• Carbon letters
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• v.15 no.3
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• pp.198-202
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• 2014

Amorphous agglomerates of carbon nanospheres (CNS) with a diameter range of 10-50 nm were synthesized using the solution combustion method. High-resolution transmission electron microscopy (HRTEM) revealed a densely packed high surface area of $SP^2$-hybridized carbon; however, there were no crystalline structural components, as can be seen from the scanning electron microscopy, HRTEM, X-ray diffraction, Raman spectroscopy, and thermal gravimetric analyses. Electrochemical and thermo catalytic decomposition study results show that the material can be used as a potential electrode candidate for the fabrication of energy storage devices and also for the production of free hydrogen if such devices are used in a fluidized bed reactor loaded with the as-prepared CNS as the catalyst bed.

• Journal of the Korean Ceramic Society
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• v.34 no.5
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• pp.467-472
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• 1997

Porous silicon was prepared by an anodic etching. The pore size was about 10 nm at an etching time of 20 sec and a current density of 20 mA/$\textrm{cm}^2$. The porous layer was composed of an micro-porous layer (0.6 ${\mu}{\textrm}{m}$) and a macro-porous layer (10 ${\mu}{\textrm}{m}$). Room temperature PL with maximum peak 6700$\AA$ appeared. The peak disappeared by an oxidation reaction when the porous silicon was heated to 100~20$0^{\circ}C$ in atmosphere. In order to avoid the oxidation a heat treatment was done in H2 atmosphere. The micro-pore and Si column, which formed quantum well, were collapsed by the high temperature. The PL maximum peak of heated sample was gradually red-shifted and showed about 300$\AA$ red-shift at 50$0^{\circ}C$. The intensity of PL was maintained to high temperatures in lower pressures. The porous Si was carbonized in C2H2+H2 gas in order to increase thermal stability. The carbonization of the porous Si prevented red-shift of the maximum PL peak caused by sintering effect at high temperatures, and the carbonized porous Si showed Pl signal at higher temperatures by above 20$0^{\circ}C$ than the sample in H2 atmosphere.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.93-96
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• 2002

원자층증착법으로 제조한 청색 CaS:Pb 박막 형광체에 대한 열처리 및 전자빔 조사 효과찰 연구하였다. CaS:Pb 형광 박박의 열처리는 500 - $700^{\circ}C$ 온도범위에서 급속 열처리 공정으로 수행하였고, 1 kV, $20{\mu}A/cm^{2}$ 조건의 전자빔을 연속적으로 조사하여 열화를 가속시킨 후 처리 전, 후의 재료 및 cathololuminescence (CL) 특성을 비교 분석하였다. 원자층증착법으로 성장한 CaS:Pb 박막은 화학적 조성과 결정성이 우수하여 후속 열처리에 의해 발광특성이 크게 증가하는 경향을 보이지 않았으며, 전자빔에 의한 열화 정도는 판매되고 있는 형광체에 비하여 오히려 적었다. CL 강도가 초기값의 50%로 감소할 때까지 전자빔을 조사한 후에도 주목할만한 결정성 및 조성의 변화는 관찰되지 않았으나 전자빔 조사에 의해 표변에 두께 10 nm 내외의 탄소오염층이 형성됨을 알 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.11
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• pp.76-82
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• 1997

The characteristics of optical waeguides and IDT electrodes fabricated for acousto-optic tunable filters (AOTE) used for optical communications were analyzed. A $Ti:LiNbO_3$ in-diffusion method was employed for the formation of the optical waveguide with a dimension of width $8\mu\textrm{m}$, length $30000\mu\textrm{m}$, and thickness $1150{\AA}$. The diffusion was carried at $1050^{\circ}C$ for 8 houss to pattern the optical waveguide with Ti. The resulted waveguide exhibited a single mode at a 1550nm wavelength range and its propagation loss was less than 0.5dB/cm. The width of IDT, with 10 SAW periods, was $5000\mu\textrm{m}$, S11 reflection characteristics and impedances of th eelectrodes deposited with Au were analyzed using a network analyzer; $48.1\Omega$ at th ecenter frquency of 193MHz for Au deposition thickness of $1500{\AA}$ and $50.7\Omega$ at the center frequency of 192MHz for au deposition thickness of $1600{\AA}$.

• ETRI Journal
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• v.39 no.3
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• pp.326-335
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• 2017

In the uplink transmission of massive (or large-scale) multi-input multi-output (MIMO) systems, large dimensional signal detection and its hardware design are challenging issues owing to the high computational complexity. In this paper, we propose low-complexity hardware architectures of Richardson iterative method-based massive MIMO detectors. We present two types of massive MIMO detectors, directly mapped (type1) and reformulated (type2) Richardson iterative methods. In the proposed Richardson method (type2), the matrix-by-matrix multiplications are reformulated to matrix-vector multiplications, thus reducing the computational complexity from $O(U^2)$ to O(U). Both massive MIMO detectors are implemented using a 65 nm CMOS process and compared in terms of detection performance under different channel conditions (high-mobility and flat fading channels). The hardware implementation results confirm that the proposed type1 Richardson method-based detector demonstrates up to 50% power savings over the proposed type2 detector under a flat fading channel. The type2 detector indicates a 37% power savings compared to the type1 under a high-mobility channel.

