不同因素对可调节人工晶体屈光调节力的影响

首先以Hwey-Lan Liou眼模型为基础，根据等效性原则，保持该眼模型中自然晶状体屈光度不变，对无穷远点成像。然后利用ZEMAX实现光线追迹的方法，将自然晶状体替换为可调节人工晶状体（accommodative intraocular lens，AIOL），结合对人眼成像质量影响的分析，研究了AIOL在眼内的移动度、材料、中心厚度、结构、光学面非球面性等因素对其屈光调节力的影响。结果表明:AIOL移动度对其调节力贡献最大,材料、中心厚度、结构对调节力基本无影响；具有非球面光学面的AIOL调节力相对较大。     

人工晶体倾斜与偏心对人眼视功能的影响

基于Hwey-Lan Liou人眼生理模型,采用光线追迹的方法,分析了相同孔径下具有不同球差的人工晶体(IOL)在眼内的倾斜和偏心对人眼视功能的影响.IOL在眼内无倾斜和偏心时,负球差IOL对人眼视功能的改善优于无球差IOL和传统的正球差IOL;当IOL在眼内倾斜,偏心程度一定时,负球差IOL球差值越大,其倾斜和偏心对人眼视功能的降低越明显;植入无球差IOL的眼的视功能受其倾斜和偏心的影响较小,在IOL偏心1.0 mm,倾斜10°已使人眼有明显视觉不适的情况下,仍能表现出良好的光学性能,对人眼视功能的改善不仅优于正球差IOL,而且优于负球差IOL.     

具有层状晶状体的人眼模型的光学性质

为了更加符合眼睛的解剖学结构,用建立的层状结构晶状体模型代替了Hway-Lan Liou眼模型中的折射率连续变化的晶状体模型。从而建立了新的眼睛模型。在这个新的层状晶状体模型中,最外层前后表面的非球面系数与解剖学数据相符。由于层状结构使光线追迹具有特殊性。因此用C语言编制了光线追迹程序,并对此眼睛模型的光学性质进行了研究。结果表明,晶状体层数较少时,眼睛的球差曲线出现翼状结构．即层状晶状体的引入使眼睛具有多焦性．并对这种现象进行了解释;具有层状结构晶状体的眼睛和具有折射率连续变化的晶状体的眼睛能够给出等价的球差结果。     

基于锥形透镜的光线入射角度测量系统设计与研究

为测量光线入射角度,设计了一种基于锥形透镜的新型光线入射角度测量系统。利用光阑、锥形透镜和图像接收装置,获取待测光线通过光阑射入锥形透镜后经过多次的折射和反射,在图像接收装置上得到的复杂光斑图像,通过图像处理得到光斑图像特征信息,进而求解光线入射角度。采用锥形透镜的测量方案,角度测量范围可达80°,精度最高可达 (1×10?4)″。该方案结构简单、体积小且不需要进行繁琐的安装调试。与现有的单光点测量等方法相比,该方案中锥形透镜具有角度放大作用,可大幅度提高测量精度且具有大视场;图像传感器像素分辨率对测量结果影响较小,系统光通量大,容易获得较高的信噪比。     

LD面阵侧面泵浦Nd:YAG晶体吸收光场研究

为了研究LD面阵侧面泵浦Nd∶YAG晶体吸收光场的均匀性,本文提出了一种新的求解泵浦光路径的计算方法。首先建立了适用于不同泵浦结构的激光二极管多侧面泵浦全固态激光器的晶体吸收光场分布模型;然后模拟并分析了单向面阵泵浦结构各参量:bar条个数、bar条间隔、bar面倾斜程度对面阵泵浦晶体吸收光场均匀性及泵浦效率的影响。本文研究为LD侧面泵浦全固态激光器的设计和研究提供理论基础。     

激光束整形光学系统的设计与研究

提出了一种改善激光投线仪光束均匀性的新方法,该方法运用几何光线追迹的原理,对激光束通过带孔柱透镜的光路进行了计算,模拟了柱透镜内孔在不同大小、形状、透镜介质折射率等参数下的光束远场能量分布,获得了能量分布均匀的远场激光线.     

