상아질과 치주조직에서 보이는 미세소관 구조의 편광현상

이상신,김종천,박시역,지영근,이승현,장민호,김연숙,이석근 대한구강악안면병리학회 2009 대한구강악안면병리학회지 Vol.33 No.3

The polarizing images of hard tissues including bone and cementum show characteristic features of different birefringence fortheir microstructures. Nevertheless, the clear mechanism of the amplified birefringence under polarizing microscope has not been well understood. We hypothesized that the unique polarized light could be accumulated in the microtubules due to the decreased refractory angle by the inside lower-density matrix, and then the accumulated light in the microtubules could be dispersed brightly. In order to elucidate the polarizing effect on the microtubules, the dentinal tubules in different conditions were observed, and compared with each other to explain their birefringence phenomena. In the decalcified sections of normal tooth, the dentinal tubules located near the pulp chamber showed strong birefringence, while the sclerosed dentinal tubules near the dentino-enamel junction did not show the birefringence. The birefringence was more conspicuous in the longitudinal sectionsof dentinal tubules than in the cross sections. In the decalcified sections of complex odontoma, which produced abnormal and immature dentinal tubules, the birefringence was not observed in the shrunken dentinal tubules filled with dense materials, while the peritubular matrix showed clear birefringence. The birefringence was also observed in the collagen fibers in the connective tissue, and continuously strong in the immature cemental materials containing precollagen fibers. However, the highly mineralized osteodentine did not show the birefringence. Taken together, these data suggest that the microtubules composed ofless-dense matrix than the background tissue, i.e., dentinal tubules, Haversian canals, etc., produce the amplified birefringence by the polarizing light according to the hypothesis of microtubule refraction.

Interplay of collagen and mast cells in periapical granulomas and periapical cysts: a comparative polarizing microscopic and immunohistochemical study

Bansal Deepty,Kamboj Mala,Narwal Anjali,Devi Anju,Marwah Nisha 대한치과보존학회 2022 Restorative Dentistry & Endodontics Vol.47 No.1

Objectives This pilot study aimed to establish the interrelationship between collagen and mast cells in periapical granulomas and periapical cysts. Materials and Methods An observational cross-sectional study was conducted on the paraffin-embedded tissue sections of 68 specimens (34 periapical granulomas and 34 periapical cysts). The specimens were stained with picrosirius to observe collagen fiber birefringence and anti-tryptase antibody to evaluate the mast cell count immunohistochemically. The mean number and birefringence of collagen fibers, as well as the mean number of mast cells (total, granulated, and degranulated), and the mean inflammatory cell density were calculated. The data obtained were analyzed using the Kruskal Wallis test, Mann Whitney U test, and Spearman correlation test (p < 0.05). Results The mean number of thick collagen fibers was higher in periapical cysts, while that of thin fibers was higher in granulomas (p = 0.00). Cysts emitted orange-yellow to red birefringence, whereas periapical granulomas had predominantly green fibers (p = 0.00). The mean inflammatory cell density was comparable in all groups (p = 0.129). The number of total, degranulated, and granulated mast cells exhibited significant results (p = 0.00) in both groups. Thick cyst fibers showed significant inverse correlations with inflammation and degranulated mast cells (p = 0.041, 0.04 respectively). Conclusions Mast cells and inflammatory cells influenced the nature of collagen fiber formation and its birefringence. This finding may assist in the prediction of the nature, pathogenesis, and biological behavior of periapical lesions. Objectives This pilot study aimed to establish the interrelationship between collagen and mast cells in periapical granulomas and periapical cysts. Materials and Methods An observational cross-sectional study was conducted on the paraffin-embedded tissue sections of 68 specimens (34 periapical granulomas and 34 periapical cysts). The specimens were stained with picrosirius to observe collagen fiber birefringence and anti-tryptase antibody to evaluate the mast cell count immunohistochemically. The mean number and birefringence of collagen fibers, as well as the mean number of mast cells (total, granulated, and degranulated), and the mean inflammatory cell density were calculated. The data obtained were analyzed using the Kruskal Wallis test, Mann Whitney U test, and Spearman correlation test (p < 0.05). Results The mean number of thick collagen fibers was higher in periapical cysts, while that of thin fibers was higher in granulomas (p = 0.00). Cysts emitted orange-yellow to red birefringence, whereas periapical granulomas had predominantly green fibers (p = 0.00). The mean inflammatory cell density was comparable in all groups (p = 0.129). The number of total, degranulated, and granulated mast cells exhibited significant results (p = 0.00) in both groups. Thick cyst fibers showed significant inverse correlations with inflammation and degranulated mast cells (p = 0.041, 0.04 respectively). Conclusions Mast cells and inflammatory cells influenced the nature of collagen fiber formation and its birefringence. This finding may assist in the prediction of the nature, pathogenesis, and biological behavior of periapical lesions.

