• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.141-141
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• 2004

다이아몬드상 탄소(diamond-like carbon, DLC) 박막은 명칭에 함축된 의미로 알 수 있듯이 다이아몬드와 유사한 특징을 지니고 있다. DLC 박막은 비정질(amorphous) 고상 탄소 박막으로 구조적으로 Sp$^1$, Sp$^2$, Sp$^3$의 결합들로 구성되어 있다. DLC 박막의 물성으로는 우수한 경도, 내마모성, 낮은 마찰계수, 화학적 안정성 그리고 적외선(IR) 영역에서의 높은 투과율 등이 있다. 현재 DLC 박막은 앞서 열거된 물성들의 장점을 활용하여 다양한 산업분야에서 활발히 응용되고 있다.(중략)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.641-646
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• 2003

The dielectric carbon nitride thin films were deposited onto Si(100) substrate using a pulsed laser ablation of pure graphite target combined with a high voltage discharge plasma in the presence of a N$_2$ reactive gas. We calculated dielectric constant, $\varepsilon$$\_$s/, with a capacitance Schering bridge method. We investigated the influence of the laser ablation of graphite target and DC high voltage source for the plasma. The properties of the deposited carbon nitride thin films were influenced by the high voltage source during the film growth. Deposition rate of carbon nitride films were increased drastically with the increase of high voltage source. Infrared absorption clearly shows the existence of C=N bonds and C=N bonds. The carbon nitride thin films were observed crystalline phase confirmed by x-ray diffraction data.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.4
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• pp.49-54
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• 2005

In this paper, micro structuring technique using localized electrochemical deposition (LECD) with ultra short pulses was investigated. Electric field in electrochemical cell was localized near the tool tip end region by applying pulses of a few hundreds of nano second duration, Pt-Ir tip was used as a counter electrode and copper was deposited on the copper substrate in mixed electrolyte of 0.5 M $CuSO_4$ and 0.5 M $H_2SO_4$, The effectiveness of this technique was verified by comparison with ECD using DC voltage. The deposition characteristics such as size, shape, surface, and structural density according to applied voltage and pulse duration were investigated. The proper condition was selected based on the results of the various experiments. Micro columns less than $10{\mu}m$ in diameter were fabricated using this technique. The real 3D micro structures such as micro spring and micro pattern were made by the presented method.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.281-286
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• 2022

In this study, design of an intuitive internal resistance diagnostic device is to diagnose the residual capacity and aging of the battery regardless of the model and the internal protocol of the waste battery through the method of measuring the internal resistance of a waste battery. In this paper, charging and discharging were continuously performed with 2A charging and 5A discharging in order to secure data on impedance changes that may occur in the charging and discharging process of various methods. As a result of the final experiment, it was confirmed that the impedance change occurred during charging and discharging, and the amount of change increased as the charging/discharging C-rate increased. In addition, it was confirmed that the waste battery aged or abnormal cell had a large change in the impedance value.

• Analytical Science and Technology
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• v.10 no.4
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• pp.264-273
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• 1997

Anodic oxidation reaction was applied to remove trihalomethanes in an aqueous solution. Each component was determined by using solid phase microextraction(SPME) fiber and GC-ECD. Anodic and cathodic compartments were separated in order to protect contaminants and connected by $KNO_3$-agar bridge. The calibration graphs of the 6 THM components were shown good linearlity from a few ppb up to a few hundreds ppb concentration level. Anodes such as platinum(Pt), titanium(Ti). zircornium(Zr), titanium metal coated with iridium(Ti-Ir), and glassy carbon coated with mixed valence ruthenium(mv Ru) were tried to remove the THMs at different potentials. The best result was obtained on the Ti-Ir anode applied 9 volts DC. The electrode could effectively remove almost all the THM components from the stirring solution within about 1.5 hours. The glassy carbon electrode coated with mixed valence ruthenium showed excellent removing effect at the begining, but the maximum removing level was remained at 60% probably due to the destruction of the electrode surface. The concentration of chloroform, however, tends to be increased due to the electrode reaction producing the component at the condition.

• Journal of the Korean Magnetics Society
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• v.24 no.4
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• pp.101-106
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• 2014

The glass/Ta(5.8 nm)/NiFe(5 nm)/Cu(2.3 nm)/NiFe(3 nm)/IrMn(12 nm)/Ta(5.8 nm) GMR-SV (giantmagneto-resistance-spin valve) multilayer structure films with a magnetoresistance ratio (MR) of 5.0 % and a magnetic sensitivity (MS) of 1.5%/Oe was deposited by dc magnetron sputtering method. Also, GMR-SV device having a width of $7{\mu}m{\sim}8{\mu}m$ similar to the diameter of RBC (red blood cell) was fabricated by the light lithography process. When RBCs coupled with several magnetic beads with a diameter of $1{\mu}m$ dropped upon the GMR-SV device having MR = 1.06% and MS = 0.3 %/Oe, there is observed the variation of about included of a resistance value of ${\Delta}R=0.4{\Omega}$ and ${\Delta}MR=0.15%$ around a external magnetic field of -0.6 Oe. From these results, the GMR-SV device having the width magnitude of a few micron size can be applied as the biosensor for the analysis of a new magnetic property of hemoglobin inside of RBC combined to magnetic beads.

