선박 소음진동해석 프로그램의 연구개발 및 활용 현황

홍석윤 한국소음진동공학회 2007 한국소음진동공학회 세미나 Vol.2007 No.6

음향공진과 맥진동 현상을 이용한 폐수처리용 산기관 개발 및 성능시험

홍석윤,문종덕,Hong, Suk-Yoon,Moon, Jong-Duck 한국음향학회 1996 韓國音響學會誌 Vol.15 No.6

음파와 진동에너지를 활용하는 음파기술의 응용 연구분야로 음향공진 및 맥진동 현상을 이용하여 기액상에서 산소절달효율을 극대화 할 수 있는 폐수처리용 음향공진 산기관의 개념을 제안하였으며 원리와 성능시험을 수행하였다. 또한 저압용 헬름흘쯔 공진기, 실린더형 및 고리형 반사공진기 그리고 복합 공진시스템의 설계개념과 원리를 구현하였다. 물질전달 과정을 촉진하는 음향공진 에너지는 산소전달효율을 높여주며, 노즐에서 분출하는 공기 제트의 불평형에 의해 발생하는 주기적인 맥진동 현상은 미세한 공기방울을 만들어 내는데, 이 두가지 원리가 가장 잘 적용되는 고리형 반사공진기(AJR)의 성능이 가장 우수한 것으로 평가되었으며 기존의 산기관 보다도 $20{\sim}30%$ 정도 높은 효율을 실험으로 확인하였다. Using the acoustic resonances and oscillatory pulsations considered as the branch of wave technologies, the concept of the acoustic resonance diffusers for waste water treatment which maximize the oxygen transfer efficiency in gas-liquid two phase medium have been proposed, and studies for the principles and performance tests were accomplished. Besides, the design concepts for the low pressure Helmholtz resonator, cylinder and annular type reflection resonator and combined type resonance system have been implemented. The acoustic resonance energy which can speed up the mass transfer process increase the oxygen transfer efficiency, and periodic pulsations generated from the instability of air jet from nozzle make very small air bubbles. Then, the annular type jet resonator(AJR) applying these two principles successfully was evalulated as the most promising device and also the efficiency showing $20{\sim}30%$ better than conventional diffusers has been verified experimentally.

전방부 분절골절단술로 인한 의원성 외상 치아의 교정적 이동

홍석윤,김영호,채화성 대한치과교정학회 2019 대한치과교정학회 임상저널 Vol.9 No.3

When extraction treatment is planned in patients with lower three incisors, three premolars extraction is widely accepted. In this case report, moving traumatized teeth to close the orthodontic residual space after anterior segmental ssteotomy (ASO) will be presented. The patient underwent ASO and was referred for orthodontic treatment after three months. #14, 24, 34 was extracted, and a surgical attempt to separate #43 and #44 was noted. Upon clinical exam, teeth discoloration of #23, 33, 44 was evident. In addition, radiographs, including CT revealed that the surgical line was quite approximated to the root surface, especially to #44. No symptoms were noted. Possibility of PDL damage was suspected, regarding ankylosis and trauma. Although panorama and periapical X-rays showed poor prognosis of those teeth, CT sectioning indicated no obvious root damage. Furthermore, the patient insisted that her lips were more retracted than she expected. Thus, molars protraction to close the residual space was necessary. Clinical examination also demonstrated of 3 mm anterior open bite, lower three incisors, and residual space of 5 mm in the upper and 2 mm in the lower arch. Biomechanically, it is hard to perform molars protraction while closing anterior open bite. Maxillary incisors brackets were positioned upside-down (0.022-inch slot MBT, -17°) to increase upper incisal show and also to consider further maxillary full-arch protraction due to the patient complaint. To achieve molars protraction and intrusion simultaneously, protraction TPA with high positioned solder hooks were designed and delivered. TPA protraction was attempted first to test the possibility of ankylosis before full treatment. Superimposition revealed that the molars were successfully intruded and protracted, which contributed to the mandibular plane closing effect. A successful substitution for #43 to #42 and acceptable occlusion was obtained. Careful examination of CT sectioning helps orthodontic treatment of surgically traumatized teeth. Diagnostic molar protraction followed by active intrusion helps to achieve acceptable outcomes.

