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        검색결과 145

        62.
        2012.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Effect of Cu and powder mixing with Cu-free (Nd, Dy)-Fe-B jet-milled powder on the magnetic properties of sintered magnets was investigated. The coercivity of a magnet prepared from the Cu-free (Nd, Dy)-Fe-B powder was about 10 kOe even though the alloy powder already contained some Dy (3.5 wt%). When small copper powder was blended, however, the coercivity of the magnet increased almost 100%, exhibiting about 20 kOe. On the contrary, the coercivity enhancement was moderate, about 4 kOe, when dysprosium content in the sintered magnet was simply increased to 4.9 wt% by the addition of small 3 powder.
        4,000원
        63.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        절화용 스프레이국화 ‘오렌지엔디’는 오렌지색의 홑꽃 화형인 ‘러빈’을 방임수분하여 선발한 계통으로부터 육 성하였다. 2006년부터 4년간 촉성재배, 자연재배 및 억 제재배 작형에서 특성검정을 실시하였는데, ‘오렌지엔 디’는 오렌지색의 홑꽃 화형으로 10월 중순에 자연개 화하는 중생 추국으로 자연재배 작형에서 본당 착화수 는 19.6개, 꽃의 직경은 4.6 cm이었다. 촉성재배 작형에 서의 개화소요일수는 49일이었고, 본당 착화수는 21.1개 였다. 억제재배 작형의 개화소요일수는 50일이었다.
        4,000원
        65.
        2012.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Magnetic properties and the microstructures of magnets prepared by spark plasma sintering were investigated in order to enhance magnetic properties by grain size control. Nd-Fe-B magnets were fabricated by the spark plasma sintering under 30 MPa at various temperatures. The grain size was effectively controlled by the spark plasma sintering and it was possible to make Nd-Fe-B magnets with grain size of 5.9 .
        4,000원
        66.
        2012.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to improve the remanence of (Nd, Dy)-Fe-B sintered magnets, we investigated the influence of compaction conditions such as packing density, applied field and green density on the magnetic properties. While the remanence decreased with increasing the packing density and green density, it increased with the increase of the applied field. In addition, XRD analysis revealed that the remanence was enhanced as the degree of powder alignment was improved. The green density was more influential on the remanence than the packing density and applied field.
        4,000원
        67.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        β-phenylethyl isothiocyanate(PEITC) is a component derived from cruciferous vegetables and has been demonstrated to fight many types of cancers through various molecular pathways. In the present study, we focused on its effect on the induction of apoptotic cell death to inhibit cell growth and its molecular mechanism in HSC-4 human oral cancer cells. A colorimetric MTS assay was used to examine cell viability. The apoptotic effect and was investigated using DAPI staining and the molecular target and mechanism of PEITC-mediated apoptosis were determined by Western blotting. The result showed that PEITC inhibited oral cancer cell growth and induced apoptosis via extrinsic signaling pathway evidenced by the activation of caspase 8, truncation of bid protein and induction of death receptor(DR) 5. DR5 protein level was increased through the activation of p38 and c-Jun N-terminal kinase(JNK). These results from this study strongly suggest that DR5 is a potential molecular target for PEITC-induced apoptosis in oral cancer via p38 and JNK.
        4,000원
        68.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The HDDR(hydrogenation-disproportionation-desorption-recombination) process can be used as an effective way of converting no coercivity Nd-Fe-B material, with a coarse grain structure to a highly coercive one with a fine grain. Careful control of the HDDR process can lead to an anisotropic without any post aligning process. In this study, the effect of hydrogen gas input at various temperature in range of of hydrogenation stage (named Modified-solid HDDR, MS-HDDR) on the magnetic properties has been investigated. The powder from the modified-solid HDDR process exhibits Br of 11.7 kG and iHc of 10.7 kOe, which are superior to those of the powder prepared using the normal HDDR process.
