• The Korean Journal of Mycology
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• v.10 no.2
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• pp.75-83
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• 1982

As a primary study for cell growth and alcohol production of a cider yeast, Saccharomyces sp. R-11, cultural and nutritional characteristics of the strain were investigated. The results obtained were as follows: The optimum culture medium for this strain was a synthetic medium, Henneberg B, and sucrose was the best carbon source for yeast growth and alcohol production. Optimum sugar concentrations for yeast growth and alcohol production were 15% and 25%, respectively. Optimum pH and temperature of the basal medium for growth of this strain were 4.5 and $30^{\circ}C$ respectively. The yeast growth was enhanced by the addition of 100 ppm of $Mg^{2+}$, but significantly inhibited by the addition of 100 ppm of $Co^{2+}$. Lower temperature and maintenance of optimum pH for yeast growth increased the final alcohol concentration. Under optimum condition for cell growth at stationary culture, generation time and specific growth rate of the strain were 7.5 hr and 0.092 $hr^{-1}$, respectively. At 8% initial alcohol concentration, yeast growth was inhibited about 50% and this strain could not be grown at more than 12% initial alcohol. The strain could be grown at less than 125ppm $SO_2$without alcohol addition, and at less than 75 ppm $SO_2$ with 8% initial alcohol. The higher sulfur dioxide concentration of a medium, the longer lag phase in yeast growth was observed. This strain could induced alcoholic fermentation at less than 10% initial alcohol concentration with 0 and 25 ppm $SO_2$, at less than 8% initial alcohol with 50 and 75 ppm $SO_2$, and at less than 6% initial alcohol with 100 and 125 ppm $SO_2$.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.349-355
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• 2012

In this study, we configured a system which ranks hazardous chemicals to determine their management priorities based on experts' opinions and the existing CRS (chemical ranking and scoring). Aggregate exposure of food, health functional food, oriental/herbal medicine and cosmetics have been taken into account to determine management priority. In this study, 25 hazardous chemicals were selected, such as cadmium, lead, mercury, and arsenic, etc. These 25 materials were ranked according to their 1) risk (exposure or hazard) indexes, 2) exposure source-based weight, and 3) public interests, which were also formed based on the existing priority ranking system. Cadmium was scored the highest (178.5) and bisphenol A the lowest (56.8). Ten materials -- cadmium, lead, mercury, arsenic, tar, acrylamide, benzopyrene, aluminium, benzene, and PAHs -- scored higher than 100. Eight materials -- aflatoxin, manganese, phthalate, chromium, nitrate/nitrite, ethylcarbamate, formaldehyde, and copper -- recorded scores in the range from 70 to 100. Also evaluated as potential risks were 7 materials; sulfur dioxide, ochratoxin, dioxins, PCBs, fumonisin, methyl mercury, and bisphenol A, and these materials were scored above 50. Then we compared risk index and correlation coefficient of total scores to confirm the validity of the total scores; we analyzed correlation coefficient of parameter and indicator. We discovered that the total score and weight, which has incorporated public interests, were high and statistically significant. In conclusion, the result of this study contributes to strengthening risk assessment and risk management of hazardous chemicals.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.214-220
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• 1993

Browning of ascidian, Halocynthia roretzi, meat occurres very rapidly when skinned off or cut during processing and it resulted the quality loss of fresh frozen, dehydrated or fermented products. In this study, the causes of color development and prevention of browning were experimented. The browning of ascidian meat may be occurred enzymatically by a tyrosinase contained in meat and viscera which acted specifically on L-tyrosine as a substrate rather than on catechol. Activity of the enzyme in viscera was three times higher than in meat. The optimum pH and temperature on the tyrosinase activity of crude enzyme obtained from ascidian was 6.0 and $30{\sim}35^{\circ}C$, respectively. The enzyme was inactivated heating at $80^{\circ}C$ for 3 minutes or $90{\sim}100^{\circ}C$ for 1 minute and it was inhibited by $0.1{\sim}0.5mM$ solutions at ascorbic acid, sodium hydrogen sulfite, cystein, citric acid, cyanide but only sodium hydrogen sulfite treatment was effective to retard such a high content of enzyme as in case of viscera. In practical use for processing of ascidian meat browning was retarded by dipping the viscera removed ascidian meat in 0.2M citric acid for 5 minutes or $0.2\%$ sodium hydrogen sulfite solution for 1 minute resulting in sulfur dioxide residue less than 100 ppm.

