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Semipermeable membranes play critical roles in many natural and engineering systems. The osmotic pressure is found experimentally much less effective than the hydraulic pressure to drive water through the membrane, which is commonly attributed to the internal concentration polarization (ICP) in the porous layer of the membrane. In this study, it has been shown that a necessary condition for the osmotic pressure to be effective is water continuity across the entire membrane thickness under negative pressure, i.e., the water inside the membrane remains in a metastable state. However, the metastable state of water cannot be maintained indefinitely, and cavitation will undoubtedly occur in the osmotically driven processes. Collapse of the water metastable state was suggested for the first time to be a more important and fundamental reason for the low water fluxes in the osmotically driven membrane processes.

To utilize magnetic skyrmions, nanoscale vortex-like magnetic structures, experimental elucidation of their dynamics against current application in various circumstances such as in confined structure and mixture of different magnetic phases is indispensable. Here, we investigate the current-induced dynamics of the coexistence state of magnetic skyrmions and helical magnetic structure in a thin plate of B20-type helimagnet FeGe in terms of in situ real-space observation using Lorentz transmission electron microscopy. Current pulses with various heights and widths were applied, and the change of the magnetic domain distribution was analyzed using a machine-learning technique. The observed average driving direction of the two-magnetic-state domain boundary is opposite to the applied electric current, indicating ferromagnetic s-d exchange coupling in the spin-transfer torque mechanism. The evaluated driving distance tends to increase with increasing the pulse duration time, current density (>1 × 109 A/m²), and sample temperature, providing valuable information about hitherto unknown current-induced dynamics of the skyrmion-lattice ensemble. [ABSTRACT FROM AUTHOR]

The radiative lifetimes of Xe 3+ ions in the metastable 5s 2 5p 3 2 P 3/2 and 2 P 1/2 states were measured by using an electrostatic ion beam trap. The lifetimes were obtained by measuring the number of photons emitted during the 2 P 3/2  →  2 D 3/2 (447 nm) and 2 P 1/2  →  4 S 3/2 (357 nm) forbidden transitions of Xe 3+ , as a function of the storage time. The storage lifetime of the Xe 3+ was simultaneously measured by detecting the Xe ions with changed charge escaping from the trap, which yielded information pertaining to the correction of the collision-induced loss of Xe 3+ in the trap. The obtained lifetimes of 7.0 ± 0.2 ms for the 2 P 3/2 state and 16.6 ± 0.8 ms for the 2 P 1/2 state were compared with previously reported theoretical and experimental values. [ABSTRACT FROM AUTHOR]

The previously proposed model for the kinetics of first-order phase transitions (Barsuk et al., 2013) is generalized for r order and m control parameters. Bifurcation and stability analyses of the equilibrium states in thermodynamic systems described by the Landau-type kinetic potential with two order parameters is performed both in the absence of an external field, and in the presence of constant and periodic external fields. Kinetics of thermodynamic systems described by such potential in a small neighborhood of the equilibrium states is also studied. Mean transition time for lysozyme protein in dependence of control parameters is obtained based on the developed model. A detailed bifurcation analysis of the cubic equation solutions is given in Appendix. [ABSTRACT FROM AUTHOR]

Frictional effects on the wave packet dynamics of quantum systems are investigated in the framework of the Schrödinger–Langevin equation. The Schrödinger–Langevin equation is directly solved using the split-operator method. Frictional effects impede the propagation and suppress the spreading of the wave packet. Computational results are presented for an Eckart barrier scattering problem, the decay of a metastable state, and the long-time behavior of a decaying quantum system. Significant features of dissipative Bohmian trajectory dynamics are analyzed for these quantum processes. [ABSTRACT FROM AUTHOR]

The radiative lifetime of the 3s 2 3p 4 1 S 0 metastable state of Ar 2+ was measured using an electrostatic ion beam trap. The lifetime was obtained by measuring the number of photons emitted during the 1 S 0 → 3 P 1 magnetic dipole transition of Ar 2+ as a function of the storage time. The wavelength of the photons was 311 nm. To correct for the collision-induced loss of Ar 2+ ions in the trap, the storage lifetime of the Ar 2+ beam was measured simultaneously by detecting Ar neutrals escaping from the trap. The obtained radiative lifetime was 157 ± 19 ms, which was comparable to previously reported theoretical and experimental values. [ABSTRACT FROM AUTHOR]

The intermetallic FeRh system has displayed tremendous fascination to investigators due to its remarkable physical properties and potential applications. Here we synthesized near-equiatomic FeRh films on MgO (001) substrate by magnetron co-sputtering of Fe and Rh, and our results revealed a magnetic glass (MG) state existing after field cooling to low temperature. The MG state is nonequilibrium with a configuration of metastable supercooled ferromagnetic (FM) and equilibrium antiferromagnetic (AFM) phases, and arises from a kinetic arrest of the first-order FM–AFM phase transition. Our finding is beneficial to a better understanding of the underlying mechanism of the FeRh phase transition. IMPACT STATEMENT The presence of magnetic glass state over ferromagnetic–antiferromagnetic transition in co-sputtered FeRh film is certified, and may benefit the understanding of the origin of FeRh phase transition and the communities of multiferroic. [ABSTRACT FROM PUBLISHER]

In order to research the adaptivity of the capillary tube in the transcritical CO 2 refrigeration system, a separated flow model of a CO 2 capillary in which the metastable phenomenon was taken into consideration was built in the simulation of transcritical CO 2 refrigeration system, and related experiments were carried out by a plant under different gas-cooler outlet temperatures. The performances of the capillary based system were further compared with that of the EEV (electronic expansion valve) based system. The results showed that the relative COP ranged from 82% to 98% when there was a 10 °C deviation between the real gas-cooler outlet temperature and the design value. Thus the capillary based transcritical CO 2 system is promising and could achieve performance close to that of EEV based system in a wide range of gas-cooler outlet temperature. [ABSTRACT FROM AUTHOR]

