Line Intensities Research Articles

Determination of S, Ni, Cu in copper-nickel sulfide ores by total reflection X-ray fluorescence analysis: experience of participation in the interlaboratory comparisons

The quality of the determination of S, Ni, Cu in copper-nickel sulfide ores was assessed in the framework of the program for interlaboratory comparative tests (ICT) using total reflection X-ray fluorescence analysis (TXRF) taking into account the criteria for methods for determining the chemical composition of mineral raw materials. Certified TXRF techniques for the analysis of mineral materials are absent, so the interlaboratory comparison test was used to control and improve the accuracy of measurements by TXRF. Powdered ore samples were prepared as suspensions by wet grinding: 100 mg of the powder, 4 ml of ultra-pure water and 250 μl of the Ga standard solution were milled using 20 g of ZrO2 balls 1 mm in diameter in the mixing mill for 10 minutes at a frequency of 20 Hz. The ratio of the intensities of the characteristic lines of the analyzed elements and the Ga internal standard was chosen as an analytical signal. To plot calibration curves, a set of ore reference samples was analyzed using certified procedures (atomic absorption spectrometry for Cu, Ni, gravimetry for S). The quality of the TXRF analysis was assessed by the value of Z-criterion. The measurement error did not exceed 5 rel. %. The relative percentage differences between the TXRF results and the results obtained in the interlaboratory study was less than 10%. The described method can be used for rapid analysis of copper-nickel sulfide ores.

Surface hardness imaging of a low-alloy steel using laser-induced breakdown spectroscopy

Conventional tactile hardness testing methods such as Brinell, Rockwell or Vickers rely on direct mechanical contact, which results in significant surface damage and prohibits their application to complex specimen geometries. Furthermore, the sample must have a certain thickness for tactile testing methods to be applied. In this work, we investigated the use of laser-induced breakdown spectroscopy as a fast non-quantitative alternative for visualizing surface hardness gradients. To eliminate the influence of different chemical compositions, we manually heat-treated low-alloy steel pieces cut from the same raw material and batch. By partially quenching a sample piece, we were able to obtain a hardness gradient along the longitudinal axis. We found a positive correlation between the ratio of ionic to atomic line intensities of iron (I Fe II 263.1 nm / I Fe I 358.1 nm) and the mechanical hardness of the sample surface. By scanning the surface and measuring the line intensity ratios, we were able to obtain a spatially resolved map directly correlating with the surface hardness distribution. Additionally, it was observed that the irradiation of laser pulses resulted in significant surface alterations, thereby invalidating subsequent measurements and scans at identical positions.

Exploring the viability of combined laser-induced breakdown spectroscopy and Raman spectroscopy for stratigraphic analysis of murals containing isomeric pigments: a case study on realgar and orpiment

A novel combined measurements techniques has been designed in this work, enabling the acquisition of laser-induced breakdown spectroscopy (LIBS) and Raman spectral signals at the same point on a sample. The application of this combined technique to the analysis of multi-layered mock-up blocks painted with orpiment and realgar pigments has yielded significant insights. By correlating variations in the emission line intensity of characteristic elements within the LIBS spectra with depth-specific Raman spectra, the number of laser pulses that penetrated the pigment layers has been accurately determined, thereby establishing a method to measure layer thickness. Finally, the technique wasto analysis the actual mural fragment from Mogao Cave 196, determining the types of pigment and the thickness of the pigment layers.Graphical

A statistical framework for recovering intensity mapping autocorrelations from cross-correlations

