Homomorphism between cloudy and clear spectral radiance in the 800-900-cm(-1) atmospheric window region

The sensitivity of a new algorithm for cloud detection over a sea surface has been assessed on the basis of extensive simulations of clear and cloudy radiance spectra, including water and ice and low- and high-altitude clouds. The new algorithm makes use of autocorrelation and cross correlation between an observed spectrum and either a synthetic or a laboratory spectrum and can be used to determine quantitatively the degree of homogeneity of two spectra in the 800-900-cm(-1) region (11.11-12.5 microm). The scheme is intended for high-spectral-resolution observations and could form the basis for an operational stand-alone cloud-detection algorithm for next-generation sounding spectrometers. Application of the scheme to real observations is presented and discussed.     

Oscillatory Spectra of Surface Atoms in Layered Crystal (Quasi-1D Behavior)

Vibrations localized near the surface have been analyzed by the Jacobian matrix method taking into account discreteness of the lattice. It has been shown that localized surface vibrations in layered crystals with the complex lattice have quasi-one-dimensional character and their properties are described by exact solutions obtained in the framework of the one-dimensional model.     

Accurate frequency measurements for H(2)O and (16)O(3) in the 119-cm(-1)OH atmospheric window

We report frequency measurements for relatively weak H(2)O and (16)O(3) rotational transitions in the ground state and in the nu(2) = 1 vibrationally excited state. We obtained the frequency measurements by using the laboratory technique of tunable far-infrared spectroscopy with the objective of improving H(2)O and O(3) line parameters required for modeling the important atmospheric spectral window near 119 cm(-1). New sets of molecular constants are calculated from the (16)O(3) data, and improved values are reported for the frequencies of the H(2)O lines. The improvement in atmospheric simulations obtained with the new results is illustrated by comparison with recent high-resolution balloon-based atmospheric measurements. These new data significantly improve simulations of high-resolution atmospheric emission spectra.     

Complexation between Copper(II) and Glycine in Aqueous Acid Solutions by Window Factor Analysis of Visible Spectra

Window factor analysis (WFA), a self-modeling chemometric technique, is used to extract the concentration profiles of the complexes formed between Cu(II) and glycine (GlyH) during pH titration in the acid region. The visible absorption spectra of aqueous acid solutions, each containing 0.0020 M Cu(II) and 0.500 M glycine, are recorded at various pHs, ranging from 1 to 7. The concentration profiles and the spectral absorptivities of four copper species, Cu(2+), CuGlyH(2+), CuGly(+), and CuGly(2), are obtained. The spectral absorptivities of the complexes are in good agreement with those reported in the literature. The concentration profiles are used to determine the stepwise equilibrium constants of the three complexes. The reason why rank annihilation evolving factor analysis (RAEFA), a precursor technique, was not successful in resolving the spectral data is explained.     

AR(1)型自相关过程的过程能力分析方法研究

传统上进行过程能力分析是基于过程观测数据统计独立这一基本假设,而实际工作中,过程数据并不是总能满足彼此统计独立的假设前提.介绍了过程观测值符合AR(1)型自相关模型时,计算过程能力指数的方法.用一个具体案例进行分析,结果表明:数据间存在正相关时,传统方法高估了过程能力指数,而利用笔者介绍的方法可以得到正确的结论.     

Infrared absorption by methane isotopes near 2999 cm(-1): an analytical method using the Zeeman split He-Ne laser line at 2999.24 cm(-1)

We report the strengths and locations of the absorption lines of CH(3)D, (13)CH(4), and (12)CH(4) in the vicinity of the helium-neon laser line at 2999.24 cm(-1). In this region we find intrinsically strong lines of the rare species overlapping, but not precisely coincident with, intrinsically weak lines of the major species. In methane of normal isotopic composition, the lines of all three species have comparable strengths. We show how absorption measurements of the He-Ne laser, with Zeeman splitting, can be used to determine variations of the concentrations of the rare species from standard concentrations at a calculated precision of 0.5%0.     

A Study on Nanoscale Infrared Absorbent Working in Waveband Range of 1300-400 cm~(-1)

Nanoscale powder of SiO_2/Al_2O_3/TiO_2 composite was prepared by sol-gel method.Microstructure and mor- phology of the obtained samples were characterized by infrared(IR),X-ray diffraction(XRD)analysis and transmission electron microscopy(TEM).It is proved that infrared absorbing peaks of the samples are in waveband range of 1300-400 cm~(-1),and the peak shape changes with their component.Mechanism of the in- frared peak's positions and shapes which changes with the size and morphology of the prepared n...     

