size simultaneously, this paper proposes a new underwater 3-D acoustic imaging approach based on a novel multiple-input multiple-output (MIMO) array. Specifically, the MIMO array is composed of four uniform linear arrays (ULAs) located on four sides of a rectangle. The transmitting array composed of two ULAs is located on a pair of opposite sides, and the receiving array composed of another two ULAs is located on the other two sides. Furthermore, narrowband waveforms coded with orthogonal polyphase sequences are employed as transmitting waveforms. When the subcode numbers in the polyphase coded sequences are sufficient, the MIMO array has the same 3-D imaging ability as a rectangular array, which has a two-time bigger size than that of the former. Consequently, the MIMO array can not only save a great number of sensors, but halve the array size, when compared to a rectangular array with the same cross-range resolution. Computer simulations are provided to demonstrate the effectiveness of the proposed imaging approach.

关键词： underwater acoustic imaging 3-D imaging multiple-input multiple-output (MIMO) array sparse array

Thermal expansion behavior of a β-LiAlSiO_4/Cu composite

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Rare Metals 2009年第1期28卷 82-85页

作者： WANG Lidong XUE zongwei liu Zhe FEI Weidong School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

A copper matrix composite reinforced by β-LiAlSiO4 with negative thermal expansion coefficient was fabricated using vacuum hot-pressed sintering technique. The thermal expansion behavior of the composite was investigated, and the average residual stress in the matrix was analyzed by a simple model. The results indicate that the residual stress in the matrix affects the thermal expansion properties. After heat treatment, the coefficient of thermal expansion （CTE） of the composite decreases greatly. The CTE of the composite after thermal cycling between 50-350°C is the lowest.

关键词： copper matrix composite β-eucryptite thermal expansion residual stress

基于机器学习的侵彻弹安全性量化分级方法初探

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北京理工大学学报 2025年第1期45卷 67-76页

作者：王锋汪衡刘宗伟王昭明谭力犁陆晓宇南京理工大学机械工程学院江苏南京210094 重庆红宇精密工业集团有限公司重庆402760 南京理工大学网络空间安全学院江苏南京210094

针对侵彻弹在子弹撞击、破片撞击及殉爆等机械冲击刺激条件下的安全性响应分析方法不健全、量化分级标准缺乏等问题,提出了一种基于机器学习的侵彻弹冲击安全性响应量化分级方法,基于Lee-Tarver装药反应度仿真数据和试验数据集,获得了... 详细信息

针对侵彻弹在子弹撞击、破片撞击及殉爆等机械冲击刺激条件下的安全性响应分析方法不健全、量化分级标准缺乏等问题,提出了一种基于机器学习的侵彻弹冲击安全性响应量化分级方法,基于Lee-Tarver装药反应度仿真数据和试验数据集,获得了装药反应度与冲击安全性响应等级的映射关系,实现了冲击安全性响应等级的定量预测,并开展了典型侵彻弹的子弹撞击、破片撞击及殉爆验证试验.结果表明:仿真预测结果与试验结果吻合较好,证明了侵彻弹冲击安全性响应量化分级方法的有效性,可为侵彻弹的冲击安全性工程设计提供重要支撑.

关键词：侵彻弹冲击安全性量化分级数值模拟试验验证

Development Trends of Transmissions for Hybrid Electric Vehicles Using an Optimized Energy Management Strategy

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Automotive Innovation 2018年第4期1卷 291-299页

作者： Tianze Shi Fuquan Zhao Han Hao zongwei liu Tsinghua Automotive Strategy Research Institute Tsinghua UniversityBeijing 100084China State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China

Energy conservation and emissions reduction have become increasingly significant for automobiles due to the severity of the current energy *** electric vehicle(HEV)technology is one of the most promising *** study investigated the total efficiency of a HEV *** improve the total efficiency,the engine should be regulated to work at its highest efficiency and drive the wheels directly as much as *** accomplish this,we developed an energy management strategy based on the direct drive area(DDA)of the engine’s efficiency *** typical HEV models were built to compare the fuel consumption using DDA and rule-based ***,the function of the HEV transmission system with DDA was *** transmission in a HEV should regulate the engine to work at its highest efficiency as much as possible,which is rather different than the regulation in an internal combustion engine *** functional change may lead to transmission systems with fewer gears but optimal gear *** this trend is realized,the manufacturing cost of HEVs could be largely reduced.

