• Title/Summary/Keyword: Migration

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A Study on Fire Hazard by Metallic Migration (금속 마이그레이션에 의한 화재 위험성 연구)

  • Choi, Gyeong Won;Hyun, Byoung Soo;Kim, Sun Jae;Lim, Kyu Young;Woo, Seung Woo;Lee, Dong Kyu;Cho, Young Jin;Park, Jong Taek;Goh, Jae Mo;Park, Nam Kyu
    • Fire Science and Engineering
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    • v.33 no.6
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    • pp.114-119
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    • 2019
  • We found metallic migration phenomena at the fire scene in Printed circuit board (PCB) of LED light equipment which are commonly used. Accordingly we did this study. In order to generate rapidly metallic migration, we experiment the water drop test under low voltage (3.0 V) and a small amount of water condition. As a results of our experiment, we saw the growth of metallic migration of Copper and checked directly short of the PCB between isolated two poles by Cu migration. Finally we saw the shape of dendrite pattern by Cu migration using Scanning electron microscope (SEM) and analyzed that components via Energy dispersive Spectrometer (EDS).

Hydroacoustic Observations on the Diel Distribution and Activity Patterns of Fishes in the East China Sea II - Vertical Speed of Migration and Variation in Scattering Strength - (동중국해에 있어서 어족생물의 일주기적 여영행동특성에 관한 연구 II - 연직이동속도 및 산란강도의 변동 -)

  • 이대재
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.30 no.4
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    • pp.251-262
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    • 1994
  • The speed of vertical migration and the volume backscattering strength of the scattering layers during the evening and morning transitions between day and night were measured in November 1990-1992 in thermally stratified waters of the East China Sea. Acoustical measurements were carried out using a scientific echo-sounder operating at t재 frequencies of 25 and 100kHz, and using an echo-integration system connected with a micro-computer. Biological sampling was accomplished by bottom trawling to identify fish species recorded on the echo sounder, and the species and length compositions were determined. The values of scattering strength were allocated to group of fishes according to the fish traces on the echo recording paper and the species composition of trawl catches. The vertical velocities of migration derived from the changes in the depths and the values of peak scattering strength of the dense layer vertically migrating toward the bottom or toward the surface. The trawl data suggest that snailfish and fishing frog were the most abundant fishes in all research stations. As sunrise approached, the fish formed a strong concentration just above the thermocline. The the highest values of scattering strength in the entire water column appeared in the depth strata above the thermocline just before the begining of downward migration. As soon as the fish began to migrate downwards across the thermocline, the values of the scattering strength in the depth strata above the thermocline rapidly decreased, while the values for the scattering layer moving slowly toward the bottom gradually increased. During the 1992 surveys, the speed of the vertical migration was estimated to be 0.38m/min in the upward migration and 0.32m/min in the downward migration, respectively. That is the rate of vertical migration was slightly higher at dusk than at dawn. Similar migration patterns were observed on different stations and under different weather conditions during the surveys in 1990.

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Cigarette Smoke Extract-induced Reduction in Migration and Contraction in Normal Human Bronchial Smooth Muscle Cells

  • Yoon, Chul-Ho;Park, Hye-Jin;Cho, Young-Woo;Kim, Eun-Jin;Lee, Jong-Deog;Kang, Kee-Ryeon;Han, Jae-Hee;Kang, Da-Won
    • The Korean Journal of Physiology and Pharmacology
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    • v.15 no.6
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    • pp.397-403
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    • 2011
  • The proliferation, migration, cytokine release, and contraction of airway smooth muscle cells are key events in the airway remodeling process that occur in lung disease such as asthma, chronic obstruction pulmonary disease, and cancer. These events can be modulated by a number of factors, including cigarette smoke extract (CSE). CSE-induced alterations in the viability, migration, and contractile abilities of normal human airway cells remain unclear. This study investigated the effect of CSE on cell viability, migration, tumor necrosis factor (TNF)-${\alpha}$ secretion, and contraction in normal human bronchial smooth muscle cells (HBSMCs). Treatment of HBSMCs with 10% CSE induced cell death, and the death was accompanied by the generation of reactive oxygen species (ROS). CSE-induced cell death was reduced by N-acetyl-l-cysteine (NAC), an ROS scavenger. In addition, CSE reduced the migration ability of HBSMCs by 75%. The combination of NAC with CSE blocked the CSE-induced reduction of cell migration. However, CSE had no effect on TNF-${\alpha}$ secretion and NF-${\kappa}B$ activation. CSE induced an increase in intracellular $Ca^{2+}$ concentration in 64% of HBSMCs. CSE reduced the contractile ability of HBSMCs, and the ability was enhanced by NAC treatment. These results demonstrate that CSE treatment induces cell death and reduces migration and contraction by increasing ROS generation in normal HBSMCs. These results suggest that CSE may induce airway change through cell death and reduction in migration and contraction of normal HBSMCs.

