• Food Science of Animal Resources
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• v.44 no.4
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• pp.779-789
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• 2024

The effects of irradiation on meat constituents including water, proteins, and lipids are multifaceted. Irradiation leads to the decomposition of water molecules, resulting in the formation of free radicals that can have both positive and negative effects on meat quality and storage. Although irradiation reduces the number of microorganisms and extends the shelf life of meat by damaging microbial DNA and cell membranes, it can also accelerate the oxidation of lipids and proteins, particularly sulfur-containing amino acids and unsaturated fatty acids. With regard to proteins, irradiation affects both myofibrillar and sarcoplasmic proteins. Myofibrillar proteins, such as actin and myosin, can undergo depolymerization and fragmentation, thereby altering protein solubility and structure. Sarcoplasmic proteins, including myoglobin, undergo structural changes that can alter meat color. Collagen, which is crucial for meat toughness, can undergo an increase in solubility owing to irradiation-induced degradation. The lipid content and composition are also influenced by irradiation, with unsaturated fatty acids being particularly vulnerable to oxidation. This process can lead to changes in the lipid quality and the production of off-odors. However, the effects of irradiation on lipid oxidation may vary depending on factors such as irradiation dose and packaging method. In summary, while irradiation can have beneficial effects, such as microbial reduction and shelf-life extension, it can also lead to changes in meat properties that need to be carefully managed to maintain quality and consumer acceptability.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.559-562
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• 2003

The results and discussions of surveyed case site at constructed steel pile in potential acid sulfate soil were as follows. Topography at surveyed site was local alluvial valley and that site soils was classified as BanGog and YuGye series as detailed soil surveyed results in RDA and soil texture was Clay/Clay Loam. Soils pH was neutral, which was average 7.5 but much decreased to average 4.2 after $H_2O_2$ treatment. Organic matter and sulfate ions contents were very rich. The corrosion was severe at ground water fluctuation depth. Deposits colored black were attached to steel pile surface, which because of violent reaction in treatment HCI solution, were guessed as corrosion products (FeS) reduced by sulfate reducing bacteria(SRB). Consequently, main cause was thought microbiologically induced corrosion at this site where there is ground water fluctuation occurring oxidation and reduction reactions in turn and the soil is potential acid sulfate soil.

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1099-1105
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• 1998

A series of (diamine)isopropylidenmalonatoplatinum(Ⅱ) complexes and the oxidation products, (diamine)Pt (OOC)2C=C(CH3)2(X)2, (diamine=ethylenediamine(en), 1,2-diaminopropan(dap), N-methylethylenediamine(men); X=OH, OCOCH3, OCOCF3), have been prepared, and their interaction with guanosine-5'-monophosphate (5'-GMP) have been examined by means of 1H NMR spectroscopy. The present platinum(Ⅱ) complexes have shown to interact with 5'-GMP through N7 coordination in two concecutive steps in a similar way as with cisplatin, but no interaction between the present platinum(Ⅳ) complexes and 5'-GMP was observed. However, in the presence of ascorbic acid, the platinum(Ⅳ) complexes have been found to interact with 5'-GMP with the reaction rate depending on their reduction rate.

• Restorative Dentistry and Endodontics
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• v.18 no.2
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• pp.431-445
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• 1993

The purpose of this study was to observe corrosion characteristics of six dental amalgams and was to analyse corrosion products electrochemically. After each amalgam alloy and Hg was triturated as the direction of the manufacturer by using mechanical amalgamator, the triturated mass was inserted into the cylinderical metal mold ($12{\times}10mm$) and was condensed with 160kg/$cm^2$ by using the hydrolic press. The specimen was removed from the mold and was stored at room temperature for 1 week, and was polished with amalgam polishing kit. The anodic and cathodic polarization curve was obtained by using cyclic voltammetric method with 3-electrode potentiostat in saline for each amalgam and Ag, Sn, Cu plate specimen at $37{\pm}0.5^{\circ}C$. The potential sweep range was -1.7V~0. 4V(vs SCE) in working electrode and scan rate was 50mV/s and the exposed surface area of each specimen to the electrolytic solution was $0.79cm^2$. The results were as follows. 1. In anodic-cathodic polarization curve of amalgam specimens, two anodic current rising areas and two cathodic current peaks were obtained at the low Cu amalgam(CF, CS) specimen and three anodic current rising areas and three cathodic current peaks were obtained at the high Cu amalgam (TY, DS, HV) specimen. 2. As this compared with the anodic and cathodic current peak potentials of Sn, Cu and Ag specimen, the first cathodic current peak I c was caused by the reduction of divalent tin salt, second cathodic current peak IIIc results from the reduction of quadravalent tin salt, and third cathodic current peak me results from the reduction of copper salt. 3. As reverse potential sweeping was done repeatedly, anodic current was decreased slightly in all amalgam specimens.

