• Applied Microscopy
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• 제45권4호
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• pp.218-224
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• 2015

A technical overview on the various sample preparation methods for electron backscattered diffraction (EBSD) analysis is carried out. The mechanical polishing with colloidal silica finish, electro-chemical polishing, dual layer coating and ion beam milling are introduced for the common sample preparation methods for EBSD observation and some issues that are frequently neglected by the common EBSD users but should be considered to get a reliable EBSD data are discussed. This overview would be especially helpful to the people who know what EBSD technique is but do not get a reliable EBSD data because of difficulties in sample preparation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• 제48권2호
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• pp.68-74
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• 2016

Nanofibrillated cellulose (NFC) was prepared from cotton linter after electron beam irradiation to investigate its effects on the manufacturing efficiency of the NFC preparation and the property changes by the treatment. Mechanical device (Super Masscolloider) was used to prepare the NFC and its passing frequency for each NFC preparation was recorded. More electron beam irradiation resulted in less passing frequency. Alpha cellulose content, molecular weight, crystallinity index, and thermal decomposition behavior of each treatment were lowered by electron beam treatment (10 and 100 kGy) and grinding process. NFC films were prepared to investigate their mechanical properties. There were little changes in tensile properties of the NFC films.

• Composites Research
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• 제28권2호
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• pp.40-45
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• 2015

The purpose of the present work was to preparation and study of full biodegradable Eco-friendly bio-composites by using renewable resources. In this study, wheat protein isolate (WPI) films were formed by cross linking with resorcinol through solution casting method for packaging applications. By varying the resorcinol content (10, 20, 30, 40, and 50 wt %), its effect on mechanical properties of the wheat protein isolate film was measured. The addition of 20% resorcinol led to an overall increase in the tensile strength from 5.2 to 18.6 MPa and modulus increase from 780 to 1132 MPa than WPI films. The % elongation was increased from 2.8 to 9.05 when compared to unmodified WPI film. A thermal phase transition of the prepared WPI was assessed by means of DSC. FTIR is evident that the characteristic WPI spectral IR bands shifted on cross-linking with resorcinol.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제34권12호
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• pp.1785-1791
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• 2010

This paper describes a separable microfluidic device fabricated with PDMS (polydimethylsiloxane) and glass. The device is used for sample preparation involving cell lysis and the DNA purification process. The cell lysis was performed for 2 min at $80^{\circ}C$ in a serpentine-type microreactor ($20 {\mu}l$) using a Au microheater that was integrated with a thermal microsensor on a glass substrate. The DNA that was mixed with other residual products during the cell lysis process was then filtered through a new filtration system composed of microbeads (diameter: $50 {\mu}m$) and PDMS pillars. Since the entire process (sample loading, cell lysis reaction, DNA purification, and sample extraction) was performed within 5 min in a microchip, we could reduce the sample preparation time in comparison with that for the conventional methods used in biochemistry laboratories. Finally, we verified the performance of the sample preparation chip by conducting PCR (polymerase chain reaction) analysis of the chip product.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.216-219
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• 2004

Due to the recent amazing achievements in nano technology. preparation of cement nano particles by mechanical method are examined to improve their properties. The experimental results show that the particle size after 3 hr milling were about 500nm. The SEM photographs of specimens also reveal that average sizes of cement particles are gradually decreased by milling time. And in the TG/DSC, influence of the alcohol is showed strongly. The value of TG of the crushed cement was larger than that of the non-crushed cement. That is also judged to be cause the alcohol.

• Korean Journal of Metals and Materials
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• 제48권8호
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• pp.730-740
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• 2010

Aluminum, magnesium, titanium and high Mn steel are difficult to use in electron backscatter diffraction (EBSD) sample preparation due to the formation of an oxidation layer under conventional polishing. Alcohol-based polishing with colloidal silica suspension was introduced for these delicate samples. A hard particle-embedded sample was analyzed successfully using mechanical polishing. Ion-milling was effective in removing oxidized, deformed and transformed layers after mechanical polishing and was able to reduce artifacts significantly. The microstructure of a cross-section of a thin copper film was evaluated by attachment of a dummy to the film for mechanical polishing.

• Elastomers and Composites
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• 제50권1호
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• pp.35-48
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• 2015

Polyhedral oligomeric silsesquioxane (POSS) is an important inorganic-organic hybrid material with a three-dimensional structure. Polyurethane (PU) is a widely applied polymer that has versatile properties with the change of two phase structure. When POSS is incorporated into PU by physical or chemical methods, many properties can be greatly improved, such as mechanical properties, thermal stability, biodegradation resistance, and water resistance. This paper reviews the recent progress in preparation, structure, and performance of POSS-modified polyurethane from the viewpoint of physical blending and chemical modification.

• The Journal of the Korean dental association
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• 제57권7호
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• pp.380-391
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• 2019

In recent years, with the introduction of various restorative materials, restorations using CAD/CAM equipment have been increasing in the esthetic dentistry. The critical steps in the fabrication of indirect restorations with CAD/CAM equipment are proper cavity preparation and making accurate impressions. The process of tooth preparation for CAD/CAM restoration should include a mechanical understanding of milling. In addition, during tooth preparation, the clinician should be familiar with additional equipment and techniques for obtaining the convenience. In order to obtain an accurate oral scan, the clinician should understand the limitations of the oral scan and be skilled at techniques for obtaining a successful image when making oral scans. This article focused clinical guidelines for the preparation of CAD/CAM restorations and introduced clinical methods for making successful impression of oral scans in narrow and deep tooth cavity areas.

• Journal of the korean academy of Pediatric Dentistry
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• 제32권1호
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• pp.164-173
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• 2005

Mechanical preparation has been introduced to provide the sealant retention. The objective of this study was to compare the fissure penetration and the microleakage of pit and fissure sealant using mechanical preparation(mechanical preparation + acid etching) and acid etching only. An additional objective of this study was to compare the fissure penetration and the microleakage of unfilled and filled sealant in both methods. Sixty human premolars extracted for orthodontic purpose were selected. Thirty teeth were acid etched alone and remaining thirty teeth were prepared with a $\frac{1}{4}$ round bur and then acid etched. One-half of teeth in each surface treatment method were sealed with unfilled sealant and the other half were sealed with filled sealant. All of the teeth were thermocycled for 1200 cycles at $5^{\circ}C\;and\;55^{\circ}C$ and immersed in 5% methylene blue for 24 hours. Each tooth was sectioned bucco-lingually at mesial pit and distal pit and examined under a Measurescope. In the case of mechanical preparation, fissure penetration of sealant was significantly increased compared with the case of acid etching only(P < 0.05). The filled and unfilled sealant using mechanical preparation showed significantly decreased microleakage when compared with the unfilled sealant using acid etching only(P < 0.05). No differences were found in fissure penetration and microleakage between unfilled and filled sealant in both methods. Taken together, the results of this study suggest that mechanical preparation and filled sealant are recommended when placing pit and fissure sealant. However, further clinical studies should be performed in regard to microleakage.

• Elastomers and Composites
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• 제41권1호
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• pp.3-9
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• 2006

Optimal conditions for preparation of starch/PVA blends were investigated with the consideration of factors that may influence mechanical properties of the blends. Multiplex mixture optimal method as a statistical method were performed and then tensile strength, strain at break, Young's modulus and tear strength of films of the blends were measured to determine the optimal conditions for preparation. The mechanical properties needed for the degradable agricultural mulch were the target of this experiment. Results showed that although the strain at break was a little insufficient, the other properties were very close to the target. This means that the mechanical properties of the film from this blend as a whole are very compatible with those of the reference mulch.