• Korean Journal of Soil Science and Fertilizer
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• v.51 no.2
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• pp.101-110
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• 2018

There is an increasing concern over arsenic (As) contamination in rice since Codex Committee on Contaminants in Food (CCCF) discuss on maximum levels for As in rice in 2010. This study was conducted to reduce As concentration in rice by soil amendment treatments in paddy field soils contaminated by As. The selected four amendments were poultry manure, agri-lime, steel slag, and gypsum with the addition of 3% or 5% (w/w) on a dry basis. The As reduction effect could not be verified, as a result of the pot test by adding poultry manure to the paddy soil around the mine located in Yesan. Among the agri-lime treated rice cultivated pots, the As concentration increased up to 32.1%. On the other hand, the content of As in the sample pots treated with steel slag and gypsum decreased by 65.4% and 63.4%, respectively. On the basis of the results of these pot experiments, the field test was carried out in the As polluted rice field around the mine located in Yesan, and when the four amendments were treated, the As content in the brown rice reduced in all the amendment treatments compared with the control plot. The As reduction in brown rice of the amendment was confirmed to be higher efficiency by the order of gypsum > steel slag > poultry manure > agri-lime. As a result of pot experiments using paddy soil around the mine located in Seosan, As stabilization efficiency in rice and As reduction effect could not be determined by comparison to the control. From the rice cultivated from agri-lime treated pot, As concentration increased by 15.8% in rice. On the other hand, the As content of the pots treated with steel slag and gypsum decreased by 39.1% and 60.2%, respectively. In conclusion, distinguished As reducing effectiveness could be expected by soil amendment treatments for rice cultivation.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.4-11
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• 2007

There have been increasing concerns about decreasing crop productivity due to salt accumulation in greenhouse soils. The objective of the study was to investigate the impact of rice straw and woodchip application to a salt accumulated greenhouse soil on crop productivity and soil quality. The application of rice straw (RS) and woodchip (W) increased tomato yield and decreased blossom-end rot, and increased yield of Chinese cabbage compared with standard recommended fertilization ($204-103-122kg\;ha^{-1}\;N-P_2O_5-K_2O$ for tomato and $222-64-110kg\;ha^{-1}\;N-P_2O_5-K_2O$ for Chinese cabbage), while less soil residual nitrate, phosphatephosphorus, and potassium. In addition to the organic material application, fertilization reduction based on soil testing may also contribute to relatively low level of soil residual nutrients. Application of the organic material reduced soil bulk density presumably because of improved soil aggregation and structure, and increased biomass C and dehydrogenase activity. In comparison to rice straw, woodchip application resulted in higher crop yield, less amount of soil residual nitrate and lower soil EC, and greater biomass and dehydrogenase activity. The results obtained in this study indicateshowed that woodchip amendment along with reduced fertilization based on soil testing can be one of essential management practices for salt accumulated greenhouse soils.

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.465-476
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• 2023

This study introduces the development of a precast concrete double-wall, applicable to basement construction in apartment buildings. Unlike traditional precast concrete double walls, the developed double-wall doesn't require specialized manufacturing equipment such as a lathe. The constructability of these advanced technologies was validated through a full-scale mock-up test using the precast concrete double wall. The test specimens were constructed to represent a structural wall with a thickness of 250mm. It was observed that the quality of the in-situ concrete, filled between two single panels of 110mm thickness each, was excellent. The construction efficiency of the developed double-wall system for basement construction in an apartment building was also examined. Expert interviews about installation times of precast concrete elements were conducted to evaluate the speed of the basement floor's installation. The results showed that installation of precast concrete elements, including the proposed double walls, could be completed within 20 to 29 days for a basement in an apartment building. This indicates a three-fold increase in construction efficiency compared to traditional methods relying on in-situ casting.

