• Geophysics and Geophysical Exploration
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• 제10권4호
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• pp.322-331
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• 2007

In this study, electrical resistivity tomography (ERT) were conducted to find the mineralized zone at the Geumpung mine in Dojeon-ri, Susan-myeon, Jecheon-si, Chungcheongbuk-do. The deviation of the inclined borehole was measured to obtain the exact positions of the electrodes for correcting apparent resistivity values from ERT. Geophysical loggings such as resistivity and natural gamma were conducted to obtain the properties of the material near the borehole. Measurements of the physical properties of the cores, such as porosity, water content, density, susceptibility, resistivity were performed to analyze the correlation between physical properties and resistivity. Grade analysis for core sample was also conducted to identify relationship between grade and resistivity. Rock property analysis shows that the resistivity is more dominated by susceptibility and grade than by porosity and water content in the mineralized zone. The results of ERT are well consistent with geophysical logging data and geologic column. So ERT is powerful method to identify conductive mineralized zone.

• Journal of Korean Society of Coastal and Ocean Engineers
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• 제24권1호
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• pp.26-35
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• 2012

Until now, study on the hydraulic resistance characteristics of the ground at the river and the ocean current has been focused on the behavior under uni-directional flow without the direction change of flow. However, recent research result shows that scour rate which were measured under the bi-directional flow was much higher than those measured under uni-directional flow for both fine grained and coarse soil. Since the direction of inflow and return flow at the shore, where the structure will be constructed, is not always $180^{\circ}$, effect of the incidence angle on the hydraulic resistance capacity of the ground should be examined. Using the improved EFA which can consider the direction change of flow, hydraulic resistance capacities of the artificially composed clayey fine grained soil and clayey sandy soil under $0^{\circ}$, $90^{\circ}$, $135^{\circ}$, $180^{\circ}$ flow angle of incidence were assessed. Test result shows that hydraulic resistance capacity decreases and scour rate increase with the increase of the incidence angle between inflow and return flow. For the low consolidation pressure condition, hydraulic resistance capacity of the fine grained soil decreases rapidly. While the hydraulic resistance capacity of the coarse grained soil decreases more rapidly than fine grained soil under high consolidation pressure. Eventually since the larger the incidence angle between inflow and return flow, the larger the scour rate. Hydraulic resistance capacity under bi-directional flow($0^{\circ}{\longleftrightarrow}180^{\circ}$) should be examined for the design purpose.

• Journal of Sensor Science and Technology
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• 제9권2호
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• pp.96-105
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• 2000

Fiber optic TR-EFPI(total reflected extrtinsic Fabry-Perot interferometric) sensor was developed to measure the strain of structures, such as building, bridge, aircraft, etc. It has been difficult to distinguish the increase and decrease of the strain from the conventional fiber optic EFPI sensor because their signals only have a sinusoidal wave pattern related to the change of strain. Also, the absolute strain could not be measured by the simple fiber optic EFPI sensor. In this study, in order to measure the magnitude of strain with the direction of strain, the fiber optic sensor was simply constructed with the total reflected EFPI sensor probe. This probe was manufactured with a single mode fiber and a mirror coated fiber in a silica glass capillary tube. The output signal of this fiber optic TR-EFPT sensor can give the information about the magnitude and the direction of strain. The loading-unloading test was performed by the universal testing machine with alluminum beam specimen to compare the strain from fiber optic TR-EFPI sensor with the value from electrical strain gauge. In the result of this experiment. the strain from fiber optic TR-EFPI sensor had a good agreement with the values from the electrical strain gauge.

• Journal of the Korean Geotechnical Society
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• 제25권2호
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• pp.45-54
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• 2009

The electrical characteristics of soils have been used for investigating soil properties. The purpose of this study is the development and application of the electrical resistivity cone probe (ERCP) for the evelation of the porosity in the field with high precision. The shape of the probe tip is a cone shape to minimize the disturbance during penetration. In addition, the four terminal pair configuration is adopted to minimize the electrical interference. The electrical resistances are continuously measured during penetration of the ERCP using penetration rigs with 0.33 mm/sec penetration rate at Incheon and Busan sites. With the measured resistance profile and electrical resisivity of electrolyte of undisturbed samples, soil porosity profiles are obtained by using Archie's law. The empirical coefficients for the Archie's law are obtained based on the electrolyte extracted from the undisturbed samples. The estimated porosity profiles show similar trends to those of in-situ penetration tests such as SPT, CPT, and DMT. This study suggests that the ERCP may be an effective tool for the porosity estimation in the field with minimum disturbance.

• Resources Recycling
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• 제15권2호
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• pp.10-17
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• 2006

The purpose of this study was to evaluate the effects of blast-furnace slag on strength development and durability of latex-modified concrete (LMC) and ordinary portland cement concrete as slag contents. Main experimental variables were performed latex contents (0%, 10%, 15%) and slag contents (0%, 30%). The compressive and flexural strengths, chloride-ion rapid permeability and chemical attacks resistance were measured to analyze the characteristic of the developed LMC and BS-LMC(latex-modified concrete added blast-furnace slag) on hardened concrete. The test results showed that compressive and flexural strength of BS-LMC increased as the slag contents increased from 0% to 30% at the long term of curing. It considers blast furnace slag used when latex content was up to 10%. The permeability resistance of BS-LMC(latex 10%, blast 30%) was extremely good at the curing time 90 days. Also. the effects of added blast furnace slag on OPC and LMC were increased on the permeability and chemical attacks resistance.

