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.

식이섬유 보충용 식품의 섭취에 따른 여성의 비만관련 체구성 요인 및 배변만족도의 변화

임용택,강선영,김재등,김성수,김재우,이충영,김정모 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.1

The Purpose of this study was to investigate the effect of functional food including dietary fiber supplementation on body composition concerning obesity and defecation satisfaction of women. Twelve young healthy women but had defecation difficulty were participated as a subject. Body weight, %body fat, WHR mesurement and defecation satisfaction questionnaire were performed before and after 2 weeks' supplementation. The results of this study were as follows : First, Body composition concerning obesity such as body weight(p=.0065), % body fat(p =.0004) and WHR(p=.0007) after 2 weeks' functional food including dietary fiber supplementation was decreased significantly. Second, defecation satisfaction functional food including dietary fiber supplementation was increased significantly(p = .0039). This results suggested that functional food including dietary fiber supplementation should be recommended as effective dietary food for persons with obesity and defecation difficulty.

소아의 상완골 원위부 과간 골절

이우석,정환용,김우식,김용찬,전택수,김남현,김규태 대한골절학회 2004 대한골절학회지 Vol.17 No.4

상완골 원위부 과간 골절은 소아에서는 매우 드물게 발생되는 골절로 대부분 주관절의 굴곡상태로 주관절 후방부에 직접적인 충격에 의해 발생하는 것으로 보고되고 있다. 전위가 없거나 경미한 경우 도수적 정복술 혹은 도수적 정복술 후 경피적 핀고정술을 시행하며, 전위가 심한 골절이거나 도수적 정복술이 불가능한 경우 관혈적 정복술 후 핀고정술을 시행하는 것으로 알려져 있다. 저자들은 전위된 상완골 원위부 과간 골절 환아 2예에서 각각 도수적 정복술과 관혈적 정복술 후 K 강선 고정술을 시행하여 만족한 결과를 얻었기에 보고하는 바이다. Intercondylar fractures of the distal humerus are very rare in children. The pattern of the fracture would suggest that the mechanism of injury involves a fall directly on the flexed elbow. Most agree that the undisplaced fracture can be managed conservatively. With increasing displacement and comminution, the opinions tend to differ. We suggest that closed reduction with percutaneous K wire pinning and open reduction with percutaneous K wire pinning offer a satisfactory methods by which to treat displaced intercondylar fracture in children.

Hybrid Light‐Emitting Diodes: Electrically Driven Quantum Dot/Wire/Well Hybrid Light‐Emitting Diodes (Adv. Mater. 45/2011)

Ko, Young‐,Ho,Kim, Je‐,Hyung,Jin, Li‐,Hua,Ko, Suk‐,Min,Kwon, Bong‐,Joon,Kim, Joosung,Kim, Taek,Cho, Yong‐,Hoon WILEY‐VCH Verlag 2011 ADVANCED MATERIALS Vol.23 No.45

<P>Electrically driven hybrid light‐emitting diodes (LEDs) consisting of quantum dots, wires, and wells based on the nanometer‐sized pyramid GaN structure are reported by Taek Kim, Yong‐Hoon Cho, and co‐workers on page 5364. The LEDs exhibit mixed emissions from InGaN quantum dots, wires, and wells formed at the tops, edges, and sidewalls of the pyramids, respectively. The hybrid LEDs containing low‐dimensional quantum structures provide a broad‐band, highly efficient visible lighting source. </P>

인공 건조법에 의한 마른 명태의 품질 개선에 관한 연구 : 2. Some Methods for Hot-air Dehydration of Alaska Pollack 2. 열풍 건조법에 의한 마른 명태 제조

