• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.10a
• /
• pp.1-9
• /
• 1996

The aggregates with the different mineralogical features are studied how to affect the basic physical properties of concretes according to the changes of the chemical composition, mineralogical composition, crystal size, the standard qualities in the aggregates in using chemical analysis, X.R.D. DT-TGA, polarized light microscope, streoscopic microscope, standard test method of aggregates & concretes. At this studies, we found that aggregates without the seathered mineral such as muscovite & kaolin mineral etc, is superior to the others with the weathered mineral, even if it's standard qualities are inferiored to the other's. For examples, in manufacturing high strength concretes. The strength of concretes used aggregates without weathered mineral are improved about 15% than the other's and also. For general mixture to manufacture remicon, more about 10-20% than the other's strength and workability.

• Fibers and Polymers
• /
• v.5 no.4
• /
• pp.259-263
• /
• 2004

Rubber-modified epoxy resins have been employed as adhesive and matrix materials for glass and corbon-fiber composites. The behavior of fracture around a crack tip for rubber-modified epoxy resin is investigated through the acoustic emission (AE) analysis of compact tension specimens. Damage zone and rubber particles distributed around a crack tip were observed by a polarized optical microscope and an atomic force microscope (AFM). The damage zone in front of pre-crack tip in rubber-modified specimen $(15wt\%\; rubber)$ began to form at about $13\%$ level of the fracture load and grew in size until $57\%$ load level. After that, the crack propagated in a stick-slip manner. Based on time-frequency analysis of AE signals and microscopic observation of damage zone, it was thought that AE signals with frequency bands of 0.15-0.20 MHz and 0.20­0.30 MHz were generated from cavitation in the damage zone and crack propagation, respectively.

• Proceedings of the KACD Conference
• /
• 2003.11a
• /
• pp.615-615
• /
• 2003

I. Objectives This study was performed to get some information about micromorphology of subsurface lesion of root caries by observing autofluorescence using confocal laser scanning microscope(CLSM) with minimum sample preparation. II. Materials and Methods Half-cut and 1 mm thick sample of human teeth were prepared to produce artificial root carious lesions. Incipient subsurface lesions were produced under optimal pH and saturity. The lesions were observed by polarized microscopy, CLSM, and back-scattered electron microscope(BSE). Calcium and phosphorus concentrations of the lesions were analyzed by line EDAX. (omitted)

• Journal of the Korean Applied Science and Technology
• /
• v.25 no.2
• /
• pp.205-210
• /
• 2008

The transformation of the liquid crystal complex made by binding of anionic surfactant, sodium dodecyl sulfate (SDS), into high charge density cationic polymer, the homopolymer of diallyldimethylammonium chloride (PDADMAC) was induced by adding of nonionic surfactants and investigated by means of microscopy and FE.SEM. Among nonionic surfactants in this experiments polyethylene glycol (3 mol) ether of lauryl alcohol (laureth-3) made variation in the complex. The laureth-3 transformed the complex into spherulite vesicle with the size of ca.$100{\mu}m$. This change increased the viscosity and the turbidity of the solution phase separated originally. Microscope showed that they are spherulite particles and polarized microscope suggested they are multi.lamellar liquid crystals. FE-SEM also proved that explicitly.

• Fibers and Polymers
• /
• v.5 no.3
• /
• pp.198-203
• /
• 2004

Composite films were prepared by casting the solution of polyacrylonitrile (PAN) and single wall nanotube (SWNT) in DMF subsequent to sonication. The SWNTs in the films are well dispersed as ropes with 20-30 nm thickness. Moreover, AFM surface image of the composite film displays an interwoven fibrous structure of nanotubes which may give rise to conductive passways and lead to high conductivity. The polarized Raman spectroscopy is an ideal characterization technique for identification and the orientation study of SWNT. The well-defined G-peak intensity at 1580 $cm^{-1}$shows a dependency on the draw ratio under cross-Nicol. The degree of nanotube orientation in the drawn film was measurable from the sine curve obtained by rotating the drawn film on the plane of cross-Nicol of polarized Raman microscope. The threshold loading of SWNT for electrical conductivity in PAN is found to be lower than 1 wt% in the composite film. The electrical conductivity of the SWNT/PAN composite film decreased with increasing of draw ratio due to the collapse of the interwoven fibrous network of the nanotubes with uniaxial orientation.

