• 한국표면공학회지
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• 제53권4호
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• pp.190-199
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• 2020

Copper pyrophosphate baths were employed in order to study the dependencies of current efficiency, residual stress, surface morphology and microstructure of electrodeposited Cu thin layers on applied current density. The current efficiency was obtained to be more than about 90 %, independent of the applied current density. Residual stress of Cu electrodeposits was measured to be in the range of -30 MPa and 25 MPa with the increase of applied current density from 0.5 to 15 mA/㎠. Relatively smooth surface morphologies of the electodeposited Cu layers were obtained at an intermediate current range between 3 and 4 mA/㎠. The Cu electrodeposits showed FCC(111), FCC(200), and FCC(220) peaks and any preferred orientation was not observed in this study. The average crystalline size of Cu thin layers was measured to be in the range of 44~69 nm.

• 한국산학기술학회논문지
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• 제6권2호
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• pp.110-115
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• 2005

표면 경화가 요구되는 소재에 코발트계 합금 분말을 용사 소모재로 하고 플라즈마 트랜스퍼드 아크(PTA) 용사 공정을 이용하여 표면 개질부를 제조하였다. 표면 개질부는 다른 용사 변수는 일정하게 유지한 상태에서 용사 전류만을 변화하여 제조하였다. 용사 전류를 80에서 140 amp까지 20 amp씩 증가하면서 개질층을 제조하였다. 두께가 일정한 모재에 전류를 변화하여 표면 개질층을 제조하는 경우 용사후 모재에서 발생하는 냉각 효과가 다르게 되고 이는 개질층의 폭과 두께 등의 기하학적 형상과 미세 조직, 그리고 미세경도 등의 특성에 영향을 미치는 것으로 나타났다. 용사 전류를 120amp로 사용한 경우 미세조직이 조밀하고 미세경도 값이 가장 높은 값을 나타내는 개질층을 얻을 수 있었다. 전류를 증가함에 따라 개질층의 폭은 증가하지만 높이는 큰 변화가 없는 것으로 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.47-50
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• 2002

The displacemant current measuring system used for detecting the dynamic behavior of monolayers at the air-water interface is described. It basically consists of a film balance, a pair of electrodes connected to each other through a sensitive ammeter. Here, one electrode is suspended in air and the other electrode is placed in the water. With Maxwell-displacement-current-measuring method, the phase transitons of $Poly-{\gamma}-benzyl_{L}$ -glutamate (PBLG) and $Poly-{\gamma}-benzyl_{D}$-glutamate(PBDG) on a water surface were detected. Measured surface pressure, displacement current and dipole moment of monolayers of PBLG and PBDG on the water surface. Also, we measured that compression velocity (30, 40, 50[mm/min]) when the sample spread volume was about 370[ul]-400[ul] and displacement current that occur when differed temperature. From the result, it is known that current is generated in the range of high surface pressures as compression velocity become faster and increase of temperature.

• 한국표면공학회지
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• 제51권6호
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• pp.400-404
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• 2018

A metal 3D printer has been developed on its own to electrodeposit the localized area. Nozzles were used to selectively laminate the electrolytic plating method. To analyze the factors affecting the deposition, the stack height, thickness and surface roughness were experimentally analyzed according to the current density and the temperature of the electrolyte. Electrolytic temperature and current are electrodeposited when the deposition conditions are dominant over the etching conditions, but the thickness is kept constant. On the contrary, when the etching conditions are dominant, the electrodeposited shape is rather the etched. As a result, the uniformity of surface quality and electrodeposition rate could be improved by conducting experiments under constant conditions of electrolyte temperature and current density.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2022년도 추계학술대회
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• pp.323-324
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• 2022

본 눈문은 X-밴드 레이더 이미지를 이용한 표층해류 계측 비교 결과를 분석한다. 속초해수욕장에 설치된 선박용 X-밴드 레이더를 이용해 2022년 2월 기간 동안 표층해류 계측을 진행하였다. 국립해양조사원 해양 관측 부이의 자료를 기준으로 하여 계측 데이터 비교 및 분석을 통해 표층해류(유속) 계측 정확도를 입증했다.