基于在轨成像物理机理的立体测绘相机建模与仿真

基于在轨成像物理机理的立体测绘相机成像建模与仿真综合考虑了大气辐射传输、卫星运行平台、光学系统成像、相机辐射响应等各个环节,采用数值模拟技术进行精确建模,可用于进行成像过程端到端的完整分析,评估成像系统设计可行性及成像质量。本文以可见光立体测绘相机为例,采用高精度高、分辨率地表物理模型作为输入源,首先结合立体测绘相机内外方位元素计算正视相机和前视相机CCD光敏面各亚像元区域中心的观测向量,然后根据目标相机的成像参数得到地面目标在相机入瞳处的辐亮度,最后通过光线追迹算法和光学系统点扩散函数模型计算探测器靶面的辐通量,经由探测器辐射响应模型得到数字影像。实验结果表明,正视相机几何物理模型定位精度达124 m,前视相机定位精度达193 m,能够较为可靠地模拟出立体影像,模拟方法可行。     

平行光栅对在刻线不平行时的色散研究

利用三维空间光线追迹法,分析了啁啾脉冲放大系统中的压缩光栅对,在刻线不平行而光栅面平行时光的衍射特性。导出了此时光通过光栅对的群延时,数值计算了系统2阶和3阶色散量,以及这些色散量在光栅对严格平行时的相对误差。得出了中心波长光的接收位置相对于光栅对严格平行时的偏移量,并且分析了它与入射角的变化关系。     

光线庞加莱球法构建的结构光场及其传输特性研究

结构光场在光信息传输、显微成像以及微粒俘获中有重要作用.本文基于光线庞加莱球法结合不同花瓣数的梅花曲线构建了一类结构光束.根据光线庞加莱球法可计算这类光束在束腰面上的光强与相位分布,以及光束内外焦散线的分布.这些焦散线的特征表明梅花形结构光束具有无衍射与自修复的特性.进一步采用角谱衍射法和光线追迹研究了这类光束在空间中的传输特性.当梅花花瓣数为0时,该光束退化为拉盖尔-高斯光束;当花瓣数为1时,内焦散线汇集到两点,使光束具有无衍射特性.通过光线庞加莱球法获得其光线在空间传播的轨迹,直观地展示了光束被遮挡后的自修复特性.此外,本文还展示了花瓣数为5的结构光束,其内焦散线为十角星结构,该光束同样具有自修复特性.通过修改梅花曲线参数或选择其他庞加莱球面曲线可以构造更加复杂的结构光场.     

平行光栅对在刻线不平行时的色散研究

 利用三维空间光线追迹法，分析了啁啾脉冲放大系统中的压缩光栅对，在刻线不平行而光栅面平行时光的衍射特性。导出了此时光通过光栅对的群延时，数值计算了系统2阶和3阶色散量，以及这些色散量在光栅对严格平行时的相对误差。得出了中心波长光的接收位置相对于光栅对严格平行时的偏移量，并且分析了它与入射角的变化关系。     

角膜手术后眼模型的构建和人工晶状体设计

根据角膜屈光手术前的角膜地形图、眼内各组分的轴向间距和波前像差,运用ZEMAX光学设计软件,构建了术前的个性化眼模型.结合角膜屈光手术后实际测量的波前像差,建立了术后个性化眼模型.运用该模型,为角膜屈光手术眼设计了双球面人工晶状体.研究表明:对于角膜屈光手术后人眼,用术后个性化眼模型计算的人工晶状体度数可靠.该模型还能够为术后眼设计矫正像散和其他高阶像差的人工晶状体,同时可以用来评估角膜手术联合白内障术后人眼的光学性能,以及手术中各类偏差对视觉质量的影响.     

基于人眼光学质量的球差和离焦补偿关系研究

基于人眼光学质量客观评估方法,通过实测的屈光手术前后人眼波前像差数据,研究和分析了球差与离焦的补偿关系。结果表明,对于屈光手术前的近视眼患者,离焦与球差的补偿关系并不明显。对于屈光手术后的近视眼患者,离焦与球差的补偿关系明显,残余离焦可以部分补偿由于高阶像差增加引起的视功能降低。当残余离焦处于0.27D～0.74D范围内,离焦与高阶像差组合后,光学质量提高了20%以上。在屈光手术方案设计时,预留0.27D～0.74D的离焦时,可以使80%的人眼达到更好的视觉矫正效果。     

The Relationship Between Chronic Cough and Paradoxical Vocal Fold Movement: A Review of the Literature

SUMMARY: Chronic cough (CC) and paradoxical vocal fold movement (PVFM) are debilitating conditions. PVFM has been given many labels, including vocal cord dysfunction, Munchausen's stridor, functional inspiratory stridor, nonorganic functional or psychogenic upper airway obstruction, factitious asthma, psychogenic stridor, emotional laryngeal wheezing, and episodic laryngeal dyskinesia. Although CC and PVFM have been considered separate entities in many reports, there is preliminary support for the notion that there may be an underlying link between these two conditions. Speech pathologists have become increasingly involved in the treatment of these patients and therefore need to understand the theoretical background of these disorders, the pathophysiological links between the two, and the impact of voice disorders on these populations. The aim of this article is to review the current literature on CC and PVFM from a speech pathology perspective to provide a model for defining and conceptualizing the disorders and to provide a framework for management and future research.     

