• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.1073-1081
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• 2005

This paper describes a 3.3 V 10 bit CMOS digital-to-analog converter with a divided architecture of a 7 MSB and a 3 LSB, which uses an optimal Thermal-to-Binary Decoding method. Most of Dfh converters with hiか speed current drive are an architecture choosing current switch cell, column, row decoding method but this decoding circuit is complicated, occupies a large chip area. For these problems, this paper describes a D/A converter using an optimal Thermal-to-Binary Decoding method. The designed D/A converter with an active chip area of $0.953\;mm^2$ is fabricated by using a 0.35um process. The simulation data shows that the rise/fall time, settling time, and INL/DNL are 1.92/2.1 ns, 12.71 ns, and a less than ${\pm}2.3/{\pm}58$ LSB, respectively. The power dissipation of the D/A converter with a single power supply of 3.3 V is about 224 mW.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.549-557
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• 2012

In this paper an on-chip photo energy harvesting system with MPPT(Maximum Power Point Tracking) control is proposed. The ISC(Integrated Solar Cell) is implemented using p-diff/n-well diodes available in CMOS processes. MPPT control is implemented using the linear relationship between the open-circuit voltage of a PV(Photovoltaic) cell and its MPP(Maximum Power Point) voltage such that a small pilot PV cell can track the MPP of a main PV cell in real time. Simulation results show that the designed circuit with the MPPT control delivers the MPP voltage to load even though the load is heavy such that the load circuit can operate properly. The proposed circuit is designed in 0.18um CMOS process. The designed main PV cell and pilot PV cell occupy $8mm^2$ and $0.4mm^2$ respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.267-271
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• 2012

In this paper a power management unit for solar energy harvesting is proposed. If solar energy is sufficient, Power Management Unit(PMU) directly supplies load with solar energy. By contrast, if solar energy is insufficient to operate sensor nodes, voltage booster(VB) boosts the solar cell's output voltage, and then PMU supplies load with the harvested energy. The designed circuit had been fabricated using a 018um CMOS process. In the first case, the PMU supplies load with more energy than in the second case. In the second case where a VB is used, the PMU operates to supply load with solar energy even when illumination is low and minimum solar cells with very low output voltage are used.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.152-152
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• 2011

Silicon 기반의 환경에서 연구 및 제조되는 전자소자는 반도체의 기술이 발전함에 따라 chip 선폭의 크기가 30 nm에서 20 nm, 그리고 그 이하의 크기로 점점 더 작아지는 요구에 직면하고 있다. 탄소나노 구조와 나노와이어 기술이 Silicon을 대신할 다음세대 기술로 주목받고 있다. 많은 연구결과들 중에서 III-V CMOS가 가장 빠른 접근 방법이라 예상한다. III-V족 물질을 이용하면 electron 보다 수십 배 이상의 이동도를 얻을 수 있으나 p-type의 구조를 구현하는 것이 해결해야 할 문제이다. p-type 3-5 족 화합물을 이용하여 에너지 밴드 갭의 변화를 가능하게 한다면 hole의 이동도를 크게 향상시킬 수 있어 silicon 기반의 p-type 소자보다 2~3배 더 빠른 소자의 구현이 가능하다. 3-5족 화합물 반도체의 성장 기술이 많이 진보되어 이를 이용하여 고속 소자를 구현한다면 시기적으로 더욱 빨리 다가올 것이라 예측한다. 에너지 밴드갭의 변화와 격자 부정합을 고려하여 SI InP 기판에 GaSb 물질을 채널로 사용한 p-type 2-dimensional hole gas (2DHG) 소자를 구현하였다. 관찰된 소자 구조의 박막 상태의 특징을 보이며 10 um ${\times}$ 10 um AFM 측정결과 1 nm 이하의 표면 거칠기를 가지며 상온에서의 hole 이동도는 약 650 cm2/Vs이고 sheet carrier density는 $5{\times}1012$ /cm2의 결과를 확인하였다. 실험결과 InP 기판위에 채널로 사용된 GaSb 박막을 올리는데 있어 가장 중요한 것은 Phosphorus, Arsenic, 그리고 Antimony 물질의 양과 이들의 변화시간의 조절이다. 본 발표에서 Semi-insulating InP 기판위에 electron이 아닌 hole을 반송자로 이용한 차세대 고속 전자소자를 구현하고자 하여 MBE (Molecular Beam Epitaxy)로 p-type 소자를 구현하여 실험하였다. 아울러 더욱 빠른 소자의 구현을 위하여 세계의 유수 그룹들의 연구 결과들과 앞으로 예상되는 고속 소자에 대해서 비교와 함께 많은 기술에 대해 논의하고자 한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.249-249
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• 2015

