주파수 가변 고속 디지털 MRI 모뎀 RF부 설계와 구현

김용철,박현대,김대진 전남대학교 전자통신기술연구소 2001 전자통신기술논문지 Vol.4 No.1

In this paper, we designed and made RF block of variable frequency digital modem for high speed MIRI system that can support not only multi-nuclei system but also any magnetic intensity(1.0T~3.0T). We executed simulation of fixed frequency digital modem using fixed band pass filter(BPF), variable frequency digital modem using variable band pass filter(tunable filter). Based on these simulations, variable band pass filter(tunable filter) named Micropole is ordered and manufactured. We designed and made RF block of variable frequency digital modem for high speed MRI system using variable band pass filter(tunable filter). And then we tested this board using PC and function generator and observed the output spectrum using spectrum analyzer. These spectrums are very clear and wide bandwidth about 500KHz and the level of main spectrum is 60~70dB more than harmonics or spurious. This difference of level is available for MRI system.

상지 복합부위통증증후군 I형 환자에서 시행한 8극 척수자극술 - 증례보고 -

김용철,김성현,조지연,홍지희,Kim, Yong Chul,Kim, Sung Hyun,Cho, Ji Yeon,Hong, Ji Hee 대한통증학회 2007 The Korean Journal of Pain Vol.20 No.2

The most important factors for successful stimulation of the spinal cord are strict patient selection and proper lead position. To ensure proper lead position, paresthesia produced by the stimulator should cover all of the areas in which pain is occurring. Until recently, only the quadripolar electrode lead has been used in for spinal cord stimulation in Korea, however, the 8 electrode lead was recently introduced to offer greater programming options and enhance the precision with which paresthesias is delivered to the desired sites. In addition, because the 8-electrode lead has a longer electrode span, it provides greater dermatomal coverage of up to 2 vertebral segments. Furthermore, the 8-electrode lead allows electronic repositioning of the stimulation to accommodate changing pain patterns, thereby reducing the need for lead revisions due to lead migration. Here, we present a case in which complex regional pain syndrome type I was successfully managed using an 8-electrode lead to induce spinal cord stimulation.

이면교잡에 의한 강낭콩 F₁ 세대의 조합능력 검정

김용철,Kim Yong-Chul 한국생명과학회 2005 생명과학회지 Vol.15 No.2

강낭콩 육종을 위한 기초 자료를 얻고자 형질상호간의 특성이 다른 7개 품종과 이들을 이면교잡하여 얻은 $F_{1}$ 종자를 재료로 각 형질에 대한 조합능력을 추정한 결과, 주당립수를 제외한 전 형질에서 일반조합능력의 값이 특정조합능력의 값보다 크게 나타났다. 일반조합능력의 효과를 보면 Felibon이 주당립수와 개화일수에서, Local variety $\#1$이 100립중과 경장 등에서 효과가 높았고, Local variety $\#2$는 주당립중과 100립중에서, Processor는 주당립중과 생육일수에서, Kaboom은 개화일수와 생육일수에서, $BO_{22}$는 주당립중과 100립중에서 효과가 높게 나타났다. 특정조합능력 의 효과에서는 $Felibon{\times}Renka$, Local variety $\#1{\times}Processor$, Local variety $\#2{\times}Processor$ 등의 조합들이 개화일수와 생육일수에서 높은 부의 효과를 보여 조숙품종 육성조합으로 유망하였다. $Felibon{\times}Local$ variety $\#1$, $Felibon{\times}Renka$ and Local variety $\#2{\times}BO_{22}$등의 조합들은 수량형질에서 높은 정의 효과를 보여 다수성 품종 육성조합으로 유망하였다. The studies were conducted to obtain basic informations on inheritance of some quantitative characters in kidney bean (Phaseolus vulgaris L.). Seven parents (Felibon, Renka, Processor, Kaboom, $BO_{22}$, Local variety $\#1$ and Local variety $\#2)$ and $F_1$ hybrids of 21 crosses from a set of diallel cross among varieties were used to estimate combining ability for eight agronomic characters such as days to flowering, days to maturity, stem length, pod numbers per plant, pod length, grain numbers per plant, 100-grain weight and grain weight per plant. General combining ability (GCA) and specific combining ability (SCA) were significantly different among all characters, and values of GCA were greater than those of SCA in all characters except number of grains per plant. In effect of GCA, Felibon expressed high GCA effect for days to flowering and number of grains per plant. Local variety $\#1$ showed high GCA effect for 100-grain weight and stem length. Local variety $\#2$appeared to high GCA effect for 100-grain weight and grain weight per plant. Processor expressed high GCA effect for days to maturity and grain weight per plant. Kaboom showed high GCA effect days to flowering and days to maturity. $BO_{22}$ appeared high GCA effect for all characters except for days to flowering, days to maturity and stem length. In the SCA effect, crosses of Felibonx Renka and Local variety $\#2{\times}Processor$ exhibited in high negative effect for days to flowering. Thus, these crosses were evaluated to useful for breeding early maturing variety. Crosses of breeding high yield variety were considered of $Felibon{\times}Local$ variety $\#1$, $Felibon{\times}Renka$ and Local variety $\#2{\times}BO_{22}$.

