• Journal of Korean Society of Forest Science
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• v.76 no.1
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• pp.33-40
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• 1987

Simulated acid rain (pH 4.0, pH 2.0) containing sulfuric and nitric acid in the ratio of 60:40 (chemical equivalent basis) diluted with underground water, and underground water (pH 6.5) as control were treated on potted Pines koraiensis seeds during the growing season (May 1 to August 31) in 1985. The regime of artificial acid rain, in terms of spray frequency and amount per plot, was simulated on the basis of climatological data averaged for 30 years of records. The seedling growth, contents of chemical substances in needles and chemical properties of the tested soil were compared among the various pH levels of acid rain on October 31, 1985. Following results were obtained. 1. With decreasing pH levels of acid rain, S and $K_2O$ contents in leaf tissue were increased, but MgO and $P_2O_5$ contents were decreased. 2. Soil pH was dropped, and exchangeable aluminum content in the tested soil was dramatically increased as the pH levels of acid rain decreased. 3. Exchangeable calcium, magnesium, potassium contents, and base saturation degree of the soil were significantly decreased with decreasing pH levels of acid rain. 4. Sulfate concentrations in the soil were significantly increased as rain pH decreased, but total nitrogen and available phosphate contents were not influenced by acid rain.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.286-292
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• 1991

This study was carried out to investigate in influence of inoculation B. sp. and lime types on nutrient content of peanut seed, and the correlation between nutritient contents in seed and plant. 1. Inoculated B. sp., content of crude protein, phenylalanine, isoleucine, cystine, histidine, aspartic acid, serine, and alanine in seed were increased significantly, but that of crude fat was decreased. 2. The content of crude fat was the highest without lime, glutamic acid was the highest with calcium sulfate, valine, phenylalanine, isoleucine, leucine, lysine, aspartic acid, serine, glycine and alanine with slaked lime, and histidine with calcium carbonate. 3. The content of crude protein in seed was negatively correlated with that of crude fat. The contents of chlorophyll, allantoin, ammonia, free amino acid, T-N, $P_2O_5$, and CaO in leaf at 100 days after sowing were positively correlated with the content of crude protein and various kinds of amino acid in seed, but negatively with the content of crude fat. The content of nitrate in leaf at 100 days after sowing showed the result of contrary tendency.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.67-72
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• 2022

Concrete prevents corrosion of reinforcing bars due to its strong alkalinity. However, in the sea, strong alkali components with a pH of 12 to 13 are eluted, which adversely affects the ecological environment and growth of marine organisms. In this study, the mechanical properties and durability of the low alkali mortar were evaluated for the development of a low alkali mortar for the 3D printed artificial reefs. As a result of evaluation of strength characteristics, the α-35 mixture, which were produced with fly ash, silica fume and α-hemihydrate gypsum, satisfied the strength requirement 27 MPa in terms of compressive strength. As a result of pH measurement, it was found that mixing with alpha-type hemihydrate gypsum resulted in minimizing pH due to the the formation of calcium sulfate instead of calcium hydroxide production. As a result of the chloride ion penetration resistance test, the α-35 mixture exhibited the best performance, 3844C. As a result of measuring the length change over time, the α-35 mixture showed the shrinkage 33.5% less compared to the Plain mix.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E1
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• pp.29-39
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• 2003

The 10-day interval basis measurements of precipitation samples at Yangyang, the rural and coastal area on the eastern coast of the Korea peninsula were accomplished for understanding the precipitation chemistry and the temporal variations of major ions September 1991 to February 1997. The precipitation was slightly acidic, and 37% of the samples in winter were pH less than 4.5. The concentrations of cations were found on the order $Na^+\;>\;{NH_4}^+\;>\;Ca^{2+}\;>\;Mg^{2+}\;>\;K^+$ and those of anions followed the pattern $Cl^-\;>\;{SO_4}^{2-}\;>\;{NO_3}^-$. Neglecting sea salt components, the major ions controlling precipitation chemistry were nss-${SO_4}^{2-}$ and ${NO_3}^-$ in anion and ${NH_4}^+$ and nss-$Ca^{2+}$ in cation. Concentrations of these ions were lower than those measured at urban sites in Korea, but were higher than those measured in Japan. Most of nss-${SO_4}^{2-}$ and ${NO_3}^-$ were neutralized by ammonia and calcium species, especially alkaline soil particles in spring and ammonia gas in other seasons. Considering also the annual value of ［nss -${SO_4}^{2-}$］/［${NO_3}^-$］ ratio of 2.62 and the neutralizing factors, ammonium sulphate compounds were dominant. Annual mean concentrations of these ions showed relatively small fluctuations, while larger seasonal variations were observed with higher levels in spring and winter. Precipitation amount, influence extent of acidic gases and alkaline particles long-range transported from China continent, and energy consumption pattern in each season might be able to explain this seasonal trend.sonal trend.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.551-564
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• 2003

