• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
• /
• pp.505-508
• /
• 2004

Gate length dependent data of intrinsic MOSFET equivalent circuit parameters are extracted using a direct extraction technique based on simple 2-port parameter equations. The relatively scalable data with respect to gate length are obtained. These data are verified to be acrurate by observing good correspondence between modeled and measured S-parameters up to 30GHz. These data will be helpful to construct RF scalable MOSFET model.

• 한국분무공학회지
• /
• 제4권2호
• /
• pp.47-52
• /
• 1999

The prediction of the critical Reynolds number in the stability curie of liquid jet was mainly analyzed by the empirical correlations and the experimental data through the literature. The factors affecting the critical Reynolds number include Ohnesorge number, nozzle length-diameter ratio, ambient pressure and nozzle inlet type. The nozzle inlet type was divided into two groups according to the dependence of the critical Reynolds number on the length-to-diameter ratio of nozzle. The empirical correlations for the critical Reynolds number as a function of above factors mentioned are newly proposed.

• Bulletin of the Korean Chemical Society
• /
• 제34권12호
• /
• pp.3790-3794
• /
• 2013

Molecular dynamics simulations were performed to study the structure and stability of a nanoscale self-assembled monolayer (SAM) of alkanethiol on a gold (111) surface. The tilt angle and orientational order of the alkyl chains in the SAM island were examined by systematically varying the size of the island. The chain length dependence of the SAM island was examined by considering alkanethiols containing 12, 16, 20, and 24 carbon atoms. The minimum diameter of SAM islands made from 1-tetracosanethiol, 1-ecosanethiol, 1-hexadecanethiol and 1-dodecanethiol were 2.29, 1.9, 4.7 and 4.76 nm, respectively. These set the ultimate resolution that can be patterned by soft nanolithography. As the length of alkanethiol increases, the SAM islands became more ordered in both orientation and conformation of the alkyl chains.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
• /
• pp.243-246
• /
• 2006

This study investigates the improvement in the theoretical success rate of the integer ambiguity resolution in GPS/GNSS carrier-phase positioning by using many visible satellites. It estimates the dependence of the rate on the baseline length in relative positioning under the condition of the use of double/triple-frequency navigation signals. The calculation results show that the use of 14 navigation satellites (i.e., seven GPS and seven Galileo ones) remarkably improves the success rate under the condition of very short baseline length, compared with the use of seven GPS ones. The numerical reliability of the calculated success rates is strictly tested by examining the tightness of the union and minimum-distance bounds to the rate. These bounds are also shown to be effective to investigate the realization of the high success rates.

• 생물정신의학
• /
• 제12권2호
• /
• pp.196-206
• /
• 2005

Objectives:The purpose of this study is to evaluate the pathophysiology of alcoholics by investigating the differences in frequency of Aldehyde Dehydrogenase 2(ALDH2) genotypes and ALDH2 alleles between patients with alcohol dependence and controls, and the differences of drinking and personality traits in Korean male alcoholics with ALDH2 genotype variances. Methods:The authors selected 98 patients with alcohol dependence and 53 controls. Self-report questionnaires for acute reponses after alcohol ingestion, the AUI(Alcohol Use Inventory), and the NEO-PI-R(NEO Personality Inventory Revised) were given to all patients with alcohol dependence. ALDH2 genotypes were typed with MboII RFLP(Restriction Fragment Length Polymorphism) method in 53 controls and 98 patients with alcohol dependence. The authors divided alcoholic patients into two groups according to the presence of variant $ALDH2^2$ allele;normal ALDH2 alcoholics(N=87) and variant ALDH2 alcoholics(N=11). Results:1) The genotypic frequencies of subjects with $ALDH2^{1/1}$ were higher and those with $ALDH2^{1/2}$ and $ALDH2^{2/2}$ were lower in patients than in controls. 2) Alcohol dependence could be found in $ALDH2^{2/2}$ homozygote individuals. 3) Variant ALDH2 alcoholics had more family problems in the AUI than normal ALDH2 alcoholics. 4) Variant ALDH2 alcoholics experienced more flushing and cardiovascular responses after alcohol ingestion than normal ALDH2 alcoholics. 5) Variant ALDH2 alcoholics had less altruistic personality traits in the NEO-PI-R than normal ALDH2 alcoholics. 6) Variant ALDH2 alcoholics tended to have more tolerance to alcohol than normal ALDH2 alcoholics. Conclusion:Variant $ALDH2^2$ allele might play a protective role in the pathogenesis of alcohol dependence and there were several significant differences of drinking and personality traits in Korean male alcoholics with ALDH2 genotype variances.

