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Copyright of Journal of the Institute of Conservation is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

N, Cl-doped carbon dots (N, Cl-CDs) were prepared by hydrothermal method from rhodamine B (RhB) and ethylenediamine (EDA). The resulting N, Cl-CDs exhibited fascinating solvent dependence and strict excitation independence. As the polarity of the solvent increased (from tetrahydrofuran (THF) to water), the emission spectrum of N, Cl-CDs was redshifted and the fluorescence efficiency decreased, which were attributed to hydrogen bond-induced aggregation. Taking advantage of these attributes, the N, Cl-CDs were used as suitable probes for fluorescence and colorimetric dual-mode detection of water in THF. The linear relationship was 0.5–100% water with the detection limit down to 0.093%. Moreover, the sensing platform was converted into a paper-based sensor for handy, real-time, and visible humidity sensing. N, Cl-CDs/PVA films were fabricated and realized continuously tunable solid-state fluorescence, further expanding their practical application. [ABSTRACT FROM AUTHOR]

Efficient and stable blue is the holy grail of OLED. beeOLED pioneers intra‐metallic Europium emitter that offer a unique combination of deep blue single peak emission spectrum, open shell electronic configuration for 100% efficiency, and potential of high operational stability as no organic bonds are weakened during light generation. [ABSTRACT FROM AUTHOR]

Thermally activated delayed fluorescent (TADF) and phosphorescent blue organic light‐emitting diodes (OLEDs) have been developed to overcome the relatively low triplet exciton utilization of traditional fluorescent OLEDs. However, broad emission spectra originating from charge transfer process limits the commercial application of such blue OLEDs. Herein, an effective phosphor‐sensitized fluorescent (PSF) OLED device structure was designed. PSF OLED exhibited a maximum blue index (BI) of 508 cd/A/CIEy with CIEy of 0.060, which has been the highest efficiency result reported for PSF deep‐blue OLEDs. Impressively, the sensitized OLEDs maintained blue index of 407 cd/A/CIEy, narrow emission spectra (FWHM = 17 nm) and high color purity (CIEy = 0.046), revealing the attractive technical advantages and commercial application potential. [ABSTRACT FROM AUTHOR]

Paper-based analytical devices (PADs) are very popular for point-of-care diagnostics, which provide a fast, cost-effective and possible multiplexed detection of a spectrum of molecules. They have been matching forward proudly to contribute to the modern analytical science and life science. Accompanying with their advantages and huge potentials, low detection sensitivity is continuing to challenge the application of PADs from bench to bedside. In order to improve the sensitivity and enhance the signal readout, variable signal amplification strategies have been investigated and applied for PADs. In this review, we have firstly classified formats of PADs according to the engineering design. Advances for improving sensitivity of PADs in recent five years are then summarised according to three popular types of signal amplification strategies (nanomaterial based, nucleic acid based, and engineering of PADs based). Pros and cons of each signal amplification approach have been discussed accordingly. Finally, the future perspectives of PADs are proposed. • Advances on signal amplification strategies to enhance sensitivity of paper based analytical devices (PADs) are outlined. • Three signal amplification strategies (nanomaterial, nucleic acid, and engineering of PADs based) are discussed. • The pros and cons of different signal amplification strategies are compared. • Future perspectives for signal amplification on PADs are proposed. [ABSTRACT FROM AUTHOR]

In the present study, a novel interdigitated coordination polymer (CP) [Zn(cit)(4‐nvp)]n (1) is synthesized using citraconic acid (H2cit) and 4‐(1‐naphthylvinyl)pyridine (4‐nvp) mixed ligands. The efficient dipolar interactions between CP and polar solvents cause the observed redshift in emission spectra and rationalize the positive solvatochromism effect with increased Stokes shift (Δδ) from 5643 to 8547 cm−1 on going from less‐polar to more‐polar solvents. Supramolecular assembly of CP acts as a selective optical sensor toward Pd(II) even in the presence of other relevant contending metal ions in water. Inspired from the solution‐phase sensor activity, the CP is further employed for an on‐site and ecologically green contact mode detection of Pd(II) from water upon readily fabricating cost‐effective and portable thin film via simply drop‐casting aqueous suspension of material (1 mm) on filter paper. Interestingly, the compound exhibits the rare mechanochromic behavior upon external pressure. Hence, the synthesized CP reveals sensing activity in diverse way; in one hand, it demonstrates solvatochromism and, in other hand, it unveils mechanochromism accompanied by the detection of Pd(II) in aqueous medium. [ABSTRACT FROM AUTHOR]

Abstract: X-ray photoelectron spectroscopy (XPS) has been applied to pulp and paper research for decades. However, there has been no attempt to standardise or even systematically compare experimental and analysis procedures, even though it is known that fibrous, nature-derived and insulating fibre materials pose remarkable challenges to reliable surface analysis. The experimental problems are mainly linked with neutralisation, energy resolution, contamination and X-ray induced degradation. We have tested applicability, reliability and reproducibility of XPS analysis on real pulp samples with varying lignin and extractives contents in a small round robin investigation. We also tested the instrumental set-ups with an acetone-extracted filter paper, used as a reference sample. The data, collected at four different laboratories with state-of-the-art instruments indicate that reproducible results can be obtained, despite minor differences in experimental and analysis procedures. However, we found that a specified sample handling procedure and limited X-ray exposure are crucial for reproducible, reliable data. Based on the round robin data we recommend dose restricted monochromatic measurements, a cellulosic in situ reference and a consistent sample handling procedure. The data confirms that a paper-based reference material and the correlation of high-resolution C 1s data with O/C atomic ratios can be used in testing instruments and experimental set-ups for pulp and paper materials. [Copyright &y& Elsevier]

