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PurposeThe semisolid myelin sheath has very fast transverse relaxation and is invisible to conventional MRI sequences. UTE sequences can detect signal from myelin. The major challenge is the concurrent detection of various water components.MethodsThe inversion recovery (IR)-based UTE (IR-UTE) sequence employs an adiabatic inversion pulse to invert and suppress water magnetizations. TI plays a key role in water suppression, with negative water magnetizations (negative phase) before the null point and positive water magnetizations (positive phase) after the null point. A series of dual-echo IR-UTE images were acquired with different TIs to detect water phase transition. The effects of TR in phase transition and water suppression were also investigated using a relatively long TR of 500 ms and a short TR of 106 ms. The water phase transition in dual-echo IR-UTE imaging of myelin was investigated in five ex vivo and five in vivo human brains.ResultsAn apparent phase transition was observed in the second echo at the water signal null point, where the myelin signal was selectively detected by the UTE data acquisition at the optimal TI. The water phase transition point varied significantly across the brain when the long TR of 500 ms was used, whereas the convergence of TIs was observed when the short TR of 106 ms was used.ConclusionThe results suggest that the IR-UTE sequence with a short TR allows uniform inversion and nulling of water magnetizations, thereby providing volumetric imaging of myelin.

Hydrostatic pressure increases with depth in the ocean, but little is known about the molecular bases of biological pressure tolerance. We describe a mode of pressure adaptation in comb jellies (ctenophores) that also constrains these animals depth range. Structural analysis of deep-sea ctenophore lipids shows that they form a nonbilayer phase at pressures under which the phase is not typically stable. Lipidomics and all-atom simulations identified phospholipids with strong negative spontaneous curvature, including plasmalogens, as a hallmark of deep-adapted membranes that causes this phase behavior. Synthesis of plasmalogens enhanced pressure tolerance in Escherichia coli, whereas low-curvature lipids had the opposite effect. Imaging of ctenophore tissues indicated that the disintegration of deep-sea animals when decompressed could be driven by a phase transition in their phospholipid membranes.

In this study, we investigate the magnetocaloric effects (MCE) and critical behavior of Gd-doped La 0. 6 5 Ca 0. 3 5 − x GdxMnO3 (x = 0 , 0. 1 0 , 0. 1 5) polycrystalline materials. Our results reveal excellent MCE in the Gd-doped samples. Under a magnetic field of 7 T, the full-width at half maximum (Δ T FWHM ) increases from 41 K (x = 0. 0 0) to 121 K (x = 0. 1 0) and 112 K (x = 0. 1 5). Additionally, the refrigerant capacity (RC) is enhanced by 149% and 145% at x = 0. 1 0 and x = 0. 1 5 , respectively, compared to the parent phase. We propose that these improvements can be attributed to the introduction of Gd 3 + ions, which possess smaller ionic radii. This reduction in the average A-site ionic radius weakens the double exchange (DE) interactions, resulting in a more continuous phase transition within the system. Supporting this view, we observe a decrease in magnetization strength after doping, a reduction in Curie temperature ( T C) from 250 K (x = 0. 0 0) to 134 K (x = 0. 1 0) and 130 K (x = 0. 1 5) and a transformation from a first-order to a second-order phase transition in the doped samples. To characterize the critical behavior of the phase transition in the doped samples, we employ the K-F method. The obtained critical exponents for x = 0. 1 0 and x = 0. 1 5 are β = 0. 3 8 0 ± 0. 0 0 6 , γ = 1. 3 2 3 ± 0. 0 0 3 , δ = 4. 4 8 2 ± 0. 0 0 5 and β = 0. 4 7 7 ± 0. 0 0 8 , γ = 1. 0 8 3 ± 0. 0 0 4 , δ = 3. 2 7 0 ± 0. 0 0 2 , respectively. Furthermore, the calculation of the n values suggests a transition of the phase transition in the doped samples from short-range ordering to long-range ordering. [ABSTRACT FROM AUTHOR]

ZrP 2 O 7 is a promising material with excellent thermal and electrical properties. However, when temperature approaches to 563 K, it undergoes a structural phase transition, which will cause large thermal stresses. When Zr is substituted by Y and Nb, a new material of (YNb) 0.2 Zr 0.6 P 2 O 7 , was successfully prepared and the phase transition of material was effectively inhibited. This new material adopts a cubic structure similar to ZrP 2 O 7 , and exhibits medium thermal expansion (α = 7.1 × 10−6 K−1) in the measured range of 200–1073 K. The values of thermal conductivity from RT to 973 K are between 0.4474 W m−1 K−1 and 0.8526 W m−1 K−1, which can be comparable to the values of traditional thermal insulation materials. The dielectric constant and dielectric loss factor at the frequencies above 1 MHz are stable and low. The electrical conductivity of the material indicates that it is electronically insulating at RT-573 K. [ABSTRACT FROM AUTHOR]

This study proposes a methodology for analyzing the precipitation process in mixed‐phase clouds using multisensor satellite data, including radar, lidar, and imager. By leveraging a specific multivariate statistic, we elucidate the vertical microphysical structures of mixed‐phase clouds and their transitions associated with cloud particle growth and phase change. Expanding upon previous warm rain process diagnostics, we integrate cloud thermodynamic phase information from lidar and imager, representing the phase near the cloud top and column, respectively, to classify the vertical microphysical structures obtained from radar. Our global composite analysis reveals a systematic transition from non‐precipitating to precipitating characteristics with increasing ice phase fraction of the cloud column, rather than near the cloud top, and increasing cloud‐top particle size. These findings offer valuable observational references for evaluating numerical models in precipitation physics. Plain Language Summary: To ensure a robust assessment of precipitation physics within global climate and numerical weather prediction models, it is imperative to diagnose the precipitation process using satellite observations on a global scale. Here, we propose a new methodology to address this requirement using multisensor satellite measurements to extend our previously developed method for warm liquid‐phase rain into more general ice‐containing mixed‐phase precipitation. For this purpose, satellite‐based information on the cloud thermodynamic phase obtained from the lidar and imager was exploited to statistically classify the vertical profile characteristics of precipitation observed by radar. The results showed that precipitation tended to occur more efficiently with an increasing ice‐phase fraction of the cloud‐column and the cloud‐top particle size. The statistics derived from observations provide a benchmark for evaluating model precipitation physics, facilitating process‐oriented assessments of numerical models. Key Points: The mixed‐phase precipitation was diagnosed using a combination of multisensor satellite measurements by radar, lidar, and imagerMultivariate statistics were constructed to display the radar reflectivity classified by cloud thermodynamic phase and cloud particle sizeThe statistics show more precipitating character with higher ice‐phase fraction of the cloud optical thickness and cloud‐top particle size [ABSTRACT FROM AUTHOR]

