원격조작에 의한 작업대상물 강성과 마찰 특성의 동정

권혁조,전지명,김진옥,문일동,오재윤 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2002 工學硏究 Vol.33 No.-

This study performs a workpiece stiffness and frictional characteristic identification experiments by teleoperation. Experiments are performed using a bilateral force feedback teleoperation system. It is composed of a master manipulator, the slave manipulator equipped with a force/torque sensor, and a real-time control system. To control the teleoperation system, a position-force controller is developed. The slave manipulator is controlled by the master manipulator's position command and the master manipulator is controlled by the force information from the slave manipulator. This study presents a method to find the slave manipulator's stiffness. And, this study presents a method to compute the workpiece stiffness based on the measured pressing force and deflection at the slave manipulator. Also, this study performs a workpiece frictional characteristic identification experiments. In the experiments, the slave manipulator rubs a workpiece with an arbitrary pressing force. While the slave manipulator rubs a workpiece, a vertical force and a frictional force are measured and the ratio of a frictional force to a vertical force is considered as a frictional characteristic.

어린 가토에서 자가 연골 이식후 연골성장에 관한 실험적 연구

권택근,김태연,정전은,이동진 대한성형외과학회 1992 Archives of Plastic Surgery Vol.19 No.3

Does free transplanted autologous cartilage grow? Until now many autors have published different results about the growth potential of cartilage. Some authors have produced in their study that transplanted cartilages were able to grow, but others showed contradicting results. In this study, authors obtained cartilages from young rabbits'ear, 10 by 10mm in size and divided them into two groups ; the first group was cartilages with perichondrium and the second group was cartilages stripped perichondrium. We transplanted both groups of cartilages in the posterior nuchal area of rabbits. Then numbers of specimens of each group were evaluated and compared for assessment of cartilage growth. After observaton for six months, we took the cartilages from the posterior nuchal area and examined the surface area, the thickness, and the weight and finally confirmed the growth potential of the cartilage by histologic study. The results are as follows : 1, The surface area, the thickness, and the width of the transplanted cartilages were increased significantly in gross specimens and their measured values were statistically significant and cartilages with perichondrium showed more growth than cartilages stripped perichondrium 2. In histologic studies, we observed increased surface activities with numerous proliferatng cells and found no abnormal features compared with normal cartilages. Cartilages with pericondrium were thicker than cartilages with stripped perichondrium

다중화된 광섬유 BG 센서에 의한 변형률의 측정

권일범,김치엽,윤동진,이승석 한국비파괴검사학회 2003 학술대회 논문집 Vol.- No.1

FBG(Fiber Bragg grating) sensor, which is one of the fiber optic sensors for the application of smart structures, can not only measure one specific point but also multiple points by multiplexing techniques. We have proposed a novel multiplexing technique of FBG sensor by the intensity modulation of light source. This technique is applicable to WDM(Wavelength Division Multiplexing) technique and number of sensors in this system can be increased by using this technique with WDM technique

음향방출을 이용한 저어널 베어링의 조기파손감지(Ⅱ) : Part Ⅱ : Intervention of Foreign Particles in Lubrication 윤활유 이물질 혼입의 영향 및 감시

권오양,윤동진,김경웅,정민화 韓國非破壞檢査學會 1994 한국비파괴검사학회지 Vol.14 No.2

일반적으로 회전기기의 저어널 베어링 부분은 윤활유 공급의 부족이나 윤활층에 이물질이 혼입되면 시스템의 고장이나 가동중단 등의 원인이 되기도 한다. 따라서 베어링 손상에 기인하는 사고와 관련된 안전운전 문제와 유지비용의 절감을 위해 여러가지 파괴 및 비파괴시험법들이 사용되어 왔다. 본 연구에서는 저어널 베어링에서 가장 발생하기 쉬운 윤활층에의 이물질이 혼입에 의해 야기되는 베어링 파손의 조기검출을 위해 음향방출 기술을 적용하였으며, 전보의 연구에 이어 좀더 정량적이고 체계적인 실험을 수행하였다. 실험실용으로 직접 제작한 모의베어링 시스템을 이용하여 여러 형태의 인위적인 이물질 흔입 상태를 만들어 실험하였으며 베어링 손상 및 결함 형태의 해석을 위해 AE rms level, 파형분석, AE 변수 등의 여러 파라메터를 사용하여 분석 고찰하였다. 그 결과 AE rms level의 변화가 이물질 흔입의 영향에 민감함을 보여주었으며 AE변수등 다른 정보들로부터 손상 원일별로 신호형태를 확인할 수 있었다. Journal bearings in the rotating machineries are vulnerable to the contamination or the insufficient supply of lubricating oil, which is likely to be the cause of unexpected shutdown or malfunction of these systems. Various destructive and nondestructive testing methods had been used for the reduction of maintenance cost and the operational safety problems due to the accidents related to bearing damages. In this experimental approach, acoustic emission monitoring in employed to the detection of incipient failure caused by intervention of foreign particles most probable in the journal bearing systems. Experimental schedules for the intervention of foreign particles was composed to be more quantitative and systematic than last study in consideration of minimum oil film thickness and particle size . The experiment was conducted under such designed conditions as inserting alumina particles to the lubrication layer in the simulated journal bearing system. Several parameters such as AE rms level, waveform, AE energy distribution and other AE event parameter are used for analysis and characterization of damage source. The results showed that the history of damage was well correlated with the changes of AE rms level and the types of damage source signal can be verified using other informations such an waveform, distribution of AE parameter etc.

