• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.243-249
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• 1975

This experiment were carried out to investigate the conditions of amylase produced by Candida muscorum in wheat bran cultures and the properties of its amylase (crude enzyme). The results obtained were as follows. 1. The optimum conditions for amylase production in wheat bran cultures were; water content 75 percent, temperature $25^{\circ}C$ and incubation time 4-7 days. 2. The production of amylase was increased about 20 percent in the medium added 0.5 percent of ammonium sulfate or ammonium chloride to wheat bran, but the production of those was decreased in the case of addition of nitrates. 3. No significant effect was found in the case of the addition of carbon source on the production of amylase. 4. The properties of liquefying amylase of the selected strain were; the optimum pH 4.2, the optimum temperature $60-65^{\circ}C$, the stable pH 3.2-6.8 and the stable heating (for 15 minutes heating) below $65^{\circ}C$. 5. The properties of saccharifying amylase of the selected strain were; the optimum pH 4.5, the optimum temperature $55^{\circ}C$, the stable pH 3.8-6.2 and the stable heating (for 15 minutes heating) below $45^{\circ}C$.

• Journal of Conservation Science
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• v.34 no.6
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• pp.459-470
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• 2018

Cellulose nitrates were used for folklore artifacts(ornamental beads and pipes in hatstrings, frames of eyeglasses, ornamental eyeglass cases, headband ornaments, and jeogori buttons) between the 19th and 20th centuries; however, they are susceptible to cracking, crazing, embrittlement, and crumbling due to deterioration. To consolidate and adhere deteriorated cellulose nitrate folklore artifacts, water-soluble acrylic emulsion adhesives were investigated. For consolidation, Plextol D 498, which has the lowest viscosity in low concentrations, was used. In adhesive films whose glass transition temperature(Tg) is lower than room temperature, the tensile stress and modulus decreased and the strain increased; therefore, the flexibility was high. The Plextol D 498 and Plextol D 498 and Dispersion K 52 films maintained their adhesiveness and flexibility after artificial-sunlight-accelerated ageing, and Plextol D 498 and Dispersion K 52 films hardly caused yellowing. Plextol D 498 was the most stable for accelerating ageing. A low concentration of Plextol D 498 emulsion resulted in the best permeability on the surface of cellulose nitrate, compared with other acrylic emulsions. To prevent ornamental hatstrings from cracking, crazing, embrittlement, and crumbling, a Plextol D 498 emulsion was used. After applying low concentrations(1%, 3%) of the emulsion to consolidate the fragments and high concentration to adhere the fragments, the ornamental hatstrings were protected from crumbling by deterioration, and their fragments were well-adhered. To preserve it from deterioration by oxygen and humidity, the treated ornament was sealed with an oxygen-barrier film using a low-humidity oxygen scavenger.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.77-90
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• 2022

Despite the decreasing trend of anthropogenic emissions in East Asia in recent years, haze days still frequently occur in spring. Atmospheric blocking, which occurs frequently in the northeastern Pacific, leads to persistent changes in large-scale circulation and blocks westerly flow in the East Asian region. During March 2019, frequent warm and stagnant synoptic meteorological conditions over East Asia were accompanied 6-7 days later by the Alaskan atmospheric blocking. The Alaskan atmospheric blocking over the period of March 18-24, 2019 led to high particulate matter (PM₁₀) severe haze days exceeding a daily average of 50 ㎍ m^-3 over the period of March 25-28, 2019 in South Korea. Although the high-PM₁₀ severe haze days were caused by warm and stagnant meteorological conditions, the regional contribution of anthropogenic emissions in eastern China was calculated to be 30-40% using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). The major regional contributions of PM₁₀ aerosols in the period of high-PM₁₀ severe haze days were as follows: nitrates, 20-25%; sulphates, 10-15%; ammonium, 5-10%; and other inorganics, 15-20%. Ammonium nitrate generated via gas-to-aerosol conversion in a warm and stagnant atmosphere largely contributed to the regional transport of PM₁₀ aerosols in the high-PM₁₀ severe haze days in South Korea.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1615-1615
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• 2001

