• Korean Journal of Radiology
• /
• 제1권3호
• /
• pp.162-164
• /
• 2000

Malignant transformation of teratoma in the anterior mediastinum is rare; the mass usually has a long history and is seen in older patients. We report a case of teratoma with malignant transformation in the anterior mediastinum, complicated by rupture. CT revealed a lobulated, inhomogeneous cystic mass with a fat component and wall calcifications. The lateral wall was disrupted and consolidation in the adjacent left upper lobe was noted, suggesting rupture. A heterogeneously enhanced solid portion, obliterating the fat plane between the mass and the great vessels was present in the medial aspect of the mass, and pathologic examination demonstrated the presence of adenocarcinoma.

• 열처리공학회지
• /
• 제21권6호
• /
• pp.307-313
• /
• 2008

The tensile deformation and shape recovery behaviors were studied in Ni-Ti shape memory wires showing different transformation characteristics by annealing at $200{\sim}600^{\circ}C$. Both R phase ${\rightarrow}$ B19' martensitic transformation at lower temperature and B2 ${\rightarrow}$ R phase transformation at higher temperature occurred in the shape memory wires annealed at $200{\sim}500^{\circ}C$. Transformation temperature and heat flow of B19' martensite increase but those of R phase main almost constant even with increasing annealing temperature. In the case of wires annealed and then cooled to $20^{\circ}C$, plateau on stress-strain curves in tensile testing can be observed due to the collapse of R phase variants and the formation of deformation-induced B19' martensite. In the case of wires annealed and then cooled to $-196^{\circ}C$, however, plateau on stress-strain curves does not appear and stress increases steadily with increasing tensile deformation. Comparing shape recovery rate with cooling temperature after annealing, shape recovery rate of the wire cooled to $20^{\circ}C$ is higher than that of the wire cooled to $-196^{\circ}C$ after annealing, and maximum shape recovery rate of 95% appears in the wire annealed at $400^{\circ}C$ and then cooled to $20^{\circ}C$. $R_s$ and $R_f$ temperatures measured during shape recovery tests are higher than $A_s$ and $A_f$ temperatures measured by DSC tests even at the same annealing temperature.

• 경영정보학연구
• /
• 제5권2호
• /
• pp.1-21
• /
• 2003

e-비즈니스 환경에서 중개 유통기업은 공급자의 고객과의 직거래에 대한 위협에 대응하여 지속적인 변화를 추구하고 있다. 본 논문에서는 웹 기반 정보기술 활용을 통한 산업재 유통기업의 e-트랜스포메이션 전략을 분석적 관점에서 다루었다. 거래 비용 이론에 의하면 인터넷의 급격한 보급은 중개자와 공급자의 통합 및 아웃소싱에 의한 분할 등 상반되는 두 가지 방향을 동시에 촉진한다고 연구된 바 본 연구에서는 이러한 전략적 변화 방향에 대한 프레임웍을 중개유통 기업의 공급사슬 가치기여 이론과의 결합을 통하여 제시하였다. 공급사슬 가치기여 관점에서는 정보기술과 관련된 공급사슬 특성, 유통채널 조직간의 역학관계, 인터넷 유통 채널 특성 등의 상황적 변수가 포함되었다. 본 논문에서 제시된 프레임웍은 이와 같은 변수들의 복합적인 연계관계가 고려된 상황적 대안을 제시하고 있으며 제안된 명제들의 효과성은 산업재 유통기업의 종단적 심층 사례 연구를 통하여 분석되었다.

• 열처리공학회지
• /
• 제8권1호
• /
• pp.65-74
• /
• 1995

This research was performed to investigate the effect of ageing on grain refinement of 82wt%Cu-13.5wt%Al-4.5wt%Ni-0.1wt% misch metal alloy with ageing temperature and time. The results obtained in this study are as follows; The variation of transformation temperature with ageing temperature had very influence on ageing time at $300^{\circ}C$. But it had not influence on ageing time at $100^{\circ}C$. The variation of transformation temperature after second reversed transformation cycle was not occured in martensitic phase ageing, but $M_s$ point was appeared equally with third reversed transformation cycle in parent phase ageing. The variation of $M_s$ point was not nearly with ageing time at $100^{\circ}C$ ageing temperature. But it was decreasing with ageing time at $300^{\circ}C$ ageing temperature and $A_s$ point was increasing with ageing time. Structure of parent phase ageing was being M18R martensitic and N2H martensitic phase. It was found that ${\alpha}$ and ${\gamma}_2$ phase were created by ageing of long time at $300^{\circ}C$ ageing temperature.

