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| 1 | Research on the mechanics of underwater supersonic gas jets显示文摘An experimental research was carried out to study the fluid mechanics of underwater supersonic gas jets. High pressure air was injected into a water tank through converging-diverging nozzles (Laval nozzles). The jets were operated at different conditions of over-, full- and under-expansions. The jet sequences were visualized using a CCD camera. It was found that the injection of supersonic air jets into water is always accompanied by strong flow oscillation, which is related to the phenomenon of shock waves feedback in the gas phase. The shock wave feedback is different from the acoustic feedback when a supersonic gas jet discharges into open air, which causes screech tone. It is a process that the shock waves enclosed in the gas pocket induce a periodic pressure with large amplitude variation in the gas jet. Consequently, the periodic pressure causes the jet oscillation including the large amplitude expansion. Detailed pressure measurements were also conducted to verify the shock wave feedback phenomenon. Three kinds of measuring methods were used, i.e., pressure probe submerged in water, pressure measurements from the side and front walls of the nozzle devices respectively. The results measured by these methods are in a good agreement. They show that every oscillation of the jets causes a sudden increase of pressure and the average frequency of the shock wave feedback is about 5–10 Hz. | SHI HongHui1, WANG BoYi2 & DAI ZhenQing2 1 College of Mechanical Engineering and Automation, Zhejiang Sci-Tech University, Hangzhou 310018, China 2 State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China | 2010 | Science China(Physics,Mechanics & Astronomy)2010，53，3： | 22 |
| 2 | Approach to the endoscopic resection of duodenal lesions显示文摘Duodenal polyps or lesions are uncommonly found on upper endoscopy. Duodenal lesions can be categorized as subepithelial or mucosally-based, and the type of lesion often dictates the work-up and possible therapeutic options. Subepithelial lesions that can arise in the duodenum include lipomas, gastrointestinal stromal tumors, and carcinoids. Endoscopic ultrasonography with fine needle aspiration is useful in the characterization and diagnosis of subepithelial lesions. Duodenal gastrointestinal stromal tumors and large or multifocal carcinoids are best managed by surgical resection. Brunner's gland tumors, solitary Peutz-Jeghers polyps, and non-ampullary and ampullary adenomas are mucosally-based duodenal lesions, which can require removal and are typically amenable to endoscopic resection. Several anatomic characteristics of the duodenum make endoscopic resection of duodenal lesions challenging. However, advanced endoscopic techniques exist that enable the resection of large mucosally-based duodenal lesions. Endoscopic papillectomy is not without risk, but this procedure can effectively resect ampullary adenomas and allows patients to avoid surgery, which typically involves pancreaticoduodenectomy. Endoscopic mucosal resection and its variations(such as cap-assisted, cap-band-assisted, and underwater techniques) enable the safe and effective resection of most duodenal adenomas. Endoscopic submucosal dissection is possible but very difficult to safely perform in the duodenum. | Jonathan P Gaspar Edward B Stelow Andrew Y Wang | 2016 | World Journal of Gastroenterology2016，22，2： | 17 |
| 3 | Progresses and Prospects of Marine Geodetic Datum and Marine Navigation in China显示文摘Territorial water is a significant part of national sovereignty of China,thus the infrastructures of national space datum and location services should cover the sea areas except for the land areas.China has established relatively complete geodetic coordinate frame in land areas over the past decades,including the lastest developed China Geodetic Coordinate System 2000(CGCS 2000)with its reference frame and the national gravity datum 2000.However,the currently used geodetic infrastructures have not well covered the sea areas of China.The marine geodetic datum and marine navigation technologies need to be further developed and extended to satisfy the national demands of marine environment and resources detection,scientific investigation as well as marine economy development in new era of China.This paper mainly reviews the development and the progress of Chinese marine geodetic datum and marine navigation,analyses related key technologies in establishing our national marine geodetic datum.Some current trends and future directions for independently developing our national marine geodetic datum and marine navigation technologies are discussed. | Yuanxi YANG Tianhe XU Shuqiang XUE | 2018 | Journal of Geodesy and Geoinformation Science2018，1，1： | 16 |
