고체 평면상에서 두 캐비테이션 버블의 상호 붕괴 충격력에 관한 실험적 연구

NYO ME THET NAING,정노택 한국해양환경·에너지학회 2022 한국해양환경·에너지학회지 Vol.25 No.2

It is to experimentally investigate the maximum impact force on the wall when two cavitation bubbles of different sizes are generated near the solid surface in a still fluid. Unlike bubble collapse in free filed, two bubbles generated near the wall have a rather complicated phenomenon because not only the interaction with the bubble-bubble but also the interaction with the bubble-wall surface occurs. Through the electric spark generator, three types of bubbles (radius 3.1 mm, 3.8 mm, and 4.5 mm) were used to compare with the impact force that appeared in the entire process from generation to collapse and the shape of the cor-responding bubble. Using two non-dimensional distance between the bubble and the bubble (η) and the distance from the wall (γ), the shape of the generated bubble was classified into five categories. It can be confirmed through the high-speed camera that the lower bubble appears in the form of a bell when the bubble is large, and in the form of a pinch-off when it is small. The impact force was measured through a PVDF sensor. It was confirmed that the impact force of the two bubbles vertically aligned on the solid surface generated more than double the impact force compared to the single bubble, and the generation time was also delayed. In the case of impulse, it was obtained that the larger the size of the bubble located near the wall, the greater the impulse amount. 본 논문은 정지된 유체 내의 고체평면 근방에서 크기가 다른 두 개의 캐비테이션 버블을 발생시켜 이 버블들이 동시에 붕괴할 때, 벽면 최대 충격력 및 충격량을 실험적으로 파악하였다. 무한 원방에서의 버블 붕괴와는 달리 벽면 가까이에서 발생하는 두 개의 버블은 버블-버블과의 상호작용뿐만 아니고, 버블-벽면과의 상호작용도 함께 일어나기 때문에 보다 복잡한 현상을 지닌다. 전기 스파크 발생장치를 통해 세 종류의 버블(반경 3.1mm, 3.8mm, 4.5mm)을 조합하여, 발생에서 붕괴까지의 전 과정에서 나타나는 충격력과 이에 해당하는 버블의 형태를 정량적으로 비교하였다. 버블-버블 간의 거리(η), 벽면과의 거리(γ)에 따라 생성된 버블의 형태를 다섯 가지로 구분 할 수 있었다. 대표적으로, 아래 버블이 큰 경우는 종의 형태로, 작은 경우는 핀치오프 형태로 나타남을 고속카메라를 통해 확인할 수 있다. 두 버블의 크기와 거리에 따라 붕괴 시 발생되는 충격력을 PVDF센서를 통해 계측하였다. 고체면에 세로로 정렬된 두 버블의 충격력은 단일버블과 비교하여 두 배이상의 충격력이 발생하고, 발생 시기도 늦어진다는 점을 확인하였다. 또한 충격량의 관점에서 보면 벽면가까이에 위치한 버블의 크기가 큰 것이 보다 큰 충격량을 발생한다는 결과를 얻었다.

Numerical Simulation on a Sand Erosion under Wave in 2D by Lattice Boltzmann Method

Nyo Me Thet Naing(뇨메텟나잉),Rho-Taek Jung(정노택) 한국해양환경·에너지학회 2019 한국해양환경·에너지학회지 Vol.22 No.4

Wernicke’s Encephalopathy and Peripheral Polyneuropathy Developed during Long Term Metronidazole Therapy in a Patient with a Brain Abscess- A Case Report -

Nyo Kyung Park,권범선,박진우,이호준,류기형,Sang Wuk Jeong,Sang Mi Noh 대한재활의학회 2011 Annals of Rehabilitation Medicine Vol.35 No.1

Metronidazole can induce serious neurologic problems including peripheral neuropathy, seizures, and encephalopathy. We examined a patient with acute Wernicke’s encephalopathy and peripheral polyneuropathy that had developed after prolonged metronidazole therapy without a history of chronic alcoholism or poor nutritional intake. The 68-year-old man had been hospitalized for a brain abscess and was treated for 10 weeks with metronidazole (2 grams per day). This patient, who showed symptoms of numbness and tingling in the legs, was referred for electromyography (EMG) and was diagnosed with peripheral polyneuropathy. A few days later, he developed sudden ataxia, dizziness, and diplopia. The neurologic examination revealed nystagmus and ophthalmoplegia, and the FLAIR brain MRI showed symmetrical high signal intensity lesions in the cerebellar dentate nucleus, midbrain, tegmentum around the periaqueductal gray matter, and tectum. After administering intravenous thiamine and stopping the metronidazole therapy, he recovered from the ophthalmoplegia and ataxia. Brain MR showed complete recovery within 3 weeks; however the EMG remained abnormal for a further 6 months, although the symptoms were almost completely resolved by this time.

