• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.615-620
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• 2015

Polypropylene (PP)/bamboo fiber (BF) composites were fabricated by twin screw extruder in order to investigate effects of the compatibilizer on physical properties of PP/BF composites. The content of BF changed from 10 to 25 wt% and that of the compatibilizer was fixed at 3 wt%. Maleic anhydride grafted PP (PP-g-MAH) was used to increase the compatibility between PP and BF as a compatibilizer. Chemical structures of the composites were confirmed by the existence of carbonyl group (C=O) stretching peak at $1,700cm^{-1}$ in FT-IR spectrum. Considering the degradation and mechanical properties, the optimum extrusion conditions were selected to be $210^{\circ}C$ and 100 rpm, respectively. There was no distinct changes in melting temperature of the composites, but the crystallization temperature increased by $10-20^{\circ}C$ owing to the heterogeneous nuclei of BF. It was checked that the optimum BF content was in the range of 15-20 wt% from the results of tensile and flexural properties of the composites. The effect of the compatibilizer on mechanical properties was confirmed by SEM images of fractured surface and contact angles.

• Journal of Biosystems Engineering
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• v.36 no.2
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• pp.130-139
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• 2011

Three modes of VIS/NIR spectroscopic measurement (interactance and two modes of transmission) were compared for their ability to estimate soluble solids content (SSC) of 'Shingo' pear non-destructively. The two transmission modes are named as full- and semi-transmission, where full-transmission stands for passing of light through abdomen of pear and semi-transmission is for transit of light mainly through flesh of pear. For comparison of the modes, prediction models developed from the collected spectroscopic data by the three modes were developed and tested for comparison of their performance. Partial least square regression (PSLR) was used to develop the models and various pre-processing methods were applied to develop models of high accuracy. The experiment was repeated three times with pears produced in different regions. The experiments resulted that selection of pre-processing is very important to attain accurate models, and multiplicative scatter correction (MSC) was selected as a pre-processor of high accuracy for the three modes of spectroscopic measurement in every experiment. Except for MSC, different group of pre-processing methods were selected for the three modes of measurement in every experiment without any tendency to the tested modes of measurement and pears of different produced region. Root-mean-square error of prediction (RMSEP) of prediction models of the three modes of measurement using prepreocessor of MSC were compared for their ability to estimate SSC. The models resulted in ranges of $0.37{\sim}0.57^{\circ}Brix$, $0.65{\sim}0.72^{\circ}Brix$, $0.39{\sim}0.51^{\circ}Brix$ for interactance, full- and semi-transmission, respectively. As shown, modes of semi-transmission and interactance resulted about the same level of prediction accuracy and were noted as modes of high performance to predict SSC.

• The Korean Journal of Food And Nutrition
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• v.17 no.2
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• pp.156-162
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• 2004

This study was performed as a part of comparative biological studies of carotenoid pigment for the unutilized biological products. The content of total carotenoid in the integument of wild catfish were 0.27(${\pm}$0.7) mg％ and composed of 25.8％ zeaxanthin, 9.7％ diatoxanthin and 9.1 ％ cynthiaxanthin as major carotenoid. The content of total carotenoid in the integument of cultured catfish were 0.07(${\pm}$0.03) mg％ which is relatively lower compare to wild catfish and composed of 48.5％ lutein, 13.9％ zeaxanthin and 13.3％ isocryptoxanthin as major carotenoid. The total carotenoid contents of the slender catfish were 0.75(${\pm}$0.25) mg％ which is relatively higher compare to other species of catfishes. The carotenoids were composed of 24.5％ zeaxanthin, 24.1 ％ 7'8'-dihydro-${\beta}$-carotene-4-ol, 17.9％ 7'8'-dihydro-${\beta}$-carotene and 10.8％ 7'8'-dihydro-${\beta}$-carotene-3-01 as major carotenoid and 8.7％ diatoxanthin, 6.7％ cynthiaxanthin and 5.0％ lutein as minor carotenoid. Based on these data, as a comparative studies of carotenoid in integument of siluridae, parasiloxanthin and 7',8'-dihydroparasiloxanthin which are the characteristic carotenoid of catfish from biwa lake in Japan, Slender catfish contained more based on 7',8'-dihydro-${\beta}$-carotene while that of wild and cultured catfishes were not found, indicating that carotenoid pigment of slender catfish depend on their living conditions.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.1-5
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• 2018

