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Interference is widely regarded as a foundational attribute of quantum mechanics. However, for a given experimental arrangement, interference can either contribute or not contribute to the outcome depending upon the basis in which it is measured. This observation is both foundational and particularly relevant to coherent control of molecular processes, an approach based upon quantum interference. Here, we address this issue and its relevance to controlling molecular processes via the "coherent control scattering (CCS) matrix," a formalism that allows for an analysis of modifications in an interference structure resulting from a change of basis. This analysis reveals that the change in the interference structure can be attributed to the non-commutativity of the transformation matrix with the CCS matrix and the non-orthogonality of the transformation. Additionally, minimal interference is shown to be associated with the CCS eigenbasis and that the Fourier transform of the eigenvectors of the CCS matrix provides the maximal interference and hence the best coherent control. The change of controllability through a change of basis is illustrated with an example of 85Rb+ 85Rb scattering. In addition, the developed formalism is applied to explain recent experimental results on He + D2 inelastic scattering demonstrating the presence or absence of interference depending on the basis. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate that the weak temperature dependence of the structure factor of supercooled liquids, a defining feature of the glass transition, is a consequence of the averaging of the scattering intensity due to angular averaging. We show that the speckle at individual wavevectors, calculated from a simulated glass former, exhibits a Debye–Waller factor with a sufficiently large temperature dependence to represent a structural order parameter capable of distinguishing liquid from glass. We also extract from the speckle intensities a quantity proportional to the variance of the local restraint, i.e., a direct experimental measure of the amplitude of structural heterogeneity. [ABSTRACT FROM AUTHOR]

Cerumen, commonly known as earwax, is a complex mixture composed of secretions from ceruminous glands. These secretions are heterogeneous mixtures mainly composed of lipids and proteins. Despite its prevalence, the potential diagnostic value of cerumen remains largely unexplored. Here, we present an in-depth analysis of cerumen utilizing well-known vibrational approaches such as conventional Raman spectroscopy or surface-enhanced Raman spectroscopy (SERS) together with advanced vibrational spectroscopy techniques such as coherent Raman scattering (CRS), i.e. broadband coherent anti-Stokes Raman scattering (CARS) or stimulated Raman scattering (SRS), as well as optical photothermal infrared (OPTIR) spectroscopy. Through the integration of these vibrational spectroscopic methods, lipids and proteins can be identified as the main components of cerumen; however, they contribute to the final spectral information to various extents depending on the vibrational detection scheme applied. The inherently weak Raman signal could be enhanced by linear (SERS) and non-linear (CRS) processes, resulting in efficient acquisition of fingerprint information and allowing for the detection of marker modes, which cannot be addressed by conventional Raman spectroscopy. OPTIR spectroscopy provides complementary information to Raman spectroscopy, however, without the contribution of a fluorescence background. Our findings underscore the utility of these cutting-edge techniques in unveiling the intricate molecular landscape of cerumen, paving the way for novel point-of-care diagnostic methodologies and therapeutic interventions. [ABSTRACT FROM AUTHOR]

The article presents a comprehensive investigation of the crystal structure, impedance spectra, magnetic, magnetodielectric, and magnetoresistive properties of (1- x)CoFe 2 O 4 – x PbTiO 3 composites with varying concentrations (х = 0, 0.2, 0.4, and 0.6). The study also examines the effects of applying a uniaxial pressure of 1 GPa to the synthesized powders using Bridgman anvils. Our findings reveal that the synthesis of these composites results in the formation of an additional phase, lead hexaferrite PbFe 12 O 19 , which exhibits multiferroic properties. Additionally, the coherent scattering region of the components is significantly reduced after mechanical activation. Notably, the real part of the resistivity ρ ′(ω) of nanostructured CoFe 2 O 4 ceramics increases eightfold at T = 240 °C. The composites demonstrate significant magnetoresistance at room temperature, reaching up to 250 %. The study also reveals that the signs of the magnetodielectric MD (B) and magnetoresistive coefficient MR (B) vary with the frequency of the measuring field for certain concentrations. Using the first-order reversal curve (FORC) method, it was observed that after nanostructuring CoFe 2 O 4 through mechanical activation, the interaction field H u shifts from ± 0.6 kOe to ± 0.8 kOe, while the coercive field H c increases from 1.05 kOe to 5 kOe. Moreover, the two-dimensional FORC maps of the composites show increased complexity, due to the formation of additional magnetic phases. [ABSTRACT FROM AUTHOR]

We present super-resolved coherent anti-Stokes Raman scattering (CARS) microscopy by implementing phase-resolved image scanning microscopy, achieving up to two-fold resolution increase as compared with a conventional CARS microscope. Phase-sensitivity is required for the standard pixel-reassignment procedure since the scattered field is coherent, thus the point-spread function is well-defined only for the field amplitude. We resolve the complex field by a simple add-on to the CARS setup enabling inline interferometry. Phase-sensitivity offers additional contrast which informs the spatial distribution of both resonant and nonresonant scatterers. As compared with alternative super-resolution schemes in coherent nonlinear microscopy, the proposed method is simple, requires only low-intensity excitation, and is compatible with any conventional forward-detected CARS imaging setup. The authors present super-resolved CARS microscopy using phase-sensitive image scanning, achieving nearly twice the resolution of conventional CARS. This method requires low excitation laser power and integrates easily into existing systems. [ABSTRACT FROM AUTHOR]

To date, supercontinuum light in the visible and near‐infrared ranges is readily realizable by the optical Kerr effect through self‐phase modulation of ultrashort laser pulses in transparent media. However, it is still a challenge to extend the supercontinuum spectrum down to the deep‐ultraviolet (DUV) range, which is particularly needed for exploring ultrafast dynamics in chemistry, materials, and biology. Here, an approach of non‐resonant coherent Raman scattering is developed to generate ultra‐broadband visible‐DUV supercontinuum in ambient air with a spectral range spanning over 250 nm and a wavelength down to 220 nm. A rovibrational coherence is established in air molecules by filamentation of a near‐infrared femtosecond 800 nm pulse and two femtosecond Raman laser pulses at 267 and 400 nm are introduced into the coherent media to induce non‐resonant coherent Stokes and anti‐Stokes Raman scatterings, which serve as the spectral bridges to link the neighboring Raman pump laser spectra, resulting in ultra‐broadband supercontinuum light. The mechanism is further verified by examining the broadening of picosecond N2+ laser lines with narrow bandwidths (10–30 cm−1), which forms a supercontinuum spectrum spanning over 150 nm. The work provides a viable route for the establishment of coherent DUV supercontinuum in the gas media at designed wavelength ranges. [ABSTRACT FROM AUTHOR]

We have been developing nanosized graphene, called graphene flower, as a material that induces coherent scattering very cold neutrons. Previous experiments have found that the seed part of the graphene flower is more effective than the petal part in increasing the coherent scattering. Based on these results, we found that further modification of the graphene flower to increase the seed portion increased the total cross-section, although it did not reach the level of nanodiamonds. [ABSTRACT FROM AUTHOR]

