Design and fabrication of GeAsSeS chalcogenide waveguides with thermal annealing

We reported a chalcogenide glass-based rib waveguide fabricated using photolithography and dry etching method. A commercial software(COMSOL Multiphysics) was used to optimize the waveguide structure and the distribution of the fundamental modes in the waveguide based on the complete vector finite component. We further employed thermal annealing to optimize the surface and sidewalls of the rib waveguides. It was found that the optimal annealing temperature for Ge As Se S films is 220℃, and the roughness of the films could be significantly reduced by annealing. The zero-dispersion wavelength(ZDW) could be shifted to a short wavelength around ~2.1 μm via waveguide structural optimization, which promotes supercontinuum generation with a short wavelength pump laser source. The insertion loss of the waveguides with cross-sectional areas of 4.0 μm×3.5 μm and 6.0 μm×3.5 μm was measured using lens fiber and the cut-back method. The propagation loss of the 220℃ annealed waveguides could be as low as 1.9 d B/cm at 1550 nm.     

钢管混凝土柱抗火性能的试验研究

对2个钢管混凝土柱进行了抗火性能的试验研究。试验采用足尺试验形式,柱长3800mm,钢管外部有20mm厚砂浆保护层。通过试验,得出钢管混凝土柱的截面温度场分布规律和耐火极限。试验结果表明,砂浆保护层的存在使得钢管表面温度比炉内温度降低大约300℃～500℃,提高了钢管混凝土柱的耐火极限。钢管混凝土柱第一次受火达到炉内最高温度810℃,没有破坏,冷却到常温,第二次受火,柱子破坏,破坏时炉内最高温度为828℃。与一次受火破坏钢管混凝土柱相比较,炉内最高温度降低了122℃,二次受火钢管混凝土柱耐火极限温度明显降低。上述结果可为今后结构抗火性能的研究提供依据。     

在载体催化体系下二乙基锌对乙烯聚合催化效率的影响及调节分子量的动力学研究

本文对比研究了用(Ⅰ):TiCl_4/MgCl_2/Al(C_2H_5)_3和(Ⅱ):TiCl_4/MgCl_2/Al(C_2H_5)_3/Zn(C_2H_5)_2两种载体催化体系在常压下进行乙烯配位聚合的动力学行为,测定了聚合速率V_p、T_i活性中心比浓度[C~*]、聚合活化能△E、聚合速率常数K_p及链增长寿期L值。并分别测定以Al(C_2H_5)_3与Zn(C_2H_5)_2为链转移剂的链转移速度常数乓K_(tr,Al)与K_(tr,Zn)以及链转移活化能△E_(tr,Al)与△E_(tr,Zn)。表明Zn(C_2H_5)_2能有效地进一步提高催化效率和降低聚乙烯的分子量并进行讨论。