Application of a neural network model with multimodal fusion for fluorescence spectroscopy

In energy-dispersive X-ray fluorescence spectroscopy,the estimation of the pulse amplitude determines the accuracy of the spectrum measurement.The error generated by the amplitude estimation of the pulse output distorted by the measurement system leads to false peaks in the measured spectrum.To eliminate these false peaks and achieve an accurate estimation of the distorted pulse amplitude,a composite neural network model is proposed,which embeds long and short-term memory(LSTM)into the UNet structure.The UNet network realizes the fusion of pulse sequence features and the LSTM model realizes pulse amplitude estimation.The model is trained using simulated pulse datasets with different amplitudes and distortion times.For the pulse height estimation,the average relative error of the trained model on the test set was approximately 0.64%,which is 27.37% lower than that of the traditional trapezoidal shaping algorithm.Offline processing of a standard iron source further validated the pulse height estimation performance of the UNet-LSTM model.After estimating the amplitude of the distorted pulses using the model,the false peak area was reduced by approximately 91% over the full spectrum and was corrected to the characteristic peak region of interest(ROI).The corrected peak area accounted for approximately 1.32%of the characteristic peak ROI area.The results indicate that the model can accurately estimate the height of distorted pulses and has substantial corrective effects on false peaks.

Interaction between Ternary Rare Earth Complexes of Cinnamic Acid and Phenanthroline with DNA by Spectroscopy

The interaction of ternary complexes [RE(phen)(cin)_3(H_2O)](RE= Nd (III),Ce(III),Eu(III))with calf thymus DNA was investigated by electronic absorption spectroscopy, ethidium bromide(EB)-DNA quenching fluorescent spectra and resonance light scattering. All experimental results indicate that the three complexes bind to DNA by the electrostatic mode and the intercalative mode. It is predicted that these complexes show high anticancer activity or other biologic activity.

Experimental Determination of the Vibrational Constants of FeS（X5 △） by Dispersed Fluorescence Spectroscopy

Based on previous laser-induced fluorescence excitation spectroscopy work, the vibrational constants of neutral FeS in the X5 △ electronic state were obtained by directly mapping the ground-state vibrational levels up to v＂=3 using conventional laser-induced dispersed fluorescence spectroscopy. The vibrational frequency of FeS（X5 △） （518±5 cm-1） agrees well with that reported in a recent PES measurement （520±30 cm-1） [J. Phys. Chem. A 107, 2821 （2003）] which is the only one prior experimental vibrational frequency value for the 5 △ state of FeS. Careful comparisons of our experimental results and those documented in the literature （mainly from theoretical predictions） suggest that the ground state of FeS is 5 △ state.

Dissolved Organic Matter Features of Three Adjacent Eastern Mediterranean Urbanized Watersheds

Landscape urbanization broadly affects ecosystems in coastal watersheds, but, until now, the influence of nonpoint source urban inputs on dissolved organic matter (DOM) amount, composition, and source is poorly understood. To understand how DOM composition varied with urbanization, fluorescence excitation-emission matrices (EEMs) were determined for urban and non-urban waters from upstream to downstream sites along three adjacent coastal watersheds that flow into the Mediterranean Sea. Two humic DOM fluorescent components (humic-like and fulvic-like peaks) and two proteinic components (tyrosine-like and tryptophane-like peaks) were identified by EEM fluorescence. The results indicated that urbanization had an important influence on DOM concentration and composition, with urban waters having a high degree of DOM variation due to different land uses surrounding each body of water. Urban waters show a higher DOM fluorescence index (FI), the highest fluorescence intensity of protein-like manifested also by BIX values, and a lower value of the humification index (HIX) than non-urban waters which were dominated by allochthonous inputs. In addition, the EEM was compared in dry and wet season where higher DOM amounts and FI appeared in summer due to autochthonous production coming from algae growth compared to allochthonous input from rainfall dominated in wet season. The concentration of DOC increased from upstream to downstream for the three rivers, especially Beirut River. The increase in DOC values was observed in both dry and wet seasons by 39 and 19 times respectively compared to upstream (0.93 - 0.91 mgC/L).