1.4418 hardened stainless steel (SS) is widely used in mechanical engineering because of its high functional properties. They can also be enhanced by procuring improvements in the state of the surface layer (SL) and, above all, in the factors of its strengthening, among others the average size of coherent scattering regions (ASCSR), dislocation density (DD), residual stresses (RS) of first and second orders, and relative micro-deformations of the crystal lattice (RMCL). This study investigates the effect of cutting speed (vc) ranging from 100 to 250 m/min and feed rate (f) ranging from 0.005 to 0.25 mm/rev on the indicators of SL condition after finish turning the steel tested. A reduction in ASCSR values below 8 nm was obtained for vc = 100–135 m/min, while an increase of ~ 20% was obtained for 180–250 m/min and with the f ranging from 0.2 to 0.25 mm/rev. An increase in RMCL of ~ 90% was registered for vc = 170–230 m/min and f = 0.2–0.25 mm/rev. A decrease in DD below 109 cm−2 was obtained for vc = 180–250 m/min and its ~ 25% increase for vc = 100–135 m/min. A high correlation between ASCSR and DD was shown. In the deformed material, the dislocation's resistance to motion increases in proportion to the increase in its density. A high linear correlation coefficient in the range of 0.8–0.9 is found between ASCSR, DD, and first-order RS on the one hand, and Sa and Sz surface texture parameters, which are used in the industry to assess product quality, on the other. Additionally, the effect of plastic side flow (PSF) was observed and described. When machining with vc = 119 m/min and f = 0.22 mm/rev, the intense plastic deformation of the material causes outflow and shearing of the surface micro-hills. Favorable compressive stresses (below − 100 MPa) were registered in the range of vc = 225–250 m/min at f = 0.005–0.05 m/rev and 0.2–0.25 mm/rev, as well as vc = 115–180 m/min and f = 0.05–0.17 mm/rev. The study proved the existence of a relationship between the cutting parameters and indicators of the thin crystalline structure of SL. This means that by proper controlling of these parameters, it is possible to obtain such a state of the SL workpiece, which will ensure its long-term use. [ABSTRACT FROM AUTHOR]

Led by the National Space Science Center of the Chinese Academy of Sciences, we have built a Chinese dual auroral radar network in northern China, which is called the CN‐DARN. The CN‐DARN consists of three pairs of high‐frequency coherent scattering radar facilities and is one of the key parts of the Chinese Meridian Project Phase II. It has been fully constructed and started trial operations at the end of 2023. The detection range of the radar network extends longitudinally over approximately 9 hr of local times and covers the middle to high latitudes of the entire Asia region above 40° ${}^{\circ}$. In this paper, we present the basic design of the CN‐DARN and its preliminary observations of ionospheric irregularities, subauroral polarization streams (SAPSs) and traveling ionospheric disturbances (TIDs). We also investigate its contribution to the ionospheric convection pattern of the Northern Hemisphere derived from Super Dual Auroral Radar Network (SuperDARN) observations. The results indicate that the CN‐DARN provides excellent measurements and better specifications of flows in the Asian sector, improving our understanding of the global‐scale ionospheric convection pattern in the Northern Hemisphere. These encouraging results lead us to believe that the CN‐DARN will play an important role in studies on the evolution of ionospheric irregularities, the characteristics and evolution of SAPSs, the propagation of TIDs, and global‐scale ionospheric convection dynamics. Plain Language Summary: The ionosphere is home to all charged particles in the Earths atmosphere, and it is also home to many satellites, including space stations. The density of the charged particles is uneven. There are different scales of electron density irregularities in the ionosphere and they can disrupt signals. To monitor the ionospheric environment of the mid‐ and high‐ latitude regions of Asia, three pairs of high‐frequency coherent scattering radars have been deployed in northern China. This network of radars is called the CN‐DARN, short for the Chinese Dual Auroral Radar Network. The CN‐DARN achieves large‐scale continuous detection of the movement of decameter‐scale ionospheric irregularities in the middle and high latitudes of the Asian sector. The detection range can reach 4,000 km from south to north and extends longitudinally over 9 hr of local time. We describe the basic design and parameters of the radar network and present the preliminary observation results obtained during trial operations. The observations results show that the CN‐DARN can monitor ionosphere disturbances effectively over this region; moreover, the observations can be combined with those in the Western Hemisphere to create a comprehensive picture of large‐scale features in geospace. Key Points: The Chinese Dual Auroral Radar Network (CN‐DARN) consists of three pairs of newly constructed radar facilities in northern ChinaThis paper details the hardware, key parameters and preliminary detection results of the CN‐DARNThe CN‐DARN achieves continuous detection of the mid‐ and high‐latitude ionosphere in Asia [ABSTRACT FROM AUTHOR]

In this work, we compare the single chain dynamic structure factors for five different polymers: polyolefins (PE and PEP), poly-dienes (PB and PI), and a polyether (PEO). For this purpose, we have extended the De Gennes approximation for the dynamic structure factor. We describe the single chain dynamic structure factor in multiplying the coherent scattering functions for local reptation and Rouse motion within the Rouse blob. Important results are (i) the simple De Gennes structure factor S(Q, t)DG approximates within a few Å the outcome for the tube diameter of the more elaborate structure factor (exception PI); (ii) the extended De Gennes structure factor together with the Rouse blob describes the neutron spin echo spectra from the different polymers over the complete momentum transfer range and the full time regime from early Rouse motion to local reptation; and (iii) the representation of the scattering functions could significantly be improved by introducing non-Gaussianity corrections to the Rouse-blob dynamics. (iv) The microscopic tube step length in all cases is significantly larger than the rheological one; further tweaking the relation between tube length and entanglement blob size may indicate a possible trend toward an anisotropic lean tube with a step-length larger than the lateral extension. (v) All considered polymer data coincide after proper (Q, t) scaling to a universal behavior according to the length scale of the tube, while the relevant time scale is the entanglement time τe. (vi) In terms of the packing model, the required number of chains spanning the entanglement volume consistently is about 40% larger than that obtained from rheology. [ABSTRACT FROM AUTHOR]

In this work, we show that the use of silica nanoparticles improves the imaging and 3D-morphological measurement down to nanometer thicknesses of fixed cells in solution with picosecond ultrasonics (PU). Synchronized ultrafast fs-laser pulses are used to generate coherent acoustic phonons (CAPs) that evoke the Brillouin light scattering and enable the recording of the time-resolved Brillouin oscillations along with the propagation of the acoustic nanopulses through a thin transparent cell in solution. Silica nanoparticles, whose size matches the phonon wavelength at the frequency of the Brillouin scattering in the solution, are used to strongly scatter the CAPs in the solution. Suppressing the Brillouin signature of the surrounding liquid, this protocol improves significantly the PU imaging and makes it possible to measure the mechanical properties of a transparent cell, including the thin peripheral region where the thickness is less than the Brillouin wavelength, equal to half the probe light wavelength in the cell, and where crucial interaction of the cell with its surroundings occurs. We present experimental evidence of the considerable improvement in the cartography of the entire cell using nanoparticles. The intricate frequency dependence of Brillouin scattering and of resonances for a very thin cell is analyzed using a semi-analytical model leading to the challenging measurement of the 3D-morphology of the immersed cell at thicknesses down to 1 / 9 of the optical wavelength. [ABSTRACT FROM AUTHOR]

