Effects of I- and W-Phases Under Identical Conditions on Microstructure and Mechanical Properties of As-Cast Mg–Zn–Y Alloys at Room and Elevated Temperatures

Young‑Gil Jung,Wonseok Yang,Jae Ik Hyun,Shae K. Kim,Hyunkyu Lim,Do Hyang Kim 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

Three alloys (Mg–6Zn–1.2Y, Alloy I; Mg–3.65Zn–1.65Y, Alloy II; and Mg–4.3Zn–1.4Y, Alloy III) with same volume fractionand grain size were designed to evaluate the effects of the I-phase (Mg3Zn6Y) and W-phase (Mg3Zn3Y2), which are themajor phases in Mg–Zn–Y alloys, on the mechanical properties. The tensile strength of Alloy I with the I-phase at roomtemperature was the highest among the tested alloys because the coherent interface between the I-phase and the α-Mg phasewas more resistant to cracking than the incoherent interface between the W-phase and the α-Mg phase. A cross-sectionalmicrostructure analysis of a sample that was tensile-tested at 423 K revealed that the morphology of the I-phase remainedrelatively stable. In contrast, the W-phase was broken and fragmented during the tensile test at 423 K because it had higherbrittleness under the test conditions. Therefore, the tensile and creep properties of Alloy I at 423 K were better than thoseof Alloys II and III containing the W-phase. According to the results, the I-phase in the Mg-Zn-Y alloy was more beneficialto the mechanical properties at room temperature and 423 K than the W-phase.

대동맥 협착증과 동반된 출혈성 위장관 동정맥 기형에서 Estrogen-Progesterone 치료 1예

김도연,김화정,김효정,남준식,박수영,박영미,신정은,주미순,황민규,정혜경,손혜영,이선영,이한주 大韓消化器內視鏡學會 1999 Clinical Endoscopy Vol.19 No.부록2

영상 정보를 이용한 자율 주차 시스템에 관한 연구

김영민(Young-min Kim),강희정(Hee-jung Kang),방상우(Sang-woo Bang),임영도(Young-do Lim) 한국정보기술학회 2010 한국정보기술학회논문지 Vol.8 No.5

Generally parking of the vehicle only driver sight and in compliance with an experience comes to do the spatial security which is caused by with judging distance and the camera which are accurate the various sensor, but it in recent times is caused by with technical advancement and leads was possible, parking was quicker and safely there made be a possibility of doing. So about unmanned parking the research vehicle with technical advancement and in standard to be advanced from the side which is various comes. In this paper the parking sector from the public parking lot or the formation parking market is clear and importance in the space where the unmanned camera is established in the parking sector depends in real-time image value and is parks autonomously. The camera which is established in the parking sector guard and the vehicle of parking space, recognized the object with real-time image processing and the vehicle wheel track angle in compliance with a image data and presumed Fuzzy-control led and in the four-wheel mobile robot and parking a production value and got applied accomplished.

랜덤포레스트를 이용한 낙동강 본류의 남조류 발생 영향인자 분석

정우석(Jung, Woo Suk),김성은(Kim, Sung Eun),김영도(Kim, Young Do) 한국습지학회 2021 한국습지학회지 Vol.23 No.1

