• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.79-81
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• 2007

• Journal of the Korean Society of Groundwater Environment
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• v.2 no.2
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• pp.78-84
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• 1995

In 1983, 83 Wenner vertical electrical sounding(VES)s and 22 pumping tests had been carried out by Korea Agricultural Development Corporation(KADC) in Guam Myun, Yeoju Gun, Kyounggi Province. Also, 10 boreholes had been constructed in the area. Using these data electrical and hydraulic properties of aquifer in the Ganam area are investigated in this study. Assuming that the underground is 1-D, VES data are analyzed. Data analysis shows that the subsurface of study area can be interpreted as 4-layer structure and the 3rd layer which is regarded as aquifer has mean thickness of 10 m and mean resistivity of 506 ohm-m and rests on resistive bedrock. Under the circumstances, as most part of electric current flows parallel to the bedding, longitudinal unit conductance is an important parameter controlling VES curves and very closely correlates with transmissivity of aquifer in the study area. Thus, relation between longitudinal unit conductance and transmissivity is investigated in this study. Since resistivity and thickness of each layer are obtained from interpretation of VES data, the relations between transmissivity and resistivity, and between hydraulic conductivity and resistivity are also studied. Studies of such relations show that longitudinal conductance is proportional to transmissivity, and resistivity is inversely proportional to transmissivity and hydraulic conductivity.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.133-136
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• 2005

스퍼터링 공정으로 Al이 $2\%$ 함유된 ZnO 박막을 PET에 증착하여 김서림 제거용 투명발열체를 제작하였다. 증착된 투명발열체는 $5\;{\times}\;10^{-3}{\Omega}\;cm$ 의 비저항과 $80\%$ 이상의 가시광 투과도를 나타내었고, 조도는 12.5nm로 양호하였다. 투명발열체의 비저항, 가시광 투과도, 그리고 조도는 각각 Hall 계수 측정장비, IR-VIS-UV spectrophotometer, 그리고 AFM을 이용하여 측정하였다. 증착된 투명발열체에 12V의 전압을 인가하였을 때, 표면의 온도는 평균적으로 1분에 약 $10^{\circ}C$ 증가하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.444-444
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• 2012

본 연구에서는 흑연(graphite)과 티타늄(titanum; Ti) 타겟이 양쪽에 부착되어 있는 비대칭 마그네트론 스퍼터링 장치를 이용하여 Ti가 도핑되어진 탄소(a-C:Ti) 박막을 증착하였다. 흑연 타겟의 파워는 고정하고 Ti 타겟 파워를 증가시켜 탄소 박막내에 Ti의 함량을 증가시켰으며, Ti 금속 함량에 따른 탄소박막의 경도와 마찰계수, 표면의 거칠기, 접촉각 등의 물리적 특성과 비저항 등 전기적 특성을 고찰하였으며, XPS와 라만등을 이용하여 a-C:Ti 박막의 구조적 특성을 고찰하여 Ti 금속 함량에 따른 구조적 특성과 물리적 특성, 전기적 특성과의 관계를 규명하였다.

• Journal of the Korean Vacuum Society
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• v.4 no.1
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• pp.85-90
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• 1995

본 연구에서는 투명 전극으로의 응용을 목적으로 PECVD법에 의해 증착된 B이 첨가된 ZnO 박막의 전기 및 광학적 특성을 살펴보았다. B을 첨가하지 않은 ZnO 박막은 비저항이 수 $\Omega$-cm 정도의 값을 가지고 있었으며 시간에 따른 비저항의 변화가 컸으나, 2% B2H6을 5-16sccm의 유량범위에서 첨가한 경우에는 5-9X10-2 $\Omega$-cm의 비저항을 가지고 시간 경과에 따른 비저항의 변화가 아주 작은 ZnO 박막을 얻을 수 있었다. Van der Pauw법에 의한 Hall 계수의 측정 결과에 의하면, B을 첨가하지 않은 ZnO 박막의 전자 농도는 1017/㎤정도였으나 B을 첨가함으로써 최고 1020/㎤까지 증가하였다. 그러나 B이 첨가되기 전에는 박막의 전하 나르게 이동도가 $4extrm{cm}^2$/V.sec 이었으나, B참가에 의해 $0.7\textrm{cm}^2$/V.sec 이하로 감소하였다. B을 첨가한 경우와 첨가하지 않은 경우의 ZnO 박막은 모두 가시광성영역에서 90%이상의 광투과율을 가지고 있었으며, B을 첨가한 경우는 전자농도가 증가함에 따라 광학적 밴드 갭이 3.3eV로부터 3.55eV로 증가하는 거동을 보였다.

