Phase Transition Research Articles

Phase transitions, critical behavior and microstructure of the FRW universe in the framework of higher order GUP

Phase transitions, critical behavior and microstructure of the FRW universe in the framework of higher order GUP

Liquid crystal phase behavior of oxalated cellulose nanocrystal and optical films with controllable structural color induced by centripetal force

Cellulose nanocrystal (CNC) is a sustainable bio-nanomaterial. The distinctive left-handed polarization properties render cellulose nanocrystal a promising candidate for optical film. Due to eco-friendliness, reliability, mildness and simplicity, the oxalate hydrolysis method stands out among various preparation methods for CNC. This study delved into the liquid crystal phase behavior of oxalated cellulose nanocrystal derived from pulp, and discovered the influences of CNC concentration and pH on suspension stability and phase transition, and evaluated its optical properties. The results demonstrated that oxalated CNC presented two different liquid crystal phases, the nematic phase and the cholesteric phase. The stability mechanism of CNC suspension and the regulatory principle of the liquid crystal phase transition were revealed. A novel CNC film-forming technology, the multilayer spin-coating technique, was developed for cellulose nanocrystal optical films. Driven by centrifugal force, cellulose nanocrystals were induced to self-assembly and formed the optical film with circular dichroism and structural color. This simple and efficient film-forming technology promised rapid processing (1 h) and controllable film structure and optical properties compared to traditional technologies. This work provided a theoretical understanding and practical prospects for integrating oxalated cellulose nanocrystal into sustainable advanced optical film materials.

Antidehydration and Stable Mechanical Properties during the Phase Transition of the PNIPAM-Based Hydrogel for Body-Temperature-Monitoring Sensors.

Poly(N-isopropylacrylamide) (PNIPAM) enhances the reversibility and responsiveness of wearable temperature-sensitive devices. However, an open question is whether and how the hydrogel design can prevent adhesive performance loss caused by phase-transition-induced dehydration and unstable mechanical properties between devices and human skin and reduce interfacial failure. Herein, a gelatin-mesh scaffold-based hydrogel (NAGP-Gel) is constructed to inhibit dehydration and volume change, leading to stable mechanical properties, superior adhesiveness, and thermal sensing sensitivity during the phase transition. NAGP-Gel enhances the polymer chains-water interaction and weakens the degree of aggregation of polymer chains-chains, improving antidehydration properties under 45 °C conditions that are higher than the lower critical solution temperature (LCST; i.e., ∼32 °C). The mesh scaffold greatly restricts the phase-transition-induced polymer chain movement and maintains the mechanical performance. In a 60 °C environment, the maximum water loss and volume retention ratio of NAGP-Gel are only 3.58% and 97.3%, respectively. Additionally, NAGP-Gel serves as a temperature sensor, producing a stable thermal-electrical signal within the LCST range. It also can be assembled into an electronic device enabling the transmission of information and recognition of sign language via Morse code. This work broadens the application of PNIPAM in constructing intelligent hydrogels and opens the door to exploring emerging hydrogels for temperature-monitoring applications.

A Comprehensive Modeling on MoS2 Interface and Defect Engineering in CZTS Thin Film Solar Cells

This work uses the SCAPS-1D modeling program to examine the effects of faults in the molybdenum Disulfide (MoS2) layer and the MoS2 interface on the electrical performance of CZTS solar cells. To get an ideal energy gap (Eg) of 1.3 eV and a carrier concentration (CC) of 1014 cm⁻³, the research attempts to optimize the CZTS absorber layer. By maintaining a consistent doping level with 1016 cm-3 ≤ CC and an Eg within 1.6 eV < Eg ≤ 1.8 eV for the MoS2 film, the work also investigates the possibility of increased efficiency in CZTS/MoS2 devices. The study results indicate that open circuit voltage (VOC) and Efficiency (Eta-η) parameters are improved by a p-type MoS2 interface, indicating a promising development for CZTS solar systems. Nonetheless, n-type MoS2 suggests a compromise with a reduction in the fill factor. The study emphasizes the stability benefits of a p-type MoS2 interface as well as the importance of surface recombination velocity. The study also considers phase transitions that occur during the manufacture of devices, highlighting the intrinsic n-type character of MoS2 and the importance of experimental methods in CZTS device optimization. After analyzing the effects of defects on carrier density, depletion width, and quantum efficiency, the study concludes that enhancing the performance of CZTS solar cells requires an acceptor-type interface with p-type MoS2. With recombination resistances of 443.92 Ω cm2, 1530.33 Ω cm2, 81.54 Ω cm2, and 93.82 Ω cm2, the SCAPS model shows zero series resistance at a particular site for the fundamental, optimized design using n-MoS2 and p-MoS2. In the end, the work sheds light on the possibilities for additional experimental studies to advance the technology of CZTS solar cells.

