http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Numerical Analysis of Flows around a Sphere
Genichiro Ebe,Etsuo Morishita 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-
A sphere is a simple structure and it is used in many things, particularly in sports fields. A soccer ball is an example. There exists a critical Reynolds number around at Re = 10? and sharp drag reduction is observed. This is caused by a transition from a laminar boundary layer to a turbulent one. The present authors attempt to analyze a flow around a sphere numerically. Our particular interest is to invcstigatc the three-dimensional unsteady flow of a sphere. The MAC method is used to solve the incompressible Navier Stokes equations. A special grid is developed for the present calculations. Singularities around poles are carefully avoided by combining two polar meshes. It is found that the wake of a sphere is complicated and unsteady movements is dominant at Re = 10³~10⁴ range. The periodicity is also observed, although it is not regular as in the two-dimensional Karman vortex street. Two of the three vortex components are stationary on the latter surface of a sphere, while the rest of the vortex components shows a very complex movement. The present study might contribute to the understanding of the How around the soccer ball, together will, other spherical objects in the sports field.
수면무호흡증 환자에서 수면다원검사와 두부규격방사선사진을 이용한 하악전방이동장치의 치료효과에 관한 연구
김성헌,김이비,정진우,Chung, Jin-Woo,Kim, Ebee,Kim, Sung-Hun 대한안면통증구강내과학회 2013 Journal of Oral Medicine and Pain Vol.38 No.2
본 연구의 목적은 폐쇄성수면무호흡증 환자의 표준 수면다원검사와 두부규격방사선사진 분석을 이용하여 하악전방이동 장치의 치료 효과에 영향을 주는 요소들을 분석하는데 있다. 서울대학교치과병원 구강내과에 내원한 27명의 수면무호흡증 환자들을 대상으로 측두두부규격방사선사진 촬영 및 계측점을 이용하여 SNA, ANB, $AH{\bot}MP$, AH-C3, SPT, PNS-U, NAS, SOAS, MOAS, HAS 등을 분석하였으며, 하악전방이동장치를 제작하여 장치 장착 전후 수면다원검사를 시행하였다. 장치 장착 전후 수면무호흡지수, 산소포화도, 각성지수 등을 비교하였고 무호흡-저호흡지수와 두부규격방사선사진 계측치와의 상관관계를 분석하였다. 하악전방이동장치 장착 전후 전체 수면무호흡지수, 최소 산소포화도 및 전체 각성지수에서 통계적으로 유의한 개선이 있었다. 또한 장치 장착 전후 NREM수면에서 산소분압과 무호흡지수에서 통계적으로 유의한 개선이 있었던 반면 REM수면에서는 산소분압과 무호흡지수에서 통계적으로 유의한 개선이 없었다. 장치 장착 전후 수면의 단계에서 stage I의 유의한 감소, stage II와 REM수면의 유의한 증가가 관찰되었으나 stage III의 변화는 유의하지 않았다. 두부규격방사선사진 계측치중 SNA와 SOAS가 전체 수면무호흡지수와 유의한 상관관계가 관찰되었으며 NAS는 앙와위 수면무호흡지수와 유의한 상관관계가 관찰되었다. 하악전방이동장치의 효과는 환자의 ANB 각도가 클수록 유의하게 높게 나타났다. 표준 수면다원검사를 이용하여 하악전방이동장치 장착 전후를 비교해 보았을 때 하악전방이동장치는 수면무호흡증 치료에 효과적인 치료법이며 두부규격방사선사진 분석은 수면무호흡증 환자를 평가하고 치료 결과를 예측하는 데 유용할 수 있다. Objecives : The purpose of the study was to evaluate treatment outcome of mandibular advancement device(MAD) in obstructive sleep apnea (OSA) patients using full night polysomnography and cephalometry. Methods : Twenty-seven OSA patients were confirmed by full night, lab-attended polysomnography. Cephalometric examinations were conducted to obtain SNA, ANB, $AH{\bot}MP$, AH-C3, SPT, PNS-U, NAS, SOAS, MOAS, and HAS. Mandibular advancement devices (MADs) were fabricated and delivered for all subjects. After acclimation period of MAD, the second polysomnographic examinations were conducted in the same manner. Polysomnographic variables were compared between before and after MAD placement. Also, correlation coefficients were calculated between apnea-hypopnea index (AHI) and each item of cephalometric parameters. Results : There were significant improvements in total AHI, lowest $SpO_2$, and total arousal index after MAD therapy. Also, there were significant improvements in NREM $SpO_2$ and NREM AHI, but not in REM $SpO_2$ and REM AHI with MAD. Stratifying the sleep stage, there were significant decrease in stage I and significant increases in stage II and REM, but change in stage III was not significant. SNA and SOAS were significantly correlated with total AHI and NAS was significantly correlated with supine AHI. ANB was significantly associate with the effect of MAD. Conclusions : MAD is an effective treatment in OSA patients comparing polysomnographic variables before and after treatment. Cephalometric examination can be useful to evaluate OSA patients and predict treatment outcome of MAD.
