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Textbooks have a central role in chemistry education and represent the intended chemistry curriculum at the national level. This paper focuses on analysing the intended chemistry curriculum as represented by the visual representations and the activities for students in the textbook sets in relation to the topics of the Slovenian National Chemistry Curriculum both at the primary and secondary school levels. The analysis involved all textbook sets approved by the national representatives for the 2021/2022 school year. The results revealed that in most of the curriculum topics in the analysed Slovenian chemistry textbook sets, the curriculum orientation structure of the discipline prevails and the everyday life orientation is present for both primary and secondary schools. To improve the relevance of the textbook sets for students, the currently rare presence of history of chemistry, environmental orientation, and technology and industry orientation and the lack of the use of socio-scientific orientation should be overcome. It would be valuable if further studies in textbook sets would also address the intended chemistry curriculum from a more holistic perspective. [ABSTRACT FROM AUTHOR]

The theoretical investigation of five 3,3'-(phenylmethylene)bis(1H-indole) derivatives (BIM1, BIM2, BIM3, BIM4 and BIM5) with β-cyclodextrin (β-CD) were studied using density functional theory B3LYP 3-21G method as basis set. Substituents (–OCH2COOH and -OCH3) at the ortho-, para- and meta- positions in the phenyl ring of BIMs (BIM 1–5) has changed the stability of inclusion complexes BIMs:β-CD with forming 1:1 stoichiometric ratio. To access the chemistry behind this orientation and composition, we have studied the geometrical parameters, complexation energy, HOMO-LUMO energy gap, chemical reactivity, thermodynamic parameters, Mulliken charges and molecular electrostatic potential (MEP) map for all inclusion complexes (BIMs:β-CD) with stable orientation. Natural bond orbital (NBO), NCI-RDG and QTAIM analysis revealed the prospects of hydrogen bonds (=N–H–O and –O–H–O) between BIMs and β-CD. [ABSTRACT FROM AUTHOR]

Vocational orientation is an essential aspect of teaching in school and should be fostered in chemistry teaching. This is a major challenge because stereotypes regarding gender, social class, and race exist in the field of chemistry and science. The present study examines (i) in how far future teachers are professionalized for vocational orientation for school students and (ii) the effects on future teachers of working in a project on vocational orientation in chemistry for girls with migration background (DiSenSu). Qualitative analysis of a group discussion of three future teachers reveals that their education at university fails to adequately prepare them for conceiving vocational orientation for school students. Working in the project, however, lead to a professionalization. The study shows the need for including evidence‐based education for vocational orientation for future teachers. The knowledge and materials from the project DiSenSu can serve as a basis for improving teacher education in this regard. [ABSTRACT FROM AUTHOR]

The nanoscopic structure of biodegradable choline-based naphthenic acid ionic liquids near the hexagonal boron-nitride (h-BN) surface was analyzed using quantum mechanics calculations and molecular dynamics simulations. The effects of the type of the ring (aliphatic or aromatic) and the size of the ring in the anion counterpart of the aliphatic ionic liquids (ILs) on the configurations, binding energies, orbital energies, density of states, charge transfer, and thermochemistry of adsorption of ILs on the h-BN surface were investigated. Also the significance of non-covalent interactions on the adsorption of ILs was disclosed from the quantum theory of atoms in molecule. The results of radial distribution functions, number density, and also charge density profiles showed the existence of a solid-like bottom layer in the vicinity of the surface. Angular distribution functions revealed that while the most probable orientation in aromatic anions is parallel to the h-BN sheet, the most probable orientation in aliphatic rings apparently is perpendicular to the surface. The mobility of cations and anions in the studied ILs with respect to the h-BN sheet was analyzed using their mean square displacements. For all ions near the surface, dynamics in the parallel direction were faster than those in the z-direction due to the structuring of the solid-like layer of ILs near the h-BN surface. Altogether, this study provides new insights into the physisorption of this new class of biodegradable ILs on h-BN nanosheets at the molecular level. [ABSTRACT FROM AUTHOR]

