• Journal of agriculture & life science
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• v.50 no.4
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• pp.169-177
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• 2016

This study was carried out to compare microbiological and hygienic quality characteristics of the products reached expiration date among meat products distributing in markets. A total of 20 meat products(6 hams, 3 bacons and 11 sausages) were examined for analyses of pH, Aw, TBARS, VBN, total aerobic microbial counts, and meat colors. The pH values of samples were between 5.33 and 6.59. The water activity (Aw) of samples ranged 0.90-0.93. TBARS and VBN values of samples were 0.11-0.59 and 2.37~14.75, respectively. The contaminated levels of total aerobic bacteria were less than 2.80 CFU/g. In meat color, L*, a*, and b* values of samples were in the range of 56-72, 5.2-34 and 0.7-16, respectively. It is suggested that the quality difference of meat products is attributed to the different additives and manufacturing processes. Therefore, we suggest that the results of this study are not only applied for evaluation of the microbiological and hygienic safety but also served as fundamental information for re-establishing the shelf-life of meat products.

• Food Science and Preservation
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• v.30 no.1
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• pp.155-169
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• 2023

Jerusalem artichoke (JA, Helianthus tuberosus L.) has a great potential to enhance the quality of yakju due to the plentiful inulin content which is functional and indigestible carbohydrate in human. In this study, the optimal preparation conditions such as the added amount and steam treatment of JA were investigated to improve the quality of yakju. As the amount of JA added to yakju increased, alcohol production decreased, whereas fermentation was performed well when the steam-cooked JA was added to yakju. The pH and total acidity of yakju decreased and increased, respectively, when the amount of JA added to yakju increased, whereas pH and total acidity of yakju increased and decreased, respectively, when the steam-cooked JA was added to yakju. The free sugar and organic acid contents of yakju increased and decreased, respectively, when the amount of JA added to yakju increased, whereas those of yakju decreased when the steam-cooked JA was added to Yakju. Amino acid content of JA decreased as the amount of JA added to yakju increased and that of JA significantly decreased when the steam-cooked JA was added to yakju. In the sensory evaluation analysis, the addition of 10% unsteam-cooked JA to yakju was the best when considering sweetness, flavor, sourness, and overall preference of yakju supplemented with JA. Consequently, utilizing JA to yakju may contribute to the improvement of the quality of yakju.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.267-271
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• 2013

Test bed studies with highly efficient amine $CO_2$ solvent (KoSol-4) developed by KEPCO research institute were performed. For the first time in Korea, evaluation of post-combustion $CO_2$ capture technology to capture 2 ton $CO_2$/day from a slipstream of the flue gas from a coal-fired power station was performed. Also the analysis of solvent regeneration energy was conducted to suggest the reliable performance data of the KoSol-4 solvent. For this purpose, we have tested 5 campaigns changing the operating conditions of the solvent flow rate and the stripper pressure. The overall results of these campaigns showed that the $CO_2$ removal rate met the technical guideline ($CO_2$ removal rate: 90%) suggested by IEA-GHG and that the regeneration energy of the KoSol-4 showed about 3.0~3.2 GJ/$tCO_2$ which was, compared to that of the commercial solvent MEA (Monoethanolamine), about 25% reduction of regeneration energy. Based on these results, we could confirm the good performance of the KoSol-4 solvent and the $CO_2$ capture process developed by KEPCO research institute. And also it was expected that the cost of $CO_2$ avoided could be reduced drastically if the KoSol-4 is applied to the commercial scale $CO_2$ capture plant.

• Korean Journal of Ecology and Environment
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• v.44 no.3
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• pp.272-279
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• 2011

