• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.216-222
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• 2006

In this paper, we investigated the effect of hydrogen-plasma (H-plasma) treatment on the electrical and optical properties of a quantum dot infrared photodetector (QDIP) with a 5-stacked InAs dots in an InGaAs/GaAs well structure and $Al_{0.3}Ga_{0.7}As/GaAs$ SL (superlattice) current blocking layer. It has been observed that H-plasma treatment didn't affect the band structure of QDIP. It has been also observed that the H-plasma treatment on the QDIP not only enhance the electrical property of QDIP by curing the defect channels in $Al_{0.3}Ga_{0.7}As/GaAs$ SL but also introduce defects in QDIP structure. The H-plasma treatment for 10 min with 20 W of RF power provided the lowest dark current, which made it possible to measure the photo-current (PC) of QDIP whose PC was not detectable without the H-plasma treatment due to the high dark current.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.10
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• pp.841-850
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• 2015

With the rapid progress of electronics and radio communication technology, human enjoys greater freedom in information communication. However, EMW(Electro-Magnetic Wave) environments have become more complicate and difficult to control. Thus, international organizations, such as the American National Standard Institution(ANSI), Federal Communications Commission(FCC), the Comite Internationale Special des Perturbations Radio Electrique(CISPR), etc, have provided standard for controlling the EM wave environments and for the countermeasure of the electromagnetic compatibility(EMC). In this paper, fabrication of the smart EMW absorber which has heat radiating function and high performance absorption abilities were suggested. Furthermore, we prospected future smart EMW absorbers. The designed smart EMW absorber is fabricated following process. Firstly, we applied high temperature heat treated to a mixture of Iron-oxide($Fe_2O_3$) and ceramics. Secondly, we applied low temperature heat treated to the mixture of heat treated material and a carbon material. Lastly, we made apertures on the absorber. The designed smart EM wave absorber has the absorption ability of more than 20 dB from 2 GHz to 2.45 GHz band, respectively. Thus, it is respected that these results can be applied as various EMC devices in electronic, communication, and controlling systems.

• Korean Journal of Animal Reproduction
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• v.16 no.4
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• pp.289-299
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• 1993

The polypeptide patterns of cellular and follicular components were analysed by SDS-PAGE and two dimensional(2-D)electrophoresis combined with isoelectric focusing (IEF) to establish protein profiles in each of the components in porcine follicles. Oocyte-cumulus complexes were cultured in M16+FCS+Gn at 39 in an atmosphere of 5% CO$_2$, in air for 35 h. At the end of the culture, the zona-free oocyte, ZP alone and cumulus cells were prepared and analysed either on 10% SDS-PAGE for the protein profile at the first dimensional gel or 2-D protein pattern. The amounts of each samples were determined for the visualization with Coomasie brilliant blue (CBB) or silver staining, thus giving useful information for the identification of specific proteins in the components or appropriate amount of samples for proper visualization. Oocyte showed 25 and 114 kd major protein band. Other minor components were additionally visualized with CBB on the same gel after silver staining procedure. Cumulus cells also showed specific proteins which is not present in the oocytes. The number of cumulus cell was proper to give major bands with CBB and additional minor bands with silver staining. To establish the degree of contamination from the remnant of the corona radiata to the ZP, zonae were differently prepared or analysed by SDS-PAGE.The preparation of the ZP in this study did not showed any contamination judged by the protein profile of the components. Also follicular fluid showed its specific protein profile without any significant differences among the different sizes of follicles. The established protein profile of each follicular component should be helpful for the identification and elimination of contaminated components, i. e., antigen preparation or immunological studies. The results also suggest that the preparation of each components in the study was appropriate and can be used for a further sensitive biochemical analysis in mammalian oocytes and early embryos.

• Conservation Science in Museum
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• v.10
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• pp.43-61
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• 2009

The Buyeo National Museum was requested conservation treatment for wooden objects excavated from three Baekje archeological sites: Neungsan-ri, Ssangbuk-ri, and Gungnamji Pond. Prior to conservation treatment, analysis was conducted to identify the species used. The results of the analysis revealed wood from diverse species of trees including Hard pine, Cryptomeria japonica D. Don, Zelkova serrata Makino, Quercus spp., Platycarya strobilaceae S. et Z., Castanea spp., Torreya nucifera S. et Z., Taxus cuspidata S. et Z., and Salix spp. A high percentage of the objects were made of Cryptomeria japonica D. Don., a species native to Japan, which indicates that exchange with Japan was active at that time. Among the wooden objects, we analyzed lacquer fragments from six pieces of lacquerware, and the characteristics of the lacquer fragments were peculiar to specific artifacts. Most of the fragments were thicker than 100 ㎛. Pure lacquer and mixed black pigment were used. Infrared spectroscopy of the lacquered wooden fragments revealed that they had a very similar absorption band as refined lacquer, confirming that they were painted with lacquer. For their conservation, we immersed the objects in a high molecular weight aqueous solution of PEG#3,350 (10% → 50%) to strengthen them before vacuum freeze-drying.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.36-41
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• 2018