红外吸收光谱（NDIR）检测混合气体中二甲醚含量分析法

利用非分光红外吸收光谱法（NDIR）,采用中红外光源（波长：2．5—25μm）和主要包括样品气气阻、样品泵、红外吸收池和电路模块技术建立了混合气体中二甲醚气体成分光谱检测系统,并使用该系统对混合气体中的二甲醚气体成分进行了测量,得到了1．0×10^-2的检测灵敏度。整个光谱检测系统具有很好的光谱分辨率、选择性以及测量灵敏度,适用于各种混合气体中二甲醚气体成分的检测。     

The Use of Gas-Phase UV Spectra in the 168-330-nm Wavelength Region for Analytical Purposes. 1. Qualitative Measurements

A novel instrument, which combines gas chromatographic separation with ultraviolet detection, has been employed in the qualitative study of molecular UV absorption spectra in the gas phase. The wavelength range available with the current instrument made studies in the region of 168-330 nm possible. The absorption spectra between 168 and 330 nm for ～1000 organic compounds and a number of inorganic gases were registered. For all the spectra recorded, 69% showed absorption maxima shorter than 190 nm, and as much as 87% shorter than 200 nm. This indicates the importance of the short UV wavelength region for analytical purposes. The results showed that each compound studied gave rise to unique absorption spectra. The influence of temperature on the shape of the spectra was studied in the range of 15-205 °C. A slight broadening effect on spectral absorption bands (0.3 nm) and the vibrational structure (maximally 1.4 nm) with increased temperature was observed. However, this effect was shown to have no influence on the analytical results. In the vast majority of cases, where structural isomers were investigated, there were clear differences between the recorded spectra. Compounds with the same functional group showed pronounced similarities. The influence of conjugation and various substituents could be demonstrated. A commercial computer program was used for a computer search of unknowns against the recorded reference spectra. This showed that the gas-phase UV spectra are very well defined and that a search always resulted in a very close agreement, even if concentrations and chromatographic conditions were different between the recording of reference and unknown. When a search was performed on a compound not present in the library, the result pointed out the correct class of compounds.     

Complexation of Be(II) Ion with 1-(2,4-Dihydroxy-1-phenylazo)-8-hydroxy-3,6-naphthalenedisulfonate as the Chemical Basis of the Selective Detection of Ultratrace Be by Reversed-Phase High-Performance Liquid Chromatography

The complexation reactions of beryllium(II) ion with 1-(2,4-dihydroxy-1-phenylazo)-8-hydroxy-3,6-naphthalenedisulfonate (H-resorcinol) are studied. The acid dissociation constants of H-resorcinol, H(3)L(2-), at 293 K and I = 0.10 [K(OH, NO(3))] are pK(a)((1)) = 5.67, pK(a)((2)) = 8.57, and pK(a)((3)) > 13. The formation constant at 293 K and I = 0.10 [(K,H)NO(3)] is estimated to be log[{[Be(HL)(2-)][H(+)](2)}/{[Be][H(3)L(2-)]}] = -4.58, and pK(a)' = 6.39 for [Be(HL)](2-), which give the basis for the optimization of the precolumn chelation reactions and the masking system with EDTA. The kinetic data for ligand substitution reactions with sulfosalicylate ion are also reported to demonstrate the remarkable inertness of the Be chelate, which is suitable for HPLC separation. Reported is an accurate method for determining traces of Be(II) ion at nanomolar levels with photometric detection coupled with ion-pair reversed-phase HPLC. The chelate, [Be(II)L](3-), is efficiently separated on an Asahipak ODP-50 column using tetrabutylammonium bromide as an ion-pairing agent in a methanol (35 wt %)-water eluent. Only Al and Fe give peaks under the conditions used. The large molar absorptivity of the H-resorcinol chelate, 3.99 × 10(4) M(-1) cm(-1) at 500 nm, and the short retention time with excellent peak resolution ensure the ultralow detection limit (3σ blank) down to 7.2 ppt (0.8 nM) with no preconcentration procedures. The excellent toughness toward the matrix influence was demonstrated using the model solution for an air-dust sample. The HPLC separation, coupled with the EDTA masking procedure, enables one to detect Be(II) ion at 20 nM in the presence of metals at the natural abundance levels in air samples, such as Al, Fe, Ca, Mg, Zn, and Pb at 240, 140, 300, 66, 16, and 6.2 μM, respectively, in the final solution.     

