• Korean Journal of Optics and Photonics
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• v.24 no.5
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• pp.256-261
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• 2013

Power conversion efficiency of the red and green phosphors was measured and analyzed. Two different samples of phosphors of thickness 50 ${\mu}m$ were prepared: one was the phosphor layer coated on the transparent substrate and the other was prepared on the reflective substrate. The 445 nm blue laser diode beam was used as the exciting beam. The conversion efficiencies of the red and green phosphor layers were 41.4% and 46%, respectively. The quantum efficiencies of the red and green phosphors were 60.4% and 53.5%, respectively.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.1
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• pp.19-22
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• 2003

The co-evaporated cathodes composed of A1 and CsF is adopted to enhance the electrical and the optical properties of organic light emitting diodes (OLEDs). The hole transport layer (HTL), made of 50nm thick N,N-dipheny1-N,N-bis(3-methylphenyl)-1,1-bipheny14,4-diamine (TPD), and the electron transport layer (ETL), made of 50nm thick tris(8-hydroxy-quinoline) aluminum (A1q$_3$), were deposited under the base pressure of 1.6$\times$10$^{-6}$ Torr. In depositing A1-CsF, the mass ratio of CsF is varied between 1 and 10wt%. OLEDs with co-evaporated cathodes have luminance of about 35,000cd/$m^2$, and external quantum efficiency of about 1.38%. Cs tends to diffuse into the organic layer and then re-forms Cs$^{+}$cation and free electron with the Cs-doped surface region.n.

• Transactions on Electrical and Electronic Materials
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• v.12 no.1
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• pp.20-23
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• 2011

Amorphous Ti-(50-x)Ni-xCu (at%) (x = 20, 25, 27, 30) alloy ribbons were prepared by melt spinning. Subsequently, the crystallization behavior of the alloy ribbons was investigated by X-ray diffraction and differential scanning calorimetry. ${\Delta}T$ (the temperature gap between $T_g$ and $T_x$) increased from 33 K to 47 K and the wavenumber ($Q_p$) decreased from 29.44 $nm^{-1}$ to 29.29 $nm^{-1}$ with increasing Cu content from 20 at% to 30 at%. The activation energy for crystallization decreased from 188.5 kJ/mol to 170.6 kJ/mol with increasing Cu content from 20 at% to 25 at%; afterwards, the activation energy remained near constant. Crystallization occurred in two-stage: amorphous-B2-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content less than 25 at%, while it occurred in three-stage; amorphous-B2-TiCu-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content more than 27 at%.

• Journal of the Mineralogical Society of Korea
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• v.20 no.4
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• pp.255-260
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• 2007

The loess on the Chinese loess plateau is not only the accumulation of Asian dust but also the source materials of Hwangsa. The eolian carbonates of the loess were dissolved and reprecipitated to form secondary pedogenic carbonates by the post-depositional weathering during the interglacial time. Mineralogical analysis shows that the secondary calcites are composed mostly of a nanosized fibrous calcite with rather constant width ($30{\sim}50nm$) and highly variable length. The nano calcite is the major authigenic mineral, which occurs as the fine-grained matrix of the loess and paleosol. The nano calcite was recently reported in the Hwangsa, where it was originated from the source regions of Chinese loess plateau.

• Korean Journal of Optics and Photonics
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• v.22 no.3
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• pp.117-121
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• 2011

We propose a saturable absorber reflector based on guided-mode resonance. A carbon nanotube is used as a saturable absorber. By tuning the fill factor, modulation depth can be increased without a change of height of the CNT. We investigate the reflector properties such as modulation depth, bandwidth and peak reflectance as a function of the height of the CNT and the fill factor. The advantage of the proposed reflector is that it can reduce saturation energy by 50 times compared with CNT thin film of 100~200nm.

