• Proceedings of the KWS Conference
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• 2009.11a
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• pp.12-12
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• 2009

터빈에서 핵심부품인 로터는 블레이드를 원심 운동시키는 대형 단조강이며, 고압의 증기 조건에서 고속회전하며 고온에서 운전과 저온에서 과속시험 동안 높은 원심력을 받는다. 또한 기동/정지 천이 동안 열응력을 받기 때문에, 이러한 운전조건에 부합되는 소재로서는 높은 Creep 강도 및 피로강도를 가지는 CrMoV type의 강종이 사용되어져 왔다. 발전소의 대용량화 및 고온화에 따라 종래의 증기조건에서 사용되어져 왔던 1%CrMoV강은 내산화성 및 내부식성이 문제가 되어 더 이상 사용이 불가하며, 고온/고압하에서도 우수한 소재 특성을 가지는 12%Cr강의 사용이 필수적이다. 그러나 12%Cr강으로 제작되는 로타는 Cr 양이 높기 때문에 저널부에 Galling 또는 Scuffing 이라 불리는 부적절한 마모현상과 사용 중 소착이 발생하기 쉬운 단점이 있기 때문에, 저널부에 Cr 함유량 2~3% 이하의 저합금강을 오버레이 용접하여 육성하는 일체형 가공구조의 로타 저널부가 주목되어 왔다. 따라서 본 연구에서는 Large scale 로타가 용접 도중 급열 및 급냉이 되지 않으면서 균일한 온도로 일정 시간 유지할 수 있는 열관리 장치 개발, 최적 오버레이 용접조건 선정 및 용접부 건전성 시험 평가를 통하여 12%Cr 로타 저널부의 최적 오버레이 용접공정을 확립하고자 하였다. 용접 열관리 장치는 전기저항 가열방식을 적용하고 있으며 용접이 최종 완료되기 전까지 로타 제품 전체는 $93^{\circ}C$이상의 온도로 유지 되어져야 하며, 규정 용접후열처리 온도는 $650^{\circ}C{\pm}14^{\circ}C$ 이다. 또한 로타 오버레이 용접은 모재 Set up $\Rightarrow$ 용접예열 $\Rightarrow$ GTA용접 $\Rightarrow$ SA용접 $\Rightarrow$ 용접후열(Post heating) $\Rightarrow$ 용접후열처리(PWHT) $\Rightarrow$ 정삭가공 $\Rightarrow$ NDE(UT) 순으로 수행 되어진다 실제 로타의 1/3 Scale로 시험편을 제작하여, 오버레이 mockup 시험을 수행한 후 화학성분, 경도 분포, 인장강도, 충격인성 및 굽힘시험을 수행한 결과, 오버레이 용접에서 요구되어지는 용접 물성값을 만족하는 것으로 확인되었다. 또한 균열 등의 선형 결함이나 기공, 슬라그 혼입과 같은 결함은 관찰되지 않았으며, 용접 시 아크의 안정성과 슬라그의 박리성은 양호하였으며 비드의 외관도 미려하여 용접 작업성도 양호하였다.

• Applied Biological Chemistry
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• v.12
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• pp.19-24
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• 1969

As a one of the new methods for soybean protein food processings, an attempt was made to decompose steamed soybean protein to amino acids, peptides, and other water soluble forms by the use of protease produced by Aspergillus sojae, and extract them to use as additives of low protein foods or weaning-foods of children. In this paper, as a one part of this subject, the optimum condition, such as optimum pH, temperature, digestion period, raw material's mixing ratio with wheat meal, amount of water added, and effect of sodium chloride addition, to decompose and extract soybean protein were studied. They were obtained when mixing raw materials with wheat meal in the ratio of 10:4 and adding six folds of water at $40-45^{\circ}C$, pH 5-8 for 18 hrs. digestion. Although sodium chloride addition exerted an unfavorable influence upon the decomposition of the aforementioned materials, it was effective to prolongation of digestion period. Under the abovementioned optimum conditions, the maximum extractability of soybean protein as forms of amino acids, peptides, and other water soluble forms, was nearly 70 percent against protein content of raw materials.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.3
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• pp.319-324
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• 2003