사출 공정조건 개선을 통한 복굴절 저감현상에 대한 연구

이경범(Kyong-Bom Lee),윤경환(Kyung-Hwan Yoon),이성희(Sung-Hee Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

Residual stress and birefringence which developed in injection molded parts affect dimensional the accuracy and mechanical property of final products. As for the quality of product, process conditions must be considered to reduce the residual stress and birefringence. In this study injection molded optical plastic products were prepared with under fixed process conditions, such as melt temperature, mold temperature, packing pressure. Birefringence of the optical plastic product was measured by polariscope to evaluate the influence of the process conditions. The distribution and magnitude of birefringence were measured by equivalent distance from the gate of the part. It was shown that birefringence was decreased from gate position to end point of the part for each process conditions.

비틀림 방법을 통한 단일모드 광섬유의 미세 복굴절도의 측정

최태일,정해양 경희대학교 레이저공학연구소 2001 레이저공학 Vol.12 No.-

We describe a twist method for measuring ultralow birefingence(i.e. Δn□10-6~10-8) in single mode optical fibers. In twisted single-mode optical fibers the output state of polarization of light is affected by an elastooptically induced optical activity and by modification of any linear birefringence. The measuring procedure involves measurement of the light intensity only and does not require an analysis of the light-polarization state. Experimental results for commercial single mode fibers with Δn□2×10-6 are presented.

Prediction of birefringence distribution for optical glass lens

Na, J.W.,Rhim, S.H.,Oh, S.I. Elsevier 2007 Journal of materials processing technology Vol.187 No.-

<P><B>Abstract</B></P><P>Based on the viscoelastic theory, simulations were carried out on glass-lens forming processes. In addition, the birefringence distribution was calculated by stress-optic relation. First, to verify this viscoelastic simulation, FEM analysis was performed with the same material properties and process conditions used in the Bruckner's experiment. The result of the analysis was compared with Nadai's and Bruckner's results. The simulation results were in good agreement with the deformation and birefringence distribution in the experimental results. Finally, the FEM simulation technique was applied to actual LD-lens. The simulation was performed for each different cooling rate and the results were compared to each other in terms of birefringence. To investigate the effect of initial preform shape to optical property, a simulation was performed by using the new-proposed-shape-preform and the results were compared to the present shape in terms of birefringence.</P>

투명 사출품에서 성형조건에 따른 복굴절 및 잔류응력의 분석

우정우(Jeong-Woo Woo),홍진수(Jin-Su Hong),김현구(Hyun-Ku Kim),류민영(Min-Young Lyu) 한국고분자학회 2016 폴리머 Vol.40 No.2

사출성형품에 형성된 잔류응력은 시간이 지남에 따라 제품에 변형이나 휘어짐을 일으키고 투명한 제품의 경우 복굴절을 일으킨다. 사출성형 중에 형성되는 잔류응력은 성형온도, 금형온도, 냉각조건, 보압조건과 같은 사출성형 조건에 의해 다르게 나타난다. 잔류응력의 측정방법 중 광탄성을 이용한 측정법은 다른 방법들에 비해 간편하고 쉽게 측정할 수 있는데 투명한 제품에만 적용이 가능한 방법이다. 복굴절 분포와 잔류응력의 크기를 PC, PS, 그리고 PMMA를 이용한 사출성형 시편을 통해 연구하였다. 그리고 컴퓨터 시뮬레이션을 통해 복굴절 패턴을 모사하고 실험결과와 비교하였다. PS 시편은 가장 높은 복굴절을 나타냈고 PMMA는 가장 낮은 복굴절을 보였다. 제품의 잔류응력은 게이트 근처에서 가장 컸고 게이트에서 멀수록 작았다. 사출성형에서 냉각시간이 길고, 사출온도가 높고, 보압시간이 길수록 제품 내에 잔류응력은 줄어들었다. Residual stresses are developed during injection molding process and these cause a warpage and invoke a birefringence in a molded article. The levels of residual stresses are dependent of molding conditions, such as melt temperature, mold temperature, cooling condition, and packing condition. Among the residual stress measurement methods, the photoelasticity method is simple and convenience to measure compared with other methods. However this method can be utilized only for a transparent product. Birefringence and residual stress have been observed in injection molded polycarbonate (PC), polystyrene (PS), and polymethylmethacrylate (PMMA) specimens according to injection molding conditions. Computer simulation has been performed and compared with experimental observation of birefringence. PS specimen showed the highest birefringence whereas PMMA showed the lowest birefringence among them. Locations close to the gate showed higher residual stress than locations far from the gate. Long cooling time, high injection temperature, and long packing time reduced residual stress.

