• The Korean Journal of Food And Nutrition
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• v.7 no.1
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• pp.1-7
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• 1994

To investigate the characteristics of active sites of the D-xylanase and $\beta$-xylosidase purified from Penicillium verruculosum, effects of various chemicals on the enzyme activity were analyzed. The D-xylanase was activated by Cua), however it was inhibited by metal ions, Hg2+ and Mna+, by chemicals, N-bromosuccinimide, iodine, diethylpyrocarbonate, and 2,3-butanedione. These results suggested that the D-xylanase from Penicillium verruculosum contained tyrosine, histidine, arginine and tryptophan at the active center. The $\beta$-xylosidase was inhibited by Hg2+, N-bromosuccinimide and sodium dodecyl sulfate, however it was not effected by Mn2+ and Cu2). It was suggested that the enzyme contained tryptophan at the active center.

• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.70-73
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• 2017

We investigated n-i-p type single junction hydrogenated amorphous silicon oxide solar cells. These cells were without front surface texture or back reflector. Maximum power point efficiency of these cells showed that an optimized device structure is needed to get the best device output. This depends on the thickness and defect density ($N_d$) of the active layer. A typical 10% photovoltaic device conversion efficiency was obtained with a $N_d=8.86{\times}10^{15}cm^{-3}$ defect density and 630 nm active layer thickness. Our investigation suggests a correlation between defect density and active layer thickness to device efficiency. We found that amorphous silicon solar cell efficiency can be improved to well above 10%.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.939-942
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• 2016

One of the most important characteristic curves of a solar cell is its current density-voltage (J-V) curve under AM1.5G insolation. Solar cell can be considered as a semiconductor diode, so a diode equivalent model was used to estimate its parameters from the J-V curve by numerical simulation. Active layer plays an important role in operation of a solar cell. We investigated the effect thicknesses and defect densities (N_d) of the active layer on the J-V curve. When the active layer thickness was varied (for N_d = 8×10¹⁷ cm^-3) from 800 nm to 100 nm, the reverse saturation current density (J_o) changed from 3.56×10^-5 A/cm² to 9.62×10^-11 A/cm² and its ideality factor (n) changed from 5.28 to 2.02. For a reduced defect density (N_d = 4×10¹⁵ cm^-3), the n remained within 1.45≤n≤1.92 for the same thickness range. A small increase in shunt resistance and almost no change in series resistance were observed in these cells. The low reverse saturation current density (J_o = 9.62×10^-11 A/cm²) and diode ideality factor (n = 2.02 or 1.45) were observed for amorphous silicon based solar cell with 100 nm thick active layer.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.6
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• pp.46-53
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• 1998

A new method to form the double structured active layers of a-Si/a-SiN$_{x}$ of polycrystalline thin film transistor is proposed and poly-Si TFTs employed double structure active film are fabricated. Nitrogen ions were added to bottom amorphous silicon active film(a-SiN$_{x}$ ) and pure a-Si film deposition on a-SiN$_{x}$ was followed. The XeCl excimer laser was irradiated to crystallize double structure active film. The grain growth of upper a-Si film was also promoted in the double structured active layers of a-Si/a-SiN$_{x}$ due to the mitigation of solidification process of lower a-SiN$_{x}$ layer. Our experimental results show that the ratio of NH$_3$/SiH$_4$ is required to maintain below 0.11 for the reduction of contact resistance of n$^{+}$ poly-SiN$_{x}$ layer.r.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.344-348
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• 2015

The image data of the web camera is used to identify the construction status of the site in a remote office and it can be used for safety management. This study develops a construction schedule simulation system based on the active nD object linked with real image data of web camera from the construction site. The progress control method by 4D object uses a method that the progress of each activity is represented with different colors by progress status. Since this method is still based on a virtual reality object, it is less realistic description for practical engineers. Therefore, in order to take advantage of BIM more realistic, the real image of actual construction status and 4D object of planned schedule in a data date should be compared in a screen simultaneously. Those methodologies and developed system are verified in a case project where a web camera is installed for the verification of the system.

