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Design of stable high-performance heterogeneous catalysts has become crucial for efficient catalytic conversion of renewable biomass into high value-added chemicals. In this study, amphiphilic polymer support was synthesized by grafting hydrophobic groups onto hydrophilic cellulose nanocrystals and utilized as a support for PdNi alloy nanoparticles. The as-synthesized catalysts exhibited encouragingly high performance in the hydrodeoxygenation of vanillin under mild conditions.

The surface tension and viscosity of equilibrium and supercooled liquids of Cu50Zr50 were measured in the containerless electromagnetic levitator ISS-EML in the European space laboratory Columbus on board the International Space Station (ISS) under microgravity using high-speed camera recordings. From 1250 K to 1475 K, the surface tension follows the relation σ(T) = (1.58 ± 0.01) N/m – (3.1 ± 0.6) · 10−4 N/m · K · (T – 1209 K). A frequency shift correction was applied to remove the influence of sample rotation on the measured surface tension. Within the investigated temperature range, the viscosity can be expressed by an Arrhenius temperature dependence η(T) = η0 · exp(EA/kBT), with η0 = (0.08 ± 0.02) mPa·s and EA = (0.58 ± 0.03) eV.

Mixed and ground activated snail shell and kaolin catalysts impregnated with KBr were investigated. The snail shell and kaolin were calcined, mixed, and ground prior to immersion with KBr solution and subsequent activation at 500 °C for 3 h. The precursor and catalysts were characterized by thermal gravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller surface area. The catalytic performance of the prepared catalysts was evaluated by transesterification of soybean oil with methanol. The effects of various parameters on biodiesel yield were investigated. A biodiesel yield of 98.5% was achieved using the catalyst prepared by 40% KBr-immersed, mixed, and ground snail shell and kaolin, which were activated at 500 °C. The transesterification conditions were as follows: reaction temperature, 65 °C; reaction time, 2 h; methanol-to-soybean oil molar ratio, 6:1; and catalyst amount (relative to the weight of soybean oil), 2.0 wt%. The solid catalyst could be reused for four times, and biodiesel yield remained over 73.6% for the fourth time.

The ten articles [1–10] included in this Special Issue on “Liquid Metals” do not intend to comprehensively cover this extensive field, but, rather, to highlight recent discoveries that have greatly broadened the scope of technological applications of these materials. Improvements in understanding the physics of liquid metals are, to a large extent, due to the powerful theoretical tools in the hands of scientists, either semi-empirical [1,5,6] or ab initio (molecular dynamics, see [7]). Surface tension and wetting at metal/ceramic interfaces is an everlasting field of fundamental research with important technological implications. The review of [2] is broad enough, as the work carried out at Grenoble covers almost all interesting matters in the field. Some issues of interest in geophysics and astrophysics are discussed in [3]. The recently discovered liquid–liquid transition in several metals is dealt with in [4]. The fifth contribution [5] discusses the role of icosahedral superclusters in crystallization. In [6], thermodynamic calculations are carried out to identify the regions of the ternary phase diagram of Al-Cu-Y, where the formation of amorphous alloys is most probable. Experimental data and ab initio calculations are presented in [7] to show that an optimal microstructure is obtained if Mg is added to the Al-Si melt before than the modifier AlP alloy. Shock-induced melting of metals by means of laser driven compression is discussed in [8]. With respect to recent discoveries, one of the most outstanding developments is that of gallium alloys that are liquid at room temperature [9], and that, due to the oxide layer that readily cover their surface, maintain some “stiffness”. This has opened the possibility of 3D printing with liquid metals. The last article in this Special Issue [10] describes nano-liquid metals, a suspension of liquid metal and its alloy containing nanometer-sized particles. A room-temperature nano-liquid metal and its alloys were first introduced in the area of cooling high heat flux devices, which now is a commercial reality. However, their applications are not only in chip cooling, and can also be extended to waste heat recovery, kinetic energy harvesting, thermal interface material, etc. This is mainly due to properties such as low melting point, high thermal and electrical conductivity, as well as other additional physical or chemical properties. These articles are summarized in more detail hereafter [...]

Graphene/metal-oxide nanocomposites have been widely studied as anode materials for lithium ion batteries and exhibit much higher lithium storage capacity beyond their theoretical capacity through mechanisms that are still poorly understood. In this research, we present a comprehensive understanding in microscale of the discharge process of graphene/TiO2 containing surface, bulk, and interfacial lithium storage based on the first-principles total energy calculations. It is revealed that interfacial oxygen atoms play an important role on the interfacial lithium storage. The additional capacity originating from surface and interfacial lithium storage via an electrostatic capacitive mechanism contributes significantly to the electrode capacity. The research demonstrates that for nanocomposites used in energy storage materials, electrode and capacitor behavior could be optimized to develop high-performance electrode materials with the balance of storage capacity and rate.