관통보와 평판의 연결 구조물에 대한 진동인텐시티 해석

홍석윤,강연식 한국음향학회 2002 韓國音響學會誌 Vol.21 No.1

본 논문에서는 중고주파영역에서의 진동해석기법인 파워흐름해석 법을 보와 평판이 연성된 구조물에 적용하기 위하여 무한보가 무한평판을 수직으로 투과하는 구조물에서의 파워투과반사계수를 파동전달법을 이용하여 구하였다. 이러한 파워투과반사계수를 실제 구조물에 적용하기 위해서는 파워흐름유한요소법으로의 활용이 필요하다. 이를 위해 본 논문에서는 파워투과반사계수를 이용하여 보 평판구조물을 위한 연결요소행렬식을 정립하였으며, 또한 보와 평판요소를 각각 해석할 수 있는 파워흐름유한요소해석 프로그램을 구성하고, 여기에 정립된 보와 평판간의 연결요소 행렬식을 대입하여 보와 평판이 연성된 구조물까지 해석이 가능한 프로그램으로 개발하였다. 이 프로그램을 이용하여 이상화한 선박의 선미부 구조물을 해석한 결과, 선박구조물에서 진동에너지분포를 구할 수 있었고, 진동 인텐시티를 통하여 구조물에서의 파워전달경로를 예측할 수 있었다. The transmission of vibration energy through beam-plate junctions in vibration intensity analysis called power new analysis (PFA) has been studied. PFA is an analytic tool for the prediction of frequency averaged vibration response of built-up structures at medium to high frequency ranges. The power transmission and reflection coefficients between the semi-infinite beam and plate are estimated using the wave transmission approach. For the application of the power coefficients to practical complex structures, the numerical methods, such as finite element method are needed to be adapted to the power flow governing equation. To solve the discontinuity of energy density at the joint, joint matrix is developed using energy flow coupling relationships at the beam-plate joint. Using the joint matrix developed in this paper, an idealized ship stem part is modeled with finite element program, and vibration energy density and intensity are calculated.

(주) 에이브이티를 찾아서

홍석윤,이영제 한국소음진동공학회 2009 소음 진동 Vol.19 No.4

공사 참여사에 인센티브 필요 : ABC

홍석윤 한국언론진흥재단 1998 新聞과 放送 Vol.1998 No.1

제어오차계의 가중치를 이용한 차실내 능동소음제어 시스템 연구

홍석윤,허현무 한국소음진동공학회 1996 소음 진동 Vol.6 No.6

The active noise cancellation system showing the effective convergence and stability has been studied by simplifying the controller structures using the weighting factors of control error path to the multi-channel filtered-x LMS algorithm which needs a lot of calculations and the performance has been verified experimentally. Besides, to implement the system performance in a vehicle cabin, experimental work for selecting the suitable numbers and positions of the microphones and speakers was accomplished. Effectively combining a TMS 320C 31 main processor conducting real number calculations and having various functions with other components, the purpose-built system board for active noise cancellation has been designed and with this board, car active noise cancellation system showing maximum stable 10dB noise reduction has been obtained at the car idling conditions above 3000rpm range.

언더필 재료를 사용하는 Cu/Low-K 플립 칩 패키지 공정에서 신뢰성 향상 연구

홍석윤,진세민,이재원,조성환,도재천,이해영,Hong, Seok-Yoon,Jin, Se-Min,Yi, Jae-Won,Cho, Seong-Hwan,Doh, Jae-Cheon,Lee, Hai-Young 한국마이크로전자및패키징학회 2011 마이크로전자 및 패키징학회지 Vol.18 No.4

현대 전자 산업에서Cu/Low-K공정의 도입을 통해 반도체 칩의 소형화 및 전기적 성능 향상이 가능해졌으나, Cu/Low-K는 기존의 반도체 제조 공정에 사용된 물질에 비해 물리적으로 매우 취약해진 단점을 가지고 있어 칩 제조 공정 과 패키지 공정에서 많은 문제를 유발하고 있다. 특히, 온도 사이클 후, Cu 층과 Low-K 유전층 사이의 박리현상은 주요 불량 현상의 하나이다. Cu/Low-K층은 플립 칩 패드의 상부에 위치하기 때문에 플립 칩이 받는 스트레스가 직접적으로 Cu/Low-K층에 영향을 주고 있다. 이런 문제를 해결하기 위한 언더필 공정이나 언더필 물질의 개선이 필요하게 되었고 특히, 플립 칩에 대한 스트레스를 줄이고 솔더 범프를 보호하기 위한 언더필의 선택이 중요하게 되었다. 90 nm Cu/Low-K 플립 칩 패키지의 온도 사이클 후 발생한 박리 문제를 적합한 언더필 선택을 통해 해결하였다. The size reduction of the semiconductor chip and the improvement of the electrical performance have been enabled through the introduction of the Cu/Low-K process in modern electronic industries. However, Cu/Low-K has a disadvantage of the physical properties that is weaker than materials used for existing semiconductor manufacture process. It causes many problems in chip manufacturing and package processes. Especially, the delamination between the Cu layer and the low-K dielectric layer is a main defect after the temperature cycles. Since the Cu/Low-K layer is located on the top of the pad of the flip chip, the stress on the flip chip affects the Cu/Low-K layer directly. Therefore, it is needed to improve the underfill process or materials. Especially, it becomes very important to select the underfill to decrease the stress at the flip-chip and to protect the solder bump. We have solved the delamination problem in a 90 nm Cu/Low-K flip-chip package after the temperature cycle by selecting an appropriate underfill.

고부가가치 선박의 소음ㆍ진동 연구

홍석윤 한국소음진동공학회 2008 한국소음진동공학회 세미나 Vol.2008 No.5

전신 홍반성 낭창(Systemic lupus erythematosus) 환자에서의 발치 교정 치료 치험례

홍석윤,김상환,채 훈,김영호,채화성 대한치과교정학회 2017 대한치과교정학회 임상저널 Vol.7 No.2