Integrated Intensity Measurements Research Articles

Measuring the infrared intensity of a close-up resolved target with close-up blackbody references

The intensity of objects in the infrared is an important quantity for a number of applications. Intensity in watts per steradian is the parameter that is used to describe either small targets or targets that are far away. Intensity is used because these cases are usually presented to a detection sensor where the object is smaller than the sensor detector angular subtense, a situation known as an “unresolved target.” In the military, unresolved targets can be rocket-propelled grenades, man-portable air defense threats, enemy aircraft at long range, or even ground vehicles that are being engaged by ground-to-ground or air-to-ground missiles. Typical “resolved target” metrics such as root-sum-squared differential temperature do not work well for unresolved targets. In addition, a given target intensity coupled with range, atmospheric transmission, and sensor noise equivalent irradiance can provide a quick signal-to-noise estimate of a particular sensor against a particular target. Target intensity can even be a measure of how visible ones platform is to other sensor and can be used to reduce platform signatures. Measurement of intensity is always a difficult procedure, where there is typically a sensor that does not encompass all aspects of measurement parameters. For example, there are very few radiometers that include high-resolution spatial measurements with high-resolution spectral measurements with high-resolution temporal measurements, not to mention polarization. For the few systems that exist that can provide a simultaneous measurement with most of these parameters, the cost is prohibitive. Usually, a spectral radiometer will provide high spectral resolution with no spatial information and a slow temporal rate. These measurements are common. In the case we describe here, the intensity measurement is taken broadband in the midwave or longwave infrared regions with good spatial resolution. This measurement provides a band integrated intensity measurement. We describe an approach for sensor calibration and object intensity measurement that can be used for broadband sensors applications.

New approach for wine authenticity screening by a cumulative 1H and 2H qNMR

New methodological approach for rapid control of wine authenticity without sample preparation, based on the quantitative NMR spectroscopy (qNMR) of the protium 1H and deuterium 2H nucleus is suggested. The content of dominant (e.g. water, ethanol) and some minor (e.g. glycerol, organic acids) components of wine are determined from qNMR 1H spectra for authentication of molecular composition. The sum of all exchanging hydrogen atoms of wine's components provide the 1H signal with a chemical shift of 4.8 ppm. Accounting for their content from 1H spectrum allows us calculate the 2H isotopic content in wine water from integral intensity of corresponding signal in the 2H qNMR spectrum using an internal or external standard with a known content of the 2H isotope. The possible addition of water can be found from comparison of this value with values of surface and/or ground waters from corresponding viticulture areas. This approach was used for white and red wines from the Black Sea region (Krasnodar area & Crimea peninsula). The 2H contents in investigated wines range from 157 to 165 ppm. The maximum 2H isotope content in surface waters does not exceed 148 ppm. A qNMR measurement of wine according to the proposed approach takes some minutes, that significantly exceeds the laboriousness of methods based on IRMS/SIRA (e.g. δ13C, δ18O). The error of qNMR measurements is less than 2.0%. The qNMR screening of deuterium (2H) in ethanol can be used for detection of possible wine chaptalization. This approach is similar to the known SNIF-NMR method. The positive difference with this method is the use of minimal quantity of enriched 2H standard and measurement of integral intensities of all signals instead of heights. It allows to reduce measurements' time as well as to measure the 2H content of all fragments of ethanol molecules – CH3−, CH2−, OH-groups. The publication has been prepared with the support of the “RUDN University Program 5–100”.

