에어로졸 열분해법에 의한 구형형광체 제조에 관한 연구

홍근영,유영길,유재수 중앙대학교 기술과학연구소 2000 기술과학연구소 논문집 Vol.30 No.-

현재 FED, PDP의 상용화를 위해 많은 연구가 진행중인데 그 중에서 형광체에서 요구되는 조건은 발광효율의 향상이다. 상용으로 이용되고 있는 형광물질은 대부분이 고상법을 이용하여 그 형상이 매우 불규칙적이고 입자의 형상 및 그 입도의 분포가 매우 불리한 것으로 분석되어지고 있다. 그러나 고상법에 비해 에어로졸 열분해법은 그 제조공정이 다른 제조공정에 비하여 간단하며 복합산화물을 쉽게 제조할 수 있다는 장점이 있다. 본 연구에서는 이와 같은 특성을 이용하여 발광효율을 증대시키고자 구형의 형상을 지닌 형광체를 제조할 수 있는 공정을 개발하고자 연구하였다. 여러 가지 형광물질중에서 전계방출 디스플레이로 응용이 가능한 Y_2O_3:Eu과 ZnGa_2O_4:Mn의 산화물계 구형형광체를 제조하여 Cathodeluminescence, Photoluminescence의 특성을 분석, 연구하였다. Much research on the phosphor are undergoing for the commercialization of field emission display. Luminous efficiency of phosphor still remains to be solved. Phosphor particles prepared by conventional method show irregular shape and is expected to be poor for screen performance. Thus, spherical particles as another alternative was considered with aerosol pyrolysis technique, which has been known for years. In the work, Y_2O_3:Eu as red, ZnGa_2O_4:Mn as green phosphor were prepared by aerosol pyrolysis for real FED application and their characteristics were evaluated with optical measurement tools such as cathodoluminescence, and photoluminescence.

일산화탄소 중독과 관련된 정신병적 증상 및 파킨슨 증상이 동반된 환자에서의 Aripiprazole 치료 1예

김태석,홍근영,배치운,백인호 대한정신약물학회 2005 대한정신약물학회지 Vol.16 No.2

A newer atypical antipsychotic, aripiprazole has been shown to be effective in the treatment of schizophrenia and other psychotic disorders. A 44-year-old woman who developed psychotic symptoms and parkinsonism a month after carbon monoxide poisoning and did not respond to other atypical antipsychotics, was successfully treated with aripiprazole. This case suggests that aripiprazole may be helpful to those developed psychotic symptoms and movement disorders associated with toxic brain injury such as carbon monoxide poisoning.

지보재 파괴를 고려한 터널 안전율의 수치해석적 산정 연구

유광호,박연준,홍근영,이현구,김재권,You, Kwang-Ho,Park, Yeon-Jun,Hong, Keun-Young,Lee, Hyun-Koo,Kim, Jea-Kwon 한국터널지하공간학회 2005 터널기술 Vol.7 No.1

터널의 경우 지보재의 파괴가 터널의 파괴를 유발할 수 있으므로 지보재의 파괴가 고려된 안전율을 산정하는 것이 중요하다. 기존의 연구에서는 지보재의 파괴를 고려한 터널의 안전율 산정에 있어서 보 (beam)요소로 모델링하여 지보재의 파괴를 지보재에 발생하는 휨 응력과 허용응력을 비교하여 파괴를 고려하였다. 본 연구에서는 2차원 해석이 수행되었으며, 지보재를 보 (탄성)요소와 연속체 (탄소성)요소로 나누어 모델링하였고, 암반등급, 측압계수, 숏크리트 두께, 록볼트의 영향, 굴착방법이 터널의 안전율에 미치는 영향을 분석하여 적정 지보재의 모델링 방법을 제시하였다. In a tunnel, failure of its supports can cause failure of the tunnel. Therefore it is important to estimate safety factor of the tunnel which the failure of its supports is taken into account. In previous studies, supports of tunnels were usually modelled as beam elements. The failure of the supports was decided by comparing the allowable stress and the calculated bending stresses inside the beam elements in estimating safety factor of the tunnel considering the failure of its supports. In this study, it is suggested how to model the supports properly. To this end, supports of a tunnel were modelled by both beam (elastic) elements and continuum (elasto-plastic) elements in two dimensional numerical analyses. Meanwhile, it was analyzed how rock mass class, coefficient of lateral pressure, shotcrete thickness, the existence of rock bolt, and excavation method had an effect on the safety factor of a tunnel.

