全媒体演播室的功能定位与技术策略

在媒体融合趋势下,传统演播室技术平台已经难以适应全媒体节目的应用需求.运用互联网思维,围绕去中心化、用户思维和互动直播,明确了全媒体演播室的功能定位,提出了以敏捷服务为特征的全媒体演播室技术策略.为电视媒体与新媒体转型融合提供了一种新的尝试.     

反射式光学中心偏自动测量方法

本文简述了中心偏产生的原理,介绍了采用反射式自准直原理设计的一个调焦全自动、被测透镜自动旋转的中心偏自动测量系统。     

物链网综述:区块链在物联网中的应用

物联网设备数量的激增和中心化的管理架构给物联网的发展带来了严峻的挑战，区块链技术的去中心化和不可篡改等特点可以用来解决物联网的上述难题，故此将区块链技术应用到物联网领域成为研究热点。随着区块链技术在物联网应用中的深入研究，出现了一个新的概念："物链网"。本文首先介绍了物联网的行业痛点和区块链相关技术，然后分析了将区块链技术应用到物联网领域的论文和白皮书，把融合文献分为平台架构和应用场景两类后，进行归纳总结，并调研了应用领域的典型公链和商业项目，指出了将区块链技术应用于物联网领域所面临的挑战与机遇，讨论了相应的解决方案，最后展望了"物链网"未来的发展趋势，提出未来研究方向应侧重于数据存储和数据管理方向。     

综合验光仪中镜片偏心与倾斜对验光的影响分析

利用几何光学和眼科屈光学基本原理,针对综合验光仪加工和装配中的两项主要误差:镜片偏心和倾斜给验光带来的影响进行了分析,并用ZEMAX软件进行验证.结果表明综合验光仪中的镜片若存在偏心,则会在验光中引入棱镜度误差,该误差与镜片的屈光度数和偏心量有关;若镜片存在倾斜,则不但会引起轴向主光线在像方焦面上像点位置的偏移,即棱镜度误差,还会给验光引入球镜度和柱镜度误差,其中柱镜度误差是球镜度误差的2n倍,并且镜片两表面发生反向倾斜给验光带来的影响要比装配时镜片整体倾斜的影响显著.此外,镜片装配时由于偏心给验光带来的影响要比倾斜大,所以在综合验光仪的加工或装配过程中应严格控制镜片偏心和两表面反向倾斜.     

Scleral lens centration: The influence of centre thickness,scleral topography,and apical clearance

PurposeTo investigate the effect of lens centre thickness (and mass) upon short-term horizontal and vertical scleral lens decentration, and the association between both scleral topography and apical clearance, with lens decentration.MethodsLens decentration was measured using over-topography data from 9 healthy young participants (25 ± 4 years) with normal corneae fitted with ICD 16.5 scleral lenses (hexafocon B material) with centre thicknesses of 150, 250, and 350 μm, while controlling for other lens parameters. Scleral toricity and elevation were determined from sagittal height data over a 15 mm chord obtained from a corneo-scleral topographer and central apical clearance was quantified using anterior segment optical coherence tomography.ResultsThe mean lens decentration was 0.55 ± 0.19 mm temporally and 0.84 ± 0.35 mm inferiorly, which did not vary significantly with centre thickness (p > 0.05). The mean nasal-temporal asymmetry in scleral elevation data was substantially greater (619 ± 67 μm) compared to the vertical meridian (369 ± 57 μm) (p < 0.01), and this variation in scleral topography along the horizontal meridian was associated with the magnitude of horizontal lens decentration (r = 0.68, p = 0.04). Greater initial central apical clearance was associated with more inferior lens decentration (r = −0.78, p = 0.01).ConclusionLens centre thickness and mass did not significantly influence centration. Horizontal lens decentration was associated with the nasal-temporal asymmetry in scleral elevation, while vertical lens decentration correlated with initial central apical clearance. Factors affecting scleral lens centration may vary between the horizontal and vertical meridians.