• Journal of Welding and Joining
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• 제14권6호
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• pp.93-100
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• 1996

Effect of a flux composition on weld metal toughness in submerged arc welding with 60kgf/$\textrm{mm}^2$ grade C-Mo type wires was investigated and interpreted in terms of weld metal microstructure and hardenability. Flux workability was also studied by characterizing a weld bead profile. Compared to other weld metals, .weld metal used alumina basic flux with nickel showed lowest oxygen content, highest hardenability and the most acicular ferrite. The highest impact toughness of that weld metal, however, was attributed to the tough matrix due to the nickel rather than to the larger amount of acicular ferrite. Manganese silicate flux had better workability than alumina basic flux, showing broader welding conditions resulting in a depth-to-width ratio of 0.5. The composition of oxides in the weld metal was dependent on the flux composition, showing MnO-SiO$_2$-TiO in manganese silicate flux and MnO-SiO$_2$-Al$_2$O$_3$-TiO in alumina basic flux. MnO-SiO$_2$composition in both oxides was similar to a tephroite.

• Journal of Welding and Joining
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• 제22권5호
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• pp.53-57
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• 2004

Friction stir weldability of AZ31B-H24, AZ61A-F and AZ91C-F Mg alloys were studied using microstructural observation and mechanical tests. The microstructure of stir zone(SZ) was coarse in AZ31B-H24 alloy whereas it was very fine both in AZ61A-F and AZ91C-F alloys. The hardness of SZ was remarkably increased by very fine recrystallized grains both in AZ61A-F and AZ91C-F alloys. On the other hand, the hardness of SZ was decreased in AZ31B-H24 due to the coarse microstructure. In SZ, AZ91C-F alloy showed very high hardness values because of dispersion hardening of $Mg_{17}$Al$_{12}$($\beta$ phase) and Al solid solution hardening. Because of more $Mg_{ 17}Al_{12}($\beta$ phase)$ intermetallic compounds, Mg alloy with high Al content showed poor mechanical properties.s.

• 대한수의사회지
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• 제32권7호
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• pp.428-441
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• 1996

국제수역사무국(Office International des Epizooties;OIE)의 제64차 국제위원회 총회가 지난 5월 20일부터 24일까지 프랑스 파리시내 12rue de Prony에 소재하고 있는 국제수역사무국 본부에서 개최된 바 있다. 한편, 동회의기간중 세계수의사회(World Veterinary Association;WVA) 제 48차 총회 및 관련 각 위원회 또한 국제수역사무국 본부에서 개최된 바 있다. 국제수역사무국은 지난 1924년도에, 국제적 협력이 필요한 가축전염병의 병인과 방제대책에 관련된 실험 또는 연구업무의 증진과, 회원국 정부 및 각국 수의관련 부서로부터 가축질병과 방역대책에 관련된 전반적인 관심사항에 대한 모든 사실과 기록을 수집하여 주의를 환기시키고, 전염병 방역규정에 관한 국제적 협정초안을 검토하고 서명 당사국 정부에 시행 감독권한을 부여하거나 조정을 목적으로, 프랑스 정부의 주도하에 창립멤버 28개국 정부의 조인을 받아 국제협약에 의하여 설치되어 금년에 창립 72주년을 맞이하였으며, 금년 5월 현재의 정식가입 회원국수는 143개국이 되었다. 본편에서는, 제1장에서 국제수역사무국에 대한 연혁과 조직 기능, 역할과 업무활동, 향후 활동 발전방향 등에 대하여 간략히 해설하고, 제2장에서는 금년 (1996년도) 제64차 총회의 의사일정과 주요 협의사항, 각 위원회별 보고사항 등을 소개하고자 하며, 마지막으로 제3장에서는 금년 총회의 기술의제와 관련하여 우리나라의 보고사항을 기록해 두고자 한다.

• 한국식생활문화학회지
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• 제28권3호
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• pp.312-319
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• 2013

This study investigated the quality of noodles containing different amounts of Lagocephalus lunaris powder (LLP). Noodles were prepared at ratios of 0, 1, 3, 5 and 7% LLP based on flour weight, after which cooking quality, mechanical texture properties, and viscosity were measured, and a sensory evaluation was performed. The gelatinization points of the composite LLP-wheat flours were shown to increase. Additionally, measurement of the viscosity at 95, viscosity at 95 after 15 minutes, and the maximum viscosity values decreased, as the LLP content increased. As increasing amounts of LLP were added, the L and a values decreased, whereas the b value increased and the color values, weight, and volume of cooked noodle increased, as did the turbidity of the soup. Finally the LLP additive increased hardness and decreased adhesiveness, cohesiveness and springiness. Sensory evaluation showed that high quality cooked noodle could be produced by inclusion of 5% LLP.

• Journal of Welding and Joining
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• 제10권1호
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• pp.12-19
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• 1992