• 열처리공학회지
• /
• 제6권4호
• /
• pp.213-222
• /
• 1993

This research was performed to investigate the transformation behavior and shape memory effect of Cu-13.5Al-4.5Ni(wt%) alloy with various aging temperature and time. The results obtained in this study are as follows: Transformation temperature was very increased when aging temperature is at $250^{\circ}C$. The variation of transformation temperature in first reverse transformation cycle and second was very significant, but there was little difference in case of 2nd and 3rd. Transformation temperature at various aging temperature was increased with increasing of aging temperature and time. Microvickers hardness was increased with increasing of aging temperature and time. It was found that ${\alpha}$ and ${\gamma}_2$ phase were created by aging of long time at high temperature.

• 안보군사학연구
• /
• 통권4호
• /
• pp.381-418
• /
• 2006

In present, advanced countries in the world are seen concentring on Military Transformation to create new military capability as there is a shift in Warfare Paradigm. Rapid development of technology enables military system, operational concept and organization innovated. As a result, Revolution in Military Affairs(RMA) that dramatically increased warfighting capability is pursued. Especially, advanced information technology constructs system of systems with abilities of battle visualization, information sharing in battlefield, long-range strike capability that are interoperable and combined. Corresponding to this, engagement methods and organizations are being progressively developed. The purpose of this thesis is overview of newly developing Warfare Paradigm and analysis of tendency of Military Transformation that advanced countries are pursuing preparation to this. Above all, specific aspects and contents of the Warfare Paradigm which emerged by information age were summarized. Subsequently, Military Transformation which provides the basic concepts and principles to the advanced countries in the world for the creation of new military capability was discussed. In conclusion, the tendency of Military Transformation by U.S.A, Japan, China, and Russia surround the Korean peninsular as the major power in military was carefully observed.

• 수산해양기술연구
• /
• 제27권4호
• /
• pp.321-327
• /
• 1991

Experiments of quenching were made with cylindrical specimens of carbon steel S45C of diameters from 12 to 30mm were performed. The specimens were heated by electric furnace and quenched by immersion method. In order to analyze the temperature profile(cooling curves) of carbon steel including the latent heat of phase transformation, nonlinear heat conduction problem was calculated by the numerical method of inverse heat conduction problem using the apparent heat capacity method. The difference between the calculated and the experimented cooling curves was caused by the latent heat of phase transformation, and the effects of the latent heat were especially manifest at the cooling curves of center of specimens. The temperature and the quantity of the latent heat of phase transformation depend on the cooling speed at A sub(1) transformation point, and the region for cooling speed to become zero was caused by the latent heat of phase transformation.

• Bulletin of the Korean Chemical Society
• /
• 제30권3호
• /
• pp.695-699
• /
• 2009

A short and efficient synthesis of (2S,3S)-safingol from commercially available D-ribo-(2S,3S,4R)-phytosphingosine is described. The highlights of the synthesis are a stereoselective one-pot transformation of a diol into an epoxide under phase transfer catalytic conditions and a regioselective epoxide-opening reduction with a hydride reagent.

• 대한수학회논문집
• /
• 제24권4호
• /
• pp.517-521
• /
• 2009

The object of this note is to derive Padmanabham's transformation formula for Exton's triple hypergeometric series $X_8$ by using a different method from that of Padmanabham's. An interesting special case is also pointed out.

• Plant Biotechnology Reports
• /
• 제3권4호
• /
• pp.277-283
• /
• 2009

One of the limitations to conducting maize Agrobacterium-mediated transformation using explants of immature zygotic embryos routinely is the availability of the explants. To produce immature embryos routinely and continuously requires a well-equipped greenhouse and laborious artificial pollination. To overcome this limitation, an Agrobacterium-mediated transformation system using explants of type II embryogenic calli was developed. Once the type II embryogenic calli are produced, they can be subcultured and/or proliferated conveniently. The objectives of this study were to demonstrate a stable Agrobacterium-mediated transformation of maize using explants of type II embryonic calli and to evaluate the efficiency of the protocol in order to develop herbicide-resistant maize. The type II embryogenic calli were inoculated with Agrobacterium tumefaciens strain C58C1 carrying binary vector pTF102, and then were subsequently cultured on the following media: co-cultivation medium for 1 day, delay medium for 7 days, selection medium for $4{\times}14$ days, regeneration medium, and finally on germination medium. The T-DNA of the vector carried two cassettes (Ubi promoter-EPSPs ORF-nos and 35S promoter-bar ORF-nos). The EPSPs conferred resistance to glyphosate and bar conferred resistance to phosphinothricin. The confirmation of stable transformation and the efficiency of transformation was based on the resistance to phosphinothricin indicated by the growth of putative transgenic calli on selection medium amended with $4mg\;1^{-1}$ phosphinothricin, northern blot analysis of bar gene, and leaf painting assay for detection of bar gene-based herbicide resistance. Northern blot analysis and leaf painting assay confirmed the expression of bar transgenes in the $R_1$ generation. The average transformation efficiency was 0.60%. Based on northern blot analysis and leaf painting assay, line 31 was selected as an elite line of maize resistant to herbicide.