• Progress in Superconductivity
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• v.3 no.1
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• pp.13-16
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• 2001

We have measured the reflectivity of superconducting infinite-layer compounds $Sr_{0.9}$ $Ln_{0.1}$ Cu $O_2$ (Ln=La, Gd, Sm) with $T_{c}$ : 39 K using a Fourier-transform infrared spectrometer. We have identified the optical phonon modes from their infrared reflectivity and conductivity spectra and have proposed possible displacement patterns. The La- and the Gd-doped compounds exhibited only four ($2A_{2u}$ $+2E_{u}$) out of the five ($2A_{2u}$ $3E_{u}$) infrared-active phonons predicted by a group theoretical analysis whereas the Sm-doped compound exhibited all five modes. For the La-doped sample, we investigated the temperature dependence of the optical response functions in a wide temperature range of 7 - 300 K. In FIR region, the reflectivity is apparently enhanced below ~120 $cm^{-1}$ as temperature decreases across $T_{c}$. The value of $2$\Delta$/k_{B}$ $T_{c}$ is about 4.5, which is consistent with maximum gap value of d-wave $high- T_{c}$ cuprates.> c/ cuprates.uprates.s.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.25-28
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• 2001

A theory of binary wavelets has been recently proposed by using two-band perfect reconstruction filter banks over binary field . Binary wavelet transform (BWT) of binary images can be used as an alternative to the real-valued wavelet transform of binary images in image processing applications such as compression, edge detection, and recognition. The BWT, however, requires large amount of computations since its operation is accomplished by matrix multiplication. In this paper, a fast BWT algorithm which utilizes filtering operation instead or matrix multiplication is presented . It is shown that the proposed algorithm can significantly reduce the computational complexity of the BWT. For the decomposition and reconstruction or an N ${\times}$ N image, the proposed algorithm requires only 2LN$^2$ multiplications and 2(L-1)N$^2$addtions when the filter length is L, while the BWT needs 2N$^3$multiplications and 2N(N-1)$^2$additions.

• Clean Technology
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• v.26 no.1
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• pp.7-12
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• 2020

Ti-SBA-15 catalysts doped with lanthanide ions (Ln/Ti-SBA-15) were successfully synthesized using conventional hydrothermal method. In addition, they were characterized by XRD, FT-IR, DRS, BET, and PL. The activity of these materials on the photocatalytic decomposition of methylene blue under ultraviolet light irradiation was also examined. Ti-SBA-15 catalysts doped with various lanthanide ions maintained their mesoporous structure. The pore size and pore volume of Ln/Ti-SBA-15 materials decreased but their surface area increased upon the doping of lanthanide ion. Ln/Ti-SBA-15 materials exhibited the type IV nitrogen isotherm with desorption hysteresis loop type H2, which was characteristic of mesoporous materials. The size of hysteresis increased in the doping of lanthanide ions on Ti-SBA-15 material. There was no absorption in the visible region (> 400 nm) regardless of the doping of lanthanide ions to TiO₂ particles, while the broad bands at 220 nm appeared at the Ln/Ti-SBA-15 samples, indicating the framework incorporation of titanium into SBA-15. 1 mol% Pr/ Ti-SBA-15 catalysts showed the highest photocatalytic activity on the decomposition of methylene blue but the Ti-SBA-15 catalysts doped with Eu, Er, and Nd ions showed lower activity compared to pure Ti-SBA-15 catalyst. The PL peaks appeared at about 410 nm at all catalysts while the excitonic PL signal was proportional to the photocatalytic activity for the decomposition of methylene blue.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.437-440
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• 1992

We design a multi-element photo-detector to measure the size of particles using the diffracted light energy distribution. The light energy that is scattered by particles in the collimated laser beam is collected by the Fourier transform lens and directed to the multi-semicircular concentric annular detecters. The scattered profile measured by the photodetector is sampled by a 32 channel analog-to-digital converter. A nonnegative least squares analysis translates the light energy distribution into the corresponding unique particle size distribution.

• Journal of the Korea Convergence Society
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• v.11 no.12
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• pp.23-30
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• 2020

In this study, the relationship between natural gas (NG) data and gas-related environmental elements was performed using machine learning algorithms to predict the level of gas leakage risk without directly measuring gas leakage data. The study was based on open data provided by the server using the IoT-based remote control Picarro gas sensor specification. The naturel gas leaks into the air, it is a big problem for air pollution, environment and the health. The proposed method is multivariate outlier removing method based Random Forest (RF) classification for predicting risk of NG leak. After, unsupervised k-means clustering, the experimental dataset has done imbalanced data. Therefore, we focusing our proposed models can predict medium and high risk so best. In this case, we compared the receiver operating characteristic (ROC) curve, accuracy, area under the ROC curve (AUC), and mean standard error (MSE) for each classification model. As a result of our experiments, the evaluation measurements include accuracy, area under the ROC curve (AUC), and MSE; 99.71%, 99.57%, and 0.0016 for MOL_RF respectively.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.3
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• pp.139-145
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• 2015

Effects of austenitizing, cryogenic treatment and tempering conditions on the phase change, microstructure and Vickers hardness value have been studied in STD11 steel for tool and die. The volume fraction of retained austenite increased with a rise in austenitizing temperature, while the volume fraction of eutectoid $M_7C_3$ carbides decreased. The retained austenite could be reduced by cryogenic treatment i.e., maintaining at $LN_2$ temperature ($-196^{\circ}C$) for 12hrs but a little amount of retained austenite did not transform to martensite further although holding time increased to 24 hrs or more. The microstructure of the quenched and then cryogenictreated specimen showed nano-sized and needle-shaped carbides in matrix due to the decomposition of martensite by tempering, but that of the one without cryogenic treatment still revealed retained austenite by tempering even at $500^{\circ}C$.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.923-927
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• 2005

ln order to develop yeast cells that produce a bacteriocin on their cell surfaces, the 114 bp Leucocin A gene with stop codon was ligated into pYDl, an yeast vector. The recombinant DNA, pYDl-LeucoA was used to transform yeast (Saccharomyces cerevisiae) cells. Yeast cells harboring pYDl-LeucoA showed antibacterial activity against Bacillus subtilis. To confirm these bacteriocidal yeast cells possess the Leucocin A gone, PCR was performed with plasmid prepared from transformed yeast cells as a template and two Leucocin A-specific primers. In this study, bacteriocidal yeast cells that can be used as an antibiotic or a food preservative were developed.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.7
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• pp.55-66
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• 2021

The purpose of this study is to analyze the relationship and effects of variables both directly and indirectly (e.g., investment (INV), government expenditure (GE), unemployment rate (UR), economic growth (EG), and income inequality). The analytical phases consist, first, to transform the data using the Log Natural (Ln) method. Second, to check normality and multicollinearity of data. Third, to test direct effects of variables (government expenditure and investment effect on the unemployment rate and economic growth; investment on government expenditure; economic growth on unemployment rate; economic growth and unemployment rate on income inequality). Fourth, to test indirect effects using Sobel test, which involves UR and EG as intervening variable. Fifth, to test hypotheses with p-value < 0.05. The results of the study reveal that, of the 12 relationships, statistics show that 11 variations of the association have significant positive and negative effects. Theoretically, the different characters and goals of GE and INV in each country will have a different impact on EG and UR goals. The study provides an input, especially for the government. To create optimal EG through GE and INV, it is necessary to allocate budgets to industrial sectors that can absorb a massive labor force and to new economic growth sectors.