快速发光二极管的性能与分析

本文叙述了用于光通信快速、高辐射度GaAs/GaAlAs双异质结发光管的性能.其电带宽大于60MHz,光带宽在100MHz以上.在200mA辐射度为1017W/cm2·sr.尾纤输出超过160μw(NA=0.2).分析和讨论了影响辐射输出和调制能力的诸因素,并选取了最佳折衷方案.     

The Cauchy problem for non-autonomous nonlinear Schrödinger equations

In this paper we study the Cauchy problem for cubic nonlinear Schrödinger equation with space- and time-dependent coefficients on ∝^m and \(\mathbb{T}^m \). By an approximation argument we prove that for suitable initial values, the Cauchy problem admits unique local solutions. Global existence is discussed in the cases of m = 1, 2.     

含钛MCM-48分子筛上二十碳醇氧化制二十碳酸

采用水热合成法制备含钛ＭＣＭ－４８型中孔分子筛系列催化剂，用ＩＲ和ＸＲＤ等技术对催化剂进行了表征，对α－二十碳醇氧化制α－二十碳酸反应进行了研究，对目的反应的催化性能进行了评价，并确定出反应的最佳温度和反应时间，结果表明，添加适量的Ｔｉ可提高α－二十碳酸的收率。用ＩＲ技术对目的产物进行跟踪分析，所得结果与化学检测结果一致，将反应产物的收率与分子筛催化剂的Ｌ酸进行了关联。     

Biocompatible Micelles Based on Comb‐like PEG Derivates: Formation,Characterization, and Photo‐responsiveness

A novel comb‐like derivative CPEG‐g‐DNQ was prepared by incorporating light responsive 2‐diazo‐1,2‐naphthoquinone (DNQ) groups into the structure of comb‐like poly(ethylene glycol) (CPEG). DLS and TEM results showed that CPEG‐g‐DNQ self‐assembled into spherical micelles with an average size of about 135 nm in water. Upon exposure to light, the micelles could be disrupted because of the conversion of hydrophobic DNQ to hydrophilic 3‐indenecarboylic acid. Additionally, hydrophobic coumarin 102 was successfully loaded into the micelles and photo‐induced ON‐OFF release was demonstrated by fluorescence spectroscopy. MTT assay revealed that the micelles are biocompatible. These photo‐responsive micelles might have great potential for controlled release of hydrophobic drugs.

     

A study of optical properties of a four-level atomic system via vacuum-induced coherence effects

This paper studies the effects of vacuum-induced coherence(VIC) in a four-level atomic system.The effects of VIC lead to the coherent hole burnings exhibited in the system at some certain points of the Rabi frequency.This is also the reason for the enhancement of the coherent population trapping.In addition,optical bistability occurs in the evolution curves of absorption versus the phase of Rabi frequencies.     

A highly sensitive fluorescent immunoassay based on avidin-labeled nanocrystals

Nanocrystals of the fluorogenic precursor fluorescein diacetate (FDA) were applied as labels in order to improve on the assay sensitivity achieved in our previous studies. Each FDA nanocrystal can be converted into ∼2.6×10⁶ fluorescein molecules, which is useful for improving immunoassay sensitivity and limits of detection. NeutrAvidin was simply adsorbed onto the surface of the FDA nanocrystals, which were coated with distearoylglycerophosphoethanolamine (DSPE) modified with amino(poly(ethylene glycol))(PEG(2000)-Amine) as an interface for coupling biomolecules. This can be applied to detect different kinds of analytes that are captured by corresponding biotinylated biomolecules in different bioanalytical applications. The applicability of the NeutrAvidin-labeled nanocrystals was demonstrated in an immunoassay using the labeled avidin–biotin technique. Biotinylated antibody and FDA-labeled avidin were applied to the assay sequentially. The performance was compared with the traditional sandwich-type assay for mouse immunoglobulin G detection. Following the immunoreaction, the nanocrystals were released by hydrolysis and dissolution instigated by adding a large volume of organic solvent/sodium hydroxide mixture. The limit of detection was lower (by a factor of 2.5–21) and the sensitivity was (3.5–30-fold) higher than immunoassays using commercial labeling systems (FITC and peroxidase). This study shows that using fluorescent nanocrystals in combination with the avidin–biotin technique can enhance assay sensitivity and provide a lower limit of detection without requiring long incubation times as in enzyme-based labels.     

Palladium complexes with Pd-->B dative bonds: analysis of the bonding in the palladaboratrane compound [kappa4-B(mimBut)3]Pd(PMe3)

The dinuclear complex {[mu-kappa(1),kappa(3)-B(mim(Bu(t)))(3)]Pd}(2), which features a Pd-->B dative bond, may be obtained by the reaction of [Tm(Bu(t))]K with Pd(OAc)(2); treatment of {[mu-kappa(1),kappa(3)-B(mim(Bu(t)))(3)]Pd}(2) with PMe(3) affords the mononuclear boratrane derivative [kappa(4)-B(mim(Bu(t)))(3)]Pd(PMe(3)), for which a molecular orbital analysis indicates that the palladium center possesses a d(8) configuration.     

Preparation and characterization of Gd2O3:Eu rods by surfactant assemblies—microwave heating

Gd₂O₃:Eu³⁺ rods were successfully obtained by microwave heating the as-prepared substance, which templated by surfactant assemblies of gadolinium hydroxide and europium hydroxide, formed in a reaction between Gd(NO₃)₃-Eu(NO₃)₃ and urea. Transmission electron microscopy (TEM) characterizations indicated that the synthesized rods with an averaging diameter of 100-150 nm and agglomerates slightly. Powder X-ray diffraction (XRD) results indicated that the resultant rods were cubic Gd₂O₃. The luminescent of Gd₂O₃:Eu³⁺ rods were investigated by photoluminescence (PL). Upon excitation with 257 and 277 nm, respectively, Gd₂O₃:Eu³⁺ rods show a strong red emission line at around 611 nm. Furthermore, this novel method required a very short heating time, thus reducing the energy consumption.     

A study on photo-generated charges property in highly ordered TiO2 nanotube arrays

In this study TiO₂ nanotube arrays were fabricated by potentiostatic anodization of titanium sheet. The X-ray diffraction (XRD) pattern and field emission scanning electron microscopy (FE-SEM) image indicated the TiO₂ nanotube arrays were of pure anatase form and highly ordered. The properties of the photo-generated charges in the nanotube arrays were investigated by transient photovoltage (TPV) technique and surface photovoltage (SPV) technique based on lock-in amplifier with dc bias, in comparison with the commercial powder derived film. The separation processes of the photo-induced charges in the system of TiO₂ nanotubes on Ti have been demonstrated to be correlated with the incident light intensity, surface trapping states, and the interfacial electric field between Ti and TiO₂. The results also show that the highly ordered nanotube film could generate much stronger SPV responses under external electric field than the commercial powder derived film.