建筑设计中新与旧的关系探讨

本文通过具体的实例,探讨了处理建筑设计中新和旧关系的三种思路。建筑师只有把握好新与旧矛盾的主次关系,才能为设计的展开打下坚实的基础。     

Effects of the processing steps on parathion levels during honey production and parathion removal by macroporous adsorption resins

The effects of different steps in honey production on parathion levels and parathion removal from honey using macroporous adsorption resins (MARs) were investigated in this study. Parathion residues were quantified by gas chromatography with flame photometric detection (GC-FPD) after each processing step including preheating, filtration, vacuum concentration and pasteurization. The four processing steps could reduce the initial parathion level of 2.77 to 2.73, 2.53, 2.30 and 2.23 mg/kg, respectively, and the total loss of parathion was only 19%. Meanwhile, different types of MARs were used in parathion adsorption, and the results from removal experiments showed that LS-803 resin was more efficient in removing parathion from honey than other resins LS-903, LSA-21 and LSA-900B, with the adsorption rate of above 90%.     

Synthesis, optical properties and ultrafast dynamics of a 2,1,3-benzothiadiazole-based red emitter with intense fluorescence and large two-photon absorption cross-section

A new 2,1,3-benzothiadiazole-based red fluorescent compound with a D-A-D type structure was synthesized and characterized. The central 2,1,3-benzothiadiazole core was symmetrically connected via the 4,7-positions with two donor groups in which the 7-position of a fluorenyl ring was substituted with a carbazol-9-yl moiety and the 2-position was substituted by a 5-thienyl moiety. The carbazol moieties were further derivatized by two 2-naphthyl moieties at the 3,6-positions. Femtosecond laser spectroscopic techniques including excited state fluorescence and pump-probe technique investigations, together with steady state absorption and one-photon fluorescence spectra, were employed to systematically investigate the optical properties and ultrafast dynamics of the new compound in tetrahydrofuran solution. It shows a large two-photon absorption cross-section and high fluorescence quantum yield, indicating potential application in two-photon fluorescence imaging field. The ultrafast dynamics results reveal competition between a pure excited state relaxation process and stimulated radiation in the red wavelength region.