Methodology of Wind Load Evaluation of Low-Rise Building Surrounded by Similar-Sized Low-Rise Buildings

김용철,Kim, Yong-Chul Korean Association for Spatial Structures 2013 한국공간구조학회지 Vol.7 No.5

비정형 초고층 건물의 변동 풍압

김용철,칸다 준,타무라 유키오,윤성원,Kim, Yong-Chul,Kanda, Jun,Tamura, Yukio,Yoon, Sung-Won 한국공간구조학회 2013 한국공간구조학회지 Vol.13 No.1

Recent tall buildings tend to have unconventional shapes as a prevailing, which is effective for suppressing across-wind responses. Suppression of across-wind responses is a major factor in tall building projects, and the so called aerodynamic modification method is comprehensively used. The purpose of the present study is to investigate the pressure fluctuations on tapered and setback tall buildings, including peak pressures, power spectra and coherences through the synchronous multi-pressure sensing system techniques. And flow measurements around the models were conducted to investigate the condition of vortex shedding. The results show that by tapering and setback, different distributions of mean pressure coefficients at leeward surface were found, which is caused by the geometric characteristics of the models. And the power spectra of wind pressures at sideward surface become wideband and the peak frequencies are different depending on heights, which makes the correlation near the Strouhal component low or even negative. The differences in shedding frequencies were also confirmed by the flow fields around the models.

솔라윙 시스템의 풍진동 특성 평가

김용철,윤성원,Kim, Yong Chul,Yoon, Sung-Won 한국공간구조학회 2016 한국공간구조학회지 Vol.16 No.1

Aerodynamic performance of solar wing system has been evaluated through wind tunnel test. The test model has 12 panels, each supported by 2 cables. The panels were installed horizontally flat, and gaps between panels were set constant. Sag ratios of 2% and 5%, and wind directions between $0^{\circ}$ and $90^{\circ}$ were considered. Mass of test model was determined considering the mass of full scale model, and Froude number and Elastic parameter were satisfied by adjusting the mean wind speed. From the wind tunnel test, it was found that the aerodynamic performance of the solar wing system is very dependent on the wind directions and sag ratios. When the sag was 2%, the fluctuating displacements between the wind directions of $0^{\circ}$ and $30^{\circ}$ increase proportionally to the square of the mean wind speed, implying buffeting-like vibration and a sudden increase in fluctuating displacement was found at large mean wind speed for the wind directions larger than $40^{\circ}$. When the wind direction was larger than $60^{\circ}$, a sudden increase was found both at low and large mean wind speed. When the sag ratio is 5%, distribution of mean displacements is different from that of sag ratio of 2%, and the fluctuating displacements show very different trend from that of sag ratio of 2%.