ABSTRACT Intensity mapping experiments will soon have surveyed large swathes of the sky, providing information about the underlying matter distribution of our early Universe. The resulting maps can be used to recover statistical information, such as the power spectrum, about the measured spectral lines (for example, H i, [C ii], and [O iii]). However precise power spectrum measurements, such as the 21 cm autocorrelation, continue to be challenged by the presence of bright foregrounds and non-trivial systematics. By cross-correlating different data sets, it may be possible to mitigate the effects of both foreground uncertainty and uncorrelated instrumental systematics. Beyond their own merit, cross-correlations could also be used to recover autocorrelation information. Such a technique has been proposed in the literature for recovering the 21 cm power spectrum. Generalizing this result, we develop a statistical framework for combining multiple cross-correlation signals in order to infer information about the corresponding autocorrelations. We do this first within the least squares estimator framework, and show how one can derive their estimator, along with several alternative estimators. We also investigate the posterior distribution of recovered autocorrelation and associated model parameters. We find that for certain noise regimes and cosmological signal modelling assumptions this procedure is effective at recovering autospectra from a set of cross-correlations. Finally, we showcase our framework in the context of several near-future line intensity mapping experiments.

Improving the Two-Color Temperature Sensing Using Machine Learning Approach: GdVO4:Sm3+ Prepared by Solution Combustion Synthesis (SCS)

The gadolinium vanadate doped with samarium (GdVO4:Sm3+) nanopowder was prepared by the solution combustion synthesis (SCS) method. After synthesis, in order to achieve full crystallinity, the material was annealed in air atmosphere at 900 °C. Phase identification in the post-annealed powder samples was performed by X-ray diffraction, and morphology was investigated by high-resolution scanning electron microscope (SEM) and transmission electron microscope (TEM). Photoluminescence characterization of emission spectrum and time resolved analysis was performed using tunable laser optical parametric oscillator excitation and streak camera. In addition to samarium emission bands, a weak broad luminescence emission band of host VO43− was also observed by the detection system. In our earlier work, we analyzed the possibility of using the host luminescence for two-color temperature sensing, improving the method by introducing the temporal dependence in line intensity ratio measurements. Here, we showed that further improvements are possible by using the machine learning approach. To facilitate the initial data assessment, we incorporated Principal Component Analysis (PCA), t-Distributed Stochastic Neighbor Embedding (t-SNE) and Uniform Manifold Approximation and Projection (UMAP) clustering of GdVO4:Sm3+ spectra at various temperatures. Good predictions of temperature were obtained using deep neural networks. Performance of the deep learning network was enhanced by data augmentation technique.

Development of a novel Cas13a/Cas12a-mediated 'one-pot' dual detection assay for genetically modified crops

IntroductionGenetically modified (GM) crops have been widely cultivated across the world and the development of rapid, ultrasensitive, visual multiplex detection platforms that are suitable for field deployment is critical for GM organism regulation. ObjectiveIn this study, we developed a novel one-pot system, termed MR-DCA (Multiplex RPA and Dual CRISPR assay), for the simultaneous detection of CaMV35S and NOS genetic targets in GM crops. This innovative approach combined Multiplex RPA (recombinase polymerase amplification) with the Dual CRISPR (clustered regularly interspaced short palindromic repeat) assay technique, to provide a streamlined and efficient method for GM crop detection. MethodsThe RPA reaction used for amplification CaMV35S and NOS targets was contained in the tube base, while the dual CRISPR enzymes were placed in the tube cap. Following centrifugation, the dual CRISPR (Cas13a/Cas12a) detection system was initiated. Fluorescence visualization was used to measure CaMV35S through the FAM channel and NOS through the HEX channel. When using lateral flow strips, CaMV35S was detected using rabbit anti-digoxin (blue line), whilst NOS was identified using anti-mouse FITC (red line). Line intensity was quantified using Image J and depicted graphically. ResultsDetection of the targets was completed in 35 min, with a limit of detection as low as 20 copies. In addition, two analysis systems were developed and they performed well in the MR-DCA assay. In an analysis of 24 blind samples from GM crops with a wide genomic range, MR-DCA gave consistent results with the quantitative PCR method, which indicated high accuracy, applicability and semi-quantitative ability. ConclusionThe development of MR-DCA represents a significant advancement in the field of GM detection, offering a rapid, sensitive and portable method for multiple target detection that can be used in resource-limited environments.

