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Hydraulics of a multiple slit-type energy dissipater

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Journal of Hydrodynamics 2014年第1期26卷 86-93页

作者：吴建华姚莉马飞吴伟伟 College of Water Conservancy and Hydropower Engineering Hohai University Hydraulic Structures Design Division Hydrochina Huadong Engineering Corporation

With the constructions of high dam projects in China, the energy dissipation downstream of a dam becomes a serious concern. In this study, a multiple slit-type energy dissipater, with different reduction size slits in the outlet, is developed on the basis of conventional slit-type energy dissipaters, aiming to enhance the energy dissipation through the turbulence and the friction between the different layers of the jet flow and the air entrainment due to the increased surface of the flow to the air. The hydraulic characteristics of the energy dissipater are experimentally investigated by means of three sets of physical models in nine cases, to characterize the geometric parameters with suitable performance. The main concerns are the flow regime, the jet flow trajectory, the energy dissipation, the cavitation characteristics, and the flow choking. The results indicate that the dissipater enjoys a high energy dissipation ratio with suitable hydraulic performance comparing with the conventional slit-type energy dissipaters.

关键词： aerator cavity length fin lateral deflector

Depressed female cynomolgus monkeys(Macaca fascicularis) display a higher second-to-fourth(2D:4D)digit ratio

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Zoological Research 2019年第3期40卷 219-225页

作者： Wei Li Ling-Yun Luo Xun Yang Yong He Bin Lian Chao-Hua Qu Qing-Yuan Wu Jian-Guo Zhang Peng Xie Department of Neurology Army Medical Center of PLAChongqing 400042China Institute of Neuroscience Chongqing Medical UniversityChongqing 400016China Chongqing Key Laboratory of Neurobiology of Chongqing Medical University Chongqing 400016China Department of Neurology the Third Affiliated Hospital of Sun Yat-Sen University Yuedong HospitalGuangzhou Guangdong 514700China

This research aimed to provide evidenee of a relationship between digit ratio and depression status in the cynomolgus monkey(Macaca fascicularis).In stable cyno molgus mon key social groups,we selected 15 depressed monkeys based on depressive-like behavioral criteria and 16 normal control mon *** animals were video recorded for two weeks,with the duration and frequency of the core depressive behaviors and 58 other behaviors in 12 behavioral categories then evaluated via behavioral *** ger len gths from the right and left forelimb hands of both groups were measured by X-ray imagi *** ger length and digit ratio comparisons between the two groups were con ducted using Stude nt's *** terms of the durati on of each behavior,signifies nt differences emerged in“Huddling”and five other behavioral categories,including Ingestive,Amicable,Parental,Locomotive,and *** addition to the above five behavioral categories,we found that depressed mon keys spent less time in parental and rubbing back and forth behaviors than the control ***,the 4th fin gers were significantly Ion ger in the left and right hands in the control group relative to the depressed mon *** sec ond?to?fourth(2D:4D)digit ratio in the left and right forelimb hands was significantly lower in the control group tha n that in the depressed *** fin dings revealed significant differences in finger lengths and digit ratios between depressed mon keys and healthy controls,which concords with our view that relatively high fetal testosterone exposure may be a protective factor against developing depressive symptoms(or that low fetal testosterone exposure is a risk factor).

关键词： fin ger length Digit ratio Major depressive disorder Cynomolgus mon key

Video tracking method for three-dimen-sional measurement of a free-swimming fish

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Science China(Physics,Mechanics & Astronomy) 2007年第6期50卷 779-786页

作者： WU GuanHao & ZENG LiJiang State Key Laboratory of Precision Measurement Technology and Instruments,Department of Precision Instruments,Tsinghua University,Beijing 100084,China State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision Instruments Tsinghua University Beijing China

A video system for tracking a free-swimming fish two-dimensionally is introduced in this paper. The tracking is accomplished by simultaneously taking images from the ventral view and the lateral view of the fish with two CCD cameras mounted on two computer-controlled and mutually orthogonal translation stages. By processing the images recorded during tracking,three-dimensional kinematic parameters of the tail and pectoral fin of the fish in forward,backward and turning swimming modes are obtained.

