Infrared Spectra of La_(0.65)Ba_xMnO_(3-δ) Oxides

The infrared spectra of La_(0.65)Ba_xMnO_(3-|?￡(c) (x = 0.35, 0.33 and 0.30) were investigated experimentally. The result shows that the sample La_(0.65)Ba_xMnO_(3-|?￡(c) has the largest Curie temperature and the smallest resistivity and wave number of the stretching vibration mode of MnO_6 octaheUron at 300 K among the investigated samples. However, the absorption strength for the stretching vibration mode of Mn0_6 octahedron in La_(0.65)Ba_xMnO_(3-|?￡(c) is stronger for parainagnetic phase than that for ferromagnelic phase, which may be connected with the reducing of the dynamic in- coherent Jahn-Teller distortion below Curie temperature. In addition, the large shift of wave number for the stretching mode at the temperatures from 293 to 423 K has been observed in La_(0.65)Ba_xMnO_(3-|?￡(c), which may be due to the in- crease of the Mn-O bond length with temperature increasing.

Syntheses and Infrared Spectra of Rare Earth Complexes with Diethyl Phosphate

The title complexes Ln(DEP),(Ln=La,Sm,Eu,Ho and Yb)were synthesized by reaction of triethyl phosphate with trivalent rare earth chlorides.The mechanism of thermo-decomposition of the complexes has been studied.According to their IR spectra,the residues of the thermo-decomposition of the complexes were identified as Ln(PO_3)_3.Their IR spectra were measured and principal IR bands were assigned.The experimental results of the IR spectra of the complexes show that the title complexes have the same coordination form and mo- lecular configuration as rare earth,e.g.Sm,complex with dimethyl phosphate(Sm(DMP)_3).Each of the rare earth ion links three rare earth ions nearby through double“O-P-O”bridges to form a special network of rings-linking-rings,each of which consists of twenty-four atoms.The Ln-O bond is principally ionic.

Spectra selection methods:A novel optimization way for treating dynamic spectra and in-line near infrared modeling

Near infrared(NIR)spectroscopy is now widely used influidized bed granulation.However,there are still some demerits that should be overcome in practice.Valid spectra selection during modeling process is now a hard nut to crack.In this study,a novel NIR sensor and a cosine distance method were introduced to solve this problem in order to make thefluidized process into"visualization".A NIR sensor wasfixed on the side of the expansion chamber to acquire the NIR spectra.Then valid spectra were selected based on a cosine distance method to reduce the influence of dynamic disturbances.Finally,spectral pretreatment and wavelength selection methods were investigated to establish partial least squares(PLS)models to monitor the mois-ture content.The results showed that the root mean square error of prediction(RMSEP)was 0.124%for moisture content model,which was much lower than that without valid spectra selection treatment.All results demonstrated that with the help of valid spectra selection treatment,NIR sensor could be used for real-time determination of critical quality attributes(CQAs)more accurately.It makes the manufacturing easier to understand than the process parameter control.

Infrared Low-Resolution Spectra of HAEBE Stars

IRAS low-resolution spectra are presented for 36 HAEBE stars. It is found that silicate dust in amorphous or glassy form is common material in the circumstellar disks or/and shells of HAEBE stars. It is also found that the PAH feature is often appeared as well.

Characteristic wavelength selection of volatile organic compounds infrared spectra based on improved interval partial least squares

As important components of air pollutant,volatile organic compounds(VOCs)can cause great harm to environment and human body.The concentration change of VOCs should be focused on in real-time environment monitoring system.In order to solve the problem of wavelength redundancy in full spectrum partial least squares(PLS)modeling for VOCs concentration analysis,a new method based on improved interval PLS(iPLS)integrated with Monte-Carlo sampling,called iPLS-MC method,was proposed to select optimal characteristic wavelengths of VOCs spectra.This method uses iPLS modeling to preselect the characteristic wavebands of the spectra and generates random wavelength combinations from the selected wavebands by Monte-Carlo sampling.The wavelength combination with the best prediction result in regression model is selected as the characteristic wavelengths of the spectrum.Different wavelength selection methods were built,respectively,on Fourier transform infrared(FTIR)spectra of ethylene and ethanol gas at different concentrations obtained in the laboratory.When the interval number of iPLS model is set to 30 and the Monte-Carlo sampling runs 1000 times,the characteristic wavelengths selected by iPLS-MC method can reduce from 8916 to 10,which occupies only 0.22%of the full spectrum wavelengths.While the RMSECV and correlation coefficient(Rc)for ethylene are 0.2977 and 0.9999 ppm,and those for ethanol gas are 0.2977 ppm and 0.9999.The experimental results show that the iPLS-MC method can select the optimal characteristic wavelengths of VOCs FTIR spectra stably and effectively,and the prediction performance of the regression model can be significantly improved and simplified by using characteristic wavelengths.

