共查询到20条相似文献，搜索用时 93 毫秒
1.
本文探索了利用牛顿环实验测量液体折射率的实验原理和具体的测量方法,对水的折射率进行了测量,得出了较为准确的测量结果。 相似文献
2.
3.
4.
长白山自然保护区叶面积指数测量及结果 总被引：28，自引：0，他引：28
叶面积指数（LAI）是一个重要的生物结构参数，但是大范围叶面积指数的获取比较困难。当前遥感技术为大范围叶面积指数的测量提供了条件，但遥感得到的叶面积指数需要进一步的地面验证。因此实地叶面积指数的获得具有重要意义。叶面积指数实地测量方法包括直接测量方法和间接光学测量方法，由于直接测量方法具有局限性，而光学测量方法中集聚效应又很重要，该研究采用了考虑集聚效应的光学测量方法，通过观测和计算，长白山自然保护区主要植被类型的叶面积指数分别是：红松阔叶林7.7，云冷杉林6.6，阔叶林3.9，岳桦林3.4。在测量结果的基础上，分析了不同植被类型的叶面积指数的分布情况。通过对实际叶面积指数和有效叶面积指数的比较和分析，发现集聚效应对于使用光学测量方法测量叶面积指数有重要影响。 相似文献
5.
不同阻抗连接方法不同，其测量方法也不同，本文主要介绍了电感器、电容器和交流电阻器的测量方法及屏蔽技术在测量中的应用。 相似文献
6.
分光计测量折射率探讨 总被引：1，自引：0，他引：1
分光计是大学物理中测量折射率的主要仪器,且测量角度精度较高。本文尝试了在分光计上利用布儒斯特角法测量玻璃砖、四硼酸钠、硫酸铝、冰的折射率,并分别其物体的折射率理论值相对比,结果显示,相对误差不超过8%。 相似文献
7.
折射率是透明固体的一个重要参数,折射率能在一定程度上反应了质的性能及成分。在类透明固体产品的生产过程中,实时而准确的测量折射率参数是其质量的重要保证,其中最为常见的就是玻璃折射率测量。传统的玻璃折射率测量一般采用插针法、掠入法,或者用迈克尔逊干涉仪等方法进行测量,但这些方法具有主观性,测量过程相对复杂,测量精度普遍不高。因此本文的研究侧重点为基于V棱镜法对玻璃的折射率进行测量。 相似文献
8.
9.
10.
11.
This letter reports the development of an optofluidic Fabry–Pérot (FP) resonator, which consists of a microcavity and a pair of liquid microlenses. The microcavity forms part of the microchannel to facilitate sample injection. The liquid microlenses are used for efficient light coupling from the optical fiber to the microcavity. The liquid microlens collimates the diverging light from the optical fiber into the FP cavity, which provides real-time tuning to obtain the highest possible finesse up to 18.79. In volume refractive index measurement, a sensitivity of 960 nm per refractive index unit (RIU) and a detection range of 0.043 RIU are achieved. 相似文献
12.
闪锌矿型CdTe电子结构和光学性质的第一性原理 总被引：4，自引：0，他引：4
采用基于密度泛函理论(DFT)框架下广义梯度近似平面波超软赝势法,计算了闪锌矿型CdTe的能带结构、态密度和光学性质.计算表明,闪锌矿型CdTe为直接带隙半导体,禁带宽度为0.671eV.计算并分析了闪锌矿型CdTe的复折射率、复介电函数、吸收系数、光电导率、损失函数和反射率,其折射率为2.69,静态介电常数为7.23.计算结果与其他文献结果吻合较好,为闪锌矿型CdTe的应用提供了理论依据. 相似文献
13.
在光学系统中,SOI(绝缘体上的半导体)上制备集成的MMI(多模干涉)型光耦合器已成为一种愈来愈引人注目的无源器件.由于Si和SiO2 之间具有大的折射率差,在SOI波导中可以采用SiO2 薄膜( <1.0 μm)作限制层,这与超大规模集成电路工艺相兼容.描述了采用SOI技术制备集成的MMI型光耦合器和光开关的设计和制造结果.业已证实,2× 2MMI MZI(多模干涉 麦赫 曾德干涉)型热光开关的开关时间小于 2 0 μs. 相似文献
14.
目前的宽视角的接收一般采用视角分割,以使用多探测器或者复杂接收系统(如光纤阵列)等方式获得,但以上方式主要用于光电对抗的方位探测,在空间激光通信等场合难以适用。基于空间激光通信领域,结合目前宽视角光学接收天线的研究和进展情况,比较分析了现有的技术后,综合考虑视角、光学增益及像差大小,提出一种系统的新思路,针对宽视角、大口径接收面积的指标需求,以小接收面积光电探测器、阵列化天线为约束前提,力争结构简单、经济合理,为后续的深入研究打下良好的基础。 相似文献
15.