关键词： fish, tracking, kinematics, tail, pectoral fin A video system for tracking a free-swimming fish two-dimensionally is introduced in this paper. The tracking is accomplished by simultaneously taking images from the ventral view and the lateral view of the fish with two CCD cameras mounted on two computer-controlled and mutually orthogonal translation stages. By processing the images recorded during tracking, three-dimensional kinematic parameters of the tail and pectoral fin of the fish in forward, backward and turning swimming modes are obtained. ……

AXIAL LOADS ACTING ON MANDREL IN COPPER RIFLED TUBE DRAWING PROCESS

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Transactions of Nonferrous Metals Society of China 1996年第1期6卷 54-56页

作者： Peng Dashu Yang Bin Wang Feiyong Yang Linbin Department of Materials Science and Engineering Central South University of TechnologyChangsha 410083

Stresses and axial loads acting on the mandrel in the copper rifled tube drawing process were analysed,and factors affecting on the axial loads on mandrel were *** show that the depth of the mandrel dragged into sizin... 详细信息

关键词： drawing copper rifled tube lubrication fin

Resistance Analysis of a Semi-SWATH Design Concept in Shallow Water

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Journal of Marine Science and Application 2017年第2期16卷 182-189页

作者： Arifah Ali Adi Maimun Yasser M. Ahmed Rahimuddin Marine Technology Center Department of Aeronautics Automotive & Ocean Engineering Universiti Teknologi MalaysiaSkudai 81310 UTM Malaysia Department of Naval Architecture and Marine Engineering Faculty of Engineering Alexandria University Alexandria 21526 Egypt Program Studi Teknik Sistem Perkapalan Universitas Hasanuddin Makassar 90245 Indonesia

Resistance analysis is an important analytical method used to evaluate the hydrodynamic performance of High Speed Craft (HSC). Analysis of multihull resistance in shallow water is essential to the performance evaluation of any type of HSC. Ships operating in shallow water experience increases in resistance because of changes in pressure distribution and wave pattern. In this paper, the shallow water performance of an HSC design concept, the semi-Small Waterplane Area Twin Hull (semi-SWATH) form, is studied. The hull is installed with fin stabilizers to reduce dynamic motion effects, and the resistance components of the hull, hull trim condition, and maximum wave amplitude around the hull are determined via calm water resistance tests in shallow water. These criteria are important in analyzing semi-SWATH resistance in shallow water and its relation to flow around hull. The fore fin angle is fixed to zero degrees, while the aft fin angle is varied to 0o, 5o, 10o, and 15o. For each configuration, investigations are conducted with depth Froude numbers (FrH) ranging from 0.65 to 1.2, and the resistance tests are performed in shallow water at the towing tank of UTM. Analysis results indicate that the resistance, wave pattern, and trim of the semi-SWATH hull form are affected by the fin angle. The resistance is amplified whereas the trim and sinkage are reduced as the fin angle increases. Increases in fin angle contribute to seakeeping and stability but affect the hull resistance of HSCs.

关键词： resistance wave height semi-SWATH shallow water fin stabilizers

Marxist Crisis Theory and the Rate of Profit in the U.S. Economy during 1975-2008

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Economic and Political Studies 2013年第1期1卷 44-78页

作者： FUSHENG XIE AN LI ANDONG ZHU School of Economics Renmin University of China Department of Economics University of Massachusetts Amherst School of Marxism Tsinghua University

The cyclical fall in the rate of profit reveals the basic mechanism of the cyclical fluctuation of the economy.A new synthesis of the Marxist crisis theory necessitates calculating the rate of profit as well as considering factors such as capital-labor relations,realization of value,the organic composition of capital,and money and *** studies suggest that the *** rate in real economy showed no signs of effective recovery during *** shrinking profit share caused by growing employment of non-production workers turns out to be the major factor contributing to the cyclical fall in the rate of profit,which in turn may be traced to the reorganization of the production process before the 1990s and the growing flexibility of employment relations after the *** long-term stagnation of the rate of profit,a new,financialised model of accumulation that heavily depends on increasing liquidity in the economy took shape in the United States,making the *** more *** current crisis is but a natural result of the intrinsic contradiction between the Fed’s efforts to encourage financialised accumulation and to maintain the dollar as a legitimate quasi international reserve currency.

