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91.
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93.
Controlling the gain shape of Er^3+—doped fluorozirconate fibre amplifier by a coherent field
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We proposed a four-level system to explore the quantum interference effects on optical amplification.We found that the gain of the probe.including positions and values of gain peaks,can be adjusted by changing the coherent field and the incoherent pumping.At the same time,we can also modify the absorption profile of electromagnetically induced transparency by the incoherent pump.The results provide a method to flatten the gain of Erbium-doped fibre amplifiers. 相似文献
94.
曲轴激光喷丸强化试验研究 总被引:2,自引:2,他引:0
采用实验的方法,研究了激光冲击强化对175A型柴油机曲轴疲劳寿命的影响,取得了激光冲击强化试验条件下曲轴过渡圆角处残余应力场的数据。并将激光冲击强化工艺效果和曲轴滚压强化效果做了对比性分析,结果表明:虽然激光冲击强化效果不如曲轴滚压强化,但考虑到激光工艺参数精确可控、加工质量好、成本低以及可避免滚压强化所造成的表面疲劳、撕痕等,激光冲击强化工艺可望代替滚压强化成为新型的曲轴强化手段。通过此类激光冲击强化强化实验可优化激光冲击的相关参数,使曲轴过渡圆角产生有利的残余应力场。 相似文献
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96.
New polyaniline (PANI) asymmetric membranes were fabricated using a phase‐inversion technique with hexane as the coagulation bath. These membranes exhibit a dense structure with macrovoids distributed asymmetrically throughout the cross‐section. A stress–strain study demonstrated that the Young's modulus (1.421 GPa) and strain at break (7.6 %) of the new PANI asymmetric membranes prepared from hexane are approximately 12 and 4 times higher, respectively, than the values reported previously for the PANI integrally skinned asymmetric membranes (ISAMs) (123 MPa Young's modulus and 1.8 % strain at break). Furthermore, monolithic electrochemical actuators based on a single PANI asymmetric membrane were constructed, and a bending movement of up to 20 Hz was experimentally recorded in a hydrochloric acid aqueous solution. A lifetime of over 329 500 cycles was determined for these actuators at a ± 2° angular displacement (5 Hz). The lifetime is limited by a bending fatigue that creates a transversal crack on the PANI membrane at the air–water interface. Control over the actuator movement is also manifested by the linear dependences of the bending angle on the charge and of the angular velocity on the current. These relationships are independent of both the kind of applied electric signal and the frequency used. 相似文献
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98.
在氨性溶液中,光照射对ZnTPPS的形成影响很大。光-极谱试验表明:光电流(i_p)与浓度(c)间有以下的关系:对Zn(NH_3)_4~(2+),i_p∝C_((Zn)(NH_3)_4)~(2+)_~(1/2),对H_2TPPS,i_p∝C_(H_2TPPS),ZnTPPS络合物还原波的i_p不明显。本文对其差异性和光电流产生的原因做了初步探讨。 相似文献
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100.
Reactions of the hydrated electron, H atoms, 2-propanol, and methanol radicals with the TiO2 nano-particles have been studied either directly or by competition kinetics. The radicals were produced by radiolysis of 2-propanol, t-butanol, or methanol aqueous solutions in acid pH's. The reactions involve electron injection to the conduction band. As expected, the t-butanol radical is inert towards TiO2 under our conditions, while the other reducing radicals react with TiO2. The reactivity decreases in the order: eaq−>H>CH3COHCH3>CH2OH. Two TiO2 nanocrystallite sizes, with average diameters of 1.0 and 4.7 nm were compared. For equal concentrations (in terms of TiO2 molecules), the rate of electron injection shows relatively little dependency on particle size. The rates of interfacial electron transfer and transfer coefficient are also reported. 相似文献