• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.3124-3124
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• 2001

The development and evolution of near infra-red spectroscopic (NIS) calibrations for high-moisture materials is an expensive proposition. Such investment is suspect unless the instrument, or instruments, on which calibrations were developed can be preserved intact or re-standardized as component replacements occurs. The objective of this paper is to detail the changes in performance of a six-year old instrument after maintenance in years five and six resulted in collection of spectral data that was increasingly removed from the calibration population. Calibrations for the analysis of mature sugarcane stalks, a high-moisture material, were developed successfully in 1995 using a broad sample population in terms of genetics, and spectral and temporal variation. The spectral library was further broadened in 1996. In 1997, 1999, 1999, and 2000, additional samples constituting 10% of the laboratories throughput were subjected to full component analyses using routine laboratory techniques. These samples were primarily random samples, but were complemented with samples that were significant for the spectral H statistic or for the component t statistic. In 1998, an additional calibration was developed for populations consisting of samples of either mature stalks (culms) or sucker culms. Substantial additional samples numbers were collected for this calibration in 1999 and 2000. Attempts to standardize the scanning spectrophotometer used for these calibrations with a second similar instrument in 1999 failed because the instruments were optically different, and standardization could not account for this. Maintenance adjustments were made to the remote reflectance probe of the original instrument in 1999, and replacement of its PbS detectors was done in 2000. Spectral data collected in 1999 and 2000 yielded spectral populations that were increasingly removed from the respective spectral populations on which the calibrations were developed. The mature stalk calibrations benefited marginally from evolutionary calib.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1619-1619
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• 2001

Ourwork aims to assess the content of dry matter, protein, cell wall parameters and water soluble carbohydrates in forages without having to handle samples, transport them to a laboratory, dry, grind and chemically analyze them. for this purpose, the concept of fresh forage analysis under field conditions by means of compact integrated NIRS InGaAs-diode array instruments on small plot harvesters is being evaluated for plant breeding trials. This work was performed with the world first commercial experimental forage plot harvester equipped with a NIRS module for the collection, compression, and scanning of forage samples (including automatic referencing and dark current measure ments). It was used for harvesting and analyzing a number of typical forage grass and forage legume plot trials. After NIRS measurements in the field each sample was again analyzed in the laboratory by means of a conventional grating spectrometer equipped with Si-and PbS-detectors. Conventional laboratory analysis of the samples was restricted to dry matter (DM) content by means of oven drying at 105. Routine chemometric procedures were then employed to assess the comparative accuracy and precision of the DM assessments in the spectral range between 950 and 1650nm by the NIRS diode array as well as by the conventional NIRS scanning instrument. The results of this study confirmed that the type of NIRS diode array instrument employed here functioned well even in rugged field operations. further refinements proved to be necessary for optimizing the automatic filling of the sample compartment to adjust for the wide variation in forage material under conditions of extremely low or high harvest yields. The error achieved in calibrating the apparatus for forages of typical DM content proved to be satisfactory (SECV < 1.0). Possibly as a consequence of higher sampling errors, its performance in atypical forages with elevated DM contents was less satisfactory. The error level obtained on the conventional grating NIR spectrometer was similar to that of the diode array instrument for both types of forage.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.1-12
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• 2014

In this paper, we developed an explosion proof type and portable combustible gas leak detector and proposed an algorithm to improve the accuracy for measuring gaseous concentrations. The nation's first we developed an infrared gas leak detector with explosion proof standard(Ex d ib) and improved measuring accuracy by using linearization recursion equation and 2nd Lagrange interpolation polynomial. Together, we advanced their performances and added their easy functions after investigating field demands. To compare our and other company's detectors, we performed measurement tests with eight standard gases made by Korea Gas Safety Corporation. We demonstrated the excellence of our instruments in measuring accuracy other than detecters through experimental results.

• Journal of Astronomy and Space Sciences
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• v.31 no.2
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• pp.177-186
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• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA) detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL) mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.8
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• pp.42-47
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• 2000

Long-wavelength infrared (LWIR) detectors made of self-assembled quantum dots embedded in the channel region of high electron mobility transistor (HEMT) is demonstrated. Above 180 K, the detector shows low dark currents due to strong confinement effect of electrons in InAs quantum dots and exhibits the broad spectral response ranging from 7 mm to 11 mm. The peak detectivity ($D^*$) of $1.93{\times}10^{10}cmHz^{1/2}/W$ is obtained at 9.4 mm. The photocurrent characteristics as a function of applied bias are similar to that of normal FETs, while the photocurrent decreases as the applied electric field exceeds $2{\times}10^3V/cm$ because of the increased dark current.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.48-53
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• 2004

