• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.1-10
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• 2000

Fungicide resistance study in Korea is still in its infancy, and most of those resistance studies are largely limited to newness of the detected resistant strains. In future, detection of fungicide-resistant strains has to be based on sensitivity distribution of pathogen populations to certain fungicides, and standard levels of certain fungicides for resistance should be determined under the basis of this data. Most of the early research on fungicide resistance in Korea has overlooked this point, and resulted in inconsistency and confusion for monitoring sensitivity shift of pathogen population among individual researchers. Fungicide resistance detected in vitro tests has to be documented in field trials by examining control efficacy against resistant and wild-type pathogen populations. Resistance detection in wife has to be correlated with lower activity in practice. Using this process, fungicide resistance will have a practical meaning. Fitness evaluation of resistant strains for survival is, in particular, of importance to determine the future stability of the resistance in the pathogen population. In fields, sensitivity change of pathogen populations should be carefully monitored with and without fungicide selection pressures to establish long-term management strategies against fungicide resistance. It is becoming an urgent task to provide information through research for designing and implementing successful counter-measures against fungicide resistance problems in Korea.

• Journal of the Korean GEO-environmental Society
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• v.13 no.10
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• pp.25-32
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• 2012

The application of electrical resistivity, which is related to charge mobility, has increased in the field of geotechnical engineering for the detection of underground cavern, faults and subsurface pollution level. The purpose of this study is to investigate the variation of electrical resistivity due to temperature change. Sand-silt mixture specimens prepared in the square freezing nylon cell are frozen in the frozen chamber. Four electrodes are attached on the four side walls of the freezing cell for the measurement of electrical resistance during temperature change. Electrical resistances of sand-silt mixtures with different degrees of saturation (0%, 2.5%, 5%, 10%, 20%, 40%, 60% and 100%) are measured as the temperature of specimens decrease from $20^{\circ}C$ to $-10^{\circ}C$. The electrical resistances determined by Ohm's law are transformed into the electrical resistivity by calibration. Experimental results show that the higher degree of saturation, the lower electrical resistivity at $20^{\circ}C$. Electrical resistivity gradually increases as the temperature decrease from $20^{\circ}C$ to $0^{\circ}C$. For the specimens with the degree of saturation of 15% or higer, electrical resistivity dramatically changes near the temperature of $0^{\circ}C$. In addition, very high electrical resistivity is observed regardless of the degree of saturation if the specimens are frozen. This study provides the fundamental information of electrical resistivity according to the soil freezing and temperature change demonstrates that electrical resistivity be a practical method for frozen soil investigation.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.11-16
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• 1974

Experiment was conducted to select the rice varieties and lines resistant to the smaller brown planthopper, Laodelphax striatellus Fallen, and study the cause of varietal resistance to the insect. The nature of varietal resistance was evaluated from the viewpoints of feeding and ovipositional preferences and antibiosis. Among the IRRI sources the varieties H 105, Muthumanikam, Vellailangalayan, Karsamba Red ASD-7. Manavari Co 22, Mudgo, PTB-18, IR 8 and IR 20 were selected as resistant sources. Among the domestic sources. only Suweon 213-1, Suweon 214 and Suweon 215 originated from the IR667 lines were resistant, and other leading varieties ail susceptible. The cause of resistance of rice to the insect seemed to be highly related with the non-feeding preference, not non-ovipositional preference. Nymphal mortality and rate of adult emergence were significantly different from the resistant and susceptible varieties. The rate of adult emergence was significantly lower in the resistant than In the susceptible varieties. The primary cause of lower adult emergence seemed to be due to the fact that the infects were suffered higher nymphal mortality in the resistant than in the susceptible varieties.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.101-120
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• 2023

