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The Ge-film-based photon-counting imaging detector is a key component of optical payload in space weather observation. It’s important to study the space temperature adaptability of Ge film since the performances of Ge film are extremely sensitive to the temperature. Herein, the in-situ tests are proposed to measure the resistance and stress of the Ge film at the operating temperature. It is demonstrated that the resistance decreases from 520 MΩ/□ to 124 MΩ/□ linearly between -20 °C and 80 °C, which can meet the requirement of the imaging system well. And the stress gradually releases in the thermal cycle. The ex-situ test is adopted to investigate the limited temperature adaptability and the intrinsic mechanism of performance variations. When the temperature increased to 600 °C, Ge film failed and cracked because of resistance reducing to 30 KΩ/□ and stress increasing to 504 Mpa. Meanwhile, methods were proposed to enhance the temperature adaptability of Ge film by analyzing crystal phase and optical band gap. Thus, the resistance and stress changes of Ge film in space have little effect on the performances of imaging system. The Ge film with high temperature adaptability and low stress we prepared is promising in the space observation.

Nanoparticles of cerium oxide have been synthesized by green precipitation method by the presence of Moringa oleifera leaf extract with a short reaction time of 5 h. Base on XRD analysis confirmed structure crystal of cerium oxide the formation was a cubic. CeO2NPs were discovered to have a spherical shape and an average size of 17 nm, as shown in the TEM image. The formation of CeO2NPs was furtherly proven by EDX measurement in the presence of high-intensity peaks referred to Ce and O, with no impurities. The result after FTIR analysis of the nanoparticles demonstrates the appearance of Ce–O stretching, as well as the O–N–O bending disappearance. Based on the DRS UV–Vis analysis result, the band gap energy of CeO2NPs was found to be 18% lower than the bulky size. The synthesized CeO2NPs exhibit a high antimicrobial activity in the range of 15–31 mm zone inhibition.

The growth habit of natural gas hydrate in formation pores directly influences its occurrence and distribution, which are fundamental factors for macroscopic reservoir properties. In order to simulate the hydrate growth at pore scale and demonstrate the growth process directly, microscopic visualization experiments were carried out using glass etching model and high-resolution video microscope in this work. The crystal growth behavior of methane hydrate was observed clearly in real time, and fluid state and system pressure were analyzed. On this basis, hydrate growth patterns and corresponding control mechanisms were investigated. The results show that for a static methane–water system, the hydrate crystal grew rapidly about 10 min after perturbation. The solution gas crystallized with water, forming colorless, transparent and polygonal crystal with sharp edge and smooth surface. The free gas crystallized with water at the gas–water interface first, resulting in a quick formation of hydrate crust. Then water passed through the hydrate crust slowly and crystallized with the free gas trapped inside hydrate crust. The resulting hydrates seemed to rough and honeycomb aggregations of tiny and tightly packed crystal particles. The two kinds of hydrate with different morphologies represent two typical hydrate growth patterns. For the hydrate growth pattern of solution gas–water, solution gas, which migrates to the crystal growth front driven by the concentration gradient, is in direct contact with water, leading to a fast crystal growth rate. For the crystal growth pattern of free gas–water, the preferentially formed hydrate crust at the gas–water interface not only separates the free gas from the water phase, but also selectively obstructs the passage of gas and only allows water to pass slowly, which slows down the hydrate growth process. This research is helpful to further understand the experimental phenomena at the core and field scale, explain the existing problems, and provide support for the research on the dissociation and exploitation of natural gas hydrate.

We report a simple technique for direct neutron spectroscopy using pure LaCl3 crystals. Pure LaCl3 crystals exhibit considerably better pulse shape discrimination (PSD) capabilities with relatively good energy resolution as compared with Ce-doped LaCl3 crystals. Single crystals of pure and Ce-doped LaCl3 were grown using an inhouse-developed Bridgman furnace. PSD capabilities of these crystals were investigated using 241Am and 137Cs sources. Fast neutron detection was tested using a252Cf source and three separate bands corresponding to electron, proton, and alpha were observed. The proton band induced by the 35Cl(n,p)35S reaction can be used for direct neutron spectroscopy because proton energy is proportional to incident neutron energy. Owing to good scintillation performance and excellent PSD capabilities, pure LaCl3 is a promising candidate for space detectors and other applications that necessitate gamma/fast neutron discrimination capability.

