• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.151-154
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• 1999

ZnO thin films on glass substrate were deposited by RF magnetron reactive sputter with various argodoxygen gas ratios and substrate temperatures. Crystallinities, surface morphologies, chemical compositions, and electrical properties of the films were investigated by XRD, SEM, XPS and electrometer(keith1ey 617). All films showed a strong prefered orientation along the c-axis on glass substrate, and the chemical stoichiometry was obtained at Ar/$O_2$=50/50. The propagation velocity of ZnO SAW filter was about 2, 590 dsec and insertion loss was a minimum value of about -21dB.

• 한국재료학회지
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• 제14권7호
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• pp.470-476
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• 2004

The fail safety filter is an assistant filter element to be mounted in order to intercept the particles leaked when the main filter elements are broken. So it should have two contrary functions of being plugged easily to meet the purpose of dust sealing and a high permeability to save the space. The permeability of the metal filter elements were effectively controlled by the following factor: powder size(53-840 ${\mu}m$) and applied pressure(1000-2000 $kgf/cm^2$), and then the compact were sintered for 1 hour at $1200^{\circ}C$ in vacuum sintering furnace. The sintered metal filters was evaluated for the function of the fail safety filter in an experimental unit. The maximum allowable particle size was 420-840 ${\mu}m$, when a CIP pressure of 1500 $kgf/cm^2$ was applied reveals a permeability of about $1.2{\times}10^{10}m^2$ and pore size of about 60 ${\mu}m$. The metal filter produced with stainless steel powder of 480-840 ${\mu}m$ size, which presented excellent permeability than commercial ceramic filter element and plugged with in 3 minutes with the leak of the maximum particle size less than 3 ${\mu}m$.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2004년도 춘계학술대회 논문집
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• pp.191-193
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• 2004

• 대한설비공학회지:설비저널
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• 제26권1호
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• pp.23-33
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• 1997

• 대한설비공학회지:설비저널
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• 제22권6호
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• pp.398-410
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• 1993

• 한국표면공학회지
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• 제42권5호
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• pp.216-219
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• 2009

A surface acoustic wave (SAW) filter structure was fabricated employing $4{\mu}m$ thick nanocrystalline diamond (NCD) and $2.2{\mu}m$ thick ZnO films on Si wafer. The NCD film was deposited in an $Ar/CH_4$ gas mixture by microwave plasma chemical vapor deposition method. The ZnO film was formed over the NCD film in an RF magnetron sputter using ZnO target and $Ar/O_2$ gas. On the top of the two layers, copper film was deposited by the RF sputter and inter digital transducer (IDT) electrode pattern (line/space : $1.5/1.5{\mu}m$) was defined by the photolithography including a lift-off etching process. The fabricated SAW filter exhibited the center frequency of 1.66 GHz and the phase velocity of 9,960 m/s, which demonstrated that a giga Hertz SAW filter can be realized by utilizing the nanocrystalline diamond thin film.

• 대한공간정보학회지
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• 제24권2호
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• pp.37-46
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• 2016

The difference between definition time of GPS (Global Positioning System) position data and actual display time of car positions on a map could reduce the accuracy of car positions displayed in PND (Portable Navigation Device)-type CNS (Car Navigation System). Due to the time difference, the position of the car displayed on the map is not its current position, so an improved method to fix these problems is required. It is expected that a method that uses predicted future positionsto compensate for the delay caused by processing and display of the received GPS signals could mitigate these problems. Therefore, in this study an analysis was conducted to correct late processing problems of map positions by mapmatching using a Kalman filter with only GPS position data and a RRF (Road Reduction Filter) technique in a light-weight CNS. The effects on routing services are examined by analyzing differences that are decomposed into along and across the road elements relative to the direction of advancing car. The results indicate that it is possible to improve the positional accuracy in the along-the-road direction of a light-weight CNS device that uses only GPS position data, by applying a Kalman filter and RRF.

• Korean Journal of Chemical Engineering
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• 제36권3호
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• pp.356-367
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• 2019

This work presents an advanced and systematic approach to analytically design the optimal parameters of a two parameter second-order internal model control (IMC) filter that satisfies operational constraints on the output process, the manipulated variable as well as rate of change of the manipulated variable, for a first-order plus dead time (FOPDT) process. The IMC parameters are designed to minimize a control objective function composed of the weighted sum of the error between the process variable and the set point, and the rate of change of the manipulated variable, and to satisfy the desired constraints. The feasible region of the constrained IMC control parameters was graphically analyzed, as the process parameters and the constraints varied. The resulting constrained IMC control parameters were also used to find the corresponding industrial proportional-integral controller parameters of a Smith predictor structure.

• 펄프종이기술
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• 제47권6호
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• pp.66-72
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• 2015

This study was conducted to investigate the effects of optical brightening agents (OBA) on the chemical degradation characteristics of paper cellulose during humid heating aging. Three different types of OBAs were applied to a filter paper by dipping it in OBA solutions whose concentrations were controlled to 1% and 2%. The filter papers with an OBA were artificially aged at $80^{\circ}C$ and 65% RH, and the changes in pH of paper and viscosity of cellulose were evaluated. Their functional groups were also analyzed by ATR-FTIR (at-tenuated total reflectance fourier transform infrared spectroscopy). It was found that OBAs influenced the chemical degradation of paper cellulose during humid heating aging. Higher concentration of OBA solutions accelerated the degradation of paper cellulose. Especially, after aging for 12 days, the paper cellulose treated with the tetra-type OBA were the most significantly aged among the three types of OBAs. It was assumed that pH of OBA solutions affected the aging characteristics.

• Plant Resources
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• 제3권1호
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• pp.71-78
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• 2000

Autotoxicity restricts reseeding of new alfalfa(Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments, often requiring up to a year or more. One solution for reducing autotoxicity would be to select germplasms or cultivars with tolerance to the autotoxic chemical(5) and use genetically breeding program. Bioassay of seed germination and early seedling growth was conducted to evaluate autotoxic responses of 3 varieties of alfalfa to the water-soluble extracts(at 4 and 8g/L) from alfalfa ‘Cody’leaf by using agar and filter paper medium in a petri-dish assay. Root length at 5 days after seeding was more sensitive to the extract than was hypocotyl length or seed germination, and was a better parameter of autotoxic effects of alfalfa leaf extracts. Use of an agar medium gave better sensitivity of root length than did use of filter paper. Evaluating tolerance with percent of control was more important indicator than was mean of root length because of significant variation among varieties in root length of control treatment. Bioassay ranked varieties in the following order of tolerance on the basis of relative root length; “Cody” >“ Pioneer 5373” >“ Alfagraze”. Seedling growth from old “Cody” seed was more sensitive to the autotoxic chemical(5) than was that from newly produced seed.