• KSBB Journal
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• v.15 no.2
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• pp.125-133
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• 2000

Specific carotenoids and astaxanthin biosynthesis power of Phaffia rhodozyma mutant 876, which was obtained after NTG a and UV treatments, was higher than those of the wild type by 40% and 50%, respectively. The mutant strain did not show t the catabolite repression even at 22% (w/v) glucose concentration. The optimum C{N ratio was 2.0, and the optimum t temperature and initial pH were $22^{\circ}C$ and 6.0, respectively. 80th cell growth and astaxanthin formation decreased drastically a as the fermentation temperature was increased over $22^{\circ}C$, whereas they were comparable in the pH range between 5.0 and 7 7.0. Inoculum size did not affect the final cell density nor the carotenoids biosynthesis, and 3%(v/v) was selected as optimal. H Higher dissolved oxygen concentration facilitated astaxanthin biosynthesis, and aeration rate of 1.0 v/0/m and agitation speed of 400 rpm were selected as optimum. The final cell dens때 of 43.3 g/L and the volumetric astaxanthin and carotenoids concentrations of 110.6 mg/L and 149.4 mg/L, respectively, were obtained. The specific carotenoids concentration was 3.45 m mg{g-yeast(dry). Yx/s and Yp/s values of 0.37 and 1.08 were obtained. The result of this study will provide basic information u useful for mass production of astaxanthin from P. rhodozyma fermentation.

• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.643-652
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• 2002

Data were consisted of the ten body measurements (withers height, rump height, body length, chest depth, chest width, rump width, rump length, thurls width, hipbone width and chest girth) of 642 steers (Korean cattle), which was entered in the National Beef Quality Contest hosted by the Korea Animal Improvement Association from 1997 to 2001. A principal components analysis was used to classify the body types of the steers, and estimate the correlations between carcass traits and principal components for the body measurements of the first, second, third and fourth period, respectively. The first principal component of body measurements at the first, second, third and fourth period accounted for 76.0%, 83.0%, 72.7% and 57.4% of the total variance, respectively. The sum of first, second and third principal component at each period accounted for 86.69%, 90.49%, 84.62% and 77.26% of the total variance, respectively. At each period, all the first principal component of the body measurements were positive and it generally showed large framed body shape. The size of body was influenced mostly by chest depth(0.328${\sim}$0.339) and rump length(0.325${\sim}$0.341). The second, third and fourth principal component at the each period were various. There were positive correlations between principal components index of each period and carcass traits such as carcass weight(0.539${\sim}$0.755), average daily gain(0.256${\sim}$0.564), backfat thickness(0.227${\sim}$0.280), and eye muscle area(0.187${\sim}$0.344). The correlation with yield grade index(－0.246${\sim}$－0.110), however, was negative. The correlation with marbling score(0.066${\sim}$0.099) was low or statistically insignificant. According to principal component indexes of the second, third, and fourth components, the correlations with the carcass traits were various. There were no large differences between the correlations of the single body measurement trait with the carcass traits and the correlations of the first principal component indexes with the carcass traits.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.517-535
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• 2007

Two distinctive Mesozoic hydrothermal systems occurred in South Korea: the Jurassic/Early Cretaceous(ca. $200{\sim}130$ Ma) deep-level ones during the Daebo orogeny and the Late Cretaceous/Tertiary(ca. $110{\sim}45$ Ma) shallow hydrothermal ones during the Bulgugsa event. The Mesozoic hydrothermal system and the metallic mineralization in the Korean Peninsula document a close spatial and temporal relationship with syn- to post-tectonic magmatism. The calculated ${\delta}^{18}O_{H2O}$ values of the ore-forming fluids from the Mesozoic metallic mineral deposits show limited range for the Jurassic ones but variable range for the Late Cretaceous ones. The orogenic mineral deposits were formed at relatively high temperatures and deep-crustal levels. The mineralizing fluids that were responsible for the formation of theses deposits are characterized by the reasonably homogeneous and similar ranges of ${\delta}^{18}O_{H2O}$ values. This implies that the ore-forming fluids were principally derived from spatially associated Jurassic granitoids and related pegmatite. On the contrary, the Late Cretaceous ferroalloy, base-metal and precious-metal deposits in the Taebaeksan, Okcheon and Gyeongsang basins occurred as vein, replacement, breccia-pipe, porphyry-style and skarn deposits. Diverse mineralization styles represent a spatial and temporal distinction between the proximal environment of subvolcanic activity and the distal to transitional condition derived from volcanic environments. The Cu(-Au) or Fe-Mo-W deposits are proximal to a magmatic source, whereas the polymetallic or the precious-metal deposits are more distal to transitional. On the basis of the overall ${\delta}^{18}O_{H2O}$ values of various ore deposits in these areas, it can be briefed that the ore fluids show very extensive oxygen isotope exchange with country rocks, though the ${\delta}D_{H2O}$ values are relatively homogeneous and similarly restricted.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1419-1425
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• 2013