TRAIL Suppresses Human Breast Cancer Cell Migration via MADD/CXCR7

  • Wang, Rui;Li, Jin-Cheng
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.7
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    • pp.2751-2756
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    • 2015
  • Background: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can specifically induce apoptosis limited to various cancer cells, so this reagent is considered a promising medicine for cancer therapy. TRAIL also exerts effects on non-apoptotic signals, relevant to processes such as metastasis, autophagy and proliferation in cancer cells. However, the mechanisms of TRAIL-regulated non-apoptotic signals are unclear. The purpose of this study was to investigate MADD/CXCR7 effects in TRAIL-mediated breast cancer cell migration. Materials and Methods: The ability of MADD/CXCR7 to regulate MVP signaling in TRAIL-mediated breast cancer cells migration was evaluated by transwell migration assay, quantitative RT-PCR, Western blotting and knock down experiments. Results: In this study, we found that treatment with TRAIL resulted in induced expression levels of MADD and CXCR7 in breast cancer cells. Knock down of MADD followed by treatment with TRAIL resulted in increased cell migration compared to either treatment alone. Similarly, through overexpression and knockdown experiments, we demonstrated that CXCR7 also positively regulated TRAIL-inhibited migration. Surprisingly, knock down of MADD lead to inhibition of TRAIL-induced CXCR7 mRNA and protein expression and overexpression of CXCR7 lead to the reduction of MADD expression, indicating that MADD is an upstream regulatory factor of TRAIL-triggered CXCR7 production and a negative feedback mechanism between MADD and CXCR7. Furthermore, we showed that CXCR7 is involved in MADD-inhibited migration in breast cancer cells. Conclusions: Our work defined a novel signaling pathway implicated in the control of breast cancer migration.

OTP-Based Dynamic Authentication Framework for Virtual Machine Migration (가상머신 마이그레이션을 위한 OTP 기반 동적인증 프레임워크)

  • Lee, Eun-Ji;Park, Choon-Sik;Kwak, Jin
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.27 no.2
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    • pp.315-327
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    • 2017
  • Security threats such as unauthorized access and data tampering can occur during the virtual machine migration process. In particular, since virtual machine migration requires users to transfer important data and infrastructure information, it is relatively risky to other cloud services in case of security threats. For this reason, there is a need for dynamic authentication for virtual machine migration. Therefore, this paper proposes an OTP-based dynamic authentication framework to improve the vulnerabilities of the existing authentication mechanism for virtual machine migration. It consists of a virtual machine migration request module and an operation module. The request module includes an OTP-based user authentication process and a migration request process to a data center when a user requests a migration. The operation module includes a secure key exchange process between the data centers using SPEKE and a TOTP-based mutual authentication process between the data center and the physical server.

Electrochemical Migration Characteristics of Sn-3.0Ag-0.5Cu Solder Alloy in NaBr and NaF Solutions (NaBr 및 NaF 용액에 대한 Sn-3.0Ag-0.5Cu 솔더 합금의 Electrochemical Migration 특성)

  • Jung, Ja-Young;Jang, Eun-Jung;Yoo, Young-Ran;Lee, Shin-Bok;Kim, Young-Sik;Joo, Young-Chang;Chung, Tai-Joo;Lee, Kyu-Hwan;Park, Young-Bae
    • Journal of Welding and Joining
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    • v.25 no.3
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    • pp.57-63
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    • 2007
  • Electrochemical migration characteristics of Pb-free solder alloys are quantitatively correlated with corrosion characteristics in harsh environment conditions. In-situ water drop test and corrosion resistance test for Sn-3.0Ag-0.5Cu solder alloys were carried out in NaBr and NaF solutions to obtain the electrochemical migration lifetime and pitting potential, respectively. Sn-3.0Ag-0.5Cu solder alloy shows similar ionization and electrochemical migration behavior with pure Sn because of Ag and Cu do not migrate due to the formation of resistant intermetallic compounds inside solder itself. Electrochemical migration lifetime in NaBr is longer than in NaF, which seems to be closely related to higher pitting potential in NaBr than NaF solution. Therefore, it was revealed that electrochemical migration lifetime of Sn-3.0Ag-0.5Cu solder alloys showed good correlation to the corrosion resistance, and also the initial ionization step at anode side is believed to be the rate-determining step during electrochemical migration of Pb-free solders in these environments.

A Proposal of Efficient Method for Data Center Information System Migration (데이터센터 정보시스템 이전을 위한 효율적인 방안 제시)

  • Song, Min-Gu;Kim, Sun-Bae
    • Journal of Digital Convergence
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    • v.12 no.3
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    • pp.201-210
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    • 2014
  • Recently, the more complicated with the elements made of information system, the more dangerous in migration them. So it is need to accomplish information system migration systematically. According to the movement of public institution, a large scale of information system migration is in processing and will be made. In this paper, I would like to suggest the use of migration solution in order to speed & effect information system migration process. This will be provided the pursuit function of information system movement, movement location pursuit in real time, monitoring function through the situation room, separation migration possibility on the basis of business attribute. Therefore, if you use the suggested solution, it will be decreased trial and error & minimized the movement time.