In this study, the effects of indium (In) doping in InGaN/GaN multi quantum well (MQW) on photoelectrochemical (PEC) properties were investigated. Each quantum well (QW) layer with controlled In content were grown on sapphire substrate. Before growth of MQW, GaN growth consisted of various stages in the following order: buffer GaN growth, undoped GaN growth, and Si-doped n-type GaN growth. Absorbance of InGaN/GaN MQW having different In composition was higher than that of the InGaN/GaN MQW having a constant In composition. It indicates that InGaN layer having different In composition absorbs light having a broad spectrum energy. These results are in agreement with those in photoluminescence (PL). After evaluation of PEC properties, it demonstrated that InGaN/GaN MQW having different In composition was improved InGaN/GaN MQW having constant In composition in PEC water splitting ability.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1138-1150
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• 2020

In this study, an experiment was conducted to develop a sunscreen with antioxidant effects by simultaneously investigating the antioxidant and UV protection capabilities of various plant extracts. First, to investigate the UV-blocking ability of 33 kinds of plant extracts, the absorbance spectrum between the UV wavelength of 280 to 400 nm was investigated. Arrowroot, graviola, wheat sprout, sangbaek skin, thorn meal, lacquer, etc. 11 species were selected. The total polyphenol content, total flavonoid content, and DPPH radical scavenging activity of the selected plant extracts are measured to examine the degree of antioxidant activity, and from this, it is a plant extract that has excellent UV protection and antioxidant activity at the same time. The species was selected. A gel-shaped cream is prepared by mixing the selected gold, hops, and licorice extracts in a ratio of 1:1:1, and the UV protection effect of this cream is measured when the cultured cells are irradiated with UV rays. Determined by the method. As a result of the study, it was confirmed that the selected mixture of plant extracts complemented each other in terms of ultraviolet absorption ability and increased cell damage protection effect. Through these results, it was confirmed that it was possible to develop a sunscreen with an antioxidant effect if the antioxidant and sunscreen capabilities of various plant extracts were determined at the same time.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.231-234
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• 1973

Dried lavers, Porphyra yezoensis Ueda, were stored at $20^{\circ}C$ for 10, 25 and 45 days under a dry and humid conditions respectively, and changes in the contents of organic acids were studied by GLC and supplementary use of GC-MS. 1) Out of eight acids determined, i. e., pyruvic, lactic, oxalic, malonic, fumaric, succinic, malic, and citric acid, relatively abundant ones were oxalic, succinic, malic, and citric acid. 2) Oxalic, malic, and succinic acid did not show any notable changes in their contents under a dry condition, however, under a humid condition the contents of the former tow acids decreased rapidly showing contrast to that of succinic acid, of which content increased markedly. The content of citric acid rapidly· decreased independent of the storage conditions. 3) Among some unidentified components, two of them were presumed to be aromatic acids from their mass spectra. The contents of the two acids decreased slowly under a dry condition, however, rapidly decreased under a humid condition and after 45 days storage almost all of them disappeared. 4) The contents of total volatile acids were increased under the both storage conditions, however, the rate of increment was larger under a humid than under a dry condition.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.331-341
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• 2016

To evaluate the physicochemical and radiological properties of raw materials and by-products in domestic distribution, about 220 samples with 16 species were prepared. We measured the energy spectrum and the chemical content, such as U, Th, and K, using a $LaBr_3$ scintillation detector and ED-XRF. In addition, HPGe detector was used to analyze the radioac-tivity of $^{234}Th$, $^{234}mPa$, and $^{214}Bi$ in uranium decay series and $^{228}Ac$, $^{212}Pb$, and $^{208}Tl$ in thorium decay series, and $^{40}K$. The correlation between characteristic variables, such as the count rate in several ROIs, chemical content, and radioactivity, was assessed to infer the radioactivity of natural radionuclides through a rapid screening method. Based on the results, a characteristic database for raw material and by-product in domestic distribution was established and it will provide useful information in the analysis procedure and improve the accuracy and reproducibility in the analysis of natural radionuclides.