| 4 | Underwater Explosion Treatment of Marine Soft Foundation显示文摘The consolidation of soft foundation is a problem that commonly appears in harbor construction engineering on muddy coast. Introduced in this paper is the experimental study on underwater explosion treatment of soft foundation, including the regulations of explosion hollow development and medium movement, the law of similarity of densification and settlement of filled stone mass by shock wave pressure and explosion energy and their construction technologies, etc. A number of projects have been completed by applying this new technique, and the technique itself has been proved practicable. | Zheng, Zhemin Yang, Zhengsheng Jin, Liu | 1991 | China Ocean Engineering1991，6，2： | 16 |
| 5 | 浅水域探测型无人水下航行器波浪能发电系统设计显示文摘为了实现浅水域探测型无人水下航行器(Unmanned underwater vehicle,UUV)探测设备水下长时间工作,提出波浪能发电系统,可以将近水面的波浪能收集转化为电能。详细叙述永磁发电机的原理结构及设计参数;根据Lagrange方程建立系统的数学模型;采用Runge-Kutta方法求解简化的运动方程,研究不同海况条件下对发电性能的影响。研究结果表明提出的波浪能发电系统是合理可行的,在一般海况下,能够满足探测设备的能源需求。同时表明频率与幅度以及耦合横摇对发电性能影响比较大,而耦合垂荡对其影响基本可以忽略。研究结果将为后期波浪能发电系统的工程试验提供一定的理论依据。 | 丁文俊 宋保维 毛昭勇 赵晓哲 | 2015 | 机械工程学报2015，51，2： | 13 |
| 6 | Diagnostic and therapeutic applications of water-immersion colonoscopy显示文摘Colonoscopy techniques combining or replacing air insufflation with water infusion are becoming increasinglypopular.They were originally designed to reduce colonic spasms,facilitate cecal intubation,and lower patient discomfort and the need for sedation.These maneuvers straighten the rectosigmoid colon and enable the colonoscope to be inserted deeply without causing looping of the colon.Water-immersion colonoscopy minimizes colonic distension and improves visibility by introducing a small amount of water.In addition,since pain during colonoscopy indicates risk of bowel perforation and sedation masks this important warning,this method has the potential to be the favored insertion technique because it promotes patient safety without sedation.Recently,this water-immersion method has not only been used for colonoscope insertion,but has also been applied to therapy for sigmoid volvulus,removal of lesions,lower gastrointestinal bleeding,and therapeutic diagnosis of abnormal bowel morphology and irritable bowel syndrome.Although a larger sample size and prospective head-to-head-designed studies will be needed,this review focuses on the usefulness of waterimmersion colonoscopy for diagnostic and therapeutic applications. | Shinya Sugimoto Takeshi Mizukami | 2015 | World Journal of Gastroenterology2015，21，21： | 13 |
| 7 | Computational and experimental study on dynamic behavior of underwater robots propelled by bionic undulating fins显示文摘Bionic undulating fins, inspired by undulations of the median and/or paired fin (MPF) fish, have a bright prospective for un-derwater missions with higher maneuverability, lower noisy, and higher efficiency. In the present study, a coupled computa-tional fluid dynamics (CFD) model was proposed and implemented to facilitate numerical simulations on hydrodynamic ef-fects of the bionic undulating robots. Hydrodynamic behaviors of underwater robots propelled by two bionic undulating fins were computationally and experimentally studied within the three typical desired movement patterns, i.e., marching, yawing and yawing-while-marching. Moreover, several specific phenomena in the bionic undulation mode were unveiled and dis-cussed by comparison between the CFD and experimental results under the same kinematics parameter sets. The contributed work on the dynamic behavior of the undulating robots is of importance for study on the propulsion mechanism and control algorithms. | ZHOU Han, HU TianJiang*, XIE HaiBin, ZHANG DaiBing & SHEN LinCheng College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha 410073, China | 2010 | Science China(Technological Sciences)2010，53，11： | 12 |
| 8 | Underwater image enhancement based on red channel weighted compensation and gamma correction model显示文摘Due to the special characteristics of light in water,the information of the red channel is seriously attenuated in collected image.This causes other colors to dominate the image.This paper proposes an underwater image enhancement algorithm based on red channel weighted compensation and gamma correction model.Firstly,by analyzing the attenuation characteristics of RGB channels,the intensity and the edge information of red channel are compensated by weighting the attenuation coefficient ratio between different channels to correct the chromaticity.Then the gamma correction model is employed to stretch the intensity range to enhance the contrast which makes the image look clearer.The experimental results show that the proposed algorithm can correct the color cast effect and improve the contrast by nearly 2 times for the underwater images with too much red component attenuation. | Wending Xiang Ping Yang Shuai Wang Bing Xu Hui Liu | 2018 | Opto-Electronic Advances2018，1，10： | 10 |