The TCONS_00046732/chi-miR-135b-5p/PRLR regulatory axis promotes endometrial epithelial cells growth through the PI3K-Akt signaling pathway

Non-coding RNAs are considered key regulatory factors in biological and reproductive physiological processes in mammals. However, the molecular functions of long noncoding RNAs (lncRNAs) in regulating dynamic uterine development and reproductive capacity during sexual maturation remain unclear. This study analyzed the expression characteristics and molecular functions of lncRNAs in uterine tissues from 20 goats at four specific time points during sexual maturation: day 1 after birth (D1), 2 months (M2), 4 months (M4), and 6 months (M6), finding that stage-specific DE lncRNAs may regulate cell proliferation, apoptosis, hormone secretion, metabolism, and immune response through multiple action modes. Within the lncRNA-miRNA-mRNA network, a novel lncRNA, TCONS_00046732, associated with uterine development, exhibited significantly higher expression during sexual maturity compared to the prepubertal stage, correlating positively with PRLR and negatively with chi-miR-135b-5p. FISH and IF analyses revealed significant co-localization and distinct expression patterns of TCONS_00046732, chi-miR-135b-5p, and PRLR in the endometrial epithelium. Further experiments confirmed that TCONS_00046732 competitively binds to chi-miR-135b-5p to upregulate PRLR, thereby activating the PI3K-Akt signaling pathway, promoting primary endometrial epithelial cell proliferation, G1-to-S phase transition, and inhibiting apoptosis. These findings enhance our understanding of uterine molecular regulation and provide key insights into the molecular basis of goat sexual development.

Atomic-scale material removal and deformation mechanism in nanoscratching GaN

Gallium nitride (GaN) is an important third-generation semiconductor material. However, due to its high hardness, high brittleness and anisotropy, the material removal efficiency of GaN during ultraprecision machining is low, and subsurface damage easily occurs. In order to achieve high-efficiency and low-damage ultra-precision machining, the model of double nanoscratches is innovatively utilized to investigate the mechanical behavioral of GaN at the atomic scale. Specifically, double nanoscratches experiments and corresponding molecular dynamics (MD) simulations were carried out on GaN (0001) crystal plane along the [101¯0] and [12¯10] crystal directions to reveal the material removal, deformation and subsurface damage mechanisms of GaN under anisotropic conditions. The results show that the plastic removal of GaN can be realized by setting loading force and scratch spacing. Scratching along the [12¯10] crystal direction has a greater ductile-brittle transition load force than the [101¯0] crystal direction. MD analysis shows that the downward-extending prismatic slip produced by scratching along the [101¯0] crystal direction is the cause of crack extension to the subsurface during the experiment. As the load force increases, the surface cracks of the double scratches expand and intersect, inducing streak-like brittle fracture. The significant increase in the lateral force of the second scratch is the main reason for the brittle fracture in the double scratch experiment. After the double nanoscratches experiment, the damage presented on the GaN subsurface mainly includes atomic scale damage such as amorphization, stacked laminations, polycrystalline nanoscratch, and phase transition. The Stacking fault bands around the damage zone inhibit the damage extension. The second scratch generates a large number of dislocations in the overlap zone and attenuates the subsurface amorphization under the influence of dislocation strengthening effect.

