• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.6 no.2
• /
• pp.105-109
• /
• 2005

We heat treated pure sapphire samples at $1800^{\circ}C{\sim}100$ hours in BeO-${Al_2}{O_3}$ powder by varying BeO contents of $5{\sim}50\;wt%$ in order to quantify the BeO diffusion enhancement for corundum gem stones. We investigated the heat treated samples with visual evaluation, color coordination analysis, and surface roughness measurement. We confirmed that $Be^{2+}$ ions did not lead to orange color but to dark gray. The lightness in CIE Lab index decreased while surface roughness increased rapidly as BeO contents increased. We propose that BeO yellow color enhancement may be feasible only for $Fe^{3+}$ rich blue sapphires and sub-5% BeO content be appropriate to shorten post re- cutting process.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.9
• /
• pp.420-426
• /
• 2018

Acoustic Quanta, which British Physicist Dennis Gabor created, is the theoretical background for granular synthesis and has influenced many computer music artists and sound designers. Acoustic Quanta is a very short sound burst, lasting only 1 to 100 ms. Granular synthesis is a sound synthesis technique which slices original sound into sound grains and re-combines them into a new acoustic event. Concept of sound grain is borrowed from the acoustic quanta. Granular Synthesis can make very unique sound, so that it can be useful in many ways, especially in sound design. This paper presents concept of acoustic quanta and granular synthesis. It then discusses making a synthesizer as an implementation of synchronous granular synthesis and its applications on sound design. As a result, the duration of acoustic quanta should range between 0.239 and 33.367 ms, in consideration of audible frequencies, which is different from the original concept of the acoustic quanta.

• Archives of Reconstructive Microsurgery
• /
• v.13 no.2
• /
• pp.101-106
• /
• 2004

Purpose : This study evaluated the effect of VEGF in the arterial anastomosis by using light and electron microscopy. Marerials and method : Rats underwent femoral arterial end-to-end anastomosis after transection and topical VEGF treatment. The proximal and distal segments of the femoral arteries was drenched with 1 drop of VEGF $(100ng/100{\mu}l/bottle)$. and when half of the repair was finished, the other 1 drop was drenched and then the repair was continued to complete the anastomosis. Gross and histologic characteristics of arterial wall were assessed after 3 days, 1, 3 and 5 weeks. In the control group, normal saline solution instead of VEGF was dropped with the same method in the anastomosis. Results : The histologic findings of the arterial wall were the vascular remodeling with the infiltration of inflammatory cells at early stages and the tissue fibrosis at lately stages in the anastomotic sites of the control and the VEGF-treated groups. The scanning electron microscopic results were; (1) the anastomotic sites were covered by many irregular cells with long cytoplasmic processes at the early stages. (2) After 1 week, endothelial cells started to cover the anastomotic sites. (3) After 3 weeks, the anastomotic sites were partially covered by endothelial cells in the control group. (4) After 5 weeks, the anastomotic sites were completely covered by endothelial cells in the control and VEGF-treated groups. (5) In the VEGF-treated group, the anastomotic site was completely covered by endothelial cells which directed parallel to longitudinal axis of arteries after 3 weeks. Conclusion : Topical VEGF maintained luminal integrity by decreasing fibrosis and increasing re-endothelialization. These findings suggest that topical VEGF may be a promising new strategy to enhance healing and improve the outcome of vascular anastomosis.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.24 no.3
• /
• pp.416-425
• /
• 2010

The object of this study was to observe the protective effects of Yijin-tang-gamibang (YJGMB), Yijin-tang has been traditionally used in the Korean Medicine for treating various digestive diseases. The study showed that it is effective on reflux esophagitis induced by pylorus and forestomach ligation in rats. Three different dosages of YJGMB extracts, 200, 100 and 50 mg/kg, were orally pretreated, once a day for 28 days before pylorus and forestomach ligation. Seven groups, each of 8 rats per group were used in the present study. The results were compared with omeprazole, antioxidant and proton pump inhibitor, 30 and 10 mg/kg treated group. YJGMB 200 mg/kg were showed similar protective effects as compared with 30 mg/kg of omeprazole but more favorable effects were observed in 200, 100 and 50 mg/kg of all YJGMB treated rats as compared with omeprazole 10 mg/kg in the present study. In addition, YJGMB 200 mg/kg were showed more favorable antioxidant effects as compared with 30 mg/kg of omeprazole in the present study. Detail mechanism studies should be conduced in future with the screening of the biological active chemical compounds in herbs.

• Journal of Internet Computing and Services
• /
• v.19 no.2
• /
• pp.17-26
• /
• 2018

Recently, through the emergence and convergence of Internet services, the unified Internet of thing(IoT) service platform have been researched. Currently, the IoT service is constructed as an independent system according to the purpose of the service provider, so information exchange and module reuse are impossible among similar services. In this paper, we propose a operation based service classification algorithm for various services in order to provide an environment of unfied Internet platform. In implementation, we classify and cluster more than 100 commercial IoT services. Based on this, we evaluated the performance of the proposed algorithm compared with the K-means algorithm. In order to prevent a single clustering due to the lack of sample groups, we re-cluster them using K-means algorithm. In future study, we will expand existing service sample groups and use the currently implemented classification system on Apache Spark for faster and more massive data processing.

