• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.458-464
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• 2006

The Pd-Ni-Ag alloy composite membrane using modified porous stainless steel (PSS) as a substrate was prepared by a electroless plating technique. In this work, we have introduced the intermediate layer between Pd-based alloy and a metal substrate. As an intermediate layer, the mixtures of nickel powder and inorganic sol such as $SiO_{2}$ sol, $Al_{2}O_{3}$ sol, and $TiO_{2}$ sol were used. The intermediate layers were coated onto a PSS substrate according to various membrane preparation conditions and then $N_{2}$ fluxes through the membranes with different intermediate layers were measured. The surface morphology of the intermediate layer in the mixture of nickel powder and inorganic sol was analyzed using scanning electron microscope (SEM). Finally, the Pd-Ni-Ag alloy composite membrane using the support coated with the mixture of nickel powder and silica as an intermediate layer was fabricated and then the gas permeances for $H_{2}$ and $N_{2}$ through the Pd-based membrane were investigated. The selectivity of $H_2/N_2$ was infinite and the $H_{2}$ flux was $1.39{\times}10^{-2}mol/m^2{\cdot}s$ at the temperature of $500^{\circ}C$ and trans-membrane pressure difference of 1 bar.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.285-292
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• 1999

An analytical method applicable to quality control and its optimum conditions were studied for rapid and efficient analysis of sorbic and benzoic acids used as preservatives in the commercial soybean paste. In gas chromatographic analysis of sorbic and benzoic acids, the application of HP-FFAP (acid modified polyethylene) wide bore column improved the separation ability significantly. By setting the oven temperature of GC to $200^{\circ}C$, the total elapsed time for quantitative analysis was also reduced to the level required in using packed column. By extracting sorbic and benzoic acids from soybean paste with an automatic steam distillation device, the elapsed time for analysis was reduced by 80% more compared to using conventional steam distillation method. The recoveries of sorbic and benzoic acids by the automatic steam distillation were 98.1% and 99.9%, respectively. The sorbic acid was found in 3 samples of 14 commercial soybean pastes, of which contents were $466{\sim}530ppm$, while $0.3{\sim}4.4ppm$ of benzoic acid was found in all the samples.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.1-4
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• 2006

Method of analyzing sodium alginate in foods was developed using high performance liquid chromatography (HPLC). HPLC conditions for sodium alginate were: column, MCI GEL $(8\;mm\;i.d{\times}300\;mm)$; mobile phase, deionized water; detector, refractive index detection (sensitivity = 16). Separation of sodium alginate was achieved within 15 min. Sodium alginate showed good linear relationship at 0.1-2.0% range. Correlation coefficient of calibration curve for sodium alginate exceeded 0.999, and detection limit was 0.005%. Recovery rate of sodium alginate in wheat flour dough was 106.67%. This method was successfully applied to analyses of cereals, saccharides, and ice cream, etc. Sodium alginate was detected in chocolate, noodles, and kelp at 0-44.8% range.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.3
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• pp.1-11
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• 2011

Located in Namwon-si, Jeonlla Bukdo, Gwanghallu Garden is created around Gwanghallu, which was a government office in the period of Joseon Dynasty and shows its looks as a government office building of the times. However, Gwanghallu Garden is recognized rather as a background site of Chunhyangjeon, representing a local culture, than the features and picture as a government office garden in the period of Joseon Dynasty because Gwanghallu appeared as the background of Chunhyangjeon in its Chinese character script and, after 1930s, Chunhyang Sadang was built up and Chunhyang Festival held, and it's recognized rather as a site for arousing national consciousness and cherishing Chunhyang for its integrity in the Japanese ruling era of Korea than as a government office building in the period of Joseon Dynasty. With it being more recognized as the background of Chunhyangjeon than an ancient government office building, Gwanghallu has been managed as a private house garden or event place of folk festival as the background of Chunhyangjeon than preserved and managed as ancient government office building, and now the looks and features as a garden of government office are hardly seen because of indiscriminate trees and making of structure and spaces. Therefore, to preserve and maintain Gwanghallu Garden as the garden of government office in the period of Joseon Dynasty, it's required to survey the trees, structure and spaces created in Gwanghallu Garden and compare the true condition with its original looks by studying its literature and it's suggested that the garden area created around Gwanghallu should be repaired and managed by separation from as the background of Chunhyangjeon. Such means of management may keep the looks of Gwanghallu as the ancient office garden while Chunhyangjeon can also settle down as a local culture in the background.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.135-141
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• 2020