Statement of problem. Adhesives in dentistry playa major role in the success of restorative treatments. In the treatment of all ceramic restoration it is needed to find the adequate bond strength between enamel and dentin. Purpose. The purpose of this study was to evaluate shear bond strength of resin cement bonded to extracted human uncut enamel, cut enamel, and dentin in vitro. Material and methods. Ten freshly extracted anterior teeth without any previous restorative treatments were chosen. The extracted teeth were embedded in PMMA cold acrylic in the shape of a cylinder, 25 mm in diameter by 25 mm in height. The bonding system used was as follow: Uni-Etch (32% phosphoric acid), One-Step adhesive, Duolink resin cement. The specimens were acid etched and rinsed with water. Two layers of One-Step adhesive were coated with a disposable brush on the uncut enamel. VIP curing light at $500mV/cm^2$ was used to cure the adhesive. For cut enamel shear bond test, the specimen used for uncut enamel was further reduced approximately $0.3{\sim}0.5mm$ using a laminate preparation diamond bur (0.3 mm in depth). The specimens were subsequently treated with 320-grit SiC paper followed by 600-grit SiC paper and cleaned with distilled water. The bonding procedure on the cut enamel was same as uncut enamel bonding procedure. For dentin bonding test, the specimen used for cut enamel was further reduced approximately $0.5mm{\sim}1.0mm$ using a laminate preparation diamond bur (0.5 mm in depth of diamond cutting). The amount of reduction was evaluated with the silicone mold. The specimens were subsequently treated with 320-grit SiC paper followed by 600-grit silicon carbon paper and cleaned in distilled water. The bonding procedure on the dentin was same as uncut enamel bonding procedure. All samples were mounted and secured on the Ultradent shear bond test sample holder, and Ultradent restricted shear bond testing device was used with Universal Instron machine until fracture. Analysis of variance (ANOVA) test was performed comparing the result at P<0.05. Multiple comparison (Tukey) was used to compare each groups. Result. The result showed that the mean value in shear bond strength of resin cement bonded to uncut enamel, cut enamel and dentin were 27.04 Mpa, 30.25 Mpa and 26.39 Mpa with respect. Conclusion. Within the limitation of this study, the mean value of the shear bond strength of cut enamel was higher than those of uncut enamel or dentin. However there existed no statistical differences between three different human dentition substrates due to increased adhesive characteristics.

• Proceedings of the Korea Database Society Conference
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• 1998.09a
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• pp.293-312
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• 1998

