• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.86-89
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• 2004

Recently polymer arresters are being used widely but we don't have appropriate long term characteristics test methods. Therefore we need to develop special test facility to evaluate long term reliability of polymer arresters. It's polymeric housing can be degraded by environmental stress and the interface between housing and inner module can be affected by moisture absorption. This moisture absorption can cause leakage current and tracking in the interface. We developed multi stress accelerated ageing test facility to simulate field conditions including UV, temperature, humidity, voltage, salt fog and rain. In addition, we carried out field exposure test at the outdoor test yard and characteristics analysis of field operated specimens to evaluate accelerating factor of this accelerated aging test.

• 대한기계학회논문집A
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• 제36권7호
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• pp.751-757
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• 2012

사용조건에서 수명시험을 수행할 경우 시험시간이 많이 소요되므로 사용조건보다 가혹한 스트레스 조건을 추가하여 가속수명시험을 수행하면 시험시간을 단축시킬 수 있다. 수명에 영향을 미치는 스트레스를 선정하여 각 스트레스의 사용조건과 가속조건에서 시험을 수행할 경우 가속 스트레스간에 교호작용이 존재할 수 있다. 그러나 기존의 연구에서는 2가지 이상의 가속 스트레스를 부과하여 가속수명시험을 수행할 경우 교호작용을 고려하지 않은 경우와 가속 수명에 대한 모델식을 제시한 연구들이 대부분이다. 본 논문에서는 기계류 부품의 수명에 영향을 미치는 가속 스트레스를 선정한 후 교호작용을 고려한 시험계획에 따라 가속수명시험을 수행한 자료를 이용하여 가속 계수와 가속 스트레스간의 관계식을 산출하는 방법을 제시하고자 한다. 또한 본 논문에서 제시한 교호작용을 고려한 가속시험방법과 가속 계수를 산출할 수 있는 모델식을 이용하여 복합적인 가속수명시험 수행시 쉽게 적용하고 결과를 산출할 수 있는 기초가 될 것으로 기대된다.

• Archives of Plastic Surgery
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• 제38권5호
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• pp.567-575
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• 2011

Purpose: Acellular human dermis is very useful implant for use in plastic and reconstructive surgery. However, the volume of acellular human dermis graft is known to decrease for a long time. Basic fibroblast growth factor (bFGF) is a polypeptide that enhances the collagen synthesis and angiogenesis. In the current study we examined whether bFGF could improve the survival of acellular human dermis ($SureDerm^{(R)}$) by increasing angiogenesis of the graft. Methods: Forty rats were divided into two groups (control and bFGF). A 2-mm thick piece of $SureDerm^{(R)}$ was cut into smaller pieces that were $15{\times}5$ mm in size. Two subcutaneous pockets were made on the back of each rat. Grafts sprayed with bFGF were implanted in the bFGF group and injected with bFGF after transplantation every 3 days for 2 weeks. In the control group, the grafts were treated with phosphate-buffered saline (PBS) instead of bFGF. Four days, and 1, 4, and 12 weeks after the implantation, the grafts were harvested and gross and histologic examinations were performed. Inflammation grade, graft thickness, neocollagen density, and neocapillary count were measured. Results: The bFGF group displayed more rapid accumulation of inflammatory cells with a higher density of neocapillaries, and increased active collagen synthesis. After 12 weeks, the thickness of the grafts in the control and bFGF groups was $75.15{\pm}4.80%$ and $81.79{\pm}5.72%$, respectively, in comparison to the thickness before transplantation. There was a statistically significant difference between both groups ($p$ <0.05). Conclusion: bFGF was effective in reducing the absorption of acellular human dermal grafts by increasing angiogenesis and accelerating engraftment. In conclusion, bFGF may be a good tool for use in acellular human dermal graft transplantation for reconstructive surgery involving soft-tissue defects.