In order to develop new Al alloy, the quasi-static and dynamic compression deformation behavior of an advanced Al-Mg alloy, which contained Zn and rare earth, were investigated. Deformed microstructures in the shear bands of this alloy were characterized by optical microscope. Results show that the compressive strengths increase with strain and strain rates being increased, and microstructures of deformed Al-Mg alloy along compression directions are sensitive to strain rates. The distorted deformation twins near the deformed band can be formed under low strain rate of 5.6×10-3 s-1, while multiple shear bands slipping can be induced by dynamic deformation under high strain rates from 1.9×103 s-1 to 5×103 s-1. Therefore, compressive strength and fracture strain of dynamic deformation are higher than that of the quasi-static deformation, which is attributed to the strain hardening and grain refining in the multiple shear bands.

Based on first-principles electronic structure calculations and molecular dynamics simulations, a possible reaction pathway for fabricating half-metallic Mo-borine sandwich molecular wires on a hydrogen-passivated Si(001) surface is presented. The molecular wire is chemically bonded to the silicon surface and is stable up to room temperature. Interestingly, the essential properties of the molecular wire are not significantly affected by the Si substrate. Furthermore, their electronic and magnetic properties are tunable by an external electric field, which allows the molecular wire to function as a molecular switch or a basic component for information storage devices, leading to applications in future molecular electronic and spintronic devices.

Bulk metallic glasses (BMGs) of Cu45Zr48-xAl7Tix with x= 0, 1.5, and 3 at.% were prepared by copper mould casting. The corrosion resistance of the BMGs with different Ti contents was examined by potentiodynamic polarization tests and weight loss measurements in 1 N NaOH, 1 N H2SO4, 1 N H2SO4 + 0.01 N NaCl and 0.5 N NaCl solutions, respectively. The newly-developed BMGs’ corrosion resistance in Cl-- or both H+ and Cl--ions containing solutions can be greatly enhanced. The influence of Ti addition on glass forming ability (GFA) and thermal stability was investigated by x-ray diffraction and differential scanning calorimetry in detail. The alloy containing 1.5 at.% Ti exhibits the largest GFA, the critical size comes up to 10 mm in diameter.

In order to obtain the directional microstructure of different supersaturation and growing velocity, three simulations is calculated with different initial temperature. When the initial temperature is 1576K, and the supersaturation and growing velocity are smaller. The average space length of columnar crystals is bigger, and the directional microstructure grows by the wide columnar crystals. Microsegregation is smaller; when the initial temperature is 1574K, the supersaturation and growing velocity increase. when the initial temperature falls to 1566K, the planar interface comes back, and microsegregation decreases rapidly. The directional microstructure grows by the thinnest columnar crystals. At the same time, the transverse solute profiles and solute boundary layer are also talked in this paper.

Phase-field method can be used to describe the complicated morphologies of crystal growth without explicitly tracking the complex phase boundaries. The conformation of volume free energy is very important for microstructure simulation with phase-field method. However, the conformation of volume free energy is still correspondingly simple and ideal at present. In this paper, a new conformation method of free energy is mentioned. Free energy of each phase at appointed states is calculated by Thermo-Calc software. In order to avoided calculation, free energy of each phase is fitted by multiple-point function according to sub- regular solution model. It is obtained that the free energy data and phase graph data of α phase, θ phase and L phase in the extension, temperature (791-841) K and component (0-35)Cu(at.%) with Al-Cu eutectic alloy. The new phase model is also founded, and used to calculate microstructure evolution of Al-Cu eutectic alloy.

In this study W was found to have strong effects on solidification structure of the binary alloy. Based 0.5 W0、W0 and 1.5W0 base W0, three conditions with free energy base W equal to 0.5 W0, W0 and 1.5W0 respectively were computed. The results showed that the variation of energy base contributed a lot to the development of side branches of equiaxed dendrite structures, the lower W, the more developed side branches, the higher W, the more restrained side branches. Furthermore, the effects of boundary layer thickness δ on solidification structures were also studied. It is found that when the layer thickness δ is as small as Δx/0.94, computational errors occurred at the base of the dendrite and when the layer thickness δ is as big as Δx/0.54, some irreal phenomena, such as coarsened dendrite trunks and maladjusted side branches, could be caused. Further study on space step Δx showed that bigger space steps made higher computational errors. It is given that the relationships among phase-field perturbation, space step and solidification structure.

In this paper, microstructure of AL-Cu eutectic alloy is simulated by improving Nestler’s multiphase-field model. The exact physical parameters are used in multiphase-field model, and obtained the steady calculational results. In this numerical calculation, AL and AL2Cu are regard as two independent components. The eutectic microstructure is regard as an admixture of single phase α (AL) and single phase θ (AL2Cu). Using the model, steady eutectic layered growth is simulated, and the simulated results agree well with the solidification theory. At the same time, the stochastic noise is introduced, and eutectic free layered growth microstructure is simulated. The microstructure of primary dendritic crystal and pseudoeutectic is also simulated by enlarging the calculational interval scale, and obtained a better result.