Selection of the optimal combination of water vapor absorption lines for detection of temperature in combustion zones of mixing supersonic gas flows by diode laser absorption spectrometry

Determination of a gas medium temperature by diode laser absorption spectrometry (DLAS) is based on the measurement of integral intensities of the absorption lines of a test molecule (generally water vapor molecule). In case of local thermodynamic equilibrium temperature is inferred from the ratio of the integral intensities of two lines with different low energy levels. For the total gas pressure above 1 atm the absorption lines are broadened and one cannot find isolated well resolved water vapor absorption lines within relatively narrow spectral interval of fast diode laser (DL) tuning range (about 3 cm −1 ). For diagnostics of a gas object in the case of high temperature and pressure DLAS technique can be realized with two diode lasers working in different spectral regions with strong absorption lines. In such situation the criteria of the optimal line selection differs significantly from the case of narrow lines. These criteria are discussed in our work. The software for selection the optimal spectral regions using the HITRAN-2012 and HITEMP data bases is developed. The program selects spectral regions of DL tuning, minimizing the error of temperature determination δТ/T , basing on the attainable experimental error of line intensity measurement δS . Two combinations of optimal spectral regions were selected – (1.392 & 1.343 μm) and (1.392 & 1.339 μm). Different algorithms of experimental data processing are discussed.

How to Calculate Molecular Column Density

The calculation of the molecular column density from molecular spectral (rotational or ro-vibrational) transition measurements is one of the most basic quantities derived from molecular spectroscopy. Starting from first principles where we describe the basic physics behind the radiative and collisional excitation of molecules and the radiative transfer of their emission, we derive a general expression for the molecular column density. As the calculation of the molecular column density involves a knowledge of the molecular energy level degeneracies, rotational partition functions, dipole moment matrix elements, and line strengths, we include generalized derivations of these molecule-specific quantities. Given that approximations to the column density equation are often useful, we explore the optically thin, optically thick, and low-frequency limits to our derived general molecular column density relation. We also evaluate the limitations of the common assumption that the molecular excitation temperature is constant and address the distinction between beam-averaged and source-averaged column densities. As non-LTE approaches to the calculation of molecular spectral line column density have become quite common, we summarize non-LTE models that calculate molecular cloud volume densities, kinetic temperatures, and molecular column densities. We conclude our discussion of the molecular column density with worked examples for C18O, C17O, N2H+, NH3, and H2CO. Ancillary information on some subtleties involving line profile functions, conversion between integrated flux and brightness temperature, the calculation of the uncertainty associated with an integrated intensity measurement, the calculation of spectral line optical depth using hyperfine or isotopologue measurements, the calculation of the kinetic temperature from a symmetric molecule excitation temperature measurement, and relative hyperfine intensity calculations for NH3 are presented in appendices. The intent of this document is to provide a reference for researchers studying astrophysical molecular spectroscopic measurements.

Fast Modulation of μ-Opioid Receptor (MOR) Recycling Is Mediated by Receptor Agonists

The μ-opioid receptor (MOR) is a member of the G protein-coupled receptor family and the main target of endogenous opioid neuropeptides and morphine. Upon activation by ligands, MORs are rapidly internalized via clathrin-coated pits in heterologous cells and dissociated striatal neurons. After initial endocytosis, resensitized receptors recycle back to the cell surface by vesicular delivery for subsequent cycles of activation. MOR trafficking has been linked to opioid tolerance after acute exposure to agonist, but it is also involved in the resensitization process. Several studies describe the regulation and mechanism of MOR endocytosis, but little is known about the recycling of resensitized receptors to the cell surface. To study this process, we induced internalization of MOR with [D-Ala(2), N-Me-Phe(4), Gly(5)-ol]-enkephalin (DAMGO) and morphine and imaged in real time single vesicles recycling receptors to the cell surface. We determined single vesicle recycling kinetics and the number of receptors contained in them. Then we demonstrated that rapid vesicular delivery of recycling MORs to the cell surface was mediated by the actin-microtubule cytoskeleton. Recycling was also dependent on Rab4, Rab11, and the Ca(2+)-sensitive motor protein myosin Vb. Finally, we showed that recycling is acutely modulated by the presence of agonists and the levels of cAMP. Our work identifies a novel trafficking mechanism that increases the number of cell surface MORs during acute agonist exposure, effectively reducing the development of opioid tolerance.