Microstructure evolution of CdZnTe crystals irradiated by heavy ions

Consideration of irradiation effects is important for in-orbit operation and radiation protection in aerospace applications. The configuration of irradiation defects and their impact on deteriorating the carrier transport properties of CZT crystals need to be clarified. In this study, the microdefect evolution mechanism of CdZnTe (CZT) crystals under 10 MeV Chlorine (Cl) ion irradiation at flux of 1×1010∼1×1012 n·cm-2 are investigated. The stacking faults first appear in the CZT crystal at 4.5×10-4 displacement per atom (dpa), which are categorized into slip-type, gap-type and vacancy-type. In order to hinder the further expansion of stacking fault, S-shaped stacking fault dipole appears. When the dpa reaches 4.5×10-2, the local phase transition occurs in the damage zone to form CuPt-A ordered phase with ZnTe/CdTe periodic arrangement because the fluctuation in local composition and strain caused by cascade collisions. The deterioration of electric field distribution and charge collection caused by irradiation damage layer leads to the decrease of γ-ray detection ability. The energy resolution (ER) of the CZT detector for γ-ray can be maintained at 30.6% when the ion flux accumulates to 1×1012 n·cm-2, revealing high irradiation hardness. Consequently, these findings provide a theoretical basis for the radiation damage recovery of CZT detectors, further demonstrating that CZT crystals are the most competitive new generation of room-temperature nuclear radiation detection materials, and can provide radiation protection strategies for similar compound semiconductor materials.

Solvent Induced Crystallization and Phase Transition of Syndiotactic Polymethoxystyrene Investigated Using In Situ Wide Angle X-ray Diffraction

Solvent Induced Crystallization and Phase Transition of Syndiotactic Polymethoxystyrene Investigated Using In Situ Wide Angle X-ray Diffraction

Crystal Modulation of Mn-Based Layered Oxide toward Long-Enduring Anionic Redox with Fast Kinetics for Sodium-Ion Batteries.

Mn-based layered oxide cathodes for sodium-ion batteries with anionic redox reactions hold great potential for energy storage applications due to their ultra-high capacity and cost effectiveness. However, achieving high capacity requires overcoming challenges such as oxygen-redox failure, sluggish kinetics, and structural degradation. Herein, we employ an innovative crystal modulation strategy, using Mn-based Na0.72Li0.24Mn0.76O2 as a representative cathode material, which shows that the highly exposed {010} active facets enable an enhanced rate capability (119.6 mAh g-1 at 10C) with fast kinetics. Meanwhile, the reinforced Mn-O bond inhibits excessive oxidation of lattice oxygen and O-O cohesion loss, stabilizing and maintaining a long-enduring reversible oxygen-redox activity (100% high capacity retention after 100 cycles at 0.5C and 84.28% retention after 300 cycles at 5C). Time-resolved operando two-dimensional X-ray diffraction reveals the robust structural stability, zero-strain behavior, and suppressed phase transition with ultra-low volume variation during cycling at different rates (0.1C: 1.75%, 1C: 0.31%, 5C: 0.04%). Additionally, the full cell coupled with hard carbon achieves a high energy density of approximately 211 Wh kg-1 with superior performance. This work highlights the significance of crystal modulation and presents a universal approach in developing Mn-based oxide cathodes with stable anionic redox for high-performance sodium-ion batteries.

KH571 construct interfacial molecular bridge in calcium silicate/TMPTA/HDDA scaffolds for improving mechanical properties and photopolymerization

Digital Light Processing (DLP) offers the potential for personalized bone implants. Within this method, the interfacial bonding capacity of inorganic/organic materials and the solid-phase content of the slurry emerge as primary factors influencing scaffolds mechanical properties. In this research, KH571 was applied to establish an interfacial “molecular bridge”, adopting in situ coupling technology to forge stable covalent bonds between calcium silicate (CSi) and KH571. Surface photografting and photopolymerization techniques were then utilized to construct a photo-crosslinked network by CSi-KH571-TMPTA/HDDA slurry, thereby transforming the weak physical connections at the interface into strong chemical bonds. Consequently, the curing capacity and mechanical properties of the scaffolds were enhanced. Further control grain size, crystal phase transition, and shrinkage of CSi-KH571 scaffolds was achieved through post-treatment sintering processes, culminating in the fabrication of scaffolds with high β-CSi content. In this paper, optimal process parameters were selected concerning grafting rate, chemical composition, microscopic morphology, crystalline transformation, dimensional accuracy, mechanical properties, biodegradation and biocompatibility of CSi-KH571. The elastic modulus and compressive properties of CSi25-55 scaffolds exhibited a notable improvement of 29.71 % and 59.30 %, respectively, compared to CSi-50 scaffolds. By regulating the phase composition of CSi, CSi25-55 scaffolds were designed to possess a controllable degradation. In vitro cell culture experiments validated its excellent biocompatibility and promoted the proliferation and differentiation of bone cells as well as the deposition of bone matrix. Herein, a novel and sustainable approach has been promoted for enhancing the interfacial bonding capacity of inorganic/organic materials and the solid-phase content of printing slurry, which lays the foundation for the printing of high-resolution degradable bioceramic scaffolds.

