• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.9
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• pp.801-808
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• 1991

Volume holographic interconnection scheme for photonic sitching and optical neural network has been presented. Theoretical formulation for photorefative space-change fields generated by the illumination of multiple noncollinear plane light interferenc pattens was achieved by substituting the complex Fourier series of the space-chage field and freecarrier density into Kukhtarev's nonlinear diffeential equations.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.31-35
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• 2003

Several poly(6-dialkylamino-1,3,5-triazine-2,4-dithioxylene) derivatives were synthesized by the polycondensation of 6-dialkylamino-1,3,5-triazine-2.4-dithiol with m- and p-dibromide xylene in a cetyltrimethyl ammonium bromide at $70^{\circ}C$ for 24h. The synthesized derivatives had refractive Indexes of 1.580~1.697 and had molar absorptivity of 97~196.6. In these derivatives, we knew that they are a polymer having high refraction indexes without double refraction because they contain triazine rings and sulfur atoms with high electron density.

• Polymer(Korea)
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• v.33 no.5
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• pp.413-419
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• 2009

As the refractive index of the prism layer becomes higher, the optical performance of the prism sheet gets better and the efficiency of the LCD backlight unit is improved. In order to increase the refractive index of the prism layer, the ultraviolet curing type resins were prepared by mixing high refractive index materials containing aromatic groups and the multi-functional reactive diluents. By using 9,9-bis [4-(2-acryloyloxyethoxy)phenyl] fluorene, the refractive index of the prism layer was increased up to 1.58 and the brightness of the backlight unit was improved. Since the light source used in the backlight unit caused the yellowing in the prism sheet and deteriorated the brightness accordingly, the hindered amine light stabilizer was used to improve the yellowing resistance successfully.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.131-137
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• 2004

The aim of this paper is to find the weather conditions which make the abnormal propagation of a radar bear In order to analyze the weather conditions which cause superrefraction or ducting, the meteorological data of the west sea and the south sea of Korea are classified which are observed during three years from 2000. Atmospheric indexes of refraction with increasing altitude are calculated and the rate of variation of temperature and hmidity at the altitude where the index is very low are observed. It is found that unwanted radar echoes by anomalous propagation are showed up only when the atmospheric indexes of refraction at a altitude is less than -150/km and the reverse layer of temperature appears with a sudden drop of humidity at the altitude.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.12
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• pp.581-586
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• 2017

This paper proposes a GPU based water surface animation and rendering technique for interactive applications such as games. On the water surface, a lot of physical phenomenon occurs including reflection and refraction depending on the viewing direction. When we represent the water surface, not only showing them in real time, but also make them adjusted automatically. In our implementation, we are able to capture the reflection and refraction through render-to-texture technique and then modify the texture coordinates for applying separate DU/DV map. Also, we make the amount of ratio between reflection and refraction change automatically based on Fresnel formula. All proposed method are implemented using OpenGL 3D graphics API.

• Journal of the Korean Ceramic Society
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• v.41 no.11
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• pp.826-833
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• 2004

In this study, photosensitivity dynamics in SiO$_2$ glass with the composition similar to that of silica Planar Lightwave Circuit (PLC) devices was investigated as a fundamental study prior to the device fabrication. Silica bulk glasses with similar composition to the core layer of PLC devices were prepared with variable composition of B$_2$O$_3$. The photosensitivity in boron and germanium co-doped SiO$_2$ glass yields refractive index change $\Delta$n as high as 10$\^$-3/. However such index modulation disappeared after annealing. From the result of annealing experiment and W absorption / Raman spectra, we conclude the compaction model is applicable to our glass system.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.49-54
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• 2013

Japan and South Korea since 2004 until now for the broadcast channel interference, by measuring the ongoing conflict are expected to prepare for the future, but Korea's preparation are not enough. In this study, it is pointed that cause of the interference through channel environmental analysis, and effective application of propagation prediction model was carried out between neighboring countries. Between Korea and Japan, radio duct occurs on hold due to changes in the refractive gradient, and comfirmed occurrence of broadcasts interference. The results are presented that 1% time variable, -91.80 [N-units/km], 10% time variable, -43.92 [N-units/km], 50% time variable, -586.19 [N-units/km], for effective refractive gradient. Proposed refractive gradient could contribute to actual radio propagation prediction.

• Journal for History of Mathematics
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• v.19 no.1
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• pp.65-78
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• 2006

The law of refraction, which is called Snell's law in physics, has a significant meaning in mathematics history. After Snell empirically discovered the refraction law $\frac{v_1}{sin{\theta}_1}=\frac{v_2}{sin{\theta}_2$ through countless observations, many mathematicians endeavored to deduce it from the least time principle, and the need to surmount these difficulties was one of the driving forces behind the early development of calculus by Leibniz. Fermat solved it far advance of others by inventing a method that eventually led to the differential calculus. Historically, mathematics has developed in close connection with physics. Physics needs mathematics as an auxiliary discipline, but physics can also belong to the lived-through reality from which mathematics is provided with subject matters and suggestions. The refraction law is a suggestive example of interrelations between mathematical and physical theories. Freudenthal said that a purpose of mathematics education is to learn how to apply mathematics as well as to learn ready-made mathematics. I think that the refraction law could be a relevant content for this purpose. It is pedagogically sound to start in high school with a quasi-empirical approach to refraction. In college, mathematics and physics majors can study diverse mathematical proof including Fermat's original method in the context of discussing the phenomenon of refraction of light. This would be a ideal environment for such pursuit.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1998.09a
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• pp.78-83
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• 1998

흐름이 존재하는 수역을 파가 전파할 때 파는 흐름과의 상호작용에 의해 그 특성이 변형된다. 예를 들면 파와 흐름의 진행 방향이 같을 때는 파고의 감소, 반대일 때 파고의 증가로 나타난다. 후자의 경우 흐름에 의해 반사파가 생성될 것으로 사료되나 실제 해역에서 이러한 현상을 관측한 예는 거의 찾아보기 어렵다. 동해안의 경우 통상 관측지점에서 흐름의 세기가 작기 때문에 흐름에 의한 파의 굴절 현상이 잘 나타나지 않는다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 1988.06a
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• pp.47-54
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• 1988

아홉 개의 TEA Co 레이저선에 대한 암모니아 매질의 비선형 굴절계수 (n%)를, 매질을 통과한 광속이 self-focusing 또는 self-defocusing 에의해 겪게되는 공간적 광속 변화를 측정함으로써 결정하였다. 암모니아 매질을 통과하여 변형된 광속의 전장은 가우스 함수의 금수로 주어지는 스미스의 표현(5)으로 근사할수 있었으며, 실험치와 비교하여 보았다. 아홉 개의 레이저선중 여덟 개의 레이저선은 self-focusing 현상을 나타애렀으며9R(16) line은 self-defocusing 현상을 나타내었다.