• Journal of Korean Society of Industrial and Systems Engineering
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• v.5 no.7
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• pp.29-32
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• 1982

On designing the rectifying inspection plans of double sampling, the relations of the sample sizes $n_1$, $n_2$ and the acceptance numbers $c_1$, $c_2$ are obtained by using the Chi-square distribution. As the average number of pieces inspected per lot is a function of $c_1$ and $c_2$, the optimal solution is the values of $c_1^*$ and $c_2^*$ for which the average amount of inspection is a minimum. Then the values of $n_1^*$ and $n_2^*$ are easily obtained from the equations given by ($n_1$, $n_2$) and ($c_1$, $c_2$).

• 전기의세계
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• v.28 no.4
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• pp.39-46
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• 1979

The effective ionization coefficient in $SF_{6}$/$N_{2}$ mixtures was attempted to derive from the pure gases. Measurements of static breakdown voltage were made under the uniform field at pressures up to 4 bar in order to compare with the results obtained from this assumption. The relative performance of $SF_{6}$/$N_{2}$ mixtures to pure $SF_{6}$ was also investigated. The effect of surface roughness on discharge thresholds in $SF_{6}$/$N_{2}$ mixtures was calculated employing the simplified model and mesurements of breakdown voltages for a gap with an artificial protrustion were also made. The experimental results show that the effective ionization coefficient in gas mixtures can not be reliably estimated from the values measured for the pure gases. Therefore, basic parameters for $SF_{6}$/$N_{2}$ mixtures must be measured by investigation of the mixtures themselves. The relative performance of mixtures to pure $SF_{6}$ could be considered with the values of pR.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.35-39
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• 2013

The flash point is an important indicator of the flammability of a chemical. In this study, the flash points for the n-propanol+n-butanol and n-propanol+acetic acid systems were measured by Tag open-cup apparatus. The experimental data were compared with the values calculated by the Raoult's law and optimization method based on van Laar and UNIQUAC equations. The calculated values by optimization method were found to be better than those based on the Raoult's law.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.181-185
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• 2005

The flash point is one of the most important combustible properties used to determine the potential for fire and explosion hazards of industrial material. An accurate knowledge of the flash point is important in developing appropriate preventive and control measures in industrial fire protection. The flash points for the n-butanol+n-propionic acid and n-propanol+n-propionic acid systems were measured by using Tag open-cup apparatus(ASTM D 1310-86). The experimental data were compared with the values calculated by the laws of Raoult and van Laar equation. The calculated values based on the van Laar equation were found to be better than those based on the Raoult's law.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.7
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• pp.464-472
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• 2001

Asymmetric n-MOSFET＇s for improving packing density have been fabricated with 0.35 ${\mu}{\textrm}{m}$ CMOS process. Electrical characteristics of asymmetric n-MOSFET show a lower saturation drain current and a higher linear resistance compared to those of symmetric devices. Substrate current of asymmetric MOSFET is lower than that of symmetric devices. Asymmetric n-MOSFET＇s have been modeled using a parasitic resistance associated with abnormally structured drain or source and a conventional n-MOSFET model. MEDICI simulation has been done for accuracy of this modeling. Simulated values of reverse as we11 as forward saturation drain current show good agreement with measured values for asymmetric device.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.19-25
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• 2017

This paper deals with integer factorization of two prime p,q of SHA-256 secure hash value n for Bit coin mining. This paper proposes an algorithm that greatly reduces the execution time of Pollard's rho integer factorization algorithm. Rho(${\rho}$) algorithm computes $x_i=x^2_{i-1}+1(mod\;n)$ and $y_i=[(y^2_{i-1}+1)^2+1](mod\;n)$ for intial values $(x_0,y_0)=(2,2)$ to find the factor 1 < $gcd({\mid}x_i-y_i{\mid},n)$ < n. It however fails to factorize some particular composite numbers. The algorithm proposed in this paper applies multiple initial values $(x_0,y_0)=(2^k,2^k)$ and ($2^k,2$), $2{\leq}k{\leq}10$ to the existing Pollard's Rho algorithm. As a results, the proposed algorithm achieves both the factorization of all the composite numbers and the reduction of the execution time of Pollard's Rho by 67.94%.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.899-906
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• 2013