Weak ferromagnetism and magnetic phase transitions in Gd2CuO4

We report a polarized neutron study of the magnetic structures and phase transitions in Gd${}_{2}$CuO${}_{4}$ in low magnetic fields. These experiments have been complemented by integrated intensity measurements with unpolarized neutrons in zero field. Polarized neutron flipping ratio measurements have been made with magnetic fields $H=0.05$, $0.10$, and 0.5 T in the temperature range 4--20 K. These have enabled us to deduce that the anomalous temperature behavior of the coherent magnetic scattering from the Cu sublattice, which shows sharp intensity minima at $T$${}_{\mathrm{C}1}$ $\ensuremath{\approx}18$ K and $T$${}_{\mathrm{C}2}$ $\ensuremath{\approx}8$ K, is due to cross overs in the sign of the interaction between strongly coupled, weakly ferromagnetic, CuO${}_{2}$ layers. At $T$${}_{\mathrm{C}1}$ the coupling changes from ferromagnetic to antiferromagnetic and long-range order between layers is temporarily lost. $T$${}_{\mathrm{C}2}$ is the temperature at which the Gd moments order and a further reorganization of the interlayer order takes place. The weak ferromagnetism of the CuO layers is found to be due to a small rotation of the Cu moments in the same direction as that in which their coordinating oxygen squares rotate in the tetragonal to orthorhombic distortion of the crystal structure. Further analysis of the flipping ratio measurements has enabled us to model the magnetic structures of the zero-field and the field-induced phases of Gd${}_{2}$CuO${}_{4}$.

Determination of the magnetic structures of the field-induced phases ofHoMnO3

We have determined the magnetic structure of the field-induced phases of the multiferroic hexagonal manganite $\mathrm{Ho}\mathrm{Mn}{\mathrm{O}}_{3}$ by combining integrated intensity data, collected with unpolarized neutrons on a single crystal, with measurements of the polarization dependence of the intensities of the diffraction peaks from the same crystal. The present investigation shows that the magnetic structure of $\mathrm{Ho}\mathrm{Mn}{\mathrm{O}}_{3}$ changes, apparently nearly continuously, with increasing field from the zero field antiferromagnetic (AF1) phase $(P{6}_{3}^{\ensuremath{'}}c{m}^{\ensuremath{'}})$ to a ferromagnetic (F2) phase $(P{6}_{3}{c}^{\ensuremath{'}}{m}^{\ensuremath{'}})$ in which the triangular configuration of Mn moments in the (001) plane is maintained. There is also a significant variation with field in the ordered moments of Ho2 and Mn in the AF1 and F2 phases, respectively. We show that the structures of the field-induced phases cannot be determined completely from the integrated intensity measurements alone.

New infrared integrated band intensities for HC 3N and extensive line list for the ν5 and ν6 bending modes

The infrared spectrum of cyanoacetylene (also called propynenitrile) has been investigated from 400 to 4000 cm −1 at a resolution of 0.5 cm −1. Integrated intensities of the main bands and a number of weaker bands have been obtained with an uncertainty better than 5%. Inaccurate values in previous studies have been identified in particular concerning the intensity of the strong ν 5 stretching band at 663.2 cm −1. Former results on the temperature dependence of integrated intensities have also been revisited. Synthetic spectra calculation has been performed for the ν 5 and ν 6 bands on the basis of the best available high resolution data. It has been shown that the GEISA line parameters for HC 3N are not sufficient to reproduce the band intensities and some hot band features observed in our experimental spectra at room temperature. As a first step, the model spectra has been improved by including a number of missing hot subbands and by calculating accurately the hot band relative intensities. Finally, a perfect agreement between calculated and observed spectra was achieved on the basis of a global analysis of HC 3N levels up to 2000 cm −1 combined with the new integrated intensity measurements. A new extensive line list for the ν 5 and ν 6 bending modes of HC 3N has been compiled.

