Investigation of the Kinetics of Curing Reaction for the Resin Matrix Polymer Composite Based on Near-Infrared Spectroscopy

Abstract

Near-infrared (NIR) spectroscopy is a rapid and nondestructive method for the simultaneous measurement of different constituents in resin matrix polymer composites. This strategy has been applied in the synthesis of resin matrix polymer composites. In this article, we mainly review the control of curing reaction kinetics of the phenolic, epoxy resin, polyester resin, polyurethane, and other polymer resin based on NIR spectra, which is important to control the quality of the resin matrix polymer composites during synthesis.     

The influence of SiCp oxidized on the interface layer and thermal conductivity of SiCp/Al composites

In this work, oxidation of silicon carbide particles (SiCp) at elevated temperature and its influence on the interface layer and thermal conductivity of SiCp/ZL101 composites prepared using pressure infiltration process were investigated respectively. It is found that initial temperature for the oxidation of SiCp is about 850?°C, and that the oxidation increment of SiCp and the thickness of SiO₂ layer increase with the increase in pre-oxidation temperature and time, when the oxidized temperature exceeds 1100?°C, or the duration time exceeds 2?h at 1100?°C, a small amount of ablation will take place on the SiCp, as well as the oxidized layer has some loss. The formation of SiO₂ layer can provide certain interface reactions with interface layers (3.1–6.36?μm), and the higher the thickness of SiO₂ layer, the thicker the interface layer in SiCp/Al composites. However, the thickness of SiO₂ layer is more than 5.9?μm, which is not benefit for the formation of interface layer. With the increase in the thickness of interface layer, thermal conductivity declines, but is not linear.     

Banana fiber/chemically functionalized polypropylene composites with in-situ fiber/matrix interfacial adhesion by Palsule process

Chemically functionalized maleic anhydride (MAH)-grafted polypropylene matrix has been used (in place of polypropylene as matrix with compatibilizer) to process banana fiber/chemically functionalized polypropylene (BF/CFPP) composites, without using any compatibilizer and without any fiber modification by Palsule process. Fiber/matrix interfacial adhesion generated, in-situ, due to interactions between BF and the MAH of the CFPP matrix has been established by Fourier transform infrared spectroscopy and scanning electron microscopy. Mechanical properties of the BF/CFPP composites developed by Palsule process with in-situ fiber/matrix interfacial adhesion in this study have been found to be higher than those of the matrix and it increases with increasing amounts of fibers in composites, and are better than properties of literature reported BF/polypropylene composites processed with compatibilizers. Measured modulus of BF/CFPP composites compares well with values predicted by rule of mixtures, Hrisch model, Halpin-Tsai equations and its modified Nielsen version, and with Palsule equation. The feasibility of developing natural fiber/MAH grafted polyolefin composites by Palsule process without using any compatibilizer and without any fiber treatment is demonstrated.     

Optical properties of polyvinyl alcohol doped (Se80Te20)100–xAgx (0 ≤ x ≤ 4) composites

Polyvinyl alcohol (PVA) doped (Se₈₀Te₂₀)_100–xAg_x (0 ≤ x ≤ 4) thin films were prepared by the spin-coating technique on a quartz substrate. The optical parameters of PVA-doped (Se₈₀Te₂₀)_100–xAg_x (0 ≤ x ≤ 4) composites at the same chalcogen concentration (S₀ = 0.1 mg ml^?1) and PVA/(Se₈₀Te₂₀)₉₆Ag₄ composites at three different chalcogen concentrations viz. S₁ = 0.3 mg ml^?1, S₂ = 0.6 mg ml^?1 and S₃ = 1 mg ml^?1 have been studied. The semi-crystalline nature of the as-deposited thin filmsisdetermined by X-ray diffraction. The transmission and reflection spectra of PVA-doped Se–Te–Ag thin films were obtained in a 350–650 nm spectral region. The optical-band gap has been calculated from the transmission and reflection data. The refractive index has been calculated by the measured reflection data. It has been found that the optical-band gap increases, but the refractive index, extinction coefficient, and the real and imaginary parts of the dielectric constant decrease, with increase in Agcontent in PVA-doped (Se₈₀Te₂₀)_100–xAg_x (0 ≤ x ≤ 4) thin films. Such type of behavior is explained on the basis of decrease in density of the defect states. However, the optical-band gap has been found to be decreased and all other optical parameters show increase in their values with increase in concentration of (Se₈₀Te₂₀)₉₆Ag₄ glass in PVA-doped composites. The results have been explained on the basis of cluster-size formation at the time of dissolution. This study shows that the optical properties of new composites are affected by the change in silver and chalcogen concentration.     

