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应用物联网技术加速畜禽精准饲喂:从概念到实施

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Science Bulletin 2024年第14期69卷 2156-2160页

作者：苏家宜谭碧娥蒋宗勇吴德 C.M.nyachoti Sung Woo kim 印遇龙王婧 Key Laboratory of Hunan Province for the Products Quality Regulation of Livestock and Poultry College of Animal Science and TechnologyHunan Agricultural UniversityChangsha 410128China Institute of Animal Science Guangdong Academy of Agricultural SciencesGuangzhou 510640China Key Laboratory for Animal Disease-Resistant nutrition of the Ministry of Education of China and Animal Nutrition InstituteSichuan Agricultural UniversityChengdu 611130China Department of Animal Science University of ManitobaWinnipeg R3T 2N2Canada Department of Animal Science North Carolina State UniversityRaleigh 27695USA Laboratory of Animal nutritional Physiology and Metabolic Process Key Laboratory of Agro-Ecological Processes in Subtropical RegionNational Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry ProductionInstitute of Subtropical AgricultureChinese Academy of SciencesChangsha 410128China Yuelushan Laboratory Changsha 410128China

Maximizing sow reproductive performance is vital for ensuring healthy piglet supply,feed efficiency,and profitability,which requires understanding factors such as nutrition,disease control,genetics,herd management,and their *** is well documented that most reproductive issues in sows stem from extreme fluctuations in body reserves[1].Thus,optimizing reproduction should prioritize regulating body reserves and making continuous nutritional adjustments throughout a sow’s life[1,2].However,the traditional one-size-fits-all feeding strategy may not meet individual sow needs under varying *** feeding strategy leads to nutrient under-or over-feeding,which may result in a lack of performance and health issues on the one hand,and economic loss and negative environmental effects on the other.

关键词： feeding extreme reserves

CO_2 laser-micro plasma arc hybrid welding for galvanized steel sheets

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Transactions of nonferrous Metals Society of China 2011年第A01期21卷 47-53页

作者： C.H.kim Y.n.AHn J.H.kim Advance Welding & Joining Research Group Korea Institute of Industrial Technology Incheon 406-840 South Korea

A laser lap welding process for zinc-coated steel has a well-known unsolved problem-porosity formation. The boiling temperature of coated zinc is lower than the melting temperature of the base metal, which is steel. In the autogenous laser welding, the zinc vapor generates from the lapped surfaces expels the molten pool and the expulsion causes numerous weld defects, such as spatters and blow holes on the weld surface and porosity inside the welds. The laser-arc hybrid welding was suggested as an alternative method for the laser lap welding because the arc can preheat or post-beat the weldment according to the arrangement of the laser beam and the arc. CO2 laser-micro plasma hybrid welding was applied to the lap welding of zinc-coated steel with zero-gap. The relationships among the weld quality and process parameters of the laser-arc arrangement, and the laser-arc interspacing distance and arc current were investigated using a full-factorial experimental design. The effect of laser-arc arrangement is dominant because the leading plasma arc partially melts the upper steel sheets and vaporizes or oxidizes the coated zinc on the lapped surfaces. Compared with the result from the laser-TIG hybrid welding, the heat input from arc can be reduced by 40%.

关键词： galvanized steel CO2 laser micro plasma hybrid welding

Mixing features in an electromagnetic rectangular micromixer for electrolyte solutions

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Journal of Hydrodynamics 2017年第4期29卷 668-678页

作者： M.M.Wen C.n.kim Department of Mechanical Engineering Graduate School Kyung Hee University Department of Mechanical Engineering College of Engineering Kyung Hee University

In this study, a new magnetohydrodynamic（MHD） mixer for electrolyte solutions with pumping function is reported, and the mixing performance of the device for two different electrolyte solutions is numerically examined in a uniform magnetic field. Application of different potentials to different electrodes allows the current to be induced. The combination of the induced current and magnetic field yields Lorentz force, resulting in the fluid motion. The numerical simulation for the flows in the device is carried out with commercial software CFX. The validity of CFX code for the present numerical model is presented. The mixing performance of the fluids is investigated in many different cases with different combinations of input voltage of the electrode. This study shows that the mixing performance can be enhanced by applying spatially alternating positive and negative voltages to the electrodes. The present simulation results show that with a magnetic field intensity lower than 0.5 T, a voltage difference smaller than 2.0 V, and an electric conductivity of electrolyte solution of 1.5 S/m the pumping capabilities ranging 1.6×10^（-7）-3.6×10^（-6） kg/s and the mixing indexes higher than 0.90 can be obtained with sophisticated designs of the micromixer.

