• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.259-259
• /
• 2009

Surface contamination and leakage current have caused operating problems. A flashover in a substation may result in destruction of an insulator or many others electrical equipment. Engineering plastics have good characteristic (light weight, good productivity and little of void) as compare with epoxy or porcelain insulators. Outdoor insulator must have resistance to contamination. However, they are not suited to outdoor insulator by reason of being not good hydrophobic. RTV has a good property of hydrophobic and ATH has characteristic obstructing exothermic reaction. In order to reduce the incidence of insulator flashover and damage, the silicon rubber contained nano size ATH coat on surface of engineering plastics. In this paper, it compares resistance tracking of the engineering plastic coated RTV with that of non-coated engineering plastic and ATH filled composites performed much better than non-filled composites.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.1774-1779
• /
• 2005

Most of materials receive force in using, therefore, the characteristics of materials must be considered in system design not to occur deformation or destruction. Mechanical properties about materials can be expressed as responsible level of material itself under the exterior operation. Main mechanical properties is strength, hardness, ductility and stiffness etc. Currently, among major measure facilities to measure such mechanical properties, advanced indentation technique has focused in industrial areas as reason of nondestructive and easy applications for mechanical tensile properties and evaluation of residual stress of materials. This study is to find the optimum experimental condition about residual stress advanced indentation technique for accurate analysis of the welded joint of steel materials through indentation load-depth curve obtained from cruciform specimen experiment. Optimum selection was applied to the welded joint of real steel materials to give non-equi-biaxial stress state and compared with general residual stress analyzing method for verification.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.1449_1450
• /
• 2009

Surface contamination and leakage current have caused operating problems. A flashover in a substation may result in destruction of an insulator or many others electrical equipment. Engineering plastics have good characteristic (light weight, good productivity and little of void) as compare with epoxy or porcelain insulators. Outdoor insulator must have resistance to contamination. However, they are not suited to outdoor insulator by reason of being not good hydrophobic. RTV has a good property of hydrophobic and ATH has characteristic obstructing exothermic reaction. In order to reduce the incidence of insulator flashover and damage, the silicon rubber contained nano size ATH coat on surface of engineering plastics. In this paper, it compares resistance tracking of the engineering plastic coated RTV with that of non-coated engineering plastic and ATH filled composites performed much better than non-filled composites.

• 한국대기환경학회지
• /
• 제8권1호
• /
• pp.7-12
• /
• 1992

This study was conducted to determine the effectiveness of silver thiosulfate(STS) in reducing $O_3$ injury to tomato plants(Lycopersicon esculentm Mill. 'Pink Glory'). Two days prior to $O_3$ fumigation, plants were given a foliar spray of STS solution at concentrations of 0, 0.2, 0.4, 0.6 mM contained with 0.05% Tween-20. STS concentrations below 0.6 mM were significantly effective in providing protection aginst $O_3$ exposure(16 h at 0.3 ppm). STS reduced leaf injury rate, defoliation of cotyledons, ethylene production and degree of epinasty induced by $O_3$ injury. STS slightly increased ethylene production in non-$O_3$-fumigated plants, but changes of chlorophyll content and transpiration rate on a whole plant basis were not observed. In $O_3$-fumigated plants, STS treatment reduced chlorophyll destruction but did not affect transpiration rate. STS treatment seemed not to affect peroxidase(POD) and superoxide dismutase (SOD) activity in non-fumigated plants but reduced increasing activity of POD by $O_3$ fumigation. However, such an effect as above was not found in SOD activity. Even though enzymatic protection effects were not confirmed, the fact that reduction of acute injury rate was attained for 16 h fumigation indicates that the phytoprotective effects of STS are not necessarily related to blocking the action of strees-induced-ethylene as an anti-ethylene agent.

• Structural Engineering and Mechanics
• /
• 제26권5호
• /
• pp.499-516
• /
• 2007

An experimental method denoted as Impulse Method is proposed as a cost-effective non-destructive technique for the on-site evaluation of concrete elastic modulus in existing structures: on the basis of Hertz's quasi-static theory of elastic impact and with the aid of a simple portable testing equipment, it makes it possible to collect series of local measurements of the elastic modulus in an easy way and in a very short time. A Hypothesis Testing procedure is developed in order to provide a statistical tool for processing the data collected by means of the Impulse Method and assessing the possible occurrence of significant variations in the elastic modulus without exceeding some prescribed error probabilities. It is based on a particular formulation of the renowned sequential probability ratio test and reveals to be optimal with respect to the error probabilities and the required number of observations, thus further improving the time-effectiveness of the Impulse Method. The results of an experimental investigation on different types of plain concrete prove the validity of the Impulse Method in estimating the unknown value of the elastic modulus and attest the effectiveness of the proposed Hypothesis Testing procedure in identifying significant variations in the elastic modulus.

