• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.137-146
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• 1995

Twenty(20) large commercial buildings located in Seoul with friable sprayed-on surface insulation material on ceilings were investigated for asbestos content in bulk material by polarized light microscopy and for airborne fiber concentrations in buildings by phase contrast microscopy. In addition, such building-related variables as building age, numbers of traffic, airflow, surface conditions of the ceiling, temperature, and humidity were studied for any correlation with airborne fiber concentrations. The results were as follows: 1. Chrysotile asbestos was found in two bulk samples with 3-5% content and with <1%in one sample out of total 20 bulk samples collected. Glass fiber and mineral wool were the two major constituents of the bulk samples. 2. The ceiling surfaces were very friable in 16 buildings and were relatively hard in 4 buildings. The friability of the surface material was dependent upon the type and the amount of binder that had been mixed with the sprayed-on surface material. 3. Airborne fiber concentrations were log-normally distributed and the geometric mean(geometric standard deviation) fiber concentrations in the underground parking lots, inside buildings, and outdoor ambient air were 0.0063(1.97)f/cc, 0.0068(2.29)f/cc, and 0.0033(2.36)f/cc, respectively. 4. No significant relationship of airborne fiber concentrations and all building-related variables studied except humidity was found. The results of this study suggest that the sprayed-on surface insulation material found in some commercial buildings may possibly be contaminated with asbestos. Since most of the ceiling surfaces surveyed were very friable and poorly maintained and the airborne fiber concentrations were relatively high, there is a possibility of asbestos fiber contamination in these buildings, particularly at those buildings with asbestos-contaminated surface material. Since poorly maintained surface conditions were thought to be a source of high airborne fiber concentrations, there is a urgent need of a systematic operation and maintenance program. Further study of non-occupational asbestos exposure in general population utilizing advanced analytical technique such as transmission electron microscopy is highly recommended.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.718-726
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• 2007

There are many varieties of asbestos: chrysotile, crocidolite, amosite, tremolite, actinolite, and anthophylite. These are widely used in construction materials, brake lining, textile, and so on. Even though non-asbestos fibers such as glassfiber and rockwool have manufactured because asbestos causes asbestosis, lung cancer, mesothelioma, etc., some bad effects of non-asbestos have been also reported. PCM (phase contrast microscopy) and PLM (polarized light microscopy) have been used to qualitatively analyze asbestoses. These techniques have serious drawbacks when identifying and separating various asbestoses. Recently scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX) has been known as an useful tool to analyze airborne particle since it provides physical and chemical information simultaneously. The purpose of the study was to classify both asbestos and non-asbestos fibers and finally to develop their source profiles by using the SEM/EDX. The source profiles characterized by 6 different types of asbestos fibers and 2 types of non-asbestos fibers had been developed by analyzing a total of 380 fibers. Analytical parameters used in this study were length, width, aspect ratio, and shape as physical information, and Na, Mg, Al, Si, K, Ca, Cr, Mn, Fe, and Cu as chemical information. All the parameters were intensively reviewed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.2
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• pp.165-175
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• 1996

Fourteen(14) large commercial buildings located in Seoul with friable sprayed-on surface insulation material on ceiling were investigated for fiber types in bulk material and for airborne fiber concentrations in buildings by transmission electron microscopy (TEM) in order to compare the results with those by polarized light microscopy (PLM) and phase contrast microscopy (PCM). The results were as follows: 1. Chrysotile asbestos was found in one bulk sample out of total 14 bulk samples collected. Glass fiber and mineral wool were the two major constituents of the bulk samples. 2. The Na-Mg-Si-Ca-Fe-Al ratios of the EDX spectra which were normalized with the Si peak were 0-1.0-10-8.3-4.0-4.0 in mineral wool and 0-5-10-21-0-0 in chrysotile asbestos, respectively. 3. Airborne fiber concentrations were log-normalcy distributed and the geometric mean (geometric standard deviation) fiber concentrations by TEM in the underground parking lots and inside buildings were 0.0048 f/cc(1.93) and 0.0040 f/cc(2.27), respectively with no statistical difference. In the outdoor ambient air, statistically significantly lower concentration of 0.0018 f/cc(2.04) was measured. 4. The TEM/PCM ratios of airborne fiber concentrations ranged 0.5 - 2.0 for 80 % of airborne samples analyzed, end the regression equation between TEM and PCM was PCM=-0.2724+1.1355(TEM) with the coefficient of determination $R^2=0.52$. The results of this study confirmed that the sprayed-on surface insulation material found in some commercial buildings may possibly be contaminated with asbestos fiber. Since statistically significant relationship of fiber concentrations measured by PCM and TEM inside buildings and ambient air was found, previous results by PCM in ambient air could be used to estimate the ambient fiber concentrations in knowing the ratio of TEM/PCM.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.314-315
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• 2003