CeO2–ZrO2 mixed oxides with controlled morphologies (i.e., nanorod, nano-polyhedral and disordered shape) were synthesized through either hydrothermal or coprecipitation method, and the corresponding supported Pd/CeO2–ZrO2 catalysts were also prepared by conventional impregnation. The obtained catalysts were subjected to systematic structural/physio-chemical characterizations as well as three-way catalytic performance evaluations. The results showed that CeO2–ZrO2 mixed oxides presented different exposed crystal planes: namely disordered CZ-di mainly exposed (111) crystal planes, nanorod CZ-ro mainly exposed (111) crystal planes and few (100) crystal planes, while nano-polyhedral CZ-po exposed both (111) and (100) crystal planes. Clear structure-activity relationship could be demonstrated between the TWC (Three-way catalysts) performance of Pd/CeO2–ZrO2 and such different microstructures, as (100) and (111) crystal planes exposed by CZ-ro and CZ-po were beneficial for the surface oxygen vacancies formation, thus increasing the Pd-support interaction and effectively decreasing the light-off temperature of HC and NO elimination. On the other hand, the disordered CZ-di retained more lattice oxygen content, leading to better catalytic activity of CO elimination for the corresponding Pd/CZ-di catalyst.

The simultaneous control of crystal phase stability and one-dimensional growth has always been the major challenge for the preparation of tetragonal zirconia whiskers. In this study, we report a facile molten salt processing that utilizes CaF2 as a stabilizer and adsorbent to meet the phase and morphology requirements. The processes of stabilization, phase transition, ion adsorption and formation of special morphology involved in zirconia growth were investigated by XRD, IR, SEM, DTA-TG and TEM. By controlling the amount of CaF2 (15 wt.%) added in the reaction precursor, tetragonal zirconia whiskers with a desired aspect ratio (>16) can be synthesized, which show single crystalline nature and [001] preferred direction. Ca ions doped at low temperature inhibit the occurrence of phase transition, which allows the tetragonal structure to be retained to room temperature. The inducement and pattern of whisker growth are supposed to be F-adsorption and screw dislocation elongation, respectively. The specific selectivity of surface adsorbed ions to certain zirconia crystal planes reduces or even inhibits the epitaxial growth rate in this direction, offering a viable avenue for the morphology modulation of inorganic nanomaterials.

Based on the special physical–chemical characteristics of optical crystal in the field of aeronautics, a new anhydrous based shear-thickening polishing (ASTP) method has been proposed to restrain deliquescence and to improve physical properties for KDP machining. The ultra-precision polishing of KDP crystal is completed by ASTP. A kind of anhydrous based thickening polishing slurry (ATPS) was proposed in our work, and high-performance rheological properties were determined to achieve the ASTP of KDP crystal. A material removal model of ASTP in KDP machining is established, followed by the verification experiment of the prediction model. The maximum error of the predictive model is only 9.8%, which proves the validity of the material removal model for KDP polishing. The polishing experiments were carried out on the polishing platform developed by ourselves. The results show that the new polishing method can polish 20 mm × 20 mm × 5 mm KDP crystal and obtain a super-smooth surface with a surface roughness of 1.37 nm and high shape accuracy. The surface accuracy of polished KDP crystal reaches up to 0.68λ (RMS). The experimental results show that the ASTP is a potential ultra-precision machining method for KDP crystal.

In the present paper we report proof of consistent non monotonic lattice variation (NMLV) as a function of grain size in nanocrystalline CeO2. By analyzing more than 30 powder samples of CeO2 with grain size ranging from 5 to 200 nm which were synthesized by three different methods, it was found that in the nanocrystalline powders the unit cell parameters are smoothly varying along the decreasing of grain size with moderate contraction between 100 to 30 nm and severe expansion when the grain size become smaller than 20 nm. As a result of these two opposite trends a minimum value of unit cell parameter was detected in grain size between 25 to 50 nm. The lattice parameter change can be modeled as two global effects acting simultaneously. The first one is a contraction due to surface tension and the second one is a lattice expansion caused by ionic bonds weakening as the grain size decreases. This model can be applied to most ionic nanocrystalline materials. Consequently, it is recommended to add a new category “ambient-nano” in the crystallographic and diffraction data bases for nanomaterials with structures controlled by grain size.