• Journal of Oral Medicine and Pain
• /
• 제25권4호
• /
• pp.403-411
• /
• 2000

The authors experienced a non-painful, elevated, dome-shaped lesion on lower lip in Korean male of 22-year-old and a non-painful, elevated, dome-shape lesion on left side of mouth floor in Korean female of 36-year-old. And diagnosed the lesions as a mucocele and a ranula respectively, based on the comprehensive evaluation of data obtained from history taking, clinical and radiologic examination and histopathological findings. In these cases, the authors removed mucocele and ranula using the pulsed Nd:YAG laser with advantage of good hemostatic effect, and so we could minimize improper tissue destruction during operation. The excisional wounds of lower lip and mouth floor had a good healing process without any symptom of pain and any signs of bleeding and infection.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제5권2호
• /
• pp.241-259
• /
• 2005

The environmental problem is a main subject of the 21C and an environment destruction phenomenon by various kinds of environmental materials is reaching serious level. Nations to be classified as the environmental developed country, are born again environmental rich country. And they earn a large income by trade Every kind environmental resource in an international commercial transaction. Especially, the study that a reliability assessment method to prevent to reliability problem to be happened when the solder lead(lead-free solder), non-cd component, non-bromide component(without the polybrominated biphenyls(PBB) and polybrominated diphenyl ethers(PBDE))and hexavalent chromium(Cr VI) clearance component and mercury-free applied to electronic equipment is progressed. As the result of the study for applying of a reliability assessment technique of lead-free solder that recognized the most of urgent problem at the company, combination accelerated life test could taken by adding and appling the part of a humidity acceleration part to Eyring Model which is proposed by R.E.Thomas. The reliability assessment methods study of PWB clean environmental materials is expected to respond to a reliability elevation and environmental material regulation policy spreading all over the world by beginning form Europe.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
• /
• pp.29-29
• /
• 2010

Surface contamination and leakage current have caused operating problems. A flashover in a substation may result in destruction of an insulator or many others electrical equipment. Engineering plastics have good characteristic (light weight, good productivity and little of void) as compare with epoxy or porcelain insulators. Outdoor insulator must have resistance to contamination. However, it isn't suited to outdoor insulator because it is not hydrophobic. RTV(Room temperature vulcanizing) has a good property of hydrophobic and micro-filler. nano-filler have characteristics of obstructing exothermic reaction. In order to reduce the incidence of insulator flashover and damage, the silicon rubber contained with micro, nano-filler coating on surface of engineering plastics. In this paper, it compares tracking resistance, leakage current of the engineering plastic coated RTV with that of non-coated engineering plastic. And filled-composites performed much better than non-filled composites.

• 비파괴검사학회지
• /
• 제22권3호
• /
• pp.239-245
• /
• 2002

현재까지 다양한 토목구조물들은 여러 가지 요인에 의한 노후화와 축척된 손상에도 불구하고 별다른 조치 없이 계속해서 사용되고 있었다. 따라서, 이러한 구조물들의 효율적인 유지관리를 유해 계측관리가 중요시되었다. 이에 본 논문에서는 비파괴계측에 의해 사장교의 실시간 계측모니터링시스템을 개발하고자 하며 이를 통해 교량의 안전관리를 하고자 하였다. 계측모니터링시스템은 교량의 유지관리를 도모하고, 교량 관리의 경제적 비용을 줄이게 되며 사장교의 새로운 설계 및 분석방법을 개발하는데 중요한 데이터를 제공할 것이다.

• 약학회지
• /
• 제37권3호
• /
• pp.270-277
• /
• 1993

It is well known that lipidperoxide, formed in vivo, induced the denaturation of enzyme and destruction of cell membrane to acute injury of tissue. Aralia elata have physiological activates, the improvement of lipid metabolism, antidiabetic activity etc., which was thought to have the relationship to lipid peroxidation. The anti-lipidperoxidative effect of Aralia elata have not yet established. In this study, we examined the anti-lipidperoxidative effects of Aralia elata (Butanol fraction) on CCI$_{4}$ induced lipidperoxidation in rats, and elucidated the anti-lipidperoxidative mechanism. In rat liver homogenate intoxicated with CCI$_{4}$ (0.5 ml/100g), BuOH fraction of Aralia elata (80 mg/Kg/day) exhibited 85.41% anti-lipidperoxidative effect but in serum 69.63% inhibitory effects, respectively. In mitochondrial and microsomal fraction showed inhibition of 55.85% and 69.30%, respectively. In order to elucidate the mechanism of anti-lipidperoxidation effects of Aralia elata, enzymatic (NADPH dependent) and non-enzymatic (Ascorbic acid catalyzed) reaction, in vitro, were performed. In enzymatic reation, Aralia elata exhibited 59.43% anti-lipidperoxidation effects, but in non-enzymatic reaction exhibited 43.27% inhibition. Therefore, it is noteworthy that antioxidative power of them may mainly results from the inhibition by enzymatic reaction.