Coherent X-ray scattering (CXS) techniques are capable of interrogating dynamics of nano- to mesoscale materials systems at time scales spanning several orders of magnitude. However, obtaining accurate theoretical descriptions of complex dynamics is often limited by one or more factors—the ability to visualize dynamics in real space, computational cost of high-fidelity simulations, and effectiveness of approximate or phenomenological models. In this work, we develop a data-driven framework to uncover mechanistic models of dynamics directly from time-resolved CXS measurements without solving the phase reconstruction problem for the entire time series of diffraction patterns. Our approach uses neural differential equations to parameterize unknown real-space dynamics and implements a computational scattering forward model to relate real-space predictions to reciprocal-space observations. This method is shown to recover the dynamics of several computational model systems under various simulated conditions of measurement resolution and noise. Moreover, the trained model enables estimation of long-term dynamics well beyond the maximum observation time, which can be used to inform and refine experimental parameters in practice. Finally, we demonstrate an experimental proof-of-concept by applying our framework to recover the probe trajectory from a ptychographic scan. Our proposed framework bridges the wide existing gap between approximate models and complex data. [ABSTRACT FROM AUTHOR]

This study investigates the tribological properties of graphite foils (GF) with densities of 1.0, 1.3, and 1.6 g/cm3, produced from purified natural graphite of different particle sizes (40–80 μm, 160–200 μm, >500 μm). Surface roughness was measured after cold rolling and friction testing at static (0.001 mm/s) and dynamic conditions (0.1 Hz and 1 Hz). Results showed that static friction tests yielded similar roughness values (Sa ≈ 0.5–0.7 μm, Sq ≈ 0.5–1.0 μm) across all densities and particle sizes. Dynamic friction tests revealed increased roughness (Sa from 0.7 to 3.5 μm, Sq from 1.0 to 6.0–7.0 μm). Friction coefficients (µ) decreased with higher sliding speeds, ranging from 0.22 to 0.13. GF with 40–80 μm particles had the lowest friction coefficient (µ = 0.13–0.15), while 160–200 μm particles had the highest (µ = 0.15–0.22). Density changes had minimal impact on friction for the 40–80 μm fraction but reduced friction for the 160–200 μm fraction. Young's modulus increased with density and decreased with particle size, showing values from 127–274 MPa for 40–80 μm, 104–212 MPa for 160–200 μm, and 82–184 MPa for >500 μm. The stress–strain state in the graphite foil samples was simulated under normal and tangential loads. This makes it possible to investigate the effect of the anisotropy of the material on the stress concentration inside the sample, as well as to estimate the elasticity modulus under normal compression. Structural analyses indicated greater plastic deformation in GF with 40–80 μm particles, reducing coherent-scattering region size from 28 nm to 24 nm. GF samples from 160–200 μm and >500 μm fractions showed similar changes, expanding with density increase from 18 nm to 22 nm. Misorientation angles of GF nanocrystallites decreased from 30° to 27° along the rolling direction (RD). The coherent scattering regions of GF with 40–80 μm particles increased, but no significant changes in the coherent scattering regions were observed for the 160–200 μm and >500 μm fractions during dynamic friction tests. Microstrains and residual macrostresses in GF increased with density for all fractions, expanding under higher friction-induced loads. Higher values of both stresses indicate a higher level of accumulated deformation, which appears to be an additional factor affecting the samples during friction testing. This is reflected in the correlation of the results with the roughness and friction coefficient data of the tested samples. [ABSTRACT FROM AUTHOR]

In this work, the effect of thermal annealing on the phase composition, surface morphology, and structural, substructural, optical, and electrical properties of multilayer structures based on p-NiO/n-ZnO heterojunctions obtained by spraying molecular solutions (spray-pyrolysis) is determined. After deposition, the samples were annealed in vacuum at temperatures of 300, 400, 500 °C during 60 min. The multilayer structure was studied using X-ray diffraction analysis, scanning electron microscopy, Hall effect, and optical spectroscopy. The dark current–voltage characteristics of the heterojunctions were also measured. These studies made it possible to determine the main structural, morphological, electrical, and optical properties of the films, such as crystal lattice parameters, dimensions of the coherent scattering regions, microdeformation level, density of dislocations, and band gap width depending on the annealing temperature. The energy band diagram of heterojunctions was constructed from the Anderson and Van Ruyven models. [ABSTRACT FROM AUTHOR]

The influence of modernized three-electrode ion-plasma sputtering of a complex Fe–Si–B– (Cu, Nb)/(Ni, Mo) target on the structure and properties of sputtered films was studied. The formation of amorphous and nanocrystalline phases in Fe73Si15.8B7.2-(Cu, Nb)4 and Fe78.5Si6B14-(Ni, Mo)1.5 films with a coherent scattering region size of 1.6 nm and 12 nm, respectively, was established as a result of a modernized three-electrode ion - plasma sputtering. The thermal stability of metastable states of films as well as electrical and magnetic properties of freshly prepared and heat-treated films has been investigated. The conditions for obtaining films with low values of the temperature coefficient of electrical resistance (−0.9∙10−5 K−1) and coercive force (HC ∼11 A/m) have been determined. [ABSTRACT FROM AUTHOR]

With the use of modernized industrial vacuum installations, a series of test samples of cadmium telluride films was produced by the method of thermal vacuum evaporation on glass substrates without a sublayer of transparent conductive oxide, with a sublayer of conductive oxide, and on molybdenum foil substrates to study the influence of the substrate material on the structural parameters of the test samples. The study of the structure was carried out by the method of X-ray diffractometric analysis, the parameters of the lattice, the sizes of the regions of coherent scattering and the texture coefficient of the film were calculated. Based on the results of research into the structural parameters of samples made on a glass substrate, the presence of a cubic phase of cadmium telluride was established. It is shown that when the temperature of the substrate increases, the texture of the samples increases and the presence of tensile stresses is observed, since the lattice period of the cubic phase is significantly higher than that of the tabular phase. For a sample obtained on a glass substrate with a layer of transparent conductive ITO oxide at a substrate temperature of 200 °C, the presence of two hexagonal phases H1 and H2 and a cubic phase C was established. The samples obtained on a molybdenum foil substrate contain almost entirely the cubic CdTe phase only in very thin sample no. 1 traces of the hexagonal phase are present. For the first thinnest sample, only one main diffraction peak of the cubic phase is observed, which can be explained by the fact that in the initial stages of the film growth, it grows as a highly textured cubic phase with the possible presence of some hexagonal phase. From the analysis of the obtained results, it can be noted that the samples obtained on the molybdenum substrate have a lattice parameter closest to the table data – 6.482-6.483 Å. The structural differences observed between the studied samples are due to the fact that they have a different preferred orientation, which is most likely due to a change in the sputtering speed. [ABSTRACT FROM AUTHOR]

