PFC를 적용한 AC/DC 승압형 컨버터 설계

백형래,박수강,최연옥,한엄용,이성길 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.1

Single-Phase diode rectifiers are widely used in industry. These rectifier, however, generate many harmonic components in the AC Power line and have the poor input power factor, which may create a power quality problem for other electrical apparatus in the vicinity of the rectifier. Power factor improvement and harmonic reduction in the AC line current have become very significant problems in single-phase diode rectifiers. In this paper, the high power factor boost converter using soft switching is proposed to improve the demerit. The simulation results show the validity of the proposed system.

도체의 무조건 안정된 전자파 과도산란 해석

윤희상,이화용,정백호 湖西大學校 工業技術硏究所 2002 工業技術硏究所論文集 Vol.21 No.-

In the paper, we present a time-domain combined field integral equation(CFIE) formulation for analyzing transient electromagnetic responses from three-dimensional(3-D) closed conducting bodies. Instead of the conventional marching-on in time(MOT) technique, the solution method in this paper is based on the Galerkins method that involves separate spatial and temporal testing procedure. Triangular patch basis functions are used for spatial expansion and testing functions for arbitrarily shaped 3-D structures. The time-domain unknown current coefficient is approximated by using an orthonormal basis function set that is derived from the Laguerre functions. These basis function are also used as temporal testing functions. The method to be described results in very accurate and stable transient responses from conducting objects without an internal resonance. Detailed mathematical steps are included and representative numerical results are presented and compared.

상악 및 하악의 전방 분절 절골술을 이용한 안면 프로파일 성형술의 임상적 고찰

백세민,오갑성,윤은성,백롱민,임재호 大韓成形外科學會 1996 Archives of Plastic Surgery Vol.23 No.5

Mid and lower facial convexity is more common in Oriental people than in Caucasian and it is thought to be caused by a more anterior position of dental and skeletal structures rather than soft tissue structures, a more procumbent dentition, and a more acute interincisial angle. To improve their lower facial profile, we performed maxillary and mandibular anterior segmental osteotomies in 96 patients, by way of using palatal mucoperiosteal flap for vascular circulation of the antrior segment and plates and screws for rigid fixation. We also used wafer splint which had been made through model surgery which dental cast and tracing of cephaloghram had been needed. We could get the accurate diagnosis and know how much and which direction the anterior segment should move to get the satisfactory result or improved lower facial profile and corrected occlusal relationship with the teeth. No major complications occurred throughout the followup period except three of over0recessed lip and two of septal deviation, otherwise most of the patients were satisfied with the result.

