• 자연과학논문집
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• 제17권1호
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• pp.31-37
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• 2006

We have found that the polarization mode coupling between the orthogonally linearly polarized dual mode laser results from the anisotropy of dipole moments. Rate equation analysis demonstrated that high anisotropy in dipole moment components can give rise to law intrinsic mode coupling constants while isotropic dipole moment components give high intrinsic mode coupling constant. The populations at active ion sites are shown to self-organize the populations such that laser mode gain is constant adove threshold while the gain contributions from the each site adjust themselves with pump power.

• Journal of Photoscience
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• 제12권3호
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• pp.119-122
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• 2005

The photophysical properties of coumarin 6 laser dye have been studied in two solvents; ethanol and acetonitrile using steady-state fluorescence depolarization technique. The experimentally measured reorientation time of coumarin 6 is more or less the same in given solvents at particular temperature. It is found that coumarin 6 rotates slower in acetonitrile than in ethanol especially at higher values of viscosity over temperature. We also measure the ground and excited state dipole moments of coumarin 6 by solvent perturbation method. The results found that excited state dipole moment is greater than ground state dipole moment, which indicates that excited state is more polar than the ground state.

• Bulletin of the Korean Chemical Society
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• 제6권2호
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• pp.79-86
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• 1985

The complete neglect of differential overlap (CNDO/2) approximate wavefunctions have been applied to select the preferred signs for the dipole moment derivatives of SiH$_{4}$ and SiD$_{4}$ in conjunction with the experimental alternatives. The apparent sign discrepancy from earlier report has been identified. The effective atomic charge for hydrogen was found to be X$_{H}$/e = 0.229, more than two times larger in comparison with the values of typical hydrocarbons like CH$_{4}$. The anomalously large effective hydrogen charge was interpreted based on a quantum mechanical model as well as the value of atom anisotropy relative to effective atomic charge.

• 전기학회논문지
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• 제59권12호
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• pp.2245-2249
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• 2010

The physical properties of the LB films with merocyanine dyes have been published and attract attention due to the possibility of molecular structure control. The evaluation of the thin films was focused for the purpose of molecular structure control. The molecular structure in the case of the thin films with dyes can be examine by optical absorption spectra measurements. In the result measured by optical absorption spectra, the $[DX]_{1-x}[DO]_x$ LB films shows a large in-plane anisotropy and the transition dipole moment of red-shifted band is preferentially oriented perpendicular to the dipping direction of the film, while that of the blue-shifted band prefers the dipping direction. The spectrum for $0_{\circ}$, $90_{\circ}$-polarized light coincides with the spectrum for non-polarized light and also with the spectrum was observed in the LB film deposited using a fresh solution. These results show that the aging process does not cause a structural change in chromophore but a change in the degree of molecular orientation. In the results, study of the merocyanine dyes LB films using optical absorption spectra would an interesting problem of absorbance peak shifts and mixed components.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 추계학술발표회논문집(2)
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• pp.669-674
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• 1996

The theory of quantum mechanics states that for any system there are a set of discrete physical states, quantum states, which corresponds a particular energy level of the system. The lowest energy the system can have, corresponding to its ground state, is not necessarily zero, but depends only on the precise microscopic nature of the system under consideration. At the absolute zero of temperature all systems will be in their lowest energy state (zero point energy) and as the system is warmed from OK, the higher energy states become occupied. The probability of occupancy of the excited states relative to that of the ground state is proportional to the absolute temperature. Therefore we can obtain nuclear dipole and quadrupole moment very accurately at ultra low temperature (<15mk) by NMR and from the destruction of anisotropy. The former is called LTNO/NMR and the latter is called LTNO (Low Temperature Nuclear Orientation). In this paper we discuss and introduce only an experimental apparatus with results of cooling power test, a helium dilution refrigerator, which can reache 8mK, and an actual technique for the experiment, a theory and results will be presented in another papers.

• 한국자기학회지
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• 제18권5호
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• pp.180-184
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• 2008

이온빔 증착법으로 제작한 코닝유리(Corning glass)/Ta(5 nm)/NiFe(7 nm)/FeMn(25 nm)/Ta(5 nm) 다층박막 구조에서 반강자성체 FeMn층 증착시 인가한 일축 이방성 자기장 방향에 따른 강자성체 NiFe층의 자화 스핀배열 의존성을 조사하였다. NiFe층과 FeMn 층 증착시 인가한 자기장 방향을 달리한 각도는 각각 $0^{\circ},\;45^{\circ},\;90^{\circ}$였다. 용이축 MR(magnetoresistaice) 곡선으로부터 얻은 교환결합세기(Hex)는 증착 자기장 각도가 $45^{\circ}$일 때 40 Oe로, $90^{\circ}$일 때는 거의 0 Oe로 감소하였다. 반면에 곤란축 MR 곡선으로부터 얻은 $H_{ex}$ 값은 증착 자기장 각도가 $45^{\circ}$일 때 35 Oe로, 90o일 때는 79 Oe로 증가하였다. 강자성체 층의 용이축과 반강자성체 층의 일축 이방성 방향이 $90^{\circ}$ 차이가 나는 계면에서도 FeMn층이 NiFe층의 자기모멘트 스핀방향을 회전시켜 교환결합 이방성 효과가 발생함을 알 수 있었다.