Spectral irradiance measurement system was developed to measure the spectral irradiance of optical sources in the wavelength range from 250[nm] to 1600[nm]. Our system is composed of source system, fore-optics, monochromator system, optical detector system, and automatic control system. Optical detector system with PMT, Si, InGaAs, and IR enhanced InGaAs detectors is used to measure the wide spectrum of optical sources in ultraviolet visible, and infrared wavelength regions. Spectral irradiance of the 1[kW] quartz-halogen tungsten lamp was measured and compared in the wavelength range from 250[nm] to 1600[nm]. The differences between our results and those reported by NIST are below 3[%], 3.5[%], and 5[%] in the wavelength range of 450∼700[nm], 700∼1600[nm], 250∼400[nm], respectively.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.171-172
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• 2008

$(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$ (BSCT) thick films doped with 0.1 mol% $MnCO_3$ and $Yb_2O_3$ ($0.1{\sim}0.7$ mol%) were fabricated by the screen printing method on the alumina substrate. And the structural and electrical properties as a function of $Yb_2O_3$ amount were investigated. The lattice constants of the BSCT thick film doped with 0.1 mol% is 0.3955 nm. The specimen doped with 0.7 mol% $Yb_2O_3$ showed dense and uniform grains with diameters of about 6.3 mm. The thickness of all BSCT thick films was approximately 60 mm. The Curie temperature of the BSCT specimen doped with 0.1 mol% $Yb_2O_3$ was $18^{\circ}C$, and the dielectric constantand dielectric loss at this temperature was 4637 and 4.2%, respectively. The BSCT specimen doped with 0.1 mol% $Yb_2O_3$ showed the maximum value of $349{\times}10^{-9}C/cm^2K$ at Curie temperature. The figure of merit $F_D$ for specific detectivity of the specimens doped with 0.1 mol% $Yb_2O_3$ showed the highest value of $10.9{\times}10^{-9}Ccm/J$.

• Journal of the Optical Society of Korea
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• v.16 no.3
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• pp.243-246
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• 2012

An off-axis four-mirror-anastigmatic telescope is presented here which is composed of two aspheric surfaces and two spherical surfaces. The entrance pupil diameter is 290 mm and the stop is located at the primary mirror. The effective focal length is 900 mm. The strip field of view for the telescope is $15^{\circ}{\times}0.2^{\circ}$ and if the telescope is launched into an orbit about 400 km altitude, the observed range width will be more than 105 km within a scene without any other auxiliary scanning instrument. The spectral range can be as wide as from visual wave band to infrared wave band in the mirror system. This telescope can be used for environmental monitoring with different detectors whose pixel is adapted to the optical resolution. In this paper, the spectral range is chosen as 3.0 -5.0 ${\mu}m$, and center distance of the pixel is 30 ${\mu}m$. And the image quality is near the diffraction limit.

• Korean Journal of Acupuncture
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• v.27 no.2
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• pp.159-181
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• 2010

Objectives : The purpose of this study is to introduce and examine the possibilities of infrared (IR) imaging, biophoton detection and gas discharge visualization(GDV) as diagnostic tools in Korean Medicine. Methods : To review the basic mechanism and measurement methods of three modalities, concepts in physics were introduced. Physical backgrounds of IR, biophoton and GDV were briefly explained based on recent research papers. Simple electronics was employed for relevant detectors. In order to find the relation between Korean Medicine and these methods, papers on their applications were reviewed. Opinions from the experts on each modality were obtained from their papers and private communications. Results and Conclusions : IR imaging has been used as an auxiliary diagnostic tool but there are some rooms for the improvement for clinical applications. Experimental confirmation of the meridian activation by a moxa cigar is necessary for its verification. Biophoton is not correlated with human skin temperature but it has a circadian rhythm. Biophoton and GDV have a negligible relation if any. Therefore there are no correlations among three modalities in terms of basic mechanisms. But their clinical relations are yet to be scrutinized. Biophoton and GDV need more rigorous clinical tests before they can be used as diagnostic tools.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.2
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• pp.27-32
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• 2008

A current research basically diverted towards an increase in the operational output with the minimization of the materials used, which ultimately scaled down the dimensions of ceramic electronic components. In this direction the nano-technology pave the revolutionary changes in particular the electronic industries. The applications of nano-sized particles or nano-sized materials are hence, playing a significant role for various purposes. The PZT(lead, zirconium, titanium) based ceramics which, are reported to be ferroelectric materials have their important applications in the areas of surface acoustic waves (SAW), filters, infrared detectors, actuators, ferroelectric random access memory, speakers, electronic switches etc. Moreover, these PZT materials possess the large electro mechanical coupling factor, large spontaneous polarization, low dielectric loss and low internal stress etc. Hence, keeping in view the unique properties of PZT piezoelectric ceramics we also tried to synthesize indigenously the small sized PZT ceramic powder in the laboratory by using the modified sol-gel approach. In this paper, propyl alcohol based sol-gel method was used for preparation of PZT piezoelectric ceramic. The powder obtained by this sol-gel process was calcined and sintering to reach a pyrochlore-free crystal phase. The characterization of synthesized material was carried out by the XRD analysis and the surface morphology was determined by high resolution scanning electron microscopy.