Thin film composition determination by means of integrated intensity measurements

A new method based on measurement of the absorption of an x-ray beam diffracted from a substrate has been used to determine the film composition in an InGaAs/InP nearly-lattice-matched single heterostructure.The absorption coefficient, μInGaAs, of the InGaAs alloy was obtained by accurately measuring the InGaAs layer thickness and the integrated intensities of several diffractions of the InP substrate compared with the integrated intensities of the equivalent peaks of an InP reference crystal. By using the tabulated Ga, As and In absorption factors, the In content was then determined. It is shown that in the case of an InGaAs alloy the accuracy in In content determination can reach 1%. The absolute In content of the InGaAs epilayer was found to be 4%–5% larger than expected from the linear dependence of the lattice parameter on the alloy composition as stated by the Vegard law.This result has been confirmed by a diffraction profile auto-fitting software; with the assumption of the Vegard law the best fit of the 004 diffraction profile of the InGaAs/InP heterostructure could only be obtained with a 4.6% larger InGaAs thickness, to compensate for the larger In content as determined by the absorption measurement.

The determination of the spectral turnover in faint Compact Steep-Spectrum radio sources using the VLA at 74 MHz

We carried out VLA observations in A configuration at 74 MHz of a new sample of faint Compact Steep-Spectrum (CSS) radio sources as part of a comprehensive project to study the nature and evolution of peaked-spectrum radio sources. In conjunction with higher frequency spectral information this has enabled us to determine the peak frequency and peak flux density of the spectral turnover for 35 faint CSS radio sources. Spectra are presented. An analysis is given of the quality of the images and their suitability for integrated intensity measurements of the CSS radio sources.

Magnetic structure ofGdAgSb2determined by x-ray resonant exchange scattering

X-ray resonant exchange-scattering experiments were performed on a single crystal of ${\mathrm{GdAgSb}}_{2}$ to determine the magnetic structure. Long-range antiferromagnetic ordering, characterized by a wave vector of $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\tau}}=(\frac{1}{2}00),$ develops below the N\'eel temperature ${(T}_{N}=13 \mathrm{K}),$ consistent with the dc susceptibility measurements. For the scattering geometry employed in these measurements, the resonant enhancement at the $(\frac{1}{2}08)$ magnetic peak arises from electric quadrupole transitions only while the resonant enhancement at the $(0\ensuremath{-}\frac{1}{2}8)$ magnetic peak arises from electric dipole transitions. Q-dependent integrated intensity measurements were carried out, along with polarization analysis of the scattered beam, and demonstrated that the moments lie in the tetragonal basal plane and are perpendicular to the magnetic wave vector.

Molecular electronic branching ratios of CaI(A2Π1/2,3/2,B2Σ+) resulting from the reaction of Ca[4s4p(3PJ)] with CH3I following the pulsed dye-laser excitation of atomic calcium

Molecular electronic branching ratios to yield CaI(A2Π1/2), CaI(A2Π3/2) and CaI(B2Σ+) have been determined following the reaction of Ca[4s4p(3PJ)], 1.888 eV above the 4s2(1S0) ground state, with CH3I. These were determined from the combination of time-dependence and calibrated integrated intensity measurements of the atomic resonance fluorescence from Ca(43P1 → 41S0) and the molecular chemiluminescence from CaI(A2Π1/2,A2Π3/2,B2Σ+ → ×2Σ+) following pulsed dye-laser generation of Ca(43P1). The results were found to be as follows: A1/2 (2.7 ± 1.1) × 10−3, A3/2 (2.6 ± 1.3) × 10−3 and B, (2.0 ± 0.8) × 10−3.

Error analysis of infrared transmission measurements: determination of baseline, choice of peak maximum and range truncation in band profile and integrated intensity determination

The problems of baseline determination, of the choice of band height and of the truncation of band wings are analysed for the cases of band profile analysis and of the integrated intensity measurements taking the Lorentzian and Gaussian bands as models.

