Phase coexistence properties of liquid mercury:a simulation study

The thermophysical properties of expanded liquid mercury have been investigated along the liquid-vapor coexistence curve by using Monte Carlo and Molecular Dynamic simulations. For the purpose, an empirical state dependent interatomic potential for the region of dense metallic liquid is used, while the state dependence is not necessary near the cliffcal point. In order to test the validity of this potential, we determine the surface layering and the sound velocity, two properties very sensitive to the choice of the potential. Our results are in quite good agreement with other theoretical results and to the experimental data available in the literature.

Electromechanical phase transition of a dielectric elastomer tube under internal pressure of constant mass

The electromechanical phase transition for a dielectric elastomer （DE） tube has been demonstrated in recent experiments, where it is found that the unbulged phase gradually changed into bulged phase. Previous theoretical works only studied the transition process under pressure control condition, which is not consistent with the real experimental condition. This paper focuses on more complex features of the electromechanical phase transition under internal pressure of constant mass. We derive the equilibrium equations and the condition for coexistent states for a DE tube under an internal pressure, a voltage through the thickness and an axial force. We find that under mass control condition the voltage needed to maintain the phase transition increases as the process proceeds. We analyze the entire process of electromechanical phase transition and find that the evolution of configurations is also different from that for pressure control condition.

Fabrication and Characterization of Au Nanoparticle-aggregated Nanowires by Using Nanomeniscus-induced Colloidal Stacking Method

We fabricate and characterize Au nanoparticle-aggregated nanowires by using the nano meniscus-induced colloidal stacking method. The Au nanoparticle solution ejects with guidance of nanopipette/quartz tuning fork-based atomic force microscope in ambient conditions, and the stacking particles form Au nanoparticle-aggregated nanowire while the nozzle retracts from the surface. Their mechanical properties with relatively low elastic modulus are in situ investigated by using the same apparatus.

Non-equilibrium Phases Formed in Cu–In–Se–Te System Synthesized by Melt-Quench Method

Non-equilibrium phases formed in melt-quenched CuIn（SexTe1-x）2 system, where x = 0.1, 0.2, 0.4, 0.5, 0.6, 0.8 and 0.9, have been studied using Rietveld refinement of the crystal structure and Raman spectroscopy. Results of structure refinement have showed that all the samples, except the CuIn（Se0.1Te0.9）2, are heterogeneous. All the observed non-equilibrium phases are quaternary system and are found to have chalcopyrite structure （I42d）, in accordance with the CuInTe2-CuInSe2 phase diagram. The lattice constants deduced from the refinement have showed linear variation with Se content. A detailed analysis of the characteristic Al modes present in the Raman spectrum of individual sample has corroborated the results obtained from the structure analysis. The position of Al mode of individual phase is found to vary linearly with Se content, which suggests that CuIn（SexTe1-x）2 system exhibits single-mode behaviour.

Nanostructures formation in ferroelectrics in the process of phase transformation

Received 26 June 2014;Revised 13 October 2014;Accepted 20 October 2014;Published 12 November 2014 Inhomogeneous states caused by the coexistence of the ferroelectric(FE)and antiferroelectric(AFE)phases in lead–zirconate–titanate based solid solutions have been investigated.It has been found that the domains of the FE and AFE phases with sizes of the order of 20 nm to 30 nm coexist in the bulk of the samples due to a small difference in the free energies of these phases.The coherent character of the interphase boundaries(IPBs)leads to the concentration of the elastic stresses along these boundaries.These elastic stresses cause the local decomposition of the solid solution and formation of segregates near the IPBS due to the condition that equivalent positions of the crystal lattice are occupied by the ions with different sizes.The sizes of the segregates formed in this way are of the order 8 nm to 15 nm.Some physical effects caused by the presence of these segregate nanostructures are analyzed and discussed.

Effects of single particle on shape phase transitions and phase coexistence in odd-even nuclei

A classical analysis of shape phase transitions and phase coexistence in odd-even nuclei has been performed in the framework of the interacting boson-fermion model. The results indicate that the effects of a single particle may influence different types of transitions in different ways. Especially, it is revealed that phase coexistence can clearly emerge in the critical region and thus be taken as a indicator of the shape phase transitions in odd-even nuclei.