PbZrO 3 (PZO) possesses a unique antiferroelectric-ferroelectric (AFE-FE) phase transition under an external electric field and engages more attention in understanding and regulating the phase transition behavior. In this work, changing annealing temperature (600–750 °C) and ultralow content (5‰) ions doping are used to optimize the phase transition of PZO films via grain size engineering. As annealing temperature increases, the maximum polarization P max increases but forward/backward switching fields E F / E A reduce accompanied by the average grain size enhances from 622 to 686 nm. Following, 5‰ mol aliovalent ion La3+ or K+ doped PZO-650 films both enhance P max and E F / E A indicating the strengthened antiferroelectricity, and meanwhile the grain size enhances to ∼800 nm. A high discharge density of 31 J/cm3 is achieved for 5‰ mol La-doped PZO films at a low electric field of 1 MV/cm, which is ∼100 % higher than those of pure PZO films at different annealing temperatures. This work compares the phase transition characteristics changes in PZO films by changing annealing temperature and ultra-low content ion doping strategy, which would provide new thinking in grain size-engineered antiferroelectric materials for energy storage applications. [ABSTRACT FROM AUTHOR]

A series of NaxMgxSc2 − xW3O12 (0 ≤ x ≤ 0.75) ceramics has been prepared by the coprecipitation process. The phase composition, crystal structure, morphology, and thermal expansion behavior of NaxMgxSc2 − xW3O12 samples were investigated. The results show that (NaMg)3+ substitution causes a phase transition in NaxMgxSc2 − xW3O12. For 0 < x ≤ 0.25, both orthorhombic Sc2W3O12 and hexagonal NaxMgxSc2 − xW3O12 coexist in the sample. For 0.25 < x ≤ 0.75, (NaMg)3+ double cations successfully replace Sc3+, and single‐phase hexagonal NaxMgxSc2 − xW3O12 ceramics were prepared. For x = 1, the impurity MgWO4 was detected. As the (NaMg)3+ codoping amount increases, the grain size grew up and the density of the NaxMgxSc2 − xW3O12 ceramics increased. The coefficients of thermal expansion (CTE) of negative thermal expansion (NTE) NaxMgxSc2 − xW3O12 (0 ≤ x ≤ 0.75) ceramics were improved from −6.02 × 10−6°C−1 to −15.19 × 10−6°C−1 in 30–700°C. Moreover, as the sintering temperature increased, the CTEs of Na0.75Mg0.75Sc1.25W3O12 ceramics were improved from −10.36 × 10−6°C−1 to −13.64 × 10−6°C−1. [ABSTRACT FROM AUTHOR]

The global community is currently grappling with two significant challenges: climate change and the depletion of non-renewable power sources. To address these issues, scientists are paying increased attention to hydrogen as a potential alternative energy carrier, as it is both ecologically favorable and has the potential to replace non-renewable energy sources. However, scientists face difficulties in storing and transporting hydrogen directly. Perovskite hydrides have gained considerable interest as they exhibit excellent ion exchangeability and high gravimetric hydrogen storage capacity. This study specifically examines the hydrogen storage capabilities of NaAlO 3-x H x perovskite using the famous DFT-based CASTEP simulation code. The research reveals that after hydrogen was inserted into the pristine material, the material's cubic structure along with lattice parameters manifests variation. The study also reveals that the hydrogen-incorporated compositions were structurally and thermodynamically stable, with Born's mechanical stability criteria being fulfilled by all compositions. The ductile or brittle nature of the compounds varied with the amount of hydrogen inserted, as shown by Cauchy's pressure and Poisson's ratio. Additionally, the continuous insertion of hydrogen into the pristine material significantly impacted the electronic states, as demonstrated by the density of states and plots of band gap. After the complete insertion of hydrogen, the band gap fell from 5.86 eV to 0 eV, making the final compound metal, it also affects the material's optoelectronic properties. This research provides detailed insights into optical parameters such as absorption, reflectivity, refractive index, extinction coefficient, complex dielectric function, and energy loss function. The gravimetric storage capacity of the material increased from 0.32 wt% to 5.4 wt% after inserting 100% hydrogen into it. NaAlH 3 is determined to be an excellent material for hydrogen storage based on our conclusions. • An innovative perovskite material for hydrogen storage has been presented. • GGA-PBE approximation was employed in DFT-based calculations. • The formation enthalpies of all compositions ensure their synthesizability. • The hydrogen storage capacity of 5.4% by weight is appropriate for advanced hydrogen storage techniques. • All the compounds are thermodynamically and mechanically stable. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) represent a promising technology for next‐generation photovoltaics, yet scaling up from laboratory to industrial production via the solution spin‐coating method encounters significant challenges. Vacuum deposition offers a potential alternative but struggles with controlling perovskite phases and ensuring sufficient precursor reactions. Here, the study presents a hybrid evaporation‐solution approach using a large cation‐based pseudo‐halogen anion salt (guanidine thiocyanate) and a compensating cation salt (methylammonium iodide) as co‐additives to finely modulate the phase transition process. This approach eliminates the need for intermediate‐phase transitions, promotes sufficient precursor reactions, and facilitates the formation of highly oriented α‐phase perovskites prior to annealing. Consequently, it prevents detrimental δ‐phase formation, yielding enlarged, homogeneous perovskite grains with significantly reduced defects. The resulting p‐i‐n‐structured PSCs achieve a maximum efficiency of 24.72% and a low open‐circuit voltage loss of 0.377 V, coupled with significantly improved stability. The work integrates the advantages of vacuum deposition and solution processing, providing new insights into perovskite phase transitions and paving the way for the efficient, scalable production of high‐performance PSCs. [ABSTRACT FROM AUTHOR]

Chiral materials exhibit distinctive properties that improve the performance of organic solar cells (OSCs). In this study, chiral PM6 is integrated into PM6:PY‐IT blends to fabricate chiral quasi‐binary OSCs (cOSCs). The produced devices displayed an increased short‐circuit current and fill factor, achieving a peak efficiency of 16.60% compared to 15.96% for the standard PM6:PY‐IT cell. Additionally, the incorporation of chiral PM6 significantly enhanced the thermal stability, with the cOSCs retaining over 80% of their initial efficiency after 1000 h of operation. The steric effect of chiral PM6 altered the molecular packing, thereby improving the overall crystallinity. The optimized nanoscale domain morphology resulted in a more effective blend film, leading to superior device performance. Moreover, the chirality‐induced orbital angular momentum increased the ratio of triplet states, which is a key factor for increasing the photocurrent in OSCs. The delocalization of electron wavefunctions is driven by chiral steric effects, and it diminished the Coulomb attraction between the interfacial electron–hole pairs, which enhanced the efficient charge generation. This study provides valuable insights into the role of chirality in optimizing both the performance and stability of OSCs. [ABSTRACT FROM AUTHOR]