$\square$ 정보화 혁명의 대국민 인식수단과 초고속정보통신망의 주요 응용 서비스로서 부각 $\square$ 전통적인 정보이용방법에 대한 이용자들의 인식의 변화로 도서관 활성화 방안으로써 정보통신기술의 도입 $\square$ 선진 각국의 전자도서관 구축의 국가적 추진 $\square$ 국내 초고속정보통신망의 구축과 보급 확대 $\square$ 모든 국민이 지역, 시간의 제약없이 도서관에 접근하여 필요한 자료를 획득 $\square$ 정보획득시간 단축으로 국내연구자들의 연구력 증진 $\square$ 정보화의 지역격차 해소 $\square$ 국내 도서관의 전자도서관 사업 촉진 $\square$ 주요 전자도서관의 통합연동체제를 마련 $\square$ 주요 도서관별 대상분야 조정으로 중복투자 방지 $\square$ 초고속정보통신망의 주요한 응용서비스로 가시화 - 초고속정보통신망의 선도적 대국민 가시화 - 이에 따른 민간부문의 참여 및 투자 촉진 $\square$ 국가, 산업, 국민생활 정보화의 주요한 기반 구축 $\square$ 지역적 정보불균형 해소 - 일부지역에 편중되어 있는 정보를 인터넷을 이용하여 시.공간 제약없이 제공함으로써 정보의 불균형 해소 $\square$ 전자도서관의 기본모델 제시 -전자도서관의 주요기능인 타기관간 자료연동 및 검색시스템을 구현함으로써 향후 구축되는 전자도서관의 기본모델 제시 $\square$ 전자도서관간 자료공유체제 구축 -시범사업 참여도서관간 분산 관리하고 있는 정보의 공유를 위한 표준체제 구축(중략) 것으로 나타났다.까지 증가율을 보여 주었다. 것으로 나타났다.대표하는 압밀계수의 추정이 가능할 것으로 사료된다. $O_3$/라는 결정학적 관계를 가지며 에피탁샬 성장했음을 알 수 있었다.있었다.다(p<0.05)..8800-0.6800로 각각 표시되었다.~$\pm$10 V의 측정범위에서 memory window가 계속 증가하는 것을 보여주었다./$^{\circ}C$의 고주파 유전특성을 얻었다. 얻었다.끼쳤다.보였다.다. 싸이클링 성능을 보였다.다.보였다.다.고 입력 반사손실을 그림 I, 2, 3에 각각 나타내었다. 대책을 요구하고 있다.하는 경향을 보였다. 생존율은 48시간째부터 폐사하기 시작하여 144시간째에는 전량폐사하였다. 삼투압 조절 능력을 위한 여러가지 파라메타에서 15 $\textperthousand$구는 이상이 없는 것으로 추측되나, 0 $\textperthousand$구에서는 코티졸, Na$^{+}$, K$^{+}$, Cl￣, 총단백질 및 AST에서 시간경과에 따른 삼투압 조절 능력에 문제가 있는 것으로 보여진다.c}C$에서 5시간 가열조리 후 잔존율은 각각 84.7% 및 73.3%였고, 질소가스 통기하에서는 잔존율이 88.9% 및 81.8%로 더욱 안정하였다.8% 및 12.44%, 201일 이상의 경우 13.17% 및 11.30%로 201일 이상의 유기의 경우에만 대조구와 삭제 구간에 유의적인(p<0.05) 차이를 나타내었다.는 담수(淡水)에서 10%o의 해수(海水)로 이주된지 14일(日) 이후에 신장(腎臟)에서 수축된 것으로 나타났다. 30%o의 해수(海水)에 적응(適應)된 틸라피아의 평균 신사구체(腎絲球體)의 면적은 담수(淡水)에 적응된 개체의 면적보다 유의성

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.411-416
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• 2002

Yogurt base was prepared from whole milk and skim milk added with 0.2∼1.0% (w/v) of Saururus chinensis(Lour.) Bail water extract (SCe) and fermented with lactic acid bacterias (the mixed strain of Streptococcas themophilus and Lactobacillus bulgaricus) at 37$\^{C}$ for 24 hr. Quality characteristics of the yogurt were evaluated in terms of acid production, number of viable cells, viscosity and sensory property during lactic acid fermentation. The composition of organic acids was also measured by HPLC. Addition of SCe stimulated the growth of lactic acid bacteria and remarkably enhanced the acid production. The viscosity and lactic acid content of yogurt were also increased by addition of SCe. The sensory score of yogurt added with 0.4% of SCe was significantly higher than other groups in taste and overall acceptability The storage abilities of yogurts added with SCe were relatively good at 5$\^{C}$ for 15 days.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.453-458
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• 2019

