• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
• /
• pp.288-292
• /
• 2006

Usually, equations that calculate ground resistance of earth electrode was already informed well by form of earth electrode. But, when apply on the spot because general expressions are very insufficient at point that calculate exact ground resistance value by variation of earth electrode, and constant value that corrective coefficient for ground resistance calculation is fixed regardless of change of the earth resistivity specially is presented, it is actuality that difficulty is. Therefore, in this study, about these problem, proposed corrective coefficient for calculation of ground resistance according to change of the earth resistivity.

• 한국군사과학기술학회지
• /
• 제4권1호
• /
• pp.264-273
• /
• 2001

The conjugate heat transfer from a protruding module in a horizontal channel with a variation of air temperature is experimentally investigated. It is an aim of this study is to estimate temperature difference between a module and air. This study is performed with a variation of parameters that are air temperatures($T_i,=25^{\circ}C{\sim}55^{\circ}C),$ thermal resistance($R_c=158 K/W),$ air velocities ( 4V_i=0.1$ m/s~l.5 m/s ), and input power (Q=3 W, 7 W ). The results show that as the thermal resistance increases, the effect of air temperatures are decreased. And input power was most effective parameter on the temperature difference between a module and air.

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 1995년도 Proceedings of special lectures on Molecular Biological Approaches to Plant Disease National Agricultural Science and Technology Institute Suwon, Korea
• /
• pp.21-25
• /
• 1995

;Bacterial blight caused by Xanthomonas oryzae pv. Olyzae is one of the most important diseases of rice. Host resistance, which relies on single, dominant resistance genes, is the only reliable method to control the disease at present. Pathogenic variation of the bacteria has been shown to follow the deployment of resistance genes in commercial cultivars. Information on the factors and the mechanisms for genetic variation of this pathogen is limited. Further, we have no clear evidence of whether population variability is due to sexual recombination or to variation introduced by mutations or intragenic recombination in a clonally maintained population.(omitted)itted)

• 한국전기전자재료학회논문지
• /
• 제22권2호
• /
• pp.119-122
• /
• 2009

As infrared light radiates, the CMOS Readout IC (ROIC) for the microbolometer typed infrared sensor detects voltage or current which is caused by the variation of resistance in the bolometer sensor. A serious problem we may have in designing the ROIC is the value of bolometer and reference resistors will be changed due to process variation. Since each pixel does not have the same value of resistance, fixed pattern noise problems happen during the sensor operations. In this paper, we propose a novel technique to compensate the fluctuation of reference resistance with taking account of process variation. By using a comparator and a cross coupled latch, we will make the value of reference resistor same as the bolometer's.

• 전력전자학회논문지
• /
• 제3권3호
• /
• pp.206-213
• /
• 1998

본 논문에서는 유도전동기의 속응 토크제어를 위한 파라미터 변동의 적응보상기법을 제안하였다. 제어성능을 현저히 저하시키는 원인으로 작용하는 파라미터의 변동을 보상하기 위하여 본 논문에서는 모델기준 적응제어(MRAC)방식을 적용하여 회전자 저항값 변동을 추정 보상한다. 본 적응제어방식은 실측 순시무효전력과 추정 순시무효전력의 오차관계에서 실시간으로 회전자 저항값 변동을 추정 보상하는 방식이다. 본 방식은 전동기 파라미터를 사용하지 않고 실측 순시무효전력을 기준모델로 적용하기 때문에 전동기 등 등가모델에서 구한 기존의 다른 기준모델에 비해 강인한 시스템이 된다. 추정된 회전자 저항값을 이용하여 자속관측기를 구성하고 이를 직접베터 제어방식에 적용하였으며, 시뮬레이션 및 실험을 통하여 속응 토크제어가 원활히 수행됨을 입증하였다.

• 한국해양공학회지
• /
• 제22권5호
• /
• pp.83-86
• /
• 2008

This paper deals with the experimental works for the correlations of ice resistance for icebreaker with synthetic(model) ice in general towing tank and with refrigerated ice in ice tank. In order to find out the correlation, the density variation is mainly focused in the present study. The model of Terry-Fox ice breaker has been used for the present correlation study because many data are available to be compared. According to the increase of density, the correlation becomes better quantitatively as well as qualitatively. Other parametric studies such as an ice size, a friction coefficient, a bending moment, etc., are also expected to be carried out to have better correlation in a near future. This research could be the basis for the possibility of resistance test using a synthetic ice in a general towing tank instead of an expensive ice tank.