Inhibitory Effect of Bodusan on $TNF-{\alpha}-induced$ Migration via Inhibition of Metalloproteinase Activity in Human Aortic Smooth Muscle Cells (보두산의 금속분해효소 활성 저해를 통한 사람 대동맥 평활근세포의 유주능 억제 효과)

  • Yun, Hyun-Jeong;Park, Sun-Dong
    • The Korea Journal of Herbology
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    • v.23 no.3
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    • pp.155-162
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    • 2008
  • Objectives : This study was evaluated to elucidate the inhibitory potential of Bodusan (BDS) and its components, Strychnos ignatii semen (SIS) and Glycyrrhizae Radix (GR), on human aortic smooth muscle cells (HASMC) migration and production of matrix metalloproteinase (MMP)-2 and MMP-9 by $TNF-{\alpha}$ treatment. Methods : Cytotoxic activity of BDS and its components on HASMC was using 5-(3-caroboxymeth- oxyphenyl)-2H-tetra-zolium inner salt (MTS) assay. Effect of BDS, SIS and GR on $TNF-{\alpha}-induced$ HASMC migration underside of matrigel filter was stained with hematoxylin-eosin. And total number of cells that migrated to the underside of the filter was counted. MMP-2 and MMP-9 activity was evaluated by gelatin zymography assay. Results : The matrigel migration assay showed that BDS effectively inhibited the $TNF-{\alpha}-induced$ migration of HASMC. Moreover, BDS significantly inhibited MMP-9 activity. Our present study demonstrates that BDS and its components inhibits $TNF-{\alpha}-induced$ HASMC migration and MMP-9 activity. The inhibitory effect of BDS extract is more potent than that of its component herb extracts. Conclusions : These results provide evidence that BDS has multiple effects in the inhibition of HASMC migration and may offer a therapeutic approach to block HASMC migration.

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A Relative Performance Index-based Job Migration in Grid Computing Environment (그리드 컴퓨팅 환경에서의 상대성능지수에 기반한 작업 이주)

  • Kim Young-Gyun;Oh Gil-Ho;Cho Kum Won;Ko Soon-Heum
    • Journal of KIISE:Computing Practices and Letters
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    • v.11 no.4
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    • pp.293-304
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    • 2005
  • In this paper, we research on job migration in a grid computing environment with cactus and MPICH-C2 based on Globus. Our concepts are to perform job migration by finding the site with plenty of computational resources that would decrease execution time in a grid computing environment. The Migration Manager recovers the job from the checkpointing files and restarts the job on the migrated site. To select a migrating site, the proposed method considers system's performance index, cpu's load, network traffic to send migration job tiles and the execution time predicted on a migration site. Then it selects a site with maximal performance gains. By selecting a site with minimum migration time and minimum execution time. this approach implements a more efficient grid computing environment. The proposed method Is proved by effectively decreasing total execution time at the $K\ast{Grid}$.

A multi-phase model for predicting the effective chloride migration coefficient of ITZ in cement-based materials

  • Yang, C.C.;Weng, S.H.
    • Advances in concrete construction
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    • v.1 no.3
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    • pp.239-252
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    • 2013
  • Mortar microstructure is considered as a three-phase composite material, which is cement paste, fine aggregate and interfacial transition zone. Interfacial transition zone is the weakest link between the cement paste and fine aggregate, so it has a significant role to determine the properties of cementitious composites. In this study, specimens (w/c = 0.35, 0.45, 0.55) with various volume fractions of fine aggregate ($V_f$ = 0, 0.1, 0.2, 0.3 and 0.4) were cast and tested. To predict the equivalent migration coefficient ($M_e$) and migration coefficient of interfacial transition zone ($M_{itz}$), double-inclusion method and Mori-Tanaka theory were used to estimate. There are two stages to estimate and calculate the thickness of interfacial transition zone (h) and migration coefficient of interfacial transition zone ($M_{itz}$). The first stage, the data of experimental chloride ion migration coefficient ($M_s$) was used to calculate the equivalent migration coefficient of fine aggregate with interfacial transition zone ($M_e$) by Mori-Tanaka theory. The second stage, the thickness of interfacial transition zone (h) and migration coefficient of interfacial transition zone ($M_{itz}$) was calculated by Hori and Nemat-Nasser's double inclusion model. Between the theoretical and experimental data a comparison was conducted to investigate the behavior of interfacial transition zone in mortar and the effect of interfacial transition zone on the chloride migration coefficient, the results indicated that the numerical simulations is derived to the $M_{itz}/M_m$ ratio is 2.11~8.28. Additionally, thickness of interfacial transition zone is predicted from $10{\mu}m$, 60 to $80{\mu}m$, 70 to $100{\mu}m$ and 90 to $130{\mu}m$ for SM30, M35, M45 and M55, respectively.