• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.402-407
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• 2008

Recent popularity in mobile electronics requires higher standard on the mechanical strength of electronic packaging. Thus, the method of soldering between chip and substrate in electronic packaging process is changing from conventional method using intermetallic compound to a new method using organic solderability preservative (OSP) in order to improve the stability and the reliability of final product. Since current organic solder preservatives have several serious problems like thermo-stability during packaging process, however, it is necessary to develop new OSPs having thermo-stability. The main purpose of this study is to investigate the effect of MeOH/IPA (Isopropyl alcohol) ratio on the fluxing of a new OSP, developed in previous research, andto find out an optimum formulation of flux components for the application of the OSP in current packaging process. As a result of this study, it was revealed that higher MeOH/IPA ratio in flux showed better performance of fluxing a new OSP.

• Journal of Life Science
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• v.20 no.10
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• pp.1505-1510
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• 2010

In this study, we investigated antimicrobial- and anticarcinogenic activities of Amphitrite albicostatu (AA) fractions. AA was extracted with methanol first and then further fractionated into four different types: hexane (AAMH)-, methanol (AAMM)-, buthanol (AAMB)- and aqueous (AAMA) partition layers. In the paper disk test, the antimicrobial activity of AA fractions increased in proportion to concentration. Among the various solvent fractions, only AAMB showed antimicrobial activity. We also determined the growth inhibition and quinone reductase (QR) induced effects of AA fractions on cancer cells. The growth inhibition effects of AA fractions on HepG2 and B16F10 cells were evaluated by MTT assay. AAMM showed the strongest growth inhibition effects on HepG2 and B16F10 cells. The quinine reductase (QR) induced effects of AAMM on HepG2 cells at 100 ug/ml concentration indicated it to be 2.04 times higher than the control values of 1.0. Although further studies are needed, the present work suggests that Amphitrite albicostatu (AA) could have a potential use as a food preservative and chemopreventive agent.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.888-896
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• 1996

This study was conducted to investigate the preservative effects of low molecular weight chitosan with and without other preservatives on kimchi at $10^{\circ}C$ during 12 days of fermentation. The pH and titratable acidity of kimchi with preservatives (PSV) were higher and lower, respectively, than those of control kimchi (CON). The decrease in reducing sugar content was more remarkable in CON than in PSV as the fermentation proceeded. Contents of lactic acid and acetic acid were lower in PSV, especially in kimchi with chitosan dissolved in acetic acid (CH-B) and in the one containing both chitosan and Na-benzoate (CHS) than those in CON. The numbers of total viable cells, Leuconostoc sp. and Lactobacillus plantarum were higher in CON than those in PSV. Sensory firmness and green flavor were significantly lower in CON than in CH-B and CHS. Sourness and staled flavor of CH-B and CHS tended to be lower than those of other kimchi samples.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.45-50
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• 2017

We investigated effect of Zn content on shear strengh of Sn-0.7Cu-xZn and OSP surface finished solder joints. Five pastes of Sn-0.7Cu-xZn (x=0, 0.5, 1.0, 1.5, 2.0 wt.%) solders were fabricated by mixing of solder powder and flux using planatary mixer. $180{\mu}m$ diameter solder balls were formed on OSP surface finished Cu electrodes by screen print method, and the reflow process was performed. The shear strength was evaluated with two high shear speeds; 0.01 and 0.1 m/s. The thickness of the intermetallic compound(IMC) layer was decreased with increasing Zn content in Sn-0.7Cu-xZn solder. The highest shear strength was 3.47 N at the Zn content of 0.5 wt.%. As a whole, the shear strength at condition of 0.1 m/s was higher than that of 0.01 m/s because of impact stress. Fracture energies were calculated by F-x (Force-displacement) curve during high speed shear test and the tendency of fracture energy and that of shear strength were good agreement each other. Fracture took place within solder matrix at lower Zn content, and fracture occured near the interface of OSP surface finished Cu electrode and solder at higher Zn content.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.286-294
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• 1987

This experiment was carried out to investigate the bacteriolytic action of the egg white lysozyme isolated from Korean native Ogol fowl and to obtain the data for utilization of the enzyme as a food preservative. Staphyococcus aureus phage type 29 and Bacillus subtilis ATCC 6633 among the microorganisms tested were lyzed by the treatment with 0.05% lysozyme, but Staphylococcus aureus phage type 57 in addition to E. coli etc. was found to be a lysozyme- insensitive species. The lysis of S. aureus phage type 29 was maximized when incubated in nutrient broth (pH 7.0) at $37^{\circ}C$ for 24 hours and suspended it to absorbance 0.6 at 540nm in 0.05M sodium acetate but fer (pH 4.5) and then treated it with the 0.05% lysozyme for 30 min. at $30^{\circ}C$. It was found that the effect of 0.05% lysozyme in combination with 1% glycine on the growth inhibition of S. aurecus phage type 29 increased more 50% than that in the absence of glycine, but not effect with other any additeves and metal ions tested.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.490-496
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• 2005

