• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.1 no.2
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• pp.144-153
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• 1991

This study was conducted to evaluate worker exposure to airborne asbestos fibers by industry, and to evaluate polarized-light microscopy for determining airborne asbestos fibers. A total of 11 plants including asbestos textile, brake-lining manufacturing, slate manufacturing, and automobile maintenance shops were investigated. Rsults of the study are summarized as follows. 1. Worker exposure levels to airborne asbestos fibers were the highest in asbestos textile industry, followed by brake-lining manufacturing, slate manufacturing, and automobile maintenance shops, in order. In asbestos textile industry, large variation of asbestos levels was found by plants. The worst plant indicated airborne fiber concentrations in excess of 10 fibers/cc, however, the best plant showed concentrations within 0.50 fibers/cc. 2. Characterization of airborne fibers by industry indicated that fibers from asbestos textile industry were the longest with the largest aspect ratio. Fibers from automobile maintenance shops were the shortest with the smallest aspect ratio. Based on characteristics of fibers and the highest levels of concentrations, it is concluded that workers in the asbestos textile industry are exposed to the highest risk of producing asbestosis, lung cancer, and mesothelioma. 3. Result s obtained using polarized-light microscopy were $43.7{\pm}12.3%$ of the results obtained using phase contrast microscopy. This may be resulted from the worse resolution of polarized-light microscopy than that of phase contrast microscopy. Based on the results, it is recommended that polarized-light microscopy be used for mainly bulk sample analyses and further study be performed to improve the method for determining airborne samples. However, polarized-light microscopy can be used for determining thick fibers.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.240.2-240.2
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.7-7
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• 2010

• Advances in materials Research
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• v.1 no.1
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• pp.75-81
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• 2012

In this work, the Co-doped ZnO rods were prepared by the hydrothermal method. The size of these rods can be changed from micro-size to nano-size by using different solutions during the preparation. The results of transmission electron microscopy (TEM) and selected area electron diffraction (SAED) showed that the as-prepared nano-sized Co-doped rods have single-crystal structure. The polarized Raman experiments were presented on an individual micro-sized Co-doped ZnO rod in the $X(YY)\vec{X}$, $X(ZY)\vec{X}$ and $X(ZZ)\vec{X}$ configurations, the results of polarized Raman indicated that these rods are crystallized and their growth direction is parallel to c-axis.

• Journal of the Optical Society of Korea
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• v.9 no.1
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• pp.32-35
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• 2005

In light microscopy, spatial resolution is limited by diffraction effect. Confocal microscopy has improved resolutions in both lateral and axial directions, but these are still limited by diffraction effect. Confocal self-interference microscopy (CSIM) uses interference between two perpendicularly polarized beams to enhance lateral resolution. In previous research, we proposed a calcite plate with its optic-axis perpendicular to the propagation angle and one of the boundary surfaces of the plate. This type of plate is not widely used to our knowledge. In this paper, we change the calcite plate to more common one, which is commercially available. This calcite plate has its optic axis in the plane of incidence. We analyze the characteristics of this calcite plate and numerically compare the performances of CSIM in previous research and CSIM with the commercial calcite plate. Numerical results show improved performance when using the commercial calcite plate

• YAKHAK HOEJI
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• v.38 no.3
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• pp.300-310
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• 1994

Physicochemical properties for the inclusion complex of chenodeoxycholic acid(CDCA) and it's $7{\beta}-hydroxy$ epimer ursodeoxycholic acid(UDCA) with ${\beta}-cyclodextrin({\beta}-CyD)$ were studied. The formation of the complex in the solid state were confimed by polarized microscopy and differential scanning calorimetry(DSC). Proton nuclear magnetic resonance$(^1H-NMR)$spectroscopy showed that CDCA and UDCA form an inclusion complex with ${\beta}-CyD$ in aqueous solution. The 1 : 1 stoichiometry of the complex was dextermined by the continuous variation method. From DSC and $^1H-NMR$ studies, there were not any differences between CDCA and UDCA. Complex of CDCA and UDCA showed increase in solubility and dissolution compared with CDCA and UDCA alone, respectively. Solubility pattern of UDCA complex was pH independent but, CDCA complex was like that of CDCA. Dissolution rate increased markedly in case of UDCA complex compared with CDCA complex, especially in acidic pH value.

