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Electron doped Ca0.85Nd0.15MnO3 (CNMO) compound was synthesized by the solid state reaction process. Rietveld analysis of X-ray diffraction data confirms that the Electron doped CNMO compound crystallizes to orthorhombic perovskite structure. Here we have reported the order of magnetic phase transition and the nature of magnetic interaction of CNMO sample. The positive value of the Landau coefficient b(TC) signifies that the sample undergoes 2nd order phase transition. The calculated values of critical exponents β, γ and δ show large deviation from existing theoretical models such as 3D mean field, tri-critical mean field, 3D Ising and 3D Heisenberg models. This indicates that the CNMO compound exhibits non conventional magnetic interaction. [ABSTRACT FROM AUTHOR]

Electron doped Ca0.85Nd0.15MnO3 (CNMO) compound was synthesized by the solid state reaction process. Rietveld analysis of X-ray diffraction data confirms that the Electron doped CNMO compound crystallizes to orthorhombic perovskite structure. Here we have reported the order of magnetic phase transition and the nature of magnetic interaction of CNMO sample. The positive value of the Landau coefficient b(TC) signifies that the sample undergoes 2nd order phase transition. The calculated values of critical exponents β, γ and δ show large deviation from existing theoretical models such as 3D mean field, tri-critical mean field, 3D Ising and 3D Heisenberg models. This indicates that the CNMO compound exhibits non conventional magnetic interaction. [ABSTRACT FROM AUTHOR]

We have investigated the structural phase transition and higher order elastic constants of plutonium chalcogenides (PuX, X=S,Se,Te) using three body interaction potential (TBIP). The three body interaction arises from the electron-shell deformation when the nearest –neighbor ions overlap. This method has been found quite satisfactory in the case of other alkaline earth chalcogenides. The calculated equation of states of plutonium chalcogenides have been compared with high pressure X-ray diffraction data. The theoretically predicted phase transition pressure and other structural properties for these compounds agree reasonably well with the measured values. We have also reported the second and third order elastic constants and second order pressure derivatives. The variation of second order elastic constants (SOEC) is also presented. [ABSTRACT FROM AUTHOR]

High pressure structural and elastic properties of neptunium arsenide (NpAs) have been studied using three body interaction potential (TBIP). The three body interaction arises from the electron-shell deformation when the nearest –neighbor ions overlap. The equation of state of NpAs has been calculated and compared with high pressure X-ray diffraction data. The theoretically predicted phase transition pressure and other structural properties agree reasonably well with the measured values. The second and third order elastic constants, second order pressure derivatives and variation of second order elastic constants (SOEC) with pressure is also presented. [ABSTRACT FROM AUTHOR]

Vanadium substituted TiO2 samples are prepared by modified sol-gel process. X-ray diffraction (XRD) pattern and Raman spectra for all the samples reveal pure tetragonal phases of TiO2. Rutile percentage calculated from XRD pattern and Raman spectra follow a similar trend and signify that vanadium substitution promotes phase transformation from anatase to rutile. Due to aliovalent V substitution, donor levels are formed in the bandgap which is responsible for bandgap reduction. [ABSTRACT FROM AUTHOR]

Vanadium substituted TiO2 samples are prepared by modified sol-gel process. X-ray diffraction (XRD) pattern and Raman spectra for all the samples reveal pure tetragonal phases of TiO2. Rutile percentage calculated from XRD pattern and Raman spectra follow a similar trend and signify that vanadium substitution promotes phase transformation from anatase to rutile. Due to aliovalent V substitution, donor levels are formed in the bandgap which is responsible for bandgap reduction. [ABSTRACT FROM AUTHOR]

In this paper we investigate the problem of phase transition for Ising model on a semi-infinite Cayley tree of third order with inhomogeneous left, middle and right parameters describing the strength of the interactions between left, middle and right nearest-neighbors respectively. We produce a recurrent equation that describes a limit behavior of the sequence conditional Gibbs measures and prove that if at least two of the parameters are positive one can reach phase transition. [ABSTRACT FROM AUTHOR]