Sintering mechanisms of copper nanoparticles on copper plates are investigated based on molecular dynamics (MD) simulation. In this paper, the roles of tilt grain boundaries (GBs) and Σ5 twisted GBs on sintering kinetics are considered. Regardless of the diameter of the nanoparticle sphere, it is observed that stacking faults and dislocations are formed near the GBs by crystal analysis at the early stage of sintering and throughout the entire sintering process. The stacking faults are overflowed to the surface during the constant temperature stage. The tilt GBs disappears rapidly at the initial stage of sintering, while the Σ5 GBs is instantly eliminated in the middle temperature region of sintering by the rigid rotation of the nanoparticle sphere. Moreover, besides the contribution of atom diffusion in sintering neck growth, misalignment between the two particles brings about enhanced GBs diffusion. These observations provide insights into the tailored high-angle GBs applicable to nano-scale sphere-plate samples.

The substitution properties of Mn2+ to Zn2+ for Zn3B2O6 ceramic was probed at the atomic scale using the first principle calculation, involving the bond properties, electron density, and formation energy. All samples were synthesized through the solid–state reaction method, and the variation of macro performance, like sintering and dielectric properties, was discussed in detail. The sintering property was characterized by the differential-thermal & thermo-mechanical analyzer and scanning electron microscopy, the dielectric property was characterized by the Network Analyzer, and the phase formation was verified by the X-ray dispersive spectroscopy. Three sites in the Zn3B2O6 crystal are available for Mn2+ to be occupied, and the substitution process for the Zn3 site has the lowest formation energy. The ion-substitution in ZnO4 tetrahedron results in the change of the electron distribution and bond property. The dielectric performance of Zn3B2O6 ceramic has been improved, and the microstructure has been densified at 900 °C, yielding values of er = 6.58, Q×f = 88,100 GHz (15 GHz), relative density = 96.7%, and τf = −56.5 ppm/°C as x = 0.04. Additionally, the activation energy has been decreased and the densification window shifts forward slightly.

Organic-inorganic hybrid formamidinium lead iodide (FAPbI3) perovskite has shown tremendous attention in recently developed photovoltaics and optelectronic devices. However, it suffers from structural instability complications, particularly the spontaneous phase transition from a dark color photoactive perovskite phase (α-FAPbI3) to a yellow color photo-inactive phase (δ-FAPbI3) at room temperature. To stabilize the photoactive α-FAPbI3, several methods were employed, including compositional engineering, 2D layer deposition on the surface, and solvent engineering method. In this communication, we have proposed a facile sequential rapid annealing method to produce the photoactive α-FAPbI3 perovskite on an industrial scale, which is highly stable at room temperature. The structural, morphological, compositional, and optical properties of the perovskite were studied using X-ray diffraction (XRD), UV-visible absorption, Laser Raman, thermogravimetric analysis (TGA), and field emission electron microscopy with elemental analysis (FE-SEM & EDAX). The strong characteristic diffraction peaks of cubic structure in XRD showed the proposed additives free preparation method is more adaptable for the preparation of high quality α-FAPbI3 perovskite for optoelectronic applications. © 2021 The Author(s). Dr. G. Murugadoss acknowledges to the management of Sathyabama Institute of Science and Technology, Chennai, Tamilnadu, India for provided lab facility. We extend their appreciation to the Deputyship for Research & Innovation, “Ministry of Education” in Saudi Arabia for funding this research work through the project no. ( IFKSURG-1440-014 ).

