Anomalous Beam Splitting Phenomena Based On Negative Refraction in Photonic Crystals

Chung, Kyo-Bang,Kim, Ahyoung Research Institute of Science and Technology HONGI 2005 Hongik Journal of Science and Technology Vol.9 No.-

We report an anomalous Y-branching phenomenon for normal incidence of light, in a 2D photonic crystal composed of dielectric rods arranged on a square lattice in air. From the calculation of the band structure and the corresponding equi-frequency contour, we examine the origin of this anomalous beam splitting. By performing the finite-difference time-domain simulation, we present the time evolution of the electromagnetic wave for the Y-branching phenomenon.

청국장에 관한 연구(Ⅰ) : 청국장 제조과정에 있어서 콩단백질의 변화에 대하여 On the changes of soy - bean protein in manufacturing Chung - Kook - Jang

이계호,이효지,정문교 한국농화학회 1971 Applied Biological Chemistry (Appl Biol Chem) Vol.14 No.3

As a series on the soy-bean protein and their related substances 9 samples were collected from 9 places such as straws (Rice) to obtain bacterial strains which produce protease. From these samples total of 23 strains were isolated by the use of dilution pour plate method. For all isolated strains primary screening of productivity of protease was performed and useful straines with regard to protease productivities were identified. Optimum conditions for enzyme action of protease from isolates D_9, F_(20) strains were pH 7.5 and 40℃. Chung-Kook-Jang is one of the characteristic foods in Korea made from soy-bean by fermentation. The chief bacterium is Bacillus subtilis and the chief change which takes place in soy-bean during fermentation is degradation of protein. Three kinds of Chung-Kook-Jang were prepared using three different strains of Bacillus natto, D_9 and F_(20) from isolated. Water soluble-N, TCA soluble-N, amino-N and peptide-N were measured about the steamed soybean, Chung-Kook-Jang prepared with three strains of bacteria. Water soluble-N decreased very largely in steamed soybean, but in Chung-Kook-Jang it increased to 85% of raw soy-bean.

2차원 광자 밴드 갭 구조의 유한 차분 시간 영역 모델링

鄭敎龐 弘益大學校 科學基術硏究所 1999 科學技術硏究論文集 Vol.10 No.2

In this paper, the transmission characteristics of a two-dimensional photonic bandgap crystal of finite size are computed with the finite-difference time-domain method, which is formulated with the total-field/scattered-field formulation and the Mur absorbing boundary condition for the two-dimensional TM case. The photonic crystal is composed of infinitely-long cylinders on a square lattice. Computed results confirm the existence of photonic bandgaps, and the variation of bandgaps with different parameters is observed. For the photonic crystals with missing cylinders, the transmission properties of one two defect modes are computed. The variation of defect-mode peaks inside the bandgap frequency is observed for various relative positions of defects.

농경지 토양의 토질요소와 평가 방법의 검토

정덕영,이교석 충남대학교 농업과학연구소 2005 농업과학연구 Vol.32 No.2

In agricultural ecosystem, soils which play important roles of storage and cycling of substances become a crtitical social problem due to rapid increase of contaminants with respect to our health. Soil as productivity should be interpreted as soil quality, that is important criteria in maintaining sustainable agriculture for production of safe food. Therefore, it needs to set the criteria of soil quality by considering environmental factors including relevant parameters which are involved in soil quality soil health because soils are widely distributed and have various characteristics such as physical, chemical, and biological propevties. Therefore, it requires intensive investigation of evaluation methods and development of related parameters for environmentally sound agriculture and safe soil management.

광자 크리스탈 채널드롭 터널링을 이용한 파장분할 소자에 대한 연구

鄭敎龐,吳世澤 弘益大學校 科學技術硏究所 2003 科學技術硏究論文集 Vol.14 No.-

We design a 1 X 4 wavelength demultiplexer based on channel drop tunneling in photonic crystals. We show the results of simulation of the demultiplexer device for tunneling properties of electromagnetic waves in a two-dimensional photonic crystal, with an application of the finite-difference time-domain method with perfectly-matched-layer absorbing boundary condition. We find four frequencies at which the channel drop tunneling occurs, and design a 1 X 4 wavelength demultiplexer based on the frequencies. To improve the channel drop transmission, we separate spurious reflections in photonic crystal waveguide simulations using a large computational domain, and obtain the results of highly efficient transmission.