The silica aerogels with benzene-bridged were designed to have uniform network structure, ordered pore structure, improved mechanical properties and excellent textural properties. Adding organic to enhance the mechanical properties of silica aerogels is a common method, but textural properties of aerogels with organic are reduced due to the organic-inorganic phase separation. In this paper, we use a simple and low-cost method to increase mechanical properties while maintaining textural properties of SiO2 aerogels. Two types of benzene-bridged precursors were prepared to study the effect of the number of hydroxyl band on the textural and mechanical properties. The porous silica aerogel was prepared by a simple, cost effective and pollution-free sol-gel method. This method does not require additional silylating reagents. The benzene-bridged silica aerogel samples prepared had excellent textural properties, high specific surface area (1,326 ㎡/g), porous structure and hydrophobicity (>140°). The mechanical strength of 2T4 is more than 5 times that of pure silica aerogel.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.174-175
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• 2012

(In, Ga) N-based III-nitride semiconductor materials have been viewed as the most promising materials for the applications of blue and green light emitting devices such as light-emitting diodes (LEDs) and laser diodes. Although the InGaN alloy can have wide range of visible wavelength by changing the In composition, it is very hard to grow high quality epilayers of In-rich InGaN because of the thermal instability as well as the large lattice and thermal mismatches. In order to avoid phase separation of InGaN, various kinds of structures of InGaN have been studied. If high-quality In-rich InGaN/GaN multiple quantum well (MQW) structures are available, it is expected to achieve highly efficient phosphor-free white LEDs. In this study, we proposed a novel InGaN double hetero-structure grown on GaN nano-pyramids to generate broad-band red-color emission with high quantum efficiency. In this work, we systematically studied the optical properties of the InGaN pyramid structures. The nano-sized hexagonal pyramid structures were grown on the n-type GaN template by metalorganic chemical vapor deposition. SiNx mask was formed on the n-type GaN template with uniformly patterned circle pattern by laser holography. GaN pyramid structures were selectively grown on the opening area of mask by lateral over-growth followed by growth of InGaN/GaN double hetero-structure. The bird's eye-view scanning electron microscope (SEM) image shows that uniform hexagonal pyramid structures are well arranged. We showed that the pyramid structures have high crystal quality and the thickness of InGaN is varied along the height of pyramids via transmission electron microscope. Because the InGaN/GaN double hetero-structure was grown on the nano-pyramid GaN and on the planar GaN, simultaneously, we investigated the comparative study of the optical properties. Photoluminescence (PL) spectra of nano-pyramid sample and planar sample measured at 10 K. Although the growth condition were exactly the same for two samples, the nano-pyramid sample have much lower energy emission centered at 615 nm, compared to 438 nm for planar sample. Moreover, nano-pyramid sample shows broad-band spectrum, which is originate from structural properties of nano-pyramid structure. To study thermal activation energy and potential fluctuation, we measured PL with changing temperature from 10 K to 300 K. We also measured PL with changing the excitation power from 48 ${\mu}W$ to 48 mW. We can discriminate the origin of the broad-band spectra from the defect-related yellow luminescence of GaN by carrying out PL excitation experiments. The nano-pyramid structure provided highly efficient broad-band red-color emission for the future applications of phosphor-free white LEDs.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.469-477
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• 2008