• Korean Chemical Engineering Research
• /
• v.50 no.1
• /
• pp.128-134
• /
• 2012

The pilot scale experiments can handle the flue gas up to 1,000 $Nm^3/hr$ for separation of carbon dioxide included in real flue gas at coal-fired power plant. The operational characteristics was analyzed with the main experimental variables such as flue gas flow rate, absorbent circulation rate using chemical absorbents mono-ethanolamine( MEA) and 2-amino-2-methyl-1-propanol(AMP). The more flue gas flow rate decreased in 100 $m^3/hr$ in the MEA 20 wt% experiments, the more carbon dioxide removal efficiency was increased 6.7% on average. Carbon dioxide removal efficiency was increased approximately 2.8% according to raise of the 1,000 kg/hr absorbent circulation rate. It also was more than 90% at $110^{\circ}C$ of re-boiler temperature. Carbon dioxide removal efficiency of the MEA was higher than that of the AMP. In the MEA(20 wt%) experiment, carbon dioxide removal efficiency(85.5%) was 10% higher than result(75.5%) of ASPEN plus simulation.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.1159-1160
• /
• 2006

As the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, this has raised potential problems of network protection on electrical power system. One of the numerous problems is an Island phenomenon. There has been an argument that because the probability of islanding is extremely low it may be a non-issue in practice. However, there are three counter-arguments: First, the low probability of islanding is based on the assumption of 100% power matching between the PVPCS and the islanded local loads. In fact, an island can be easily formed even without 100% power matching (the power mismatch could be up to 30% if only traditional protections are used, e.g. under/over voltage/frequency). The 30% power-mismatch condition will drastically increase the islanding probability. Second, even with a larger power mismatch, the time for voltage or frequency to deviate sufficient to cause a trip, plus the time required to execute the trip (particularly if conventional switchgear is required to operate), can easily be greater than the typical re-close time on the distribution circuit. And, third, the low-probability argument is based on the study of PVPCS. Especially, if the output power of PVPCS equals to power consumption of local loads, it is very difficult for the PVPCS to sustain the voltage and frequency in an island. Unintentional islanding of PVPCS may result in power-quality issues, interference to grid-protection devices, equipment damage, and even personnel safety hazards. So the verification of anti-islanding performance is strongly needed. In this paper, the authors propose the improved RPV method through considering power quality and anti-islanding capacity of grid-connected three-phase PVPCS in IEEE Std 1547 ("Standard for Interconnecting Distributed Resources to Electric Power Systems"). And the simulation and experimental results are verified.

• STI Policy Review
• /
• v.8 no.1
• /
• pp.113-156
• /
• 2017

Although technological progress is considered a key element for economic growth and development of a country, strong empirical evidence in this regard is not available yet. Therefore, to establish the empirical link between technology progress and economic development, it is advisable to carry out a time series analysis. In this regard, the Technology Achievement Index (TAI) of 100 top economies has been developed to examine the position of countries' technological progress for the 21 years spanning 1995 to 2015. Countries have been ranked on their TAI which is based on four pillars; technology creation, diffusion of older innovations, diffusion of recent innovations, and development of human skills. As well, this current study re-calculates the Humane Development Index (HDI) of 100 top economies for the 21 years from 1995 to 2015. Ranking of countries' HDI values reflects three dimensions: A long lifespan (life expectancy index), knowledge (Education Index) and a decent standard of living (Gross National Income Index, or GNI). The Standard Deviation (SD) technique has been used to investigate the technological gap between individual countries and groups of countries or regions. For a more meaningful assessment, technological gaps from the maximum achievement value (i.e., one of the countries under study) are presented as well. To investigate the impact of technological progress on economic development, this study introduces a model in which the HDI is used as the dependent variable and the TAI and Gross Capital Formation (GCF) are used as independent variables. The HDI, TAI and GCF are used in this model as proxy variables for economic development, technological progress and capital respectively. Econometric techniques have been used to show the impact of technological progress on economic development. The results show that long-term associations exist between technology progress and economic development; the impact of technology progress on economic development is 13.2% while the impact is 4.3% higher in eight selected East South Asian countries, at 13.5%, than in eight selected highly developed countries (9.2%).

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.15 no.1
• /
• pp.22-26
• /
• 1986

This investigation was carried out to study the effect of heating treatment on the saponin fractions in ginseng extract and crude saponin. The changes of saponin patterns and amounts were investigated using HPLC and compared with peak area of each fraction. Shape of crude saponin was changed more easy to compare with in ginseng extract. The more extracting temperature risen and treated time longer, the more changes of saponin amounts and patterns were shown, expecially at $100^{\circ}C$ over. All of the saponin fraction except ginsenoside-Rd were relatively unstable in heating treatment. Suitable extracting condition was extracted at $80^{\circ}C$ for 40 hours with $H_2O$.

• Spatial Information Research
• /
• v.19 no.1
• /
• pp.73-82
• /
• 2011

Recently, demand for the use of cadastral map is increasing in both public and private area. To use cadastral map in web or mobile environment, construction of the multi-representation database(MRDB) that is the compressed into multiple scale from the original map data is recommended. In this study, the map generalization methodology for the cadastral map by applying overlay with topographic map and polygon generalization technique is suggested. This process is composed of three steps, re-constructing the network data of topographic map, polygon merging of parcel lines according to network degree, and applying line simplification techniques. Proposed methodologies are applied to the cadastral map in Suwon area. The result map was generalized into 1:5,000, 1:20,000, 1:100,000 scale, and data compression ratio was shown in 15% 8% 1% level respectively.