This study is a molecular dynamics investigation of phase change phenomena i.e. boiling of thin liquid films subjected to rapid linear heating at the boundary. The purpose of this study is to understand the phase change heat transfer phenomena at nano scale level. In the simulation, a thin film of liquid argon over a platinum surface has been considered. The simulation domain herein is a three-phase system consisting of liquid and vapor argon atoms placed over a platinum wall. Initially the whole system is brought to an equilibrium state at 90 K and then the temperature of the bottom wall is increased to a higher temperature (250K) within a finite time interval. Four different liquid argon film thicknesses have been considered (3 nm, 4 nm, 5 nm and 6 nm) in this study. The boundary heating rate (40x109 K/s) is kept constant in all these cases. Variation in system temperature, pressure, net evaporation number, spatial number density of the argon region with time for different film thickness have been demonstrated and analyzed. The present study indicates that the pattern of phase transition may be significantly different (i.e. evaporation or explosive boiling) depending on the liquid film thickness. Among the four cases considered in the present study, explosive boiling has been observed only for the liquid films of 5nm and 6nm thickness, while for the other cases, evaporation take place. [ABSTRACT FROM AUTHOR]

This study focuses on the occurrence of bubble nucleation in a liquid confined in a nano scale confinement and subjected to rapid cooling at one of its wall. Due to the very small size scale of the present problem, we adopt the molecular dynamics (MD) approach. The liquid (Argon) is confined within two solid (Platinum) walls. The temperature of the upper wall of the confinement is maintained at 90 K while the lower wall is being cooled rapidly to 50 K from initial equilibrium temperature of 90 K within 0.1 ns. This results in the nucleation and formation of nanobubbles in the liquid. The pattern of bubble nucleation has been studied for three different conditions of solid-liquid interfacial wettability such as hydrophilic, hydrophobic and neutral. Behavior of bubble nucleation is significantly different in the three case of solid-liquid interfacial wettability. In case of the hydrophobic confinement (weakly adsorbing), the liquid cannot achieve deeper metastability; vapor layers appear immediately on the walls. In case of the neutral confinement (moderately adsorbing), bubble nucleation is promoted by the walls where the nucleation is heterogeneous. In case of the hydrophilic walls (strongly adsorbing) bubbles are developed inside the liquid; that is the nucleation process is homogeneous. The variation in bubble nucleation under different conditions of surface wettability has been studied by the analysis of number density distribution, spatial temperature distribution, spatial number density distribution and heat flux through the upper and lower walls of the confinement. The present study indicates that the variation of heat transfer efficiency due to different surface wettability has significant effect on the size, shape and location of bubble nucleation in case rapid cooling of liquid in nano confinement. [ABSTRACT FROM AUTHOR]

The peculiar nucleation behavior of low thermal conductivity polymer matrixes and the particular morphologies around fibers found in several composites, invalidate some assumptions invoked in the general description of the solidification kinetics of polycrystalline substances. The model of solidification universally adopted for polycrystalline substances, originally developed for metals, needs to be adapted also to account for large differences between polymers and fibers in thermoplastic composites. The extension of the classical phase transitions theory to fiber/polymer composites, in view of their specific thermal properties, allows to achieve reliable information on crystallization behavior and microstructure inside composites. [ABSTRACT FROM AUTHOR]

The Rheo-Raman Microscope combines rheology, Raman spectroscopy and polarization light microscopy and provides comprehensive insight into a material's bulk as well as micro structural properties under well defined and reproducible conditions such as temperature or shear profiles. The simultaneous acquisition with three independent analytical methods is advantageous for investigation of structural changes occurring for example in gelation, melting or crystallization. Details of this hyphenated instrumentation as well as selected results including temperature induced melting of a polymer emulsion and crystallization of a polymer melt are presented in this contribution. [ABSTRACT FROM AUTHOR]

In the present communication, we have computed static and dynamic properties (binding energy-E, bulk modulus-B and second moment- <ω2>) as well as first order pressure induced phase transition (FCC-BCC) using local form of pseudopotential for Calcium and Strontium. The form of pseudopotential used for the computation is directly extracted from Generalized Pseudopotential Theory (GPT) which contains three parameters (rc, rd and β). We have suggested a simple method using which pseudopotential is determined by single parameter (β). Our computed results for binding energy and bulk modulii are in excellent agreement with experimental findings and are better than other theoretical results. The present study confirms that s-d hybridization is accounted properly in the presently used pseudopotential and can be extended for the study of lattice mechanical properties of these metals. [ABSTRACT FROM AUTHOR]