The structural and dynamic properties of water molecules in a uniformly charged nanopore have been studied using the method of classical molecular dynamics simulation. When confined in an uncharged nanopore with an appropriate radius, water molecules are aligned along the nanopore axis and form a single-file structure with the dipole vectors pointing toward the same end of the nanopore. We demonstrate here that when the nanopore is uniformly charged, the water molecules in the nanopore pack more tightly and the water molecules near the two ends of the nanopore are no longer aligned along the nanopore axis but tend to be aligned perpendicularly to the nanopore axis. The water dipole vectors do not point toward the same nanopore end. When the nanopore is positively charged, the water molecules in the nanopore align with their oxygen atoms pointing to the center of the nanopore. The central water molecule forms an L-defect. However for a negatively charged nanopore, the water molecules in the nanopore take up the opposite orientation. A D-defect is formed at the center of the nanopore. Furthermore, the water molecules in the negatively charged nanopore with moderate atomic partial charges diffuse and transport more quickly than the water molecules in an uncharged nanopore. [ABSTRACT FROM AUTHOR]

“Charge inversion” is a phenomenon in which multivalent counterions overcompensate for interfacial charges and invert the sign of the net charge near a surface. This phenomenon is believed to be relevant to biologically important processes such as DNA condensation, and hence it has attracted much attention. We investigated the polar orientation of interfacial water molecules at two different negatively charged interfaces in the absence and presence of La3+ using heterodyne-detected vibrational sum frequency generation spectroscopy, which can directly determine the up/down orientation of interfacial molecules. It was found that the orientations of water molecules at a bio-relevant phospholipid interface change from the hydrogen-up to the hydrogen-down with the addition of 10 µM La3+. This change of water orientation indicates that the net charge at the phospholipid interface is inverted by adsorption of La3+ to the phosphate headgroup. By contrast, at an alkylsulfate interface, the majority of the interfacial water molecules remain hydrogen-up orientated even in the presence of 25 mM La3+, indicating that the sulfate headgroup is still solvated by up-oriented water. The observed headgroup specificity suggests that charge inversion at the phospholipid interface originates primarily from the chemical interaction between the phosphate and La3+ ion. [ABSTRACT FROM AUTHOR]

Understanding the interaction between hydrogen (H) and helium-vacancy (He-V) complexes in tungsten (W) is important for the development of plasma-facing materials in fusion reactors. H trapping by HexVy complexes in bulk W, as well as the H solution behavior and H trapping by HexV complexes near W(100), W(111), and W(110) surfaces, has been investigated by first-principles computer simulations using density function theory. The results show that the sequential H binding energies to HexV complexes in bulk W decrease with the increasing number of H and He. For the HexV2 complexes in bulk W, H prefers to trap at interstitial sites near the junction of the di-vacancy, where the H can minimize the isosurface of optimal charge density. The most stable interstitial sites for H below W surfaces are dependent on the surface orientation. Our calculations indicate that H atoms tend to prefer a depth of 0.3 nm below the W(100) and W(111) surfaces due to the surface reconstruction. The binding energy of H to a HeV complex near W surfaces has the most significant orientation dependence below the W(111) surface, followed by the W(100) and W(110) surfaces. Compared with the bulk value, the largest difference in the average binding energy of H to the stable HexV complexes at the three W surfaces is about 0.2 eV. Furthermore, the effect of surfaces on the H binding energy to HexV complexes can be ignored for depths greater than 0.65 nm. [ABSTRACT FROM AUTHOR]

Density function theory calculations have been performed to study the stability of small helium-vacancy (He-V) complexes near tungsten (W) surfaces of different orientations. The results show that the stability of vacancies and He-V complexes near W surfaces depends on surface orientation. However, as the depth below the surface increased beyond about 0.65–0.8 nm, the stability of He-V complexes is similar to the bulk. The formation energies of single vacancies and di-vacancies at depths less than 0.2 nm below the W(110) surface are higher than for W(100) or W(111) surfaces, but have lower energies at depths between 0.2 and 0.65 nm. The formation energies of He-V complexes below W surfaces are sensitive to the geometric orientation of the He and vacancy, especially below the W(111) surface. Within about 0.2 nm of the top layer of the three W surfaces, neither a vacancy nor a di-vacancy can trap He. Because of the lower formation energy of He-V complexes and higher He binding energy to vacancies below the W(110) surface, the He desorption from the W(110) surface is less likely to occur than from the W(100) and W(111) surfaces. Our results provide fundamental insight into the differences in surface morphology changes observed in single W crystals with different surface orientations under He plasma exposure. [ABSTRACT FROM AUTHOR]

