大功率激光制备a-C和a-C∶H类金刚石膜的光学性能研究

采用大功率高重复频率准分子激光溅射热解石墨靶制备了类金刚石碳膜, 研究了实验条件对类金刚石膜光学性能的影响, 发现氢可以提高膜中sp3键的含量和膜的光学透过率. 在实验参数范围内, 膜的光学性能随着氢压的增加而提高. 根据类金刚石膜的反应沉积机理对上述结果进行了分析、解释.     

Enantiomerentrennung und chiroptische Eigenschaften eines 2,3-Dihydrobilatriens-abc

The enantiomers of the 2,3-dihydrobilatriene-abc1 have been separated by recycling chromatography on triacetylcellulose. Comparison of their chiroptical properties with those of amino acid substituted analogues, like3, reveals the chirality of center 3 to be of minor influence on the values. Stabilization of a definite helical conformation of these pigments seems to depend on this influence together with an appropriate dipole-dipole interaction.

     

Crystal Structure,Electrochemical Properties and Third-order Nonlinear Optical Response of 4-Methyloxy benzaldehyde Thiosemicarbazone and Its Copper(Ⅱ)Complex

Thecurrentsurgeofinterestinthefield0fnon-linearoptics(NL0)isderivedbothfromaquestforafundamentalunderstanding0fthenon-linearprocess,anditSimPortanceinthetechn0logyofphotonics.Amongnon-linearphen0mena,thethird-ordernon-linearophcsoccuPyanimPortantp0sihonbecauseitprovidesthemechanicsforophcalswitching,ophcallogic,andreal-hmeholograPhy"'.0rganicmaterialwithextendednconjugahonsandlargeRdelocalizahonsarewellknownastheimPortantmaterialsofachievinglargethird-ordernonlinearihes3.ForexamPle,thiosen…     

Non-covalent assemblies of negatively charged boronated porphyrins with different cationic moieties

A unique approach to non-covalent electron and energy transfer is described that is based on the formation of salt bridges between oppositely charged porphyrin units. A new class of electrostatically linked dimeric and pentameric porphyrins was synthesized by interaction of novel anionic boron containing porphyrins such as 5-(benzamidodecahydro-closo-dodecaborate)-10,15,20-triphenylporphyrin (N1) and meso-tetrakis-benzamidodecahydro-closo-dodecaborate)porphyrin (N2) and a variety of cationic meso-tetraarylporphyrin units. A bipyridine linked dimer (N1 · bpy · N1) was also prepared by employing N,N′-dimethyl-4,4′-bipyridinium (bpy) as a spacer between two mono-anionic species. A quinone-porphyrin dyad was also prepared for electron or energy transfer demonstration. All the synthesized assemblies were characterized by NMR, IR, UV-Vis, and mass spectroscopy. Significant spectral changes occurred in the absorption spectra of these non-covalent porphyrin assemblies compared to those of the reference monomers, indicating the presence of electronic interaction between the adjacent porphyrin units. Resonance light scattering was also used to study the formation of these assemblies in solution.     

锗的市场结构变化与光纤通信

介绍了锗在光纤通信中的作用，分析了世界光纤市场的变化及其对锗的市场结构的影响，预测近期国内锗的市场结构不会有大的变化。     

Detection of banned meat and bone meal in feedstuffs by near-infrared microscopic analysis of the dense sediment fraction

In this paper we present an alternative method for detection of meat and bone meal (MBM) in feedstuffs by near-infrared microscopic (NIRM) analysis of the particles in the sediment fraction (dense fraction (d >1.62) from dichloroethylene) of compound feeds. To apply this method the particles of the sediment fraction are spread on a sample holder and presented to the NIR microscope. By using the pointer of the microscope the infrared beam is focussed on each particle and the NIR spectrum (1112–2500 nm) is collected. This method can be used to detect the presence of MBM at concentrations as low as 0.05% mass fraction. When results from the NIRM method were compared with the classical microscopic method, a coefficient of determination (R²) of 0.87 was obtained. The results of this study demonstrated that this method could be proposed as a complementary tool for the detection of banned MBM in feedstuffs by reinforcement of the monitoring of feeds.     

Protease sensors for bioimaging

Optical imaging of specific molecular targets and pathways in vivo has recently become possible through continued developments in imaging equipment, reconstruction algorithms, and more importantly the availability of imaging reporter molecules. These reporter molecules encompass photoproteins expressed in vivo and exogenously administered probes detectable by fluorescence and/or bioluminescence imaging. One particularly enticing aspect of optical imaging is the ability to design activatible probes with inherent amplification. This review summarizes our experience in developing novel near-infrared fluorescent (NIRF) imaging agents that report on protease activities. These agents are designed to be biocompatible, highly activatible, and able to produce bright NIRF following protease cleavage.     

Optical Spectroscopy Properties of KMgF3 ：Eu^2＋ Nanocrystals and Powder Synthesized by Microemulsion and Solvothermal Process

IntroductionPerovskite complex fluorides have attracted great ainterest due to their particular physical properties, suchas piezoelectric characteristics[1], ferromagnetic prop-erty[2], nonmagnetic insulator behavior[3], and photo-luminescence host functi…     

The photoluminescence of Co-Al-layered double hydroxide

We report a new optical behaviour of pure Co-Al-layered double hydroxide (LDH).It was found that the Co-Al-LDH sample could emit fluorescence without any fluorescent substances intercalated.Its excitation spectrum shows a maximum peak near the wavelength 370nm,the maximum emission peak appears at 430 nm and the photoluminescence colour of the Co-Al-LDH sample is blue.This new optical property will be expected to extend the potential applications of LDHs in optical materials field.     

Poly(butylene terephthalate)/poly(ε-caprolactone) blends: Influence of PCL molecular mass on PBT melting and crystallization behavior

The isothermal crystallization kinetics and melting behavior of poly(butylene terephthalate) (PBT) in binary blends with poly(ε-caprolactone) (PCL) was investigated as a function of PCL molecular mass by differential scanning calorimetry and optical microscopy. The components are miscible in the melt when oligomeric PCL (M_w = 1250) is blended with PBT, whereas only partial miscibility was found in mixtures with higher molecular mass (M_w = 10,000 and 50,000). The equilibrium melting point of PBT in the homopolymer and in blends with PCL was determined through a non-linear extrapolation of the T_m = f(T_c) curve. The PBT spherulitic growth rate and bulk crystallization rate were found to increase with respect to plain PBT in blends with PCL1250 and PCL10000, whereas addition of PCL50000 causes a reduction of PBT solidification rate. The crystallization induction times were determined by differential scanning calorimetry for all the mixtures through a blank subtraction procedure that allows precise estimation of the crystallization kinetics of fast crystallizing polymers. The results have been discussed on the basis of the Hoffman-Lauritzen crystallization theory and considerations on both the transport of chains towards the crystalline growth front and the energy barrier for the formation of critical nuclei in miscible and partially miscible PBT/PCL mixtures are widely debated.