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박세희,서현우,홍찬의 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.4
수종의 근관치료용 전기모터들의 반복사용과 시간에 따른 회전속도의 변화를 비교하여 근관치료용 전기모터의 회전 안정성을 평가하고자 하였다. 시간에 따라 변화하는 실제회전속도 및 전압과 전류를 측정하고, Student t-test를 통한 실제회전속도와, 반복측정분석을 통한 상관관계를 비교분석 하였다. 동일 종류의 전기모터들 사이의 모든 측정 결과들은 차이를 보이지 않았다. 모든 전기모터에서 반복사용과 시간의 흐름에 따른 회전속도의 변화는 차이를 보이지 않았다. 이상의 결과로, 본 실험에 사용된 모든 전기모터는 일정한 회전속도를 유지해야 하는 회전 안정성의 조건에 충족됨을 알 수 있으며, 반복사용과 시간에 따른 신뢰성 있는 회전속도와 안정적인 전압 및 전류의 유지가 가능하리라 생각된다. The purpose of this study was to evaluate a rotational stability of endodontic electronic motors by comparing the changes of rotational speed, depending on the number of usages and with/without static load. Twelve new endodontic electronic motors were used in this study. Non contact type digital tachometer was used for measuring the rotational speed of handpiece. True RMS Multimeter was used for measuring the voltages and the electric currents. All measurements were recorded every 10 seconds during 10 minutes and repeated 9 times. Five repetition was done per each electronic motor. To statistical analysis, student t-test, repeated measures and Scheffe's post-hoc tests were performed. In the same motor group, there was no significant difference in all measurements. In all groups, there was no significant difference in the amount of rotational speed changes depending on the number of usages and with/without static load. In the limitation of this study, the results showed that all kinds of endodontic electronic motors in this study had an established rotational stability. Therefore they could be safely used in root canal treatment with areliable maintenance of rotational speed, regardless of the number of usages and with/without load.
Novel broadband rectenna using printed monopole antenna and harmonic-suppressed stub filter
Hong, Tae-Ui,Oh, Kyoung-Min,Lee, Hyun-Wook,Nam, Hee,Yun, Tae-Soon,Lee, Dae-Sung,Hwang, Hak-In,Lee, Jong-Chul Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS - Vol.52 No.5
<P>This article reports a novel broadband rectifying antenna (rectenna) using the printed monopole antenna and the band-pass stub band-pass filter, which is designed in the microstrip line structure at 2.45 GHz for the wireless transmission of microwave power.We suggest a novel H-shape printed monopole antenna with size reduction of the radiator and the ground plane using surface current distribution, and a broadband stub band-pass filter with suppression of the second harmonic. The rectifying circuit with stub filter doesn't need additional area because it is fabricated on the ground plane, which is widened to acquire broadband characteristic of the monopole antenna. The RF-to-DC conversion efficiency of 66% is obtained by using a load resistor of 270 Ω at 2.45 GHz. Also, the conversion efficiency is maintained from 2 GHz to 3 GHz above 50%. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1194–1197, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25130</P>
Study of the Change of the Fatigue and the Visual Function before and after Viewing 2D and 3D Movies
Hyun-Goo Kang,Yung-San Jang,Ui-Ju Kim,Hyung-Ki Hong 대한시과학회 2016 대한시과학회지 Vol.18 No.2
목 적: 3D TV에서 2D 및 3D 영상 시청 전, 후 피로도와 시기능 변화를 피로도 설문지(Simulator Sickness Questionnaire)와 시기능 검사를 통해 비교 분석하였다. 방 법: 시기능의 이상이 없고 3D 입체영상 시청이 가능하며 양안 교정시력 0.8 이상인 23-29세(평균 연 령 25.3±1.6세)의 15명을 대상으로 하였다. 47인치 3D TV를 이용하여 2.5m 거리에서 30분 길이의 2D 및 3D 영화를 시청하였다. 시청 전, 후 피로도(5가지 범주, 28가지 항목의 설문) 및 시기능(원거리 및 근거리 사위, 폭주 근점, 상대조절력 등)을 검사하여 분석하였다. 결 과: 2D 및 3D 영상 시청 전, 후에 피로도 검사에서 2D 영상에서는 흐려 보임(p=0.019), 건조함 (p=0.023), 피로함(p=0.003)이 영상 시청 후 통계적으로 유의하게 증가하였고 3D영상에서는 피로함 (p=0.019), 어지러움(p=0.047)이 영상 시청 후 통계적으로 유의하게 증가하는 결과를 보였다. 총 28개의 항 목 중에 2D에서 3개 항목, 3D에서 2개 항목에서만 차이가 있었고, 그 점수 변화는 크지 않았다. 또한 시기 능 검사에서는 모든 항목에서 유의한 변화가 나타나지 않았다. 결 론: 2D 및 3D 영상 시청 전, 후에 피로감은 동일하게 측정되었다. 이는 3D 영상 전후 피로도가 증가했 다는 이전의 보고와 다른 결과이다. 이는 본 실험과 이전 보고들의 3D 시청 환경(3D 컨텐츠, 시청 거리, 3D 영상 표시 장치 등)이 다르기 때문으로 생각된다. 이는 또한 3D TV 시청 시 특정 조건에서는 피로감이 2D에 비교하여 심각하지 않을 수 있다는 것을 의미한다. Purpose: Change of the fatigue and the visual function before and after viewing 2D and 3D movie in 3D TV was analyzed using Simulator Sickness Questionnaire(SSQ) and the visual function test. Methods: 15 participants with the normal visual function, the normal stereopsis, the corrected visual acuity of higher than 0.8 and the age of range from 23 to 29 years (average age of 25.3±1.6 years) were selected. Participants watched 2D or 3D movies for 30 minutes on 3D TV of the diagonal size of 47 inch at the distance of 2.5m. Before and after watching movies, Fatigues (survey of 5 categories, 28 items) and the visual function such as phoria at the far and the near, near point of convergence and relative accommodation were measured and analyzed. Results: In the fatigue survey between before and after movies, scores of Burry (p=0.019), Dry eye (p=0.023) and Eye strain (p=0.003) increased statistically significantly in viewing 2D movie while scores of Eye strain (p=0.019) and Dizzy (p=0.047) increased statistically significantly in viewing 3D movie. Among 28 items, changes occurred only 3 items in 2D and 2 items in 3D and the amount of score change was not so large. And no statistically significant difference was measured in visual function test. Conclusions: Fatigues in viewing 2D and 3D movies was measured to be the same. This result contrasted with the previous report of increase of fatigue in viewing 3D. This may be attributed to the different 3D viewing environment such as 3D contents, viewing distance and 3D display. It also implies that the fatigue in viewing 3D TV under the specific condition would not be the serious compared with fatigue in viewing 2D.
이의현(Ui-hyun Lee),이철희(Chul-hee lee),홍창봉(Chang-bong Hong) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
In order to protect passengers in the vehicle collision, several applications are installed in vehicle for safety. Airbag is one of the applications installed in vehicles and its performance is evaluated by the distance between passengers and airbag itself. In this study, the distance between passengers and airbag is controlled by moving passenger seats with BLDC(Brushless DC) motor. The experimental result shows that the velocity of the seat meets the minimum requirement for this case. To validate its feasibility, the simulation of intergrated system of airbag and controlled passenger seat is conducted through LS-Dyna. In the simulation result, the impact on the passenger’s head is decreased. The actual dummy test will be conducted to validate this system.