Effects of thermal demagnetisation on the magnetic properties and hydrogen decrepitation of Sm2TM17 sintered magnets

Honeycomb composites are extensively utilized in critical applications where weight is a concern in a structure, due to their high efficiency in stiffness-to-weight ratio. In this study, the effective elastic orthotropic behavior of honeycomb composites is analytically expressed as a function of the elastic properties of the constituent sheet material and the geometric parameters of the representative unit cell. Closed-form expressions based on classical beam theory and plate theory are evaluated and systematically validated against a high-fidelity finite element analysis FE-based homogenization benchmark constructed from a representative unit cell with in-plane periodic kinematic constraints. The analytical predictions exhibit generally good agreement with the FE results, with plate-theory-based formulations capturing most elastic constants with higher accuracy. To further support the fidelity of the numerical benchmark, the predicted normalized in-plane moduli are additionally compared with published experimental measurements for aluminum honeycombs, demonstrating close agreement for representative specimens. To quantify the influence of the geometric parameters, a Taguchi-style design-of-experiments (DOE) study reveals that relative density and internal cell angle jointly govern the majority of elastic moduli and Poisson’s ratios, while cell height plays a minor role. Furthermore, dedicated parametric studies confirm the cubic thickness-scaling of in-plane moduli (E1, E2, G12), demonstrating the dominant role of bending-controlled deformation. Together, these results establish a validated, high-fidelity FE homogenization benchmark for assessing analytical formulations and providing design-level constitutive data for optimizing honeycomb core sandwich structures.

Beryllium (Be), a critical strategic metal element, is predominantly extracted from beryl, which serves as a key mineral combining significant strategic importance with essential industrial applications. Significant debate remains, however, regarding the mineralogical characteristics and color-causing mechanisms of beryl. In this study, we integrate Electron Probe Microanalysis (EPMA), Fourier transform infrared spectrometer (FTIR), laser Raman spectrometer (LRS), X-ray diffractometer (XRD), and ultraviolet–visible spectrophotometer (UV-VIS) to elucidate the mineralogy and spectral characteristics of pegmatitic beryl from Xinjiang, Northwest China. The results indicate that the beryl mainly presents a yellowish-green color, associated with minerals such as feldspar, quartz, and garnet. The EPMA results confirm the chemical composition of the typical beryl and indicate that the Al content is lower than the theoretical value, reflecting the substitution of Al3+. The FTIR shows characteristic vibrations of Si-O tetrahedral groups within the range of 1400~400 cm−1, along with distinct bending and stretching vibration peaks of H2O molecules observed in the range of 1700~1500 cm−1 and 3500~3800 cm−1, respectively. Combined with spectral analysis, it can be determined that both Type I water and Type II H2O are present in the samples. Raman spectroscopy reveals that the two distinct peaks of beryl are located at approximately 685 cm−1 (attributed to the stretching vibration of Be-O) and 1067 cm−1 (corresponding to the bending vibration of Si-O), respectively. The XRD analysis shows that the ratio of unit cell parameters c/a of the samples ranges from 0.9950 to 1.0068, and the isomorphous substitution in its structure is mainly manifested as the replacement of octahedral coordination sites by Al3+. The UV-VIS shows that Fe3+ exhibits a broad absorption band in the range of 200~300 nm, while no obvious absorption peaks are observed in the range of 300~800 nm. The above characteristics indicate that Fe3+ has a significant impact on the color of beryl. For green beryl samples, a portion of Fe3+ occupies the structural channel sites and interacts with H2O molecules within the channels, which contributes to the yellowish hue of beryl. Our study highlights crucial data for mineralogical identification, genetic tracing, as well as efficient utilization of beryl resources.

