• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.243.1-243.1
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• 2016

Recently, many groups have attempted to fabricate 3-dimensional (3D) structures of GaN such as pyramids, rods, stripes and annulars. Since quantum structures on non-polar and semi-polar planes of 3D structures have less influence of internal electric filed, multi quantum wells (MQWs) formed on those planes have high quantum efficiency. Especially, pyramidal and annular structures consist of various crystal planes with different emission wavelength, providing a possibillity of phosphor-free white light emtting diodes (WLEDs).[1] However, it still has problem to obtain high color rendering index (CRI) number because of narrow-band emission and poor indium composition caused by the formation of few number of facets during metal-organic chemical vapor deposition growth.[2] If we can fabricate 3D structure having more various facets, we can make broad-band emittied WLEDs and improve CRI number. In this study, we suggest a simple method to fabricate 3D structures having various facet and containing high indium composition by means of a combination of metal-organic chemical vapor deposition and wet chemical etching techniques.

• 마이크로전자및패키징학회지
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• 제12권1호
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• pp.73-76
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• 2005

To widen the band gap of ZnO, we have investigated $Zn_{1-x}Mg_xO(ZMO)$ thin films prepared by pulsed laser deposition on c-plane sapphire substrates at $500^{\circ}C$. From X-ray diffraction patterns, ZMO films show only the (0002) and (0004) diffraction peaks. It means that the flints have the wurtzite structure. Segregation of ZnO and MgO phases is found in the films with x=0.59. All the samples are highly transparent in the visible region and have a sharp absorption edge in the UV region. The shift of absorption edge to higher energy is observed in the films with higher Mg composition. The excitonic nature of the films is clearly appeared in the spectra for all alloy compositions. The optical band-gap ($E_g$) of ZMO films is obtained from the ${\alpha}^2$ vs Photon energy plot assuming ${\alpha}^2\;\propto$ (hv - $E_g$), where u is the absorption coefficient and hv is the photon energy. The value of $E_g$ increases up to 3.72 eV for the films with x=0.35. It is important to adjust Mg composition control for controlling the band-gap of ZMO films.

• 한국전기전자재료학회논문지
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• 제22권8호
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• pp.677-681
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• 2009

$In_xGa_{1-x}N$ alloys with 20-nm-thickness were deposited onto Mg:GaN/AlN/SiC substrates by MOCVD at $800\;^{\circ}C$. TMGa, TMIn and $NH_3$ were used as the precursor of gallium, indium and nitrogen, respectively. The mole ratio of indium in $In_xGa_{1-x}N$ films varied between 0 and 0.2. The energy-band-gaps of the films were obtained from the photoluminescence and cathodoluminescence peaks. The mole ratios of $In_xGa_{1-x}N$ films were calculated by applying Vegard's law to XRD results. The energy-band-gap versus indium composition plot for $In_xGa_{1-x}N$ alloys were well fit with a bowing parameter of 2.27.

• 한국재료학회지
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• 제12권11호
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• pp.875-879
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• 2002

$Pb_{1-x}$ $Cd_{x}$ $I_2$ (x=0.0, 0.2, 0.5, 0.7, 0.9, 1.0) single crystals were grown by using Bridgman method and their structural and optical properties were investigated from the measurement of X-ray diffraction, optical absorption and photoluminescence. As-grown single crystals have hexagonal closed packed layered structure. The values of lattice constant c decrease with increasing composition x. Direct and indirect transition optical energy band gaps are calculated from optical absorption spectra measured at room temperature. They increase exponentially from 2.3eV to 3.2 eV with increasing composition x. The energies of photoluminescence peak due to donor bound exciton measured at 6K increase with increasing composition . However, the peak energies of donor-acceptor pair (DAP) are independent of the optical energy band gaps of $Pb_{1-x}$/$Cd_{x}$ $I_2$ single crystals.

• 대한전자공학회논문지SD
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• 제44권3호
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• pp.26-34
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• 2007

본 논문에서는 신체 임피던스 측정법(Bioelectrical Impedance Analysis, 이하 BIA)을 기초로 한 체지방 측정 칩 설계에 대한 내용을 서술하였다. 제안된 회로는 인체에 전류 신호를 인가하는 회로, 인체를 통해 나온 전압 신호를 측정하는 회로, 회로의 동작을 제어하는 마이크로 콘트롤러(Micom), 그리고 분석프로그램이 내장된 메모리(SRAM, EEPROMs) 의 모든 기능을 하나의 칩에 집적하였다. 특히 정밀한 인체 임피던스 측정을 위하여 다주파수 동작이 가능한 대역통과필터(Band Pass Filter, BPF)를 설계하였다. 또한, 설계된 대역통과필터는 weak inversion 영역에서 동작하기 때문에 면적과 전력소모를 줄일 수 있었다. 그리고 측정부분 회로의 성능을 개선하기 위해서 차동차이증폭기(Differential difference amplifier, DDA)를 이용한 새로운 전파정류기(Full wave rectifier, FWR)를 설계하였다. 또한 이 회로는 마지막 단에 연결될 아날로그-디지털 변환기(ADC)의 설계에 대한 부담을 덜어주는 장점도 있다. 이 칩의 시제품은 CMOS 0.35um 공정을 이용하였고 전력소모는 모든 주파수에서 6mW 이며 전원전압은 3.3V이다. 전체 칩의 크기는 $5mm\times5mm$ 이다.