Advanced optical information encryption usually relies on the integration of multicolor, stimulus‐responsive, and afterglow luminescence. However, achieving these simultaneously within a single‐phase system has posed challenges, complicating the design process. In this study, an advanced 3D information encryption strategy is presented based on undoped and alloyed Cs₂CdCl₄, encrypted through three distinct channels: emission wavelength, water stimulation, and afterglow time. Specifically, Mn2+, Sb3+, and Ag+ doped Cs₂CdCl₄ single crystals are successfully synthesized via a modified hydrothermal method, which exhibit bright orange, green, and blue emissions, respectively. Decryption of specific information can be achieved by employing corresponding narrowband filters. Furthermore, the Cs₂CdCl₄ system demonstrates hydrochromism, attributed to water‐induced sequential phase transitions. Upon water treatment, the 2D Cs₂CdCl₄ will undergo a phase transition to Cs3Cd2Cl7, and finally to cubic CsCdCl3. Interestingly, the resultant CsCdCl3 exhibits pronounced afterglow, originating from the triplet emission of Cd ions. Leveraging these unique properties, a highly secure and adjustable 3D encrypted quick response code is designed. The encrypted information is encoded in coordinates, and decrypted information can be retrieved in both compressed and decompressed modes as required. These findings pave the way for the development of novel smart photonic materials and multimodal optical information encryption. [ABSTRACT FROM AUTHOR]

Ceramic compounds BaTi 1-x Fe x O with x = 0–0.2 prepared by solid state reaction technique were studied using X-ray diffraction, Raman spectroscopy, and magnetometry methods focusing on the correlation between the structure and magnetic properties. Chemical doping with Fe ions leads to a concentration driven structural transformation from the single phase tetragonal (T-) structure to the hexagonal (H-) structure with a mixed structural state stable in the concentration range 0.06 < x ≤ 0.2. Increase in the Fe ions content causes a stabilization of weak ferromagnetic state driven by the exchange interactions Fe3+ – O – Fe3+ ions strongly dependent on the structural positions of the Fe ions. Increase of the dopant content above x = 0.08 leads to a decrease of the remnant magnetization which is mainly caused by a stabilization of Fe4+ ions as well as by the lattice defects associated with oxygen vacancies formed to keep electroneutrality of the compounds. The results of the structural and magnetization measurements allowed to itemize the type of exchange interactions between Fe ions residing different structural positions of the hexagonal lattice as well as to reveal structural instability of the T- and H- phases under ambient conditions and applied electric field which shows a possibility to control the structure and magnetic properties of the mixed compounds via external stimuli. [ABSTRACT FROM AUTHOR]

Cage‐confinement effect that imposes great constriction on the dynamic behaviors of guest molecules is an established platform for tailoring physical properties. Herein, the strategy of enhancing cage‐confinement effect to control molecular motion has been probed for the first time to exploit new high‐Tc ferroelectrics of 2D hybrid perovskites. By fine‐tailoring of the confined cations inside the perovskite cavities, we have successfully obtained new homologous ferroelectrics of (BA)2(MA)2Pb3Cl10 (1; BA=n‐butylamine, MA=methylamine) and (BA)2(EA)2Pb3Cl10 (2; EA=ethylamine). Intriguingly, this dynamics modulation of cage‐confined cations leads to a remarkable promotion of Curie temperature (Tc), boosting from 340 K (for 1) to 402 K (for 2). In situ solid‐state NMR spectroscopy and theoretical simulations on energy barrier confirm that the larger EA cation in 2 is subject to stronger confinement effect, of which potential energy barrier of molecular motion is ~3.5 times that of MA cation. This dynamic behavior greatly suppresses the dynamic motions of EA cation, while MA cation can easily accelerate motion and reach a fast motion limit, thus accounting for an enhancement of Tc (ΔT~62 K) in 2. The finding sheds light on the understanding of cage‐confined electric orders and the precise design of high‐performance ferroelectrics. [ABSTRACT FROM AUTHOR]

Single‐crystal growth, differential thermal analysis (DTA), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X‐ray structural studies and polarized microscopy observations of bis(ethylenediammonium) tetrabromozincate(II) bromide [NH3(CH2)2NH3]2[ZnBr4]Br2 are presented. A reversible phase transition is described. At room temperature, the complex crystallizes in the monoclinic system. In some cases, the single crystals are twinned into two or more large domains of ferroelastic type with domain walls in the (100) crystallographic plane. DTA and DTG measurements show chemical stability of the crystal up to ∼538 K. In the DSC studies, a reversible isostructural phase transition was revealed at ∼526/522 K on heating/cooling run, respectively. Optical observation on the heating run reveals that at the phase transition the plane of twinning (domain wall) does not disappear and additionally the appearance of a new domain structure of ferroelastic type with domain walls in the planes (101), (101), (100) and (001) is observed. The domain structure pattern is preserved after cooling to the room‐temperature phase and the symmetry of this phase is unchanged. [ABSTRACT FROM AUTHOR]

Small-scale pumps for controlling microfluidics have promising applications in drug delivery and chemical assays. Liquid metal (LM) demonstrates excellent flow pumping performance due to its simple structure and the electrocapillary effect under an electric field. However, LM droplets risk escaping from constrained structures, which can lead to pump failure. Temperature regulation is also a critical parameter in optimizing chemical reactions in fluidic systems, however, integrating it into a compact system remains challenging. Here, we develop a temperature-triggered gallium-based actuator (TTGA) by introducing a gallium (Ga) droplet wetted on a copper (Cu) plate as the core element for flow actuation. The Cu plate prevents the Ga droplet from escaping the chamber and significantly increases the flow rate. By leveraging the electrochemical method to inhibit the supercooling effect of Ga, the TTGA enables activation/deactivation for flow actuation at different temperatures. We investigate the impact of electrode position, solution concentration, and applied voltage on TTGA's pumping efficiency. By dynamically tuning the Ga droplet's temperature to control phase transition, TTGA allows for accurate flow actuation control. Furthermore, placing Ga and eutectic Ga-indium (EGaIn) droplets in different channels enables the expected flow divergence for fluids with different temperatures. The development of TTGA presents new opportunities in microfluidics and biomedical treatment. [ABSTRACT FROM AUTHOR]

We investigated pressure-induced changes in pyrochlore iridates ( A 2 Ir 2 O 7 , A = Pr, Gd, Dy and Er) using Raman spectroscopy and X-ray diffraction. All four compounds exhibited a pressure-driven isostructural transition associated with the rearrangement of IrO 6 octahedra in the pyrochlore lattice. Interestingly, the critical pressure ( P c ) for this transition correlates inversely with the A-site cation radius, P c decreased from ∼ 10.8 GPa (Er, smallest cation) to ∼ 7.5 GPa (Pr, largest cation). Additionally, the bulk modulus systematically decreases with increasing ionic radius of A-site across the A 2 Ir 2 O 7 series. High-pressure Raman spectroscopy revealed anomalous decrease of the linewidth with increasing pressure for Ir–O ( T 2 g 4 ) and Ir–O–Ir ( A 1 g and E g ) vibrational modes, suggesting a suppression of electron–phonon coupling due to enhanced electronic bandwidth under pressure. [ABSTRACT FROM AUTHOR]