Grain boundary segregation engineering (GBSE) is a promising approach for accurately manipulating chemical composition, structure and properties of grain boundaries (GBs). With the aim of attenuating or even removing disadvantages of GBs in nickel-based superalloys, the GB segregation behaviors of 3d (Ti–Co), 4d (Zr–Rh) and 5d (Hf–Ir) transition-metal (TM) solutes X and their effects on the thermodynamic stability and fracture strength of Ni Σ3 [110](111) symmetrical tilt grain boundary were systematically investigated, using first-principles total-energy calculations based on density functional theory. We found that all TM solutes considered herein can segregate towards the Ni Σ3 [110](111) GB. For TM elements from same row of the periodic table, their segregation energies show a concave-up parabolic-like dependency on the atomic number of TM elements. The GB segregations of all considered solutes can lead to a reduction in GB energy and render the Ni GB more stable, and the GB energies of X-segregated GBs vary linearly with the GB segregation energies of solutes X. Except elements Zr, Hf and Rh, the GB segregations of the other 15 TM alloying elements increase the GB fracture strength. The Mn and Re segregations improve the GB fracture strength and thermodynamic stability to a maximum extent, respectively. The underlying mechanisms for segregation-induced GB stabilizing and strengthening effects were further revealed at the electronic level by analyzing the crystal orbital Hamiltonian populations and deformation charge densities. Our work could provide new insights into designing Ni-based superalloys with desired performances based on the concept of GBSE.

JLC thanks Chinese Scholarship Council and University of St Andrews for financial support. Dendritic silver and copper crystals were produced via Galvanic replacement reactions on zinc and aluminum plates, respectively. The growth orientations of these metals were determined using electron microscopy. The results showed that a fast crystal growth associated with a high concentration of metal cations led to kinetically controlled growth along the axes of the cubic close-packed structures. However, a slow growth rate resulted in thermodynamically controlled growth along the [111] axis. The crystal growth was not found to rely upon the direct deposition of metal cations at crystallographic sites on crystal facets, but instead, hydrated metal cations deposited on the crystal surface to form an amorphous coating layer, followed by the reduction of metal cations and crystallization at the crystal/coating interface. Twin defects and stacking faults were often observed across the whole particle and commonly observed ⅓{422} diffraction spots were explained by stacking faults rather than by the possible presence of any superstructures. The present work offers evidences to claim that both the crystal growth rate and Coulomb interaction between negatively charged crystal surface and metal cations play an important role in the formation of metal dendrites in replacement reactions. Publisher PDF

A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples, due to their typically limited time-stability, and the understanding of the role of external factors that can induce a crystal phase transformation (such as humidity, intense light flux, temperature, etc.). In this perspective, it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant monitoring. In this paper we propose Raman spectroscopy as the ideal technique to solve this problem. The vibrational analysis of CsPbI3 in the α-phase and δ-phase and of the Cs4PbI6 secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT framework. Finally, the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process.

KDP single crystals are widely used in inertial confinement fusion and high power lasers due to the wide transmission band, high laser damage threshold, large nonlinear optical coefficient, etc. However, surface and subsurface damages are easily induced into the KDP crystal components during the machining process due to its high brittleness and distinct anisotropy. These damages will reduce the service accuracy and life of KDP crystal components. It is of great significance to study the brittle-to-ductile transition of KDP crystals to achieve high efficiency and precision machining of crystal components. In this work, a theoretical model of brittle-to-ductile transition load during the nanoindentation and nanoscratch processes of KDP crystals was established based on the energy conservation law and dislocation theory. This model took the anisotropy of KDP crystals into account. Nanoindentation and nanoscratch experiments by using different indenters were performed to verify the theoretical model of brittle-to-ductile transition load. The experimental results of the brittle-to-ductile transition load agreed well with the theoretical results, which indicated that the model was reliable. Both experimental and theoretical results showed that the critical load of brittle-to-ductile transition during the nanoindentation and nanoscratch processes increased as the half cone angle increased. In addition, the critical load of brittle-to-ductile transition load of the scratch was lower than that of the indentation under the same condition. The results also demonstrated that KDP crystals had distinct anisotropy during the nanoindentation and nanoscratch process. Brittle fracture was most likely to occur along [100] orientation during the scratch process. Under the same scratching condition, [110] orientation was prone to achieving ductile machining with high surface quality compared with other orientations.

