• 전기전자학회논문지
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• 제2권2호
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• pp.278-284
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• 1998

본 논문에서는 HDTV 응용을 위한 10b 저전력 CMOS A/D 변환기 (analog-to-digital converter : ADC) 회로를 제안한다. 제안된 ADC의 전체 구조는 응용되는 시스템의 속도와 해상도 등의 사양을 고려하여 다단 파이프라인 구조가 적용되었다. 본 시스템이 갖는 회로적 특성은 다음과 같이 요약할 수 있다. 첫째, 전원전압의 변화에도 일정한 시스템 성능을 얻을 수 있는 바이어스 회로의 선택적 채널길이 조정기법을 제안한다. 둘째, 고속 2단 증폭기의 전력소모를 줄이기 위하여 증폭기가 사용되지 않는 동안 동작 전류 공급을 줄이는 전력소모 최적화 기법을 사용한다. 넷째, 다단 파이프라인 구조에서 최종단으로 갈수록 정확도 및 잡음 특성 등에서 여유를 얻을 수 있는 점을 고려한 캐패시터 스케일링 기법의 적용으로 면적 및 전력소모를 감소시킨다. 제안된 ADC는 0.8 um double-poly double-metal n-well CMOS 공정 변수를 사용하여 설계 및 제작되었고, 시제품 ADC의 성능 측정 결과는 Differential Nonlinearity (DNL) ${\pm}0.6LSB$, Integral Nonlinearity (INL) ${\pm}2.0LSB$ 수준이며, 전력소모는 3 V 및 40 MHz 동작시에는 119 mW, 5 V 및 50 MHz 동작시에는 320 mW로 측정되었다.

• 한국진공학회지
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• 제6권S1호
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• pp.110-114
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• 1997

Development of metal ion source growth of high quality Cu metal film formation of non-stoichiometric $SnO_2$ films of Si(100), and modification fo polymer surface by low enregy ion beam have been carried out at KIST Ion Beam Lab. A new metal ion source with high ion beam flux has been developed by a hybrid ion beam (HIB) deposition and non-stoichiometric $SnO_2$ films are controlled by supplying energy. The ion assisted reaction (IAR) in which keV ion beam is irradiated in reactive gas environment has been deveolped for modifying the polymers and enhancing adhesion to other materials and advantages of the IAR have been reviewed.

• Asian-Australasian Journal of Animal Sciences
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• 제11권1호
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• pp.55-59
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• 1998

To study the effect of induced hypothyroidism on fertility status of male Black Bengal goats, 10 adult healthy mature males were divided into control and treated groups. Hypothyroidism was induced successfully by injecting thiourea subcutaneously initially for 15 days at the rate of 100 mg/kg body weight, followed by 66.7 mg/kg body weight for the subse quent 15 days. This resulted in a decrease (p < 0.01) in plasma tri-iodothyronine, thyroxine and testosterone levels, with increasing duration of thiourea treatment. It also adversely affected semen quality, ejaculate volume, sperm concentration, motility and viability. Live percentage declined to 75% for treated and control remained at 90%. Artificial insemination fo female goats with semen of thiourea-treated goats, resulted in failure of conception. However, females inseminated with semen of male goats of control group showed 100% conception. These observations indicate that, thyroid hormones play a key role in maintaining the normal reproductive processes of male goats.

• Geomechanics and Engineering
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• 제16권1호
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• pp.71-83
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• 2018

Compacted bentonites were chosen as the backfill material and buffer in high level nuclear waste disposal due to its high swelling pressure, high ion adsorption capacity and low permeability. It is essential to estimate the swelling pressure in design and considering the safety of the nuclear repositories. The swelling pressure model of expansive clay colloids was developed based on Gouy-Chapman diffuse double layer theory. However, the diffuse double layer model is effective in predicting low compaction dry density (low swelling pressure) for certain bentonites, and invalidation in simulating high compaction dry density (high swelling pressure). In this paper, the new relationship between nondimensional midplane potential function, u, and nondimensional distance function, Kd, were established based on the Gouy-Chapman theory by considering the variation of void ratio. The new developed model was constructed based on the published literature data of compacted Na-bentonite (MX80) and Ca-bentonite (FoCa) for sodium and calcium bentonite respectively. The proposed models were applied to re-compute swelling pressure of other compacted Na-bentonites (Kunigel-V1, Voclay, Neokunibond and GMZ) and Ca-bentonites (FEBEX, Bavaria bentonite, Bentonite S-2, Montigel bentonite) based on the reported experimental data. Results show that the predicted swelling pressure has a good agreement with the experimental swelling pressure in all cases.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.402-403
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• 2018

차량용 근거리레이다에서 사용하는 70GHz대역 고이득 배열안테나를 설계하고 제작하였다. 근거리 레이다에서는 분해능을 높이기 위해서 이득이 높아야 하며 FoV(Field of View)를 확보하기 위한 Angle Width를 가져야 한다. 제안된 안테나는 76~81GHz에서 동작하며 Angle width $60^{\circ}$, 안테나이득 15dB 이상을 만족하고 동작주파수내에서 입력반사계수 -10dB 이하의 성능을 갖는다. 안테나의 측정을 위하여 Wave guide WR-10을 사용하였고 측정결과 시뮬레이션과 유사한 결과를 얻었다.

