• 대한기계학회논문집
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• 제19권5호
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• pp.1333-1339
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• 1995

Recently developed technique of measuring minor species concentration by using the modulation dip in broadband CARS has been applied to the flame structure study of methane/air premixed flames in a counterflow. This method used the modulation dip from the cold band CO Q-branch resonant signal superimposed on the nonresonant background. The measured CO concentration profile in a symmetric and unsymmetric methane/air premixed flames together with the velocity and temperature by using LDV and CARS have been compared with the numerical results adopting detailed chemistry modeling. The results show that there is a satisfactory agreement between the experimental data and numerical results for velocities, temperatures and CO concentrations. And the modulation dip technique of measuring minor species, such as CO is a viable tool for a quantitative measurement in a flame.

• Steel and Composite Structures
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• 제20권5호
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• pp.1087-1102
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• 2016

The paper proposes to characterize the free vibration behaviour of non-uniform cylindrical shells using spline approximation under first order shear deformation theory. The system of coupled differential equations in terms of displacement and rotational functions are obtained. These functions are approximated by cubic splines. A generalized eigenvalue problem is obtained and solved numerically for an eigenfrequency parameter and an associated eigenvector which are spline coefficients. Four and two layered cylindrical shells consisting of two different lamination materials and plies comprising of same as well as different materials under two different boundary conditions are analyzed. The effect of length parameter, circumferential node number, material properties, ply orientation, number of lay ups, and coefficients of thickness variations on the frequency parameter is investigated.

• 산업기술연구
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• 제19권
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• pp.227-233
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• 1999

Simple equations which can predict "exact" values of the natural frequency of vibration for the special orthotropic laminates are presented. Many laminates with certain orientations have decreasing values of $B_{16}$ and $B_{26}$ as the number of plies increases. Such laminates, with $D_{16}=D_{26}{\rightarrow}0$, including the laminates with anti-symmetric configurations can be solved by the same equation for the special orthotropic laminates. If the quasi-isotropic constants are used, the equations for the isotropic plates can be used. Use of some coefficients cab produce "exact" value for laminates with such configurations. Natural frequencies of the plate with varying aspect ratios is presented.

• 한국인지과학회:학술대회논문집
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• 한국인지과학회 2000년도 춘계 학술대회
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• pp.121-127
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• 2000

지금까지 상호 표현(reciprocal expressions)이나 상호성(reciprocity)의 개념에 대한 연구는 영어의 'each other'를 중심으로 이뤄졌다. 그런데 한국어의 상호 대명사 '서로'는 'each other'와 달리, 그 자체로 배분성(distributivity)을 갖지 않는다. 오히려 다양한 배분 표현들과 공기함으로써 상호성을 구체화한다. 특히, 배분적 양화사는 상호 표현이 쓰인 문장에 강한 상호성(strong reciprocity)을 부여한다. 이외에도 한국어의 상호성 실현에는 함께 쓰인 술어가 중요한 역할을 한다. 우선, 술어가 대칭적(symmetric)이거나, 상호 대명사(reciprocal)'서로'를 논항으로 취하면, 문장은 일차적으로 상호성을 갖게된다. 또한, 술어가 반가법(anti-additive)함수로서의 의미 특성을 갖는 경우는, 논항이 복수 연접 명사구로 구성되었을 때, 논항을 그룹(group)으로 해석하는 것을 선호한다. 본고는 상호성 술어(reciprocated predicates)와 배분적 양화사의 의미 기여를 중심으로, 한국어 상호 표현의 다양한 의미·통사적 특징을 밝히는 것을 목표로 하며, 이를 통해 상호성의 개념이 고정적이거나 문맥에 따라, 임의로 정해지는 무질서한 것이 아니라, 함께 쓰인 배분적 양화사나 술어의 의미 특성에 따라 합성적으로(compositionally) 실현되는 것임을 보이고자 하였다.

