나노인덴테이션을 이용한 Ti(C_0.7N_0.3)-NbC-Ni 써멧 구성상의 경도평가

김성원,김대민,강신후,류성수,김형태,Kim, Seong-Won,Kim, Dae-Min,Kang, Shin-Hoo,Ryu, Sung-Soo,Kim, Hyung-Tae 한국분말야금학회 2008 한국분말재료학회지 (KPMI) Vol.15 No.6

The indentation technique has been one of the most commonly used techniques for the measurement of the mechanical properties of materials due to its experimental ease and speed. Recently, the scope of indentation has been enlarged down to the nanometer range through the development of instrumentations capable of continuously measuring load and displacement. In addition to testing hardness, the elastic modulus of submicron area could be measured from an indentation load-displacement (P-h) curve. In this study, the hardness values of the constituent phases in Ti($C_{0.7}N_{0.3}$)-NbC-Ni cermets were evaluated by nanoindentation. SEM observation of the indented surface was indispensable in order to separate the hardness of each constituent phase since the Ti($C_{0.7}N_{0.3}$)-based cermets have relatively inhomogeneous microstructure. The measured values of hardness using nanoindentation were ${\sim}20$ GPa for hard phase and ${\sim}10$ GPa for binder phase. The effect of NbC addition on hardness was not obvious in this work.

이갈이 진단 및 조절용 구내장치의 개발과 신뢰도 조사

김성원,김미은,김기석,Kim, Seung-Won,Kim, Mee-Eun,Kim, Ki-Suk 대한안면통증구강내과학회 2005 Journal of Oral Medicine and Pain Vol.30 No.1

The purposes of this study were to develop and introduce a novel intraoral appliance for bruxism composed of power switch and biofeedback device and further to examine inter- and intra-reliability of the appliance prior to clinical tests. The newly-developed appliance consisted of detection sensors, a central processing unit (CPU), a reactor and a storage unit and a displayer. Compact-sized, waterproof switches were selected as bruxism detection sensor and any sensor activation by clenching or grinding event was processed at the CPU and transmitted, by radio wave, to the reactor and storage unit and triggered auditory or vibratory signal, subsequently producing biofeedback to the patient with bruxism. The data on bruxing event in the storage unit can be displayed on the computer, making it possible analyzing frequency, duration and nature of bruxism. Cast models were obtained from ten volunteers with normal occlusion to evaluate reliability of the appliances. For inter-operator reliability on the intraoral appliances, each operator of the two fabricated the appliance for the same subject and compared the minimal contact forces provoking auditory biofeedback reaction in vertical, lateral and central directions. Intra-operator reliability was also investigated on the appliances made by a single operator at two separate times with an interval of two days. Conclusively, the newly-developed appliance is compact and safe to use in oral circumstance and easy to make. Furthermore, it had to be proven reliability excellent enough to apply in clinical settings. Thus, it is assumed that this appliance with the processor and the storage of data and auditory or vibratory biofeedback function is available and useful to analyze and control bruxism.

수업 지도안 분석을 통한 예비 교사의 수업 전문성 변화

김성원(Seong-Won Kim),이소율(Soyul Yi),이영준(Youngjun Lee) 한국컴퓨터정보학회 2020 韓國컴퓨터情報學會論文誌 Vol.25 No.1

본 연구에서는 TPACK 교육을 통해 예비 교사의 수업 전문성 변화를 분석하였다. 이러한 연구를 위하여 예비 교사 20명을 대상으로 김성원과 이영준(2019)에서 개발한 프로그래밍 기반 TPACK 교육 프로그램을 적용하였다. 수업 전문성 분석을 위하여 예비 교사가 작성한 수업 지도안을 분석 틀을 활용하여 분석하였다. 연구 결과, 1차 수업 지도안에서 예비 교사는 테크놀로지 활용이 저조하며, 지식을 전달하거나 실험하는 수업을 설계하였다. 2차 수업 지도안에서는 테크놀로지 활용이 증가하였지만, 교육적 맥락에 따라 테크놀로지가 활용되지 않았다. 3차 수업 지도안에서 모든 예비 교사가 테크놀로지를 교육적 맥락에 따라 활용하는 것을 확인할 수 있었다. 또한, 예비 교사의 수업 전문성은 통계적으로 유의한 향상이 나타났다. This study analyzed the change of teaching expertise of pre-service teachers through TPACK education. In this study, we applied a programming-based TPACK education program developed by Kim and Lee (2019) to 20 prospective teachers. To analyze the pre-service teachers’ teaching expertise analyzed the lesson plan prepared before, during and after applying the educational program. As a result, Few teachers use technology in lesson plan, and the design of the instructor-led or experiment to confirmed content in curriculum or textbook. The use of technology has increased in the second Teaching Plan, but the technology was not used depending on the educational context. In the third lesson plan, all pre-service teachers were able to use technology in an educational context. Moreover, the teaching expertise of the pre-service teacher showed a statistically significant improvement in the lesson plan. This study founded that the programming-based TPACK education program was effective in enhancing the teaching expertise of the pre-service teacher.