Surprisingly long-ranged intermolecular correlations begin to appear in isotropic (orientationally disordered) phases of liquid crystal forming molecules when the temperature or density starts to close in on the boundary with the nematic (ordered) phase. Indeed, the presence of slowly relaxing, strongly orientationally correlated, sets of molecules under putatively disordered conditions (“pseudo-nematic domains”) has been apparent for some time from light-scattering and optical-Kerr experiments. Still, a fully microscopic characterization of these domains has been lacking. We illustrate in this paper how pseudo-nematic domains can be studied in even relatively small computer simulations by looking for order-parameter tensor fluctuations much larger than one would expect from random matrix theory. To develop this idea, we show that random matrix theory offers an exact description of how the probability distribution for liquid-crystal order parameter tensors converges to its macroscopic-system limit. We then illustrate how domain properties can be inferred from finite-size-induced deviations from these random matrix predictions. A straightforward generalization of time-independent random matrix theory also allows us to prove that the analogous random matrix predictions for the time dependence of the order-parameter tensor are similarly exact in the macroscopic limit, and that relaxation behavior of the domains can be seen in the breakdown of the finite-size scaling required by that random-matrix theory. [ABSTRACT FROM AUTHOR]

Structural and dynamical properties of interfacial water molecules near a hexagonal boron nitride sheet (h-BN) are investigated by means of Born-Oppenheimer molecular dynamics simulations. Orientational profiles in the interfacial regions reveal two distinct types of water molecules near the BN surface. Depending on the positions of the water molecules, on top of either N or B atoms, one type contains water molecules that are oriented with one OH bond pointing toward the N atoms and the other type contains water molecules that remain parallel to the BN sheet. Distinct hydrogen bonding and stabilization energies of these two types of water molecules are found from our calculations. In order to see the effects of dispersion interactions, simulations are performed with the BLYP (Becke-Lee-Yang-Parr) functional and also BLYP with Grimme's D3 corrections (BLYPD3). An enhancement of water ordering near the surface is observed with the inclusion of dispersion corrections. Further analysis of the diffusion coefficients, rotational time correlation functions, and hydrogen bond dynamics shows that water molecules near the h-BN sheet move faster compared to bulk water molecules both translationally and rotationally. The water molecules in the first layer are found to show substantial lateral diffusion. The escape dynamics of water from the solvation layer at the BN surface is also looked at in the current study. We have also investigated some of the electronic properties of interfacial water such as the charge density and dipole moment. It is found that the water molecules at the surface of the BN sheet have a lower dipole moment than bulk molecules. [ABSTRACT FROM AUTHOR]

An important initial step in the combustion of gasoline and diesel fuels is the abstraction of hydrogen from alkylbenzenes to form resonance-stabilized alkyl benzyl radicals. This work uses, for the first time, double resonance spectroscopy methods to explore the conformation-specific vibronic and infrared spectroscopy of the a-ethylbenzyl (αEtBz) and α-propylbenzyl (αPrBz) radicals. Local mode Hamiltonian modeling enables assignment of the alkyl CH stretch IR spectra, accounting for Fermi resonance that complicates aliphatic alkyl CH stretch IR spectroscopy. The ground state conformational preferences of the ethyl and propyl chains are changed from those in the alkylbenzenes themselves, with global minima occurring for an in-plane orientation of the alkyl chain (trans) about its first dihedral angle (Φƒ123, numbers are alkyl C atoms. C1 is CH radical site). This in-plane structure is the only observed conformer for the α-EtBz radical, while two conformers, tt and tg' share this orientation at the first dihedral, but differ in the second (Φ1234) for the αPrBz radical. The in-plane orientation lowers the local site frequencies of the CH2 group stretches immediately adjacent to the benzylic radical site by about 50 cm-1 relative to those in pure alkyl chains or alkylbenzenes. This effect of the radical site is localized on the first CH2 group, with little effect on subsequent members of the alkyl chain. In the D1 excited electronic state, an out-of-plane orientation is preferred for the alkyl chains, leading to torsional mode Franck-Condon activity in the D0-D1 spectra that is both conformer-specific and diagnostic of the conformational change. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of chain-branching effects, essential for establishing general knowledge of the structure-property-phenomenon relationship in polymer science, has not yet been found, due to a critical lack of knowledge on the role of short-chain branches, the effects of which have mostly been neglected in favor of the standard entropic-based concepts of long polymers. Here, we show a significant effect of short-chain branching on the structural and dynamical properties of polymeric materials, and reveal the molecular origins behind the fundamental role of short branches, via atomistic nonequilibrium molecular dynamics and mesoscopic Brownian dynamics by systematically varying the strength of the mobility of short branches. We demonstrate that the fast random Brownian kinetics inherent to short branches plays a key role in governing the overall structure and dynamics of polymers, leading to a compact molecular structure and, under external fields, to a lesser degree of structural deformation of polymer, to a reduced shear-thinning behavior, and to a smaller elastic stress, compared with their linear analogues. Their fast dynamical nature being unaffected by practical flow fields owing to their very short characteristic time scale, short branches would substantially influence (i.e., facilitate) the overall relaxation behavior of polymeric materials under various flowing conditions. [ABSTRACT FROM AUTHOR]

