• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.378-387
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• 2010

We present the results of laboratory measurement of porosity and electrical resistivity for the samples collected near marine hydrothermal deposit to provide fundamental perspective of physical properties for future electromagnetic survey. The rock cores are sampled from the host rock, pumice, hydrothermal altered zone, and chimney. These samples are featured as easily brittle, rough surface with large pores, having components easily solvable in the water. We suggest systematic approach for measuring weights, volumes of core samples to calculate density and porosity. Measurements reveal that the resistivities of black host rock, gray host rock, pumice and chimney are 102, 39, 11, 0.1 ohm-m, respectively, when the core samples are saturated with saline water of $32,000\;{\mu}S$/cm (0.5 ohm-m) at temperature of $2.5^{\circ}C$ and these correspond to the factors of 5 for sea water, 110 for pumice and 390~1020 for host rocks with respect to the resistivity of chimney. We also confirm that resistivity of rock samples saturated with water decrease with temperature linearly over the temperature range of $20{\sim}80^{\circ}C$.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.5
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• pp.356-361
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• 2005

A temperature-compensating double fiber Bragg grating(FBG) sensor having two different FBGs in one fiber line was proposed for real time measurement of mechanical normal strain in structures. Measurement of mechanical strains of the aluminum beam surface by the double FBG sensor was performed under various thermal conditions, and the results were compared with those of electrical resistance strain gage. The FBG sensor fabricated in this study was able to measure accurately the mechanical strains without containing any thermal strain component.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.1 no.1
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• pp.107-114
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• 1998

Purpose: The purpose of our study is to provide useful information for me-asurement methods of childhood obesity and to provide clinical significance of bioelectrical impedance analysis. Methods: We measured height, weight, waist to hip ratio, skinfold thickness and bioelectrical impedance from 206 elementary students in Kwangju from May to July 1997. Results: In males; 1) There were statistically high correlations between tri-ceps skinfold thickness and body mass index (BMI), percentage of body fat (%BF), weight, Rohler index (RI), total fat weight (TFW), waist to hip (W/H) ratio, height, lean body mass (LBM) (all, p<0.001). 2) There were statistically high correlations between subscapular skinfold thickness and BMI, RI, weig-ht, %BF, TBW (all, p<0.001). 3) There were statistically high correlations between %BF and BMI, triceps skinfold thickness, RI, TFW, subscapular skinfold thickness, weight (all, p<0.001). In females; 4) There were statistically high correlations between triceps skinfold thickness and BMI, weight, LBM, height, %BF (all, p<0.001). 5) There were statistically significant correlations between subscapular skinfold thickness and BMI, weight, LBM, RI, height. 6) There were statistically high correlations between percentage of body fat and BMI, RI, triceps skinfold thickness. The percentage of body fat according to the bioelectrical impedance analysis highly correlated with that calculated by skinfold thickness in males (r＝0.57, p<0.01) and in females (r＝0.30, p<0.01). Conclusion: The results of our study suggests that bioelectrical impedance analysis is a useful method of estimating body fat in the childhood obesity.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.65-71
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• 2019

Conventional methods of measuring ground resistance and ground resistance field measurement are used to measure voltage drop according to the resistance value of the site by applying current by installing a constant interval of measurement electrode. If the stratified structure of the site site is unique, errors in boundary conditions will occur in the event of back acid and the analysis of the critical ground resistance in the ground design will show much difference from simulation. This study utilizes the Arduino module and smart ground measurement technology in the convergent information and communication environment to develop a reliable smart land resistance measuring device even if the top layer of land is unique, to analyze the land resistance and accumulate data to predict the change in the age of the land. Considering the topographical characteristics of the site, we propose a ground resistance measuring device and its method of measuring ground resistance so that the auxiliary electrode can be installed by correctly positioning the angle and distance in measuring ground resistance. Not only is ground resistance value obtained through electrodes installed to allow accurate ground resistance values to be selected, but it can also be used as a useful material for installing electrical facilities in similar areas. Moreover, by utilizing reliable data and analyzing the large sections of the site, a precise analysis of the site, which is important in ground design as well as construction cost, is expected to be used much in ground facility design such as potential rise.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.67-71
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• 1984