An emerging cubic substrate material (Nd,Sr)(Al,Ta)O3 (NSAT) has been analysed using powder and single-crystal X-ray diffraction, transmission electron microscopy, infrared (IR) and ultraviolet-visible range ellipsometry as well as IR- and Raman spectroscopies. Based on this experimental characterization, the structure and vibrational properties are described with improved understanding. On a large length scale the NSAT substrate is found to have a basic simple cubic perovskite structure (a = 3.8427 Å) that, on a small length scale, is subdivided into superstructure ordered nanoscale domains with doubled lattice (unit-cell) parameter (a = 7.6855 Å). Ellipsometry and vibrational spectroscopy show absorption bands consistent with the expected structure type, however, the peak widths indicate significant local deviations from the perfectly ordered superstructure or ideal solid solution. Since the lattice parameter is unaffected, the observed inhomogeneity is not expected to affect the use of NSAT as a substrate for most applications.

Powellite (CaMoO4) is a secondary phase frequently detected in nuclear waste glass corrosion experiments. The coupled substitution in powellite of Ca by a trivalent lanthanide, used as a surrogate for trivalent actinides, and Na+ through Ca1-xNa0.5xLn0.5xMoO4 solid solution formation was investigated. Results suggest homogeneous and complete (0 < x < 1) solid solution formation for Ln = La, Eu, and Yb. X-ray diffraction provides evidence of a progressive evolution of unit cell parameters with the mean ionic radius of cations substituting for Ca and a slight excess molar volume for the La- and Yb-based solid solutions. X-ray absorption spectroscopy revealed that interatomic distances depend on the size of atoms involved in bonding, independent of the extent of Ca substitution, and in some cases on the geometrical arrangement of connected polyhedra. A topological analysis suggests that the observed excess molar volume may originate from local structural disorder due to the difference in size between substituting and substituted dodecahedral cations. Outcomes collectively suggest that the formation of powellite as a glass corrosion product may represent a sink capable of efficiently immobilizing trivalent actinides.

A novel oxonitridosilicate, Li2La8Si6N12O7 was successfully synthesized at 1200 °C using Li3N as a flux. The crystal structure was determined through single-crystal and synchrotron powder X-ray diffraction. Li2La8Si6N12O7 crystallizes in orthorhombic space group Pcca (no. 54) with unit-cell parameters a = 15.5319(1) Å, b = 7.7382(1) Å, c = 15.5019(1) Å, and Z = 4. The structure features a layered framework built from vertex-sharing Si[N/O]4 tetrahedra, with Li[N/O]6 octahedra connecting and stabilizing both the interlayer and intralayer linkages. The octahedral coordination of Li+ was confirmed by solid-state 7Li NMR spectroscopy. Notably, the incorporation of Pr3+ and Tb3+ into the Li2La8Si6N12O7 host yields narrow-band red emission at 630 nm and green emission at 545 nm. This combination facilitates the fabrication of 365 nm near-ultraviolet light-emitting diode (UV LED) chip-based WLEDs with superior color rendering performance.

Bergbauerite, (H 2 O) 2 Mn 2+ 2 (Fe 2 Ti)(PO 4 ) 4 [(OH) 2 [(H 2 O) 10 ]4H 2 O, is a new orthorhombic member of the paulkerrite group, from the Hhnerkobel pegmatite, Bavaria, Germany.It occurs in solution cavities in altered zwieselite, in association with fluorapatite, leucophosphite, jahnsite-(CaMnFe), whiteite-(CaMnFe), phosphosiderite, ferrostrunzite, manganese oxides and other members of the paulkerrite mineral group.Bergbauerite forms isolated and intergrown colourless rhombic tablets, up to 150 m.The tablets are flattened on {010} and show the forms {010}, {111} and {11-1}.The calculated density is 2.38 g cm -3 .Optically, bergbauerite crystals are biaxial (+) with = 1.635(3), = 1.645(3), = 1.657(3) (white light) and 2V (calc.)= 85.4.The empirical formula in structural form is A [K 0.23 (H 2 O) 1.77 ] 2.00 M1 (Mn 2+ 0.96 Mg 0.24 Fe 3+ 0.82 ) 2.02 M2+M3 (Fe 3+ 1.60 Ti 4+ 1.43 ) 3.03 (PO 4 ) 3.95 X [(OH) 1.07 O 0.93 ] 2.00 [(H 2 O) 9.18 (OH) 0.82 ] 3.91H 2 O. Bergbauerite has orthorhombic symmetry with space group Pbca and unit-cell parameters a = 10.547(2),b = 20.406(4),c = 12.478(2), V = 2684.5(8) 3 and Z = 4.The crystal structure was refined using synchrotron singlecrystal data to R obs = 0.058 for 2560 reflections with I > 3(I).A proposal to modify the nomenclature for the paulkerrite group minerals to allow new root names to be applied to group members that have different dominant species at the A and M sites has been approved.