실리콘 나노선/다중벽 탄소나노튜브 Core-Shell나노복합체의 합성

김성원,이현주,김준희,손창식,김동환,Kim, Sung-Won,Lee, Hyun-Ju,Kim, Jun-Hee,Son, Chang-Sik,Kim, Dong-Hwan 한국재료학회 2010 한국재료학회지 Vol.20 No.1

Si nanowire/multiwalled carbon nanotube nanocomposite arrays were synthesized. Vertically aligned Si nanowire arrays were fabricated by Ag nanodendrite-assisted wet chemical etching of n-type wafers using $HF/AgNO_3$ solution. The composite structure was synthesized by formation of a sheath of carbon multilayers on a Si nanowire template surface through a thermal CVD process under various conditions. The results of Raman spectroscopy, scanning electron microscopy, and high resolution transmission electron microcopy demonstrate that the obtained nanocomposite has a Si nanowire core/carbon nanotube shell structure. The remarkable feature of the proposed method is that the vertically aligned Si nanowire was encapsulated with a multiwalled carbon nanotube without metal catalysts, which is important for nanodevice fabrication. It can be expected that the introduction of Si nanowires into multiwalled carbon nanotubes may significantly alter their electronic and mechanical properties, and may even result in some unexpected material properties. The proposed method possesses great potential for fabricating other semiconductor/CNT nanocomposites.

나노인덴테이션으로 측정한 Ti(C_0.7N_0.3)-WC-Ni 써멧 구성상의 경도

김성원,김대민,강신후,김형준,김형태,Kim, Seong-Won,Kim, Dae-Min,Kang, Shin-Hoo,Kim, Hyeong-Jun,Kim, Hyung-Tae 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.1

The constituent phases in Ti($C_{0.7}N_{0.3}$)-xWC-20Ni (wt%, x=5, 15, 25) cermets were characterized using nanoindentation in conjunction with observation of microstructure. The microstructure of cermet is composed of hard phase and binder phase, which gave rise to a wide range of hardness distribution when nanoindentation was carried out on the polished surface of cermets. Because of the inhomogeneous nature of cermet microstructure, observation of indented surface was indispensable in order to separate the hardness of each constituent phase. The measured values of hardness using nanoindentation were ${\sim}14\;GPa$ for the binder phase and ${\sim}24$ to 28 GPa for the hard phase, of which nanoindentation hardness was decreased with the addition of WC into Ti($C_{0.7}N_{0.3}$)-Ni system. In addition, the nanoindentation hardness of Ni binder phase was much higher than reported Vickers hardness, which could result from confined deformation of binder phase due to the surrounding hard phase particles.

포털 도서검색서비스 대응방안에 대한 연구 - 구글도서검색을 중심으로 -

김성원,Kim, Sung-Won 한국도서관정보학회 2011 한국도서관정보학회지 Vol.42 No.1

방대한 이용자 기반을 지닌 인터넷 검색 포털인 구글은 도서검색(Book Search) 서비스를 제공하고 있다. 구글은 도서검색서비스의 제공에 필요한 정보자원의 확보를 위해 출판계 및 도서관계와 협력을 추진하고 있다. 출판계와는 출판사가 저작권을 보유한 도서의 이용을 목적으로 협력하고 있으며, 도서관계와는 도서관이 소장한 장서의 디지털화 및 디지털로 변환한 자료의 활용을 위해 협력하고 있다. 구글도서검색 서비스는 방대한 이용자 규모에 기반을 두는 구글의 영향력에 따른 독점의 위험성과 독점에 따라 야기될 수 있는 잠재적인 문제점들로 인해 많은 논란을 빚고 있다. 본고에서는 이러한 구글도서검색과 관련하여 도서관계가 취해야 할 대응방안을 정리하여 제시하였다. Google, an internet search service with extensive user base, has provided Book Search service. Google has pursued collaboration with publishers and libraries to obtain content for Book Search service; publisher community for the purpose of sourcing the books with copyrights, and the libraries for the purpose of digitizing their collections and also utilizing already digitized resources. Google Book Search Service has evoked significant controversy because of the potential monopoly problems and its risk, accompanied by Google's huge influence and broad user spectrum. This study, thus, suggests the countermeasures that library community should prepare in order to cope with the Google Book Search.

Reconstitution of Iron Cores in Horse Spleen and Yeast-derived Recombinant Human H- and L-chain Ferritins

김성원,Min-Young Jo,Yasuhiro Yokota,Yun-Jo Chung,Chung-Ung Park,Kyung-Suk Kim* 대한화학회 2004 Bulletin of the Korean Chemical Society Vol.25 No.2

우리나라 과학교육 위기 심각하다

김성원,Kim, Seong-Won 한국과학기술단체총연합회 2005 과학과 기술 Vol.38 No.8

플랫폼으로 살펴보는 DOOH 마켓과 동향

김성원,Kim, Seong-Won 한국스마트미디어학회 2012 It's Smart Media Vol.1 No.3

시계열자료의 계층분리기법을 이용한 하천유역의 홍수위 예측

김성원,Kim. Sung-Weon 한국방재학회 2008 한국방재학회 학술발표대회논문집 Vol.2008 No.1

In this study, the new methodology which combines Kohonen self-organizing map(KSOM) neural networks model and the conventional neural networks models such as feedforward neural networks model and generalized neural networks model is introduced to forecast flood stage in Nakdong river, Republic of Korea. It is possible to train without output data in KSOM neural networks model. KSOM neural networks model is used to classify the input data before it combines with the conventional neural networks model. Four types of models such as SOM-FFNNM-BP, SOM-GRNNM-GA, FFNNM-BP, and GRNNM-GA are used to train and test performances respectively. From the statistical analysis for training and testing performances, SOM-GRNNM-GA shows the best results compared with the other models such as SOM-FFNNM-BP, FFNNM-BP, and GRNNM-GA and FFNNM-BP shows vice-versa. From this study, we can suggest the new methodology to forecast flood stage and construct flood warning system in river basin.