• 센서학회지
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• 제30권5호
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• pp.331-336
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• 2021

The Non-dispersive Infrared (NDIR) gas sensor has high selectivity, measurement reliability, and long lifespan. Thus, even though the NDIR gas sensor is expensive, it is still widely used for carbon dioxide (CO₂) detection. In this study, to reduce the cost of the NDIR CO₂ gas sensor, we proposed the new optical waveguide structure design based on ready-made gas pipes that can improve the sensitivity by increasing the initial light intensity. The new optical waveguide design is a structure in which a part of the optical waveguide filter is inclined to increase the transmittance of the filter, and a parabolic mirror is installed at the rear end of the filter to focus the infrared rays passing through the filter to the detector. In order to examine the output characteristics of the new optical waveguide structure design, optical simulation was performed for two types of IR-source. As a result, the new optical waveguide structure can improve the sensitivity of the NDIR CO₂ gas sensor by making the infrared rays perpendicular to the filter, increasing the filter transmittance.

• 천문학회보
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• 제37권1호
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• pp.93.2-93.2
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• 2012

Point Spread Function (PSF) is one of the most important optical characteristics for describing the performance of a telescope. And a concept of subpixelization is inevitable in evaluating the undersampled PSF (Shin and Sakurai 2009). Then, the internal structure of Yohkoh SXT CCD pixel is not uniform: For the top half of pixel area, the X-ray should pass a so-called gate structure where the charges are transferred to an output amplifier. This gate structure shows energy-dependent sensitivity (Tsuneta et al. 1991). For example, for Al-K (8.34 A) X-ray emission, the transmission of the polysilicon gate is about 0.9. Also, for the peak coronal response of the SXT thin filters, around 17 angstrom (0.729 keV), the transmission of the gate is about 0.6, falling off sharply towards longer wavelengths. It should be noted that this spectrally dependent non-uniform response of each CCD pixel will certainly have a noticeable effect on the properties of the PSF at longer wavelengths. Therefore, especially for analyzing the undersampled PSF of low energy source, a careful consideration of non-uniform internal pixel structure is required in determining the shape of the PSF core. The details on the effect of gate structure will be introduced in our presentation.

• 한국세라믹학회지
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• 제34권7호
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• pp.758-766
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• 1997

Non-brittle fracture behaviour of the two composite structures made of two different brittle materials was investigated using 3-point bending test. First, the layered and fibrous macro-composites were fabricated using the material easily formed, yet showing a brittle fracture behaviour similar to ceramics. The layered and fibrous Al2O3 /Al2O3 composites with weak interface were also fabricated using plate of 2 mm thickness and rod of 3 mm diameter respectively. Comparison of the mechanical properties between these two structures was performed in the lights of flexural strength and work of fracture for the composites consisting of Al2O3 and simulated materials respectively. The strength ratio of layered structure to the monolith of same volume was 0.6 and the ratio of fibrous one was about 0.2 for the composites made of simulated brittle material. The ratio of the work of fracture of the fibrous to the layered was 0.47. For Al2O3/Al2O3 composites, the strength ratio of layered and fibrous structures to the monolith with same volume were about 0.6 and 0.2 respectively. The ratio of work of fracture of the fibrous to the layered was 0.6. These confirmed that the layered structure was superior to the fibrous one in terms of flexural strength and work of fracture.

• Earthquakes and Structures
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• 제20권1호
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• pp.87-96
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• 2021

Ground motions recorded in near-fault sites, where the rupture propagates toward the site, are significantly different from those observed in far-fault regions. In this research, finite element modeling is used to investigate the effect of pile cap stiffness on the seismic response of soil-pile-structure systems under near-fault ground motions. The Von Wolffersdorff hypoplastic model with the intergranular strain concept is applied for modeling of granular soil (sand) and the behavior of structure is considered to be non-linear. Eight fault-normal near-field ground motion records, recorded on rock, are applied to the model. The numerical method developed is verified by comparing the results with an experimental test (shaking table test) for a soil-pile-structure system. The results, obtained from finite element modeling under near-fault ground motions, show that when the value of cap stiffness increases, the drift ratio of the structure decreases, whereas the pile relative displacement increases. Also, the residual deformations in the piles are due to the non-linear behavior of soil around the piles.

• 호남수학학술지
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• 제28권4호
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• pp.573-589
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• 2006

Let M be a real hypersurface with almost contact metric structure $({\phi},{\xi},{\eta},g)$ in a non flat complex space form $M_n(c)$. In this paper, we prove that if the structure Jacobi operator $R_{\xi}$ is ${\xi}$-parallel and the Ricci tensor S commutes with the structure operator $\phi$, then a real hypersurface in $M_n(c)$ is a Hopf hypersurface. Further, we characterize such Hopf hypersurface in $M_n(c)$.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 2부
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• pp.611-613
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• 2010

Constant Structure는 Non-Functional Harmony로써 현대 재즈에 적극적으로 사용되고 있다. 본 논문에서는 McCoy Tyner의 'Passion Dance'에서 Constant Structure Voicing이 어떻게 사용되었는지 분석하고, 이를 토대로 Constant Structure Voicing의 기초적 활용 방법을 연구한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1504-1508
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• 1996

In this paper, we derive dynamic equation of helicopter and design controller based on variable structure system. It is difficult to control helicopter because it has non-linear coupling between input and output of system and is MIMO system. The design of control law is considered here using variable structure methodology giving the robustness to parameter variations and invariance to some subsets of external disturbance. However we derive dynamic equations of helicopter and design stabilizing variable structure controller. Also, simulation results are given in this paper.