A review of the author's data, partly still unpublished, on studying of liquid tellurium and cesium is given. No definite proofs indicating phase transitions in these liquids were found. New developments in studying the liquid–liquid phase transition are briefly described. [ABSTRACT FROM AUTHOR]

This study aims to understand the phase transitions, between congested and free-flow states, by estimating the congestion boundary. Since the congestion transition process occurs rapidly, the probability density distributions of traffic flow parameters, i.e. speed and density, show bimodal shapes. The congestion boundary is defined as the threshold that decomposes the bimodal distribution. The dedicated short-range communication data and toll collection system data were used to estimate congestion boundaries on the highway section from Seoul tollgate to Shingal junction. The results show that the congestion boundaries for speed, density, and flow rate were estimated to be 66.9 km/h, 22.8 veh/km, and 341.3 veh/5 min, respectively. With the flow rate at the congestion boundary, the capacity was estimated to be between 71.4% and 82.7% of traditional capacities. The congestion boundary approach provides critical thresholds for each dynamic transition phase on highways, offering crucial insights for effective congestion management. [ABSTRACT FROM AUTHOR]

We consider a model for a social network with N interacting social actors. This model is a system of interacting marked point processes in which each point process indicates the successive times in which a social actor expresses a "favorable" ( + 1 ) or "contrary" ( - 1 ) opinion. The orientation and the rate at which an actor expresses an opinion is influenced by the social pressure exerted on this actor. The social pressure of an actor is reset to 0 when the actor expresses an opinion, and simultaneously the social pressures on all the other actors change by h/N in the direction of the opinion that was just expressed. We prove propagation of chaos of the system, as N diverges to infinity, to a limit nonlinear jumping stochastic differential equation. Moreover, we prove that under certain conditions the limit system exhibits a phase transition described as follows. If h is smaller or equal than a certain threshold, the limit system has only the null Dirac measure as an invariant probability measure, corresponding to a vanishing social pressure on all actors. However, if h is greater than the threshold, the system has two additional non-trivial invariant probability measures. One of these measures has support on the positive real numbers and the other is obtained by symmetrization with respect to 0, having thus support on the negative real numbers. [ABSTRACT FROM AUTHOR]

In the case of low-temperature fabrication aiming at transparent polycrystalline YAG ceramics with fine grain size, it is easy to retain trace amounts of the intermediate YAP phase, thereby reducing the optical transmittance. To address this issue, adding a small amount of Al 2 O 3 to the starting YAG powder was found to promote the transformation of the residual YAP phase to the YAG phase at low temperatures. The study investigated the effect of sintering temperature and excess Al 2 O 3 amount on preparing transparent YAG ceramics by hot pressing. The transmittance of the Al 2 O 3 -aided single-phase YAG ceramic (2 mm thick) prepared using the two-step sintering reached 43.4 % at 400 nm and 71.8 % at 1064 nm, with a grain size of about 2 μm, while the transmittance of the multiphase YAG ceramic without Al 2 O 3 addition was less than 1 % at both wavelengths. [ABSTRACT FROM AUTHOR]

In the present paper, we study the weakly periodic p-adic quasi-Gibbs measures for the three-state Potts model on a Cayley tree of order two. Under some conditions, we show there exist 14 weakly periodic (non-periodic) p-adic quasi-Gibbs measures. Moreover, if p = 3 then there are six weakly periodic p-adic Gibbs measures for this model. We also prove that if p ≠ 3 then a phase transition occurs for the Potts model on a Cayley tree of order two. [ABSTRACT FROM AUTHOR]

The model of ice surface softening is represented by a system of three one-dimensional partial differential parabolic equations, taking into account the spatial inhomogeneity. Using one-mode and adiabatic approximations, an analytical soliton solution of a one-dimensional Ginzburg–Landau differential equation for the spatial normal distribution of shear strain to the ice surface is obtained. The analytical form of the numerical procedure for solving the equations, including initial and boundary conditions, is written on the basis of an explicit two-layer difference scheme. The distributions of time and stationary values of static friction force, kinetic friction force and temperature are constructed. Two cases were considered: 1) the upper and lower surfaces move with equal velocities in opposite directions; 2) the upper surface moves along the stationary lower surface. The dependencies of stress, strain and temperature on the coordinate in the normal direction to the surface are determined for different time series. It is shown that a stationary distribution of friction forces and temperature along the thickness of the near-surface ice layer is established with time. The values of the kinetic and static friction forces in the near-surface ice layer increase monotonically with distance from the friction surfaces, while the coordinate dependence of the temperature has a nonmonotonic appearance. The stationary values of the static friction force in the near-surface ice layer decrease with increasing temperature of the friction surfaces, indicating that the surface transforms to a more liquid-like state, while the coordinate dependence has a monotonically increasing form. [ABSTRACT FROM AUTHOR]

Bismuth ferrite (BiFeO3)‐based high‐temperature piezoelectric ceramics have high Curie temperatures and excellent thermal stability; however, their applications are limited by inadequate piezoelectric performance due to large coercive fields and high leakage conduction. This study investigates the impact of MnO2 doping on the phase transition, defect structure, domain morphology, as well as the dielectric, ferroelectric, and electrical conduction behaviors of 75BiFeO3–25BaTiO3 ceramics sintered under an oxygen atmosphere. A structural transformation from distorted rhombohedral to pseudo‐cubic symmetry was observed with increasing MnO2 content, accompanied by domain fragmentation. MnO2 doping at an appropriate level inhibited defects such as Fe′Fe$\ {\mathrm{F}}{{{\mathrm{e^{\prime}}}}_{{\mathrm{Fe}}}}$ and VO2−⋅⋅$V_{{{{\mathrm{O}}}^{{\mathrm{2}} - }}}^{\centerdot \centerdot }$. Regarding electrical properties, the reduction in rhombohedral distortion and enhancement in the pseudo‐cubic phase after MnO2 doping resulted in decreased remanent polarization and electrostrain, which could potentially hinder piezoelectric response. However, appropriate MnO2 doping effectively reduced leakage conduction, significantly enhancing the poling efficiency of the ceramics. The maximum d33 value of 107 pC/N and kp of 0.36 were achieved at an MnO2 doping content of 0.1 wt.%. Excessive MnO2 addition may generate 2Mn′Ti−VO2−⋅⋅${\mathrm{2M}}{{{\mathrm{n^{\prime}}}}_{{\mathrm{Ti}}}}-V_{{{{\mathrm{O}}}^{{\mathrm{2}} - }}}^{\centerdot \centerdot }$ defect dipoles, as indicated by increased coercive field (Ec) and dielectric loss. The observed increase in high‐temperature resistivity with MnO2 content is primarily attributed to reduced grain size and increased concentration of mobile defects. This study provides valuable insights for further research on the application of 75BiFeO3–25BaTiO3 systems in high‐temperature piezoelectric devices. [ABSTRACT FROM AUTHOR]

