• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.526-536
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• 2009

The aim of this vitro-study is to evaluate the effects of fluoride on remineralization of artificial dentine caries. 10 sound permanent premolars, which were extracted for orthodontic reason within 1 week. were used for this study. Artificial dentine caries was created by using a partially saturated buffer solution for 2 days with grounded thin specimens and fractured whole-body specimens. Remineralization solutions with three different fluoride concentration (1 ppm. 2 ppm and 4 ppm) were used on demineralized-specimens for 7 days. Polarizing microscope and scanning electron microscope were used for the evaluation of the mineral distribution profile and morphology of crystallites of hydroxyapatite. The results were as follows: 1. When treated with the fluoride solutions, the demineralized dentine specimens showed remineralization of the upper part and demineralization of the lower part of the lesion body simultaneously. 2. As the concentration of fluoride increased, the mineral precipitation in the caries dentine increased. The mineral precipitation mainly occurred in the surface layer in 1 and 2 ppm- specimens and in the whole lesion body in 4 ppm -specimens. 3. When treated with the fluoride solution, the hydroxyapatite crystals grew. This crystal growth was even observed in the lower part of the lesion body which had shown the loss of mineral.

• Journal of the Korean Wood Science and Technology
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• v.9 no.1
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• pp.1-12
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• 1981

The structure of spiral thickenings, particulary the appearance, arrangement and orientation of thickenings in compression wood of Torreya nucifera, were studied in detail by light and polarizing microscope, scanning and transmission electron microscope. The results obtained are as follows: (1) Using the inclined sections at an angle of 45 degrees to the fiber axis, it seems that we can not only observe the more accurate transverse view of the thickenings but also investigate the formation of their thickenings. (2) Generally 2-4 pieces of thickenings are projected to the cell lumen as nipple-like appearance in transverse section and are as frequent, well developed, forming pair and have the rope-like appearance in radial surface. (3) The secondary wall of early wood is composed of 3 layers (S1, S2, S3) and orientation of thickening appears S helix but that of late wood is of 2 layers (S1, S2) and that orientation shows Z helix. Above two regions are demaracted at several tracheid cells from the growth ring boundary. (4) Orientation of thickening seems to be a element showing the characteristics of compression wood in Torreya nucifera. (5) It believes that the thickenings of compression wood are integral part of the S3 in early wood tracheids and of the S2 in late wood and have the same orientations as the inner-most microfibrils in these layers. (6) Thickening and cavities seem to be not formed together in a secondary cell wall of same tracheids.

• Korean Journal of Optics and Photonics
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• v.20 no.6
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• pp.354-360
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• 2009

We have constructed and analyzed the performance of a simple fiber bundle multi-focal microscope. The microscope had a fiber bundle substituted for micro-lens array that is the core part of MMM(multi-focal multi-photon microscope). The MMM is a type of confocal microscope. To analyze the performance and characteristics of the fiber bundle multi-focal microscope, three types of samples were used: a standard grating, USAF 1951(7, 3), and 1951(7, 6). Using two polarizers and a polarizing beam splitter, we eliminated noise and got clear images. We obtained the FWHM of fiber spot images with the standard grating using two different magnifier lenses which were 63X and 20X, and found an image of the sample as a distribution of fiber spot images. For this case we used the low magnification lens, which gives denser distribution, so that we could get clearer images. In order to test the resolution of the fiber bundle multi-focal microscopic system, we used the USAF 1951 sample which has a smaller line interval than that of the standard grating. The FWHM of the line width of the image coincides well with the real line width of the USAF 1951 sample. We confirmed the performance of a fiber bundle multi-focal microscopic system which is relatively simple but has submicron resolution and is able to get 1600 images at the same time.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.1
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• pp.117-125
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• 1997

Ferroelastic $CsPbCl_3$ crystals were grown by the Czochralski method and Bridgman method. From XRD, DTA and the dielectric measurements, we investigated the structure and confirmed the phase transition temperatures of it. Using the polarizing microscope, we observed the ferroelastic domains and the temperature dependence of the domains. For the orientation states, we obtained the consistent result with the theoretical investigation by the crystallographical consideration. For Aizu species m3mF2/m(p) 12 orientation states are represented crystallographically.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1582-1584
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• 1997

We investigated the transcription of liquid crystal (LC) alignment method by using memory effect of nematic (N) LC on polyimide (PI) surface with side chain as for non-rubbing alignment techniques. That the monodomain alignment of aligned NLC is observed by polarizing microscope textures in the cells on PI surface with side chain, We obtained that the pretilt angle of NLC are generated about 3.7 degree on PI surface. We suggest that the LC alignment by using transcription aligngnment method is attributed to memory effect of NLC on PI surface.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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• pp.27-34
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• 2010