This study considers critical data reduction steps and data analysis approaches required to determine explicitly the atomic arrangements in nanoparticles from time‐of‐flight neutron total scattering. A practical procedure is described for removing parasitic backgrounds caused by the incoherent scattering of hydrogen inevitably present in most nanoparticle samples and normalizing the recovered coherent scattering intensities onto an absolute scale. A model‐free analysis is presented of a pair‐distribution function derived from total scattering that can be used to determine thermal expansion coefficients and particle sizes directly from experimental data without knowledge of the material's structure. Finally, atomistic whole‐nanoparticle refinements of yttrium‐doped ceria nanoparticles from neutron total‐scattering data are demonstrated using the reverse Monte Carlo method implemented in the RMCProfile software. These results reveal a strong dependence of the cation–oxygen and oxygen–oxygen distances on the coordination numbers, which leads to gradients of these distances near the particle surface. The details are dependent on the surface coverage by ligands and adsorbates and on the structure of grain boundaries in nanocrystalline agglomerates. The refined models confirm the expectations of more substantial disorder at particle surfaces, with a distorted surface layer extending over several coordination shells. The results highlight the feasibility of whole‐nanoparticle refinements from neutron data, calling for further development of data reduction and analysis procedures. [ABSTRACT FROM AUTHOR]

Coherent Raman Scattering Imaging offers quick and surface‐sensitive large‐area scans of specimens including fingerprinting of the substances, combined with low detection limits. By using a multi‐photon process, it offers orders of magnitude stronger surface signal in comparison to spontaneous Raman (SR) and fluorescence signals of the substrate are avoided by the detection principle and the near‐infrared laser wavelength. By exciting at a specific wavelength instead of measuring whole spectra the measurement time is remarkably reduced. Here, detecting organic thin films on glass surfaces is investigated. The detection of those thin films is relevant for production processes where the interfacial layer is influenced by the low surface energy of contaminants, especially polysiloxanes. The samples are manufactured by pipetting diluted polydimethylsiloxane (PDMS) in heptane in various concentrations (1%, 0.1%, 0.01%, and 0.001%) on glass substrates. After evaporation of the solvent, thin films of the silicone remain. The resulting average coverage of the thin films equals 100–0.1 μg cm−2. Measurements determine the detectability threshold with SR to 10 μg cm−2, while the acquired spectrum is used to determine characteristic peaks for the pump laser. Afterwards the samples are imaged at those wavenumbers with Coherent Raman Scattering (CRS) Imaging techniques providing a chemically‐specific contrast. [ABSTRACT FROM AUTHOR]

This paper presents the effects of annealing on the phase and chemical composition, surface morphology, structure, substructure, and optical properties of SnS films obtained using the nanoink spraying method based on a suspension of nanoparticles. SnS nanoparticles were synthesized in an aqueous ammonia solution using triethanolamine. After the ink was applied to the glass substrates, the samples were annealed at 150, 200, 250, 300, 350, 400, 450, and 500 °C for 30 min in a mixture of argon and oxygen atmosphere. Thin layers of tin sulfide were studied using energy-dispersive EDX, X-ray diffraction analysis, SEM microscopy, Raman spectroscopy, and optical spectroscopy. The films are nanocrystalline and contain an orthorhombic SnS phase. In the films annealed at a temperature Ta ≥ 450 °C, tin oxide was detected diffractometrically. These studies also explored the determination of the main structural parameters of the films, such as the texture, period of the crystal lattice, sizes of the coherent scattering regions, and the level of microdeformations depending on the annealing temperature. The optimal conditions for the annealing of the films were investigated. [ABSTRACT FROM AUTHOR]

The quasiparticle propagation away from the track of a highly ionizing particle in superfluid helium at low temperatures has previously been shown to exhibit anisotropy. We discuss the mechanism responsible for this behavior and show that it occurs for nuclear scattering by dark matter for recoil energies down to a few keV, and perhaps lower. This directionality makes it possible to search for and distinguish galactic dark matter with interaction cross sections that reach into the neutrino fog where coherent neutrino-nucleus scattering presents an irreducible background. [ABSTRACT FROM AUTHOR]

Glassy solids evolve towards lower-energy structural states by physical aging. This can be characterized by structural relaxation times, the assessment of which is essential for understanding the glass' time-dependent property changes. Conducted over short times, a continuous increase of relaxation times with time is seen, suggesting a time-dependent dissipative transport mechanism. By focusing on micro-structural rearrangements at the atomic-scale, we demonstrate the emergence of sub-diffusive anomalous transport and therefore temporal fractional diffusion in a metallic glass, which we track via coherent x-ray scattering conducted over more than 300,000 s. At the longest probed decorrelation times, a transition from classical stretched exponential to a power-law behavior occurs, which in concert with atomistic simulations reveals collective and intermittent atomic motion. Our observations give a physical basis for classical stretched exponential relaxation behavior, uncover a new power-law governed collective transport regime for metallic glasses at long and practically relevant time-scales, and demonstrate a rich and highly non-monotonous aging response in a glassy solid, thereby challenging the common framework of homogeneous aging and atomic scale diffusion. In metallic glasses, atomic-scale transport strongly affects the materials properties and thus performance in applications. Here the authors present the intermittent character of structural relaxation connected to microstructural heterogeneity, and power-law behavior at long time scales resulting from collective and correlated atomic motion. [ABSTRACT FROM AUTHOR]

The unusual stripe‐like scattered echoes were observed by the Hainan Coherent Scatter Phased Array Radar (HCOPAR) in the nigh of 9 Sep. 2017. There were parallel stripes with the interval of ∼33 min appearing from 12:57 to 17:50 UT. While the emergence of the scattered echoes, the Hainan Digisonde has observed the Spread‐F, and the Total Electron Content (TEC) maps recorded by the Global Navigation Satellite System (GNSS) in China show that there was no Equatorial Plasma Bubble (EPB), but the Medium‐Scale Traveling Ionospheric Disturbance (MSTID) traveled southwestward. The spatial and temporal distributions of the stripe‐like echoes and the MSTID show great consistency, indicating that the F‐region Field‐Aligned Irregularities were generated in the wave peaks and troughs of the MSTID. The MSTID has decayed greatly while reaching the HCOPAR, and the echo pattern is determined by the wave features of the MSTID. Key Points: Unusual stripe‐like echoes scattered from nighttime F‐region Field‐Aligned Irregularities were observed at low‐latitudesThe stripe‐like echo pattern exhibits a good correlation with the Medium‐Scale Traveling Ionospheric Disturbance (MSTID) observed in the Total Electron Content mapsThe scattered echoes were generated in wave troughs and peaks of the MSTID, and the echo pattern is determined by the wave features [ABSTRACT FROM AUTHOR]

