具有荧光发射能力有机化合物的光物理和光化学问题研究

有机化合物的结构、构象和环境效应对发光化合物的荧光发射具有重要的影响.本文从化合物激发态的衰变过程出发,侧重于过程的光化学与光物理问题对发光行为和机制进行讨论.如:化合物分子结构的受阻和桥键化对发光的影响;光激发下的光诱导电子和电荷转移及其相互转化;化合物扭曲的分子内电荷转移(TICT);溶剂分子和发光化合物分子间不同的相互作用及对发光的影响;在发光过程中存在着最佳的发光构象等.对于这些问题的研究和掌握,将有利于设计和合成具有高荧光量子产率的发光化合物,更好地解释在研究中出现的种种现象和在实际工作中应用它们.文章还引用了大量发光化合物作为实例,对工作中所得的结果进行了详细讨论.     

在表面活性剂溶液中制备不同形貌的芘纳米材料

利用水溶液中表面活性剂分子和有机小分子间的相互作用,成功地制备了具有不同形貌的芘纳米颗粒和纳米棒.对其进行吸收光谱和荧光光谱等光物理行为的研究发现,不同形貌的纳米材料展现出不同的光学性质.同时对纳米材料的形成机制做了初步的分析和讨论.     

合成方法对MCM-22分子筛的结构、性质及催化性能的影响

在水热条件下分别以动态法和静态法合成了高纯度和高结晶度的MCM-22分子筛.采用N2吸附、XRD、TEM和FTIR等方法研究了制备方法对分子筛的结构及性质的影响.结果表明,动态法合成的MCM-22比静态法合成的分子筛的晶粒小,酸量低.在丙酮一步法合成甲基异丁基酮反应中,静态条件下合成的MCM-22为载体的催化剂的丙酮转化率较高,这是由于该分子筛的酸量较高所致.而MIBK的选择性则呈相反趋势,这可能与动态条件下合成的分子筛粒径小、孔道短有关.     

在仲丁醇脱氢反应中负载型铜催化剂的研究

采用浸渍法制备Cu/SiO₂和Cu-ZnO/SiO₂催化剂.研究了活性物种Cu和助剂ZnO的担载量对催化剂的结构和性能的影响,同时考察该催化剂对仲丁醇脱氢活性和选择性的影响.借助XRD和TPR对催化剂进行了表征,结果表明,高分散的Cu⁰为反应的活性中心,ZnO起到分散和稳定铜物种的作用.铜-锌之间的某种相互作用导致了缩合产物增加.     

偏苯三酸酐-环氧丙烷丁基醚合成超支化碱溶性聚酯

通过1,2,4-偏苯三甲酸酐(TA)和环氧丙烷丁基醚(BGE)合成超支化碱溶性聚酯,利用合成聚合物分子外围的羧基与烯丙基缩水甘油醚(AGE)反应,在超支化聚合物分子外围引入反应性烯丙基醚.研究了树脂组成对感光性和碱溶性的影响;结果表明:调整反应物料配比,可以获得较好的碱溶性和光固化性能,其树脂的反差γ可达到3.92.     

Transient saturation absorption spectroscopy excited near the band gap at high excitation carrier density in GaAs

Transient saturation absorption spectroscopy in GaAs thin films was investigated using femtosecond pump and supercontinuum probe technique at excitation densities higher than 1×10^{19}cm^{-3}. The Coulomb enhancement factor of the electron－hole plasma results in a spectrum hole at the pump wavelength. Two distinct transmission peaks at two sides of the pump wavelength are observed, arising from the bleaching of transitions from the heavy- and light-hole bands to the conduction band. The dynamic process of the transient saturation absorption is fitted using a bi-exponential function. The fast decay process is dominated by the carrier-phonon scattering and the slow process may be attributed to the electron－hole recombination.     

General demonstration of principal states of polarization and real-time monitoring of polarization mode dispersion in optical fibres

We investigated the general properties of polarization effects in optical fibres and demonstrated the existence of socalled principal states of polarization (PSP), which mean the fixed points in mathematics, in different polarization effects,such as birefringence and polarization mode dispersion, by using fixed point theory. Furthermore, a time evolution vector is defined to describe the time evolution of polarization state in optical fibres, which is used to investigate the time evolution of polarization mode dispersion vector (PDV), including differential group delay and PSP. The experimental results of real-time monitoring of PDV by using this method are reported. To our knowledge, this is the first report on monitoring PSP evolution in optical fibres.     

Calculation of geometrical birefringence from two-dimensional refractive-index profile in single-mode fibres

We present two numerical approaches to calculate the geometrical birefringence from two-dimenslonal refractive-index profile in single-mode fibres. One is the improved perturbation model theory, the other is based on the general solution of noncircular uniform optical waveguide in an arbitrary coordinate system. Using these methods, we can obtain not only the magnitude of geometrical birefringence, but also the orientation of birefrlngent axes. We report the calculation results of geometrical birefringence in a real single-mode fibre.     

PmClAn基膜修饰电极的电化学及催化性质研究

聚苯胺作为电极修饰材料 ,已在传感器上显示出广泛的应用前景[1～ 4 ] .异丙醇 ( i- P)氧化[5,6 ] 是个较简单的反应 ,被广泛作为电催化研究的模型反应 .目前 ,i- P电化学氧化的研究集中于 Pt的多晶或单晶电极[7～ 9] ,Gonzales等 [10 ] 报道了 Pt- Sn共沉积的 PAn膜修饰电极上的异丙醇电氧化 ,但对复合材料的微观结构仍欠研究 .本文讨论 Pm Cl An基质性质对 Pt电沉积的影响 ,并探讨了 i- P在沉积 Pt微粒的 Pm Cl An功能膜电极上的氧化情况 .1　实验部分1 .1　电极的制备　聚间氯苯胺 ( Pm Cl An,本征态 ud,HCl掺杂态 d)采用乳液聚…     

Hawking radiation of Weyl neutrinos in a rectilinearly non—uniformly accelerating Kinnersley black hole

The quantum thermal effect of Weyl neutrinos in a rectilinearly non-uniformly accelerating Kinnersley black hole is investigated using the generalized tortoise coordinate transformation.The equations that determine the location,the Hawking temperature of the event horizon and the thermal radiation spectrum of neutrinos are derived.Our results show that the location and the temperature of the event horizon depend not only on the time but also on the angle.