| 9 | Fractional Fourier domain hopped communication method based on chirp modulation for underwater acoustic channels显示文摘To improve the data rate of underwater acoustic frequency-hopped communications, frequency hopping is applied to different orders of fractional Fourier domain(Fr FD), to enable non-intrusive, bandwidth-limited acoustic communications.An Fr FD frequency-hopped communication method based on chirp modulation, namely multiple chirp shift keying-Fr FD hopping(MCSK-Fr FDH), is proposed for underwater acoustic channels. Validated by both simulations and experimental results, this method can reach a bandwidth efficiency twice more than conventional frequency-hopped methods with the same data rate and anti-multipath capability, suggesting that the proposed method achieves a better performance than the traditional frequencyhopped communication in underwater acoustic communication channels. Results also show that in practical scenarios, the MCSKFr FDH system with longer symbol length performs better at the low signal-to-noise ratio(SNR), while the system with larger frequency sweeping range performs better at a high SNR. | Xingbin Tu Xiaomei Xu Zheguang Zou Liangliang Yang Jianming Wu | 2017 | Journal of Systems Engineering and Electronics2017，28，3： | 9 |
| 10 | Experimental Study on Free Spanning Submarine Pipeline Under Dynamic Excitation显示文摘Seismic load has a significant effect on the response of a free spanning submarine pipeline when the pipeline is constructed in a seismically active region. The model experiment is performed on an underwater shaking table to simulate the response of submarine pipelines under dynamic input. In consideration of the effects of the terrestrial and submarine pipeline, water depth, support condition, distance from seabed, empty and full pipeline, and span on dynamic response, 120 groups of experiments are conducted. Affecting factors are analyzed and conclnsions are drawn for reference. For the control of dynamic response, the span of a submarine pipeline is by far more important than the other factors. Meanwhile, the rosponse difference between a submarine pipeline under sine excitation and that under random excitation exists in experiments. | 李昕 刘亚坤 周晶 马恒春 朱彤 | 2002 | China Ocean Engineering2002，17，4： | 9 |
| 11 | Shipborne Underwater Acoustic Communication System and Sea Trials with Submersible Shenhai Yongshi显示文摘The Shipborne acoustic communication system of the submersible Shenhai Yongshi works in vertical, horizontal and slant channels according to the relative positions. For ease of use, an array combined by a vertical-cone directional transducer and a horizontal-toroid one is installed on the mothership. Improved techniques are proposed to combat adverse channel conditions, such as frequency selectivity, non-stationary ship noise, and Doppler effects of the platform's nonlinear movement. For coherent modulation, a turbo-coded single-carrier scheme is used. In the receiver, the sparse decision-directed Normalized Least-Mean-Square soft equalizer automatically adjusts the tap pattern and weights according to the multipath structure, the two receivers' asymmetry, the signal's frequency selectivity and the noise's spectrum fluctuation. The use of turbo code in turbo equalization significantly suppresses the error floor and decreases the equalizer's iteration times, which is verified by both the extrinsic information transfer charts and bit-error-rate performance. For noncoherent modulation, a concatenated error correction scheme of nonbinary convolutional code and Hadamard code is adopted to utilize full frequency diversity. Robust and lowcomplexity synchronization techniques in the time and Doppler domains are proposed. Sea trials with the submersible to a maximum depth of over 4500 m show that the shipborne communication system performs robustly during the adverse conditions. From the ten-thousand communication records in the 28 dives in 2017, the failure rate of the coherent frames and that of the noncoherent packets are both below 10%, where both synchronization errors and decoding errors are taken into account. | WU Yan-bo ZHU Min LIANG Tao WANG Wei YANG Bo HANG Linyuan LI Xin-guo LIU Ye-yao | 2018 | China Ocean Engineering2018，32，6： | 8 |
