• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1005-1010
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• 1999

To study the shortening of rigor mortis and changes in the morphological properties of gamma-irradiated pre-rigor bovine muscle (M). Sternomandibularis during post mortem, this experiment was performed with a test of shear force and the observation of the ultrastucture of raw muscle. The time elapsed until maximum shear force values was shortened by gamma irradiation, depending upon the dose. The release of rigor mortis started earlier than control (non-irradiated muscle). A shortening of the length of the Z-line and the maintenance of the sarcomere length by gamma irradiation was observed. The breakdown of the perimysium of muscle bundles was observed more in irradiated samples than in the control. In conclusion, it is considered that gamma irradiation on pre-rigor beef shortens aging-period, improves tenderness and enhances the beef quality.

• Journal of the Korean Institute of Gas
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• v.2 no.4
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• pp.42-46
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• 1998

Miniaturized specimen technology Permits mechanical behavior to be determined using a minimum volume of material. The technology is useful in case of not collecting a large amount of materials from industrial equipments. Five kinds of accelerated degradation materials were prepared by isothermal aging heat treatment at $630^{\circ}C$. Three kinds of specimens were prepared for impact testing. In order to increase plastic constraint of subsize specimen, side-groove was introduced. Results between subsize and full size impact testing were compared. Size effects correlations were developed for the impact properties of turbine rotor material. These correlations successfully predict the ductile brittle transition temperature (DBTT) of full size Charpy impact specimens based on subsize specimen data.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.155-162
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• 2004

An analytical method to predict the time dependent flexural behavior of composite girder is presented based on sectional analysis. The time dependent constitutive relation accounting for the early-age concrete properties including maturing of elastic modulus, creep and shrinkage is derived in an incremental format by the first order Taylor series expansion. The sectional analysis calculates the axial and curvature strains based on the force and moment equilibriums. The deflection curve of the girder approximated by the quadratic polynomial function is calculated by applying to the proper boundary conditions in the consecutive segments. Numerical applications are made for the 3-span double composite steel box girder which is a composite bridge girder filled with concrete at the bottom of the steel box in the negative moment region. The calculated results are compared with those by finite element analysis results. Close agreement is observed between the two approaches.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.2 s.43
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• pp.23-33
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• 2007

The growing environmental regulation governs the use of lead by RoHS, WEEE, and then. The electronic industry is moving to replace Pb-bearing solder with Pb-free solder. To use the Pb-free solder, microelectronic industry needs consequently the new reliability appraisal such as the packaging for high temperature process, various mechanical change caused by new solder, and the development of Pb-free sloder for long life of product. The evaluation of solder bar and mechanical properties of joint were performed compared with international standard, and new appraisal standard was established. The solderability and spread ability of Sn-0.7Cu solder material showed up to the standard. Shear test of solder joint using by the solder resulted that the shear strengths after thermal shock or after aging were not much lower than the shear strength of as-soldered and that they were also up to the standard.

• Journal of Korea Foundry Society
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• v.39 no.6
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• pp.103-109
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• 2019

Cu-added SKD11 was manufactured through the casting process and the effects of Cu addition with different contents (0, 1, 2 and 3 wt%) and aging treatment on microstructure, mechanical characteristics such as tensile strength and hardness, and thermal conductivity were investigated. The microstructure was analyzed by FE-SEM and XRD, the mechanical characteristics by Rockwell hardness tester and Tensile tester, and the thermal conductivity by Laser flash. As a result, SKD11 containing Cu had higher hardness than as-received SKD11. The hardness of as-cast SKD11 containing 1 wt% Cu was 42.4 HRC, whereas the hardness of asreceived SKD11 cast alloy was 19.5 HRC, indicating that the hardness was greatly improved when Cu was added. In the case of tensile strength, Cu-added SKD11 cast alloy had lower tensile strength than as-received SKD11, and the tensile strength tended to increase as Cu content increased. After heat treatment, however, tensile strength of as-received SKD11 was significantly increased, whereas in the case of Cu-added SKD11, as the Cu contents increased, the tensile strength increased less and even reduced at 3 wt% Cu. The thermal conductivity of Cu-added SKD11 cast alloy was about 13 W m^-1 K^-1, which was lower than that of the asreceived SKD11 cast alloy (28 W m^-1 K^-1). After the heat treatment, however, the thermal conductivity of as-received SKD11 was reduced, while the thermal conductivity of the SKD11 added with Cu was increased. Thermal conductivity was generally larger with less Cu content, and this tendency became more pronounced after heat treatment.

• Korean journal of food and cookery science
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• v.22 no.3 s.93
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• pp.337-345
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• 2006

The properties of various grains used for the solid-state cultivation of basidiomycetes were examined. The hydration time with cold water was 10 hours for malt soybean. The required hydration time for Job's tears, barley and wheat was 4, 6 and 12 hours, respectively, but the final moisture content ranged from 30 to 48 %, which was much less than the optimum moisture content for mycelial growth. For the mass cultivation of mycelia, the hydrated grains with cold water were placed in plastic bottles. The mycelial growth ra in e bottled grains was high in the early stage with inoculation of homogenized mycelium. The mycelium activity was maintained by adding sterilized water in the middle of the cultivation period. Jupjang underwent sensory evaluation to examine the possibility of utilizing basidiomycetes in functional foods. The grains fermented with Ganoderma lucidum was the best for Jupjang. The combination of malt soybean and Job's tears was the best for Jupjang. The acceptability of Jupjang was improved during the period of aging time.