Study to mechanism of fluorescence enhancement of Dy3＋-Gd3＋- SSA-CTMAB system by resonance scattering-light spectroscopy

The fluorescence enhancement mechanism of Dy3＋-Gd3＋- SSA-CTMAB system was studied by the resonance light scattering and fluorescence spectrum. In this paper, the influencing factors including the concentration of Gd3＋, ligands, pH value as well as surfactants were studied. As a result, the optimal experimental conditions were obtained. The existence of molecule congeries was proved by scattering-light spectrum.

Characteristics of extracellular fluorescent substances of aerobic granular sludge in pilot-scale sequencing batch reactor

The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.

Effect of Temperature, pH and Salt on Fluorescent Quality of Water Extractable Organic Matter in Black Soil

Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction temperature, pH value, and salt on the water extractable organic matter （WEOM） was determined by means of the UV absorbance, fluorescence excitation-emission matrix, and derived fluorescence indexes. In general, the carbon content and aromaticity of WEOM increased with the increasing of extraction temperature, with the exception that there was no significant difference in the amount at 0 and 20℃. More fluorophores, especially microbially-derived organic matter were extracted at high temperature. The pH values of extractant, including 5, 7, and 10, showed no effect on the carbon amount of WEOM, whereas the aromaticity and microbially-derived component gradually increased with the increasing of pH values. The fluorescence intensity of humic acid-like fluorophore was stronger in neutral and alkali condition than that in acidic condition. The addition of 10 mmol L-1 CaCl2 significantly decreased the carbon amount of recovered WEOM. Moreover, it significantly decreased the aromaticity of WEOM and the quantity of fulvic acid-like and humic acid-like fluorophores, whereas increased the percentage of tyrosine-like and tryptophan-like fluorophores in the total fluorophores and the amount of microbially-derived organic matter. Generally, 10 mmol L-1 KCl showed the same influence trend, but with low influence degree.

Investigation of ultrafast dynamics of CdTe quantum dots by femtosecond fluorescence up-conversion spectroscopy

The ultrafast carrier relaxation processes in CdTe quantum dots are investigated by femtosecond fluorescence upconversion spectroscopy.Photo-excited hole relaxing to the edge of the forbidden gap takes a maximal time of ～ 1.6 ps with exciting at 400 nm,depending on the state of the photo-excited hole.The shallow trapped states and deep trap states in the forbidden gap are confirmed for CdTe quantum dots.In addition,Auger relaxation of trapped carriers is observed to occur with a time constant of ～ 5 ps.A schematic model of photodynamics is established based on the results of the spectroscopy studies.Our work demonstrates that femtosecond fluorescence up-conversion spectroscopy is a suitable and effective tool in studying the transportation and conversion dynamics of photon energy in a nanosystem.

Fluorescence spectroscopy characteristics of humic acid by inoculating white-rot fungus during different phases of agricultural waste composting

The white-rot fungus, Phanerochaete chrysosporium (P. chrysosporium), was inoculated during different phases of agricultural waste composting, and its effect on the fluorescence spectroscopy characteristics of humic acid (HA) was studied. The results show that the emission spectra have a sharp peak at 400 nm and a broad shoulder with the maximum centered at 460 nm. The excitation spectra have two peaks and exhibit red shift (shift to longer wavelengths) at 470 nm. The synchronous scan spectra present a number of peaks and shoulders, and the peaks at shorter wavelengths disappear gradually and form a shoulder. At the final stage of composting, the fluorescence spectra have similar shapes, but the fluorescence intensities decrease. P. chrysosporium increases the degree of aromatization and polymerization of HA when it is inoculated during the second fermentation phase, while it does not produce an obvious change on the humification degree of HA when it is inoculated during the first fermentation phase. Compared with the fluorescence spectroscopy characteristics of HA from soil, the structure of HA from compost is simpler and the activity is higher.

Investigation on the Photodissociation of Oxygen from Oxymyoglobin by Fluorescence Spectroscopy

Photodissociation of oxygen from oxymyoglobin（oxyMb） was investigated by means of fluorescence spectroscopy. One of the most important findings of the photodissociation of oxyMb was the discovery of two processes which were affected by excitation intensity, temperature, solvent viscosity, and excitation wavelength. Process I（PI） corresponded to oxygen escaping from the binding site at ferrous heme iron atom within the porphyrin ring into the heme pocket, whereas process II（PII） was ascribed to oxygen escaping from the heme pocket into the solvent. To elucidate this interesting phenomenon, we proposed a model that oxygen encountered two barriers on its way from the binding site at the ferrous heme iron to the solvent. Reversibility and wavelength sensitivity of the photodissociation were also observed.

