掺偶氮染料聚甲基丙烯酸甲酯的介电特性研究

制备了具有不同偶氮生色团掺杂浓度的主客式聚甲基丙烯酸甲酯（PMMA）样品。利用介电测量的方法，观测了样品在532nm光照射下的介电常数和介电损耗的变化。发现随着生色团浓度的增加，样品的介电常数增大；而生色团的掺人对于聚甲基丙烯酸甲酯样品的介电损耗则主要表现在对β弛豫的影响。浓度一定的生色团样品的介电常数随着激发光功率的增加而增大；样品的高频介电损耗随着激发光功率的增大而减小，但低频直流电导损耗则随着激发光功率的增加而增大。利用生色团在光致异构反应和取向运动过程中与聚甲基丙烯酸甲酯基体的相互作用，定性地解释了上述实验现象。     

一种新型有机/无机复合非线性光学材料的制备

以含4 [乙基 (2 羟乙基)胺] 4′ 硝基偶氮苯(DR1)生色团的烷氧基硅烷染料(DR1ASD)和正硅酸乙酯(TEOS)为原料,通过溶胶 凝胶法合成了含DR1生色团的新型键合型有机/无机复合非线性光学(NLO)材料,在这种有机生色团与无机玻璃键合形成的交联网络结构中,无机玻璃的刚性三维结构和优良的高温稳定性能有效抑制NLO生色团的极化松弛。二阶谐波信号(SHG)测试表明:合成的键合型聚合物膜的二阶NLO系数(d33)值可达3.41×10-7esu;NLO稳定性也较好,在室温下放置90d,其d33值能维持初始值的94.2%;在100℃放置300min,其d33值仍能维持初始值的57.3%。     

光折变聚合物中生色团取向振荡过程的观察

利用透射椭偏技术测量了光折变聚合物PVK∶5CB∶C60中生色团5CB(4,4′-n-pentylcyanobiphenyl)的动态取向过程.当温度远高于系统的玻璃转化温度时,在很低的外加电场下就可观察到生色团5CB取向振动过程.振动频率与外加电场的大小有关.并且生色团的稳态取向分布是温度的函数.就我们所知,目前的理论模型还无法对这些现象给出合理的解释.(PH9)     

偶氮苯掺杂聚合物光致双折射的一维空间分布

报道了偶氮苯掺杂聚合物光致双折射空间分布的实验研究。发现在光照区域外较大的范嗣内有双折射，证实了生色团分子的取向运动及其引起的周边分子相互运动的存在。对3种偶氮苯染料分散红1(DR1)。分散红13(DRl3)和分散黄7(DY7)掺杂的聚甲基丙烯酸甲酯(PMMA)聚合物进行了定性研究。发现生色团分子的取向运动及其引起的周边分子相互运动与抽运光强度和生色团分子的大小等因素有关。     

基于分数阶巴特沃斯滤波器的新型超级电容器

超级电容器作为一种新型储能元件在各个领域具有广阔的应用前景。由于超级电容固有特性不是整数阶的,因此建立一个精确且适用范围更广的模型具有重要的研究意义。介绍了超级电容器的基本模型,利用分数阶巴特沃斯低通滤波器的优点,建立了一种新型超级电容器模型并验证了模型的准确性,这可以扩大超级电容器的适用范围,提高稳定性。     

电光聚合物薄膜非线性效应的研究

采用旋涂的方法制备了主客掺杂15％NAEC／PMA有机聚合物薄膜，通过测量其DSC曲线来确定玻璃化温度，并在此温度对其进行电晕极化，测量了薄膜化前后以及退化后的紫外－可见吸收光谱，研究了NAEC／PMMA薄膜中客体生色团的电极化取向以及薄膜的二阶非线性效应。     

