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Separation of primary solid phases from Al-Si alloy melts

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China Foundry 2014年第4期11卷 382-395页

作者： Ki young kim School of Energy Materials and Chemical EngineeringKorea University of Technology and EducationChungnam 330-708Korea

The iron-rich solids formed during solidification of Al-Si alloys which are known to be detrimental to the mechanical,physical and chemical properties of the alloys should be *** the other hand,Al-Si hypereutectic alloys are used to extract the pure primary silicon which is suitable for photovoltaic cells in the solvent refining *** of the important issues in iron removal and in solvent refining is the effective separation of the crystallized solids from the Al-Si alloy *** paper describes the separation methods of the primary solids from Al-Si alloy melts such as sedimentation,draining,filtration,electromagnetic separation and centrifugal separation,focused on the iron removal and on the separation of silicon in the solvent refining process.

关键词： separation Al-Si alloys primary solids iron removal silicon extraction

Mechanical properties of high-strength concrete subjected to high temperature by stressed test

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中国有色金属学会会刊：英文版 2009年第B09期19卷 128-133页

作者： Gyu-Yong kim young-Sun kim Tae-Gyu LEE Division of Architecture Engineering Chun gnam National University

Recently, the effects of high temperature on compressive strength and elastic modulus of high strength concrete were experimentally investigated. The present study is aimed to study the effect of elevated temperatures ranging from 20 ℃ to 700 ℃ on the material mechanical properties of high-strength concrete of 40, 60 and 80 MPa grade. During the strength test, the specimens are subjected to a 25% of ultimate compressive strength at room temperature and sustained during heating, and when the target temperature is reached, the specimens are loaded to failure. The tests were conducted at various temperatures (20-700 ℃) for concretes made with W/B ratios of 46%, 32% and 25%, respectively. The results show that the relative values of compressive strength and elastic modulus decrease with increasing compressive strength grade of specimen.

关键词：高强混凝土高温作用力学性能测试抗压强度温度升高弹性模量强度试验

Video Frame Prediction by Joint Optimization of Direct Frame Synthesis and Optical-Flow Estimation

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Computers, Materials & Continua 2023年第5期75卷 2615-2639页

作者： Navin Ranjan Sovit Bhandari Yeong-chan kim Hoon kim Iot and Big Data Research Center Incheon National UniversityYeonsu-guIncheon22012Korea 2Department of Electronics EngineeringIncheon National UniversityYeonsu-guIncheon22012Korea

Video prediction is the problem of generating future frames by exploiting the spatiotemporal correlation from the past frame *** is one of the crucial issues in computer vision and has many real-world applications,mainly focused on predicting future scenarios to avoid undesirable ***,modeling future image content and object is challenging due to the dynamic evolution and complexity of the scene,such as occlusions,camera movements,delay and *** frame synthesis or optical-flow estimation are common approaches used by ***,researchers mainly focused on video prediction using one of the *** methods have limitations,such as direct frame synthesis,usually face blurry prediction due to complex pixel distributions in the scene,and optical-flow estimation,usually produce artifacts due to large object displacements or obstructions in the *** this paper,we constructed a deep neural network Frame Prediction Network(FPNet-OF)with multiplebranch inputs(optical flow and original frame)to predict the future video frame by adaptively fusing the future object-motion with the future frame *** key idea is to jointly optimize direct RGB frame synthesis and dense optical flow estimation to generate a superior video prediction *** various real-world datasets,we experimentally verify that our proposed framework can produce high-level video frame compared to other state-ofthe-art framework.

关键词： Video frame prediction multi-step prediction optical-flow prediction delay deep learning

A NUMERICAL ANALYSIS OF THE VENTILATION PERFORMANCE FOR DIFFERENT VENTILATION STRATEGIES IN A SUBWAY TUNNEL

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Journal of Hydrodynamics 2012年第2期24卷 193-201页

作者： HUANG Yuan-dong LI chan kim chang Nyung School of Environment and Architecture University of Shanghai for Science and Technology China College of Engineering Kyung Hee University Yongin 449-701 Korea Graduate School Kyung Hee University Yongin 449-701 Korea Industrial Liaison Research Institute Kyung Hee University Yongin 449-701 Korea

An unsteady three-dimensional analysis of the ventilation performance is carried out for different ventilation strategies to find out a ventilation method with a high performance in a subway *** natural ventilation performance associated with a train-induced air flow in a subway tunnel is *** dynamic layering method is used to consider the moving boundary of a train in the current CFD *** geometries of the modeled tunnel and the subway train are partially based on those of the Seoul *** effects of the structure of the ventilation duct and the geometry of the partitions on the ventilation performance are *** results show that the combined ventilation ducts （to be designed）,and the partitioning blocks installed along the middle of tunnel （already in existences） are helpful for air *** study can provide some guidance for the design of ventilation ducts in a subway system.

关键词： ventilation performance subway tunnel train-induced air flow natural ventilation duct numerical analysis

Data Aggregation-based Transmission Method in Ultra-Dense Wireless Networks

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Intelligent Automation & Soft Computing 2023年第1期35卷 727-737页

作者： Dae-young kim Seokhoon kim Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea

As the Internet of Things(IoT)advances,machine-type devices are densely deployed and massive networks such as ultra-dense networks(UDNs)are *** devices attend to the network to transmit data using machine-type communication(MTC),whereby numerous,various are *** devices generally have resource constraints and use wireless *** this kind of network,data aggregation is a key function to provide transmission *** can reduce the number of transmitted data in the network,and this leads to energy saving and reducing transmission *** order to effectively operate data aggregation in UDNs,it is important to select an aggregation point *** total number of transmitted data may vary,depending on the aggregation point to which the data are ***,in this paper,we propose a novel data aggregation scheme to select the appropriate aggregation point and describe the data transmission method applying the proposed aggregation *** addition,we evaluate the proposed scheme with extensive computer *** performances in the proposed scheme are achieved compared to the conventional approach.