Spin glass (SG) is a typical magnetic system with frozen random spin orientation at low temperatures. The system exhibits rich physical properties, such as infinite number of ground states, memory effect, and aging phenomena. There are two main ingredients considered to be pivotal for the existence of SG behavior, namely, frustration and randomness. For the canonical SG system, frustration is led by the presence of competing interaction between ferromagnetic (FM) and antiferromagnetic (AF) couplings. Previously, Bartolozzi et al. [Phys. Rev. B73, 224419 (2006)], reported the SG properties of the AF Ising spins on scale free network (SFN). It is a new type of SG, different from the canonical one which requires the presence of both FM and AF couplings. In this new system, frustration is purely caused by the topological factor and its randomness is related to the irregular connectvity. Recently, Surungan et. al. [Journal of Physics: Conference Series, 640, 012001 (2015)] reported SG bahavior of AF Heisenberg model on SFN. We further investigate this type of system by studying an AF Heisenberg model on rewired square lattices. We used Replica Exchange algorithm of Monte Carlo Method and calculated the SG order parameter to search for the existence of SG phase. [ABSTRACT FROM AUTHOR]

The phase diagram of two-color QCD with a chiral chemical potential is studied on the lattice. The focus is on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulations are carried out with dynamical staggered fermions without rooting. The dependence of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented. [ABSTRACT FROM AUTHOR]

The phase diagram of two-color QCD with a chiral chemical potential is studied on the lattice. The focus is on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulations are carried out with dynamical staggered fermions without rooting. The dependence of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented. [ABSTRACT FROM AUTHOR]

We consider an interaction of the nearest-neighbors and next nearest-neighbors for the mixed type p-adic λ-model with spin values {-1,+1} on a Cayley tree of order two. In the previous work we have proved the existence of the p-adic Gibbs measure for the model. In this work we have proved the existence of the phase transition occurs for the model. [ABSTRACT FROM AUTHOR]

In this paper, we consider the Potts model with competing interactions on the Cayley tree of order three. Also we assume the state space set of the Potts model as Φ = {1,2,3,4} while it has taken as Φ = {1,2,3} in the previous studies [3, 8, 9]. we construct the Gibbs measures corresponding to the model by using Markov random field method. We calculate the critical curve such that there is a phase transition for the model. We extend the results introduced in the references [3, 8]. [ABSTRACT FROM AUTHOR]

In the present paper, we have investigated the high-pressure structural phase transition of rare-earth antimonides (NdSb and DySb). We studied theoretically the structural properties of alloy of these compounds (NdSb and DySb) by using the three-body potential model with the effect of electronic polarizability (TBIPEP). These compounds exhibit first order crystallographic phase transition from NaCl (B1) to CsCl (B2) phase at 17.8 GPa and 22.6 GPa respectively. The study has been extended to mixed crystals and the effect of composition on transition pressure and volume change is investigated. The phase transition pressures and associated volume collapse obtained from present potential model (TBIPEP) show a good agreement with available experimental data. [ABSTRACT FROM AUTHOR]

The results of study the phenomenon, discovered by author (1971), of the phase transition of grain boundary by the formation of two-dimensional liquid or quasi-liquid films have been done. The described phenomena of the first order phase transition (two-dimensional melting) at temperatures 0.6 - 0.9 TS0 (of the solid state melting point) is a fundamental property of solid crystalline materials, which has allowed to revise radically scientific representations about a solid state of substance. Using the mathematical tools of the film thermodynamics it has been obtained the generalized equation of Clausius - Clapeyron type for two-dimensional phase transition. The generalized equation has been used for calculating grain boundary phase transition temperature TSf of any metal, which value lies in the range of (0.55...0.86) TS0. Based on these works conclusions the develop strategies for effective forming of coatings (by thermo-chemical processing) on surface layers of functional alloys and hard metals have been made. The short overview of the results of some graded alloys characterization has been done. [ABSTRACT FROM AUTHOR]

We discuss the thermodynamics of compressed baryonic matter with strangeness within non-relativistic meanfield models with effective interactions. The phase diagram of the full baryonic octet under strangeness equilibrium is built and discussed in connection with its relevance for core-collapse supernovae and neutron stars. A simplified framework corresponding to (n,p, A)(+e)-mixtures is employed in order to test the sensitivity of the existence of a phase transition on the (poorely constrained) interaction coupling constants and the compatibility between important hyperonic abundances and 2M⊙ neutron stars. [ABSTRACT FROM AUTHOR]