• 한국표면공학회지
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• 제50권1호
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• pp.17-23
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• 2017

This work demonstrates arc generation and anodic film formation behaviors on Al1050 alloy during PEO (plasma electrolytic oxidation) treatment under a constant direct current in an alkaline electrolyte containing silicate, carbonate and borate ions. Only one big arc more than 2 mm diameter was generated first at the edges and it was moving on the fresh surface or staying occasionally at the edges, resulting in the local burning due to generation of an extremely big orange colored arc at the edges. Central region of the flat surface was not fully covered with PEO films even after sufficiently long treatment time because of the local burning problem. The anodic oxides formed on the flat surface by arcing once were found to consist of a number of small oxide nodules with spherical shape of $3{\sim}6{\mu}m$ size and irregular shapes of about $5{\sim}10{\mu}m$ width and $10{\sim}20{\mu}m$ length. The anodic oxide nodules showed uniform thickness of about $3{\mu}m$ and rounded edges. These experimental results suggest that one big arc observed on the specimen surface under the application of a constant direct current is composed of a number of small micro-arcs less than $20{\mu}m$ size.

• 한국표면공학회지
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• 제50권2호
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• pp.72-84
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• 2017

In this work, electrophoretic paint (E-paint) was deposited on AZ31 Mg alloy after four different surface pretreatments: knife abrading, SiC paper abrading, deionized (DI) water immersion and NaOH immersion. The deposition process of E-paint was studied by analyses of voltage-time and current-time curves, amount of deposited paint, current efficiency and surface oxide film resistance and the adhesion of E-paint was examined by tape test before and after immersion in DI water for 500 h at $40$^{\circ}C$. It was found that the induction time for the deposition, the amount of deposited paint and the current efficiency are inversely proportional to the resistances of surface films prepared by different surface pretreatment methods. The electrophoretic painting showed longer inductance time, larger amount of deposited paint and higher current efficiency on the highly conducting surfaces, such as knife-abraded and SiC-abraded surfaces than on the less conducting surfaces, such as DI water-immersed and NaOH-immersed samples. Excellent adhesion was observed on the E-paintings deposited onto knife-abraded and SiC-abraded AZ31 Mg alloy samplesSiC-abraded AZ31 Mg alloy samples.

• 통합자연과학논문집
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• 제3권3호
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• pp.148-152
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• 2010

Photoluminescence properties and surface morphologies of porous silicon etched with various applied current densities at fixed etching times. FE-SEM image of porous silicon surface indicated that the porous silicon prepared at currents below 200 mA exhibited very bright red photoluminescence properties. As the applied current densities increased, the photoluminescence efficiencies of porous silicon prepared at applied current densities above 300 mA decreased, and displayed the cracked surface on porous silicon. This cracked surface start to collapsed to give cracked domains.

• Journal of the korean society of oceanography
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• 제37권3호
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• pp.187-195
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• 2002

The characteristics of surface circulation in the Yellow Sea and the East China Sea are discussed by analyzing a great deal of current data observed by 142 sets of mooring buoy and 58 sets of drifters trajectories collected in the Yellow Sea and the East China Sea through domestic and abroad measurements. Some major features are demonstrated as bellow: 1) Tsushima Warm Current flows away from the Kuroshio and has multiple sources in warm half year and comes only from Kuroshio surface water in cold half year. 2) Taiwan Warm Current comes mainly from the Taiwan Strait Water in warm half year and comes from the intruded Kuroshio surface water and branches near 27N in cold half year. 3) The Changjiang Diluted Water turns towards Cheju Island in summer and flows southward along the coastal line in winter. 4) The study sea area is an eddy developing area, especially in the southern area of Cheju Island and northern area of Taiwan.

• 전자공학회논문지D
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• 제35D권3호
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• pp.11-17
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• 1998

Although GaAs HBTs are very attractive for high power amplifier because of their power handling capablity, they can't be actively commercialized due to the degradation of current gain occured in hihg current operation. In this paper we analyzed the type of current gain degradation of GaAs HBTs under high constant current stress, and identified the mechanism by using two dimensional numerical simulation. The cause of degradation was found out to be the variation of surface recombination states at the interface between GaAs extrinstic base and the nitride passivating the surface of base. The energy radiated from recombination of carriers in bulk as well as near the surface is estimated to activate the change of the surface states.