• Nuclear Engineering and Technology
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• v.1 no.2
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• pp.91-101
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• 1969

Resistivity changes of n-type float-zone silicon crystals with 6.4$\times$10$^{14}$ to 1.25$\times$10$^{17}$ phosphorus atoms/㎤ due to irradiation by (1) 1 MeV electrons, (2) two types of research reactors, and (3) $Co^{60}$ ${\gamma}$-ray sources were investigated. The results were analyzed on the basis of a simple exponential formula derived by Buehler. While the formula gave a fair fit in the low fluence range in most cases, the deviation was quite appreciable in the case of 1 MeV electron irradiation, and a linear change gave better fit in some cases. The large change in the carrier removal rate in electron-irradiated samples in the high fluence range was analyzed in detail in terms of the Fermi level cross-over of the defect levels. Based on the damage constants evaluated from the initial portion of data where the formula was applicable, the relative effectiveness of various radiation sources in causing the resistivity change in n-type silicon was compared. The TRIGA Mark II reactor neutrons, for example, were found to be about 40 times more effective than 1 MeV electrons. The dependence of the damage constant on the initial carrier concentration was also examined. The physical basis of the exponential law and the effect of the Fermi level cross-over of the defect levels on the resistivity change in the high fluence ranges are discussed.

• Journal of Industrial Technology
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• v.36
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• pp.83-88
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• 2016

In this study, a series of experiment was carried to improve dewaterability of the sludge produced in a treatment plant, located in Hongcheon, Gangwondo, which has been treating municipal wastewater and livestock wastewater. Optimum sludge mixing ratio and the amount of sludge conditioner were determined. As sludge conditioners, alum and ferric salt were selected and tested. For the measurement of sludge dewaterability, capillary suction time(CST) and the specific resistance were measured, The specific resistance was detemined by running a series of Buchner Funnel Test. Mixing the two sludges at a 50:50 ratio with the addition of 20 mL alum gave the best results in terms of dewaterability. The moisture content decreased by 2% at this condition.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.287-290
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• 2007

We investigated the effect of ultrasound on the dewaterability of sewage sludge. Because, dewatering and disposal of waste sludge is a major economical factor in the operation of wastewater treatment plants. Capillary Suction Time(CST) and Specific Resistance to Filtration (SRF) were used to evaluate the sludge dewatering behaviors. From the results of the experiment, it was found that ultrasonic treatment can improve the dewaterability. We discovered that CST and SRF were highly related, according to the correlation coefficient($R^{2}$).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.24 no.2
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• pp.94-100
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• 1988

Recently with the rapid development in marine and shipbuilding industries such as marine structures, ship, and chemical plants, there occurs much interest in the study of corrosion fatigue characteristics was closed up an important role in mechanical design. In this study, the 5086 Al-Alloy was tested by used of a rotary bending fatigue tester and was investigated under the environments of various specific resistance and air. The specific resistance, as a corrosion environment, was changed 15, 20, 25 and 5000$\Omega$.cm. The corrosion fatigue crack initiation sensitivity was quantitatively inspected for 5086 Al-Alloy in the various specific resistance. The experimental constants of Paris rule were examined in the various specific resistances, and the influences of load and corrosion with affect the crack growth rate were compared with. Main results obtained are as follows: (1) Number of stress cycles to corrosion fatigue crack initiation delaies and corrosion fatigue crack initiation sensitivity decreases with the increasing for the specific resistance. (2) The experimental constant m of Paris rule decreases with the decreasing for specific resistance. Hence the effect of corrosion is more susceptible than that of stress intensity factor. (3) The corrosion fatigue crack of 5086 Aluminium Alloy appears intergranular fracture. (4) Corrosion sensitivity is decreased with the increasing stress intensity factor and is nearly uniform when stress intensity factor is over 40kg.mm super(-3/2)

• Geophysics and Geophysical Exploration
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• v.16 no.2
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• pp.79-90
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• 2013

Geophysical investigation in non-destructive testing is economically less expensive than boring testing and providing geotechnical information over wide-area. But, it provides only limited geotechnical information, which is hardly used to the design. Accordingly, we performed electrical resistivity experiments on large scale of soil model to analyze the correlation between electrical resistivity response and soil water contents. The soils used in the experiments were the Jumunjin standard sand and weathered granite soil. Each soil particle size distribution and coefficient of uniformity of experimental material obtained in the experiments were maintained in a state of the homogeneous. The specifications of the model used in this study is $160{\times}100{\times}50$(cm) of acrylic, and each soil was maintained at the height 30 cm. The water content were measured using the 5TE sensors (water contents sensors) which is installed 7 ~ 8 cm apart vertically by plugging to floor. The results of the resistivity behavior pattern for Jumunjin standard sand was found to be sensitive to the water content, while the weathered granite soil was showing lower resistivity over the time, and there was no significant change in behavior pattern observed. So, it results that the Jumunjin standard sand's particle current conduction was better than the weathered granite soil's particle through contact with the distilled water. This lab test was also compared with the result of a test bed site composed of similar weathered soil. It was confirmed that these experiments were underlying research of non-destructive investigation techniques to improve the accuracy to estimate the geotechnical parameter.