Through molecular dynamics simulation, it is observed that the [001] oriented tetragonal zirconia nanopillars have two linear elastic deformation stress-strain relationships under tensile load. This phenomenon is the result of the phase transition from tetragonal structure to monoclinic structure. In order to further clarify the stress-strain curve, detailed studies including crystal structure analysis and atomic strain calculation were per- formed. The lattice orientation strongly affects the plastic deformation mechanism, that is, the [001] and [111] oriented nanopillars undergo phase transition under tensile load, while the [110] oriented nanopillars lead to brittle fracture. A significant temperature effect was observed. As the temperature increases from 300K to 1500K, the elastic modulus decreased linearly from 573.45GPa to 482. 65GPa. In addition, the phase transition energy barrier is estimated by the light elastic band (NEB) theory, and it is observed that the phase transition energy barrier decreases with increasing temperature. This work will help to deepen the understanding of tetra- gonal to monoclinic phase transition and nano-scale mechanical behavior of zirconia. [ABSTRACT FROM AUTHOR]

Polybutene (PB) is a typical polymer with various crystal forms: I, II, III, and I′. Among them, the mechanical properties of Form I PB is better but only Form II crystal can be obtained from the melt due to the kinetic advantage and then transform to Form I slowly. While the slow phase transition rate restricts its application. Partial melting is applied to accelerate the phase transition, which was studied by Flash DSC. The results indicated that the phase transition behavior during partial melting shows dependence on the isothermal crystallization temperature and 70 °C is optimal, which can reduce the phase transition time from 20 h to 200 s. As the crystallization temperature determined, stepwise crystallization was used to accelerate the phase transition. The influence of nucleating temperature and time was investigated and the results indicated that 0 °C and 2 s are the best temperature and time, respectively. With stepwise crystallization, the phase transition time was further reduced to 50 s. Moreover, stepwise crystallization can increase the content of Form I crystal from 80.0% to 98.2%. The mechanism of phase transition during partial melting was proposed according to the results, which can supplement the existing phase transition mechanism. [ABSTRACT FROM AUTHOR]

Single‐crystal growth, differential thermal analysis (DTA), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X‐ray structural studies and polarized microscopy observations of bis(ethylenediammonium) tetrabromozincate(II) bromide [NH3(CH2)2NH3]2[ZnBr4]Br2 are presented. A reversible phase transition is described. At room temperature, the complex crystallizes in the monoclinic system. In some cases, the single crystals are twinned into two or more large domains of ferroelastic type with domain walls in the (100) crystallographic plane. DTA and DTG measurements show chemical stability of the crystal up to ∼538 K. In the DSC studies, a reversible isostructural phase transition was revealed at ∼526/522 K on heating/cooling run, respectively. Optical observation on the heating run reveals that at the phase transition the plane of twinning (domain wall) does not disappear and additionally the appearance of a new domain structure of ferroelastic type with domain walls in the planes (101), (101), (100) and (001) is observed. The domain structure pattern is preserved after cooling to the room‐temperature phase and the symmetry of this phase is unchanged. [ABSTRACT FROM AUTHOR]

The non-isothermal crystallization dynamic behavior and mechanism of plasma sprayed Fe48Cr15Mo14C15B6Y2 coating were thoroughly studied. The phase transition and crystallization kinetics of the coating were elaborately investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The findings reveal that the characteristic temperatures of the coating shift to an elevated temperature at a higher heating rate and the crystallization processes are thermally activated. The 3-rd step of crystallization processes is more susceptible to the continuously increased heating rate while the onset crystallization reaction is less sensitive to the continuously enhanced heating rate. Fe23(C, B)6 phase is inclined to precipitate than other crystal phases due to the substantial pre-generation of α-Fe. The onset nucleation and growth of α-Fe crystals is tough due to a higher onset apparent activation energy. Meanwhile, the transformation from Fe23(C, B)6 to FeB is harder in comparison with the precipitation of other crystals. The most parts of the three crystallization processes are dominated by three-dimensional diffusion model due to the fact that most values of local Avrami exponent are higher than 2.5. [ABSTRACT FROM AUTHOR]

In ordered to understand the electronic structure, structural phase stability, magnetic properties, and Fermi surface studies of the 122 type of SrFe2X2, where (X = P, As, Sb) were investigated. For this purpose, the plane wave self-consistent method was used. Using the Brich–Murnaghan equation, their electronic structure and magnetic ordering were also investigated. It was understood that, under pressure, the compound SrFe2As2 undergoes a structural phase change from the tetragonal phase into the collapsed tetragonal phase. Further, due to their larger lattice constants, antimonides with larger local iron magnetic moment exhibit an enhanced Hund's rule coupling. Furthermore, smaller intra-atomic exchange coupling and significantly smaller lattice constants may be the cause of the extremely small local Fe moment for phosphates. The analysis of the valence charge density in the collapsed tetragonal phase demonstrates that the interactions between As atoms are more pronounced when compressed along the c-axis. The strength of this interaction is primarily governed by the Fe-As chemical bonding. The collapsed tetragonal phase of SrFe2As2 compounds, as observed in Fermi surface studies, indicates the absence of nesting of Fermi surfaces. It is clear that, from the studies, the tetragonal phase of Fermi surface nesting resulted in the long-range magnetic order, leading to the presence of superconductivity. [ABSTRACT FROM AUTHOR]

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The crystal structure and vibrational spectra of CoFe2O4 ferrite were studied using X-ray diffraction and Raman spectroscopy over a pressure range of 0–35GPa. A structural phase transition from the cubic Fd3̄m phase to the post-spinel orthorhombic Bbmm phase occurs at a pressure of approximately 23GPa through a two-phase region. Pressure-induced changes in the structural parameters, lattice distortion, and vibrational modes of the studied ferrite were investigated in detail. Lattice parameters, bond lengths, compressibility, and bulk modulus for both the cubic and orthorhombic phases of CoFe2O4 were determined. [ABSTRACT FROM AUTHOR]

The properties of molybdenum diboride are intricately tied to its crystal structure, which includes two distinct phases, α‐MoB2 and β‐MoB2. The α‐MoB2 exhibits superior electrical and catalytic properties, akin to those of graphite due to the similar HCP structure. Nevertheless, the transformation between α‐MoB2 and β‐MoB2 is complicated and the formation of α‐MoB2 remains challenge due to higher Gibbs free energy. The MoB2 powder synthesized through boro/carbothermal reduction in this study suggests the β phase, transforming into α‐MoB2 completely via a high‐entropy strategy. It founds that the introduction of high‐entropy diborides (HEB) effectively inhibits the grain growth of samples, resulting in a significant enhancement in their hardness. The potential for the formation of a single‐phase between MoB2 and HEB is associated with Pauling electronegativity difference, δχP. Furthermore, the formation of a single‐phase solid solution was found to contribute to the improvement in the fracture toughness of the samples. This work presents a novel strategy for stabilizing α‐MoB2, offering valuable insights into understanding phase‐transition behavior in MoB2 and the solid solubility in multi‐component ceramics. [ABSTRACT FROM AUTHOR]