Paste법에 의한 0.1V강의 침붕처리에 관한 연구

권동일,김강형,김진관,이성훈,윤재홍 國立 昌原大學校 産業技術硏究所 1994 産技硏論文集 Vol.8 No.-

0.1V강의 표면경도를 향상시키기 위해서 Boronizing처리를 실시하여 Hv=1500∼2000의 높은 경도값을 나타내는 붕화물층을 얻었다. 붕화물층의 두께와 처리시간과의 사이에는 방물선관계를 나타내었으며 붕화물층 생성 겉보기 활성화에너지는 94kJ/mol이다. 또한 900˚C, 3시간 침붕처리했을 때가 가장 높은 경도분포값을 나타내었으며 그 이상 장시간 처리하면 오히려 경도가 감소하는 경향을 나타낸다. 그리고 침붕층은 20% HCl, 20% H₂SO₄용액에서는 뛰어난 내식성을 가지나, 20% HNO₃용액에 대해서는 상대적으로 내식성이 떨어졌다. 그리고 내고온산화성은 대기중 800˚C까지는 침붕처리한 시편이 우수했으나 900˚C부터는 오히려 감소했다. To improve the surface hardness of the 0.1V steel, by Boronizing Treatment, We got boride layer showing high hardness, Hv=1500∼2000. A parabola relationship was appeared between boride layer thickness and treatment time, and apparent activation energy to form the boride layer 94kJ/mol. Moreover, We obtained the most high hardness distribution value when had the boronizing treatment for 3 hours at 900˚C. On the contrary, If we did boronizing treatment above 3 hours, the hardness appeared decreasing tendency. The boride layer had a good corrosion resistance at a solution of 20% HCl and 20% H₂SO₄, but correlatively the corrosion resistance of the boride layer was declined at a solution of 20% HNO₃. And the boronized specimen had a good high temperature oxidation resistance until 800˚C in the atmosphere but the high temperature oxidation resistance go down above 900˚C.

α-Amylase Inhibitor 생산균 Streptomyces sp. AI-118의 분리 및 동정

권태종,서동진 建國大學校 附設 産業技術硏究所 1992 논문집 Vol.17 No.-

a-amylase의 효소작용을 저해하는 물질을 생산하는 균주를 토양에서 분리, 동정하였으며 저해물질 생산의 최적 조건을 검토하였다. 본균을 방선균 종정법에 따라 결과 새로운 균주로 판명되어 Streptomyces sp. AI-118이라고 명명하였다. 본 균주는 탄소원으로 corn starch 3.0%, 질소원으로 soy bean meal 1.0%, 무기염으로 NaCI 0.05%, MnSO₄·4H₂O 0.0001%, CuSO₄·5H₂O 0.0001%를 사용한 배지에서 initial pH 6.0, 30℃ 그리고 배양 72시간일 때 최대의 저해물질을 생산하였다. A microorganism, strain AI-118, capable of producing a new a-amylase inhibitor in culture broth was isolated from soil and identified as Streptomyces sp. on the morphological, cultural and physiological characteristics. The preferable medium composition has been determined to be as follows:3.0% corn starch, 1.0% soy bean meal, 0.05% NaCl, 0.05% K₂HPO₄, 0.0001%MnSO₄· 4H₂O and 0.0001% CuSO₄·5H₂O(pH6.0). The inhibitor was maximally produced after 60-80hr cultivation in a jar fermentor at 30℃.