PDRs4All

Context. One of the main problems in astrochemistry is determining the amount of sulfur in volatiles and refractories in the interstellar medium. The detection of the main sulfur reservoirs (icy H2S and atomic gas) has been challenging, and estimates are based on the reliability of models to account for the abundances of species containing less than 1% of the total sulfur. The high sensitivity of the James Webb Space Telescope provides an unprecedented opportunity to estimate the sulfur abundance through the observation of the [S I] 25.249 µm line. Aims. Our aim is to determine the amount of sulfur in the ionized and warm molecular phases toward the Orion Bar as a template to investigate sulfur depletion in the transition between the ionized gas and the molecular cloud in HII regions. Methods. We used the [S III] 18.7 µm, [S IV] 10.5 µm, and [S l] 25.249 µm lines to estimate the amount of sulfur in the ionized and molecular gas along the Orion Bar. For the theoretical part, we used an upgraded version of the Meudon photodissociation region (PDR) code to model the observations. New inelastic collision rates of neutral atomic sulfur with ortho-and para- molecular hydrogen were calculated to predict the line intensities. Results. The [S III] 18.7 µm and [S IV] 10.5 µm lines are detected over the imaged region with a shallow increase (by a factor of 4) toward the HII region. This suggests that their emissions are partially coming from the Orion Veil. We estimate a moderate sulfur depletion, by a factor of ~2, in the ionized gas. The corrugated interface between the molecular and atomic phases gives rise to several edge-on dissociation fronts we refer to as DF1, DF2, and DF3. The [S l] 25.249 µm line is only detected toward DF2 and DF3, the dissociation fronts located farthest from the HII region. This is the first ever detection of the [S l] 25.249 µm line in a PDR. The detailed modeling of DF3 using the Meudon PDR code shows that the emission of the [S l] 25.249 µm line is coming from warm (>40 K) molecular gas located at AV ~1–5 mag from the ionization front. Moreover, the intensity of the [S l] 25.249 µm line is only accounted for if we assume the presence of undepleted sulfur. Conclusions. Our data show that sulfur remains undepleted along the ionic, atomic, and molecular gas in the Orion Bar. This is consistent with recent findings that suggest that sulfur depletion is low in massive star-forming regions because of the interaction of the UV photons coming from the newly formed stars with the interstellar matter.

PDRs4All

Context. Mid-infrared emission features are important probes of the properties of ionized gas and hot or warm molecular gas, which are difficult to probe at other wavelengths. The Orion Bar photodissociation region (PDR) is a bright, nearby, and frequently studied target containing large amounts of gas under these conditions. Under the “PDRs4All” Early Release Science Program for JWST, a part of the Orion Bar was observed with MIRI integral field unit (IFU) spectroscopy, and these high-sensitivity IR spectroscopic images of very high angular resolution (0.2″) provide a rich observational inventory of the mid-infrared (MIR) emission lines, while resolving the H II region, the ionization front, and multiple dissociation fronts. Aims. We list, identify, and measure the most prominent gas emission lines in the Orion Bar using the new MIRI IFU data. An initial analysis summarizes the physical conditions of the gas and demonstrates the potential of these new data and future IFU observations with JWST. Methods. The MIRI IFU mosaic spatially resolves the substructure of the PDR, its footprint cutting perpendicularly across the ionization front and three dissociation fronts. We performed an up-to-date data reduction, and extracted five spectra that represent the ionized, atomic, and molecular gas layers. We identified the observed lines through a comparison with theoretical line lists derived from atomic data and simulated PDR models. The identified species and transitions are summarized in the main table of this work, with measurements of the line intensities and central wavelengths. Results. We identified around 100 lines and report an additional 18 lines that remain unidentified. The majority consists of H I recombination lines arising from the ionized gas layer bordering the PDR. The H I line ratios are well matched by emissivity coefficients from H recombination theory, but deviate by up to 10% because of contamination by He I lines. We report the observed emission lines of various ionization stages of Ne, P, S, Cl, Ar, Fe, and Ni. We show how the Ne III/Ne II, S IV/S III, and Ar III/Ar II ratios trace the conditions in the ionized layer bordering the PDR, while Fe III/Fe II and Ni III/Ni II exhibit a different behavior, as there are significant contributions to Fe II and Ni II from the neutral PDR gas. We observe the pure-rotational H2 lines in the vibrational ground state from 0–0 S(1) to 0–0 S (8), and in the first vibrationally excited state from 1–1 S (5) to 1–1 S(9). We derive H2 excitation diagrams, and for the three observed dissociation fronts, the rotational excitation can be approximated with one thermal (~700 K) component representative of an average gas temperature, and one nonthermal component (~2700 K) probing the effect of UV pumping. We compare these results to an existing model of the Orion Bar PDR, and find that the predicted excitation matches the data qualitatively, while adjustments to the parameters of the PDR model are required to reproduce the intensity of the 0–0 S (6) to S (8) lines.