Exploring Experimental Tests concerning Liquid Hydrogen Releases

In recent years, the adoption of liquid hydrogen (LH2) has increased significantly in industrial and transport applications, driven by its low carbon footprint, thereby aiding the fight against global warming. Additionally, its high volumetric energy density, compared to gaseous or compressed hydrogen, enhances hydrogen storage capabilities. However, safety remains a major concern due to its physical-chemical properties and inherent hazardous characteristics, especially in the event of spillage scenarios. Therefore, to better understand the consequences of LH2 releases onto or into water, large-scale experimental tests were conducted by Bundesanstalt für Materialforschung und -prüfung (BAM) within the Safe Hydrogen Fuel Handling and Use for Efficient Implementation (SH2IFT) project at the Test Site Technical Safety of BAM, comprising 75 single spill events at varied release rates and orientations. While the rapid phase transition (RPT) phenomenon was not observed, self-ignition of the hydrogen-air cloud occurred, accompanied by blast wave overpressure and heat radiation, without a discernible ignition source. These findings emphasize the need for further investigation into LH2 safety. Leveraging experimental data for real-world applications provides insights into safe LH2 infrastructure implementation, laying foundational knowledge for addressing safety challenges and advancing LH2 technology.

Correlating the microstructure of titanium hydride with its hydrogenation conditions via thermodynamics and kinetics

Titanium hydride is widely considered as an important hydrogen storage material due to its high capacity, stability and low cost. The microstructure of titanium hydride, which is usually induced by the hydrogenation of titanium, strongly influences its storage performance. However, the relationship between the hydrogenation conditions and the derived microstructure of titanium hydride is still unclear, limiting the development of its structure design strategy. In this work, the microstructure of titanium hydride is correlated with its hydrogenation conditions through the thermodynamics and kinetics. By evaluating the effect of the hydrogenation temperature, pressure and cooling rate, three classes of the hydrogenation processes were clarified as kinetic-limited, continuous and stepwise. Besides, according to the SEM and FIB-STEM results, these different processes are confirmed to greatly vary the bulk microstructure. It is concluded that a fast and continuous transition induces a broken bulk morphology, while a stepwise process leads to a larger bulk grain size. In summary, this study presents a framework for designing titanium hydride structures by modifying phase transition processes through careful adjustment of hydrogenation parameters, namely, a condition-process-structure relationship. This relationship offers crucial guidance in managing the grain refinement or coarsening of hydrides within hydrogen storage components and metallurgical applications.

What will be the Euclidean dimension of an Ising ferromagnetic cubic shell?

The equilibrium and nonequilibrium properties of an Ising ferromagnetic cubic shell have been extensively studied by Monte Carlo simulation using Metropolis single spin flip algorithm. Although, geometrically the Euclidean dimension of the cubical shell is three, interestingly, the Ising ferromagnetic cubic shell undergoes ferromagnetic phase transition at a temperature which is very close to that for two-dimensional Ising ferromagnet. Surprisingly, the Ising ferromagnetic cubic shell shows a strange (neither exponential nor stretched exponential) kind of relaxation behaviour, instead of exponential relaxation as usually observed in the two dimensional Ising ferromagnet. The metastable lifetime of a ferromagnetic Ising cubical shell is studied as a function of the applied magnetic field. Here also, the cubic shell behaves more likely a two-dimensional object as found from statistical analysis and comparison with Becker-Döring prediction of classical nucleation theory.

