可擦写型双层相变光盘的前记录层(激光入射面的记录层,或称前层)需要一个相变光记录层。该记录层具有高投射率的反射率反差[设结晶部的反射率为Rcry、非结晶部的反射率为Ramo,则反射率反差的定义为(Rcry-Ramo)/(Rcry+Ramo)]。从激光入...可擦写型双层相变光盘的前记录层(激光入射面的记录层,或称前层)需要一个相变光记录层。该记录层具有高投射率的反射率反差[设结晶部的反射率为Rcry、非结晶部的反射率为Ramo,则反射率反差的定义为(Rcry-Ramo)/(Rcry+Ramo)]。从激光入射面来看,该前层的结构依次是ZnS-SiO_2层、界面层、GeTe-Sb_2Te_3相变材料层(6nm)、界面层、Ag合金反射层(10nm)。和传统的结构相比,其特点是最上层为具有稿投射率的TiO_2层(20nm)。TiO_2层与反射层之间可产生光学干涉,非晶部和结晶部可实现高投射率,分别达到54％和51％。而且,为了增大反射率反差,采用使信号极性成为Rcry>Ramo的所谓“High to Low结构”,获得了超过0.7的巨大的反射率反差(Ramo=0.7％,Rcry=5.7％)。该前层采用波长405nm、NA=0.85的光学系统,记录最短标记(记录畴)长为0.149μm的1-7PP调制信号(双层相当于50GB的密度)时,在10mW的记录功率条件下,可获得7.4的抖晃值。展开更多
The principle of ocean wave spectrometers was first presented several decades ago to detect the directional wave spectrum with real-aperture radar(Jackson,1981). To invert wave spectra using an ocean wave spectrometer...The principle of ocean wave spectrometers was first presented several decades ago to detect the directional wave spectrum with real-aperture radar(Jackson,1981). To invert wave spectra using an ocean wave spectrometer,for simplicity,the hydrodynamic forcing and wave-wave interaction effect are neglected and a Gaussian slope probability density function(pdf) is used to calculate the normalized backscattering cross-section( σ 0) of the ocean surface. However,the real sea surface is non-Gaussian. It is not known whether the non-Gaussian property of the sea surface will affect the performance of the inversion of the wave spectrum if following existing inversion steps and methods. In this paper,the pdf of the sea surface slope is expressed as a Gram-Charlier fourth-order expansion,which is quasi-Gaussian. The modulation transfer function(MTF) is derived for a non-Gaussian slope pdf. The effects of non-Gaussian properties of the sea surface slope on the inversion process and result are then studied in a simulation of the SWIM(Surface Waves Investigation and Monitoring) instrument configuration to be used on the CFOSAT(China-France Oceanography Satellite) mission. The simulation results show that the mean trend of σ 0 depends on the sea slope pdf,and the peakedness and skewness coefficients of the slope pdf affect the shape of the mean trend of σ 0 versus incidence and azimuth; owing to high resolution of σ 0 in the range direction,MTF obtained using the mean trend of σ 0 is almost as accurate as that set in the direct simulation; in the inversion,if ignoring the non-Gaussian assumption,the inversion performances for the wave spectrum decrease,as seen for an increase in the energy error of the inverted wave slope spectrum. However,the peak wavelength and wave direction are the same for inversions that consider and ignore the non-Gaussian property.展开更多
The excitation function and angular distributions for the ^16O+^20Ne system have been explained using the distorted wave Born approximation (DWBA) calculations. The real and imaginary Woods Saxon optical potentials ar...The excitation function and angular distributions for the ^16O+^20Ne system have been explained using the distorted wave Born approximation (DWBA) calculations. The real and imaginary Woods Saxon optical potentials are assumed to be energy-dependent. The gross resonant structures observed in the ^20Ne(^16O,^16O)^20 Ne excitation function are well described by the present DWBA calculations. Although the elastic and elastic-transfer analyses introduce a qualitative description of the experimental data, the coherent sum of the two reaction processes exhibit a much better result for both forward and large-angle data.展开更多
文摘可擦写型双层相变光盘的前记录层(激光入射面的记录层,或称前层)需要一个相变光记录层。该记录层具有高投射率的反射率反差[设结晶部的反射率为Rcry、非结晶部的反射率为Ramo,则反射率反差的定义为(Rcry-Ramo)/(Rcry+Ramo)]。从激光入射面来看,该前层的结构依次是ZnS-SiO_2层、界面层、GeTe-Sb_2Te_3相变材料层(6nm)、界面层、Ag合金反射层(10nm)。和传统的结构相比,其特点是最上层为具有稿投射率的TiO_2层(20nm)。TiO_2层与反射层之间可产生光学干涉,非晶部和结晶部可实现高投射率,分别达到54％和51％。而且,为了增大反射率反差,采用使信号极性成为Rcry>Ramo的所谓“High to Low结构”,获得了超过0.7的巨大的反射率反差(Ramo=0.7％,Rcry=5.7％)。该前层采用波长405nm、NA=0.85的光学系统,记录最短标记(记录畴)长为0.149μm的1-7PP调制信号(双层相当于50GB的密度)时,在10mW的记录功率条件下,可获得7.4的抖晃值。
基金Supported by the National Science Foundation of China(No.40971185)the National High Technology Research and Development Program of China(863 Program)(No.2013AA09A505)
文摘The principle of ocean wave spectrometers was first presented several decades ago to detect the directional wave spectrum with real-aperture radar(Jackson,1981). To invert wave spectra using an ocean wave spectrometer,for simplicity,the hydrodynamic forcing and wave-wave interaction effect are neglected and a Gaussian slope probability density function(pdf) is used to calculate the normalized backscattering cross-section( σ 0) of the ocean surface. However,the real sea surface is non-Gaussian. It is not known whether the non-Gaussian property of the sea surface will affect the performance of the inversion of the wave spectrum if following existing inversion steps and methods. In this paper,the pdf of the sea surface slope is expressed as a Gram-Charlier fourth-order expansion,which is quasi-Gaussian. The modulation transfer function(MTF) is derived for a non-Gaussian slope pdf. The effects of non-Gaussian properties of the sea surface slope on the inversion process and result are then studied in a simulation of the SWIM(Surface Waves Investigation and Monitoring) instrument configuration to be used on the CFOSAT(China-France Oceanography Satellite) mission. The simulation results show that the mean trend of σ 0 depends on the sea slope pdf,and the peakedness and skewness coefficients of the slope pdf affect the shape of the mean trend of σ 0 versus incidence and azimuth; owing to high resolution of σ 0 in the range direction,MTF obtained using the mean trend of σ 0 is almost as accurate as that set in the direct simulation; in the inversion,if ignoring the non-Gaussian assumption,the inversion performances for the wave spectrum decrease,as seen for an increase in the energy error of the inverted wave slope spectrum. However,the peak wavelength and wave direction are the same for inversions that consider and ignore the non-Gaussian property.
文摘The excitation function and angular distributions for the ^16O+^20Ne system have been explained using the distorted wave Born approximation (DWBA) calculations. The real and imaginary Woods Saxon optical potentials are assumed to be energy-dependent. The gross resonant structures observed in the ^20Ne(^16O,^16O)^20 Ne excitation function are well described by the present DWBA calculations. Although the elastic and elastic-transfer analyses introduce a qualitative description of the experimental data, the coherent sum of the two reaction processes exhibit a much better result for both forward and large-angle data.