Accurate reference spectra of HD in an H2–He bath for planetary applications

Context. The hydrogen deuteride (HD) molecule is an important deuterium tracer in astrophysical studies. The atmospheres of gas giants are dominated by molecular hydrogen, and the simultaneous observation of H2 and HD lines provides reliable information on the D/H ratios on these planets. The reference spectroscopic parameters play a crucial role in such studies. Under the thermodynamic conditions encountered in these atmospheres, spectroscopic studies of HD require not only the knowledge of line intensities and positions but also accurate reference data on pressure-induced line shapes and shifts. Aims. Our aim is to provide accurate collision-induced line-shape parameters for HD lines that cover any thermodynamic conditions relevant to the atmospheres of giant planets, namely any relevant temperature, pressure, and perturbing gas composition (the H2–He mixture). Methods. We performed quantum-scattering calculations on our new, highly accurate ab initio potential energy surface (PES), and we used scattering S matrices obtained in this way to determine the collision-induced line-shape parameters. We used cavity ring-down spectroscopy to validate our theoretical methodology. Results. We report accurate collision-induced line-shape parameters for the pure rotational R(0), R(1), and R(2) lines, the most relevant HD lines for investigations of the atmospheres of the giant planets. Besides the basic Voigt-profile collisional parameters (i.e., the broadening and shift parameters), we also report their speed dependences and the complex Dicke parameter, which can influence the effective width and height of the HD lines up to almost a factor of 2 for giant planet conditions. The sub-percent-level accuracy reached in this work is a considerable improvement over previously available data. All the reported parameters (and their temperature dependences) are consistent with the HITRAN database format, hence allowing for the use of the HITRAN Application Programming Interface (HAPI) for generating the beyond-Voigt spectra of HD.

Status of edge electron density and temperature measurements with Helium Beam Emission Spectroscopy (He-BES) on EAST

Helium Beam Emission Spectroscopy (He-BES) diagnostic has been developed on EAST, which is able to measure the edge electron density and temperature profiles simultaneously using a helium line intensity ratio method. The diagnostic includes the beam injector and the detection system. There are 20 observation channels within an observation range of 80 mm in the detection system at the low filed side, which can cover the whole scrape-off layer (SOL) and part of the pedestal region of EAST. The beam injector system has been upgraded to Supersonic Molecular Beam Injector (SMBI) system to realize deeper helium injection since the 2021 campaign. Four spectral lines at wavelengths of 728.1 nm, 706.5 nm, 667.8 nm and 656.3 nm are detected by the He-BES. The first three spectral lines, including 728.1 nm, 706.5 nm, 667.8 nm, are measured for calculating edge n e and T e profiles based on the collisional-radiative model (CRM) model, and the last spectral line (656.3 nm) is used for the measurement of D α emission. The edge electrostatic fluctuations can be obtained from the power spectrum of D α emission. The electron density and temperature profiles calculated from the 667.8/728.1 and 728.1/706.5 nm line ratios are in good agreement with those from other diagnostics in the edge region of plasma. The self-consistency of He-BES diagnostic is also verified, such as the density pump out caused by LHW and the lower edge temperature caused by the lower heating power.