• 한국전자파학회논문지
• /
• 제15권5호
• /
• pp.517-524
• /
• 2004

광 위상 공액기(OPC: Optical Phase Conjugator)가 전체 전송 거리의 중간이 아닌 곳에 위치한 8-채널 WDM 시스템에서 두 전송 구간의 총 분산량 변동에 따른 각 채널의 보상 특성을 NRZ 형식과 RZ 형식별로 살펴보았다. 신호파를 공액파로 만드는 OPC의 비선형 매질로는 광대역 특성을 나타낼 수 있는 HNL-DSF(Highly- Non-linear Dispersion Shifted Fiber)를 사용했다. 우선 OPC를 중심으로 두 전송 구간의 총 분산량이 서로 동일하지 않은 WDM 전송 시스템에서는 전송 파형 형식으로 NRZ보다 RZ를 사용한 경우가 안정된 품질 유지에 더욱 유리하다는 것을 확인하였다. 또한 NRZ 파형 전송의 경우 OPC를 중심으로 두 전송 구간의 총 분산량을 동일하게 설정하는 것보다 상대적으로 길이가 짧은 전송 구간의 총 분산량을 길이가 긴 전송 구간의 총 분산량에 비해 작게 설정하여야 양호한 보상이 이루어지는 것을 확인하였다.

• 대한기계학회논문집B
• /
• 제21권3호
• /
• pp.445-456
• /
• 1997

Continuous casting process is numerically analyzed using the continuum model in a non-orthogonal coordinate system. Flow damping in the mush is modeled by combining the viscosity dependence on liquid fraction in dilute mush and the permeability dependence on liquid fraction in concentrated mush. The effect of turbulence is indirectly considered by effective diffusivity determined elsewhere by experiment. The main objective is to investigate the effects of casting parameters such as casting speed and tundish superheat on the distribution of surface temperature, shell thickness, metallurgical length and centerline segregation. Some of the computed results are compared with available experiments, and reasonable agreements are obtained.

• 소성∙가공
• /
• 제16권2호
• /
• pp.101-106
• /
• 2007

Uniaxial displacement controlled tests were performed on annealed Type 304 stainless steel at room temperature. A servo-controlled testing machine and strain measurement on the gage length were employed to measure the response to a given input. The test results exhibit that the flow stress increases nonlinearly with the strain rate and the relaxed stress at the end of the relaxation periods depends strongly on the strain rate preceding the relaxation test. The rate-dependent inelastic deformation behavior is simulated using a new unified viscoplasticity model that has the rate-dependent format of nonlinear kinematic hardening rule, which plays a key role in modeling the rate dependence of relaxation behavior. The model does not employ yield or loading/unloading criteria and consists of a flow law and the evolution laws of two tensor and one scalar-valued state variables.

• Journal of the Optical Society of Korea
• /
• 제12권1호
• /
• pp.57-61
• /
• 2008

We investigated the laser pulse-width dependence of dense plasmas confined within the magnetic length of $In_{0.2}Ga_{0.8}As$/GaAs multiple quantum wells under high magnetic fields up to 31 T. To fully fill the Landau levels of effectively zero-dimensional system, we used intense femtosecond (fs) laser pulses to create carrier densities near $10^{13}/cm^2$. The observed photoluminescence showed a characteristic of superfluorescence, above critical magnetic field when being excited by pulses shorter than coherence buildup time.

• 복식문화연구
• /
• 제2권2호
• /
• pp.355-369
• /
• 1994

The purpose of this study was to investigate the relationship between the social values and selected clothing behavior variable for a group of working women in Kwang Ju, Chonnam, Korea. The findings of this study as follows: 1. The were differences in selective clothing variables according to their general characteristics; age, marital status, religion. 2. There were differences in selective clothing variables according to their occupational characteristics; type, length of employment, income. 3. A significant relationship was found between he social values and selected clothing behavior variables; There were significant relationship between the social trend and five clothing behavior variables; social approval, psychological dependence, satisfaction, comfort, interest. There ere significant relationship between the human relation and one clothing variables; management. There were significant relationship between the popularization and three clothing behavior variables; social approval, psychological dependence and management.