Copper cyanide is a chemical produced in large quantities with 2,500 tonnes being produced in 2006. It is mainly used for electroplating copper, particularly alkali-Cu plate and brass plating. The purpose of this study is to reassess the physicochemical properties and environmental fate of copper cyanide based on reliable data and and to conduct an ecotoxicity test according to the OECD test guidelines as an initial environmental risk assessment (need to state where this was done). Metal containing inorganic substances are not subject to degradation, biodegradation or hydrolysis. Aquatic toxicity tests of copper cyanide were conducted according to OECD test guideline 201, 202 and 203 for green algae, daphnia, and fish, respectively. The following acute toxicity test results were obtained for aquatic species: 0.089 mg $L^{-1}$ (Algae, 72 Hr-$EC_{50}$); 0.21 mg $L^{-1}$ (flea, 48 Hr-$LC_{50}$); 0.62 mg $L^{-1}$ (Fish, 96 Hr-$ErC_{50}$). The chemical possesses properties indicating a hazard for the aquatic environment (acute toxicity in fish, daphnia and algae below 1.0 mg $L^{-1}$). As a result of this study, copper cyanide has become a candidate for detailed risk assessment. Countries that produce this chemical in significant quantities are recommended to perform specific assessments.

• Analytical Science and Technology
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• v.27 no.3
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• pp.172-180
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• 2014

Fenpyrazamine which is a pyrazole fungicide class for controlling gray mold, sclerotinia rot, and Monilinia in grapevines, stone fruit trees, and vegetables has been registered in republic of Korea in 2013 and the maximum residue limits of fenpyrazamine is set to grape, peach, and mandarin as 5.0, 2.0, and 2.0 mg/kg, respectively. Very reliable and sensitive analytical method for determination of fenpyrazamine residues is required for ensuring the food safety in agricultural products. Fenpyrazamine residues in samples were extracted with acetonitrile, partitioned with dichloromethane, and then purified with silica-SPE cartridge and eluted with hexane and acetone mixture. The purified samples were determined by HPLC-UVD and confirmed with LC-MS and quantified using external standard method. Linear range of fenpyrazamine was between $0.1{\sim}5.0{\mu}g/mL$ with the correlation coefficient (r) 0.999. The average recovery ranged from 71.8 to 102.7% at the spiked level of 0.05, 0.5, and 5.0 mg/kg, while the relative standard deviation was between 0.1 and 7.3%. In addition, limit of detection and limit of quantitation were 0.01 and 0.05 mg/L, respectively. The results revealed that the developed and validated analytical method is possible for fenpyrazamine determination in agricultural product samples and will be used as an official analytical method.

• Proceedings of the Technology Innovation Conference
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• 1997.07a
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• pp.222-223
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• 1997

By analyzing the successful innovation case of potato microtuber mass production technology, a representative case of technology-push type creative innovation in an imitation oriented research culture, this paper attempts to figure out conceptual model of creative innovation that is initiated by the public laboratories in catching-up country, Stages of creative innovation can be divided into the internal R&D stage and the external commercialization stage. Success of the internal R&D stage depended on autonomy to secure creative research idea and commitment of individual researchers. Psychological pressure evoked from sportlights of mass media and commitment of sponsor increased the intensity of research efforts of the researcher Recognition of research problem and its significance was intensified by site visits of agricultural fields, and the recognized higher impacts of expected research results and knowledge creation achieved were a fundamental source of self-motivation. In the stage of commercialization stage, various legal, socio-economic, and psychological barriers were confronted. In a catching-up country lacking of experiences of creative innovation, creative innovation process can be regarded as a barrier elimination and cultural revolution process. Among the barriers, psychological refusal of farmers to corn-sized potato seeds was critical, which finally enforced to further researches to enlarge the size of potato seeds. In addition, the researcher has concentrated his research efforts in one specialized research area by getting a series of similar research project funds rather than diversification. It was lucky for him to have a chance to carry out a series of similar researches in one research area during the last 10 years. In getting research funds from government and private companies continuously in one research area, both internal and external promoters played significant roles.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.487-494
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• 2005