This study investigates the frequency response characteristics of Y-shaped fractal frequency selective fabrics (YF-FSFs) and systematically analyzes the effects of electromagnetic wave polarization, incident angle, unit-cell parameters, and cylindrical bending. Planar YF-FSF samples with different unit spacings and conductive unit sizes were designed and fabricated, and curved samples were obtained by bonding the planar fabrics onto cylindrical molds with various radii. The electromagnetic transmission performance was experimentally evaluated in a microwave anechoic chamber over the 3–14 GHz frequency range. The results indicate that both patch-type and aperture-type YF-FSFs exhibit distinct first- and second-order resonance behaviors and maintain stable frequency response characteristics under different polarization modes and incident angles. Increasing unit spacing or conductive unit size shifts the resonant frequencies toward lower values and alters the resonance strength. Cylindrical bending significantly affects the frequency response characteristics, with circumferential bending having a stronger influence than axial bending, especially on second-order resonances. These findings provide valuable guidance for the structural design and practical application of fractal frequency selective fabrics.

The crystal structure of poly(α-methylene-δ-valerolactone), P(MVL)ROP, synthesized by chemoselective ring-opening polymerization of α-methylene-δ-valerolactone, was determined through a combination of X-ray diffraction analysis and density functional theory (DFT) calculation. The results reveal a triclinic crystal system (space group P1̅) with unit cell parameters: a = 7.26 Å, b = 6.86 Å, c = 7.39 Å, α = 122.09°, β = 89.14°, and γ = 104.88°. The P(MVL)ROP chain adopts an all-trans conformation, as validated by DFT optimization and infrared spectroscopy analysis. Unlike conventional polyesters, P(MVL)ROP, featured with unsaturated bonds on the side chain, exhibits a distinctive triclinic unit cell, with two antiparallel chains included. Independent Gradient Model based on Hirshfeld partition (IGMH) analysis revealed that a series of distinct C–H···O═C interactions between adjacent parallel or antiparallel chains are the key stabilizing forces for the interchain packing.

With the meteoric rise in interest in GLP-1 and GIP analogue peptides in recent years, there is a drive for the use of alternative purification techniques to alleviate processing bottlenecks and reduce the cost of peptide manufacturing. However, a lack of reported crystal structures for this class of peptides has hindered molecular-scale understanding of GLP-1/GIP analogue peptide crystallization, particularly related to acylated peptides. This paper therefore reports what is believed to be the first crystal structure of a GLP-1 and GIP analogue lipopeptide. Crystals obtained using a microseed matrix-screening protocol diffracted to ≤1.6 Å resolution in space group P43, with unit-cell parameters a=b = 64.66, c = 11.42 Å. Model building and the resultant structural analysis reveals that the predominantly helical peptide forms a uniquely porous spiral crystal structure composed of clockwise-ascending monomers in a square pattern, with aromatic C...H-π interactions around Phe22 forming the primary crystal contact between neighbouring square motifs.

