共查询到20条相似文献,搜索用时 281 毫秒
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了降低聚合物/液晶光栅的散射损失,并消除光栅的偏振依赖性,选取了低官能度的光敏单体作为反应体系,并逐步提高光栅的制备温度。首先选用五官能度的DPHPA (dipentaerythritol hydroxyl pentaacrylate)、双官能度的PDDA( phthalic diglycol diacrylate)以及单官能度的NVP (N-vinylpyrrolidone)作为反应体系;其次,在制备过程中在光栅的后面放置加热台,逐步提升制备温度。实验结果表明:当制备温度上升到62 ℃以上,光栅有更多(36%)的液晶析出,相分离比常温下制备时要更完全一些,而且高温下制备的光栅其平整度更高,从而使光栅的散射损失比常温下减小了66.7%,器件的SEM图片也进一步证明了这个结论。同时高温制备也消除了液晶光栅的偏振依赖特性。 相似文献
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熊猫型保偏光纤光栅温度和压力传感特性的实验研究 总被引:1,自引:1,他引:1
对熊猫型保偏光纤光栅的传感特性进行了深入的实验研究,采用温箱和压力罐分别进行了温度和压力传感特性的实验研究.实验结果表明:在0~2.5 MPa的压强范围内,熊猫型保偏光纤光栅两个偏振方向上的压力敏感系数分别为0.004 88 nm/MPa和0.003 52 nm/MPa;在15~50 ℃的温度范围内,两个偏振方向上的温度敏感系数为0.01018 nm/℃和0.008 8 nm/℃.该光纤光栅两偏振态对温度和压力的不同敏感特性可用于解决光纤光栅的交叉敏感问题. 相似文献
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《物理学报》2016,(20)
本文对光子晶体光纤重叠光栅的传输光谱及特性进行了研究.在理论上,提出了基于V-I传输矩阵法的光子晶体光纤重叠光栅分析模型,仿真研究了布拉格叠栅和啁啾叠栅的反射谱和时延特性.在实验上,利用193 nm紫外激光在光敏单模光子晶体光纤中实验制备了定制波长间隔的四重布拉格重叠光栅和波长间隔0.82 nm的啁啾重叠光栅.研究结果显示布拉格光栅的重叠光栅可通过各子光栅写制参数实现光谱灵活定制;基于啁啾光栅的重叠光栅具有周期性宽带滤波特性,谐振周期可由光栅周期偏移调整,且具有平坦的幅度响应和呈良好线性的群时延.实验所得光栅光谱与理论分析很好地符合.研究结果为光子晶体光纤重叠光栅的设计、制备及应用提供了重要的参考依据. 相似文献
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纳米银掺杂的高效率全息聚合物分散液晶光栅制备 总被引:3,自引:0,他引:3
报道了一种基于掺杂纳米银聚合物分散液晶(PDLC)材料的高衍射率全息电控光栅的制备及特性。通过在原有聚合物分散液晶材料体系中添加适量的纳米银颗粒以制备体全息光栅,实验研究了掺杂不同质量比的纳米银颗粒对全息聚合物分散液晶(H-PDLC)体光栅的衍射效率、驱动阈值电压、响应时间的影响。实验结果表明,通过掺杂纳米银材料,能够优化聚合物和液晶两相分离结构,使聚合物与液晶分离更加彻底,显著提高H-PDLC体光栅的一级衍射效率,同时能改善体光栅的电光特性,缩短响应时间。初步分析表明,由于纳米银颗粒的表面等离子体效应和体系折射率匹配的优化改善了H-PDLC光栅的特性。 相似文献
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Different intermittent curing methods were conducted for pulsed laser induced photopolymerization reactions in a TMPTA acrylic
system. Two methods of curing were compared, named grouped pulses impingement (GPI) and consecutively pulsed curing (CPC),
respectively, in which the total number of the curing pulses were kept same. In GPI, a prominent light diffraction effect
was observed in the post curing process, but was absent in the CPC procedure. A condensed but limited sized core of polymeric
structure was the cause of the light diffraction. The amount of inhomogeneity in the refractive index for the core was about
90% of the cured background. Simulations based on Fresnel diffraction theory were performed, and the result was in good agreement
with the experimental observations.
