CO_2 레이저빔을 이용한 TFT-LCD 도광판의 패턴 제작에 관한 연구

김경동,백창일,송철기,안성훈 경상대학교 생산기술연구소 2002 工學硏究院論文集 Vol.2 No.-

A light guide panel is an element of the LCD backlight module that is often used for the display of compact electronic devices. In this study, a laser marking system is proposed to fabricate light guide panel, which can replace other manufacturing methods such as silk printing, stamping, or v-cutting methods. The objective of this research is to evaluate the process parameters of the laser marking system. Light guide patterns were marked with a 50W CO_2 laser(CW) to understand the effects of average power and scanning speed on the geometry and quality of groove pattern. The width of the fabricated grooves increases with increasing laser power and decreasing scan speed. In order to analyze surface characteristics and optical properties(luminance, uniformity), SEM photography and BM7(luminance measuring system) were used. As a result, the optimal conditions of the process parameters that provide high luminance was obtained.

한국철학 : 최한기(崔漢綺)의 이상사회론에 대한 고찰 -『대학(大學)』 팔조목(八條目) 중 수신(修身),제가(齊家),치국(治國),평천하(平天下)를 중심으로-

백준철 ( Jun Chul Beak ) 한국철학사연구회 2014 한국 철학논집 Vol.0 No.40

儒學思想의 基底를 이루고 있는 것은 經學이다. 經學이란, 해석자가 경전이라는 권위에 기대어 자신의 시대적·사회적·사상적 입장을 투영하여 재해석하여 자신의 이상과 신념을 표현하는 학문이라고 할 수 있다. 우리나라에 儒敎經典이 유입된 후 조선시대에 이르러서는 주자학적 경학이 그 주류를 형성하여 17세기까지 지속되었는데, 17세기 말부터는 주자학적 이념체계에 대한 반성과 탐색이 시도되면서 탈주자학적 경전 해석 경향이 나타나게 되었다. 이 가운데에서 필자는 運化라는 세계관을 바탕으로 하여 사상 체계를 구축한 혜강 최한기(1803∼1877)에 대해서 주목하게 되었다. 최한기의 학문을 학계에서는 흔히 ``탈경학``이라고 표현하지만, 그가 경학에 대해서 일정한 견해를 가지고 있었다는 사실은 그의 저서 『通經』과 기타 經典에 대한 언급에서 증명된다. 그러나 그동안의 연구에서 대부분의 선행 연구자들은 최한기의 철학에 미친 經典의 영향에 대해서는 간과하는 측면이 있다. 이 논문에서는 최한기가 『大學』의 八條目 중 修身·齊家·治國·平天下에 대해서 논술한 부분을 참고하여 그의 이상사회론에 대해 분석한다. 현존하는 그의 저서에서 『大學』 조목에 대한 부분을 보면 그는 三綱領보다는 八條目을 주로 언급하였고, 그 중에서 특히 修身·齊家·治國·平天下에 대해서 주로 언급하였다. 이 부분은 최한기 이전의 조선 학자들과 다른 독창적인 해석으로써 주목할 만 하다. 그러나 그의 『通經』은 序文 이외에 현존하지 않으므로, 그의 저술 가운데에서 특히 『神氣通』, 『推測錄』, 『氣學』, 『人政』에서 그의 修身·齊家·治國·平天下 관련 논술을 三等運化의 구조를 차용하여 분석하고, 그의 이상사회론의 근거를 찾아보았다. Chinese classical studies underlie the core elements of Confucianism. Chinese classical studies refer to a branch of academic studies based on which scholars reflect and reinterpret their own social and academic views in their own times based on the authority of the classical canons and thereby express their ideals and theories. Since the introduction of Chinese classical studies in the nation, the studies had focused much on Neo-Confucianism until the 17th century during the Joseon dynasty. After the late 17th century, however, there appeared self-reflections on and a demand for new exploration of Zhu Xi`s thoughts, and Chinese classical studies in Joseon began to gradually break away from the orthodox thoughts of Zhu Xi. As it is widely recognized that the new trend of classical thoughts, however, had been not been completely deviated themselves from Zhu Xi`s world views, it would be worthwhile to focus on the theory of Hyegang Choi Han-ki (1803∼1877) who left books based on his world view of unhwa (運化), or the activities of physical forces. Though the studies of Choi Han-ki have been widely interpreted as the post-Chinese classical studies, he had his own views on the subject of Chinese classical studies, which was well manifested in his book Tonggyeong (The Complete Analysis of Chinese Classics). Nevertheless, the previous studies in Korea has largely neglected the impact of Chinese classics on his philosophy. This dissertation has examined Choi Han-ki`s utopian theory on his own explanations of Daxue (Great Learning), one of the key cannons of Confucianism.