• YAKHAK HOEJI
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• v.41 no.4
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• pp.407-413
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• 1997

Magnolol and honokiol, the main components of Magnoliae Cortex, were isolated and used as the standard substances for the analysis. In order to determine the contents of magnolol and honokiol in Magnoliae Cortex originated from Korea, China and Japan, both HPLC and HPTLC methods are applied and compared with each other. The components were separated on C8 column with acetonitrile-water-acetic acid (50:50:1) in HPLC and detected at UV 294nm. The components separated on HPTLC precoated silica gel plate with chloroform-methanol (9:1) were detected directly on the plate at 254nm. The contents of magnolol and honokiol in Magnoliae Cortex were in the wide range of 0.01~2.8% and 0.005~0.8%, respectively, according to their purchase places. It is also applicable to the quality control of various preparation from Magnoliae Cortex.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.575-578
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• 2011

We fabricated a novel simple and rapid method of three dimensional nanoporous gold thin film (NPGF) onto a Au substrate using electrochemical deposition method. The NPGF-modified electrode analysis by scanning electron microscope and reveals the formation of nanopores, approximately 30~50 nm in diameter. differential pulse voltammetry was measured for the determination of ${\gamma}$-aminobutiric acid in the concentration range of ($10{\sim}100{\mu}M$ using a NPGF. The high sensitivity feature of NPGF is expected to be applied for real sample biosensor applications.

• Journal of IKEEE
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• v.24 no.4
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• pp.1172-1175
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• 2020

Automotive ECU integrates CPU core, IVN controller, memory interface, sensor interface, I/O interface, and so on. Current automotive ECUs are often developed with proprietary processor architectures. However, demends for standard processors such as ARM and RISC-V increase rapidly for saftware compatibility in autonomous vehicles and connected cars. In this paper, an automotive ECU is designed for parking assist system based on RISC-V with open instruction set architecture. It includes 32b RISC-V CPU core, IVN controllers such as CAN and LIN, memory interfaces such as ROM and SRAM, and I/O interfaces such as SPI, UART, and I2C. Fabricated in 65nm CMOS technology, its operating frequency, area, and gate count are 50MHz, 0.37㎟, and 55,310 gates, respectively.

• Natural Product Sciences
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• v.27 no.4
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• pp.264-273
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• 2021

Simultaneous quantification of multiple marker compounds in herbal medicine by high performance liquid chromatography (HPLC) analysis is still a challenge due to the complexity in various parameters to be considered and co-existing multi-components. As a case study, a reliable HPLC method for simultaneous quantification of paeoniflorin from Paeoniae Radix and decursin from Angelicae Gigantis Radix in various commercial herbal medicine was developed based on analytical quality by design (AQbD) strategy. As a first step, risk assessment was performed to select the critical method parameters (CMPs) which were decided as organic mobile phase ratio and column oven temperature. In order to evaluate the effect of the CMPs on critical method attributes (CMAs) of peak resolution and tailing, central composite design (CCD) was employed. The final chromatographic conditions were optimized as follows: column- C₁₈, 4.6 × 250 mm, 5 ㎛ particle size; mobile phase- A: acetonitrile, B: 0.1% acetic acid water; detection wavelength- 235 nm for paeoniflorin, 325 nm for decursin; column oven temperature- 25℃; flow rate- 1.0 mL/min; gradient mobile phase system as Time (min) : % A, 0:14, 25:14, 30:50, 60:50, 61:100, 65:100, 66:14, 75:14. The method was successfully validated according to the International Conference on Harmonization (ICH) guidelines and piloted for ten commercial herbal medicines.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.107-112
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• 2022

In this study, a silver paste capable of UV curing without using any solvent was developed. The viscosity and viscoelasticity of the silver paste developed as a solvent-free type were measured. And after printing the pattern by screen printing, an electrode coating film was formed by UV curing. Conductivity, pencil hardness, and adhesive force of the formed electrode coating film were evaluated. Finally, the curing characteristics of the electrode coating film were evaluated by TGA and FT-IR. Summarizing these results, in terms of conductivity, adhesion, and curing characteristics, it was found that Paste (4), that is, silver paste obtained by mixing 1.2 ㎛ spherical silver powder and 50 nm silver powder at 72:8% had the best physical properties.