Discovery of a low-density filled-ice phase in nitrogen hydrate at high pressure

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A Fortran program that can be applied to simulate the four-dimensional dynamical structure factors (Dysurf) for inelastic neutron and inelastic X-ray scattering experiments is presented. With the underlying theoretical formalism, the detailed implementation of the program is described. Based on the second-order force constants from the first-principles method, the Dysurf code can well reproduce the measured spectroscopies of those scattering experiments. Four main applications of this code with the correspo

• Duplex Fe–Mn–Si SMAs were designed by adjusting Si and Cr contents, yielding controlled austenite–ferrite phase fractions. • Duplex microstructures significantly increased yield strength while maintaining comparable recovery stresses to the single-phase alloy. • Higher Cr contents improved corrosion resistance in chloride-containing environments. • Results establish composition–microstructure guidelines for strengthening Fe–Mn–Si SMAs without degrading functional performance. In this study, novel FeMnSi-b

The insulating chiral magnet Cu2OSeO3 exhibits a rich array of low-temperature magnetic phenomena, making it a prime candidate for the study of its spin dynamics. Using spin wave small-angle neutron scattering (SWSANS), we systematically investigated the temperature-dependent behavior of the helimagnon excitations in the field-polarized phase of Cu2OSeO3. Our measurements, spanning 5-55 K, reveal the temperature evolution of spin-wave stiffness and damping constant with unprecedented resolution, facilitated

Lithium thiophosphate (LPS) is a promising solid electrolyte for next-generation lithium-ion batteries due to its superior energy storage, high ionic conductivity, and low-flammability properties. Despite its potential, the high reactivity of LPS with common contaminants such as atmospheric water, preparation solvents, and electrode materials poses significant challenges for commercialization. The lack of understanding regarding the structure, morphology, and chemical behavior of the surface of LPS slows do

Reliable predictions of sea level rise require a quantitative understanding of the mass balance of the Antarctic ice sheet. Water vapor exchange between snow and the atmospheric boundary layer may be an important term in the mass balance equation but current estimates for this process are highly uncertain. The exchange of water vapor becomes particularly strong during drifting and blowing snow events, which are frequent in Antarctica. In these conditions, measured turbulent ﬂuxes based on the Eddy–Covarianc

Although fluids are pervasive among tectonic faults, thermo-hydro-mechanical couplings during earthquake slip remain unclear. In particular, fluid induced seismicity is today a subject of major interest for the geo-energy community. We report full dynamic records of stick-slip events, performed on saw cut Westerly Granite samples loaded under triaxial conditions (stresses σ1> σ2= σ3) at pressures representative of the upper continental crust (σ3~ 45-95 MPa) Three fluid pressure conditions were tested, dry,

We report on the Gouy phase anomaly of light in the focus of cylindrical and spherical microlenses. The prime subject of our study concerns a discussion of how the very small size of microlenses affects the phase properties of light in their foci. We put emphasis on determining the amount of the Gouy phase shift for line and point foci within the limited axial space. Contrary to macroscopic lenses, the optical properties of microlenses are strongly governed by the effect of diffraction when their size tends

Detailed thermodynamic and kinetic study of the aqueous Kolbe-Schmitt synthesis of beta-resorcylic acid has been carried out in a laboratory-scale batch reactor operated under ambient pressure. The dependence of the conversion on partial pressure of carbon dioxide (4 x 10(-4) - 1 bar), initial concentration of resorcinol (0.4-0.8 M), initial concentration of potassium bicarbonate (0.4-6 M) and temperature (348-428 K) was studied. The reaction was found to be reversible and exothermic (Delta H = -30.4 kJ/mol

This paper presents numerical simulations of annular laminar film condensation heat transfer in micro-channels of different internal shapes. The model, which is based on a finite volume formulation of the Navier-Stokes and energy equations for the liquid phase only, importantly accounts for the effects of axial and peripheral wall conduction and non-uniform heat flux not included in other models so far in the literature. The contributions of the surface tension, axial shear stresses and gravitational forces

We report on the dependence on temperature of the homogeneous and inhomogeneous broadening of the fundamental transition of single polar GaN/AlN quantum dots (QDs). Stranski-Krastanov QDs have been grown by molecular beam epitaxy using NH3 as a nitrogen source, with a very low surface density. Low temperature (LT) microphotoluminescence measurements have been performed on 200 nm wide mesas in order to isolate the luminescence of single QDs. The linewidth is found to vary from 590 mu eV at 4 K up to 1350 mu

We introduce a minimal model describing the physics of classical two-dimensional (2D) frustrated Heisenberg systems, where spins order in a nonplanar way at T=0. This model, consisting of coupled trihedra (or Ising-RP3 model), encompasses Ising (chiral) degrees of freedom, spin-wave excitations, and Z2 vortices. Extensive Monte Carlo simulations show that the T=0 chiral order disappears at finite temperature in a continuous phase transition in the 2D Ising universality class, despite misleading intermediate

Systems with a ferroelectric to paraelectric transition in the vicinity of room temperature are useful for devices. Adjusting the ferroelectric transition temperature (T-c) is traditionally accomplished by chemical substitution - as in BaxSr1-xTiO3, the material widely investigated for microwave devices in which the dielectric constant (epsilon(r)) at GHz frequencies is tuned by applying a quasi-static electric field(1,2). Heterogeneity associated with chemical substitution in such films, however, can broad