新型有机非线性光学材料的制备及性能研究

合成了一种新型含呋喃共轭桥的有机二阶非线性光学生色团分子,用IR、1H-NMR和元素分析表征了其结构。热失重分析(TGA)结果表明,化合物的热分解温度为272℃。利用溶致变色法对材料的超极化率μβ值进行了测量,在1 064 nm激光波长下,材料的μgβ值达24 898×10-48esu。将材料作为客体掺杂于聚砜(PSU)中,用旋涂成膜法制成薄膜,对薄膜进行电晕极化后用二次谐波法(SHG)测量其二阶非线性光学系数d33,在激光基频波长为1 064 nm时,测得d33=70 pm/V。     

奥氏体化时间与冷却速率对超高碳钢组织影响的EBSD研究

本文借助EBSD技术研究了一种超高碳钢在不同奥氏体化时间和冷却速率条件下原奥氏体晶粒和珠光体团簇尺寸的变化规律。实验结果表明：原奥氏体晶粒随奥氏体化时间延长而显著增大;与传统的热蚀法相比。EBSD重构法可以获得更加准确的原奥氏体晶粒尺寸。珠光体团簇尺寸随奥氏体化保温时间延长略微增大,随冷却速率减小而明显增大;与Channel5自动截线法相比,手动截线法可获得更准确的团簇尺寸结果。     

IPC-E掺杂聚合物polysulfone薄膜电光系数的测量

制备了以生色团IPC-E为客体的掺杂型有机聚合物polysulfone薄膜样品,对其进行了接触极化。电光聚合物极化后的电光系数是聚合物波导的重要参数。利用基于简单反射法的聚合物薄膜电光系数测量系统对极化样品进行了测量,得到极化聚合物薄膜的电光系数为37pm/V左右,随后又对误差产生的原因进行了详细的分析。这为进一步研究有机聚合物光波导器件创造了条件。     

掺Eu3+聚合物光纤的团簇现象

用热聚合法制备了掺Eu(DBM)3Phen螯合物的聚合物光纤,建立了团簇化铕离子相互作用模型,以此为基础研究该掺杂聚合物光纤的团簇现象。利用速率方程理论,结合光纤的抽运光透射率实验,得到所研究光纤中团簇化铕离子浓度。掺铕质量分数为0.1%,0.2%,0.3%,0.4%,0.5%,1%的聚合物光纤中团簇化铕离子的浓度分别为0.045,0.07,0.07,0.07,0.07,0.08。因此,该掺杂聚合物光纤的团簇化铕离子浓度较低且基本不随掺杂浓度的增加而增加,铕离子之间的团簇化现象不明显。     

Synthesis of a novel organic nonlinear optical chromophore and the Testing for μgβ Value

A novel second-order nonlinear optical chromophore (DCDHF-2-V) was synthesized from 3-Hydroxy-3-methyl-2-butanae,propanedinitrile and 4-diethylaminobenzaldehyde by aldol condensation reaction. Molecular structural characterization was investigated by elemental analysis,FTIR,and 1H-NMR spectra. The melting point obtained from DSC thermogram was almost 251 ℃,and the compound shows a thermal stability up to 270 ℃. Second-order NLO properties of the chromophore were measured by solvatochromic method. From the quantum-mechanical two-level model,it can be obtained that the μgβ value of DCDHF-2-V is 6520 × 10-48 esu atthe wavelength of 1064 nm.     

Synthesis of a novel organic nonlinear optical chromophore and the Testing for μgβ Value

Much attention has been devoted to nonlinear optica (NLO) materials over the past decade because of the poten tial applications in the field of telecommunications, optica signal processing, optical switching, and so forth. Organi NLO materials with high p…     

肉桂醛衍生物的分子二阶非线性光学效应的理论研究

采用ＣＮＤＯ／Ｓ—ＣＩ方法结合引入外场的微扰理论．计算了一系列内桂醛衍生物的分子二阶极化率，并且从微观上探讨了该类化合物取代基的电子性质、取代基位置及其取代数目对分子二阶非线性光学系数的影响。结果表明，该类化合物有较高的分子二阶极化率；取代基的电子性质和取代方式对其有明显的影响。     

