• Journal of Welding and Joining
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• v.34 no.3
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• pp.52-60
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• 2016

Recently nickel based superalloys are extensively being regarded as the materials for the steam turbine parts for hyper super critical (HSC) power plants working at the temperature over $700^{\circ}C$, since the materials have excellent strength and corrosion resistance in high temperature. In this paper, alloy 617 of solution strengthened material and alloy 263 of ${\gamma}^{\prime}$-precipitation strengthened material were prepared as the testing materials for HSC plants each other. Post weld heat treatment (PWHT) was conducted with the gas tungsten arc (GTA) welded specimens. The microstructure of the base metals and weld metals were investigated with Electron Probe Micro-Analysis (EPMA) and Scanning Transmission Electron Microscope (STEM). The experimental results revealed that Ti-Mo carbides were formed in both of the base metals and segregation of Co and Mo in both of the weld metals before PWHT and PWHT leaded to precipitation of various carbides such as Mo carbides in the specimens. Furthermore, fine ${\gamma}^{\prime}$ particles, that were not precipitated in the specimens before PWHT, were observed in base metal as well as in the weld metal of alloy 263 after PWHT.

• The Journal of Sustainable Design and Educational Environment Research
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• v.17 no.1
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• pp.1-11
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• 2018

The aims of this research are investigating and analysing background, enforcement situation, distinct features and current status of green schools which have been conducted by the government targeting decrepit schools. Based on this investigation and analysis the solution for vitalizing green schools will be sought because green schools are more effective in reducing energy and greenhouse gas and they are more appropriate methods for schools. With internal and external literature reviews the concept and background of overseas green school policies and their similarities and differences are analyzed. Based on the investigation into current status of green schools in Korea and eco-schools and super eco-schools in Japan which are benchmarking objects of green schools project in Korea the problems and outcomes of green schools in Korea are diagnosed. By analyzing cases of eco-schools and super eco-schools in Japan implications for introducing to Korea are considered. Based on the aforementioned researches this study suggests the improvement plan for vitalizing green schools project and similar projects.

• Fashion & Textile Research Journal
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• v.19 no.3
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• pp.331-336
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• 2017

Bacteria exist everywhere and continuously come into contact with daily surroundings and humans. Super bacterium methicillin-resistant Staphylococcus aureus, resistant to methicillin, has recently appeared. The morbidity and rate of death associated with super bacteria infection has increased. This study investigated the antibacterial activity of fabrics naturally dyed with Chamaecyparis obtusa leaves extract against methicillin-resistant Staphylococcus aureus. Fabrics were left for 15 min in a natural dyeing solution prepared by extraction from C. obtusa leaves using 11.3% (o.w.f) with a fixed liquor ratio of 1:22 at $40^{\circ}C$. The dyeing process was conducted using three different mordants; subsequently, the K/S value of the dyed fabrics increased in the order of None < Cu < Fe < Al. The color fastness property of the fabrics to washing, dry-cleaning, and rubbing was found to be excellent and ranked in the 4-5 grade. The color fastness to light of natural dyeing is low in most cases and has the problem that the dye color soon becomes bleached. Yet, in most cases cloth dyed with retinispora leaves, the color fastnezz to light was good with a third to fourth grade. Non-mordant fabrics, aluminum mordants, and copper mordants also showed better antibacterial properties (99.9% reduction) against methicillin-resistant Staphylococcus aureus, compared to the control fabrics. The dyed fabrics showed the same antibacterial activity even after three washes. The results highlight the strong potential of fabrics naturally dyed with C. obtusa-extract as a medicinal material with excellent antibacterial function against methicillin-resistant Staphylococcus aureus.

• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.126-132
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• 2011

Recently, high-rise apartment is being briskly built but there are problems such as lack of ventilation, stack effect and much energy consumption. Therefore It is recommended to develop a Small Wind Power System Combined Ventilator as a solution to solve these problems. The purpose of this study is to provide basis for Small Wind Power System Combined Ventilator in super high-rise apartment. This study conducted CFD simulation (Star-CCM) according to the shape of structures, building height and distance of two structures to identify the effect of wind speed increase when the structure is installed. As a result, pyramidal type was best suited for increase of wind speed. The best place was the front of the roof to main wind direction, and the best building height was 200m rather than 300m. If two or more small wind turbines combined ventilator are installed closely, vertical position to main wind direction is recommended. Horizontal position must necessarily be avoided, but height difference between two blades more than 3m showed good performance.

• Wind and Structures
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• v.18 no.6
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• pp.693-715
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• 2014

Stochastic processes are used to represent phenomena in many diverse fields. Numerical simulation method is widely applied for the solution to stochastic problems of complex structures when alternative analytical methods are not applicable. In some practical applications the stochastic processes show non-Gaussian properties. When the stochastic processes deviate significantly from Gaussian, techniques for their accurate simulation must be available. The various existing simulation methods of non-Gaussian stochastic processes generally can only simulate super-Gaussian stochastic processes with the high-peak characteristics. And these methodologies are usually complicated and time consuming, not sufficiently intuitive. By revealing the inherent coupling effect of the phase and amplitude part of discrete Fourier representation of random time series on the non-Gaussian features (such as skewness and kurtosis) through theoretical analysis and simulation experiments, this paper presents a novel approach for the simulation of non-Gaussian stochastic processes with the prescribed amplitude probability density function (PDF) and power spectral density (PSD) by amplitude modulation and phase reconstruction. As compared to previous spectral representation method using phase modulation to obtain a non-Gaussian amplitude distribution, this non-Gaussian phase reconstruction strategy is more straightforward and efficient, capable of simulating both super-Gaussian and sub-Gaussian stochastic processes. Another attractive feature of the method is that the whole process can be implemented efficiently using the Fast Fourier Transform. Cases studies demonstrate the efficiency and accuracy of the proposed algorithm.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.73-79
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• 1968

The resolving capacities of xanthophyll pigments on thin-layers of Silica Gel, Hyflo super-Cel, and Micro-Cel C with varying concentrations of acetone in petroleum ether as the developing solvent were compared. The results showed that the resolving capacity of Micro-Cel C thin-layer was superior to others and satisfactory for the separation of leaf carotenoids in clearly separated six bands; carotenes, lutein-zeaxanthin, antheraxanthin, violaxanthin, an unidentified band, and neoxanthin, when it was developed with $13\%$ acetone-petroleum ether solution for 15 to 20minutes in an unsaturated chamber. Adhension of Micro-Cel C to glass was adequate without binder. Calcium sulfate used as a binder appeared to inactivate the resolving capacity of Micro-Cel C. Removing an about 0.2cm-wide layer on bo side of thin-layer slide helped to prevent 'edge effect' which gave tailing and faster solvent ascending along the side than the center. An adequate thickness of thin-layer was obtained when a 3 ml aliquot of the suspension in which l0g powdered Micro-Cel C was suspended in 75 ml distilled water was coated on a $2\times20cm$ glass slide.

• Journal of the Korean Society of Clothing and Textiles
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• v.9 no.2
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• pp.75-84
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• 1985

In order to improve dyeing and finishing technology of thin cloth of microfiber(super-fine fiber), the degrees of deep dyeing method, the light fastness, and the washing fastness were investiagted. 1. The thin cloth made of microfiber, $0.15^d\~0.2^d$, was conjugated type and the dyeing degree was lower at 5 to $10\%$ than that of cloth made of common fiber. The cloth of excellent dyeing fastness, light fastness, was developed by increasing the concentration of dye of high quality up to $5\~10\%$. 2. Because refractory rate of microfiber of $0.2^d$ was lower than that of $0.01^d$, the surface refractory rate of $0.2^d$ was lower than that of $0.01^d$ fiber. Therefore the surface of micro-fiber, $0.2^d$, was more rougher than that of $0.01^d$ and it belongs to separate type. 3. The higher degree of dyeing was increased by using dye of microparticle. Also the degree of textile printing was increased by adding urea solution ($20\%$) and glycerine diethylene glycol. 4. Light fastness was very excellent, marked 5 grade. However, washing fastness was 2$\~$3 grade. After dyeing, we could improve to 4 grade, through hot water washing including some organic chlorine solvent. 5. Super microfiber of $0.01^d$ will not be dyed by present dye and dyeing equipment, because right reflection light rate(white light) of fiber surface was too high and the more refraction rate higher the more surface refraction rate will be increased.