关键词： HEV Direct drive area Energy management Transmission cost reduction

Identification of Antarctic minke and killer whales with passive acoustic monitoring in Prydz Bay, Antarctica

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Journal of Oceanology and Limnology 2022年第2期40卷 485-495页

作者： Ying JIANG Lian-Gang LÜ zongwei liu Chunmei YANG Jingsong GUO First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China Laboratory for Regional Oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Key Laboratory of Marine Science and Numerical Modeling Ministry of Natural ResourcesQingdao 266061China

Although four species of odontocete and four species of baleen whale have been recorded in Prydz Bay,their vocalizations have been rarely *** vocalizations were recorded during March 2017 in Prydz Bay,***-duck sounds,downsweeps,inverted“u”shape signals,whistles,pulsed sounds,and broadband clicks were ***-duck sounds and downsweeps were associated with Antarctic minke whales(Balaenoptera bonaerensis)based on visual *** between inverted“u”shape signals,biphonic calls,and clicks with vocalizations previously described for killer whales(Orcinus orca)lead us believe the presence of Antarctic killer *** to sound structures,signal characteristics,and recording location,Antarctic type C killer whales were the most probable candidates to produce these detected *** represent the fi rst detection of inverted“u”shape signals in Antarctic waters,and the fi rst report of Antarctic killer whale in Prydz Bay based on passive acoustic *** co-existence of Antarctic minke and killer whales may imply that minke whales can detect diff erences between the sounds of mammal-eating and fi sh-eating killer *** descriptions of these underwater vocalizations contribute to the limited body of information regarding the distribution and acoustic behavior of cetaceans in Prydz Bay.

关键词： passive acoustic monitoring inverted“u”shaped signal killer whale Antarctic minke whales Prydz Bay type C

Observations and analysis of environment and acoustic field changed by the passage of typhoon Damrey in the Yellow Sea in 2012

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Science China Earth Sciences 2015年第12期58卷 2260-2270页

作者： YANG GuangBing Lü LianGang YUAN YeLi JIANG Ying liu zongwei YANG ChunMei liu HongNing CHEN Zhao South China Sea Institute of Oceanology Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Key Laboratory of Marine Science and Numerical Modeling The First Institute of OceanographyState Oceanic Administration

In order to investigate the environment and acoustic filed change induced by typhoon in shallow sea, we conducted two ex- periments just before and after the passage of typhoon Damrey, which is the strongest to affect the area north of the Yangtze River since 1949, in the Yellow sea in 2012. The data show that the temperature of the whole water column increases dramati- cally except the sea surface layer after the passage of Damrey while the salinity decreases obviously. The thermocline deepens and weakens, which leads to a change of internal wave activity. The transmission losses （TL） of the two experiments show that the environment change induced by typhoon can increase the TL as large as 8 dB at a distance of 9.2 km and depth of 15 m. The scintillation index （SI） of the sound intensity is simulated to estimate the change of the effect of internal wave activity on acoustic field showing that the SI decreases to a half after the typhoon＇s passage. The normal mode structures of the two experiments are also significanOy different due to the thermocline changes. In addition, the signal arrives earlier after the ty- phoon＇s passage due to the water temperature increase.

关键词： acoustic field typhoon Damrey thermocline internal wave Yellow Sea shallow sea

Analysis of Typical Automakers’ Strategies for Meeting the Dual-Credit Regulations Regarding CAFC and NEVs

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Automotive Innovation 2018年第1期1卷 15-23页

作者： Yue Wang Fuquan Zhao Yinshuo Yuan Han Hao zongwei liu Tsinghua Automotive Strategy Research Institute State Key Laboratory of Automotive Safety and EnergyTsinghua UniversityBeijing 100084China

The parallel corporate average fuel consumption(CAFC)and new energy vehicle(NEV)credit schemes that have been introduced by the Ministry of Industry and Information Technology of China is an innovative attempt to simultaneously regulate conventional gasoline vehicles(CGVs)and NEVs in the passenger vehicle sector that is expected to function as a long-term management mechanism for CGVs to be more energy-efficient and NEVs to be *** will have a significant impact on trends in China’s automotive industry and automakers’business *** the cases of four typical automakers with different levels of average fuel economy in their CGVs and advanced NEV production,scenario analysis has been applied to generate these automakers’alternatives in relation to compliance with the dual-credit regulations in force from 2017 to 2020 based on the Interim Measures on the Joint Management of CAFC and NEV Credits(Draft).These automakers’alternative approaches to compliance are ***,in view of the financial losses as a result of halted production if they fail to comply,the values of CAFC and NEV credits and corresponding influencing factors are analyzed from the automakers’***,the most cost-effective compliance strategies for these automakers are summarized and suggested improvements in the regulations are proposed for the government.

关键词： Automotive industry Dual-credit management Credit trading market Fuel consumption New energy vehicle