During the past ten years, Near Infrared Spectroscopy has been successfully applied to the analysis of a great variety of agriculture products. Previous works (Morra et al., 1991; Salgo et al., 1998) have shown the potential of this technology for soil analysis, estimating different parameters just with one single scan. The main advantages of NIR applications in soils are the speed of response, allowing the increase of the number of samples analysed to define a particular soil, and the instantaneous elaboration of recommendations for fertilization and soil amendment. Another advantage is to avoid the use of chemical reagents at all, being an environmentally safe technique. In this paper, we have studied a set of 129 soil samples selected from representative glasshouse soils from Southern Spain. The samples were dried, milled, and sieved to pass a 2 mm sieve and then analysed for organic carbon, total nitrogen, inorganic nitrogen (nitrate ammonium), hygroscopic humidity, pH and electrical conductivity in the 1:1 extract. NIR spectra of all samples were obtained in reflectance mode using a Foss NIR Systems 6500 spectrophotometer equipped with a spinning module. Calibration equations were developed for seven analytical parameters (ph, Total nitrogen, organic nitrogen, organic carbon, C/N ratio and Electric Conductivity). Preliminary results show good correlation coefficients and standard errors of cross validation in equations obtained for Organic Carbon, Organic Nitrogen, Total Nitrogen and C/N ratio. Calibrations for nitrates and nitrites, ammonia and electric conductivity were not acceptable. Calibration obtained for pH had an acceptable SECV, but the determination coefficient was found very poor probably due to the reduced range in reference values. Since the estimation of Organic Carbon and C/N ratio are acceptable NIIRS could be used as a fast method to assess the necessity of organic amendments in soils from Mediterranean regions where the low level of organic matter in soils constitutes an important agronomic problem. Furthermore, the possibility of a single and fast estimation of Total Nitrogen (tedious determination by modifications of the Kjeldahl procedure) could provide and interesting data to use in the estimation of nitrogen fertilizer rates by means of nitrogen balances.

• Clean Technology
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• v.15 no.3
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• pp.194-201
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• 2009

Reductive reactivity of zero-valent iron nanoparticles was investigated for removal of nitrate-nitrogen which is considered one of the major water pollutants. To elucidate the difference in reactivity between preparation methods, iron nanoparticles were synthesized respectively from microemulsion and aqueous solution of ferric ions. Iron nanoparticles prepared from microemulsion were deposited on aluminum by electrophoretic method, and their reaction kinetics was compared to that of the same nanoparticles suspended in aqueous batch reaction. With an approximation of pseudo-first-order reaction, rate constants for suspended nanoparticles prepared from microemulsion and dilute aqueous solution were $3.49{\times}10^{-2}min^{-1}$ and $1.40{\times}10^{-2}min^{-1}$, respectively. Iron nanoparticles supported on aluminum showed ca. 30% less reaction rate in comparison with the identical nanoparticles in suspended state. However, supported nanoparticles showed the superior effectiveness in terms of nitrate-nitrogen removal per zero-valent iron input especially when excess amounts of nitrates were present. Iron nanoparticles deposited on aluminum maintained reductive reactivity for more than 3 hours, and produced nitrogen gas as a final reduction product of nitrate-nitrogen.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.271-280
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• 2024

This study examines the European Union (EU)'s policies on managing nitrate contamination in groundwater and provides implications for the future groundwater management in South Korea. Initiated by the 1991 Nitrate Directive, the EU has pursued a multifaceted approach to reduce agricultural nitrate pollution through sustainable ('good') farming practices, regular nitrate level monitoring, and designating Nitrate Vulnerable Zones. Further policy integrations, like the Water Framework Directive and Groundwater Directive, have established comprehensive protection strategies, including the use of pollutant threshold values. Recently, the 2019 Green Deal escalated efforts against nitrates, aligning with broader environmental and climate objectives. This review aims to explore these developments, highlighting key mitigation strategies against nitrate pollution, and providing valuable insights for the future sustainable groundwater nitrate management in South Korea, emphasizing the importance of preventive measures and collaborative efforts to restore and improve groundwater quality.

• Journal of Veterinary Clinics
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• v.6 no.2
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• pp.227-259
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• 1989

