• Food Science of Animal Resources
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• v.21 no.2
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• pp.97-102
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• 2001

The characteristic fitness of food to each Sa-sang constitution and the relationship between Han-Yeoul characteristics and chemical composition after classifying Samgye-tang ingredients and other food into Ohn-Yeoul-Ryang-Han characteristic were assessed. When the suitable constitution to the each characteristic was investigated after classifying Samgye-tang ingredients and other food into Han, Ryang, Pyound, Ohn and Yeoul of which fitness case for Soeumin was 44∼63% but fitness case for Soyangin and Taeyangin was only 0∼18%. When the relationship between Samgye-tang ingredients and other food classified into Ohn-Yeoul-Ryang-Han and chemical composition of fatty acid, amino acid, vitamin and mineral was investigated, the value of correlation coefficient was extremely low. There was not the relationship between chemical composition and Han-Yeoul classification. Therefore it should be further investigated the relationship between characteristic and chemical composition by additional analysis index.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.127-135
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• 2012

The processes of chemical and physical weathering occur simultaneously. The objective of this study was to estimate the degree weathered using fractal dimension through comparison with chemical characteristic of soil samples from Pohang (PH) and Kimpo (KP). Comparing chemical characteristics with fractal dimension, $SiO_2$, $Na_2O$, $K_2O$ content decreased and loss of ignition increased as fractal dimension increased. And fractal dimension showed high correlation with CWI while ATI, STI CIW, PI, CIA and RR demonstrated different degrees of correlation with fractal dimension. The tendency of the changes in oxide content and chemical weathering index with increasing fractal dimension appeared to be similar with the chemical changes due to weathering. Therefore, fractal dimension could be a good indicator representing the extent of weathering and chemical changes.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.235-240
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• 2002

The blocks using flyash were prepared in this study. The characteristic of sound absorption of flyash block was investigated. It was revealed that the chemical additives and flyash played an important role to determine the characteristic of sound absorption. Chemical additive affects the capability of sound absorption while flyash affects the characteristic of sound absorption, i.e. high value of the sound absorption coefficient at the specific frequencies(1KHz and 2KHz). The flyash block showed higher sound absorption coefficient than that of the commercial concrete block having carpet on the surface. It was also shown that the sound absorption coefficient increases with increase of the content of flyash in the block. However, it was found that the 70wt% of flyash in the flyash block was the optimum content to obtain the highest sound absorption coefficient.

• Journal of the Korean Society of Combustion
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• v.7 no.1
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• pp.23-30
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• 2002

Instability of oblique detonation waves (ODW) at off-attaching condition was investigated through a series of numerical simulations. Two-dimensional wedge of finite length was considered in $H_2/O_2/N_2$ mixtures at superdetonative condition. Numerical simulation was carried out with a compressible fluid dynamics code and a detailed hydrogen-oxygen combustion mechanism. Present result reveals that there is a chemical kinetic limit of the ODW detachment, in addition to the theoretical limit predicted by Rankine-Hugoniot theory with equilibrium chemistry. Result also presents that ODW still attaches at a wedge as an oblique shock-induced flame showing periodically unstable motion, if the Rankine-Hugoniot limit of detachment is satisfied but the chemical kinetic limit is not. Mechanism of the periodic instability is considered as interactions of shock and reaction waves coupled with chemical kinetic effects. From the investigation of characteristic chemical time, condition of the periodic instability is identified as follows; at the detaching condition of the Rankine-Hugoniot theory, (1) flow residence time is smaller than the chemical characteristic time, behind the detached shock wave with heat addition, (2) flow residence time should be greater than the chemical characteristic time, behind an oblique shock wave without heat addition.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.368-372
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• 2009

A technique to measure the adsorption characteristic of surface area and pore size distribution is proposed and its performance is examined. While the existing equipment utilizes liquid nitrogen, the proposed uses carbon dioxide at the room temperature leading to the small measuring device with easy operation and short measurement time. The performance of the device has been examined with micro-particle carbon cryogel and bamboo activated carbon. The results from the proposed device compared with those of the adsorption apparatus indicate that the measurement of meso-porous material is comparable but micro-porous material gives some error.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.57-64
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• 2011