Protein crystals are intrinsically hydrated systems, and their structural integrity is strongly influenced by environmental humidity. Understanding the effects of relative humidity (RH) variation on crystal stability is therefore essential for both fundamental research and applied studies. In this work, the structural response of tetragonal hen egg-white lysozyme (HEWL) to controlled RH variation was investigated using in situ X-ray powder diffraction (XRPD). Polycrystalline HEWL samples were subjected to systematic gradual dehydration and rehydration cycles, as well as to non-gradual RH variation protocols. Pawley analysis of the XRPD data enabled monitoring of the evolution of unit cell parameters and unit cell volume as a function of RH. Under all experimental conditions, the tetragonal polymorph (space group P43212; a = 79.105 (4) Å, c = 38.231 (2) Å) was preserved. RH variation induced smooth, continuous and anisotropic lattice changes, characterized by a decrease in the a (=b)-axis and a concomitant increase in the c-axis upon dehydration, while rehydration resulted in the opposite behavior. The overall magnitude of lattice variation remained limited (within ±2%), indicating a high degree of structural stability. Partial degradation of crystallinity was observed only after prolonged exposure to low RH levels. These findings demonstrate the remarkable structural resilience of tetragonal HEWL and highlight the effectiveness of in situ XRPD as a powerful tool for probing hydration-driven lattice responses in protein crystals under realistic environmental conditions.

Zero-valent iron (Fe(0)) nanoparticles have a wide range of applications, including catalysis, energy storage, and even reported roles in human neurochemistry. This study demonstrated that [Fe3(CO)12] dissolves in N,N-Dimethylformamide (DMF) within a minute to resolve the dissolution problem of this complex. Dodecylamine (DDA) was used to produce DDA-coated Fe(0) at 383 K in 30 s with a microwave reactor. The powder X-ray diffraction (PXRD) of the Fe(0) profile indicated a pure-phase face-centred cubic (FCC) structure with Fm3¯m space group. Varying the synthesis time from 30 s to 5 min did not significantly affect the unit cell parameters (3.5276 (±0.0001) and 3.5391 (±0.0001) Å). Microwave use yielded well-dispersed, pure Fe(0) nanoparticles, and the particle size, shape, elemental analysis, and surface oxidation of the Fe(0) nanoparticles were studied using scanning electron microscopy and dispersive X-ray spectroscopy (SEM/EDX). Annular Dark-Field Scanning Transmission Electron Microscopy (ADF-STEM) and Fourier-transform infrared (FT-IR) spectroscopy confirmed the surface coating of Fe(0) nanoparticles with DDA. Thermogravimetric analysis (TGA) was used to demonstrate the surface adsorption of DDA on Fe(0) nanoparticles. In addition, STEM showed that the average nanoparticle size under the stated synthesis conditions was 25.7 nm. This comparatively straightforward procedure offers advantages over existing practical approaches to the synthesis of Fe(0) nanoparticles, including safety, speed and reaction control.

Single crystals of new orthophosphates AMg 2 Fe(PO 4 ) 3 (A = Sr or Ba) have been synthesized by solid-state reaction. From single crystal X-ray diffraction data, their corresponding crystal structures were solved in the orthorhombic system, with the Imma space group and unit cell parameters a = 10.3998 (2) Å, b = 13.2000 (2) Å, c = 6.5364 (1) Å for the strontium compound and a = 10.4996 (2) Å, b = 13.2696 (1) Å, c = 6.6330 (2) Å for the barium compound. Both phosphates crystallize with the α-CrPO 4 structure type. The crystal structure of both orthophosphates is composed of MgO 6 octahedra, FeO 6 octahedra, and PO 4 tetrahedra. The sharing of vertices between those polyhedra leads to a three-dimensional network defining hexagonal tunnels that are occupied by Sr 2+ or Ba 2+ cations.

Abstract Lightweight structures with efficient vibration and noise attenuation capabilities are of great significance for modern engineering applications. Recent advancements have significantly expanded the working frequency range of topological phononic crystal plates. Nevertheless, the design of topological microstructures that enable larger areas for wave transport remains a critical challenge. This study proposes a lightweight hexagonal lattice elastic metamaterial that enables topologically protected transport of low-frequency elastic waves while maintaining structural efficiency. By tuning the geometric parameters of the composite unit cell, a double Dirac degeneracy is formed at the Γ point of the Brillouin zone, leading to a controllable topological phase transition. The band inversion between p - and d -state modes is achieved by breaking the spatial symmetry of the system, resulting in the opening of a nontrivial bandgap. A supercell composed of topologically trivial and nontrivial domains is further constructed to reveal the robust interface state in the bandgap. Further, a finite-sized metamaterial specimen was fabricated, and vibration transmission tests were also conducted to validate the numerical model. The experimental results confirm the existence of low-loss, unidirectional elastic wave propagation along the designed interface, in excellent agreement with the simulated field distributions. This study provides a new strategy for realizing lightweight and low-frequency broadband vibration isolation, while also offering a promising pathway for efficient energy harvesting.