金用根,金敬順,卞在亨,李應昊,梁升澤 釜山水産大學校 1972 釜山水産大學 硏究報告 Vol.12 No.1

북양명태를 원료로서 마른명태를 가공하는 실험을 하여 다음과 같은 결과를 얻었다. 원료를 해동하여 내장을 제거하고, 그대로 29시간 열풍건조하여 마른명태를 가공할 수 있었으며, 제품의 수율은 22% 수분은 18%였다. 또한 원료어를 등갈이한 다음 머리, 내장, 흑막을 제거하고, 염장한 다음 22시간 열풍건조하여 건조시간도 단축할 수 있고, 색택도 좋은 제품을 만들 수 있고, 수율은 약 12%였다. 또한 원료어를 fillet로 처리하여 염장한 다음 열풍건조하므로서 건조시간을 더욱 단축할 수 있었고, 포장 및 조리하기에 편리한 제품을 가공할 수 있었다. 제품의 수율은 어체의 크기에 따라 차이가 있어 10∼22%였다. 그리고 채육기로 육을 채취한 다음 과산화수소를 써서 거품을 일어켜 새로운 형태의 다공성인 박층건제품을 가공할 수 있었고, 이 다공성 박층건제품은 흡수성이 좋아 instatant 식품으로 이용 가능하다는 결론을 얻었다. In this paper, some dehydration methods for frozen Alaska Pollack Theragra chalcogramma were studied. The cabinet type drier was used for the study. Samples were dehydrated for appropriate time at the air temperature of 38 to 40℃ under the air stream of 3m/sec. The frozen samples were defrosted, eviscerated, and hot-air dehydrated for 29 hours. The yield of dehydrated product was about 22% and moisture content was 18%. The brine salted samples which were headed, split and skinned were also hot-air dehydrated under the same conditions. This dehydration process could reduce dehydration time. The yield of dehydrated product was about 12% and moisture content was about 20%. For another method, frozen samples were first defrosted, washed thoroughly to remove dirt, slime and scales, and then beheaded, skinned and filleted. The fillet was dehydrated after brine salting. The yield was 10 to 22% and moisture content was 12%. The tissue of these hot-air dehydrated products such as round, split and fillet were very firm and difficult to reconstitute. In order to obtain dehydrated product of agreeable texture, another dehydration process was examined. Chopped meat was dipped in alkaline solution of 0.4% hydrogen peroxide for 30 minutes and then agitated for 10 minutes. By these treatment the foamy and emulsified minced meat was spread on a nylon net seated on metal tray, drained, and dehydrated. A better result was obtained by this process comparing with other's. This could be explained for the reason that the process resulted in the meat flake porous by which the meat could be rapidly reconstituted. The texture of the porous meat flake was good for a convenience food.

국내 공공부문 설계시공일괄입찰방식의 낙찰자 선정방법 개선에 관한 연구

김만철,서용철,구교진,현창택 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1

Design-Build is considered as the project delivery system to manage construction process more efficiently than design-bid-build. So Korea government has encouraged Design-Build in public sector. But single selection method of weighted criteria doesn't provide the greatest value to owner. Therefore, there is a need to improve selection method to meet owner's needs and project characteristics. This study proposes four types of selection method. Each of selection method is focused on price, qualification, time. The use of these selection methods enable owner to provide the greatest value.

社會施設서비스의 改革과 課題에 關한 硏究

金龍澤 동국대학교 경주대학 1991 東國論集 Vol.10 No.-

Social welfare institution the accumulation of the persons and techniques organized with the purpose of realizing the services set for the subjects of welfare, the function of social welfare service shall be well operated by working smoothly and effectively on the accumulation of such persons and techniques as organized like this. And, as for the service of institution, it might differ according to its kind and the fields of activities. It shall mean the substitude, supplement or replacement either of an individual or the whole family life complying with the hardship of the living function of the family. And, as for the institution, in case modern family requires, they should act as service function as social resources which can be available when necessary. Our institution use to accommodate those in need of help and provide them with clothings, foods and housing ; merely the role of social defensive function. Article 2∼3 of our Social Welfare Business Act reads "Social Welfare institution are the institution, set up for the purpose of carrying out social welfare business." Despitr of the Article, though the kind of institutions by function recently increased and the contents of institution service improvedm, the fact is that only service for the accommodation and protection is being dodne by the Law of Living Protection rather than such educational service as the education, training and rehabilitation and the service which guarantees physical and mental development. The development of social welfare work, along with the change of times, were come through charity, relief, social works and social welfare work, and accordingly, facility work has changed its service function, We can see such change would always have a close relation with the ideology of the times. Having something to do with the essential problems of social welfare, new ideology, that is ; in addition to the ideology for such soecialization of the service as the ideology of normalization, liberty, human right and privacy, the ideology of integration, rehabilitation, mainstream and the socialization of institution have made their appearance as the method of realizing the normalization, and are making attempt to set up the reform for the desirable institution of the 21st Century based on them among advanced welfare states. For the last 30 years in our community, traditional family function, structure, relation, view point of value and the mode of life have greatly changed along with rapid social and economic change. Social system is getting specialized and information oriented, and due to the chang of population structure and appearance of the middle class, the contents of social welfare urge are becoming new and diversified. This type of phenomena is more notable than any other nations, showing up similar tendency to the social welfare desire in advanced nation. Consequently, our community should look into the countrmeasure of welfare based on the reform which is being discussed in advanced nations. The purpose of this Study lies, in an effort to bring about the betterment of the techniques and quality, in looking into the 8ssence of new welfare ideology, in considering the methods and techniques of institution service function and in suggesting the reform and tasks of the problems through the re-scrutiny of today's institution service function, and also in forecasting the features of the 21st Century institution service and in suggesting its directions at this ppint of time when local autonomous system and localization times have come into being.

