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무가압 어닐드한 SiC-TiB₂ 전도성 복합체의 특성에 미치는 In Situ YAG의 영향
辛龍德(Yong-Deok Shin),朱陳榮(Jin-Young Ju),高台憲(Tae-Hun Ko) 대한전기학회 2008 전기학회논문지 Vol.57 No.5
The composites were fabricated 61[vol.%] β-SiC and 39[vol.%] TiB₂ powders with the liquid forming additives of 8, 12, 16[wt%] Al₂O₃+Y₂O₃ as a sintering aid by pressureless annealing at 1650[℃] for 4 hours. The present study investigated the influence of the content of Al₂O₃+Y₂O₃ sintering additives on the microstructure, mechanical and electrical properties of the pressureless annealed SiC-TiB₂ electroconductive ceramic composites. Reactions between SiC and transition metal TiB₂ were not observed in the microstructure and the phase analysis of the pressureless annealed SiC-TiB₂ electroconductive ceramic composites. Phase analysis of SiC-TiB₂ composites by XRD revealed mostly of α -SiC(6H), β-SiC(3C), TiB₂, and In Situ YAG(Al?Y₃O₁₂). The relative density of SiC-TiB₂ composites was lowered due to gaseous products of the result of reaction between SiC and Al₂O₃+ Y₂O₃. There is another reason which pressureless annealed temperature 1650[℃] is lower 300-450[℃] than applied pressure sintering temperature 1950-2100[℃]. The relative density, the flexural strength, the Young's modulus and the Vicker's hardness showed the highest value of 82.29[%], 189.5[Mpa], 54.60[Gpa] and 2.84[Gpa] for SiC-TiB₂ composites added with 16[wt%] Al₂O₃+Y₂O₃ additives at room temperature. Abnormal grain growth takes place during phase transformation from β-SiC into α-SiC was correlated with In Situ YAG phase by reaction between Al₂O₃ and Y₂O₃ additive during sintering. The electrical resistivity showed the lowest value of 0.0117[Ω. ㎝] for 16[wt%] Al₂O₃+Y₂O₃ additives at 25[℃]. The electrical resistivity was all negative temperature coefficient resistance (NTCR) in the temperature ranges from 25℃ to 700[℃]. The resistance temperature coefficient of composite showed the lowest value of -2.3×10?³[℃]?¹ for 16[wt%] additives in the temperature ranges from 25[℃] to 100[℃].
常壓燒結한 SiC-ZrB₂ 電導性 複合體의 特性에 미치는 In Situ YAG의 影響
辛龍德(Yong-Deok Shin),朱陣榮(Jin-Young Ju),高台憲(Tae-Hun Ko),李政勳(Jung-Hoon Lee) 대한전기학회 2008 전기학회논문지 Vol.57 No.11
The effect of content of Al₂O₃+Y₂O₃ sintering additives on the densification behavior, mechanical and electrical properties of the pressureless-sintered SiC-ZrB₂ electroconductive ceramic composites was investigated. The SiC-ZrB₂ electroconductive ceramic composites were pressurless-sintered for 2 hours at 1,700[℃] temperatures with an addition of Al₂O₃+Y₂O₃(6 : 4 mixture of Al₂O₃ and Y₂O₃) as a sintering aid in the range of 8 ~ 20[wt%]. Phase analysis of SiC-ZrB₂ composites by XRD revealed mostly of α-SiC(6H), ZrB₂ and In Situ YAG(A1?Y₃O₁₂). The relative density, flexural strength, Young's modulus and vicker's hardness showed the highest value of 89.02[%], 81.58[㎫], 31.44[㎬] and l.34[㎬] for SiC-ZrB₂ composites added with 16[wt%] Al₂O₃+Y₂O₃ additives at room temperature respectively. Abnormal grain growth takes place during phase transformation from β-SiC into α-SiC was correlated with In Situ YAG phase by reaction between Al₂O₃ and Y₂O₃ additive during sintering. The electrical resistivity showed the lowest value of 3.14×10?²Ωㆍ㎝ for SiC-ZrB₂ composite added with 16[wt%] Al₂O₃+Y₂O₃ additives at 700[℃]. The electrical resistivity of the SiC-TiB₂ and SiC-ZrB₂ composite was all negative temperature coefficient resistance (NTCR) in the temperature ranges from room temperature to 700[℃]. Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites.