Enhanced kinetic stability of vapor-deposited glasses has been established for a variety of glass organic formers. Several recent reports indicate that vapor-deposited glasses can be orientationally anisotropic. In this work, we present results of extensive molecular simulations that mimic a number of features of the experimental vapor deposition process. The simulations are performed on a generic coarse-grained model and an all-atom representation of N,N'-bis(3-methylphenyl)-N,N'- diphenylbenzidine (TPD), a small organic molecule whose vapor-deposited glasses exhibit considerable orientational anisotropy. The coarse-grained model adopted here is found to reproduce several key aspects reported in experiments. In particular, the molecular orientation of vapor-deposited glasses is observed to depend on substrate temperature during deposition. For a fixed deposition rate, the molecular orientation in the glasses changes from isotropic, at the glass transition temperature, Tg, to slightly normal to the substrate at temperatures just below Tg. Well below Tg, molecular orientation becomes predominantly parallel to the substrate. The all-atom model is used to confirm some of the equilibrium structural features of TPD interfaces that arise above the glass transition temperature. We discuss a mechanism based on distinct orientations observed at equilibrium near the surface of the film, which get trapped within the film during the non-equilibrium process of vapor deposition. [ABSTRACT FROM AUTHOR]

Previous methods for determining whether a uniform region of a sample is crystalline or isotropic-- what we call the "state of internal orientation" S--require a priori knowledge of properties of the purely crystalline and purely isotropic states. In addition, these methods can be ambiguous in their determination of state S for particular materials and, for a given material, the spectral methods can be ambiguous when using particular peaks. Using first-principles Raman theory, we have discovered a simple, non-resonance, polarized Raman method for determining the state S that requires no information a priori and will work unambiguously for any material using any vibrational mode. Similar to the concept behind "magic angle spinning" in NMR, we have found that for a special set of incident/analyzed polarizations and scattering angle, the dependence of the Raman modulation depth M on the sample composition--and, for crystalline regions, the unit cell orientation--falls out completely, leaving dependence on only whether the region is crystalline (M = 1) or isotropic (M = 0). Further, upon scanning between homogeneous regions or domains within a heterogeneous sample, our signal M is a clear detector of the region boundaries, so that when combined with methods for determining the orientations of the crystalline domains, our method can be used to completely characterize the molecular structure of an entire heterogeneous sample to a very high certainty. Interestingly, our method can also be used to determine when a given mode is vibrationally degenerate. While simulations on realistic terthiophene systems are included to illustrate our findings, our method should apply to any type of material, including thin films, molecular crystals, and semiconductors. Finally, our discovery of these relationships required derivations of Raman intensity formulas that are at least as general as any we have found, and herein we present our comprehensive formulas for both the crystalline and isotropic states. [ABSTRACT FROM AUTHOR]