光纤混沌双芯双向保密通信系统研究

把量子阱激光混沌耦合反馈同步系统应用于光纤保密通信中,提出光纤混沌双芯双向保密通信设想.通过耦合外部光注入多量子阱激光混沌全光耦合反馈同步系统和光纤传输信道,建立了光纤混沌双芯双向通信系统物理模型.理论和数值证明了激光混沌同步,理论分析指出光纤中的自相位调制是限制激光混沌在光纤传输中同步的主要原因,并推导出混沌信号双芯双向传输中的非线性相移以及混沌激光功率限制和传输距离公式.数值实现了该系统在长距离二根光纤传输中的同步,详细地分析了系统同步时间随光纤传输长度的关系.模拟了调制频率06 GHz的混沌模拟通 关键词： 混沌 同步 光纤 保密通信     

用楔形柱面光纤微透镜耦合的1.3μm SOA组件

运用激光模式耦合理论分析了半导体光放大器(SOA)与单模通信光纤的连接损耗,并设计制作了楔形柱面光纤微透镜用来实现两者的模斑匹配,有效地降低了器件的光耦合损耗.本文介绍了楔形柱面光纤微透镜耦合的1.3 μm半导体光放大器(SOA)组件及其制作方法.该组件的最大增益不小于14 dB,其偏振灵敏度小于1 dB,增益波动不大于0.5 dB.     

窄线宽光纤激光器在1 030 nm波段实现3 kW近衍射极限输出

基于大模场面积掺镱光纤搭建了全光纤1 030 nm高功率窄线宽光纤激光主振荡功率放大系统,实现了3 004 W的最高功率输出,斜率效率69.27%,是目前报道的输出功率最高的1 030 nm波段近衍射极限光纤激光器。最高输出功率时,x,y方向的光束质量因子分别为1.169,1.174,3 dB光谱宽度为0.18 nm,放大自发辐射抑制比达到37 dB。     

基于氧化石墨烯的长周期光纤光栅的全光控制

实验验证了一种通过将氧化石墨烯分散液沉积在长周期光纤光栅的全光控制的相关研究。通过外加的垂直泵浦光的作用,氧化石墨烯吸收泵浦光产生热量,改变长周期光纤光栅的包层模式的相位差,由于热膨胀的作用改变了氧化石墨烯所覆盖部分的光栅周期,使得谐振谱发生了移动,其最大调制深度可达10.6 dB,谐振谱最大可红移12.8 nm。通过实验发现,沉积相同浓度氧化石墨烯分散液的次数影响实验结果,通过在相同光栅的相同位置分别沉积三次,发现沉积三次可以在光纤表面获得更加均匀的氧化石墨烯膜,进行了时间响应的测试,其中沉积三次后的长周期光纤光栅的响应速度可达0.61 ms,沉积多次氧化石墨烯分散液可以在光纤表面沉积得更加平整均匀,从而获得更大的导热性能。     

基于非线性光纤环形镜的少模脉冲幅度调制再生器

随着网络带宽需求的快速增加,波分复用系统的容量已接近非线性香农极限.为了适应未来网络的发展,空分复用技术引起了越来越多的关注.本文首次提出基于少模非线性光纤环形镜(FM-NOLM)的脉冲幅度调制(PAM)全光再生器,描述了其工作原理和具体设计过程.采用COMSOL软件对组成FM-NOLM的硫化物高非线性光纤进行了模式特性仿真.以LP01,LP11,LP21三个光纤模式为例,确定了再生器的参数,计算出每个模式的功率转移函数曲线.仿真分析了该少模PAM-4全光再生器的噪声抑制(NRR)性能,并与单模情形进行了比较.研究表明,1)对于每个空间模式的PAM信号,所有再生电平具有一致的功率转移性能;2)当输入信噪比(SNR)约大于20 dB时,三种模式的噪声抑制比均可超过3 dB,并随着输入信噪比线性增加,其斜率约为1.2;3)在相同输入SNR条件下,三种模式的噪声抑制比相差不大,不超过1.1 dB.为了说明再生器的再生性能,当输入SNR为25 dB时,我们还给出了再生前后PAM-4信号的功率分布直方图.与现有的再生方案相比,本文方案的均匀多电平再生转移性能,使其更适合高频谱效率的长距空分复用系统和任意电平数的PAM信号再生.此外,该方案也能够扩展到波长域,有效提高光通信系统的传输容量.     

软体操作器结构设计及植入式光纤传感方法

为解决微创手术软体机器人的形状实时监测问题,将刻有三个光纤布拉格光栅的单根光纤植入软体操作器中,利用其研究柔性硅胶软体操作器光纤传感和三维形状重构方法。进行了软体操作器的结构设计及模型建立,并对光纤光栅波长漂移量和软体操作器弯曲曲率之间的关系进行了理论分析;通过实验验证了软体操作器结构设计及其模型建立的有效性,测试了软体操作器不同弯曲状态下三个FBG传感器的反射谱特征及其变化规律;通过分析三个FBG传感器的中心波长漂移量,利用线性插值算法计算出软体操作器在不同弯曲状态下的曲率等参数,并结合曲线拟合方法实现软体操作器的三维形状重构。实验结果表明:植入式光纤光栅传感方法可以实现硅胶软体手术操作器的三维形状传感,在微创外科手术领域具有广阔的应用前景。