| 12 | Application of A* Algorithm for Real-time Path Re-planning of an Unmanned Surface Vehicle Avoiding Underwater Obstacles显示文摘This paper describes path re-planning techniques and underwater obstacle avoidance for unmanned surface vehicle(USV) based on multi-beam forward looking sonar(FLS). Near-optimal paths in static and dynamic environments with underwater obstacles are computed using a numerical solution procedure based on an A* algorithm. The USV is modeled with a circular shape in 2 degrees of freedom(surge and yaw). In this paper, two-dimensional(2-D) underwater obstacle avoidance and the robust real-time path re-planning technique for actual USV using multi-beam FLS are developed. Our real-time path re-planning algorithm has been tested to regenerate the optimal path for several updated frames in the field of view of the sonar with a proper update frequency of the FLS. The performance of the proposed method was verified through simulations, and sea experiments. For simulations, the USV model can avoid both a single stationary obstacle, multiple stationary obstacles and moving obstacles with the near-optimal trajectory that are performed both in the vehicle and the world reference frame. For sea experiments, the proposed method for an underwater obstacle avoidance system is implemented with a USV test platform. The actual USV is automatically controlled and succeeded in its real-time avoidance against the stationary undersea obstacle in the field of view of the FLS together with the Global Positioning System(GPS) of the USV. | Thanapong Phanthong Toshihiro Maki Tamaki Ura Takashi Sakamaki Pattara Aiyarak | 2014 | Journal of Marine Science and Application2014，13，1： | 8 |
| 13 | Bubble dynamics and its applications显示文摘Bubbles have very important applications in many fields such as shipbuilding engineering, ocean engineering, mechanical engineering, environmental engineering, chemical engineering, medical science and so on. In this paper, the research status and the development of the bubble dynamics in terms of theory, numerical simulation and experimental technique are reviewed, which cover the underwater explosion bubble, airgun bubble, spark bubble, laser bubble, rising bubble, propeller cavitation bubble, water entry/exit cavitation bubble and bubble dynamics in other fields. Former researchers have done a lot of researches on bubble dynamics and gained fruitful achievements. However, due to the complexity of the bubble motion, many tough mechanical problems remain to be solved. Based on the research progress of bubble dynamics, this paper gives the future research direction of bubble dynamics, aiming to provide references for researches related to bubble dynamics. | 王诗平 张阿漫 刘云龙 张帅 崔璞 | 2018 | Journal of Hydrodynamics2018，30，6： | 8 |
| 14 | Multi-AUV SOM task allocation algorithm considering initial orientation and ocean current environment显示文摘There is an ocean current in the actual underwater working environment. An improved self-organizing neural network task allocation model of multiple autonomous underwater vehicles(AUVs) is proposed for a three-dimensional underwater workspace in the ocean current. Each AUV in the model will be competed, and the shortest path under an ocean current and different azimuths will be selected for task assignment and path planning while guaranteeing the least total consumption. First, the initial position and orientation of each AUV are determined. The velocity and azimuths of the constant ocean current are determined. Then the AUV task assignment problem in the constant ocean current environment is considered. The AUV that has the shortest path is selected for task assignment and path planning. Finally, to prove the effectiveness of the proposed method, simulation results are given. | Da-qi ZHU Yun QU Simon X.YANG | 2019 | Frontiers of Information Technology & Electronic Engineering2019，20，3： | 8 |
| 15 | Hybrid LD and LED-based underwater optical communication: state-of-the-art, opportunities,challenges, and trends [Invited]显示文摘In this paper,the current research of an underwater optical wireless communication(UWOC)network is reviewed first.A hybrid laser diode(LD)and light-emitting diode(LED)-based UWOC system is then proposed and investigated,in which hybrid cluster-based networking with mobility restricted nodes is utilized to improve both the life cycle and throughput of the UWOC network.Moreover,the LEDs are utilized for the coarse alignment,while the LDs are used for high-precision positioning to reduce the difficulty of optical alignment.Finally,challenges and trends for UWOC are pointed out to provide some insight for potential future work of researchers. | 黄璇 杨昉 宋健 | 2019 | Chinese Optics Letters2019，17，10： | 8 |
| 16 | HYDRODYNAMIC BEHAVIOR OF AN UNDERWATER MOVING BODY AFTER WATER ENTRY显示文摘An experimental study was conducted to investigate the water entryphenomenon. A facility was designed to carry out the tests with the entry veloci-ties of around 352 m/s. Visualization, pressure ineasurement, velocity measurementand underwater impact test were performed to investigate the hydroballistic behav-ior of the underwater moving body, the underwater flow field, the supercavitation,etc.. This study shows that the motion of a high-speed underwater body is stronglythree-dimensional and chaotic. Furthermore, it is found that the distribution of thetrajectory deflection of the underwater projectile depends on the depth of water. Itis also found by measuring the deformation on a witness plate submerged in water,that the impact energy of an underwater projectile is reduced as it penetrates deeperinto water. | 施红辉 高见卓也 | 2001 | Acta Mechanica Sinica2001，17，1： | 7 |