To obtain the basic information for the use of bamboo, the anatomical characteristics of moso bamboo shoots, and 20-day-old, 60-day-old, one-year-old, and two-year-old moso bamboo were observed by using polarizing microscope. The cross section showed that the bamboo shoots consists of the early stage of cell formation, atactostele, parenchyma, and bundle sheath was formed in 20-day-old moso bamboo, and all cells completely formed in 60-day-old moso bamboo. The tissues in one-year-old moso bamboo appeared to be completely matured. On the tangential surface, no atactostele was observed in the bamboo shoot, but metaxylem, parenchyma, and bundle sheath were found. atactostele and parenchyma appeared to be formed between 20 and 60 days. All tissues and cells were totally formed and the cell wall of parenchyma were completely matured after one year. The metaxylem in bamboo shoots was observed to have pits, which means that it could be the tissues first formed of all bamboo cells.

• The Research Journal of the Costume Culture
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• v.9 no.5
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• pp.759-769
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• 2001

The principal purpose of this study is focused on the fabrics used in Kaya period by investigating the imprinted fabrics on the remains of the old tomb of Dohang-ri and Jeesan-dong which were built around the late 4th century to the late 6th century. Most of the remains are plain weaved, however there is one remain that 4-end complex gauze with patterned, and the other is weaved with geometrical pattern which were plain weave with 2 · 1 twill and 3 · 1 twill. The imprinted fabrics that had twists had S twists only. Of all the fabrics that were examined, the most loose one had the density of 8 × 6/cm, the most fine fabric had the weft density of 91.8 strands/cm and the warp density cannot be counted. It is No. 416 of Doharg-ri tomb that has the highest ratio of density as 3.15. All the fabrics observed by SEM and Polarizing Microscope are hemp.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.238-243
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• 2000

The effect of the temperature, the fatigue and the test speed on DEN(double edged notch) specimen which was made by the pp-rubber composites during fracture was stuied. DEN specimen was made on PP-rubber composites through the injection molding. With increasing temperature the fracture strength is linearly decrease and the fracture energy is first increase by $0^{\circ}C$ and after that decrease. In the same temperature the fracture strength during increasing the notch radius is hardly increase. The fracture behaviour at low and high test speed is different entirely. At high test speed plastic region is small and fracture behaviour was seen to brittle fracture tendency. The deformation mechanism of polypropylene-rubber composites during fracture was studied by SEM fractography. A strong plastic deformation of the matrix material ahead of the notch/crack occured. The deformation seem to be enhanced by a thermal blunting of the notch/crack.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.34-37
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• 2002

Freestanding azobenzene-containing liquidcrystalline network (LCN) films. with macroscopic uniaxial molecular alignment were prepared by insitu photopolymerization. By polarizing microscopy, fiber-like structures aligned in one direction were observed. Furthermore, with a confocal laser scanning microscope (CLSM), it was confirmed that the fiber-like structures were formed even in the bulk of the LCNs. Upon UV light irradiation to cause trans-cis photoisomerization of the azobenzene molecules, the LCNfilms underwent a significant and anisotropic bending toward the irradiation direction of UV light. When the bent LCNfilms were exposed to Vis light, unbending of the LCN films immediately took place and the initial flat LCN films were restored. This bending and unbending behavior of the LCN films could be repeated just by changing the wavelength of the irradiation light. It was suggested that the bending was induced by an absorption gradient which produced a volume difference between the front surface area and the bulk of the network films.

• Economic and Environmental Geology
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• v.18 no.3
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• pp.289-299
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• 1985

Sedimentary petrology and depositional environments of the Sindong Group, consisting of in ascending order the Nagdong, Hasandong and Jinju Formations, in the Euiseong Subbasin are studied. For these, the Sindong sequence over 1,000m thick is measured at the scale of 1:200 and 36 thin sections of sandstones of the Hasandong Formation are studied under the polarizing microscope. In addition, published paleontologic data are incorporated in the sedimentologic interpretation. Most of the sandstones are classified as arkose. They are moderately sorted, near symmetrical to fine skewed and mesokurtic. Relationship between the textural parameters suggests a fluviatile environment of the Hasandong Formation. The Sindong fauna and flora also indicate non-marine depositional environments. Sedimentologic data of the measured sections show that the Sindong Group is made up of from the bottom an alluvial fan (lower part of the Nagdong Formation), a fluvial plain (upper part of the Nagdong Formation and the Hasandong Formation) and a fluvial/lacustrine (the Jinju Formation) deposits.