Laser surface boriding was carried out using boropak and TiB+amorphous boron coated Cp-Ti alloy with high power diode laser (HPDL). The effect of boron agents and laser processing parameters on the microstructure, crystallographic phase formations and hardness are investigated by optical microscopy, scanning electron microscopy, XRD and hardness testing. Super-hard coating with hardness in the range of 1000 to 3000 HV0.2 was created by laser alloying the boropak and TiB+amorphous boron coated Cp-Ti. It is due to the formation of TiB2, TiB and Ti3B4 composite layers. Laser boriding has resulted in 2500_m thick coating. [ABSTRACT FROM AUTHOR]

The phase transition induced by Severe Plastic Deformation (SPD) was confirmed in metastable AISI type 304L austenitic stainless steel (SS). SPD via cryo-rolling in liquid nitrogen (L-N2) temperature is the adopted route for correlating the phase transition and corrosion resistance. The thickness of the annealed AISI type 304L SS at 1050°C sheet was reduced step by step from 15% to 50% of its initial thickness. The phase changes and phase transformation are qualitatively analyzed by X-Ray Diffraction (XRD) method. During the process, the XRD of each Cryo-Rolled and annealed sample was analyzed and different phases and phase transitions are measured. The investigated AISI type 304L SS by SPD reveals a microstructure of γ'-austenite; α-marternsite ε-martensite formation depending on the percentage of cryo-rolling. The Vickers hardness (HV) of the samples is also measured. The corrosion rate of the annealed sheet and cryo rolled sample was estimated in boiling nitric acid as per ASTM A-262 practice-C test. [ABSTRACT FROM AUTHOR]

R.1-xSrxMnO3 (R-Rare earth elements such as La, Pr, Sm and Nd) perovskite materials were prepared employing solid state reaction technique. On-line measurement of ultrasonic longitudinal velocity was carried out on the prepared perovskites over a wide range of temperature at a fundamental frequency of 5 MHz employing through transmission method. The phase transition temperature is explored based on the variation in observed anomaly in ultrasonic velocity. The obtained transition width and height at Curie temperature (i.e., transition from ferro to para magnetic phase) in the measured ultrasonic velocity were used to explore the physiochemical properties of the perovskites. The transition width and height of anomalous peak in measured ultrasonic velocity are also correlated with the ionic radius of the trivalent element. The results reveal that an increase in ionic radius of the trivalent elements leads to a decrease in double exchange interaction. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is an excellent ceramic material which exists in several polytypes. In this work, we obtained the structural properties of the ambient Zinc-Blende and high pressure Rock-Salt structures of SiC from density functional theory (DFT). We studied the structural phase transition occurring under compression using Debye Gruneisen theory based on scaled binding energy model. We observed excellent agreement of our predicted 300 K isotherm for SiC with experimental data. [ABSTRACT FROM AUTHOR]

Modeling of fluids with liquid to gas phase transition has become important for understanding many environmental or industrial processes. Such simulations need new techniques, because traditional solvers are often limited. The Lattice Boltzmann Model (LBM) allows simulate complex fluids, because its mesoscopic nature gives possibility to incorporate additional physics in comparison to usual methods. In this work, an improved lattice Boltzmann model for phase transition flow will be introduced. First, the state of art for Shan & Chen [1] [2] (SC) type of LBM will be reminded. Then, link to real thermodynamics will be established with Maxwell equal areas construction. Convergence to isothermal liquid vapor equilibrium will be shown and discussed. Inclusion of an equation of state for real fluid and better incorporation of force term is presented [4] [5]. Multi-range interactions have been used for SC model [8], but it hasn't been yet applied to real fluid with non-ideal equation of state. In this work, we evaluate this model when it is applied to real liquid-vapor equilibrium. We show that important differences are found for evaluation of gas density. In order to recover thermodynamic consistency, we use a new scheme for calculation of force term, which is a combination of multi range model and numerical weighting used by Gong & Cheng [6] [7]. We show the superiority of our new model by studying convergence to equilibrium values over a large temperature range. We prove that spurious velocities remaining at equilibrium are decreased. [ABSTRACT FROM AUTHOR]

