• Journal of Life Science
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• v.32 no.5
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• pp.362-367
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• 2022

Hempseed, a dehulled Cannabis fructus, has high nutraceutical potential. It has plenty of essential amino acids, vitamins, and essential polyunsaturated fatty acids, including α- and γ-linolenic acid. Increased exercise capacity, cognitive function, and ameliorative effects against hypercholesterolemia, neuro-inflammation, thrombus formation, and learning and memory impairment were reported in hemp-seed oil-administered models. Therefore, the market prices of hempseed oil are 45~140-fold higher than the other plant-derived oils, such as soy, corn, olive, canola, or linseed oil. In this study, instead of FTIR (Fourier Transform Infrared Spectroscopy) or FTIR-Raman spectroscopy, a simple UV-Vis spectrophotometry method was developed to authenticate the hempseed oil. Measurements of absorbance at 245, 305, and 415 nm of oils and calculations of 245/415 and 315/415 nm provided that the ratios of 245/415 and 315/415 nm of authentic hempseed oils were 12.9 and 9.6, respectively. The 245/415 and 315/415 nm of soy oil, corn oil, canola oil, and linseed oil were 35.4~61.8 and 29.7~50.8, respectively. This simple UV-Vis spectrophotometry method could also be applied to differentiate hempseed oil from blended oil products in markets.

• Analytical Science and Technology
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• v.21 no.4
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• pp.326-331
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• 2008

Distribution coefficients (Kd) of uranyl ion onto divinylbenzene amidoxime resins were measured in sodium carbonate solution and the Kd values were increased up to about 70 as the resin bead size was decreased. At a condition of 0.0044 M $Na_2CO_3$, the adsorption capacity for uranium was $3.4{\mu}mole$ U/g-resin. The Kd values in the 0.5 M $Na_2CO_3-NaHCO_3$ solution, ranging from pH 9 to pH 11, revealed that they were increased as the pH increased and revealed lower values than those in the pure sodium carbonate solution. The amidoxime resins were characterized by FTIR-ATR showing the absorption bands of the amidoxime functional groups. A species of the uranyltricarbonate complex, $UO_2(CO_3)_3^{-4}$, was confirmed by UV-Vis spectroscopy, revealing four absorption peaks between 400 and 500 nm. Uranium was separated from some fission products by a column operation. However, most of the uranium and fission products were eluted before an adsorption and only a small amount of uranium was adsorbed onto the resin due to the low capacity of the resin.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.10
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• pp.2028-2042
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• 1994

Properly defining signal and noise in a self-organizing system like ART(Adaptive Resonance Theory) neural network model raises a number of subtle issues. Pattern context must enter the definition so that input features, treated as irrelevant noise when they are embedded in a given input pattern, may be treated as informative signals when they are embedded in a different input pattern. The ATR automatically self-scales their computational units to embody context and learning dependent definitions of a signal and noise and there is no problem in categorizing input pattern that have features similar in nature. However, when we have imput patterns that have features that are different in size and nature, the use of only one vigilance parameter is not enough to differentiate a signal from noise for a good categorization. For example, if the value fo vigilance parameter is large, then noise may be processed as an informative signal and unnecessary categories are generated: and if the value of vigilance parameter is small, an informative signal may be ignored and treated as noise. Hence it is no easy to achieve a good pattern categorization. To overcome such problems, a Coupled-ART neural network capable of modularized categorization of patterns is proposed. The Coupled-ART has two layer of tightly coupled modules. the upper and the lower. The lower layer processes the global features of a pattern and the structural features, separately in parallel. The upper layer combines the categorized outputs from the lower layer and categorizes the combined output, Hence, due to the modularized categorization of patterns, the Coupled-ART classifies patterns more efficiently than the ART1 model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.391-397
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• 2011

The use of Hydrogen as a fuel is receiving considerable attention and as a result, research on novel methods of hydrogen production is necessary so that the hydrogen demands in the future can be satisfied. This study presents experimental data on methanol Autothermal Reformation that quantifies the relationship between the oxygen-to-methanol ratio ($O_2/CH_3OH$) and reformer efficiency. For each catalyst configuration, the $O_2/CH_3OH$ was varied from 0.1 to 0.4, with an increment of 0.05, to investigate the effects of $O_2/CH_3OH$ on the reactor performance, including temperature profile, conversion, and efficiency. $O_2/CH_3OH$ was increased from 0.15 to 0.20, and the catalyst bed temperature increased by $235^{\circ}C$ to approximately $550^{\circ}C$. The catalyst bed temperature increased with increasing $O_2/CH_3OH$ as the reaction shifted from endothermic to exothermic reaction and as a result, excess heat, which raised the reactor temperature, was generated. The reactor performance was shown to be highly dependent on $O_2/CH_3OH$. The optimum $O_2/CH_3OH$ = 0.30 found in the experimental tests is 30% higher than the theoretical optimum of 0.23. This is attributed to a combination of factors such as the concentrations of the $O_2$ and $CH_3OH$ gas, reaction rate, catalyst effects, heat loss from the reactor, and the difference between the actual amounts of reaction products formed and the theoretical amounts of the reaction products.