Nowadays a large amount of wastewater containing metal working fluids and cleaning agents is generated during the cleaning process of parts working in various industries of automobile, machine and metal, and electronics etc. In this study, aqueous or semi-aqueous cleaning wastewater contaminated with soluble or nonsoluble oils was treated using ultrafiltration system. And the membrane permeability flux and performance of oil-water separation (or COD removal efficiency) of the ultrafiltration system employing PAN as its membrane material were measured at various operating conditions with change of membrane pore sizes and soil concentrations of wastewater and examined their suitability for wastewater treatment contaminated with soluble or insoluble oil. As a result, in case of wastewater contaminated with soluble oil and aqueous or semi-aqueous cleaning agent, the membrane permeability increased rapidly even though COD removal efficiency was almost constant as 90 or 95％ as the membrane pore size increased from 10 kDa to 100 kDa. However, in case of the wastewater contaminated with nonsoluble oil and aqueous or semi-aqueous cleaning agent, as the membrane pore size increased from 10 kDa to 100 kDa and the soil concentration of wastewater increased, the membrane permeability was reduced rapidly while COD removal efficiency was almost constant. These phenomena explain that since the membrane material is hydrophilic PAN material, it blocks nonsoluble oil and reduces membrane permeability. Thus, it can be concluded that the aqueous or semi-aqueous cleaning solution contaminated with soluble oil can be treated by ultrafiltration system with the membrane of PAN material and its pore size of 100 kDa. Based on these basic experimental results, a pilot plant facility of ultrafiltration system with PAN material and 100 kDa pore size was designed, installed and operated in order to treat and recycle alkaline cleaning solution contaminated with deep drawing oil. As a result of its field application, the ultrafiltration system was able to separate aqueous cleaning solution and soluble oil effectively, and recycle them. Further more, it can increase life span of aqueous cleaning solution 12 times compared with the previous process.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.307-313
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• 2005

Electromigration behavior in the Sn96.5Ag3.0Cu0.5 solder lines was investigated and compared Sn96.5Ag3.0Cu0.5 with eutectic SnPb. Measurements were made for relevant parameters for electromigration of the solder, such as drift velocity, threshold current density, activation energy, as well as the product of diffusivity and effective charge number (DZ$\ast$). The threshold current density were measured to be $2.38{\times}10^4A/cm^2$ at $140^{\circ}C$ and the value represented the maximum current density which the SnAgCu solder can carry without electromigration damage at the stressing temperatures. The electromigration energy was measured to 0.56 eV in the temperature range of $110-160^{\circ}C$. The measured products of diffusivity and the effective charge number, DZ$\ast$ were $3.12{\times}10^{-10} cm^2/s$ at $110^{\circ}C$, $4.66{\times}10^{-10} cm^2/s$ at $125^{\circ}C$, $8.76{\times}10^{-10} cm^2/s$ at $140^{\circ}C$, $2.14{\times}10^{-9}cm^2/s$ at $160^{\circ}C$ SnPb solder existed incubation stage, while SnAgCu did not have incubation stage. It was thought that the diffusion mechanism of SnAgCu was different from that of SnPb.

• KSBB Journal
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• v.14 no.3
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• pp.309-314
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• 1999

In order to produce high concentration of sodium gluconate, optimization of the fermentation conditions, such as glucose concentration, inoculum size, dissolved oxygen concentration and glucose feeding method, was examined. When the glucose concentration was maintained in the range of 30∼50 g/L during the batch fermentation, glucose conversion yield and productivity were 92.2% and 6.0 g/L/hr, respectively. In the case of the low concentration below 30 g/L, the yield decreased by about 25%. As the inoculum size increased above 20%(w/v), lag phase was shortened but the productivity decreased. The dissolved oxygen level of 60∼70% was shown to be the threshold point for 75% of increase in the productivity of sodium gluconate. Finally, optimal glucose feeding rate was determined using various feeding methods such as exponential feeding, feeding based on the average glucose consumption rate and was determined using various feeding methods such as exponential feeding, feeding based on the average glucose consumption rate and on the oxygen uptake rate and etc. Our result shows that glucose feeding, based on the oxygen uptake rate is a very simple, efficient and robust method, especially when oxygen is consumed as a substrate for the bioconversion. Using the above glucose feeding strategy under the optimized condition, 255 g/L of sodium gluconate concentration, 12 g/L/hr of productivity and 95% of glucose conversion yield were achieved with A. niger ACM53.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.65-65
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• 2018