Synthesis of ZnCo₂O₃ oxide is performed by sol-gel method via nitrate-citrate route. Powder X-ray diffraction (XRD) study shows monoclinic unit cell having lattice parameters: a = 5.721(1) Å, b = 8.073(2) Å, c = 5.670(1) Å, β = 93.221(8)°, space group P_2/m and Z = 4. Average crystallite sizes determined by Scherrer equation are the range ~14-32 nm, whereas SEM micrographs show nano-micro meter size particles formed in ZnCo₂O₃. Endothermic peak at ~798 K in the Differential scanning calorimetric (DSC) trace without weight loss could be due to structural transformation and the endothermic peak ~1143 K with weight loss is due to reversible loss of O₂ in air atmosphere. Energy Dispersive X-ray (EDX) analysis profile shows the presence of elements Zn, Co and O which indicates the purity of the sample. Magnetic measurements in the range of +12 kOe to -12 kOe at 10 K, 77 K, 120 K and at 300 K by PPMS-II Physical Property Measurement System (PPMS) shows hysteresis loops having very low values of the coercivity and retentivity which indicates the weakly ferromagnetic nature of the oxide. Observed X-band EPR isotropic lineshapes at 300 K and 77 K show positive g-shift at g_iso ~2.230 and g_iso ~2.217, respectively which is in agreement with the presence of paramagnetic site Co²⁺(3d⁷) in the oxide. DC conductivity value of 2.875 ×10^-8 S/cm indicates very weakly semiconducting nature of ZnCo₂O₃ at 300 K. DRS absorption bands ~357 nm, ~572 nm, ~619 nm and ~654 nm are due to the d-d transitions ⁴T_1g(⁴F)→²E_g(²G), ⁴T_1g(⁴F)→⁴T_1g(⁴P), ⁴T_1g(⁴F)→⁴A_2g(⁴F), ⁴T_1g(⁴F)→⁴T_2g(⁴F), respectively in octahedral ligand field around Co²⁺ ions. Direct band gap energy, E_g~ 1.5 eV in the oxide is obtained by extrapolating the linear part of the Tauc plot to the energy axis indicates fairly strong semiconducting nature of ZnCo₂O₃.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.243-253
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• 2000

The purpose of this in vitro study was to evaluate dentin bonding by two different dentin bonding systems(DBS) using acetone based primer or adhesive [All Bond 2(AB2), One Step(OS)] when they were applied by wet or dry bonding technique. Morphology of resin-dentin interface and hybrid layer thickness(HLT) were investigated using Confocal Laser Scanning Microscope(CLSM) and compared to shear bond strength(SBS). 72 extracted sound human molars were randomly divided into 4 groups of 18 teeth each - Group 1.(AW); AB2 by wet bonding. Group 2(AD); AB2 by dry bonding. Group 3.(OW); OS by wet bonding, Group 4.(OD); OS by dry bonding. In 6 teeth of each group, notch-shaped class V cavities(depth 2mm) were prepared on buccal and lingual surface at the cementoenamel juction(12 cavities per group). To obtain color contrast in CLSM observation, bonding resins of each DBS were mixed with rhodamine B and primer of AB2 was mixed with sodium fluorescein. Prepared teeth of each group were treated with AB2, OS, respectively according to the manufacturer's instructions except for dentin surface moisture treatment after acid etching. In group 1 and 3, after acid etching, excess water was removed with wet tissue(Kimwipes), leaving consistently shiny, visibly hydrated dentin surface. In group 2 and 4, dentin surface was dried for 10 seconds at 1 inch distance. The treated teeth were then packed with composite resin(${\AE}$litefil) and light-cured. 12 microscopic samples($60{\sim}80{\mu}m$ thickness) of each group were obtained after longitudinal section and grinding(Exakt cutting and grinding system). Morphological investigation of resin-dentin interface and HLT measurement using CLSM were done. For measurement of SBS, remaining 12 teeth of each group were flattened occlusally to remove all enamel and grinded to 500 grit SiC(Pedemet Specimen Preparation Equipment). After applying DBS on the exposed dentin surface, composite resin was applied in the shape of cylinder, which has 5mm diameter, 1.5mm thickness, and light cured. SBS was measured using Instron with a crosshead speed of 0.5mm/min. It was concluded as follows, 1. HLT of AW(mean: $2.59{\mu}m$) was thicker than any other group, and followed by AD, OW, OD in descending order(mean; 2.37, 2.28, $1.92{\mu}m$). Only OD had statistically significant differences(p<0.05) to AW and AD. 2. There were intimate contact of resin and dentin at the interface in wet bonding groups, but gaps or irregular interfaces were observed in dry bonding groups. 3. The length, diameter, density of resin tags were various even in the same group without significant differences between groups and lots of adhesive lateral branches were observed. 4. There were no statistically significant difference of SBS between AB2 and OS, but SBS of wet bonding groups were significantly higher(p<0.05) than dry bonding groups. 5. There were no consistent relationships between HLT and SBS.