聚丙烯酸包囊的1-(羧甲基)-1,2,3-三唑-4-羧酸稳定胶体金对Al^3+的可视化检测

以1-(羧甲基)-1,2,3-三唑-4-羧酸(FG)作为配体制备了形貌可控、粒径分布均匀的胶体金溶液,在胶体金溶液中加入适量聚丙烯酸(PAA)聚合物实现PAA对胶体金的包囊。利用紫外可见分光光度计、透射电镜、红外光谱等分析测试手段对胶体金进行了全面表征。实验表明,1-(羧甲基)-1,2,3-三唑-4-羧酸稳定的胶体金(FG-AuNPs)对Al^3+具有良好的选择性,可以实现对Al^3+的可视化快速检测,其肉眼最低检测限达1μmol/L。机理研究表明,Al^3+与1-(羧甲基)-1,2,3-三唑-4-羧酸配体具有选择性的配位作用,通过配位作用诱导胶体金的聚集实现其快速检测的目的。在FG-AuNPs溶液中加入PAA可以提高FG-AuNPs的稳定性和对铅离子的容忍度,在其他重金属离子是高浓度的情况下提升了对Al^3+的特异性选择。     

Extension of fourier transform vibrational circular dichroism into the near-infrared region: continuous spectral coverage from 800 to 10 000 cm(-1)

We report the first vibrational circular dichroism (VCD) spectra with continuous coverage from 800 cm(-1) in the mid-infrared (MIR) region to 10 000 cm(-1) in the near-infrared (NIR) region. This coverage is illustrated with MIR and NIR absorbance and VCD spectra of 2,2-dimethyl-dioxolane-4-methanol (DDM), alpha-pinene, and camphor that serve as calibration samples over this entire region. Commercially available, dual-source Fourier transform (FT) MIR and NIR VCD spectrometers were equipped with appropriate light sources, optics, and detectors, and were modified for dual-polarization-modulation (DPM) operation. The combination of liquid-nitrogen- and thermoelectric-cooled HgCdTe (MCT) detectors, as well as InGaAs and Germanium (Ge) detectors operating at room temperature, permitted collection of the desired absorbance and VCD spectra across the range of vibrational fundamental, combination band, and overtone frequencies. The spectra of DDM and alpha-pinene were measured as neat liquids and recorded for both enantiomers in the various spectral regions. Spectra for camphor were all measured in CCl(4) solution at a concentration of 0.6 M, except for the carbonyl-stretching region, where a more dilute concentration was used. The typical anisotropy ratios (g) of the three molecules were estimated with respect to their strongest VCD bands in each spectral region. It was found that for all three molecules in the spectral regions above 2000 cm(-1), anisotropy ratios are approximately the same order (10(-5)) of magnitude. However, in the MIR region, the typical anisotropy ratios are significantly different for the three molecules. This study demonstrates that with modern FT-VCD spectrometers modified for DPM operation, VCD spectra can be measured continuously across a wide spectral range from the MIR to nearly the visible region with an unsurpassed combination of signal-to-noise ratio and spectral resolution.     

Signatures of Electron-Electron Correlations in the Optical Spectra of α-(BEDT-TTF)2 MHg(SCN)4 (M=NH4 and Rb)

We interpret the optical spectra of α-(BEDT-TTF)₂MHg(SCN)₄ (M=NH₄ and Rb) in terms of a 1/4 filled metallic system close to charge ordering and show that in the conductivity spectra of these compounds a fraction of the spectral weight is shifted from the Drude-peak to higher frequencies due to strong electronic correlations. Analyzing the temperature dependence of the electronic parameters, we distinguish between different aspects of the influence of electronic correlations on optical properties. We conclude, that the correlation effects are slightly weaker in the NH₄ compound compared to the Rb one.     

Cloud Detection and Clearing for the Earth Observing System Terra Satellite Measurements of Pollution in the Troposphere (MOPITT) Experiment

The Measurements of Pollution in the Troposphere (MOPITT) instrument, which was launched aboard the Earth Observing System (EOS) Terra spacecraft on 18 December 1999, is designed to measure tropospheric CO and CH(4) by use of a nadir-viewing geometry. The measurements are taken at 4.7 mum in the thermal emission and absorption for the CO mixing ratio profile retrieval and at 2.3 and 2.2 mum in the reflected solar region for the total CO column amount and CH(4) column amount retrieval, respectively. To achieve the required measurement accuracy, it is critical to identify and remove cloud contamination in the radiometric signals. We describe an algorithm to detect cloudy pixels, to reconstruct clear column radiance for pixels with partial cloud covers, and to estimate equivalent cloud top height for overcast conditions to allow CO profile retrievals above clouds. The MOPITT channel radiances, as well as the first-guess calculations, are simulated with a fast forward model with input atmospheric profiles from ancillary data sets. The precision of the retrieved CO profiles and total column amounts in cloudy atmospheres is within the expected ?10% range. Validations of the cloud-detecting thresholds with the moderate-resolution imaging spectroradiometer airborne simulator data and MOPITT airborne test radiometer measurements were performed. The validation results showed that the MOPITT cloud detection thresholds work well for scenes covered with more than 5-10% cloud cover if the uncertainties in the model input profiles are less than 2 K for temperature, 10% for water vapor, and 5% for CO and CH(4).     