The development of the ultrapure and highly efficient blue organic light‐emitting diodes is a very critical issue in the organic light‐emitting diodes. As an approach, boron‐nitrogen based multi‐resonance compounds have been developed. In this work, a new class of materials were designed and synthesized as the deep blue organic emitters for high efficiency organic light‐emitting diodes. Only carbon and nitrogen were used to design the materials to induce the multi‐resonance effect in the emitters. A deep blue color, a narrow emission spectrum and high efficiency by thermally activated delayed fluorescence were achieved using the new emitting materials. [ABSTRACT FROM AUTHOR]

Hyperfluorescence™ (HF) combines TADF and fluorescence to provide narrow emission spectrum with four times higher emission efficiency than fluorescence. TADF acts as excitons generator and transfers excitons to fluorescence by Förster resonance energy transfer (FRET). HF also achieved long enough lifetime for AMOLED applications, such as smartphone not only by durable molecules but also by controlling charge balances in Emissive Layer (EML). [ABSTRACT FROM AUTHOR]

A theoretical treatment of the vibrational–vibrational (VV) contribution to the vibrational energy relaxation time T1 of a solute normal mode in a molecular solvent, which extends a previous treatment [S. A. Adelman, R. H. Stote, and R. Muralidhar, J. Chem. Phys. 99, 1320 (1993), henceforth called Paper I] of the vibrational–translational–rotational (VTR) contribution to T1, is outlined and expressions for this VV contribution, valid for the infinitely dilute diatomic solution, are presented. The treatment is based on the formula T1=β-1(ωl), where β(ω) is the friction kernel of the relaxing solute mode and where ωl is its liquid phase frequency. β(ω) is evaluated as the cosine transform of the autocorrelation function 〈F(t)Fĩ〉0v of the fluctuating generalized force exerted by the vibrating solvent on the solute normal mode coordinate conditional that this coordinate is fixed at its equilibrium value. 〈F(t)F〉0v is expressed as a superposition of the rigid solvent autocorrelation function 〈F(t)F〉0 and a correction which accounts for solvent vibrational motion. For diatomic solvents one has 〈F(t)F〉0v= 〈F(t)F〉0+NSMD(t) cos ωDt F(ΩD), where NS=number of solvent molecules, MD(t) is the vibrational force gradient autocorrelation function, ωD and ΩD are solvent molecule liquid phase frequencies, and F(Ω)=1/2hΩ-1 coth[hΩ/2kBT].The Gaussian model is assumed for 〈F(t)F〉0 and MD(t) yielding β(ω) as a superposition of a Gaussian centered at ω=0 which mediates VTR processes and a Gaussian centered at ω=ωD which mediates VV processes. Vector integral expressions for MD(t), ωD, and ΩD are presented which are similar to the expressions for ωl and 〈F(t)F〉0 given in Paper I. These expressions permit the evaluation of the VV contribution to T1 from the atomic masses, bondlengths, vibrational frequencies, and site–site interaction... [ABSTRACT FROM AUTHOR]

Comparing a discrete molecular spectrum to a continuous molecular spectrum in a quantitative manner is a challenging problem, for example, when attempting to fit a theoretical stick spectrum to a continuous spectrum. In this paper, the use of computational optimal transport is investigated for such a problem. In the optimal transport literature, the comparison of a discrete and a continuous spectrum is referred to as semi-discrete optimal transport and is a situation where a metric such as least-squares may be difficult to define except under special conditions. The merits of an optimal transport approach for this problem are investigated using the transport distance defined for the semi-discrete case. A tutorial on semi-discrete optimal transport for molecular spectra is included in this paper, and several well-chosen synthetic spectra are investigated to demonstrate the utility of computational optimal transport for the semi-discrete case. Among several types of investigations, we include calculations showing how the frequency resolution of the continuous spectrum affects the transport distance between a discrete and a continuous spectrum. We also use the transport distance to measure the distance between a continuous experimental electronic absorption spectrum of SO2 and a theoretical stick spectrum for the same system. The comparison of the theoretical and experimental SO2 spectra also allows us to suggest a theoretical value for the band origin that is closer to the observed band origin than previous theoretical values. [ABSTRACT FROM AUTHOR]

Hyperfluorescence™ (HF) combines TADF and fluorescence to provide narrow emission spectrum with four times higher emission efficiency than fluorescence. TADF acts as excitons generator and transfers excitons to fluorescence by Förster resonance energy transfer (FRET). HF also achieved long enough lifetime for AMOLED applications not only by durable molecules but also by controlling charge balances in Emissive Layer (EML). As the result of a collaboration with a display panel manufacture, the world's first HF display had been launched. [ABSTRACT FROM AUTHOR]