Waste to wealth: transforming Eu2+/Eu3+ co-activation from weak link to strength for advanced multifunctional lighting.

Zeolitic imidazolate frameworks (ZIFs) are three-dimensional (3D) porous materials with only a few exceptions - ZIF-L, Zn2(benzimidazole)4, etc. Herein, we report the synthesis of a new layered ZIF, which we call ZIF-S. We use a surfactant (sodium dodecyl sulfate) as a structure-directing agent, analogous to the concept used in the synthesis of zeolites. The layers contain individual ZIF sheets intercalated by surfactants. Its ordered structure belongs to the tetragonal lattice with the P4̅21m space group. The unit cell parameters are a = b = 16.82 Å; c = 24.5 Å at room temperature. The layered material undergoes topotactic condensation and forms its parent material (ZIF-8 or ZIF-67, depending on the metal node) upon heating to or above 200 °C. ZIF-S layers could be obtained with a large lateral size and a high aspect ratio, which is ideal for the scalable preparation of gas-selective membranes, thanks to the presence of pore apertures suitable for the separation of small gas molecules. Fabrication of gas-selective membranes from a simple coating of ZIF-S is demonstrated.

Abstract A mantle cloak with a novel unit cell design is proposed for the scattering suppression of cylindrical metasurfaces. The proposed cloak is designed for an electrically small cylindrical object. The Mie Theory is employed to calculate the surface impedance of the mantle cloak, which plays a critical role in determining the optimal design parameters. The unit cell parameters necessary for the design are obtained by analyzing the surface impedance. Bistatic Radar Cross-Section (RCS) analyses have been conducted for the cloaked and uncloaked cases of cylinders. The designed cylinder demonstrated remarkable scattering suppression at the operating frequency. Furthermore, the results obtained from the novel unit cell design are compared with findings in the literature, underscoring the improved cloaking performance achieved with the new design. As a demonstration, a single-layer novel unit cell cloaked cylinder is constructed with a total radius equal to 13 percent of the free-space wavelength, a total length corresponding to 1.94 times the free-space wavelength, and a dielectric spacer thickness of 1.27 percent of the free-space wavelength. This single-layer novel unit cell mantle cloak achieves a 16.65 dB total RCS reduction at 3.1 GHz, with a notable decrease in scattering at the operational frequency in all directions.

The interaction of molybdenum with amorphous boron at an atomic ratio of 1 : 2 in a hydrogen atmosphere for 15–30 h at 750°C in an ionic melt of composition 50 mol % NaCl : 50 mol % KCl leads to the formation of a mixture of nanocrystalline α-MoB and Mo2B5 phases with crystallite sizes of approximately 38 and 32 nm, respectively. The α-MoB phase crystallizes in the tetragonal crystal system with unit cell parameters a = 0.311 nm and c = 1.695 nm, whereas the Mo2B5 phase crystallizes in the rhombohedral crystal system with unit cell parameters a = 0.301 nm and c = 2.093–2.094 nm.