取代位置对香豆素衍生物二阶非线性光学性质影响的DFT研究

采用密度泛函理论（DFT）B3LYP/6-31G方法,对设计的6个不同位置取代氨基的香豆素衍生物的几何构型进行优化。在所得优化结构的基础上对这些分子的稳态二阶NLO系数β值进行计算分析,并采用含时密度泛函理论（TD-DFT）方法计算了其电子性质,研究了取代位置对香豆素类衍生物分子的二阶NLO性质的影响规律。结果表明：当氨基取代在4号位时香豆素分子中的羰基表现出供电性,对分子内电荷转移非常不利,不利于提高分子的β值;当氨基取代在在3、5、6、7、8位时分子中的羰基表现出吸电性,使分子形成D-π-A构型,并且氨基在3、7位的取代能够扩大体系的共轭范围,有效增加了香豆素分子的βtot值。     

Modeling of skin tissue ablation by nanosecond pulses from ultraviolet to near-infrared and comparison with experimental results

Comprehension of biological tissue ablation by short laser pulses in a broad optical spectrum is of fundamental importance to the understanding of laser-tissue interaction and advancing surgical applications of lasers. We report a new plasma ablation model in which the chromophore ionization pathway is incorporated to explain the skin tissue ablation by nanosecond laser pulses from ultraviolet to near-infrared. A rate equation is solved to examine the effects of chromophore, cascade, and multiphoton ionization on the optical breakdown of the tissue. The wavelength and spot size dependence of the breakdown thresholds have been measured and agreements have been found between the calculated and measured results.     

Intramolecular photo-induced electron transfer in nonlinear optical chromophores: Fullerene (C60) derivatives

The push-pull functionalized fullerenes consisting of multi-N,N-diethylamine donors covalently attached to N-methylpyrrolidine derivative of C₆₀ have been designed and investigated. The structures and first hyperpolarizabilities of these fullerene derivatives were calculated using density functional theory. Furthermore, absorption spectra of the complexes along with electron density difference maps corresponding to the most intense electronic transitions were achieved by time-dependent density functional theory. It suggests that with the growing numbers of N,N-Dimethylanilin acting as electron-donating group, the polarizabilities, dipole moments and the first hyperpolarizabilits increase, however, transition energies of the crucial electronic transitions decrease and the absorption wavelength shows bathochromic effect. The excitation transitions have significant charge transfer character and, as a consequence, the novel complexes can behave as second-order nonlinear optical chromophores, in which the N,N-Dimethylanilin act as donors towards fullerenes.     

Polarizabilities of platonic solids

This article presents results of a numerical effort to determine the dielectric polarizabilities of the five regular polyhedra: tetrahedron, cube, octahedron, dodecahedron, and icosahedron. The polarizability is calculated by solving a surface integral equation, in which the unknown potential is expanded using third-order basis functions. The resulting polarizabilities are accurate to the order of 10/sup -4/. Approximation formulas are given for the polarizabilities as functions of permittivity. Among other results, it is found that the polarizability of a regular polyhedron correlates more strongly with the number of edges than with the number of faces, vertices, or the solid angle seen from a vertex.     

Erbium-doped fiber amplifier for video distribution networks

The possibility of an application of Er-doped fiber amplifiers to AM-FDM (frequency division multiplexing) or FM-FDM video distribution networks is discussed. The measured noise and modulation distortion properties of ER-doped fiber amplifiers are good enough to meet even the severe quality standards set for trunk lines. A carrier-to-noise ratio (CNR) of 57 dB for an AM-FDM transmission was measured. A second-order harmonic distortion (HD2) of less than -56 dB was measured by the monotone method (modulation depth m=50%), and a cross modulation distortion (XM) of less than -63 dB was measured by the two-tone method (m=25%×channel). On the basis of these values, composite second-order distortion (CSO) and XM in a 40-channel transmission were estimated as less than -57 dB and -73 dB, respectively. Significant reduction of noise and modulation distortion is made possible by optimizing the length of Er-doped fiber amplifiers and using input- and output-port isolators