Urotropin (U) and azelaic acid (AA) form 1:1 co-crystals (UA) that give rise to a rather complex diffraction pattern, the main features of which are diffuse rods and bands in addition to the Bragg reflections. UA is characterized by solvent inclusions, parasite phases, and high vacancy and dislocation densities. These defects compounded with the pronounced tendency of U to escape from the crystal edifice lead to at least seven exotic phase transitions (many of which barely manifest themselves in a different

In this work, new spectroscopic techniques have been developed to measure electric dipole moments of highly excited rovibrational states of small polyatomic molecules in the gas phase. These techniques make use of lasers arid of microwave synthesizers. They enable one to measure the change on a molecular system caused by applying an external electric field, which is called Stark effect and from this, extract the dipole moment. The first technique, called microwave Stark spectroscopy, makes use of microwave-

A transmission electron microscopy (TEM) study using weak-beam imaging has been addressed in order to assess the microstructure of NiAl (100) single-crystals subsequently to irradiation at room temperature with 700 keV nickel ions up to 10(15) cm(-2) or 1.5 dpa, namely, defect cluster formation and respective depth distribution. This work shows that the incoming ions undergo channeling along the [100] crystallographic direction and that the actual projected range is approximately 500 nm instead of the 250 n

A low temperature method of bonding two polymer sheets (2, 3) without adhesive, at least one of said polymer sheets comprising a microstructure (1) or a network of microstructures, comprises the steps of treating at least a portion of one surface of one of said polymer sheets by using a cold plasma or a laser beam so as to physically activate said portion at low temperature, placing the two polymer sheets in contact, with the activated portion of said one sheet in contact with the other sheet, and subjectin

The structural buildup during reticulation of thermoset systems containing reactive modifiers can strongly influence the final properties of such blends. This was studied by considering the rheological behavior during cure of an epoxy/amine thermoset system blended with reactive dendritic hyperbranched polymers (HBPs). Depending on the chemical structure of the HBP used in the blend, a phase separation could be observed. The onset and offset of the phase separation process could be detected by observing the

The influence of cure temperature, composition and chemical structure on the morphology resulting from chemically induced phase separation has been investigated for different epoxy functionalized dendritic hyperbranched polymers blended with diglycydil bisphenol A and an aliphatic diamine. The cure temperature window chosen highlighted the influence of both the kinetics of phase separation and the thermodynamics of mixing on the final morphology. In relatively immiscible blends and at low cure temperatures,

In this study, chaotic wandering phenomenon observed in simple coupled chaotic circuits is modeled by Markov chains. As coupling parameter increases, the solution of the coupled chaotic circuits starts to wander chaotically over 6 different phase states which are stable for smaller value of the parameter. The wandering is modeled by a first order and sedond order Markov chains with the 6 states plus 3 intermediate states. Stationary probability function, expected sojourn time and probability density of sojo

Electrode stability, interdiffusion, phase purity and deviation from stoichiometry at the PZT-electrode interface are key issues in PZT thin film integration. This article highlights the use of transmission electron imaging combined with energy dispersive spectroscopy (EDS) for the investigation of these phenomena. The accuracy of the EDS analysis is discussed. It will be shown that using a standard PZT sample and controlled conditions, reliable analysis can be performed. Diffusion mechanisms have been stud

Discovery of a low-density filled-ice phase in nitrogen hydrate at high pressure

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Dysurf: A program for simulating four-dimensional dynamical structure factor

Development and characterization of FeMnSi-based shape-memory alloys with austenitic–ferritic duplex microstructure

Helical spin dynamics in Cu2OSeO3 as measured with small-angle neutron scattering

Reconstructions and Dynamics of β -Lithium Thiophosphate Surfaces

Constraining Latent and Sensible Heat Fluxes during Drifting and Blowing Snow Events in Antarctica using in–situ Measurements and Large–Eddy Simulations

Fluid thermodynamics control fault heating and weakening under upper crustal stress conditions

Experimental and theoretical study of the Gouy phase anomaly of light in the focus of microlenses

Kinetic and thermodynamic study of the aqueous Kolbe–Schmitt synthesis of beta-resorcylic acid

Numerical Modeling of the Conjugate Heat Transfer Problem for Annular Laminar Film Condensation in Microchannels

Homogeneous and inhomogeneous linewidth broadening of single polar GaN/AlN quantum dots

Thermal destruction of chiral order in a two-dimensional model of coupled trihedra

Room-temperature ferroelectricity in strained SrTiO3

Urotropin azelate: a rather unwilling co-crystal

Electric dipole moments of highly excited molecular vibrational states

Channeling effects in heavy-ion irradiated NiAl(100) single-crystals: a TEM assessment in cross-section geometry using weak-beam imaging

Polymer bonding by means of plasma activation

Phase Separation and Gelation of Epoxy Resin/Hyperbranched Polymer Blends

Morphology build-up in dendritic hyperbranched polymer modified epoxy resins: Modelling and characterisation

Markov chain modeling of chaotic wandering in simple coupled chaotic circuits

Stoichiometry and interdiffusion in PZT thin films studied by transmission electron microscopy