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Carbonaceous materials are the most attractive choices for rechargeable potassium ion batteries (PIBs), but many K-ion batteries exhibit low specific capacity, limited cycling stability, and disappointed rate capability for the poor K-ions intercalation performance. Here, we chose graphene paper as the research object, fabricated a freestanding K–Cl―graphene paper electrode with abnormal-stoichiometric KxCl crystals (KxCl-rGO), and proposed a novel universal design strategy by using this electrode to achieve a high-efficiency K-graphene battery. Compared with pure rGO, K x Cl-rGO displays a high reversible capacity of 318 mAh g−1 at 20 mA g−1 (38.9% higher than rGO) and can retain a reversible capacity of 157 mAh g−1 at 100 mA g−1 after 500 cycles. The increased K-ion diffusion and enhanced electrical conductivity (the conductivity increased 83% than rGO) play a significant role in improving the potassium storage performance of K x Cl-rGO. What's more, for graphene with more functional groups, this pre-treatment improves the potassium storage performance of carbon materials more significantly (approximately doubled). [Display omitted] [ABSTRACT FROM AUTHOR]

The performance of oil-impregnated paper significantly affects the safety and reliability of transformers. Previous studies on water reducing the breakdown strength of oil-impregnated paper have been mainly due to increasing charge carriers and conductivity. However, the influence of water on the cellulose crystal structure of oil-impregnated paper is still not clear; in particular, its role on breakdown strength remains ambiguous. In this study, the AC breakdown strength and crystal structure of vegetable and mineral oil-impregnated paper with different moisture contents were investigated. The results show that with increasing moisture content, the cellulose crystallinity and crystal size increases linearly, while the breakdown strength decreases. The breakdown strength of vegetable oil-impregnated paper is higher than that of mineral oil-impregnated paper and is less affected by moisture. Herein, a model is proposed on the effects of water on the crystal structure of oil-impregnated paper and the correlation of breakdown strength with crystal structure is reported. [ABSTRACT FROM AUTHOR]

Since the 1940s, it has been known that diffusion in crystalline solids occurs due to lattice defects. The diffusion of defects can have a great impact on the processing and heat treatment of materials as the microstructural changes caused by diffusion can influence the material qualities and properties. It is, therefore, vital to be able to control the diffusion. This implies that we need a deep understanding of the interactions between impurities, matrix atoms, and intrinsic defects. The role of density functional theory (DFT) calculations in solid-state diffusion studies has become considerable. The main parameters to obtain in defect diffusion studies with DFT are formation energies, binding energies, and migration barriers. In particular, the utilization of the nudged elastic band and the dimer methods has improved the accuracy of these parameters. In systematic diffusion studies, the combination of experimentally obtained results and theoretical predictions can reveal information about the atomic diffusion processes. The combination of the theoretical predictions and the experimental results gives a unique opportunity to compare parameters found from the different methods and gain knowledge about atomic migration. In this Perspective paper, we present case studies on defect diffusion in wide bandgap semiconductors. The case studies cover examples from the three diffusion models: free diffusion, trap-limited diffusion, and reaction diffusion. We focus on the role of DFT in these studies combined with results obtained with the experimental techniques secondary ion mass spectrometry and deep-level transient spectroscopy combined with diffusion simulations. [ABSTRACT FROM AUTHOR]

When a cubic lattice is confined by a surface layer, the effective thermoelastic properties can be tailored by the prestress produced by the surface. The thermal expansion coefficient, temperature derivative of elasticity, and the equation of state (EOS) of the solid depend on the potential of each bond and the lattice structure, which can be predicted by the recently developed singum model. This paper first uses a granular lattice confined by a spherical shell to demonstrate singum modeling of the thermoelastic behavior of the cubic lattices and then extends it to atomic crystal lattices by considering the surface tension and long-range interactions. Given the elasticity and the EOS of a cubic crystal, the interatomic potential can be inversely derived. As the bond length changes with thermal expansion and pressure, the singum model predicts the temperature- and pressure-dependent elasticity. Using the orientational average, isotropic elastic constants can be obtained for polycrystals. The case study of copper (Cu) demonstrates the versatility of the model for different cubic lattices and predicts the experimental results of pressure- and temperature-dependent elasticity. The singum model is general for different lattice types and EOS forms and provides clear physical and mechanical meanings to correlate the interatomic potential, EOS, and elasticity in the closed-form formulation, which is very useful in engineering design and analysis of metal structural members in fire, geothermal, and space applications without the needs of large-scale numerical simulations. [ABSTRACT FROM AUTHOR]

A facile route to rapidly assemble presynthesized MOF [NH 2 -MIL-101(Cr)] crystals onto polyimide (PI) fibers at ambient temperature was proposed in this article. Furthermore, PI@PDA@MOF fibers were used to fabricate the paper-based filters for high temperature dust removing by wet-forming process. Prior to this, dopamine was dip-coated onto the surface of inert PI fibers to active the fiber surface. Herein, MOF crystals were chemically induced using β-cyclodextrin (β-CD) and cetyltrimethylammonium bromide (CTAB) as surfactant assembly agents, which quickly self-assembled on the crystal surface and promoted robust chemical surface attachment onto the activated PI@PDA fibers. BET results manifested that the overall surface area of PI@PDA@MOF fibers exceeded 800 m2/g with assistance of "MOF-cloth". Filtration performance experimental results indicated that removal efficiency of composites reached as high as 93.05 ± 1.27% at a lower pressure drop of 57.5 Pa and a higher quality factor of 0.0464 Pa-1 for PM 0.3 under the high temperature of 260 °C. Image 1 [ABSTRACT FROM AUTHOR]

