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RF Interference Analysis for KOMPSAT-II Spacecraft
Lim, S.B.,Kim, D.Y.,Chang, Y.K. 통신위성우주산업연구회 2001 Joint Conference on Satellite Communications Vol.2001 No.-
In general, LEO satellite uses S-band communication link for the whole satellite management, whereas the satellite payload frequently implements X-band and/or Ku-band transmitter for payload data transmission. The transmission system should have out-band rejection filter (protection circuit) to prevent any interference with the satellite receiver, so that the receiver can be normally operated. It is usually implemented in the transmitter itself but the vendor of a transmitter could not take it into account whole out of band frequency because a variety of individual satellites utilize different RF communication systems. The KOMPSAT-II, which is an earth observation satellite, is being developed by Korea Aerospace Research Institute and Korean industries. It has S-band communication system for the bus and X-band transmission system for payload data. In addition, L-band GPS Receiver is being incorporated to achieve the KOMPSAT-II mission goal. Unfortunately, the KOMPSAT-2 payload system does not have external out-band rejection~ filter nor transmitter for S-band and L-band protection. The transmitter only has band rejection filter for TDRSS. In addition, it has high gain directional antenna whose directional beam has to pass over the S-band antenna. In this paper, the analysis method is described to calculate the interference effects of the S-band spurious noise power on X-band transmitting system to S-band receiver. The S-band antenna is positioned very closely to the X-band Antenna by I .2m. We will also introduce general simple RF interference analysis method applicable to a traditional system, including advantage and disadvantages. The X-band transmitting system is often required to add the specified filter to suppress the S-band spurious signal for the safety of the receiver performance. The analysis result shows that the performance of S-band receiver is satisfied with no implementation of the specified filter.
14.6 A GeV ^28Si 중이온이 원자핵건판내에서 발생시킨 핵반응에서 생성된 2차입자의 발생각 분포
김종오,김태연,남신우,신택수,우종관,이세병,임계엽,장세덕,조재희,천병구,임인택,김기영 慶尙大學校 기초과학연구소 1990 基礎科學硏究所報 Vol.6 No.-
14.6A GeV^28Si 중이온이 원자핵 건판내에서 발생시킨 N_h=1인 핵반응에서 생성된 47개의 파쇄 α 입자와 537개의 단일하전 2차입자의 발생각들을 측정하여 변수 exp(γ-η_b)의 포괄적 분포를 회귀함수 dN=exp[a+χ{exp(γ-η_b)d{exp(γ-η_b)}로 적합시켰다. 여기서 의사신속도 γ=arctanh(cosθ)=-ln tan(θ/2)이고, 입사 중이온의 신속도 η_b=3.445이다. 그 적합결과 파쇄 α입자의 경우 χ=-0.052±0.011이고, 파쇄 p입자의 경우 χ=-0.141±0.015이었다. For LS emission angles of 47 α fragments and 537 single-charged shower particles, produced by the N_h (the number of heavyprongs)=1 interactions of 14.6 A GeV^28Si nuclei in the nuclear emulsion, the distribution of the parameter exp(γ-η_b) is well expressed by dN=exp[a+χ{exp(γ-η_b)d{exp(γ-η_b)}with χ=-0.052±0.011 for αfragments and χ=-0.141±0.015 for p 'fragments', where the pseudorapidity of secondaries γ=arctanh(cosθ)=-ln tan(θ/2) and the rapidity of incident heavy ions, η_b=3.445.