Effects of Mg-ion and Ca-ion Implantations on P. gingivalis and F. nucleatum Adhesion

Sun Nyo Kang,정창모,전영찬,변응선,정용수,조리라 한국조직공학과 재생의학회 2014 조직공학과 재생의학 Vol.11 No.1

The purpose of this study was to evaluate the effects of ion implantation on Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) bacterial adhesion. Methods: Titanium (Ti) discs of 15 mm diameter and 1 mm in thickness (n = 42, 7 per group) were fabricated. Magnesium (Mg) and calcium (Ca) ions were implanted into the Ti surfaces using a plasma-source ion-implantation method. The roughness, chemistry, morphology, and contact angle of the titanium surfaces were analyzed using scanning electron microscopy, Rutherford back-scattering spectroscopy, Auger electron spectroscopy, and contact angle meter. P. gingivalis and F. nucleatum strains were cultured in anaerobic conditions at 37℃ for 72 hours, and all titanium specimens were dipped in the bacterial suspension at 37℃ for 24 hours. Specimens were examined at 1,000X× magnification using a fluorescence microscope. The number and total area of bacteria in each of 10 separate fields were determined by computer imaging analysis method. The resulting data was analyzed to assess the significance of observed differences based on the method of the surface treatment, ion implantation . Results: The number of P. gingivalis and F. nucleatum attached to the Mg- (927 and 227, respectively) and Ca-ion-implanted (1325 and 231, respectively) surfaces were greater than those attached to the non-implanted surfaces (306 and 98, P p < .001). Total area occupied by P. gingivalis adhesion was greater than those of F. nucleatum in the Mg- and Ca- ion-implanted surfaces (pP < .001). The types of ion and bacteria did not affect the amount of bacterial adhesion. Conclusion: Ion implantation enhanced the adhesions of P. gingivalis and F. nucleatum. Non-specific bonding derived from the electrostatic force affected by positively charged ions might be the predominant factor in bacterial adhesion. The possibility of specific bonding could not be ruled out in the Ca-ion- implanted surface.

감각과 신체

곽노규(Nyo-Gyu Khwag) 한국의철학회 2007 의철학연구 Vol.3 No.-

고대 중국에서 본다는 것은 사물의 형태를 보는 것이 아니라 사물을 인식한다는 통찰의 의미로 사용된 용례가 많다. 한의학에서도 본다는 것은 환자의 상태에 대한 인식행위이다. 눈으로 보고 진단하는 망진은 단순한 시각적 봄이 아니라 몸에 대한 전체적인 통찰이었다. 그래서 황제내경은 ‘눈’이라는 감각기관을 중시하고 이를 중요하게 다루었다. 눈은 다른 감각기관과 달리 오장육부의 정기精氣와 경락의 정미로운 혈기血氣가 모두 모여 기능하는 곳이다. 또한 본다는 것은 눈이라는 감각기관이 보는 것이 아니라 눈에 모인 정기와 혈기에 내재되어 있는 심신心神이 함께 보는 것이다. 편작의 투시를 망진으로 보는 이유도 여기에 있다. 망진은 몸을 뚫고 그 속을 보는 것이 아니라 몸에 대한 통찰을 통하여 기 흐름의 이상여부를 보는 것이다. 한의학의 이러한 시각에 대한 인식은 해부를 함에서도 오장육부나 혈관, 뼈 등의 구조물보다 그 속을 흐르거나 채우고 있는 기를 본질적인 것으로 본다. 그렇기에 황제내경에 해부의 목적은 구조를 살피는데 있는 것이 아니라 오장의 건강함과 약함, 경맥의 길이, 기와 혈의 많고 적음, 피의 맑고 탁함을 보는데 있다. 이것이 한의학에 해부학이 발달할 필요가 없었던 이유이다. To early Chinese people ‘to see’ was a kind of insight to the object as a whole. Similarily the activity of seeing the human body was the integral part of making diagnosis of a patient. The inspection of early Chinese medicine was not a simple gazing of the eye as a senseorgan, but the total insight to the internal state of the patient. To be sure the five sense organs in the Huang-ti-nei-ching was the agents of the five viscera and the six entrails. Nevertheless the position of the eye in human body was prominent in comparison to the other sense-organs. So to speak, the eye of human is the common agent of the internal body which constituted by the essence, the spirit, the blood and the vital-energy. For that reason, the eye-perception in early Chinese medicine was the reading the signs of the internal body which had have not the visual form but the flux of the internal life. This was the cause that there has not the tradition of the anatomical physiology in early Chinese medicine as a counterpart to that of the modern western bio-medicine.