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.275-290
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• 2021

Sulfur dioxide (SO2) in the atmosphere is mainly generated from anthropogenic emission sources. It forms ultra-fine particulate matter through chemical reaction and has harmful effect on both the environment and human health. In particular, ground-level SO2 concentrations are closely related to human activities. Satellite observations such as TROPOMI (TROPOspheric Monitoring Instrument)-derived column density data can provide spatially continuous monitoring of ground-level SO2 concentrations. This study aims to propose a 2-step residual corrected model to estimate ground-level SO2 concentrations through the synergistic use of satellite data and numerical model output. Random forest machine learning was adopted in the 2-step residual corrected model. The proposed model was evaluated through three cross-validations (i.e., random, spatial and temporal). The results showed that the model produced slopes of 1.14-1.25, R values of 0.55-0.65, and relative root-mean-square-error of 58-63%, which were improved by 10% for slopes and 3% for R and rRMSE when compared to the model without residual correction. The model performance by country was slightly reduced in Japan, often resulting in overestimation, where the sample size was small, and the concentration level was relatively low. The spatial and temporal distributions of SO2 produced by the model agreed with those of the in-situ measurements, especially over Yangtze River Delta in China and Seoul Metropolitan Area in South Korea, which are highly dependent on the characteristics of anthropogenic emission sources. The model proposed in this study can be used for long-term monitoring of ground-level SO2 concentrations on both the spatial and temporal domains.

• Clean Technology
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• v.28 no.2
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• pp.131-137
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• 2022

The semiconductor process currently emits various by-products and unused gases. Emissions containing pollutants are generally classified into categories such as organic, acid, alkali, thermal, and cabinet exhaust. They are discharged after treatment in an atmospheric prevention facility suitable for each exhaust type. The main components of organic exhaust are volatile organic compounds (VOC), which is a generic term for oxygen-containing hydrocarbons, sulfur-containing hydrocarbons, and volatile hydrocarbons, while the main components of alkali exhaust include ammonia and tetramethylammonium hydroxide. The purpose of this study was to determine the combustion characteristics and analyze the NO_X reduction rate by maintaining a direct combustion and temperature to process organic and alkaline exhaust gases simultaneously. Acetone, isopropyl alcohol (IPA), and propylene glycol methyl ether acetate (PGMEA) were used as VOCs and ammonia was used as an alkali exhaust material. Independent and VOC-ammonia mixture combustion tests were conducted for each material. The combustion tests for the VOCs confirmed that complete combustion occurred at an equivalence ratio of 1.4. In the ammonia combustion test, the NO_X concentration decreased at a lower equivalence ratio. In the co-combustion of VOC and ammonia, NO was dominant in the NO_X emission while NO₂ was detected at approximately 10 ppm. Overall, the concentration of nitrogen oxide decreased due to the activation of the oxidation reaction as the reaction temperature increased. On the other hand, the concentration of carbon dioxide increased. Flameless combustion with an electric heat source achieved successful combustion of VOC and ammonia. This technology is expected to have advantages in cost and compactness compared to existing organic and alkaline treatment systems applied separately.

