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1.
Fluorescence emission spectra of yeast cell suspensions stained with calcofluor have recently been identified as promising markers of variations in the quality of yeast cell wall. It is shown in this paper how the raw fluorescence spectra of calcofluor can be transformed to reliable spectral signatures of cell wall quality, which are independent of actual dye-to-cell concentrations of examined cell suspensions. Moreover, the presented approach makes it possible to assess basis fluorescence spectra that allows for the spectral unmixing of raw fluorescence spectra in terms of respective fluorescence contributions of calcofluor solvated in the suspension medium and bound to yeast cell walls. 相似文献
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We previously applied the electrochromic modulation of excited-state intramolecular proton-transfer (ESIPT) reaction for the
design of novel 3-hydroxyflavone (3-HF) derivatives as fluorescent probes for measuring the dipole potential, ΨD, in lipid bilayers (Klymchenko et al., Proc. Natl. Acad. Sci. USA, 2003, 100, 11219). In the present work, this method was revisited to take into account the influence of the bilayer hydration on the
emission ratiometric response of 3-HF probes. For this reason, it was necessary to deconvolute the whole fluorescence spectra
into three bands corresponding to the non H-bonded forms, normal N* and tautomer T* forms, both participating to the ESIPT reaction, and to the H-bonded H–N* form, excluded from this reaction. This allowed us to determine the pure N*/T* intensity ratio, without any contribution from the H–N* form emission depending essentially on the bilayer hydration. This new approach allowed us to confirm the correlation we
obtained between the response of 3-HF probes on dipole potential modifications and the corresponding response of the reference
fluorescent probe di-8-ANEPPS, thus further confirming the potency of 3-HF probes as excellent emission ratiometric probes
to measure dipole potential in lipid membranes. 相似文献
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U. Rambabu K. Annapurna T. Balaji J. V. Satyanarayana K. Rajamohan Reddy S. Buddhudu 《光谱学快报》2013,46(5):833-839
The fluorescence properties of Eu3 + and Tb3+ doped Na6La(BO3)3, Na6Gd(BO3)3, Na6Y(BO3)3, Na6(Gd, Y) (BO3)3 powder phosphors are reported. These phosphors display fluorescent RED and GREEN colours when droped with Eu3+ and Tb3+ ions, respectively. The best fluorescence performance was consistantly observed from the Na-Gd based hosts. The photoluminescence spectra were analysed by evaluating colour coordinates, relative intensity ratios, and stimulated emission cross-sections. 相似文献
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In a previous paper the results of the Langmuir probe experiment carried out on board of two INTERKOSMOS satellites have been described. The experiences have shown that the usage of high quality algorithms for analyzing the current-voltage-characteristics is necessary to yield real physical parameters. The key problem is the determination of the plasma potential. This paper reviews the different methods to determine the plasma potential especially under the circumstances of computer application. The test of the well developed methods shows, that for the evaluation of the applied methods a number of different factors, discussed in the following sections of this paper, has to be taken into account. The used test data are model values or real measurements obtained by the satellite missions IK-10, IK-18 and BULGARIA-1300. The computer procedures have been realized as FORTRAN-subroutines for the BESM 6 and ES 1040. 相似文献