• Food Science of Animal Resources
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• v.32 no.3
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• pp.346-353
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• 2012

This study was carried out in order to investigate the relationship of antioxidant enzyme activity, lipid oxidation, and aroma pattern of Hanwoo (Korean cattle) beef for 8 d at $15^{\circ}C/RH$ 100% under 0% $O_2$/20% $CO_2/80%\;N_2$, 25% $O_2$/20% $CO_2/55%\;N_2$, 50% $O_2$/20% $CO_2/30%\;N_2$, and 75% $O_2$/20% $CO_2/5%\;N_2$-conditions. The reduction of $O_2$ and the induction of $CO_2$ were shown in the 25-75% $O_2$-groups during storage and total change rates of $O_2$ and $CO_2$ were followed in order: 25%>50%>75%. Catalase activity was not significantly different among all groups. During storage, glutathione peroxidase activity decreased by increasing the $O_2$ concentration and was followed at 8 d in order: 0%>25%>50%>75% (p<0.05). From 2 d of storage, TBARS content had significant (p<0.05) differences in order: 0%>25%>50%>75%. The CIE $L^*$ value was higher (p<0.05) in the 25-75% $O_2$-groups, compared with the 0% $O_2$-group. During the first time, the CIE $a^*$ value was higher (p<0.05) in order: 0%<25%<50%<75% but was lower (p<0.05) in the 25-75% $O_2$-groups from 2 d of storage than in the 0% $O_2$-group. The CIE $b^*$ value was higher (p<0.05) in the 25-75% $O_2$-groups than in the 0% $O_2$-group and had significant (p<0.05) differences at 0 and 8 d in order: 0%<25%<50%<75%. Aroma patterns with the electronic nose were clearly discriminated between the 0% $O_2$-groups and the 25-75% $O_2$-groups at 8 d of storage. Therefore, high oxygen reduced stabilities of antioxidant enzymes, lipid oxidation, and color in Hanwoo beef. Furthermore, antioxidant enzyme activities and lipid oxidation could affect aroma patterns.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.417-430
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• 2018

This study was conducted to determine the effects of NaCl concentration and cooking temperature on the color and pigment characteristics of presalted ground chicken breasts. Four treatments with different salt concentrations (0%, 1%, 2%, and 3%) were prepared and stored for 7 d prior to cooking. Each sample was cooked to four endpoint temperatures ($70^{\circ}C$, $75^{\circ}C$, $80^{\circ}C$, and $85^{\circ}C$). The salt concentration affected the color and pigment properties of the cooked ground chicken breasts. As the salt concentration increased, the cooking yield and residual nitrite content also increased. However, the samples with 1%, 2%, and 3% NaCl showed similar nitrosyl hemochrome and total pigment contents. Among the products containing salt, the samples with 3% NaCl showed the lowest percentage myoglobin denaturation (PMD) and the lowest CIE $a^*$ values. The cooking temperature had limited effects on the pigment properties of cooked ground chicken breasts. The oxidation-reduction potential and residual nitrite contents increased with cooking temperature, while the PMD, nitrosyl hemochrome, total pigment contents and CIE $a^*$ values were similar in the samples cooked at different temperatures. These results indicated that the addition of up to 2% salt to ground chicken breasts and storage for 7 d could cause the pink color defect of cooked products. However, the addition of 3% NaCl could reduce the redness of the cooked products.