• Smart Structures and Systems
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• v.6 no.8
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• pp.939-951
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• 2010

A low-cost wireless sensor network (WSN) solution with highly expandable super and simple nodes was developed. The super node was designed as a sensing unit as well as a receiving terminal with low energy consumption. The simple node was designed to serve as a cheaper alternative for large-scale deployment. A 12-bit ADC inputs and DAC outputs were reserved for sensor boards to ease the sensing integration. Vibration and thermal field tests of the Chi-Lu Bridge were conducted to evaluate the WSN's performance. Integral acceleration, temperature and tilt sensing modules were constructed to simplify the task of long-term environmental monitoring on this bridge, while a star topology was used to avoid collisions and reduce power consumption. We showed that, given sufficient power and additional power amplifier, the WSN can successfully be active for more than 7 days and satisfy the half bridge 120-meter transmission requirement. The time and frequency responses of cables shocked by external force and temperature variations around cables in one day were recorded and analyzed. Finally, guidelines on power characterization of the WSN platform and selection of acceleration sensors for structural health monitoring applications were given.

• Journal of National Security and Military Science
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• s.4
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• pp.241-287
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• 2006

16th CPC National Party Congress established multi-polarization strategy as an external strategy, and 'The Great Reinvigoration of Chinese Nation' as the aim of The Great Strategy of China. It is required to maintain stabilized and peaceful surrounding circumstance in order to make it possible. The ideal surrounding circumstance that China is aiming for is to achieve multi-polarization of international society while maintaining strategic deterrence. Multi-polarization now in 'One super Multi powers' is that 'Multi powers' deter 'One super' to prevent predominance of USA and to decentralize the power. China wishes to realign international order as it accomplishes multi-polarization. China who wants 'Peace and Stabilization' emphasizes autonomy, peace and unification of Korean peninsula. Autonomy means the restraint intervention of foreign power, that is, American influence in Korean peninsula. Multi-polarization strategy of China will be used in Korean peninsula to solve nuclear issue of North Korea, to support neutral unification and to keep balance of power with USA, Japan and Russia as it renders economic advantages to South Korea and security engagement to North Korea, based on special geographical, cultural and historical relationship with two Koreas. The nuclear issue of North Korea will be a stage to test multi-polarization of China. When it deduces positive solution of nuclear issue due to successful six-party talks, and advances to security talks of Northeast Asia, it will contribute a lot to power and elevation of national stature of China in international society. Thus, the Chinese strategy will be an accommodative condition for the security of South Korea, and it requires wise decision of South Korea to make hay while the sun shine.

• Korean Journal of Materials Research
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• v.25 no.8
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• pp.403-409
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• 2015

Metastable phase characteristics of beta Ti alloys were investigated to consider the relationship of the microstructure and diffraction pattern in TEM. TEM analysis showed that the microstructure was mottled as a modulated structure, and the diffraction pattern was composed of spot streaks between the main spots of a stable beta phase with a specific lattice relationship. The modulated structure may be induced by short distance slip or atom movement during a very short interval of solution treated and quenched (STQ) materials. The athermal ${\omega}$ phase, which could be precipitated at low temperature aging, is also analysed by the metastable phase. The metastable phases including athermal ${\omega}$ phase had a common characteristic of hardened and brittle behavior because the dislocation slip was restricted by a super lattice effect due to short distance atom movement at the metastable state.