Strong short-range intermolecular interactions result in position and orientation correlations between nearest neighbour molecules in isotropic liquids, but it is generally assumed that such correlations extend at most a few molecular diameters. Results from second-harmonic light scattering experiments presented here reveal long-range molecular orientation correlations in liquid water, where the molecular dipole orientation distribution has the form of a nearly pure transverse vector field. Spatial scales in the range 200-2000 nm are probed by the angle-dependent measurements and the observed correlations are thought to result from rotation-translation coupling in acoustic phonons in the liquid. [ABSTRACT FROM AUTHOR]

Water interfacing hydrated proteins carry properties distinct from those of the bulk and is often described as a separate entity, a "biological water." We address here the question of which dynamical and structural properties of hydration water deserve this distinction. The study focuses on different aspects of the density and orientational fluctuations of hydration water and the ability to separate them experimentally by combining depolarized light scattering with dielectric spectroscopy. We show that the dynamics of the density fluctuations of the hydration shells reflect the coupled dynamics of the solute and solvent and do not require a special distinction as "biological water." The orientations of shell water molecules carry dramatically different physics and do require a separation into a sub-ensemble. Depending on the property considered, the perturbation of water's orientational structure induced by the protein propagates 3-5 hydration shells into the bulk at normal temperature. [ABSTRACT FROM AUTHOR]

By simulating the rigid simple point charge extended model at temperature T = 300 K, the orientational relaxation of the OH-bond in water was investigated over short to intermediate timescales, within which molecules undergo inertial rotation and libration and then enter the rotational diffusion regime. According to the second-cumulant approximation, the orientational time correlation function (TCF) of each axis that is parallel or perpendicular to an OH-bond is related to an effective rotational density of states (DOS), which is determined using the power spectra of angular velocity autocorrelation functions (AVAFs) of the other two axes. In addition, the AVAF power spectrum of an axis was approximated as the rotational stable instantaneous normal mode (INM) spectrum of the axis. As described in a previous study [S. L. Chang, T. M. Wu, and C. Y. Mou, J. Chem. Phys. 121, 3605 (2004)], simulated molecules were classified into subensembles, according to either the local structures or the H-bond configurations of the molecules. For global molecules and the classified subensembles, the simulation results for the first- and second-rank orientational TCFs were compared with the second-cumulant predictions obtained using the effective rotational DOSs and the rotational stable- INM spectra. On short timescales, the OH-bond in water behaves similar to an inertial rotor and its anisotropy is lower than that of a water molecule. For molecules with three or more H-bonds, the OH-bond orientational TCFs are characterized by a recurrence, which is an indication for libration of the OH-bond. The recurrence can generally be described by the second-cumulant prediction obtained using the rotational stable-INM spectra; however, the orientational TCFs after the recurrence switch to a behavior similar to that predicted using the AVAF power spectra. By contrast, the OH-bond orientational TCFs of molecules initially connected with one or two H-bonds decay monotonically or exhibit a weak recurrence, indicating rapid relaxation into the rotational diffusion regime after the initial Gaussian decay. In addition to accurately describing the Gaussian decay, the second-cumulant predictions formulated using the rotational stable-INM spectra and the AVAF power spectra serve as the upper and lower limits, respectively, for the OH-bond orientational TCFs of these molecules after the Gaussian decay. [ABSTRACT FROM AUTHOR]

The technique of recoil ion momentum spectroscopy is employed to determine the complete momentum vectors for three fragment dissociation channels, [D2O](q+2) → (D+ + D+ + Oq+) with q = 1, 2, or 3 formed in collisions of isolated water molecules with 450 keV Xe9+ ions. The kinetic energy released in each of these dissociation channels is measured and angular correlations between the fragment momenta are determined. From the angular correlations of the three fragment ions with the direction of the incoming beam, a strong anisotropy in the emission of recoil fragments is reported. It is inferred that the molecular plane prefers to lie orthogonal to the incoming beam direction with certain orientations being more preferred than others and a clear signature of non-coplanar dissociation is also observed. [ABSTRACT FROM AUTHOR]