佛敎의 老人問題에 대한 認識과 그 對策에 관한 硏究

金龍澤 동국대학교 경주대학 1995 東國論集 Vol.14 No.-

In this study, the reason why old ages issues have been made in Korea, the background, and the trend of the welfare policy for old aged are observed for the positive participation of Buddhism in the settlement of old aged issues first. Second, how Buddhism understand the old aged issues in order to actively take part in the troubleshooting of the old aged issues and what kinds of relief thoughs exist for the practice are considered. Third, what types of efforts modern Buddhism is making in order to solve the old aged problems are shown. In last through the suggestion of the subject of Korean Buddhism for the settlement of the problems with old aged, this study aims at the contribution to the development of the Buddhism welfare for old aged. Conclusion 1. The cause of old aged issues in Korea is related to the social change of modernization directly and indirectly and as the society becomes modernized, old aged issues become more serious. 2. Generally Buddhism is regarded not to show proper directions against social changes, however actually Buddhism has already explained the old aged issues included inside of the modern society through Yonki system(PRATITYA SAM UTPADA), one of unique thoughs of Buddhism. 3. Buddhism already has practice ideas and virtues for the settlement of old aged issues, but stays peacefully in a passive present situation, sot here are many points to be improved including the number of facilities for the welfare for old aged, communication system, financing and education to raise experts. And countermeasures are as follows ; 1. Buddhists should change the past inexpert welfare services carried out as missionary works of Buddhism organizations or prays for happiness to systematic, scientific and specialized welfare services for the welfare of old aged. 2. Buddhism welfare projects for old aged should not be performed by an individual Buddhist monk or a believer but by the Buddhist order through active participation and financial supports. 3. In the contents of the welfare services for old aged, financial relief should be prior to mental enlightenment. And in order to make scientific the communication and distribution system of social welfare services, it is recommended to establish and run social welfare centers. 4. In order to solve the problems with the Buddhism welfare for old aged, the education to foster specialists should be accomplished for the survey on social welfare, development of programs and organization of volunteers. And also on the basis of these efforts, systematic, efficient and proper-for-benefiter services shall be performed.

野山을 利用한 葡萄園 造成 및 栽培에 關한 硏究

金圭來,鄭三澤,李容夏,鄭基澤 경북대학교 교육대학원 1976 논문집 Vol.6-7 No.-

The authors studied on the problems concerning to the establishment of vineyard at 25% slopped land with 50㎝ in soil depth. We investigated on the effects of manure, mulching, physiological disorder and personal expenditures for establishment of the vineyard. The results obtained can be summarized as follows; About thirty person per 10a were required for establishment of planting step. Growth of the vine was not different 50-100㎝ of soil depth from over 100㎝ of soil depth. About 30% of selected vine trees showed boron deficiency on the young leaves and flower cluster during early June and that 70% of the vine trees showed blackish berry caused by boron deficiency during early July. The vine mulched with straw, depth of 7㎝ and 15㎝, showed significantly larger shoot growth than that of control. 15kgr. of manure application per tree showed significant difference in growth than 5kgr.of manure, 5kgr. of hen maunre and control polt.

신경망을 이용한 기준모델 적응제어시스템의 설계

김용택,전홍태 중앙대학교 생산공학연구소 1993 생산공학연구소 논문집 Vol.2 No.2

신경망을 이용하여 구성된 기준모델 적응제어기를 제안한다. 본 논문의 목적은 불확실한 상황에서 비선형 플랜트를 제어하기 위함이다. 제안된 적응 제어 기법은 적응기법과 Lyapunov 이론을 기초로한 학습 알고리즘을 이용하여 변화되는 동적환경에서도 안정된 제어동작을 보장한다. 그리고 전방향 신경망 제어기는 전체 시스템의 일부로써, 마치 적응제어기처럼 초기에도 안정된 동작을 보장한다. 제안된 시스템은 두가지의 제어기법을 사용하며, 폐궤한 제어기는 위치, 속도 등의 오차를 감소시키는 방향으로 제어입력을 만들고, 신경망은 폐궤환 제어기가 보상치 못한 오차분을 보상한다. 마지막으로, 제안된 제어시스템을 가지고 2자유도 메니퓰레이터로 모의 실험 검증을 할 것이다. The Neural Network MRAC system is presented. The purpose of this paper is applied to a plant that is to be controlled in a uncertainty environment. The proposed control system has a learning and adaptation ability in the varying environment by using the error back-propagation learning algorithm based on Lyapunov stability theory. And The N.N. regulator is a part of the overall system and is guaranteed to be stable in the initial stage. This control system is divided into the feedforword controller(N.N.regulaotr) and the feed back controller. The feedforword controller has a capability of compensating for the varying mass parameter and the nonlinear terms of gravity, colilori and centifugal term. And the feedback controller works to eliminate errors of position, velocity which the feedforword controller cannot compensate for. Finally, the proposed control system are demonstrated by using the simulation of a two d.o.f. robot manipulator.