http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 박현국 (검색결과 228 건)
- 무료
- 기관 내 무료
- 유료
-
-
-
-
소결온도 변화에 따른 Binderless-WC 소결체 특성평가
박현국,이정한,장준호,오익현 대한금속·재료학회 2019 대한금속·재료학회지 Vol.57 No.5
In this study, Binderless-WC hard materials were fabricated using the pulsed current activated sintering (PCAS) process for a Friction Stir Welding tool and difficult-to-cut tool application. Tungsten carbide (WC) hard materials are used in various industries and possess a superior hardness compared to other hard materials. They have particularly high melting points, high strength, and abrasion resistance. 100 mm diameter and 5 mm thick binderless-WC hard materials were fabricated using a 30,000 A pulsed current activated sintering machine and 0.3 to 0.5 μm size WC powders. Variation of properties in binderless WC hard materials by sintering temperature were increased slightly for 0.11 to 0.37 um with a grain size and densified completely for 70.0 to 99.5% for a relative density. Consequently, these materials were almost completely dense with a relative density of up to 99.5% after simultaneous application of 60 MPa pressure and an electric current for 2 min at 1600 oC, almost without any significant change in the crystallite size. The average WC crystallite size that was produced through PCAS was 0.37 μm at 1,600 °C. In terms of mechanical properties, considering only the densified sintered body that the hardness and fracture toughness of binderless-WC hard materials were about 2,661.5 kg/mm2 and 3.90 MPa·m1/2, respectively.
-
급속소결 방법을 이용한 마찰교반 접합 툴용 WC-Co 소결체 제조 및 특성 평가
박현국,윤희준,유정한,장준호,손인진,오익현,Park, Hyun-Kuk,Youn, Hee-Jun,Ryu, Jung-Han,Jang, Jun-Ho,Shon, In-Jin,Oh, Ik-Hyun 대한용접접합학회 2012 대한용접·접합학회지 Vol.30 No.6
Using the pulsed current activated sintering method, the WC-10wt.% Co materials were densified using a WC and Co powder. The WC-Co almost completely dense with a relative density of up to 99.5 % after the simultaneous application of a pressure of 60 MPa and an electric current for 3 minutes almost without any significant change in the grain size. The average grain size of about $0.3{\mu}m$. The hardness and fracture toughness at $1000^{\circ}C$ were about $2200kg/mm^2$ and $9.8MPa.m^{1/2}$, respectively.
-
펄스전류활성 소결 공정을 이용한 Ni 함량변화에 따른 WC 소재의 특성평가
박현국,Park, Hyun-Kuk 한국재료학회 2020 한국재료학회지 Vol.30 No.12
Expensive PCBN or ceramic cutting tools are used for the processing of difficult-to-cut materials such as Ti and Ni alloy materials. These tools have a problem of breaking easily due to their high hardness but low fracture toughness. To solve this problem, cutting tools that form various coating layers are used in low-cost WC-Co hard material tools, and researches on various tool materials are being conducted. In this study, WC-5, 10, and 15 wt%Ni hard materials for difficult-to-cut cutting materials are densified using horizontal ball milled WC-Ni powders and pulsed current activated sintering method (PCAS method). Each PCASed WC-Ni hard materials are almost completely dense, with a relative density of up to 99.7 ~ 99.9 %, after the simultaneous application of pressure of 60 MPa and electric current for 2 min; process involves almost no change in the grain size. The average grain sizes of WC and Ni for WC-5, 10, and 15 wt%Ni hard materials are about 1.09 ~ 1.29 and 0.31 ~ 0.51 µm, respectively. Vickers hardness and fracture toughness of WC-5, 10, and 15 wt%Ni hard materials are about 1,923 ~ 1,788 kg/mm2 and 13.2 ~ 14.3 MPa.m1/2, respectively. Microstructure and phase analyses of PCASed WC-Ni hard materials are performed.
-
『Susruta-samhita,Sutrasthana』의 제16장~제37장까지 어역(語釋)을 통한 Ayurveda(아유르베다)에 관한 연구(2)
박현국,서지영,이경원,하홍기,김기욱 대한한의학원전학회 2011 대한한의학원전학회지 Vol.24 No.5
『Susruta-samhita(妙聞集)』是印度傳統醫學最重要的經典著作之一,與『Caraka-samhita(閨羅迦集)』以及成書于八世紀的『Astangahrdaya-samhita(八心集)』(內外科綜合槪要)倂稱``Ayurveda(阿輸吠陀)``的三位長老, 至今仍是當代印度``Ayurveda(阿輸吠陀)`` 正規敎育所采用的主要敎科書. Susruta-samhita(妙聞集)』是卷一總 說46章、卷二病因論16章、卷三身體論10章、卷四治療論40章、卷五毒物論8章、卷六補遺66章等總共186章構成的. 其作者爲蘇斯魯塔(Susruta), 故此書亦稱『Susruta-samhita(蘇斯魯塔本集)』. 『Susruta-samhita』 的成書年代无法確定,雖然不乏認爲其成書年代可以上溯到紀元前若干世紀者,但現今一般傾向于認爲其傳世本的形成是在公元3~4世紀. 不論是想眞正了解``Ayurveda(阿輸吠陀)``,還是想對不同醫學體系做比較、交流方面的硏究,或是全面考察醫學與社會、哲學等等的關系,부부閱讀綜述性的硏究文章與著作總是不구的. 細觀而眞正了解經典原貌時所能體會到的眞實感. 因此, 試圖了飜譯『Susruta-samhita』. 『Susruta-samhita』是用梵語寫的, 所以흔難接近. 以下借助大地原誠玄的1943年日譯本『スシュルタ本集』之第一卷總說 而廖育群的『阿輪吠陀-印度的傳統醫學』「妙聞集·總論篇」的主要內容譯出. 如今西醫體系獲得了普遍性,其他文化圈的傳統醫學消滅了. 然而其中韓醫學和印度傳統醫學``Ayurveda(阿輸吠陀)``仍然保持了生命力. 從而,論者通過飜譯``Ayurveda(阿輸吠陀)``醫學經典卽『Susruta-samhita(妙聞集)』的「總說」,而且要貢獻擴大韓醫學和東洋傳統醫學的范圍.
-
-
박현국,오익현,장준호,손현택,김호성,손인진 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.3
Spark plasma sintering (SPS method) method was used to densify Ti-x wt.% Si compounds materials from Ti and Si powders. Sintered Ti and Ti-x wt.%) Si materials were almost entirely dense with a relative density of up to 100% after applying anelectric current for 11 min under 60 MPa of pressure at 1000 oC. The average grain size of Ti5Si3 compound obtained fromTi-10 wt.% Si powder was of about 35 nm with a hardness of ~ 640 kg/mm2.
-
박현국,연희준,이승민,방희선,오익현 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.3
Using the spark plasma sintering method, WC-6 wt.%Co hard materials were densified using an ultra fine WC-Co powder. The WC-Co was almost completely dense with a relative density of up to 100% after the simultaneous application of a pressure of 60MPa and an electric current for 12 minutes without any significant change in the grain size. The average grain size of WC that was produced through SPS was about 270 nm. The hardness and fracture toughness of the dense WC-Co composites were also investigated.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