Phase transitions are ubiquitous phenomena, exemplified by the melting of ice and spontaneous magnetization of magnetic material. In general, a phase transition is associated with a symmetry breaking of a system; occurs due to the competition between coupling interaction and external fields such as thermal energy. If the phase transition occurs with no latent heat, the system experiences continuous transition, also known as second order phase transition. The ferromagnetic q-state Potts model with r extra invisible states, introduced by Tamura, Tanaka, and Kawashima [Prog. Theor. Phys. 124, 381 (2010)], is studied by using the Wang-Landau method. The density of states difference (DOSD), ln g(E + △E) - ln g(E), is used to investigate the order of the phase transition and examine the critical value of r changing the second to the first order transition. [ABSTRACT FROM AUTHOR]

We present a detailed infrared study of the semiconductor-to-metal transition (SMT) in a vanadium dioxide (VO2) film deposited on silicon wafer. The VO2 phase transition is studied in the mid-infrared (MIR) region by analyzing the transmittance and the reflectance measurements, and the calculated emissivity. The temperature behaviour of the emissivity during the SMT put into evidence the phenomenon of the anomalous absorption in VO2 which has been explained by applying the Maxwell Garnett effective medium approximation theory, together with a strong hysteresis phenomenon, both useful to design tunable thermal devices to be applied for the thermal control of spacecraft. We have also applied the photothermal radiometry in order to study the changes in the modulated emissivity induced by laser. Experimental results show how the use of these techniques represent a good tool for a quantitative measurement of the optothermal properties of vanadium dioxide based structures. [ABSTRACT FROM AUTHOR]

A numerical simulation of shock experiments on Cerium is reported in the present, by using a multiphase equation of state (MEOS), a multiphase Steinberg-Guinan (MSG) constitutive model and non-equilibrium phase transition process for Cerium. A volume change of about 15% occurs when Cerium is subject to high pressure (~0.7 GPa) and γ→α phase change takes place. The phase transition and constitutive model are coupling and it is hard to distinguish by single experiment. The passive confined pressure SHPB test method can give the pressure-volume under dynamic loading and release including the phase transition character of Cerium. The free surface/window velocity which coupling the information of phase transition and constitutive model can also be given by the plane impact experiment. This is an attempt by two kinds of experiment to obtaining a multiphase equation of state, constitutive model and non-equilibrium phase transition equation. [ABSTRACT FROM AUTHOR]

We derive the thermodynamic conditions necessary for two elasto-plastic solid phases to coexist in equilibrium. In doing so, we examine the well-known case of inviscid fluids and note the underlying physical principles so that we apply them to the case of solids. Beyond temperature, velocity, and traction continuity, these conditions require continuity of a generalization of the specific Gibbs free energy. We express this quantity in the Eulerian frame, as well as the Lagrangian frame. We also show that two approaches in deriving the equilibrium conditions, one on the continuum level and the other on the atomistic scale, yield the same results. [ABSTRACT FROM AUTHOR]

The alloy Ti-6Al-4V is used extensively in industry, and so an accurate equation of state (EoS) is needed for hydrocode simulations involving this material. An accurate model should include phase transitions, where across a phase boundary discontinuities in energy, density and other properties of the material are seen. Due to the limited data available for the alloy a multiphase EoS is first generated for pure titanium, before using a scaling method to obtain an EoS for Ti-6Al-4V. However, the final EoS produces a region of instability on the Hugoniot that has not been observed experimentally, and thus further improvements to the model are needed. Recommendations for future study are made, as well as detailing the difficulties faced using the current approach. Also, as an interim measure, a single phase analytic EoS is generated which shows good agreement with the data available. [ABSTRACT FROM AUTHOR]

Full or partial melting under shock compression or upon release following a shock wave and subsequent fragmentation in the melted state are still essentially open questions in most metals. We present laser shock experiments performed on tin and aluminium, to pressures ranging from about 60 to 250 GPa. Diagnostics include Photonic Doppler Velocimetry (PDV) measurements of the free surface velocity, transverse observations of the expanding cloud of droplets sometimes referred to as 'micro-spall', and soft recovery of such droplets within a low density gel. Multi-phase equations of state are used to infer the evolution of the thermodynamic state along shock propagation distance, accounting for the decay of the loading pressure pulse, and for the presence of mixed regions in the phase diagrams. Experimental observations are interpreted on the basis of hydrodynamic simulations of laser-matter interaction and shock response involving the above multi-phase equations of state. [ABSTRACT FROM AUTHOR]

