Study on Microstructure and Mechanical Properties of the Al–25Cr–5Si (at%) Alloy Powder Using Gas-Atomization and SPS Process

Yong‑Ho Kim,Hyo‑Sang Yoo,Jeong‑Han Lee,Ik‑Hyun Oh,Hyun‑Kuk Park,Hyeon‑Taek Son 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

In order to investigate the microstructure and mechanical properties on Al–25Cr–5Si (at%) alloy, a mixed powder with pureelements and an alloy powder using a gas atomization process were used. Fine and high purity Al–25Cr–5Si (at%) alloypowder was successfully prepared by gas atomization and densified using a spark plasma sintering (SPS) process. The overallpowder size distribution of the mixed Al, Cr, and Si elemental powders was in the range of 10–15 μm. The atomized Al–Cr–Sialloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Densification wasclearly confirmed at 1000 °C, with almost isolated pores formed, by clear removal of pores between particles, deformationof particles, an increase in the number of contacts, and a change in size between particles. As a result of XRD analysis ofthe sintered compacts, single phase was observed using the mixed powder, but the compact using gas atomization remainedthe alloy phase even at the process temperature. The Vickers hardness of the compacts by mixed powder was observed at59.70 Hv and the compact using gas atomized powders on the temperature 1000 °C of the Vickers hardness increased to702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strengthof the compact with gas atomized powder increased to 802.07 MPa. It is considered not to be decomposed by the AlCrSi,Al13Cr4Si4and Al8Cr5phases sintering process, resulting from the improvement of mechanical properties.

외상성 대장 및 직장 손상

김익용,김상희,윤광수,김히욱 대한대장항문학회 1997 Annals of Coloproctolgy Vol.13 No.3

濟州地方에 있어서 마늘栽培法 改善에 관한 硏究 : 3. 濟州地方 마늘의 栽培時期에 따른 鱗片特性 3. The clove Characteristics of Cheju Local Garlic on Planting Time

張田益,朴庸奉 제주대학교 1980 논문집 Vol.12 No.-

The present experiment was conducted during the period from August 27, 1979 to June 5, 1980, in order to examine the suitable planting time in Jeju Island. The results are as follows : 1. Top part growth increased continuously into the middle of May. After that, it decreased. The earlier the garlic was planted, the higher the plant height, leaf height and leaf width in each plant. 2. In the underground part growth, the earlier the garlic was planted the higher the plant weight, bulb weight, bulb diameter and neck diameter. However, bulb height and neck diameter also showed good growth by 30, October. 3. Because the bulb index was below 0.5 in the bulb formation, no difference showed during the seeding period. 4. The number of primary cloves per bulb (out layer+inner layer) appeared to be similar until 30, Oct, but in the number of secondary cloves there was little difference during the seeding period. 5. The plot of cut seedstalks more than uncut seedstalks increased bulb height, bulb diameter and neck diameter. Both of them appeared similar in bulb formation ratio.

창의력 개발을 위한 초등실과 교수·학습자료의 개발

김용익,박행모,방기혁 光州敎育大學校 初等敎育硏究所 2002 初等敎育硏究 Vol.17 No.-

The purpose of this study was to develop instructional materials for the development of creativity through practical arts subject. This study was carried out mainly through literature review. The concept of creativity was organized as creativity domain(X axis) including cognitive and affective one, creativity dimension(Y axis) including historical creativity and psychological creativity, and the viewpoint of creativity level(Z axis) including novelty and appropriateness. In the future, creativity education in practical arts subject should be more emphasized because of creativity development education through practical arts subject was more effective than through other subjects. Most of preceding researches related to creativity in practical arts subject dealt with instructional model and guidance for creativity rather than development of various instructional materials. This study explored Treffinger's instructional model which was composed of difficulty finding, data finding, problem finding, solution finding, and acceptance finding. And, Instructional guidance plan related to 'woodworking lesson' was made at base of the model. Besides, other instructional materials for the improvement of creative thought was concretely presented. Finally, it was suggested that more instructional materials should be developed and a test for effectiveness of such a creative program should be made afterward.

F. Kafka 作品의 共有的 特性

金容翊 釜山大學校 1981 人文論叢 Vol.20 No.1

<Zusammenfassung> Die Methode Kafkas, alles in der Wirklichkeit subjektiv zu verstehen und der verstan-denen Welt die vorgetäuschtr Objektivität wieder zu geben, läβt uns die wahren Ges-talten von den Absichten des Dichters undvon der protokollarisch dargestellten Welt nicht erkennen. Kafka verzichtet bewuβt auf die Darstellung der gesamten Wirklichkeit und konzentriert sich auf die wesentlichen Elemente, d. h. auf einige der Komponenten und Tendenzen, die er für wesentlich hält. Aus dieser Methode Kafkas ergeben sich die Ambivalenz, der Widerspruch, die Nicht-Übereinstimmung, besonders die pluralistischen Kafka-Rezep-tionen u. s. f. Wie und wann können wir die festgestellte Deutungsrichtung zum Maβstab der Kafka-Wertung machen?