갈바륨 도금강판은 알루미늄의 우수한 차폐 특성과 내열성, 열 반사성을 가지며 아연의 희생방식 특성을 겸비하여 동일 부착량의 용융 아연도금 및 알루미늄 도금강판에 비해 우수한 내식성을 나타낸다고 알려져 있다. 또한 이것은 표면이 미려하고 경제성이 높아 건자재 용도로 현재까지도 세계적으로 널리 이용되고 있다. 여기서 지칭하는 바륨 도금강판(galvalume steel)은 아연과 알루미늄 도금강판의 장점을 접목하기 위해 55 Al-43.4 Zn-1.6 Si (wt.%)로 구성되어 개발된 3원계 성분의 합금도금강판이다. 한편, 최근에는 강재의 내식성을 향상시키기 위한 다양한 연구 결과에 의해 Zn-Al-Mg의 3원계 합금도금강판도 개발되어 사용되고 있다. 이것은 기존의 아연도금 강판 보다 10배 정도의 우수한 내식성을 나타내는 것으로 보고되고 있다. 특히, 이것은 도금된 평판부의 내식성은 물론 절단된 도금 단면부의 내식성도 매우 우수하다고 알려져 있다. 그러나 상기한 갈바륨 도금강판의 경우에는 도금된 표면부에 비해 단면부의 내식성이 상대적으로 취약한 것으로 알려져 있다. 따라서 본 연구에서는 갈바륨 도금강판의 내식성을 종합적으로 향상시키기 위하여 이 갈바륨 도금강판 상에 PVD 스퍼터링법에 의해 Mg 코팅막의 제작을 시도하였다. 여기서 Mg 코팅막은 후처리 된 갈바륨 도금강판 상에 Ar 공정압력 2 및 20 mTorr 조건 중 1.5 및 $3{\mu}m$ 두께로 제작하였다. 또한 제작한 코팅막에 대해서는 모폴로지 관찰(SEM) 및 결정구조 분석(XRD)을 하였고, 분극측정, 염수분무 시험(SST) 및 복합부식 시험(CCT)에 의해 표면 및 단면부의 내식성평가를 수행하였다. 또한 여기서는 염수분무 및 복합부식 시험 후의 시험편도 채취 하여 표면 및 단면부위에 대한 원소조성 분석(EPMA)과 결정구조 분석(XRD)을 실시하였다. 이상의 실험 결과에 의하면, 본 실험에서 제작한 Mg 코팅막은 그 두께가 두꺼울수록 표면 Mg 결정립의 크기가 증가하였고, 그 부식속도가 증가하는 경향을 나타내었다. 또한 여기서는 공정압력이 높은 조건에서 제작한 막일수록 Mg(002)면 피크 강도가 감소하고 Mg(101)면 피크의 배향성이 증가하였다. 그때 그 막의 내식성은 향상되는 경향을 나타내었다. 그리고 종합적으로 염수분무 및 복합부식 시험 결과에 의하면 Mg이 코팅된 갈바륨 도금강판은 기존 갈바륨 도금강판 보다 내식성이 현저히 향상되었다. 특히, 단면부 내식성의 경우에는 기존 대비 5배 이상 향상되는 경향을 나타내었다. 여기서 단면부 내식특성 분석을 위한 EPMA 원소조성 분석 결과에 의거하면, 부식 초기에는 마그네슘의 부식생성물에 의해 단면부가 치밀하게 보호되고 있음을 확인할 수 있었다. 그 이후에는 부식이 지속적으로 진행됨에 따라 갈바륨 도금층에서 용출된 알루미늄 및 아연 성분이 마그네슘과 함께 치밀한 부식생성물을 형성하여 단면부를 차폐함에 따라 단면부의 내식성이 크게 향상된 것으로 생각된다. 이러한 부식생성물의 결정구조 분석 결과에 따르면, 염수분무와 복합부식 시험에서는 공통적으로 MgO, $Mg(OH)_2$ 이외에도 Simonkolleite상 등이 형성되었다. 또한 건-습 반복 부식시험인 복합부식시험 후에는 $Mg_5(CO_3)_4(OH)_24H_2O$(Hydromagnesite)상 등이 형성됨을 확인할 수 있었다. 즉, 본 실험에서 후처리된 갈바륨 도금강판 상에 제작한 마그네슘 코팅막의 경우에는 상기와 같은 다양한 부식반응에 의해 표면 및 단면부에 형성된 Mg계 부식생성물과 $Zn_5(OH)_8Cl_2H_2O$(Simonkolleite)상에 의해서 표면은 물론 단면부 내식성이 크게 향상된 것으로 사료된다.