Preparation and Characterization of Ternary Europium ComplexDoped Thin SolGel Hybrid Film by Fluorescence Spectroscopy

Ternary europium complex with dibenzoylmethane(DBM)and 1,10phenanthroline(phen)was insitu synthesized in thin SiO2/polyvinyl butyral(PVB)hybrid films by a twostep solgel process and characterized by means of fluorescence spectroscopy.The luminescence spectra,fluorescence lifetimes and photostability were all investigated.The results showed that the hybrid films exhibited the characteristic emission bands of the central rare earth Eu3+.In addition,Eu3+presented longer fluorescence lifetime than in an ethanol solution and the complex had a higher photostability in the hybrid film than in the PVB film containing the corresponding pure complex.

Solvent-Induced Symmetry-Breaking Charge Transfer in an Octupolar Triphenylamine Derivative Resolved with Transient Fluorescence Spectroscopy

The excited-state symmetry-breaking charge transfer (SBCT) dynamics in quadrupolar or octupolar molecules without clear infrared markers is usually hard to be tracked directly. In this work, on the basis of the evolution of instantaneous emission dipole moment obtained by femtosecond transient fluorescence spectroscopy, we presented a real-time characterization of the solvent-induced SBCT dynamics in an octupolar triphenylamine derivative. While the emission dipole moment of the octupolar trimer in weakly polar toluene changes little during the excited-state relaxation, it exhibits a fast reduction in a few picoseconds in strongly polar tetrahydrofuran. In comparison with the uorescence dynamics of dipolar monomer, we deduced that the emitting state of the octupolar trimer in strongly polar solvent, which undergoes solvent-induced structural uctuation, changes from exciton-coupled octupolar to excitation localized dipolar symmetry. In weakly polar solvent, the octupolar symmetry of the trimer is largely preserved during the solvation stabilization.

Fast Evaluation Peanut Oil Quality by Synchronous Fluorescence Spectroscopy and Statistical Analysis

Peanut oil oxidation was to monitor and quantify combining synchronous fluorescence spectroscopy and chemometrics. Peanut oil was subjected to an accelerated oxidation testing. The spectral and related chemical indicators were caught during oxidation induce testing. Fluorescence spectra were gained for each sample with simultaneous excitation from 200 to 800 nm and the offsets (Δλ) of 10 to 180 nm during the oxidation process. The results showed the induce period (IP) of the peanut oil was 16.45 h. Parallel factor analysis (PARAFAC) was performed to select the best Δλ interval of 70 nm, which spectral data was the most suitable for interval partial least square (iPLS) and synergy interval PLS (siPLS) modeling and forecast. The study presented all interval selection methods had the better results than the global spectrum modelling. iPLS reached the best into 10 intervals with a ratio of prediction to deviation (RPD) of 2.10. siPLS that separated the whole spectrum into 15 intervals and combined the third intervals (282 to 320 nm, 362 to 400 nm, and 761 to 800 nm) had a ratio of RPD of 2.26. The results showed the optimal siPLS model performed a little better than iPLS. The established model lying on interval selection could improve the prediction accuracy. It could provide a quick, accurate method to monitor oil oxidation process.

Study of a Model Humic Acid-type Polymer by Fluorescence Spectroscopy and Atomic Force Microscopy

A model HA-type polymer of para-benzoquinone synthetic humic acid (SHA) and its complexes with copper, iron and manganese metal ions were studied using atomic force microscopy (AFM). Natural humic acids (HA) and synthetic humic acids (SHA) were examined by fluorescence spectroscopy, which indicated similarity of SHA and HA spectra. The AFM images of SHA and its complexes revealed variable morphologies, such as small spheres, aggregates and a sponge-like structure. The SHA complexes displayed morphologies similar to those of natural HA. The presence of copper, iron and manganese ions led to the formation of aggregate-type structures in an apparent arrangement of smaller SHA particles.