Vanadium dioxide (VO2), renowned for its reversible metal‐to‐insulator transition (MIT), has been widely used in configurable photonic and electronic devices. Precisely tailoring the MIT of VO2 on micro‐/nano‐scale is crucial for miniaturized and integrated devices. However, existing tailoring techniques like scanning probe microscopy, despite their precision, fall short in efficiency and adaptability, particularly on complex or curved surfaces. Herein, this work achieves the local engineering of the phase of VO2 films in high efficiency by employing laser writing to assist in the hydrogen doping or dedoping process. The laser doping and laser dedoping technique is also highly flexible, enabling the fabrication of reconfigurable, non‐volatile, and multifunctional VO2 devices. This approach establishes a new paradigm for creating reconfigurable micro/nanophotonic and micro/nanoelectronic devices. [ABSTRACT FROM AUTHOR]

The polymorphic nature of In2Se3 leads to excellent phase‐dependent physical properties including ferroelectricity, photoelectricity, and especially the intriguing phase change ability, making the precise phase modulation of In2Se3 of fundamental importance but very challenging. Here, the growth of In2Se3 with desired‐phase is realized by temperature‐controlled selenization of van der Waals (vdW) layered bulk γ‐InSe. Detailed results of Raman spectroscopy, scanning electron microscopy (SEM), and state‐of‐the‐art spherical aberration‐corrected transmission electron microscopy (Cs‐TEM) clearly and consistently show that β‐In2Se3, 3R α‐In2Se3, and 2H α‐In2Se3 can be perfectly obtained at ≈270, ≈300, and ≈600 °C, respectively. Further comprehensive atomic imaging analyses confirm that the seeding material, InSe, plays a critical role in the low‐temperature epitaxial growth of vdW‐layered In2Se3, and, more interestingly, β‐In2Se3 acts as an intermediate phase between 3R and 2H α‐In2Se3 transitions. This investigation not only provides a simple yet versatile strategy for the phase modulation of In2Se3, but also sheds light on the temperature‐dependent phase evolution of In2Se3. [ABSTRACT FROM AUTHOR]

Amorphous solids are a type of condensed matter characterized by the absence of long-range order in their lattice structure. However, they still exhibit short- or medium-range order, which contributes to their versatile local and global electronic and chemical properties. Recently, 2D amorphous solids have gained attention for their exceptional mechanical and electronic features, which are unattainable in conventional crystalline materials. This review highlights the physical properties of ultrathin 2D amorphous solids, which are formed through covalent bonding and feature polyhedron structures with shared edges and corners. Two notable examples of 2D amorphous solids include honeycomb-structured nanosheets with mixed hybrid orbitals and layered materials with reduced coordination numbers of the elements. We provide an in-depth discussion of (1) the phase transition between crystalline and amorphous phases in 2D solids, (2) advanced synthetic methods for producing high-quality amorphous films with precise thickness control, and (3) the potential applications of sub-nanometer scale 2D amorphous solids. Lastly, we explore their potential to revolutionize the design of highly versatile electronic devices at sub-nanometer scales. [ABSTRACT FROM AUTHOR]

Constructing metastable phase structure plays an important role in changing the physicochemical properties and improving the catalytic performance of nanocrystals. Unfortunately, the synthesis of metastable phase metallic nanocrystals is highly challenging, mainly due to the thermodynamically unstable ground‐state. Here, we report a synthesis of unconventional metastable hexagonal rhodium nanocrystal (Bint−Rhhcp/C) via interstitial boron insertion. The insertion of boron atoms into the interstitial sites of cubic Rh lattice not only induces the atomic arrangements from face‐centered cubic (fcc) to hexagonal close‐packed (hcp), but also stabilizes the metastable hexagonal Rh structure. Benefiting from the phase transition and interstitial boron doping, the Bint−Rhhcp/C catalyst exhibits remarkable catalytic performance toward hydrogen oxidation reaction (HOR) under alkaline media, with a mass activity of 1.413 mA μgPGM−1. Experimental measurements including in situ surface‐enhanced infrared absorption spectroscopy (SEIRAS) and density functional theory (DFT) calculations indicate that the strengthened adsorption of hydroxyl species on the electrode surface of Bint−Rhhcp/C is responsible for the reconstruction of interfacial water structure and increased water proportions in the gap region in the electric double layers. As a result, the increased water connectivity and hydrogen bond network facilitate high‐efficiency hydrogen transfer across the interface, thereby boost the alkaline HOR performance. [ABSTRACT FROM AUTHOR]

Polymer-based composites, due to their versatility and tunable properties, have become essential in sorption, energy storage, and sensing applications. This review explores the fundamental chemistry underlying phase transitions within polymer matrices during composites formation, examining how anisotropic and isotropic fillers influence the mechanical, thermal, and functional properties of polymer-based composites. The role of phase transitions is emphasized as a key factor shaping the composite properties, while porosity is highlighted as a crucial attribute impacting sorption processes (absorption and adsorption) which enhances the utility of these materials in diverse modern applications. The transformations within polymer matrices during composites development and their resultant applications in sorption, sensing, and energy storage are investigated. It is examined how filler types and morphologies affect the porosity and functional performance of polymer-based composites. Future challenges and strategies for advancing the performance and sustainability of these materials are also outlined, offering insights that support ongoing research and development in advanced polymer-based composites. The review provides an analysis of current advancements and also offers guidance for future research, making it valuable for both emerging and established researchers in the field. [ABSTRACT FROM AUTHOR]

A new haloargentate hybrid, [Et‐dabco]₂Ag₂Br₄ (1) (Et‐dabco+=1‐Ethyl‐1,4‐diazabicyclo[2.2.2]octan‐1‐ium), has been successfully synthesized by a solution diffusion method and characterized using microanalysis, single crystal X‐ray diffraction, variable‐temperature powder X‐ray diffraction (PXRD), differential scanning calorimetry (DSC), and dielectric spectra. The crystal structure of 1 at 273 K contains one‐dimensional (1D) anionic [Ag₂Br₄]2− chains, with the [Et‐dabco]+ cations embedded in the gaps between the inorganic chains. Hybrid 1 underwent a reversible structural phase transition (SPT) at around 464.5 K on heating, and the Pawley refinement revealed similar crystal structures in the low‐ and high‐temperature phases. The SPT endows 1 with switchable and bistable dielectric properties. Combined with previous studies, it was revealed that the self‐assembly of silver halide (AgX) with the lower rotational energy barrier of 1‐alkyl‐1,4‐diazabicyclo[2.2.2]octan‐1‐ium in solution probably achieves new phase transition materials. [ABSTRACT FROM AUTHOR]

