共查询到19条相似文献,搜索用时 46 毫秒
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试提出一种高荧光及强背景噪声情况下表面增强拉曼散射光谱的提取方法。该方法从分析荧光谱及背景噪声信号的组成入手,构建相应模型对荧光谱及噪声信号进行估计,通过比较估计结果与实际数据的差别识别谱峰信号,并定位谱峰的基底位置。通过在若丹明6G、前列腺特异抗原测量及pH值传感实验中的实际应用检验可知,该方法可提高表面增强拉曼散射光谱信号的分辩率和测量准确度,在微量物质鉴别及物质含量定量测量方面有较好的应用前景。 相似文献
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余多慰 《光谱学与光谱分析》1998,18(3):303-306
利用拉曼散射光谱测试技术,对不同温度处理后获得的各种相对湿度下的鲱精DNA纤维进行脱氧核苷C—H振动与结合水O—H振动行为分析,以揭示其中结合水的数量特征。结果表明,运用25926×I2964/I3024新指标所获数据与文献报道的小牛胸腺DNA水合状态拉曼数据不同,但与小牛胸腺DNA、鲑精DNA的红外、X射线衍射、重量分析及差示扫描量热分析所得数据相吻合,证明拉曼分析公式的修订是成功的。鲱精DNA纤维应与上述二种DNA纤维具有同样的水合状态,每核苷酸对含有9~14个结合水分子。 相似文献
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用高荧光效率的有机染料芘(perylene)掺杂聚乙烯咔唑(PVK),其荧光光谱与芘的发射光谱基本一致,而且亮度比纯芘发光提高十多倍,说明发光主要来自芘分子,并在PVK和perylene之间存在十分有效的能量传递或电荷转移过程,荧光谱强度随掺杂浓度的变化关系说明存在一个最佳的掺杂浓度比.分析PVK和perylene之间可能发生的能量转移过程,认为从PVK到perylene这种能量转移与实验不符;分析PVK和perylene薄膜的光致发光过程,认为从(PVK+)→(perylene+)和从(PVK-)→(p 相似文献
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通过拉曼光谱及荧光光谱测量研究了采用低压金属有机化学沉积(MOCVD)方法生长的InGaN/GaN多量子阱高温快速热退火处理对量子阱光学性质的影响。观测到退火后InGaN/GaN量子阱的拉曼光谱E2,A1(LO)模式的峰位置出现了红移,而且该振动峰的半高宽也有微小变化。温度升高退火效果更明显。退火使量子阱内应力部分消除,同时In,Ga原子扩散出现相分离使拉曼谱表现出变化。在常温和低温下的光荧光谱表明,退火处理的量子阱发光主峰都出现了红移;而且低温退火出现红移,退火温度升高相对低温退火出现蓝移;同时在低温荧光光谱里看到经过退火处理后原发光峰中主峰旁边弱的峰消失了。讨论了退火对多量子阱光学性质的影响。 相似文献
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本文在室温下测量了GdOBr:Eu的常压和高压荧光谱,光谱范围在13000~21500cm-1之间,压力至12GPa.常压下,清晰可辨的荧光谱线共有43条,这些谱线由Eu3+4f6组态内5D0-2至7F0-5的跃迁产生。由荧光谱线得到26个晶场能级(Stark能级).谱线绝大部分随压力红移,少数几条谱线随压力先蓝移后红移。所有谱线的强度随压力升高而减弱。7F0-5的能级随压力的变化规律比较复杂,而5D0-5各能级均随压力的升高几乎线性地降低。 相似文献
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为了拓展染料掺杂聚合物光纤的应用范围,利用甲基丙烯酸甲酯(MMA)单体合成了掺有Coumarin540和Rhodamine 6G两种激光染料的聚甲基丙烯酸甲酯(PMMA)聚合物玻璃棒,并将其拉制成直径约1 000μm的聚合物光纤。以市售LED灯为光源,在侧向照明和前端照明两种条件下分别研究了染料掺杂的聚合物光纤中染料的荧光、荧光传输损耗以及光纤的光谱下转换等性质。两种染料的Stokes波长红移幅度分别达到70 nm和50 nm。在掺杂浓度分别为0.01 mg/g和0.04 mg/g时,侧向照明条件下测得两种光纤分别对520nm和577 nm的荧光的传输损耗为0.336 cm-1和0.343 cm-1。在前端照明条件下,在光纤输出端获得了较高下转换效率的光谱输出,其转换效率与染料掺杂浓度和光纤长度有关。这种染料掺杂的聚合物光纤有可能与石英玻璃光纤耦合,对其所传输的光进行光谱下转换的光频调控以更好地满足不同的应用需求。 相似文献
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W. G. J. H. M. van Sark P. L. T. M. Frederix D. J. van den Heuvel A. A. Bol J. N. J. van Lingen C. de Mello Donegá H. C. Gerritsen A. Meijerink 《Journal of fluorescence》2002,12(1):69-76
Room-temperature time-resolved luminescence measurements on single CdSe/ZnS quantum dots (QDs) are presented. Fluorescence emission spectra were recorded over periods of up to 30 minutes with a time resolution as small as 6 ms. For QDs in ambient air, a clear 30–40 nm blue shift in the emission wavelength is observed, before the luminescence stops after about 2–3 minutes because of photobleaching. In a nitrogen atmosphere, the blue shift is absent while photobleaching occurs after much longer times (i.e., 10–15 minutes). These observations are explained by photoinduced oxidation. The CdSe surface is oxidized during illumination in the presence of oxygen. This effectively results in shrinkage of the CdSe core diameter by almost 1 nm and consequently in a blue shift. The faster fading of the luminescence in air suggests that photoinduced oxidation results in the formation of non-radiative recombination centers at the CdSe/CdSeOx interface. In a nitrogen atmosphere, photoinduced oxidation is prevented by the absence of oxygen. Additionally, a higher initial light output for CdSe/ZnS QDs in air is observed. This can be explained by a fast reduction of the lifetime of the long-lived defect states of CdSe QDs by oxygen. 相似文献
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WANG Yan YIN Shaotang YU Xiling Zhang Qingli Wang Aihua CAO Yuhui CHANG Yong WANG Xiaoguang 《中国光学快报(英文版)》2002,11(3)