• Journal of the Korean Chemical Society
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• v.58 no.5
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• pp.456-462
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• 2014

Binary-doped conducting chiral polyaniline (PAni) was synthesized by electrochemical polymerization of aniline at low-temperature ($0^{\circ}C$) and room-temperature (RT) conditions. (+)-Camphorsulfonic acid (CSA) and hydrochloric acid (HCl) were used as a binary dopant. Formation of the binary-doped PAni rather than a mixture of the corresponding single-doped PAni was confirmed by cyclic voltammogram, FT-IR and circular dichroism spectra. The temperature influenced the electrochemical behavior and doping level, thus determining the crystallinity and morphology of the PAni. However, among other results, morphology of the PAni is found to be most strongly depends on the polymerization temperature. With increased temperature from the initial state to RT, morphology of the PAni changed from fibrous to short-fibrous structure. The sheet resistance of the PAni films on an ITO was measured by using four-point probe dc method.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.955-960
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• 2004

The treated ballast water from previous treatment contains microorganisms and pathogenic organisms in an electrolytic treatment system. The experimental methods included using a peristaltic flow pump placed upward on an electrode pole. Due to the reaction time, the hydraulic retention time indicated unlike microorganisms on the flow rate. In electrolysis, dioxide iridium-coated titanium (Ti/Ir02) and stainless steel plates were used for the anode and cathode, respectively. Current density controls make use of a DC power supply on 250V, 100Amper. Experimental use of a current density between 0.1 and 1.0A/dm2 was able to disinfect the microorganism (E. coli, Bacteria, Bacillus sp.) in seawater for 5 seconds of reaction time. The removal rate was approximately $90\%,$ while the current density was 2.0A/dm2 and the electrode distance was 75mm. This study shows that the electrolytic treatment system has a potential for the sterilization of ballast water.

• Journal of IKEEE
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• v.17 no.3
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• pp.275-283
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• 2013

In this paper, a 8bit 10Ms/s CMOS Folding and Interpolation analog-to-digital convertor is proposed. The architecture of the proposed ADC is based on a Folding & Interpolation using FR(Folding Rate)=8, NFB(Number of Folding Block)=4, IR(Interpolation Rate)=8. The proposed ADC adopts a preamplifier sharing method to decrease the number of preamplifier by half comparing to the conventional ones. This chip has been fabricated with a 0.35[um] CMOS technology. The effective chip area is $1.8[mm]{\times}2.11[mm]$ and it consumes 20[mA] at 3.3 power supply with 10[MHz] clock. The INL is -0.57, +0.61 [LSB] and DNL is -0.4, +0.51 [LSB]. The SFDR is 48.9[dB] and SNDR is 47.9[dB](ENOB 7.6b) when the input frequency is 100[kHz] at 10[MHz] conversion rate.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.182.2-182.2
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• 2015

최근 학계나 산업계에서 투명 전자 소자에 대하여 활발한 연구가 진행되면서, 투명 전 도성 산화물(TCO: transparent conductive oxide)에 대한 관심이 높아지고 있다. 대표적인 TCO 물질인 Indium Tin Oxide (ITO)는 가시 광 영역에서의 높은 투과 및 높은 도전성을 가져 전압을 인가하면 발열이 가능하므로 이를 투명 면상 발열체에 적용시키는 연구가 활발히 진행되고 있다. 하지만, ITO는 발열 테스트 결과 온도가 상승함에 따라 발열이 일부분에 집중되는 현상이 있으며, 전도성을 높이기 위하여 추가공정이 필요하다. 또한, 글라스의 곡면 부분에서 ITO를 사용하면 유연성이 부족하므로 크랙이 발생한다는 단점이 있다. 따라서, 최근 Silver nanowire (AgNW), Single-walled Carbon nanotube (SWCNT), ITO를 기반으로 한 AgNW에 ITO를 증착 하거나 SWCNT를 코팅하여 우수한 전기적, 광학적 특성을 지닌 하이브리드 전극이 투명 면상 발열체 재료로서 사용되고 있다. 하지만 대체된 재료들도 다양한 문제점을 가지고 있다. 예를 들어 고온에서 발열을 유지하지 못하고 끊어지거나 가시광영역의 투과율이 낮은 점 등이 있다. 이런 다양한 문제점들을 보완 할 수 있는 새로운 투명 면상 발열체에 적용한 연구가 요구되고 있다. 본 연구에서는 GZO/Ag/GZO 하이브리드 구조의 투명 면상 발열체를 제작하여 전기적, 광학적 특성을 비교하고 발열량, 온도 균일 성, 발열 유지 안정도를 확인하였다. 본 연구에서는 $50{\times}50mm$ 크기의 Non-alkali glass (삼성코닝 E2000) 기판 상에 DC마그네트론 스퍼터링 공정을 이용하여 상온에서 GZO, Ag, GZO 박막을 연속적으로 증착 하여 다층구조의 하이브리드형 투명 면상 발열체를 제조하였다. 박막 증착 파워는 DC (Ag) power 50 W, RF (GZO) power 200 W로 하였으며 GZO박막두께는 45 nm로 고정 시키고 Ag박막 두께는 5~20 nm로 변화를 주었다. 증착원은 3인치 GZO 세라믹 타깃 (2.27 wt. % Ga2O3) 과 Ag 금속 타깃 (순도 99.99%)을 사용하였으며, Ar을 40 sccm 주입 후 Working pressure는 고 순도 Ar을 사용하여 1.0 Pa로 고정하며 10분간 Pre-sputtering을하고 증착을 진행하였다. 앞선 실험을 통해 증착한 박막의 전기적, 광학적 특성은 각각 Hall-effect measurements system (ECOPIA, HMS3000), UV-Vis spectrophotometer (UV-1800, Shimadzu)를 사용해 측정 되었으며, 하이브리드 표면의 구조 및 형상은 FESEM으로 관찰하였다. 또한 표면온도 측정기infrared camera (IR camera)를 이용하여 4~12 V/cm의 전압을 인가 시 시간에 따른 투명 면상 발열체의 표면 온도변화를 관찰하였다.