Wilson Lines in the Abelian Lattice Higgs Model

AbstractLattice gauge theories are lattice approximations of the Yang–Mills theory in physics. The abelian lattice Higgs model is one of the simplest examples of a lattice gauge theory interacting with an external field. In a previous paper (Forsström et al. in Math Phys 4(2):257–329, 2023), we calculated the leading order term of the expected value of Wilson loop observables in the low-temperature regime of the abelian lattice Higgs model on $${\mathbb {Z}}^4,$$ Z 4 , with structure group $$G = {\mathbb {Z}}_n$$ G = Z n for some $$n \ge 2.$$ n ≥ 2 . In the absence of a Higgs field, these are important observables since they exhibit a phase transition which can be interpreted as distinguishing between regions with and without quark confinement. However, in the presence of a Higgs field, this is no longer the case, and a more relevant family of observables are so-called open Wilson lines. In this paper, we extend and refine the ideas introduced in Forsström et al. (Math Phys 4(2):257–329, 2023) to calculate the leading order term of the expected value of the more general Wilson line observables. Using our main result, we then calculate the leading order term of several natural ratios of expected values and confirm the behavior predicted by physicists.

Expansion of Landau theory with Magnetic Susceptibility and Heat Capacity

Abstract. Landau theory employs free energy to depict the work potential of molecules and utilizes order parameters to signify the degree of molecular organization. By applying a Taylor expansion of the free energy with respect to the order parameter in the vicinity of a phase transition, the theory elucidates how molecular arrangements can influence the system's energy. The universality of Landau theory stems from the order parameter within the framework of free energy expansion. The application of critical exponents exemplifies the universality of Landau theory, showcasing the properties of materials that share the same dimensionality and similar correlation lengths. This article aims to derive formulas and discuss practical applications of Landau theory, such as analyzing the heat capacity and magnetic susceptibility of materials across a range of temperatures.

Protracted Kondo coherence with dilute carrier density in cerium based nickel pnictides

Nozières' exhaustion theory argues that the temperature for coherently screening of all local moments in Kondo lattice could be much lower than the temperature of single moment screening in case of insufficient conduction electrons. Experiments indicate that cerium based nickel pnictides CeNi2−δAs2(δ≈0.28) is an ideal material to exam such protracted Kondo screening. Using density functional theory plus dynamical mean-field theory, we found CeNi2As2 presents a transition from the local moment states to the coherent Kondo screening states under compression, accompanied by topological changes of the Fermi surface. Similar phase transition could be driven by chemical pressure via the isovalence As→P substitution. The derived coherent Kondo temperature Tcoh is much lower than the single-impurity Kondo temperature TK due to the diluted Ni-3d conduction electrons, indicating the protraction of Kondo screening in crystal. In contrast to structurally analogous layered iron pnictides, the electronic structures of the present systems show strong three-dimensionality.

LC3 cementitious binder incorporating microencapsulated phase change materials for self-defrosting traffic surfaces

Exposed surfaces of bridge decks, viaducts and pavements incur ice formation and accumulation of snow in cold seasons, which threatens traffic safety. Mitigating this problem using traditional methods such as deicing salts have caused ecosystem damage and inflicted substantial reinforcement corrosion and surface scaling to bridge decks and pavements, thus compromising their service life and causing colossal economic loss. This paper presents an alternative solution to overcome this problem through the development of a sustainable LC3 cementitious material incorporating micro-encapsulated phase change material (MEPCM) with low phase transition temperature to delay the surface temperature drop and mitigate snow accumulation and ice formation. MEPCM was incorporated in the cementitious matrix at 0 %, 10 % and 20 % by binder mass. Paste and mortar mixtures were prepared to investigate the microstructural, mechanical, physical, and thermal properties. Test results showed that incorporating MEPCM in the LC3 matrix achieved adequate compressive strength. Thermal simulations and visual observations conducted on mortar samples in the laboratory and outdoor exposure showed that MEPCM can effectively regulate the surface temperature of the LC3 matrix and mitigate temperature drops as well as snow accumulation. Analysis of temperature data in the 2023–2024 winter season of Hamilton, Ontario, Canada indicated that the MEPCM incorporated in mortar samples could effectively regulate 40 % of the total days considered and mitigate surface ice formation and snow accumulation, which provides both economic and environmental benefits.

