目的:观察儿童白内障摘除及人工晶状体植入后眼球及屈光状态的变化,探讨屈光状态变化的原因。方法:测量10例(12只眼)白内障患儿术前及术后(指本次随访时)的眼球轴长、角膜曲率及术后角膜顶点到人工晶状体前表面顶点的距离(The distance ...目的:观察儿童白内障摘除及人工晶状体植入后眼球及屈光状态的变化,探讨屈光状态变化的原因。方法:测量10例(12只眼)白内障患儿术前及术后(指本次随访时)的眼球轴长、角膜曲率及术后角膜顶点到人工晶状体前表面顶点的距离(The distance from the vertex of the cornea to the anteriorvertex of intraocular lens AVpc),比较术眼在手术前后的变化及与对照眼(未手术的对侧眼)在术前、术后的差异。在术后两周内及本次随访时检影,观察其人工晶状体眼屈光状态的变化。患儿手术时年龄7.16±1.94岁,随访时间平均35.8月(23～48月)。结果:术眼(n=12)眼轴长在术后平均增加0.39±0.48mm;对照眼(n=8)轴长增加0.66±0.68mm。术眼、对照眼在手术后眼轴长的增加均有显著的统计学意义(P<0.05),而术眼与对照眼的轴长增加量之间无显著性差异(P>0.05)。术眼、对照眼的角膜曲率在手术前后分别比较、双眼之间比较均无显著性差异(P>0.05)。术后测量的AVpc1为3.83±0.58mm,而估算的AVpc2为4.6630±0.2242mm,两者之间有显著的统计学差异(P<0.01),提示人工晶状体在眼内的位置前移0.8320±0.7441mm。根据手术前后眼轴长和角膜曲率值,按照SRKⅡ公式估算,在本次随访时人工晶状体眼有-1.53±1.70D(n=12,P<0.01)的屈光变化;展开更多
Based on the effective mass approximation, the Schrodinger equation and Poisson equation in GaAs/AlGaAs multi-quantum wells(MQWs) are self-consistently solved to obtain the wave functions and energy levels of electron...Based on the effective mass approximation, the Schrodinger equation and Poisson equation in GaAs/AlGaAs multi-quantum wells(MQWs) are self-consistently solved to obtain the wave functions and energy levels of electrons in the conduction band for the ground first excited state by considering a lateral electric field(LEF). Then, the effects of size, ternary mixed crystal, doping concentration, and temperature on linear and nonlinear intersubband optical absorption coefficients(IOACs), and refractive index changes(RICs) due to the transition between ground states and the first excited states of electrons are discussed based on Fermi’s golden rule. The results show that, under a fixed LEF, with increase of A1 composition and doping concentration, the IOACs produce a red shift. With increases of both widths of the wells and barriers IOACs appear as blue shifts and their amplitudes increase, but the barrier width change is much more important to affect nonlinear IOACs, whereas increasing the temperature results in a blue shift first and then a red shift of IOACs. When the other parameters are fixed but there is an increase in the LEF, IOACs occur with a blue shift, and the RICs have similar properties.展开更多
According to the Kukhtarev equations and a simplified model based on the photovoltaic charge carriers transport mechanism, the distributions of the index changes (DICs) in LiNbO3:Fe crystals induced by sheet beams wit...According to the Kukhtarev equations and a simplified model based on the photovoltaic charge carriers transport mechanism, the distributions of the index changes (DICs) in LiNbO3:Fe crystals induced by sheet beams with various intensity profiles are theoretically analyzed. The numerically simulated results coincide with the analytic expressions deduced from the simplified model. The DICs in a LiNbO3:Fe crystal induced by sheet beams with rectangular, Gaussian and square law profiles are measured by using the interferometric method. By employing the analytic expressions, the experimental data points are well fitted. By utilizing the angular spectrum theory and the ray equation, the uniformities of the intensity profiles of the writing beams along the propagation directions and the influences of the self-defocusing effect of the crystal are numerically simulated, respectively. The results show that the experimental results are reliable. The numerically simulated method and the analytic expressions can be both employed to predict the DICs induced by sheet beams with various light intensity profiles. Furthermore, utilizing writing beams with proper intensity profiles, any desired index distributions could be obtained.展开更多
