Ni-Sm-MgO催化热解CO制备碳纳米管

在550～750℃，通过CO在Ni-Sm-MgO催化剂上催化歧化制备了碳纳米管．在Ni-MgO催化剂中加入Sm，提高了催化剂的活性和稳定性．对催化剂进行XRD和TPR表征结果表明M和Sm之间有强相互作用，Sm促进了Ni-MgO固溶体中Ni^2＋的还原．碳产物的TEM和TGA表征结果表明，在650℃得到的碳纳米管产率高（达到600％以上）、质量好．利用Ni-Sm-MgO催化剂上CO歧化制备碳纳米管是具有应用前景的大规模、低成本制备碳纳米管的方法．     

Observation of stable bound soliton with dual-wavelength in a passively mode-locked Er-doped fiber laser

A phase-locked bound state soliton with dual-wavelength is observed experimentally in a passively mode-locked Erdoped fiber(EDF) laser with a fiber loop mirror(FLM). The pulse duration of the soliton is 15 ps and the peak-to-peak separation is 125 ps. The repetition rate of the pulse sequence is 3.47 MHz. The output power is 11.8 mW at the pump power of 128 mW, corresponding to the pulse energy of 1.52 nJ. The FLM with a polarization controller can produce a comb spectrum, which acts as a filter. By adjusting the polarization controller or varying the pump power, the central wavelength of the comb spectrum can be tuned. When it combines with the reflective spectrum of the fiber Bragg grating, the total spectrum of the cavity can be cleaved into two parts, then the bound state soliton with dual-wavelength at 1549.7 nm and 1550.4 nm is obtained.     

Mg-Al合金熔体中固液界面结构的分子动力学研究

本文采用分子动力学研究了Mg-3%Al合金熔体中固液界面结构及界面附近原子的扩散行为.计算结果表明,该二元合金的固液界面为粗糙界面.垂直于界面方向的数密度分布,表现出复杂波动的特征,这种波动一直延伸到液体中.在界面附近的区域,扩散系数的三个不同方向的分量表现出了明显的各向异性,并且这种各向异性一直持续到液相当中.对界面二维结构的分析表明,界面附近液相原子的二维排列呈现出从长程有序逐渐过渡到短程有序的变化.     

基于FPGA的PLC数据输出控制IP核设计

提出应用FPGA设计PLC数据输出控制IP核的思路。该IP核执行输出数据相关命令时,在内部时序脉冲控制下按照Y编号地址自主完成数据在存储单元的寻址和读写操作;论述了控制器的工作原理和电路设计,应用Verilog语言实现硬件电路的构建及功能;测试表明:该IP核可以自主完成对数据处理和输出要求,使数据输出与系统其它功能模块实现并行处理,提高了PLC运行速度。