• 한국조리학회지
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• 제4권
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• pp.249-269
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• 1998

What satisfies the desire of human beings about taste most easily is sweet taste, and it has seemed that the pronoun of sweet taste is sugar. Sugar is used in confectionery and bread-making essentially, and it has influence on the structure and touch of baked confectionery. In addition, if we soften the and apply heat, coloring is made. Thus, it colors good. It doesn't have a sweet taste, but it has the effect to emit fragrance variously, balance and soften the product. The kinds of sugar are very diverse, and it is sugar to be referred to as white sugar is used most frequently. In this study, this researcher examined the classification of physicochemical property and melting point etc. of sugar in confectionery and bread-making through theoretical study, about the simple classification of sugar. In addition, this researcher approached about the role of sugar in confectionery and bread-making and about the influence to have when it is more or less than proper quantity, centering around function. As the result, this researcher extracted the importance of sugar in confectionery and bread-making. It means that the increase of 5% of sugar quantity decreases the absorption quantity of moisture by 1% in bread-making and that the excess of 8% of sugar slow the action of yeast in straight method. Besides, there are the properties such as absorptive property, permeability, storage nature, aging prevention of starch, oxidation restraint of oils and fats, the gelation action of pectin, the fermentation acceleration of yeast, and the emulsification-maintaining-nautre and antiseptics effect of fat-soluble material. And in confectionery, sugar makes fragrance and peel color, increases the storage nature with moisture maintenance and has the softening effect. So, it is considered that the attitude to study and make efforts continuously on the basis of the role of sugar will have to be unfolded in confectionery and bread-making.

• International Journal of Concrete Structures and Materials
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• 제11권2호
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• pp.199-213
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• 2017

Chloride penetration is among the main causes of corrosion initiation in reinforced concrete (RC) structures producing premature degradations. Weather and exposure conditions directly affect chloride ingress mechanisms and therefore the operational service life and safety of RC structures. Consequently, comprehensive chloride ingress models are useful tools to estimate corrosion initiation risks and minimize maintenance costs for RC structures placed under chloride-contaminated environments. This paper first presents a coupled thermo-hydro-chemical model for predicting chloride penetration into concrete that accounts for realistic weather conditions. This complete numerical model takes into account multiple factors affecting chloride ingress such as diffusion, convection, chloride binding, ionic interaction, and concrete aging. Since the complete model could be computationally expensive for long-term assessment, this study also proposes model simplifications in order to reduce the computational cost. Long-term chloride assessments of complete and reduced models are compared for three locations in France (Brest, Strasbourg and Nice) characterized by different weather and exposure conditions (tidal zone, de-icing salts and salt spray). The comparative study indicates that the reduced model is computationally efficient and accurate for long-term chloride ingress modeling in comparison to the complete one. Given that long-term assessment requires larger climate databases, this research also studies how climate models may affect chloride ingress assessment. The results indicate that the selection of climate models as well as the considered training periods introduce significant errors for mid- and long- term chloride ingress assessment.

• Journal of Ginseng Research
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• 제36권1호
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• pp.78-85
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• 2012

Endothelial progenitor cells (EPC) are a population of cells that circulate in the blood stream. They play a role in angiogenesis and, therefore, can be prognostic markers of vascular repair. Ginsenoside $Rg_3$ prevents endothelial cell apoptosis through the inhibition of the mitochondrial caspase pathway. It also affects estrogen activity, which reduces EPC senescence. Sun ginseng (SG), which is heat-processed ginseng, has a high content of ginsenosides. The purpose of this study was to investigate the protective effects of SG on senescence-associated apoptosis in EPCs. In order to isolate EPCs, mononuclear cells of human blood buffy coats were cultured and characterized by their uptake of acetylated low-density lipoprotein (acLDL) and their binding of Ulex europaeus agglutinin I (ulex-lectin). Flow cytometry with annexin-V staining was performed in order to assess early and late apoptosis. Senescence was determined by ${\beta}$-galactosidase (${\beta}$-gal) staining. Staining with 4'-6-Diamidino-2-phenylindole verified that most adherent cells (93${\pm}$2.7%) were acLDL-positive and ulex-lectin-positive. The percentage of ${\beta}$-gal-positive EPCs was decreased from 93.8${\pm}$2.0% to 62.5${\pm}$3.6% by SG treatment. A fluorescence-activated cell sorter (FACS) analysis showed that 4.9% of EPCs were late apoptotic in controls. Sun ginseng decreased the apoptotic cell population by 39% in the late stage of apoptosis from control baseline levels. In conclusion, these results show antisenescent and antiapoptotic effects of SG in human-derived EPCs, indicating that SG can enhance EPC-mediated repair mechanisms.

