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.

연구논문 : 설화의 전승경로와 변이양상 연구 1 -용주사 관련설화-

김용국 ( Yong Kuk Kim ) 한국문명학회 2009 문명연지 Vol.10 No.1

지체장애인의 신체적 자기개념 측정도구 개발 및 타당화

김용국 ( Yong Kuk Kim ),성창훈 ( Chang Hoon Seong ) 한국특수체육학회 2007 한국특수체육학회지 Vol.15 No.3

본 연구는 지체장애인이 내면화하고 있는 신체적 자기개념의 구성 요인을 확인하고 이를 측정할 수 있는 척도를 개발하여 요인 구조의 타당성을 검증하였다. 이를 위하여 개방형 설문을 통해 지체장애인의 신체적 자기개념 구성요인을 탐색한 김용국과 성창훈(2006)의 연구결과를 기초로 70문항의 예비문항을 작성하였으며, 지체장애인 303명을 대상으로 예비척도에 대한 반응 자료를 수집하였다. 척도의 타당화 과정에서는 문항분석, 탐색적·확인적 요인분석, 문항내적 일관성 검사 및 검사-재검사 등 내적 구조를 검토하였으며, 아울러 남성과 여성지체장애인의 신체적 자기개념 차이, 지체장애운동선수와 비선수간의 신체적 자기개념 차이, 신체활동수준에 따른 신체적 자기개념의 차이 분석을 통하여 외적 관계도 검증하였다. 분석 결과, 지체장애인의 신체적 자기개념을 구성하는 6개 요인(운동유능감, 외모, 건강, 동작능력, 신체감각능력, 체력)을 확증하였으며, 이를 측정하는 18문항 척도의 안정적인 타당성을 입증하였다. 이 결과는 지체장애인이 갖는 신체적 자기개념의 보편성과 차별성 및 지체장애인의 심리 측정적 타당화 논리와 관련하여 논의하였다. The purpose of this study is to develop and validate a measure to assess physical self-concept of the individuals with physical disability. Eight potential dimensions of physical-concept were identified through Yong-Kuk Kim & Chang-Hoon Seong(2006)`s procedures study. They included sport competence, physique, appearance, health, motion ability, physical activeness, physical sense ability, physical fitness realm. Seventy items representing eight dimensions were developed. Item review procedures result in 54-items preliminary version. Data were obtain from a sample of 303 individuals with physical disability. Item analyses, Exploratory analyses, Confirmatory analyses, Internal consistency and test-retest reliability revealed six major dimension of physical self-concept of the individuals with physical disability, including sport competence, appearance, health, motion ability, physical sense ability, physical fitness realm. The final version including 18 items representing the six dimensions. Athletes with physical disability scored higher on most of the dimensions compared to non-athletes with physical disability. The physical disabled who were more active during leisure time scored higher on most of the dimensions compared to those who were less active. And, Disabled Man scored higher on most of the dimensions compared to disabled Women. These results provided evidence of validity of the measure of physical self-concept of the individuals with physical disability.

Biochemical Characteristics and Antimicrobials Susceptibility of Salmonella gallinarum Isolated in Korea

Ki-seuk Kim,Young-ju Lee,Yong-kuk Kwon,Ryun-bin Tak 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

Characteristics and Antimicrobials Susceptibility of Salmonella gallinarum Isolated in KoreaYoung-ju Lee, Ki-seuk Kim1,*, Yong-kuk Kwon and Ryun-bin Tak1Avian Disease Division, National Veterinary Research and Quarantine Service, Anyang 430-824, Korea1College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, KoreaReceived February 13, 2003 / Accepted April 30, 2003J. Vet. Sci. (2003), 4(2), 161-166JOURNAL OFVeterinaryScience*Corresponding author: Ki-seuk Kim College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Korea Tel: 82-53-950-5962, Fax: 82-53-950-5955 E-mail: kimkiseuk@knu.ac.kr

가변 신호시간을 갖는 개선된 신호등 시스템 설계에 관한 연구

정용국,용승일,원충상 한국교통대학교 2015 한국교통대학교 논문집 Vol.50 No.-

Current of a simple traffic light system varies in a certain direction.Standby regardless of whether a certain order to change the signal or increase the vehicle's system is inefficient.This paper tries to design and implement the system of the vehicle according to the amount of variable signal and the presence of vehicle standby.Series of logic circuits using PLD and 74 to control the order of the length of the signal, the signal circuit design.Signal was verified using a breadboard circuit is variable, depending on the amount of atmospheric presence of the vehicle and the vehicle system was implemented.