The recently developed evolutionary algorithm USPEX proved to be a tool that enables accurate and reliable prediction of structures. Here we extend this method to predict the crystal structure of polymers by constrained evolutionary search, where each monomeric unit is treated as a building block with fixed connectivity. This greatly reduces the search space and allows the initial structure generation with different sequences and packings of these blocks. The new constrained evolutionary algorithm is successfully tested and validated on a diverse range of experimentally known polymers, namely, polyethylene, polyacetylene, poly(glycolic acid), poly(vinyl chloride), poly(oxymethylene), poly(phenylene oxide), and poly (p-phenylene sulfide). By fixing the orientation of polymeric chains, this method can be further extended to predict the structures of complex linear polymers, such as all polymorphs of poly(vinylidene fluoride), nylon-6 and cellulose. The excellent agreement be-tween predicted crystal structures and experimentally known structures assures a major role of this approach in the efficient design of the future polymeric materials. [ABSTRACT FROM AUTHOR]

Measurements of the polarization dependence of hyper-Rayleigh scattering (HRS) by solutions of p-nitroaniline (PNA) in acetone-d6 were used to study molecular orientation correlations. The HRS observations were analyzed in terms of short range direct dipole-dipole correlations between the PNA molecules, a long range transverse polar mode for the PNA molecules, and a long range ion-induced longitudinal polar mode. The conclusion that long range correlations are present is opposite to that in previous work, due to previous neglect of the ion-induced contribution. Depolarized HRS not explained by local correlations appears above 0.1 M PNA concentration, and analysis of the HRS observations indicates strong orientation correlations with a range of 10 nm for the PNA molecules. [ABSTRACT FROM AUTHOR]

A carbon fiber-epoxy composite (CFEC) shock response in the through thickness orientation and in one of the fiber directions is significantly different. The hydrostatic pressure inside anisotropic materials depends on deviatoric strain components as well as volumetric strain. Non-linear effects, such as shock effects, can be incorporated through the volumetric straining in the material. Thus, a new basis is required to couple the anisotropic material stiffness and strength with anisotropic shock effects, associated energy dependence, and damage softening process. This article presents these constitutive equations for shock wave modeling of a damageable carbon fiber-epoxy composite. Modeling the effect of fiber orientation on the shock response of a CFEC has been performed using a generalized decomposition of the stress tensor [A. A. Lukyanov, Int. J. Plast. 24, 140 (2008)] and Mie-Grüneisen's extrapolation of high-pressure shock Hugoniot states to other thermodynamics states for shocked CFEC materials. The three-wave structure (non-linear anisotropic, fracture, and isotropic elastic waves) that accompanies damage softening process is also proposed in this work for describing CFEC behavior under shock loading which allows to remove any discontinuities observed in the linear case for relation between shock velocities and particle velocities [A. A. Lukyanov, Eur. Phys. J. B 74, 35 (2010)]. Different Hugoniot stress levels are obtained when the material is impacted in different directions; their good agreement with the experiment demonstrates that the anisotropic equation of state, strength, and damage model are adequate for the simulation of shock wave propagation within damageable CFEC material. Remarkably, in the through thickness orientation, the material behaves similar to a simple polymer whereas in the fiber direction, the proposed in this paper model explains an initial ramp, before at sufficiently high stresses, and a much faster rising shock above it. The numerical results for shock wave modeling using proposed constitutive equations are presented, discussed, and future studies are outlined. [ABSTRACT FROM AUTHOR]

CeO 2 nanocubes with (100) surface orientation are successfully synthesized and found to facilitate the sinterability of CeO 2 material. The CeO 2 nanocubes show a much-improved sinterability relative to CeO 2 nanoparticles prepared by the conventional citric-nitrate method. The nanocubes can be successfully sintered at a relatively low temperature of 1200 °C without using any sintering aids. In contrast, a pellet using conventional CeO 2 nano-powder obtained from the conventional citric-nitrate method can be densified only after sintering at 1400 °C, which is 200 °C higher than that for the CeO 2 nanocube sintering, although the starting particle size of both CeO 2 samples is similar. Density functional theory indicates that the surface energy of the (100) plane is significantly higher than that of the (111) plane, which is the more typical surface presentation of conventional CeO 2 particles. This high surface energy allows fast growth of the CeO 2 nanocubes during sintering, contributing to their improved sinterability. [ABSTRACT FROM AUTHOR]

