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Numerical analysis on thermal-fluidic characteristics of the magnetic fluid in a cavity using GSMAC (GSMAC법을 이용한 밀폐된 정방형관내 자성유체의 열-유동 특성에 관한 해석적 연구)

  • Seo, Jae-Hyeong;Lee, Moo-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.3
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    • pp.997-1002
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    • 2013
  • The article is aiming to investigate the thermal-fluidic characteristics of magnetic fluid in a cavity using GSMAC (generalized-simplified marker and cell method). The transport equations of the magnetic fluid are including the continuity equation, momentum equation and energy equation for natural convection and Maxwell equation and magnetization equation of magnetite nano-sized particles motion. In addition, the heat transfer characteristics such as temperatures and Nusselt numbers and flow characteristics such as streamlines and isotherms of the magnetic fluid were analyzed with the intensity and direction of the magnetic fields. As a result, the thermal-fluidic characteristics of the magnetic fluid in a cavity were could be controlled by the intensity and direction of the magnetic fields.

A Study on Improving the Fairness by Dropping Scheme of TCP over ATM (ATM상의 TCP 패킷 폐기정책에 따른 공정성 개선에 관한 연구)

  • Yuk, Dong-Cheol;Park, Seung-Seob
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.11S
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    • pp.3723-3731
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    • 2000
  • Recently, the growth of applications and services over high-speed Internet increase, ATM networks as wide area back-bone has been a major solution. The conventional TCP suite is still the standard protocol used to support upper application on current Internet and uses a window based protocol for flow control in the transport layer. When TCP data uses the UBR service in ATM layer, the control method is also buffer management. If a cell is discarded in ATM layer. one whole packet of TCP will be lost. Which is responsible for most TCP performance degradation and do not offer sufficiently QoS. To solve this problem, Several dropping strategies, such as Tail Drop, EPD, PPO, SPD, FBA, have been proposed to improve the TCP performance over ATM. In this paper, to improve the TCP fairness of end to end, we propose a packet dropping scheme algorithm using two fixed threshold. Under similar condition, we compared our proposed scheme with other dropping strategies. Although the number of VC is increased, simulation results showed that the proposed scheme can allocate more fairly each VC than other schemes.

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LAMP-3 (Lysosome-Associated Membrane Protein 3) Promotes the Intracellular Proliferation of Salmonella typhimurium

  • Lee, Eun-Ju;Park, Kwan-Sik;Jeon, In-Sook;Cho, Jae-Woon;Lee, Sang-Jeon;Choy, Hyun E.;Song, Ki-Duk;Lee, Hak-Kyo;Choi, Joong-Kook
    • Molecules and Cells
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    • v.39 no.7
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    • pp.566-572
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    • 2016
  • Lysosomes are cellular organelles containing diverse classes of catabolic enzymes that are implicated in diverse cellular processes including phagocytosis, autophagy, lipid transport, and aging. Lysosome-associated membrane proteins (LAMP-1 and LAMP-2) are major glycoproteins important for maintaining lysosomal integrity, pH, and catabolism. LAMP-1 and LAMP-2 are constitutively expressed in Salmonella-infected cells and are recruited to Salmonella-containing vacuoles (SCVs) as well as Salmonella- induced filaments (Sifs) that promote the survival and proliferation of the Salmonella. LAMP-3, also known as DC-LAMP/CD208, is a member of the LAMP family of proteins, but its role during Salmonella infection remains unclear. DNA microarray analysis identified LAMP-3 as one of the genes responding to LPS stimulation in THP-1 macrophage cells. Subsequent analyses reveal that LPS and Salmonella induced the expression of LAMP-3 at both the transcriptional and translational levels. Confocal Super resolution N-SIM imaging revealed that LAMP-3, like LAMP-2, shifts its localization from the cell surface to alongside Salmonella. Knockdown of LAMP-3 by specific siRNAs decreased the number of Salmonella recovered from the infected cells. Therefore, we conclude that LAMP-3 is induced by Salmonella infection and recruited to the Salmonella pathogen for intracellular proliferation.

