声子晶体的负折射成像已成为当今国内外研究的热点问题.首先通过分析弹性波激励声子晶体元胞的局域共振响应特性,计算了局域共振型声子晶体的带隙特性,以此为基础构建了声子晶体相应的实验模型.然后基于Comsol仿真平台,把声子晶体元胞在XY平面内排列成声子晶体板后,模拟了近场点声源通过声子晶体板的负折射声成像过程.同时计算了模拟两个理想点声源经过声子晶体板后负折射成像的特性.仿真结果表明:声子晶体能较好地分辨两个点声源所成的像,点像的最小分辨率可达到0.2λ,很好地突破了声学成像中的衍射极限.

The negative refraction imaging of phononic crystal has become a research focus at home and abroad .Localized resonant resonance characteristics of elastic wave excitation phononic crystal cell were analyzed ,and the phonon crystal band gap was calculated ,on this basis ,corresponding ex-perimental model of phononic crystal was built .Based on comsol simulation platform ,the phononic crystal cell were arranged as phononic crystal plate in XY plane ,and negative refraction acoustic im-aging process was simulated when near field acoustic source past through phononic crystal plate .Nega-tive refraction imaging characteristics was obtained when two ideal point sound source past through the phononic crystal plate .Simulation results show that phononic crystals can distinguish better the image which is made by two sound source ,the minimum resolution can reach 0 .2λ,so it can make a breakthrough in the diffraction limit of the acoustic imaging .

目的 探讨硬性透气性角膜接触镜(RGPCL)在眼表面的形状稳定性及角膜形态对其的影响.方法 22名志愿者42只眼,用鹰式角膜地形图测量角膜像差后给予验配RGPCL,同样仪器测量RGPCL的像差后派发给志愿者,连续配戴1个月后回访,分别测量戴镜状态下以及摘镜30 min后的角膜地形图.采用配对t检验、W检验及相关分析对数据进行分析.结果 RGPCL戴到眼表面后,主要表现为离焦C4增加,右眼为离体(1.003 ±0.131) μm,在体(1.065 ±0.160) μm(P =0.015);左眼为离体(1.003±0.130) μm,在体1.069(0.851,1.594)μm,(P =0.017),水平/垂直散光C5变负,右眼为离体(0.072±0.083) μm,在体(-0.312 ±0.232)μm(P＜0.001);左眼为离体(0.066±0.056) μm,在体(-0.349±0.242)μm(P＜ 0.001),以及球差C12增加,右眼为离体(0.264±0.039)μm,在体(0.295±0.048) μm (P＜0.001);左眼为离体(0.266±0.035) μm,在体0.290(0.215,0.471) μm(P ＜0.001).角膜像差在戴镜前后发生改变的像差项有C4,C5,C7和C8等.在体RGPCL像差C4、C5、C12均与相应的戴镜前角膜像差呈正相关(右眼:r=0.557、0.596、0.581,P＜0.01,左眼:r=0.684、0.497、0.543,P＜0.01).结论 RGPCL戴在眼表面后,镜片前表面有一定程度的变平,球差增加,并且出现趋向于角膜的散光.RGPCL的配适不宜过于平坦.

Objective To investigate the effect of corneal irregularity on on-eye rigid gas permeable(RGP) contact lenses and the corneal shape changed by RGP contact lenses.Methods Corneal topographywas taken for 42 bare eyes of 22 subjects before and 1 month after wearing of the RGP contact lens.Off-eye and on-eye wavefront aberrations of the anterior surface of the RGP contact lens were also measured by corneal topography for the same 42 eyes.Zernike aberrations of the RGP contact lens were examined and compared to those of baseline anterior corneal surface.Results For bare eyes,C4,C5,C7 and C8 were significantly different from the baseline 30 minutes after the RGP contact lens was removed.For the on-eye RGP contact lens,three mean Zernike aberrations were significantly different from those off-eye.These were defocus C4 [OD:(1.003 ±0.131) μm off-eye and (1.065 ±0.160) μm on-eye,P=0.015; OS:(1.003±0.130) μm off-eye and 1.069 (0.851,1.594) μm on-eye,P =0.017],main axis astigmatis