본 연구에서는 랜덤포레스트를 이용하여 8개 보 지점별 남조류 발생 주요 영향인자를 도출하고, 조류경보제 기반의범주형 예측모델을 개발하였다. 8개 보 지점의 랜덤포레스트의 변수 중요도를 살펴본 결과, 상류의 보 지점들은 남조류 발생에 있어 보 운영에 따른 영향을 직접적으로 받는 것으로 나타났다. 이는 효율적인 보 운영을 통한 남조류 관리가 가능할 수 있다는 것을 의미한다. 중류 구간은 DO와 E.C가 주요 영향인자로 도출되었다. 공간적으로 구미와 김천에 대규모 산업공단들이 밀집되어 있으며, 환경기초시설의 배출량이 큰 영향을 끼치는 구간이다. 따라서 폭염 및 가뭄 시기에 중류 유역에서 배출되는 환경기초시설의 방류는 본류의 E.C를 증가하게 하고 남조류 발생을 촉진 시키는것으로 나타났다. 중·하류에 위치한 보 지점들은 폭염 및 가뭄의 영향을 가장 많이 받는 지역으로 여름철 가뭄에 따른남조류 대발생에 대비하여 선제적인 관리가 필요한 지점으로 나타났다. 본 연구를 통해 지점별 남조류 발생 영향인자를 도출하였으며, 맞춤형 조류관리를 위한 정책적 의사결정의 기초자료로 제공될 수 있을 것으로 판단된다. In this study, the main influencing factors of the occurrence of cyanobacteria at each of the eight Multifunctional weirs were derived using a random forest, and a categorical prediction model based on a Algal bloom warning system was developed. As a result of examining the importance of variables in the random forest, it was found that the upstream points were directly affected by weir operation during the occurrence of cyanobacteria. This means that cyanobacteria can be managed through efficient security management. DO and E.C were indicated as major influencers in midstream. The midstream section is a section where large-scale industrial complexes such as Gumi and Gimcheon are concentrated as well as the emissions of basic environmental facilities have a great influence. During the period of heatwave and drought, E.C increases along with the discharge of environmental facilities discharged from the basin, which promotes the outbreak of cyanobacteria. Those monitoring sites located in the middle and lower streams are areas that are most affected by heat waves and droughts, and therefore require preemptive management in preparation for the outbreak of cyanobacteria caused by drought in summer. Through this study, the characteristics of cyanobacteria at each point were analyzed. It can provide basic data for policy decision-making for customized cyanobacteria management

탄성반력의 영향에 따른 직교 이방성 복합판의 고유 진동 해석

정영화,심도식,김경진,이세진 江原大學校 産業技術硏究所 1997 産業技術硏究 Vol.17 No.-

In this paper, the result of application of vibration method to the orthotropic plates with free edges supported on elastic foundation and with a pair of opposite edges under axial forces is presented. Such plates represent the concrete highway slab and hybrid composite pavement of bridges. The reinforced concrete slab can be assumed as a special orthotropic plate, as a close approximation. The highway slab is supported on elastic foundation, with free boundaries. Sometimes, the pair of edges perpendicular to the traffic direction amy be subject to the axial forces. The plate is subject to the concentrated load/loads, in the form of traffic loads, or the test equipments. Finite difference method is used to obtain the deflection influence surfaces needed for vibration analysis. The influence of the modulus of the foundation, the aspect ration of the plate, and the magnitudes of the axial forces and the concentrated attached mass on the plate, under the natural frequency is thoroughly studied.

고효율을 갖는 스위치드 리럭턴스 모터에 관한 연구

정도영,이상호,정의남,심낙순 三陟大學校 産業科學技術硏究所 1999 産業科學技術硏究論文集 Vol.4 No.-

The switched reluctance motor(SRM) has a simple rotor construction with no windings. It also has simple concentrated windings on the stator. Thus, it is expected to be a lower cost machine to manufacture than the squirrel cage induction motor. This paper analyzed the torque of SRM including two different rotor and stator structure according to the phase current. The analyzed SRM are two types, that is, rectangle so called typical type and well-rounded type in SRM. To design and analyze the improved SRM effectively, we used FEM and compared with each other. And we presented the well-rounded type SRM as a high torque SRM. In the point of view of the static torque, instantaneous torque and average torque, the well-rounded type SRM is more improved than that of typical type which has been generally used for SRM.