A series of K2Bi(PO4) (MoO4) samples doped with 0.5%–50% Pr3+ was synthesized by a solid state synthesis method. The crystal phase was monitored by powder X-ray diffraction (XRD) and morphological characteristics were investigated by scanning electron microscopy (SEM). The luminescence properties: photoluminescence excitation and emission spectra, thermal quenching, and fluorescence lifetime values of Pr3+- doped samples were evaluated. The samples showed orange-red luminescence under near-UV excitation. It turned out that the profile of Pr3+ emission spectra is concentration and temperature dependent. Concentration quenching was observed in samples with higher than 1% Pr3+ concentration. Moreover, the calculated color coordinates showed good thermal stability in the 77–500 K temperature range. Based on the obtained results it can be concluded that prepared samples can be used in luminescent security pigments.

A computer-aided methodology for the approximate prediction of axially textured polycrystals’ properties is presented. The input data for the developed application consist of: (a) the two-dimensional diffraction pattern of the material under investigation and (b) the tensors of the elasto-piezo-dielectric properties of the single crystal case. Program ANAELU 2.0 allows the determination of the fiber axis inverse pole figure by means of a Rietveld-type procedure. The Material Properties Open Database (MPOD, http://mpod.cimav.edu.mx) provides free access to the experimentally determined values of the tensor properties for several crystal species. Practical estimates of polycrystals’ properties may be obtained by averaging single crystals’ properties tensors, with the orientation distribution function (the symmetry-axis inverse pole figure, in fiber textures) as a weight factor. This treatment, with the application of the Voigt, Reuss and Hill approaches, requires special precautions when it comes to the coupling properties (e.g. piezoelectricity, magnetostriction, magnetoelectricity). Some key physical, mathematical and computational aspects related to the considered topic are discussed. Program GISELLE systematizes the calculation of polycrystal properties under the considered treatments. The application of the proposed methodology to real-world events is illustrated by means of a case study. Resumen: Se presenta una metodología asistida por computadora para la predicción aproximada de las propiedades de policristales con textura axial. Los datos de entrada para la aplicación desarrollada consisten en: a) el patrón de difracción bidimensional del material bajo investigación y b) los tensores de las propiedades elasto-piezo-dieléctricas para el caso del monocristal. El programa ANAELU 2.0 permite determinar la figura inversa de polos del eje de la fibra mediante un procedimiento de tipo Rietveld. La base de datos de propiedades de los materiales Material Properties Open Database (MPOD, http://mpod.cimav.edu.mx) proporciona acceso gratuito a los valores experimentales de las propiedades tensoriales de numerosas especies monocristalinas. Una metodología de valor práctico para el pronóstico aproximado de las propiedades de policristales texturados consiste en promediar los tensores de las propiedades de los cristales individuales, con la función de distribución de orientaciones (la figura inversa de polos del eje de simetría, en texturas de fibra) como factor de peso. Este tratamiento, con la aplicación de los enfoques de Voigt, Reuss y Hill, requiere de precauciones especiales cuando se trata de las llamadas propiedades de acoplamiento (por ejemplo, piezoelectricidad, magnetostricción, magnetoelectricidad). Se discuten algunos aspectos clave (físicos, matemáticos y computacionales) relacionados con el tema considerado. El programa GISELLE sistematiza el cálculo de las propiedades del policristal bajo los tratamientos considerados. Se muestra la aplicación de la metodología propuesta a un caso ilustrativo.

Ni3Al-based single crystal alloy IC6SX with different crystal orientations were prepared by seed crystal method. The microstructure and heat treatment of the alloy were investigated. The results showed that the microstructure of the alloy was in dendrite structure, and the crystal orientation had significant effect on the dendrite morphology of this alloy. The precipitated phases of (MoNi)6C and NiMo appeared in the microstructure of the three alloys with different crystal orientations during solidification process. Compared with other two alloys, the volume fractions of precipitated phases of both (MoNi)6C and NiMo was the most in the alloy with [111] orientation and the least in the alloy with [001] orientation. The solidus and liquidus temperatures of the alloy IC6SX tested by differential scanning calorimetry (DSC) were 1356 °C and 1387 °C, respectively. Meanwhile, the effect of different solution temperatures on the microstructure of the alloy with different orientations was studied. The results showed that the precipitated phases of (MoNi)6C and NiMo were eliminated with the solid solution treatment under the condition of 1300 °C/10 h. However, the incipient melting of the alloys occurred due to the dissolution of low melting point phases. As the temperature dropped to 1280 °C, the area of incipient melting in the alloy with different orientations decreased gradually. However, there was no incipient melting appearing in the three alloys with different orientations when the solution treatment temperature dropped to 1260 °C.

