• 한국산림과학회지
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• 제48권1호
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• pp.59-63
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• 1980

삽목후(揷木後) 발근(発根)하기 까지에 있어 발근용역(発根容易)한 수종(樹種)과 곤란(困難)한 수종(樹種)간의 통수저항(通水抵抗)이 어떻게 변화(变化)하고 있는가를 삽수(揷穗)의 부의별(部位別)로 측정(測定)하였다. 1. 삽수(揷穗)의 전체(全体) 저항(抵抗)(RT)은 수종(樹種)에 의해 크게 달랐으며 발근용역(発根容易)한 수종(樹種) (Euonymus japonica. Viburnum Awabuki)에서는 저항(抵抗)의 증대(増大)가 완만하였지만, 발근곤란(発根困難)한 수종(樹種)(Quercus glauca, Pasania edulis, Rhaphiolepis umbellata Mak var integerreima)에 있어서는 삽목후(揷木後) 시일(時日)이 지남에 따라 급격(急激)히 증가하였다. 2. 잎을 제거한 경전체(茎全体)의 저항(抵抗)(RS)은 발근용역(発根容易)한 수종(樹種)에 있어서는 삽목후(揷木後) 시일(時日)이 지남에 따라 급격(急激)히 증가하였으며 발근곤란(発根困難)한 수종(樹種)의 경전체(茎全体)의 저항(抵抗) (RS)은 거의 증가하지 않았다. 3. 절단면부위(切断面部位)의 경의 저항(抵抗)(RC)은 발근용역(発根容易)한 수종(樹種)에서는 RC는 급격(急激)히 증가하고 있지만 발근곤란(発根困難)한 수종(樹種)에서는 거의 증가(増加)하지 않았고, 잎을 제거한 경전체(茎全体)의 저항(抵抗)(RS) 절단면부위(切断面部位)의 경(茎)의 저항(抵抗)(RC)의 변화(变化)에 기인하고 있었다. 4. 발근곤란(発根困難)한 수종(樹種)에 있어서는 엽(葉)의 엽액부(葉腋部)의 저항(抵抗)(RL)이 가장 컸으며, 삽수(揷穗)의 전체(全体) 저항(抵抗)(RT)의 대부분(大部分)을 RL가 점하고 있었다.

• 한국지반공학회논문집
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• 제36권12호
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• pp.87-97
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• 2020

최근에는 블록식 방파제의 단점을 보완하고 경제적인 설계가 가능한 타이셀소파블록에 대한 관심이 증가하고 있다. 타이셀소파블록은 각 블록을 말뚝으로 결속한 구조체로 활동저항성이 매우 우수한 특징을 가지고 있다. 본 연구에서는 실내모형실험을 통해 말뚝의 관입으로 인한 타이셀소파블록의 수평저항력 증가를 명확하게 확인할 수 있었다. 그리고 말뚝의 수평저항력은 블록의 상재하중에 상관없이 거의 일정하게 나타났다. 말뚝이 분담하는 수평저항력은 블록과 블록사이의 마찰이 담당하는 수평저항력 증감에 따라 변화하였다. 말뚝을 두개 관입시킨 실험에서는 싱글말뚝을 사용한 경우 보다 전반적으로 수평저항력이 크게 나타났으나 말뚝의 저항 거동은 다르게 나타났다.

• Safety and Health at Work
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• 제11권4호
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• pp.405-417
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• 2020

Background: Electrical socket outlets are used continuously until a failure occurs because they have no indication of manufacturing date or exchange specifications. For this reason, 659 electrical fires related to electrical socket outlets broke out in the Republic of Korea at 2018 only, an increase year on year. To reduce electrical fires from electrical socket outlets, it is necessary to perform an accelerated test and analyze the thermal, insulation resistance, and material properties of electrical socket outlets by installation years. Methods: Thermal characteristics were investigated by measured the temperature increase of electrical socket outlets classified according to year with variation of the current level. Insulation resistance characteristics was measured according to temperature for an electrical socket outlets by their years of use. Finally, to investigate the thermal and insulation resistance characteristics in relation to outlet aging, this study analyzed electrical socket outlets' conductor surface and content, insulator weight, and thermal deformation temperature. Results: Analysis showed, regarding the thermal characteristics, that electrical socket outlet temperature rose when the current value increased. Moreover, the longer the time that had elapsed since an accelerated test and installation, the higher the electrical socket outlet temperature was. With respect to the insulation resistance properties, the accelerated test (30 years) showed that insulation resistance decreased from 110 ℃. In relation to the installation year (30 years), insulation resistance decreased from 70 ℃, which is as much as 40 ℃ lower than the result found by the accelerated test. Regarding the material properties, the longer the elapsed time since installation, the rougher the surface of conductor contact point was, and cracks increased. Conclusion: The 30-year-old electrical socket outlet exceeded the allowable temperature which is 65 ℃ of the electrical contacts at 10 A, and the insulation resistance began to decrease at 70 ℃. It is necessary to manage electrical socket outlets that have been installed for a long time.