PACS 42.25.Bs; 61.82.Pv; 82.35.-x 相似文献
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Rubber magnetic composites were prepared by incorporation of strontium ferrite into natural rubber-based continuous matrix. The prepared rubber compounds have model character and besides the rubber and the filler, they contained only ingredients of peroxide curing system, dicumyl peroxide as curing agent, and ethylene glycol dimethacrylate as co-agent. The work was focused on the evaluation of curing system composition and magnetic filler content on curing process, cross-link density, physical–mechanical and magnetic properties of tested materials. The achieved results revealed that the evaluated properties are dependent on the composition of curing system and on the content of ferrite too. Ferrite incorporated in the rubber matrix imparts magnetic properties to the composites considerably. In addition, the improvement of physical–mechanical properties with doping content of ferrite was observed. 相似文献
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小孔阵列衍射特性与应用 总被引:5,自引:4,他引:1
以单色标量波衍射理论为基础,研究了均匀平面波从不同角度入射小孔阵列的衍射特性。运用单孔衍射理论,同时考虑相邻小孔间衍射光强的相互影响,建立了小孔阵列衍射的理论模型和光强分布的数值积分式,小孔为硬边小孔。利用Matlab对500 nm波长的平面波入射微小方孔阵列衍射图样进行了计算机仿真,得到了不同几何参量下平面波从不同角度入射时的衍射图样的一维和二维光强分布图,并将仿真结果用于微型数字式太阳敏感器的光学系统中的结构参量设计和图像处理中的参量确定。太阳敏感器的成像实验结果表明,小孔阵列衍射光强分布图的仿真结果正确、太阳敏感器光学系统参量设计合理。小孔阵列衍射理论为太阳敏感器的光学系统设计和图像处理提供了可靠的理论基础。 相似文献
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We report on the experimental observation of two-wave mixing that occurs inside a sample between the beams used for the fabrication of polymer-liquid-crystal-polymer slices (POLICRYPS) diffraction gratings. The effect depends on the phase shift between the curing interference pattern and the grating being cured. This shift can be mechanically induced by accidental vibrations of the experimental setup; thus a high setup stability is needed. We devised a mechanism that enables us to control setup vibrations in situ and used it to monitor the experiment. When the mechanically induced shift was significantly small, wave mixing was observed only if the initial intensities of the two curing beams were different from each other. 相似文献
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针对UV LED固化系统行业存在的调试、升级频繁导致的维护及人员成本突出的问题,提出了一种支持断点续传的UV LED固化系统远程升级方法。利用基于STM32系统的IAP技术配合改良的远程升级程序代替传统J-LINK的调试烧写,节约了调试人员奔赴现场调试的时间和成本。由于远程传输必然有一定的误码率,而利用断点续传技术可以大幅缩减使用GPRS等作为远程传输模块时的流量消耗;考虑到固化系统的安全性,提出利用分包计算CRC和设置备用程序存储区域的方法加强了升级系统的可靠性。实验结果验证了该方法应用于UV LED固化系统远程调试升级的可行性及安全性,并且可以大幅缩减远程通信的流量,这在一定程度上提高了升级系统的安全性。 相似文献
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M. W?odarska B. Mossety-Leszczak G. W. B?k H. Galina R. Ledzion 《Opto-Electronics Review》2009,17(2):105-111
The paper presents research results on curing two recently synthesized liquid crystalline epoxy materials with selected amines.