• Computers and Concrete
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• v.19 no.5
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• pp.579-588
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• 2017

Creep and shrinkage are the main types of volume change with time in concrete. These changes cause deflection, cracking and stresses that affect durability, serviceability, long-term reliability and structural integrity of civil engineering infrastructure. Although laboratory test may be undertaken to determine the deformation properties of concrete, these are time-consuming, often expensive and generally not a practical option. Therefore, relatively simple empirically design code models are relied to predict the creep strain. This paper reviews the accuracy of creep and shrinkage predictions of reinforced concrete (RC) shear walls structures strengthened with carbon fibre reinforced polymer (CFRP) plates, which is characterized by a widthwise varying fibre volume fraction. This review is yielded by three commonly used international "code type" models. The assessed are the: CEB-FIP MC 90 model, ACI 209 model and Bazant & Baweja (B3) model. The time-dependent behavior was investigated to analyze their seismic behavior. In the numerical formulation, the adherents and the adhesives are all modelled as shear wall elements, using the mixed finite element method. Several tests were used to demonstrate the accuracy and effectiveness of the proposed method. Numerical results from the present analysis are presented to illustrate the significance of the time-dependency of the lateral displacements and eigenfrequencies modes.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.219-225
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• 2014

A Gompertz modeling, sigmoid in shape, is a widely used application for social science, natural science, engineering, and medical research to allow confident approximation and accurate analysis and has been applied to estimate an elderly population on aging of population. Due to the high toxicity of currently available drug delivery vehicles, various efforts have been made to reduce side-effects in clinical fields, but its application to preclinical and clinical studies is limited and there are some difficulties to optimize the parameters of Gompertz modeling applicable to preclinical studies. Therefore, in this study, we demonstrated the ability of sickle red blood cells loaded by hypotonic dialysis then photosensitized and light-activated ex vivo for controlled release and simultaneously optimized Gompertz function to evaluate controlled drug release properties of photosensitized sickle red blood cells to reduce pain-related treatments in cancer patients.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.26 no.1
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• pp.1-18
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• 2013

Objective: Recently the demands for the effective and safe depigmentative and anti-aging agents of the skin have increased due to the medical, pharmaceutical and cosmetic reasons. The purpose of this study is to investigate the MKG(Methanol Extract of Kaempferia galanga) and their dermal bioactivity properties related to cosmeceuticals such as depigmentation. Methods: We assessed inhibitory effects of MKG on melanin production in B16/F10 melanoma cells, on mushroom tyrosinase activity, effects of MKG on the expression tyrosinase, TRP-1, TRP-2, GSK-$3{\beta}$, CREB, MITF in B16/F10 melanoma cells without cytotoxicity range. Cell viability was measured by MTT assay and tyrosinase activity was assessed using by DOPA staining, western-blot analysis. We measured inhibition of melanin synthesis and tyrosinase activity by down-regulation of melanogenic enzyme expressions in ${\alpha}$-MSH induced melanogenesis B16/F10 melanoma cells. Results: MKG inhibited tyrosinase-activity, total melanin contents and dendrite out-growth. MKG inhibited melanogenesis by down-regulation of tyorsinase, TRP-1, TRP-2, CREB, and MITF in B16/F10 cells. The treatment with MKG at the 12.5, $25{\mu}g/ml$ level significantly inhibited the melanin synthesis induced ${\alpha}$-MSH in B16/F10 melanoma cells compared with untreated control. Conclusion: These results suggest that MKG inhibit melanin biosynthesis which is involved in hyper-pigmentation. So MKG is considered to be used as a whitening components reducing cytotoxicity.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.440-445
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• 2013

Balloon flower (Platycodon grandiflorum) is a kind of mountain herbs whose roots have restorative properties and the cultivating acreage of balloon flower has been steadily increasing in Korea. More frequent rain and high amount of rainfalls as a result of climate changes predisposed balloon flower to the outbreaks of root rot at high-density cultivation area in recent years. Root crowns were usually discolored into brown to blackish brown at first and the infected plants showed slight wilting symptom at early infection stage. Severely infected roots were entirely rotted and whole plants eventually died at late infection stage. The overall disease severities of root rot of balloon flower were quite variable according to the surveyed fields in Jeonnam, Gyeongnam and Jeju Provinces, which ranged from 0.1% to 40%. The root rot occurred more severely at the paddy or clay soils than the sandy soils and their severities were much higher at lowland than upland in the same localty. The disease increased with aging of the balloon flower. The causal fungi were identified as Fusarium solani and F. oxysporum on the basis of their mycological characteristics. The optimum temperature ranges of their mycelial growths was found to be $24^{\circ}C$. The pathogenic characters of F. solani and F. oxysporum treated by artificial wounding inoculation on healthy roots of balloon flower revealed that F. solani was more virulent than F. oxysporum. This study identified the causal agents of root rot of balloon flower as Fusarium solani and F. oxysporum, probably for the first time.