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초음파 음장해석 및 가시화를 통한 선형 위상차배열 트랜스듀서의 결함요소 검출 가능성 연구
최광윤,양정원,하강렬,김무준,김정순,이채봉,Choi, Kwang-Yoon,Yang, Jeong-Won,Ha, Kang-Lyeol,Kim, Moo-Joon,Kim, Jung-Soon,Lee, Chae-Bong 한국음향학회 2009 韓國音響學會誌 Vol.28 No.5
The ultrasonic pressure fields for the 3 MHz linear phased array transducer with sixteen piezoelectric elements of which one may not be operated by defect were simulated theoretically and measured experimentally using a visualization system of the Schlieren method. The simulation results for steering angles of $0^{\circ}$ and $30^{\circ}$ show that the side-lobe patterns of the transducer including a defective element is quite different from the transducer with all normal elements, and those patterns are in good agreement with the results of visualization. It is shown that the defective elements in a linear array transducer can be detected by comparison of the simulated and the visualized side-lobe patterns in two dimensional acoustic fields. 16개 압전요소로 구성된 3 MHz의 선형 위상차배열 초음파 트랜스듀서를 대상으로, 모든 압전요소가 정상일 때와 임의의 요소 하나가 결함으로 인해 동작하지 않을 때의 음장을 이론적으로 시뮬레이션하고, 슈리렌법에 따라 구축한 음장가시화장치를 이용하여 실험적으로 측정하였다. 조향각 $0^{\circ}$와 $30^{\circ}$일 때 각각에 대한 시뮬레이션의 결과, 임의의 압전요소가 결함으로 인해 동작하지 않을 때의 음장은 모든 요소가 정상적으로 동작할 때의 음장에 비해 부엽 패턴이 크게 다르게 나타나며, 그 형태는 가시화에 의한 측정결과와 잘 일치하였다. 따라서, 가시화 장치에 의해 측정된 2차원 음장에서의 부엽패턴을 시뮬레이션 결과와 비교 분석함으로써 선형 위상차배열 초음파 트랜스듀서의 결함요소 검출이 가능함을 알았다.
최광윤,안오성,이재희 한국항공우주학회 2014 한국항공우주학회 학술발표회 논문집 Vol.2014 No.4
항공산업의 발전은 군수부문과 병행하여 민수부분의 성장이 필요하며 우리나라 민수항공부분에서 빠르게 성장할 수 있는 분야는 기체구조물이다. 아직 민수완제기 시장이 없는 한국은 수출을 통하여 민수부분을 확대해야 한다. 경쟁이 더욱 치열해지는 국제 시장에서도 한국기업은 OEM 으로 부터 선호되는 supply base 으로 인식되고 있으며 이는 수출주도형 강한 전문 중소기업의 실적으로 입증이 되고있다. 이러한 모델이 영세했던 항공 중소기업에 새로운 가능성을 제공해주고 있으며 최근 중소기업의 직접수출이 증가 되는 상태이다. 따라서 전문 강소기업의 지속적인 발굴과 성장을 위한 정부의 정책적 지원 및 대/중소기업간의 균형 있는 역할 분담이 한국의 항공산업에 새로운 지평을 열어갈 것으로 기대된다. Aviation industry’s development needs growth from both military and commercial sectors. In Korean commercial sector, where no commercial airplane market is established, structure is known to have the fastest growing possibility and it can be achieved through export. In today’s ever competitive world market, Korean manufacturers are recognized as one of the most favorable supply base from the global OEM’s. This is proved from the performance of export driven strong SME’s. Such a new SME model lights up long waited possibilities for struggling SME’s in Korean aviation industry and they begin to increase export volume. Therefore balanced growth between large and medium size companies and proper role setup in their unique strength in the industry backed up with government policy support for continuous development of strong specialized SME’s will open up a new horizon in Korean aviation industry.
최광윤,배수환,정재동,김한철,최영화 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2
The purpose of this experiment is an experimental study on recycling of waste concrete and suggest a possibility of the Recycled Aggregate Concrete after establishing some kinds of experimental properties of concrete. Therefore, this study compared and investigated properties of natural aggregate concrete and recycled aggregate concrete by replacing the ratio of recycled aggregates under the absorptions, compressive strengths and chemical resistances. As the result, the compressive strength and the chemical resistance of Recycled Aggregate Concrete is lower than the natural aggregate concrete. If was concluded that the properties of the recycled aggregates and lower than natural aggregates.
