Nd~(3 ):YAG调Q倍频激光对视网膜损伤阈值的研究

本文介绍Nd~(3 ):YAG调Q倍频激光对青紫蓝灰兔视网膜损伤阈值研究的材料、方法和结果.曝光时间8×10~(-9)s,ED_(50)为232.05μJ/cm~2.     

连续Nd~(3 ):YAG激光对视网膜损伤阈值的研究

连续Nd~(3 ):YAG激光照射青紫蓝灰兔眼100只,1000个照射点,求得照射时间平均1.02s及0.12s,检眼镜可见视网膜损伤阈值,其ED_(50)分别为角膜平均入射2.52W/cm~2及5.42W/cm~2.     

CO_2激光对角膜损伤阈值的研究

用连续CO_2激光器,照射青紫蓝灰兔眼142只.求得平均照射时间1.03秒,角膜损伤阈值ED_(50)(?)5.72W/cm~2(95%可信限5.58～5.85W/cm~2);平均照射0.12秒,ED_(50)(?)10.7W/cm~2(95%可信限10.4～10.9W/cm~2).     

长脉冲红宝石激光对视网膜损伤阈值的研究

实验用长脉冲红宝石激光照射青紫蓝灰兔眼76只,求得视网膜凝固性损伤阈值,其ED_(50)为14.gmJ/cm~2,95%可信限13.6～16.5mJ/cm~2.     

308nm紫外激光对兔眼角膜损伤的延迟反应和损伤阈值研究

308 nm 紫外激光照射青紫蓝灰兔眼所引起的角膜损伤,观察到损伤呈两种反应:瞬时反应和延迟反应,并测量了延迟反应的剂盐水平。统计了受照24小时内角膜发生的损伤点,经概率统计分析,获得角膜瞬时损伤阈值 ED_(50)=0.485J/cm~2(95%置信限为0.349～0.608J/cm~2)。     

CO_2激光对兔眼角膜损伤阈值的研究

本文介绍连续CO_2激光对青紫蓝灰兔角膜损伤阈值研究的材料、方法和结果.辐照1秒,ED_(50)为3.62W/cm~2;辐照125ms,ED_(50)为4.01W/cm~2.     

Nd：YAG三倍频,四倍频激光对兔角膜损伤阈值研究

本文报导了Nd:YAG三倍频(355nm)及四倍频(266nm)紫外激光的兔角膜损伤阈值,其ED_(50)分别为404.8mJ/cm~2和43.7mJ/cm~2。     

红宝石激光辐照人皮肤损伤阈的实验

本文报道了红宝石激光辐照人皮肤的实验结果.将照后24小时内发生的红斑经统计学处理,其ED_(50)为4.7J/cm~2.     

488毫微米氩离子激光对动物视网膜损伤阈值的实验研究

本文报道了波长488nm的氩光对兔及猴眼视网膜损伤的实验研究结果;求得氩激光通过前置镜及平行光后的ED_(50)值;并测定出在这两种照射光束条件下的角膜及视网膜上的光斑直径.     

连续波Nd:YAG激光对人皮肤损伤阈值的研究

连续波1.06μm激光的损伤阈值经过动物实验及人皮肤实验.最后结果:中国人皮肤偏白者MRD_(50)为65.519J/cm~2,黄皮肤为60.989J/cm~2,偏黑者52.321J/cm~2.实验证明,皮肤色素的多少对Nd:YAG激光的吸收有明显的差异.     

电导率对旋波介质吸波性能的影响

旋波介质的吸波性能与介质的手性参量有关,而手性参量又与介质的电导率有关。制备了4种不同电导率基底的旋波介质,根据自由空间测量旋波介质手性参量的方法,通过测量两次复反射系数、透射偏转角和椭偏率,计算得到介质的手性参量和吸波性能。结果表明,改变旋波介质基底的电导率,可以调节旋波介质的电磁性能和吸波性能,当基底的电导率为4.2×10–2 S/cm时,旋波介质的吸波效果最好,其反射系数的最小值达–24 dB。     

Automatic diagnosis of multiple fundus lesions based on depth graph neural network