Integrating multiple switching behaviors in a single material is conducive to the development of smart devices, but still faces challenges, especially in finding new types of multiresponsive materials. Hybrid metal halides have been becoming promising candidates with the potential to exhibit changes in various physical and chemical properties upon structural phase transitions. Herein, a pair of enantiomers (R/S‐3‐OHPD)PbI3 (1R/1S; 3‐HOPD = 3‐hydroxypiperidine cation) is reported to show multichannel switching behaviors around room temperature triggered by a combined order‐disorder and displacive type phase transition that arouses a large lattice reorganization and shape change of the crystals. Owing to the inherent chiral, noncentrosymmetric, and semiconducting characteristics of the compounds, five other switching behaviors are realized besides the macroscopic deformation, that is, enthalpy, dielectric permittivity, photoluminescence, circularly polarized light excited photoluminescence, and photoelectric response. This study provides an exciting example of phase transition crystals for the development of integrated multifunctional materials. [ABSTRACT FROM AUTHOR]

Based on the shock-loading technique of a two-stage light gas gun, the yield strength of copper was measured by the shock wavefront disturbance method for the first time. Additionally, based on Steinberg–Cochran–Guinan constitutive model, a numerical simulation procedure for the evolution of perturbed shock front in copper was first constructed. Combining numerical simulation results with experimental results, the yield strength of copper was found to be 0.72 ± 0.01, 0.99 ± 0.02, 1.31 ± 0.02, 1.65 ± 0.03 and 1.82 ± 0.02GPa at pressures of 47.17, 60.67, 76.98, 101.35 and 124.26GPa, respectively. The results were in good agreement with those obtained by the AC method. According to the phase diagram of copper, there was no phase transition under experimental shock-loading pressure, and the yield strength of copper increased with increasing shock-loading pressure. Research on the yield strength of copper under shock loading was of great significance to various fields. [ABSTRACT FROM AUTHOR]

Comprehensive Summary The pursuit of advanced sodium‐ion batteries (SIBs) has been intensified due to the escalating demand for sustainable energy storage solutions. A W‐doped P2‐type layered cathode material, Na0.67Ni0.246W0.004Mn0.75O2 (NNWMO), has been developed to address the limitations of traditional cathode materials. Compared to the pristine Na0.67Ni0.25Mn0.75O2 (NNMO), NNWMO exhibits improved reversible capacity, excellent cycle performance, and remarkable rate performance. It can deliver an increased discharge capacity of 142.20 mAh/g at 0.1 C, with an admirable capacity retention of 80.5% after 100 cycles at high voltage. In situ XRD results demonstrate that the rivet effect related to the strong W—O bonds inhibits irreversible phase transition and enhances structural reversibility during charge/discharge processes. High‐resolution scanning transmission electron microscopy and X‐ray diffraction results confirm successful lattice doping of W6+ and increased layer spacing, contributing to favorable sodium ion diffusion kinetics. Density‐functional theory (DFT) calculation results further reveal that the smoother Na+ ion diffusion dynamics is attributed to the reduced migration energy barrier of Na+ with the insertion of W6+. This study provides valuable insights into the design of high‐performance cathode materials for next‐generation SIBs, showcasing the potential for more efficient, stable, and enduring energy storage solutions. [ABSTRACT FROM AUTHOR]

Perovskite oxide Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3‒δ (BSCF) is a highly active cathode material widely studied for intermediate temperature solid oxide fuel cells (IT-SOFCs), however, the tendency of phase transition of BSCF under IT-SOFC operating conditions poses a critical challenge for its reliable applications. Here, a multiphase BSCF-Gd 0.1 Ce 0.9 O 1.95 (GDC) nanocomposite with heterogeneous interfaces is synthesized at a relatively low calcination temperature of 750 °C. Both the multiphase composition and microstructural morphology of the nanocomposite are very stable during annealing at 750 °C. The unique multiphase structure and ultrafine microstructure of the nanocomposite can be maintained in the resultant cathode through a sintering-free direct assembly fabrication method. As a consequence, a corresponding single cell based on the BSCF-GDC nanocomposite cathode generates a maximum power density of 1.41 W cm−2 at 750 °C with outstanding galvanostatic stability for 100 h. This work provides an effective means for the design and utilization of highly active BSCF-based nanocomposite cathodes for durable IT-SOFCs. [ABSTRACT FROM AUTHOR]

A new haloargentate hybrid, [Et‐dabco]₂Ag₂Br₄ (1) (Et‐dabco+=1‐Ethyl‐1,4‐diazabicyclo[2.2.2]octan‐1‐ium), has been successfully synthesized by a solution diffusion method and characterized using microanalysis, single crystal X‐ray diffraction, variable‐temperature powder X‐ray diffraction (PXRD), differential scanning calorimetry (DSC), and dielectric spectra. The crystal structure of 1 at 273 K contains one‐dimensional (1D) anionic [Ag₂Br₄]2− chains, with the [Et‐dabco]+ cations embedded in the gaps between the inorganic chains. Hybrid 1 underwent a reversible structural phase transition (SPT) at around 464.5 K on heating, and the Pawley refinement revealed similar crystal structures in the low‐ and high‐temperature phases. The SPT endows 1 with switchable and bistable dielectric properties. Combined with previous studies, it was revealed that the self‐assembly of silver halide (AgX) with the lower rotational energy barrier of 1‐alkyl‐1,4‐diazabicyclo[2.2.2]octan‐1‐ium in solution probably achieves new phase transition materials. [ABSTRACT FROM AUTHOR]

Silk‐based materials are sought after across various industries due to their remarkable properties, including high strength and flexibility. However, their practical application depends largely on how well these properties are maintained under different environmental conditions. Despite significant advancements in the large‐scale production of artificial silk fibers, the effects of temperature on their mechanical behavior are understudied. In this study, the mechanical properties of artificial spider silk fibers between −80 and +120 °C are examined and compared to both synthetic and natural silk fibers. The findings reveal that artificial silk fibers maintain their strength up to +120 °C, though the strain at break slightly decreases, remaining above 60%. At −80 °C, the fibers exhibit increased strength, but the strain at break is reduced. While these artificial fibers closely mimic the behavior of natural silk, they show a noticeable reduction in extensibility at low temperatures. Complementing experimental data, differential scanning calorimetry, and thermogravimetric analysis are also conducted, proposing a simple physical model to explain the observed temperature‐induced softening. Encouragingly, the degradation temperature of artificial silk is comparable to that of native silkworm and spider silk. This study underscores the importance of enhancing the mechanical robustness of artificial silk to expand its applications. [ABSTRACT FROM AUTHOR]