Determination of the azetide groups relative content in the composition of amphoteric polymer resins

The work is devoted to the determination of the relative content of azetidine groups included in amphoteric polymer resins. The use of such resins for gluing cardboard from wastepaper ensures its strength in both dry and wet conditions. However, when choosing a resin from a fairly wide range of these reagents on the market, the content of azetidine groups is not included in the list of main characteristics. In this research work, the methods of 1H and 13C NMR spectroscopy were used which allowed carrying out the qualitative and quantitative analysis of the azetidine groups in polyamidamine-epichlorohydrin resins according to their structural and functional characteristics. In order to obtain quantitative information about individual groups of studied polyamidamine-epichlorohydrin resins a new technique was proposed for calculating the relative content of azetidine groups in resins with respect to the theoretically possible content. The essence of the technique was that the 13C NMR spectra of the investigated amphoteric polymer resins were divided into integration intervals corresponding to the nuclei of carbon atoms in the same type of structural fragments of polyamidamine-epichlorohydrin resin molecules. To determine the relative content of azetidine groups, the corresponding values of spectroscopic parameters of carbon atoms (integral line intensities and their ratio) of carboxyl and carbonyl groups, as well as carbon atoms of azetidine groups, were used. In this work, the effect of the researched resins on the main quality indicators of laboratory paper samples of different composition was studied. The research results proved the dependence of paper parameters on the relative content of azetidine groups in the resin.

OBTAINING NANOCELLULOSE FROM BIOMASS AND STUDY OF THEIR PHYSICOCHEMICAL PROPERTIES

This work describes the production of nanocellulose by removing lignin from biomass by the peroxide method in the presence of an H2SO4 catalyst and the study of its physicochemical properties. The structure of cellulose and modified nanocellulose was studied using Raman spectroscopy, IR (infrared) spectroscopy, X-ray diffraction, and SEM (scanning electron microscopy). The resulting increase in the crystallinity of NFC (nanofibrous cellulose) was confirmed by X-ray diffraction analysis. This indicates that cellulose was associated with the removal of amorphous parts. As a result of X-ray diffraction, overlap on NFC radiographs occurred even in the area of intense lines. In the sample obtained by IR spectroscopy, the presence of groups (3413.12 cm−1; 2918.34 cm−1; 1373.30 cm−1; 617.52 cm−1) corresponding to the nature of NFC was detected. Strong absorption at 1429.8 cm−1 in the spectrum of CMC (carboxylmethylcellulose) revealed –COOH groups, indicating successful carboxylation of cellulose. The morphological surface, average particle size and structure of the samples were studied. As a result of a comparative analysis of morphological structures, an ordered filamentous structure of nanofibrous cellulose characteristic of fibers and a porous structure of CMC with a modified surface and uneven fibers were revealed. The developed method for producing modified cellulose from biomass does not require multi-stage processing compared to traditional methods and is safe for the environment. It has been shown that it is possible to obtain high-quality cellulose in one stage without the use of reagents containing sulfur and chlorine, high pressure and high water consumption.

