• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1363-1365
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• 2001

다공질 실리콘(PSi)의 형성방법중에 가장 주된 방식인 전기화학법은 매우 범용화된 기술이다. 이러한 전기화학법을 이용한 PSi 제작방식에 있어 HF 가 함유된 전해액과 첨가되는 첨가제는 PSi 형성에 매우 중요한 역할을 한다. 전해액에 첨가되어지는 첨가재는 종류에 따라 전해질과 기판사이의 친수성 및 전해액의 표면장력을 작게 하는 역할을 하며, 그 밖의 기판 표면 상태변화의 원인으로서 양극산화 공정에 많은 변수로 작용한다. 본 논문에서는 기존의 에틸알콜을 함유한 HF 전해액과 새로운 용매를 함유한 HF 전해액에 대한 PSi의 형성을 광학 현미경 사진과 시간에 따른 전류 및 전압 특성 곡선으로 비교 분석하였으며, 기존 식각 용액을 사용했을 경우의 표면 식각현상과 형성구조의 불균일성 등을 해결할 수 있었다.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2761-2763
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• 2002

원자력발전소에서는 건설완료 단계에서 기기, 배관 및 각종 지지구조물에 대하여 PSI(Pre-Service Inspection)를 실시하여 시공된 설비의 건전성을 점검하고, 운영중에는 주기적으로 시간의 경과에 따른 취약화 정도를 비과괴검사로 감시 및 평가하는 ISI (In-Service Inspection)를 실시하여 안전성 관련 설비의 건전성을 점검하고 있다. 이 과정에서 방대한 양의 검사데이터가 생산되며 원전 가동년수가 증가함에 따라 검사자원을 체계적으로 관리하고 자동화 할 수 있는 시스템 개발이 필요하게 되었다. 본 논문에서는 PSI/ISI 검사결과 정보관리를 비롯하여 검사 기초자료 관리 및 검사계획 수립, 파괴역학 분식 기능 등을 포함한 Web 기반의 Application 개발 사례를 소개한다. 또한 가상현실 기법을 적용하여 기존의 2차원적 DB 운영을 3차원 가상공간에서 운영할 수 있는 'Touch & Tell' 기법을 개발하고 그 구현방법을 제시한다.

• Bulletin of the Korean Mathematical Society
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• v.52 no.5
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• pp.1711-1719
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• 2015

We obtain a new criterion for the boundedness and compactness of the weighted composition operators ${\psi}C_{\varphi}$ from ${\ss}^{{\alpha}}$(0 < ${\alpha}$ < 1) to ${\ss}^{{\beta}}$ in terms of the sequence $\{{\psi}{\varphi}^n\}$. An estimate for the essential norm of ${\psi}C_{\varphi}$ is also given.

• Bulletin of the Korean Mathematical Society
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• v.47 no.1
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• pp.103-111
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• 2010

In the present paper, we give two new proofs for the necessary and sufficient condition $\alpha\leq1$ such that the function $x^{\alpha}[lnx-\psi(x)]$ is completely monotonic on (0,$\infty$).

• Honam Mathematical Journal
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• v.23 no.1
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• pp.51-57
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• 2001

Let $\mathcal{B}(H)$ and $\mathcal{B}(K)$ denote the algebras of all bounded linear operators on Hilbert spaces $\mathcal{H}$ and $\mathcal{K}$, respectively. We show that if ${\phi}:\mathcal{B}(H){\rightarrow}\mathcal{B}(K)$ is an additive mapping satisfying ${\phi}({\mid}A{\mid}^2)={\mid}{\phi}(A){\mid}^2$ for every $A{\in}\mathcal{B}(H)$, then there exists a mapping ${\psi}$ defined by ${\psi}(A)={\phi}(I){\phi}(A)$, ${\forall}A{\in}\mathcal{B}(H)$ such that ${\psi}$ is the sum of $two^*$-homomorphisms one of which C-linear and the othere C-antilinear. We will also study some conditions implying the injective and rank-preserving of ${\psi}$.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.183-189
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• 2011

An alignment algorithm for strapdown inertial navigation systems is proposed, in which the psi angle error model is utilized. The proposed alignment algorithm is derived from the Psi angle error model which has been widely used in real-time navigation systems. The equation for expecting steady state alignment error is also derived. The proposed algorithm was verified through real-time experiments. Experimental results show that the proposed algorithm can be used in the inertial navigation system and GNSS/INS integrated navigation system to get an initial attitude of the vehicle.