Observations of coherent scatter from patchy sporadic E layers in the subauroral zone made with a 30‐MHz coherent scatter radar imager are presented. The quasiperiodic (QP) echoes are similar to what has been observed at middle latitudes but with some differences. The echoes arise from bands of scatterers aligned mainly northwest to southeast and propagating to the southwest. A notable difference from observations at middle latitudes is the appearance of secondary irregularities or braids oriented obliquely to the primary bands and propagating mainly northward along them. We present a spectral simulation of the patchy layers that describes neutral atmospheric dynamics with the incompressible Navier Stokes equations and plasma dynamics with an extended MHD model. The simulation is initialized with turning shears in the form of an Ekman spiral. Ekman‐type instability deforms the sporadic E layer through compressible and incompressible motion. The layer ultimately exhibits both the QP bands and the braids, consequences mainly of primary and secondary neutral dynamic instability. Vorticity due to dynamic instability is an important source of structuring in the sporadic E layer. Key Points: Radar observations and theory of subauroral sporadic E layer irregularities are presentedCoherent scatter from the layers presents as primary bands of irreguarities with secondary, oblique, braided structureSimulations of neutral dynamic instability associated with turning shears in Es layers consistent with observations [ABSTRACT FROM AUTHOR]

Flexible graphite foils with varying thicknesses (S = 282 ± 5 μm, M = 494 ± 7 μm, L = 746 ± 8 μm) and an initial density of 0.70 g/cm3 were obtained using the nitrate method. The specific electrical and thermal conductivity of these foils were investigated. As the density increased from 0.70 g/cm3 to 1.75 g/cm3, the specific electrical conductivity increased from 69 to 192 kS/m and the thermal conductivity increased from 109 to 326 W/(m·K) due to the rolling of graphite foils. The study showed that conductivity and anisotropy depend on the shape, orientation, and contact area of thermally expanded graphite (TEG) mesoparticles (mesostructural factor), and the crystal structure of nanocrystallites (nanostructural factor). A proposed mesostructural model explained these increases, with denser foils showing elongated, narrowed TEG particles and larger contact areas, confirmed by electron microscopy results. For graphite foils 200 and 750 μm thick, increased density led to a larger coherent scattering region, likely due to the rotation of graphite mesoparticles under mechanical action, while thinner foils (<200 μm) with densities > 1.7 g/cm3 showed increased plastic deformation, indicated by a sharp reduction in the coherent scattering region size. This was also evident from the decrease in misorientation angles with increasing density. Rolling reduced nanocrystallite misorientation angles along the rolling direction compared to the transverse direction (TD) (for 1.75 g/cm3 density ΔMA = 1.2° (S), 2.6° (M), and 2.4° (L)), explaining the observed anisotropy in the electrical and mechanical properties of the rolled graphite foils. X-ray analysis confirmed the preferred nanocrystallite orientation and anisotropy coefficients (A) using Kearns parameters, which aligned well with experimental measurements (for L series foils calculated as: A0.70 = 1.05, A1.30 = 1.10, and A1.75 = 1.16). These calculated values corresponded well with the experimental measurements of specific electrical conductivity, where the anisotropy coefficient changed from 1.00 to 1.16 and mechanical properties varied from 0.98 to 1.13. [ABSTRACT FROM AUTHOR]

In recent years, there has been increasing interest in developing detectors which are sensitive to sub-GeV dark matter and low-energy events from coherent neutrino scattering. Due to carbon's light atomic weight and its tendency to form crystals with high-energy, long-lived phonon modes, carbon-based crystals (including diamond and silicon carbide (SiC)) present themselves as natural target materials for scattering-based searches in this regime. We present our preliminary results in adapting our TES-based detectors to these substrates, specifically 4-H SiC and polycrystalline diamond. We focus on our fabrication efforts, specifically tuning the transition temperature ( T C ) of tungsten films sputtered on these materials, as well as our advancement toward fabricating and testing devices on these substrates. [ABSTRACT FROM AUTHOR]

As one of the popular coherent Raman scattering techniques, stimulated Raman scattering (SRS) has made significant progress in recent years, especially in label-free biological imaging. Polarization provides an additional degree of freedom to manipulate the SRS process. In previous studies, only linearly polarized SRS was fully investigated, in which both pump and Stokes laser fields are linearly polarized. Here, we theoretically analyzed the SRS process excited by two circularly polarized laser fields and then experimentally demonstrated it by taking a spherical symmetric CH4 molecule as a model system. The experimental results are in good agreement with the theoretical ones. It is shown that circularly polarized SRS (CP-SRS) has unique characteristics different from linear polarization. When the handedness of circular polarization states of two laser fields is the same, CP-SRS further suppresses the depolarized vibrational band while keeping the polarized band almost unaffected. On the other hand, when the handedness is opposite, CP-SRS enhances the depolarized band while suppressing the polarized band. Therefore, the CP-SRS not only allows us to resolve the symmetry of vibrational modes but also can enhance vibrational contrast based on symmetry selectivity by suppressing or enhancing the signal from a specific vibrational mode. These results will have potential applications in improving chemical selectivity and imaging contrast as well as spectral resolution SRS microscopy. In addition, the CP-SRS has the ability to determine the depolarization ratio ρ and identify the overlapping Raman bands. [ABSTRACT FROM AUTHOR]

In this study, we investigate the time–frequency-resolved resonant photon emission from a molecular vibrational oscillator driven by a monochromatic coherent external field. Using the complex spectral analysis of the Liouvillian, which integrates irreversible dissipative phenomena into quantum theory, we elucidate the fundamental processes of photon emission. Indeed, our analytical approach successfully decomposes the emission spectrum into two intrinsic contributions: one from a resonance eigenmode and another from continuous eigenmodes. These components are responsible for incoherent luminescence and coherent scattering photon emission processes, respectively. Our results show that while spontaneous emission dominates in the early stages of the emission process, coherent scattering gradually becomes more pronounced with time. Furthermore, destructive quantum interference between the two components plays a key role in determining the overall shape of the emission spectrum. [ABSTRACT FROM AUTHOR]

The influence of the structure of nickel-zinc ferrite powders on the behavior of magnetic phase transitions is studied in the Curie point region. The samples with a controlled set of microstresses and sizes of coherent scattering regions are prepared by dry milling of the synthesized ferrites in a ball mill at the rates of 500, 1000, 1500 rev/min for 15, 30, and 60 min. Their structure is examined by the method of X-ray diffraction. An analysis of the magnetic phase transitions in the Curie temperature region is performed using thermogravimetry in a constant magnetic field (thermomagnetometry). The regularities of variations of the powder structure parameters as a function of the frequency-time dry milling modes are identified. A linear regression dependence of the amplitude of the weight section in the thermogravimetry curve in the Curie point region on the value of microstresses and the size of coherent scattering regions is revealed. The findings allow taking account of the influence of these structural characteristics on the shape of the thermograms in the region of magnetic phase transitions and provide a more precise interpretation of the thermomagnetometric results. [ABSTRACT FROM AUTHOR]

