• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.330-335
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• 2008

This research aims to investigate the standards and the performances of domestic and foreign windows for and apartment house and to present fundamental data for selecting the optimum window at the step of designing an apartment house. To compare the performances of domestic and foreign windows it is selected 5 major window companies in and 3 major window companies in Japan, and investigated window structure, material, type of opening and closing, window glass and the performances of windows for an apartment house-closing and opening force, repeated closing and opening, thermal resistance, sound transmission loss, air tightness, water tightness, wind resistance. The result of a comparative analysis show that the average thermal resistance of Korean window is higher than Japan's but the average sound transmission loss and water tightness of Korean window is lower than Japan's and the rest of the performances is similar.

• The Research Journal of the Costume Culture
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• v.12 no.6 s.53
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• pp.945-952
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• 2004

Shrink-resist effects and properties of the knitted fabrics from wool/acrylic(W/A) fiber blends were determined to find out an optimal blending ratio keeping the quality properties of wool products. The test fabrics were knitted by a weft knitting machine with all needle knitting structure ($0{\times}0$ rib) under the same knitting conditions with five different types of yarns: $W100\%,\;A100\%$, and W/A blended yarns(70/30, 50/50, 30/70). Shrinkage during repeated washing, electrostatic propensity, thermal resistance and pilling propensity of W/A knits. The shrink resistance was significantly enhanced on repeated washing of W/A knits, especially, over $50\%$ acrylic blended knits. Addition of strong physical force and alkali detergent applied in this washing experiment brought about superior effects with the low shrinkage rate although it was very severe washing conditions for wool fabrics. The results from the washing experiment implies that W/A blend knits can be machine washed at individual households with other ordinary laundry. There was some changes and variation found in thermal resistance, electrostatic propensity, and pilling. W/A 50/50 blended knits did not bring serious changes to other physical properties comparing with original wool, which helps consumers care wool knitted clothes more conveniently.

• Fashion & Textile Research Journal
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• v.18 no.1
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• pp.113-119
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• 2016

The evolution of spinning technology was focused on improving productivity with good quality of yarns. More detail spinning technology according to mixing of various kinds of fibre materials on the air vortex spinning system is required for obtaining good quality yarns. This paper investigated the physical properties of air vortex yarns compared with ring and compact yarns using PTT/tencel/cotton fibres. It was observed that unevenness of air vortex yarns was higher than those of ring and compact yarns, which resulted in low tenacity and breaking strain of air vortex yarns. Initial modulus of air vortex yarns was higher than those of ring and compact yarns. Yarn imperfections of air vortex yarns such as thin, thick and nep were much more than those of ring and compact yarns. These poor yarn qualities of air vortex yarn were attributed to the fasciated yarn structure with parallel fibres in the core part of the air vortex yarn. However, yarn hairiness of air vortex yarns was less and shorter than those of ring and compact yarns. Thermal shrinkage of air vortex yarns were higher than that of ring yarns, which was caused by sensible thermal shrinkage of PTT fibres on the bulky yarn surface and core part of air vortex yarns.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.5
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• pp.459-467
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• 2005

The effect of anti freezing solution liquid film on the frost prevention is experimentally investigated. It is desirable that the antifreezing solution spreads widely on the heat exchanger surface forming thin liquid film to prevent frost nucleation and reduce the thermal resistance across the film. A porous layer coating technique is adopted to improve the wettedness of the anti freezing solution on a parallel plate heat exchanger. The antifreezing solution spreads widely on the heat exchanger surface with 100 $\mu$m thickness by the capillary force resulting from the porous structure. It is observed that the antifreezing solution liquid film prevents a parallel plate heat exchanger from frosting. The reductions of heat and mass transfer rate caused by thin liquid film are only $1\~2\%$ compared with those for non-liquid film surface.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1857-1862
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• 2008

Resonant frequency tuning of micro devices is essential to achieve performance uniformity and high sensitivity. Previously reported frequency tuning methods using electrostatic force or mass deposition are not directly applicable to non-conducting polymer devices and have limitations such as dielectric breakdown or low tunable bandwidth. In this paper, thermally frequency-tunable microactuators with poly-dimethylsiloxane membranes are proposed. Permanent and/or nonpermanent frequency tunings are possible using a simple temperature control of the device. Resonant frequency and Q-factor variations of devices according to temperature change were studied using a micro heater and laser Doppler vibrometer. The initial resonant frequencies determined by polymer curing and hardening temperatures are reversibly tuned by thermal cycles. The measured resonant frequency of 9.7 kHz was tuned up by ${\sim}25%$ and Q-factor was increased from 14.5 to 27 as the micro heater voltage increased from 0 to 70 V.