의료용 초음파프로브의 압전소자 결함이 과도음장과 B-모드 영상에 미치는 영향
최광윤,하강렬,김무준,김정순,양정화,강관석,최민주,Choi, Kwang-Yoon,Ha, Kang-Lyeol,Kim, Moo-Joon,Kim, Jung-Soon,Yang, Jeong-Hwa,Kang, Gwan-Suk,Choi, Min-Joo 한국음향학회 2010 韓國音響學會誌 Vol.29 No.8
전체 192개의 압전소자 중 64개를 동시 구동하여 빔을 형성하는 중심주파수 3.5 MHz인 선형배열 의료용 초음파프로브를 대상으로 일부의 압전소자가 결함으로 인해 동작하지 않을 때의 과도음장 및 점 표적에 대한 초음파 B-모드 영상을 시뮬레이션하여 정상 초음파프로브의 것과 비교 분석하였다. 그 결과, 결함소자의 수가 한 개에서 네 개로 증가함에 따라 주엽이 만드는 음장의 최대음압준위 및 그 -3 dB 폭은 정상일 때에 비해 선형적으로 감소하나, 초점심도는 거의 변화가 없고, 부엽에 의한 음장의 음압준위 상승으로 인해 주엽과 부엽과의 음압 차이는 감소하는 경향을 보였다. 이와 같은 음압준위의 변화는 점 표적에 대한 B-모드 영상에 영향을 주어 표적의 좌우에 허상을 만들며, 축 방향의 공간분해능은 거의 일정하나 측 방향으로는 다소 감소하는 경향을 나타내었다. The ultrasonic transient fields and B-mode images of a point target which were simulated for a medical ultrasonic probe with a few defective piezo-elements were compared with those for a normal probe. The present study considered a 3.5 MHz linear array probe whose acoustic beam was formed by the 64 active elements of total 192 elements. The results showed that the maximum amplitude and -3 dB width of the acoustic fields by main-lobes decreased linearly as the defective element number increased from one to four. However, the depths of foci remained almost unchanged, and the pressure differences between main-lobes and side-lobes tended to decrease due to rise in pressures in side-lobes. Such changes in ultrasonic fields affected the B-mode images of point targets. So the artifacts were formed in the right and left side of the target, and the lateral spatial resolutions were decreased while the axial resolution was almost the same.
최광윤,김형종,박규정,김정호,한승조 조선대학교 전자정보통신연구소 1998 電子情報通信硏究所論文誌 Vol.1 No.1
We could design in this paper DES(Data Encryption Standard) algorithm which is regarded as a standard of encryption algorithm by VHDL(VHSIC Hardware Description Language) that is a system designable description language and synthesize a chip. Thus we could compute the size and speed of the hardware. We could execute in this paper 16-round iterations of a simple-round processor and design it to apply DES simple-round and implement it by Xilinx's FPGA. We could execute in this paper the simulation of DES which have designed simple-round iterative method by V-system. After synthesis of chip with using of Synopsys' ED-4, we could implement it to XC4025E with using of Xilinx's xdm. As a result of implementation, we could get the encryption and decryption speed of 133.3h4bps at the input clock frequency of 66MHz.
최광윤 ( Kwang Yun Choi ),김진강 ( Jin Gang Kim ),최문영 ( Moon Young Choi ),김미경 ( Mi Kyeong Kim ),이휘진 ( Hw Ijin Lee ),정유진 ( Yu Jin Jung ),이건희 ( Geon Hee Lee ),박미림 ( Mi Rim Park ),권민정 ( Min Jung Kwon ),양명은 ( M 대한통합의학회 2013 대한통합의학회지 Vol.1 No.1
The purpose of this study was to research the effects of exercise programs on genu varum persons` distance of between two legs. Method 40 persons who had genu varum were participated in this research. Randomly, among 30 were allocated in experimental group and others were allocated in control group. Stretching exercises, bend exercises and joint mobilization were applied to the experimental group for 6 weeks. For the statistical analysis, we used the independent t-test and the paired t-test. Result Stretching exercises, bend exercises and joint mobilization had statistically effects on distance of knees with gathering legs, distance of knees, distance of malleoluses, differences of distance from between malleoluses to between knees by GPS. Stretching exercises, bend exercises and joint mobilization had statistically effects on distance of knees, distance of malleoluses by ruler. Conclusion Therefore, this study showed that stretching exercises, bend exercises and joint mobilization influenced on the change of genu varum.
자극제 사용 미분쇄 플라이애쉬 모르타르의 강도증진에 관한 실험적 연구
배수환,최광윤,정재동 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)
The purpose of this study is for the active use of the fly ash, which is a by-product of the combustion pulverizes coal thermal power plants, it should be used to compensate for the lack of landfill and for conservation of energy as the supplementary cementitious material, and to prove its possibility as the related products of the cement. First of all, the ordinary fly ash is ground in a special method and its fineness is controlled from 4000cm²/g to 6000 cm²/g, then replaced it with the 20% to 80% of the cement mortar to test of the physical properties. The first experiment is about the slow development of the strength of the fly ash mortar in early ages, and improves its strength with the activator Na2SO4, using a large amount of fly ash. On the other hand, in case of adding activator with steam curing, it rather shows the decrease of strength. This is that it needs to consider the influence by high temperature.