Results are presented on measurement of sound velocities in shock-compressed samples of zinc and titanium alloy. The measurements were performed by rarefaction overtake method with use of indicator liquids carbogal, tetrachlormethane, and bromoform. Based on results of tests with use of indicator liquids, boundaries of melting of zinc at the shock adiabat were revealed. The obtained experimental data were compared to available data from the other authors. [ABSTRACT FROM AUTHOR]

We present here the first dynamic Rayleigh-Taylor (RT) strength measurement of a material undergoing solid-solid phase transition. Iron is quasi-isentropically driven across the pressure-induced bcc (α-Fe) → hcp (ε-Fe) phase transition and the dynamic strength of the α, ε and reverted α′ phases have been determined via proton radiography of the resulting Rayleigh-Taylor unstable interface between the iron target and high-explosive products. Simultaneous velocimetry measurements of the iron free surface yield the phase transition dynamics and, in conjunction with detailed hydrodynamic simulations, allow for determination of the strength of the distinct phases of iron. Forward analysis of the experiment via hydrodynamic simulations reveals significant strength enhancement of the dynamically-generated ε-Fe and reverted α′-Fe, compareable in magnitude to the strength of austenitic stainless steels. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the unloading behavior of molybdenum at shock pressures approaching the melt regime, particularly in the vicinity of a previously reported solid-solid transition. Symmetric impact experiments were conducted using a two-stage light gas gun and VISAR diagnostic system to examine molybdenum's behavior up to pressures of 305 GPa. The approach required compensating for the wave interaction due to the low impedance LiF window, but provided detailed information regarding the release state and comparison of the measured sound speeds support the existence of the phase transition. This paper describes the strategy, experimental method, and corresponding results which are used to draw conclusions about the dynamic behavior of molybdenum at high pressure. [ABSTRACT FROM AUTHOR]

Hexanitrostilbene (HNS) is an energetic ingredient that is widely used in commercial and military explosives for its thermal stability. However, characterization of its thermodynamic parameters and phase stability is lacking. Crystalline properties, such as bulk modulus and thermal expansion, are necessary to accurately predict the behavior of shocked solids using hydrodynamic codes. In order to obtain these values, equations of state of fine-particle (type IV) HNS were investigated using synchrotron angle-dispersive x-ray diffraction experiments at static high-pressure and temperature. The samples were compressed and heated using diamond anvil cells. Pressure - volume data for HNS at ambient temperature were fit to the Birch-Murnaghan and Vinet formalisms to obtain bulk modulus and its first pressure derivative. Temperature - volume data at ambient pressure were fit to obtain the volume thermal expansion coefficient. [ABSTRACT FROM AUTHOR]

In this work we apply random graph theory approach to describe neural population dynamics. There are important advantages of using random graph theory approach in addition to ordinary and partial differential equations. The mathematical theory of large-scale random graphs provides an efficient tool to describe transitions between high- and low-dimensional spaces. Recent advances in studying neural correlates of higher cognition indicate the significance of sudden changes in spacetime neurodynamics, which can be efficiently described as phase transitions in the neuropil medium. Phase transitions are rigorously defined mathematically on random graph sequences and they can be naturally generalized to a class of percolation processes called neuropercolation. In this work we employ mean-field graphs with given vertex degree distribution and edge strength distribution. We demonstrate the emergence of collective oscillations in the style of brains. [ABSTRACT FROM AUTHOR]

We derive an a useful priori estimate for the thermal ground state of deconfining phase of SU(2) Yang-Mills thermodynamics in four-dimensional, flat spacetime and discuss its implications. Upon a selfconsistent spatial coarse-graining over noninteracting, trivial-holonomy (BPS saturated) (anti)calorons of unit topological charge modulus an inert, adjoint scalar field |Φ| and an effective pure-gauge configuration aμgs emerge. The modulus |Φ| > 0 defines the maximal resolution in the coarse-grained theory and induces dynamical gauge-symmetry breaking. Thanks to perturbative renormalizability and the fact that |Φ| can not absorb or emit energy-momentum the effective action is local and simple. The temperature dependence of the effective coupling is a consequence of thermodynamical consistency and describes the Coulomb screening of a static test charge due to short-lived monopole-antimonopole pairs. The latter occur unresolvably as small-holonomy excitations of (anti)calorons by the absorption of propagating fundamental gauge fields. [ABSTRACT FROM AUTHOR]