Development of novel multifunctional phase change microcapsules for improving thermal comfort and radiation properties

Microencapsulated phase change materials (MPCMs) have gained widespread application in energy-efficient buildings, aiming to improve thermal comfort and reduce energy consumption. To enhance the engineering feasibility of MPCMs, researchers are now focusing on developing MPCMs with multifunctional properties, beyond single thermal storage functionality. In this study, we proposed a novel and straightforward approach to fabricate multifunctional MPCMs with BaCO3 as shell and a core composed of binary phase change materials (PCMs) and lipophilic-modified graphite (MG) via self-assembly method. The incorporation of BaCO3 shell provides MPCMs with additional resistance to ionizing radiation pollution due to the high atomic number element Ba. Additionally, the incorporation of MG into PCMs enhances its temperature sensitivity. The thermal analysis indicates that the binary PCMs’ composition in MPCMs results in two phase transition temperatures at 3.3 °C and 26.4 °C, making them capable of thermal storage in line with comfortable residential temperatures across different seasons. Furthermore, MPCMs were introduced into cement paste (CPM) and used to construct cement chambers. Adding 10 wt% MPCMs in the CPM chambers placed outdoors in Wuhan (from June 7th to June 9th) led to a 23.8 % decrease in temperature fluctuations compared to the reference sample. Radiation shielding results indicated that the linear attenuation coefficient (μ) of CPM increased by 58.7 %, due to enhanced incoherent scattering and photoelectric effects between high atomic number elements and photons. Additionally, XCOM simulations predicted a strong correlation between MPCM content and μ values, with particularly high accuracy at low photon energies. Overall, the multifunctional MPCMs developed in this study not only offers a new route for reducing residential energy consumption and shielding ionizing pollution, but also broadens the applicability of traditional PCMs in the building and other fields.

High-Resolution Spectroscopy of the Intermediate Impurity States near a Quantum Phase Transition.

The intermediate behavior near a quantum phase transition is crucial for understanding the quantum criticality of various competing phases and their separate origins, yet it remains unexplored for the multiple Yu-Shiba-Rusinov (YSR) states. Here, we investigated the detailed spectroscopic change of the exchange-coupling-dependent YSR states near a quantum phase transition. The initially developed one pair of YSR states, induced by the Fe vacancy in monolayer Fe(Te,Se) superconductor, are clearly resolved with high resolution showing an evolution into two pairs of YSR peaks yet with dichotomy in their spectral features as they enter the quantum phase transition region. Spectral-weight analysis suggests that the double YSR pairs occur as a result of field splitting by the magnetic anisotropy. Our findings unveil the intermediate region of a quantum phase transition with a magnetic anisotropy-induced splitting of the YSR resonance, and highlight a prospect for developing functional electronics based on the flexibly controllable multiple quantum states.

Crystal Modulation of Mn‐Based Layered Oxide toward Long‐Enduring Anionic Redox with Fast Kinetics for Sodium‐Ion Batteries

Mn‐based layered oxide cathodes for sodium‐ion batteries with anionic redox reactions hold great potential for energy storage applications due to their ultra‐high capacity and cost effectiveness. However, achieving high capacity requires overcoming challenges such as oxygen‐redox failure, sluggish kinetics, and structural degradation. Herein, we employ an innovative crystal modulation strategy, using Mn‐based Na0.72Li0.24Mn0.76O2 as a representative cathode material, which shows that the highly exposed {010} active facets enable an enhanced rate capability (119.6 mAh g−1 at 10C) with fast kinetics. Meanwhile, the reinforced Mn–O bond inhibits excessive oxidation of lattice oxygen and O–O cohesion loss, stabilizing and maintaining a long‐enduring reversible oxygen‐redox activity (100% high capacity retention after 100 cycles at 0.5C and 84.28% retention after 300 cycles at 5C). Time‐resolved operando two‐dimensional X‐ray diffraction reveals the robust structural stability, zero‐strain behavior, and suppressed phase transition with ultra‐low volume variation during cycling at different rates (0.1C: 1.75%, 1C: 0.31%, 5C: 0.04%). Additionally, the full cell coupled with hard carbon achieves a high energy density of approximately 211 Wh kg−1 with superior performance. This work highlights the significance of crystal modulation and presents a universal approach in developing Mn‐based oxide cathodes with stable anionic redox for high‐performance sodium‐ion batteries.