This paper reports a pioneering attempt at simultaneously analyzing gadolinium (Gd) distribution and surface imaging of surrogate debris samples with homogeneous and heterogeneous composition using a fiber-coupled acoustic wave-assisted microchip laser-induced breakdown spectroscopy (AW-mLIBS) system. This system must be applied to the remote analysis of fuel debris at the Fukushima Daiichi Nuclear Power Station (FDNPS). In the AW-mLIBS system, a microchip LIBS was used to measure the Gd distribution maps in the mixed oxide samples. Whereas, during elemental mapping by microchip LIBS, the laser-plasma acoustic waves were simultaneously recorded by microphone and applied for surface imaging of the samples. Additionally, the laser-plasma acoustic waves can be used to adjust the best-focusing position of the microchip LIBS because the acoustic wave amplitude is the strongest at the near best-focusing position. According to the measurement results, the emission spectra of the surrogate debris showed that the optical emission lines at 501.5 nm and 510.3 nm were suitable for Gd detection in the fuel debris sample. For Gd quantification, calibration curves were established from the intensity ratio of Gd/Ce emission lines, yielding the detection limits for Gd in the range of 0.04–0.09 wt% with a relative standard deviation of 3.9%. The surface imaging for the surrogate debris samples was successfully performed by collecting the laser-plasma acoustic waveforms during LIBS elemental mapping. [ABSTRACT FROM AUTHOR]

We present the MPI-Mainz UV/VIS Spectral Atlas, which is a large collection of absorption cross sections and quantum yields in the ultraviolet and visible (UV/VIS) wavelength region for gaseous molecules and radicals primarily of atmospheric interest. The data files contain results of individual measurements, covering research of almost a whole century. To compare and visualize the data sets, multicoloured graphical representations have been created. The Spectral Atlas is available on the internet at http://www.uv-vis-spectral-atlas-mainz.org. It now appears with improved browse and search options, based on new database software. In addition to the web pages, which are continuously updated, a frozen version of the data is available under the doi:10.5281/zenodo.6951. [ABSTRACT FROM AUTHOR]

Lutosław Wolniewicz, one of prominent quantum chemists, known for his seminal works on the structure and spectra of the hydrogen molecule and its isotopomers, passed away in December 2020. This paper presents his life and works. [ABSTRACT FROM AUTHOR]

The MACE architecture represents the state of the art in the field of machine learning force fields for a variety of in-domain, extrapolation, and low-data regime tasks. In this paper, we further evaluate MACE by fitting models for published benchmark datasets. We show that MACE generally outperforms alternatives for a wide range of systems, from amorphous carbon, universal materials modeling, and general small molecule organic chemistry to large molecules and liquid water. We demonstrate the capabilities of the model on tasks ranging from constrained geometry optimization to molecular dynamics simulations and find excellent performance across all tested domains. We show that MACE is very data efficient and can reproduce experimental molecular vibrational spectra when trained on as few as 50 randomly selected reference configurations. We further demonstrate that the strictly local atom-centered model is sufficient for such tasks even in the case of large molecules and weakly interacting molecular assemblies. [ABSTRACT FROM AUTHOR]

The use of computational optimal transport is investigated as a tool for comparing two molecular spectra. Unlike other techniques for comparing molecular spectra in a pattern-recognition framework, transport distances simultaneously encode information about line positions and intensities. In addition, it is shown that transport distances are a useful alternative to Euclidean distances as Euclidean distances are based on line-by-line comparisons, while transport distances reflect broader features of molecular spectra and adequately compare spectra with different resolutions. This paper includes a tutorial on the use of optimal transport and investigates several well-chosen examples to illustrate the utility of computational optimal transport for comparing molecular spectra. [ABSTRACT FROM AUTHOR]

Multiple monochromatic x-ray imaging (MMI) is a technique for diagnosing the emission spectra of tracer elements in laser-driven inertial confinement fusion experiments. This study proposes an MMI method that combines a simple pinhole array with a laterally graded multilayer mirror. The method directly obtains multiple monochromatic x-ray images by regulating the multilayer thickness in different mirror positions to compensate for the energy-broadening effect. This paper presents a comprehensive design scheme, the multilayer fabrication and experimental verification of the gradient MMI imaging performance. The experimental results show that the method achieves monochromatic imaging with a spectral resolution of ∼70–90 eV in several keV energy regions. This paper presents a practical diagnostic approach for directly and synchronously capturing the spatial, temporal, and spectral information of laser plasma x rays. [ABSTRACT FROM AUTHOR]

This paper proposes a deep learning method to predict the electromagnetic emission spectrum in the electromagnetic compatibility (EMC) test of aerospace products. A threshold‐based data decomposition method is used to propose the spike signal, reconstruct the original test data, and solve the contradiction between the overfitting and prediction accuracy of the deep learning method to deal with the EMC test spectrum. Using a long short‐term memory neural network architecture for predicting electromagnetic emission spectrum, the Bayesian optimization method is used to optimize the network hyperparameter, and the acquisition function is introduced into the loss function to improve the comprehensive training optimization of deep learning network. Apply the method to three numerical examples: signal line current conduction emission, power line voltage conduction emission, and electric field radiation emission. The analysis results indicate that at a 95% confidence level, the predicted electromagnetic emission spectrum is basically consistent with the test results. The prediction results can be used as the basis for EMC evaluation of aerospace electronic equipment. [ABSTRACT FROM AUTHOR]

Southern leaf blight (SLB) is a foliar disease caused by the fungus Cochliobolus heterostrophus infecting maize plants in humid, warm weather conditions. SLB causes production losses to corn producers in different regions of the world such as Latin America, Europe, India, and Africa. In this paper, we demonstrate a non-destructive method to quantify the signs of fungal infection in SLB-infected corn plants using a deep UV (DUV) fluorescence spectrometer, with a 248.6 nm excitation wavelength, to acquire the emission spectra of healthy and SLB-infected corn leaves. Fluorescence emission spectra of healthy and diseased leaves were used to train an Autoencoder (AE) anomaly detection algorithm—an unsupervised machine learning model—to quantify the phenotype associated with SLB-infected leaves. For all samples, the signature of corn leaves consisted of two prominent peaks around 450 nm and 325 nm. However, SLB-infected leaves showed a higher response at 325 nm compared to healthy leaves, which was correlated to the presence of C. heterostrophus based on disease severity ratings from Visual Scores (VS). Specifically, we observed a linear inverse relationship between the AE error and the VS (R2 = 0.94 and RMSE = 0.935). With improved hardware, this method may enable improved quantification of SLB infection versus visual scoring based on e.g., fungal spore concentration per unit area and spatial localization. [ABSTRACT FROM AUTHOR]

