• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.363-370
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• 2016

Lightweight geopolymers are more readily produced and give higher fire resistant performance than foam cement concrete. Lowering the density of solid geopolymers can be achieved by inducing chemical reactions that entrain gases to foam the geopolymer structure. This paper reports on the effects of adding different concentrations of aluminum powder on the properties of cellular structured geopolymers. The apparent density of lightweight geopolymers has a range from 0.7 to $1.2g/m^3$ with 0.025, 0.05 and 0.10 wt% of a foaming agent concentration, which corresponds to about 37~60 % of the apparent density, $1.96g/cm^3$, of solid geopolymers. The compressive strength of cellular structured geopolymers decreased to 6~18 % of the compressive strength, 45 MPa of solid geopolymers. The microstructure of geopolymers gel was equivalent for both solid and cellular structured geopolymers. The workability of geopolymers with polyprophylene fibers needs to be improved as in fiber-reinforced cement concrete. The lightweight geopolymers could be used as indoor wall tile or board due to fire resistance and incombustibility of geopolymers.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.611-619
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• 1998

This study was carried out to examine the effects of soil acidification on growth and nutrient status of 2 - year - old Pious densiflora Sieb. et Zucc. seedlings grown for 120 days in brown forest soils acidified with $H_2SO_4$ solution with or without leaching rations from the soil. The concentrations of A1 in the acidified soils increased with increasing amount of $H^+$ added to the soil. The total dry weight of the seedlings was decreased by the addition of the $H_2SO_4$ solution. The increase of Al concentration in the belowground part resulted from the decreased concentration of essential mineral elements such as Ca and Mg in the aboveground part. In addition, a strong positive correlation(r=0.96, p<0.001) was observed between the dry weight of the seedlings and the molar (Ca+Mg+K)/A1 ratio of the soil solution. When the molar (Ca+Mg+K)/Al ratio was approximately 7.0, the dry weight of the seedlings began to decrease compared with that of the seedlings in the control treatment. The seedlings with the molar (Ca+Mg+K)/Al ratio of 1.0 resulted from approximately 40% growth reduction compared with the control value. The results suggest that the molar (Ca+Mg+K)/Al ratio of the soil solution may be a useful indicator for assessing the critical load of acid deposition.

• The Journal of the Petrological Society of Korea
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• v.24 no.2
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• pp.77-90
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• 2015

The fission track registration techniques for accurate determinations of uranium in solid- and liquid-state geological materials were recommended and their applicability were examined. The determination of uranium can be achieved by optical counting of neutron-induced fission tracks of $^{235}U$ registered on solid-state track detectors under high magnification. In a dry registration method using powdered pellets of rocks (e.g., granite and coal) showing good uranium-affinity, it was not easy to decide an overall mean concentration over the total sample owing to track-clusters caused by frequent presence of uranium-bearing minerals. Separate scanning for homogeneous and track-clustered parts may be an alternative choice. Assuring the homogeneity over the whole sample, high reproducibilities were confirmed both from duplicate detections using mica and Lexan polycarbonate detectors and from multiple measurements at different thermal neutron fluences. The wet registration method using sealed quartz tubes is recommended to overcome the common heterogeneity in uranium concentrations of $10^1ppm$ and more. Adopting the wet registration, the uranium homogeneity was recovered below the $10^0ppm$ level and the lower detection limit was proved to reach without difficulty the $10^2ppb$ (i.e. $ng\;g^{-1}$) level.

• Food Science and Preservation
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• v.15 no.1
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• pp.125-132
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• 2008

This study investigated the cremical components of 1he s1aks anI leaves of Sasa borealis Makino, and the antioxidative activities, nitrite scavenging levels, and antimicrobial activities of extracts of the stalks and leaves. The moisture contents of stalks and leaves were 59.87%(w/w) and 28.79%(w/w), the crude protein levels 2.09%(w/w) and 6.33%(w/w), the crude fat concentrations 1.21%(w/w) and 3.43%(w/w), and the ash levels 0.99%(w/w) and 3.76%(w/w), respectively. The major mineral components were K, Na, Mg and Mn; and the K contents of stalks and leaves were the highest amongst the minerals tested, at 350.27 mg% and 639.60 mg%, respectively. The principal organic acids of stalks and leaves were acetic acid, citric acid and succinic acid, and the organic acid content of leaves was higher than that of stalks. The antioxidative activity of stalk extracts was higher than that of leaves, and the antioxidative activities of ethanol extracts were higher than those of hot water extracts. The 0.5%(v/v) ethanol stalk extracts showed stronger antioxidative effects than did the 0.02%(w/v) butylated hydroxyanisole. All extracts showed nitrite scavenging activities, and hot water extracts from stalk showed the highest activities. Hot water extracts showed antimicrobial activities against all bacterial strains tested, and ethanol extracts from leaf showed strong antimicrobial activities against most bacteria, except Listeria monocytogenes and Salmonella typhymurium. The antimicrobial activities of most stalk and leaf extracts were higher than those obtained using 1.0%(w/v) sorbic acid.

