• Title/Summary/Keyword: (2,M)-filters

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AN ANALYSIS OF INFRARED IMAGES OF JUPITER IMPACTED BY P/SHOEMAKER-LEVY 9

  • KIM YONG HA;SUNG KIYUN;KIM SANG JOON;COCHRAN W. D.;LESTER D. F.;TRAFTON L.;CLARK B. E.
    • Journal of The Korean Astronomical Society
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    • v.29 no.2
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    • pp.245-253
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    • 1996
  • We have analyzed infrared (IR) images of Jupiter which was observed at the McDonald Observatory, Texas, U.S.A., during the P/SHoemaker-LEvy 9 (SL9) impact period and about one week after the last impact. The IR images were obtained on the 2.7m telescope using a NICMOS array with filters to isolate the $1.5{\mu}m\;NH_3\; band,\;the\;2.3{\mu}m\;CH_4\;band,\;the\;2.12{\mu}m\;H_2\;S(0)$ pressure-induced absorption, and the continua at $1.58{\mu}m\;and\;2.0{\mu}m$ (short K-band). All images except those with the $1.58{\mu}m$ continuum filter show bright impact sites against the relatively dark Jovian disk near the impact latitude of about $45^{\circ}$ S. This implies that dusts originated from the impacts reflect the solar radiation at high altitudes before absorbed by stratospheric $CH_4,\;NH_3 \;or\;H_2$. The impact sites observed with the $2.3{\mu}m$ filter are conspicuously bright against a very dark background. The morphology of impact sites, G, L, and H at 2.3 and $2.12{\mu}m$ filters shows clearly an asymmetric structure toward the incident direction of the comet fragments, in agreement with the studies of visible impact images obtained with the Hubble Space Telescope. Comparisons of reflectances of G, L, and H sites with simple radiative transfer models suggest that optically thick dust layers were formed at high altitudes at which methane absorption attenuates incoming sunlight only by about $1\%$. The dust layers in these sites seem to form at about the same altitude regardless of the magnitude of the impacts, but they appear to descend gradually after the impacts. The dust layers have optical depths of 2-5, according to the models.

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Fabrication of Porous Mullite Ceramics and Its Properties (다공성 Mullite 세라믹스 제조 및 그 특성)

  • 김병훈;나용한
    • Journal of the Korean Ceramic Society
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    • v.31 no.3
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    • pp.275-281
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    • 1994
  • Mullite ceramics have recently been utilized as ceramic gas filters for high-temperature treatment of solid wastes due to their low thermal expansion coefficient and high refractoriness under load. In this experiment, mechanical, thermal and microstructural properties of porous mullite ceramics, which were used as carriers and high-temperature gas filters in food industry, were investigated as a function of starting raw materials. Porous mullite ceramics showed different microstructures depending on their starting materials. The specimen M2 had excellent resistance to thermal spalling and high mechanical strength. The average pore size varied from 0.3 ${\mu}{\textrm}{m}$ to 16.6 ${\mu}{\textrm}{m}$, and porous mullite ceramics fabricated by thermal decomposition of Al(OH)3 had very large pores and broad distribution of pore size.

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Tracking Capability Analysis of ARGO-M Satellite Laser Ranging System for STSAT-2 and KOMPSAT-5

  • Lim, Hyung-Chul;Seo, Yoon-Kyung;Na, Ja-Kyung;Bang, Seong-Cheol;Lee, Jin-Young;Cho, Jung-Hyun;Park, Jang-Hyun;Park, Jong-Uk
    • Journal of Astronomy and Space Sciences
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    • v.27 no.3
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    • pp.245-252
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    • 2010
  • Korea Astronomy and Space Science Institute (KASI) has developed a mobile satellite laser ranging (SLR) system called ARGO-M since 2008 for space geodesy research and precise orbit determination technologies using SLR with mm level accuracy. ARGO-M is capable of night tracking and daylight tracking for which requires spatial, spectral and time filters due to high background noises. In this study, characteristics and specifications of ARGO-M are discussed and its tracking capabilities of night and daylight tracking are analyzed for STSAT-2B and KOMPSAT-5 through link budget. Additionally false alarm and signal detection probabilities are also analyzed depending on spectral and time filters for daylight tracking for these satellites.