• Current Applied Physics
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• v.18 no.11
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• pp.1185-1189
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• 2018

Thickness-dependent magnetic domain structure of ultrathin Co wedge films (0.3 nm-1.0 nm) sandwiched by Pt layers was investigated by scanning transmission x-ray microscopy (STXM) employing X-ray magnetic circular dichroism (XMCD), utilizing elliptically polarized soft x-rays and electromagnetic fields, with a spatial resolution of 50 nm. The magnetic domain images measured at the Co $L_3$ edge showed the evolution of the magnetic domain structures from maze-like form to the bubble-like form as the perpendicular magnetic field was applied. The asymmetric domain expansion of a 500 nm-scale bubble domain was also measured when the in-plane and perpendicular external magnetic field were applied simultaneously.

• Journal of the Korean Applied Science and Technology
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• v.14 no.3
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• pp.23-28
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• 1997

The phase diagram for the surfactant mixture system of N-dodecanocyl-N-methyl amido polyolcarboxyl alkyl ether(DGC)/N-dodecanocyl-N-alkyl glucamine(DG)/water was studied usingpolarized microscopy, differential scanning calorimetry(DSC) and rheological measurements respectively. Using polarized microscopy, the textures of liquid crystal phases obtained at various surfactantconcentrations were investigated as a function of surfactant concentration and temperature, and phasetransitions between anisotropic liquid crystal phases and isotropic liquid phase were examined usingDSC measurements. Viscoelastic properties of surfactant solutions determined between hexagonal andlamellar liquid crystal phase by rheological measurements were approximately consistent with the resultsobtained by polarized microscopy and DSC. In the study for the phase of DGC/DG(5:5 mol ratio)/water system. It could be found that the hexagonal liquid crystal phase appeared at 25${\sim}$60wt％ ofsurfactant, the cubic liquid crystal phase at 50${\sim}$65wt％ and the lamellar crystal phase at above 70wt％.

• Journal of Magnetics
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• v.7 no.1
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• pp.4-8
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• 2002

The magnetoresistance (MR) and the magnetization reversal of a lateral spin-injection device based on a spin-polarized field effect transistor (spin FET) have been investigated. The device consists of a two-dimensional electron gas (2DEG) system in an InAs single quantum well (SQW) and two ferromagnetic $(Ni_{80}Fe_{20})$ contacts: all injector (source) and a detector (drain). Spin-polarized electrons are injected from the first contact and, after propagating through the InAs SQW are collected by the second contact. By engineering the shape of the permalloy contacts, we were able to observe distinct switching fields $(H_c)$ from the injector and the collector by using scanning Kerr microscopy and MR measurements. Magneto-optic Kerr effect (MOKE) hysteresis loops demonstrate that there is a range of magnetic field (20~60 Oe), at room temperature, over which the magnetization in one contact is aligned antiparallel to that in the other. The MOKE results are consistent with the variation of the magnetoresistance in the spin-injection device.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1430-1431
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• 2006

We investigated the formation of 2-dimension hologram grating by means of selective etching characteristic and photo-expansion effect according to photo irradiation on amorphous As-Ge-Se-S thin film. By method of phase holography, we made the 2-dimensional hologram grating by each (S:P) and ($+45^{\circ}:-45^{\circ}$) polarized beam with DPSS laser(532nm) and He-Ne laser(632nm). A recording property was observed at each polarized beam through 2-dimensional hologram surface relief grating. Chalcogenide thin film was etched selectively by NaOH solution after the formation of 1-dimensional diffraction grating. And then etched sample was rotated 90 degree to fabricate 2 dimensional hologram grating. We found that it was observed the formation of 2-dimensional hologram grating by AFM(Atomic Force Microscopy).