JWST Observations of Young protoStars (JOYS)

Context. Accretion and ejection dictate the outcomes of star and planet formation processes. The mid-infrared (MIR) wavelength range offers key tracers of processes that have been difficult to detect and spatially resolve in protostars until now. Aims. We aim to characterize the interplay between accretion and ejection in the low-mass Class I protobinary system TMC1, comprising two young stellar objects: TMC1-W and TMC1-E at a 85 au separation. Methods. Using the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) observations in 5–28 μm range, we measured the intensities of emission lines of H2, atoms, and ions, for instance, the [Fe II] and [Ne II], and HI recombination lines. We analyzed the spatial distribution of the different species using the MIRI Medium Resolution Spectrometer (MRS) capabilities to spatially resolve emission at 0″​​.2–0″​​.7 scales. we compared these results with the corresponding Atacama Large Millimeter/submillimeter Array (ALMA) maps tracing cold gas and dust. Results. We detected H2 outflow coming from TMC1-E, with no significant H2 emission from TMC1-W. The H2 emission from TMC1-E outflow appears narrow and extends to wider opening angles with decreasing Eup from S(8) to S(1) rotational transitions, indicating the disk wind as its origin. The outflow from TMC1-E protostar shows spatially extended emission lines of [Ne II], [Ne III], [Ar II], and [Ar III], with their line ratios consistent with UV radiation as a source of ionization. With ALMA, we detected an accretion streamer infalling from > 1000 au scales onto the TMC1-E component. The TMC1-W protostar powers a collimated jet, detected with [Fe II] and [Ni II], making it consistent with energetic flow. A much weaker ionized jet is observed from TMC1-E, and both jets appear strikingly parallel to each other, indicating that the disks are co-planar. TMC1-W is associated with strong emission from hydrogen recombination lines, tracing the accretion onto the young star. Conclusions. MIRI-MRS observations provide an unprecedented view of protostellar accretion and ejection processes on 20 au scales. Observations of a binary Class I protostellar system show that the two processes are clearly intertwined, with accretion from the envelope onto the disk influencing a wide-angle wind ejected on disk scales. Finally, the accretion from the protostellar disk onto the protostar is associated with the source launching a collimated high-velocity jet within the innermost regions of the disk.

IL-9 is a Biomarker of BIA-ALCL Detected Rapidly By Lateral Flow Assay.

A delayed seroma around breast implants is the most common clinical presentation of BIA-ALCL. However, most seromas are due to benign causes. Therefore, it is essential to distinguish benign seromas from seromas due to BIA-ALCL. In a prior study mean concentrations of IL-9, IL-10 and IL-13 were found to be significantly higher in BIA-ALCL than in benign seromas. The aim of this research was to test the ability to detect high concentrations of IL-9 rapidly with a lateral flow assay (LFA). Because we previously reported that a LFA for CD30 detected BIA-ALCL in seromas we compared CD30 and IL-9 LFAs in distinguishing BIA-ALCL from benign seromas. Thirty microliter samples of 26 seromas (15 benign, 11 malignant) were tested on in-house prepared strips for IL-9 and CD30. Nanoparticle-conjugated antibodies specific to IL-9 and CD30 were used for detection. IL-9 was analyzed in undiluted samples and CD30 samples were optimized at 1:3 dilution. The dynamic range of detection was determined by spiking recombinant IL-9 into a benign seroma. Image analysis measured intensity of both test line (TL) and control line (CL) and a TL/CL ratio was calculated. IL-9 protein and IL-9 transcription factor PU.1 were stained in BIA-ALCL lines and clinical samples. The IL-9 LFA was reliable in distinguishing BIA-ALCL from benign seromas when the concentration of IL-9 was greater than 10 ng/ml. The CD30 LFA was positive in all 11 malignant cases. In one case with only faint CD30 and IL-10 test lines, the IL-9 LFA was clearly positive. Immunohistochemistry showed IL-9 and its essential transcription factor PU.1 were present in tumor cells in BIA-ALCL lines and clinical samples. IL-9 is a tumor cell biomarker of BIA-ALCL that can be detected by lateral flow assay and immunohistochemistry. Concentrations of IL-9 greater than 10 ng/ml reliably distinguished BIA-ALCL from benign seromas. Moreover, IL-9 LFA could detect BIA-ALCL when CD30 LFA was not definitive and IL-10 was of low concentration with a faint IL-10 TL, suggesting a multiplex LFA including IL-9, CD30 and IL-10 might be more effective in detecting BIA-ALCL in selected cases.