液狀燒結한 SiC系의 傳導性 複合體의 微細構造와 特性에 미치는 Boride의 影響
辛龍德(Yong-Deok Shin),朱陳榮(Jin-Young Ju),高台憲(Tae-Hun Ko) 대한전기학회 2007 전기학회논문지 Vol.56 No.9
The composites were fabricated. respectively, using 61[vol.%] SiC-39[vol.%] TiB₂ and using 61[vol.%] SiC-39[vol.%] ZrB₂ powders with the liquid forming additives of 12[wt%] Al₂O₃+ Y₂O₃ by hot pressing annealing at 1650 [℃] for 4 hours. Reactions between SiC and transition metal TiB₂. ZrB₂ were not observed in this microstructure. The result of phase analysis of composites by XRD revealed SiC(6H. 3C), TiB₂; ZrB₂ and YAG(Al?Y₃O₁₂) crystal phase on the Liquid-Phase-Sintered(LPS) SiC-TiB₂. and SiC-ZrB₂ composite. β→a-SiC phase transformation was occurred on the SiC-TiB₂ and SiC-ZrB₂ composite. The relative density, the flexural strength and Young's modulus showed the highest value of 98.57[%], 249.42[㎫] and 91.64[㎬] in SiC-ZrB₂ composite at room temperature respectively. The electrical resistivity showed the lowest value of 7.96×10?⁴[Ωㆍ㎝] for SiC-ZrB₂ composite at 25[℃], The electrical resistivity of the SiC-TiB₂ and SiC-ZrB₂ composite was all positive temperature coefficient resistance (PTCR) in the temperature ranges from 25[℃] to 700[℃]. The resistance temperature coefficient of composite showed the lowest value of 1.319×10?³/[℃] for SiC-ZrB₂ composite in the temperature ranges from l00[℃] to 300[℃]. Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites.
자기 통전식 SiC 세라믹 발열체 개발을 위한 기초 특성 연구
신용덕(Yong-Deok Shin),고태헌(Tae-Hun Ko),주진영(Jin-Young Ju) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.11
The composites were fabricated β-SiC and TiB₂ powders with the liquid forming additives of 8, 12, 16[wt%] Al₂O₃+Y₂O₃ as a sintering aid by pressureless annealing at 1,650[℃] for 4 hours. Reactions between SiC and transition metal TiB₂ were not observed in the microstructure and the phase analysis of the pressureless annealed SiC-TiB₂ electroconductive ceramic composites. The relative density, the flexural strength, the Young's modulus and the Vicker's hardness showed the highest value of 82.29[%], 189.5[㎫], 54.60[㎬] and 2.84[㎬] for SiC-TiB₂ composites added with 16[wt%] Al₂O₃+Y₂O₃ additives at room temperature. The relative density of SiC-TiB₂ composites was lowered due to gaseous products of the result of reaction between SiC and Al₂O₃+Y₂O₃. The electrical resistivity showed the lowest value of 0.012[Ω · ㎝] for 16[wt%] at 25[℃]. The electrical resistivity was all negative temperature coefficient resistance (NTCR) in the temperature ranges from 25[℃] to 700[℃].
폐암환자에서 발생한 피하매몰 중심정맥포트 골절 및 색전증 2예
주진영 ( Jin Yung Ju ),조재영 ( Jae Yeong Cho ),임정환 ( Jung Hwan Lim ),조계중 ( Gye Jung Cho ),채동렬 ( Dong Ryeol Chae ),오인재 ( In Jae Oh ),김규식 ( Kyu Sik Kim ),김유일 ( Yu Il Kim ),임성철 ( Sung Chul Lim ),김영철 ( Young C 대한결핵 및 호흡기학회 2007 Tuberculosis and Respiratory Diseases Vol.63 No.5
Totally implanted central venous access devices for chemotherapy (chemoport) are being used increasingly in lung cancer patients. Vascular catheters are associated with various complications including infection, thrombosis as well as spontaneous fractures and embolization of the catheter, which is known as ``pinch-off syndrome``. ``Pinch-off syndrome`` refers to the compression of a subclavian central venous catheter between the clavicle and first rib resulting in an intermittent or permanent obstruction, which can lead to tears, transection, or embolization. We report two cases of fractured and embolized implanted subclavian venous catheters in which the fragments were removed percutaneously. A 62-year-old man presented with back pain with a duration of a few weeks. The chest radiograph revealed complete transsection and embolization of the catheter into the right atrium. In addition, a 47-year-old woman with a chemoport had a grade 3 pinch-off sign in a chest radiograph demonstrating complete transsection and embolization of the catheter into the pulmonary artery. Both cases were managed by retrieving the embolized distal fragment percutaneously and removing the proximal section of the catheter. (Tuberc Respir Dis 2007;63:449-453)