Herein, we describe the growth and morphology of well-defined dyed crystals of KH2PO4 (potassium dihydrogen orthophosphate; KDP) containing organic azo (sunset yellow; SSY) dye in the {1 0 1} & {0 0 1} pyramidal growth sectors. An understanding on selective dye inclusion in various growth sector of host crystal is proposed, which will help in designing novel tailor-made dyed photonic crystals. The structural analysis and the identification of various functional groups present in as grown KDP crystals were carried out using powder XRD, FTIR and Raman studies. Solid state transmittance spectra for dyed KDP crystals displayed three absorption peaks at 230 nm, 311 nm and 477 nm, which were blue shifted for SSY dye in KDP crystal relative to neutral aqueous solution of SSY dye. These blue shifts in the absorption maxima confirm the successful incorporation of sunset yellow dye into the pyramidal growth sectors of dyed KDP crystals. The band around 409 nm in the photoluminescence emission spectrum indicates a violet emission. SSY dye doped KDP crystals showed enhanced dielectric properties and thermal stability as compared to pure KDP crystal. The mechanical strength of the KDP crystals estimated using Vickers microhardness test was found to decrease with the increase in SSY dye doping.

Conventional SEM-based micro-texture technique has attracted broad interests in recent years. There is also an important need to develop TEM based micro-texture methods, since it was expected to back up some of the shortages of conventional micro-texture technique. In the present work, a new methodology was proposed for measuring the micro-texture in TEM manually without the assistance of any external commercial attachment. The orientation matrix, which maps uniquely to the Euler angles, was considered the transformation matrix between crystal coordinates and the sample coordinate. By tilting the TEM specimen to a low-index zone axis with a double-tilt sample holder, the crystal coordinates could be drawn based on the acquired diffraction pattern. The transformation matrix between each defined coordinates could be deduced; and the Euler angles were identified accordingly. The micro-texture of a twin lamella in a rolled magnesium sheet was analyzed as an example.

TiO2-supported clinoptilolites (TiO2/clinoptilolites) were successfully synthesized with controlled crystal phase and particle size via hydrothermal method to enhance photocatalytic performance of TiO2. The effects of various parameters including temperature, acidity and concentration of Ti-containing solutions on the particle size, crystal phase and agglomeration of TiO2 supported on clinoptilolite were investigated thoroughly by characterizations of X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), BET isotherm, UV–visible (UV–vis) spectrophotometer and Malvern zetasizer. The results demonstrate that increasing temperature and strengthen acidity are beneficial to enhance the crystallinity and particle size of supported TiO2. Increase in acidity also leads to more uniform distribution of TiO2 on the surface of clinoptilolite. The TiO2 nano-crystals deposited on the surface of clinoptilolite, exhibit rutile or anatase phase, strongly depending on the preparation procedure. The resultant TiO2/clinoptilolites could be used as photo-catalysts for the degradation of crystal violet (CV) dye in aqueous solution, showing a higher photo-catalytic activity with 89% degradation within 100 min. The effect of operational parameters, such as pH values of reaction media, dose of used catalyst, and concentration of CV dye on the CV degradation performance were investigated, in which the kinetics of CV dye degradation was found to follow the pseudo-first order kinetic model. Keywords: TiO2, Clinoptilolite, Hydrothermal method, Crystal phase, Degradation, Crystal violet dye

This work aims to study the XRD of 5 Boron oxides crystal with different X-ray sources using Quantum Expresso. When XRD was done with angle vs. intensity, a pretty exciting observation was observed: the single high-intensity peak was observed for each source. The high intensity with large Bragg’s angle is observed with Fe-sources among the considered source (Cu, Ag, Mo, and Fe). This shows lower atomic mass sources have higher Bragg’s angle when incidence on a sample of Boron oxides. The high-intensity peak when Fe-sources is used for XRD of B6O, BO3, B2O, B8O, B2O3 was observed at an angle of 44.3, 37.5, 11, 44.3, 39.8 degrees, respectively.