마이크로 그루브 가공의 특성 평가

권동희,박진효,김정석,김병민,정융호,강명창 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

As demands for micro parts are on the increase in recent industries such as aerospace, biomedical, electronics, environment, information technology and display, the need for manufacturing such parts is also increasing. Major methods of manufacturing micro parts are based on semiconductor process technology such as lithography and etching and non-traditional machining using lasers, ultrasonic, ion-beams or electrical discharge. However, these methods require lots of time, workpiece materials are limited, and such methods are only applicable to the machining of two-dimensional shapes. Therefore, mechanical machining methods are required for the manufacturing of micro parts with complex shapes. This paper presents an investigation on the characteristics for micro groove machining by using the ultrahigh-speed air turbine spindle, and verifies the properties of mechanical method in fabricating molds for micro barrier ribs. As a result, the optimal machining condition could be found from the investigation of surface roughness according to the kinds of burr shapes in the fabricating of iron mold by using micro endmill.

남부지역에서의 양파 수확, 저장 및 유통실태

권병선,이을태,오용비,정동희,이조진 順天大學校 師範大學 附屬 科學敎育硏究所 1996 科學과 敎育 Vol.4 No.-

This study was carried out to find marketing, storage and harvest of onion in southern parts of Korea from Jan. 1994 to Apr. 1994. Early maturing cultivar harvest between 10th and 20th of May but late maturing cultivar harvest between 10th and 20th of June, this period was busy farming season with a shortage of labor. Early maturing cultivar was send out good directly but late maturing cultivar was send out good after shortage the simple store house with the period 7-9 month, and professional seed production farmer are not in here. We hope that this report stimulates research to investigate for the establishment of not only harvesting practices such as varietal improvement, machanical harvesting and disease resistant variety for the storage.

후방복사된 초음파를 이용한 12Cr강 부식 피로특성 평가

권성덕,윤석수,송성진,배동호 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.5

화력발전 플랜트의 터빈 블레이드(blade) 재료인 12Cr 합금강의 고속 열화 시편에 대한 레일리(Rayleigh) 표면탄성파의 산란과 속도의 주파수 의존특성을 액체/고체 경계 면에서 표면파의 발생기구에 의해 나타나는 후방복사 초음파 세기의 입사각 의존성으로 간접 평가하고 부식피로 특성과 비교 분석하였다. 후방복사 현상이 발생하는 입사각 폭은 부식온도와 반비례하였으며 이는 효과적 부식층의 두께 증가로 설명되었다. 이 프로파일의 폭은 피로시험에서 균열성장 관계식인 파리스(Paris) 법칙의 지수 m과 선형적으로 반비례하여 열화시편의 부식 피로 특성의 비파괴적 평가에 있어 후방복사된 초음파를 이용한 기술이 매우 유용함을 보여주었다. The corrosion-fatigue characteristics of the 12Cr steel, which is widely used in fossil power plants as a turbine blade material, are evaluated nondestructively by use of the Rayleigh surface wave. In this study, the frequency dependency of the Rayleigh surface wave is investigated indirectly by measuring the angular dependency of the backward radiation of the incident ultrasonic wave in the aged specimens, and then compared to the corrosion-fatigue characteristics. The width of the backward radiation profile decreases as the increase of the aging temperature, which seems to result from the increase of the effective degrading layer thickness. This parameter also shows an inversely proportionality to the exponent, m, in the Paris law which predicts the crack size increasement due to fatigue. The result observed in this study demonstrates high potential of the backward radiated ultrasound as a tool for the nondestructive evaluation of the corrosion-fatigue characteristics of the aged materials.

취학전 아동의 체력 실태와 평가

권영옥,김동권,민춘기,이용인,전종귀,진윤수,홍성표 忠南大學校體育科學硏究所 1995 體育科學硏究誌 Vol.13 No.1

The purpose of this study was analyze children's Physical Fitness and basic rate by observing the change in the heart rate of the 1230 children of five of six years of age. Following conclusions were obtained The muscular strength was relatively low according to places. And the muscular strength of boys was higher than that of girls. The flexibility of girls was higher than that of boys according to places and sexes. The muscular endurance, power, balance and agility of boys were higher than those of girls according to places and sexes. Thus the development of physical fitness was improved with their ages, the physical fitness for physique seemed rather low. So the programs of physical plays for children's physical fitness ought to be developed and physical play showed to be done at kindergarten school.