• 한국안전학회지
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• 제16권4호
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• pp.22-28
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• 2001

Heat transfer and pressure distribution for heat exchanger type of domestic gas boiler are different from shape, pitch, thickness of fin and array of pipe respectively. In order to measure the pressure distribution across the heat exchanger, a suction type wind tunnel was constructed and velocity distribution was measured for pilot tube(4 point) of rack type. The experiments were performed for 5 different air flow mass, rpm=3,6,9,12,15 and transverse axis of heat exchanger(x-length) is 5cm respectively. Results showed that above 9.5m/s, pressure distribution dispersion for wet type of heat exchanger is on the increase and above 5.5m/s, pressure distribution dispersion for dry type of heat exchanger is on the increase. Also, pressure distribution dispersion by comparing two different types heat exchanger, dry type of heat exchanger showed a higher augmentation than wet type of heat exchanger.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.317-320
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• 1999

In this study, the piezoelectric ceramics PZT powder was synthesized by Wet-Dry combination method. And the flexible 1-3-0 type composites were fabricated with piezoceramic PZT and Eccogel polymer matrix embedded 3rd phase. Dielectric constant of 1-3-0 type composites was lower than that of single phase PZT ceramics. Thickness mode coupling factor k/sub t/ which was comparable with single phase PZT ceramics and mechanical quality factor Qm were about 0.65 and 6, respectively. These composites are considered as a good candidates for broad-band type transducer applications. The acoustic impedance of 1-3-0 type composites was lower than that of single phase PZT ceramics. Therefore, these composites would be better used for hydrophone applications.

• Computers and Concrete
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• 제3권2_3호
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• pp.145-161
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• 2006

This article involves architecting prototype-fuzzy expert system for designing the nominal cover thickness by means of fuzzy inference for quantitatively representing the environment affecting factor to reinforced concrete in chloride-induced corrosion environment. In this work, nominal cover thickness to reinforcement in concrete was determined by the sum of minimum cover thickness and tolerance to that defined from skill level, constructability and the significance of member. Several variables defining the quality of concrete and environment affecting factor (EAF) including relative humidity, temperature, cyclic wet and dry, and the distance from coast were treated as fuzzy variables. To qualify EAF the environment conditions of cycle degree of wet-dry, relative humidity, distance from coast and temperature were used as input variables. To determine the nominal cover thickness a qualified EAF, concrete grade, and watercement ratio were used. The membership functions of each fuzzy variable were generated from the engineering knowledge and intuition based on some references as well as some international codes of practice.

• Corrosion Science and Technology
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• 제9권1호
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• pp.34-38
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• 2010

Electrochemical study on cut edge corrosion of prepainted Zn coated (GI) and 55%Al-Zn coated (GL) steels has been performed in wet-dry cyclic conditions. Maximum width of delaminated polymer coating from the cut edge for GI and GL specimens was evaluated under wet-dry cyclic conditions. The cyclic tests were carried out for 1000 h by changing of relative humidity, where the salt of NaCl was deposited on the specimen every 48 h. The cut edge corrosion test under NaCl deposit indicated that the delamination of the GL specimen progresses at a higher rate than the GI. The electrochemical corrosion monitoring was also performed under condition of alternate exposure to immersion in NaCl solution and drying at 60%RH and $25^{\circ}C$. On the basis of the results of the delamination tests and electrochemical measurements, the mechanism of cut edge corrosion for GI and GL were discussed.

• Macromolecular Research
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• 제8권4호
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• pp.153-164
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• 2000

By electrodeposition (ED) using a monomeric- and two polymeric coupling agents, the interfacial shear strength (IFSS) of carbon fiber/epoxy composites was investigated by fragmentation test. ED results were compared with the dipping and the untreated cases under dry and wet conditions. Multi-fiber composites (MFC) were used for the direct comparison for the untreated and the treated cases. Various treating conditions including time, concentration and temperature were evaluated, respectively. Under dry and wet conditions ED treatment exhibited much higher IFSS improvement compared to the dipping and the untreated cases. Monomeric- and polymeric coupling agents exhibited the comparative IFSS improvement. Adsorption mechanism between coupling agents and carbon fiber was analyzed in terms of the electrolyte molecular interactions during ED process based on to the chain mobility. The microfailure modes occurring from the fiber break, matrix and interlayer cracks were correlated to IFSS.

• 한국재료학회지
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• 제12권5호
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• pp.327-333
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• 2002

In order to obtain the oxidation layer for SiC MOS, the oxide layers by thermal oxidation process with dry and wet method were deposited and characterized. Deposition temperature for oxidation layer was $1100^{\circ}C$~130$0^{\circ}C$ by $O_2$ and Ar atmosphere. The oxide thickness, surface morphology, and interface characteristic of deposited oxide layers were measurement by ellipsometer, SEM, TEM, AFM, and SIMS. Thickness of oxidation layer was confirmed 50nm and 90nm to with deposition temperature at $1150^{\circ}C$ and $1200{\circ}C$ for dry 4 hours and wet 1 hour, respectively. For the high purity oxidation layer, the necessity of sacrificial oxidation which is etched for the removal of the defeats on the wafer after quickly thermal oxidation was confirmed.

• 한국환경과학회지
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• 제17권12호
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• pp.1325-1330
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• 2008

This study was carried out with the detection for multiresidue of the carbamate pesticide such as carbaryl and cabofuran by enzyme-inhibition method. The check time for determination of acetylcholinesterase(AChE) activity was selected at 60 sec. The AChE activity in chicken brain determined by the Ellman's method was $162{\mu}$mol/min/g protein. $I_{50}$ for AChE by carbamate pesticide with wet kit was 0.169mg/L of carbaryl and 0.089mg/L of cabofuran, respectively. The incubation time for enzyme kit with substrate kit was 30min for determination of AChE activity. Enzyme kit with substrate kit was stable at $4^{\circ}C\;and\;25^{\circ}C$ for 5 days. Limit detection concentration of carbaryl with dry kit for AChE was 0.05mg/L. The dry kit such as wet kit applied Enzyme-Inhibition(EI) method with AChE was confirmed the multi residue method to detect the carbamate pesticides.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.57-65
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• 2016

By high speed Liquid Droplet Impingement (LDI) on material, fluid systems are seriously damaged, therefore, it is important for the solution of the erosion problem of fluid systems to consider the effect of material in LDI. In this study, by using an in-house fluid/material two-way coupled method which considers reflection and transmission of pressure, stress and velocity on the fluid/material interface, high-speed LDI on wet/dry material surface is simulated. As a result, in the case of LDI on wet surface, maximum equivalent stress are less than those of dry surface due to damping effect of liquid film. Empirical formula of the damping effect function is formulated with the fluid factors of LDI, which are impingement velocity, droplet diameter and thickness of liquid film on material surface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.303-306
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• 1999

In this study, the piezoelectric ceramics PZT powder was synthesized by Wet-Dry combination method. The flexible 1-3-0 type composites were fabricated with piezoceramic PZT and Eccogel polymer matrix embedded 3rd phase. This paper represents the acoustic properties with various 3rd phase wt.%. The acoustic impedance of 1-3-0 type composites was lower than that of single phase PZT ceramics. The pulse-echo response of transducer fabricated with 1-3-0 type composites was better than solid PZT transducer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1933-1935
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• 2005

In this investigation, the electrochemical behaviour of magnesium alloy anode was studied by using electrochemical methods and the performance of magnesium alloy anode was observed with dry and wet backfill under accelerated cathodic protection. This paper reports the data collected at the laboratory and field sites over one year exposure of magnesium anode under cathodic protection donditions.