This study explored the use of X-ray computerized microtomography (micro-CT) and confocal Raman microscopy to provide complementary information to well-established techniques, such as confocal laser scanning microscopy (CLSM), for the microstructural characterization of cheese. To evaluate the potential of these techniques, 5 commercial Cheddar cheese samples, 3 with different ripening times and 2 with different fat contents, were analyzed. Confocal laser scanning microscopy was particularly useful to describe differences in fat and protein distribution, especially between the 2 samples with different fat contents. The quantitative data obtained through image analysis correlated well with the nutritional information provided in the product labels. Conversely, micro-CT was more advantageous for studying the size and spatial distribution of microcrystals present within the cheese matrix. Two types of microcrystals were identified that differed in size, shape, and X-ray attenuation. The smallest, with a diameter of approximately 10 to 20 μm, were more abundant in the samples and presented a more uniform roundish shape and higher X-ray attenuation. Larger and more heterogeneous crystals with diameters reaching 50 μm were also observed in scarcer numbers and showed lower X-ray attenuation. Confocal Raman microscopy was useful not only for identifying the distribution of all these components but also allowed comparing the presence of micronutrients such as carotenoids in the cheeses and provided compositional information on the crystals detected. Small and large crystals were identified as calcium phosphate and calcium lactate, respectively. Overall, using micro-CT, confocal Raman microscopy, and CLSM in combination generated novel and complementary information for the microstructural and nutritional characterization of Cheddar cheese. These techniques can be used to provide valuable knowledge when studying the effect of milk composition, processing, and maturation on the cheese quality attributes.

In this work, we have studied the preparation and properties of an alumino-phosphate glass with composition 13Na2O-13K2O-16BaO-4Al2O3-54P2O5 (mol%). The first part of the work deals with the study of the processing conditions of the dehydroxylation of the phosphate glass, which was performed by remelting under N2 flow using graphite crucibles. Glass samples from 5 to 50 g and Nd2O3 doped were submitted to dehydroxylation and the influence of temperature, time, mass of glass and viscosity were correlated with the content of water in the glasses through the coefficient of absorption of OH ions. The network structure of the glasses was also determined by means of 31P and 27Al 1D/2D nuclear magnetic resonance and the local environment of Nd3+ ions was probed by electron paramagnetic resonance. The optimized conditions of processing were then used to obtain a dehydroxylated glass with a 2.5 wt% Nd2O3 whose spectroscopic and laser emission properties were studied. The spectroscopic properties of Nd3+ ions which include, Judd-Ofelt calculation, stimulated emission cross-section of the laser transition, lifetime, and quantum efficiency are presented. Site-selective laser spectroscopy and stimulated emission obtained under selective wavelength pumping along the 4I9/2→4F5/2 absorption band were performed to determine the distribution of crystal field in which the rare earth is located, together with its influence in the pump wavelength dependence of the spontaneous and laser emissions of Nd3+ in this glass matrix., The authors thank funding from projects from Agencia Estatal de Investigación of Spain (FEDER, UE) MAT2017-87035-C2-1-P/-2-P, MAT2015-65356-C3-1-R, RTI2018-096918-B-C41, PID2020-115419GB-C21/C-22, and the project from the Basque Country Government PIBA1824.

Transparent oxyfluoride glass-ceramics (GCs) containing KLaF4 nanocrystals (NCs) doped with Nd3+were prepared by Spark Plasma Sintering (SPS). Glass powder pellets were sintered under a vacuum atmosphere, optimizing the processing parameters such as particle size, pressure, temperature, and holding time to obtain full densification. Transparency decreased when decreasing the particle size due to higher carbon contamination from the die. The α-KLaF4 crystalline phase was identified by X-ray diffraction (XRD) and its average crystal size was 10–20 nm. High-resolution transmission electron microscopy (HR-TEM) confirmed the presence of KLaF4 nanocrystals with incorporated Nd3+ions. Low-temperature site-selective emission and excitation spectra of Nd3+ions confirmed that α- KLaF4 was the predominant polymorph, although a minor presence of β- KLaF4 was also demonstrated., This work was supported by MINECO under Projects MAT2017–87035-C2–1-P/−2-P (AEI/FEDER, UE), PID2020–115419GB-C-21/C-22 and Basque Country Government PIBA2018–24. AAC also thanks the scholarships of the Federal Agency for the Support and Improvement of Higher Education (CAPES), contract #99999.002598/2015–09. This paper is part of the dissemination activities of project FunGlass. This project has received funding from the European Union´s Horizon 2020 research and innovation program under grant agreement No 739566.