두께에 따른 WTe2의 복굴절 특성 관찰

김진형,신치원,김정길 한국물리학회 2024 새물리 Vol.74 No.2

Weyl semimetal 중 하나인 WTe2는 두께에 따라 금속 특성과 반도체 특성을 갖는 물질이다. 그중에서도 Td-phase WTe2는 대칭성이 깨진 결정구조에 의해 야기하는 anomalous Hall effect로 인하여, 물질에 전류가 흐를 때 표면에 수직한 방향으로 자기장 특성이 생기는 위상 물질이다. 이러한 특성은 결정의 대칭성과 전류가 이루는 각도에 의존적이다. 예를 들면 WTe2에 선형편광 빛이 입사하는 경우에 빛의 편광방향으로의 전기장이 WTe2 표면에 형성되고, 따라서 WTe2 표면에 자유전자의 진동에 의한 전류가 발생한다. 빛의 편광 방향에 따라 표면에 수직한 자화의 크기가 달라지기 때문에 굴절률도 달라져 복굴절 특성이 나타난다. 본 연구에서는 WTe2의 복굴절 특성을 관찰하기 위해 선형 편광된 빛을 WTe2 표면에 입사하고, 결정방향을 회전하며 반사광을 측정하였다. 특히 두꺼운 벌크구조와 얇은 박막구조의 두가지 WTe2를 준비하여 반사광을 측정하여 두께에 의존적인 WTe2의 복굴절 특성을 확인하였다. 그 결과 얇은 박막구조에서 더 강한 복굴절 특성을 관찰할 수 있었다. 이러한 현상은 층수가 많아질 수록 저항이 커지는 WTe2 의 특성에 기인한다고 볼 수 있다. Td-phase WTe2 is a phase material with a magnetic characteristic due to the anomalous Hall effect. When linearly polarized light is illuminated on WTe2, an electric field in the polarization direction is formed on the surface of WTe2, and thus an electrical current is generated by oscillation of free electrons. Since the magnitude of the magnetization perpendicular to the surface varies depending on the polarization direction of light, the refractive index also changes, resulting in birefringence. In this study, in order to observe the birefringence characteristics of WTe2, linearly polarized light was incident on the WTe2 surface, and the reflected light was measured while rotating the crystal direction. Moreover, two types of WTe2, a thick bulk structure and a thin film structure, were prepared and reflected light was measured to confirm the thickness-dependent birefringence characteristics of WTe2. As a result, stronger birefringence characteristic was observed in the thin film structure. This phenomenon can be attributed to the characteristic of WTe2, in which resistance increases as the number of layers increases.

Fiber-Type Phase Retarder Based on Photo-Induced Birefringence of a Standard Single-Mode Fiber and Its Feasibility of Realizing Polarization-State Converters

이병하,김명진 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.2

We present a fiber-type phase retarder that is implemented by using a short segment of a single-mode ber. To induce the phase retardation, we utilize the photo-induced birefringence. Though the photo-induced birefringence was small, it was enough to realize quarter-wave retardation. In our works, by cascading two fiber-type quarter-wave segments in series and rotating one and/or both of them, we could conrm the potential as a polarizationstate converter. All birefringence segments were encapsulated in metal tubes and were terminated with fiber ferrules so that we could simultaneously rotate the birefringence axis and increase the connectivity to other devices. The theoretical results are given and are compared with the experimental ones.

단일 모드 광섬유의 복굴절이 편광상이 배치구조 기반 고차 광섬유 빗살 필터의 출력 스펙트럼에 미치는 영향에 대한 고찰

김영호(Young-Ho Kim),이용욱(Yong-Wook Lee) 한국조명·전기설비학회 2012 조명·전기설비학회논문지 Vol.26 No.6

In this paper, we investigated possible optical parameters causing deviation of experimentally observed output spectra from theoretically predicted results in a high-order fiber comb filter based on a polarization-diversity loop configuration. They include wavelength dependency of half-wave plates (HWPs) inserted in the filter for wavelength switching and the modal birefringence of single-mode fibers (SMFs) with which optical components comprising the filter are connected. In order to consider the effect of the modal birefringence of the SMF on a filter performance, it is modeled as a low birefringence fiber with an arbitrary orientation angle and birefringence. It is found from the simulation results that the modal birefringence of SMFs strongly affects the spectral characteristics of the filter and decreases the extinction ratio of the filter, compared with the wavelength dependency of HWPs. In particular, it is also confirmed that the spectral deviation and asymmetric distortions of side-lobes in narrow band transmission spectra result mainly from the modal birefringence of SMFs.

Birefringence 기법을 이용한 볼트의 응력측정에 관한 연구

하완(Wan Ha),김노유(Nohyu Kim) 대한기계학회 2001 대한기계학회 춘추학술대회 Vol.2001 No.8

Bolts widely used in machine parts and assemblies are preloaded to prevent the parts from seperating and to maintain the strength of the assemblies. Conventional technique for measurement of this axial stress applied to bolts is torque meter, but it has two disadvantages. The first one is its inherent inaccuracy. The second is that the stress cannot be determined after assembly without twisting bolts. The most promising technique for measurement of the axial stress is acousto-elasticity. In this study, a new acousto-elasticity technique based on Birefringence principle is proposed and tested to measure the axial stress in bolts which uses two wave, longitudinal and shear waves instead two vertically polarized. From experimental results, the wave velocity difference between longitudinal wave and shear wave is shown to be linearly related to the applied stress and be able to be used effectively to monitor the axial stress in bolts.