Measurements of the transmission of neutrons through two samples of 235U and Cd, which are simultaneously on neutron beam, with different sequence of their location for different exposure times of the samples on the beam, are performed. Previously observed difference in these transmissions is confirmed - asymmetry of transmission. The purpose of the measurements is to determine the lifetime of the expected metastable states, to explain the observed asymmetry of transmission. Based on the results of asymmetry of transmission measurements, it was found that it is less than 5 s. [ABSTRACT FROM AUTHOR]

Layers of amorphous ice were prepared by deposition of supersonic molecular beams of rarefied vapor on a substrate cooled by liquid nitrogen. Molecular beam entered a vacuum chamber through Laval nozzle, which accelerated it to a supersonic speed. An adiabatic expansion of molecular beam leads to a decrease in the temperature at the nozzle outlet and formation of crystalline nanoclusters of water. Under heating of nonequilibrium condensates one could observe a glass transition (softening) and subsequent spontaneous crystallization. The presence of water clusters introduced into nonequilibrium condensates artificially ensured conditions for the initiation of “hot” centers and a transition to an explosive regime of crystallization in an amorphous medium. A theoretical analysis has been made of the role of the thermal conditions in which the crystallization of an amorphous substance proceeds, with allowance for the nonstationary nucleation. [ABSTRACT FROM AUTHOR]

An amphiphilic hyperbranched poly(aryl ether ketone)-graft-poly(ethylene glycol) (HPAEK-graft-PEG) rod–coil copolymer was synthesized by grafting linear PEG onto hydroxyl-terminated HPAEK (OH-HPAEK). The molecular structure, the number-average molecular weight and the thermal properties of HPAEK-graft-PEG were characterized by proton nuclear magnetic resonance and Fourier transform infrared spectroscopies, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis, respectively. The self-assembly behaviors of HPAEK-graft-PEG in the mixed solvents were investigated by transmission electron microscopy and scanning electron microscopy. The results demonstrated that the selective solvent in the used mixed solvents exerted remarkable influence on the morphology of the resulting micelles. When the mixed solvents were water/tetrahydrofuran (THF), trichloromethane/THF, and toluene/THF, that is, with the decrease of the selective solvents in polarity, HPAEK-graft-PEG could self-assemble into the regular microspheres with obvious core–shell structure, the similar quadrilateral-shaped micelles with the dimension of about 20 nm and the large complicated clew-shaped micelles, as well as the irregular large compound micelles, respectively. It is worth mentioning that the similar quadrilateral-shaped micelles were different from the toroidal micelles reported already, which had relatively obvious “angle”. The phenomenon may be ascribed that the rigid characteristic of rod HAPEK segment was conducive to the maintenance of the metastable state. [ABSTRACT FROM AUTHOR]

We show how statistical thermodynamics can be formulated in situations of metaequilibrium or metastability (as in the cases of supercooled liquids or of glasses respectively). By analogy with phenomenological thermodynamics, the primary quantities considered are the heat Q absorbed and the work W performed by the system of interest. These are defined through the energy exchanges which occur when the system is put in contact with a thermostat and with a barostat, the whole system being dealt with as a global Hamiltonian dynamical system. The coefficients of the fundamental form $$\delta Q-\delta W$$ turn out to have such expressions that the closure of the form is manifest: this gives the first principle. A further step is performed by making use of time reversibility. This provides new expressions for the coefficients, such that the second principle in the form of Clausius is also manifest. Such coefficients are expressed in terms of time-autocorrelations of suitable dynamical variables, in a way analogous to that of fluctuation dissipation theory for equilibrium states. All these results are independent of the ergodicity properties of the global dynamical system. [ABSTRACT FROM AUTHOR]

Magnetic skyrmions in Co8Zn8Mn4 thin plates are observed to deform in a metastable state prepared in a magnetic-field-cooling process by way of the thermal-equilibrium skyrmion phase. In cooling, the disk-shape skyrmions change to bar- or L-shaped elongated form, whereas the skyrmion density is nearly conserved. The deformation of the skyrmions in the supercooled metastable phase is observed irrespective of the crystallographic orientation of the thin plate, whereas the elongation direction nearly aligns along the magnetic easy axis. It is proposed that the deformation should be induced by a large increase in magnetic modulation wavenumber when decreasing the temperature, whereas the topological protection of the skyrmions keeps the averaged skyrmion density constant. [ABSTRACT FROM AUTHOR]

We demonstrate here a simple liquid electrolyte soluble Cu-compound, viz., cupric chloride (CuCl 2 ) as an alternative electrocatalyst for nonaqueous Li-CO 2 batteries. The key point behind the selection of CuCl 2 is that the theoretical potential of Li-CO 2 batteries (≈2.8 V; Li + |Li) lies within the Cu 1+ |Cu 0 redox couple (2.3-3.3 V; Li + |Li). The presence of CuCl 2 in the liquid electrolyte near to the carbon nanotubes (≡ coelectrocatalyst)-loaded porous-CO 2 cathode led to efficient electrocatalysis of CO 2 and superior Li-CO 2 battery performance. The cell overpotential in the presence of CuCl 2 is 0.65 V, which is less than half compared to the one without it (≈1.7 V). Extensive investigations precisely elucidate the electrocatalytic mediation of CuCl 2 with the redox characteristics of CO 2 . Additionally, only in the presence of CuCl 2 , the existence of Li-oxalate (Li 2 C 2 O 4 ) is detected, which is a seldomly reported intermediate preceding the formation of Li 2 CO 3 .