关键词： Mixer electrolyte solution Lorentz force CFX

Flow imbalance in MHD flows in splitting ducts with locally different electric conductivities of the walls

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Journal of Hydrodynamics 2018年第5期30卷 920-927页

作者： Yang Luo Mengqi Zhu C.n.kim Department of Mechanical Engineering Graduate School Kyung Hee University Department of Mechanical Engineering College of Engineering Kyung Hee University

In this study, three-dimensional liquid-metal magnetohydrodynamic splitting flows in a duct with one inflow channel and two outflow channels with locally different wall electric conductivities（different conductance ratios） are computationally examined. The numerical calculation is achieved with the use of CFX code, with a structured grid system chosen after a series of mesh independence tests. The detailed features of the MHD flows are depicted in a case where the electric conductivities of the two outflow ducts are quite different. Also, the interdependency among the current, fluid velocity, pressure and electric potential is elucidated in order to describe the electromagnetic characteristics of the liquid-metal flows. The result shows that the imbalance of the mass flow rate in the two outflow channels strongly depends on the wall conductivity（i.e., conductance ratio） of each outflow channel.

关键词： Liquid metal flow splitting duct flow imbalance numerical examination conductance ratio

Quality incentive based congestion control for multimedia communication over IP networks

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第z1期7卷 7-12页

作者： JOHAnSEn Stian kim Anna n. PERKIS Andrew Centre for Quantifiable Quality of Service in Communication Systems norwegian University of Science and Technology Trondheim N-7034Norway

In this paper we introduce a framework for using quality as an incentive to promote proper application level congestion control. Through integrating a joint-source channel coder and feedback-based congestion control scheme, we are able to construct accurate and efficient quality incentives. The framework is applicable in all network architectures where end-to-end congestion control may be used, and is as such not specific to either best-effort or traffic class-based architectures. The concept is presented along with preliminary simulations that highlight the resulting rate control accuracy. We also discuss how to implement some well-known congestion control schemes within our framework.

关键词： Congestion control, Incentives, Video communication, Joint source/channel coding, Unequal error protection

Temperature segregation and its impact on the quality and performance of asphalt pavements

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Frontiers of Structural and Civil Engineering 2018年第4期12卷 536-547页

作者： Minkyum kim Pranjal PHALTAnE Louay n.MOHAMMAD Mostafa ELSEIFI Louisiana Transportation Research Center Louisiana State UniversityLA 70808USA Department of Civil and Environmental Engineering Louisiana State UniversityLA 70808USA

Temperature segregation is non-uniform temperature distributionacross the uncompacted asphalt mat during paving operations and mayhave detrimental effects on the quality and performance of asphaltpavements. However, many research studies conducted across the UShave reported mixed observations regarding its effects on the initialquality and long-term performance of asphalt pavements.?The objectiveof this study was to determine the effects of the temperature segregationon the density and mechanical properties of Louisiana asphalt *** asphalt rehabilitation projects across Louisiana were selected.A multi-sensor infrared bar (Pave-IR) system and a hand-held portablethermal camera were used to measure the temperature of asphalt *** core samples were collected from various areas with varyingseverity levels of temperature segregation and tested for the density,fracture resistance (J ) by semi-circular bending(SCB), rut depth by wheel tracking, and dynamic modulus (|E*|) byindirect tension (IDT) devices.?Two distinctive patterns of non-uniformtemperature distribution were observed: a cyclic and irregular temperaturesegregations. Laboratory test results showed that highly temperaturesegregated asphalt pavements (i.e., temperature differentials ≥41.7°C) can have significantly lower densities and the mechanicalproperties than the non-segregated area, especially when the temperaturedifferentials are measured at compaction.