Purpose: The goal of this paper is to present the design and performance of a position encoding circuit for $16{\times}16$ array of position sensitive multi-anode photomultiplier tube for small animal PET scanners. This circuit which reduces the number of readout channels from 256 to 4 channels is based on a charge division method utilizing a resistor array. Materials and Methods: The position encoding circuit was simulated with PSpice before fabrication. The position encoding circuit reads out the signals from H9500 flat panel PMTs (Hamamatsu Photonics K.K., Japan) on which $1.5{\times}1.5{\times}7.0\;mm^3$ $L_{0.9}GSO$ ($Lu_{1.8}Gd_{0.2}SiO_{5}:Ce$) crystals were mounted. For coincidence detection, two different PET modules were used. One PET module consisted of a $29{\times}29\;L_{0.9}GSO$ crystal layer, and the other PET module two $28{\times}28$ and $29{\times}29\;L_{0.9}GSO$ crystal layers which have relative offsets by half a crystal pitch in x- and y-directions. The crystal mapping algorithm was also developed to identify crystals. Results: Each crystal was clearly visible in flood images. The crystal identification capability was enhanced further by changing the values of resistors near the edge of the resistor array. Energy resolutions of individual crystal were about 11.6%(SD 1.6). The flood images were segmented well with the proposed crystal mapping algorithm. Conclusion: The position encoding circuit resulted in a clear separation of crystals and sufficient energy resolutions with H9500 flat-panel PMT and $L_{0.9}GSO$ crystals. This circuit is good enough for use in small animal PET scanners.

• Journal of Society of Preventive Korean Medicine
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• v.7 no.1
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• pp.17-28
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• 2003

We met results like the followings through the literatures and questionnaires about the tasks and solutions about the insurance fee of packed medical herbs. 1) It's turned out that 74.8% of herb doctors agrees to the insurance fee of packed medical herbs. However, in comparison with the same survey of the herb doctor association the percentage of general approval went somewhat lower, and especially the percentage of 'positive approval' became notably lower$(43.7%{\rightarrow}26.5%)$ and the percentage of 'active objection' raised about 2 times$(6.8%{\rightarrow}12.9%)$. Inquiring into the approval reasons on the insurance fee application of packed medical herbs some heads such as 'development toward treatment medical science' and 'decrease of publics burden' were higher than the one of 'management income and expenditure.' 2) As a result of the research, 36.0% of the patients and 42.8% of the residents recognized that the pay range of Chinese herb health insurance is narrow. They recognized that less people have the experiences of Chinese medical hospital use and internal application of the packed medical herbs as they are older, men rather than women. 85.4% of the patients and 74.9% of the residents agreed on the insurance pay of packed medical herbs. It's shown that they agree on the Chinese medical hospital use more as the economic standard is lower, on the insurance pay as they have ever taken the packed medical herbs. In the aspect of increase of insurance fee, 66.7% of the patients and 44.3% of the residents agreed on the insurance pay of packed medical herbs, and 18.1% and 36.1% disagreed on the insurance pay of packed medical herbs. The main objective reason why they disagree on the insurance pay of packed medical herbs was 'because the insurance fee goes up higher,' which answered 95.2% of the patients and 78.8% of the residents. 7.22% of the patients and 1.80% of the residents answered that they can pay more insurance fee in case of the insurance pay of packed medical herbs. However, in the priority order of the insurance pay, it hold the 5th position between 2 target research groups which was less than medical examination, charges for hospital accommodation and taking MRI. 3) According to the result of analysis about the cost of packed medical herbs, current practice price is 115,000 won and the average prime cost of a packed medical herb is 73,000 to 106,000 won. It's examined that the herb doctors regard that 95,000 won will be reasonable when the packed medical herb is payed in insurance. However, it was found out that the public generally thinks that the price would be appropriate on the level of 30,000 to 40,000 won and the percentage of the answers of 20,000 won to 30,000 was fairly high. 4) the central system of a prescription should be change into the central system of demonstration and the sick and wounded. 5) To solve this problem, the government should regulate it to pass by the circulation gradation of [importer, $peasantry{\rightarrow}manufacturer{\rightarrow}wholesaler{\rightarrow}distributor$(Chinese medical hospital, pharmacy dispensary of Chinese medicine)]And it should intervene into the quality and the circulation steps of Chinese medicine through 'the office or organization which is in charge of certification of Chinese medicine' and 'the office or organization which is in charge of the circulation of Chinese medicine.' And some actions such as simple severance, lavation, drying should be included into the conception of manufacture and the boundary between food and medical supplies should be made at a manufactory. And the regulation of standardized goods at one's own house should be improved so that, the peasantry can sell the materials of Chinese medicine only to the manufacturer. 6) In company with the insurance pay of packed medical herbs, the study about the separation of dispensary from medical practice in the Chinese medicine should be accomplished.