• 제목/요약/키워드: resistance management

검색결과 1,002건 처리시간 0.028초

인공지반녹화용 멤브레인 방수 및 방근재료의 방근성능 평가 방법 제안 연구 (A Standard Test Methods of Resistance to Root Penetration for Waterproofing and Rootproofing Membrane Using Green Roof System)

  • 이정훈;선윤숙;곽규성;오상근
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2009년도 추계 학술논문 발표대회
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    • pp.141-148
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    • 2009
  • The purpose of this paper is to propose a standard test methods of resistance to root penetration for waterproofing and rootproofing membrane using green roof system. Green roof system is considered to be an important subject in construction industry for green growth project. At the same time, we have to consider the counterplan for protection the damage of waterproofing layer and concrete substrate from the penetration of plant root. But many kinds of materials for protection from root penetration are using in construction field. But the performance of those materials is not clear, and there is not test methods for the evaluation of performance. So in this paper, based on the research results of 4 institutes during four years and foreign cases, we made a standard test methods of resistance to root penetration for waterproofing and rootproofing membrane using green roof system. This test method deals with about environmental condition of laboratory, experimental facilities, kinds of plant, specimen of test, management methods, evaluation duration and documents, etc.

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전기콘센트의 사용환경과 전류값에 따른 열적특성 및 절연저항 분석 (Analysis of Thermal Characteristics and Insulation Resistance based on Usage Environment and Current Value of Electrical Socket Outlet)

  • 김경천;김두현;김성철
    • 한국안전학회지
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    • 제34권5호
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    • pp.22-30
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    • 2019
  • In 2018, overload, overcurrent, insulation aging, and a contact failure caused 659 electric fires. There is almost no failure of electrical socket outlets during their manufacturing or installation period. After several months or several years, overload or overcurrent of electrical socket outlets leads to a contact failure or short circuit which causes an electric fire. Therefore, this paper analyzed for thermal characteristics based on a current value and the change in insulation resistance along with a temperature rise caused by electrical socket outlets and the state of laboratory use in workplaces. As a results, regarding the thermal characteristics based on the current value of each installation year, a temperature increase was related to a current value, an installation year, and whether the contact unit is corroded. Insulation resistance began to decrease when a temperature increased to a certain level. With a lapse of installation year, the temperature at which insulation resistance began to decrease was lowered. This paper can be applicable for the survey data about electrical socket outlet induced fire accidents and management guidelines.

트롤선 유효마력과 어구의 적정 규모에 대한 연구 (A study on towing power of trawlers and a proper scale of trawl gears)

  • 이춘우;최규석;장용석
    • 수산해양기술연구
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    • 제57권1호
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    • pp.1-9
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    • 2021
  • Trawl fishing is a fishing method in which a large, motorized trawler tows a bag-shaped net to catch fish living at the bottom or middle layers. For a trawl gear, it is of utmost importance to select the gear size and towing speed suitable for the effective horsepower (EHP) of the trawler in the design stage. In general, the power required to move an object is proportional to the product of the object speed and resistance; therefore, there are various choices for the gear resistance and towing speed given the effective horsepower of the trawler. However, there have been few studies on the gear design of an appropriate scale for the towing speed given the effective horsepower of the trawler. In this study, the resistance and shape of three types of midwater trawl gears were analyzed using SimuTrawl, a computer simulation tool. In addition, the relationship between the propulsion force and speed of the ship was clarified when the size and effective horsepower of the trawler were determined. Finally, we suggested the relationship between the towing speed and the resistance of the gear when the trawler towed the net was investigated, and a specific method of selecting the gear size according to the towing speed.

발수가공 데이터의 분산분석 (ANOVA for Water Repellent Finish data)

  • 윤중범
    • 품질경영학회지
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    • 제16권1호
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    • pp.43-48
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    • 1988
  • Most of silicone used for water repellent finish is MHP (methyl hydrodiene polysiloxane), which is formed by hydrolysis and condensation polymerization of MHD (methyl hydrodiene dichlorosilane: Me H Si $Cl_2$). The cross-linking theory explains the water repellent mechanism of MHP. The silicone finish on fiber could improve in handle, softness, abrasion resistance, soil repellency, tear strength and crease resistance, as well as water repellency. According to using method silicone-water repellent finishing agents, could be devided into air dry type and curing type. MHP is the typical curing type of water repellent finishing agent, and this type requires the curing temperature above $150^{\circ}C$ at least. High curing temperature is the very drawback of this curing type. For this reason, there has been global interest in the lowering of its temperature. The objective of this study is to investigate merits of alkali treatment for silicone finishing by ANOVA and LSD (least significant difference).

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MPCE copolymer와 습식 폴리우레탄의 블렌드에 의한 투습방수 나일론 직물의 제반 물성변화에 관한 연구 (Property Evaluation of Breathable Blend Fabric of MPCE Copolymer and Wet Coagulated Polyurethane)

  • 이종우;채애정;배진석
    • 한국염색가공학회지
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    • 제26권4호
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    • pp.322-330
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    • 2014
  • The phospholipid-based MPCE(2-Methacryloxyethyl Phosphoryl Chlorine) copolymer was mixed with wet polyurethane for coating of nylon fabrics. The substitution rate of water in coagulation bath with DMF was changed under control of the size of formed hydrophilic microporous cell enable to manufacture excellent breathable, anti-bacterial and moisture control fabrics. Biocompatible property, vapor permeability, hydrostatic pressure, moisture management and anti-bacterial property were investigated for treated nylon fabrics. In result, increased moisture transmission rates, decreased water resistance and outstanding moisture control property could be confirmed by enhanced hydrophilicity of wet-coated nylon fabric with MPCE copolymer.