Waterpepper is a weed which grows on damp soil. especially near swamps, and in shallow water of ponds and ditches. It Is widespread throughout the country In abundant colonies. In the present experiments, possible toxic effects of waterpepper were investigated in ruminants. Pour cows were fed waterpepper ad libitum or by force in the from of green forage, hay and/or powder, 8 goats were administered in the form of methanol extract, and 4 goats, crude juice, into the lumen. Clinical signs were examined as well as urinalysis, hematology, serum chemical analysis, pH/blood gas analysis and chclinesterase activities following administration of waterpepper. Six goats which were administered the methanol extract or crude juice were sacrificed for pathological examinations., In addition to the clini copathological examinations, the chemical constituents of waterpepper were qualitively analyzed from the methanol extract and the Effects of the waterpepper crude juice were examined on the motility of rabbit duodenum and uterus. It is revealed that waterpepper contains steroids, terpenoids, flavonoids, tannin and essential oils in the methanol extract and nitrates in the crude juice. The crude juice of waterpepper relaxed the rabbit uterine and duodenal smooth muscles. The constraction of duodenum by acetylcholine or BaCl$_2$ were partially inhibited by pretreatment of the crude juice. However, the relaxation of duodenum by the crude juice was not blocked by the pretreatments of phenoxybenzamlne, propranolol, cocaine, reserpine and tetrodotoxin. The constituents of waterpepper to evoke elaxation of duodenal smooth muscle were stable to heat. The cows administered waterpepper showed common clinical symptoms such as acrid expression, restlessness, dullness, inappetence, anorexia, severe diarrhea, mild bloat and left displacement of abomasum, while bloody feces was shown in a cow. The goats administered the mothanol extract showed common clinical signs such as acrid expression, restlessness, dullness, inappetence and soft feces, while bloody feces was shown in a goat, A goat adminstered the crude juice showde bloody feces and diarrhea. Respiratory rates and heart beats were increased along with diarrhea in the experimental cows. The erythrocyte counts and MCHC were decreased whereas PCV, MCV and neutrophils were increased in the cows administered waterpepper. In goats administered methanol extract, there were decreases in erythrocytes, PCV and hemoglobin content, and an increase in MCHC. The goats ingester with the crude juice showed negligible changes in hematologic values compared with control group which was administered the same amount of water instead of the crude juice. The contents of serum calcium, Inorganic phosphorus, magnesium, Iron, glucose, cholesterol, total protein, triglycerides and phospholipids were tended to decrease in cows. In goats serum iron, glucose, triglycerides, cholesterol, BUN and phospholipids content were decreased while the content of sodium and chloride were increased after administration of the methamol extract The goats ingested with the crude juice did not show significant changes in serum chemical analysis. Even though there were some pathological findings such as hyperemia in the small intestines and kidneys and swelling of liver parenchymal cells, the values of serum AST, ALT, LDH, alkaline phosphatase, total bilirubin and creatinine did not change significantly. While proteins, hemoglobin and blood were detected in the urine of cows, urine pH, ketone bodies, glucose, bilirubin and urobilinogen content were normal or undetected. There were no significant changes in pH/bolld gas analysis data of cows and cholinesterase activities of plasma and erythrocytes of cows and goats ingested with waterpepper or the methanol extract. It is concluded that waterpepper irritates the gatrointestinal system, causes abdominal pain, relaxes the gastrointestinal smooth muscle and dilatates blood vessels supplied to the system. The irritation and relaxation may lead to abnormal fermentation, maldigestion and malabsorption of nutrients and result in diarrhea, body feces, mild bloat and left displacement of abomasum.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.111-121
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• 2003

The objective of this study is to investigate the physical and chemical properties for environmental assessment of water system affected by acid mine drainage (AMD) from coal mining activities in the Youngwol, Jungseon and Pyungchang areas in Korea. During November 2000 to July 2002, 6 times of water samples were collected season-ally from acid mine drainage and nearby streams at 13 coal mines in the study area. The physical and chemical properties including pH, Eh, TDS, salinity, bicarbonates and DO were measured in the field. Eighteen cations includ-ing Al, Ca, Fe, Mg, Mn and Zn, and 6 anions including nitrates and sulfates were also analyzed by ICP-AES and If, respectively. Acid water from the Jungam coal mine has typical characteristics of AMD with very low pH(3∼4) and high TDS(1,000∼5,000 mg/1). Relatively high concentrations(mg/kg) of heavy meals, especially for Al(380), Fe(80), Mn(44) and Zn(8), were found in water samples from the Jungam coal mine area. Water samples from the Seojin, Sebang and Sungjin coal mines also contained over 50 mg/l of Al, >100 mg/1 of Fe and )10 mg/1 of Mn. In addition to anioins, over 1,000 mg/l of sulfate was found in several water samples. Seasonally, the concentrations of metals and sulfates varied; wet season samples were relatively higher in metals and sulfates than dry season samples. It is needed to establish the proper remediation and environmental monitoring of the AMD continuously.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.382-386
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• 2011