文摘目的:观察儿童白内障摘除及人工晶状体植入后眼球及屈光状态的变化,探讨屈光状态变化的原因。方法:测量10例(12只眼)白内障患儿术前及术后(指本次随访时)的眼球轴长、角膜曲率及术后角膜顶点到人工晶状体前表面顶点的距离(The distance from the vertex of the cornea to the anteriorvertex of intraocular lens AVpc),比较术眼在手术前后的变化及与对照眼(未手术的对侧眼)在术前、术后的差异。在术后两周内及本次随访时检影,观察其人工晶状体眼屈光状态的变化。患儿手术时年龄7.16±1.94岁,随访时间平均35.8月(23～48月)。结果:术眼(n=12)眼轴长在术后平均增加0.39±0.48mm;对照眼(n=8)轴长增加0.66±0.68mm。术眼、对照眼在手术后眼轴长的增加均有显著的统计学意义(P<0.05),而术眼与对照眼的轴长增加量之间无显著性差异(P>0.05)。术眼、对照眼的角膜曲率在手术前后分别比较、双眼之间比较均无显著性差异(P>0.05)。术后测量的AVpc1为3.83±0.58mm,而估算的AVpc2为4.6630±0.2242mm,两者之间有显著的统计学差异(P<0.01),提示人工晶状体在眼内的位置前移0.8320±0.7441mm。根据手术前后眼轴长和角膜曲率值,按照SRKⅡ公式估算,在本次随访时人工晶状体眼有-1.53±1.70D(n=12,P<0.01)的屈光变化;
基金Project supported by the National Natural Science Foundation of China(No.61764012)
文摘Based on the effective mass approximation, the Schrodinger equation and Poisson equation in GaAs/AlGaAs multi-quantum wells(MQWs) are self-consistently solved to obtain the wave functions and energy levels of electrons in the conduction band for the ground first excited state by considering a lateral electric field(LEF). Then, the effects of size, ternary mixed crystal, doping concentration, and temperature on linear and nonlinear intersubband optical absorption coefficients(IOACs), and refractive index changes(RICs) due to the transition between ground states and the first excited states of electrons are discussed based on Fermi’s golden rule. The results show that, under a fixed LEF, with increase of A1 composition and doping concentration, the IOACs produce a red shift. With increases of both widths of the wells and barriers IOACs appear as blue shifts and their amplitudes increase, but the barrier width change is much more important to affect nonlinear IOACs, whereas increasing the temperature results in a blue shift first and then a red shift of IOACs. When the other parameters are fixed but there is an increase in the LEF, IOACs occur with a blue shift, and the RICs have similar properties.
基金supported by the National Natural Science Foundation of China(Grant No.60077018)the Youth for NPU Teachers Scientific and Technological Innovation Foundation,and the Postgraduate Seeds Foundation of NPU(Grant No.Z20030088).
文摘According to the Kukhtarev equations and a simplified model based on the photovoltaic charge carriers transport mechanism, the distributions of the index changes (DICs) in LiNbO3:Fe crystals induced by sheet beams with various intensity profiles are theoretically analyzed. The numerically simulated results coincide with the analytic expressions deduced from the simplified model. The DICs in a LiNbO3:Fe crystal induced by sheet beams with rectangular, Gaussian and square law profiles are measured by using the interferometric method. By employing the analytic expressions, the experimental data points are well fitted. By utilizing the angular spectrum theory and the ray equation, the uniformities of the intensity profiles of the writing beams along the propagation directions and the influences of the self-defocusing effect of the crystal are numerically simulated, respectively. The results show that the experimental results are reliable. The numerically simulated method and the analytic expressions can be both employed to predict the DICs induced by sheet beams with various light intensity profiles. Furthermore, utilizing writing beams with proper intensity profiles, any desired index distributions could be obtained.
基金Supported by National Science Fundation of China(60878002)the Science and Technology Committee of Guangdong Province(2010A080802002,2010B080704002,2010B010800031,2010B090400130 and 8251009101000002)the Science and Technology Bureau of Guangzhou(2009J1-C421-1)