• 조명전기설비학회논문지
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• 제17권3호
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• pp.73-79
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• 2003

본 논문에서는 금속증착 커패시터 소체내에서 발생하는 셀프힐링 특성을 연구 검토하였다. 커패시터에 정격전압 이상의 직류 전압으로 셀프힐링을 발생시켜 발생위치를 표정하였으며, 발생부위에 대해서는 전자주사현미경, 에너지 분산형 X선 분광기, 적외선분광기, 시차주사열량계를 사용하여, 셀프힐링 전·후 표면구조, 성분분석, 화학적 구조변화, 열적특성을 분석하였다. 실험 결과, 셀프힐링 발생시의 부산물은 주로 탄소 성분이었다. 건전시료와 셀프힐링 발생시료의 적외선 스펙트럼 분석은 유사하였으나, 500(%)에서 열처리된 시료의 적외선 스펙트럼 분석은 서로 달랐다. 시차주사열량계 분석결과 금속증착 폴리프로필렌필름의 건전시료와 셀프칠링 발생시료의 열량 피크는 서로 달랐다.

• Journal of Welding and Joining
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• 제31권6호
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• pp.50-57
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• 2013

Characterization of microstructures and cryogenic mechanical properties of electro beam (EB) welds between cast and forged Inconel 718 superalloys has been investigated. Optimal EBW condition was found in the beam current range of 36~39 mA with the constant travel speed of 12 mm/s and arc voltage of 120 kV for 10 mm-thick specimens. Electron beam current lower than 25 mA caused to occur the liquation microfissuring in cast-side heat affected zone (HAZ) of EB welds. The HAZ liquation microfissure was found on the liquated grain boundaries with resolidified ${\gamma}/Laves$ and ${\gamma}/NbC$ eutectic constituents. EBW produced welds showing a fine dendritic structure with relatively discrete Laves phase due to fast cooling rate. After post weld aging treatment, blocky Laves phase and formation of ${\gamma}^{\prime}+{\gamma}^{{\prime}{\prime}}$ strengtheners were observed. Presence of primary strengthener and coarse Laves particles in PWHT weld may cause to reduce micro-plastic zone ahead of a crack, leading to a significant decrease in Charpy impact toughness at $-196^{\circ}C$. Fracture initiation and propagation induced by Charpy impact testing were discussed in terms of the dislocation structures ahead of crack arisen from the fractured Laves phase.

• 한국재료학회지
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• 제15권1호
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• pp.19-24
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• 2005

For the good combination of high-temperature strength, toughness and creep property, $9-12\%$ chromium steels are often used for gas turbine compressors, steam turbine rotors, blade and casing. In this study, the correlation of microstructural evolution and mechanical properties was investigated fur the specimens heat-treated at 600, 650 and $700^{\circ}C$ for 1000, 3000 and 5000 hrs. The microstructure of as-received specimen was tempered martensite with a high dislocation density, small sub-grains and fine secondary phase such as $M_23C_6$. Aging for long-time at high temperature caused the growth of martensite lath and the decrease of dislocation density resulting in the decrease in strength. However, the evolution of secondary phases had influence on hardness, yield strength and impact property. In the group A specimen aged at $600^{\circ}C\;and\;650^{\circ}C$, Laves phase was observed. The Laves phase caused the increase of the hardness and the decrease of the impact property. In addition, the abrupt growth of secondary phases caused decrease of the impact property in both A and B group specimens.

