• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.52-58
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• 2018

The flash point is one of the most important properties to characterize fire and explosion hazard of flammable liquid mixture. In this paper, the flash points of ternary liquid mixture, n-nonane+n-decane+n-tridecane system, were measured using Seta flash closed cup tester. The measured values were compared with the calculated values using Raoult's law and multiple regression analysis. The absolute average errors(AAE) of the results calculated by Raoult's law is $0.6^{\circ}C$. The absolute average errors of the results calculated by multiple regression analysis is $0.4^{\circ}C$. As can be seen from AAE, the calculated values based on multiple regresstion analysis were found to be better than those based on Raoult's law.

• Korean Journal of Crystallography
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• v.6 no.1
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• pp.27-35
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• 1995

The crystal structure of 1-tert-butoxycarbonyl-4-[N-(tert-butoxycarbonyl)-N-(ethoxycarbonylmethyl)amino]-3-phenylsulfonylpyrrolidind [C24H36O8N2S] has been from single crystal x-ray diffraction study ; C24H36O8N2S triclinic, p1, a=11.363(8)Å, b=11.589(6)Å, c=11.013(10)Å,α=95.32(6)°,β=98.64(7)°,γ=79.57(5)°,V=1406.8(18)Å3, t=293K, Z=2, CuKα(λ=1.5418Å). The molecular structure was solved by diredt method and refined by full-matrix least squares to a final R=9.78% for 3621 unique observed [F≥4σ(F)] reflections and 703 paramenters.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.219-227
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• 1981

The crystal structure of sulfamethoxypyridazine has been solved by the direct method and refined by least squares methods from three-dimensional data collected by the multiple-film technique to a final residual of 8.5%. Two molecules (A and B) in one asymmetric unit are different each other in the conformation about S-N(2) bond, and are linked together by N(2A)H${\ldots}$N(3B) and N(2B)H${\ldots}$O(1A)S hydrogen bonds. Benzene and pyridazine rings make the angles of $89^{\circ}$ and $77^{\circ}$ for molecules A and B respectively.

• Journal of the Korean Geophysical Society
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• v.6 no.3
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• pp.155-164
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• 2003

The validity and efficiency of the roll-along technique widely used in 2-D electrical resistivity survey are analyzed in case of the dipole-dipole and the Wenner-Schlumberger arrays by numerical modelling. The shallow anomalous resistivity bodies are successfully inverted both in the dipole-dipole and in the Wenner-Schlumberger arrays because the shallow data of pseudosection are not omitted by the roll-along technique. However, the deep anomalous resistivity bodies can not be well resolved due to the skip of observed data which is more significant in the Wenner-Schlumberger array having relatively poor horizontal coverage of obtaining data. Carrying out electrical survey adopting the dipole-dipole array, the skip of data is insignificant because it is unfeasible to expand the electrodes to the maximum electrode separation coefficient($n_max$) owing to low S/N ratio. In case of the Wenner-Schlumberger array, however, because it is generally feasible to expand the electrodes $n_max$ to the owing to high S/N ratio, it is highly possible that skip of data from the roll-along technique causes significant distortion of inversion results. Therefore, adopting the Wenner-Schlumberger array having deeper median depth(Edwards, 1977) than do the dipole-dipole array on condition of the same unit electrode spacing( ($a$) ) and $n_max$, it is recommended to determine $a$ based on not $n_max$but $n_prob$free from the skip of observing data and forward electrodes with keeping overlap interval 3/4 of the survey line length in order to reduce the distortion of resistivity structure and perform resistivity survey efficiently. These results are confirmed by numerical modelling.

• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.247-251
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• 1985

Dichloro cobalt(III) complex of a flexible tetradentate ligand of ethylenediamine-N,N'-di-S-${\alpha}$-propionic acid (eddp) has been prepared via the air-oxidation technique. Only ${\Delta}$-cis isomer has been yielded showing high stereoselectivity of the eddp ligand. Elemental analysis, ir, nmr and electronic absorption spectra have been used to characterize the complex and the absolute configuration of the complex is assigned by means of the nmr spectroscopy.