Performance of CQUEAN camera

  • Choi, Chang-Su;Park, Won-Kee;Jeon, Yi-Seul;Pak, Soo-Jong;Im, Myung-Shin
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.63.1-63.1
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    • 2010
  • CQUEAN (Camera for QUasars in EArly uNiverse) is a newly developed camera system by CEOU optimized at 0.8 - $1.1{\mu}m$ wavelength region. From Aug. 10 to Aug. 17, 2010, the camera was installed at 2.1m Otto Struve telescope at McDonald Observatory, USA, and engineering test observation was performed. We obtained the data for the characteristics of camera and scientific purpose using 7 filters (g, r, i, z, Is, Iz, Y). For the purpose of discovery of z - 5~6 quasar, we specially used new filters (Is,Iz). During the test observation, we obtained the data of Gamma-Ray Burst, high redshift quasars, high redshift quasar candidates and other calibration data. We present general characteristics of the reduced data taken with CQUEAN and show the performance of the camera.

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The characteristics of ceramic filter using energy trapping effect (에너지 트래핑 효과를 이용한 세라믹 필터의 특성에 관한 연구)

  • 박기엽;김원석;송준태
    • Electrical & Electronic Materials
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    • v.8 no.2
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    • pp.144-150
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    • 1995
  • Ceramic filter using energy trapping effect is used bandpass filter at high frequency. In this paper, the resonant points of the symmetrical modes and antisymmetrical modes were theoretically analyed and synthesized these modes in order to know the filter characteristics. We simulated them using the computer and also fabricated the ceramic filter using PZT-4 piezoelectric plate made by Valpey Fisher Co., The 1.5[.mu.m] - thick platinum electrode were deposited on the ceramic plates with the various masks. The characteristics of the fabricated filters were measured using the spectrum analyzer. Experimental data were compared with the theoretical results. The maximum-pass frequencies coinsided exactly. The bandwidths of the fabricated filters were slightly different between theoretical and experimental results. We found that these phenomenon were caused by the stray capacitance between the two neighbor electrodes..

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A Study on Dynamic Separation of Silica Slurry Using a Rotating Membrane Filter: Transient State and Steady State (회전막 여과기를 사용한 실리카 슬러리의 동역학적 분리에 대한 연구: 과도기와 정상 상태)

  • 박진용;최창균;김재진
    • Proceedings of the Membrane Society of Korea Conference
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    • 1992.10a
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    • pp.53-54
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    • 1992
  • In this study characteristics of dynamic filters utilizing Taylor vortices were investigated both experimentally and theoretically. With fine silica slurry of 4.0 $\mu$m in average size experiments were conducted in Taylor vortices generated between the rotating inner cylinder consisting of microfiltration membrane of 1.2 $\mu$m in average pore size and the stationary outer cylinder. The diameter of the inner cylinder was 5.2 cm. Four outer cylinders having different diameters were manufactured and therefore four types of dynamic filters having the different ratio of the annular gap to the inner cylinder radius, i.e. 0.17, 0.33, 0.54, 0.65, were used as the experimental apparatus, as shown in Fig. 1.

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A CMOS Analog Front End for a WPAN Zero-IF Receiver

  • Moon, Yeon-Kug;Seo, Hae-Moon;Park, Yong-Kuk;Won, Kwang-Ho;Lim, Seung-Ok;Kang, Jeong-Hoon;Park, Young-Choong;Yoon, Myung-Hyun;Yoo, June-Jae;Kim, Seong-Dong
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.769-772
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    • 2005
  • This paper describes a low-voltage and low-power channel selection analog front end with continuous-time low pass filters and highly linear programmable-gain amplifier(PGA). The filters were realized as balanced Gm-C biquadratic filters to achieve a low current consumption. High linearity and a constant wide bandwidth are achieved by using a new transconductance(Gm) cell. The PGA has a voltage gain varying from 0 to 65dB, while maintaining a constant bandwidth. A filter tuning circuit that requires an accurate time base but no external components is presented. With a 1-Vrms differential input and output, the filter achieves -85dB THD and a 78dB signal-to-noise ratio. Both the filter and PGA were implemented in a 0.18um 1P6M n-well CMOS process. They consume 3.2mW from a 1.8V power supply and occupy an area of $0.19mm^2$.