This study was conducted to clarify the effects of chemicals and physical treatment on the split of flower stalk and the vase life of Lycoris squamigera and Lycoris radiata. There was no split of flower stalk for the Lycoris squamigera and the Lycoris radiata after the harvest of flowers and the immersion in 4 mM STA solution for 30 minutes. It was effective for the vase life of Lycoris squamigera that cut flower was pre-treated in 4 mM STS solution for 30 minutes and immersed in $5\~10\%$ sucrose + 150 ppm 8-HQS +4 ppm Rox preservative solution. The optimum periods of hot water treatments for the prevention of flower stalk split and the elongation of vase life for the cut flowers were 15 to 25 seconds for the Lycoris squamigera and 5 to 10 seconds for Lycoris radiata. Burning the cut parts of flower stalk for 10 to 30 seconds was effective for the prevention of flower stalk split and the elongation of vase life for the Lycoris squamigera, and 10 to 15 seconds for the Lycoris radiata. The vase lifes of Lycoris squamigera and Lycoris radiata were elongated when flower stalk was cut by an incline of 45 degrees compared with the horizontal cut. And Banding the flower stalks of cut flowers was effective for the prevention of flower stalk split and the elongation of vase life for the Lycoris squamigera and the Lycoris radiata.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.95-100
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• 2005

The using amount of preservative-treated wood equipments has been increased. Specially, chromate copper arsenate (CCA) has been widely used to exterior wood. We are faced to the disposal problem after service period of CCA treated wood due to its toxic heavy metals. For the disposal of end-used treated wood, land-filling and incinerating methods are mainly applied. The essential problem of incinerating is an arsenic release into atmosphere. Low pyrolysis is suggested as the methods of protecting arsenic release during incineration. The heavy metals were recovered after combustion of the treated wood at the low temperature which arsenic can not released. The recovery amounts of effectiveness compounds was determined in various solvents (citric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid) and different temperature (300, 400, $500^{\circ}C$). The higher temperature was applied, the more copper was recovered. The chromium was difficult to be recovered on the carbonized CCA treated wood at 0.5% acid concentration. The recovery mass of arsenic decreased on the higher combustion treated wood. The recovery of chromium was difficult due to the chemical change of the chromium arsenate during pyrolysis.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.804-809
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• 2015

Since Korea is home to Reticulitermes speratus, a kind of subterranean termites that prefer dark and humid conditions, there have been increasing damages to wooden structures by termites. One noticeable attribute of Korean subterranean termites is that they prefer than Pinus densiflora, the major construction material for Korean traditional houses. And because wide varieties of termites are distributed all over the world, it is not so easy to choose appropriate control methods depending on specific areas. This necessitates careful applications of the following control methods depending on the kinds of termites: fumigation treatment, soil termiticide, preservatives and insect treatment, termite colony elimination system, chemical treatment, and other physical and biological treatment methods. The purpose of this study is to investigate the control effects of environmentally-friendly Alkaline copper quaternary (ACQ), Copper Azole (CuAZ) and Micronized copper quarter (MCQ) on the termites contributing to the damage of wooden structures. It was found in this study that wood with preservative treatment produced a significantly higher termicidal efficacy than untreated wood.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.621-626
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• 2013

This study compared and analyzed the quality characteristics of five different apple juice concentrates (A~E) after alcoholic fermentation to establish test indicators for their defects. From our results, the titratable acidity was nearly similar in all diluted solutions. However, A and D showed a high pH of above 4.0 while B, C and E exhibited a low pH of below 3.0. In terms of free sugar content, maltose was undetected in A and D. In contrast, about 698 mg% maltose was found in C and more than 1,000 mg% maltose were detected in B and E. Malic acid, one of the main organic acids in apple, was measured at a high value of about 600 mg% in A and D and about 50 mg% in B, C and E. Potassium, one of the main minerals, was about 180 mg% in A and D, whereas a small amount of potassium, ranging between 6~9 mg% were present in B, C and E. Preservative (by sorbic acid) was not detected at all in all apple juice concentrates (A~E). When the above diluted apple concentrates were fermented, the alcohol contents were 11.2% and 10.8% in DAFB and AAFB, respectively. Alcoholic fermentation almost did not take place in BAFB, CAFB and EAFB. The use of maltose as the yeast may have influenced the fermentation. However, B, C and E were thought to be either defective or contaminated apple concentrates based on the analysis results of free sugar and organic acid.

• Journal of Mushroom
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• v.16 no.3
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• pp.131-139
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• 2018

The king oyster mushroom (Pleurotus eryngii) is widely consumed because of its flavor, texture, and its functional properties such as antioxidant activity and prebiotic effects. However, long-term product storage and transportation (e.g., export) are difficult because of its limited durability. The shelf-life of king oyster mushroom is affected by environmental factors such as temperature, humidity, gas composition, and ventilation, which may affect sensory characteristics including respiration rate, texture, moisture, flavor, color, and pH. The major problems regarding storage of mushrooms are browning, flavor changes, and softening. To address these problems, novel preservation techniques were developed, and more durable variants were bred. Different drying methods, gamma irradiation, chitosan coating, modified atmosphere (MA) packaging, and controlled atmosphere (CA) storage were evaluated in order to extend the shelf-life of king oyster mushrooms. Freeze drying showed better results for the preservation of mushrooms than other drying methods. Irradiation with 1 kGy was more effective for extending mushroom shelf-life than higher doses. The preservative performance of chitosan-based films was improved by combining the compound with other hydrocolloids, such as oil, protocatechuic acid, and wax. The CA storage conditions recommended for king oyster mushrooms are 5kPa $O_2$ and 10 to 15kPa $CO_2$ at temperatures below $10^{\circ}C$. Active MA packaging with microperforated PP film was also effective for maintaining quality during storage.