Most commercial phosphor-converted white light-emitting diodes (pc-WLEDs) are manufactured with blue LED chips and yellow-emitting Y3Al5O12:Ce3+ (YAG:Ce3+) garnet phosphor, but the lack of blue-green light in the spectrum results in a low color rendering index (CRI). In this paper, we synthesized Y3ScAl4O12:Ce3+ (YSAG:Ce3+) by replacing Al3+ in YAG:Ce3+ with Sc3+. The introduction of Sc3+ with a larger ionic radius through a cation substitution strategy causes lattice expansion, elongation of the Y–O bond, and ultimately a decrease in Ce3+ 5d level crystal field splitting. As a consequence, the emission spectrum undergoes a blue-shift of 10 nm. Furthermore, the YSAG:Ce3+ phosphor exhibits good thermal stability, and its emission intensity at 423 K is about 58% of that at 303 K. Moreover, the analysis of Eu3+ emission spectra demonstrates that the introduction of Sc3+ resulted in a slight reduction of the dodecahedral lattice symmetry. YSAG:Ce3+ effectively compensates for the lack of the blue-green region, and WLEDs with high color rendering index (90.1), low color temperature (4566 K) and high luminous efficiency (133.59 lm W−1) were prepared using the combination of YSAG:0.08Ce3+, CaAlSiN3:Eu2+ and 450 nm blue chips. These findings indicate that YSAG:Ce3+ garnet phosphor has potential to be used in high quality WLEDs. [ABSTRACT FROM AUTHOR]

Parasitoids of concealed hosts have to drill through a substrate with their ovipositor for successful parasitization. Hymenopteran species in this drill-and-sting guild locate immobile pupal hosts by vibrational sounding, i.e., echolocation on solid substrate. Although this host location strategy is assumed to be common among the Orussidae and Ichneumonidae there is no information yet whether it is adapted to characteristics of the host microhabitat. This study examined the effect of substrate density on responsiveness and host location efficiency in two pupal parasitoids, Pimpla turionellae and Xanthopimpla stemmator (Hymenoptera: Ichneumonidae), with different host-niche specialization and corresponding ovipositor morphology. Location and frequency of ovipositor insertions were scored on cylindrical plant stem models of various densities. Substrate density had a significant negative effect on responsiveness, number of ovipositor insertions, and host location precision in both species. The more niche-specific species X. stemmator showed a higher host location precision and insertion activity. We could show that vibrational sounding is obviously adapted to the host microhabitat of the parasitoid species using this host location strategy. We suggest the attenuation of pulses during vibrational sounding as the energetically costly limiting factor for this adaptation. [ABSTRACT FROM AUTHOR]

The shot-to-shot measurement uncertainty restricts the application of laser-induced breakdown spectroscopy (LIBS) technically, to a certain extent. In order to further deepen the understanding of spectral stability, in this paper, the effects of the laser's focus depth, the delay of the spectrometer, and the position of the spectrum collection on the spectral stability were carefully researched. Moreover, the dynamic characteristics of plasma were studied at different laser focusing depths. Research has found that the morphological changes of plasma are relatively stable, without significant changes, despite varying depths of laser focus on the sample surface. In addition, it was found that stable elemental emission spectra can always be obtained in the early plasma aggregation region. [ABSTRACT FROM AUTHOR]

Fluorescence pH sensing has proven to be efficient but with the drawback that molecules photobleach, requiring frequent calibrations. Double-emission peak molecules allow ratiometric measurements and theoretically avoid calibration. However, they are often expensive and fragile and usually have very low quantum yields. Single emission peaks such as fluorescein and derivatives are inexpensive and have very high quantum yields. Because they are single emission peaks, the pH is assumed to be derived from the ratio of emitted intensities at measured pH and at high pH values, i.e., they require frequent calibration. However, the shape of their single emitted peak evolves slightly with pH. In this paper, we first demonstrate a simple method to calculate the emission spectrum shape of each prototropic form of fluorescein (and derivatives) as well as the values of the pKas. A complete model of the evolution of the emission spectrum shape with pH is then constructed. Second, we evaluate the potential of these molecules for pH sensing by fitting the experimental spectra with the complete emission model. The method is applied to fluorescein, FITC and FAM. Depending on the molecule, pH can be measured from pH 1.9 to pH 7.3 with standard deviations between 0.06 and 0.08 pH units. Estimating pH and pKas from shape instead of intensity allows calibration-free measurements even with single-emission peak molecules. [ABSTRACT FROM AUTHOR]