These experiments were conducted at field and green house in order to screen the resistant sesame varieties to Phytopthora nicotianae var. parasitica. and to ascertain the infection conditions of Corynespora cassiicola at different temperatures, soil moistures and leaf stages. Most of varieties studied in this experiment were very susceptible to the Phytopthora blight. Orotall, Suweon 7, Suweon 27 and Jochiweon were resistant to the disease. PI280795 and IS103 showed a tendency to be morderately resistant. The infected areas by Corynespora leaf blight were 15% in Kwangeui and 25% in Kimpo variety at high temperature condition of 3$0^{\circ}C$, respectively. The infection areas were 50% in Kwangeui and 70% in Kimpo variety at low temperature condition of 17$^{\circ}C$. These results indicate that the development of the leaf blight was highly increased at low temperature. The infection areas by the Corynespora were 55% in Kwangeui and 80% in Kimpo at wet soil moisture condition, and 10% in Kwageui and 15% in Kimpo at dry condition, respectively. The infection of the leaf blight was highly increased at 6 leaf stage and flowering date compared to at 10 and 20 leaf stages. The infection ratios were 20% at 6 leaf stage and 52.5% at flowering date, respectively.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.170-175
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• 2010

A total of 24 isolates of S. homoeocarpa were isolated from 16 golf courses in Korea. Chemical resistance of 24 isolates was determined by in vitro fungal growth on fungicide-amended media with thiophanatemethyl (Benzimidazole fungicide family), tebuconazole (demethylation inhibitor fungicide family: DMI), and iprodione (dicarboximide fungicide family). Results indicated that 83.3% of 24 isolates were resistant to iprodione, 62.5% resistant to thiophanate-methyl and 0% resistant to tebuconazale. The dual resistance of iprodione and thiophanate-methyl was 58.3.%. Occurrence rate of fungicide resistance of thiophanate-methyl and iprodione had no relation to turfgrass varieties and isolated locations of pathogen. In the filed test, procymidone, boscalid, and fluquinconazole+pyrimethanil effectively controlled the dollar spot of creeping bentgrass.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.113-117
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• 1978

An attempt was made to establish a mass-screening technique for resistance to purple seed stain .disease in soybean. Seeds sterilized in 1 : 10000 'mercuric chloride for 1 minute and transffered to Petridishes containing 20ml water agar plus 50ppm of the sodium salt of 2,4-D were inoculated by placing a small agar cube containing fungal mycelium on the seed coat of each seed. A positive correlation between natural infection of purple seed :stain and purple discoloration by seed inoculation technique was highly significant and by this technique, some native soybean collections and introduced varieties were tested for resistance to the disease. Most of the soybean varieties tested were susceptible except for the varieties Hill, Harosoy and Sac, resistant comparatively.

• Journal of Biomedical Engineering Research
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• v.22 no.6
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• pp.503-510
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• 2001

In this paper. we describe a 32-channel bioimpedance measurement system It consists of 32 independent constant current sources of 50 kHz sinusoid. The amplitude of each current source can be adjusted using a 12-bit MDAC. After we applied a pattern of injection currents through 32 current injection electrodes. we measured induced boundary voltages using a variable-gain narrow-band instrumentation amplifier. a Phase-sensitive demodulator. and a 12-bit ADC. The system is interfaced to a PC for the control and data acquisition. We used the system to detect anomalies with different resistivity values in a saline Phantom with 290mm diameter The accuracy of the developed system was estimated as 2.42% and we found that anomalies larger than 8mm in diameter can be detected. We Plan to improve the accuracy by using a digital oscillator improved current sources by feedback control, Phase-sensitive A/D conversion. etc. to detect anomalies smaller than 1mm in diameter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.336-337
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• 2007

현재 투명전극의 재료로 ITO, ZnO, $SnO_2$등의 재료가 주로 이용되며, 낮은 저항률을 장점으로 가지는 ITO 박막이 가장 널리 이용되고 있으나, 가격이 비싸다는 단점을 가지고 있다. 이 밖에도 ITO 박막보다 가격이 저렴한 ZnO박막에 대한 연구가 많이 진행되고 있으나, 고온에서의 열적 불안정성 등의 문제로 상용화되지는 못하고 있다. 그러나 $SnO_2$ 박막은 ITO와 ZnO 박막보다 저항률이 다소 높지만, 우수한 열적, 화학적 안정성과 저렴한 가격으로 ITO 박막을 대체할 투명전도막 재료로 주목받고 있다. 본 연구에서는 $SnO_2$박막의 저항률 향상을 위하여 ATO(Antimony doped Tin Oxide) 박막을 RF Magnetron Sputtering 법으로 Coming glass위에 증착하였으며, 박막 증착시 산소 유량의 변화가 ATO 박막의 구조적, 전기적 그리고 광학적 특성에 미치는 효과를 연구하였다. 본 실험에서는 동작압력을 10 mTorr, RF power를 250W로 고정하고 $O_2$ 유량을 부분적으로 변화시키면서 증착되어진 ATO 박막을 분석한 결과 Ar:$O_2$의 비가 90:10일 때 최적의 가스비율로써 우수한 구조적, 전기적 그리고 광학적 특성을 보임을 확인하였다.