• Restorative Dentistry and Endodontics
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• v.31 no.6
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• pp.477-484
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• 2006

The purposes of this study were to compare the apical terminus width of simulated curved root canal prepared with three NiTi file systems used by undergraduates for evaluation the effects of flute angle and pitch or radial land on reducing screw-in effect and to determine more safe NiTi file system for inexperienced operators. Fifty inexperienced undergraduate students prepared 150 simulated curved root canals in resin blocks with three NiTi file systems ; ProFile$^{(R)}$, Hero Shaper$^{(R)}$, K3$^{TM}$. The electric motor set at a speed of 300 rpm and torque of 30 in a 16 : 1 reduction handpiece was used. The simulated root canal was prepared to ISO #25 sizes with each file system. The scanned images of pre- and post-instrumented canal of resin block were superimposed. To evaluate the screw-in effect of three NiTi file systems, apical terminus width of root canal was measured from superimposed images and statistical analysis was performed. There were significant differences in three NiTi flle systems. ProFile$^{(R)}$ had significantly smaller width than Hero Shaper$^{(R)}$ and K3$^{TM}$"" (P < 0.05), but no significant difference was observed between K3$^{TM}$ and Hero Shaper$^{(R)}$. Under the condition of this study, active file system (Hero SHaper$^{(R)}$, K3$^{TM}$) with variable pitch and helical angle had more screw-in effect than passive file system (ProFile$^{(R)}$) with constant pitch and helical angle. It seems that the radial lands play more important role in reducing screw-in effect.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.395-405
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• 2009

The maturity of amber matrix and inclusion was studied to explore the effect of heat treatment on the formation of the sun spangle in the transparent Baltic amber from Gdansk, Poland. Optical microscope revealed two types of inclusions in the original amber samples. The inclusions in the amber which had sun spangle were dramatically expanded by the heat treatment, comparing to those without sun spangle which contains fissure and shows different refractive index. The amber sample which didn't show sun spangle after the heat treatment showed a strong carbon related peak in TOF-SIMS spectra and weak oxygen related peak. it means that the maturity of this amber sample is comparatively higher than the one with spangle. The two amber samples show similar IR spectra before the heat treatment. However, the amber which had sun spangle exhibited an additional 1019 $cm^{-1}$ absorption peak and a more intense 887 $cm^{-1}$ peak. The different chemical compositions between the two types of amber is believed to be due to the different absorption spectra between 1000~600 $cm^{-1}$. According to the study of DSC analysis, the two samples show different DSC profiles. Although they have the same geological origin, their geological ages are different and have different chemical compositions. Thus, they exhibited different behavior after the heat treatment. The formation of sun spangle seemed to depend on the difference in the heat expansion rate of amber matrix with different maturity and chemical compositions.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.166-177
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• 2022

The Shiveet Khairkhan is located on Tsengel Som in the middle of Bayan-ulgi Aimag in the Altai region. Various remains have been identified, and it has been found to be an important area of the Eurasian steppe. In this study, the characteristics of textile fibers and dyes excavated from the tombs of the 1st~3rd century Xianbei period in the sites of Shiveet Khairkhan, Mongolia were investigated. As a result of analysis using optical microscopic observation and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) for fiber identification, green and yellow fabrics were identified as silk fabrics. To investigate the properties of the dye, the surface reflectance of the dyed fabric was measured using an fiber optic reflectance spectrophotometer for non-destructive analysis. The green fabric appeared similar to the reflection spectrum of indigo dye. In addition, as a result of component analysis using gas chromatography-mass spectrometry, isatin and indigotine were detected. Isatin and indigotine are characteristic components of indigo dye, and it was found that the green fabric of the tombs of the Xianbei period was dyed using indigo dye. It was difficult to identify the type of dye in the yellow fabric as a result of reflectance spectrum and gas chromatography analysis. Indigo plants are a dye used for blue dyeing from thousands of years ago, and many species are distributed around the world. It was confirmed that the fabric was relatively well preserved and indigo dye was used for the green Jikryeongui (garment with a straight collar) in the ancient tomb of the Xianbei period about 1,800 years ago, even though it was buried for a long time. Scientific investigation of textile cultural heritage is an essential process for conservation treatment, restoration, exhibition, and the creation of a conservation environment. It is expected that related research will be activated in the future and will be helpful in interpreting the living culture at the time, preserving textiles, and a conservation environment.

• Korean Journal of Heritage: History & Science
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• v.56 no.3
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• pp.158-171
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• 2023

Pottery filled with organic materials was excavated from the G-2 building site of Yongjangseong Fortress, Jingo, a relic of the Goryeo Dynasty. In this study, the characteristics of organic material were confirmed by a scientific analysis of organic material in pottery found at the palace in Yongjangseong, Jindo. In addition, it was intended to review the analysis method to identify the natural resin and to secure characteristic components(biomarkers) for each natural resin and use them as basic data in the future. The organic materials in the pottery were analyzed using attenuated total reflectance Fourier-transformed infrared spectroscopy(ATR-FTIR) and gas chromatography mass spectrometry(GC-MS). The infrared spectral characteristics were estimated to be natural resin, and biomarkers of organic materials were identified as sesquiterpene-based compounds(C₁₅H₂₄, MW 204) and derivatives. The lacquer(T.vemicifluum) is composed mainly of alkenes, alkanes, and catechol. Pine resin(P.densiflora), on the other hand, is primarily composed of diterpenoid(abietic acid, pimaric acid) and Whangchil(yellow lacquer) is identified to have sesquiterpenes(such as selinene, muurolene, calamenene) as its main components. So, the organic material in the pottery can be identified as Whangchil by comparing their compounds with modern resin materials from Dendropanax. morbifera that correspond with the results. Whangchil, which is exuded from the Dendropanax. morbifera, has been used as a natural coating materials since ancient times, and it has been confirmed that the characteristic components are well preserved even 700 years later. It can be assumed that the interior Whangchil was stored not for use as a coating, but rather for ritual purposes when the building was constructed, because the pottery was found near the cornerstone. Furthermore, based on simplified sample preparation using pyrolysis-gas chromatography mass spectrometry(Py-GC-MS), the thermal decomposition products were found to be similar to the characteristic components, suggesting that this method can be applied to the identification of natural resins used in historic artifacts.