A key challenge in quantum photonics today is the efficient and on-demand generation of high-quality single photons and entangled photon pairs. In this regard, one of the most promising types of emitters are semiconductor quantum dots, fluorescent nanostructures also described as artificial atoms. The main technological challenge in upscaling to an industrial level is the typically random spatial and spectral distribution in their growth. Furthermore, depending on the intended application, different requirements are imposed on a quantum dot, which are reflected in its spectral properties. Given that an in-depth suitability analysis is lengthy and costly, it is common practice to pre-select promising candidate quantum dots using their emission spectrum. Currently, this is done by hand. Therefore, to automate and expedite this process, in this paper, we propose a data-driven machine-learning-based method of evaluating the applicability of a semiconductor quantum dot as single photon source. For this, first, a minimally redundant, but maximally relevant feature representation for quantum dot emission spectra is derived by combining conventional spectral analysis with an autoencoding convolutional neural network. The obtained feature vector is subsequently used as input to a neural network regression model, which is specifically designed to not only return a rating score, gauging the technical suitability of a quantum dot, but also a measure of confidence for its evaluation. For training and testing, a large dataset of self-assembled InAs/GaAs semiconductor quantum dot emission spectra is used, partially labelled by a team of experts in the field. Overall, highly convincing results are achieved, as quantum dots are reliably evaluated correctly. Note, that the presented methodology can account for different spectral requirements and is applicable regardless of the underlying photonic structure, fabrication method and material composition. We therefore consider it the first step towards a fully integrated evaluation framework for quantum dots, proving the use of machine learning beneficial in the advancement of future quantum technologies. [ABSTRACT FROM AUTHOR]

Molecular properties prediction is an important task in the field of materials, especially in computational drug and materials discovery. Deep learning (DL) is one of the most popular methods for molecular properties prediction due to its ability to establish quantitative relationships between molecular representations and target properties. In order to improve the performance of DL algorithms, it is crucial to select appropriate representation of molecules. Molecular graph has become one of the choices as it can be easily input into graph neural network (GNN)-based DL models for learning. However, model performance is limited if molecular representation is only used because it only contains atomic information, bond information, and adjacency relationships between atoms. Therefore, we use molecular mass spectrum as another representation to provide supplement information which is not contained in the graph data. In this paper, a transformer-based model, named Mass Spectrum Transformer (MST), is proposed to perform quantitative analysis of molecular spectra, then it is combined with the graph neural network to form a multi-modal data fusion model TransG-Net for accurate molecular properties prediction. Several feature fusion methods are adopted and the best method is chosen to further enhance the performance of the model. A multi-modal dataset is collected in this paper which is composed of molecular graph data and spectra. Data augmentation is performed to simulate the experimentally measured molecular spectra for the generalizability of the model. Experimental results show that MST outperforms previous best mass spectrum-based methods for molecular properties prediction. In addition, TransG-Net combining MST and GNN achieves better performance than state-of-the-art well-designed message passing models, which proves the effectiveness of our multi-modal data fusion method. [ABSTRACT FROM AUTHOR]

In addition to the exciting fundamental questions of quantum computing and implementation possibilities of quantum computers, it is important to look for application areas of quantum computing, to point out practical cases which justify the need for this technology. Besides the well-known qubit-based quantum computers, there are also devices based on other foundations that can surpass the capabilities of classical computers. Among these, devices operating on the basis of boson sampling have a naturally occurring application: the approximate calculation of the vibrational spectrum of molecules. Two separate research groups, Huh et al. [14] and Wang et al. [22] created quantum simulators based on boson sampling, which were successfully used to calculate the transition probabilities between specific states of small molecules. Following the methodology found in these two articles, this paper presents how the calculations of transition probabilities can be performed on a classical computer using a quantum computer simulator which is based on Gaussian boson sampling. [ABSTRACT FROM AUTHOR]

The search for biominerals is one of the core targets in the deep space exploration mission. Stromatolite phosphorite is a typical biomineral that preserves early life on Earth. The enrichment of phosphate is closely related to microorganisms and their secretions. Laser-induced breakdown spectroscopy (LIBS) has become an essential payload in deep space exploration with the ability to analyze chemical elements remotely, rapidly, and in situ. This paper aims to evaluate the rapid identification of biological and non-biological minerals through a remote LIBS payload. LIBS is used for element analysis and mineral classification determination, and molecular laser-induced fluorescence (MLIF) is used to detect halogenated element F to support the existence of fluorapatite. This paper analyzes the LIBS-MLIF spectral characteristics of stromatolites and preliminarily evaluates the feasibility of P element quantification. The results show that LIBS technology can recognize biological and non-biological signals. This discovery is significant because it is not limited to detecting and analyzing element composition. It can also realize the detection of molecular spectrum based on selective extraction of CaF molecule. Therefore, the LIBS payload still has the potential to search for biomineral under the condition of adjusting the detection strategy. [ABSTRACT FROM AUTHOR]

In this paper, a novel methodology is presented for the construction of ab initio effective rotation–vibration spectroscopic models from potential energy and dipole moment surfaces. Non-empirical effective Hamiltonians are obtained via the block-diagonalization of selected variationally computed eigenvector matrices. For the first time, the derivation of an effective dipole moment is carried out in a systematic way. This general approach can be implemented quite easily in most of the variational computer codes and turns out to be a clear alternative to the rather involved Van Vleck perturbation method. Symmetry is exploited at all stages to translate first-principles calculations into a set of spectroscopic parameters to be further refined on experiment. We demonstrate on H2CO, PH3, CH4, C2H4, and SF6 that the proposed effective model can provide crucial information to spectroscopists within a very short time compared to empirical spectroscopic models. This approach brings a new insight into high-resolution spectrum analysis of polyatomic molecules and will be also of great help in the modeling of hot atmospheres where completeness is important. [ABSTRACT FROM AUTHOR]