만성두통환자에 대한 아로마침의 임상적 연구

정인태,김수영,김건식,이두익,이재동,이윤호,최도영 WHO COLLABORATING CENTRE FOR TRADITIONAL MEDICINE 2004 東西醫學硏究所 論文集 Vol.2004 No.-

Objective : Because the cause and etiology of chronic headache is not yet fully explained, the treatment of this symptom is not simple. This study compares the effects of aroma acupuncture and normal acupuncture applied an chronic headache patients, in order to establish a primary data for further studier of new treatments and developments of new practical acupunctures. Methods : 38 clinical experiment participants were gathered and through a questionnaire patients who experienced headache for more than 4 hours a day and more than 15 days per month were qualified as Chronic Headache patients. The qualified patients were classified in to two groups, aroma acupuncture group(Aroma AT group, n=23) and normal acupuncture group(AT group, n=15). Treatment was applied 2 times a weeks for 8 weeks. The acupoints, GV20, HN23, ST8, HN46, TE17, GB20, LI20, LI11, LI14, ST36, and LR3 were stimulated for 20 minutes in both the groups. The effects of both groups were analyzed using VAS scores and BPI(Brief Pain Inventory). Results : The VAS pain scores improved significantly in both groups. The decrease rate was larger in the Aroma AT group(p<0.05). The BPI scores for the both groups also decrease. The improvement in the Aroma AT group was larger(p<0.05). Conclusion : Aroma acupuncture applied on chronic headache patients showed effects of relieving pain, improving general activities, changing the mood, and improving sleeping behaviors. These effects were analyzed using VAS scores and BPI. The Aroma AT group showed significant changes of VAS and BPI compared to the AT group, suggesting that this new practical acupuncture is very effective when treating chronic headaches. Further researches are needed to evaluate the distinct functional mechanism of aroma acupuncture, but this study is meaningful in the sense that it will act as a fundamental study to build on.

유한요소법을 이용한 볼트결합 구조부의 조건에 따른 동적변화 해석

鄭泳都,朴世蔓,朴明均 明知大學校 産業技術硏究所 2003 産業技術硏究所論文集 Vol.22 No.-

To join structure together, various methods and processes are available including welding, riveting, bonding with industrial adhesives and fastening by bolts. Analysis of the common areas formed by joining between the structure are significant in that their results can provide critical information for understanding the dynamic behavior of the whole structure. The structural factors affecting the dynamic behavior of the joined structures are usually believed to be materials composing the bolts, bolt sizes and the number of bolts as well as the strength of applied torque and the extent of overlap between the structures joined together. This paper analyzes the impacts of the structural factors such as the bolt sizes, the extent of overlap and the materials composing the structures on the dynamic behavior of the joined structures.

회전자 구조에 따른 SRM의 토오크 특성해석

정도영,이상호,서진우,오홍석,최경호 三陟大學校 1997 論文集 Vol.30 No.1

The switched reluctance motor(SRM) has a simple rotor construction with no windings. It also has simple concentrated windings on the stator. Thus, it is expected to be a lower cost machine to manufacture than the squirrel cage induction motor. This paper presents an advanced rotor structure type, well-round rotor type in SRM. To design the improved SRM we have used FEM and studied and compared with each other. The static torque, instantaneous torque and average torque are more improved than that of typical rotor type which has been a lot of used for SRM.

유한요소해석을 통한 iTECH의 전단 성능에 관한 해석적 연구

정재오,김도현,주영규,이재홍,김상대 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2(구조계)

Experimental evaluations for the iTECH beam System, which is invented for the purpose of making a lower height in steel structures, have been studied a lot for many years. In addition, they show the possibility of being developed as a new system when the iTECH beam system is applied in construction fields. However, the experiments were carried out without preceding theoretical analyses. Thus, it is intended to supplement some parts of the experiments by analyses and to provide the basis on future studies. iTECH Beam evaluated structural function through moment, shear, joint experiment and proposed formula. While this experiment, shear formula proposed assuming that steel web is all shown similar shear behavior about shear component element. This paper tries to verify assumption for analyzing shear behavior through FEA method.