The study of properties of hot nuclei and the search for liquid-gas phase transition in nuclei have been the subjects of many investigations in recent decades. We present a short and limited review of the theoretical and experimental status of determining the temperature and density of the disassembling nucleus from ratios of the yields of emitted fragments. [ABSTRACT FROM AUTHOR]

Crystallization represents a kind of phase transition, which can be regarded as a microscopic process related to bond formation and breaking. Both experimental observation and theoretical simulation were carried out to clarify the crystallization behaviors of inorganic materials. Crystallization behaviors of some inorganic materials at nano- and micro-scales, for example, the nucleation sites generation, crystallization driving force, and morphology evolution, were well recorded and observed respectively, which can be controlled effectively by some proposed crystallization strategies. According to the chemical bonding characteristics of constituent atoms, the ideal morphologies and growth morphologies of a series of inorganic materials were simulated by using the chemical bonding theory of single crystal growth, which agree well with experimental observations. The simulated results indicate that microscopic constituent chemical bonds allow us to comprehensively understand the crystallization mechanism on the basis of quantitative calculations of the growth rate in different crystal faces. The chemical bonding theory builds up a bridge between the crystallographic structure, growth morphology and microscopic chemical bonds of crystal materials, which provides us a useful microscopic tool to quantitatively study single crystal growth behaviors. [ABSTRACT FROM AUTHOR]

We review our studies on the dynamics of Si(111) surface morphology. In this work, low-energy electron microscopy, one of the best techniques for in situ observations of surface morphology changes and nanostructure formation, plays a crucial role. The size evolution of two-dimensional islands and vacancy islands during annealing enables us to understand the surface mass transport properties. We find unique step instabilities during homoepitaxial growth and phase transition and clarify their mechanisms. We also investigate formation of Au islands on Si(111) as a prototypical system for controlling the arrangement of nanostructures using steps. [ABSTRACT FROM AUTHOR]

The ZnO is one of the best transparent conducting oxide (TCO) materials for optoelectronic properties. Primarilly three phases of ZnO namely wurtzite, rocksalt and zincblend along with other prominent phases under different pressure and with different phase transformation routes are reported. The route of phase transformation may differ and depends on the external parameters such as pressure. The conventional route for the phase transformation of wurtzite (B4) phase into CsCl type (B2) phase via rocksalt phase (B1) is estimated at the relatively high pressure value of the 256 GPa. In present paper, we propose a new route of transformation of B4 to B2 phase of ZnO via β-BeO type phase at relatively low pressure value of 43 GPa. In present study, the phase transformation analysis and the electronic structure analysis for different phases are carried out by using density functional theory (DFT). It is also observed that B2 phase have high dispersive nature of bottom of conduction band and consequently high mobility of charge carriers. It indicates the possibility of B2 phase may have better TCO properties among other phases of ZnO. [ABSTRACT FROM AUTHOR]

The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi4+dTi4O15 (δ =2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (Tm) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (Pr ~ 12.5 µC/cm²), low coercive fields (Ec ~26 kV/cm) are measured and a high piezoelectric coefficient (d33 ~ 29 pC/N) is achieved in poled BaBi4Ti4O15 ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi4Ti4O15 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth. [ABSTRACT FROM AUTHOR]

A Monte Carlo study of non-equilibrium phase transition from dynamic ordered to dynamic disordered state is performed using kinetic Ising model in presence of external time dependent sinusoidal magnetic field. Hysteresis loop appears in dynamic phase transition as the instantaneous magnetization usually does not follow the external field. As the temperature around dynamic transition temperature Tc is varied, the shape and orientation of the hysteresis loop change. Studying the change in geometry of the hysteresis loop, the dynamical phase transition is characterized here. [ABSTRACT FROM AUTHOR]

In the present paper, we have investigated the high-pressure structural phase transition and elastic properties of cerium mono-nitride. We studied theoretically the structural properties of this compound (CeN) by using the improved interaction potential model (IIPM) approach.. This compound exhibits first order crystallographic phase transition from NaCl (B1) to tetragonal (BCT) phase at 37 GPa. The phase transition pressures and associated volume collapse obtained from present potential model (IIPM) show a good agreement with available theoretical data. [ABSTRACT FROM AUTHOR]