Brillouin light scattering is a versatile measurement technique of the dispersion of bulk acoustic phonons in amorphous and crystalline solids. It allows contactless and non-destructive characterization of the relevant material tensors of optically transparent materials, provided that the optical refraction indices, and in addition the dielectric tensor for piezoelectric materials, are known beforehand. The complete estimation of the anisotropic material tensors is often performed using many different crystal orientations, and hence different samples of the same crystal. In this paper, we consider the problem of measuring those tensors using a single sample of an anisotropic single crystal with trigonal symmetry. A complete measurement requires sufficient experimental diversity in the phonon wavevectors when sampling the phonon velocity surfaces, hence the consideration of a large number of directions away from crystallographic axes. We estimate all six independent elastic constants of non-piezoelectric sapphire ( 3 ¯ m point group) with a single X-cut wafer and the six independent elastic constants together with the four independent piezoelectric constants of piezoelectric lithium niobate (3 m point group) with a single Y-cut wafer. The estimated tensors are in close agreement with those reported in the literature based on resonant ultrasonic techniques. [ABSTRACT FROM AUTHOR]

This paper presents a world-leading scintillation light yield among inorganic crystals measured from a 0.5 kg pure-CsI detector operated at 77 Kelvin. Scintillation photons were detected by two 2-inch Hamamatsu SiPM arrays equipped with cryogenic front-end electronics. Benefiting the light yield enhancement of pure-CsI at low temperatures and the high photon detection efficiency of SiPM, a light yield of 30.1 photoelectrons per keV energy deposit was obtained for X-rays and γ -rays with energies from 5.9 to 59.6 keV. Instrumental and physical effects in the light yield measurement are carefully analyzed. This is the first stable cryogenic operation of kg-scale pure-CsI crystal readout by SiPM arrays at liquid nitrogen temperatures for several days. The world-leading light yield opens a door for the usage of pure-CsI crystal in several fields, particularly in detecting the coherent elastic neutrino-nucleus scattering of reactor neutrinos. The potential of using pure-CsI crystals in neutrino physics is discussed in the paper. [ABSTRACT FROM AUTHOR]

A stable fluorescent nanofibrous membrane was fabricated by in situ growing Eu-MOF crystals on electrospun polyacrylonitrile nanofibers modified with γ-aminobutyric acid. This nanofibrous membrane can be used as a convenient fluorescent test paper for rapid and cyclic detection of nitrobenzene. [ABSTRACT FROM AUTHOR]

Crystalline Na2V6O16·3H2O nanobelts have been synthesized by refluxing V2O5 and NaF and self-weaved into a sheet of paper via a vacuum filtration process. Scanning electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy were used to characterize the morphology, structure, and chemical composition of the nanobelt papers. The dehydrated Na2V6O16 nanobelts are excellent field emission candidates, with a low turn-on field of 6.8 V/μm, a large current density up to 2.5 mA/cm2 at an electric field of 10 V/μm, and a very uniform distribution of emission sites. [ABSTRACT FROM AUTHOR]

In a recent paper Azhar et al., (Mater. Res. Innov. ) claim to have grown a tris (thiourea) potassium barium sulphate (TTPBS) crystal, which according to them is a novel NLO bimetallic crystal. In this comment, we prove that the so called TTPBS is a dubious crystal. In addition, we show that the so called barium thiourea chloride (Raju et al Mater. Res. Innov, 2016) thiourea barium chloride (Mahendra et al Optik 2017) and calcium bis(thiourea) chloride (Anis et al Optik 2016) single crystals are all dubious materials and do not contain any alkaline-earth metal but are simply thiourea. [ABSTRACT FROM AUTHOR]

This paper reports the derivation and implementation of the electric dipole-magnetic dipole and electric dipole-electric quadrupole polarizability tensors at the density functional theory level with periodic boundary conditions (DFT-PBC). These tensors are combined to evaluate the Buckingham/Dunn tensor that describes the optical rotation (OR) in oriented chiral systems. We describe several aspects of the derivation of the equations and present test calculations that verify the correctness of the tensor formulation and their implementation. The results show that the full OR tensor is completely origin invariant as for molecules and that PBC calculations match molecular cluster calculations on 1D chains. A preliminary investigation on the choice of density functional, basis set, and gauge indicates a similar dependence as for molecules: the functional is the primary factor that determines the OR magnitude, followed by the basis set and to a much smaller extent the choice of gauge. However, diffuse functions may be problematic for PBC calculations even if they are necessary for the molecular case. A comparison with experimental data of OR for the tartaric acid crystal shows reasonable agreement given the level of theory employed. The development presented in this paper offers the opportunity to simulate the OR of chiral crystalline materials with general-purpose DFT-PBC methods, which, in turn, may help to understand the role of intermolecular interactions on this sensitive electronic property. [ABSTRACT FROM AUTHOR]