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System Development and IC Implementation of High-quality and High-performance Image Downscaler Using 2-D Phase-correction Digital Filters (2차원 위상 교정 디지털 필터를 이용한 고성능/고화질의 영상 축소기 시스템 개발 및 IC 구현)

  • 강봉순;이영호;이봉근
    • Journal of the Institute of Convergence Signal Processing
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    • v.2 no.3
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    • pp.93-101
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    • 2001
  • In this paper, we propose an image downscaler used in multimedia video applications, such as DTV, TV-PIP, PC-video, camcorder, videophone and so on. The proposed image downscaler provides a scaled image of high-quality and high-performance. This paper will explain the scaling theory using two-dimensional digital filters. It is the method that removes an aliasing noise and decreases the hardware complexity, compared with Pixel-drop and Upsamling. Also, this paper will prove it improves scaling precisians and decreases the loss of data, compared with the Scaler32, the Bt829 of Brooktree, and the SAA7114H of Philips. The proposed downscaler consists of the following four blocks: line memory, vertical scaler, horizontal scaler, and FIFO memory. In order to reduce the hardware complexity, the using digital filters are implemented by the multiplexer-adder type scheme and their all the coefficients can be simply implemented by using shifters and adders. It also decreases the loss of high frequency data because it provides the wider BW of 6MHz as adding the compensation filter. The proposed downscaler is modeled by using the Verilog-HDL and the model is verified by using the Cadence simulator. After the verification is done, the model is synthesized into gates by using the Synopsys. The synthesized downscaler is Placed and routed by the Mentor with the IDEC-C632 0.65${\mu}{\textrm}{m}$ library for further IC implementation. The IC master is fixed in size by 4,500${\mu}{\textrm}{m}$$\times$4,500${\mu}{\textrm}{m}$. The active layout size of the proposed downscaler is 2,528${\mu}{\textrm}{m}$$\times$3,237${\mu}{\textrm}{m}$.

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Simultaneous Removal of NOx/SOx by Catalyst-loaded Cordierite Porous Filter (촉매 담지 코디어라이트 다공성 필터의 NOx/SOx 동시제거에 대한 연구)

  • Lee, Shi-Hee;Chung, Koo-Chun;Kim, Jee-Woong;Shin, Min-Chul;Lee, Hee-Soo
    • Analytical Science and Technology
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    • v.15 no.3
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    • pp.256-262
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    • 2002
  • After porous filters were manufactured using cordierite powder whose mean paricle size was 200${\mu}m$, they were loaded with catalysts such as $V_2O_5$, CuO and $LaCoO_3$ by vacuum impregnation method. And the NOx/SOx simultaneous removal efficiency was measured by passing NO and $SO_2$ through catalyst-loaded ceramic filters. The cordierite porous filters had the apparent porosity of 61.6%, the compressive strength of 12.3 MPa and the pressure drop of 147 pa at the face velocity of 5 cm/sec. According to the analysis of NO/$SO_2$ simultaneous removal efficiency, perovskite $LaCoO_3$ catalyst was the most efficient for the simultaneous NO and $SO_2$ removal. The $LaCoO_3$ catalyst-loaded filter could remove more than 90% for NO and more than 80% for $SO_2$.

HTS high gradient magnetic separator prototype

  • Diev, D.N.;Lepehin, V.M.;Makarenko, M.N.;Polyakov, A.V.;Shcherbakov, V.I.;Shutova, D.I.;Surin, M.I.;Tagunov, E. Ya.
    • Progress in Superconductivity and Cryogenics
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    • v.20 no.4
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    • pp.1-5
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    • 2018
  • A high gradient magnetic (HGM) separator prototype with the $2^{nd}$ generation high temperature superconducting (2G HTS) magnetic system operated in sub-cooled nitrogen is presently under development at NRC "Kurchatov Institute" (Moscow, Russia). The main goal of the project is an attempt to shift away from the complicated liquid helium cryostats towards simple cryocooler-based nitrogen cryogenics as much more convenient for HGM separators industrial applications. Using of commercial HTS tapes allows to get a sufficient level of magnetic fields and extraction forces with low energy consumption. The expected operational parameters of the device are 1.2-1.5 T in the empty operational gap and up to 3 T on the ferromagnetic filters. In this paper we briefly describe the design of the HTS rotary separator prototype with the horizontally oriented rotor axis and propose different types of ferromagnetic filters intended for weakly magnetic ores enrichment.