• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.8
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• pp.68-73
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• 2010

In this paper, a compact Ultra-Wideband band-pass filter with notched band at 5.8GHz by using LC resonator is proposed. The structure of the proposed band-pass filter is very simple, and the DGS(Defected Ground Structure) is used to get the low-pass filter characteristics and the LC resonator is used to get the notched filter. The proposed band-pass filter can be much smaller than a cascaded filter type. The LC resonator is designed with a radial stub and small stub. As a result of measurement, the insertion loss is less than 0.5dB throughout the pass-band of 2.21GHz~10.92GHz, the return loss is more than 16dB and the maximum variation of group delay is 0.29ns and a notched band is 5.2GHz~6.2GHz.

• Journal of the Korean Chemical Society
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• v.18 no.3
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• pp.180-188
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• 1974

Adsorption mechanism of alkyl aldehydes, acetaldehyde, acrolein, and crotonaldehyde on cations supported by layer silicates was studied by means of IR spectroscopy and X-ray. An analysis of four characteristic split bands in the region of $1720∼1580㎝^{-1}$ was made. The carbonyl stretching band which shifted about $130㎝^{-1}$ to lower frequencies was observed only for $Ni^{2+}$ and Al^{3+}$ but slightly with $Ca^{2+}$ at high sample temperature and was attributed to >C=O…M complex formation. A sharp band which appeared as a shoulder at 1722 for acetaldehyde and 1690 for acrolein and crotonaldehyde was responsible for the interaction of carbonyl with surface hydroxyl. The second broad band which appeared at about 1710~1660 was responsible for hydrogen bonding between carbonyl oxygen and cationic hydroxyl group. The third band which appeared at about 1640~1660 was attributed to induced >C=C< double bond due to the strong carbonyl interaction. This was supported by the interlamellar spacings obtained by X-ray diffractometry.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.7
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• pp.65-70
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• 2012

In this paper, a compact UWB (Ultra Wideband) BPF(Band-Pass Filter) with dual notched bands is proposed using a hybrid Composited Right-Left Handed (CRLH) and Defected Ground Structure (DGS). To avoid the interferences such as Wireless LAN (Center frequency: 2.4GHz and 5.8GHz), the CRLH is employed to obtain the dual notched bands and the DGS is used to obtain the wide stop-band above the pass-band. The fabricated filter has good performance and has more than 30dB rejection at the center frequency of 2.4 GHz and 5.8GHz. The dual notched bands are easily movable by changing the CRLH parameter. Also the insertion loss is less than 0.4dB in the lower pass-band and 0.7dB in the upper pass-band, and it has small group delay variation less than 0.6ns. The size of the fabricated filter is very compact (17mm*17mm).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.66-69
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• 2016

In this paper, we suggests a Ka-band LNB considering next-generation UHD satellite TVRO. Since Ka-band has grater attenuation than Ku-band in atmosphere, we designed the low-noise down-converter to improve receiving sensitivity and to extend a dynamic range of receiver. It aims to compensate a quality of ultra high definition transmission signal for rainfall. The low-noise block diagram consists of a three-staged amplifier (LNA), band-pass filter for deleting image (BPF), mixer and IF when considering nonlinear characteristics in the receiver RF front end module. Also, we showed a LNB through optimization processes affecting dynamic range directly in receiver FEM. Asa resuly of experiment, the gain of low-noise down-converter show between 58.5dB and 60.7dB, the noise figure has a high characteristic as 1.38dB. Finally, the phase noise of local oscillator is -63.10dBc at 100MHz offset frequency.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.3
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• pp.22-28
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• 2017

In modern electronic warfare, a variety of devices are being operated in the fields for the purposes of communication and surveillance. Therefore, if such devices work in the same band, interference may occur and affect each other. Regarding L-band in which various devices including radar systems are operating, interference from existing devices may affect new ones in the band. In this paper, we estimate a probability distribution of the interference environment in L-band from the selected measurement data, which is fundamental for the mathematical analysis. After selecting the candidates of probability distribution, we suggest the best one from the group. The results of this study are expected to be utilized as fundamental data for the mathematical approach to the L-band interference environment.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.828-831
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• 1999

5,15-Bis(mesityl)-10,20-bis(4-amino)porphyrin was synthesized with meso-(mesityl)dipyrromethane and 4-nitrobenzaldehyde. It was characterized with $^1H$-NMR spectroscopy, UV spectrophotometer, and GC-MASS. In UV spectrum, Soret-band(438 nm) and Q-bands(526, 572, 611 nm) were confirmed. In NMR spectrum, the characteristic peak of porphyrin was detected at -2.65 ppm. Copolyimide containing porphyrin structure was synthesized with mesityl-$TPP(NH_2)$, 3,3',4,4'-benzophenonetetracarboxylic dianhydride(BTDA) and 2,2-bis(4-(4-aminophenoxy)phenyl) hexafluoropropane(BAPHF) and characterized with UV and FT-IR spectrophotometer. The $T_g$ and $T_m$ of the synthesized copolyimide were 220.7 and $369.2^{\circ}C$, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1423-1431
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• 2010

In this paper, the dual-band compact broad bandpass filter using parallel coupled line is proposed. The proposed filter has reduced size and can be controlled bandwidth. And it is also possible to operate in the dual-band purpose. Futhermore, the inserted bandstop fiilter with T-type configuration is also possible to operate in the same purpose. The dual-band bandpass filter has the first operating frequencies and its bandwidth which are 5.8 GHz and 60 % respectively and the second operating frequency and the bandwidth are 16.2 GHz and 60 % respectively. The insertion loss and the return loss of the first frequency has 0.4 dB and 17.4 dB and the insertion loss and the return loss of the second frequency has 0.62 dB and 19.8 dB, respectively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.1-6
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• 2017

Recently, the brittle materials such as ceramics, glass, sapphire and textile material have been widely used in semiconductors, aerospace and automobile owing to high functional characteristics. On the other hand, it has the characteristics of difficult-to-cut material relative to all materials. In this study, diamond electro-deposited band-saw machine was developed to operate stably using water-coolant type through relative motion between band-saw tool and $Al_2O_3$ material. High densified $Al_2O_3$ material was manufactured by spark plasma sintering method. The bulk density was observed by the Archimedes law and the theoretical density was estimated to be $3.88g/cm^3$ and its hardness 14.7 MPa. From the dicing sawing test of $Al_2O_3$ specimen, behavior of surface roughness and band-saw wear are dominantly affected by the increase of the band-saw linear velocity. Additionally, an continuous pattern type of diamond band-saw was a very effective due to entry impact as a one-off for brittle material.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2009.03a
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• pp.161-161
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• 2009

To prevent distraction and varus deformity between the humeral head and shaft, tension band sutures placed between the head of the interlocking screw and the rotator cuff, and we recommend using nonabsorbable sutures. We describe our simple procedure to overcome these difficulties in tension band suturing after reducing a proximal humerus fracture to maintain the reduction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.66-66
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• 2009

The photoconductive $CdGa_2Se_4$ layer was grown through the hot wall epitaxy method. From the photocurrent (PC) measurements, the three peaks in the PC spectra were associated with the band-to-band transitions. The PC intensities were observed to decrease with decreasing temperature. The valence-band splitting on $CdGa_2Se_4$ was also observed by means of the PC spectroscopy. The crystal field splitting and the spin orbit splitting turned out to be 0.1604 and 0.4179 eV at 10 K, respectively.