Physical optics simulations for beamlines and experiments allow users to test experiment feasibility and optimize beamline settings ahead of beam time in order to optimize valuable beam time at synchrotron light sources like NSLS-II. Further, such simulations also help to develop and test experimental data processing methods and software in advance. The Synchrotron Radiation Workshop (SRW) software package supports such complex simulations. We demonstrate how recent developments in SRW significantly improve the efficiency of physical optics simulations, such as end-to-end simulations of time-dependent X-ray photon correlation spectroscopy experiments with partially coherent undulator radiation (UR). The molecular dynamics simulation code LAMMPS was chosen to model the sample: a solution of silica nanoparticles in water at room temperature. Real-space distributions of nanoparticles produced by LAMMPS were imported into SRW and used to simulate scattering patterns of partially coherent hard X-ray UR from such a sample at the detector. The partially coherent UR illuminating the sample can be represented by a set of orthogonal coherent modes obtained by simulation of emission and propagation of this radiation through the coherent hard X-ray (CHX) scattering beamline followed by a coherent-mode decomposition. GPU acceleration is added for several key functions of SRW used in propagation from sample to detector, further improving the speed of the calculations. The accuracy of this simulation is benchmarked by comparison with experimental data. [ABSTRACT FROM AUTHOR]

Distinguishing two objects or point sources located closer than the Rayleigh distance is impossible in conventional microscopy. Understandably, the task becomes increasingly harder with a growing number of particles placed in close proximity. It has been recently demonstrated that subwavelength nanoparticles in closely packed clusters can be counted by AI-enabled analysis of the diffraction patterns of coherent light scattered by the cluster. Here, we show that deep learning analysis can return the actual positions of nanoparticles in the cluster. The Pearson correlation coefficient between the ground truth and reconstructed positions of nanoparticles exceeds 0.7 for clusters of ten nanoparticles and 0.8 for clusters of two nanoparticles of 0.16λ in diameter, even if they are separated by distances below the Rayleigh resolution limit of 0.68λ, corresponding to a lens with numerical aperture NA = 0.9. [ABSTRACT FROM AUTHOR]

Landslides recurrently cause severe damage and, in some cases, the full disruption of many highways in mountainous areas, which can last from a few days to even months. Thus, there is a high demand for monitoring tools and precipitation data to support highway alignment selections before construction. In this study, we proposed a new system highway alignment selection method based on coherent scatter InSAR (CSI) and ~1 km high-spatial-resolution precipitation (HSRP) analysis. Prior to the CSI, we calculated and analyzed the feasibility of Sentinel-1A ascending and descending data. To illustrate the performance of the CSI, CSI and SBAS–InSAR were both utilized to monitor 80 slow-moving landslides, which were identified by optical remote-sensing interpretation and field investigation, along the Barkam–Kangting Highway Corridor (BKHC) in southwestern China, relying on 56 Sentinel-1A descending images from September 2019 to September 2021. The results reveal that CSI has clearer deformation signals and more measurement points (MPs) than SBAS-InSAR. And the maximum cumulative displacements and rates of the landslides reach −75 mm and −64 mm/year within the monitoring period (CSI results), respectively. Furthermore, the rates of the landslides near the Jinchuan River are higher than those of the landslides far from the river. Subsequently, to optimize the highway alignment selection, we analyzed the spatiotemporal evolution characteristics of feature points on a typical landslide by combining the −1 km HSRP, which was calculated from the 30′ Climatic Research Unit (CRU) time-series datasets, with the climatology datasets of WorldClim using delta spatial downscaling. The analysis shows that the sliding rates of landslides augment from the back edge to the tongue because of fluvial erosion and that accelerated sliding is highly related to the intense precipitation between April and September each year (ASP). Consequently, three solution types were established in our method by setting thresholds for the deformation rates and ASPs of every landslide. Afterward, the risk-optimal alignment selection of the BKHC was finalized according to the solution types and consideration of the construction's possible impacts. Ultimately, the major problems and challenges for our method were discussed, and conclusions were given. [ABSTRACT FROM AUTHOR]

The effect of gamma radiation dose on the structure of an ethylene–tetrafluoroethylene copolymer has been studied. The copolymer powder has a triclinic crystal structure with space group P-1 and unit cell parameters of a = 8.84 Å, b = 5.34 Å, c = 4.90 Å, α = 99.11°, β = 85.84°, and γ = 90.89°. The coherent scattering region of the copolymer linearly increases from 4.3 to 6.8 nm with an increase in the absorbed gamma radiation dose to 2000 kGy. The degree of crystallinity of the copolymer decreases by 2.1% after irradiation with a dose of up to 100 kGy; after that, with an increase in the dose to 2000 kGy, the degree of crystallinity increases. The absence of significant changes in the crystal structure parameters of the copolymer after irradiation with a dose of up to 2000 kGy suggests that the copolymer crystal structure is resistant to radiation. [ABSTRACT FROM AUTHOR]

The influence of the interference between coherent processes in third-order nonlinear Raman scattering on the spectral shapes of Raman-scattered light waves is numerically modeled and discussed in the cases of commonly used coherent Raman spectroscopy techniques. The effects on the lineshapes depending on the laser intensity are analyzed for the coherent Raman spectroscopy performed via the excitation of molecular systems with focused laser pulses at high intensities. In this case, the interplay between the coherent processes in nonlinear Raman scattering, as well as laser power-induced resonance effects, may be significant and should be taken into account in the spectral lineshape analysis in coherent Raman spectroscopy and its related applications, since the coherent Raman spectra may be considerably modified. [ABSTRACT FROM AUTHOR]

Coherent scattering is the theoretical basis of X-ray diffraction, which is widely used in the field of materials. A functional module to calculate the nondestructive testing of photon-atomic and photon-molecular coherent scattering cross sections is developed in the nuclear data processing code NECP-Atlas. The photon-atomic coherent scattering cross section is processed in NECP-Atlas with the same method as that of NJOY2016. In practice, photon interacts with materials which usually consist of numerous polyatomic molecules. Therefore, the photon-molecular coherent scattering cross sections should be calculated instead of photon-atomic coherent scattering cross sections to acquire more accurate simulated results. First, the independent atom model (IAM) was implemented to calculate the photon-molecular coherent scattering cross sections with the assumption that the atom was isolated. This approximation works well when the momentum transfer of incident photons is large. At small momentum transfer, the interference effects of various atoms cannot be ignored. Then, the molecular interference model was introduced to consider the influence on angular distribution of secondary photons due to the interference effects. The molecular interference functions of water and ethanol were simulated using molecular dynamics simulation, and then applied in the ACE library. The atomic form factors of the atoms in water and ethanol molecules were modified by the molecular interference function. To quantify the influence of molecular interference effects on angular distribution of secondary photons, an imaging system was simulated. Numerical results show that the molecular interference effects have a significantly influence on the angular distribution of photons at small momentum transfer, while at large momentum transfer, the molecular interference effects can be ignored.