This paper presents a holistic view of the structural phase transitions in nanocrystals. The databases for size-induced phase transitions is a main part of this paper. The database on transitions with temperature contains 603 items on 415 crystals, and database on transitions under high pressure contains 209 items in 124 crystals. Moreover, some new aspects of such transitions are presented like island diagram and new analysis of anomalous compressibility observed in some nanocrystals. [ABSTRACT FROM AUTHOR]

My comments concern the significant error in the crystallographic part of the commented papers. It was discovered that the studied nanocrystals are of sillenite type and the correct formula should be Bi 25 FeO 39 :Co,Ti and Bi 25 FeO 39 :Ni,Ti instead of BiFeO 3. Moreover, the type of unit cell is not correct. Due to the doping the new type of unit cell, previously unknown, was proposed for such crystals. It was found that the studied sample contains two slightly different phases of the sillenite type. The actual chemical composition of the studied crystals is not known. [ABSTRACT FROM AUTHOR]

In this paper, we explore the asymmetry observed between the effects of photon–phonon coupling (nested-dressing) and a crystal field (CF) on the fine structure of fluorescence (FL) and spontaneous four-wave mixing (SFWM) in Eu3+: BiPO4 and Eu3+: NaYF4. The competition between the CF and the strong photon–phonon dressing leads to dynamic splitting in two directions. The CF leads to static splitting in one direction under weak phonon dressing. The evolution from strong dressing to weak dressing results in spectral asymmetry. This spectral asymmetry includes out-of-phase FL and in-phase SFWM. Further, the large ratio between the dressing Rabi frequency and the de-phase rate leads to strong FL and SFWM asymmetry due to photon–phonon constructive dressing. Moreover, the experimental results suggest the analogy of a spectra asymmetry router with a channel equalization ratio of 96.6%. [ABSTRACT FROM AUTHOR]

With the rapid development of silicon-based light detectors with high detection efficiency and long-wavelength sensitivity, the development of near-infrared scintillation crystals has become a hotspot. Especially, the Sm2+ doped europium-based halide crystals exhibit excellent near-infrared luminescence properties. In this paper, Cs4 EuI6: Sm near-infrared scintillation crystals with a size of cm-level were successfully prepared by Bridgman method. The composition and structure were discussed by XRD, XPS and ICP-OES methods, indicating that the Sm2+ was introduced and has no obvious effect on the crystal structure of the matrix. Under ultraviolet and X-ray excitation, the crystal has two luminescence centers (Eu2+ and Sm2+), and the emission peaks are located at 450 and 840 nm, respectively, corresponding to the 5d→4f luminescence of Eu2+ and Sm2+. The decay time of Eu2+ and Sm2+ is at the level of microsecond under ultraviolet excitation. The results show that the emission wavelength gradually varies from blue to near infrared as Sm2+ doping concentration increased. The effects of Sm2+ concentration on the luminescence properties, Eu2+ -Sm2+ energy transfer and decay time of the crystals were also studied, which means that the luminescence properties can be tuned by adjusting the Sm2+ doping concentration. [ABSTRACT FROM AUTHOR]

In recent studies, it has been discovered that phonons can carry angular momentum, leading to a series of investigations into systems with three-fold rotation symmetry. However, for systems with two-fold screw rotational symmetry, such as α-MoO3, there has been no relevant discussion. In this paper, we investigated the pseudoangular momentum of phonons in crystals with two-fold screw rotational symmetry. Taking α-MoO3 as an example, we explain the selection rules in circularly polarized Raman experiments resulting from pseudoangular momentum conservation, providing important guidance for experiments. This study of pseudoangular momentum in α-MoO3 opens up a new degree of freedom for its potential applications, expanding into new application domains. [ABSTRACT FROM AUTHOR]

My comments concern the severe errors in the crystallographic part of the commented paper. The correct formula is proposed to be Bi1-xGdxFeO3 instead of BiFe0.95Gd0.05O3. Thus, the actual composition of the studied crystal is not known. Furthermore, it is evident that the sample contains at least three different phases. The subsequent studies do not present the properties of the title compound. [ABSTRACT FROM AUTHOR]

This paper is a continuation of our Dwork crystals series. Here we exploit the Cartier operation to prove supercongruences for expansion coefficients of rational functions. In the process, it appears that excellent Frobenius lifts are a driving force behind supercongruences. Originally introduced by Dwork, these excellent lifts have occurred rather infrequently in the literature, and only in the context of families of elliptic curves and abelian varieties. In the final sections of this paper, we present a list of examples that occur in the case of families of Calabi–Yau varieties. [ABSTRACT FROM AUTHOR]

In this paper, the transparency requirement, regulated in Article 5 UCTD, is discussed. This provision requires traders to draft terms that are to be incorporated into contracts with consumers in plain and intelligible language. The paper discusses the function of the transparency requirement, the different elements, and the consequences of a breach of the requirement: should the contra proferentem rule be applied, is the term lacking transparency unfair, or could it be argued that such term never was incorporated into the contract to begin with? And does it actually matter? [ABSTRACT FROM AUTHOR]