A generalized framework of spectrum sensing disruption for a power-limited adversary is proposed in this paper. In the literature, a conventional sensing attack typically assumes that the adversary has perfect knowledge of the spectral usage status. The framework in this paper considers a more general case where there are uncertainties in the estimates at the adversary. These uncertainties are modeled utilizing the probability of detection and the probability of false alarm. Then, the sum of the conditional probabilities of false detection at the secondary within the spectral range of interest, conditioned on the adversary’s estimated spectrum usage status, is maximized. It is shown that the optimal sensing attack, given perfect estimation is a special case of the proposed framework. When the adversary has perfect spectrum usage information, this framework reduces to a previously demonstrated optimal sensing disruption. When the adversary has imperfect information on the spectral status, the proposed framework is significantly more robust than conventional sensing attacks. Further, when the adversary’s power budget increases, it asymptotically approaches the sensing disruption performance upper bound. [ABSTRACT FROM AUTHOR]

The study of the carbon cycle is profound to the global ecosystem. In this paper, isotopic spectroscopy based on laser-induced breakdown spectroscopy (LIBS) was applied to the online detection of carbon isotopes and the study of atmospheric carbon cycle. The emission of carbon dioxide in the atmosphere was simulated by using a laser beam to ablate the coal, wood and paper samples. The emission spectra of smoke showed that carbon dioxide in the smoke could be detected online by the analysis of the molecular spectrum of the CN radicals. Then, taking urea as a carbon isotope sample, the isotopic shifts in the CN molecular spectra were clearly observed. The emission band of the (1,0) transition occurs red-shift of about 0.6 nm, while the emission band of the (0,1) transition appears blue-shift of about 0.8 nm. Furthermore, gaseous 13CO2 was directly detected by LIBS and the isotopic shifts in the CN bands from CO2 were also measured. Moreover, the energy differences in the isotopic shifts of the CN emission bands were calculated based on the density functional theory with the B3PW91/6-31+G(d) basis set, and the calculation results were basically consistent with the experimental values. Finally, the wavelength shifts for all the six different combinations of carbon and nitrogen isotopes were calculated. All the results indicate that the LIBS technique combined with an isotope spectrum is a promising and effective online detection method of gaseous carbon isotopes. [ABSTRACT FROM AUTHOR]

The results of an extensive ab initio study of the cyanobutadiyne cation, initially motivated by threshold-photoelectron spectroscopy experiments [see the study by Gans et al., J. Chem. Phys. 150, 244304 (2019)], are reported in the present paper. Calculations at the internally contracted multireference configuration interaction level of theory have been performed to derive the rovibronic properties of the seven lowest electronic states of HC5N+. Equilibrium geometries, rotational constants, vibrational frequencies, electric dipole moments, and spin-orbit constants have been calculated and compared with experimental data when available. Adiabatic and vertical ionization energies from the neutral ground state as well as transition energies within the cation electronic manifold are predicted, using the convergence to the complete basis set limit. The accurate description of the complex energy landscape up to 32 000 cm−1 above the ionization potential allows us to perform Franck-Condon simulations of the photoionization spectrum to the X+2Π, A+2Π, B+2Σ+, and C+2Π states and allows us to simulate the A+2Π → X+2Π emission spectrum. The vibronic perturbations occurring on the excited potential energy surfaces are revealed and discussed, in particular, for the 3 2Π surface, which presents a double-well topography. [ABSTRACT FROM AUTHOR]

For coherent Raman spectroscopies, common femtosecond pulses often lie in an intermediate regime: their bandwidth is too wide for measurements in the frequency domain, but their temporal width is too broad for homodyne measurements in the time domain. A recent paper [S. Nath et al., Phys. Rev. Lett. 97, 267401 (2006)] showed that complete Raman spectra can be recovered from intermediate length pulses by using simultaneous time and frequency detection (TFD). Heterodyne detection and a phase-stable local oscillator at the anti-Stokes frequency are not needed with TFD. This paper examines the theory of TFD Raman in more detail; a companion paper tests the results on experimental data. Model calculations illustrate how information on the Raman spectrum is transferred from the frequency domain to the time domain as the pulse width shortens. When data are collected in both dimensions, the Raman spectrum is completely determined to high resolution, regardless of the probe pulse width. The loss of resolution in many femtosecond coherent Raman experiments is due to the restriction to one-dimensional data collection, rather than due to a fundamental restriction based on the pulse width. [ABSTRACT FROM AUTHOR]

The preceding paper showed that, in principle, a high-resolution coherent Raman spectrum can be recovered using femtosecond probe pulses by combined detection in both time and frequency. This measurement is possible even when the pulses are too broad in frequency for conventional frequency-domain spectroscopy and too broad in time for conventional time-domain spectroscopy. In this paper, the method is tested on experimental coherent anti-stokes Raman spectroscopy data from acetonitrile. Compared to theoretical models, experimental data are complicated by noise and incomplete knowledge of the pulse structure. Despite these complications, most of the information in the Raman spectrum is recovered from the data: weak transitions are detected and natural-linewidth resolution is achieved across an 800 cm-1 spectral range. However, circumstances in which experimental limitations result in missed features or ambiguities in the recovered spectrum are also identified. These results suggest where improvements in measurement and data analysis can be made. [ABSTRACT FROM AUTHOR]