• Journal of Life Science
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• v.22 no.12
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• pp.1704-1711
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• 2012

Three mold strains, Aspergillus oryzae (A. oryzae), Aspergillus kawachii (A. kawachii), and Monascus purpureus (M. purpureus), were tested for fermentation of Acanthopanax senticosus (A. senticosus) leaf, root, stem, and fruit powders. The fermented A. senticosus materials were then tested for bioactive materials (phenolic compounds, flavonoids, mineral and fatty acid) and biological activities (DPPH free radical scavenging activity, reducing power, and tyrosinase inhibition activity). The highest concentrations of phenolic compounds and flavonoids were NFASL at 4.11% and MPASL at 2.30%, respectively. Major minerals were Ca, K, Mg and Mn. Major fatty acids in fermented A. senticosus powders were palmitic, linolenic, and stearic acids. DPPH radical scavenging activity was slightly stronger in non-fermented than in fermented A. senticosus. Tyrosinase inhibition activity was stronger in fermented A. senticosus than in NFAG. The Fe/Cu reducing powers were stronger in non-fermented A. senticosus than in any of the fermented A. senticosus materials. Overall, the study provides basic data for understanding the biological activities and chemical characteristics of A. senticosus fermented by molds for the development of functional foods.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.320-326
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• 1997

In order to elucidate the degradation characteristics of the herbicide imazapyr in soil, mineralization to $^{14}CO_2$and adsorption were investigated using eight types of soils with the different physico-chemical properties. The results obtained were as follows: 1. During the incubation period of 12 weeks after the treatment of imazapyr, the amounts of $^{14}CO_2$ evolved from 8 types of soils with different properties ranged from 1.5 to 4.9% of the originally applied $^{14}C$ activities. Soil C, G, and H with low pH and high organic matter showed low $^{14}CO_2$evolution, whereas soil B and D with high pH and low organic matter did high $^{14}CO_2$ evolution. 2. Time for reaching the equilibrium concentrations in the adsorption experiment of imazapyr in soils was about 3 hours at $25^{\circ}c$ in soil C, D, G, and H. Imazapyr was adsorbed in the range of 0.25${\sim}$28.32% in soils with different physico-chemical properties. Among the soil parameters, organic matter content was the most influential in imazapyr adsorption on soil. The Freundlich adsorption coefficient $(K_f)$ increased 5.5 to 25.6 times as organic matter content increased 2.0 to 21.3 times. Hence it seems that the extent to which soil organic matter contributes to imazapyr adsorption is greater than that of clay mineral. $K_f$ values for the soils tested were 0.44, 0.08, 0.65, and 2.05 in soil C, D, G, and H, respectively. In all the soils tested, $K_f$ values had a strong resemblance to K_$K_d$.

• Journal of Bio-Environment Control
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• v.6 no.1
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• pp.27-33
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• 1997

This experiment was carried out to investigate the effects of limited nutrient supply during 21 days before and after pollination stage on the growth, fruit quality and nutrient uptake of muskmelon in rockwool culture. Muskmelon, cv. Earl's Favorite seeds sowed on rockwool cube and transplanted on rockwool slab($90\times15\times7.5cm$) when 2 to 3 true leaf appeared on Sep. 6, 1991. Three kinds of nutrient composition recommended by Shizuoka university, combinated with the composition of Otsuka house A and composition Shizuoka III. One half of calcium nitrate(Ca(NO$_3$)$_2$.4$H_2O$) for limiting nitrogen supply during 21 days was treated and then fertigated the nutrient composition recommended by Shizuoka university up to harvest time. Trickling nozzles(Netafim Co. Israel) were used for fertigation of nutrient solution and noncirculating system was employed. Temperature was maintained $18^{\circ}C$ in night but 23 to $25^{\circ}C$ for 10 days after pollination for softening the fruit. The drainage ratio of nutrient solution was adjusted 20 to 30 percent. Fertigated and drained amount, and the pH and EC of nutrient solution were recorded. The concentrations of mineral elements including N, P, K, Ca, and Mg were analyzed and compared among treatments. In both autumn and winter cultivation, the limitation of nutrient supply by adjustment of nutrient composition(NO$_3$-N : 8meㆍ$\ell^{-1}$) caused the nutrient deficiency in muskmelon plant due to the limited nutrient supply. After pollination nutrient limitation by the lowering the nitrate retarded the over thickening of upper leaves of muskmelon but plant height and fresh weight of fruit were higher in the plot of nonlimited nutrient supply. The phenomena were attributed to the differences of the amount of nutrient uptake due to the limited time of nutrient solution, duration of nutrient supply and concentration of nutrient solution. These results suggested that increasing nutrient supply in the pollination stage was favorable for better appearance of fruit and improving fruit quality. Further trials would be required for the incre-ment of sugar degree of muskmelon grown in rockwool.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.3
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• pp.116-124
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• 2000

