http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
단순화된 볼륨요소 개념을 이용한 인쇄회로기판 동 특성에 관한 연구
서현석,채장수,김춘삼,Seo, Hyeon-Seok,Chae, Jang-Su,Kim, Chun-Sam 통신위성우주산업연구회 2002 Joint Conference on Satellite Communications Vol.2002 No.-
인쇄회로기판은 다수의 구리 적층판과 글래스 에폭시로 구성되어진다. 각 구리적층판은 최적의 임무수행을 위해 복잡하고 서로 다른 형태의 패턴을 가지게 된다. 이 때, 기판의 강성은 각 적층판에 많은 영향을 받고 있으며, 이와 같은 이유로 기판의 동특성값인 강성의결정이 중요하게 되었다. 다목적 실용위성에서 사용된 전력조절기는 크게 2가지 형태의 보드를 장착하게 된다. 본 연구에서는 다목적 실용위성의 전력조절기에서 사용된 기판의 강성 결정을 위한 방법을 제시하고 복합소재 고전적 이론을 이용하고자 하였다. 또한 실제 진동환경시험을 통한 결과를 토대로 이와 같은 방법을 입증하고자 하였다. Printed Circuit Boards are composed of multi-layered copper(CU) plate and glass epoxy. Each copper layer has the complicated and different pattern to correctly operate for its mission. In that case, PCB(Printed Circuit Board) stiffness are affected by the copper layers. By reasoning of this complicated copper layer pattern, it is difficult to determine the PCB stiffness. Solar array regulator for KOMPSAT(Korea Multi Purpose SATellite) has two type of PCB. In this study, the methodology of calculation of the PCB stiffness for KOMPSAT SAR unit is suggesteol considering the concept of simplified representative volume element and it will be correlated with the results under KOMPSAT vibration test condition.
서현석(Hyeon-Seok Seo),김윤제(Youn-Jea Kim) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-
In modern society, the air-conditioner(A/C) demand is increasing owing to its improvement of the standard of living. The compact and slim-sized A/C has been developed, and the compact design of parts is also demanded. If the component of the drain pump is not optimized, it will spend a lot of electric powers more than its needs. In this paper, numerical simulations of the 3D turbulent flow in a drain pump with different rotating speeds are performed. The rotational frequency is located in the range from 1000rpm to 2500rpm. Besides, applying the volute casing makes an analysis of the efficiency in configuration of existing. Using a commercial code, FLUENT, the velocity and pressure distributions are obtained under steady, turbulent flow and no-slip conditions. A multiple rotating frame approach is adopted to simulate the flow field generated by impeller of the pump. Turbulence closure is achieved using a RNG к-<SUP>ε</SUP> model. Results are graphically depicted with various geometrical configurations and operating conditions.
서현석(Hyeon-Seok Seo),김태안(Tae-An Kim),김윤제(Youn-Jea Kim) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
The objective of this paper is to elucidate the characteristic performance of the mini-vacuum pump with various heights of eccentric shaft. The mini-diaphragm pump is composed of DC motor, eccentric shaft and diaphragm and it is operated by PCB panel. The height of eccentric shaft is changed that controls the quantities of air flow to improve the performance of vacuum pressure. This device is manufactured in order to embody the vacuum pressure with 200 ㎜Hg. The heights of eccentric shaft which is used in present experiment are located in the range from 3 ㎜ to 5.5 ㎜. The vacuum pressure distributions with each height of eccentric shaft was measured and the results were graphically depicted.