关键词： Marxist theory of crisis rate of profit crisis fin

Numerical and experimental investigation of a new conceptual fluoride salt freeze valve for thorium-based molten salt reactor

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Nuclear Science and Techniques 2020年第2期31卷 28-41页

作者： Xin-Yue Jiang Hui-Ju Lu Yu-Shuang Chen Yuan Fu Na-Xiu Wang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

To improve the reliability and reduce energy consumption,a conceptual design of a freeze valve is proposed for the thorium-based molten salt reactor(TMSR)*** were utilized in this new design to enhance heat transfer and realize passive shut-off function,which could not be realized by the previous *** experimental apparatus using the fluoride salt FLiNaK was constructed to conduct a series of preliminary solidification and melting *** addition,the enthalpy-porosity method of ANSYS■Fluent solver was applied to simulate the solidification process of the salt at a specified operating *** distributions of the fluoride salt,solidification/melting time,and frozen plug effect were analyzed under natural convection heat transfer in an open *** calculated salt temperatures exhibited good agreement with the experimental *** results indicated that the range of effective operating temperature is 530-600℃ for the finned freeze *** this study,the ideal set operating temperature of the finned freeze valve was chosen as 560℃ to achieve competent ***,560℃ is additionally the highest set operating temperature for maintaining excellent cooling performance and sustaining deep-frozen condition of the salt *** this set operating temperature,the simulation data indicated that the molten salt in the flat part of the finned freeze valve will completely solidify at 10.5 *** percentage of solid salt in the flat and lower transitional parts of the valve reaches 29.60% in 30.0 ***,the surface temperature of the proposed freeze valve is 11.10% lower compared with that of the TMSR freeze valve at a cooling gas supply of 173 m^3/***,the new freeze valve was proven to be capable of reducing the energy consumption and realizing the passive shut-off function.

关键词： fin Natural convection Freeze valve Fluoride salt Solidification Molten salt reactor

Learning from Fish: Kinematics and Experimental Hydrodynamics for Roboticists

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International Journal of Automation and computing 2006年第4期3卷 325-335页

作者： George V.Lauder Peter G.A.Madden Museum of Comparative Zoology Harvard University CambridgeMA 02138USA

Over the past 20 years, experimental analyses of the biomechanics of locomotion in fishes have generated a number of key findings that are relevant to the construction of biomimetic fish robots. In this paper, we present 16 results from recent experimental research on the mechanics, kinematics, fluid dynamics, and control of fish locomotion that summarize recent work on fish biomechanics. The findings and principles that have emerged from biomechanical studies of fish locomotion provide important insights into the functional design of fishes and suggest specific design features relevant to construction of robotic fish-inspired vehicles that underlie the high locomotor performance exhibited by fishes.

关键词： Fish locomotion robotics fin hydrodynamics kinematics

Radiator Vibration Fatigue Analysis

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Journal of Electronics Cooling and Thermal Control 2017年第1期7卷 8-21页

作者： Toure Ismael Buyun Sheng Department of Mechanical and Electronic Engineering Wuhan University of Technology Wuhan China

This paper is the second step of our work. The first step presents a set of parametric studies performed on automotive radiators by designing different heat exchanger models. The analysis focuses on the cooling performance for automobile radiator by changing several dimensions of the radiator fin phase (P2.5, P2.4, P2.3, P2.2, and P2.1) as well as the importance of coolant flow lay-out on the radiator global performance [1]. The second step consists on the study of the vibration fatigue of the sample with the best heat dissipation performance we design (radiator P2.1). We use Hyper Mesh to proceed with the finite element model. Frequency response analysis is solved by using MSC. Nastran (MSC. MD. Nastran. v2010.1.3-MAGNiTUDE), fatigue durability ana-lysis by using MSC Fatigue. In this experiment, the frequency response of the unit load (the unit load is 1 g) is analyzed. Based on the analysis of the frequency response of the unit load, the fatigue life of the radiator is analyzed by the PSD (power spectral density) curve and the S-N curve. From our experiments results, we observe that the radiator we design meets the international requirements of fatigue vibration under automobile normal working condition.

关键词： Automobile Radiator Radiator fin S-N and PSD (Power Spectral Density) Curve Fatigue Durability Frequency Response