Statement of problem : Magnesium oxide may increase pH of alginate, and supply magnesium ions to the polymerization reaction of alginate. Purpose : This study was designed to evaluate the influence of incorporation of magnesium oxide to alginate composition. Material and Method : Seven kinds of experimental alginates were prepared and used for the experiments. Components with unchanging concentrations were sodium alginate 15%, calcium sulfate 14%, sodium phosphate 2%, and zinc fluoride 3%. Contents of magnesium oxide were varied as 0%, 1%, 2%, 3%, 4%, 5%, 6%. Diatomaceous earth were added to each experimental groups as balance to be 100%. Control group was a MgO 0% group. Working time, setting time, elastic recovery strain in compression, compressive strength and tear resistance were measured were measured. Sample size for each groups were 10. Arithmetic means were used as each groups representative values. Regression test between MgO contents and results, Duncan's multiple range test, and One-way ANOVA test were done between groups at level of 0.05. Results : 1 Magnesium oxide made the working time and setting time as longer(p<0.0001). 2 Magnesium oxide did not alter the elastic recovery(p>0.05). 3. Magnesium oxide contents between 2% and 4% exhibited the lowest strain in compression on alginates(p<0.0001). 4. Magnesium oxide made the compressive strength and the tear resistance stronger(p<0.0001). Conclusion : These results mean that setting time of alginate maybe controlled and that mechanical properties maybe improved by the incorporation of magnesium oxide into alginate, without any reduction of elasticity.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.405-410
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• 2015

The objective of this study was to evaluate the effects of sequential applications of ${\varepsilon}$-polylysine (EPL) or lauramide arginine ethyl ester (LAE) sprays followed by an acidic calcium sulfate (ACS) spray on inoculated chicken carcasses to reduce Salmonella (Salmonella enterica serovars including Salmonella typhimurium and Salmonella enteritidis) contamination during 6 days of storage ($4.4^{\circ}C$). Secondly, reductions of the resident microflora were studied on uninoculated chicken carcasses following the sequential application of the treatments, chilling and 10 days of storage at $4.4^{\circ}C$. The treatment of Salmonella inoculated carcasses with 300 mg/L EPL followed by 30% ACS (EPL300-ACS30) sprays reduced Salmonella counts initially by 1.5 log cfu/mL and then by 1.2 log cfu/mL (p<0.05) following 6 days of storage at $4.4^{\circ}C$. Likewise, 200 mg/L LAE followed by 30% ACS (LAE200-ACS30) treatment reduced initial Salmonella counts on poultry carcasses by 1.8, 1.4 and 1.8 log cfu/mL (p<0.05), respectively, after 0, 3, and 6 days storage. Immediately after the treatments, EPL300-ACS30 and LAE200-ACS30 both reduced Escherichia coli counts significantly by 2.6 and 2.9 log cfu/mL, respectively. EPL300-ACS30 and LAE200-ASC30 were effective in lowering psychrotroph counts by 1 log cfu/mL on day 10 when compared to the control and distilled water treatments. This study demonstrated that EPL300-ACS30 and LAE200-ACS30 were effective in reducing Salmonella on inoculated chicken carcasses both after treatment and during the storage at $4.4^{\circ}C$ for up to 6 days. In addition, reductions in psychrotroph counts indicated that these treatments might have the potential to increase the shelf-life of poultry carcasses.

• Journal of Life Science
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• v.11 no.1
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• pp.7-10
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• 2001

Nonactin is the parent compound of a group of ionophore antibiotics, that known as the macrotetrolides. In previous report, in th course of screening superoxide radical-generating compounds from microbial sources, we first screened Streptomyces viridochromogenes JM-4151 that produces nonactin. It was proved that nonactin is superoxide radical-producing compound. In present study, we examined the optimal culture conditions of nonacin. Th optimal culture conditions for nonactin production were as follows: 1% soluble starch, 1% yeast extract, 0.2% ammonium nitrate, 0.06% magnesium sulfate, 0.2% calcium carbonate, initial pH 7.0 at 28$^{\circ}C$ for 96 h. The highest nonactin production was achieved in the production medium of initial pH7.0 at 28$^{\circ}C$ for 96h. The threshold level of dissolved oxygen was found to be above 33.2% at 28$^{\circ}C$ when 1% soluble starch was used as a carbon source. These results suggest that S. viridochromogenes JM-4151 might be a possible strain for industrial nonactin producer.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.5
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• pp.1285-1290
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• 2007