천식 소아에서 호기산화질소 농도와 기도 과민성, 혈액 호산구 수, 혈청 호산구 양이온 단백 농도와의 상관관계
서현석 ( Hyeon Seok Seo ),정보현 ( Bo Hyun Chung ),박하늘 ( Ha Neul Park ),서성철 ( Sung Chul Seo ),( Bauer Siegfried ),송대진 ( Dae Jin Song ),정지태 ( Ji Tae Choung ),유영 ( Young Yoo ) 대한소아알레르기호흡기학회(구 대한소아알레르기 및 호흡기학회) 2012 소아알레르기 및 호흡기학회지 Vol.22 No.3
Purpose: The measurement of fraction of nitric oxide (FeNO) is a noticeable tool that reflects airway inflammation in asthmatic patients. We wanted to find out the relationship between pulmonary function, bronchial hyperresponsiveness (AHR), blood eosinophilic inflammatory markers and FeNO level before and after methacholine bronchoprovocation test in asthmatic patients. Methods: Fifty-five children, who visited the Allergy Clinic of Korea University Anam Hospital from March 2011 to February 2012, due to asthmatic symptoms, such as history of episodic wheezing or dyspnea during the previous year and resolved after using bronchodilators, were enrolled. We performed the baseline pulmonary function and methacholine bronchoprovocation test in the enrolled patients. Blood eosinophil counts and blood eosinophil cationic protein (ECP) were measured. FeNO levels were measured before and after the methacholine bronchoprovocation test. Results: The mean FeNO levels (36.3 ppb) fell after methacholine bronchoprovocation test (25.7 ppb). Forced expiratory volume in one second (FEV1) %pred inversely correlated both with FeNO level before (R2=0.07, P =0.029) and after (R2=0.059, P =0.01) methacholine bronchoprovocation test. The provocative concentration, causing a 20% decrease in FEV1 to methacholine (methacholine PC20) inversely correlated both with FeNO levels before (R2=0.086, P =0.001) and after (R2=0.141, P =0.001) the challenge. FeNO level measured at bronchoconstriction state significantly correlated with blood eosinophil counts (R2=0.112, P =0.028). Serum ECP levels correlated FeNO level, neither before nor after bronchoprovocation. Conclusion: The baseline FeNO levels were higher in asthmatic children. However, FeNO levels rather decreased after methacholine induced bronchoconstriction. Repeated spirometry maneuver was considered to have an effect on reducing FeNO levels. FeNO correlated with pulmonary function, airway AHR and blood eosinophil counts.
최적화 해석기법을 적용한 자동차 제상성능 해석기술 개발
서현석(Hyeon-Seok Seo),서진원(Jin-Won Seo),최봉근(Bong-Keun Choi) 한국자동차공학회 2019 한국자동차공학회 학술대회 및 전시회 Vol.2019 No.11
In this study, we developed the numerical analysis method to improve the defrost performance on the windshield using the multi-objective optimization method based on the CFD. The configurations of guide-vane and discharge angles in the center DEF duct section which are main design factors of the defrost performance were set to the design parameters for this study. And also, the discharge mass flow rate from the HVAC which is transferred to the windshield and the discharge areas in the center DEF duct were set to the objective functions to find the optimal design. In case of using these methods, it is possible to reduce the calculation time, and effectively analyze the results from it by controlling the design parameters systematically. These methods also make it possible to check the performance rapidly, and propose the optimal design through the analytical verifications on the initial design.
서현석(Hyeon-Seok Seo),전현주(Hyun-Joo Jeon),김영재(Young-Jae Kim),김진백(Jin-Baek Kim),박성관(Sung-Kwan Park),김윤제(Youn-Jea Kim) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
At present, many studies on the air-conditioning systems are more focused on the individual thermal comfort than the thermal efficiency due to increase of the concern of health. Numerical analyses were carried out for investigating the flow characteristics in the room, including the impeller, the rearguider, the stabilizer and the blade of the diffuser region in the RAC. Especially, two different types of blade in the diffuser region, single blade and double blades, were numerically estimated. Using a commercial code, FLUENT, two-dimensional steady air thermal flow fields are calculated with different rotating speeds of impeller. The rotational frequency of impeller is located in the range from 900 rpm to 1200 rpm. Turbulence closure is achieved using a standard k-ε model. A moving reference frame approach is adopted to simulate the flow field generated by impeller in the RAC. Results are graphically depicted with various geometrical configurations and operating conditions.