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晶体Zn(antipyrine)2(NO3)2:VO2+的EPR谱及光吸收谱的理论研究 总被引:1,自引:1,他引:0
由于硝酸钒锌二安替比林晶体[Zn(antipyrine)2(NO3)2:VO2 ]中配体O2-的自旋-轨道耦合参量ζ0p≈150 cm-1与中心过渡族3d1离子V4 的ζ0d≈248 cm-1相差不太大,故配体的自旋-轨道耦合参量ζ0p对电子顺磁共振(EPR)谱和光吸收谱的贡献必须考虑.采用双自旋-轨道耦合参量模型和相关的晶体场能级公式,计算了Zn(antipyrine)2(NO3)2:VO2 晶体的EPR谱和光吸收谱,所得理论结果与实验发现很好符合;确定了该晶体的局域对称结构沿C4轴的四角畸变约为0.45 nm;计算发现,较大的κ值说明VO2 中未配对的s电子对超精细结构常数有较大的贡献.并对上述这些结果的合理性进行了讨论. 相似文献
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城市空气质量监测系统(DOAS)谱线漂移问题及解决方法 总被引:2,自引:0,他引:2
城市空气质量监测系统中差分光学吸收光谱法的光学部分受到外界影响(温度、光纤位置等),或是氙灯自身的变化,都会引起测量谱线的漂移。如果灯信号谱与大气测量信号谱谱线漂移不一致而产生谱线相对偏移,将直接影响测量结果的准确性。因此,在运用DOAS方法进行大气痕量气体污染物浓度反演时,必须对大气测量信号谱和灯信号谱进行波长匹配。文章通过对氙灯自身发射光谱特殊结构的研究,提出了利用氙灯特征发射峰,通过对两个信号光谱进行最小二乘拟合,达到谱线校正的方法。实验结果证明,这种方法可以有效地减小谱线相对偏移对大气痕量气体污染物浓度反演结果的影响。 相似文献
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以NH4Cl-NH3·H2O为缓冲液,十六烷基三甲基溴化铵(CTAB)为荧光增强剂,用荧光分光光度计分别采集槲皮素、槲皮素-Sn(Ⅱ)配合物溶液、槲皮素-Sn(Ⅱ)-NH4Cl-NH3·H2O、槲皮素-Sn(Ⅱ)-NH4Cl-NH3·H2O-CTAB溶液以及将其溶液分别静置7h和21h后的荧光光谱,并对光谱进行分析.在不加CTAB的条件下,用紫外分光光度计分别测量加入缓冲液前后的紫外光谱.用漫反射方法测定配合物的红外光谱,并对其结构进行初步分析.在缓冲液的作用下,槲皮素-Sn(Ⅱ)配合物的结构发生了变化;通过分析,发现与缓冲液发生反应的主要基团为酚羟基,红外光谱中酚羟基的消失和NH 4基团的出现,说明了配合物中的酚羟基与NH 4发生了取代反应. 相似文献
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以NH4Cl-NH3.H2O为缓冲液,十六烷基三甲基溴化铵(CTAB)为荧光增强剂,用荧光分光光度计分别采集槲皮素、槲皮素-Sn(II)配合物溶液、槲皮素-Sn(II)-NH4Cl-NH3.H2O、槲皮素-Sn(II)-NH4Cl-NH3.H2O-CTAB溶液以及将其溶液分别静置7h和21h后的荧光光谱,并对光谱进行分析。在不加CTAB的条件下,用紫外分光光度计分别测量加入缓冲液前后的紫外光谱。用漫反射方法测定配合物的红外光谱,并对其结构进行初步分析。在缓冲液的作用下,槲皮素-Sn(II)配合物的结构发生了变化;通过分析,发现与缓冲液发生反应的主要基团为酚羟基,红外光谱中酚羟基的消失和NH4+基团的出现,说明了配合物中的酚羟基与NH4+发生了取代反应。 相似文献
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Investigation of the Emission Cross-sections and the Spectra of (Cr~(4 ), Yb~(3 ) ): YAG Crystal 总被引:2,自引:0,他引:2
l introductionIn recent years, Cr4 --doped crystals have attracted a great deal of attention aspassive Q--,wit,h.,[l~4]. These Cr4 --dOPed crystals include Cr4 : YAG[l'21 ) Cr4 :GSGG[s], Cr4 : YSO['] etc. They have a large absorption cross section and lOwsaturable intensity at the laser wavelength. In comparison with previously usedsaturable absorbers such as dyes['] and LiF: FZ-- [6] cOlor center crystals, Cr4 -dopedcrystals are more photO--chemically and thermally stable and h… 相似文献
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This research note reports the fluorescence properties of Eu3+-doped in three sets of (Y-Zn, La-Zn and Gd-Zn) oxy fluoride powder phosphors. on excitation with a UV-source, these phosphors have displayed orangish-red color and for which the chromaticity coordinates ([Xbar], [Ybar] have been computed. the relative fluorescence intensity ratios (R) for the different measured emission transitions have been evaluated in order to examine the effect of substitution of zinc ions in the host matrix on the fluorescence behavior. Scanning electron microscopy studies have also been performed to investigate the average grain size of the synthesized phosphor material. 相似文献
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Walsh MS Xu LH Lees RM Mukhopadhyay I Moruzzi G Winnewisser BP Albert S Butler RA DeLucia FC 《Journal of Molecular Spectroscopy》2000,204(1):60-71
New millimeter-wave and microwave measurements for CH(3)OD have been combined with previous literature data and with an extended body of Fourier transform far-infrared observations in a full global analysis of the first two torsional states (v(t) = 0 and 1) of the ground vibrational state. The fitted CH(3)OD data set contained 564 microwave and millimeter-wave lines and 4664 far-infrared lines, representing the most recent available information in the quantum number ranges J = 20 and K = 15. A 53-parameter converged global fit was achieved with an overall weighted standard deviation of 1.060, essentially to within the assigned measurement uncertainties of +/-100 kHz for almost all of the microwave and millimeter-wave lines and +/-6 MHz for the far-infrared lines. The new parameters for CH(3)OD are compared to previous results obtained for the (12)CH(3)OH, (13)CH(3)OH, and CD(3)OH isotopomers over the same quantum number ranges using the identical fitting program. Strong asymmetry-induced coupling between the accidentally near-degenerate 0E and -1E v(t) = 0 substates is successfully modeled by the fit. Copyright 2000 Academic Press. 相似文献