The near-infrared spectra and distribution of excited states of electrodeless discharge rubidium vapour lamps

The population ratio between the excited states of rubidium in the electrodeless discharge rubidium vapour lamp is calculated according to the near-infrared spectra in the region of 780-1550 nm. By using a 1529 nm laser, we measure the density of natural rubidium atoms at the 5P3/2 level. The populations of different excited states are then clarified.

Identification of Complex Ions of Nb(V)in FLINAK-O^(2-)System by Infrared Spectra

The FT-IR spectra for K_2NbF_7-FLINAK-O^(2-) solution were measured and compared with the spectra of crystalline K_2NbF_7 and K_2NbOF_6.The results show that the niobium fluoro-complex and/or oxyfluoro-complex ions are presented in these solutions.NbF_7^(2-) complex ion is the predominant species in Nb(V)-FLINAK solution(not considering oxide impurity).The influence of O^(2-) on the oxyfluoro-complex ions shows that NbOF_6^(3-) as a stable monooxyfluoro-complex anion presented in FLINAK-O^(2-) systems and the number of NbOF_6^(3-) species are increased with increasing of O^(2-) when molar ratio of O^(2-)/Nb(V) is less than 1.

Alcohols＇ Classification by Infrared Spectra Segment Based on Support Vector Machines

This paper studies various classifiers to identify primary, secondary or tertiary alcohols by using segmental spectra and their combinations to support vector machines （SVMs）. The results showed that the O-H in-plane bending absorption contributed most to identification their substitute. This conclusion disagrees with related known research results.

Application of Embedded Zerotree Wavelet to the Compression of Infrared Spectra

In this paper the embedded zerotree wavelet (EZW) method and Huffman coding are proposed to compress infrared (IR) spectra. We found that this technique is much better than others in terms of efficiently coding wavelet coefficients because the zerotree quantization is an effective way of exploiting the self-similarities of wavelet coefficients at various resolutions.

Isotopic Shifts of the infrared Spectra of Cholic Acid and Sodium Cholate

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Substructure Prediction from Infrared Spectra by Using Support Vector Machines

The potential of support vector machines （SVMs） for the substructure elucidation of infrared spectra have been investigated. The trained SVMs can identify the 16 substructures with high accuracy.

The Splittings of p_± States in Infrared Spectra of Thermal Donors in Silicon

p -type CZ silicon crystals annealed at 450℃ have been investigated by low temperature infrared spectroscopy with high resolusion. It has been shown that the 2p± and 3p± bands of neutral thermal donors TD~° are all split into two bands, which have not been reported before. In addition, the concentrations ofindi- vidual TD_i and total TD have been derived from the heights of 2po bands, and the boron concentrations de- rived from that of 320 cm^(-1) band. The room temperature resistivities of samples have been evaluated and the comparison with practically measured resistivities have been made.

Study on Membrane Microstructures and Characteristics of Infrared Spectra and Nitrogen Release of Solid-Liquid Reaction Coated Urea

The membrane microstructures and the mechanism of two coated ureas formed through solid- liquid reaction were observed by scanning electron microscope and infrared spectra, the relation of the structural characteristics with the nitrogen release feature was also discussed by combining with nitrogen dissolution in water. The results showed that the membranes were made of solid particles tightly connected to each other and were piled up layer by layer through liquid glue. Porosity and aperture of membrane were determined by compactness of piled layers and the particles in a single layer and also related to the characteristics of coating materials. Research of the infrared spectra of membrane, made of a solid powder and a liquid glue, proved that O-H on the solid surface was bonded with the double bond of the liquid glue, thus forming membrane and keeping it stable. It was found that the two coated ureas showed obvious differences in nitrogen releasing due to their membrane structures, the porosity and aperture of membrane were the critical factors for nitrogen releasing.

Ab Initio Calculation of Structure and Raman and Infrared Spectra of Trifluoromethylthiosulphenyl Chloride

The molecular model of Trifluoromethylthiosulphenyl Chloride,CF_(3)SSCl,was presented.Ab initio method was used to calculate the structure and Raman and Infrared spectra.The results show that CF_(3)SSCl possess stereoscopic structure of C_(1)symmetry with a torsional angle of 94.2°.The potential energy distribution and isotope replacement methods were applied to determine the vibrational assignment.The vibrational frequencies and corresponding modes of the molecule were obtained.The calculated vibrational frequencies are in good agreement with experiments.