• Fibers and Polymers
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• v.6 no.2
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• pp.169-173
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• 2005

Low temperature plasma (LTP) treatment was applied to wool fabric with the use of a non-polymerizing gas, namely oxygen. After the LTP treatment, the fabric properties including low-stress mechanical properties, air permeability and thermal properties, were evaluated. The low-stress mechanical properties were evaluated by means of Kawabata Evaluation System Fabric (KES-F) revealing that the tensile, shearing, bending, compression and surface properties were altered after the LTP treatment. The changes in these properties are believed to be related closely to the inter-fiber and inter-yam frictional force induced by the LTP. The decrease in the air permeability of the LTP-treated wool fabric was found to be probably due to the plasma action effect on increasing in the fabric thickness and a change in fabric surface morphology. The change in the thermal properties of the LTP-treated wool fabric was in good agreement with the above findings and can be attributed to the amount of air trapped between the yams and fibers. This study suggested that the LTP treatment can influence the final properties of the wool fabric.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.2
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• pp.55-62
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• 2016

The air flows in building caused by thermal buoyancy, known as the stack effect, have a pronounced influence on both the indoor environment (thermal environment, noise, draught and contaminant diffusion) and energy needs in high-rise buildings. Prior studies for airflow in high-rise buildings were focused on the degree of stack effect and countermeasures. The wind pressure was neglected during the calculation of the indoor airflow in high-rise buildings to clarify the effect of thermal buoyancy in previous studies. However, wind is an important driving force of indoor airflows in buildings with the stack effect. In this study, the effect of wind pressure on indoor airflow in high-rise building when the stack effect is dominant in winter was analyzed. In this paper, methods that involved considering the wind pressure in airflow network simulation were analyzed.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.120-121
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• 2007

In this paper, ZnO thin films were deposited by pulsed laser deposition (PLD) on $Al_2O_3$ (alumina) at room temperature in various $O_2$ ambient. Rapid thermal annealing (RTA) has been performed at temperatures from $400^{\circ}C$ to $700^{\circ}C$. The effects of temperature and ambient on the structural property of ZnO films were examined by x-ray diffractometer (XRD) and atomic force microscopy (AFM), respectively. The results show that the (002)-oriented ZnO thin films on non-single crystal alumina were obtained in over 30mTorr ambient at all RTA temperatures including room temperature. The foil-width half maximum (FWHM) of (002) peak decreases as the RTA temperature increases, which indicates that ZnO thin films with RTA have improved crystalline quality.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.500-501
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• 2005

Aluminum doped zinc oxide films (ZnO:Al) were deposited on glass substrate by DC magnetron sputtering from a ZnO target mixed with 2 wt% $Al_2O_3$. The effects of substrate bias on the electrical properties and film structure were studied. Films deposited with positive bias have been annealed at $600^{\circ}C$ using rapid thermal anneal (RTA) process. The effects of RTA on the evolution of film microstructure are to be also studied using X-ray diffraction, transmission electron microscopy, and atomic force microscopy. Positive bias sputtering may induce lattice defects caused by electron bombardments during deposition. The as-deposited film microstructure evolves from the film with high defect density to more stable film condition. The electrical properties of the films after RTA process were also studied and the results were correlated with the evolution of film microstructures.

• Advances in nano research
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• v.5 no.2
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• pp.69-97
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• 2017

In this study, nonlinear response of laminated functionally graded carbon nanotube reinforced composite (FG-CNTRC) plate under low-velocity impact based on the Eshelby-Mori-Tanaka approach in thermal conditions is studied. The governing equations are derived based on higher-order shear deformation plate theory (HSDT) under von $K\acute{a}rm\acute{a}n$ geometrical nonlinearity assumptions. The finite element method with 15 DOF at each node and Newmark's numerical integration method is applied to solve the governing equations. Four types of distributions of the uniaxially aligned reinforcement material through the thickness of the plates are considered. Material properties of the CNT and matrix are assumed to be temperature dependent. Contact force between the impactor and the laminated plate is obtained with the aid of the modified nonlinear Hertzian contact law models. In the numerical example, the effect of layup (stacking sequence) and lamination angle as well as the effect of temperature variations, distribution of CNTs, volume fraction of the CNTs, the mass and the velocity of the impactor in a constant energy level and boundary conditions on the impact response of the CNTRC laminated plates are investigated in details.