Fundus images are commonly used to capture changes in fundus structures and the severity of fundus lesions, and are the basis for detecting and treating ophthalmic diseases as well as other important diseases. This study proposes an automatic diagnosis method for multiple fundus lesions based on a deep graph neural network (GNN). 2 083 fundus images were collected and annotated to develop and evaluate the performance of the algorithm. First, high-level semantic features of fundus images are extracted using deep convolutional neural networks (CNNs). Then the features are input into the GNN to model the correlation between different lesions by mining and learning the correlation between lesions. Finally, the input and output features of the GNN are fused, and a multi-label classifier is used to complete the automatic diagnosis of fundus lesions. Experimental results show that the method proposed in this study can learn the correlations between lesions to improve the diagnostic performance of the algorithm, achieving better performance than the original ResNet and DenseNet models in both qualitative and quantitative evaluation.     

An Image Based Auto-Focusing Algorithm forDigital Fundus Photography

In fundus photography, the task of fine focusing the image is demanding and lack of focus is quite often the cause of suboptimal photographs. The introduction of digital cameras has provided an opportunity to automate the task of focusing. We have developed a software algorithm capable of identifying best focus. The auto-focus (AF) method is based on an algorithm we developed to assess the sharpness of an image. The AF algorithm was tested in the prototype of a semi-automated nonmydriatic fundus camera designed to screen in the primary care environment for major eye diseases. A series of images was acquired in volunteers while focusing the camera on the fundus. The image with the best focus was determined by the AF algorithm and compared to the assessment of two masked readers. A set of fundus images was obtained in 26 eyes of 20 normal subjects and 42 eyes of 28 glaucoma patients. The 95% limits of agreement between the readers and the AF algorithm were ${-}2.56$ to 2.93 and ${-}3.7$ to 3.84 diopter and the bias was 0.09 and 0.71 diopter, for the two readers respectively. On average, the readers agreed with the AF algorithm on the best correction within less than $3/4$ diopter. The intraobserver repeatability was 0.94 and 1.87 diopter, for the two readers respectively, indicating that the limit of agreement with the AF algorithm was determined predominantly by the repeatability of each reader. An auto-focus algorithm for digital fundus photography can identify the best focus reliably and objectively. It may improve the quality of fundus images by easing the task of the photographer.      

基于移动智能终端的便携式眼底图像检测仪

提出了一种便携式眼底图像检测系统,连接在移动智能设备上对眼底图像进行拍摄、存储、显示和解析。采用紧凑精密的光路结构开发了基于Android的图像处理与解析软件,并通过智能终端自带的远程消息发送软件,可将眼底图像远程传送给专业医生进行临床诊断。仿真结果表明,照明均匀性超过85%,杂散光在2%内。实验结果表明,该检测仪光学系统的视场为45°、工作距离为30 mm、总长度＜180 mm,可实现眼光焦度补偿范围为-10～+5 m-1,成像清晰,畸变＜6%。实现了对眼底检查的远程移动医疗。     

低强度超声对鼻咽癌细胞生物学效应的研究

目的：研究不同剂量低强度超声对人低分化鼻咽癌细胞CNE-2的急,、慢性生物学效应。方法：人鼻咽癌细胞CNE-2受不同剂量、频率为1.7MHz的超声波辐照,利用台盼兰染色法确定三种未致细胞急性损伤的超声剂量,并观察受此三种剂量超声辐照后细胞的增殖能力以及克隆形成力的变化。结果：0.30W/cm^2×35s、0.65W/cm^2×10s和1.35W/cm^2×5s未致细胞急性死亡。受0.30W/cm^2×35s、0.65W/cm^2×10s、1.35W/cm^2×5s辐照及对照组细胞倍增时间分别为：15.8h、23.6h、31.6h和22.9h;克隆形成率分别为：（41.54±1.48）%、（25.41±1.70）%、（15.62±1.60）%和（28.03±1.2）%。受0.30W/m^2×35s辐照后细胞增殖和克隆形成较对照组均有所增加,受1.35W/cm^2×5s辐照后细胞增殖和克隆形成较对照组均受到抑制。（p〈0.05）结论：CNE-2细胞对超声敏感性高,其生物学效应取决于超声剂量。     