기계 화학적 방법을 통한 Eu³⁺ 도핑된 (Y,Gd)BO₃ 형광체의 분말제조

원희섭,이완재,김제석,홍근영,이근재,좌용호,Won, Hee-Sub,Lee, Wan-Jae,Kim, Je-Seok,Hong, Gun-Young,Lee, Kun-Jae,Choa, Yong-Ho 한국분말야금학회 2008 한국분말재료학회지 (KPMI) Vol.15 No.2

The mechanochemical process were employed to prepare the red phosphors (Y,Gd)$BO_3:Eu^{3+}$. The main factors affecting particle size, particle distribution, and luminescent properties of the product were investigated in details. Particles sized around 200-600 nm are formed after intensive milling. The phosphors were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectrum. Results revealed that phosphors with different morphology, small particle size and high luminescence intensity could be obtained by mechanochemical process.

지보재 파괴를 고려한 터널의 안전율의 수치 해석적 산정연구

유광호,박연준,김재권,홍근영,이현구 사단법인 한국터널지하공간학회 2005 한국터널지하공간학회논문집 Vol.7 No.1

In a tunnel, failure of its supports can cause failure of the tunnel. Therefore it is important to estimate safety factor of the tunnel which the failure of its supports is taken into account. In previous studies, supports of tunnels were usually modelled as beam elements. The failure of the supports was decided by comparing the allowable stress and the calculated bending stresses inside the beam elements in estimating safety factor of the tunnel considering the failure of its supports. In this study, it is suggested how to model the supports properly. To this end, supports of a tunnel were modelled by both beam (elastic) elements and continuum (elasto-plastic) elements in two dimensional numerical analyses. Meanwhile, it was analyzed how rock mass class, coefficient of lateral pressure, shotcrete thickness, the existence of rock bolt, and excavation method had an effect on the safety factor of a tunnel. 터널의 경우 지보재의 파괴가 터널의 파괴를 유발할 수 있으므로 지보재의 파괴가 고려된 안전율을 산정하는 것이 중요하다. 기존의 연구에서는 지보재의 파괴를 고려한 터널의 안전율 산정에 있어서 보 (beam)요소로 모델링하여 지보재의 파괴를 지보재에 발생하는 휨 응력과 허용응력을 비교하여 파괴를 고려하였다. 본 연구에서는 2차원 해석이 수행되었으며, 지보재를 보 (탄성)요소와 연속체 (탄소성)요소로 나누어 모델링하였고, 암반등급, 측압계수, 숏크리트 두께, 록볼트의 영향, 굴착방법이 터널의 안전율에 미치는 영향을 분석하여 적정 지보재의 모델링 방법을 제시하였다.

근전도 패턴 인식 및 분류 기반 다자유도 전완 의수 개발

이슬아,최유나,양세동,홍근영,최영진 한국로봇학회 2019 로봇학회 논문지 Vol.14 No.3

This paper presents a multiple DoFs (degrees-of-freedom) prosthetic forearm and sEMG (surface electromyogram) pattern recognition and motion intent classification of forearm amputee. The developed prosthetic forearm has 9 DoFs hand and single-DoF wrist, and the socket is designed considering wearability. In addition, the pattern recognition based on sEMG is proposed for prosthetic control. Several experiments were conducted to substantiate the performance of the prosthetic forearm. First, the developed prosthetic forearm could perform various motions required for activity of daily living of forearm amputee. It was able to control according to shape and size of the object. Additionally, the amputee was able to perform ‘tying up shoe’ using the prosthetic forearm. Secondly, pattern recognition and classification experiments using the sEMG signals were performed to find out whether it could classify the motions according to the user’s intents. For this purpose, sEMG signals were applied to the multilayer perceptron (MLP) for training and testing. As a result, overall classification accuracy arrived at 99.6% for all participants, and all the postures showed more than 97% accuracy.