Enhanced maximum energy product of(SmY)FeN caused by abundant yttrium doping

Replacement of samarium(Sm) with abundant yttrium(Y) can help solve the potential shortage of Sm in the preparation of promising Sm2 Fe17 Nx magnets.In this article,phase composition,microstructure and magnetic properties of(Sm1-yYy)2 Fe17Nx(y=0,0.2,0.4,0.6,0.8,1.0) were investigated.Maximum energy product(BH)max is improved when less than 40 at% Y is doped in(Sm1-yYy)2 Fe17Nx powder.In particular,when 20 at% Y replaces Sm,(BH)max of(Sm1-yYy)2 Fe17Nx powder increases by 15.1% from 131.7 to151.6 kJ/m3.The effect of annealing temperature on the structural properties of high Y doping(Sm0.6Y0.4)2 Fe17 and the magnetic properties of the corresponding nitrides were subsequently investigated.In the RE2 Fe17 phase grain combination process,the interlaced structure of the rhombohedral Th2 Zn17-type structural phase and the hexagonal Th2 Ni17-type structural phase is formed.Due to shortrange exchange coupling,the nitride with the highest content of two interlaced RE2 Fe17 phases has the highest magnetic properties:Br=1.23 T,HcJ=443.9 kA/m and(BH)max=197.6 kJ/m3.

Magnetic properties of rare earth HoCrO_3 chromites

The temperature dependence of the magnetic properties was systemically studied by dc/ac magnetization and specific heat measurement for heavy rare earth HoCrO3 chromites.The results revealed the existence of complex phase coexistence and competitive magnetic behavior in HoCrO3 chromites.It was found that,in the region of higher temperature above 141.0 K,HoCrO3 behaved as a typical Curie-Weiss paramagnetic（PM）.And in the region of low temperature,a novel magnetization behavior was observed with negative magnetization（diamagnetism-like） characteristics under an external field of 100 Oe and M-T curves exhibited two symmetrical branches for field cooling（FC） and zero field cooling（ZFC） modes.This behavior indicated the coexistence of canted antiferromagnetic（CAFM） and weak ferromagnetic（FM） phase.These also exhibited the existence of competition mechanism below characteristic temperature TN1=141.0 K and the magnetic order of Ho ion below 7.5 K.The current complex magnetization might be attributed to the interaction between paramagnetic Ho3＋ moments and canted Cr3＋ moments.

On Stochastic Error and Computational Efficiency of the Markov Chain Monte Carlo Method

InMarkov ChainMonte Carlo(MCMC)simulations,thermal equilibria quantities are estimated by ensemble average over a sample set containing a large number of correlated samples.These samples are selected in accordance with the probability distribution function,known from the partition function of equilibrium state.As the stochastic error of the simulation results is significant,it is desirable to understand the variance of the estimation by ensemble average,which depends on the sample size(i.e.,the total number of samples in the set)and the sampling interval(i.e.,cycle number between two consecutive samples).Although large sample sizes reduce the variance,they increase the computational cost of the simulation.For a given CPU time,the sample size can be reduced greatly by increasing the sampling interval,while having the corresponding increase in variance be negligible if the original sampling interval is very small.In this work,we report a few general rules that relate the variance with the sample size and the sampling interval.These results are observed and confirmed numerically.These variance rules are derived for theMCMCmethod but are also valid for the correlated samples obtained using other Monte Carlo methods.The main contribution of this work includes the theoretical proof of these numerical observations and the set of assumptions that lead to them.

Effects caused by antiferroelectric nanodomains in PZT-based coarse-grained ceramics with compositions from the morphotropic boundary region

Presented results demonstrate importance of taking into account such a phenomenon as the solid solution decomposition at the boundaries separating coexisting phases in lead zirconate-titanate-based solid solutions with compositions belonging to the morphotropic boundary region of the"temperature–composition"phase diagram.It is shown that in the local decomposition of solid solutions in the vicinity of the boundaries separating the tetragonal and rhombohedral phases in lead zirconate-titanate-based solid solutions lead to the changes of the solid solution's chemical composition and to the formation of segregates.It is also shown that the proper thermoelectric treatment of samples containing these segregates can give substantially higher values of piezoelectric parameters in the lead zirconate-titanate-based compounds.

A study on organized assemblies in the sodium alkylcarboxylate/fatty alcohol/water systems

The phase behavior and evolution of self-organized assembling structures in the sodium alkylcarboxylate/fatty alcohol systems were investigated by TEM. With increasing concentration of fatty alcohol, the micells transform into lamellar La phase, sponge L3 phase, multilamellar vesicle, and transform back to lamellar La phase. At higher alcohol concentration, a stable two aqueous phase coexisting region has been observed in this kind of systems after aged two months. Unilamellar vesicles were found both in two separated phases but the vesicle density of the upper phase is much higher than that of me bottom phase.