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考察了Pd(acac)_2/Ph_3P均相体系催化丁二烯和醇类调聚反应,比较了Pd(acac)_2/Ph_3P催化不同醇类与丁二烯调聚反应的结果。研究了Pd(acac)_2催化剂的重复利用。探索了其它过渡金属络合物如镍和铑络合物催化丁二烯与甲醇调聚反应。 相似文献
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We demonstrate a carrier-envelope phase-stabilized octave-spanning oscillator based on the monolithic scheme. A wide output spectrum extending from 480 nm to 1050 nm was generated directly from an all-chirped mirror Ti:sapphire laser. After several improvements, the carrier-envelope offset(CEO) beat frequency accessed nearly 60 d B under a resolution of 100 k Hz. Using a feedback system with 50-k Hz bandwidth, we compressed the residual phase noise to 55 mrad(integrated from 1 Hz to 1 MHz) for the stabilized CEO, corresponding to 23-as timing jitter at the central wavelength of790 nm. This is, to the best of our knowledge, the smallest timing jitter achieved among the existing octave-spanning laser based frequency combs. 相似文献
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One-dimensional method of investigating the localized states in armchair graphene-like nanoribbons with defects 下载免费PDF全文
In this paper we propose a type of new analytical method to investigate the localized states in the armchair graphenelike nanoribbons. The method is based on the tight-binding model and with a standing wave assumption. The system of armchair graphene-like nanoribbons includes the armchair supercells with arbitrary elongation-type line defects and the semi-infinite nanoribbons. With this method, we analyze many interesting localized states near the line defects in the graphene and boron-nitride nanoribbons. We also derive the analytical expressions and the criteria for the localized states in the semi-infinite nanoribbons. 相似文献
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光学频率梳是一种重复频率与偏置频率锁定的新型光源,在频域上为频率间隔稳定的频率梳齿,在时域上为相对距离稳定的飞秒脉冲激光.光学频率梳在测距中的应用广泛,能够实现远距离高精度的测量.本实验使用飞秒激光脉冲作为光源,基于谐振腔扫描光学采样测距原理得到非对称的互相关干涉条纹,实现了远距离高精度的绝对测距.非对称互相关条纹可通过色散补偿与调节光学频率梳的重复频率得到,并通过得到的非对称的互相关干涉条纹对测距结果进行补偿.实验结果表明测距系统能够实现在50 m范围内误差为2 μm的绝对测距,测量相对误差为1.9×10-7. 相似文献
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跨倍频程超连续光谱的产生是光学频率梳系统中测量载波包络相移频率的关键.本文采用拉锥单模光纤作为非线性光谱展宽介质, 将半导体激光(LD)抽运的掺镱硼酸钙氧钇(Yb:YCOB)振荡器输出的飞秒激光耦合到该拉锥光纤中, 通过飞秒激光在光纤中发生的相位调制、四波混频等非线性效应将光谱展宽至超过倍频程的范围.振荡器输出的飞秒激光脉冲宽度为130 fs, 中心波长为1052 nm, 重复频率为76.8 MHz, 平均功率为620 mW, 耦合进单模拉锥光纤后获得了光谱覆盖范围从550 nm至1350 nm的跨倍频程超连续光谱, 最大输出平均功率为323 mW, 耦合效率达到52%.为进一步实现全固态飞秒激光光学频率梳提供了重要基础. 相似文献