Characterization of Anabaena cylindrica Solution System Using Synchronous-Scan Fluorescence Spectroscopy

The characterization of the algae Anabaena cylindrical solution with Fe (III)was investigated using fluorescence emission and synchronous-scan spectroscopy. The ranges ofconcentrations of algae and Fe (III) in aqueous solutions were 5.0 X 10~7-2.5 X10^8 cell/L and 10-60mu mol/L, respectively. The effective characterization method used was synchronous-scanfluorescence spectroscopy (SFS). The wavelength difference (triangle open lambda) of 90 nm wasmaintained between excitation wavelength (lambda_(ex)) and emissionwavelength(lambda_(em)). The peakwas observed at about lambda_(ex) 236 nm / lambda_(em) 326 nm for synchronous-scan fluorescencespectroscopy. The fluorescence quenching in system of algae-Fe( III )-HA was studied usingsynchronous-scan spectroscopy forthe first time, Fe(III) was clearly the effective quencher. Therelationship between I_0/I (quenching efficiency) and c (concentration of Fe (III). added) was alinear correlation for the algae solution with Fe(III). Also, Aldrich humic acid (HA) was found tobe an effective quencher.

Structure and Orientation of 1-(Hydroxyl)-5-(dodecyloxy)-naphthalene LB Films by Polarized Fluorescence Spectroscopy

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｒｅｃｅｎｔｙｅａｒｓ，Ｌａｎｇｍｕｉｒ－Ｂｌｏｄｇｅｔ（ＬＢ）ｆｉｌｍｓｈａｖｅａｔｒａｃｔｅｄｍｕｃｈａｔｅｎｔｉｏｎｂｅｃａｕｓｅｏｆｔｈｅｉｒｐｏｓｉｂｉｌｉｔｉｅｓａｓｆｕｎｃｔｉｏｎａｌｍｏｌｅｃｕｌａｒｄｅｖ...

Laser Induced Fluorescence Spectroscopy of IrN

High resolution laser induced fluorescence, spectra of IrN in the spectral region between 394 and 520 nm were recorded using laser vaporization/reaction free jet expansion and laser induced fluorescence spectroscopy. Seven new vibronic transition bands were observed and analyzed. Two Ω=1 and five Ω=0 new states were identified. Least squares fit of rotationally resolved transition lines yielded accurate molecular constants for the upper states. Spectra of isotopic molecules were observed, which provided confirmation for the vibrational assignment. Comparison of the observed electronic states of IrB, IrC, and IrN provides a good understanding of the chemical bonding of this group of molecules.

THE RAPID DETERMINATION FOR BENZO(a)PYRENE WITH SYNCHRONOUS FLUORESCENCE SPECTROSCOPY SCANNING IN DEFINED RANGE OF DUAL—WAVELENGTHS

A rapid method of determination of BaP in various environmental samples,using synchronous fluorescence spectroscopy scanning in defined range of dual-wavelengths(SFDW)is described in this paper.

Sorption Characteristics of Rare Earth Element Eu ^(3+) onto Silica-Water Interfaces Studied by Fluorescence Spectroscopy

The sorption of Eu species onto nano-size silica-water interfaces was investigated using fluorescence spectroscopy for pH ranges of 1-8.5 and an initial Eu concentration (C Eu) of 2×10 -4 M. The sorption rate of Eu was initially low, but significantly increased at pH>4. The sorption density of Eu species on a silica surface was ～1.58×10 -7 mol/m2 when the dissolved Eu species were completely sorbed onto silica-water interfaces at pH=～5.8. The sorbed Eu species at pH<6 is aquo Eu 3+, which is sorbed onto silica-water interfaces as an outer-sphere complex at pH<5, but may be sorbed as an inner-sphere bidentate complex at 5<pH<6, due to the decrease of N H 2O to ～6 at pH=6. At pH=6-8.5, Eu(OH)+ 2, Eu(CO 3)+ and Eu(CO 3)- 2 formed in the solutions, and Eu(CO 3)+ is dominant at pH=～7.5. These ions may be sorbed onto silica-water interfaces as inner-sphere bidentate complexes.

Combination of Micro-fluidic Chip with Fluorescence Correlation Spectroscopy for Single Molecule Detection

A single molecule detection technique was developed by the combination of a single channel poly （dimethylsiloxane）/glass micro-fluidic chip and fluorescence correlation spectroscopy （FCS）. This method was successfully used to determine the proportion of two model components in the mixture containing fluorescein and the rhodamine-green succinimidyl ester.