단면의 변의 수가 초고층 건물의 공력특성에 미치는 영향

김용철,반디 에스와라 쿠마,유키오 타무라,요시다 아키히또,윤성원,Kim, Yong-Chul,Bandi, Eswara Kumar,Tamura, Yukio,Yoshida, Akihito,Yoon, Sung-Won 한국공간구조학회 2013 한국공간구조학회지 Vol.13 No.3

A series of wind tunnel tests were conducted on 7 super-tall buildings with various polygon cross-sections, including triangle, square, pentagon, hexagon, octagon, dodecagon, and circular. The primary purpose of the present study is to investigate the effect of increasing number of sides on aerodynamic characteristics for super-tall buildings. Wind tunnel tests were conducted under the turbulent boundary layers whose power-law exponent is 0.27. Fluctuating wind pressures from more than 200 pressure taps were recorded simultaneously, and time series of overturning moments were calculated considering tributary area of each pressure tap. The results show that the overturning moment coefficients and the spectral values decrease with increasing number of sides, and the largest mean and fluctuating overturning moments were found for the triangular super-tall building, and the largest spectral values were found for the square super-tall building. The analysis should be conducted more in detail, but currently it can be roughly said that there seems to be a little differences in the aerodynamic characteristics for the super-tall buildings whose number of sides is larger than 5 or 6.

교수매체 제작과 그 활용을 통한 학습의 효율화 방안 -과학, 사회과목을 중심으로-

김용철,Kim Yong-Chul 한국문헌정보학회 1992 한국문헌정보학회지 Vol.22 No.-

The main purpose of the school library is to present the various kinds of instructional media for an effective instruction including not only books, but also audiovisual materials and equipments. But unfortunately our school libraries have only books for the students and faculties at this time. But hereafter school library should house the various kinds of audiovisual media as well as printed media for the promotion of scholarstic achivemint. With a view to promoting the teaching method, and at the same time improving the scholarstic achivement of the students, instructional media were used in the class. To verify the efficiency of the instructional media, transparencies were used in the social science class of the 1st grade in the middle school and the natural science class of the 1st grade in the high school. In consequence, the academic achievement of the experimental class in which instructional media were used is superior to that of controlled class in which the textbook was only used. In < Social Science I >, the mean difference between the experimental class and the controlled class is 4.199 marks. And the difference, 0.032 is verified as a significant value in concordance to the t-test. In < Natural Science I >, the mean difference of the experimental class over the controlled class is 6.333. And the difference, 0.034 is verified as a significant value in concordance to the t-test. As shown in the above experimental research, using various kinds of the instructional media is more efficient than using textbook only. As a result of the questionaire on using the instructional media, most of the students desire to use of them continually because the use of the instructional media induce the interest, promote the comprehension, and entice the development of better memories.

풍압과 변위의 동시계측을 통한 고층건물의 공력 특성 평가

김용철,로 위안롱,윤성원,Kim, Yong Chul,Lo, Yuan-Lung,Yoon, Sung-Won 한국공간구조학회 2017 한국공간구조학회지 Vol.17 No.1

Vortex-induced vibration and instability vibration of tall buildings are very important fluid-structure interaction phenomenon, and many fundamental questions concerning the influence of body movement on the unsteady aerodynamic force remain unanswered. For tall buildings, there are two experimental methods to investigate the characteristics of unsteady aerodynamic forces, one is forced vibration method and the other is free vibration method. In the present paper, a free vibration method was used to investigate the unsteady aerodynamic force on tall building whose aspect ratio is 9 under boundary layer simulating city area. Wind pressures on surfaces and tip displacements were measured simultaneously, and the characteristics of tip displacements and generalized forces were discussed. It was found that variation of across-wind displacements showed different trend between the case when wind speed increases and wind speed decreases, and the fluctuating generalize forces in across-wind direction of vibrating model are larger than that of static model near the resonant wind speed and approach to the static value. And for higher wind speed range, there were two peaks in across-wind power spectra of generalize forces of vibrating model, which means that two frequency components are predominant in unsteady aerodynamic forces.

지방자치제하에서 여성정치참여의 실태와 정책방향

김용철 ( Yong Chul Kim ) 한국정책학회 2007 韓國政策學會報 Vol.16 No.4