저선량 γ선 조사가 고추의 광합성과 광 스트레스 경감에 미치는 효과

이혜연,김재성,백명화,박순철,박연일 한국환경농학회 2002 한국환경농학회지 Vol.21 No.2

고추 종자에 저선량 γ선을 조사시킨 고추 식물체의 생육과 광합성 능 및 광 스트레스 반응에 미치는 영향을 조사하였다. 저선량 4 Gy가 조사된 고추 식물체에서 광합성에 의한 산소발생이 대조구에 비해 1.5배정도 높은 것으로 나타났다. 고추 잎에 900 μmol/㎡/s의 빛의 세기로 광저해를 4시간 유도하였을 때 최대 광합성능 (Pmax)이 대조구의 경우 20%정도 감소되는 반면 4 Gy 조사구는 3% 정도의 감소를 보였다. Fv/Fm는 광저해가 진행됨에 따라 감소되는 경향을 보이며 대조구의 경우 4시간 처리시 fv/Fm 값이 50% 정도 감소되는 것을 볼 수 있었다. 반면 4 Gy조사구는 fv/Fm값이 대략 37%정도 감소되어 대조구에 비해 광 스트레스에 대해 덜 민감한 것으로 나타났다. Fo는 광저해가 진행됨에 따라 거의 변화가 없었으며 대조구나 4 Gy 조사구 사이의 차이도 거의 없는 것으로 나타났다. 광계Ⅱ의 광양자 수율인 Φ_PSⅡ과 광계Ⅱ 반응중심에 의한 여기 포획률을 나타내주는 1/Fo-1/Fm 또한 광저해가 진행됨에 따라 감소되었으며 4시간을 처리했을 경우 각각 대조구는 47%, 4 Gy 조사구는 30%의 감소를 볼 수 있었다. 비광화학적 소멸인 NPQ는 광저해가 진행됨에 따라 감소되는 경향을 보였으나 대조구와 4 Gy 조사구간에 차이는 없는 것으로 나타났다. 이러한 결과를 볼 때 종자의 종피를 투과한 저선량의 γ선이 식물의 광합성을 증대시키고 동시에 광 스트레스에 대한 저해를 감소시키는 것으로 보인다. The effect of low dose Y radiation on photosynthesis and the reduction of photoinhibition in red pepper plant was investigated. The seedling height, leaf width and leaf length of pepper were stimulated in plants grown from seeds irradiated with the tow dose of 4 Gy. The O_2 evolution in the 4 Gy irradiation group was 1.5 times greater than in the control. To investigate the effect of low dose Y radiation on response to high light stress, photoinhibition was induced in leaves of pepper by illumination of high light (900 μ㏖/㎡/s). Pmax was decreased with increasing illumination time by 20% in the control, while hardly decreased in the 4 Gy irradiation group. The photochemical yield of PSII, estimated as Fv/Fm, was decreased with increasing illumination time by 50% after 4 hours while Fo did not change. However, Fv/Fm in the 4 Gy irradiation group was decreased by 37% of inhibition, indicating that the photoinhibition was decreased by the low dose Y radiation. Changes in the effective quantum yield of PSII, Φpsu, and 1/Fo-1/Fm, a measure of the rate constant of excitation trapping by the PSII reaction center, showed similar pattern to Fv/Fm. And NPQ was decreased after photoinhibitry treatment, showing no difference between the control and the 4 Gy irradiation group. These results showed the positive effect of low dose Y radiation on the seedling growth and the reduction of photoinhibition.

초등학생의 Sports 참여와 Leadership의 관계

김백윤,조현철 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.14 No.6

The purpose of this study is to investigate sport involvement types and it's relation to the leadership among elementary students who are in the beginning of socialization through sport activity, In order to do so, the sport involvement types were examined and it's effect on the leadership was analyzed based on the study of 322 elementary students (male 161, female 161). The general conclusions of this study are followings: 1. On the investigation of sport involvement among elementary students' sexual, The affective involvement level was found to be higher both male and female groups. And there was a significantly difference in affective involvement, cognitive involvement. 2. On the leadership of elementary students according to sexual, It was shown higher male group than female group. 3. There was a relationship between sport involvement and leadership. Especially, affective involvement was shown to be highly related to the sport leadership. There was significant statistical relationship between active involvement was no related to the leadership. It was also found that active involvement was related to the innate leadership.

反復荷重에 의해 壁體에 作用하는 殘留土壓

전용백 대구대학교 산업기술연구소 1987 産業技術硏究 Vol.6 No.-

Although retaining walls are commonly designed according to classical theories, for large projects it is important to consider the effects of surcharge and cyclic loading on earth pressure acting ona retaining wall. This paper intends to investigate such effects through experiments. The contents of the investigation are effects of position of repeated loading, loading and unloading, passing frequency, and overconsolidation ratio. For the purpose of the investigation an experimental load-deflection system is developed and the system is possible to measure deflection of the wall and earth pressure due to different size of strip loading and cyclic loading. The findings from the experiments are as follows: 1. As repeated loading approaches to the wall, the measured horizontal residual earth pressure agrees well with Rowe's empirical formula, while as the loading is far from the wall the earth pressure consists with Boussinesq's and Spangler's formulas. Also it is found that below 0.6m depth from ground surface the effects of repeated loading can be nearly neglected. 2. From comparison analyses of earth pressure theories and experimental results, a regression equation is suggested herein, and earth pressure at any depth and maximum earth pressure due to cyclic loading can be estimated from the equation.

W-CDMA를 이용한 PCS 기지국용 RF 송신부의 설계 및 구현

진년강,백주기 단국대학교 1999 論文集 Vol.34 No.-

In this study, the wideband CDMA transmitter for PCS is designed and implemented. As a modulation method, the CC-OQPSK implemented as the ASIC and this modulation method has better spectral and power efficiency than conventional QPSK system because it has constant envelope characteristics. In the intermediate frequency stage using double-conversion scheme, good hamonics rejection characterisitics and gain of 20 ㏈ were obtained. The output power of two-stage RF amplifier is +21.14 ㏈m in 1.9㎓ band. It has been confirmed that the electrical characterisitics of the transmitter which is implemented in the paper satisfy with the specification of wideband CDMA transmitter that has been set to be the design standard of PCS.

