http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Gi Heon Ha(하기헌),Hoang Vu Phan(판호앙부),Hoon Cheol Park(박훈철) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
The pulley-wire mechanism used in the flapping mechanism of the KUBeetle-S, which is a tailless insect-like flapping wing micro air vehicle(FW-MAV), has been replaced with a rack-pinion mechanism for relatively easier and simpler fabrication. We first have determined the gear ratio of the new mechanism, so that it can demonstrate a similar performance to that of the previous KUBeetle. The gear ratio of 30:1 is chosen after comparing the thrusts and lift-to-power ratios of the flapping mechanisms with various gear ratios. In addition, the attitude control mechanism for stable attitude control and maneuverability of the robot is designed based on the same Stroke-Plane-Change(SPC) mechanism used in the KUBeetle-S. The 17.5 g robot fabricated by integrating the modified flapping-wing mechanism and the attitude control mechanism is named KUBeetle-RP. In order to guarantee flight stability, through several flight tests, we have adjusted the gain value of the attitude control system based on the PD control. Finally, KUBeetle-RP demonstrates a stable hovering flight for about 7 minutes.
Plastic-Based Organic Thin-Film Transistors with Thermally Cured Polymeric Gate Dielectrics
Gi Heon Kim,Chul Am Kim,In-Kyu You,Kyu-Ha Baek,Kyung Soo Suh,Seong Deok Ahn,Seong Youl Kang,윤성민 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.3
In this investigation, we synthesized thermally curable polymers by mixing poly(vinyl phenol) (PVP) and a thermal-crosslinking agent (a methylated melamine-formaldehyde, MMF). These polymeric insulating films exhibit good chemical, physical, and electrical properties as dielectrics. Their insulating and dielectric properties depend on the MMF concentration. We fabricated plastic-based organic thin-film transistors (OTFTs) with these dielectric layers to investigate the relationship between the performance of the OTFT and the electrical/chemical properties of these insulating films. The OTFT showed good electrical performance; the field-effect mobility was 1.1 cm2V.1s.1. A dielectric layer with a relatively low dielectric constant was found to give a higher field-effect mobility.
송인호,Heon-Kyun Ha,Sang-Gi Choi,Byeong Geon Jeon,Min Jung Kim,Kyu Joo Park 대한대장항문학회 2012 Annals of Coloproctolgy Vol.28 No.6
Purpose: The purpose of this study was to evaluate the overall rate and risk factors for the development of an incisional hernia and a parastomal hernia after colorectal surgery. Methods: The study cohort consisted of 795 consecutive patients who underwent open colorectal surgery between 2005and 2007 by a single surgeon. A retrospective analysis of prospectively collected data was performed. Results: The overall incidence of incisional hernias was 2% (14/690). This study revealed that the cumulative incidences of incisional hernia were 1% at 12 months and 3% after 36 months. Eighty-six percent of all incisional hernias developed within 3 years after a colectomy. The overall rate of parastomal hernias in patients with a stoma was 6.7% (7/105). The incidence of parastomal hernias was significantly higher in the colostomy group than in the ileostomy group (11.9% vs. 0%; P = 0.007). Obesity, abdominal aortic aneurysm, American Society of Anesthesiologists score, serum albumin level, emergency surgery and postoperative ileus did not influence the incidence of incisional or parastomal hernias. However, the multivariate analysis revealed that female gender and wound infection were significant risk factors for the development of incisional hernias female: P = 0.009, wound infection: P = 0.041). There were no significant factors related to the development of parastomal hernias. Conclusion: Our results indicate that most incisional hernias develop within 3 years after a colectomy. Female gender and wound infection were risk factors for the development of an incisional hernia after colorectal surgery. In contrast, no significant factors were found to be associated with the development of a parastomal hernia.