Background: Trees have developed a broad spectrum of molecular mechanisms to counteract oxidative stress. Secondary metabolites via phenolic compounds emblematized the hidden bridge among plant kingdom, human health, and oxidative stress. Although studies have demonstrated that abiotic stresses can increase the production of medicinal compounds in plants, research comparing the efficiency of these stresses still needs to be explored. Thus, the present research paper provided an exhaustive comparative metabolomic study in Dalbergia odorifera under salinity (ST) and waterlogging (WL). Results: High ST reduced D. odorifera's fresh biomass compared to WL. While WL only slightly affected leaf and vein size, ST had a significant negative impact. ST also caused more significant damage to water status and leaflet anatomy than WL. As a result, WL-treated seedlings exhibited better photosynthesis and an up-regulation of nonenzymatic pathways involved in scavenging reactive oxygen species. The metabolomic and physiological responses of D. odorifera under WL and salinity ST stress revealed an accumulation of secondary metabolites by the less aggressive stress (WL) to counterbalance the oxidative stress. Under WL, more metabolites were more regulated compared to ST. ST significantly altered the metabolite profile in D. odorifera leaflets, indicating its sensitivity to salinity. WL synthesized more metabolites involved in phenylpropanoid, flavone, flavonol, flavonoid, and isoflavonoid pathways than ST. Moreover, the down-regulation of L-phenylalanine correlated with increased p-coumarate, caffeate, and ferulate associated with better cell homeostasis and leaf anatomical indexes under WL. Conclusions: From a pharmacological and medicinal perspective, WL improved larger phenolics with therapeutic values compared to ST. Therefore, the data showed evidence of the crucial role of medical tree species' adaptability on ROS detoxification under environmental stresses that led to a significant accumulation of secondary metabolites with therapeutic value. [ABSTRACT FROM AUTHOR]

This study describes the rational development and synthesis of a benzothiazole-salicylaldehyde Schiff base probe 1. This probe is designed to function as a ratiometric fluorescent probe specifically for detecting ClO− ions, utilizing the imine bond as the fluorophore unit. Upon interaction with ClO− ions, probe 1 exhibits a redshift in its absorption spectrum from 435 nm to 450 nm. Moreover, in its emission spectrum, there is a ratiometric emission enhancement observed at 610 nm, providing a clear indication of the presence of ClO− ions. The sensitivity of probe 1 for detecting ClO− ions is quantified, revealing a lowest detection limit of 5.5 μM, indicating its potential for sensitive detection even at low concentrations of ClO− ions. Additionally, it has been successfully utilized for biological imaging purposes, demonstrating low cytotoxicity, which is crucial for its applicability in biological systems. [ABSTRACT FROM AUTHOR]

A ground-based 110 GHz radiometer was designed to measure the stratospheric ozone vertical profile by observing the 110.836 GHz ozone emission spectrum and the instrument has been operational at Sookmyung Women's University (37.54° N, 126.97° E) in Seoul, Korea. In this paper, we detail the instrumental design, calibration procedures, correction methods, and the retrieved ozone vertical profile. The instrument is a heterodyne total power radiometer. It down-converts the observed 110.836 GHz ozone frequency to 0.609 GHz, with a frequency resolution of 61 kHz and a bandwidth of 800 MHz. The spectral intensity is digitized using a fast Fourier transform spectrometer. For hot-cold calibration, we use microwave absorbers at room temperature and liquid nitrogen as calibration targets. Tropospheric opacity is corrected using the continuous tipping curve calibration. The measured opacities were compared with simulated values from the Korea Local Analysis and Prediction System (KLAPS) data. Additionally, since 2016, the stratospheric ozone profiles over Seoul have been demonstrated for the vertical range of 100 hPa – 0.3 hPa (16 km–70 km) with validation performed by comparing them to the ozone profiles from the MLS on AURA satellite. [ABSTRACT FROM AUTHOR]

Two-dimensional electronic–vibrational spectroscopy (2DEVS) is an emerging spectroscopic technique which exploits two different frequency ranges for the excitation (visible) and detection (infrared) axes of a 2D spectrum. In contrast to degenerate 2D techniques, such as 2D electronic or 2D infrared spectroscopy, the spectral features of a 2DEV spectrum report cross correlations between fluctuating electronic and vibrational energy gaps rather than autocorrelations as in the degenerate spectroscopies. The center line slope of the spectral features reports on this cross correlation function directly and can reveal specific electronic–vibrational couplings and rapid changes in the electronic structure, for example. The involvement of the two types of transition moments, visible and infrared, makes 2DEVS very sensitive to electronic and vibronic mixing. 2DEV spectra also feature improved spectral resolution, making the method valuable for unraveling the highly congested spectra of molecular complexes. The unique features of 2DEVS are illustrated in this paper with specific examples and their origin described at an intuitive level with references to formal derivations provided. Although early in its development and far from fully explored, 2DEVS has already proven to be a valuable addition to the tool box of ultrafast nonlinear optical spectroscopy and is of promising potential in future efforts to explore the intricate connection between electronic and vibrational nuclear degrees of freedom in energy and charge transport applications. [ABSTRACT FROM AUTHOR]

In this paper, an array wire-to-wire surface dielectric barrier discharge (DBD) structure is used to generate large-scale plasma by bipolar nanosecond pulse power in atmospheric air. The quantity of electrodes can be adjusted from 1 to 10 for varying discharge area. The applied voltage and discharge current are measured, the discharge images are captured, and optical emission spectra (OES) are collected. The discharge power, discharge area, and OES intensity for a single group of/and whole structure are calculated. The vibrational and rotational temperatures are simulated by the OES of N2 (C-B, $\Delta \nu =-2$), and the effects of the quantity of electrodes on discharge current, discharge power, discharge area, OES intensity, and vibrational and rotational temperatures are investigated. The results show that the discharge current has two main peaks during single applied pulse voltage, and decays in a fluctuant type. As the quantity of electrodes increases, the peak value of discharge current increases and the decaying time from peak value to zero around becomes longer. The discharge power, discharge area, and OES intensity have increasing tendencies, and those of the single group of wires decrease. In addition, when the quantity of electrodes increases, the vibrational temperature increases first and then decreases, and the rotational temperature varies in a fluctuant type. [ABSTRACT FROM AUTHOR]