Silver films have been of considerable interest for years due to their better performance relative to other metal films for engineering applications. A series of multi-layer silver coatings with different thickness (i.e. 0.3 um to 1.5 um) were prepared on Aluminium substrate containing copper undercoat by direct current (DC) magnetron sputtering method. For the comparative purpose, similar thickness silver coatings were prepared by electrolytic deposition method. Microstructural, morphological, and mechanical characteristics of the silver coatings were evaluated by means of scanning electron microscope (SEM), X-ray diffraction (XRD), Surface roughness test, microhardness test and nano-scratch test. From the results, it has been elucidated that the silver films prepared by DC magnetron sputtering method has superior properties in comparison to the wet coating method. On the other hand, DC magnetron sputtering method is relatively easier, faster, eco-friendly and more productive than the electrolytic deposition method that uses several kinds of hazardous chemicals for bath formulation. Therefore, a New Work Item Proposal (NWIP) for the test methods standardization of DC magnetron sputtered silver coatings has recently been proposed via KATS, Korea and a NP ballot is being progressed within a technical committee "ISO/TC107-metallic and other inorganic coating".

• Journal of Acupuncture Research
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• v.17 no.3
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• pp.10-24
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• 2000

1. Objectives : Millions of people throuout the world are affected by some form of dry eye disorder. I made researches for more effective treatments for dry eye. 2. Methodes : I refered to occidental and oriental medical records. 3. The results were as follows : Common symptoms of dry eye are dryness, burning, irritation, grittiness, itching, fatigue of eye, photophobia, congestion, mattering and tear. Treatments of dry eye are to clear away heat and fire, remove dampness, replenish Um and promote production of body fluid, tonify the blood and replenish Ki. Acupunctre and moxibustion therapy of dry eye are as follows: Very busy points of traditional regular acupuncture are Sangsong, Chanjuk, Sajukkong, Chongmyong, Sabaek, Tongjaryo, Taeyang, Pungji, Tuimup, Paekoe, Un-gyo, Chonjong, Hapkok, Yangbaek, Kansu, Yanggye, Imup, Chok-samni, Taechung, Kwangmyong, Yang-gok, Uihui, Chohae, Haenggan. Less busy points of it are Oyo, Kuhu, Sungup, Konmyong, Konmyongl, Konmyong2, Sangmyong, SanghaChongmyong, Shinmyong, Osang, Shinjong, Yonghyang, Yaemyong, Chon-yu, Chon-ju, Kwallye, Naebi, Noeho, Tuyu, Mokchang, Ponshin, Shinhoe, Yepung, Okchim, Pungbu, Kokchon, Kollyun, Nae-gwan, Tae-nung, Samumgyo, Sokolkong, Shinsu, Um-gyo, Igan, Chongok, Choktaek, Kyonjungsu, Kokchi, Kongchoe, Kyuum, Kihae, Taekolkong, Taedon, Pino, Pisu, Sabong, Samgan, Kokchi, Shinmun, Shinmaek, Shimsu, Yangno, Aengmun, Yolgyol, Oegwan, Wijung, Chang-gan, Chungjo, Chungdo, Chigu, Chium, Chollyo, Tongni, Pungmun, Haryom. Very busy points of ear-acupuncture are Kan, Bi, Shin, An, Less busy points of it are Shim, Pye, Naebunbe, Mok1, Mok2, Shinmun, Ichom. Useful points of bleeding by needle are Taeyang meridian, Yangmyong meridian, Chono, Chonjong, Paekoe, Sangsong, Chanjuk, Sajukkong, nasal cavity. Useful points of moxibustion are Inchung, Huaryo, Shinchu, Pungmun, Kansu, Shimsu, Kokchi, Kongchoe, Sohae.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1128-1132
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• 2014