4-10 Hz 빛과 소리자극 후 단기기억력 및 자율신경심장기능의 변화 - 예비연구 -

이승환,김진환,박중규,이경욱,양대현,홍근영,채정호,Lee, Seung-Hwan,Kim, Jin-Hwan,Park, Joong-Kyu,Lee, Kyung-Uk,Yang, Dae-Hyun,Hong, Keun-Young,Chae, Jeong-Ho 대한수면의학회 2004 수면·정신생리 Vol.11 No.1

목 적 : 본 연구는 $4{\sim}10\;Hz$의 빛과 소리자극이 인체의 단기기억력 및 긴장이완에 어떠한 영향을 주는지 관찰하기 위한 예비연구로 시행되었다. 방법:총 10명의 대상을 무작위로 동기화된 파형의 빛과 소리를 가한 처치군(R 군)과 동기화되지 않은 무작위 파형의 빛과 소리를 가한 허위군(P 군)으로 분류하고, 하루 15분씩 5일간 빛과 소리 자극을 가하였다. 단기기억력을 측정하기위한 척도, 불안 척도 그리고 자율신경심장 기능 검사 등을 시행하였다. 2일간 휴식 후 R군과 P군을 교차하여 5일간 같은 실험을 반복하였다. 결 과:R군에서 빛과 소리자극 1회 적용 후 단기기억력의 유의미한 향상이 관찰되었다. 자율신경심장기능 검사에서는 R군에서 유의미한 이완 효과가 관찰되었다. 결 론:이 연구 $4{\sim}10\;Hz$의 빛과 소리자극이 단기기억 및 긴장이완과 연관됨을 암시한다. 향후 실험대상수를 늘려 예비연구결과를 확인함이 필요하다. Objectives: Sound and light (SL) stimulation has been used as a method to induce some useful mental states in the fields of psychology and psychiatry. It is believed that sound and light entrainment device (SLED) has some specific effects through synchronization of EEG in patients who use it. Theta frequency is believed to stimulate deep relaxation and short term memory processing. This study was conducted to evaluate if 4-10 Hz SL stimulation can induce relaxation and improve short term memory function. Methods: Ten medical students with no medical or psychiatric problems participated in this study. Subjects were randomly divided into two groups. One group was applied with real SLED was applied to one group (R group) and pseudo SLED to the other group (P group). The two groups were exposed to SL stimulation with SLED 15 minutes a day for 5 days, and after two days rest the two groups were switched over. The Korean Wechsler Adult Intelligence Scale (K-WAIS), Academic Motivation Tests (AMT), Test Anxiety Scale (TAS), Korean Auditory Verbal Learning Test (K-AVLT), and digit span were used to evaluate short term memory. Spielberger's State-Trait anxiety inventory and heart rate variability (HRV) test were used to evaluate degree of relaxation. Results: Compared with S group, R group showed a significant improvement in K-AVLT and digit span after a single application of SL stimulation. But 5-day long application did not reveal any differences between the two groups. A significant change in HRV was observed in 5-day long application of SL stimulation after being switched over to other SLED. Conclusion: This pilot study suggests that 4-10 Hz SL stimulation has some positive influences on short term memory and relaxation.

FlowNet을 활용한 텐세그리티 평면 기반 시촉각 센서 알고리즘 개선

윤영로(Youngro Yun),성민창(Minchang Sung),홍근영(Geun Young Hong),최영진(Youngjin Choi) 한국통신학회 2024 한국통신학회 학술대회논문집 Vol.2024 No.1