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181.
By analyzing accurate theoretical results from solving the time-dependent Schr?dinger equation of atoms in few-cycle laser pulses, we established the general conclusion that laser-generated high-energy electron momentum spectra and high-order harmonic spectra can be used to extract accurate differential elastic scattering and photo-recombination cross sections of the target ion with free electrons, respectively. Since both electron scattering and photoionization (the inverse of photo-recombination) are the conventional means for interrogating the structure of atoms and molecules, this result implies that existing few-cycle infrared lasers can be implemented for ultrafast imaging of transient molecules with temporal resolution of a few femtoseconds.  相似文献   
182.
Optical Review - This paper describes the noise analysis of an electro-optic (EO) sensor system based on experimental and simulation results. We developed a polarization simulator of the EO sensor...  相似文献   
183.
李晴棉  高淑琴 《发光学报》1995,16(4):365-367
近年来随着光纤技术的发展,各种光纤传感器日臻完善。我们先后制作出光纤微压力传感器、光纤液位传感器、光纤高温传感器以及用于化学溶液的浓度测量等系列光纤传感器。由于社会和生产的需要,在我所过去研究工作的基础上,又研制出光纤编码器的实验样机。本文阐述研制的光纤编码器的工作原理、设计制作及技术指标。并对其应用范围进行讨论。  相似文献   
184.
A dinitrile compound containing ethylene oxide moiety (4,7-dioxa-1,10-decanedinitrile, NEON) is synthesized as an electrolyte solvent for high-voltage lithium-ion batteries. The introduction of ethylene oxide moiety into the conventional aprotic aliphatic dinitrile compounds improves the solubility of lithium hexafluorophosphate (LiPF6) used commercially in the lithium-ion battery industry. The electrochemical performances of the NEON-based electrolyte (0.8 M LiPF6?+?0.2 M lithium oxalyldifluoroborate in NEON:EC:DEC, v:v:v?=?1:1:1) are evaluated in graphite/Li, LiCoO2/Li, and LiCoO2/graphite cells. Half-cell tests show that the electrolyte exhibits significantly improved compatibility with graphite by the addition of vinylene carbonate and lithium oxalyldifluoroborate and excellent cycling stability with a capacity retention of 97 % after 50 cycles at a cutoff voltage of 4.4 V in LiCoO2/Li cell. A comparative experiment in LiCoO2/graphite full cells shows that the electrolyte (NEON:EC:DEC, v:v:v?=?1:1:1) exhibits improved cycling stability at 4.4 V compared with the electrolyte without NEON (EC:DEC, v:v?=?1:1), demonstrating that NEON has a great potential as an electrolyte solvent for the high-voltage application in lithium-ion batteries.  相似文献   
185.
基于多样品多型号仪器的测试信息及其GUM和MCM方法,讨论了四步干涉法测量红外光学材料折射率均匀性的测量范围及其测量不确定度评定。红外干涉测量的绝对灵敏度和准确度虽不及可见激光干涉仪,但采用了四步干涉测量的方法,消除了干涉仪的固有系统误差,有利于实现对红外光学材料折射率均匀性的高准确度测量。实际测试表明,该测量范围覆盖110-5~510-3,测量相对标准不确定度为210-1~210-2。  相似文献   
186.
Impairments resulting from stroke lead to persistent difficulties with walking. Subsequently, an improved walking ability is one of the highest priorities for people living with stroke. The degree to which gait can be restored after a stroke is related to both the initial impairment in walking ability and the severity of paresis of the lower extremities. However, there are some patients with severe motor paralysis and a markedly disrupted corticospinal tract who regain their gait function. Recently, several case reports have described the recovery of gait function in stroke patients with severe hemiplegia by providing alternate gait training. Multiple studies have demonstrated that gait training can induce “locomotor-like” coordinated muscle activity of paralyzed lower limbs in people with spinal cord injury. In the present review, we discuss the neural mechanisms of gait, and then we review case reports on the restoration of gait function in stroke patients with severe hemiplegia.  相似文献   
187.
Nanowires are promising candidates for energy storage devices such as lithium-ion batteries, su- per(:apa.citors and lithium-air batteries. However, simple-structured nanowires have some limitations hence the strategies to make improvements need to be explored and investigated. Hierarchical nanowires with enhanced periormanee have been considered as an ideal candidate for energy storage due to the novel structures and/or synergistic properties. This review describes some of the recent progresses in the hierarchical nanowire merits, classification, synthesis and performance in energy storage applieat, ions. Herein we discuss the hierarchical nanowires based on their structural design from three major categories, including exterior design, interior design and aligned nanowire assembly. This review also briefly outlines the prospects of hierarchical nanowires in morphology control, property enhancement and application versatility.  相似文献   
188.
紫外写入光纤光栅应变传感特性研究   总被引:2,自引:1,他引:2  
采用紫外写入光纤Bragg光栅研究其应变传感特性。光纤光栅要借助外界应力引起轴向应变和折射率变化造成光栅Bragg反射波长移动。在温度20℃,利用波长在400 ̄1800nm范围色散的光谱仪并用InGaAsP/InP ELD作宽带光源,从实验上测量了光纤光栅的应变与Bragg反射波长间的关系,结果表明Bragg反波长移动与光纤光栅外界应力变化在155.4 ̄156.8nm波长范围呈线性。外界应力引起的  相似文献   
189.
Journal of Nanoparticle Research - A green bioreduction method was used to prepare highly efficient supported TiO2 photocatalysts with bimetallic (Au-Ag) nanoparticles at room temperature using...  相似文献   
190.
Water-soluble constituents of dill   总被引:1,自引:0,他引:1  
From the water-soluble portion of the methanol extract of dill (fruit of Anethum graveolens L.), which has been used as a spice and medicine, thirty-three compounds, including a new monoterpenoid, six new monoterpenoid glycosides, a new aromatic compound glucoside and a new alkyl glucoside were obtained. Their structures were clarified by spectral investigation.  相似文献   
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