• Journal of the Microelectronics and Packaging Society
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• v.15 no.2
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• pp.37-45
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• 2008

In this study, reliabilities of Cu (60 um)/SnAg (20 um) double-bump flip chip assemblies were investigated for the flip chip interconnections on organic substrates with 100 um pitch. After multiple reflows at $250^{\circ}C\;and\;280^{\circ}C$, bump contact resistances were almost same regardless of number of reflows and reflow temperature. In the high temperature storage test, there was no bump contact resistance change at $125^{\circ}C$ up to 2000 hours. However, bump contact resistances slightly increased at $150^{\circ}C$ due to Kirkendall voids formation. In the electromigration test, Cu/SnAg double-bump flip chip assemblies showed no electromigration until about 600 hours due to reduced local current density. Finally, in the thermal cycling test, thermal cycling failure mainly occurred at Si chip/Cu column interface which was found out the highest stress concentration site in the finite element analysis. As a result, Al pad was displaced out under thermal cycling. This failure mode was caused by normal compressive strain acting Cu column bumps along perpendicular direction of a Si chip.

• Journal of Korea Foresty Energy
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• v.24 no.2
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• pp.31-36
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• 2005

Cauliflower mushroom (Sparassis crispa) is an edible mushroom that shows remarkably high contents of $1,3-{\beta}-D-glucan$ compared to other edible mushrooms. The mushroom is known to give high antitumor and immunologic activities, thus the mushroom is recently cultivated in Japan and Korea. However, cultivation methods are being kept in secret or under patents by some companies with complicated procedures. This study was conducted to solve the problem by providing a simple method for the cultivation of cauliflower mushroom. We could produce the mushroom using sawdust-based media of Larix leptolepis, Pinus densiflora and P. koraiensis with addition of barley flours and sugar. The ratio of the sawdust : barley flours : sugar used for this study was 80:20:3 in dry-weight base, and the water content was adjusted as 65%. The productivity was somewhat different among the species of sawdust media and the strains of Sparassis crispa for the cultivation, and the mushroom production reached up to 177g from 650g base(productivity : 27%). Thus, this medium is strongly recommended as a practical cultivation method for cauliflower mushroom. By the way, further study for the determination of adequate concentration of barley flour and the selection of proper strain for each sawdust species is needed.

• Composites Research
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• v.32 no.6
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• pp.335-341
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• 2019

In this study, an acrylic acid (AAc) was grafted on a polypropylene (PP) nonwoven fabric using electron beam irradiation. Electron beam grafting was carried out under various conditions to produce AAc grafted PP (PP-g-AAc) nonwoven fabric having a grafting yield of about 50% at radiation dose of 100 kGy and a monomer concentration of 60%. The physical and chemical properties of PP-g-AAc nonwoven fabric were evaluated by SEM, ATR-FTIR, thermal analysis and tensile strength. The morphology of PP and PP-g-AAc nonwoven fabric confirmed by SEM showed no significant change, and it was judged that AAc was introduced into PP nonwoven fabric from ATR-FTIR. PP-g-AAc nonwoven fabric showed an increase in tensile strength and a decrease in tensile strain compared to PP nonwoven fabric. However, since change of value is not significant, it is considered that there is no significant influence on the physical characterization. Adsorption experiments of PP-g-AAc nonwoven fabric on various ions showed selective adsorption behavior for lead ion. In conclusion, the electron beam radiation-induced PP-g-AAc nonwoven fabric is expected to be applied as an effective adsorbent for the adsorption of lead ions.