In this paper, Au nanoparticles loaded ZnO nanocones with the dominant { 10 1 ¯ 1 } facet, nanoflakes with the dominant {0001} facet, and nanorods with the dominant { 10 1 ¯ 0 } facet were synthesized and the crystal facet effects of the ZnO on the ethanol-sensing property of the Au/ZnO sensors were investigated. The size of gold nanoparticles and the ethanol-sensing response strongly depended on the facet structures of the ZnO supports. The high surface energy of { 10 1 ¯ 1 } facet led to the strong interaction between the Au nanoparticles and the ZnO nanocones, which was beneficial to the stability of Au nanoparticles and the increase of the catalytic activity of the Au/ZnO nanocones. Temperature-programmed surface reaction results indicated that the high activity of the Au/ZnO nanocones accelerated the ethanol-sensing reaction. The acceleration resulted in the remarkable change of depletion layer and high ethanol-sensing response.

The oxide materials Ca3Co4O9 and Na2Ca2Nb4O13 were combined in a new ceramic composite with promising synergistic thermoelectric properties. Both compounds show a plate-like crystal shape and similar aspect ratios but the matrix material Ca3Co4O9 with lateral sizes of less than 500 nm is about two orders of magnitude smaller. Uniaxial pressing of the mixed compound powders was used to produce porous ceramics after conventional sintering. Reactions between both compounds and their compositions were thoroughly investigated. In comparison to pure Ca3Co4O9, mixing with low amounts of Na2Ca2Nb4O13 proved to be beneficial for the overall thermoelectric properties. A maximum figure-of-merit of zT = 0.32 at 1073 K and therefore an improvement of about 19% was achieved by the ceramic composites.

It is used the Hirshfeld surface (HS) analysis to discuss the strength of the interactions in the cobalt selenate pentahydrate. The HS analysis is required to predict the properties of an ionic crystal. This analysis becomes a valuable tool for the quantitative clarification of the crystal structure and it is necessary for the choice of crystal application. The HS and its fingerprint plots were used. Almost 69.4% of the total HS was related to O⋯H/H⋯O interactions. The calculated enrichment ratios analysis showed that the most favored contacts (expressed by Er value of 2.51) are O⋯Co, followed by Se⋯O (Er = 2.35). It was found that the structure was stabilized by complex (Co⋯(OH2)) and hydrogen bonds (H⋯O–H). The infrared spectra of cobalt selenate pentahydrate are presented and discussed.

The authors report growth, refractive index dispersion, optical absorption and Judd-Ofelt spectroscopic properties of Er3+-doped lutetium gallium garnet (Lu3Ga5O12) single-crystal. The crystal was grown by Czochralski technique. The density of the crystal was measured by Archimedes method. Er3+ concentration in the crystal was measured by inductively coupled plasma atomic emission spectroscopy. The measurement results allow to reach that Er3+ ion in the crystal has a desired segregation coefficient ∼1.0. Refractive index of the crystal was measured as a function of wavelength in the range of 245–1553 nm using an ellipsometer and a prism coupler, and a Sellmeier equation is established for the crystal. Optical absorption of Er3+ in the crystal was studied in the wavelength range of 300–1700 nm and Er3+ absorption cross section spectrum was obtained. Based on the absorption cross section spectrum and the Sellmeier equation, Judd-Ofelt analysis was done for the crystal. Visible, near-infrared and mid-infrared fluorescence spectra and lifetimes of Er3+ in the crystal were measured, and emission characteristics are demonstrated. Spectroscopic knowledge of peaking absorption cross section, oscillator strength, Judd-Ofelt intensity parameters, radiative rate, fluorescence branch ratio, radiative and fluorescence lifetime, and quantum efficiency of some typical Er3+ emissions is obtained.