Subpicogram per milliliter determination of the tobacco-specific carcinogen metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in human urine using liquid chromatography-tandem mass spectrometry

Exposure to secondhand tobacco smoke (SHS) has been linked to increased risk for a number of diseases, including lung cancer. The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is of particular interest due to its potency and its specificity in producing lung tumors in animals. The NNK metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine is frequently used as a biomarker for exposure. Due to its long half-life (40-45 days), NNAL may provide a long-term, time-averaged measure of exposure. We developed a highly sensitive liquid chromatography-tandem mass spectrometry method for determination of NNAL in human urine. The method involves liquid-liquid extraction followed by conversion to the hexanoate ester derivative. This derivative facilitates separation from interfering urinary constituents by extraction and chromatography and enhances detection with electrospray ionization mass spectrometry. The lower limit of quantitation is 0.25 pg/mL for 5-mL urine specimens. Applications to studies of people with a range of different SHS exposure levels is described.     

Update of line parameters of ozone in the 2550-2900 cm(-1) region

An update of spectroscopic line parameters for the 3.45-3.92 microm ozone bands is reported. The line list includes the parameters of 15 bands of the main isotopic species and of the v1+v2+v3 band of 16O16O18O and 16O18O16O. The results are based on previous high resolution laboratory studies. Comparisons of experimental spectra with an absorptance simulation of ozone based on the reported line list shows that the latter one is accurate enough for strong, medium, and weak transmittance in the 2550-2900 cm(-1) spectral range. The data are available on the Web in the Spectroscopy and Molecular Properties of Ozone (S&MPO, http://smpo.iao.ru and http://ozone.univ-reims.fr) and HITRAN (http://cfa-www.harvard.edu/hitran/) databanks.     

Analysis of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in urine by extraction on a molecularly imprinted polymer column and liquid chromatography/atmospheric pressure ionization tandem mass spectrometry

The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is present in the urine of tobacco users and, at lower concentrations, in the urine of nonsmokers exposed to secondhand smoke. NNAL is a valuable biomarker of human exposure to the carcinogenic nitrosamines in tobacco and tobacco smoke, but its presence at low concentrations in urine requires sensitive and often complex analytic procedures. In this report, we describe the development of an efficient method for the analysis of NNAL in human urine using liquid chromatography/atmospheric pressure ionization tandem mass spectrometry (LC/MS/MS) combined with a novel sample cleanup based on a molecularly imprinted polymer (MIP) column developed specifically for this assay. Our results suggest that this combination of MIP column extraction and LC/MS/MS can provide a sensitive and relatively simple analytical method suitable for application to epidemiologic investigations of health risks associated with the exposure to tobacco smoke or SHS in both smokers and nonsmokers.     

New Approach for the Surface Enhanced Resonance Raman Scattering (SERRS) Detection of Dopamine at Picomolar (pM) Levels in the Presence of Ascorbic Acid

The development of a novel surface-enhanced resonance Raman scattering (SERRS) platform that allows fast and sensitive detection of dopamine (DA) has been reported. The iron-nitrilotriacetic acid attached silver nanoparticle (Ag-Fe(NTA)) substrate provides remarkable sensitivity and reliable repeatability. The advantages of both the surface functionalization for specific analytes and the SERRS are integrated into a single functional unit. While the silver core gives the necessary enhancing properties, the Fe-NTA receptors can trap DA adjacent the silver core and the NTA-Fe-DA complex formed provides resonance enhancement with a 632.8 nm laser. DA could be detected in pM level without any pretreatment with a reliable discrimination against AA, by utilizing low laser power (10 mW) and short data acquisition time (10 s). The high sensitivity along with the improved selectivity of this sensing approach is a significant step toward molecular diagnosis of Parkinson's disease.     

Lambert absorption coefficients of water in the frequency range of 3000-934 cm(-1)

Accurate values for the Lambert absorption coefficients of water have been determined in the atmospherically important frequency region of 3000-934 cm(-1) (3.333-10.707 μm). These values were calculated at every 2 wave numbers from linear regression of 13 spectra obtained by using both transmission and internal reflection techniques with varying sample thicknesses. Correlation coefficients (R(2)) varied from 0.998 to 0.826 and estimated errors in the measured values ranged from 1% to 10%. Results are compared with those reported earlier from single measurements.     

The use of silver(I)-2-[2-(2-methoxyethoxy)ethoxy]acetate as precursor in the deposition of thin silver layers on float glass by the atmospheric pressure combustion chemical vapor deposition process

The innovative use of silver(I)-2-[2-(2-methoxyethoxy)ethoxy]acetate ([AgO₂C(CH₂OCH₂)₃H], 3) as precursor for the deposition of silver on float glass by applying the atmospheric pressure combustion chemical vapor deposition process is described. As nucleation layer tungsten oxide was utilized, conformal, closed and dense silver layers of ca. 70 nm thickness were obtained. They are adhesive and high reflective with a resistivity of 5 ? 10⁻⁸ Ωm.