광자 크리스탈 광 분배기의 수치 연산 해석

鄭敎龐,尹志秀 弘益大學校 科學技術硏究所 2001 科學技術硏究論文集 Vol.12 No.-

We design a 1-by-4 optical splitter made of photonic crystal waveguides and analyze the properties of the optical splitter using the finite-difference time-domain method with perfectly-matched-layer absorbing boundaries. The photonic crystal is constructed by cylindrical rods in air on a square lattice. Our simulation results show that there are different transmission properties for four bend geometries and different incident-wave frequencies, and the incident power splits in the four arms with almost the same ratio. Moreover, we perform numerical simulations of T-shaped waveguide branches to reduce the reflections at the T-branches in the splitter. The branching region is treated as a cavity that couples the input and output waveguides. The improvement of transmission is achieved by placing the defects of extra rods in the branching region.

디펙트를 보유한 2차원 광자 밴드 갭 구조의 파동 전달 특성

鄭敎龐 弘益大學校 科學技術硏究所 2000 科學技術硏究論文集 Vol.11 No.-

It has been observed that photonic bandgap crystals may work as functional photonic devices such as filters, waveguides, and microcavity lasers, if defects are inserted properly inside the structures. The work done to date has been concerned primarily with defects formed by removing rods in two-dimensional lattices. This paper presents the transmission characteristics of missing-rod defects and of circular, and square, and rectangular cross-section defects with different size and permittivity in a finite-size two-dimensional photonic bandgap crystal of square lattice. The transmission characteristics are computed numerically with the finite-difference time-domain method, along with the total-field/scattered-field formulation and the Mur absorbing boundafy condition.

유전체 미세 주기 구조에서의 광파 전파의 수치적 연구

鄭敎龐 弘益大學校 科學技術硏究所 1998 科學技術硏究論文集 Vol.9 No.2

In this paper, the algorithm of the finite- difference time-domain method with the total-field/scattered-field formulation and the Mur absorbing boundary condition for the two-dimensional TM case is established and programmed. The program is applied to the computation of the transmission characteristics of a two- dimensional photon bandgap structure composed of cylinders on a square lattice. Computed results confirm the existence of photonic bandgaps, and the variations of bandgaps with different parameters are observed.

흰쥐 재생간의 알콜대사효소들의 활성치

문교철,곽춘식,정성광,김여희 啓明大學校 醫科大學 1988 계명의대학술지 Vol.7 No.2

A study was made on the change in the activities of the following during 10 post-operative days: alcohol dehydrogenase of regenerating rat livers after 70% (median and left lateral lobes) partial hepatectomy. After partial hepatectomy in the rats, activities of regenerating liver alcohol dehydrogenase significantly increased in the sixth day. The activities of microsomal ethanol-oxidizing system in the regenerating liver markedly increased from the third day after partial hepatectomy. However, no significant changes in hepatic catalase was noted throughout the experiments. The activities of cytosolic and microsomal aldehyde dehydrognease in the regenerating liver significantly increased from the sixthe day and the third to the sixth day respectively, but mitochondrial aldehyde dehydrogenase showed no change.

定電壓下 黃酸一蓚酸 混酸浴 中에서의 交流에 依한 알루미늄板의 陽極酸化

金敎秀,張學良 嶺南大學校 工業技術硏究所 1974 연구보고 Vol.2 No.1

混酸治 中에서 交流에 依한 20V 定電壓 下에서 알루미늄板을 陽極酸化시켜 生成한 酸化皮膜의 性質, 溶出한 Al量 및 coating ratio等을 液溫과 液의 濃度 變化에 따라 各 單獨浴을 使用하였을 경우를 相互 比較 檢討하였던 바 混酸治의 경우 50℃의 高溫에서도 黃酸 單獨浴의 경우보다 A1의 溶出量은 적고, 生成 酸化皮膜의 두께, 耐磨耗性 및 耐蝕性等 그 特性値는 좋았으며, 또한 修酸 單獨浴보다 耐磨耗性은 越等하게 좋으며, 酸化皮膜은 더 두껍게 生成되었다. The properties of aluminum oxide film formed, the amount of dissolved Al, etc. in the process of anodic oxidation of aluminum plate in H₂SO₄-H₂C₂O₄(4:1) mixed acid bath with the use of A.C. at constant voltage of 20V were compared with those obtained in either H₂SO₄or H₂C₂O₄simple acid bath under otherwise identical conditions. As a result, it was revealed, in the mixed acid bath, that 1) the amount of dissolved Al was smaller than that in H₂SO₄simple acid bath at various concentrations and temperature of the baths. It is indicative of the inhibiting effect H₂C₂O₄on the dissolution of Al: 2) the thickness, and abrasion and corrosion resistances of the film formed were thicker than and superior to those of the film obtain either in H₂SO₄or particularly in H₂C₂O₄simple acid bath: and 3) the film having the satisfactory characteristic properties was obtained even at high bath temperature of 50℃, and the decrease in the characteristic values of the film formed was gradual over 50℃. Thus, bath temperature can be easily controlled.