• Corrosion Science and Technology
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• v.23 no.4
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• pp.315-323
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• 2024

This work examined pitting corrosion failure of a copper heat-return pipe used in a district heating system. The copper pipe was corroded with a 48% reduction in thickness due to localized corrosion on the inner surface exposed to heating water of 20 ~ 40 ℃. Fe and Si elements as corrosion products were found around pits. Cl element was also observed, which accelerated oxidation of copper inside pits. Cu₂O deposits on the pit's bottom surface decreased the pH inside the pit. X-ray diffraction analysis revealed hematite, cuprite, malachite and brochantite as corrosion products. Chemical analysis demonstrated that Fe and Si elements did not exist in the copper, supply water, or heating water, indicating that Fe and Si species might have entered into the pipe from the exterior. These results indicated that pits were initiated due to ion concentration gradient near Fe and Si species. Moreover, the interior of pits had lower pH due to Cl^- concentration and Cu₂O reactions, which accelerated the pit's growth and led to formation of pinholes. Additionally, we confirmed that the type of pitting corrosion was a complex combination of types I and II based on the HCO₃^-/SO₄^2- ratio, pH, temperature, and corrosion products.

• Applied Biological Chemistry
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• v.27
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• pp.56-67
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• 1984

As in many other country, the use of organic matter in Korea has long history. Farmers understand the value of organic matter as the source of plant nutrient and soil improving agent in general. Since 50 years ago, the sources of organic matter in paddy soils were compost, rice and barly straw, green manure, animal waste, fish and beancake, etc.. Application of green manures such as vetch and chinese milk vetch showed no significant effect on the yield of brown rice in paddy soil. On the other hand, the effects of compost and rice straw showed more significant on the yield of brown rice in paddy soil. Application of rice straw in rice cultivation is commonly made at different times between harvest, early spring and several weeks before transplanting. Considering the suitable paddy soil for application of rice straw under well to moderately well drained soil, the yield was pronounced more than poorly drained soil. Based on laboratory and field experimants, application of rice straw promoted the decrease of oxidation-reduction potential in well to moderately well drained soil. This results to be enhanced the release of some mineral nutrients,. such as potassium, calcium, silicon, and increase of availability of soil phosphorus. In the field experiments, results obtained from nitrogen fraction on the immobilization-mineralization of the tracer nitrogen applied in paddy soil,the amount and index of organic nitrogen incoporated in soil was more pronounced in rice straw application than control. Rice straw and its transformation products incoporated in the soil, provided the inflow of energy necessary to maintain heterotrophic microbes activities. Rice straw and its transformation products, especially soluble carbohydrate, enhanced the population of free-living heterotrophic $N_2$ - fixing microbes. Moreover, rice straw and its transformation products in paddy soil, enhanced the activities of soil enzymes such as dehydrogenase and urease.

• Particle and aerosol research
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• v.15 no.1
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• pp.1-13
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• 2019

Current desulfurization and denitrification technologies have reached a considerable level in terms of reduction efficiency. However, when compared with the simultaneous reduction technology, the individual reduction technologies have issues such as economic disadvantages due to the difficulty to scale-up apparatus, secondary pollution from wastewater/waste during the treatment process, requirement of large facilities for post-treatment, and increased installation costs. Therefore, it is necessary to enable practical application of simultaneous SOx and NOx treatment technologies to remove two or more contaminants in one process. The present study analyzes a technology capable of maintaining simultaneous treatment of SOx and NOx even at low temperatures due to the electrochemically generated strong oxidation of the wet-pulse complex system. This system also reduces unreacted residual gas and secondary products through the wet scrubbing process. It addresses common problems of the existing fuel gas treatment methods such as SDR, SCR, and activated carbon adsorption (i.e., low treatment efficiency, expensive maintenance cost, large installation area, and energy loss). Experiments were performed with varying variables such as pulse voltage, reaction temperature, chemicals and additives ratios, liquid/gas ratio, structure of the aeration cleaning nozzle, and gas inlet concentration. The performance of individual and complex processes using the wet-pulse discharge reaction were analyzed and compared.

• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.488-493
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• 2003

Nickel fine powders were prepared from aqueous nickel chloride solution containing organic solvents and the effect of the addition of the organic solvent on the formation of nickel powders were investigated. All products were spherical particles in the range of 0.1∼1.0 $\mu\textrm{m}$ and the agglomeration of particles did not appear. In case of containing 40 vol% of 1-propanol, the particle size reduction and homogeneity of the powders were remarkable. The average particle size and the specific surface area of the powders produced with 40 vol% of 1-propanol were 0.3 $\mu\textrm{m}$ and 16.4 m$^2$/g respectively. The reduction reaction time by hydrazine decreased with increasing of the content of 1-propanol, and was 5 min for 40 vol% of 1-propanol. The oxidation of synthesized nickel powders occurred at 320$^{\circ}C$ and weight loss at 300$^{\circ}C$ was due to dehydration of Ni(OH)$_2$.