• 대한수학회논문집
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• 제27권1호
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• pp.7-13
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• 2012

In this paper we consider pseudo-BCK/BCI-algebras. In particular, we consider properties of minimal elements ($x{\leq}a$ implies x = a) in terms of the binary relation $\leq$ which is reflexive and anti-symmetric along with several more complicated conditions. Some of the properties of minimal elements obtained bear resemblance to properties of B-algebras in case the algebraic operations $\ast$ and $\circ$ are identical, including the property $0{\circ}(0{\ast}a)$ = a. The condition $0{\ast}(0{\circ}x)=0{\circ}(0{\ast}x)=x$ all $x{\in}X$ defines the class of p-semisimple pseudo-BCK/BCI-algebras($0{\leq}x$ implies x = 0) as an interesting subclass whose further properties are also investigated below.

• 비파괴검사학회지
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• 제27권6호
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• pp.582-590
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• 2007

Imperfectly jointed interface serves as mechanical waveguide for elastic waves and gives rise to two distinct kinds of guided wave propagating along the interface. Contact acoustic nonlinearity (CAN) is known to plays major role in the generation of these interface waves called generalized Rayleigh waves in non-welded interface. Closed crack is modeled as non-welded interface that has nonlinear discontinuity condition in displacement across its boundary. Mathematical analysis of boundary conditions and wave equation is conducted to investigate the dispersive characteristics of the interface waves. Existence of the generalized Rayleigh wave(interface wave) in nonlinear contact interface is verified in theory where the dispersion equation for the interface wave is formulated and analyzed. It reveals that the interface waves have two distinct modes and that the phase velocity of anti-symmetric wave mode is highly dependent on contact conditions represented by linear and nonlinear dimensionless specific stiffness.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.360-367
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• 2003

This paper presents passive vibration control method to suppress train-induced vibration on a long-span steel arch bridge. According to the train load frequency analysis, undesirable resonance of a bridge will occur when the impact frequency of the train axles are close to the modal frequencies of the bridge. Because the first mode shape of the long-span steel arch bridge may take anti-symmetric shape along the bridge direction, however, the optimal control configuration for resonance suppression should be considered carefully In this study, bridge-vehicle element is used to estimate the bridge-train interaction precisely. From the numerical simulation of a loom steel arch bridge under TGV-K train loading, dynamic magnification influences are evaluated according to vehicle moving speed and efficient control system with passive dampers are presented in order to diminish the vertical displacement and vertical acceleration.

• Bulletin of the Korean Chemical Society
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• 제7권1호
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• pp.59-62
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• 1986

Folded Box coherent anti-Stokes Raman spectroscopy (FBCARS) spectra of the fundamental symmetric stretch(213 $cm^{-1}$) and the first overtone(421 $cm^{-1}$) of $I_2$ have been recorded over the pump wavelength range from 495 nm to 580 nm. The lineshapes were fitted using the least squares method and the A and C term of CARS were calculated. From the fitting of A and C terms, the real(R) and imaginary(I) term intensity of CARS were calculated using harmonic oscillator program. The calculated CARS excitation profile of $I_2$ with R and I term data was about 270 $cm^{-1}$ red shifted from the absorption spectrum.

• Current Applied Physics
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• 제18권11호
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• pp.1182-1184
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• 2018

The combination of angular spin momentum with electronics is a promising successor to charge-based electronics. The conduction bands in GaAs may become spin-polarized via optical spin pumping, doping with magnetic ions, or induction of a moment with an external magnetic field. We investigated the spin populations in GaAs with x-ray magnetic circular dichroism for each of these three cases. We find strong anti-symmetric lineshapes at the Ga $L_3$ edge indicating conduction band spin splitting, with differences in line width and amplitude depending on the source of spin polarization.

• Structural Engineering and Mechanics
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• 제89권6호
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• pp.571-578
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• 2024

The bistable thin cylindrical shell is developable structure with the ability to transition between its two stable configurations. This structure offers significant potential applications due to its excellent deformability. In this paper, the composite thin cylindrical shell consisting of the composite layer and the piezoelectric layer was investigated. The material and geometric parameters of the shell were found to influence its stable characteristics. The analysis model of the composite thin cylindrical shell incorporating the piezoelectric layer was developed, and the expressions for its strain energy were derived. By applying the minimum energy principle, the impact of the electric field intensity on the bi-stable behaviors of the cylindrical shell was analyzed. The results showed that the shell exhibited the bistability only under the appropriate electric field strength. And the accuracy of the theoretical prediction was verified by simulation experiments. This study provides an important reference for the application of deployable structures.