• Journal of Electrochemical Science and Technology
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• v.7 no.1
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• pp.82-89
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• 2016

In this work, a ruthenium dioxide electrode has been prepared by thermal decomposition at 400 ℃ then used for the oxidation of commercial amoxicillin. The physical characterization showed that RuO₂ electrode presents a mud cracked structure. Its electrochemical characterization has revealed an increase of the voltammetric charge in acid electrolyte compared to neutral electrolyte indicating the importance of protons in its surface redox processes. The voltammetric study of the oxidation of amoxicillin has been investigated. It has been obtained that the oxidation of amoxicillin is controlled by both adsorption and diffusion processes. Moreover, the oxidation of amoxicillin occurs via direct and indirect processes in free or electrolyte containing chlorides. Through preparative electrolysis, enhancement of amoxicillin oxidation was observed in the presence of chloride where the amoxicillin degradation yield reached more than 50 % compared to less than 5% in the absence of chlorides. Spectrophotometric investigations have revealed the degradation of intermediates absorbing at 350 nm.

• Journal of Environmental Health Sciences
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• v.13 no.2
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• pp.75-81
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• 1987

Epidemiological study on the bovine mastitis was carried out on 1,493 raw milk samples from 7,406 dairy cows of dairyfarms in Chonnam province. And, it were classified by R. B. V. test during the period from July, 1984 to June, 1986. Of these positive samples, the mastitis causative agents were isolated, and examined for susceptibility to 14 antibiotics by disc method. The results are summarized as follows 1. Incidence rate of bovine mastitis from raw milk examined was observed in 1,393 dairy cows (18.8%) among 7,406 dairy cows of dairy farms. These outbreaks according to years were increased to 17.1% in 1984, 19.7% in 1985, and 20.5% in 1986. And, outbreaks of bovine mastitis according to seasons were high observed during the period from August to October. 2. Isolated rate of mastitis causative agents from raw milk was observed in the order of Staphylococcus sp. (50.2-51.7%), Streptococcus sp. (35.6-48.3%), Bacillus sp. (2.2-6.7%), Pseudomonas sp. (0.3-5.7%), and others (0.6%). 3. Generally, antibiotics susceptibility of isolated mastitis agents from raw milk was observed high susceptible in CP, CL, NB, PC, SM, NM, EM, GM etc.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.78.1-78.1
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• 2017

We present a noble method to determine BH mass of many AGNs directly through reverberation mapping using a small telescope with wide-field of view. In 2017 August we installed five medium-band filters to a 0.25m diameter $5deg^2$ FOV telescope at the McDonald observatory. The width of these filters (FWHM ~ 50nm) are matched to the broad line width of type-1 AGNs at various redshifts. From recently obtained data, about r ~ 19 magnitude AGNs can be detected in line component with 150s exposure. With this magnitude limit, about 20~30 AGNs can be studied in one field. We plan to carry out at one day cadence observation over 20~30 fields, enabling us to monitor up to ~1000 AGNs over a wide range of variability. This poster presents out plan and early results from test observation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.480-486
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• 2006

The radiation characteristics of a high-luminance light-emitting diode (LED) light source were studied to evaluate its potential as an energy-saving light source for fishing lamps. The angle of the LED light source with 50% illuminance was $8-15^{\circ}$, and it had strong directional characteristics. The wavelengths at which the radiance and irradiance were maxima were 709, 613, 473, 501, 525, and 465 nm for red, orange, blue, peacock blue, green, and white light, respectively. The underwater transmission characteristics of the LED light source were superior in the order blue, white, peacock blue, and green in optical water type I: blue, peacock blue, white, and green in optical water type II; and blue, peacock blue, green, and white in optical water type III. Setting the underwater transmission characteristics of the LED light source in optical water type I at 100%, the transmission of water types II and III decreased to 67 and 17%, respectively. Based on the underwater transmission characteristics calculated in optical water types I-III, the blue and peacock blue LED light sources can be used as an energy-saving light source for fishing lamps.

• BMB Reports
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• v.36 no.2
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• pp.149-153
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• 2003

The dibucaine number (DN) was determined for serum cholinesterase (EC 3.1.1.8, SChE) in plasma samples. The ones with a DN of 79-82 were used, because they had the "usual" SChE variant. The enzyme was assayed colorimetrically by the reaction of 5,5'-dithiobis-[2-nitrobenzoic acid] (DTNB) with the free sulfhydryl groups of thiocholine that were produced by the enzyme reaction with butrylthiocholine (BuTch) or acetylthiocholine (AcTch) substrates, and measured at 412 nm. Dibucaine, a quaternary ammonium compound, inhibited SChE to a minimum within 2 min in a reversible manner. The inhibition was very potent. It had an $IC_{50}$ of $5.3\;{\mu}M$ with BuTch or $3.8\;{\mu}M$ with AcTch. The inhibition was competitive with respect to BuTch with a $K_i$ of $1.3\;{\mu}M$ and a linear-mixed type (competitive/noncompetitive) with respect to AcTch with inhibition constants, $K_i$ and $K_I$ of 0.66 and $2.5\;{\mu}M$, respectively. Dibucaine possesses a butoxy side chain that is similar to the butryl group of BuTch and longer by an ethylene group from AcTch. This may account for the difference in inhibition behavior. It may also suggest the existence of an additional binding site, other than the anionic binding site, and of a hydrophobic nature.