용접능률의 향상을 위한 대입열용접법의 적용은 과도한 입열량으로 인하여 용접부의 인성이 저 하한다는 점에서 그 적용에 주의를 요한다. 본 보에서는 대입열용접시 열영향부의 인성 저하의 원인과 그 대책을 강재의 측면에서 검토하였다. 고장력강을 용접하면 입열량이 증가함에 따라 오스테나이트 결정립이 조대화되고 상부 베이나이트와 도상 마르텐사이트가 생성되어 인성이 저하한다. 그 대책으로서는 용접 열싸이클과정중 안정한 질화물, 산화물등을 모재에 미세분산시켜 오스테나이트 결정립 성장을 억제하고, 페라이트, 펄라이트 변태를 촉진시킨다. 이러한 석출물의 형성을 위해서는 주로 Ti, Ca, REM, B등의 합금원소가 이용된다. 소입성이 높은 주질고장력 강에서는 석출물의 분산에 의한 페라이트의 변태 촉진 보다는 Mn, Ni, Cr, Mo, V등의 합금원 소를 첨가하여 소입성을 높여 인성이 우수한 하부 베이나이트 조직을 형성하든가, 탄소량을 저 감시켜 도상 마르텐사이트의 생성을 억제하므로서 인성을 확보한다. 현재 국내에서 제조되고 있는 대입열용접용강중 인장강도 50kgf/mm$^{2}$급강은 기본적으로 용접부 인성이 우수한 TMCP법으로 제조되며, Ti등을 첨가하여 석출물의 효과를 이용하고 N을 억제하여 기지의 인 성을 향상시키는 등의 방법을 병용하고 있다. 인장강도 60kgf/mm$^{2}$ 급강은 조질처리에 의하여 제조되며, 50kgf/mm$^{2}$급강과 같이 Ti, B등의 첨가에 의한 석출물의 효과를 이용 하고 있다.

• Journal of Welding and Joining
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• 제14권2호
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• pp.46-56
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• 1996

HAZ impact toughness of Ti-oxide steel was investigated and compared to that of a conventional Ti-nitride steel. Toughness variations of each steel with weld peak temperatures and cooling rates were interpreted with microstructural transformation characteristics. In contrast to Ti-nitride steel showing continuous decrease in HAZ toughness with peak temperature, Ti-oxide steel showed increase in HAZ toughness above $1400^{\circ}C$ peak temperature. The HAZ microstructure of the Ti-oxide steel is characterized by the formation of intragranular ferrite plate, which was found to start from Ti-oxide particles dispersed in the matrix of the steel. Large austenite grain size above $1400^{\circ}C$ promoted intragranular ferrite plate formation in Ti-oxide steel while little intragranular ferrite plate was formed in Ti-nitride steel because of dissolution of Ti-nitrides. Ti-oxides in the Ti-oxide steel usually contain MnS and have crystal structures of TiO and/or $Ti_2O_3$.

• 한국환경생태학회지
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• 제8권2호
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• pp.135-141
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• 1995

주왕산 국립공원의 자연보존지구를 중심으로 분포하고 있는 천연림의 생육현황과 구조를 정확히 파악하고자, 이 지역에 21개의 방형구(20$\times$20m)를 설치하여 식생을 조사하였다. Cluster 분석한 결과 두 개의 집단으로 분류되었다. 수종간의 상관관계는 서어나무와 물푸레나무, 졸참나무와 굴참나무, 생강나무와 국수나무 등의 수종들 간에는 비교적 높은 정의 상관관계를, 고로쇠나무와 쇠물푸레, 당단풍과 굴참나무 둥의 수종들 간에는 높은 부의 상관관계를 보였다. 본 조사지의 종다양도는 1.1306~l.2688로 비교적 높게 나타났다.

• 한국식품영양과학회지
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• 제27권3호
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• pp.501-507
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• 1998

This study was aimed to determine the cooking properties of noodles when dfferent concentrations of Aster scaber THUNB(AST) juice were added to the buckwhenat and wheat flours. Also, physicochemical effects of the noodles and compositions of the noodles and compositions of the noodle soup after cooking were determined. Buckwheat flour and AST contained greater amounts of minerals and essential amino acids than wheat flour. The contents of chlorophyll and carotenoids in the buckwheat noodle added AST juice increased as the concentrations of AST juice increased. Hydration capacity of buckwheat flour was higher than that of wheat flour when AST juice was added to flours. The added amounts of AST juice did not affect the volume and the weight of the noodles, but those were increased as cooking time proceeded. The release of proteins and minerals from the buckwheat noodle added AST juice increased as cooking time progressed and also at the added concentrations of AST juice increased. Texture indices showed lower values as the amount of added juice increased. In sensory evaluation, the scores of color, flavor and overall acceptability of the buckwheat noodle added AST juice were higher than those of the control.

• 한국식품영양과학회지
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• 제28권5호
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• pp.963-968
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• 1999

This study was tried to evaluate possibilities for discriminating the mixture degree of wheat flour from buckwheat products. Buckwheat was milled into four grades of powder, i.e. whole grain flour (WGF), inner layer flour(ILF), middle layer flour(MLF) and outer layer flour(OLF)), and these powders were mixed with wheat flour(WF) to make mixed samples. Ash, protein and fat contents of the buckwheat flours were high in the order of OLF=WGF>MLF>ILF. On the other hand, WF showed a similar content to OLF in ash and protein, and to ILF in fats. Potassium and magnesium contents were higher in all the buckwheat powder than in the wheat flour. Flavonoid contents were higher in order of OLF>WGF=MLF> ILF, but it was not in wheat flour. Although the reliable correlation between mix ratio and components, i.e. mag nesium or ash analyzed were found, it did not seem to reflect sufficiently the expected variations of contents of original material components. Also, compositions of commercial buckwheat products were analyzed to evaluate the mixed ratio of buckwheat flour and wheat flour. The results suggest that the components analyzed in this study as putative marker were not good in determining whether or how much buckwheat products contained wheat flour.

• 한국해양공학회지
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• 제23권5호
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• pp.32-38
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• 2009

Silicon nitride samples with aligned whisker seeds were prepared with different amounts of yttria and alumina as the sintering additives. Their sintering behaviors and the microstructural developments between $1850^{\circ}C$ and $2050^{\circ}C$ were examined. The sample with larger amount of the sintering additives showed faster densification and grain growth. Even though addition of the aligned whisker seeds slightly retarded densification of silicon nitride, it improved the flexural strength and the fracture toughness. Both the flexural strength and the fracture toughness of silicon nitride with the aligned whisker seeds were increased as the amount of the sintering additives was increased.