TIre Effect of Yeongyupaedog-san on Cytokine Levels of Mouse Th1/Th2 Cells and Anti-allergic Activity in Ovalbumin-sensitized Allergic Inflammation Model

Khwag Nyo-Gyu,Hee Kang,Sung Min Park,Jinyoung Jang,Bumsang Shim,Sung Hoon Kim,Seung Hoon Choi,Kyoo Seok Ahn 한의병리학회 2006 대한동의병리학회 학술대회논문집 Vol.2006 No.9

The Use of LIF-based Instrument with 405 nm for Real-time Monitoring of Aerosolized Bio-particles

Sung Nyo Yoon,Jaekyung Lee,Duckho Kim,Hyun Sang Yoo,Kyung Yool Min,Min Cheol Kim 한국대기환경학회 2019 Asian Journal of Atmospheric Environment (AJAE) Vol.13 No.3

Bio-aerosols can affect public health depending on the origin of bio-particles (bacteria, virus etc.). Here, we attempted to assess the applicability of laser-induced fluorescence (LIF) instrument with 405 nm to real-time monitoring of bacteria and viruscontaining aerosols. For the purpose, the LIF-based BDS (Bio-aerosol Detection System) was used. The bio-particle monitoring of the BDS is based on fluorescence signals from two wavelength ranges [short wavelength range (SWR): 430-550 nm & long wavelength range (LWR): 500-600 nm] and the scattering signal. Firstly, auto-fluorophores (NADH, riboflavin, tyrosine, tryptophan) were tested to expect the monitoring ranges of the BDS for the auto-fluorophores. NADH and riboflavin showed fluorescence signals from two wavelength ranges, and the fluorescence efficiency of NADH was higher in the SWR than in the LWR and that of riboflavin was reversed. While tyrosine and tryptophan showed negligible fluorescence signals from two wavelength ranges as expected. Next, the lyophilized powders of Bacillus subtilis (BS), virus vaccines [ND (Newcastle Disease), IB (Infectious Bronchitis)] and the bacteriophage MS2 were tested to investigate the monitoring ranges of the BDS for the bio-particles. Individual virus and bacteriophage have been expected no fluorescence signals because of the absence of NADH and riboflavin fluorescing by 405 nm. Nonetheless, all the tested samples showed the fluorescence signals in the size range of 2 to 15 μm, generally known as bio-aerosol size. Considering that atmospheric virus particles are released through the respiratory organs of their hosts, just as virus vaccines from chicken embryo and MS2 from E. coli, it can be thought in turn that the BDS can also monitor bio-aerosols including virus as well as bacteria. Taken together, we suggests that the BDS, LIF-based instrument with 405 nm, is applicable for real-time monitoring of virus-containing aerosols as well as other bio-aerosols by counting the fluorescence particles and resolving their particle sizes.

連翹敗毒散 물 抽出物의 마우스 Th1/Th2 사이토카인 調節에 의한 항알레르기 효과

곽노규(Nyo-Gyu Khwag),강희(Hee Kang),명유진(Eu Gene Myung),박성민(Sung Min Park),심범상(Bum Sang Shim),김성훈(Sung Hoon Kim),최승훈(Seung Hoon Choi),안규석(Kyoo Seok Ahn) 한의병리학회 2006 동의생리병리학회지 Vol.20 No.4

e-러닝에서 학습참여도와 만족도에 영향을 미치는 자기조절학습 요소 연구

이규녀 ( Kyu Nyo Lee ),촤완식 ( Won Sik Choi ) 한국기술교육학회 2007 한국기술교육학회지 Vol.7 No.3

Phospholipase D1 mediates bFGF-induced Bcl-2 expression leading to neurite outgrowth in H19-7 cells.

Yoon, Sung Nyo,Kim, Kang Sik,Cho, Ju Hwan,Ma, Weina,Choi, Hye-Jin,Kwon, Sung-Joon,Han, Joong-Soo Biochemical Society 2012 Biochemical journal Vol.441 No.1

<P>The purpose of the present study was to investigate the role of PLD (phospholipase D) in bFGF (basic fibroblast growth factor)-induced Bcl-2 expression and to examine whether overexpressed Bcl-2 influences neurite outgrowth in immortalized hippocampal progenitor cells (H19-7 cells). We found that Bcl-2 expression was maximally induced by bFGF within 24?h, and that this effect was reduced by inhibiting PLD1 expression with PLD1 small interfering RNA or by overexpressing DN (dominant-negative)-PLD1, whereas PLD1 overexpression markedly induced Bcl-2 expression. bFGF treatment activated Ras, Src, PI3K (phosphoinositide 3-kinase), PLCγ (phospholipase Cγ) and PKCα (protein kinase Cα). Among these molecules, Src and PKCα were not required for Bcl-2 expression. PLD activity was decreased by Ras, PI3K or PLCγ inhibitor, suggesting that PLD1 activation occurred through Ras, PI3K or PLCγ. We found that Ras was the most upstream molecule among these proteins, followed by the PI3K/PLCγ pathway, indicating that bFGF-induced PLD activation took place through the Ras/PI3K/PLCγ pathway. Furthermore, PLD1 was required for activation of JNK (c-Jun N-terminal kinase), which led to activation of STAT3 (signal transducer and activator of transcription 3) and finally Bcl-2 expression. When Bcl-2 was overexpressed, neurite outgrowth was stimulated along with induction of neurotrophic factors such as brain-derived neurotrophic factor and neurotrophin 4/5. In conclusion, PLD1 acts as a downstream effector of bFGF/Ras/PI3K/PLCγ signalling and regulates Bcl-2 expression through JNK/STAT3, which leads to neurite outgrowth in H19-7 cells.</P>