Electrical resistivity survey have been widely conducted at diverse scales, from a few centimeters for laboratory tests to kilometers for field tests. It measures electrical resistance through relationship of electric potential difference and current between two electrodes penetrated on the surface of medium, and eventually quantifies electrical resistivity known as inherent properties of the medium. In field or full-scale test, it assumes the electrodes as equivalent half-sphere electrodes that have a same surface area with different electrodes for ease of calculation because the contact area between electrode and medium is small and sufficient distance between two electrodes. However, small-scale laboratory test is significantly affected by the electrode geometries (penetrated depth, height, radius of electrode and distance between electrodes), which change the equipotential surface and electric current flow. Indeed, the electrode geometries may eventually cause a difference of electrical resistivity value. This study reviews the theoretical electrical resistance derived with various electrode geometries (half-sphere, cylinder, cylindrical with half-spherical tip, cylindrical with conical tip) and verifies the developed numerical module by comparing results with the theoretical electrical resistance. The distributions of electrical resistance around electrodes and among electrodes are analyzed. In addition, it is discussed how the electrical characteristic of cylindrical electrode with conical tip widely used in field test has effect on the electric current flow.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.709-716
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• 2016

To reduce the aerodynamic drag of high speed trains, aerodynamic drag of KTX-Sancheon was analyzed in detail according to individual components. Aerodynamic drag values of the power cars (front car, rear car) and bogies are about 42.9% and 10.1% of the total aerodynamic drag, respectively. For the aerodynamic drag reduction of a power-car, a nose shape optimization was conducted using the Broyden-Fletcher-Goldfarb-Shanno optimum method. Shape change of a power car and bogie fairing adaptation are used to reduce the aerodynamic drag of a car body. The aerodynamic drag of the optimized train-set dropped by 15.0% compared to the aerodynamic drag of the KTX-Sancheon; a running resistance reduction of 12% is expected at the speed of 350km/h.

• Journal of the Korean Ceramic Society
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• v.34 no.3
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• pp.233-240
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• 1997

The Ru-based thick film resistor(TFR) for sintering at 90$0^{\circ}C$ was synthesized to prepare the LCR net-work. These compositions of pyrochlore could be prepared by decreasing the amount of PbO and increasing alumina and silica contents of glass frit. In this study, the sheet resistances of the TFTs. which sint-ered at 90$0^{\circ}C$ after printing on alumina substrate, the sheet resistances of the TFRs on inductor and capa-citor substrate and the interphase between TFR and substrate were observed. And the changes of the sheet resistance were obtained with the contents of RuO2. In case of the TFR sintered at 90$0^{\circ}C$, the sheet resis-tances on alumina substrates were in the range of 103~106$\Omega$/$\square$, but the sheet resistances of TFR on in-ductor and capacitor substrate were not obtained.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.67-75
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• 2013

In this paper, an analytical model is presented for the source/drain parasitic resistance of FinFET. The parasitic resistance is a important part of a total resistance in FinFET because of current flow through the narrow fin. The model incorporates the contribution of contact and spreading resistances considering three-dimensional current flow. The contact resistance is modeled taking into account the current flow and parallel connection of dividing parts. The spreading resistance is modeled by difference between wide and narrow and using integral. We show excellent agreement between our model and simulation which is conducted by Raphael, 3D numerical field solver. It is possible to improve the accuracy of compact model such as BSIM-CMG using the proposed model.

• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.439-445
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• 2007

SiGe integrated circuits are being used in the field of high-speed wire/wireless communications and microwave systems due to the RF/high-speed analog characteristics and the easiness in the fabrication. Reducing the resistance variation in SiGe thin film resistors results in enhancing the reliability of integrated circuits. In this paper, we investigate the causes that generate the resistance nonuniformity after the silicon-based thin film resistor was fabricated, and consider the counter plan against that. Because the Ti-B precipitate, which formed during the silicide process of the SiGe thin film resistor, gives rise to the nonuniformity of SiGe resistors, the boron ions should be implanted as many as possible. In addition, the resistance deviation increases as the size of the contact hole that interconnects the SiGe resistor and the metal line decreases. Therefore, the size of the contact hole must be enlarged in order to reduce the resistance deviation.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2003.07a
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• pp.85-85
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• 2003