Progress in the development of heating systems towards long pulse operation for KSTAR
Kwak, J.G.,Bae, Y.D.,Chang, D.H.,Chang, D.S.,Hong, B.G.,Hwang, C.K.,In, S.R.,Jeong, S.H.,Jin, J.T.,Jung, K.S.,Kim, B.R.,Kim, J.,Kim, S.K.,Kim, T.S.,Lee, D.W.,Lee, K.W.,Oh, B.H.,Seo, C.S.,Seo, M.S.,Yoo International Atomic Energy Agency 2007 Nuclear fusion Vol.47 No.5
<P>Construction of the Korea superconducting tokamak advanced research (KSTAR) tokamak is in its final phase. For the long-pulse KSTAR discharges, the ion cyclotron range of frequencies (ICRF) and neutral beam injection (NBI) heating systems are expected to play important roles through a selective heating of ions and electrons, control of the plasma pressure and current profiles, a core fuelling and beam diagnostics for the KSTAR. In addition, the ICRF system is expected to be used for possible discharge cleaning and assisting in the tokamak startup. In this paper, the recent progress in the development of the ICRF and the NBI heating systems is described. The four-strap ICRF antenna has been successfully tested for a voltage up to 41 kV for a pulse length of 300 s (to 46 kV for 20 s) in a test chamber. A prototype KSTAR NBI system has been developed. At present, the system has successfully produced a 1 MW beam power for 200 s and a 3.5 MW output beam power for 4 s.</P>
Simulation of Rough Rice Drying by Natural Air(Ⅰ)
Chang, D. I.,Chung, D. S.,Pfost, H. B.,Calderwood, D. L. 충남대학교 농업과학연구소 1983 農業技術硏究報告 Vol.10 No.1
Simulation model of natural air grain drying was discussed and modified to predict the changes of grain moisture content and dry matter loss of rough rice drying. The modified simulation model was then validated using actual test data. A series of simulated drying tests using official weather data for 15 years from Beaumont, Texas, was taken to make minimum airflow rate and maximum bed depth of rough rice drying by natural air, under different conditions of initial moisture content of rough rice, airflow rate and harvest date.
장보현,박용규,주성후,양해석 中央大學校 基礎科學硏究所 1994 基礎科學硏究所 論文集 Vol.8 No.-
The Sr(S,Se) : Ce,Cl thin film EL devices, with the double insulating layer structure and S:Se mole ratio of 1:9, are fabricated by co-evaporation of the SrS:CeCl₃powder and elemental Se. The EL spectra of this device show the blue emission band centered at 470nm. The capacitances of the insulating layer and active layer, measured using the Sawyer-Tower circuit, are 16.9nF and 11.4nF, respectively, and the characteristic constant is 1.56. The luminance and efficiency of the thin film EL devices fabricated in this study are found to be 14.46cd/㎡ (at 1kHz, 170V) and 0.01 lm/W, respectively.
CHANG, W.-G.,LIM, B.-S.,YOON, T.-H.,LEE, Y.-K.,KIM, C.-W. Blackwell Science Ltd 2005 Journal of oral rehabilitation Vol.32 No.4
<P><SMALL>SUMMARY</SMALL> </P><P>The purpose of this study was to evaluate the effects of salicylic–lactic (SL) acid conditioner on the shear bond strength of brackets. Fluoride releasing (Light-bond) and non-fluoride releasing (Enlight) composite adhesives were used after conditioning with 0·22% salicylic + 9% lactic acid or 34% phosphoric acid. Composite adhesives were light cured with either a halogen light curing (HLC) unit for 30–50 s or a plasma arc curing (PAC) unit for 4 s. The shear bond strength was measured with an Instron. Failure modes of debonded brackets were identified based on adhesive remnants on the bracket and tooth. Salicylic–lactic acid conditioning was found to provide adequate shear bond strength. Groups conditioned with SL acid were debonded mainly at the enamel–resin interface and comparatively clean enamel surface after debonding was observed than those conditioned with phosphoric acid. Using confocal laser scanning microscopic examinations, it was found that demineralization patterns between SL acid and phosphoric acid conditioned groups were not different when the same adhesive was used. The SL acid conditioner did not reduce the demineralization. Light-bond adhesive showed less demineralization than Enlight adhesive. The PAC unit can be recommended as an alterative to the HLC unit because it significantly reduces the irradiation time.</P>