Flow control on the near wake of a circular cylinder attached with control rods (제어봉 부착에 따른 원형실린더 근접 후류 유동제어에 관한 실험적 연구)

  • Gim, Ok-Sok;Lee, Gyoung-Woo
    • Journal of Navigation and Port Research
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    • v.32 no.6
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    • pp.453-458
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    • 2008
  • Flow characteristics of the control-rod-attached 2-dimensional circular cylinder was accomplished using by PIV techniques. model tests had been carried out with different diameters of control rods(d/D=0.1 through d/D=0.5). and the Reynolds number Re=15,000 based on the cylinder diameter(D=50mm) to predict the performance of the model and the two-frame grey-level cross-correlation method had been used to obtain the velocity distribution in the flow field. 50mm circular cylinder had been used during the whole experiments and measured results had been compared with each other. The measured results have been compared with each case. therefore this article identifies not only the mean velocity profiles but also the control effects of the control rods.

A Study of Improving Method for The Convergence Infra Build of Vehicle Management Using by RFID Technologies (RFID를 활용한 차량관리 융합 인프라 구축방안 연구)

  • Lee, Bong-Choon;Ha, Deock-Ho;Kim, Ki-Moon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.9
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    • pp.1539-1546
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    • 2008
  • In the present age, a vehicle works important part in our lives and economical domain that transport people, freights, and everything. And both of its number and value are increasing more and more. But user's convenience, control system could not be archived improvement than technological success. In this paper, we suggest some kinds of administrative agendas; simplifying executive processes, designing vehicle information system using by RFID which includes Ubiquitous skill and optical communication network. Especially, this paper suggests public vehicle control model which ran simplify every executive processes of vehicle's life in the newest method. There are many kinds of RFID applicative products about transportation. And a dual invest should be interrupted for economical purpose. So we also proposes some way for problems of these types.

The Effect of a Mechanical Chest Compressions for Out-of-hospital Advanced Cardiac Life Support (병원 전 전문심장소생술을 위한 기계적 가슴압박기의 효과)

  • Lee, Hyeon-Ji
    • Journal of Convergence for Information Technology
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    • v.9 no.11
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    • pp.227-233
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    • 2019
  • The purpose of this study is to evaluate the quality of chest compression by conducting comparison research between mechanical chest compressor(LUCAS) and manuale cardiopulmonary resuscitation(CPR) in a out-of-hospital environment and suggest effective advanced cardiac life support using mechanical chest compressors. For this, a out-of-hospital cardiac arrest was simulated with a team of 3 ambulance workers, and manuale CPR and CPR using LUCAS were performed on site and during transport in an ambulance. The research results are as follows: the comparison of manuale CPR between on site and in an ambulance revealed that on-site manuale CPR showed significant differences in the average compression depth, compression rate, and relaxation rate. Second, the comparison between manuale CPR and LUCAS in an ambulance showed significant differences in the average compression depth, compression rate, the number of compression per minute.

The Starting Characteristics of the Steady Ejector-Diffuser System

  • Gopalapillai, Rajesh;Kim, Heuy-Dong;Matsuo, Shigeru;Setoguchi, Toshiaki
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.680-685
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    • 2008
  • The ejector is a simple device which can transport a low-pressure secondary flow by using a high-pressure primary flow. In general, it consists of a primary driving nozzle, a mixing section, and a diffuser. The ejector system entrains the secondary flow through a shear action generated by the primary jet. Until now, a large number of researches have been made to design and evaluate the ejector systems, where it is assumed that the ejector system has an infinite secondary chamber which can supply mass infinitely. However, in almost all of the practical applications, the ejector system has a finite secondary chamber implying steady flow can be possible only after the flow inside ejector has reached an equilibrium state after the starting process. To the authors' best knowledge, there are no reports on the starting characteristics of the ejector systems and none of the works to date discloses the detailed flow process until the secondary chamber flow reaches an equilibrium state. The objective of the present study is to investigate the starting process of an ejector-diffuser system. The present study is also planned to identify the operating range of ejector-diffuser systems where the steady flow assumption can be applied without uncertainty. The results obtained show that the one and only condition in which an infinite mass entrainment is possible is the generation of a recirculation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium at this point.

