• Journal of Powder Materials
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• v.21 no.5
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• pp.366-370
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• 2014

The present study demonstrates the effect of solidification condition on the pore structure in freeze drying process using the slurries of CuO/sublimable vehicles. Camphene and Camphor-45 wt% naphthalene based slurries with 14 vol% CuO powder were frozen into a mold at $-25^{\circ}C$, followed by sublimation at room temperature. The green bodies were hydrogen-reduced and sintered at $500^{\circ}C$ for 1 h. The porous Cu specimen, frozen the CuO/camphene slurry into the heated mold of the upper part, showed large pores with unidirectional pore channels and small pores in their internal wall. Also, it was observed that the size of large pores was decreasing near the bottom part of specimen. The change of pore structure depending on the freezing condition was explained by the nucleation behavior of camphene crystals and rearrangement of solid powders during solidification. In case of porous Cu prepared from CuO/Camphor-naphthalene system, the pore structure exhibited plate shape as a replica of the original structure of crystallized vehicles with hypereutectic composition.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.117-122
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• 2008

The apartment will be much more convenient than the other one in the application of green technologies, providing the merits by mass production. For example, pre-manufactured building materials can be effectively adapted to the formation of buildings. Recently, the form of double-enveloped window system has been developed for the purposed of minimizing energy loss occurred around windows. On the other hand, the expansion of balcony area was legalized and thus, a visual buffer area does not exist any more. All-glass window wall on apartment houses without a balcony produces pretty harmful area with direct sunbeam. A various types of glass can be applied to the window system and it plays a critical role in the determination of inner visual environment. For the purpose of verifying the potential of its daylighting, a mock-up model has been constructed and tested. The refurbished version of conventional window shows its illuminated characteristics. Clear and Low-e glass have been adapted for window area and daylighting ratio has been compared in both test cells.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.292-303
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• 2006

The Volatile Organic Compounds(VOCs) are emitted from various sources and have lots of different form. Recently human are spending the many times at indoor area and indoor air pollution is issued the important social problem. The emission sources of indoor air pollutants are very various, also indoor building materials are composed of very complex chemical compounds, these indoor building materials discharge very much VOCs and other hazardous compounds. In this study, we performed the small chamber test to investigate the VOCs emission concentration and characteristics involving five kinds of the indoor building materials(furniture material, wooden floor, wall paper, paint and tile) under different conditions of four temperature and relative humidity as account of the air flow rate(AFR), air exchange rate(AER), loading factor and air velocity respectively. As the result, It was showed that building materials are emitted the highest VOCs concentration at the beginning of experiment and furniture material is emitted the highest VOCs concentration. Most of the materials were affected by temperature, but paint and tile material were affected by humidity.

• KIEAE Journal
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• v.17 no.3
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• pp.99-106
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• 2017

Purpose: Most modern office buildings adopt the curtain wall system in order to provide occupants with the sense of openness and high-technology, which requires large window area. As a result, the amount of solar radiation increases, negatively affecting cooling load during the summer and increasing energy costs. However, the performance of window itself is not sufficiently controllable parameter to control thermal comfort and solar radiation. Therefore, a shading device such as venetian blind is required to control them and thus a variety of studies have been performed thus far. So, the purpose of this study is to improve the performance of blind through the development of blind control algorithm. Method: Among various input variables for the control of venetian blinds, the vertical solar radiation has been selected in this study as the primary input variable and the optimal control algorithm for venetian blinds were developed for each window orientation. Result: The developed optimal control algorithm has a positive effect on building energy savings.

• Journal of Biosystems Engineering
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• v.28 no.1
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• pp.35-44
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• 2003

This study was conducted to develop proper model for cold storage facility that could of for uniform heat movement and air movement f3r green grocery and improve improper design of the existing container-type cold storage facility. For that reason, new model(dome-type) cold storage facility was developed using 3-D CFD(computational fluid dynamics) simulation. The size was 6m${\times}$6m${\times}$5m. Its size and configuration were same to simulation model. Unit cooler was designed to send cold air in 4 side ways. A dome-type cold storage facility showed uniform distributions of air temperature and velocity because cold air was forced to move down along the ceiling and the wall and then circulated to the unit cooler from the central part of the floor. Dome-type cold storage facility also showed by low wind velocity, below 1 m/s that could minimized cold damage and quality deterioration.