• 간호행정학회지
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• 제17권4호
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• pp.474-483
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• 2011

Purpose: This study was conducted to identify factors affecting nurses' burnout in secondary general hospitals. Methods: Data were collected through structured questionnaires from 241 nurses working at the secondary general hospitals with below 400 beds in the P, C, and S city between April and May, 2009. Data analysis was done with independent t test, ANOVA, Pearson correlation coefficient, and multiple stepwise multiple regression with SPSS WIN v 17.0. Results: Burnout was significantly different according to religion, age, clinical experiences, and shift work. Burnout score of the subjects was 58/100. Burnout of the subjects were positively correlated with job stress and negatively correlated with hardness, self efficiency, self esteem, spiritual wellbeing, social support, and job satisfaction. The explained variances for burnout was 51.8% and factors affecting nurses' burnout in secondary general hospitals were job stress, hardness, self efficiency, job satisfaction and shift work. Conclusion: These results showed the significant factors fo nurses' burnout in secondary general hospitals. These findings can be utilized to development of strategies for reducing job stress and enhancing hardness, self efficiency and job satisfaction.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1516-1518
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• 1998

$YBa_2Cu_3O_x$(Yl23) Superconducting thick films on $Y_2BaCuO_5$(Y211) substrate were Prepared by surface diffusion process between $BaCuO_2$+CuO composite coating powder and a Y2ll substrate. X-ray diffraction shows that the Yl23 layer onto Y2ll substrate is the orthorhombic crystal structure. The specimen heated at $940^{\circ}C$ for 2h showed the maximum $J_c$ fo 500A/$cm^2$. Based on optimal condition, the superconducting fault current limiter(FCL) having a current limiting area 1mm wide and 66mm long was fabricated on Y211 substrate. A typical current limiting waveform was measured. When a voltage of 3V was applied, the fault current with a peak of 15A was limited to about 0.11A.

• 산업기술연구
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• 제3권
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• pp.17-26
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• 1983

The blast vibrations were measured from 10 places through Seoul subway area to study their effects on the structures and to establish the safe blasting limits. For purpose of the present study, particle velocity only was recorded and analyzed, because it correlated most directly with damage. The results are as follows: (1) The proagation equation, $V=K(D/W^{1/3})^{-n}$ was obtained. Typical values could be found for n range from 1.7 to 1.5 and for k range from 48 to 138. (2) From the relationship between schmidt hammer rebound hardness and uniaxial compressive strength, $Sc=0.514{\times}(S.H)^{0.23}$, the compressive strength at any area can be assumed. (3) The use of AN-FO and other explosives with low detonation pressure may reduce vibration levels generated.

• 대한후두음성언어의학회지
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• 제9권1호
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• pp.47-52
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• 1998

Objectives : To compare the objective differences in voice quality and voice problems between clergies and normal male control group. Materials and Methods : The sustained vowel sound of 46 clergies and 40 normal persons were analyzed, using a videostroboscopy and acoustic analyzer. Together with these analyses, a questionnaire associated with current and past voice problems was handed over to the patients. Results : The most common symptom in subjective group was the voice fatigue. Stroboscopic findings in subjective group were as following 23 cases(50%) of pachydermia, 17 cases(37%) of phase difference, 12 cases(25%) of anterior-posterior contracture, 6 cases(13%) of vocal polyp and 3 cases(7%) of vocal nodule. The mean maximal phonation time in clergies was 17.8 seconds and in control group was 19 seconds. litter, pitch perturbation quotient and shimmer were significantly increased in subjective group than in control group(p<0.05), but there were no significant differences between two groups in fundamental frequency, vFo, amplitude perturbation quotient and noise to harmonic ratio. Conclusion : In the clergies using loud and forceful voice, vocal polyp and functional voice disorder findings were frequently noted in stroboscopic examination. litter and shimmer, reflecting the roughness of voice, were increased in acoustic analysis. Therefore, clergies, classified into untrained professional voice users, need professional career guidance and counseling.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권4호
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• pp.395-404
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• 2016

A 6-bit 3.4 GS/s flash ADC in a 65 nm CMOS process is reported along with the proposed 4x time-domain interpolation technique which allows the reduction of the number of comparators from the conventional $2^N-1$ to $2^{N-2}$ in a N-bit flash ADC. The proposed scheme effectively achieves a 4x interpolation factor with simple SR-latches without extra clocking and calibration hardware overhead in the interpolated stage where only offset between the $2^{N-2}$ comparators needs to be calibrated. The offset in SR-latches is within ${\pm}0.5$ LSB in the reported ADC under a wide range of process, voltage supply, and temperature (PVT). The design considerations of the proposed technique are detailed in this paper. The prototype achieves 3.4 GS/s with 5.4-bit ENOB at Nyquist and consumes 12.6 mW power at 1 V supply, yielding a Walden FoM of 89 fJ/conversion-step.