• Journal of Periodontal and Implant Science
• /
• v.38 no.3
• /
• pp.467-474
• /
• 2008

Purpose: To evaluate RBM surface implant which has its good character like that good initial stability, early bone formation. Material and Methods: In this study fixures have divided in 2 group: Machined(Group I), RBM(Group II). Total 10 fixtures were implanted on rabbit which sacrificed on week 2 and week 4 for the histological specimens. By these specimens polarized microscopic view, micro CT view, ISQ value were measured, compared and analysed by each group to figure out the evidence that clinical use of RBM implant. Result: ISQ value had no significance differences between 2 groups, However in each group 4, 8 weeks had higher ISQ value than 2 weeks. In polarized microscope, calcification level was following: Group II, Group I. In micro CT, formation of cancellous bone level was following: Group II, Group I. Conclusion: RBM implant was the most excellent on the early bone formation and good initial stability.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.38 no.4
• /
• pp.317-326
• /
• 2011

QLF-D system composed with DSLR(digital single-lens reflex) camera, and the images of natural enamel caries and artificial caries was developed from 2 days to 14 days captured by QLF-D system. The correlation between lesion depth of the polarized microscope and luminosity ratio of QLF-D image was analyzed and the results were summarized as follows: 1. The Pearson correlation value between the lesion depth of polarized microscope images and luminosity ratio of QLF-D images was 0.969(p<0.01). 2. From Regression analysis of lesion depth from polarized image by demineralized period, the equation was y = 8.67x - 1.16(p<0.05). 3. From Regression analysis of luminosity ratio from QLF-D image by demineralized period, the equation was y = 3.53x + 6.42(p<0.05). From the results, QLF-D system can detect the enamel caries at the very early stage and can monitor the progression of demineralization and remineralization. For the convenient use of QLF-D system in the laboratory, the image analysing software was needed to analyze of interest site of enamel caries lesion.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.35 no.4
• /
• pp.684-691
• /
• 2008

Many operations have been carried out using the fluoride ion to prevent and reverse dental caries. It certainly encourages remineralization and also prevents dental caries. However, the remineralization developed by these means is superficial only leaving lower levels of demineralized lesion with a degree of porosity and incomplete mineralization. We must consider its toxic effects when it is ingested for overdose. The CPP-ACP paste is able to remineralize the incipient lesion and has no harmful effects when it is ingested, because it was made form casein which is from the protein of milk. The purpose of this article is to compare the remineralization effects between APF gel and the CPP-ACP paste. we applicated the APF gel and CPP-ACP paste on the artificial enamel carious lesion. After 14 days, we measured the surface microhardness and observed the remineralized lesion under polarized light microscope. The results were as follows : 1. The surface microhardness of group III was the highest, followed by group II, and I(p<0.05). 2. The surface microhardness of group III was significantly higher than those of group I, and II(p<0.05). 3. We could observe thin and irregular remineralization layer of group II, and regular and moderate remineralization layer of group III under polirized light microscope.

• Textile Coloration and Finishing
• /
• v.26 no.4
• /
• pp.305-310
• /
• 2014

In this study, we presented a newly synthesized pyrene-naphthalene diimide(NDI)-pyrene triad. The optical and structural properties were examined using various characterization techniques. A donor-acceptor-donor triad molecule exhibited a strong charge transfer, though there existed neither intramolecular nor intermolecular hydrogen bonding sites, due to the formation of preferential complementary complex between pyrene and NDI. Powder XRD measurement revealed a sharp and distinctive X-ray patterns, indicating the presence of microcrystalline-like structure. POM images showed anisotropic fingerprint texture similar to that of cholesteric phase, and SEM images showed numerous columnar structures with length of 1 to $10{\mu}m$. Above observation clearly demonstrated that ${\pi}$-complementary NDI-pyrene interactions in the traid was strong enough to form columnar aggregates in the long range.

• Journal of the Optical Society of Korea
• /
• v.18 no.5
• /
• pp.598-604
• /
• 2014

A polarization fluorescence correlation spectroscopy system based on a confocal microscope was built to study the rotational and translational diffusion of CdSe/CdS quantum rods (Q-rods), with the same and different polarization states between the polarizer and the analyzer (i.e. the XXX and XYY states). The rotational diffusion amplitude showed the dependences on polarization of $0.75{\pm}0.05$ in the XXX state and $0.26{\pm}0.03$ in the XYY state, when the translational diffusion amplitude was 1. The diffusion coefficients of the Q-rods were found based on their translational and rotational diffusion times in the two polarization states, in solutions with viscosity ranging from 0.9 to 6.9 cP. The translational and rotational diffusion coefficients ranged from $1.5{\times}10^{-11}$ to $2.6{\times}10^{-12}m^2s^{-1}$ and from $2.9{\times}10^5$ to $5.6{\times}10^4s^{-1}$, respectively.