Microbial fuel cells (MFC), devices that use bacteria as a catalyst to generate electricity, can utilize a variety of organic wastes as electron donors. The current generated may differ depending on the organic matter concentrations used, when other conditions, such as oxidant supply, proton transfer, internal resistance and so on, are not limiting factors. In these studies, a single-cathode type MFC (SCMFC) and dual-cathode type MFC (DCMFC) were used to ascertain the current's improvement through an increase in the contact area between the anode and the cathode compartments, because the cathode reaction is one of the most serious limiting factors in an MFC. Also an MFC was conducted to explore whether an improvement in electricity generation resulted from oxidizing the carbon sources and nitrates. About 250 mg $L^{-1}$ sodium acetate was fed to an anode compartment with a flow rate of 0.326 mL $min^{-1}$ by continuous mode. The current generated from the DCMFC was higher than the value produced from MFC with a single cathode. COD removal of dual-cathode MFC was also higher than that of single-cathode MFC. The nitrate didn't affect current generation at 2 mM, but when 4 and 8 mM nitrate was supplied, the current in the single-cathode and dual-cathode MFC was decreased by 98% from $5.97{\pm}0.13$ to $0.23{\pm}0.03$ mA and $8.40{\pm}0.23$ to $0.20{\pm}0.01$ mA, respectively. These results demonstrate that increasing of contact area of the anode and cathode can raise current generation by an improvement in the cathode reaction.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.E
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• pp.311-324
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• 1994

The quantitative knowledge of N $O_{\gamma}$ (＝N $O_{x}$ ＋HN $O_3$＋/PAN＋N $O_3$ ＋$N_2$ $O_{5}$ ＋HN $O_2$＋N $O_3$$^{-10}$ ＋organic nitrates＋......)distribution is essential in tropospheric chemistry, especially, especially that related to understanding the processes leading to ozone production. Ambient concentrations of NO, N $O_2$, HN $O_3$ and PAN as well as total N $O_{\gamma}$ were measured during June and early July 1992 at a rural site(Candor, NC), in the central Piedmont region of NC. The measurements of N $O_{\gamma}$ species were made in an effort to provide a comprehensive understanding of nitrogen chemistry and to investigate the total nitrogen budget at the site. N $O_{\gamma}$, N $O_2$, and NO showed diurnal variations with maxima in the morning. The maximum N $O_{\gamma}$ concentration reached was 14.5 ppbv, and the maximum concentrations of NO and N $O_2$ were 5.4 and 7.8 PPbv, respectively. The mean N $O_{\gamma}$ concentration as found to be 2.88$\pm$1.58 ppbv(n=743). The mean concentrations of NO and N $O_2$, were found to be 0.15 $\pm$ 0.29 ppbv(n＝785) and 1.31 $\pm$ 0.99 ppbv(n＝769). Products of photochemical oxidants, (N <$O_{\gamma}$-N $O_{x}$ ), such as HN $O_3$ and PAN, as well as ozone showed diurnal variation with maxima in the afternoon and minima at night The fractions of individual reactive nitrogen species to total N $O_{\gamma}$ were investigated and contrasted to the results from remote marine site and rural continental sites. N $O_{x}$ was the major species to total N $O_{\gamma}$(45%). NO concentrations appeared to be nearly constant whether the Prevailing winds were from continental areas or from oceanic areas. Linear regression of $O_3$ with (N $O_{\gamma}$- N $O_{x}$ )/N $O_{\gamma}$ (i.e. percent N $O_{x}$ converted to the photochemical products of N $O_{\gamma}$) yielded ( $O_3$) ＝25.8 〔 N $O_{\gamma}$-N $O_{x}$ 〕/(N $O_{\gamma}$) ＋27, ( $r^{2}$＝0.58). The regression intercept is interpreted as the ozone back ground (intercept=27ppbv) and the slope suggests that 8.6 molecules of ozone are formed per molecule of N $O_{x}$ oxidized products (when the average N $O_{\gamma}$ concentration, about 3 ppbv at the site, is used). The N $O_{x}$ N $O_{\gamma}$ ratio was used as an indicator of the chemical age of airmasses and the ratio showed strong positive correlations with HN $O_3$( $r^{2}$=0.58), PAN ( $r^{2}$=0.46) and $O_3$( $r^{2}$=0.62). Larger N $O_{\gamma}$ and N $O_{x}$ N $O_{\gamma}$ ratio were found when winds came from continental sides. It may suggest that synoptic meteorological conditions and transport of N $O_{x}$ are important in the distribution of N $O_{\gamma}$ and its relationship with photochemical oxidants at the site.