关键词： temperature segregation temperature differential pavement density semi-circular bending wheel tracking dynamic modulus

Effect of Reactivity of Quick Lime on the Properties of Hydrated Lime Sorbent for SO_2 Removal

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Journal of Materials Science & Technology 2009年第3期25卷 329-332页

作者： H.G. Shin H. kim Y.n. kim H.S. Lee Department of Materials Science and Engineering Seoul National University Material Analysis Team Korea Testing Laboratory School of Materials Science and Engineering Pusan National University

The hydration of quick lime and the sulfation of hydrated lime were carried out for verification of relationship between the reactivity of quick lime and the properties of hydrated lime as a sorbent. The effect of reactivity of quick lime was investigated with the change of calcination temperature and time. Results obtained showed that the temperature rise during the hydration of quick limes varied from 31 to 69℃ with the variation of calcination temperature and time. The specific surface area and the sulfation ability of hydrated lime prepared by hydration of quick lime showed a proportional relationship with the reactivity of quick lime. The hydrated lime which was prepared by hydration of quick lime calcined at 1100℃ had the highest reactivity and showed 41.53 m^2/g of the specific surface area, 0.16 cm^3/g of the pore volume and 87% of the removal efficiency for SO2 removal,

关键词： Reactivity Quick lime Hydrated lime Calcination Hydration Sorbent

Magnetohydrodynamic flows tuning in a conduit with multiple channels under a magnetic field applied perpendicular to the plane of flow

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Journal of Hydrodynamics 2017年第2期29卷 332-343页

作者： Y.Luo C.n.kim M.Q.Zhu Department of Mechanical Engineering Graduate SchoolKyung Hee UniversityYong-inKorea Department of Mechanical Engineering College of EngineeringKyung Hee UniversityYong-inKorea

In this study, three-dimensional liquid-metal magnetohydrodynamic flows in a conduit with multiple channels under a uniform magnetic field are numerically investigated. The geometry of the conduit is of a four-parallel-channels system including one inflow channel and three outflow channels. The liquid-metal flows into the inflow channel, then turns through 180° in the transi- tion segment, finally flows into three different outflow channels. This kind of channel system can induce counter flow and co-flow, which is rarely investigated before though the conceptual designs of duct flow in the blanket have suggested this type of flow. A structured grid system is chosen after a series of mesh independence tests in the present study. The axial velocity in the side layer near the first partitioning wall, located between the inflow channel and the first outflow channel, is the highest with the lowest electric potential formed therein. The pressure almost linearly decreases in the main flow direction, except in the transition segment. Moreover, the pressure gradient in the first outflow channel is the largest among the three outflow channels. The interdependency of the current, fluid velocity, pressure, electric potential is examined in order to describe the electromagnetic characteristics of the liquid-metal flows.

关键词： Liquid-metal magnetohydrodynamics multiple channels

Optimal deployment schedule of an active twist rotor for performance enhancement and vibration reduction in high-speed flights

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Chinese Journal of Aeronautics 2017年第4期30卷 1427-1440页

作者： Young H.YOU Sung n.JUnG Chang J.kim Department of Aerospace Information Engineering Konkuk University Seoul 05019 Republic of Korea

The best active twist schedules exploiting various waveform types are sought taking advantage of the global search algorithm for the reduction of hub vibration and/or power required of a rotor in high-speed conditions. The active twist schedules include two non-harmonic inputs formed based on segmented step functions as well as the simple harmonic waveform input. An advanced Particle Swarm assisted Genetic Algorithm（PSGA） is employed for the optimizer. A rotorcraft Computational Structural Dynamics（CSD） code CAMRAD II is used to perform the rotor aeromechanics analysis. A Computation Fluid Dynamics（CFD） code is coupled with CSD for verification and some physical insights. The PSGA optimization results are verified against the parameter sweep study performed using the harmonic actuation. The optimum twist schedules according to the performance and/or vibration reduction strategy are obtained and their optimization gains are compared between the actuation cases. A two-phase non-harmonic actuation schedule demonstrates the best outcome in decreasing the power required while a four-phase non-harmonic schedule results in the best vibration reduction as well as the simultaneous reductions in the power required and vibration. The mechanism of reduction to the performance gains is identified illustrating the section airloads, angle-of-attack distribution, and elastic twist deformation predicted by the present approaches.

关键词： Active twist High-speed flight Hub vibration non-harmonic Power required