Raman and infrared spectra of complex low energy tetrahedral carbon allotropes from first-principles calculations

Up to now,at least 806 carbon allotropes have been proposed theoretically.Three interesting carbon allotropes(named Pbam-32,P6/mmm,and I43d)were recently uncovered based on a random sampling strategy combined with space group and graph theory.The calculation results show that they are superhard and remarkably stable compared with previously proposed metastable phases.This indicates that they are likely to be synthesized in experiment.We use the factor group analysis method to analyze theirΓ-point vibrational modes.Owing to their large number of atoms in primitive unit cells(32 atoms in Pbam-32,36 atoms in P6/mmm,and 94 atoms in I43d),they have many Raman-and infrared-active modes.There are 48 Raman-active modes and 37 infrared-active modes in Pbam-32,24 Raman-active modes and 14 infrared-active modes in P6/mmm,and 34 Raman-active modes and 35 Raman-and infrared-active modes in I43d.Their calculated Raman spectra can be divided into middle frequency range from 600 cm-1 to 1150 cm-1 and high frequency range above 1150 cm-1.Their largest infrared intensities are 0.82,0.77,and 0.70(D/Å)2/amu for Pbam,P6/mmm,and I43d,respectively.Our calculated results provide an insight into the lattice vibrational spectra of these sp3 carbon allotropes and suggest that the middle frequency Raman shift and infrared spectrum may play a key role in identifying newly proposed carbon allotropes.

Solvent effects on infrared spectra of 2—Methyl—4,5—dimethoxy—3—oxo—2H—Pyridizine：Part 2.Binary Solvent SYstems

This research on the solvent effects of 2 methyl 4,5 dimethoxy 3 oxo 2H pyridizine (MDOP) in binary solvent systems on the infrared spectra for MDOP in n hexane/CHCl 3 mixture solvents showed that there were three forms of carbonyl stretching vibration band [ υ (C=O)] of MPOP as the mole fraction of CHCl 3 in the binary solvents changes. In pure n hexane solvent, the υ (C=O) of MDOP appeared at a relatively high wavenumber. With CHCl 3 added, the υ (C=O) shifted to lower wavenumbers. Two new bands were observed over a certain range of mixture solvent compositions. The origin of the bands was discussed in the terms of two kinds of hydrogen bond together with their individual dependence on mixture composition. Comparisons were drawn for the solvent sensitivities of υ (C=O) for propanone.

Evaluation of electron-electron interactions in coupled quantum dots by using far-infrared spectra

We have studied the far-infrared spectra of two-electron vertically coupled quantum dots in an axial magnetic field by exact diagonalization. The calculated results show an obvious difference in role between the interactions for spin S = 1 and for spin S = O. The results support the possibility to evaluate the interactions by far-infrared spectroscopy in vertically coupled quantum dots.

Airborne Shortwave Infrared Spectral Remote Sensing as a Direct Prospecting Method for Oil and Gas Resources

The spectral characters of hydrocarbons in some oil-bearing strata and soil layers over oil and gas reservoirs in the Junggar Basin and northern Tarim Basin in Xinjiang are compared with those of chemically pure hydrocarbons. The hydrocarbons are characterized by the bi-absorption at 2310nm and 2350nm. Hydrocarbon and radioactive anomalies in oil and gas terrains are found much more widespread than carbonate altcrations. Based on the spectra of heavy hydrocarbons related to oil between 2270nm and 2460nm and refined data treatme nt, remote sensing may hold encouraging promise as a directly prospecting technique for oil and gas resources.

Detection of Broad Bean Diseases by Fourier Transform Infrared Spectroscopy Combined with Curve Fitting

Fourier transform infrared （FTIR） spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made up of the vibrational absorption bands of protein,lipid and polysaccharide.There were minor differences in-cluding the spectral peak position, peak shape and the absorption intensity in the range of 1 800-1 300 cm-1. There were obvious differences among their second derivative spectra in the range of 1 800-1 300 cm-1. After the procedure of the Fourier self-deconvolution and curve fitting of health bean leaves and broad bean diseased leaves in the range of 1 700-1 500 cm-1, three sub-peaks were obtained at 1 550 cm-1 （protein amide Ⅱ band）, 1 605 cm-1 （lignin） and 1 650 cm-1 （protein amide I band）.The ratios of relative areas of the bands of amide Ⅱ, lignin, and amide I were 38.86%, 28.68% and 32.47% in the spectra of healthy leaves, respec-tively. It was distinguished from the diseased leaves （chocolate spot leaf： 15.42%, 42.98% and 41.61%, ring spot leaf：32.39%, 35.63% and 31.98%, rust leaf： 13.97%, 46.40% and 39.65%, yel owing leaf curl disease leaf： 24.01%,36.55% and 39.44%）. For sub-peak area ratios （A1 563/A1 605, A1 650/A1 605 and A1 563/A1 654）, those of four kinds of diseased leaves were smal er than that of healthy leaves, and there were also differences among four kinds of diseased leaves. The results proved that FTIR combining with curve fitting might be a potential y useful tool for detecting different kinds of broad bean diseases.