• Resources Recycling
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• 제17권5호
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• pp.19-27
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• 2008

In this study, the porosity and electrical resistivity of the formed coke produced by sintering the mixture of domestic anthracite and phenolic resin were mainly investigated, when the effect of the amount of binder, the hydration temperature and time, the hardening temperature and time, sintering temperature and time, the particle size of anthracite, the grade of anthracite, and the mixing ratio of phenolic resin on the physical properties of the coke were studied. As a result, It was found that the electrical resistivity and porosity of the formed coke are varied in the range of $0.3\sim1.2\Omega{\cdot}cm$ of $10\sim30%$, respectively, in accordance with the variation of factors.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.85-85
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• 2011

RF magnetron co-sputtering을 이용하여 RF power 및 공정 압력에 따라 GZO 및 IGZO 박막을 유리기판 위에 제작하고 투명전극으로 구조적, 광학적, 전기적 특성을 조사하였다. 박막 증착 조건의 초기 압력은 $1.0{\times}10^{-6}Torr$, 증착온도는 상온으로 고정하였으며 기판은 Corning 1737 유리기판을 사용하였다. 소결된 타겟으로 ZnO, $In_2O_3$ 및 $Ga_2O_3$을 이용하였으며, 각각의 타겟은 독립 된 RF파워를 변화시키며 투명전극의 성분비를 조절하였으며, 증착 압력은 10 m에서 100 mTorr까지, 기판과의 거리는 25 mm에서 65 mm까지 변화시키며 박막을 제작하였다. 유리기판 위에 불순물이 첨가된 모든 ZnO 박막에서 (002) 면의 우선배향성이 관찰되었고, 3.4eV에서 3.5eV 정도의 광학적 밴드갭을 가지며 80% 이상의 투과율을 나타내었다. GZO 박막의 경우 증착 조건에 따라 투명전극에 요구되는 $5*10^{-3}{\Omega}-cm$ 이하의 전기적특성을 가짐을 보였으며, gallium 성분이 0%에서 6%로 증가함에 따라 3.3eV에서 3.5eV로 blue-shift하였으며, 비저항은 0.02에서 $0.005{\Omega}cm$로 낮아졌으며 이동도는 $4.7cm^2V^{-1}s^{-1}$에서 $2.7cm^2V^{-1}s^{-1}$로 보이며 GZO 물질이 투명전극으로서 기존의 ITO 물질 대체 가능성을 확인하였다. IGZO 박막은 In과 Ga의 함량에 따라 저항률의 변화가 크게 나타났으며, In의 함량이 많을수록 이동도, 캐리어 농도의 증가로 저항률은 감소하였다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2005년도 공동학술대회 논문집
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• pp.65-70
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• 2005

A low resistivity zone is found in many places such as a fractured fault zone, weathered zone and aquifer. The electrical resistivity is influenced mainly by pore fluid as well as the clay mineral types and contents, Hence, it is very important to understand the relationship between the electrical resistivity and clay contents associated with the low resistivity zone for geotechnical applications such as civil engineering. This study examines the characteristics of clay mineral types and contents to electrical resistivity through sample measurements, and proposes an expression relating the resistivity and clay content. The electrical resistivity is measured for an artificial agar specimen with clay minerals instead of a natural rock. The clay minerals used are Kaolinite and Montmorillonite. Montmorillonite shows remarkably lower resistivity than Kaolinite, although its clay content is fewer than that of Kaolinite. Also, the proposed expression shows a good correlation coefficient as high as 0.89 or more in all clay minerals.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제34권1호
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• pp.14-22
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• 1989

Rice varieties showing different degree of resistance were compared with their yield losses due to the damage of sheath blight disease in field condition through 1985 to 1986. Gayabyeo showed the lowest value of disease severity among 5 varieties tested in 1985 and 8 in 1986. and Taebaekbyeo, Kwanakbyeo and Labelle showed higher value of disease severity under the condition of artificial or natural disease inoculation. Grain yield of Gayabyeo, a moderate resistant rice variety, was reduced by 0.3 to 5％ in the rate due to sheath blight disease damage and Taebaekbyeo. a susceptible variety. showed the highest in the rate of yield loss, 6.8 to 25.8 ％. The matured grain rate and 1000-grain weight of the matured tiller were decreased when the developing disease lesion reached to the flag leaf, and then panicle weight was decreased more than 25 ％ compared with panicle of healthy culm. In conclusion, Gayabyeo showed the lower rate of yield loss because of slow development of disease to the upper leaves after initial disease occurence on the lower parts of rice plants.

• Journal of the Korean Applied Science and Technology
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• 제38권1호
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• pp.271-279
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• 2021

The purpose of this study was to investigate the effects of maximum and endurance resistance exercises on total work, blood viscosity, and erythrocyte volume ratio. The study subjects were selected as 15 men in their twenties with 12 months or more of resistance exercise experience, and the bench press 1RM was measured before the experiment, and the experiment for each condition was cross-allocated at intervals of one week, and the maximum repetition was performed in 6 sets. As a result, the total amount of exercise showed that the muscular endurance strength was higher than that of the maximum muscular strength (p<.001), and the blood viscosity and erythrocyte volume ratio were higher after exercise than before (p<.01) regardless of the total exercise amount. In summary, it was found that blood viscosity was not affected by exercise intensity and amount of exercise, and increased with one-time resistance exercise. This is clinically significant in constructing a resistance exercise program, and it is considered to be a reference material in creating an exercise program for clinical patients related to vascular disease.