• Journal of Powder Materials
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• v.12 no.4 s.51
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• pp.255-260
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• 2005

Direct solid state synthesis by hot pressing has been applied in order to produce high efficiency $Zn_4Sb_3$ bulk specimens. Single phase $Zn_4Sb_3$ with 98.5% of theoretical density was successfully produced by direct hot pressing of elemental powders containing 1.2 at.% excess Zn. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of other studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by direct synthesis were measured and are comparable to the published data. Direct solid state synthesis by hot pressing provides a promising processing route in this material.

• Journal of the Korean Ceramic Society
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• v.30 no.2
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• pp.157-163
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• 1993

Hot pressing after cold cyclic compaction of Al2O3 powder mixtures containing SiC whiskers or Al2O3 short fibers is studied with emphasis on the effects of cold cyclic compaction. The green density of the mixtures increases as the cycle number increases and the cyclic pressure becomes higher. The higher green density is also obtained by cold cyclic compaction with the lower pressrue than a single stroke cold compaction. To achieve a higher densification during hot pressing, cold cyclic compaction before hot pressing is more efficient compared to the conventional hot pressing process (without cold cyclic compaction). Moreover, a low cyclic pressure did not affect on toughening mechanism by whisker reinforcement.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.531-536
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• 2003

Equal channel angular pressing (ECAP) has been employed to produce materials with ultra-fine grains that have high strength and high corrosion resistance properties. In order to obtain super plastic deformation during ECAP, multipass angular pressing is frequently employed. In this paper, three-dimensional finite element analyses have been performed to investigate the deformation behavior of pure-Zr specimen and the effects of process parameters for equal channel multi-angular pressing (ECMAP) process. The results have been compared with some experimental results

• Journal of the Korea Furniture Society
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• v.25 no.2
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• pp.96-103
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• 2014

The objective of this study was to increase the utilizability of domestic thinning and small diameter wood as applying in pattern design which can be used in interior decoration, wood craft and wood furniture, and in developing the designs of furniture and household items. We investigated the physical and mechanical characteristics of Betula platyphylla Wood by pressurization and heat treatment. Color change is clear, and the wood density is increased with increasing pressing rate. The compressive strength, modulus of rupture and modulus of elasticity in bending strength are decreased as heating time is increased after pressing. However, shrinkage is improved after pressing and heating.

• Journal of the Korean Wood Science and Technology
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• v.25 no.1
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• pp.50-55
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• 1997

This study was carried out to utilize old newspaper(ONP) and paper sludge more effectively, and also to elucidate the influences of pressing conditions on the medium density fiberboard(MDF) properties. MDFs were made from ONP and low grade of paper sludge by wet process with change of pressing time, temperature and pressure. MDFs of ONP were more affected by pressing conditions, especially pressing pressure, but temperature and pressing time were also important. According to mixing paper sludge to ONP tensile and bending strength of MDF were decreased, but density and dimensional stability were improved. These results indicated that some physical properties of MDF can be improved by paper sludge and it is possible to use it in MDF.

• 연구논문집
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• s.33
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• pp.147-155
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• 2003

In order to fabricate porous materials having an anisotropic thermal conductivity by aligning plate-shaped pores structure, alumina powder (AM-21, mean particle size $4\mum$) and flake crystalline graphite was used. The aligned pore structure was realized using multi-pressing process. Degree of pore orientation increased with the number of pressing and thermal conductivity, parallel to the pressing direction, decreased with the number of pressing. Thermal conductivity decreased significantly to the addition of 30vol% crystalline graphite, however, in the case of 60vol%, thermal conductivity did not decrease significantly due to the breakage of crystalline graphite. An anisotropy of the thermal conductivity increased with the content of crystalline graphite up to 30vol%. Graded pore structure was fabricated by controlling the content and size of crystalline graphite, which provides, possibly, the enhancement in mechanical strength and thermal insulation properties of the insulating bricks.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.421-424
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• 2000

We have examined the impedance characteristics and the rate characteristics of LPB. As results, the impedance of LPB decreased with increased pressing rate of electrodes, adding amounts of PVdF and VGCF. And the rate characteristics of LPB increased with the a increase of pressure-rate, PVdF and VGCF contents. The rate characteristics of LPB was improved by pressing of electrode and adding of VGCF content. And specific capacity of anode was increased with adding amounts of PVdF. Higher pressing rate of electrodes, higher adding amounts of PVdF and VGCF was necessitated good rate characteristics for lithium polymer battery.

• Journal of the Korea Furniture Society
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• v.20 no.5
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• pp.490-503
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• 2009

The objective of this work was to investigate the mechanism of heat transfer in hot-pressing process for MDF manufacturing by reference study. Firstly, general heat transfer theory was studied. The numerical analysis of heat transfer in hot-pressing process was studied on temperature profile, moisture profile, physical properties between moisture and board. The mechanism of heat and moisture transfer inside of board was analyzed by conduction, convection, radiation and diffusion of bound water in wood cell walls. Especially, the change of core temperature as hot press time was important factor to setup hot-pressing schedule in MDF manufacturing.

• Transactions of Materials Processing
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• v.11 no.6
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• pp.519-528
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• 2002

The microstructural evolution during the equal channel angular pressing of Ti-6Al-4V alloy was investigated using the transmission electron microscopy (TEM). ECA pressing was carried out isothermally with route C at $600^{\circ}C$ for two types of initial microstructure, i.e., equiaxed and Widmanstatten microstructures. At an initial stage of ECA pressing, the equiaxed microstructure showed more uniform flow than the Widmanstatten microstructure. However, both microstructures were significantly refined revealing nearly equiaxed grains of 0.3$mu extrm{m}$ in diameter with high angle grain boundaries after 4 passes of ECA pressing. These ultrafine gains were found to be stable with little grain growth, when annealed up to $600^{\circ}C$ for 1hr.

• Journal of the Semiconductor & Display Technology
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• v.16 no.4
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• pp.52-58
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• 2017

In this study, we tried to analyze and measure the correlation between the part dimensional tolerance empirically applied by the designer and the final performance of the equipment, which is expressed as the pressing pressure uniformity. For this purpose, the dimensional tolerances and pressing pressure uniformity of eight laminator equipments were measured actually. As a result of the correlation analysis, it was confirmed that the tolerance grade for each dimension determined by the designer was valid. In the case of laminator equipment, the driving parts and the flatness have the largest influence on the uniformity of the pressing pressure.