TG-FTIR技术对水氯镁石结晶热解过程的研究

水氯镁石脱水是镁资源利用的关键.其中一种重要的方法是向水氯镁石中添加助剂形成复盐及络合物脱水.通过缓慢冷却水氯镁石及盐酸苯胺的过饱和水溶液制备了水氯镁石-盐酸苯胺结晶物.通过TGDTA-FTIR联用技术分析了盐酸苯胺、水氯镁石以及盐酸苯胺-水氯镁石结晶物的热解过程,定性检测每步分解的逸出气体以推测反应过程.结果显示:盐酸苯胺在400℃以前仅发生物理变化;水氯镁石的热解分阶段进行,205℃以前发生脱去四个结晶水,205℃以后在脱水反应的同时发生水解反应生成HCl;盐酸苯胺-水氯镁石结晶物分阶段脱水、脱盐酸苯胺,整个过程没有水解现象发生,能够得到高纯度无水氯化镁.     

Optical investigation of cavitation erosion by laser-induced bubble collapse

By means of a new force sensor based on optical beam deflection (OBD), the mechanical effects of laser-matter interaction underwater at different incident laser energy are investigated in detail. The experimental results show that a target underwater is impacted in turn by laser-plasma ablation force and high-speed liquid-jet impulse induced by bubbles collapse in the vicinity of a solid boundary. Furthermore, the amplitudes of the two forces increase monotonously with laser energy. According to the ablation force detected by the experiment and the theoretical relationship between laser intensity and ablation pressure, the value of liquid-jet impact against a solid boundary can be easily obtained. In addition, based on the model of a collapsing bubble, some characteristic parameters, such as the liquid-jet impact velocity, the maximum bubble radius, the bubble energy can also be obtained at different laser energy, which are valuable in the corresponding research fields.     

355 nm激光作用下苯甲醚的多光子电离质谱研究

在355 nm激光作用下,利用多光子电离技术结合飞行时间质谱(TOF-MS)对苯甲醚分子进行了研究。实验结果表明苯甲醚分子的多光子电离机制属于母体分子电离-解离模型。通过对主要碎片离子的可能形成过程的讨论,得出该波长下母体分子离子解离的主要有两种通道,但是随激光能量的增强,甲基移除通道逐步占据优势成为主要通道。应用高斯软件采用HF/6-31G(d) 方法对苯甲醚分子和苯甲醚阳离子基态的几何构型进行优化得到其稳定构型,并计算了苯甲醚分子离子及其初级解离产物的能量。比较两条通道的碎片离子能量的变化,理论验证了实验中苯甲醚分子主要解离通道的合理性。     

一种双正则项全变差高光谱图像去噪算法

受传感器特性影响,高光谱图像中的噪声在各个维度都有体现。噪声的存在降低了高光谱图像中信息的有效性,在进行地物分类前必须采用适当的算法对噪声予以去除。文章针对高光谱图像的噪声特性,提出了一种基于全变差的高光谱图像去噪算法。该算法将经典二维图像全变差去噪模型推广至三维形式,提出了采用双正则项及相应的调整参数的目标函数,在三维空间中完成新目标函数的离散化,并采用基于优化-最小化算法的迭代方法对目标函数进行优化与求解。对星载Hyperion成像光谱仪数据的实验表明,适当的设置调整参数,该方法可很好地提高高光谱图像的各波段信噪比、平滑光谱曲线并保留细节特征,其去噪效果优于经典的MNF去噪算法及Savitzky-Golay滤波方法。     

Sixtieth order harmonic mixing to 4.25 THz using a Schottky diode

Harmonic mixing of mm-waves with radiation of 3.7 THz with different Schottky diodes is reported. The highest mixing order is 60 producing a beat between 72 GHz and 4.25 THz radiation. Such high frequency mixing has so far only been possible using cryogenic Josephson mixers. The present result permits substantial simplification of measurements of optical frequencies.     

Structural polarization properties of vector Gaussian beam in the far field

Based on the vector angular spectrum representation of optical beam and the method of stationary phase, the analytical TE and TM terms of vector Gaussian beam have been presented in the far field. By using the local polarization matrix, the polarization properties of the TE and TM terms in the far field are investigated, and it is found that the degree of their polarization is only determined by the spatial location. When the source is completely polarized, the TE and TM terms are both completely polarized in the far field. When the source is completely unpolarized, the TE and TM terms in the far field are partially polarized. The whole beam is also partially polarized except on the propagating axis. Moreover, the degrees of polarization of TE and TM terms are both larger than that of the whole beam.[第一段]     

CdTe/CdO nH2O核壳纳米复合粒子的水相合成及光学特性.

"研究了CdTe/CdO?nH2O核壳纳米复合物的水相合成及其光学特性． 以巯基乙酸为稳定剂通过氯化镉和碲氢化钠反应制备了碲化镉纳米晶． 在反应过程中, 反应前驱溶液中镉离子与碲离子的摩尔浓度比对最终制备的碲化镉纳米晶的荧光强度起到了极其重要的作用． 在pH值为8.2, 镉离子与碲离子摩尔浓度比为4.0的情况下,制备出了具有最强荧光强度的碲化镉量子点．之后,CdTe/CdO?nH2O核壳纳米复合物在水相中制备出来．在适当的氢氧化镉沉积在碲化镉纳米粒子表面后,碲化镉量子点的荧光大大增强．所制备的CdTe/C     

Pitchfork bifurcation and circuit implementation of a novel Chen hyper-chaotic system

In this paper, a novel four dimensional hyper-chaotic system is coined based on the Chen system, which contains two quadratic terms and five system parameters. The proposed system can generate a hyper-chaotic attractor in wide parameters regions. By using the center manifold theorem and the local bifurcation theory, a pitchfork bifurcation is demonstrated to arise at the zero equilibrium point. Numerical analysis demonstrates that the hyper-chaotic system can generate complex dynamical behaviors, e.g., a direct transition from quasi-periodic behavior to hyper-chaotic behavior. Finally, an electronic circuit is designed to implement the hyper-chaotic system, the experimental results are consist with the numerical simulations, which verifies the existence of the hyper-chaotic attractor. Due to the complex dynamic behaviors, this new hyper-chaotic system is useful in the secure communication.     

受激布里渊散射对激光在水中衰减特性的影响

测量了不同能量的光束，通过不同长度的水介质在窄线宽与宽线宽两种情况下的衰减系数，研究了受激布里渊散射对激光在水中衰减特性的影响.结果发现，激光光束在水中传播时的衰减系数与激光光强和线宽有关，而不是通常情况下所认为的常数.还从理论上进行了分析.