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.172-177
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• 1989

Stereoselective solvolyses of optically active activated esters in the aggregate system of optically active polymeric surfactants containing imidazole and benzene moieties were performed. The catalyst polymers employed were copolymers of N-methacryloyl-L-histidine methyl ester (MHis) with N,N-dimethyl-N-hexadecyl-N-[10-(p-methacryloylo xyphenoxycarbonyl)-decyl]ammonium bromide(DEMAB). In the solvolyses of N-carbobenzoxy-D- and L-phenylalanine p-nitrophenyl esters (D-NBP and L-NBP) by polymeric catalysts, copoly(MHis-DEMAB) exhibited not only increased catalytic activity but also enhanced enantioselectivity as the mole ${\%}$ of surfactant monomers in the copolymers increased. The polymeric catalysts showed noticeable enantioselective solvolyses toward D- and L-NBP of the substrates employed. As the reaction temperature was lowered for the solvolyses of D- and L-NBP with the catalyst polymer containing 3.5 mole ${\%}$ of MHis, the increased reaction rate and enhanced enantioselectivity were observed. The coaggregative systems of the polymer and monomeric surfactants were also investigated. In the case of coaggregate system consisted of 70 mole ${\%}$ of cetyldimethylethylammonium bromide with polymeric catalyst showed maximum enantioselective catalysis, viz., $k_{cat}(L)/k_{cat}(D)$ = 2.85. The catalyst polymers in the sonicated solvolytic solutions were confirmed to form large aggregate structure by electron microscopic observation.

• Macromolecular Research
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• v.12 no.3
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• pp.258-262
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• 2004

We have developed facile and rapid polycondensation reactions of N-trimellitylimido-L-leucine diacid chloride 1 with eight different derivatives of hydantoin compounds 2a-h, in the presence of a small amount of a polar organic medium, such as Ο-cresol, by using a domestic microwave oven. The polycondensation reactions proceeded rapidly-they were complete within 7-9 min-to produce a series of novel optically active poly(amide-imide)s (3a-h) in high yield with inherent viscosities of 0.33-0.51 dL/g. We characterized the resulting poly(amide-imide)s by elemental analysis, thermal gravimetric analysis (DSC, TGA, and DTG), and FTIR spectroscopy, and by measuring their viscosities, specific rotations, and solubilities. All of the polymers were soluble at room temperature in polar solvents such as N ,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetrahydrofuran, and N-methyl-2-pyrrolidone.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.857-867
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• 2018

Active array radar is evolving into digital active array radar. Digital active array radar has many advantages for making several simultaneous radar beams from the digital receive data of each element. A digital-type transceiver(TR) module is suitable for this goal in radar. In this work, the design results of an L-band digital TR module are presented to verify the possibility of fabrication for a digital active array antenna. This L-band digital TR module consists of a gallium-nitride-type HPA to achieve a more than 350-W peak output power and one-chip transceivers that include a digital waveform generator and analog digital converter. The receiving gain was 47 dB, the noise figure was less than 2 dB, and the final output type of the four channel receiving paths was one optic signal.

• YAKHAK HOEJI
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• v.29 no.6
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• pp.375-379
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• 1985

The gas chromatographic behavior of optically active N-(N-benzoyl-L-valyl)-anilide used as stationary phase is described. N-(N-benzoyl-L-valyl)-anilide has been synthesized with good yield under mild condition via Schotten-Bauman process and coated on the Chromosorb W AW (80-100mesh) for the purpose of enantiomer separation. The behavior of this compound as optically active stationary phase for the separation of the enantiomers of N-TFA-D, L-amino acid isopropyl esters has been examined with respect to the correlation between the separation factors and column temperatures. All amino acid enantiomers examined were eluted within one hour and the elution pattern showed retention times increasing in the order of alanine, valine, leucine, threonine, proline and methionine.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.445-453
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• 2000

In this paper, the method of designing an active inductor for MMIC is proposed. The proposed tunable active inductor is composed of a cascade FET with feedback capacitors and resistors. Because of a very low series resistance in the proposed inductor, a very high Q factor can be obtained. Also it has an excellent characteristics suitable for high frequency band. The inductance value can be changed by controlling feedback capacitors, resistors and a bias voltage respectively. When the feedback resistor and parallel resistor within circuits are varied, the inductance value is changed from 0.2 nH to 1.7 nH in the range 1 to 15 GHz. Also we designed bandpass filter using the proposed active inductor and it shows the insertion loss of 0.4 dB and return loss, 20 dB.