• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.24 no.1
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• pp.17-21
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• 1988

To the purpose of keeping net mouth of seine with bag open in the seining operation a novel method was devised and tested with model gear that double textile strips were fixed at both side edges of bag net mouth as sheering devices. The angles of attack of inner and outer strips were the 40 in degrees by adjusting rigging. In seining operation current that flowed between the double strips and generated side force on the strips sheered and opened the net mouth automatically. This paper described dynamic characteristics of the sheering strips and its automatic opening function of net mouth.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.517-520
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• 2008

In this study, corrosion resistance of steel in cracked-reinforced concrete was performed according to experimental method. Mixed design is OPC, 30% PFA, 60% GGBS and 10% SF, respectively. Moreover, corrosion resistance test was measured using ultra testing machine for 0.3mm crack induction. The corrosion resistance of blended concrete shows the results following OPC > 10%SF > 30% PFA > 60% GGBS after 60days curing. In case of mass loss test, embedded reinforcement in OPC concrete surveyed the minimum corrosion and appeared better corrosion resistance than blended concrete. As a result, corrosion resistance of sound concrete is higher than cracked concrete. Moreover, corrosion resistance of binary concrete is lower than OPC.

• Journal of Biosystems Engineering
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• v.4 no.1
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• pp.58-66
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• 1979

동력경운기용 두류의 무경운 파종기에 부착하여 사용하는 구절기중에서 소요견인력이 작고 구절작업정도가 양호한 구절기의 개발을 위한 기초자료를 얻기 위하여 구동식 토조에 인공강토를 채우고 원판형 및 호우형 구절기의 소요견인력과 이에 영향을 미치는 인자들의 관계를 구명코자 실내모형 확험을 실시하여 다음과 같은 결과를 얻었다. 원판형 구절기에 대하여 직경별로 조립각을 $8^{\circ}$ 와 $16^{\circ}$, 경심을 3 cm 와 6cm로 변화시키면서 2.75cm/sec의 속도로 견인력을 측정한 결과 원판의 직경이 약 28cm인 경우에 견인력이 최소로 나타났고, 직경이 이보다 크거나 작은 때는 견인력이 증가하는 경향을 나타냈으며 비저항도 대체로 비슷한 경향이었으나 원판의 직경이 약 30cm 일 때 최소로 나타났다. 종자파종의 심도조절을 목적으로 작구심(3cm 및 6 cm)과 견인력과의 관계를 조사하였던바, 경심과 견인력과의 관계는 거의 직선적인 변화를 나타냈으며 견인력에 영향을 미치는 인자중에서 경심의 영향이 가장 컸음을 알 수 있었다. 일반적으로 조립각 미 주행속도에 별 영향없이 경심 3cm 및 6 cm 공히 견인력은 직경 약 28 cm에서 , 비저항은 약 30cm에서 최소의 값을 나타내었다. 파종기의 작업성능과 관계가 깊은 주행속도 및 파시의 조절을 목적으로 원판의 조립각과 주행속도가 견인력에 미치는 영향을 조사했던 바, 조립각과 주행속도가 증가함에 따라 모두 견인력이 증가하는 경향을 나타내었으나 견인력에 미치는 영향은 주행속도가 더욱 크게 나타났다. 원판형 구절기와 호우형 구절기를 비교하기 위하여 쐐기각이$16^{\circ}$ 이고 리프트 각이 $20^{\circ}$ 인 호우형 구절기와 조건이 비슷한 조립각$16^{\circ}$ 의 원판형 구절기의 견인특성을 비교한 결과 직경 30cm 인 원판형의 경우는 비저항이 0.35-0.5kg/$cm^2$인데 비해 호우형의 경우는 0.71-1.02kg/$cm^2$로 나타나 호우형의 견인저항력이 평균 2 배정도 크게 나타났고 작구상태고 원판형의 경우보다 불량하였다.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1289-1291
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• 1997

전류 센싱 MOSFET의 센싱 셀과 메인 셀의 온저항 모델을 달리 세워 원자재 산포에 따른 소자의 특성 산포 분량의 원인을 규명하였다. 에피의 농도와 두께가 증가할수록 센싱 셀의 온저항이 메인셀보다 작아지며 농도와 두께의 변화가 있을때의 온저항 변화율도 작은것으로 나타났다. 원자재 산포에 의한 SENSE FET 특성 산포를 줄이기 위해서는 정사각형 형태의 SENSE cell 배치가 효과적이며 센스 셀과 메인 셀의 간섭을 방지하기 위해서는 센싱 저항을 센스 셀의 온저항의 1/10 이하로 설계하고 간격이 최소한 에피 두께 이상이 되어야함을 밝혔다.

• Geophysics and Geophysical Exploration
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• v.10 no.2
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• pp.138-146
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• 2007

This paper describes 2.5D induced polarization (IP) modeling and inversion algorithms using complex resistivity. The complex resistivity method has merits for acquiring more valuable information about hydraulic parameters and pore fluid than the conventional IP methods. The IP modeling and inversion algorithms are developed by allowing complex arithmetic in existing DC modeling and inversion algorithms. The IP modeling and inversion algorithms use a 2.5D DC finite-element algorithm and a damped least-squares method with smoothness constraints, respectively. The accuracy of the IP modeling algorithm is verified by comparing its responses of two synthetic models with two different approaches: linear filtering for a three-layer model and an integral equation method for a 3D model. Results from these methods are well matched to each other. The inversion algorithm is validated by a synthetic example which has two anomalous bodies, one is more conductive but non-polarizable than the background, and the other is polarizable but has the same resistivity as the background. From the inverted section, we can cleary identify each anomalous body with different locations. Furthermore, in order to verify its efficiency to the real filed example, we apply the inversion algorithm to another three-layer model which includes phase anomaly in the second layer.