Using generated conformations from docking analysis by Gold algorithm, some 3D-QSAR models; CoMFA and CoMSIA have been created on 39 N-benzoylated phenoxazines and phenothiazines, including their S-oxidized analogues. These molecules inhibit the polymerization of tubulin into microtubules and thus they have been studied for the development of antitumor drugs. Training set for the CoMFA and CoMSIA models using 30 docked conformations gives $q^2$ Leave one out (LOO) values of 0.756 and 0.617, and $r^2$ ncv values of 0.988 and 0.956, respectively. The ability of prediction and robustness of the models were evaluated by test set, cross validation (leave-one-out and leave-ten-out), bootstrapping, and progressive scrambling approaches. The all-orientation search (AOS) was used to achieve the best orientation to minimize the effect of initial orientation of the structures. The docking results confirmed CoMFA and CoMSIA contour maps. The docking and 3D-QSAR studies were thoroughly interpreted and discussed and confirmed the experimental $pIC_{50}$ values.

• Fire Science and Engineering
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• v.18 no.3
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• pp.9-17
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• 2004

The values of physical properties of the inert gases of Ar, $N_2$, $CO_2$ were calculated by the empirical equations. The regression coefficients were obtained by the experimental data and the resulting calculated values. For the empirical equation with a lower regression coefficient, a new correlation was suggested. At an atmosphere pressure, the empirical equation was confirmed by the experimental values for the viscosity, density, saturated pressure, and surface tension of Ar, $N_2$, $CO_2$. The correlation coefficients of the empirical equations proposed in this work was higher than 0.99.

• The Journal of Advanced Prosthodontics
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• v.6 no.4
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• pp.317-324
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• 2014

PURPOSE. This study was to evaluate the effect of grinding of the inner metal surface during the porcelain try-in stage on metal-porcelain bonding considering the maximum temperature and the vibration of samples. MATERIALS AND METHODS. Ninety-one square prism-shaped ($1{\times}1{\times}1.5mm$) nickel-chrome cast frameworks 0.3 mm thick were prepared. Porcelain was applied on two opposite outer axial surfaces of the frameworks. The grinding was performed from the opposite axial sides of the inner metal surfaces with a low-speed handpiece with two types of burs (diamond, tungsten-carbide) under three grinding forces (3.5 N, 7 N, 14 N) and at two durations (5 seconds, 10 seconds). The shear bond strength (SBS) test was performed with universal testing machine. Statistical analyzes were performed at 5% significance level. RESULTS. The samples subjected to grinding under 3.5 N showed higher SBS values than those exposed to grinding under 7 N and 14 N (P<.05). SBS values of none of the groups differed from those of the control group (P>.05). The types of bur (P=.965) and the duration (P=.679) did not affect the SBS values. On the other hand, type of bur, force applied, and duration of the grinding affected the maximum temperatures of the samples, whereas the maximum vibration was affected only by the type of bur (P<.05). CONCLUSION. Grinding the inner metal surface did not affect the metal-porcelain bond strength. Although the grinding affected the maximum temperature and the vibration values of the samples, these did not influence the bonding strength.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.186-190
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• 1999

Isotope ratio ($^{15}N/^{14}N$) and nitrate-nitrogen concentration in groundwater were measured to investigate the effect of chemical fertilizer and livestock manure on temporal variations in nitrate-nitrogen concentration and to estimate the contribution of fertilizer and manure to groundwater contamination by nitrate. Four study wells from a rural area in Kyonggi province were selected. One well was located on an upper site from a livestock feedlot, and the others were situated at lower sites from the feedlot. The ${\delta}^{15}N$ values were analyzed by a stable isotope ratio mass spectrometer (Micromass, VG Optima IRMS). Reproducibility of the method and precision of the mass spectrometer were below 1.0 and 0.1‰, respectively Even though study wells were located at the same area, nitrate-nitrogen concentrations and ${\delta}^{15}N$ values differed and fluctuated during the sampling period. The ${\delta}^{15}N$ values of well located at upper site from the feedlot were extremely variable (-1.48~20.80‰). The ranges of ${\delta}^{15}N$ value of three wells situated at lower sites from the feedlot were 11.83~20.73 (ave. 16.11), 8.90~11.73 (ave.11.01), and 5.29~12.73‰ (ave. 8.21‰) with increasing distance from the feedlot. The average values of contribution proportion of nitrogen derived from livestock manure to nitrate-nitrogen in groundwater were 79% for the well closet to the feedlot, 44% for the well most distant from the feedlot, and 56% for the well in between the two wells.