• 대한통합의학회지
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• 제8권2호
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• pp.109-119
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• 2020

Purpose : The purpose of this study was to investigate the effects of a combined exercise program using a ballet bar and elastic bands on the body composition, physical strength, and postural correction of middle-aged women. Methods : The subjects were 28 middle-aged women with no ballet experience. They were divided into an experimental group (n=14; exercise group) and a control group (n=14; non-exercise group) through random sampling. The experimental group underwent an exercise program using a ballet bar and elastic bands for 50 minutes twice a week for 12 weeks, whereas the control group performed no exercise. The subjects in both group had their body composition, physical fitness, and postural angles measured before and after the intervention. A paired t-test was used to compare pre- and post-test values within each group, and a two-way repeated measures ANOVA was employed to compare pre- and post-test changes between the two groups. Results : Regarding body composition, statistically significant differences in BMI (p<.05), body fat percentage (p<.001), and muscle mass (p<.001) were observed between the two groups before and after the intervention. For physical fitness, the experimental group showed statistically significant increases in quick reflexes (p<.001), muscle endurance (p<.001), and muscle strength (p<.001). For postural correction, the experimental group exhibited statistically significant decreases in all variables: the head (p<.001), shoulder (p<.001), cervical tilt (p<.001), right-left pelvic tilt (p<.001), and anterior-posterior pelvic tilt (p<.001). Conclusion : A combined exercise program using a ballet bar and elastic bands had positive effects on the body composition, physical fitness, and postural correction of middle-aged women.

• 제어로봇시스템학회논문지
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• 제12권5호
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• pp.438-443
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• 2006

In this paper, We had proposed SDR module, and designed FPGA to compose with channel separation of broadband CDMA signal what have multiple FA. At decomposition and composition process of multiple FA CDMA signal, system only progress decomposition and composition of channel selected by software. Therefore, proposed system can manage base station transceiver system very effectively than the other way what send on all band of multiple CDMA signal. Also, it is possible that system sets again coefficient of each filter because it is consisted of SDR module. Therefore, we can easily control coefficient each filter according to base station transceiver system environment.

• BMB Reports
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• 제33권6호
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• pp.510-513
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• 2000

Boar sperminogen was purified from the acid extracts of the washed epididymal spermatozoa by gel filtration through a Sephadex G-100 column, followed by preparative SDS-PAGE. The 32 kDa sperminogen band was sliced out from the preparative SDS-PAGE and 32 kDa sperminogen was eluted from the gel matrix. The purified 32 kDa sperminogen was subjected to amino acid composition analysis. The amino acid composition of the 32 kDa boar sperminogen showed significant differences from that of either boar proacrosin or ${\beta}-acrosin$, which signifies that 32 kDa sperminogen might not be a breakdown product of proacrosin-acrosin system and that the 32 kDa sperminogen is a different protein from proacrosin-acrosin system.

• The Korean Journal of Ceramics
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• 제3권2호
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• pp.139-143
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• 1997

The photoluminescence characteristics of the zinc gallate have been investigated as a function of the composition and the firing atmosphere. Two distinct emission bands were observed whose peaks are 360 nm and 430 nm respectively. These emission bands are considered to be from two different emission centers. For $ZnO/Ga_2O_3$=49.3/50.7 or higher, 430 nm band is predominant and for $ZnO/Ga_2O_3$=49.2/50.8 or lower, 360nm band becomes predominant, whereas 430 nm band is almost completely suppressed. The shift of emission peak is though to be due to the change of the cation distribution with the zinc content in the spinel zinc gallate. Also, the emission centers responsible for the 360nm band are considered to be more efficient energy absorbers than the ones for the 430 nm band. Highly efficient green emitting phosphor was obtained by activating Zn-deficient zinc gallate with manganeses.

• 한국식품과학회지
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• 제10권1호
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• pp.83-87
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• 1978

한국산 호박씨중에서 지방(脂肪)을 추출하여 지방산(脂肪酸)의 종류를 조사하였고 또한 물에 가용(可溶)인 단백질(蛋白質) 및 불용성(不溶性) 단백질(蛋白質)을 분리(分離)하여 Disc 전기영동으로 단백질의 Pattern을 확인하고 아미노산 조성(組成)을 관찰하였다. 1. 호박씨의 일반성분중 지방은 46.5% 단백질 25.5%를 함유하고 있다. 2. 호박씨기름의 지방산(脂肪酸) 조성(組成)은 linoleic acid 51.74%, oleic acid 22.2%, palmitic acid 18.1%, stearic acid 7.84%로 이들 4가지를 주 지방산으로 하고 있다. 3. 호박씨 단백질(蛋白質)의 아미노산(酸) 조성(組成)은 tyrosine, glutamic acid, aspartic acid, leucine, glycine등을 다량(多量) 함유하고 있으나 함황(含黃) 아미노산(酸)은 함유(含有)하고 있지 않다. 4. 단백질의 Disc전기영동 결과 가용성(可溶性) 단백질(蛋白質)에서 13개의 band와 불용성(不溶性) 단백질에서 4개의 band가 분리 되었다.