본 연구는 저열량 기능성 탄수화물 소재(저항전분, 식이섬유)를 이용하여 당뇨병 환자의 혈당과 지방대사를 조절하는데 도움을 줄 수 있는 치료식을 개발하기 위해 동물실험과 임상실험을 수행하여 제품의 혈당 및 지방대사 조절, 혈당조절호르몬, 장내기능조절 효과를 검증하였다. 또한 동물실험을 통해 대장에서 염증을 일으키는 것으로 알려진 deoxycholate (DOC)를 식이무게의 2%로 첨가하고, HAS는 일반전분의 50%로 대체시켰을 때 HAS가 DOC의 염증작용에 어떠한 영향을 미치는지 살펴보아 HAS의 장기능 개선에 대한 기능성을 환인해보았고 저항전분이 혈당 및 혈액내 지질조성에 미치는 영향을 살펴보았다. 인체실험 연구결과는 저항 전분을 섭취한 군에서 체중이 유의적으로 감소하였고 비만도를 나타내는 BMI도 감소하여 개발된 선식제품의 체중감소 효과가 입증되었다. 당대사 결과는 동물실험의 경우는 저항전분을 섭취한 군에서 혈당감소를 나타내고 있으나 인체실험의 경우 선식제품 섭취 후 혈당과 인슐린의 농도가 영향을 받지 않았으며 혈액 내 지방성분은 동물실험에서는 혈액내 총지방과 중성지방이 저항전분 섭취시 감소하였고, 인체실험의 경우 저항전분 시제품 섭취 후에 혈액내 중성지방량은 약간 증가하였으나 총지방량과 총콜레스테롤량, LDL-콜레스테롤량은 감소하는 효과를 보여주었다. 또한 면역능력에 대한 지표는 저항전분 시제품 섭취 후 혈액 내 면역글로부린 G가 유의적으로 증가 하였다. 동물실험을 통한 저항전분의 장기능에 관한 연구결과는 저항전분의 한 형태인 HAS의 섭취가 대장길이와 맹장무게를 증가시키며, 맹장에서의 비피더스균의 증식을 가져와 장내 SCFA의 생산을 증가시키고, 맹장내 pH 감소를 가져오며 대장 점막에서의 PGE2의 생산을 감소시켜 장 기능개선의 효과를 나타내고 있다. 그리고 이러한 효과는 DOC섭취에 의한 부작용을 완화시키는 작용을 하였다. 또한 저항전분의 동물실험 겨로가는 혈당을 감소시키며, 혈액지방 수준을 감소시키는 효과를 나타내므로 저항전분의 섭취는 장긴\ulcorner 개선, 혈당유지, 혈액지방수준 개선의 효과가 있는 것으로 보인다.

• Geophysics and Geophysical Exploration
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• v.18 no.3
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• pp.105-114
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• 2015

A long-term resistivity monitoring system has been developed for saturated cores in room temperature and humidity condition. A 3-channel water-pump continuously drops the water onto the top of saturated core sample surrounded by shrinkable tube as well as on the paper filters of the electrodes at both sides of the core sample, by which one can monitor the resistivity changes with maintaining full saturation of the rock core for a week or longer. Monitoring the resistivity changes has been performed with 3 kinds of rock samples including biotite gneiss, andesitic tuff, and shale for 9 days using the system. Consequently, it is proposed two hypothesis that conversion speed of temperature coefficient has close relation to the thermal properties of the rock sample and that the ratio of resistance between dry and saturated conditions for a rock sample can be related to the effective porosity of the sample. The ratio between dry and saturated resistance for the three rock types are 48, 705, and 2, while effective porosity was 3.7%, 3.3%, and 13.0%, respectively.