• Parasites, Hosts and Diseases
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• v.49 no.4
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• pp.427-430
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• 2011

The aim of this study was to test the susceptibility of mice to Trypanosoma evansi treated with human plasma containing different concentrations of apolipoprotein L-1 (APOL1). For this experiment, a strain of T. evansi and human plasma (plasmas 1, 2, and 3) from 3 adult males clinically healthy were used. In vivo test used 50 mice divided in 5 groups (A to E) with 10 animals in each group. Animals of groups B to E were infected, and then treated with 0.2 ml of human plasma in the following outline: negative control (A), positive control (B), treatment with plasma 1 (C), treatment with plasma 2(D), and treatment with plasma 3 (E). Mice treated with human plasma showed an increase in longevity of $40.9{\pm}0.3$ (C), $20{\pm}9.0$ (D) and $35.6{\pm}9.3$ (E) days compared to the control group (B) which was $4.3{\pm}0.5$ days. The number of surviving mice and free of the parasite (blood smear and PCR negative) at the end of the experiment was 90%, 0%, and 60% for groups C, D, and E, respectively. The quantification of APOL1 was performed due to the large difference in the treatments that differed in the source plasma. In plasmas 1, 2, and 3 was detected the concentration of 194, 99, and 115 mg/dl of APOL1, respectively. However, we believe that this difference in the treatment efficiency is related to the level of APOL1 in plasmas.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.543-547
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• 2006

In order to improve wine quality, the selection of yeast strain and of additives in the manufacture of Bokbunja (Rubus coreanus Miq.) wine was investigated. The chemical composition of the edible portions of Bokbunja fruits was 86.5% moisture, 0.2% crude protein, 0.9% crude fat, 6.6% crude fiber, 0.5% ash and $10^{\circ}Brix$ sugar, and was 2.99% fructose, 2.53% glucose and 0.07% sucrose in fruit extract. The predominant organic acids in the fruit were citric acid (14.57 mg/mL) and malic acid (2.24 mg/mL) with smaller amounts of shikimic, pyroglutamic and oxalic acid. During fermentation, citric and malic acid levels decreased, while formic and acetic acid were released. Saccharomyces cerevisiae KCCM 12224 (Sc-24) was more favorable for alcoholic fermentation of Bokbunja and the addition of 200 ppm of potassium metabisulphite to must was more efficient than other $SO_2$ sources with a higher overall acceptability score. Sc-24 increased alcohol production from 9.8 to 14.8% in a sugar concentration dependent manner $(18-28^{\circ}Brix)$. The color value of early stage Bokbunja must was improved by supplementing with Japanese apricot extract, but this did not influence the color value of Bokbunja wine after primary fermentation. The astringent taste of Bokbunja wine was reduced by removing the seed from the fruit. Sugar solution (50%, w/v) was used instead of sugar power to prevent the possibility of undissolved sugar due to insufficient mixing. This substitution did not influence sensory evaluation.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.548-553
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• 2006

The aim of this study was to produce Chungkookjang-a food produced through fermentation with Bacillus licheniformis E1-that contains an increased concentration of a bacterial biological response modifier (B-BRM). Unfortunately, sensory studies have indicated that B. licheniformis E1-fermented Chungkookjang is unacceptable for commercial use. We isolated another bacterial strain from this food product: B. subtilis S2. The optimum time and temperature for Chungkookjang fermentation with B. licheniformis E1 and B. subtilis S2 were 48 hr and $40^{\circ}C$, respectively. Sensory studies showed that Chungkookjang fermented by both B. licheniformis E1 and B. subtilis S2 was more acceptable than B. licheniformis E1 only. The amino nitrogen and crude protein content of the product were 359 mg% and 45.6% respectively. Additionally, it was confirmed that the proliferation of mouse splenic lymphocytes increased significantly, when the cells were treated with the BRM from Chungkookjang fermented using the mixture of bacterial strains in vitro. These results suggest that the enriched Chungkookjang may help patients who are medically in need of potentiation of lymphocytes proliferation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.463-474
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• 2009