The purpose of this research is to investigate the anatomical and chemical properties of arrowroots for the use of paper fibers. The cells consisting of arrowroots showed certain affinities with those in the fibers and vessels of hardwood. Its parenchyma cells showed different shapes with those of hardwood. It was observed that starch was filled in the multi-shape cells. The average width and length of arrowroot fibers were $15.2{\mu}m$ ($11.1-20.3{\mu}m$) and 1.9 mm (1.49 mm-2.31 mm), respectively. In the chemical characteristics of arrowroots, the contents of cold- and hot-water, alcohol-benzene, and alkali extractives were 12-17%, 15.6%, and 38.8%, respectively. Its chemical composition was 61.3% holocellulose, 15.5% lignin and 2.0% ash.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.68.3-68.3
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• 2019

Even though the initial mass function (IMF) of the first generation of stars played important roles in reionization of the universe, subsequent star formation, and chemical enrichment of the universe, it is still very uncertain. In this study, among the several indirect ways of estimating the IMF of the population III (Pop III) stars, we make use of extremely metal-poor (EMP; [Fe/H] < -3.0) stars in the Milky Way, in order to infer the characteristic mass range of Pop III stars. As the progenitors of many of the EMP stars are known to be Pop III stars, we attempt to construct the characteristic mass range of the progenitors (e.g., Pop III stars) of the EMP stares by comparing their observed abundance pattern of various chemical elements with chemical yields from supernova models.

• Journal of Power Electronics
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• v.11 no.1
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• pp.82-89
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• 2011

Differences in the frequency characteristic applied to a ripple current may shorten fuel cell life span and worsen the fuel efficiency. Therefore, this paper presents an experimental analysis of the ripple current applied variable frequency characteristic in a polymer electrolyte membrane fuel cell (PEMFC). This paper provides the first attempt to examine the impact of ripple current through immediate measurements on a single cell test. After cycling for hours at three frequencies, each polarization and impedance curve is obtained and compared with those of a fuel cell. Through experimental results, it can be absolutely concluded that low frequency ripple current leads to long-term degradation of a fuel cell. Three different PEMFC failures such as membrane dehydration, flooding and carbon monoxide (CO) poisoning that lead to an increase in the impedance magnitude at low frequencies are simply introduced.

• Journal of the Korean Chemical Society
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• v.13 no.4
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• pp.325-332
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• 1969

An attempt has been made to investigate the nature of the characteristic darkening reaction occurring in the rice bran oil during the storage. Several pigments were separated by using column and thin layer chromatography of the pigments was made in the light of the knowledge of absorption spectral behavior. The presence of trace amount of iron and phytosteryl esters of ferulic acid (3-methoxy-4-hydroxy-cinnamic acid) was found to be responsible for the development of the characteristic color in rice bran oil. The model reactions with the ferulate, iron and fatty acids could be suggested the mechanism.

• Bulletin of the Korean Chemical Society
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• v.21 no.5
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• pp.471-476
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• 2000

Liquid chromatography/mass spectrometry with an atmospheric pressure chemical ionization interface (LC/APCI/MS) is evaluated for the simultaneous determination of carbamate pesticides and organophosphorus pesticides in a single chromatographic analysis. APCI mass spectra of those compounds were obtrained to study their ionization characteristics. APCI provided abundant ions such as protonated molecules and characteristic fragment ions for carbamate pesticides and organophosphorus pesticides. To evaluate the feasibility of the LC/APCI/MS for a routine quantitative analysis, the linearity and repeatability of LC/APCI/MS were examined by measuring standard solution mixtures of five carbamate pesticides and four organophosphorus pesticides over the range of 1 to 100 ㎍/mL. Teh peak areas in chromatograms of characteristic ions for those compounds showed less than 3% of variation from run to run. The standard calibration curves for the nine pesticides show good linearity in the concentration range. The detection limits of the LC/APCI/MS system for those compounds range from 0.006 to 0.2 ng.