We outline a machine learning strategy for quantitively determining the conformation of AB-type diblock copolymers with excluded volume effects using small angle scattering. Complemented by computer simulations, a correlation matrix connecting conformations of different copolymers according to their scattering features is established on the mathematical framework of a Gaussian process, a multivariate extension of the familiar univariate Gaussian distribution. We show that the relevant conformational characteristics of copolymers can be probabilistically inferred from their coherent scattering cross sections without any restriction imposed by model assumptions. This work not only facilitates the quantitative structural analysis of copolymer solutions but also provides the reliable benchmarking for the related theoretical development of scattering functions. [ABSTRACT FROM AUTHOR]

The physical and mechanical properties and structural condition of flexible graphite foils produced by processing natural graphite with nitric acid, hydrolysis, thermal expansion of graphite and subsequent rolling were studied. The processes of obtaining materials and changing their characteristics has been thoroughly described and demonstrated. The structural transformations of graphite in the manufacture of foils were studied by X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). A decrease in the average size of the coherent scattering regions (CSR) of nanocrystallites was revealed during the transition from natural graphite to thermally expanded graphite from 57.3 nm to 20.5 nm at a temperature of 900 °C. The rolling pressure ranged from 0.05 MPa to 72.5 MPa. The thickness of the flexible graphite foils varied from 0.11 mm to 0.75 mm, the density—from 0.70 to 1.75 g/cm3. It was shown that with an increase in density within these limits, the compressibility of the graphite foil decreased from 65% to 9%, the recoverability increased from 5% to 60%, and the resiliency decreased from 10% to 6%, which is explained by the structural features of nanocrystallites. The properties' anisotropy of graphite foils was studied. The tensile strength increased with increasing density from 3.0 MPa (ρ = 0.7 g/cm3) to 14.0 MPa (ρ = 1.75 g/cm3) both in the rolling direction L and across T. At the same time, the anisotropy of physical and mechanical properties increased with an increase in density along L and T to 12% with absolute values of 14.0 MPa against 12.5 MPa at a thickness of 200 μm. Expressed anisotropy was observed along L and T when studying the misorientation angles of nanocrystallites: at ρ = 0.7 g/cm3, it was from 13.4° to 14.4° (up to 5% at the same thickness); at ρ = 1.3 g/cm3—from 11.0° to 12.8° (up to 7%); at ρ = 1.75 g/cm3—from 10.9° to 12.4° (up to 11%). It was found that in graphite foils, there was an increase in the coherent scattering regions in nanocrystallites with an increase in density from 24.8 nm to 49.6 nm. The observed effect can be explained by the coagulation of nanocrystallites by enhancing the Van der Waals interaction between the surface planes of coaxial nanocrystallites, which is accompanied by an increase in microstrains. The results obtained can help discover the mechanism of deformation of porous graphite foils. The obtained results can help discover the deformation mechanism of porous graphite foils. We assume that this will help predict the material behavior under industrial operating conditions of products based flexible graphite foils. [ABSTRACT FROM AUTHOR]

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Obtaining precise and rapid crop height is essential to facilitate agricultural production services, field management, disaster monitoring, and yield assessment. With the capability to penetrate vegetation and record vertical structure information, Polarimetric Synthetic Aperture Radar (PolSAR) holds significant potential for application in vegetation height inversion. The Water Cloud Model (WCM) and its enhanced versions are extensively utilized for estimating crop heights from PolSAR data owing to their physical significance and simplicity. However, the method is not practical for stalk crops due to the neglect of double-bounce scattering considerations. Therefore, according to the growth characteristics of stalk crops, a three-component polarimetric coherent backscattering model considering crop target double-bounce scattering is established by simplifying the Random Volume over Ground (RVoG) coherent scattering model. The empirical coefficient is introduced to simplify the model into a semi-empirical for crop height inversion. The suitability of applying the RVoG-B three-component model for crop height inversion at the early stage in corn fields was assessed using Multi-temporal C-band PolSAR RADARSAT-2 data in three polarimetric channels. The results show that the HV channel exhibits superior potential in inverting the height of corn compared with the HH and the VV channels. The results of corn height inversion demonstrate that the RVoG-B three-component semi-empirical model performs effectively in estimating corn height, with its inversion accuracy having an RMSE ranging from 11.66cm to 24.51cm. This study demonstrates the potential application of the RVoG-B three-component semi-empirical model for inverting crop height at the early stage dominated by double-bounce scattering. [ABSTRACT FROM AUTHOR]

More than 15 years ago, the study of nanodiamond (ND) powders as a material for designing reflectors of very cold neutrons (VCNs) and cold neutrons (CNs) began. Such reflectors can significantly increase the efficiency of using such neutrons and expand the scope of their application for solving applied and fundamental problems. This review considers the principle of operation of VCN and CN reflectors based on ND powders and their advantages. Information is presented on the performed experimental and theoretical studies of the effect of the size, structure, and composition of NDs on the efficiency of reflectors. Methods of chemical and mechanical treatments of powders in order to modify their chemical composition and structure are discussed. The aim is to avoid, or at least to decrease, the neutron inelastic scatterers and absorbers (mainly hydrogen atoms but also metallic impurities and nitrogen) as well as to enhance coherent elastic scattering (to destroy ND clusters and sp2 carbon shells on the ND surface that result from the preparation of NDs). Issues requiring further study are identified. They include deeper purification of NDs from impurities that can be activated in high radiation fluxes, the stability of NDs in high radiation fluxes, and upscaling methods for producing larger quantities of ND powders. Possible ways of solving these problems are proposed. [ABSTRACT FROM AUTHOR]

The effects of physiological and pathogenic factors on the crystal structure of calcium hydroxyapatite Ca10(PO4)6(OH)2 in mineralized bone tissues are considered. The unit cell constants of bioapatite, the unit cell deformation, and the crystallite sizes in different groups of bone tissues were analyzed based on the results of X-ray diffraction studies. The main mechanisms responsible for spatial-temporal changes in bone nanostructures were revealed. It was demonstrated that, along with violations of the stoichiometry, an important role is played by the crystallite sizes, estimated as the coherent scattering regions, the number of atoms in which differs by more than two orders of magnitude, and electrostatic interactions between the unbalanced charges of nanocrystallites and hydrated nanolayers of the mineral matrix. [ABSTRACT FROM AUTHOR]

An empirical study assessing the suitability of laser speckle patterns for use in experimental mechanics research conducted at hypersonic conditions is presented. Speckle patterns generated via coherent optical scattering from a gold-coated graphite surface inserted into a Mach 10 air stream were collected and analyzed using Computer-Aided Speckle Interferometry using two methodologies: a typical spanwise approach involving increasing temporal span between image pairs, and a sequential approach that utilizes a combination of temporal re-referencing and spatial resampling. Results were characterized for spatial-temporal stability and variance. Our observations demonstrate that optical methods relying on stable and properly formed speckle patterns can be used in a hypersonic regime at various Reynolds numbers and common camera frame rates, but the technique is sensitive to the conditions of the airflow and the processing methodology chosen. [ABSTRACT FROM AUTHOR]

