共查询到19条相似文献,搜索用时 531 毫秒
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7-羟基喹啉(7-HQ)是一种具有激发态质子转移(ESPT)效应的有机分子。它溶于乙醇溶剂中,在紫外光的激励下,将发生ESPT反应,荧光光谱出现2个荧光带。7-HQ溶于二甲基亚砜(DMS)溶剂中,则不能发生ESPT反应,其荧光光谱只出现单一荧光带。但样品被强紫外光照射后,其荧光光谱也出现2个荧光带。文章首次报道了这一现象,并通过对7-HQ的乙醇、二甲基亚砜和二甲基甲酰胺溶液的吸收光谱和荧光光谱的研究,探讨产生这一现象的机理。认为7-HQ溶于DMS中被强紫外光照射后荧光光谱的变化是由于DMS被光解并生成水而使7-HQ发生ESPT反应的结果。 相似文献
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讨论了紫外光照射乙醇和水混合溶液的荧光光谱及其对应的激发光谱,认为乙醇和水分子混 合时会发生团簇形成新的分子从而成为能辐射荧光的物质.采用不同波长的紫外光照射乙醇 水溶液,计算了不同入射光的荧光量子产率,进而选取具有最高荧光效率的激励光照射不同 混合比率溶液,通过探测混合物所发射的荧光光子数目随乙醇和水混合比率的变化规律,研 究了团簇分子的可能类型,并利用荧光强度和吸收率的加和性计算了混合物的总吸收率和总 荧光光子数目,从而解释了乙醇水溶液的荧光光谱特征峰.结果可为乙醇和水分子形成的新 团簇分子研究提供实验和理论依据.
关键词:
乙醇-水配合物
荧光光谱
分子团簇
激发光谱 相似文献
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8—羟基喹啉铝的荧光老化机制 总被引:1,自引:0,他引:1
报导了8-羟基喹啉铝(Alq3)在紫外光照射下发生荧光猝灭的机制,测量了Alq3在光照射前后的紫外-可见吸收光谱、荧光光谱、红外吸收光电子能谱(XPS),分析了紫外光照射后Alq3分子结构变化,证明了产生结构变化的根源是中水与Alq3发生了化学反应,对Alq3的我老化机制提出了可能的解释。 相似文献
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本文报道了Tb-吡哌酸生成络合物,在紫外光照射下发生分子内能量传递使Tb产生特征荧光,其荧光强度与吡哌酸的浓度成线性关系,由此建立了一种灵敏,快速的分析嘴哌酸的方法。 相似文献
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用光学线性和非线性方法研究了Y型半花菁/花生酸交替LB多层膜的光致光学各向异性。在纳秒紫外偏振脉冲激光照射下,LB多层膜中半花菁分子发色团长轴向紫外光偏振方向重新取向。加热可以使LB多层膜平面内各向异性消失及H-聚集体分解。 相似文献
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The fluorescence emitted from the gamma-ray-irradiated polyallyl diglycol carbonate upon illumination by the 346 nm UV radiation is studied. The fluorescence spectra show two distinct phenomena, the variation of fluorescence wavelength and intensity with received irradiation dose. These variations are found to be correlated to the change in the dielectric constant and the change in absorption. The dielectric constant is measured at three guiding frequencies, while the absorption is predicted with the reflected first and second diffractions of the excitation monochromator. The results support the donor-bridge-acceptor molecular origin of the fluorescence. 相似文献
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研究了300 kV脉冲电压作用下自耦式紫外预电离开关的工作原理。为了在脉冲电压下实现开关的自耦合预电离,设计了适当的分压电路及预电离结构。模拟计算表明,分压电路参数合适时,可以实现预电离间隙与开关主间隙的击穿配合。实验结果表明:在脉冲电压作用下,调节电路参数可以有效调节紫外预电离产生时刻;在适当的时刻产生紫外预电离可以有效减小开关击穿抖动;该开关在240 ns上升时间脉冲电压作用下击穿抖动可小于3 ns,在36 ns上升时间脉冲电压作用下击穿抖动可小于2 ns。 相似文献
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基于紫外预电离技术和阻容耦合电路研制了应用于高功率装置的三串联3 MV自耦式紫外预电离开关。该开关由紫外预电离间隙和开关主间隙组成。根据同类开关在脉冲电压下的击穿数据推算出3 MV开关的间隙距离,开关主间隙的电场不均匀系数为1.58。采用台阶屏蔽技术使开关有机玻璃筒外沿面最大电场小于50 kV/cm,满足设计要求。设计紫外预电离间隙击穿电压为主脉冲电压的1%,理论模拟计算表明,在0.1~0.7 MPa范围内,预电离间隙电压大于在此范围内间隙击穿电压,保证可靠预电离。 相似文献
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为构造指纹荧光检测中所需的均匀照明紫外光源,选择紫外LED阵列照明。采用光电探测器检测单颗LED的辐射角分布,拟合单个LED角分布函数;用8颗LED均匀置于半径为10 mm的圆环上,在圆环上方5 mm处的中心轴上放置一个LED;在给定的观察屏上照度不均匀误差下,根据斯派罗法则,确定观测屏与圆环阵列之间的距离,从而实现LED圆环阵列的照度分布均匀化。也可以给定观测屏到圆环的距离,确定轴上LED放置点到圆环的距离。实验结果表明,观测屏到圆环距离为11.0 cm时,在半径为10.0 mm的圆域内,照度不均匀相对误差小于1.27%。 相似文献