The present study aims to identify and characterize genes that cause differen genes between non-responders and responders to electroacupuncture (EA) on mechanical allodynia following peripheral nerve injury. Under sodium pentobarbital anesthesia, animals were subjected to unilateral transection of the superior caudal trunk at the level between S1 and S2 spinal nerves. EA stimulation (2Hz, 0.3 ms, 0.2-0.3 mA) was delivered to Zusanli (ST36) for 30 min 2 weeks after the surgery. The degree of mechanical allodynia was assessed quantitatively by touching the tail with von Frey hair (2.0 g) at 10 min intervals. The rats, which showed an EA-induced decrease of response frequencies under 10 %, were classified as non-responders and those displaying an EA-induced decrease of response frequencies 20 % or more were classified as responders. Results from oligonucleotide microarray, to which cDNAs from the spinal dorsal horn (DH) were applied, showed that hemoglobin beta chain complex and chondroitin sulfate proteoglycan-5 decreased and limbic system-associated membrane protein increased in the non-responder group, whereas calcium-independent alpha-Iatrotoxin receptor homolog-3 increased in the responder group. These results suggest that The functional abnormality of molecules regulating cell adhesion, intracellular signal transduction and cell differentiation in the spinal DH may be involved in the anti-allodynic effect of EA.

• Resources Recycling
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• v.15 no.3 s.71
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• pp.20-29
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• 2006

This study was carried out for to recover the purified crystalline gypsum from phosphogypsum by means of using it's crystallographical Properties. The dehydration of hydrated phosphogypsum to $\alpha$-hemihydrate is completed with the 2 hours treatment of it in $99^{\circ}C$ waterrs. The purified crystalline gypsum having the maximum size of $200{\mu}m$ was obtained by 325# wet screening after recrystallization of the $\alpha$-hemihydrate gypsum at the condition of $Na_2SO_4$ 10 wt%, slurry density 20%, $pH\;5{\sim}6,\;65^{\circ}C$ and 4hr. In this process, the yield of gypsum was 93.9% and its grade was 99%.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.1
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• pp.11-23
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• 1998

The purpose of this study was to survey chemical distribution of inorganic elements and ions in the submicron particles, to characterize qualitatively emitting sources by factor analysis, and finally to reveal existing patterns in terms of chemical compounds by a stepwise multiple regression analysis. Total of 141 samples were collected by a cascade impactor from 1989 to1996. Fifteen chemical species (Al, Ba, Cd, K, Pb, Cu, Fe, Ni, $Cl^-, NO_3^-, SO_4^{2-}, K^+, Mg^{2+}, Ca^{2+}, and Na^+$) were characterized by AAS and IC. The study showed that average seasonal levels of submicron particulate matters $(d_p<0.43 \mum)$ were 18.7 $\mug/m^3$ in spring, 15.5 $\mug/m^3$ in summer, 15.7 $\mug/m^3$ in fall, and 24.5 $\mug/m^3$ in winter, respectively. All of the anion concentrations in the particle were highest in the winter season. By applying a factor analysis, 5 source patterns were qualitatively obtained, such as sulfate related source, nitrate related source, oil burning source, calcium related source, and coal combustion source. Finally, when applying a stepwise multiple regression analysis, the results clearly showed that $Na^+ and Ca^{2+}, K^+ and Ca^{2+}, NO_3^-$ and relative humidity, $Cl^-$ and ambient temperature, $Ca^{2+} and Cl^-, Mg^{2+} and SO_4^{2-}, Na^+ and NO_3^-, and Ca^{2+} and NO_3^-$, respectively, are negatively contributed to each other. As a result of those statistical analysis, we could suggest that some chemical compounds in the submicron particles such as$NaNO_3, MgSO_4, Ca(NO_3)_2, and CaCl_2$ may not exist on the filter as final composing products; however, other compounds may possibly exist in the form of $Mg(NO_3)_2, CaSO_4, Na_2SO_4, K_2SO_4, MgCl_2, NaCl, and KCl$. Thus, it must be necessary to identify differences between the results of above statistical analysis and of the real world by laboratory experiments.