• 경영과정보연구
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• 제28권1호
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• pp.99-124
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• 2009

요즈음 환경에 대한 교육적 의미와 그린제품의 보다 많은 확산과 환경보호의 차원에서 그린광고의 필요성과 중요성이 증가되고 있음에도 불구하고 광고 전략상의 문제로서 특히 그린광고에 대한 연구가 거의 이루어지지 않은 점에 착안하여 소비자들의 환경에 대한 인식을 북돋우고 그린제품 구매자뿐만 아니라 비그린제품 구매자의 그린제품 구매를 유도한다는 차원에서 그린광고에 대한 연구를 하였다. 따라서 본 연구의 목적은 그린광고가 소비자태도에 미치는 영향에 대한 연구로서 특히 메시지구조(결론생략/제시)측면과 관여를 고려한 상황에서 그린광고가 어떠한 메시지구조로 이루어져 있을 때 효과적인가를 알아보기 위해 그린/비그린제품 광고가 소비자의 인지/감정/행도에 대한 태도에 따라 어떠한 차이를 보이는지를 알아보고, 그린/비그린제품 광고의 경우 메시지구조(결론생략/제시)에 따라 어떠한 차이를 보이며 어떠한 메시지구조를 취할 때 광고의 효과가 나타나는지를 살펴본다. 그리고 그린/비그린제품 광고의 관여(고/저)에 따라 차이를 보이는지를 분석하고 어떤 상황에서 어떠한 메시지구조를 선택하는 것이 효과적인지를 살펴본다. 즉, 수많은 광고에 노출되고 있는 소비자들이 그린광고에 대해서는 어떠한 시각을 갖고 있으며 그린광고의 형태에 메시지의 결론을 제시해서 설득적인 의도를 표현하는 것이 효과적인지 메시지의 결론을 생략해서 설득적인 의도를 숨기고 소비자들이 스스로 추론하고 정보탐색을 하도록 하는 메시지구조가 그린광고의 형태에 효과적인지를 밝혀서 앞으로의 그린광고의 제작 및 메시지구조 측면에 있어서 그린광고의 효과와 개선에 도움을 주고 그럼으로써 많은 그린제품 확산에도 기여하고자한다.

• Composites Research
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• 제31권4호
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• pp.161-170
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• 2018

원통형 복합재 격자 구조체는 필라멘트 와인딩 기법으로 제작되며 제작 공정에서 발생할 수 있는 섬유체적비 불균일과 수지응집층은 구조체의 강성도 및 강도에 영향을 줄 수 있다. 구조체의 주요 요소인 후프 및 헬리컬 리브의 단면 분석을 통해 섬유체적비 불균일 및 수지응집층의 존재 여부를 확인하였으며, 단면 분석 결과를 바탕으로 후프 및 헬리컬 리브에 대한 실험 및 이론적 접근을 통해 섬유체적비 불균일 및 수지응집층이 리브 요소의 강성도에 미치는 영향을 분석하였다. 섬유체적비 불균일이 후프 리브의 굽힘 거동에 영향을 미치는 것을 확인하였으며 헬리컬 리브의 경우 섬유체적비 불균일 및 수지응집층에 의해 강성도에 변화가 있음을 확인하였다.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1540-1555
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• 2021

The plate-type fuel assembly adopted in nuclear research reactor suffers from complicated effect induced by non-uniform irradiation, which might affect its stress conditions, mechanical behavior and thermal-hydraulic performance. A reliable numerical method is of great importance to reveal the complex evolution of mechanical deformation, flow redistribution and temperature field for the plate-type fuel assembly under non-uniform irradiation. This paper is the first part of a two-part study developing the numerical methodology for the thermal-fluid-structure coupling behaviors of plate-type fuel assembly under irradiation. In this paper, the thermal-fluid-structure coupling methodology has been developed for plate-type fuel assembly under non-uniform irradiation condition by exchanging thermal-hydraulic and mechanical deformation parameters between Finite Element Model (FEM) software and Computational Fluid Dynamic (CFD) software with Mesh-based parallel Code Coupling Interface (MpCCI), which has been validated with experimental results. Based on the established methodology, the effects of non-uniform irradiation and fluid were discussed, which demonstrated that the maximum mechanical deformation with irradiation was dozens of times larger than that without irradiation and the hydraulic load on fuel plates due to differential pressure played a dominant role in the mechanical deformation.