• The Korean Journal of Nuclear Medicine
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• v.29 no.3
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• pp.294-306
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• 1995

There has recently been increasing interest in the use of NMDA receptor antagonists as potential neuroprotective agents for the treatment of ischemic stroke. To evaluate the neuroprotective effect of the selective non-competitive NMDA receptor antagonist MK-801 in focal cerebral ischemia, local cerebral glucose utilization (ICGU) was examined in 15 neuroanatomically discrete regions of the conscious rat brain using the 2-deoxy-D[$^{14}C$] glucose quantitative autoradiographic technique 24 hr after left middle cerebral artery occlusion (MCAO). Animals received MK-801 (5 mg/kg i.v.) or saline vehicle before (20-30 min) or after (30 min) MCAO. Both pretreatment and posttreatment of MK-801 increased occluded/non-occluded ICGU ratio in 7 and 5 of the 15 regions measured, respectively (most notably in cortical structures). Following MK-801 pretreatment, there was evidence of widespread increases in ICGU not only in the non-occluded hemisphere (12 of the 15 areas studied) but also in the occluded hemisphere (13 of the 15 areas studied), while MK-801 postreatment did not significantly increase ICGU both in the normal and occluded hemispheres. These data indicate that MK-801 has a neuroprotective effect in focal cerebral ischemia and demonstrate that MK-801 provides widespread alterations of glucose utilization in conscious animals.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.402-409
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• 2002

The effects of protein-bound polysaccharides (A-PBP and L-PBP) that were extracted from the mycelia of two edible mushrooms, namely Agaricus blazai and Lentinus edodes, on serum cholesterol and body weight were investigated in mice and female volunteers. Six groups of Male Balb/c mice were fed six kinds of diet supplement- solutions composed of L-PBP, A-PBP, chitosan, and other fiber constituents, for 30 days under the normal diet. Ninety female volunteers were also supplemented for 8 weeks with six kinds of capsules including control and five test groups as the same manners (two times a day, 4 capsules). From 12 days after feeding of L-PBP (Group I) and A-PBP (Group II), the weight of mice began to reduce as compared with control, whereas that of Group III fed chitosan was decreased 15 days after feeding. Group W and Group V which were fed mixture of L-PBP, A-PBP, chitosan, and other dietary fiber, were more significant in lowering weight. After 4 weeks of the supplementation in women, their serum LDL-cholesterol level and body weights in Group I and II were reduced, but Croup 111 taken with chitosan capsule showed weaker effect than Group I and II. After 8 weeks, LDL-cholesterol content in the sera of Group I (132.5 mg/dL) and II(131.5 mg/dL) was decreased to ideal level (125.4 and 122.8 mg/dL) for healthy blood vessel. In the case of Group W supplemented with mixture of L-PBP, A-PBP, and chitosan, the weight-reduction effect (11.8%) and hypocholesterolemic effect (11.0%) was most significant, indicating their synergistic action. These data suggested that the weight-controlling and hypolipidemic effect of L-PBP and A-PBP was involved, at least in part, in absorption of cholesterol as their role of dietary fiber, as well as cholesterol metabolism.

• Food Science and Preservation
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• v.17 no.3
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• pp.405-409
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• 2010

Surface cleaning is both essential and troublesome when a consumer seeks to eliminate soil attached to the surface of fresh ginseng because all ginseng purchased in the market is covered with soil, reflecting the post-harvest situation. To facilitate ginseng use at home, a fresh-cut type of ginseng is required. As a first step toward production of such ginseng, several washing and dipping treatments were investigated with respect to surface cleaning and reduction of microbial populations on fresh ginseng. In terms of microbial distribution on the surface of fresh ginseng, higher levels of viable bacteria (6.63 log CFU/each) and fungi (5.12 log CFU/each) were present on the rhizome head than on other regions of the root. Of the washing treatments tested, hand-brushing was effective for surface cleaning and to reduce microorganism levels on fresh ginseng, but use of a high-pressure water spray followed by hand-brushing was optimally effective. To further reduce the levelsof microorganisms on the surface of fresh ginseng after washing, additional dipping treatments in 70% (v/v) ethanol and electrolyzed acidic water (at pH 2.3) were somewhat effective but showed no significant differences compared with other dipping treatments tested, including a 3 ppm ozone solution, a 200 ppm sodium hypochlorite solution, or hot water at $50^{\circ}C$.