• 한국기후변화학회지
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• 제7권2호
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• pp.193-203
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• 2016

The importance of forecasting agricultural production is receiving attention while climate change is accelerating. This study suggested three types of crop yield forecasting model for major vegetable crops by using downscaled meteorological information of main production area on farmland level, which identified as limitation from previous studies. First, this study conducted correlation analysis with seven types of farm level downscaled meteorological informations and reported crop yield of main production area. After, we selected three types of meteorological factors which showed the highest relation with each crop species and regions. Parameters were deducted from meterological factor with high correlation but crop species number was neglected. After, crop yield of each crops was estimated by using the three suggested types of models. Chinese cabbage showed high accuracy in overall, while the accuracy of daikon and onion was quiet revised by neglecting the outlier. Chili and garlic showed differences by region, but Kyungbuk chili and Chungnam, Kyungsang garlic appeared significant accuracy. We also selected key meteorological factor of each crops which has the highest relation with crop yield. If the factor had significant relation with the quantity, it explains better about the variations of key meteorological factor. This study will contribute to establishing the methodology of future studies by estimating the crop yield of different species by using farmland meterological information and relatively simplify multiple linear regression models.

• 한국사회복지학
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• 제58권4호
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• pp.37-63
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• 2006

이 연구는 사회복지 조직간 협력에 영향을 미치는 협력관리 요인을 도출하여 그 의미를 찾고, 협력관리요인이 조직간 협력에 영향을 미치는지 검증하였다. 이론 검토를 통하여 공식 비공식 만남, 계약, 협력담당자 선정과 같은 협력관리내용은 기존의 조직요인이나 협력결과와 구분되는 개념으로 인식하였다. 조사 분석 결과, 협력관리 요인이 조직간 협력에 영향을 미치는 것으로 나타남으로써 조직간 협력관리의 정책수립이나 제도화가 조직간 협력을 더욱 활성화시킬 수 있음을 시사하였다. 연구결과를 통하여, 조직간 협력관리의 기술, 노하우, 이론의 개발을 주장하며, 조직간 협력을 활성화할 수 있는 관리활동을 서비스 조직 및 정부의 정책차원에서 제도화할 필요가 있음을 제안한다.

• Genes and Genomics
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• 제40권12호
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• pp.1287-1300
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• 2018

Hydrogen sulfide ($H_2S$), a small bioactive gas, has been proved functioning in plant growth and development as well as alleviation of abiotic stresses, which including promoting seed germination, accelerating embryonic root growth, regulating flower senescence, inducing stomatal closure, and defending drought, heat, heavy metals and osmotic stresses etc. However, the molecular functioning mechanism of $H_2S$ was still unclear. The primary objective of this research was to analyze the transcriptional differences and functional genes involved in the $H_2S$ responses. In details, 4-week-old plantlets in tissue culture of grapevine (Vitis vinifera L.) cultivar 'Zuoyouhong' were sprayed with 0.1 mM NaHS for 12 h, and then transcriptome sequencing and qRT-PCR analysis were used to study the transcriptional differences and functional genes involved in the $H_2S$ responses. Our results indicated that 650 genes were differentially expressed after $H_2S$ treatment, in which 224 genes were up-regulated and 426 genes were down-regulated. The GO enrichment analysis and KEGG enrichment analysis results indicated that the up-regulated genes after $H_2S$ treatment focused on carbon metabolism, biosynthesis of amino acids, and glycolysis/gluconeogenesis, and the down-regulated genes were mainly in metabolic pathways, biosynthesis of secondary metabolites, and plant hormone signal transduction. Analyzing the transcription factor coding genes in details, it was indicated that 10 AP2/EREBPs, 5 NACs, 3 WRKYs, 3 MYBs, and 2 bHLHs etc. transcription factor coding genes were up-regulated, while 4 MYBs, 3 OFPs, 3 bHLHs, 2 AP2/EREBPs, 2 HBs etc. transcription factor coding genes were down-regulated. Taken together, $H_2S$ increased the productions in secondary metabolites and a variety of defensive compounds to improve plant development and abiotic resistance, and extend fruits postharvest shelf life by regulating the expression of AP2/EREBPs, WRKYs, MYBs, CABs, GRIP22, FERRITINs, TPSs, UGTs, and GHs etc.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권5호
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• pp.302-309
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• 2000

The tracking characteristics of silicone rubber degraded by accelerated outdoor exposure employing a weather-o-meter were investigated. The tracking test was performed according to ICE Publ.587 method but the concentration of conductive solution was two times higher than IEC standard in order to accelerate the tracking failure. The number of large effective scintillation and the current of high voltage circuit were measured simultaneously. It was shown that the number of effective scintillation had valuable information of the tracking degradation state of silicone rubber, while the average current between electrodes could not provide information enough for diagnosis. Based upon the experimental results, it could be said that the key factor accelerating tracking failure was not Joule heating by current but pyrolysis by burning of silicone rubber, and that reduction of contact angle was due to chain scission which resulted in the free radicals of low molecules.