• Journal of the Korea Concrete Institute
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• v.19 no.1
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• pp.27-37
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• 2007

The purpose of this study is to propose a method to predict the minimum curing time of early age concrete required to prevent frost damage. Tests were performed to examine major factors, which affect the compressive strength of concrete frozen at early ages and investigate the source of frost damage at early age concrete. The results from the tests showed that the loss rate of compressive strength decreases as the beginning time of frost damage was delayed and water-cement ratio was lower. In addition, the test results also showed that concrete made with type III cement was less susceptible to frost damage than concrete made with ordinary Portland cement and frost damage occurred through the formation of ice lenses. When early age concrete is being damaged by frozen, a phase transition into ice of free water presented at the capillary pores of the concrete gives a reason for the decrease of compressive strength. Accordingly, the frost resistance of fresh concrete can be determined based on the saturation degree of the capillary pores. The method to predict the minimum curing time was suggested using the concept of critical saturation degree of the capillary pores.

• Journal of the Society of Disaster Information
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• v.14 no.2
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• pp.122-129
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• 2018

Purpose : This study aims to seek out the risk of low-temperature burns and fire. Method : Hot vests are connected by higher voltage than walking voltage. Results : Accordingly, the possibility of low-temperature burns and fire was proved high. It was also shown that hot vests with relatively lower resistance on heat rays reached a higher temperature as the same voltage was applied. Conclusion : There are some problems with hot vests because they do not have any safety devices like a thermostat or a timer to prevent temperature increasing rapidly. For the purpose of reducing the risk of low-temperature burns and fire, setting the standard of the minimum resistance temperature and regulating the use of heat rays with lower resistance are necessary.

• Korean Journal of Materials Research
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• v.10 no.1
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• pp.90-96
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• 2000

The effects of the type and thickness of underlayers on the crystallographic texture and the sheet resistance of aluminum thin films were studied. Sputtered Ti and Ti/TiN were examined as the underlayer of the aluminum films. The texture and the sheet resistance of the metal thin film stacks were investigated at various thicknesses of Ti or TiN, and the sheet resistance was measured after annealing at $400^{\circ}C$ in an nitrogen ambient. For the Ti underlayer, the minimum thickness to obtain excellent texture of aluminum <111> was 10nm, and the sheet resistance of the metal stack was greatly increased after annealing due to the interdiffusion and reaction of Al and Ti. TiN between Ti and Al could suppress the Al-Ti reaction, while it deteriorated the texture of the aluminum film. For the Ti/TiN underlayer, the minimum Ti thickness to obtain excellent texture of aluminum <111> was 20nm, and the minimum thickness of TiN to function as a diffusion barrier between Ti and Al was 20nm.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.11
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• pp.1282-1285
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• 1988

A novel temperature difference-to-frequency converter using two resistance temperature detectors (RTD) has been developed. The resistance difference of two RTD is converted into its equivalent inductance to form the resonant circuit of the Colpitts oscillator. The conversion sensitivity of 16 Hz/$^{\circ}C$ and the residual nonlinearity less than 2.15% over the temperature difference range from 35$^{\circ}C$ to 155$^{\circ}C$ are obtained by the prototype converter. The frequency drift of oscillator itself is $\pm$ 0.5Hz. Thus, the minimum detectable temperature difference is estimated to be $\pm$ 0.013$^{\circ}C$. The proposed coverter, except for two RTD, can be fabricated in monolithic IC form.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.169-169
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• 2010

박막형 CIGS 태양전지의 배면전극으로 사용되는 Mo 박막은 낮은 저항으로 인한 전기전도성과 열적 안전성이 아주 우수하다. 연구에서는 연성 CIGS 태양전지의 제조를 위한 Mo 배면전극의 대면적 증착기술에 관한 것으로 DC Magnetron Sputtering 공정을 이용하여 전주기술을 통한 Ni-Fe계 연성기판재 위에 졸걸법으로 합성된 $SiO_2$ 절연박막에 Mo 박막을 증착하는 것을 목적으로 하고 있다. 실험에서는 연성기판재 대신 시편을 Sodalime glass, Si wafer, SUS계 소재를 사용하여 스퍼터링 공정에 의한 Mo 박막을 증착하였다. 실험에서 타겟에 인가되는 전력과 공정압력을 변수로 하여 Mo 박막의 증착율, 전기저항성을 측정하였다. 타겟의 크기는 $80mm{\times}350mm$, 타겟과 기판간 거리 20cm 이었으며, 공정 압력은 2~50 mtorr 영역에서 인가전력을 0.5-1.5kW로 하였다. Mo 박막의 증착율과 전기적 특성을 측정하기 위하여 $\alpha$-step과 4-point probe(CMT-SR 1000N)를 이용하였다. 그리고 Mo 박막의 잔류응력을 측정하기 위하여 잔류응력측정기를 이용하였다. Mo 박막의 미세구조분석을 위하여 SEM 및 XRD를 분석을 실시하였다. 배면전극으로서 전기저항성은 공정압력에 따라 좌우 되었으며, 2 mTorr 공정압력과 1.5kW의 전력에서 최소값인 $8.2\;{\mu}{\Omega}-cm$의 저항값과 증착율 약 $6\;{\mu}/h$를 보였다. 기판재와의 밀착성과 관련한 잔류응력 측정과 XRD분석을 통한 결정립 크기를 분석하여 공정압력에 따른 Mo 박막의 잔류응력과 전기 저항 및 결정립 크기의 상관관계를 조사하였다. 그리고 대면적 CIGS 증착공정을 위해 직각형 타겟을 통해 증착된 Mo 박막의 증착분포를 20cm 이내 조사하였다.