Geochemical and isotopic analyses were carried out to investigate hydrochemical characteristics, source of carbon species in the carbonated waters in South Korea. Most Korean carbonated waters from different geologic settings are characterized by a Ca-HCO$_3$type with a relatively low pH range from 5.3 to 6.3 (avg. 6.0). The concentrations of cations and anions in the carbonate waters are in the order of Ca$^{2＋}$>Na$^{＋}$>Mg$^{2＋}$>Si$^{4＋}$>Fe$^{2＋}$>K$^{＋}$ and HCO$_3$$^{－}$>SO$_4$$^{2－}$>Cl$^{－}$, respectively. The HCO$_3$$^{－}$ ion is more enriched in the carbonated water from the sedimentary rock and granitic rock of Mesozoic age in the Gyungsang basin(GII) and the Precambrian metamorphic rock and Jurassic granitic rocks of the Gyunggj massif in the Gangwon province(GⅠ) than those of the meta-sedimentary rock and granite in the Ogcheon zone(GⅢ). Based on the oxygen and hydrogen isotopic data, the carbonated waters are derived from the meteoric water, showing apparent latitude and altitude effects. The $delta$$^{13}$C values of carbon species in the carbonated water are in between -6.23 and 0.0 $textperthousand$, suggesting inorganic source of carbon originated from the carbonate mineral and carbonate rock in the aquifer.

• Korean journal of food and cookery science
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• v.24 no.5
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• pp.691-698
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• 2008

In this study, we assessed the quality characteristics of soybean curds (tofu) prepared with Mesangi (Capsosiphon fulvescens) powder (0, 2, 4, 6%, w/w) were investigated. The yields of the curds containing Mesangi were higher than those of the control, and the yield increased with increasing quantities of Mesangi powder. The most abundant mineral in Mesangi tofu was calcium, followed by magnesium. The Mesangi tofu had a slightly lower pH than the control. The addition of Mesangi powder to curd evidenced a significantly lower L value (lightness) and a value (redness) than was detected in the control (p<0.05). The hardness level was highest in the tofu to which 2% Mesangi powder was added. However, this level decreased with increasing concentrations of Mesangi powder. Although the 4% Mesangi tofu evidenced higher adhesiveness than was detected in the control, we noted no significant differences among the Mesangi-treated curds. The soybean curds added to which 2% Mesangi powder was added had evidenced the highest level of cohesiveness, but the tofu containing 4 and 6% Mesangi powder was significantly reduced as compared with the control and 2% Mesangi tofu. Springiness, gumminess, and brittleness were higher in the 2% Mesangi tofu than in the others (p<0.05). The soybean curds prepared with Mesangi powder evidenced a lower total plate count than the controls during over 12 days of storage.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.352-357
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• 2019

In this study, we investigated the limit temperature range which is effective for dormancy release of 'Hongro' and 'Fuji' apples during the endodormancy period. The germination rate was 50% or more in all treatments except of 'Hongro' $-5^{\circ}C$ treatment. The germination rate of 'Fuji' was 86.3% at the temperature of $-5^{\circ}C$. The concentrations of carbohydrate and mineral components were significantly different between treatments but did not show any tendency or specific change. However, the sorbitol contents of 'Hongro' $-5^{\circ}C$ treatment were higher at 29.62 mg/g than those of 'Fuji', which was not affected for dormancy release. The results of hormone analysis showed that ABA(abscisic acid) and JA(jasmonic acid) in 'Hongro' $-5^{\circ}C$ treatment were respectively 176.48 and 15.72 ng/g. ABA, JA and SA(salicylic acid) contents in 'Fuji' apple tree were significantly lower than those of 'Hongro'. As a result of this study, the limit temperature range effective for dormancy release was different according to the varieties, and 'Hongro' did not affect with 30.3% of germination rate at $-5^{\circ}C$. However, 'Fuji' is 86.3% even at $-5^{\circ}C$ it was suggested that 'Fuji' had a chilling accumulation for dormancy release.