http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
ON ANALYTICAL SOLUTION OF NON LINEAR ROLL EQUATION OF SHlPS
S. Rao TATA,Kuniaki SHOJI,Shigeo MITA,Kiyokazu MINAMI 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.2006 No.-
Out of all types of motions the critical motions leading to capsize is roll. The dynamic amplification in case of roll motion may be large for ships as roll natural frequency generally falls within the frequency range of wave energy spectrum typical used for estimation of motion spectrum. Roll motion is highly non-linear in nature. There are various representations of non-linear damping and restoring available in literature. In this paper an uncoupled non-linear roll equations with three representation of damping and cubic restoring term is solved using a perturbation technique. Damping moment representations are linear plus quadratic velocity damping, angle dependant damping and linear plus cubic velocity dependant damping. Numerical value of linear damping coefficient is almost same for all types but non-linear damping is different. Linear and non-linear damping coefficients are obtained form free roll decay tests. External rolling moment is assumed as deterministic with sinusoidal form. Maximum roll amplitude of non-linear roll equation with various representations of damping is calculated using analytical procedure and compared with experimental results, which are obtained from forced tests in regular waves by varying frequency with three wave heights. Experiments indicate influence of non-linearity at resonance frequency. Both experiment and analytical results indicates increase in maximum roll amplitude with wave slope at resonance. Analytical results are composed with experiment results which indicate maximum roll amplitude analytically obtained with angle dependent and cubic velocity damping are equal and difference from experiments with these damping are less compared to non-linear equation with quadratic velocity damping.
Kamada, K.,Nikl, M.,Kurosawa, S.,Shoji, Y.,Pejchal, J.,Ohashi, Y.,Yokota, Y.,Yoshikawa, A. Elsevier [etc.] 2016 Journal of luminescence Vol.169 No.2
Pr doped (Lu,Gd)<SUB>3</SUB>(Ga,Al)<SUB>5</SUB>O<SUB>12</SUB> single crystals were grown by the micro-pulling down (μ-PD) method. The crystals were greenish and transparent with 3.0mm in diameter, 10-30mm in length. Neither visible inclusions nor cracks were observed. Luminescence and scintillation properties were measured. The substitution at the Al<SUP>3+</SUP> sites by Ga<SUP>3+</SUP> in garnet structure has been studied. The Pr<SUP>3+</SUP> 5d-4f emission is observed within 300-380nm wavelength superposed with 312nm emission line of Gd<SUP>3+</SUP>. Pr0.2%:Lu<SUB>2.5</SUB>Gd<SUB>1</SUB>Ga<SUB>3</SUB>Al<SUB>2</SUB>O<SUB>12</SUB> shows highest emission intensity. The light yield of Pr0.2%:Lu<SUB>2.5</SUB>Gd<SUB>0.5</SUB>Ga<SUB>2</SUB>Al<SUB>3</SUB>O<SUB>12</SUB> sample with diameter 3mmx1mm size was around 8000ph/MeV. Two-exponential approximations of scintillation decay showed 39.6ns (30.6%) and 151ns (69.4%) decay times.