The fluorescence spectra of Cr,Tm,Ho∶YAG crystal have been detected at the temperature from 65 to 295 K with interval of 10 K.The width and the shift of Ho3+ lines at 4959.6 cm-1 (at 65 K) have been investigated and interpreted in terms of the interactions between lattice vibration (phonons) and ions.The results showed that the line broadening with the temperature was mainly due to the Raman scattering of phonons,and the line shift with temperature was mainly due to the emission and absorption of virtual phonons. 相似文献
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基于胶原基表面活性剂(collagen-based surfactant,CBS)中酪氨酸(Tyr)和苯丙氨酸(Phe)的荧光特性,应用恒波长差(Δλ)为15 nm的同步荧光光谱技术研究CBS浓度、溶液pH值、NaCl浓度和温度对其在水溶液中分子的聚集行为的影响,并以温度为外扰,利用二维同步荧光相关分析研究CBS分子中Tyr残基和Phe残基随温度变化的响应顺序。结果表明,CBS分子在261和282 nm处出现了分别归属于Phe和Tyr的特征吸收峰。随着CBS浓度的升高,CBS分子中Phe残基和Tyr残基数量逐渐增多使CBS分子聚集程度增加,并导致荧光强度增强;CBS溶液pH值(pH 5.0)在等电点附近时,由于CBS分子的疏水作用和氢键形成能力加强,导致CBS分子聚集程度增强;CBS溶液中NaCl浓度的升高,则使CBS分子间排斥力减弱,从而导致CBS分子的聚集;然而温度升高,CBS由聚集状态逐渐变为单分子状态,因猝灭、变性以及氢键形成能力降低,荧光强度逐渐降低。以温度为外扰的二维同步荧光相关光谱分析可知:低温下(10~40 ℃ ),CBS聚集体随温度升高逐渐松散,位于聚集体内部的Phe残基比Tyr残基优先响应;而在45~70 ℃时,CBS由单分子状态逐步水解为无规卷曲构造,Tyr残基的间距变大,氢键形成能力大大降低,Tyr残基比Phe残基优先响应。 相似文献
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分别在298,310,318 K温度下,利用荧光光谱法研究了pH=7.40生理条件下硝基羟乙唑(TRI)与溶菌酶(LYSO)的相互作用机理。结果表明,TRI与LYSO间通过静态猝灭方式相互作用。测定了LYSO与TRI反应的结合常数、结合位点数。利用反应过程的热力学参数,确定了LYSO-TRI体系的作用力类型;由Hill系数得出了LYSO或TRI的协同性;根据非辐射能量转移理论,确定了TRI到LYSO的结合距离,同时采用同步光谱法考察了TRI对LYSO构象的影响。 相似文献
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The successful combination of Raman spectroscopy and fluorescence labelling of single bacterial cells is presented. The results show that the selected dyes (DAPI, SYTO 9, CFDA, SYTOX blue and PI) in most cases do not influence the Raman spectrum of a labelled bacterium significantly compared to an unstained bacterium spectrum. The labelling of bacteria offers the possibility of live/dead or biotic/abiotic differentiation prior to a Raman identification step. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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WANG Yan YIN Shaotang YU Xiling ZHANG Qingli WANG Aihua CAO Yuhui CHANG Yong WANG Xiaoguang 《Chinese Journal of Lasers》2002,11(3):228-232
The fluorescence spectra of Cr,Tm,Ho:YAG crystal have been detected at the temperature from 65 to 295 K with interval of 10 K. The width and the shift of Ho3+ lines at 4959.6 cm-1 (at 65 K) have been investigated and interpreted in terms of the interactions between lattice vibration (phonons) and ions. The results showed that the line broadening with the temperature was mainly due to the Raman scattering of phonons,and the line shift with temperature was mainly due to the emission and absorption of virtual phonons. 相似文献
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Steady-state and time-resolved fluorescence polarization studies have been carried out on acenaphthene (ACE) in low-temperature glass solutions and at room temperature. In the low-temperature glass the fluorescence polarization values vary considerably with both emission and excitation wavelength. There is a time dependence (on the nanosecond time scale) of the fluorescence anisotropy, r(t), at 77 K, which has a strong dependence upon the excitation and emission wavelengths. Under these conditions, the time-dependent decay of the anisotropy is not attributable to chromophoric motion. The observations are consistent with emission from two closely lying and interconverting excited states. Rate constants for the photophysical processes involved have been determined by fitting the data using a model proposed by Fleming et. al. The results are discussed with particular reference to the care required in using dynamic fluorescence polarization measurements to determine energy transfer rates in systems containing this chromophore. 相似文献