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对紫外预电离技术在气体开关方面的影响进行原理研究,分析并实验验证电容并联的横向辅助电极对主开关进行紫外预电离的可行性。辅助电极击穿释放紫外光,通过光电效应在主开关表面产生初始电子,以减小主开关的击穿电压离散度。预电离效果与辅助电极击穿导通电流的峰值强度、辅助电极两端的电压以及预电离储能电容有关,优化这些参数可以提高光照强度来增强预电离效果。实验结果表明:当主开关内部充满氮气、分压电容为pF量级时,距离主电极15 cm远的横向辅助电极可以产生预电离效应。在此基础上,提出一种新型的横向型电容自耦式紫外预电离开关的设计。 相似文献
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Spatially and spectrally resolved in-cylinder absorption measurements were performed in spark-ignited internal combustion
engines and in Diesel engines. With UV-broadband illumination it was shown that the UV attenuation occurs throughout the burned
gas area with roughly homogeneous absorption cross-sections. Model calculations based on the absorption properties of CO2 at elevated temperatures show that this species gives the main contribution to in-cylinder UV absorption.
A previously suggested technique of assessing UV absorption using O2 laser-induced fluorescence (LIF) as probe light is successfully applied to in-cylinder measurements of the light absorption
inside a fired heavy-duty Diesel engine. Even in this environment, the comparison with model calculations shows that CO2 is the main contributor to UV light absorption. Since the O2-LIF absorption technique is based on the identical geometry used for LIF concentration measurements, the results can directly
be used for correcting LIF signal data such as that obtained from NO imaging.
Received: 20 April 2001 / Published online: 18 July 2001 相似文献
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H. Steigerwald F. von Cube F. Luedtke V. Dierolf K. Buse 《Applied physics. B, Lasers and optics》2010,101(3):535-539
Heating and UV illumination reduce the coercive field of lithium niobate crystals. It is found that both effects add up, leading
to the conclusion that the underlying mechanisms are different. We present arguments that heating leads to an increased ionic
conductivity that changes defect structures which pin domain walls, while UV illumination enables electrical screening of
the pinning defects by photo-excited electrons. 相似文献
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Electrical Instability of Amorphous-Indium-Gallium-Zinc-Oxide Thin-Film Transistors under Ultraviolet Illumination 下载免费PDF全文
《中国物理快报》2016,(3)
The electrical instability behaviors of amorphous-indium-gallium-zinc-oxide(a-IGZO) thin-film transistors(TFTs)under ultraviolet(UV) illumination are studied.As UV radiation dosage increases,the turn-on voltage of the TFT shows continuous negative shift,which is accompanied by enhanced degradation of sub-threshold swing and field-effect mobility.The electrical instability is caused by the increased carrier concentration and defect states within the device channel,which can be further attributed to additional oxygen vacancy generation and ionization of oxygen vacancy related defects upon UV illumination,respectively.Furthermore,the performance of the a-IGZO TFT treated with UV radiation can gradually recover to its initial state after long-time storage. 相似文献