The aim of this study was to investigate the method validation for the determination of eleutherosides (B and E) and ${\beta}$-glucan in Acanthopanax (A.) koreanum. This medicinal plant reportedly mainly included eleutherosides which exhibit the pharmacological effects, and ${\beta}$-glucan substantially enhances the function of the immune system by activating macrophages. The specificity, linearity, precision, accuracy, limit of detection (LOD, S/N=3), and limit of quantification (LOQ, S/N=10) were measured by HPLC and enzymatic methods. Our results showed that the coefficient of calibration correlation ($R^2$) for eleutheroside B and E were 0.9997 and 0.9999, respectively. The limits of detection (LOD) for eleutheroside B and E were $0.050{\mu}g/mL$ and $0.025{\mu}g/mL$, respectively. The recovery rate of eleutheroside B and E were revealed in the high range of 100.66~110.04% and 94.26~111.62%, respectively. The inter-day precision of eleutheroside B and E in the root and stem in A. koreanum were 1.4~5.0% and 1.1~2.5%, respectively. The intra-day precision of eleutheroside B and E in the root and stem in A. koreanum were 2.8~2.9% and 0.4~1.1%, respectively. Furthermore, the inter-day and intra-day precision of ${\beta}$-glucan in the stem, leaf, and fruit of A. koreanum were 1.32~5.67% and 8.01~11.76%, respectively. In conclusion, the methods were validated for the detection of eleutherosides and ${\beta}$-glucan in A. koreanum.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.101-108
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• 1993

$TiO_{2}$/Se : Te heterojunction for color sensor has been fabricated by RF reactive sputtering and thermal evaporation methods onto glass substrate. The optimum deposition condition of $TiO_{2}$ films was such that RF power was 120 W, substrate temperature was $100^{\circ}C$, oxygen concentration was 50%, working pressure was 50 mTorr for the $TiO_{2}$ film thickness of $1000{\AA}$. In this case, the optical transmittance of $TiO_{2}$ film at 550 nm-wavelength was 85%, resistivity was $2{\times}10^9{\Omega}{\cdot}cm$, refractive index was 2.3, and optical bandgap was 3.58 eV. The composition ratio of 0 to Ti by AES analysis was 1.7. When $TiO_{2}$ films were annealed at $400^{\circ}C$ for 30 min. in $O_{2}$ ambient, the optical transmittance of $TiO_{2}$ films at the wavelength range of $300{\sim}580$ nm was improved from 0 to 25%. When Se : Te films were annealed at $190^{\circ}C$ for 1 min., photosensitivity under illumination of 1000 lux was 0.75. The optical bandgap of Se : Te films was 1.7 eV. The structures of Se : Te films were the hexagonal with (100) and (110) orientation. The spectral response of a-Se was improved by the addition of Te, especially in the long wavelength region. The $TiO_{2}$/Se : Te heterojunction showed wide spectral response, and more improved one than that of a-Si film in the blue light region.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.254-265
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• 2021