Cavity-enhanced single artificial atoms in silicon

Artificial atoms in solids are leading candidates for quantum networks, scalable quantum computing, and sensing, as they combine long-lived spins with mobile photonic qubits. Recently, silicon has emerged as a promising host material where artificial atoms with long spin coherence times and emission into the telecommunications band can be controllably fabricated. This field leverages the maturity of silicon photonics to embed artificial atoms into the world’s most advanced microelectronics and photonics platform. However, a current bottleneck is the naturally weak emission rate of these atoms, which can be addressed by coupling to an optical cavity. Here, we demonstrate cavity-enhanced single artificial atoms in silicon (G-centers) at telecommunication wavelengths. Our results show enhancement of their zero phonon line intensities along with highly pure single-photon emission, while their lifetime remains statistically unchanged. We suggest the possibility of two different existing types of G-centers, shedding new light on the properties of silicon emitters.

Cross-correlation Techniques to Mitigate the Interloper Contamination for Line Intensity Mapping Experiments

Line intensity mapping (LIM) serves as a potent probe in astrophysics, relying on the statistical analysis of integrated spectral line emissions originating from distant star-forming galaxies. While LIM observations hold the promise of achieving a broad spectrum of scientific objectives, a significant hurdle for future experiments lies in distinguishing the targeted spectral line emitted at a specific redshift from undesired line emissions originating at different redshifts. The presence of these interloping lines poses a challenge to the accuracy of cosmological analyses. In this study, we introduce a novel approach to quantify line–line cross-correlations (LIM-LLX), enabling us to investigate the target signal amid instrumental noise and interloping emissions. For example, at a redshift of z ∼ 3.7, we observed that the measured auto-power spectrum of C ii 158 exhibited substantial bias, from interloping line emission. However, cross-correlating C ii 158 with CO(6–5) lines using an FYST-like experiment yielded a promising result, with a signal-to-noise ratio of ∼10. This measurement is notably unbiased. Additionally, we explore the extensive capabilities of cross-correlation by leveraging various CO transitions to probe the tomographic Universe at lower redshifts through LIM-LLX. We further demonstrate that incorporating low-frequency channels, such as 90 and 150 GHz, into FYST’s EoR-Spec-like experiment can maximize the potential for cross-correlation studies, effectively reducing the bias introduced by instrumental noise and interlopers.

Analysis of an Al-Sn-Cu alloy by calibration-free laser-induced breakdown spectroscopy under varying sample temperature conditions

This study investigates the impact of sample temperature Ts on Laser-Induced Breakdown Spectroscopy (LIBS) emission characteristics and Calibration-Free LIBS (CF-LIBS) quantitative analysis in vacuum and air. Using an aluminum‑tin‑copper alloy, we analyze spectral lines within a 20 °C to 170 °C temperature range. Evaluation encompasses emission line intensities, plasma parameters, expansion imagery, and laser ablation crater morphologies. CF-LIBS analysis underlines that elevated Ts maintains quantitative accuracy even for minor elements with weak lines. In atmospheric conditions, tin segregation occurs, yet CF-LIBS remains robust. These results highlight CF-LIBS's potential for varied applications by mitigating Ts-induced effects.