• Design & Manufacturing
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• 제15권1호
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• pp.26-31
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• 2021

As the aging ages, the disease also increases, and the development of AI technology and X-ray equipment used to treat patients' diseases is also progressing a lot. X-ray tube converts only 1% of electron energy into X-ray and 99% into thermal energy. Therefore, when the cooling time of the anode and the X-ray tube are frequently used in large hospitals, the amount of X-ray emission increases due to temperature rise, the image quality deteriorates due to the difference in X-ray dose, and the lifespan of the overheated X-ray tube may be shortened. Therefore, in this study, temperature rise and cooling time of 60kW, 75kW, and 90kW of X-ray tube anode input power were studied. In the X-ray Tube One shot 0.1s, the section where the temperature rises fastest is 0.03s from 0s, and it is judged that the temperature has risen by more than 50%. The section in which the temperature drop changes most rapidly at 20 seconds of cooling time for the X-ray tube is 0.1 seconds to 0.2 seconds, and it is judged that a high temperature drop of about 65% or more has occurred. After 20 seconds of cooling time from 0 seconds to 0.1 seconds of the X-ray tube, the temperature is expected to rise by more than 3.7% from the beginning. In particular, since 90kW can be damaged by thermal shock at high temperatures, it is necessary to increase the surface area of the anode or to require an efficient cooling system.

• 공업화학
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• 제33권6호
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• pp.588-593
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• 2022

MgO 입자 표면에 첨가된 P₂O₅의 가수분해, 발수성, 그리고 절연 거동에 미치는 영향을 조사하였다. MgO 표면에 첨가된 P₂O₅는 가수분해반응 억제와 발수성을 동시에 나타내기 때문에 독특한 절연거동을 나타내었다. 따라서 절연거동은 MgO의 표면수화반응에 의한 Mg(OH)₂와 OH^-전하 전달비와 친수성에 반비례하였다. 시효에 따른 MgO의 절연성은 표면수화반응, 첨가된 도펀트 종의 밴드갭, 그리고 도펀트의 친수성과 소수성에 강한 영향성과 의존성을 나타내었다. 마지막으로 친수성인 MgO의 표면수화반응을 억제하는 전기절연성을 발현하여 열전달매체 응용분야에서 큰 잠재력을 제공하는 것으로 나타났다.

• Medical Lasers
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• 제10권2호
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• pp.96-105
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• 2021

Background and Objectives Skin aging is reportedly associated with regulation in collagen and elastin synthesis. This study investigated the potential of combining light-emitting diode (LED) treatments using a 630-nm and 850-nm LED with simultaneous microcurrent application. Materials and Methods The dorsal skin of female pigs was treated with a home-use device. We examined the treatment effects using photography, thermocamera, microscopic pathology, and histological examination to determine the mechanism of action, efficacy, and safety of the procedure. A histological observation was performed using hematoxylin and eosin, Masson's trichrome, Victoria blue, and immunohistochemical staining. We also used the Sircol soluble collagen and elastin assay kit to measure the amounts of collagen and elastin in the porcine back skin tissue after 2 and 6 weeks. Results Evaluation by visual inspection and devices showed no skin damage or heat-induced injury at the treatment site. Histological staining revealed that accurate treatment of the targeted dermis layer effectively enhanced collagen and elastin deposition. Collagen type I, a protein defined by immunohistochemical staining, was overexpressed in the early stages of weeks 2 and 6. Combined therapy findings showed the superior capability of the 630-nm and 850-nm LED procedures to induce collagen; in contrast, elastin induction was more pronounced after microcurrent treatments. Conclusion The home-use LED device, comprising a combination of 630-nm and 850-nm LEDs and microcurrent, is safe and can be used as an adjunctive treatment for self-administered facial rejuvenation.

• 대한화장품학회지
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• 제49권3호
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• pp.225-230
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• 2023

본 연구에서는 모발 내부의 다공성 구조를 광학 현미경을 이용하여 모발의 손상 없이 관찰하였으며, 해당 결과를 이용하여 모발 내부 다공성을 정량적으로 표현하고자 하였다. 모발 내부 밀도 저하가 모발의 굽힘 및 인장 특성에 미치는 영향에 대한 실험을 진행하였으며, 모발 내부의 밀도 저하를 발생시키는 원인에 대하여 알아보고자 내인적 요인과 외인적 요인에 대한 실험을 실시하였다. 내인적 요인으로는 노화의 대표 증상의 하나인 흰머리의 다공성을 평가 정상 모발과 비교하였다. 외인적 요인으로는 일상생활에서 대표적으로 모발의 손상을 유발할 수 있는 요인인 계면활성제와 열에 의하여 모발 내부 밀도가 감소 하는 것을 관찰하였다. 또한, 아미노산과 모발 지질 소질을 방지할 수 있는 소재를 이용하여 모발 내부 밀도를 증가시키고 윤기를 증가시킬 수 있음을 확인하였다.