It is demonstrated that Kikuchi features become clearly visible if reflection high‐energy electron diffraction (RHEED) patterns are filtered using digital image processing software. The results of such pattern transformations are shown for SrTiO3 with mixed surface termination for data collected at different azimuths of the incident electron beam. A simplified analytical approach for the theoretical description of filtered Kikuchi patterns is proposed and discussed. Some examples of raw and filtered patterns for thin films are shown. RHEED patterns may be treated as a result of coherent and incoherent scattering of electron waves. The effects of coherent scattering may be considered as those occurring due to wave diffraction by an idealized crystal and, usually, only effects of this type are analysed to obtain structural information on samples investigated with the use of RHEED. However, some incoherent scattering effects mostly caused by thermal vibrations of atoms, known as Kikuchi effects, may also be a source of valuable information on the arrangements of atoms near the surface. Typically, for the case of RHEED, Kikuchi features are hidden in the intensity background and researchers cannot easily recognize them. In this paper, it is shown that the visibility of features of this type can be substantially enhanced using computer graphics methods. [ABSTRACT FROM AUTHOR]

Catalysts for the selective oxidation of ammonia to molecular nitrogen are essential for the fight against environmental pollution due to vehicle and industrial emissions. This work reports a study of Pt/TiO2-based K-modified catalysts for the selective oxidation of ammonia. The Pt/TiO2 catalysts are prepared by impregnating a commercial TiO2 support (Degussa, P25 Aeroxide) by a platinum nitrate precursor followed by depositing small amounts of potassium with variation of the precursor nature (KOH, KNO3, KCl). The influence of a promoting additive on the catalysts properties is considered using a complex of physicochemical and kinetic methods such as powder XRD, X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of NH3 (NH3-TPD), NH3+O2 temperature programmed reaction (NH3+O2-TPR). According to the XRD data, dispersed platinum particles with a coherent scattering region of no more than 5 nm are formed in the samples. The XPS data indicate that the oxidation state of platinum can be changed by varying the potassium precursor. It is shown that the potassium chloride precursor enhances the selectivity to molecular nitrogen in the temperature range up to 200 °C. The changes in the acidic properties of the sample surfaces are revealed using the NH3-TPD data, and the changes are compared with catalytic characteristics of the samples in the reaction of ammonia oxidation. [ABSTRACT FROM AUTHOR]

Non-iridescent structural plumage reflectance is a sexually selected indicator of individual quality in several bird species. However, the structural basis of individual differences remains unclear. In particular, the dominant periodicity of the quasi-ordered feather barb nanostructure is of key importance in colour generation, but no study has successfully traced back reflectance parameters, and particularly hue, to nanostructural periodicity, although this would be key to deciphering the information content of individual variation. We used matrix small-angle X-ray scattering measurements of intact, stacked feather samples from the blue tit crown to estimate the sex-dependence and individual variation of nanostructure and its effects on light reflectance. Measures of nanostructural periodicity successfully predicted brightness, ultraviolet chroma and also hue, with statistically similar effects in the two sexes. However, we also observed a lack of overall effect of the nanostructural inhomogeneity estimate on reflectance chromaticity, sex-dependent accuracy in hue prediction and strong sex-dependence in position estimation error. We suggest that reflectance attributes are modified by other feather structures in a sex-specific manner, and that within-individual variation in nanostructural parameters exists within or among feathers and this confounds the interpretation of structure–reflectance relationships at the plumage area level.

Turbulence in hollow cathodes used for space propulsion is believed to play an important role in anomalous electron transport and ion heating. In this work, the implementation of coherent Thomson scattering to identify and characterize MHz-frequency ion acoustic turbulence and kHz-frequency oscillations in the plume of a hollow cathode is achieved. In the presence of a background magnetic field of a Hall thruster, a number of unstable modes are observed. A directive ion acoustic mode propagating predominantly within a restricted angle around the magnetic field is found, exhibiting an energy scaling with wavenumber k of the form k − 5.2 ± 0.58 , which differs from the classic Kadomtsev k − 3 scaling for unmagnetized conditions. Bi-directional ion acoustic mode fluctuations propagating over a range of angles with respect to the magnetic field have been measured, possibly signifying the existence of a large-amplitude plasma wave, similar to the Buneman instability. Finally, electron density fluctuations in the kHz-frequency range, a possible consequence of drift-driven instabilities in the plane perpendicular to the magnetic field, have also been identified. These results not only are an indication of the diversity of wave types that exist in hollow cathode plumes but also point to the key role played by the presence of, and the configuration of, the magnetic field in their appearance. [ABSTRACT FROM AUTHOR]

Quantum networks have the potential to transform secure communication via quantum key distribution and enable novel concepts in distributed quantum computing and sensing. Coherent quantum light generation at telecom wavelengths is fundamental for fibre-based network implementations, but Fourier-limited emission and subnatural linewidth photons have so far only been reported from systems operating in the visible to near-infrared wavelength range. Here, we use InAs/InP quantum dots to demonstrate photons with coherence times much longer than the Fourier limit at telecom wavelength via elastic scattering of excitation laser photons. Further, we show that even the inelastically scattered photons have coherence times within the error bars of the Fourier limit. Finally, we make direct use of the minimal attenuation in fibre for these photons by measuring two-photon interference after 25 km of fibre, demonstrating finite interference visibility for photons emitted about 100,000 excitation cycles apart. Developing quantum networks would require reliable sources of coherent quantum light at telecom wavelengths. Here, the authors employ elastic scattering of excitation laser photons on InAs/InP quantum dots to demonstrate the emission of telecom photons with coherence times longer than the Fourier limit. [ABSTRACT FROM AUTHOR]

The low-altitude quasi-periodic (LQP) E-region echoes observed with the upgraded Hainan COherent scatter Phased Array Radar (HCOPAR) located in Hainan Island of China (19.5°N, 109.1°E) are presented. With the interferometry technique, interferometry equations were developed to investigate the structures of the irregularities. The results show that the plasma structures of the LQP echoes with a negative slope mainly drifted southwestward almost horizontally, but they also drifted southeastward in some striations. According to the movement of the plasma structures, we found strong wind shear in the region in which the LQP echoes were produced. Meanwhile, the periodicity of the LQP echoes may have been related to the strength of the wind shear. It is proposed that the plasma structures were most likely produced by the Kelvin–Helmholtz instability (KHI). [ABSTRACT FROM AUTHOR]

We investigate the coherence properties of a transmission electron microscope by analyzing nano-diffraction speckles originating from bulk metallic glass. The spatial correlation function of the coherent diffraction patterns, obtained in the transmission geometry, reveals the highly coherent nature of the electron probe beam and its spatial dimension incident on the sample. Quantitative agreement between the measured speckle contrast and an analytical model yields estimates for the transverse and longitudinal coherence lengths of the source. We also demonstrate that the coherence can be controlled by changing the beam convergence angle. Our findings underscore the preservation of electron beam coherence throughout the electron optics, as evidenced by the high-contrast speckles observed in the scattering patterns of the amorphous system. This study paves the way for the application of advanced coherent diffraction methodologies to investigate local structures and dynamics occurring at atomic-length scales across a diverse range of materials. [ABSTRACT FROM AUTHOR]