This year marks the 70th anniversary of the discovery of glass-ceramics. On this occasion, a review paper presenting this material and its progress from discovery to the present day is given. This paper explains what glass-ceramics are and points out the growth of interest in such materials and their commercial success. The process of preparing glass-ceramics is described, while special attention is paid to the role of nucleating agents, and the process of nucleation and growth. Factors that decisively affect the properties of glass-ceramics, such as the crystalline phase, its proportion, the composition of the remaining glass phase, and the microstructure, are listed. Owing to the influence of the mentioned factors, it is possible to prepare different types of glass-ceramics with various crystal phases and morphologies, and consequently different properties suitable for various purposes. The most important systems and types of glass-ceramics are presented, their properties and uses are described and explained. The names of the most important brands of commercial glass-ceramics are also mentioned. In the conclusion, a view of the perspective of this material, glass-ceramic types, and areas of application in which the progress is most certain are provided. [ABSTRACT FROM AUTHOR]

Paper-based electrodes modified with molybdenum disulfide (MoS 2) in the form of bulk crystals or exfoliated nanosheets were developed and used as a biosensing platform for the impedimetric detection of miRNAs (miRNA-155 and miRNA-21) related to early diagnosis of lung cancer. For this purpose, MoS 2 crystals or nanosheets were used for the modification of the working electrode area of paper-based platform for the first time in this study. The proposed assay offers sensitive and selective detection of microRNAs by electrochemical impedance spectroscopy (EIS) technique. The entire assay, both the electrode modification and the miRNA detection being completed in 30 min and a single sample droplet (5 μL) was enough to cover working electrode area which enabled analysis in low sample volumes. The limits of detection (LOD) for miRNA-21 and miRNA-155 were calculated both in buffer and fetal bovine serum media. It is found that the LOD is varying between 1 and 200 ng/mL. In comparison to nanosheets, a larger electroactive surface area was obtained with bulk MoS 2 resulting in lower LOD values on miRNA detection. The paper-based electrodes showed high specificity towards their target sequences. Moreover, they effectively discriminated single base mismatched non-target sequences. The advantages of these MoS 2 paper based electrodes include high sensitivity, and low-cost provide great potential for improved monitoring of miRNA biomarkers even in artificial serum media. [Display omitted] • MoS 2 crystals and MoS 2 nanosheets modified paper-based electrodes were developed. • Impedimetric detection of miRNAs for early diagnosis of lung cancer was performed. • All assay, electrode modification and miRNA detection being completed in 30 min. • The lowest LOD for miRNA-155 in FBS medium was found to be 1 ng/mL by MoS 2 modified electrode. • Biosensor design enabled analysis in low sample volume i.e 5 μL. [ABSTRACT FROM AUTHOR]

Photochromic diarylethene is known to exhibit reversible photoisomerization under irradiation with ultraviolet (UV) and visible light. Besides reversible optical properties upon light irradiation, a variety of discontinuous morphological changes of the crystals are reported in the literature, such as sudden crystal bending, cracking, and photosalient effects, which are caused simply by UV and visible light irradiation. These morphological phenomena with discontinuities are micro-scale changes caused by photoisomerization of molecules at the nanoscale and lead to the realization of important functions for optical devices. However, the theoretical models behind these phenomena are not well understood. In this paper, we construct a mathematical model that can treat diverse phenomena in a unified model by using swallow-tail catastrophe, a higher-order catastrophe than cusp catastrophe, from the seven elementary catastrophes that can describe discontinuities in the phenomena. By introducing hyperbolic operating curves in the model, the intrinsic properties of the photochromic crystals are represented. The induced morphogenesis, such as bending, cracking, and photosalient effects, are systematically classified by the proposed catastrophe model, which even implies the possibility of unexplored operating conditions of the crystals and explains known phenomena. The proposed catastrophe-theory-based modeling provides a foundation for understanding and discovering the versatile morphogenesis in photochromic crystals. Furthermore, the proposed approach provides a basis for understanding and discovering various morphological changes in photochromic crystals and similar systems. [ABSTRACT FROM AUTHOR]

In this paper, novel nonlocal reformulations of the conventional continuum-based models for modeling the thermoelastic behavior of cubic crystals based on a recently developed lattice particle method are presented. Like molecular dynamics simulation, the lattice particle method decomposes the grain domain into discrete material particles that are regularly packed according to the underlying atomic lattice. Nonlocal interactions are introduced between material particles and top-down approaches are used to relate model parameters to the material physical constants. Three equivalency assumptions are used in the top-down approach, namely, energy equivalency for the mechanical model, heat transfer rate equivalency for the thermal model, and thermal strain equivalency for the thermal-mechanical coupling model. Different from coordinates transformation used in the conventional continuum-based models, lattice rotation is adopted in the lattice particle method to equivalently represent the material anisotropy while explicitly capturing the crystallographic orientation. Two most common Bravais cubic lattices are studied, i.e., the body-centered cubic lattice and the face-center cubic lattice. The validity and prediction accuracy of the developed models are established by comparing the predicted displacements and temperature results with solutions of conventional continuum theories using the finite element method. [ABSTRACT FROM AUTHOR]