다발성 뇌수막종 1례

백승찬,김오룡,지용철,조수호,임좌혁,최병연,배장호 영남대학교 의과대학 1988 Yeungnam University Journal of Medicine Vol.5 No.2

본 영남대학교 의과대학 신경외과학 교실에서는 다발성 뇌수막종 1예를 수술 치험하였기에 문헌고찰과 함께 보고하는 바이다. The incidence of multiple meningiomas found prior to the introduction of CT was 1∼2%, the incidence since the introduction of CT was 8.9%. The authous report a case of multiple meningiomas without evidence of von Recklinghausen's disease. The possible presence of more than 1 tumor in an patient with an intracranial meningiomas must always be kept in mind. The pathogenetic factors related to true multiple meningiomas is unknown. We report a patient with multiple meningiomas with was confirmed by operation.

DNS Resolution with Renewal Using Piggyback

Jang, Beak-Cheol,Lee, Dong-Man,Chon, Kil-Nam,Kim, Hyun-Chul The Korea Institute of Information and Commucation 2009 Journal of communications and networks Vol.11 No.4

Domain name system (DNS) is a primary identification mechanism for Internet applications. However, DNS resolutions often take an unbearably long time, and this could seriously impair the consistency of the service quality of Internet applications based on DNS such as World Wide Web. Several approaches reduce DNS resolution time by proactively refreshing expired cached records or prefetching available records beforehand, but these approaches have an inherent problem in that they cause additional DNS traffic. In this paper, we propose a DNS resolution time reduction scheme, named renewal using piggyback (RUP), which refreshes expired cached records by piggybacking them onto solicited DNS queries instead of by issuing additional DNS queries. This method decreases both DNS resolution time and DNS traffic since it reduces the number of queries generated to handle a given DNS resolution without generating additional DNS messages. Simulation results based on two large independent DNS traces show that our proposed approach much reduces not only the DNS resolution time but also the DNS traffic.

Performance Impact of Large File Transfer on Web Proxy Caching: A Case Study in a High Bandwidth Campus Network Environment

Kim, Hyun-Chul,Lee, Dong-Man,Chon, Kil-Nam,Jang, Beak-Cheol,Kwon, Tae-Kyoung,Choi, Yang-Hee The Korea Institute of Information and Commucation 2010 Journal of communications and networks Vol.12 No.1

Since large objects consume substantial resources, web proxy caching incurs a fundamental trade-off between performance (i.e., hit-ratio and latency) and overhead (i.e., resource usage), in terms of caching and relaying large objects to users. This paper investigates how and to what extent the current dedicated-server based web proxy caching scheme is affected by large file transfers in a high bandwidth campus network environment. We use a series of trace-based performance analyses and profiling of various resource components in our experimental squid proxy cache server. Large file transfers often overwhelm our cache server. This causes a bottleneck in a web network, by saturating the network bandwidth of the cache server. Due to the requests for large objects, response times required for delivery of concurrently requested small objects increase, by a factor as high as a few million, in the worst cases. We argue that this cache bandwidth bottleneck problem is due to the fundamental limitations of the current centralized web proxy caching model that scales poorly when there are a limited amount of dedicated resources. This is a serious threat to the viability of the current web proxy caching model, particularly in a high bandwidth access network, since it leads to sporadic disconnections of the downstream access network from the global web network. We propose a peer-to-peer cooperative web caching scheme to address the cache bandwidth bottleneck problem. We show that it performs the task of caching and delivery of large objects in an efficient and cost-effective manner, without generating significant overheads for participating peers.

Mössbauer studies of Zn0.05Fe2.95O4 nanoparticles

Kim Sung Beak,Choi Hyunkyung,Kim Chul Sung 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.10

Nanoparticles of spinel ferrite (Zn0.05Fe2.95O4) were prepared using the process of high- temperature thermal decomposition (HTTD) and were treated with an Ar plasma for 30 min. The crystal structure was found to be cubic spinel with space group (Fd-3m). The lattice constants of Zn0.05Fe2.95O4 before and after the plasma treatment were found to be 8.3862 and 8.3853 Å, respectively. The saturation magnetization value increased from 69.1 to 73.5 emu/g after the plasma treatment of the Zn0.05Fe2.95O4 nanoparticles. The Mössbauer spectra before and after the plasma treatment of Zn0.05Fe2.95O4 were analyzed at 4.2 K using four sextets. As the temperature was increased, the lines of the Mössbauer spectra broadened due to a fluctuation in the anisotropic hyperfine field. The Mössbauer spectra were found to have the same anisotropic field fluctuation of +H (P+ = 0.5) and -H (P- = 0.5). The relaxation frequency factor, f, was also calculated from the Mössbauer spectra.