Maghemite (γ-Fe2O3) is a very common mineral at the earth’s surface and also an important material for making music and video tapes. Maghemite is usually synthesized from magnetite under oxidizing conditions after a few hours or a few days below a temperature of 300°C. The magnetic property of thermal instability and the chemical action after heating is an important character for maghemite. That is, it will become hematite in certain proportion after being heated above 250°C. Maghemite is therefore actually unable to have its Curie temperature measured. But late using synthetic sample, maghemite was further found partially thermal stable with a measurable Curie temperature ∼645°C. During our thermally magnetic experiments for a set of synthetic magnetite, we found that extra fined grain size (pseudo single domain (PSD) and small multi-domain (MD), mainly 1–10 μm) magnetite was formed to a completely thermally stable maghemite. This maghemite can also be produced by heating the same powder up to 700°C in an oven and keeping this temperature for 10 min, then cooling it down. When the generated maghemite by these two ways is heated from room temperature to 700°C, it shows almost fully reversible, or thermally stable. We used X-ray powder diffraction and Mossbauer spectroscopy to confirm the identity of this maghemite and compared its magnetic hysteresis, high temperature magnetization, low temperature thermal demagnetization, and low temperature susceptibility with those of the original preheated magnetite. Such quickly oxidized maghemite by heating to high temperature implies some types of maghemite formed in certain natural condition can carry a thermal remnant magnetization (TRM). Four types of maghemite were characterized and discussed according to their thermal stability. Among them, partially stable and fully thermally stable maghemite after heating should possess capability of carrying TRM. There is possibly a compensation of synthetizing maghemite between heating temperature and heating duration. The thermal stability of maghemite may be affected by a few factors, such as its purity (stoichiometry), heating temperature and duration. The grain size may be one of important factors. Maghemite might be similar to magnetite, having various magnetic properties corresponding to its grain size categories such as superparamagnetic (SP), single domain (SD) and MD. Low temperature measurement for PSD fine grain of synthetic magnetite shows a phenomenon of Verwey transition “suppressed”, its fundamental causes could be that the core diameter of oxidized magnetite is actually reach or approach SD size, so that its Verwey transition is shown “suppressed”.

Kinetic surface roughening of electrodeposited PdP and NiP amorphous films were investigated by atomic force microscopy and X-rays phase-contrast radiography. Anomalous scaling of the interface width was observed for PdP system, with H = 0.75 ± 0.06, βloc = 0.49 ± 0.07 and β = 0.38 ± 0.08. In contrast, NiP system shows normal scaling behavior, with H = 0.70 ± 0.02 and β = 0.16 ± 0.03. The results suggest that surface roughening during film growth is strongly influenced by local behaviors like hydrogen evolution reaction, which shifts surface roughening from normal scaling in NiP to anomalous scaling in PdP. Keywords: Electrodeposition, Amorphous alloys, Kinetic roughening, Synchrotron, Phase-contrast radiography, HER

Based on the theoretical analysis of the molecular dynamics simulation of sliding contact between a single micro-particle and a smooth flat surface, a new dominant mechanism of viscous flow of the amorphous layer on wafer surface for the material removal in chemical mechanical polishing (CMP) process is proposed. Furthermore, a new mathematical model characterizing the material removal rate in CMP process is developed by using micro-contact mechanics and particle size distribution theory on the basis of this mechanism. Particularly, a new important parameter k, representing the ability to remove the amorphous layer from wafer surface by a single particle, is firstly put forward and integrated in the model. The model not only incorporates the mechanical effects of the slurry particles and chemical role of the slurry, but also includes the influences of other important factors on CMP process such as wafer material properties, pad surface profiles and operating variables. The model has also been verified by the experiments shows good agreement with those experimental data in the same CMP conditions. This research will provide a new platform for further investigation in CMP mechanism of material removal.

This paper proposed a novel mathematical model to fully describe the influence of chemical mechanical synergy (CMS) on material removal in chemical mechanical polishing (CMP) of wafer at molecular scale. A general equation is derived on the basis of molecular scale removal mechanism and micro-contact theory. It is shown that the relative velocity-removal rate relation follows the trend similar to that observed from the effects of pressure and oxidizer concentration on material removal not discussed by previous models. Furthermore, the parameters of the poling pad, wafer and operating variables in CMP process that are not available in other complex models are formulated into the model. The model predictions are good agreement with the published experimental data. In addition, the present study also lends further credence to the molecular scale removal mechanism of CMP process in addition to its underlying theoretical foundation.