Abstract: Copper-zinc oxide catalyst powders were successfully impregnated into paper-based composites (catalyst paper) of ceramic and silicon carbide (SiC) fibers, prepared using an established wet papermaking process. The catalyst powders were homogeneously scattered over the fiber-mix networks tailored within the catalyst paper. Samples of catalyst paper were subjected to the methanol steam reforming (MSR) process below 300°C to produce hydrogen gas for fuel cell applications. During this process, the catalyst paper samples exhibited a higher methanol conversion efficiency and lower carbon monoxide concentration than those produced either by a commercial pellet-type Cu/ZnO catalyst or the original powdered Cu/ZnO catalyst. The high heat conductivity of the SiC fibers enhanced the catalytic performance, especially contributing to the suppression of the reverse water gas shift reaction. The heat transfer and the heat distribution inside the catalyst paper were improved by the SiC fibers. The MSR efficiency per catalyst weight was greatly influenced by the addition of pulp fibers, which made the catalyst paper porous. Results indicated that these in-paper void structures are suitable for the MSR reaction. Flexible catalyst paper is a promising, easy-to-handle material for practical MSR applications, due to the controllable heat and pore characteristics involved in the MSR performance. [Copyright &y& Elsevier]

Abstract: Copper–zinc oxide catalyst powders were successfully prepared into paper-like composites, called catalyst paper in this study, using ceramic fibers as the carrier matrix of the catalyst. A papermaking technique with a dual polyelectrolyte retention system was used. Catalyst particles were supported on the ceramic fiber networks tailored in the catalyst paper having various types of pores. Pieces of catalyst paper were subjected to methanol steam reforming (MSR) to produce hydrogen gas for fuel cell applications. They demonstrated a higher performance for methanol conversion and hydrogen production in the MSR reaction than commercial Cu/ZnO catalyst pellets, exhibiting an efficacy equivalent to that of the original catalyst powders. The concentration of carbon monoxide, which acts as a catalytic poison for fuel electrode catalysts, decreased remarkably, without any carbon monoxide reduction system. Moreover, the porous structure of catalyst paper influenced the MSR efficiency. It was assumed that the macropores ca. 20μm in diameter greatly contributed to the MSR performance, rather than the mesopores on the catalyst surfaces. Thus, the porous, flexible and easy-to-handle catalyst paper is a promising material for practical MSR applications. [Copyright &y& Elsevier]

This paper demonstrates a novel Eulerian computational framework for modeling anisotropic elastoplastic deformations of organic crystalline energetic materials (EM) under shocks. While Eulerian formulations are advantageous for handling large deformations, constitutive laws in such formulations have been limited to isotropic elastoplastic models, which may not fully capture the shock response of crystalline EM. The present Eulerian framework for high-strain rates, large deformation material dynamics of EM incorporates anisotropic isochoric elasticity via a hypo-elastic constitutive law and visco-plastic single-crystal models. The calculations are validated against atomistic calculations and experimental data and benchmarked against Lagrangian (finite element) crystal plasticity computations for shock-propagation in a monoclinic organic crystal, octahydro-1,3,5,7-tetranitro-1,3,5,7 tetrazocine (β-HMX). The Cauchy stress components and the resolved shear stresses calculated using the present Eulerian approach are shown to be in good agreement with the Lagrangian computations for different crystal orientations. The Eulerian framework is then used for computations of shock-induced inert void collapse in β-HMX to study the effects of crystal orientations on hotspot formation under different loading intensities. The computations show that the hotspot temperature distributions and the collapse profiles are sensitive to the crystal orientations at lower impact velocities (viz., 500 m/s); when the impact velocity is increased to 1000 m/s, the collapse is predominantly hydrodynamic and the role of anisotropy is modest. The present methodology will be useful to simulate energy localization in shocked porous energetic material microstructures and other situations where large deformations of single and polycrystals govern the thermomechanical response. [ABSTRACT FROM AUTHOR]

In this paper, we introduce optical normalized spherical Heisenberg total ferromagnetic recursional flux of Heisenberg spherical ℍ f s -particle with electromagnetic microscale in Heisenberg spherical space ℍ 2 . Hence, we investigate the properties of spherical Heisenberg normalized electromagnetic microscale by ferromagnetic recursional model. Also, we study optical normalized spherical ferromagnetic Heisenberg recursional density with normalized ferromagnetic microscale for spherical Heisenberg ℍ f s -fiber in spherical Heisenberg space ℍ 2 . Finally, we obtain spherical Heisenberg sonic crystal of spherical Heisenberg ℍ f s -fiber with spherical Heisenberg normalized microscale. [ABSTRACT FROM AUTHOR]

Magnesium whitlockite (Mg-WH) powders were synthesized with remarkable efficiency via the dissolution–precipitation method by employing an environmentally benign precursor, gypsum. Under optimized conditions, each 5.00 g of initial gypsum yielded an impressive amount of 3.00 g (89% yield) of Mg-WH in a single batch. Remarkably, no XRD peaks attributable to impurity phases were observed, indicating the single-phase nature of the sample. FT-IR analysis confirmed the presence of the PO43− and HPO42− groups in the obtained Mg-WH phase. The SEM-EDX results confirmed that Mg-WH crystals with homogeneous Ca, Mg, P, and O distributions were obtained. In previously published research papers, the synthesis of Mg-WH has been consistently described as a highly intricate process due to material formation within a narrow pH and temperature range. Our proposed synthesis method is particularly compelling as it eliminates the need for meticulous monitoring, presenting a notable improvement in the quest for a more convenient and efficient Mg-WH synthesis. The proposed procedure not only emphasizes the effectiveness of the process, but also highlights its potential to meet significant demands, providing a reliable solution for large-scale production needs in various promising applications. [ABSTRACT FROM AUTHOR]