眼底造影荧光强度的计算机定量分析

目的 :建立眼底血管荧光造影 (fundusfluoresceinangiography ,FFA)中荧光强度定量图像分析方法 ,以评价眼底病变的病变程度和预后。方法 :分析湿性增龄性黄斑变性 (age -relatedmaculardegeneration ,AMD)患者FFA图像脉络膜新生血管膜 (choroidalneovascularizition ,CNV)渗漏强度在造影各期的变化趋势 ,分析正常眼底后极部 6.2 0mm2 区域的FFA荧光强度在造影各期的变化趋势 ,二者进行比较 ,验证荧光强度定量分析方法的客观性、有效性和实用性。结果 :湿性AMD患者的FFA图像CNV荧光素渗漏强度造影各期均显著高于正常眼底后极部 6.2 0mm2 区(P <0 .0 5或P <0 .0 1) ,动静脉期至 72 0秒差别具有非常显著性意义 (P <0 .0 1)。 180秒～ 3 0 0秒差别最明显。结论 :对眼底疾病的病变程度和预后进行评估 ,荧光强度计算机定量图像分析方法是比较客观、有用的方法     

激光辐照对冷冻精子活率和活力的影响

分别用7.48J/cm~2和14.96J/cm~2能量密度的氦氖激光辐照23份液氮冷冻前人的精液,冻贮三个月后复温查精子活率和毛细管穿透高度。结果:经7.48J/cm~2剂量的激光辐照后的精子活率和穿透高度明显提高,分别平均提高10.18％和8.32mm,与未受辐照组比较差异显著(P<0.05)经14.96J/cm~2辐照组,活率较未照组降低。实验结果说明适当剂量的激光辐照能够增强精子对冷冻的耐受力,提高精子的复活率和活动力。     

Scanning Laser Ophthalmoscope

An instrument is described which functions as a low light level ocular fundus camera and ophthalmoscope, and which is capable of making a wide range of quantitative measurements in the eye. Light levels for ophthalmoscopy (20 ?W/cm2 at the retina) are at least two orders of magnitude below those in current use. A focused laser bearn forms a flying spot, moved physically by scanning mirrors. This allows a 20 ?m or smaller resolution element, with only a 0.9 mm diameter area of the patient's pupil used for the entering beam. The remaining pupillary area forms the exit pupil?a critical inversion of the division of pupils necessary for systems using conventional imaging. It is this inversion which allows the low light level and the unique measurement capabilities. We discuss the constraints imposed by viewing the inside of a spheroid through a small hole in its wall, and our solutions?both optical and electronic?to these problems. We also describe electronic problems encountered in the video system, which arise from our special detection and display systems. Some specifics of the instrument's measurement capabilities are discussed.     

CO2laser annealing of Si3N4, Nb2O5, and Ta2O5thin-film optical waveguides to achieve scattering loss reduction

Significant reductions in the optical scattering losses of Si3N4, Nb2O5, and Ta2O5waveguides fabricated on SiO2/Si substrates have been measured following CO2laser annealing. The largest improvements were observed for Si3N4waveguides, where waveguide attenuation values of about 6.0 dB/cm before laser annealing were reduced to as low as 0.1 dB/cm afterwards. An improvement of more than an order of magnitude was obtained for a Nb2O5waveguide upon laser annealing, the attenuation coefficient decreasing from 7.4 to 0.6 dB/cm. In the case of one Nb2O5waveguide no improvement was obtained upon laser annealing. The attenuation coefficient of a reactively sputtered Ta2O5waveguide was found to decrease from 1.3 dB/cm before laser annealing to 0.4 dB/cm afterwards. In the case of a thermally oxidized Ta2O5waveguide a small initial improvement in waveguide attenuation was followed by degradation upon further laser annealing.     

Bi_(3.5)Yb_(0.5)Ti_3O_(12)铁电薄膜的制备及性能

采用溶胶-凝胶(Sol-Gel)法在Pt(111)/Ti/SiO2/Si(100)基片上淀积了Bi3.5Yb0.5Ti3O12(BYT)铁电薄膜,研究了在不同退火温度下形成的BYT薄膜的微观结构以及铁电性能方面的区别。结果发现,在610,660,710和760℃不同温度下退火的BYT薄膜的结晶度不同,退火温度越高的BYT薄膜,其结晶度越高。并且发现,BYT薄膜的剩余极化值(2Pr)在710℃以下随退火温度增高而增大,在710℃达到最大;在外加400kV/cm电场时2Pr为36.7μC/cm2,然后随退火温度上升又有所下降。