석면은 자연적으로 발생되는 광물로 1887년 캐나다의 케베크 지방에서 채굴이 시작되어 흡음, 단열, 내부식성, 내약품성이 뛰어나고 값이 싸자는 이점 때문에 90%이상이 건축재료로 사용되었다. 석면은 장기간 노출될 경우 대략 15년에서 30년의 잠복기를 거쳐 석면폐증, 폐암 악성 중피종을 등을 유발하며 단 한번 진단되면 아직 이렇다할 치료방법이 없다. 대체적으로 석면폐의 경우 질병의 발생과 석면 섬유 사이에는 양-반응관계를 보이며(Beckla ke et al., 1980) 악성중피종과 폐암의 경우는 화학적 성질과 함께 섬유의 굵기, 길이, 모양 등의 물리적 성질이 질병의 발생과 밀접한 관계가 있는 것으로 보고되고 있다(Lippmann, 1988). (중략)

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.51-51
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• 2012

Cellulose is extremely difficult to dissolve cellulose in water and most common organic solvents due to their stiff molecular structure, close chain packing and intermolecular hydrogen bonds. Recently, cellulose solutions using ionic liquids (ILs) as a green solvent have been known to form cholesteric liquid crystalline phase at high cellulose concentration. In this study, the phase transition and rheological behaviors of concentrated cellulose/[AMIM]Cl solution were investigated using polarized optical microscopy and rheometry. Studies were conducted to characterize the influence of cellulose concentration on the phase transition of the cellulose solution and the mechanical properties of the regenerated fibers spun from the anisotropic cellulose/[AMIM]Cl solutions.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.51-60
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• 1996

A new one series of chiral schiff's base containing benzylidene aniline moieties was synthesized and characterized by IR, $^1H$ NMR. elementary analysis, and polarized optical microscopy(POM). The yield of these synthetic compounds was in the range of $62{\sim}67^{\circ}C$. The results showed that most of the synthetic compounds were monotropic liquid crystal and exhibited chiral smectic C($Sc^{\ast}$) liquid crystal phases, and the range of phase transition temperature was to $71.4^{\circ}C$ from $45.0^{\circ}C$.

• Macromolecular Research
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• v.14 no.2
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• pp.205-208
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• 2006

A polymeric film of a biodegradable poly(1,5-dioxepan-2-one) (PDXO) was formed on a gold surface by a combination of the formation of self-assembled monolayers (SAMs) presenting hydroxyl groups and the surface-initiated, ring-opening polymerization (SI-ROP) of 1,5-dioxepan-2-one (DXO). The SI-ROP of DXO was achieved by heating a mixture of $Sn(Oct)_2$, DXO, and the SAM-coated substrate in anhydrous toluene at $55^{\circ}C$. The resulting PDXO film was quite uniform. The PDXO film was characterized by polarized infrared external reflectance spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, atomic force microscopy, ellipsometry, and contact angle goniometry.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.2
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• pp.147-151
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• 1998

Primary localized laryngeal amyloidosis is an uncommon disorder of unknown cause that occurs in the absence of systemic amyloidosis or associated disease. There is a risk of either missing concomitant systemic amyloidosis or exhaustively investigating for this when it is not present through failure to appreciate the nature of the disease. We present 2 cases of primary localized laryngeal amyloidosis in supraglottic region. Biopsy of the mass of patients revealed findings consistent with amyloidosis, which were Congo red reaction with a apple green birefringence in polarized light fluorescence microscopy. An extensive workup for systemic amyloidosis was negative. All of two cases were treated by vaporization via $CO_2$ LASER using "Swiftlase Flshscan" for creating a wide, shallow char-free treatment site by precisely controlling ablation depth without causing residual thermal damage to tissue. The postoperative recovery of all cases was uneventful with good vocal quality and no aspiration. At the present time, the patients have no evidence of disease, recurrence and complication.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.158-159
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• 2000

광원의 근처에만 존재하는 근접장(Near-field)이 먼장(Far-field)과는 매우 다른 특성을 보인다는 것은 널리 알려진 사실이다. 일반적으로 먼장은 횡파(transverse wave)이며 광원에서 멀어질수록 1/r의 함수로 그 세기가 감소하는데 반하여, 근접장은 시간의존항을 제외하고는 정적인 분포를 보이고(static), 종파(logitudinal wave)성분이 오히려 크며 광원의 미세구조에 직접 관련되어 있다. 이러한 근접장이 근접장 주사 광학현미경(Near-field Scanning Optical Microscopy)의 발전으로 인해 실험적으로 연구되기 시작하면서 여러 가지 예기치 못한 현상들이 발견되고 있다. 그중 하나로서, 원편광된 빛(Circularly polarized light)을 내는 광원의 근접장을 측정한 실험에서 광원에 접근할수록 원편광이 사라지는 현상이 실험적으로 보고된바 있다.$^{(1)}$ 본 발표에서는 Bethe의 모델과 다중극 장(Multipole field)의 근접장을 분석하여 고전전자기론 내에서 근접장의 각 운동량에 대해 논의한다. (중략)

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.933-935
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• 2002

In this paper, new non-chiral molecules with semi-fluorinated alkyl chains were synthesized varying the structure of central bent core unit. Their mesomorphic properties were investigated by DSC and polarized microscopy. The compound with 1,3-dihydroxy phenylene unit could form an enantiomeric smectic phase, but the remaining compounds with bent-core mesogenic unit were not liquid crystalline. In this presentation, their x-ray measurement and electro-optical property will be also described.