Ab-initio total energy calculations have been performed in lutetium nitride (LuN) as a function of hydrostatic compression to understand the high pressure behavior of this compound. Our calculations predict a phase transition from ambient rocksalt type structure (B1 phase) to a tetragonal structure (B10 phase) at ~ 240 GPa. The phase transition has been identified as first order in nature with volume discontinuity of ~ 6%. The predicted high pressure phase has been found to be stable up to at least 400 GPa, the maximum pressure up to which calculations have been performed. Further, to substantiate the results of static lattice calculations analysis of lattice dynamic stability of B1 and B10 phase has been carried out at different pressures. Apart from this, we have analyzed the lattice dynamic stability CsCl type (B2) phase around the 240 GPa, the pressure reported for B1 to B2 transition in previous all-electron calculations by Gupta et al. 2013. We find that the B2 structure is lattice dynamically unstable at this pressure and remains unstable up to ~ 400 GPa, ruling out the possibility of B1 to B2 phase transition at least up to ~ 400 GPa. Further, the theoretically determined equation of state has been utilized to derive various physical quantities such as zero pressure equilibrium volume, bulk modulus, and pressure derivative of bulk modulus of B1 phase at ambient conditions. [ABSTRACT FROM AUTHOR]

Vibrational properties of ternary chalcopyrite semiconductor CuGaTe2 have been studied using Raman spectroscopy at high pressures upto 24 GPa. Pressure dependent softening is observed for two of the observed modes, which has been correlated with instability in the system leading to structural transition around 9 GPa to a disordered simple cubic phase. Beyond 11.5 GPa, no Raman spectra could be observed. This is possibly due to the transition could be also accompanied by reduction in band gap. On release of pressure, structurally disordered chalcopyrite phase is recovered. [ABSTRACT FROM AUTHOR]

Results from shock-wave loading of germanium are presented. Germanium is known to transition from ambient cubic diamond (cd) phase to the high-pressure body-centered tetragonal (bct) or β-tin phase at pressures between 10 and 12 GPa. Large-scale molecular dynamics (MD) simulations were used to study the phase transition in single-crystal germanium under uniaxial compression along the <001> and <111> orientations. We observed that the transition from the cd phase to the bct phase nucleates through shear banding and advances to relieve uniaxial strain. The macroscopic properties are compared with experimental results for the Modified Embedded Atom Method (MEAM) and Tersoff potentials. [ABSTRACT FROM AUTHOR]

The graphite-diamond transformation was studied under conditions of shock compression at initial temperatures of 293 K and 750 K. The VISAR particle velocity histories were recorded at the interface between a graphite sample and a LiF window. Results of measurements at normal and elevated temperatures were analyzed using wide-range equations of state of graphite, LiF and aluminum. It has been found the transition pressure decreases with heating from 18.9 to 16.9 GPa and from 20.3 to 18.3 GPa for graphites with 5% and 27% of rhombohedral phase, respectively. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene (PTFE) is a complex semicrystalline polymer with four pressure and temperature dependent crystalline phases. As has been recently studied, the crystalline region grows with load. Shock-wave profiles reported from embedded gauges demonstrate features that may be related to impedance mismatches between the regions subjected to some transitions resulting in density and modulus variations. We consider the amorphous-to-crystalline and the high-pressure Phase II–III transitions in the current simulation analysis. The present work utilizes a multi-phase rate sensitive model to describe shock response of the PTFE material. One-dimensional experimental shock wave histories are compared with calculated profiles using kinetics describing the transitions. The objective of this study is to understand the role of the various transitions in the shock response of PTFE. [ABSTRACT FROM AUTHOR]

For several decades, experiments have shown the behavior under shock of materials featuring phase transitions. They exhibit shock splitting and rarefaction shocks. If the main phenomena are now understood, most studies are limited to the qualitative behavior, and a quantitative analysis of experimental results remains to be done in most cases involving complex materials, waves or geometries. In the present study, we have undertaken calculations on ice to reproduce quantitatively an impact experiment on ice with double phase transition. We have built a six phases equation of state (EOS) for ice which reproduces experimental equilibrium phase diagram and Hugoniot curves. Our first hydro calculations provide the pressure levels, but exhibit an elastic precursor and kinetics of phase transition effects. [ABSTRACT FROM AUTHOR]