Layer Charge Estimation of Smectites Using Infrared Spectroscopy

A new method of measuring the layer charge of smectites by IR spectroscopy is proposed based on the integrated intensity measurement of the band assigned to the ammonium fundamental upsilon 4 mode of NH (super +) 4 -exchanged clays. Measurements are made before and after Li fixation (Hofman & Klemen effect). These allow the quantitative determination of the total charge, equivalent to CEC, and tetrahedral and octahedral charge distribution in both dioctahedral and trioctahedral smectites.

The structure and magnetic moment distribution in the antiferromagnetic phase of

The antiferromagnetic structure of the intermetallic compound has been determined from neutron polarimetric measurements and refined by combining these data with integrated intensity measurements. The structure was found to be non-collinear with the U moments confined to the a - b plane. The moments of U atoms in each of the two sets of sixfold sites are arranged hexagonally with rotations of between them and the two sets are rotated with respect to one another by . The third (twofold) set of U atoms has no ordered moment. These conclusions are in disagreement with a previous determination of the structure from powder data which gave a collinear structure with moments parallel to the c axis. Magnetization measurements made on single crystals in the temperature range 300 - 2 K can be understood in terms of a transition to a non-collinear easy plane antiferromagnetic structure stable below 22 K. Polarized neutron measurements have been used to determine the contribution of each of the U sites to the susceptibility between 22 and 2 K. These show that of the two sixfold U sites, that with the smaller ordered moment contributes more than half of the total susceptibility. The twofold site, which is characterized by a small U - U separation, makes the smallest contribution.

Textural changes during thermomechanical processing of Ti-24Al-11Nb alloy

An alloy with the composition Ti-24Al-11Nb is a typical representative of two phase material with the structures {alpha}{sub 2} (based on Ti{sub 3}Al) and {beta} (B2) (disordered or ordered b.c.c.), which exhibits room temperature ductility. The study of texture of such an alloy has received relatively less attention in spite of the fact that application of these alloys in sheet form have been envisaged. Limited investigations carried out by Hon et al. deals with the study of basal textures on hot rolling of the Ti-24Al-10Nb alloy strip. Knorr et al. examined the effect of heat treatment on texture development in a hot rolled Ti-24Al-11Nb alloy. However, no systematic information is available on textural changes during hot rolling with respect to changes in temperature and strain. The present study is aimed at examining the textural changes during thermomechanical processing which involve hot rolling at different temperatures and thickness reductions. The textural changes have been examined through X-ray diffraction technique employing integrated intensity measurements and from pole figures. A reasonably strong basal (0002) {alpha}{sub 2} texture can be produced in Ti-24Al-11Nb alloy by heavily deforming primary {alpha}{sub 2} phase at 1,173 K. On the other hand, a same amount of deformation at more » 1,373 K leads to weakening of the basal texture. « less

Study of point defect clusters in high purity single crystals of silicon grown by Czochralski and float-zone methods by diffuse X-ray scattering technique

Results of study of point defect clusters in high purity ( ∼ 10 kΩ · cm ) dislocation-free Czochralski (Cz) and float-zone (FZ) grown crystals (∼ 50 mm diameter, 11 mm thick, p-type) are reported. A multicrystal X-ray diffractometer set in (+, −, −, +) geometry and employing a well-collimated Mo K α 1 beam was used. High resolution X-ray diffractometry, absolute integrated intensity measurements and diffuse X-ray scattering (DXS) measurements were carried out. The specimens gave sharp diffraction curves and the integrated intensities were found to be close to the theoretical value for an ideally perfect silicon crystal. DXS measurements were made around 111 reciprocal lattice point (RLP) along four directions of K ∗ : [111], [1̄1̄1̄], [01̄1] and [011̄]. K ∗ is the vector which connects the elemental reciprocal volume under investigation with the nearest RLP. From the analysis of the DXS intensity versus K ∗ plots, it was found that the source of DXS is interstitial defect clusters in Cz-grown crystals and vacancy defect clusters in FZ-grown crystals. By using a phenomenological model, the values of cluster size R cl, cluster volume A cl and number of defects per cluster N cl, respectively, were found to be: 0.8 μm, 2.02 × 10 −16 cm 3, 1.26 × 10 6 for Cz specimen and 0.6 μm, 1.32 × 10 −16 cm 3, 8.3 × 10 5 for the FZ specimen.