| 17 | Measurement of the echo reduction for underwater acoustic passive materials by using the time reversal technique显示文摘A measuring method of the echo reduction of passive materials by using the time reversal(TR) technique is presented. To measure the echo reduction of a sample with this approach, the received signals are firstly focused according to the TR theory. Then, the sample is removed and the TR processing is again employed to realize the focus of the received signal.Finally, the echo reduction of the sample is evaluated with these focusing signals. Besides, to calibrate the measured echo reduction via the TR technique, a standard sample is employed to measure a constant coefficient that only depends on the measurement environment. An aluminum plate sample and a steel plate sample with the same size of 1.1 mxl.O m x0.005 m axe tested in a wave guide tank. The experimental results show that the calibrated values are well consistent with theoretical results under the free field at the measured frequency range of0.5-20 kHz. The relative errors of all the measured values are less than 10% and the values of the expanded uncertainty are less than 1.5 dB. The TR processing focuses the energy in spatial domain and temporal domain, so it can be used to measure the echo reduction of passive materials in the environments with reflections induced by boundaries and low frequency sources. | YAN Xiaowei LI Jianlong HE Zhiguang | 2016 | Chinese Journal of Acoustics2016，35，3： | 7 |
| 18 | Study of damage to a high concrete dam subjected to underwater shock waves显示文摘To study the effect of a strong underwater shock wave on a concrete dam, this research aims to improve hammer impact methods in model tests. Six 1:200 scale models were designed and tested under distributed impact loads. A device was deployed for a direct measurement of the impact force at the upstream face of the dams. The model dam bases were anchored to prevent displacement. The experimental results indicate that the top part of the concrete dam is a weak zone, and the impact failure initiates with a fracture on the top of the dam. The peak value of impact stress increases when the second crack appears in the concrete dam from the upstream face to the downstream face. And, the level of the second crack in the dam body is lower as the peak value of impact stress increases. In this study, dynamic analysis was conducted by calculating the results to verify the effectiveness of a device to directly measure the impact force. This method may be used to approximately forecast the damage of concrete dam and may also be useful in other engineering applications. | Lu Lu Li Xin Zhou Jing | 2014 | Earthquake Engineering and Engineering Vibration2014，13，2： | 7 |
| 19 | Application of a Stereo Constructed Wetland Mode to the Treatment of Slightly Polluted Source Water显示文摘[Objective] The study aimed to discuss the application of a stereo constructed wetland to the treatment of slightly polluted source water. [Method] In this study, a new stereo constructed wetland mode was put forward, and a pilot project of water ecological purification in Xinsheng River, the diversion channel of Shijiuyang Waterwork in Jiaxing City, were analyzed. Afterwards, the impact factors of water purification by the technology were discussed from water quality and quantity, season and climate, species configuration, management and maintenance. [Result] Under three different hydraulic loading conditions, the pilot project effectively improved water SD and DO level, and reduced SS, CODCr, NH3-N, TN and TP significantly in summer and autumn, so that effluent water quality reached surface water standard at Grade III. [Conclusion] The stereo constructed wetland mode composed of constructed wetland and underwater forest used to treat slightly polluted source water is feasible and has a good promotion prospect. | CHEN Yu-quan ZUO Zhuo GUO Xiao | 2012 | Meteorological and Environmental Research2012，3，12： | 7 |
| 20 | SEDIMENTARY ENVIRONMENT IN TAIWAN SHOAL显示文摘Taiwan Shoal sediments are well sorted and rounded medium-coarse sands eontaining a large amount of shell and beach rock fragments and basalt gravels, and are of deltaic, coastal and eolian origin. Underwater sand waves are formed by the combined tidal currents and are remolded by storm waves. | 蔡爱智 朱孝宁 李元密 蔡月娥 | 1992 | Chinese Journal of Oceanology and Limnology1992，10，4： | 7 |
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