• Journal of Electrochemical Science and Technology
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• v.7 no.3
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• pp.218-227
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• 2016

The light harvesting efficiency is counted as an important factor in the power conversion efficiency of DSSCs. There are two measures to improve this parameter, including enhancing the dye-loading capacity and increasing the light trapping in the photoanode structure. In this paper, these tasks are addressed by introducing a macro-porous silicon (PSi) substrate as photoanode. The effects of the novel photoanode structure on the DSSC performance have been investigated by using energy dispersive X-ray spectroscopy, photocurrent-voltage, UV-visible spectroscopy, reflectance spectroscopy, and electrochemical impedance spectroscopy measurements. The results indicated that bigger porosity percentage of the PSi structure improved the both anti-reflective/light-trapping and dye-loading capacity properties. PSi based DSSCs own higher power conversion efficiency due to its remarkable higher photocurrent, open circuit voltage, and fill factor. Percent porosity of 64%, PSi(III), resulted in nearly 50 percent increment in power conversion efficiency compared with conventional DSSC. This paper showed that PSi can be a good candidate for the improvement of light harvesting efficiency in DSSCs. Furthermore, this study can be considered a valuable reference for more investigations in the design of multifunctional devices which will profit from integrated on-chip solar power.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.483-494
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• 2006

In this paper, we propose a novel program specific information structure(PSI) in MPEG-2 system for a three-dimensional broadcasting system while guaranteeing compatibility with the conventional digital broadcasting system. The proposed PSI structure including a descriptor of contents type, 2D or 3D, provides service providers with a function of combining 2D and 3D contents freely. However the descriptor is ignored in the conventional digital broadcasting set-top box. With the proposed PSI structure, we designed and implemented a three-dimensional broadcasting system. The proposed system has 2D or 3D display mode for providing user's preference in a three-dimensional broadcasting environment.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.1
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• pp.1-7
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• 1981

A set of equations of a water transport model of the soil-plant system was described as an electrical circuit using the Ohm's analogy assuming that the transpirational pull be the main source of the driving force and the resistance be proportional to the inverse of the hydraulic conductivity of the catenary. The effective root resistance ($\hat{R}_{\tau}$) and the effective soil water potential ($\hat{\psi}_s$)were defined with the solution of the system; $$\hat{\psi}_s-\hat{R}_{\tau}g_{\tau}={\psi}_0$$ and the validity of the solution of the equation was demonstrated with the data obtained from a soybean field. ${\psi}_s$ and $R_{\tau}$ explained more reasonably than the average values taken so far. Therefore, the solution will describe the soil water status and the root resistance in terms of water transport in the soil-plant system.

• Journal of the Korean Wood Science and Technology
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• v.11 no.3
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• pp.3-13
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• 1983

Fiber mats were made at five density levels, using fibers from kraft pulp screening rejects, rice straw and a 50/50 mixture of the two. They were soaked in the sulfur compounds. Specimens cut from the composite panels were tested in flexure at time intervals for one year to study the effect of aging. Modulus of elasticity (MOE) and modulus of rupture (MOR) were determined. Under optimum conditions of fiber mat preparation and saturation with molten sulfur and modified sulfur, composites were produced which exhibited mechanical properties comparable to conventional fiberglass in some properties and superior to conventional wood-based composition boards, For example. the moduli of elasticity of the reinforced composites made from pulp screening rejects, with a density of 0.35 gm/$cm^3$, were greater than 1,000,000 psi as compared 800.000 psi for high-density hardboard (1.28 gm/$cm^3$). Modulus of rupture of the best reinforced composites was about 7,000 psi, comparable to 6,000 psi of high-density hardboard.