Electromagnetic fields of all frequencies represent one of the most common and fastest growing environmental influences, about which anxiety and speculation are spreading. All populations are now exposed to varying degrees of electromagnetic field, and the levels will continue to increase as technology advances. The objectives of this study were to measure and analyze emitting characteristics of extremely low frequency electromagnetic field at micro-environments. We measured magnetic field at microenvironments such as home, school, educational institute, internet pc game room for children attending the primary school. The range of time weighted average (TWA) of 60 Hz EMF in micro-environment were 0.26∼ 7.62 mG and the highest TWA 7.62 mG was measured in PC room possessed more than 50 computers. We will measure personal exposure levels of primary students and analyze correlation between major micro-environments and personal exposure level.

We have reviewed the magnetic activity in close binaries. Solar like magnetic activity indicators such as photometric spots, chromo spheric emission, coronal X-ray and radio emission, and flare activity are commonplace in many cool stars with convective envelopes. Using the UV spectra we confirmed the strength of stellar activity increases with more rapid rotation and later spectral types which corresponds to the increasing depth of the star's convective envelope. Apart from very young stellar objects such as T Tauri stars, the stars with the highest levels of activity are close binary systems composed of cool stars, i.e., the chromospherically active binaries such as RS CVn, BY Dra, W UMa and related systems. The IUE low and high dispersion spectra of V711 Tau, VW Cep and SW Lac are used for ultraviolet photometry and for a variation study of chromospheric activity. Evidence of chromospherically activity is indicated by the intensity variation of the Mg II emission line with orbital phase.

본 연구의 목적은 냉연공장 폐수재이용을 위해 3단 역삼투시스템 사용시 각단에서의 투과특성을 조사하는 것이다 판틀형 모듈 7개를 사용하여 회수율이 75% 가 되도록 3단 (배열 : 4+2+1) 으로 구성하여 장기간에 걸친 pilot test를 통해 막오염 진행에 따른 각 단에서의 유량 및 수질변화를 조사하였다 실험결과 각 단 모듈 1개당 평균 투과수량은 운전초기에는 1단, 2단, 3단의 순서로 많았으나 운전시간이 경과하며 막오염이 진행됨에 따라 1단은 감소하는 반면 2단은 거의 변화가 없고 3단의 투과수량은 증가하였다 즉 막오염은 주로 1단에서 발생하며 점차 2단. 3단으로 진행되는 것을 확인할수 있었다. 한편 투과수 수질은 예상한 것과 같이 1단이 가장 우수하였고 다음으로는 2단, 3단의 순서였으며 막오염에 영향을 받지않았다.

The spectral types of stars can be classified by using Balmer discontinuity(DB DB ) and wavelength(λB λB ) expressed in terms of effective temperatures appeared in Balmer discontinuity. In this research, in order to classify stars, we used the well established observational data of high dispersion spectrophotometry for the spectral types and luminosity classes of stars in the Breger(1976) catalogue. Balmer discontinuity by effective temperatures of stars was accurately measured, and the λB λB was replaced to luminosity classes of MK system, because of the close relationship between the As and luminosity classes. We measured the energy gradients(ϕR ϕR ) of stars which were expressed as a function of spectral types in the interval of λλ4,000∼4600\AA λλ4,000∼4600\AA , and then obtained a new physical parameter(ϕ ϕ ) from the DB DB and ϕB ϕB . The new parameter, ϕ ϕ can be used instead of HD classifications of stars and can be used widely for spectrophotometrical classifications of stars.

The environmental structure of T Tauri star can be understood by its continuum energy distribution. We suggest four evolutionary stages on the base of this environmental change from molecular cloud to the main sequence. A protostar is embedded in a dense envelope which can be attributed to the overall infrared region in continuum spectra. The infalling material from the envelope results in producing a hump in the mid-infrared region. This matter produces a surrounding disk around a central star afterwards. The disk emission changes the spectral index in the overall infrared region. The disk will be developed to a ring structure owing to the formation of planets by its instability and/or the cleaning effect of the inner region of the disk by a central star outflow, contributing to producing a hump in the far-infrared region. The pre-main sequence evolution points of T Tauri stars in H-R diagram strongly support the environmental structure evolution.

The temperature effects of the KNU UBV photometric system are investigated, using the HAMAMATSU 1P21 data. The variation of the passband width of V-band with temperature is about 5\AA/∘C while those of B-band and U-band are negligible. This large effect of V-band causes a significant variation of V-mag. and (B-V)-color with temperature such as ∼0.02mag/∘C ∼0.02mag/∘C in both cases. This result strongly suggests that in the photometric observations of binary stars, the temperature effects of the response of photomultiplier and the passband of filters must be considered to avoid the systematic variation in magnitude and color particularly at the minimum of light curve.

전남 지방의 단감나무에 기생하는 짝지벌레 중 우점종인 뿔밀깎지벌레의 기주범위 발생소장 및 각 태별 생육특성을 조사한 결과는 다음과 같다. 기주식물은 총 34과 66종이 조사 되었으며 그 중 나팔꽃, 명아주, 콩, 망초, 들깨, 사철베고니아등 6종이 새로이 조사되었다. 각 태별 발생소장은 난이 5월 상순-6월 하순까지 발생하였으며 최성기는 6월 상순이었고 유충은 6월 중순-10 월 중순까지 존재하고 최성기는 7월 상순-8월 중순이었으나 화학적 방제가 가장 효과적인 시기는 6월 하순으로 추정된다. 산란수는 평균 1,073 177.3개 이었고 부화율은 평균 97.3%로 광주기 및 처리온도에는 크게 반응하지 않았다. 각 태별 기간은 란이 23.4일, 유충이 128.3일, 자성충은 213.3일이었다.