Saleh B.,Yousef Ali M.,Ebeed Mohamed,Abo-Elyousr Farag K.,Elnozahy Ahmed,Mohamed Moayed,Abdelwahab Saad A. Mohamed 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.6
The main target of this paper is to allow renewable energy resources (RES) to participate eff ectively within hybrid micro grids via an optimal proportional integral- derivative (PID) controller. This paper proposes two techniques of optimal PID controllers in a hybrid renewable generation energy system. These techniques are particle swarm optimization (PSO) and lightning attachment procedure optimization (LAPO). The hybrid renewable generation energy system in this study includes a photovoltaic source, wind turbine, and battery storage, which are connected to a point of common coupling via DC/DC boost converters. The controller at the inverter consists of a current controller and voltage source controller, which results in three PID gains at each controller. In order to obtain the PID gains, a time domain objective function is formulated in terms of the voltage, and current errors. The obtained results with the individual advanced optimization LAPO and PSO algorithm are compared. The results display that the developed LAPO algorithms give better results compared to the conventional PSO at the input and output current, voltage, and power. All the results have been taken under several operating conditions of wind turbine (wind speed) and solar sun (changing irradiance and temperature).
Possible Translocation of Periodontal Pathogens into the Lymph Nodes Draining the Oral Cavity
G. Amodini Rajakaruna,Makoto Umeda,Keisuke Uchida,Asuka Furukawa,Bae Yuan,Yoshimi Suzuki,Ebe Noriko,Yuichi Izumi,Yoshinobu Eishi 한국미생물학회 2012 The journal of microbiology Vol.50 No.5
Numerous publications have reported the presence of periodontopathogenic bacteria in peripheral and central vascular lesions. However, it is unclear how this bacterial translocation occurs. The objective of this study was to investigate whether periodontopathic bacteria are translocated to lymph nodes proximal to the oral cavity. Obtaining lymph node samples is not ethically feasible unless they are excised as part of the surgical management of patients with cancer. This study analyzed formalin-fixed and paraffin-embedded lymph nodes, histologically negative for cancer cell invasion, that were excised from 66 patients with histories of head and neck cancer. Real-time PCR was performed to amplify the 16S ribosomal DNA fragments from Porphyromonas gingivalis,Treponema denticola, Aggregatibacter actinomycetemcomitans,Tannerella forsythia, and Prevotella intermedia. The relationship between bacterial detection and cancer severity,gender, and the use of anti-cancer therapy was examined by Fisher’s exact test. P. gingivalis, T. forsythia, and P. intermedia were present in 17%, 8%, and 8% of the samples of submandibular and submental lymph nodes, respectively. There were no significant relationships between bacterial detection and the cancer disease status, patient gender or use of anticancer therapy. According to these data, it appears that the translocation of periodontopathic bacteria may occur via lymphatic drainage, irrespective of the cancer disease status, gender or anticancer therapy.