• Tribology and Lubricants
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• 제16권4호
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• pp.253-258
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• 2000

Frictional behavior of wire electric discharge machined surfaces of spheroidized annealed STDll steel was investigated. The surfaces were produced with a various series of finish cuts where pulse energy was reduced with increase in the number of finish cuts. Roughness and micro-hardness of the surfaces were also measured. It is observed that the increase in the number of finish cuts produces the surface exhibiting lower frictional resistance followed by higher resistance after considerable wear. Effects of finish cuts on the friction characteristics are discussed with the aid of roughness and micro-hardness of the surfaces.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.867-875
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• 2014

Planing crafts were specifically designed to achieve relatively high speeds on the water. When a planing craft is running at high speed, dynamic pressure on the bottom makes the boat rise on the surface of the water. This reduces the area of the sinking surface of the boat to increase air resistance. Air resistance means the resistance that occurs when the hull and deck house over the surface of the water come in contact with the air current. In this paper, we carried out a CFD numerical analysis to find optimal deck houses that decreased air-resistance on the water when planing crafts are running at high speed. We finally developed the deck house shape of high-speed planing crafts that optimally decreased air resistance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.94-97
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• 1997

We investigated the sheet resistance properties of tungsten nitride thin films deposited by RF and DC sputtering system. It deposited at various conditions that determine the sheet resistance. The properties of the sheet resistance of these films were measured under various conditions. Sheet resistance analysed under the flow rate of the argon gas and contents of nitrogen from nitrogen-argon gas mixtures. We found that these sheet resistance were largely depend on the temperature of substrate, gas flow rate and RF power. Very high and low sheet resistance of tungsten films obtained by DC sputtering. As the increase of contents of nitrogen gas obtained from nitrogen-argon gas mixture, tungsten nitride thin films deposited by the reactive DC sputtering and the sheet resistance of these films were increased.

• Journal of Plant Biotechnology
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• 제4권1호
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• pp.1-6
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• 2002

Plants have developed a sophisticated battery of defence responses to protect themselves against attempted pathogen ingress. Manipulation of these defence mechanisms may provide significant opportunities for crop improvement. While plant resistance genes have had a long service history in plant breeding, they possess significant limitations. Recent advances are now providing significant insights into strategies designed to increase the field durability of this class of genes. Hypersensitive cell death is a common feature underlying the deployment of plant defence responses against biographic pathogens. In contrast, necrotrophic pathogens actively kill plant cells. Recently, transgenic plants have been developed that either promote or suppress cell death, providing resistance against either biotrophic or necrotrophic pathogens respectively. Methyl-jasmonate is a key signalling molecule in the establishment of resistance against some fungal pathogens. Increasing the concentration of this molecule in plant cells has been shown to increase resistance against Botrytis cineria, without significantly imparting plant growth or development. Due to the multifarious infection strategies employed by plant pathogens, how-ever, it is unlikely a single commercial product will prove a panacea for global disease control. Future stategies will more likely entail an integrated disease management approach.

• Journal of Welding and Joining
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• 제32권2호
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• pp.70-75
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• 2014

In automotive industry, applying of Mg alloy to autobody has been issued recently as a light metal. But poor resistance spot weldability of Mg alloy is blocking commercialization. So studies on improving resistance spot weldability of Mg alloy is increasing continuously. For reduce loss of heat input during welding, inverter DC power source is considered because of short rise time to target welding current. But rapid rising of welding current can increase temperature rapidly in nugget and oxide film between electrode and base metal, and that causes generating expulsion on low welding current range. In this study, for increase optimum welding current range and prevent generating expulsion, applicate various types of welding current waveform controls during resistance spot welding. For analysis effects of each current waveform control, acceptable welding current regions according to electrode force and welding time is determined and lobe diagram is derived. In result, pre heat is proposed as optimum type of welding current waveform control.

• Corrosion Science and Technology
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• 제20권4호
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• pp.196-203
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• 2021

To improve corrosion resistance and reduce the hydrogen uptake of 22MnB5, up to 5% Mg was added to the AlSi coating of 22MnB5. After hot-stamping and electrocoating were done on the metallic-coated specimen, the surface characteristics of the steel, hydrogen uptake content, and corrosion resistance were examined by transmittance electron microscopy, thermal desorption spectrometry, cyclic corrosion testing, and electrochemical impedance spectroscopy. Mg was investigated as MgO on the surface layer after hot-stamping while it existed as Mg₂Si before hot-stamping. The total hydrogen content of 22MnB5 was decreased along with the Mg content. However, there was no difference at 0.2 wt% or more. When a small amount of Mg was added, the coating corrosion resistance was decreased, but when it was added at around 1.0 wt%, the greatest corrosion resistance increase was seen. However, when 3 wt% or more was added excessively, the corrosion resistance was decreased. MgO on the surface was considered to suppress H uptake by the AlSi melting solution and increase the barrier effect of the coating.

• PNF and Movement
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• 제11권2호
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• pp.57-65
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• 2013

Purpose : This purpose of this study was to investigate the effects of elastic band resistance exercise program in the falls prevention of elderly women. Methods : The subjects of this study, 46 people elderly women who participated in the exercise program of Jeollanamdo Y elderly welfare center were chosen as subjects and use the elastic band resistance exercise program for 12 weeks. Results : There was a significant increase on the physical function and fall efficacy of all the subjects in the experimental group and the control one after the experiment. Furthermore, the experimental group showed more meaningful improvement than the control one. Conclusion : Falls Efficacy of the experimental group before the experiment, after the changes in difference was noted. More results from the 12 weeks of using the elastic band resistance exercise program to increase the efficacy of body functions (power of lower extremity, muscle endurance, flexibility, balance, and agility), and falls efficacy of elderly women is considered as an effective fall prevention exercise program.