As a result of measuring the polyphenol content of Humulus japonicus (HJ) extract according to the collection time and extraction solvent, bothhot water extract and 70% ethanol extract were collected and extracted in June, and the polyphenol content was high. When the harvesting time was the same, the polyphenol content of the ethanol extract was higher than that of the hot water extract. As a result of measuring the antioxidant activity of HJ extract by measuring electron-donating ability, SOD-like activity, and ABTS radical scavenging ability, HJ6E, which has the highest polyphenol content, showed the highest activity. In addition, in the case of the extract collected in August, the polyphenol content was similar. However, the antioxidant activity of the ethanol extract was high, sothe antioxidant activity remained high when extracted with 70% ethanol. As a result of measuring tyrosinase inhibitory activity for evaluating skin whitening activity, HJ6W did not show any activity. The activity at the highest concentration was 16.18% for HJ8W, 8.07% for HJ6E, and 14.7% for HJ8E. Therefore, the content of ingredients showing skin whitening activity was higher in August than in June. In the elastase inhibitory activity for evaluating the anti-wrinkle activityof the skin, the ethanol extract showed very little activity, and the hot water extract did not. In addition, since all extracts do not show astringent activity, it is judged that it is not appropriate to use HJ as a functional ingredient for preventing wrinkle formation. As a result of measuring the cell viability of HJ6E, which showed the highest polyphenol content and antioxidant activity, it showed a cell proliferation effect at low concentrationsbut strong cytotoxicity at concentrations above 50 ㎍/mL. In the case of the NO production inhibitory ability, as the concentration increased, the NO production of Raw 264.7 was suppressed. Theamount of NO production at 1,000 ㎍/mL decreased to 40.7%. However, whether these results are due to cytotoxicity or the extract's efficacy is a part that requires further research.

• Journal of Biosystems Engineering
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• v.10 no.1
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• pp.54-68
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• 1985

It is desirable to collect the solar thermal energy at relatively high temperature in order to minimize the size of thermal storage system and to enlarge the scope of solar thermal energy utilization. So far the concentrating solar collector has been developed to collect solar thermal energy at relatively high temperature, but it has some difficulties in maintaining the volumetric body of solar collector for long term utilization. On the other hand, the flat-plate solar collector has been developed to collect the solar thermal energy at low temperature, and it has advantages in maintaining the system for long term utilization, since it's thickness is thin and not volumetric. In this study, to develop a solar collector that has both advantages of collecting solar thermal energy at high temperature and fixing conveniently the collector system for long term period, a cylindrical parabolic concentrating solar collector was designed, which has two rows of parabolic reflectors and thin thickness such as the flat-plate solar collector, maintaining the optical form of concentrating solar collector. The characteristics of the concentrating parabolic solar collector newly designed was analysed and the results are summarized as follows; 1. The temperature of the air enclosed in solar collector was all the same as $50^{\circ}C$ in both cases of the open and closed loop, and when the heat transfer fluid was not circulated in tubular absorber, the maximum surface temperature of the absorber was $118-120^{\circ}C$, this results suggested that the heat transfer fluid could be heated up to $118^{\circ}C$. 2. In case of longitudinal installation of the solar collector, the temperature difference of heat transfer fluid between inlet and outlet was $4^{\circ}-6^{\circ}C$ at the flow rate of $110-130{\ell}/hr$, and the collected solar energy per unit area of collector was $300-465W/m^2$. 3. The collected solar energy per unit area for 7 hours was 1960 Kcal/$m^2$ for the open loop and 220 Kcal/$m^2$ for the closed loop. Therefore it is necessary to combine the open and closed loop of solar collectors to improve the thermal efficiency of solar collector. 4. The thermal efficiency of the solar collector (C.P.C.S.C.) was proportional to the density of solar radiation, indicating the maximum thermal efficiency ${\eta}_{max}=58%$ with longitudinal installation and ${\eta}_{max}=45%$ with lateral installation. 5. The thermal efficiency of the solar collector (C.P.C.S.C.) was increased in accordance with the increase of flow rate of heat transfer fluid, presenting the flow rate of $110{\ell}/hr$ was the value of turning point of the increasing rate of the collector efficiency, therefore the flow rate of $110{\ell}/hr$ was considered as optimum value for the test of the solar collector (C.P.C.S.C.) performance when the heat transfer fluid is a liquid. 6. In both cases of longitudinal and lateral installation of the solar collector (C.P.C.S.C.), the thermal efficiency was decreased linearly with an increase in the value of the term ($T_m-T_a$)/Ic and the increasing rate of the thermal efficiency was not effected by the installation method of solar collector.