• Water for future
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• v.15 no.2
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• pp.33-39
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• 1982

For the determination of a reservoir capacity Rippl's mass-curve method has long been used with the past river flow data assuming the same flow records will be repeated in the future. In this study the synthetic generation methods of thomas-Fiering type and harmonic analysis were used to synthetically generate 50 years of monthly river inflows to three single-purpose reservoris(Chuncheon, Chungpyong, Hwacheon) and three multi-purpose reservoirs(Soyany, Andon, Daichung). The generated sequences of monthly flows were analyzed based on the range concept, and hence the so-determined ranges for single-prupose and multi-purpose rewervoirs were correlated with the number of monthly flow subseries, resulting an empirical equation of the Feller's type. (1) Single-purpose reservoir $$R_n=2.8357 I\sqrt{n}$$ (2) Multi-purpose reservoir $$R_n=2.5145 I\sqrt{n}$$ where, $R_n$:Range(㎥/S-M) n:periodic(12 months, ……120 months) I:Input mean(㎥/S-M) In Korea, the monthly inflow data generation will be fit to the Thomas-Fiering type, and this paper shows that the periodic range is easily calculated without the Rippl's mass-curve method as shown above formula.

• Journal of the Korea Society of Computer and Information
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• v.16 no.8
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• pp.103-108
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• 2011

Generally, Miller-Rabin method has been the most popular primality test. This method arbitrary selects m at k-times from m=[2, n-1] range and (m,n)=1. Miller-Rabin method performs $k{\times}r$ times and reports prime as $m^d\;{\equiv}\;1(mod\;n)$ or $m^{2^rd}\;{\equiv}\;-1(mod n)$ such that n-1=$2^sd$, $0\;{\leq}\;r\;{\leq}\;s-1$. This paper suggests more simple primality test than Miller-Rabin method. This test method computes c=$p^{\frac{n-1}{2}}(mod\;n)$ for k times and reports prime as c=-1. The proposed primality test method reduces $k{\times}r$ times of Miller-Rabin method to k times.

• 대한예방의학회:학술대회논문집
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• 1993.10a
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• pp.95-96
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• 1993

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.313-315
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• 2019

A new synthetic method for N-hydroxysuccinimide (NHS), which is widely used in fine chemical and cosmetic industries, was developed. In a conventional synthesis, NHS is obtained by reacting $NH_2OH$ with succinic anhydride in a yield of about 70% using strong acid as a catalyst, which has an advantage of obtaining NHS relatively easily. However, it is expensive because of using a high cost succinic anhydride. In order to overcome this issue, we developed a new synthetic method for NHS with a moderate yield of 80% using a low cost succinic acid instead of succinic anhydride, alongside a stable Lewis acid catalyst, Zn acetate. As a result of the economic evaluation, it was confirmed that the cost reduction effect was about 15%.

• Journal of Energy Engineering
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• v.16 no.1 s.49
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• pp.46-52
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• 2007

The piecewise constant angular approximation is developed to replace the conventional angular quadrature sets in the solution of the second-order, multi-dimensional $S_{N}$ neutron transport equations. The newly generated quadrature sets by this method substantially mitigate ray effects and can be used in the same manner as the conventional quadrature sets are used. The discrete-ordinates and the piecewise-constant approximations are applied to both the first-order Boltzmann and the second-order form of neutron transport equations in treating angular variables. The result is that the mitigation of ray effects is only achieved by the piecewise-constant method, in which new angular quadratures are generated by integrating angle variables over the specified region. In other sense, the newly generated angular quadratures turn out to decrease the contribution of mixed-derivative terms in the even-parity equation that is one of the second-order neutron transport equation. This result can be interpreted as the entire elimination or substantial mitigation of ray effect are possible in the simplified even-parity equation which has no mixed-derivative terms.