Antiferromagnetism in Mn5Si3: the magnetic structure of the AF2 phase at 70 K

The antiferromagnetic structure of the AF2 phase of Mn5Si3, stable between the Neel point at 99 K and the transition to a second antiferromagnetic AF1 phase at 66 K, has been determined from unpolarized neutron integrated intensity measurements on single-crystal and powder samples. The paramagnetic phase adopts the hexagonal D88 structure, Z=2, with Mn1 and Mn2 atoms in a fourfold and a sixfold site respectively. With the onset of long-range magnetic order the symmetry is reduced to orthorhombic. The orthorhombic cell dimensions at 70 K are a=6.89856(1), b=11.89120(2) and c=4.79330(1) A and these are related to those of the hexagonal cell, ah etc., by a approximately=ah, b approximately= square root 3ah and c approximately=ch. The orthorhombic cell is C-face centred, space group Ccmm, with Z=4. Magnetic reflections indexed on this cell have h+k odd corresponding to a (010) magnetic propagation vector. Zero-field neutron polarimetry on a single crystal shows that there are no components of moment parallel to the c axis. A magnetic structure in which the Mn1 and one-third of the Mn2 atoms have no ordered moment and the remaining Mn2 atoms a moment of 1.48(1) mu B directed parallel and antiparallel to b gives a good fit to both the powder and single-crystal intensities. This structure differs significantly from previous models, but it is coherent with current ideas about the stability of Mn moments in compounds with B-subgroup elements. Its relation to the recently revised structure of the low-temperature AF1 phase is discussed.

Statistical basis for the determination of optical pathlength in tissue

Here, the authors show how to derive the mean and variance of the transilluminated signal obtained in models of light propagation in tissue, based both on a stochastic Monte Carlo method and on a deterministic diffusion approximation. The theoretical treatment of the Monte Carlo model applies only to integrated intensity measurements, whereas the diffusion approximation gives an estimator for the time-dependent case as well. The authors present results that show the accurate prediction of Monte Carlo statistics, and propose that the diffusion approximation is therefore a suitable mechanism for incorporating noise into modelling procedures.

Mass Diffusion Transport Studies of Lithium Sulfate in Aqueous Solutions Using Raman Spectroscopy

The diffusivity coefficients of lithium sulfate solutions in water and water and silica gels over the concentration range 0.2 to 2.5 molal have been measured for the first time with micro-Raman spectroscopy for a horizontal-tube capillary, conventional 90° Raman scattering for a narrow-bore vertical-tube system, and FT-Raman spectroscopy for the gels. Data were obtained for axial concentration profiles as function of the distance and for time elapse at fixed positions on the tube axis with the use of integrated intensity measurements of the v1 (SO4) symmetric stretching band at 980 cm−1. The use of computer model calculations to fit the experimental data yielded values of DA = 0.4 × 10−5 cm2 s−1 for the vertical system and 0.3 × 10−5 cm−2 s−1 for the gel system. Discrepancies observed for the horizontal system have been ascribed to the presence of convective flow. A convective flow rate of 5.10−2 cm h−1 was calculated in this case with the use of computer simulation and used in the fitting of the experimental data through a general form of the second Fick's law. Under these conditions, a DA value of 0.2 × 10−5 cm2 s−1 was obtained.