This paper presents the design and analysis of a liquid refractive index sensor that utilizes a unique physical mechanism of resonant optical tunneling effect (ROTE). The sensor consists of two hemicylindrical prisms, two air gaps, and a microfluidic channel. All parts can be microfabricated using an optical resin NOA81. Theoretical study shows that this ROTE sensor has extremely sharp transmission peak and achieves a sensitivity of 760 nm∕refractive index unit (RIU) and a detectivity of 85 000 RIU−1. Although the sensitivity is smaller than that of a typical surface plasmon resonance (SPR) sensor (3200 nm∕RIU) and is comparable to a 95% reflectivity Fabry–Pérot (FP) etalon (440 nm∕RIU), the detectivity is 17 000 times larger than that of the SPR sensor and 85 times larger than that of the FP etalon. Such ROTE sensor could potentially achieve an ultrahigh sensitivity of 10−9 RIU, two orders higher than the best results of current methods. 相似文献
16.
Guoyin Chen Gang Wang Xinrong Tan Kai Hou Qingshuo Meng Peng Zhao Shun Wang Jiayi Zhang Zhan Zhou Tao Chen Yanhua Cheng Benjamin S Hsiao Elsa Reichmanis Meifang Zhu 《国家科学评论(英文版)》2021,8(9)
Hydrogel optical light-guides have received substantial interest for applications such as deep-tissue biosensors, optogenetic stimulation and photomedicine due to their biocompatibility, (micro)structure control and tissue-like Young''s modulus. However, despite recent developments, large-scale fabrication with a continuous synthetic methodology, which could produce core-sheath hydrogel fibers with the desired optical and mechanical properties suitable for deep-tissue applications, has yet to be achieved. In this study, we report a versatile concept of integrated light-triggered dynamic wet spinning capable of continuously producing core-sheath hydrogel optical fibers with tunable fiber diameters, and mechanical and optical propagation properties. Furthermore, this concept also exhibited versatility for various kinds of core-sheath functional fibers. The wet spinning synthetic procedure and fabrication process were optimized with the rational design of the core/sheath material interface compatibility [core = poly(ethylene glycol diacrylate-co-acrylamide); sheath = Ca-alginate], optical transparency, refractive index and spinning solution viscosity. The resulting hydrogel optical fibers exhibited desirable low optical attenuation (0.18 ± 0.01 dB cm−1 with 650 nm laser light), excellent biocompatibility and tissue-like Young''s modulus (<2.60 MPa). The optical waveguide hydrogel fibers were successfully employed for deep-tissue cancer therapy and brain optogenetic stimulation, confirming that they could serve as an efficient versatile tool for diverse deep-tissue therapy and brain optogenetic applications. 相似文献
17.
一维光子晶体传输矩阵法的分析改进 总被引：2，自引：0，他引：2
为了更准确地分析一维光子晶体的光子禁带特性和研究改善光子晶体性能的方法,通过在传输矩阵法的推导过程中加入了多重反射的概念和修正了传输矩阵的相位项,改进了用传输矩阵分析一维光子晶体禁带特性的方法,提高了计算精确度,结合理论仿真数据与实验测量值的对比证明了该改进算法的有效性,尤其是在非垂直入射的情况下,改进算法与实验数据符合良好。另外还探讨了组成光子晶体膜层的高低折射率介质的折射率比值,光学厚度,周期数等参数对光子禁带特性的影响,并提出了通过选用合适的光学厚度和周期数,采用新型材料,引入多缺陷态结构等改进一维光子晶体禁带特性的初步设想。 相似文献
18.
Laura Campo-Dea?o Roel P. A. Dullens Dirk G. A. L. Aarts Fernando T. Pinho Mónica S. N. Oliveira 《Biomicrofluidics》2013,7(3)
The non-Newtonian properties of blood are of great importance since they are closely related with incident cardiovascular diseases. A good understanding of the hemodynamics through the main vessels of the human circulatory system is thus fundamental in the detection and especially in the treatment of these diseases. Very often such studies take place in vitro for convenience and better flow control and these generally require blood analogue solutions that not only adequately mimic the viscoelastic properties of blood but also minimize undesirable optical distortions arising from vessel curvature that could interfere in flow visualizations or particle image velocimetry measurements. In this work, we present the viscoelastic moduli of whole human blood obtained by means of passive microrheology experiments. These results and existing shear and extensional rheological data for whole human blood in the literature enabled us to develop solutions with rheological behavior analogous to real whole blood and with a refractive index suited for PDMS (polydymethylsiloxane) micro- and milli-channels. In addition, these blood analogues can be modified in order to obtain a larger range of refractive indices from 1.38 to 1.43 to match the refractive index of several materials other than PDMS. 相似文献
19.
We present experimental demonstrations of optical manipulation and optical binding of microscopic glass rods using the multiple traps created by a dual-fiber optical trapping system. Trapping, alignment, rotation, and stacking of glass rods were realized. To the best of our knowledge, this is the first time that cylindrical particles are optically trapped and bound by an optical fiber-based system. The optical manipulation of rods is also investigated through numerical simulations, which are used to quantitatively explain the experimental results. The ability of manipulating multiple particles of different shapes, as well as the integrable nature of the fiber-based setup, bestows the system the potential to be used in microfluidic systems for versatile particle manipulations. 相似文献
20.
光突发交换是一种介于光路交换和光分组交换之间的很有发展潜力的交换模式,它结合了两者的优势又克服了两者的缺点。本文重点阐述了光突发交换的概念、特点和关键技术,并介绍了光突发交换目前的研究状况和应用前景。 相似文献