Hubbardite (IMA 2025-041), Mg(H 2 O) 6 [(UO 2 ) 2 O(OH)(SO 4 )] 2 8H 2 O, is a new zippeite-like mineral from the Hubbard Homestead mine, Mesa County, Colorado, USA.The new mineral occurs on sandstone matrix in close association with gypsum and an unknown Al-bearing uranyl-oxide hydroxy-hydrate.Hubbardite is orthorhombic, space group Fddd (#70), with unit cell parameters a = 8.8698( 17), b = 34.183(7),c = 39.377(9), V = 11939(4) 3 and Z = 16.Crystals are plates up to about 0.3 mm in diameter, commonly forming subparallel or divergent aggregates.Crystals are flattened on {001} and exhibit the forms {100}, {001} and {140}.Hubbardite is yellow in color but sometimes appears dark brown, especially on edges.It has a pale-yellow streak and is nonfluorescent.It is transparent with vitreous luster.The mineral is flexible, but not elastic, and has a curved and stepped fracture.The Mohs hardness is about 2.The measured density is 3.59(5) g/cm 3 .The mineral is optically biaxial (-), with = 1.570(5), = 1.625( 5), = 1.646(5) (white light).The mea-and the pleochroism is X light yellow, Y yellow, Z brownish yellow; X < Y < Z.The empirical formula is {(Mg 0.92 0.08 ) 1.00 (H 2 O) 6 [(NH 4 ) 0.69 (H 2 O) 7.31 ] 8.00 } {(U 0.98 O 2 ) 2 [O 1.02 (OH) 0.98 ] 2.00 (SO 4 )]} 2 based on O + N = 34 and S = 2 apfu.The crystal structure of hubbardite (R 1 = 0.0616 for 1348 reflections with I > 2 I ) contains zippeite-type sheets between which are Mg(H 2 O) 6 octahedra and isolated H 2 O groups.

Szilagyiite (IMA 2024-063), NaCa 3 (UO 2 )(CO 3 ) 3 (SeO 3 )F(H 2 O) 6 , is a new uranyl-carbonate-selenite mineral from the Pickett Corral mine, Montrose County, Colorado, USA.The new mineral occurs on sandstone and asphaltite matrix in close association with ferroselite, andersonite, schrckingerite, magselite, and an unidentified Na-Ca-uranyl carbonate--selenite-sulfate.Szilagyiite is trigonal, space group R3c (#161), with unit cell parameters a = 9.6542(9), c = 33.465(5), V = 2701.2(6) 3 and Z = 6.Crystals occur as dense yellow-green rosettes up to 1 mm wide and individual tablets up to ~200 m.Szilagyiite crystals are predominantly tabular on {001} and exhibit {001}, {00-1}, {102}, and {0-1-2} forms, with frequent twinning by inversion and perfect {001} cleavage.It has a pale yellow-green streak and fluoresces dimly green under longwave UV and 405 nm illumination, but has no apparent fluorescence under SWUV.Crystals are transparent with vitreous luster and exhibit a brittle, uneven fracture, with a Mohs hardness between 2-3.The calculated density based on the empirical formula is 3.17 g/cm 3 , and 3.16(2) g/cm 3 as measured by flotation in a mixture of diiodomethane and toluene.The mineral is optically uniaxial (-), with = 1.628( 2), = 1.538(2) measured in white light.It is pleochroic: O yellow, E colorless; O > E. The empirical formula is Na 0.76 Ca 3.11 (UO 2 )(CO 3 ) 3 (Se 1.16 O 3 )F 0.82 O 20.18 H 13.19 based on 21 O + F, U = 1, with C = 3 apfu based on the structure and H set to achieve charge balance.The eight strongest powder X-ray diffraction lines are [d obs (I)(hkl)]: 5.916(100)(104), 4.836(58)(110), 3.744(77)(018), 3.125(33)(211,122), 2.960(60)(214), 2.795(62)(300), 1.828(40)(410) and 1.744(35)(238,146).The structure of szilagyiite (R 1 = 0.0314 for 2335 reflections with I > 2I) is based on infinite sheets built from 3 major components: distorted cubane-like [(SeO 3 ) Ca 3 (F,OH)(H 2 O) 3 ] units, NaO 4 (H 2 O) 3 monocapped trigonal antiprisms, and hexagonal bipyramidal uranyl tricarbonate cluster units, [UO 2 (CO 3 ) 3 ].The sheets are cross-linked by a thin layer of hydrogen bonds formed between interlayer H 2 O bound to Na, with F/OH, and O in the sheets.