피스톤 경량화를 위한 금속복합소재 개발과 기초 특성 평가

백승주(Seungju Beak),이정구(Jungkoo Lee),김지윤(Jiyun Kim),이원혁(Won Rhee),임규철(Gyu Chul Im),이기형(Kihyung Lee) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6

퇴행성 슬관절염에서 히야루론산의 효과

이동철,백승희,손욱진,신규식,한재형 대한슬관절학회 2002 대한슬관절학회지 Vol.14 No.2

목적: 퇴행성 슬관절염에서 골관절염의 정도, 비만도, 대퇴 경골 정렬에 따른 히야루론산의 임상효과를 알아보고자 하였다. 대상 및 방법: 퇴행성 슬관절염 환자 73명을 대상으로 53명에게는 히야루론산(히야루론산 Purpose: The Purpose was to evaulate the efficacy of sodium hyaluronate (HA) according to the degree of osteoarthritis, body mass index and tibiofemoral alignment. Materials and Methods: 53 of 73 patients who had osteoarthritis of the knee were underwent intraarticular injection weekly for 5 weekly for 5 weeks with hyaluronic acid (HA, hyruan®, MW:1MDa) and 20 of 73 ticular injection weekly for 5 weeks with placebo (normal saline). The patients were followed for 27 weeks. Results were evaluated with wvisual analogue scale for pain, Lequesne algofunctional index for functional severity and Tegner activity score for activity. The degree of severity of osteoarthrtis of knee was stratified by Kellgren classification. Results: In the group treated with HA, the patients classified as Kellgren classificanton Ⅱ and Ⅲ showed much better improvement in efficacy for pain, function and activity compared with group Ⅳ. In the femorotibial alignment, neutral and valgus alignment group showed better results that varus group. There is no statistical significance in the knee pain and function between normal and overweight group. Best symptomatic improvement according to the subjective symptom revealed at 3 week in 25 patients (47.2%). Placebo treated patients had slight pain and improved functional perfomance but less effect in compared with HA treated patients. Conclusion: Intraarticular administration of HA relieve the symptom of osteoarthritis and improve the function of knee joint. Especially, the patients classified with Kellgren classification Ⅱ, Ⅲ and valgus, neutral tibiofemoral alignmen groups showed much better improvement than grade Ⅳ and varus group.

균열암반에서 방사성 붕괴사슬과 콜로이드를 동반한 방사성 핵종의 이동에 관한 이론적 연구

박진백(Jin Beak Park),황용수(Yong Soo Hwang),강철형(Chul Hyung Kang) 한국암반공학회 2003 터널과지하공간 Vol.13 No.1

Catechin and Caffeine Concentration Variations in Jeju Green Tea Varieties Harvested Over a Seven-Month Period

Song, Kwan-Jeong,Beak, Dong-Chul,Kim, You-Wang,Kim, Young-Geol,Lee, Min-Seok,Lee, Sam-Pin,Kim, Chan-Shick The Korean Society of Food Science and Nutrition 2010 Preventive Nutrition and Food Science Vol.15 No.3

Caffeine and catechins from the Yabukita, Yutakamidori, Saemidori, Okumidori, and Fushun varieties of tea leaves picked during different harvesting seasons from April to October were evaluated using HPLC. Total content of catechins increased greatly with the later harvesting time of tea leaves (i.e., picking the leaves in September versus in April) and decreased slightly after September. Yabukita tea leaves picked in August contained 43.1 mg% catechins including EGC, EC, ECG, and EGCG, with the ECGC levels constituting greater than 50% of those four compounds. Yutakamidori and Okumidori varieties picked in September contained the highest catechin values, at 43.6 mg% and 31.0 mg%, respectively. Fushun and Saemidori varieties contained lower catechin concentrations of 14.5 mg% (July) and 11.7 mg% (August) compared to other varieties. The EGCG levels gradually decreased in the late harvesting season, while levels of the other catechins, EC, EGC, and ECG, gradually increased. All varieties of green tea showed a gradual decrease in caffeine content toward the end of our harvesting efforts in October, with levels of 58~68 mg% in April and 28~57 mg% in October. Yabukita, Saemidori, and Okumidori varieties reached their highest caffeine levels in late spring/early summer, with Yabukita and Okumidori varieties reaching a high of 73.4% and 63.5% caffeine, respectively, in May, and Saemidori at 64.0% in June. In particular, Fushun still contained high caffeine of 66.8 mg% (September) during the late harvesting season.