혈관질환 정보관리 시스템

김동익,김덕경,허세호,이병붕,김용신,김은숙,문지영,도영수,신성욱,김동수,김만태,진재욱,김용신 대한혈관외과학회 2002 Vascular Specialist International Vol.18 No.1

As medical technology progresses rapidly, there is a rise in the average age along with the Korean dietary lifestyle becoming more westernized, which leads to an increase in the number of vascular disease patients in Korea. Thus, we need to manage the medical information of a disease systematically in order to diagnose and treat constructively. However, since there has been no standardized method of man agement to date, a great deal of information could not be properly utilized nor studied. Therefore, the departments of Cardiology, Radiology and Neurology of Samsung Seoul Hospital recently got together to develop an information management system called the Vascular Data System. This program was developed to be run on win98 O/S, upper Pentium Ⅲ, and upper 128 MB Memory, and its source code is Dephi 4.0. It was configured for the user to set the configurations as well as do a variety of search and analysis. If this program were to be updated continuously, it may be used extensively as well as in various parts of clinical research activities.

실과 생활 기술 영역의 수행 평가 방안 탐색

김용익 韓國實科敎育硏究學會 1999 實科敎育硏究 Vol.5 No.3

The Purpose of this study were to identify a performance assessment types that could be applied well to the living technology part, and to show a performance assessment method and some available examples, and to suggest some ideas in making a performance assessment efficiently fitted. The major conclusions of the study were as follows; 1) Types of performance assessments that could be applied to the living technology part were identified as 'description and discourse type', 'research report method', 'practicing test', 'practicing method', and 'portfolio'. 2) A practicing test among performance assessment types was found to be most used effectively in the living technology part. 3) An improvement of teachers' practicing competence and an establishment of practicing facilities and equipment should be done to make a performance assessment fitted in the educational field. 4) Teachers' role and responsibilities are most important to make a performance assessment fitted, so assessment rights should be given to them fully.

제주도 해안의 수중소음- I : 제주항과 추자도사이

정용진,변창익,서두옥 제주대학교 해양연구소 1986 해양자원연구소연구보고 Vol.10 No.-

크레인의 능력을 고려한 MOB 자동창고 시스템의 저장과 불출정책

조용환,손권익 江原大學校 産業技術硏究所 1996 産業技術硏究 Vol.16 No.-

This paper deals with storage and retrieval policies for S/R machine with capacity constraints in Man-On-Board AS/RS. It is assumed that storage sequence is based in SFC(spacefilling curve) routine and that storage layout is dedicated by storage policies. We present several heuristic algorithms for storage and retrieval policies which minimize total distance travelled by the S/R machine. These algorithms are based on COI.group COI, frequency of order, similarity between items and capacity of S/R machine. Experimental results of 24 combinastorial policies are provided to illustrate the performance of the heuristics under various rack utilization ratio. In storage policies, the results show that algorithms considering both similarity and frequency are better than those with COI as rack utilization is increasing. And algorithm using group COI is superior to others. In retrieval policies, the method with revision expression is shown to be better than others.

수두 피부병변에 대한 재조합 알파 인테페론 연고의 치료 효과에 관한 연구

신용우,이증훈,고익준 대한감염학회 1989 감염 Vol.21 No.1

This clinical study was carried out to evaluate therapeutic effect of the recombinant interferonalpha (IFN-α) cream in the treatment of the varicella skin lesion. The IFN-α and placebo creams were topically applied 2 times a day on the early erythematous maculo-papular lesions and the already advanced vesicular lesions of the 52 patients with varicella. The therapeutic efect was evaluated by comparing the healing periods, namely, the mean number of days required for the disappearance of the erythematous maculo-papular lesions without vesicular formation or for the crust formation through vesicular changes. The results were summarized as follows; 1) For the early erythematous maculopapular lesions, the healing periods of the IFN-α and the placebo creams were 3.05±2.76 and 4.72±3.48 days, respectively (p < 0.005). 2) For the advanced vesicular lesions, the healing periods of the IFN-α and placebo creams were 3.52±2.47 and 4.48±3.01 days, respectively (p < 0.05). During the study, and local or general side reactions were not observed. Therefore, with above results, it is suggested that topical IFN-α cream may be an effective and safe therapeutic agent for the treatment of varicella, especially in the case of the early erythematous maculo-papular lesions.