This study explored the structural, vibrational, morphological, optical, and magnetic characteristics of both as-grown and annealed single crystals of tin telluride (SnTe), employing diverse analytical techniques. X-ray powder diffraction (XRD) analysis shows the cubic lattice structure of SnTe with consistent lattice parameters across different temperatures, along with the phase transition phenomenon. Fourier Transform Infrared Spectroscopy (FTIR) elucidates temperature-induced shifts in vibrational modes, indicating sensitivity to thermal stimuli. Scanning electron microscopy (SEM) reveals layer-by-layer growth patterns and temperature-dependent variations in crystal morphology. Energy-dispersive X-ray analysis (EDAX) confirms the synthesized crystals' high purity and slight tellurium-rich composition. Optical band gap measurements demonstrate an increase in band gap upon annealing, attributed to valence band convergence. Field-dependent magnetization (M − H) curves exhibit ferromagnetic properties at ambient temperature, which escalate with increasing annealing temperature. Electron Paramagnetic Resonance (EPR) spectra reveal spin mobility and exchange coupling, with variations in the g-factor suggesting the presence of additional spin entropy. These observations offer significant insights into the complex properties of SnTe, which are crucial for its potential applications across various technological fields. [ABSTRACT FROM AUTHOR]

An explicit form of weak solutions to the Riemann problem for a degenerate nonlinear parabolic equation with a piecewise constant diffusion coefficient is found. It is shown that the lines of phase transitions (free boundaries) correspond to the minimum point of some strictly convex and coercive function of a finite number of variables. A similar result is true for Stefan's problem. In the limit, when the number of phases tends to infinity, there arises a variational formulation of self-similar solutions to the equation with an arbitrary nonnegative diffusion function. [ABSTRACT FROM AUTHOR]

Compressed sensing (CS) is an innovative signal acquisition and reconstruction technology that has broken through the limit of the Nyquist sampling theory. It is widely employed to optimize the measurement processes in various applications. One of the core challenges of CS is the construction of a measurement matrix. However, traditional random measurement matrices are often impractical. Additionally, many existing deterministic binary measurement matrices fail to provide the required flexibility for practical applications. In this study, inspired by the observation that pseudo-random sequences share similar properties with random sequences, we constructed a deterministic sparse measurement matrix with a flexible measurement number based on an pseudo-random sequence—the Legendre sequence. Empirical analysis of the phase transition and an assessment of the practical features of the proposed measurement matrix were conducted. We validated the effectiveness of the proposed measurement matrix on randomly synthesized signals and images. The results of our simulations reveal that our proposed measurement matrix performs better than several other measurement matrices, particularly in terms of accuracy and efficiency. [ABSTRACT FROM AUTHOR]

Recent studies show that there is a universal thermodynamic behavior in crystalline solids: the heat capacity is dependent on both of the temperature and thermal expansion (or volume). In glasses (or disordered materials), the heat capacity jump at glass transition is a typical feature, and is an important unsolved problem in solid state physics. There is not a quantitative interpretation for the volume effect on the heat capacity jump at glass transition at present. In this paper, we study the volume effect on the thermal behaviors in the typical Pd-based glass-forming alloy, and give an accurate interpretation between the change of the volume and the temperature dependent thermal properties. The crystalline and its disordered materials have same model parameters and same volume effect. Phase transition can be classified only by the corresponding relation between the volume and temperature. And the glass transition, a volume-induced thermal behavior, is a special phase transition between the classical first order and second order phase transitions. The thermal properties in materials with different states are well explained by the unified heat capacity model when the volume effect is considered, which shows that there a general thermodynamic rule in materials. [ABSTRACT FROM AUTHOR]

We have investigated the thermodynamic property modification of ammonia borane via nanoconfinement. Two different mesoporous silica scaffolds, SBA-15 and MCM-41, were used to confine ammonia borane. Using in situ Raman spectroscopy, we examined how pore size influences the phase transition temperature from tetragonal (I4mm) to orthorhombic (Pmn21) for ammonia borane. In bulk ammonia borane, the phase transition occurs at around 217 K; however, confinement in SBA-15 (with ~8 nm pore sizes) reduces this temperature to approximately 195 K, while confinement in MCM-41 (with pore sizes of 2.1–2.7 nm) further lowers it to below 90 K. This suppression of the phase transition as a function of pore size has not been previously studied using Raman spectroscopy. The stability of the I4mm phase at a much lower temperature can be interpreted by incorporating the surface energy terms to the overall free energy of the system in a simple thermodynamic model, which leads to a significant increase in the surface energy when transitioning from the tetragonal phase to the orthorhombic phase. [ABSTRACT FROM AUTHOR]

Thermal management presents a significant challenge in electric design, particularly in densely packed electronic systems. This study proposes a theoretical model for radiative bionic skin that emulates human skin, enabling the self-adaptive modulation of the thermal exhaustion rate to maintain homeostasis for objects covered by the skin in fluctuating thermal environments. The proposed artificial skin consists of phase change material (VO2) nanoparticles embedded in a low-loss matrix situated on a metallic substrate with a minimal thickness of several micrometers. The findings from our theoretical analyses indicate that substantial alterations in thermal radiation power around the phase transition temperature of 340 K enable a silicone substrate to sustain a relatively stable temperature, with variations confined to ±6 K, despite external heat fluxes ranging from 150 to 450 W/m2. Furthermore, to improve the spectral resemblance to natural skin, a plasmonic surface composed of self-assembled silver nanocubes is incorporated, allowing for modifications to the visible light properties of the bionic skin while maintaining its infrared characteristics. This theoretical investigation offers a cost-effective and conformal approach to the design of ultra-compact, fully passive, and versatile thermal management solutions for robotic systems and related technologies. [ABSTRACT FROM AUTHOR]

This study reports the reversible solubility switching of a polymer triggered by non‐phototoxic visible light. A photochromic polymerizable azobenzene monomer with four methoxy groups at the ortho‐position (mAzoA) was synthesized, exhibiting reversible photoisomerization between trans‐ and cis‐states using green (546 nm) and blue light (436 nm). Free radical copolymerization of hydrophilic dimethylacrylamide (DMAAm) with mAzoA produced a light‐responsive random copolymer (P(mAzoA‐r‐DMAAm)) that shows a reversible photochromic reaction to visible light. Optimizing mAzoA content resulted in P(mAzoA10.7‐r‐DMAAm)3.0 kDa exhibiting LCST‐type phase separation in PBS (pH 7.4) with trans‐ and cis‐states at 39.2 °C and 32.9 °C, respectively. The bistable temperature range of 6.3 °C covers 37 °C, suitable for mammalian cell culture. Reversible solubility changes were demonstrated under alternating green and blue light at 37 °C. 1H NMR indicated significant retardation of thermal relaxation from cis‐ to trans‐states, preventing undesired thermal mechanical degradation. Madin Darby Canine Kidney (MDCK) cells adhered to the P(mAzoA‐r‐DMAAm) hydrogel, confirming its non‐cytotoxicity and potential for biocompatible interfaces. This principle is useful for developing hydrogels that can reversibly stimulate cells mechanically or chemically in response to visible light. [ABSTRACT FROM AUTHOR]