• Toxicological Research
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• 제19권3호
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• pp.161-172
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• 2003

Explanted mammalian cells perform a limited number of cell division in vitro and than are arrested in a state known as replicative senescence. Such cells are irreversibly blocked, mostly in the G1 phase of cell cycle, and are no longer sensitive to growth factor stimulation. Thus replicative senescence is defined as a permanent and irreversible loss of replicative potential of cells. For this characteristic, replicative senescence seems to evolve to protect mammalian organism from cancer. However, senescence also contributes to aging. It seems to decrease with age of the cell donor and, as a form of cell senescence, is thought to underlie the aging process. Extensive evidence supports the idea that progressive telomere loss contributes to the phenomenon of cell senescence. Telomeres are repetitive structures of the sequence (TTAGGG)n at the ends of linear chromosomes. It has been shown that the average length of telomere repeats in human somatic cells decreases by 30∼200 bp with each cell division. It is generally believed that when telomeres reach a critical length, a signal is activated to initiate the senescent program. This has given rise to the hypothesis that telomeres act as mitotic clocks to regulate lifespan. One proposes that cumulative oxidative stress, mainly reactive oxygen species generated from mitochondria, may mainly cause telomere shortening, accelerating aging. Here, the biological importance and mechanism of replicative senescence were briefly reviewed. Also it was summarized that how oxidative stress affects replicative senescence and telomere shortening.

• Asian-Australasian Journal of Animal Sciences
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• 제25권10호
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• pp.1473-1480
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• 2012

The Galactose-${\alpha}1$,3-galactose (${\alpha}1$,3Gal) epitope is responsible for hyperacute rejection in pig-to-human xenotransplantation. Human decay-accelerating factor (hDAF) is a cell surface regulatory protein that serves as a complement inhibitor to protect self cells from complement attack. The generation of ${\alpha}1$,3-galactosyltransferase (GGTA1) knock-out pigs expressing DAF is a necessary step for their use as organ donors for humans. In this study, we established GGTA1 knock-out cell lines expressing DAF from pig ear fibroblasts for somatic cell nuclear transfer. hDAF expression was detected in hDAF knock-in heterozygous cells, but not in normal pig cells. Expression of the GGTA1 gene was lower in the knock-in heterozygous cell line compared to the normal pig cell. Knock-in heterozygous cells afforded more effective protection against cytotoxicity with human serum than with GGTA1 knock-out heterozygous and control cells. These cell lines may be used in the production of GGTA1 knock-out and DAF expression pigs for xenotransplantation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1481-1484
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• 1997

The vehicle driving simulator expects vehicle motion with real-time simulation arise from driver's steering, accelerating, stopping and simulates motion of vehicl with visula, audio and washout algorithm. And it gives a vivid feeling to driver in reality. Vehicle driving simulator with vehicle integration control system is used for analysis of analysis of vehicle controllaility, steering capacity and safety in various pseudo environment alike. basides, it analyzeds vehicle safety factor dirver's reaction and promotes traffic safety without driver's own risks. The main proceduress of development of the vehicle driving simulator are classified by 3 parts. first the motion base system which can be generated by the motion queues, should be developed. Secondly, real-time vehicle software which can afford the vehicle dynamics, might be constructed. The third procedure is the integration of vehicle driing simulator which can be interconnected between visual systems with motion base. In this study, we are to study of the motion base for a vehicle driving simulator design and that of its real time control and using an extra gyro sensor and accelerometers to find a position and an orientatiion of the moving platform except for calculating forward kinematics. To drive the motion base, we use National Instruments corp's Labview software. Furthemore, we use analysis module for the vehicle motionand the washout algorithm module to consummate driving simulator, which can be driven by human in reality, so we are doing experimentally process about various vehicle motion conditon.