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.

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.

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.

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.

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.

IMT-2000 망에서의 Layered Cell 전송 성능해석 모델

이영교,정해원,최충열,조성준 한국항공대학교 1997 論文集 Vol.35 No.-

본 논문은 ATM 기반의 layered 셀 구조를 적용한 Mobile Trunking에 사용되는 AAL type 2 프로토콜에 대해 설명했다. AAL type 2는 지연에 민감한 어플리케이션에 있어서 길이가 짧고, 패킷 길이가 변동하며, 저속도인 데이터 전송에 대한 대역폭 효율을 제공한다. 본 논문에서는 짧은 길이의 패킷에 대한 프레임 구조와 이를 하나 또는 그 이상의 ATM셀에 다중화 시키는 방식과 전송에러를 복구하는 기능 등에 대해서도 설명했고, 통계적 다중화의 효율, 지연, 채널전송효율 등을 해석하기 위한 큐잉 모델도 제안했다. 그리고, 미니셀 패킷화 지연 및 layered셀로 다중화되는 미니셀의 다중화 효율 등을 산출했고, layered셀 구조를 사용할 경우 예측되는 전송효율을 알아보았다. 여기서 전송속도는 ATM기반의 45Mbps에서 155Mbps사이의 경우를 고려하였다. 전송효율의 관점에서는 layered셀 방식이 고정 길이 셀 방식보다 효율적임을 알 수 있었다. 끝으로, 이를 국내 IMT-2000환경에 적용하기 위한 성능해석 모델과 파라미터를 제시하고 트렁크 용량을 해석했다. In this paper, we explaned the protocol of AAL type 2 used in the Mobile Trunking which has the layered cell structure based on ATM. These AAL type 2 provides the bandwidth-efficient transmission of low-rate, short, and variable length packets in delay sensitive applications. This paper covers the frame structure of the short legnth packets, the packing of those into one(or more) ATM cells, and the mechanisms to recover from transmission errors. Also, we proposed queueing model to analyse the efficiency of statistical multiplexing, delay time, channel transmission efficiency. And we calculated short cell packetization delay and short cell multiplexing into layered cells, and measured transmission efficiency to predict the layered cell structure schemes. Here we set the transmission line speed(trunking) at the between 45Mbps to 155Mbps, which are the future services bsed on ATM. From the viewpoint of transmision efficiency, layered cell shcemes is revealed to be more useful than fixed length cell schemes. Finally, we applied the proposed queueing model to the domestic IMT-2000 systems and we analysed the performance of trunk capacity.

맥아즙당도에 따른 효모의 특성

김교창,최병주,김도영,정준영 충북대학교 농업과학기술연구소 1993 農業科學硏究 Vol.10 No.2

The conclusion from experiments in the characteristic of yeast strain for selecting the appropriate yeast strain according to the variation of wort plato was as follows ; 1.CB8l, CB175 and CB89 yeast strain showed 73.3%, 72.6% and 73.0% in its limit fermentation, respectively. CB89 yeast strain showed the good result of 46.3% in the fermentation power test, also CB8l and CB175 yeast strains showed 33.1% and 24.0%, respectively. 2.In the yeast cell size CB8l, CB175 and CB89 yeast strain showed 8.4㎛, 8.8㎛ and 8.0㎛, respectively, and in the flocculation test those sedimentation content showed 0.6ml, 0.4ml and 8.5 ml, respectively after 10 minutes. CB89 yeast strain with high flocculation showed on appropriate result for brewing yeast. 3.Measured reducing sugar of each yeast after a day were observed as follows; CB8l, CB175 and CB89 yeast stain used up 33.3%, 42.6%, 61.1% of reducing sugar , respectively. 4.In ending fermentation, V. D. K(Vicinal Diketones) content and suspension yeast cell number of CB8l yeast strain showed 0.51-0.65ppm and 20-32×106cells/ml, respectively. Those of CB175 yeast strain showed 0.42-0.48ppm and 12-20×106cells/ml, respectively. CB89 yeast strain showed 0.58-0.69ppm and 34×106 cells/ml. 5.In ending fermentation, alcohol content of CB89 yeast was produced 4.55% and 5.05% was higher than that of CB8l and CB175 yeast. 6.CB89 yeast strain also showed about 300% of yeast recovery rate and 5.2% of dead cell rate which were good results.