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Evaluation of Methane Emissions with Water Regime before the Cultivation Period in Paddy Fields

  • Park, Jun-Hong;Park, Sang-Jo;Kim, Jong-Su;Seo, Dong-Hwan;Park, So-Deuk;Kim, Jin-Ho
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.4
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    • pp.271-277
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    • 2015
  • Anaerobic decomposition of organic material in flooded rice fields produces methane, which escapes to the atmosphere primarily by transport through the rice plants. The annual amount of $CH_4$ emitted from a given area of rice is a function of the number and duration of crops grown, water regimes before and during cultivation period, and organic and inorganic soil amendments. Soil type, temperature, and rice cultivar also affect $CH_4$ emissions. The field experiment was conducted for three years to develop methane emission factor for water regime before the cultivation period from the rice fields. It was treated with three different water regimes prior to rice cultivation, namely: non-flooded pre-season < 180 days, non-flooded pre-season > 180 days, flooded per-season in which the minimum flooding interval is set to 30 days. Methane emission increased with days after transplanting and soil redox potential (Eh) decreased rapidly after flooding during the rice cultivation. The average methane emission fluxes were $5.47kg\;CH_4\;ha^{-1}day^{-1}$in flooded pre-season > 30 days, 5.04 in non-flooded pre-season < 180 days and 4.62 in non-flooded pre-season > 180. Methane emission flux was highly correlated with soil temperature and soil Eh. Rice yields showed no difference among treatments with water regime before the cultivation period.

Understanding Interfacial Charge Transfer Nonlinearly Boosted by Localized States Coupling in Organic Transistors (유기트랜지스터 내부 편재화 준위간 커플링에 의한 계면 전하이동의 비선형적 가속화 현상의 이해)

  • Han, Songyeon;Kim, Soojin;Choi, Hyun Ho
    • Journal of Adhesion and Interface
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    • v.22 no.4
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    • pp.144-152
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    • 2021
  • Understanding charge transfer across the interface between organic semiconductor and gate insulator gives insight into the development of high-performance organic memory as well as highly stable organic field-effect transistors (OFETs). In this work, we firstly unveil a novel interfacial charge transfer mechanism, in which hole transfer from organic semiconductor to polymer insulator was nonlinearly boosted by localized states coupling. For this, OFETs based on rubrene single crystal semiconductor and Mylar gate insulator were fabricated via vacuum lamination, which allows stable repetition of lamination and delamination between semiconductor and gate insulator. The surfaces of rubrene single crystal and Mylar film were selectively degraded by photo-induced oxygen diffusion and UV-ozone treatment, respectively. Consequently, we found that the interfacial charge transfer and resultant bias-stress effect were nonlinearly boosted by coupling between localized states in rubrene and Mylar. In particular, the small number of localized states in rubrene single crystal provided fluent pathway for interfacial charge transport.

Toxicities Demonstrated in Dams and Neonates following Intragastric Intubation of Polyethylene Microplastics to Pregnant Mice (폴리에틸렌 미세플라스틱의 임신 마우스 위내투여에 따른 모체 및 신생자 독성평가)

  • Song, YoungMin;Kim, ChangYul
    • Journal of Environmental Health Sciences
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    • v.47 no.5
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    • pp.446-453
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    • 2021
  • Background: Plastic particles less than 5 mm in diameter (microplastics) are well-known for causing various toxicities such as lung inflammation, oxidative stress, genotoxicity, and reproductive toxicity. As microplastics become smaller, they can move across cell membranes, the placenta, and the blood-brain barrier. Objectives: We evaluated the toxicities of polyethylene microplastics (PE-PMs) in dams and neonates through intragastric intubation of pregnant ICR mice. Methods: Low concentrations (0.01 mg/mouse/day) and high concentrations (0.1 mg/mouse/day) of polyethylene microplastics were administered from the ninth day of pregnancy to postnatal day seven. The control group was administered with distilled water. On the day of sacrifice, the weight of dams and neonates and the organ weight of neonates was measured. Further, acetylcholinesterase levels and glutathione peroxidase levels were evaluated by using a blood sample obtained on the sacrifice day. Results: No significant difference in the number of neonates was found, but the body weight gain of dams was seen to be lower in the low-dose group. On the other hand, we observed a consecutively declining trend in the weight gain and organ weight of neonates among the high-, control, and low-dose groups. Meanwhile, the serum acetylcholinesterase and glutathione peroxidase level were higher in the low-dose group compared to the control group. Further, the dose-dependent accumulation of microplastics in the organs of neonates revealed the transport of plastic particles from dams to their offspring. Conclusions: Although the exact mechanism of toxicity caused by microplastics could not be confirmed, it was validated that exposure to microplastics during pregnancy and lactation causes its migration between generations and accumulation throughout the body. Hence, it is necessary to evaluate the systemic toxicity of microplastics and assessment of co-morbidities such as second-generation toxicity, neurotoxicity, and depression following long-term exposure.