背景 非球面人工晶状体(IOL)旨在降低白内障术后眼球球差,以获得更好的视觉质量.如何个性化地选择非球面IOL是尚待解决的问题.目的 对比分析白内障患者植入负球差IOL和零球差IOL后术眼波前像差及视觉质量的差异.观察角膜Q值与术后眼球球差的相关性,推测角膜Q值能否作为选择非球面IOL的参数.方法 收集年龄相关性白内障患者90例104眼,采用随机数字表法将患眼分为2个组,负球差IOL组46例52眼植入Tecnis Z9001型负球差IOL,零球差IOL组44例52眼植入Akreos AO型零球差IOL.术前测量所有患者角膜Q值,计算平均值(Q),将负球差IOL组中术前角膜Q值≤Q及＞Q的患者分别亚分为A1组25眼,A2组27眼；零球差IOL组中术前角膜Q值≤(Q)及＞(Q)的患者分别亚分为B1组29眼,B2组23跟.术后3个月检查各组患者角膜Q值,5 mm瞳孔直径下眼球球差、彗差及总高阶像差的均方根(RMS)值及暗视条件下6 mm瞳孔直径时对比敏感度(CS)及眩光对比敏感度(GS).结果 手术前与手术后角膜Q值差异无统计学意义(t=1.447,P=O.151).负球差IOL组眼球球差(0.059-±0.047) μm,低于零球差10L组(0.110±0.066) μm,差异有统计学意义(t=-4.567,P=O.000),负球差IOL组中频段、高频段CS好于零球差IOL组,差异均有统计学意义(t=2.495、2.359,P＜0.05).2个组彗差、总高阶像差差异均无统计学意义(P＞0.05).2个组患者手术前、手术后角膜Q值分别与术后眼球球差均呈弱相关(术前:r=0.277、0.292,术后:r=0.285、0.325,P＜0.05).A1与A2组,B1与B2组之间眼球球差,CS、GS间差异均无统计学意义(P＞0.05).结论 负球差IOL眼拥有比零球差IOL眼更小的球差和更好的暗视CS.角膜Q值可能不宜单独作为选择非球面IOL的参数.

Background Aspheric intraocular lens (IOL) is designed to reduce the spherical aberration of the eye after cataract surgery and to obtain better visual quality.However,the selection of a personalized aspheric IOL is a problem to be solved.Objective This study was to compare the wavefront aberration and quality of vision of patients between the implantation of negative spherical aberration IOL and non-aberration IOL,and to investigate the relationship between corneal Q values and postoperative spherical aberration.Methods One hundred and four eyes of 90 patients with age-related cataract were randomized into two groups.Fifty-two eyes of 46 patients who received a Tecnis Z9001 IOL implantation were assigned as the negative spherical aberration IOL group and 52 eyes of 44 patients who received Akreos AO IOL without aberration were assigned as the non-aberration IOL group.The preoperative corneal Q values were measured and the mean Q value(Q)was computed.Then the patients in the two groups

快速准确地从灾后影像中提取出受灾区域对于灾后救援具有重要意义。鉴于现有提取方法过度依赖滑坡在影像中的光学、纹理等特征的问题，研究了一种结合独立成分分析（ICA）与最小噪声比率变换（MNF）的变化检测方法，以单一时相的影像为基础，运用基于负熵最大化的Fast-ICA算法分离出两个时相影像相互正交的独立成分，并构建对应独立成分的差异影像，最后用最小噪声比率变换实现分布于各个差异影像上变化信息的集中，应用直方图阈值法得到了最终的滑坡灾害信息。选取了滑坡灾害前后两时相的高分辨率遥感影像数据进行实验，结果证实了方法的可行性。

It is very important for disaster relief to extract disaster information from the disaster images quickly and accurately.Given the existing methods depends on landslide disasters’texture and other information on images heavily,a new method is studied which combined the independent component analysis and the Minimum Noise Fraction Transformation.It based on the single image,separated the independent component image using the Fast-ICA algorithm of maximum neg-entropy approximations and built the components’difference images,focused the different singles which distributed all of difference images based on the MNF and got the change information by the threshold from histogram method finally.Experiment results demonstrated the method’s utility with images both be-fore and after the disaster.

目的：回顾性分析集合不足视疲劳患者的症状和体征及治疗的效果评价。方法：收集对屈光门诊诊断为集合不足型视疲劳的患者,共有40例,男23例,女17例,将上述年龄18-35岁的患者随机分为两组,每组20例,A组行笔尖训练,B组行集合调节视功能训练,12周后比较各项视功能参数。结果：两者训练方法对治疗集合不足视疲劳患者辐辏近点明显前移,正融像辐辏能力明显增强,而视功能训练组效果更为明显。同时,视功能训练还可以改善双眼调节功能,其中调节幅度、正相对调节、负相对调节、调节反应都有明显变化,从而缓解视疲劳症状,而笔尖训练组对于患者的调节功能状态没有明显改善。结论：规范的视觉训练对集合不足视疲劳具有确切疗效,而传统的笔尖训练则疗效不显著。

Objective To study the distribution of the symptoms and signs of patients with convergence insufficiency and to evaluate the effectiveness of vision therapy. Method Forty patients were recruited in our Ophthalmology department. Twenty-three of them were male, the other seventy were female. Forty patients between 18 and 35 years old who were diagnosed with convergence insufficient asthenopia were randomly divided into two groups with 20 cases in cach group. Patiens in group A were treated by pen nib training system,patients B were treated by convergence and accommodation vision function training. Their oculomotor parameters were reviewed after twelve weeks. Results The authou found that after treated,both groups,near convergence points became nearer and fusional convergence increased significant-ly. The result of vision function training were better than those of pen nib training. At the same time the accommodative function was im-proved after reasonable vision therapy,includi