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Pitch Measurement of 150 ㎚ 1D-grating Standards Using an Nano-metrological Atomic Force Microscope
Jonghan Jin,Ichiko Misumi,Satoshi Gonda,Tomizo Kurosawa 한국정밀공학회 2004 International Journal of Precision Engineering and Vol.5 No.3
Pitch measurements of 150 ㎚ one-dimensional grating standards were carried out using a contact mode atomic force microscopy with a high resolution three-axis laser interferometer. This measurement technique was named as the 'nano-metrological AFM'. In the nano-metrological AFM, three laser interferometers were aligned precisely to the end of an AFM tip. Laser sources of the three-axis laser interferometer in the nano-metrological AFM were calibrated with an I2-stabilized He-Ne laser at a wavelength of 633 ㎚. Therefore, the Abbe error was minimized and the result of the pitch measurement using the nano-metrological AFM could be used to directly measure the length standard. The uncertainty in the pitch measurement was estimated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM). The primary source of uncertainty in the pitch-measurements was derived from the repeatability of the pitch-measurements, and its value was about 0.186 ㎚. The average pitch value was 146.65 ㎚ and the combined standard uncertainty was less than 0.262 ㎚. It is suggested that the metrological AFM is a useful tool for the nano-metrological standard calibration.
Efficient Storage Scheme for Microarray Data using Structural Similarity
Jonghan Yun,Dongkyoo Shin,Dongil Shin,Sanghoon Song 대한전자공학회 2008 ICEIC:International Conference on Electronics, Inf Vol.1 No.1
As one of typical techniques for acquiring bioinformation, gene microarray was solidly entrenched. However microarray experiments create very complex and huge amount of data and many researchers were being pinched at managing microarray data. Microarray was standardized by MGED group and MAGE-ML is established as a format expressed for MAGE-OM by XML. As establishing this standard, database design for microarray data has gained interest in bioinformatics area. However it has no consideration for efficient storage construction. In this paper, we propose strategies that efficiently convert complex structure of MAGE-ML into relatively compact structure in RDBMS based on the structural similarity of MAGE-ML element. The model induces fewer numbers of joins from database.
Use of Remotely-Sensed Data in Cotton Growth Model
Jonghan Ko,Stephan J. Maas 韓國作物學會 2007 한국작물학회지 Vol.52 No.4
Remote sensing data can be integrated into crop models, making simulation improved. A crop model that uses remote sensing data was evaluated for its capability, which was performed through comparing three different methods of canopy measurement for cotton(Gossypium hirsutum L.). The measurement methods used were leaf area index(LAI), hand-held remotely sensed perpendicular vegetation index(PVI), and satellite remotely sensed PVI. Simulated values of cotton growth and lint yield showed reasonable agreement with the corresponding measurements when canopy measurements of LAI and hand-held remotely sensed PVI were used for model calibration. Meanwhile, simulated lint yields involving the satellite remotely sensed PVI were in rough agreement with the measured lint yields. We believe this matter could be improved by using remote sensing data obtained from finer resolution sensors. The model not only has simple input requirements but also is easy to use. It promises to expand its applicability to other regions for crop production, and to be applicable to regional crop growth monitoring and yield mapping projects.
Absolute Distance Measurements Using the Optical Comb of a Femtosecond Pulse Laser
Jonghan Jin,Young-Jin Kim,Yunseok Kim,Seung-Woo Kim 한국정밀공학회 2007 International Journal of Precision Engineering and Vol.8 No.4
We describe a new way of implementing absolute displacement measurements by exploiting the optical comb of a femtosecond pulse laser as a wavelength ruler. The optical comb is stabilized by locking both the repetition rate and the carrier offset frequency to an Rb clock of frequency standard. Multiwavelength interferometry is then performed using the quasi-monochromatic beams of well-defined generated wavelengths by tuning an external cavity laser diode consecutively to preselected light modes of the optical comb. This scheme of wavelength synthesizing allows the measurement of absolute distances with a high precision that is traceable to the definition of time. The achievable wavelength uncertainty is 1.9×<SUP>-10</SUP>, which allows the absolute heights of gauge blocks to be determined with an overall calibration uncertainty of 15 nm (k = 1). These results demonstrate a successful industrial application of an optical frequency synthesis employing a femtosecond laser, a technique that offers many possibilities for performing precision length metrology that is traceable to the well-defined international definition of time.
Simulation for Irrigation Management of Corn in South Texas
Jonghan Ko,Giovanni Piccinni 韓國作物學會 2008 Korean journal of crop science Vol.53 No.2
Interest is growing in applying simulation models for the South Texas conditions, to better assess crop water use and production with different crop management practices. The Environmental Policy Integrated Climate (EPIC) model was used to evaluate its application as a decision support tool for irrigation management of com (Zea mays L.) in South Texas of the U.S. We measured actual crop evapotranspiration (ETc) using a weighing lysimeter, soil moisture using a neutron probe, and grain yield by field sampling. The model was then validated using the measured data. Simulated ETc using the Hargreaves-Samani equation was in agreement with the lysimeter measured ETc. Simulated soil moisture generally matched with the measured soil moisture. The EPIC model simulated the variability in grain yield with different irrigation regimes with r2 value of 0.69 and root mean square error of 0.5~;ton~;ha-1 . Simulation results with farm data demonstrate that EPIC can be used as a decision support tool for com under irrigated conditions in South Texas. EPIC appears to be effective in making long term and pre-season decisions for irrigation management of crops, while reference ET and phenologically based crop coefficients can be used for inseason irrigation management.
Chemical and Physical Characteristics of Expanded Rice Husk Medium on Growth of Rice Seedling
Jonghan Ko,Jin Kwan Ham,Yong Bok Kim,Kyung Hee Kim,Byun Woo Lee,Youn Su Lee 韓國作物學會 2005 Korean journal of crop science Vol.50 No.2
Expanded rice husk (ERR) is different from commercial rice seedling media in chemical and physical properties such as pH, permeability, and water content. This study was conducted to test a possibility of improving rice seedling growth by improving the texture of ERR as a rice seedling medium. The seedling media used were a commercial seedling medium (CSM), rice husk, and ERR 1, 2, 3, and 4 with different expansion degrees. The pH of the ERHs ranged from 6.3 to 6.8. As the expansion rate increased, ERR particle sizes decreased, and water permeability and absorption rates improved. No significant differences in shoot dry weight and rate of maturity were found among the seedlings cultivated in the different ERH media. However, the mat formation of seedling roots became loose as the expansion rates were decreased. Further studies are necessary to determine the cause of poor root growth in ERH media.
Efficient Cooling Method for a Cu Coil in an Induction Cooker by Using an Insulation Sheet
Jonghan Kwon,Yoon Jae Nam,K. H. Shin,S. H. Lim 한국자기학회 2011 Journal of Magnetics Vol.16 No.1
A silica aerogel sheet with a very low thermal conductivity is used to suppress the temperature increase of the Cu coil in an induction cooker by reducing the heat flow from the heat source (cooking pot). It is found that the temperature of the Cu coil is reduced significantly by the insertion of an insulation sheet between the heat source and the Cu coil, demonstrating the effectiveness of the insulation sheet in the suppression of the heat flow between the cooking pot and the coil. Furthermore, the temperature of the cooking pot increases more rapidly with the use of the insulation sheet, allowing for an increased efficiency of the induction cooker.