A kinetic study on aminolysis of 4-chloro-2-nitrophenyl X-substituted-benzoates (6a-i) in MeCN is reported. The Hammett plot for the reactions of 6a-i with piperidine consists of two intersecting straight lines, while the Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}_X$ = 1.03 and r = 0.78. The nonlinear Hammett plot is not due to a change in rate-determining step (RDS) but is caused by the resonance stabilization of substrates possessing an electron-donating group in the benzoyl moiety. The Br${\phi}$nsted-type plot for the reactions of 4-chloro-2-nitrophenyl benzoate (6e) with a series of cyclic secondary amines is linear with ${\beta}_{nuc}$ = 0.69, an upper limit for reactions reported to proceed through a concerted mechanism. The aminolysis of 6e in aqueous medium has previously been reported to proceed through a stepwise mechanism with a change in RDS on the basis of a curved Br${\phi}$nsted-type plot. It has been concluded that instability of the zwitterionic tetrahedral intermediate ($T^{\pm}$) in MeCN forces the reaction to proceed through a concerted mechanism. This is further supported by the kinetic result that the amines used in this study are less reactive in MeCN than in $H_2O$, although they are more basic in MeCN over 7 $pK_a$ units.

• Korean Journal of Acupuncture
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• v.27 no.3
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• pp.57-65
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• 2010

Objectives : The purpose of this study is to investigate for rhinitis of middle school students and to confirm the effect of oriental medical treatments on rhinitis. We proceeded with this oriental medical treatment programs in collaboration with community health center. Methods : We have given oriental medical treatment, such as herbal medicines(pillet type Gamisinicheongpye-um and ointment) and intradermal acupuncture therapy at Hapgok (LI4), Yeonghyang (LI20), Indang, Bi-ik points, to patients for 9 weeks. Results of this treatment program were evaluated on a 4-point-scale depends on symptoms ; 'severe ()', 'moderate (++)', 'mild (+)' and 'no symptom (-)'. Results : After oriental medical treatments, rhinitis symptoms (sneezing, rhinorrhea, nasal obstruction, nasal itching and dysosmia) were improved significantly compared to before treatments (p<0.05). Conclusions : We confirmed rhinitis treated with oriental medicine should significant improvement and suggest that it is necessary to expand oriental medical treatment programs in collaboration with community health center.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1929-1940
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• 1999

In this paper a VLSI design for the automatic magnetizing and inspection system has been presented. This is a design of a peripheral controller, which magnetizes CRTs and computer monitors and controls the automatic inspection system. We implemented a programmable peripheral interface(PPI) circuit of the control and protocol module for the magnetizer controller by using a 0.8um CMOS SOG technology of ETRI. Most of the PPI functions have been confirmed. In the conventional method, the propagation/ramp delay model was used to predict the delay of cells, but used to model on only a single cell. Later, a modified "linear delay predict model" was suggested in the LODECAP(LOgic DEsign CAPture) by adding some factors to the prior model. But this has not a full model on the delay chain. In this paper a new " delay predict equation" for the design of the timing control block in PPI system has been suggested. We have described the detail method on a design of delay chain block according to the extracted equation and applied this method to the timing control block design. And we had descriptions on the other blocks of this system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.84-87
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• 2005

본 논문에서는 p-type 고분자 물질인 P3HT (Poly-3-hexylthiophene)를 잉크젯 프린팅 방식으로 활성화층을 적층함으로써 Organic thin film transistor를 제작하여 이에 대한 특성을 연구하였다. Piezoelectric 방식의 잉크젯 프린팅을 이용하여 P3HT single drop jetting 시 두께 $150{\sim}200{\AA}$, 직경 약 70 ~ 80 um정도의 drop profile을 얻을 수 있었다. P3HT의 solvent로서 Chlorobenzene을 사용하여 농도 약 0.5 wt.%의 Ink-jet용 ink를 제작하여 이를 Channel Width 37, 236 um 크기의 Au 전극 위에 jetting 하여 각각의 특성을 측정하였다. 상기 실험은 상온의 외부환경에서 실시되었으며 실험 결과 최대 ${\mu}=1{\times}10^{-2}\;cm^2/Vsec$, $I_{on}/I_{off}=10^3{\sim}10^4$ 정도로서 off current가 높은 편이나 이동도 측면에서는 다른 방법의 박막 증착 실험결과와 비교할 때 동등 수준의 결과를 얻을 수 있었다.