Double symmetric patch repair of existing structures always causes membrane action only, however, in many cases this technique is not practical. On the other hand, the bending stiffness of the patch and the skin increases as tensile loading is increased and affects the bending deformation significantly in the case of single-sided patch repair. In this study, the p-convergent full layerwise model has been proposed to determine the stress concentration factor in the vicinity of a circular hole as well as across the thickness of plates with single-sided patch repair. In assumed displacement field, the strain-displacement relations and 3-D constitutive equations of a layer are obtained by the combination of 2-D and 3-D hierarchical shape functions. The transfinite mapping technique has been used to represent a circular boundary and Gauss-Lobatto numerical integration is implemented in order to directly obtain stresses occurred at the nodal points of each layer without other extrapolation techniques. The accuracy and simplicity of the present model are verified with comparison of the previous results in literatures using experiment and conventional 3-D finite element. Also, the bending effect has been investigated with various patch types like square, circular and annular shape.

• Korean journal of applied entomology
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• v.35 no.3
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• pp.221-227
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• 1996

Four strains of Beauveria bassiana F101, F587, F9 and FJ8, were received from Forestry Research Institute,Seoul. The strain, B. bassiana F101, was the most active in the enzymatic activity and spore production. Whenspores of B. bassiana FlOl were sprayed on the female larva of the black tipped sawfly with various concentrationsof 6 xl 0'~-10s~p ores/ml, insects started to die from 5-7 days, and were covered with mycelia andspores in 24-28 days at 25"C, while the insect did not show visible symptoms even after 50 days at 4'C. Theinsect injected with 5 pl of spore solution (3X l0'~-10s~p oreslml) died within 30-98 and 38-218 hours at25$^{\circ}$C and 4"C, respectively. About 3 days (60 hours) after the injection with a concentration of 3 x lo9 spores1ml, at the point of the insect's death, lots of proteins started to disappear '||'&'||' the hemolymph, fat body and carcaseat 25'C. Esterase activity in the tissues was gone suddenly after that time. Six days after the spray, manyprotein and esterase bands were lost in the hemolymph, but not those in the fat body and carcase. When thefungi growing in the host were exposed in the air, they put energy for spore production, while numerous longand thin mycelia branched out from the host body in the soil.e host body in the soil.

• Korean Journal of Pharmacognosy
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• v.47 no.2
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• pp.122-127
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• 2016

Methicillin-Resistant Staphylococcus aureus(MRSA) is a multidrug-resistant(MDR) strain. (+)-Usnic acid(UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against 17 different strains of the bacterium. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid(EDTA) was used. In the other hand, Sodium azide($NaN_3$) was used as inhibitors of ATPase. Against the 17 strains, the minimum inhibitory concentrations(MICs) of UA were in the range of $7.81-31.25{\mu}g/ml$. EDTA or $NaN_3$ cooperation against MRSA showed synergistic activity on cell wall. UA and in combination with EDTA and $NaN_3$ could lead to the development of new combination antibiotics against MRSA infection.

• Journal of Food Hygiene and Safety
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• v.17 no.1
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• pp.26-30
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• 2002

A bacterium isolated from contaminated white ginseng was indentified by using API kit and electron microscope. The isolate was determined as rod shaped bacterium having 0.6-1.0 ${\mu}{\textrm}{m}$ in diameter and 1.2-3.0 ${\mu}{\textrm}{m}$ in length. It had motility by flagellum. The isolate had $\beta$-galactosidase, arginine dihydrolase and omithin decarboxylase. It used citrate as sole carbon source but not produced H$_2$S. It also fermented glucose, manitol, sorbitol, rhamnose, sucrose, melibiose, arabinose and amygdalin. The isolate was identified as Enterobacter sp by the above API kit analysis and electron microscopy observation. Ginseng saponin was added to culture of Enterobacter sp. in order to investigate saponin's influence on its growth. The strain was incubated at 38$^{\circ}C$ for 3 days after addition of 0.05, 0.5, 2.0 and 4.0% (w/v) of saponin, respectively and the growth rates were investigated. The relative bacterial growth rates showed 75.0, 37.5, 7.5 and 0.5%, respectively, when compared with 100% of saponin non-added group. These results suggest that the growth of Enterobacter sp. is inhibited by saponin with the concentration dependency.