The Relationship Between Dysphonia and Sinusitis: A Pilot Study

Though some clinicians believe chronic sinusitis is associated with dysphonia, studies confirming such a relationship are not available. This pilot study investigated vocal characteristics of chronic sinusitis patients compared to those of nonsinusitis patients. Nineteen male patients were evaluated in a single-blind, nonrandomized, prospective study at a Department of Veterans Affairs Medical Center. After candidates for the experimental and control groups were thoroughly screened [nasal and laryngology examinations, sinus computed tomography (CT) scan, history], 10 chronic sinusitis patients were assigned to the experimental group, nine patients without chronic sinusitis were assigned to the control group. Visi-Pitch analysis of their speech evaluated fundamental frequency, intensity, and perturbation. The evaluator described voice quality and vowel prolongation. Videostroboscopic examination evaluated glottic closure, supraglottic activity, vocal fold edge, amplitude, mucosal wave, and nonvibrating portion. Visi-Pitch analysis and vowel prolongation for each group was compared using an independent t-test. The average fundamental frequency mean was 113.43+/-32.75 Hz for the control group and 112.29+/-19.71 for the experimental group. This study established methods and parameters to determine if a relationship between chronic sinusitis and dysphonia actually exists. It did not establish a relationship between these entities, possibly due to the small sample size enrolled in the study, but determined that 126 subjects would be necessary to achieve significant results.     

双凸厚透镜曲率半径及焦距的测定探讨

利用双凸厚透镜的折反折成像,测定已知折射率的厚透镜前后表面的曲率半径及焦距。此方法可以修正测量透镜焦距忽略透镜厚度所产生的误差。     

Difference of Directions Between External Driving Force and Movement Direction of Center of Mass

Driven dynamics of a two-dimensional Frenkel-Kontorova model is studied in the paper. In our numerical simulations, it is found that the movement direction of the center of mass is not consistent with that of the external driving force except for some special symmetric directions at the lower driving force. Our results also indicate that the movement direction of the center of mass strongly depends on both the magnitude and the direction of the external driving force as well as the misfit angle between two layers.     

小麦条锈病胁迫下光合速率与光谱指数关系研究

为应用遥感技术进行小麦条锈病的实时监测以及大范围作物病害识别,明确条锈病胁迫下小麦光谱反射率和净光合速率与病情指数的关系,利用光谱植被指数预测小麦光合速率的变化,在2018年—2019年度冬小麦生长季节,以易感条锈病的济麦15号小麦品种为对照,以生产上播种面积较大的济麦22和鲁原502为供试品种,基于大田小区条锈病接种...     

Direct simulation Monte Carlo ray tracing model of light scattering by a class of real particles and comparison with PROGRA experimental results

The Direct Simulation Monte Carlo (DSMC) model is presented for three-dimensional single scattering of natural light by suspended, randomly oriented, optically homogeneous and isotropic, rounded and stochastically rough cubic particles. The modelled particles have large size parameter that allows geometric optics approximation to be used. The proposed computational model is simple and flexible. It is tested by comparison with known geometric optics solution for a perfect cube and Lorenz–Mie solution for a sphere, as extreme cases of the class of rounded cubes. Scattering and polarization properties of particles with various geometrical and optical characteristics are examined. The experimental study of real NaCl crystals with new Progra² instrument in microgravity conditions is conducted. The experimental and computed polarization and brightness phase curves are compared.     

农用地土壤As元素与叶片光谱特征关系研究

重金属污染是土壤环境污染中亟待解决的问题之一,重金属通过土壤向植物富集,危及人体健康,对生态环境产生巨大隐患.传统的土壤污染监测以化学方法为主,不仅费时费力且监测范围有限,而基于植被高光谱技术的土壤重金属监测方法能够快速准确地获取土壤重金属含量,突破植被屏障,提高土壤重金属监测效率.近年来,国内外许多学者致力于使用盆栽...