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B. Serrano J. C. Cabanelas J. González-Benito J. Baselga J. Bravo 《Journal of fluorescence》1997,7(4):341-345
The polymerization of cyclohexylmethacrylate was monitored, over a wide temperature range, by simultaneous differential scanning calorimetry (DSC) and fluorimetry (FL); the equipment for both being optically coupled. Pyrene was used as a fluorescent probe. There was excellent agreement between the exothermic peak time obtained by DSC and the time at which the maximum gradient was obtained in the fluorescence intensity–time curves, but only for temperatures above 60°C, Activation energies for the gel effect onset were obtained for both, the conversion–time and intensity–time curves being concordant except for data at low temperatures, below 60°C. It was concluded that vitrification occurs at temperatures below 60°C and its presence was demonstrated by fluorimetry, by means of the conversion change associated with the fluorescence intensity jump(off-on). 相似文献
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FCVAD合成Ta-C(N)薄膜及其Raman和XPS分析 总被引:1,自引:0,他引:1
掺N非晶金刚石Ta—C(N)薄膜是合成β—C3N4研究中出现的一种新型固体薄膜材料,近年来由于其优异的电化学性能受到越来越多的关注。我们用磁过滤阴极真空弧等离子体沉积(FCVAD)方法在不同N2分压下,在Si衬底上合成了Ta—C(N)薄膜。Raman和XPS分析表明Ta—C:N薄膜中的N主要以C—N的方式与C结合。N2分压越大,N/C原子比越高,最高可达31.1%。但同时sp^3键含量越低,并且合成Ta-C:N薄膜的速度越慢。 相似文献
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J. KoperskiM. Czajkowski 《Journal of Molecular Spectroscopy》2002,212(2):162-170
First-time observed D1(1Π)v′=10→X0+(1Σ) fluorescence in ZnAr, and A0+(3Π)v′=4→X0+ and D1(1Π)v′=7,8→X0+ fluorescence in CdAr van der Waals (vdW) molecules were produced in a continuous supersonic molecular beam crossed with a pulsed dye-laser beam, following excitation of single vibronic levels. The dispersed fluorescence spectra displayed characteristic Condon internal diffraction (CID) patterns consisting of bound-free, reflection type, continuous spectra, and, in certain cases, bound-bound discrete features. An analysis of the A0+→X0+ and D1→X0+ bound-bound spectra indicates that Morse functions are adequate representations of the X0+ potential energy (PE) curves below their dissociation limits. In simulation of the A0+→X0+ and D1→X0+ bound-free spectra, the Morse, Lennard-Jones L-J(n−6), and Maitland-Smith M-S(n0,n1) functions were tested, and the respective M-S(11.3, 9.0) and M-S(10.6, 7.0) potentials were found to be good representations for the repulsive walls of the X0+ PE curves of ZnAr and CdAr, respectively, over the short range, R=2.45-4.38 Å (ZnAr) and R=2.85-4.31 Å (CdAr), of internuclear separations. 相似文献
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Claudio A. Téllez S. Sergio G. de la Riva Eduardo Hollauer Ionel Haiduc Cristian S. Silvestru 《光谱学快报》2013,46(7):1469-1483
Abstract The infrared and Raman spectra of dimethyldithiophosphinate anion (CH3)2PS2 were measured and the vibrational modes for the anion complex were assigned. A Normal Coordinate Analysis in the Modified General Valence Force Field (MGVFF) approximation was carried out assuming C2v symmetry. Ab Initio Calculations at RHF and MP2 level were also carried out for the anion geometry as well as for its frequencies, intensities and force constants. 相似文献