This paper focuses on the generation and transformation of defects associated with subsurface damages (SSDs) in seed crystals during the physical vapor transport (PVT) growth of 4H-SiC crystals. SSDs in the 4H-SiC seed crystal were first revealed and labeled through photo-chemical etching. After 30 min of PVT growth on the 4H-SiC seed crystal, we found that ridge-like substances with a height ranging from 0.2 to 1.5 μm were formed in the region above the SSDs in the 4H-SiC seed crystal. Raman spectra analysis indicated that these ridge-like substances were 4H-SiC under tensile strain. We then continued the PVT growth to obtain a 4H-SiC boule and carried out a wafering process to obtain 4H-SiC single-crystal wafers. For the bottom wafer, above the 4H-SiC seed wafer, the full width at a half maximum (FWHM) of the rocking curves of the region above the SSDs of the seed wafer was higher than that in the other regions, indicating that the SSDs degrade the crystalline quality of 4H-SiC single crystal. The average value of the FWHM of the rocking curves of the top wafer became lower than that of the bottom wafer, indicating that the effect of SSDs gradually recovers. Molten-KOH etching indicated that SSDs in the 4H-SiC seed crystal give rise to the formation of low-angular grain boundaries (LAGBs) that consist of a wall of threading edge dislocations (TEDs) in 4H-SiC single crystals. [ABSTRACT FROM AUTHOR]

The growing pressure on school curricula has meant crystals and the science of crystallography have been cut from or made optional for many educational programs. This omission is a serious disservice to the history and understanding of modern sciences, given that crystallography underpins many of the greatest advancements in science over the past century, is a critical component of many modern research papers and patents, and has 29 Nobel Prizes awarded in the field. This contribution describes a simple activity to target classroom and public engagement with crystallography, using marshmallows or equivalent sweets/candy to represent atoms and cocktail sticks to represent bonds, together with examples of how crystals are studied and how they are useful. Though it has a simple basis, this activity can be extended in numerous ways to reflect the aims of the demonstrator, and a few of these are described. [ABSTRACT FROM AUTHOR]

One of the most important challenges in the pharmaceutical industry is to produce crystals with desired size and shape distributions, to enhance the critical quality attributes of the drug product, such as efficacy, and to improve manufacturability during downstream processing, such as filtration, drying and granulation. The paper provides a framework for effective crystal shape and size tuning, based on a systematic exploration of standard techniques, such as the linear cooling and supersaturation control (SSC), and novel methods based on the systematic combination of several techniques, namely direct nucleation control (DNC), wet milling, SSC and shape modification additives. The crystallization of lovastatin, which is notorious for its challenging needle-shaped crystals, with an extremely high aspect ratio, was used as a case study, and polypropylene glycol (PPG-4000), at different concentrations, was used as an effective shape modifier from small-scale tests studied previously. The proposed techniques were implemented in the case of seeded and unseeded systems. It was demonstrated that the combination of temperature cycling and polymer additive enhances greatly the control over the aspect ratio and crystal size distribution, compared to conventional linear cooling and SSC strategies. The implementation of wet milling at the beginning of the process, or the introduction of seeds, enhances even further the control of the critical quality attributes of the crystalline product. [Display omitted] • Developed and validated a new framework for systematic crystal shape and size tuning. • Standard cooling crystallization with a polymer additive was insufficient to improve the aspect ratio of lovastatin. • Crystal shape successfully modified using additives and Direct Nucleation Control (DNC). • The additive caused inhibition along the longest axis which resulted in an effective control of the aspect ratio. • The lowest aspect ratio was achieved using a combination of seeding, milling, additives and DNC. [ABSTRACT FROM AUTHOR]

Symmetry and non-Hermiticity play pivotal roles in photonic lattices. While symmetries, such as parity-time (P T) symmetry, have attracted ample attention, more intricate crystalline symmetries have been neglected in comparison. Here, we investigate the impact of the 17 wallpaper space groups of two-dimensional crystals on non-Hermitian band structures. We show that the non-trivial space group representations enforce degeneracies at high symmetry points and dictate their dispersion away from these points. In combination with either T or P T , the symmorphic p4 mm symmetry and the non-symmorphic p2mg, p2gg, and p4gm symmetries protect exceptional chains intersecting at the pertinent high symmetry points. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) carbon dioxide (CO2) reduction (CO2R) holds the potential to reduce the costs of solar fuel production by integrating CO2 utilization and light harvesting within one integrated device. However, the CO2R selectivity on the photocathode is limited by the lack of catalytic active sites and competition with the hydrogen evolution reaction. On the other hand, serious parasitic light absorption occurs on the front-side--illuminated photocathode due to the poor light transmittance of CO2R cocatalyst films, resulting in extremely low photocurrent density at the CO2R equilibrium potential. This paper describes the design and fabrication of a photocathode consisting of crystal phase-modulated Ag nanocrystal cocatalysts integrated on illumination-reaction decoupled heterojunction silicon (Si) substrate for the selective and efficient conversion of CO2. Ag nanocrystals containing unconventional hexagonal close-packed phases accelerate the charge transfer process in CO2R reaction, exhibiting excellent catalytic performance. Heterojunction Si substrate decouples light absorption from the CO2R catalyst layer, preventing the parasitic light absorption. The obtained photocathode exhibits a carbon monoxide (CO) Faradaic efficiency (FE) higher than 90% in a wide potential range, with the maximum FE reaching up to 97.4% at --0.2 V vs. reversible hydrogen electrode. At the CO2/CO equilibrium potential, a CO partial photocurrent density of -2.7 mA cm-2 with a CO FE of 96.5% is achieved in 0.1 M KHCO2 electrolyte on this photocathode, surpassing the expensive benchmark Au-based PEC CO2R system. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the theory of energy distribution when divergent light undergoes harmonic conversion in KDP crystals, and based on this theory, we design and construct a precision measuring instrument for the detuning angle of (KDP) Crystals (MIDC). The device can obtain the detuning angle of the crystal by a single measurement with an average measurement error of 72.78 urad. At the same time, it also has the function of scanning the full aperture of the crystals. Using the MIDC, it is possible to quickly measure the KDP crystal at a single point and quickly scan the crystal detuning angle at full aperture. In addition, we conduct a theoretical study on the variation of detuning angle caused by gravity-influencing factors under online conditions, propose an optimization formula for the offline measurement results of detuning angle, and calculate the optimized values of detuning angle for two kinds of crystals under 45° online conditions. We finally study the error source of the MIDC device, analyze the trend of the influence of positioning errors of the crystal and optical elements on the detuning angle measurement results, and provide theoretical support for the error monitoring and correction of MIDC. [ABSTRACT FROM AUTHOR]