The process of cross-linking, the final product of curing, and the pure monomers were examined using polarizing optical microscopy
(POM), differential scanning calorimetry (DSC), and dielectric spectroscopy (DS). Chemical structure of the products was confirmed
using spectroscopic methods. The authors attempted to demonstrate how selection of curing conditions (such as the amine used
as curing agent, the curing temperature or preparation of the surface in contact with the sample) influences optical properties
of the cured product. 相似文献
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With the rapid development of automobile, aviation, aerospace, machinery and other fields, rubber products used in these fields required to meet higher requirements. Fluorine rubber (FKM) and silicone rubber (MVQ) have excellent performance in some areas. However, the FKM is poor in low-temperature resistance and processing performance, limiting its applicability. Although the MVQ has a wide range of temperature and excellent processing performance, but its mechanical properties and oil resistance are not good. In this work, the MVQ/FKM blends were prepared by two different mechanical blending methods. The effects of the mixing process, mass ratio, curing system and conditions of the blends were studied. The chemical compositions of the blends were analyzed by infrared spectroscopy (IR). The compatibility and the thermal properties of the blends were investigated by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. The results showed that the mechanical properties, compatibility and thermal stability of the blends were the best when they were prepared by kneading the FKM and MVQ individually in a two-rool mill roll, then mixing them together homegeneously with an MVQ/FKM mass ratio of 10/90, curing system of (4 phr, 1/9) dicumyl peroxide (DCP)/N, N-Dicinnamylidene-1, 6-hexanediamine (3# Vulcanizer), first curing conditions at 170?°C under 10?MPa for 30?min and post curing conditions at 200?°C for 6?hours at 1 atmospheric pressure. 相似文献
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采用二官能度环氧树脂对己二胺进行改性,得到了含多段长亚甲基链段的柔性固化剂。利用红外光谱表征其基本结构。采用环氧树脂E-44与之进行固化,通过不同温度下固化时间对力学强度影响的分析,初步确定其最佳固化条件为80 ℃,6 h。通过热重分析检测不同固化比例下固化产物的热稳定性,并采用差示扫描量热法研究该固化剂的固化动力学参数、反应活性、最佳固化温度及时间。对其固化物拉伸剪切强度进行测试,测试结果表明:在固化比例为1:0.5时,在-196 ℃、室温、60 ℃下的拉伸剪切强度分别为16.84,14.73和13.52 MPa,基本满足实际应用的需求。 相似文献
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基于养护龄期的煅烧煤矸石细集料砂浆X射线衍射及扫描电镜分析 总被引:1,自引:0,他引:1
采用X射线衍射法(XRD)和环境扫描电镜(SEM)分析方法,研究了不同煅烧温度下煤矸石细集料的活性,针对活性最高的700 ℃高温煅烧煤矸石细集料砂浆的水化产物、微观结构和强度进行了探讨,并分析了砂浆强度随养护龄期(3,7,14,28,60和90 d)增长的变化规律。试验研究表明:煤矸石细集料随着煅烧温度的升高,其活性逐步增加,当煅烧温度达到700 ℃左右时,煤矸石细集料的活性达到最高,当煅烧温度继续升高时,活性呈下降趋势。经过700 ℃高温煅烧的煤矸石细集料具有明显的火山灰活性,其活性组分SiO2和Al2O3能与水泥水化产物发生一定程度的二次水化反应,通过对不同养护龄期的活性最高的700 ℃高温煅烧煤矸石细集料砂浆XRD和SEM分析可知,随着养护龄期的增长,二次水化反应将更加充分,而且水化产物的数量也逐步增多,与早龄期的水泥砂浆相比,生成物相更为稳定的水化产物填充在砂浆的微观孔隙中,能够进一步改善砂浆的微观结构,增强砂浆的界面性能,使砂浆内部结构更加均匀,煅烧的煤矸石细集料和水泥砂浆更趋为一个坚固连续的整体,水泥硬化砂浆的后期强度有较大增幅,活性最高的700 ℃高温煅烧煤矸石细集料火山灰效应明显。 相似文献
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d'Alessandro A Asquini R Gizzi C Caputo R Umeton C Veltri A Sukhov AV 《Optics letters》2004,29(12):1405-1407
We report the diffraction properties at wavelengths of 632.8 and 1550 nm for volume transmission gratings made of a sequence of continuously aligned nematic liquid-crystal layers separated by isotropic polymer slices. The gratings are generated by holographically curing a solution of liquid crystal diluted in an isotropic prepolymer by means of a laser beam at a wavelength of 352 nm with a total intensity of approximately 10 mW/cm2. A diffraction efficiency of 98% was measured, and an electric field as low as 5 V/microm switches off the phase grating. Measured angular spectra are fitted by use of the modified coupled-mode theory including the effects of grating birefringence. 相似文献