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介绍了实验室研制的微波电子回旋共振(ECR)等离子体阴极电子束系统及初步研究结果,该系统包括微波ECR 等离子体源、电子束引出极、聚焦线圈等。通过测量水冷靶电流和靶上的束斑尺寸,实验研究了微波ECR 等离子体阴极电子束的流强、聚束性能等随电子束系统工作条件的变化。结果表明:微波输入功率越高、引出电压越高,引出电子束流强越大;工作气压对电子束流强的影响较复杂,随气压增加呈现出先降低后升高的特点;在7×10−4Pa 的极低气压下电子束流强可达75mA,引出电压9kV;能量利用率可达0.6;调整聚焦线圈的驱动电流,电子束的束斑直径从20mm 减小到13mm,电子束流强未有明显变化。 相似文献
53.
研究了积分路径差分吸收(IPDA)激光雷达中采用洛伦兹线型代替伏格特线型对机载平台探测CO2柱浓度精度的影响。建立仿真模型,讨论两种线型在数据反演中对温度和气压的敏感性,以及探测相对误差变化随飞行高度的变化。结果表明:伏格特和洛伦兹线型得到的吸收截面,温度和气压敏感性,相对随机误差分别为0.860%,-0.703%和0.224%,基本没有差别,但是洛伦兹线型可以有效地提高光谱参数计算效率。机载IPDA激光雷达采用洛伦兹线型可以快速高精度反演飞行路径上CO2柱浓度,降低了对系统计算能力的要求,有助于实现在飞期间数据实时反演和分析,以及实施针对突发事件的飞行规划,同时也有助于进一步实现机载激光雷达系统的小型化和集成化。 相似文献
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Laser-induced breakdown spectroscopy(LIBS) is used to determine the total nitrogen(TN) and total phosphorus(TP) in soil.Quantitative determinations are conducted using the line intensity of the analyte element and element concentration.Calibration models are obtained using ten samples for TN and seven samples for TP.The rest samples are used to validate the results.Strong linear correlations are obtained from the determined TN and TP concentrations.LIBS is a powerful tool for analyzing soil samples to determine nutrient elements by selecting calibration and validation samples with similar matrix composition. 相似文献
56.
Jin Sen Wang Hui Li Lei Luo Xiao Sun Xianshun Zuo Ming Tian Jie Zhang Xiaodong Xie Yi 《中国科学:化学(英文版)》2021,64(11):1964-1969
Science China Chemistry - Extracting photogenerated species from bulk to surface is an essential process for gaining efficient semiconductor-based photocatalysis. However, compared with charged... 相似文献
57.
Kexuan Zhang 《中国物理 B》2021,30(12):126802-126802
The interfacial enhanced ferromagnetism in maganite/ruthenate system is regarded as a promising path to broaden the potential of oxide-based electronic device applications. Here, we systematically studied the physical properties of LaLa1-xCaxMnO3/SrRuO3 superlattices and compared them with the LaLa1-xCaxMnO3 thin films and bulk compounds. The LaLa1-xCaxMnO3/SrRuO3 superlattices exhibit significant enhancement of Curie temperature (TC) beyond the corresponding thin films and bulks. Based on these results, we constructed an extended phase diagram of LaLa1-xCaxMnO3 under interfacial engineering. We considered the interfacial charge transfer and structural proximity effects as the origin of the interface-induced high TC. The structural characterizations revealed a pronounced increase of B-O-B bond angle, which could be the main driving force for the high TC in the superlattices. Our work inspires a deeper understanding of the collective effects of interfacial charge transfer and structural proximity on the physical properties of oxide heterostructures. 相似文献
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Environmental monitoring is getting more important nowadays due to the greater stress faced by the natural environment in the era of urbanisation and industrialisation. To accomplish the task, rapid and reliable analytical probes are essentially needed to perform the monitoring at real time basis with high sensitivity and accuracy. In view of this, analytical probes developed using carbon nanoparticles are one of the latest alternatives that are proven with capability to detect various analytes of the environment. Carbon nanoparticles portray good fluorescence property that enables the integration onto optical sensing transducers. Further engineering via surface functionalization can be performed in the interest to improve the selectivity and sensitivity of the probes. There are several advantages of using carbon nanoparticles and the most significant benefit is the sustainability prospect as compared to other groups of fluorophores. Carbon nanoparticles can be synthesised with greener approach via simple pyrolysis or hydrolysis processes that involve minimum use of toxic or harmful starting precursors, besides able to tap on using renewable resources such as carbon rich agricultural wastes. The synthesis is often performed under mild condition and produces less or no side chemical products. Carbon nanoparticles by nature show low toxicity effect to the environment. This review focuses specifically of the sustainable significances, advantages and achievements in adopting carbon nanoparticles as an alternative for environmental monitoring. 相似文献
60.
《中国化学快报》2020,31(6):1593-1597
As one of the most environmentally friendly photovoltaic(PV) conversion equipments,aqueousprocessed CdTe nanocrystal solar cells(NC SCs) have attracted great interest in recent years because of their excellent properties such as high charge-carrier mobility and broad absorption.However,two issues including interfacial recombination and leakage current seriously restrict their performance.In this paper,insulating polymer poly(vinyl pyrrolidone)(PVP) is introduced into CdTe NC SCs to solve the problems.The experimental results of transmission electron microscopy(TEM),atomic force micro scopy(AFM) and dark current measurements,etc.,demonstrate the leakage current is effectively suppressed by introducing PVP.Through further designing device structure,the reduction of interfacial recombination after introducing PVP is confirmed.By strategically taking the advantages of PVP properties(e.g.,water solubility and thermostability),the power conversion efficiency of the devices with PVP is enhanced by almost 37% compared to pure CdTe devices.This work demonstrates an effective and low-cost method to fabricate NC SCs via aqueous route.Moreover,it also proves that appropriate content of insulating polymer is of beneficial in promoting the PV performance. 相似文献