위삼차신경핵에서 일차구심성 신경섬유 종말부의 미세구조 및 연접양상

배용철,박국필,정경원,박매자,조희중 대한해부학회 1995 Anatomy & Cell Biology Vol.28 No.5

요석 환자에 있어서 혈중 및 요중 칼슘과 요산치 변동에 관한 연구

노용수,김홍섭,양상국,안성수 건국대학교 의과학연구소 2002 건국의과학학술지 Vol.12 No.-

Background: Urinary stone is a world-wide disease and it's prevalence is 1-12%. During the past decade, there has been an expanding research activities in the neglected problem of urolithiasis, and there has been considerable progress in physicochemical and physiologic basis for stone formation, development of improved diagnostic criteria, and formation of new regimen for treatment. Urinary stones are mainly composed of calcium and the most common metabolic abnormalities in calcium stone patients are known to be hypercalciuria and uric acid disorder, especially including hyperuricosuria, which is thought to be important factors in the formation of idiopathic calcium urolithiasis. Method: We evaluated the difference of urinary and serum calcium, uric acid levels between 54 patients with urinary stone and 35 patients of control group as 24 hr urinary metabolic study. Results: Serum and urine calcium levels and uric acid levels of stone former patients were significantly higher than those of controls. The prevalence of hypercalciuria was significantly high in stone former patients. Conclusion: We found that the serum and 24-hour urinary levels of calcium and uric acid were clearly influential factor of the stone formation.

덤벨 들어내리기에서 상지에 작용하는 힘과 모멘트 산출 모델링의 개발

서국웅,김용재,조동욱 釜山大學校 附設 體育科學硏究所 1996 體育科學硏究所 論文集 Vol.12 No.-

The movement lifting up and supporting the object with arm in sports or daily life can bring about the several disease or injure to a joint, bone and muscle for great weight, as you overuse your power. Therefore it is a important study to find out the mechanical structure and principle of arm's movement. Because human's body is different from another object. It is not simple. So biomechanist make clear relation with the power and movement by modelizing each segment of body into a rigid body and by substituting direct kinetics problem for indirect kinetics problem. This study developed the kinetical modeling of right arm's segment at lifting up and down of dumbbell by using korean's data. It is useful to foresee finding out the power and moment in sports movement or daily activity of arm

전문 런닝화 개발을 위한 런닝화 화형 분석 : 2000년 런닝화를 중심으로

서국웅,윤양진,박승범,김용재 부산대학교 체육과학연구소 2000 體育科學硏究所 論文集 Vol.16 No.-

This study was designed to investigate the problem of the existing Running Standard Last for the Male adult and to suggest some useful information for the better design development and construction of running shoes last. The subjects for this study are based on 4 male adults who had the running pattern of rearfoot strike with normal feet. 51 separate measurements of four lasts of running shoe with N, R, AD, AS brand were tested using a 3-mentional measurement. Four running shoes and a barefoot were measured using a pressure distribution measurement. The findings of the study were as follows 1) The N running shoes last was larger than those for R, AD and AS the standard in the 8 items. The AS running shoes last was larger than those of N, R, AD last in the 8 items. The R's last was the biggest in short heel girth and long heel girth. The AD's last was the biggest in seat length and firth toe height 2) In the regional peak pressure of the running sheos, the barefoot and brand running shoes showed the biggest pressure distribution in the hallux, There were the slightest pressure in the medial midfoot and lateral midfoot. 3) The instance of regional peak pressure, the barefoot and the running shoes showed earlier peak pressure for the lateral heel. It was barely possible to measure pressure distribution in medial midfoot. 4) In the light of time percentage of peak pressure distribution measurement in each mask, N running shoes showed the longest time in medial heel, lateral heel, medial midfoot, lateral metatarsal and lateal toes, AD running shoes showed the longest in first metatarsal, second metatarsal and hallux, R running, the longest in second toes. 5) In the maximum force for pressure distribution, barefeet showed the biggest pressure distribution in second metatarsal and R, AD running shoes the biggest in first metatarsal, respectively. 6) In the time of peak pressure distribution measurement, barefeet quickly showed peak pressure distribution in the lateral midfoot. Simultaneously, N. R, AD and AS's running shoes showed peak pressure distribution with barefeet. 7) In the characteristic of the new last's model, bottom length resulted in 276.00mm, stick length 283.29mm, 70% ball mirth 255.12mm, bottom width 91.21mm, toe thickness 30.00mm.

영상분석 및 EMG를 통한 하중운반체계에의 동역학적 연구

서국웅,이중숙,김용재,이훈식 부산대학교 1994 자연과학논문집 Vol.58 No.-

The purpose of this study was to get the quantitative data of effect of two different load carrying system on Kinematics and Kinetics. The subjects for the reseach were 2-adults. The mechanism of each load carrying pattern was measured by a motion analylizer a forceplatform and E.M.G system. The conclusions were as follows from Kinematics Variables and Kinetics Variables. 1. Analysis of computer graphic, on the pack carrying system in walking. It was efficient in 10kg, 15kg fore-backpack carrying system in walking. But, it was not efficient on 20kg, 30kg backpack carrying in walking. Castrocnemius, Tibialis anterior, Vastus lateralis and Vastus medialis are stressed to bend their body foreward. So it occurred fatigue fastly, injuried muscles and joints. 2. Extension and flection angles of the Knee joint and the hip joint on 10kg, 15kg fore-backpack carrying system in walking showed less than those on 20kg, 30kg backpack carrying system in walking. It was efficient on the 10kg, 15kg fore-backpack carrying system in walking. 3. Magnitudes of EMG of Castrocnemius, Tibialis anterior, Vastus lateralis, Vastus medialis, were increased according to increasing weight road and were decreased on the 20kg, 30kg back-pack carrying system in walking.