Poisson's ratio is the fundamental metric used to discuss the performance of any material when strained elastically. However, the methods of the determination of Poisson's ratio are not yet discussed well. The first purpose of this paper is to introduce the five kinds of typical experimental methods to measure Poisson's ratio of glasses, ceramics, and crystals. The second purpose is to discuss the experimental results on the variation of Poisson's ratio by composition, temperature, and pressure reviewed for various glasses, ceramics, and crystals, which are not yet reviewed. For example, in oxide glasses, the number of bridging oxygen atoms per glass-forming cation provides a straightforward estimation of network crosslinking using Poisson's ratio. In the structural-phase transition of crystals, Poisson's ratio shows remarkable temperature-dependence in the vicinity of a phase-transition temperature. The mechanism of these variations is discussed from physical and chemical points of view. The first-principles calculation of Poisson's ratio in the newly hypothesized compounds is also described, and its pressure-induced ductile–brittle transition is discussed. [ABSTRACT FROM AUTHOR]

Zigzag strip bundles are combinatorial models realizing the crystals B (∞) and the highest weight crystals B (λ) over quantum affine algebras U q (g) , and they are closely related with Nakajima monomials and Kashiwara embeddings of specific type. In this paper, we introduce new zigzag strip bundles for U q (g) , which we call reverse zigzag strip bundles in order to distinguish from the previous ones, and we give explicit 1-1 correspondences with the set of Nakajima monomials and the image of Kashiwara embedding which are different from those appeared in the study of the zigzag strip bundles. Another main result is to give different points of view about zigzag strip bundles and reverse zigzag strip bundles. Indeed, the previous 1-1 correspondences between the sets of zigzag strip bundles or reverse zigzag strip bundles, and the sets of Nakajima monomials or images of Kashiwara embeddings were determined based on the number of blocks in the columns of these strip bundles. In our work, we use the number of blocks in the rows of zigzag strip bundles and reverse zigzag strip bundles to provide characterizations of Nakajima monomials and images of Kashiwara embeddings that differ from the previous ones. That is, we give characterizations of Nakajima monomials and Kashiwara embeddings of 4 types. Further, we discuss the connection between zigzag strip bundles and reverse zigzag strip bundles. [ABSTRACT FROM AUTHOR]

In this paper, we present a second-order accurate and linear numerical scheme for the phase field crystal equation and prove its convergence in the discrete L\infty sense. The key ingredient of the error analysis is to justify the boundedness of the numerical solution, so that the nonlinear term, treated explicitly in the scheme, can be bounded appropriately. Benefiting from the existence of the sixth-order dissipation term in the model, we first estimate the discrete H2 norm of the numerical error. The error estimate in the supremum norm is then obtained by the Sobolev embedding, so that the uniform bound of the numerical solution is available. We also show the mass conservation and the energy stability in the discrete setting. The proposed scheme is linear with constant coefficients so that it can be solved efficiently via some fast algorithms. Numerical experiments are conducted to verify the theoretical results, and long-time simulations in two- and three-dimensional spaces demonstrate the satisfactory and high effectiveness of the proposed numerical scheme. [ABSTRACT FROM AUTHOR]