关键词： Data aggregation data transmission ultra-dense network machine-type communication Internet of Things

High-temperature Oxidation Behavior of Zircaloy-4 and Zirlo in Steam Ambient

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Journal of Materials Science & Technology 2010年第9期26卷 827-832页

作者： Hyung Hoon kim Jun Ho kim Jin young Moon Ho Seong Lee Jeong Joo kim young Suck Chai School of Materials Science and Engineering Kyungpook National University School of Mechanical Engineering Yeungnam University214-1 Dae-dongGyeongsan-si

The oxidation characteristics for Zircaloy-4 and Zirlo in the temperature range of 700-1200°C under steam supply condition were investigated by using a modified thermo-gravimetric *** specimens were oxidized for 3600 s at each temperature and then quenched in a *** oxidation rate constants were measured from the weight gains to evaluate the oxidation behavior in Zircaloy-4 and *** weight gain rates of Zirlo were lower than those of Zircaloy-4,leading to the low rate *** different oxidation behaviors between both cladding materials were considered to be due to the difference in their chemical compositions.

关键词： Zircaloy-4 Zirlo Oxidation

Current approaches and future directions in the management of pterygium

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International Journal of Ophthalmology(English edition) 2018年第5期11卷 709-711页

作者： Kyoung Woo kim Jae chan kim Graduate School of Chung-Ang University College of Medicine Department of Ophthalmology College of MedicineChung-Ang University Hospital

Pterygium,a common ocular surface disorder,has a complex pathophysiology that may mimic *** is altered expression of cell cycle/proliferation-related factors in pterygium ***,similar to cancer treatments,the management of pterygium ought to be multifactorial based on the patient’s *** therapeutic methods for pterygium are focused on surgical resection in conjunction with antimetabolite use,in addition tissue graft is usually performed in the context of the avoidance of bare ***,future directions in the management of pterygia will likely focus on genetic *** perspective views the pathogenesis of pterygium,its existing therapies as well as current and future challenges in its treatment.

关键词： pterygium tumor recurrence future directions

Comparison of mesophilic and thermophilic anaerobic digestions of thermal hydrolysis pretreated swine manure: Process performance,microbial communities and energy balance

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Journal of Environmental Sciences 2023年第4期126卷 222-233页

作者： Xiaohui Liu changmin Lee Jae young kim Department of Civil and Environmental Engineering Seoul National UniversitySeoul 08826Korea

Anaerobic digestion (AD) of swine manure (SM) commonly shows low biogas output and unsatisfactory economic performance. In this study, thermophilic AD (TAD, 50±1℃) was combined with thermal hydrolysis pretreatment (THP, 170℃/10 bar), to investigate its potential for maximizing biogas yield, securing successful digestion and microbial diversity, as well as improving energy balance. Four lab-scale continuously stirred tank reactors were operated for 300 days and compared with each other, i.e., reactor 1 (raw SM fed in mesophilic AD:RSM-MAD), reactor 2 (THP-treated SM fed in MAD:TSM-MAD), reactor 3 (RSM-TAD),and reactor 4 (TSM-TAD). The results showed that THP was efficient to increase methane production of SM, TSM-TAD mode led to the highest methane yield (129.8±40.5 mL-CH_(4)/gVS/day) among the tests (p 700 mg/L) or volatile fatty acids (> 6000 mg/L) accumulation compared with MAD in start-up phase, TSM-TAD treatment mode behaved a sustainable digestion process in a long-term operation. For TSM-TAD scenario, higher Shannon–Weaver (3.873) and lower Simpson index (0.061) indicated this mode ensured and enlarged the diversity of bacteria communities. Phylum Bathyarchaeota was dominant (59.3%-90.0%) in archaea community,followed by Euryarchaeota in the four reactors. RSM-MAD treatment mode achieved the highest energy output (4.65 GJ/day), TSM-TAD was less effective (-17.38 GJ/day) due to increased energy demands. Thus improving the energetic efficiency of THP units is recommended for the development of TSM-TAD treatment mode.

关键词： Thermal hydrolysis pretreatment Digestion temperature Process performances Microbial communities Energy balance

LoRa Backscatter Network Efficient Data Transmission Using RF Source Range Control

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Computers, Materials & Continua 2023年第2期74卷 4015-4025页

作者： Dae-young kim SoYeon Lee Seokhoon kim Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea Department of Software Convergence Soonchunhyang UniversityAsan31538Korea

Networks based on backscatter communication provide wireless data transmission in the absence of a power source.A backscatter device receives a radio frequency(RF)source and creates a backscattered signal that delivers data;this enables new services in battery-less domains with massive Internet-of-Things(IoT)*** is highly energy-efficient in the context of massive IoT ***,long-range(LoRa)backscattering facilitates large IoT services.A backscatter network guarantees timeslot-and contention-based ***-based transmission ensures data transmission,but is not scalable to different numbers of transmission *** contention-based transmission is used,collisions are *** reduce collisions and increase transmission efficiency,the number of devices transmitting data must be *** control device activation,the RF source range can be modulated by adjusting the RF source power during LoRa *** reduces the number of transmitting devices,and thus collisions and retransmission,thereby improving transmission *** performed extensive simulations to evaluate the performance of our method.

关键词： Backscatter communication LoRa backscatter RF source range control activated device control internet of things