• Conservation Science in Museum
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• v.30
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• pp.23-46
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• 2023

The Jija Chongtong Gun, owned by Seokdang Museum of Dong-A University, is a tubedstyle heavy weapon of the battlefield in the mid-Joseon Dynasty and is the second largest firearm after Cheonja Chongtong. The original surface color of the Jija Chongtong Gun was obscured by foreign substances and therefore it was judged that its condition requires the conservation treatment. For stable conservation treatment, gamma ray and X-ray non-destructive transmission surveys was conducted to determine the internal structure and conservation condition. And the component analysis on the material components and surface contaminants of Jija Chongtong Gun was conducted by utilizing the p-XRF component analysis, SEM-EDS component analysis, and XRD analysis. As a result of the gamma-ray and X-ray non-destructive transmission investigation, a large amount of air bubbles was observed inside Jija Chongtong Gun, and the part that appeared to be a chaplet by visual observation was not identified. As a result of gamma-ray and p-XRF component analysis, it was confirmed that Jija Chongtong Gun was bronze made of copper (Cu), tin (Sn), and lead (Pb) alloy. As a result of surface analysis of foreign substances using SEM-EDS, it was confirmed that the main components of white foreign substances were calcium (Ca), sulfur (S), and titanium (Ti). Titanium was presumed to be titanium dioxide (TiO₂), the main component of white correction fluid. The red foreign substance was confirmed to contain barium (Ba) as its main ingredient, and was presumed to be barium sulfate (BaSO₄), an extender pigment in paint. White and red contaminants, mainly composed of titanium and barium, are presumed to have been deposited on the surface in recent years. The yellow foreign substances were confirmed to be aluminum (Al) and silicon (Si), and were presumed to have originated from soil components. As a result of SEM-EDS and XRD component analysis, the white foreign substance was confirmed to be gypsum (CaS). Based on the results of component analysis, surface impurities were removed, stabilization treatment, and strengthening treatment were performed. During the conservation process, unknown inscriptions Woo (右), Byeong (兵), Sang (上), and Yi (二) were discovered through a portable microscope and precise 3D scanning. In addition, the carving method, depth, and width of the inscription were measured. Woo Byeong Sang is located above Happo Fortress in Changwon, and Yi can be identified as the second hill.

• Journal of Food Hygiene and Safety
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• v.31 no.5
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• pp.349-355
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• 2016

This study was performed to investigate food safety of 18,446 distribution foods in the northern Gyeongii area from 2010 to 2014 year. Food safety analysis was conducted by using Korean food code and food additives code. Fail determination about standards and specifications was 184 cases of 18,446 distribution foods, which represented about 1.00% fail rate of total cases. In the case of collected by food sanitation inspector, fail determination was 124 cases of 13,706 foods and showed about 0.90% fail rate. In the case of requested for food safety inspection, fail determination was 42 cases of 3,419 foods and showed about 1.23% fail rate. Results of fail determination by years, 61 cases (about 1.66%) detected fail among 3,683 foods in 2010 year, 37 cases (about 0.96%) detected fail among 3,863 foods in 2011 year, 44 cases (about 1.18%) detected fail among 3,721 foods in 2012 year, 25 cases (about 0.68%) detected fail among 3,669 foods in 2013 year, and 17 cases (about 0.48%) detected fail among 3,510 foods in 2014 year. In distribution of fail rate by month, september was showed the highest fail rate at 2.54% compared with other months. Fail determination by type of foods showed that 23 cases of perilla oil detected fail in 204 foods (about 11.27%), 32 cases of sesame oil detected fail in 394 foods (about 8.12%), 9 cases of pickles detected fail in 177 foods (about 5.08%), and 10 cases of red pepper powder detected fail in 283 foods (about 3.53%). For analysis of fail determination by examination items, microorganism was 28 fail cases (15.22%) and that was the highest level among examination items, linolenic acid and acid value were 27 fail cases (14.67%), iodine value was 19 fail cases (10.33%), content amount was 16 fail cases (8.70%), and sulfur dioxide was 9 fail cases (4.89%). In conclusion, the result of this study indicate that various fail determination items were detected of distribution foods on the market during the past five years and it was showed to higher hazard occurrence potential due to food. Therefore, more strict food safety control will be need for improving human health by prevent food health problem and ensure food safety.