Multi‐resonance based boron emitters have attracted great attention as blue emitters for organic light‐emitting diodes because of narrow emission spectrum and high external quantum efficiency as deep blue emitters. Their unique emission properties make them promising as next generation blue emitters. In this work, we report various application of the boron emitters in the white organic light‐emitting diodes and exciplexes for high external quantum efficiency. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have attracted a lot of attention over the past decades due to their sharp emission spectrum and color, which can be tuned by changing just the particle size and chromophoric stability. All these advantages of QDs make quantum dot light-emitting diodes (QLEDs) promising candidates for display and light-source applications. This paper demonstrates a large-emitting-area QLED fabricated by a full-solution process. This QLED is composed of indium tin oxide (ITO) as the anode, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT: PSS) as the hole injection layer (HIL), and poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine (poly-TPD) as the hole-transport layer (HTL). The light-emitting layer (EML) is composed of green CdSe/ZnS quantum dots. By applying the ZnO nanoparticles as the electron-injection/transport layer, QLED devices are prepared under a full-solution process. The large-emitting-area QLED exhibits a low turn-on voltage of around 2~3 V, and the International Commission on Illumination (CIE) 1931 coordinate value of the emission spectrum was (0.31, 0.66). The large emitting area and the unique QLED structure of the device make it possible to apply these features to inkjet printing quantum dot light sources and quantum dot display applications. [ABSTRACT FROM AUTHOR]

This paper reports the use of Raman and time-domain terahertz spectroscopy to ascertain the potential of antibiotic cefixime drug which is widely used for curing bacterial infections and obtained from different pharmaceuticals companies. The indigenously designed terahertz spectrometer between 0.1–2.8 THz range was employed for recording of time domain spectra of drug molecules. The refractive index, absorption coefficients and absorbance strength of this drug in THz domain were also ascertained. THz-Raman spectra simultaneously helps to characterize the crystalline nature of cefixime.s and its chemical composition and effect and concentration of its principal ingredients. The Raman spectra of these drugs molecules was recorded for cross verification of previous experimental findings. Finally, we have identified the absorbance strength of two important ingredients, i. e., sulpha pyridine and sulpha thiazoles and specific absorbance of these ingredients was ascertained in THz domain to quantify the concentration per milligram level between 0.5 and 0.8 THz range. The obtained results reveal that concentration of these two ingredients varies from sample to sample. It help to determine the efficacy and side effects of the drugs produced from different manufacturers. [ABSTRACT FROM AUTHOR]

The optical spectra of ultraluminous X-ray sources (ULXs) show signs of powerful outflows of matter. These outflows are responsible for the formation of a significant portion of optical and ultraviolet emission in ULXs and can either be stellar winds of the donor stars or optically thick outflows (winds) from the surface of supercritical accretion disks. In the latter scenario the outflows are still expected to be similar to stellar winds of massive stars, which allows one to use the same methods for their study based on a comparison of the observed spectra with those simulated within the framework of non-LTE extended atmosphere models. In this paper, we simulate the optical spectrum of the ultraluminous X-ray pulsar NGC 7793 P13, assuming that its emission part is produced in the wind of the supercritical accretion disk. The estimated mass loss rate is about yr . We consider the positive and negative aspects of the model and also discuss the applicability of the concept of supercritical disk winds to NGC 7793 P13 and to another well-known ultraluminous X-ray pulsar, NGC 300 ULX-1. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach to optimize the performance and emission characteristics of a single cylinder compression ignition engine using diesel-hydrogen dual fuel. A TMI (timed manifold injection) system was designed employing an ECU (electronic control unit) for hydrogen induction into the engine manifold. The results showed a significant enhancement in BTHE (12.44% Max. enhancement at 85% full load condition under DH4 strategy) compared to base-diesel operation. The NOx emissions were enhanced to a maximum of 10.33 g/kw-hr at full load under the DH4 strategy. The emissions of UHC were found to be higher at lower loads and get significantly reduced to a maximum of 3.98 g/kw-hr at full load under the DH2 strategy. In comparison, soot emissions decrease substantially and are reduced to a maximum of 0.02 g/kw-hr at 85% full load condition under the DH5 strategy. The proposed method utilizes a Spherical Fuzzy MARCOS MCGDM-based Type-3 Fuzzy Logic approach, which integrates several criteria and uncertain inputs to improve decision-making. The paper outlines the theoretical framework of the approach and the experimental setup used for validation. The results demonstrate that the proposed method significantly reduces emissions while simultaneously improving the engine's performance. Overall, this study offers an innovative and effective solution for optimizing the performance and emissions of diesel-hydrogen dual fuel engines. • Pure diesel and diesel–H 2 blends are expermented. • Diesel–H 2 blends enhanced BTHE than pure diesel in all part loads. • Diesel–H 2 blends reduced the overall emission spectrum for the existing engine. • The performance-emission trade-off prediction studied using Type-3 Fuzzy Logic. • Spherical Fuzzy MARCOS was used to select the most effective predictive logic scheme. [ABSTRACT FROM AUTHOR]