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We demonstrated a femtosecond mode-locked Er:Zr F4-Ba F2-La F3-Al F3-Na F(Er:ZBLAN)fiber laser at 2.8μm based on the nonlinear polarization rotation technique.The laser generated an average output power of 317 m W with a repetition rate of 107 MHz and pulse duration as short as 131 fs.To the best of our knowledge,this is the shortest pulse generated directly from a mid-infrared mode-locked Er:ZBLAN fiber laser to date.Numerical simulation and experimental results confirm that reducing the gain fiber length is an effective way to shorten the mode-locked pulse duration in the Er:ZBLAN fiber laser.The work takes an important step towards sub-100-fs mid-infrared pulse generation from mode-locked Er:ZBLAN fiber lasers. 相似文献
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新型苯选择加氢制环己烯非晶态催化剂Ru-Fe-B/ZrO2的制备及其可调变性 总被引:1,自引:0,他引:1
采用化学还原法制备了一种新型高活性和高选择性苯选择加氢制环己烯的Ru-Fe-B/ZrO2纳米非晶态合金催化剂,并利用透射电镜、选区电子衍射、X射线衍射和N2物理吸附仪等手段对催化剂进行了表征.重点研究了Ru-Fe-B/ZrO2催化剂活性和选择性的可调变性,及还原剂NaBH4浓度和洗涤后滤液的pH值对其催化性能的影响.结果表明,在新型Ru-Fe-B/ZrO2催化剂上,当苯转化54%时,环己烯选择性高达80%,同时环己烯选择性随苯转化率升高而缓慢下降.向反应浆液中添加酸性或碱性物质可以调变催化剂的活性和选择性,同时催化剂制备工艺和性能具有很好的可重复性.Ru-Fe-B/ZrO2催化剂融合了纳米和非晶材料的特性,这是其对苯选择加氢制环己烯表现出高活性和高选择性的主要原因. 相似文献
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We theoretically study the phase characteristic of optical parametric amplification (OPA) or chirped pulse OPA (OPCPA) pumped by two phase-distorted laser beams. In the two-beam-pumped optical parametric amplification (TBOPA), due to spatial walk-off, both of the pump phase distortions will be partly transferred to signal in a single crystal so as to degrade the signal beam-quality, which will be more serious in high-energy OPCPA. An OPA configuration with a walkoff-compensated crystal pair is demonstrated for reducing the signal phase distortion experienced in the first stage and ensuring the signal phase independent of two pump phase distortions through the second crystal, hence maintaining the signal beam-quality. Such a TBOPA is similar to the conventional quantum laser amplifier by means of eliminating its sensitivity to the phase and number of the pump beams. 相似文献
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论述了Socket(套接字)机制的工作原理,介绍了Delphi中Socket通信机制的编程技术。在此基础上,运用多线程技术实现多层分布式应用系统的数据分发。 相似文献
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随着B2I用户规模的增长,其数据流量快速增加,给现有网络资源带来较大冲击,用户感知保障压力较大.采用多视角研究B2I流量分布特性及其增长趋势,对于聚焦热点高负荷区域扩容投资具有较大的实际意义. 相似文献
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从大客量数字微波通信系统传输过程中发生的多径衰落入手,介绍了数字微波通信系统中空间分集接收机的加权评估合成技术。 相似文献
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应用红外光谱技术分别获取了苹果表皮黄色、红色和褐色损坏部位的红外光谱图,进行了苹果表面色泽变化的光谱特性研究.通过对红外光谱图的分析及研究发现:在855nm和910nm两波长处,黄色部位、红色部位和褐色损坏部位的吸收峰出现了明显的差异,因此可通过研究表面色泽变化的红外光谱特性来判别苹果好坏. 相似文献
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从介绍第三代移动通信主要特点和关键技术入手,简要分析cdma2000、MWCDMA、TD-SCDMA几种技术的异同点和第三代移动通信市场的发展趋势。 相似文献