한국무용 전공자의 근 기능 특성 연구

문성철,백연옥 仁荷大學校 스포츠科學硏究所 2001 論文集 Vol.13 No.-

The purpose of this study was to find the trait on the muscle strength, power and endurance of Korean dancer in high school. 16 subjects of high school dancer(Korean dancer; 8, ballerina; 8) were recruited randomly for this experimental study. All subjects were healthy dancers with out acute or chronic injuries. Subjects were tested for knee extension and flexion, ankle extension and flexion on a Cybex-II isokinetic dynamometer of made Lumex Co. in U.S.A. The results of analysis on the data obtained from each measurement were as follows: 1.The trait of muscle strength of Korean dancer was showed to higher deficit of peak torque for knee flexion between left and right, to higher peak torque(peak torque/weight ratio) for left knee extension, to higher peak torque of left ankle flexion(peak torque/weight ratio), to lower deficit of peak torque for ankle flexion between left and right, to lower peak torque of left ankle extension(peak torque/weight ratio) and the right ankle peak torque/weight ratio, and to higher left ankle ipsilateral balance. 2.The trait of muscle power of Korean dancer was showed to higher deficit of peak torque for knee flexion power between left and right, to higher peak torque(peak torque/weight ratio) for left knee extension power, to lower deficit of peak torque for knee extension power between left and right, to higher left ankle flexion power (peak torque/weight ratio), to lower left ankle extension power(peak torque/weight ratio), and to higher deficit of peak torque for ankle extension power between left and right. 3.The trait of muscle endurance of Korean dancer was showed to higher peak torque for left knee extension endurance.

대학생의 웰니스 인식에 관한 조사연구

조현철,김백윤 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.14 No.6

The purpose of study were to measurement awareness levels of collegians' wellness by the Korean Wellness lifestyle scale (Kim, Sang-Kook, 2000) and to renew awareness about one lifestyle, and to provide change behavior for good health. The subjects of these study were 422 collegian (male 237, female 185) who took classes related to heath and physical education as for cultural subjects in chonbuk. 1. The result of awareness levels of under dimensions of wellness according to the sexual, The physical dimensions was not significant difference in fitness, nutrition, drug control factors, and it shows male higher than female in smoking and drinking control factors (t=6.277, p<.001). The social, spiritual, intellectual dimensions was not significant difference. The emotional dimensions was not significant difference in cope with circumstances, tolerance factors, and it shows female higher than male in stress factors (t=3.270, p<.01). 2. The result of awareness levels of under dimensions of wellness according to the major, The physical dimensions was not significant difference in nutrition, smoking and drinking, drug control factors, and it shows higher in order of art and physical fitness, natural science, cultural science in fitness control factors (F=39.922, p<.001). The social dimensions was not significant difference in respect to others, personal relationship factors, and it shows higher in order of art and physical fitness, natural science, cultural science in voluntary service factors (F=6.378, p<.01). The spiritual dimensions was not significant difference in conviction and worth, fruitful and affection factors, and it shows higher in order of art and physical fitness, natural science, cultural science in self-accomplish factors (F=3.160, p<.05). The intellectual dimensions was not significant difference in medical knowledge, self-development factors, and it shows higher in order of natural science, art and physical fitness, cultural science in value of education factors (F=5.169, p<.05). The emotional dimensions was not significant difference in cope with circumstances, tolerance factors, and it shows higher in order of art and physical fitness, natural science, cultural science in stress factors (t=4.291, p<.05).

태극권 수련이 중년여성의 심리적 행복감에 미치는 영향

강현숙,김백윤,박미진,신영호 한국스포츠리서치 2005 한국 스포츠 리서치 Vol.16 No.2

The purpose of this study was to explore the effects of Taichichuan training on the variables of cognitive-affective states. The subjects of the study consisted of 22G middle aged women in Jeonju areas. The survey methods of this research are the 5 Likert Scale modified the Cognitive Affective States Scale by Yang. Myung-Hwan(1998). The used statistical methods for the data analysis were M. SD. Paired sample T-Test. The results obtained by the appropriate analytic processes were followed. 1. In hedonic enjoyment, Taichichuan training women were lower than non-activity women. 2. In feeling of flow, Taichichuan training women were higher than non-activity women. 3. In self-realization, Taichichuan training women were higher than non-activity women. 4. In self-confidence, Taichichuan training women were higher than non-activity women.