        4,000원
        71.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. It is biphasic and is characterized by an admixture of epithelial and spindle-shaped myoepithelial cells in a variable background stroma. Epithelial-myoepithelial carcinoma (EMC) is a malignant biphasic salivary gland tumor typically composed of clear myoepithelial cells that surround epithelial-lined ducts resembling intercalated ducts. The differential diagnosis between the two tumor may be occasionally encountered because of the shared histophatologic feature. And then, it would be more reliable to differentiate the tumors based on biological behavior such as the expression of distinct intermediate filaments such as cytokeratin, invasiveness- related molecules, and the growth factor receptor to aberrantly facilitate the tumor growth, and the growth fraction of tumors. Therefore, from the 10 cases of PA and 6 cases of EMC, we immunohistochemically examined the differential expression of the cytokine 7 and 14, matrix metalloproteinase-9, C-KIT, and Ki-67 between the two tumor. At the results, there were significant differences of CK7 expression in non-luminal cells (P = 0.000) and CK14 expression in luminal and non-luminal cells of the both tumors (P = 0.025 and P = 0.000, respectively). In the comparison of the biologic behavior, a significantly increased expression of MMP-9, C-KIT and Ki-67 was found in the cases of EMC when compared to those of PA (P = 0.043, P = 0.011, and P = 0.000, respectively). In conclusion, the differences of CK expression in luminal and non-luminal cells between PA and EMC seem to reflect the difference of the origin and the level of the maturation of the tumor cell. Increased expression of MMP-9, C-KIT, and Ki-67 in EMC may represent more aggressive biologic behavior of the tumor compared with benign salivary tumor such as PA. Our results may be helpful to understand the histiogenesis of the two tumors and the difference of biologic behavior and to differentiate them when the limited specimen was submitted. Further study of many more cases of EMC is needed to validate the usefulness of these molecules as the diagnostic aid.
        4,300원
        74.
        2011.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to increase the coercivity of (Nd, Dy)-Fe-B sintered magnets without much reduction of remanence, small amount of Dy compounds such as and was mixed with (Nd, Dy)-Fe-B powder. After mixing, the coercivity of (Nd, Dy)-Fe-B sintered magnets apparently increased with the increase of Dy compound in the mixture. Addition of was more effective than for the improvement of coercivity. Reduction of the remanence by the addition of Dy compound, however, was larger than expected mostly due to unresolved coarse Dy compound in the magnet. EPMA analysis revealed that Dy was diffused throughout the grains in the magnet mixed with whereas Dy was rather concentrated around grain boundaries in the magnet mixed with .
        4,000원
        75.
        2011.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Effect of Cu content on microstructural and magnetic properties of a (wt.%), (x = 0.2, 0.3, 0.4, 0.5) strip-cast was studied. The average inter-lamellar spacing in the free surface and wheel side of the strip cast increased as the Cu content increases. The grain uniformity, the grain alignment, and (00L) texture of the strip cast increased with Cu contents up to 0.4 wt.%. These microstructural changes were attributed to the decrease of the effective cooling rate of the melted alloy caused by the decrease of the melting temperature of resulting from Cu addition. Coercivity and remanence were increased because of the grain alignment and (00L) texture improvement with Cu contents up to 0.4 wt.%.
        4,000원
        76.
        2011.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sintered Nd-Fe-B magnets are widely used in many fields such as motors, generators, actuators, microwaves and so on due to their excellent magnetic properties. Many researchers have shown that the Nd-rich phase was essentially important for high magnet properties. In this study, we focused on controlling of the Nd-rich phase to enhance magnetic properties by the cyclic sintering process. Nd-Fe-B based sintered magnets were prepared by isothermal sintering and cyclic sintering processes. Magnetic properties and microstructure of the magnets were investigated. The coercivity was enhanced from 21.2 kOe to 23.27 kOe after 10 cycles of the sintering. The Nd-rich phase was effectively penetrated into the grain boundary between the grains by the cyclic sintering.
        4,000원
        78.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In an attempt to optimize the magnetic properties of (Nd, Dy)-Fe-B sintered magnets, hydrogenation and post-sintering heat treatment processes were investigated at various hydrogenation temperatures and heat treatment temperatures. The coercivity of (Nd, Dy)-Fe-B sintered magnets hydrogenated at increased to about 1.2 kOe without any detrimental effect on the remanence. Moreover, the coercivity of the magnets was enhanced further by a consecutive and step heat treatment. These results eventually leaded to the reduction of the Dy content in a high coercive (> 30 kOe) (Nd, Dy)-Fe-B sintered magnets, as much as 10%.
        4,000원
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