Rutile films were deposited on polyethylene terephatalate (PET), polytetrafluoroethylene (PTFE), Silicone, poly6-caprolactam (Nylon6), polyhexamethylene adipamide (Nylon6,6) and Nylon fiber substrates using 0.03 M TiOSO4 and 0.03 M H2O2 aqueous solution at 80°C for 24 h. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF).

Rutile films were deposited on poly-l-lactide (PLLA) substrates using 0.5 M titanium tetrachloride aqueous solution at 40 °C for 72 h. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF) within 3 days. This simple treatment provided an effective route to synthesize bioactive and biodegradable scaffolds.

In the present paper, the surface tensions and interfacial energies for pure metals and alloys for different structures were predicted by combining with the evaluated thermodynamic parameters in the framework of the CALPHAD (Calculation of Phase Diagrams) method. It is shown that the calculated results are in good agreement with the existing experimental data. On the basis of the predicted values of surface tension and interfacial energy, the phase stability and phase diagram with nano-size particles can be calculated by considering the Gibbs-Thomson equation. The calculated results for pure Fe indicate that the fcc phase is more stable with the decreasing of size of particles, which is in agreement with the experimental data reported, and the phase diagram with nano-size particle can be calculated.

The influence of large number of heating and cooling cycles on the nucleation and hence on the undercooling of Pd40Cu30Ni10P20 melt has been investigated by differential scanning calorimety. The repeated undercooling measurements allow the investigation of the stochastic nature of the nucleation process. It is found that the value of the undercooling monotonically decreases with increasing cycle number up to about 100 cycles. The melting temperature of the alloy on the other hand remains constant up to 60 cycles and then it increases by 85 °C. Structure characterisation by X-ray diffraction and scanning electron microscopy measurements reveals that a Cu-O oxide layer is gradually formed with increasing cycle number. This causes a depletion of copper in the interior of the sample and therefore decreases the glass forming ability of the alloy. A correlation of cycling dependence of melting, liquidus, and nucleation temperatures with the microstructure evolution is presented. References

Microstructural development and nanoscale compositional variations in mechanically alloyed Fe 2 O 3 -SnO 2 powders have been examined by transmission electron microscopy and energy dispersive X-ray spectrometry The mean grain size was found to stabilize around 10 nm after 19 h milling time, in close agreement with that estimated from X-ray diffraction line broadening measurements, whereas dissolution of SnO 2 grains was incomplete even after 110 h Isolated grains with the SnO 2 cassiterite structure, of diameter >10 nm, persisted up to the maximum milling time These observations are discussed in relation to previous measurements in the same system by X-ray diffraction and Mossbauer spectroscopy, which suggested that alloying on the atomic scale occurred after 110 h milling The present studies confirm that the amount of Sn dissolved in the Fe 2 O 3 hematite lattice increases with longer milling times, indicating that a supersaturated solid solution is formed, but that mixing may be locally inhomogeneous at the atomic level. Similar conclusions have been reported for studies of mechanical alloying in immiscible metallic systems The tendency for SnO 2 grains above a certain critical size to remain undissolved, while smaller grains can more easily enter into solid solution with Fe 2 O 3 , is consistent with the expected behaviour due to the increased chemical contribution to the interfacial energy with decreasing grain size Mossbauer results also showed that some of the SnO 2 had not reacted with Fe 2 O 3 after 110 h milling.

Amorphous (Zr .65 Al .075 Cu .175 Ni .1 ) 100-x Fe x (x ≤ 20) alloys have been synthesized by mechanical alloying of elemental powders. They exhibit significant supercooled liquid regions except the sample with an iron content of 20 at.%. No iron-rich cluster was detected in amorphous alloys. Alloying processes are found to be similar in three samples (x=10, 15, and 20). It is suggested that a chemical segregation starting at much lower temperature than the onset crystallization temperature could cause the observation of no supercooled liquid region in the amorphous (Zr .65 Al .075 Cu .175 Ni .1 ) 80 Fe 20 alloy.

A new structure of layered materials, layer-stacked nanorod, has been fabricated through an entirely new template-engaged structural transformation methodology. The formation of layer-stacked hexagonal tin disulfide (SnS(2)) nanorods has been demonstrated as an example by using tetragonal tin (Sn) nanorods as sacrificing templates and silica (SiO(2)) as nanoreactors. In addition, the structural transformation process probably involves the formation of orthorhombic tin sulfide (SnS) nanorods as an intermediate product. The rod-like morphology and single-crystal feature of the Sn templates are well preserved in both SnS(2) and SnS products due to the nanoscale confinement in silica. Owing to its unique structural characteristics, the SnS(2)-SiO(2) nanorod anode exhibits excellent capacity retention and improved rate capability, facilitating its application in lithium ion batteries with long cycle life and high power density.