• Journal of the Mineralogical Society of Korea
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• v.24 no.3
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• pp.151-164
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• 2011

Mineralogical and petrological characteristics were investigated on matrix of dense gray, vesiculate gray, brown and black pumice in Ulleung Island by using XRD, FT-IR, XRF, SEM and thermal analysis. According to the analysis, most of pumice matrix are amorphous and include very small amount of sanidine and anorthoclase. Since the adsorption moistures, which commonly observed as O-H peak in FT-IR spectrum, are not identified in thermal analysis, it seems reasonable to conclude that content of the adsorption moisture has very low level. Although pumice has a large specific surface area, with long time elapsed after eruption, pumice matrix shows very low degree of hydration alteration due to the low level of water content. In SEM images, most surfaces of pumice show morphological characteristics such as various shapes of vesicle with wrinkled and thin walls resulted from ductile coalescence. Dense gray pumice formed in the initial stage includes small vesicles less than $15{\mu}m$ in size with subangular to angular shapes, free of ovoid vesicle. These characteristics are interpreted to have related to the hydrous environment derived from phreato-plinian eruption. Submicron particles observed as amorphous alumina silicate assemblages in vesicle surface are considered as particles sticked to the matrix surface through rapidly cooling process during ascent of alkali phonolitic magma. It indicates that these particles coexisted partly with crystallized alkali feldspar.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.167-173
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• 2000

Four glasses of $B_2O_3-Bi_2O_3-PbO-SiO_2$ (BBPS) system were prepared by melting the appropriate amounts of reagent grade oxides of $B_2O_3$, $Bi_2O_3$, PbO, and $SiO_2$ in an open crucible. The differential thermal analysis showed crystallization temperature decreased with increasing $Bi_2O_3$ or PbO content in the sample. The structures of glasses system were studied using scanning electron microscopy and Fourier transform-Infra red (FT-IR) spectroscopy. The UV cut-off and refractive index were found to be sensitive to the $Pb^{+2}$ and $Bi^{+3}$ content in the glasses. The behavior of the IR spectra of the glasses in the BP series was consistent with a role of $Bi_2O_3$ as a network former. In the BP series of glasses, the result of IR spectrum indicated that PbO behaved as a network former.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.631-639
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• 2011

This research was conducted to investigate potential use of New Zealand spinach (Tetragonia tetragonoides) as a new vegetable crop which will be cultivating in salt-affected soils including reclaimed land. Traditionally New Zealand spinach has been studied to explore functional compound or salt removing potential. To cultivate the crop species in the salt-affected soil widely, it is essential to obtain salt and soil texture responses under the controlled environment. Fifty nine New Zealand spinach ecotypes native to Korean peninsula first collected over seashore areas, and primitive habitat soil environment was evaluated by analyzing soil chemical properties from 32 locations. Different textures of sandy, silt loam, and sandy loam soils were prepared from nearby sources of sea shore, upland and paddy soils, respectively. Target salinity levels of 16.0 dS/m, 27.5 dS/m, 39.9 dS/m, and 52.4 dS/m in electrical conductivity (ECw) were achieved by diluting of 25, 50, 75, 100% (v/v) sea water to tap water (control, 0.6 dS/m), respectively. Various measurements responding to soil texture and irrigation salinity included plant height, root length, fresh weight (FW), dry weight (DW), leaf parameters (leaf number, leaf length, leaf width), lateral branching, and inorganic ion content. was found to adapt to diverse habitats ranging various soil chemical properties including soil pH, organic matter, exchangeable bases, EC, and cation exchange capacity (CEC) in Korea. Responding to soil texture, New Zealand spinach grew better in silt loam and sandy loam soil than in sandy soil. Higher yield (FW and DW) seemed to be associated with branch number (r=0.99 and 0.99, respectively), followed by plant height (r=0.94 and 0.97, respectively) and leaf number (r=0.89 and 0.84, respectively). Plant height, FW, and DW of the New Zealand spinach accessions were decreased with increasing irrigation salinity, while root length was not significantly different compared to control. Based on previous report, more narrow spectrum of salinity range (up to 16 dS/m) needs to be further studied in order to obtain more accurate salinity responses of the plant. As expected, leaf Na content was increased significantly with increasing salinity, while K and Ca contents decreased. Growth responses to soil texture and irrigation salinity implied the potential use of New Zealand spinach as a leafy vegetable in salt-affected soil constructed with silt loam or sandy loam soils.