Photoionization analysis of chemodynamical dwarf galaxies simulations. II. Detailed calculation of diffuse ionizing radiation

ABSTRACT Active star formation in dwarf galaxies shapes the morphology of the surrounding nebular environment and ensures the non-uniformity of the chemical elements spatial distribution in it due to the superwind region expansion. Ionizing radiation within the nebular gas produces observed emission lines used for modelling and diagnostics. We introduce a multicomponent photoionization modelling (MPhM) approach that incorporates detailed calculation of diffuse ionizing radiation (DCDIR) based on chemodynamical simulations (ChDSs). Our models aim to replicate crucial emission line intensity ratios within the observed range, employing a thin dense shell between the superwind region and the outer nebular environment to address ChDSs resolution limitations, which render them insensitive to the presence of a superwind shock. MPhM-generated emission line spectra within a small central synthetic aperture and a thin long-slit exhibit excellent agreement with observations, confirming the accuracy of the ionization structure of the nebular environment obtained using the MPhM + DCDIR approach. However, the outward-only approximation fails to reproduce the dwarf galaxies ionization structure. We determined the oxygen abundance using the $T_e$- and $R_{23}$-methods based on emission lines from MPhM + DCDIR. The resulting abundances align well with values obtained by averaging over the ‘observed’ volume within synthetic apertures, weighted by mass. The escape fraction of ionizing photons from the dwarf galaxy was found to be larger than that obtained using the outward-only approximation. Employing Kennicutt’s calibration corrected for near-UV data, the star formation rate (SFR) was calculated using the ${\rm H}\,\alpha$ luminosity from MPhM + DCDIR. The resulting SFR value is nearly 33 per cent higher than the true one.

Compositional analysis of Silybum marianum plant at reduced pressure using calibration-free LIBS

Silybum marianum is an annual herb with a wide range of therapeutic values due to its high nutritional content. The compositional analysis of different parts of this plant, such as seeds and leaves, was performed using calibration-free laser-induced breakdown spectroscopy. The optical emission spectra from laser-generated plasma of seeds and leaves revealed the elemental profile, including Mg, Na, Ca, K, Si, Al, Zn, Rb, Sr, Fe, Ti, Ba, C, O, H, and N. The study was focused on improving LIBS based quantitative analysis by reducing self-absorption using two approaches.In the first approach, a theoretical model based on the internal reference line method and the relation between experimental and theoretical broadening was established to reduce self-absorption in the measured spectral line at atmospheric pressure. In the second approach, the self-absorption was evaluated at reduced pressure, which shows considerably reduced for most of the spectral lines at 10 mbar pressure. Thereafter, the theoretical model was applied at reduced pressure to further correct the line intensities. Finally, the self-absorption corrected line intensities were used for the compositional analysis of the plant using one-line CF-LIBS. The analytical results obtained with both approaches show that the results of the theoretical model at a reduced pressure are in close agreement with the ICP-MS results.

New line list for the ν4 bands of the trans (790.117 cm–1) and cis (851.943 cm–1) conformers of nitrous acid (HONO): Accurate positions and absolute intensities

The goal of this work was to update and significantly improve the line lists that have been generated recently for 11 µm bands of the trans- and cis- conformer forms of nitrous acid (HONO) [Armante R, Perrin A, Kwabia Tchana F, Manceron L. The ν4 bands at 11 μm: linelists for the trans- and cis- conformer forms of nitrous acid (HONO) in the 2019 version of the GEISA database. Molecular Physics 2021;120:e1951860]. That 2019 version of the 11 µm line list was generated using the spectroscopic parameters that were available, at that time, in the literature. During the present study, we used high-resolution Fourier transform spectra recorded at 11 µm to perform a large investigation of line positions and intensities for the ν4 bands of the trans- and cis-conformer of HONO. The resulting set of experimental ν4 (absolute) intensities and of 41 energy levels were used to determine, by least squares fit computations, improved position and intensity parameters for the ν4 bands of the trans- and cis-conformer of HONO. For trans-HONO, the ν4 band appeared not to be perturbed, while for cis-HONO a weak high order B-type Coriolis, coupling together the 41 and 61 energy levels was evidenced for the first time. This new list is of potential interest for the IASI-NG (Infrared Atmospheric Sounding Interferometer - New Generation) instrument which will be launched on board the METOP-SG satellite in 2025.