• Journal of Powder Materials
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• v.19 no.4
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• pp.259-263
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• 2012

Dependence of the freeze-drying process condition on microstructure of porous W and pore formation mechanism were studied. Camphene slurries with $WO_3$ contents of 10 vol% were prepared by milling at $50^{\circ}C$ with a small amount of dispersant. Freezing of a slurry was done in Teflon cylinder attached to a copper bottom plate cooled at $-25^{\circ}C$. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green body was hydrogen-reduced at $800^{\circ}C$ for 30 min, and sintered in the furnace at $900^{\circ}C$ for 1 h. After heat treatment in hydrogen atmosphere, $WO_3$ powders were completely converted to metallic W without any reaction phases. The sintered samples showed large pores with the size of about $70{\mu}m$ which were aligned parallel to the camphene growth direction. Also, the internal wall of large pores and near bottom part of specimen had relatively small pores with dendritic structure due to the growth of camphene dendrite depending on the degree of nucleation and powder rearrangement in the slurry.

• KSBB Journal
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• v.5 no.1
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• pp.43-47
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• 1990

It was determined optimal Culture conditions and suitable growth regulators for seed germination, growth of callus, and protoplasts derived from cultured and mesophyll cells in Gremastra appendiculata. Induction of fusion between protoplasts of cultured and mesophyll cells was examined. The best conditions of seed germination and growth of callus were achieved on Hyponex medium contained plant growth regulators(2mg/l 2, 4-D, lmg/l Kinetin). Viability and regeneration of cell wall in protoplasts was determined with fluorescence microscope. Also, fused protoplasts were achieved by using PEG solution between protoplasts of cultured and mesophyll cells.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.79-84
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• 2018

In the present study, we performed electroporation to deliver protein into microalgae using previously developed digital electroporation system. Green fluorescence protein was successfully delivered into a live microalgae cell nucleus without cell wall removal. By investigating the effects of applied voltage on the protein delivery efficiency, optimal electroporation electric field condition was found (960 V/cm). We also investigated the delivery of Yo-Pro-1 into cell to examine the size effects of delivered materials and found that there is little size effects on the optimal condition. Finally, the implications of the present results and future work are discussed.

• Korea-Australia Rheology Journal
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• v.15 no.2
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• pp.83-90
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• 2003

In cases of the microfluidic channel, the electrokinetic influence on the transport behavior can be found. The externally applied body force originated from the electrostatic interaction between the nonlinear Poisson-Boltzmann field and the flow-induced electrical field is applied in the equation of motion. The electrostatic potential profile is computed a priori by applying the finite difference scheme, and an analytical solution to the Navier-Stokes equation of motion for slit-like microchannel is obtained via the Green's function. An explicit analytical expression for the induced electrokinetic potential is derived as functions of relevant physicochemical parameters. The effects of the electric double layer, the zeta potential of the solid surface, and the charge condition of the channel wall on the velocity profile as well as the electroviscous behavior are examined. With increases in either electric double layer or zeta potential, the average fluid velocity in the channel of same charge is entirely reduced, whereas the electroviscous effect becomes stronger. We observed an opposite behavior in the channel of opposite charge, where the attractive electrostatic interactions are presented.

• ALGAE
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• v.28 no.2
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• pp.185-192
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• 2013

A new cold-adapted Arctic strain of Haematococcus pluvialis from Blomstrandhalv${\o}$ya Island (Svalbard) is described. This strain is predominantly always in non-motile palmelloid stage. Transmission electron microscopy showed the presence of very thick cell wall and abundant lipid vesicles in the palmelloids, including red and green cells. The external morphology of the non-motile palmelloid and motile bi-flagellated cells of our strain is similar to H. pluvialis; however it differs from H. pluvialis in physiology. Our strain is adapted to live and produce astaxanthin in the low temperature ($4-10^{\circ}C$), whilst the usual growth temperature for H. pluvialis is between $20-27^{\circ}C$. Phylogenetic analysis based on 18S rRNA gene data showed that our strain nested within the Haematococcus group, forming a sister relationship to H. lacustris and H. pluvialis, which are considered synonymous. Therefore, we identified our Arctic strain as H. pluvialis.