Spontaneous ordering in a system of excited emitters with a powerful short radiation pulse predicted by Dicke attracted the great attention of scientists for decades as a bright example of the nontrivial behavior of a nonequilibrium system. The Bogolyubov reduced description method has some advantages and provides new possibilities in the theoretical investigation of the Dicke process. The paper presents the authors' results of modeling such processes concerning both optical ones in the presence of crystal lattice influence and acoustic superradiance, which is possible in solids. The right choice of reduced description parameters allows the account of atom motions (phonons), cavity influence, and excitations in the emitter system (excitons) in the electromagnetic radiation process. The mathematical analogy between the Dicke system and a spin system in a magnetic field opens the way to applying the reduced description technique to acoustic phenomena previously investigated with the boson variable elimination method. Such a new approach to superradiance in crystals with paramagnetic impurities and with competing mechanisms of relaxation (Wagner model) is outlined. Acoustic superradiance is discussed in connection with the problem of structural phase transitions. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of a new nonlinear crystal Ba2Ga8GeS16. The paper presents a theoretical study of the tuning characteristics of an optical parametric oscillator based on the specified crystal. It has been established that phase matching in this crystal is possible only for the oo-e type of interaction at the selected pump radiation wavelengths. The tuning range extends up to the long-wavelength limit of the crystal transparency. To achieve such a wide tuning range, the crystal must be rotated by 19.7 ∘ using a laser with a wavelength of 1.064 μ m as a pump source and by 0.83 ∘ using a pump wavelength of 1.5 μ m . In addition, the laser-induced damage threshold of the Ba2Ga8GeS16 crystal was studied using the R-on-1 method. The surface damage threshold of this new material is 7 ± 0.5 J/cm2, indicating its high resistance to radiation damage. The obtained laser-induced damage threshold value is an important guideline for the correct and safe usage of the new crystal in high-pulse energy laser systems and nonlinear optical applications. High laser-induced damage threshold in combination with high nonlinearity and a range of transparency makes Ba2Ga8GeS16 a promising material for various applications, including medical laser surgery, where the high laser-induced damage threshold of nonlinear materials is of decisive importance. [ABSTRACT FROM AUTHOR]

The crystal basis of an irreducible highest weight module of type A is realized by a combinatorial model called K-hives. In this paper, we give the tensor product decomposition map of crystal bases of irreducible highest weight modules of type A in terms of K-hives. In the process of constructing the decomposition map, we provide a combinatorial description on K-hives of the decomposition map. [ABSTRACT FROM AUTHOR]

In this paper, two temporal discrete numerical schemes of the modified phase field crystal equation are presented by introducing a Lagrange multiplier U and two auxiliary functions ψ , W , which reduce the order of the original equation in time and space. For these schemes, we prove their mass conservation and energy stability. Error estimates of the BDF2 scheme are given. In the end, some numerical experiments are used to verify the correctness of our theoretical results. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) has received extensive research and attention due to its excellent piezoelectric, electromechanical, and other properties. In particular, tetragonal relaxor ferroelectric single crystals have shown greater application potential in high‐temperature devices due to their higher Curie temperature and better stability. However, the low piezoelectric performance of tetragonal crystals also greatly limits its application, and research on its optical properties is not sufficient. In this paper, the tetragonal phase Sm–PIN–PMN–PT single crystal was obtained by the Bridgman method, and its piezoelectric and electro‐optical properties are studied. At the same time, we gave a complete set of piezoelectric, dielectric, and elastic coefficient matrices. The results show that the crystal has excellent piezoelectric and electromechanical properties. The piezoelectric coefficient can reach 905pC/N, the electromechanical coupling coefficient k33 is 85%, and the kt is 72%. The transmittance of the sample polarized along [001] direction can reach 66%. The effective electro‐optical coefficient γc is 60 pm/V at room temperature and can reach 86 pm/V at 70°C. It has a wide operating temperature range and stable performance with frequency variation, which has certain reference significance for application in new electro‐optical devices. [ABSTRACT FROM AUTHOR]

My comments concern the sever error in the crystallographic part of the commented paper. It was found that the studied crystal is of the sillenite type and the correct formula should be Bi 25 FeO 39 :Cd,Ti instead of some kind of solid solution based on BiFeO 3. Moreover, the type of unit cell is not correct. Due to the double doping the new type of unit cell, previously unknown, was proposed for such crystals. The actual chemical composition of the studied crystals is not known. [ABSTRACT FROM AUTHOR]

My comments concern the significant error in the crystallographic part of the commented paper. It was discovered that the studied crystals are of sillenite type and the correct formula should be Bi 25 FeO 39 :Ni,Ti instead of BiFeO 3. Moreover, the type of unit cell is not correct. Due to the doping the new type of unit cell, previously unknown, was proposed for such crystals. It was found that the studied sample contains two slightly different phases of the sillenite type. The actual chemical composition of the studied crystals is not known. [ABSTRACT FROM AUTHOR]

The article presents several rules for restructuring papers to avoid losing readers. Authors are instructed to focus their papers on a central contribution and to concentrate on the context-content-conclusion (C-C-C) scheme. They are also advised to optimize a paper's logical flow by avoiding zig-zag and using parallelism and to include complete story in the abstract.

We argue that the IR and Ramanspectra of “Lalanine alaninium nitrate” given in “Investigation on the growth, optical behaviour and factor group of an NLO crystal: LAlanine Alaninium nitrate” by Aravindan et al., Cryst. Res. Technol. 42, 1097 2007, actually concern LAlanine. Correspondingly, the data presented in “A comparative study on the growth and characterization of nonlinear optical amino acid crystals: LAlanine LA and Lalanine alaninium nitrate LAAN” by Aravindan et al., Spectrochim. Acta A 71, 297 2008, seems to be erroneous, as is “Synthesis, Growth, and Characterization of a New Semiorganic Nonlinear Optical Crystal: LAlanine Sodium Nitrate LASN”, Sethuraman, et al., Cryst. Growth Des. 8, 1863 2008. In these papers properties and data were reported for LAlanine compounds that actually are LAlanine crystals and, in addition, unit cell parameters were given that seem to have been copied from other papers. © 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]