This paper presents an implementation of a millimeter-wave(W band) multiflare-angle horn antenna. The proposed antenna is a multimode dual-polarized square horn having equal E- and H-plane beamwidths and consists of a multimode generating section, a four-square-waveguide exciter, orthomode transducers, and power combiners for the sum pattern formation. The antenna structure has been designed to allow for easy fabrication and the designed antenna has been fabricated to a precision of ${\pm}0.02mm$ by layer-by-layer machining and diffusion bonding. The input reflection coefficient and the radiation pattern of the fabricated antenna have been measured using a network analyzer and a far-field test facility. Measurements show that the proposed antenna has 17.7~18.3 dBi gain, $25.2{\sim}28.5^{\circ}$ beamwidth, and an input VSWR between 1.02~1.75, within ${\pm}0.5GHz$ from the center frequency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1407-1413
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• 2006

The field of medical images has been digitalized as the development of computer and the digitalization of the medical instruments. As a result it causes a lot of problems such as an illegal copy related to medical images and property right of the medical images. Therefore, digital watermarking is used for discrimination whether the data are modified or not. It is also used to protect both the property right of medical images and the private life of many patients. The proposed theories, the Non-blind and the Blind method, have two problems. One is needed an original image and the other is using a gaussian watermarking. This paper proposes the new Blind Watermarking using binary images in order to easily recognize the results of watermark. This algorism is described that an watermark of a binary image is wavelet-transformed, and then a transformed watermark is inserted in medium-band of frequency domains of original image by the Circular Input method. This method don't have any loss when image didn't have any attack. As a result Watermark can be perfectly extracted by using this algorithm. And Maximam PSNR value is improved 3.35dB. This algorithm will be improved by using gray level image and color image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2151-2156
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• 2006

Beamforming for underwater acoustic communication (UAC) is affected by the broadband feature of UAC signal, which has relatively low currier frequency as compared to the signal bandwidth. The narrow-band assumption does not hold good in UAC. In this paper, we discuss a broadband FIR beamformer for UAC using the baseband equivalent way signal model. We consider the broadband FIR beamformer for QPSK UAC with carrier frequency 25kHz and symbol rate 5kHz. Array geometry is a uniform linear way with 8 omni-directional elements and sensor spacing is the half of the carrier wavelength. The simulation results show that the broadband n beamformer achieves nearly optimum signal to interference and noise ratio (SINR) and outperforms the conventional narrowband beamformer by SINR 0.5dB when two-tap FIR filter is employed at each sensor and the inter-tap delay is a quarter of the symbol interval. The broadband FIR beamformer performance is more degraded as the FIR filter length is increased above a certain value. If the inter-tap delay is not greater than half of the symbol period, SINR performance does not depend on the inter-tap delay. More training period is required when the inter-tap delay is same as the symbol period.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.1-7
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• 2008

The paper is to solve the problem of existing sound system, which has difficulties of system organization and the increase of additional install cost and unfriendly interior. To solve the existing system, we drew the new sound system based on PLC and studied it. A transmitter and a receiver were designed using the PLC chip INT5500CS. Sound system was configured with a CD player that sound signals are sent from the transmitter and a speaker connected to the receiver. For analysis of characteristics of this system, a USBPre external sound card and Smaart Live 5 which is a PC-based sound measuring program were added. As a result of our experiment, the measured signal level is $2{\sim}3$[dB] lower than reference signal, latency is 16.69[ms] and the specific character of coherency is bad in high frequency band. Otherwise, this system transmits and receives signals over 90[%] in good condition as a result of measuring pink noise, frequency(1kHz), and phase, magnitude. In view of the result so far achieved, the system designed our team has excellent performance, it resolves defect of existing audio signal transmition system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5796-5800
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• 2014

This paper presents reconfigurable beam steering patch antenna with high gain for a wireless headset. Because existing antenna for wireless communication in headsets has an omni-directional radiation pattern, it has a deleterious effect in the vicinity of the human head. To reduce this effect, this paper proposed an antenna comprised of a U-slot and manufactured on a FR-4 substrate. The antenna operating at the 2.37-2.5 GHz band used a tapered matching method to match the impedance between the feed part and patch part. To implement the beam steering capability, the antenna used two PIN diodes. Using PIN diodes, the antenna presented three states ($S_0$, $S_1$ and $S_2$) in the maximum beam directions of the YZ-plane ($0^{\circ}$, $30^{\circ}$ and $330^{\circ}$, respectively). The peak gains of the antenna in the headset were 4.22-5.15 dBi. The fabricated antenna could communicate efficiently with a wireless headset.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.150-157
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• 2006

Spatially resolved remote identification and quantification of trace gases in the atmosphere is desirable in various fields of scientific research as well as in public security and industrial contexts. Environmental observations investigating causes, extent md consequences of air pollution are of fundamental interest. We present an Imaging-DOAS system, a ground based remote sensing instrument that allows spatially resolved mapping of atmospheric trace gases by a differential optical absorption spectroscopy(DOAS) with sun scattered light as the light source. A passive DOAS technique permits the identification and quantification of various gases, e.g., $NO_2,\;SO_2,\;and\;CH_2O$, from their differential absorption structures with high sensitivity. The Imaging-DOAS system consists of a scanning mirror, a focusing lens, a spectrometer, a 2-D CCD, ad the integral control software. An imaging spectrometer simultaneously acquires spectral information on the incident light in one spatial dimension(column) and sequentially scans the next spatial dimension with a motorized scanning mirror. The structure of the signal acquisition system is described in detail and the evaluation method is also briefly discussed. Applications of imaging of the $NO_2$ contents in the exhaust plumes from a power plant are presented.