• Transactions on Electrical and Electronic Materials
• /
• 제9권3호
• /
• pp.101-104
• /
• 2008

The electrical properties and microstructure of nitrogen-doped poly 3C-SiC films were studied according to different thickness. Poly 3C-SiC films were deposited by LPCVD(low pressure chemical vapor deposition) at $900^{\circ}C$ and 4 Torr using $SiH_2Cl_2$ (100 %, 35 sccm) and $C_2H_2$ (5 % in $H_2$, 180 sccm) as the Si and C precursors, and $NH_3$ (5 % in $H_2$, 64 sccm) as the dopant source gas. The resistivity of the 3C-SiC films with $1,530{\AA}$ of thickness was $32.7{\Omega}-cm$ and decreased to $0.0129{\Omega}-cm$ at $16,963{\AA}$. In XRD spectra, 3C-SiC is so highly oriented along the (1 1 1) plane at $2{\theta}=35.7^{\circ}$ that other peaks corresponding to SiC orientations are not presented. The measurement of resistance variations according to different thickness were carried out in the $25^{\circ}C$ to $350^{\circ}C$ temperature range. While the size of resistance variation decreases with increasing the films thickness, the linearity of resistance variation improved.

• Computers and Concrete
• /
• 제13권2호
• /
• pp.255-270
• /
• 2014

Impact performance of high-performance concrete (HPC) and SFRC at 28-day and 56-day under the action of repeated dynamic loading was studied. Silica fume replacement at 10% and 15% by mass and crimped steel fiber ($V_f$ = 0.5%- 1.5%) with aspect ratios of 80 and 53 were used in the concrete mixes. Results indicated that addition of fibers in HPC can effectively restrain the initiation and propagation of cracks under stress, and enhance the impact strengths and toughness of HPC. Variation of fiber aspect ratio has minor effect on improvement in impact strength. Based on the experimental data, failure resistance prediction models were developed with correlation coefficient (R) = 0.96 and the estimated absolute variation is 1.82% and on validation, the integral absolute error (IAE) determined is 10.49%. On analyzing the data collected, linear relationship for the prediction of failure resistance with R= 0.99 was obtained. IAE value of 10.26% for the model indicates better the reliability of model. Multiple linear regression model was developed to predict the ultimate failure resistance with multiple R= 0.96 and absolute variation obtained is 4.9%.

• 대한조선학회논문집
• /
• 제47권3호
• /
• pp.350-358
• /
• 2010

The present paper deals with the comparative study of resistance performance with refrigerated ice and synthetic ice according to the variation of hull form characteristics. The resistance test has been conducted in pack ice condition in each concentration condition. Stem angle has been chosen as main parameters for the variation of hull form characteristics. The correlation of performance between with the refrigerated ice and with the synthetic ice has been shown according to the variation for stem angles. The present study show the possibility of ice test in general towing tank with synthetic ice for the time-consuming research such as hull form optimization although that is confined in pack ice condition. The more parametric study for the properties of synthetic ice is expected to be conducted to have more close correspondence for the test results of refrigerated ice in near future.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
• /
• pp.1549-1552
• /
• 2003

Semiconductor gas sensor using tin oxide as sensing material has been used to detect gases based on the fact that impedance of the sensing material varies when the gas sensor is exposed to the gases. This variation comprises of two parts. The first one is variation in resistance of the sensing material and the other is expressed in terms of the sensor capacitance variation. Normally, only variation of the sensor resistance is considered. In this paper, using AC measurement with a capacitor-coupled inverting amplifier circuit, both changes in the sensor resistance and variations in the sensor capacitance were investigated. These characteristics were represented as magnitude gain and phase shift of AC signal at a specific frequency after passing it through the sensor and the designed circuit. A two-stage artificial neural network, which utilized the information above, was employed to identify and quantify three combustible gases: methane, propane and butane. The network outputs were approximately proportional to concentrations of test gases with reasonable level of error.