Supercapacitor용 활성탄 전극의 전기 화학적 특성 (Electrochemical Characteristics of Activated Carbon Electrode for Supercapacitor)

  • 김경민;이용욱;강안수
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2002년도 추계학술대회
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    • pp.273-277
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    • 2002
  • In the electrode fabrication of unit cell, we found that optimal the electrochemical characteristics were obtained with at 90 wt.% of activated carbon(BP-20), 5 wt.% of conducting agent(Ppy, Super P) and 5 wt.% of P(VdF-co-HFP)/PVP mixed binder. The electrochemical characteristics of unit cell with Ppy improver were as follows : 37.6 F/g of specific capacitance, 0.98 $\Omega$ of AC-ESR, 2.92 Wh/kg and 6.05 Wh/L of energy density, and 754 W/kg and 1,562 W/L of power density. It was confirmed that internal resistance were reduced due to the increase of electrical conductivity and filling density by the introduction of conductivity agent, and content of conducting agent was suitable in the range of 4~6 wt.%. According to the impedance measurement of the electrode with conductivity agent, we found that it was possible to charge rapidly by the fast steady-state current convergence due to low equivalent series resistance(AC-ESR), fast charge transfer rate at interface between electrode and electrolyte, and low RC time constant.

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폴리피롤 첨가에 의한 supercapacitor용 저 임피던스 전극 (Electrode of Low Impedance by Polypyrrole Addition for Supercapacitor)

  • 김경민;장인영;강안수
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2003년도 추계학술대회
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    • pp.343-350
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    • 2003
  • The best Ppy weight ratio was 7 wt% and the optimal electrode composition ratio was 78 : 17 : 5 wt.% of (MSP-20 : BP-20 =1 : 1), (Super P : Ppy =10 : 7) and P(VdF-co-HFP). Implantation of Ppy as the conducting agents have led to superior electrochemical characteristics because of the low of internal resistance and faradaic capacitance. The result of unit cell with Ppy 7 wt% were as follows: 28.02 Fig of specific capacitance, 1.34 Ω of DC-ESR and 0.36 Ω of AC-ESR. Unit cell showed a good stability up to 200 charge-discharge cycles, retaining 82% of their original capacity at 200 cycles. From the analysis of impedance, the electrodes with Ppy 7 wt% showed low ESR, low charge transfer resistance and quick reaction rate. It was inferred that quick charge-discharge was possible. As compared with the specific capacitance (rectangular shape) of CV, it was also concluded that the specific capacitance originated from thecompound phenomena of the faradaic capacitance by oxidation and reduction of Ppy and the non-faradaic capacitance by adsorption-desorption of activated carbon.

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가속수명시험을 이용한 은도통홀 인쇄회로기판의 신뢰성연구 (Accelerated Life Test and Data Analysis of the Silver Through Hole Printed Wiring Board)

  • 전영호;권이장
    • 품질경영학회지
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    • 제25권2호
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    • pp.15-27
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    • 1997
  • This paper describes a highly accelerated life test (HALT, USPCBT) method for rapid qualification testing of STH PWB(Silver Through Hole Printed Wiring Boards). This method was carried out to be an alternative to the present time-consuming standard 1344 hours life testing(THB). The accelerated life test conditions were $121^{\circ}C$/95%R.H. at 50V bias and without bias. Their results are compared with those observed in the standard 1344 hours life test at $40^{\circ}C$/95%R.H. at 50V bias and without bias. The studies were focused on the samples time-to-failure as well as the associated conduction and failure mechanisms. The abrupt drop of insulation resistance is due to the absorption of water vapour. And the continuous drop of insulation resistance is due to the Ag migration. The ratios of time-to-failure of HALT(USPCBT) to THB were 25 and 11 at 50V bias and without bias respectively.

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The Future of Chemical Pest Control

  • Pickett, John-A.;Woodcock, Christine-M.
    • 한국응용곤충학회지
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    • 제31권3호
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    • pp.304-313
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    • 1992
  • The agricultural industry is beset by continuing demands to decrease the use of pest control agents which employ toxic modes of action. Although there are real problems of pesticide resistance, and sometimes overuse or redistribution in the environment, much criticism results from a lack of appreciation of how small is the risk involved. Whatever the background reasons, research and development for pesticide alternatives, particularly within Integrated Pest Management systems, is clearly of high priority. Currently available approaches, including use of natural products and molecular biology, are often regarded with naive optimism and require critical appraisal. For the future, methods of pest control based on chemicals with non-toxic modes of action (e.g. pheromones) continue to offer promise but, for widespread use, will require their integration with biological agents and development by means of plant molecular biology.

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Predictors and management of intravenous immunoglobulin-resistant Kawasaki disease

  • Song, Min Seob
    • Clinical and Experimental Pediatrics
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    • 제62권4호
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    • pp.119-123
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    • 2019
  • Kawasaki disease (KD) is a systemic vasculitis that mainly affects younger children. Intravenous immunoglobulin (IVIG) resistant cases are at increasing risk for coronary artery complications. The strategy on prediction of potential nonresponders and treatment of IVIG-resistant patients is now controversial. In this review the definition and predictors of IVIG-resistant KD and current evidence to guide management are discussed.