Particle packing and orientation in Ceramic Injection Moulding are caused by shear rate variations along the part, which are complicated by cooling rates and depend on material properties and process parameters. This work studies particle orientation and packing for a ceramic feedstock in relation to mould temperature, with a focus on the influence from Rapid Heat Cycle Moulding (RHCM). A sample part consisting of bars having different thicknesses (0.4 mm to 6 mm) was injection moulded using first ambient mould temperature and then a rapid heating approach; subsequently, green part microstructure was analysed to detect particle orientation and packing. Results show a more uniform orientation at thick sections using RHCM, with a 15% enlargement of a core layer characterised by randomly oriented particles, as well as a higher homogeneity of powder packing between thin and thick sections. Thus, this study demonstrates that not only can RHCM be used to enhance feature replication capability, but also has the potential to improve critical microstructural properties of green components, which highly influence sintered parts quality. [ABSTRACT FROM AUTHOR]

For the Al-alloyed 9Cr-ODS steels consolidated by spark plasma sintering and annealed at 800 °C, the Y-Al-O oxides, interface structure and orientation relationships between the oxides and the matrix are studied by high-resolution transmission electron microscope technique. It is found that the spark plasma sintering can serve as a useful and effective tool to investigate the transition states in complex oxide formation. Monoclinic Y4Al2O9 (YAM), orthorhombic YAlO3 (YAP), cubic Y3Al5O12 (YAG) and Y2O3 nanoparticles are identified. Both YAM and YAG can directly precipitate from the Y2O3 particles. One individual Y2O3 particle will produce several YAM particles, while only one YAG particle can be formed within one Y2O3 particle. The majority of identified Y-Al-O oxides exhibit partially coherent interfaces with the matrix, and multiple orientation relationships are revealed. [ABSTRACT FROM AUTHOR]

Abstract Dislocations originating from the seed junctions are the most harmful defects in quasi-single crystalline silicon (QSC-Si). In traditional <100>-oriented QSC-Si ingots, dislocations easily develop into cascade shape, or even further form sub-grain boundaries as the ingot grows. In this paper, we have developed a novel <110>-oriented QSC-Si ingot to control the gliding and propagation of dislocations. It is found that the cascade shape is absent and dislocations only aggregate in the {100}/{100} boundary planes of <110>-oriented seeds, revealed by the minority carrier lifetime mapping and photoluminescence image. Accordingly, the internal quantum efficiency of <110>-oriented QSC-Si solar cells is obviously higher than that of the traditional <100>-oriented ones. Nevertheless, it should be noticed that the average photoelectric conversion efficiency of <110>-oriented QSC-Si solar cells could be 0.6% lower than that of traditional ones if the {100}/{100} boundary is included in the solar cell, due to a higher reverse leakage current. This problem can be involved by enlarging the size of seed crystals or adopting better seed arrangement. These results provide a new promising method for the development of high quality QSC-Si in photovoltaic industry. Highlights • The quasi-single crystalline silicon is grown by using <110>-oriented seeds. • The dislocations originating from the seed junctions are confined at the junctions of the {100}/{100} boundary plane. • The gliding and propagation of dislocations in the <110>-oriented QSC-Si ingot are completely controlled. • The average minority carrier lifetime of the <110>-oriented QSC-Si ingot is significantly increased. [ABSTRACT FROM AUTHOR]

Abstract Precipitation and dissolution of γNb 5 Si 3 precipitates in an Nb-Ti-Si based alloy has been visualized by atomic-scale in-situ heating transmission electron microscopy. Nanoscale γNb 5 Si 3 precipitates nucleate inside Nbss around 850 °C with two orientation relationships (ORs): (200) Nb // 1 1 ¯ 00 γ (OR-I) and 10 1 ¯ Nb // 1 1 ¯ 00 γ (OR-II). Growth and dissolution of the two orientational γNb 5 Si 3 precipitates are promoted by motion of atomic steps and facets at interfaces. Precipitates along OR-I is less stable than that of OR-II, adopting dissolution temperature of 1125 °C and 1250 °C respectively. The orientational stability of γNb 5 Si 3 precipitates, which is correlated with planar disregistry, affects their evolution behavior directly upon heating. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Highlights • CHF (Critical Heat Flux) decreases with the heated surface orientation. • Vapor behaviors prior to CHF can be characterized into three regions. • Bubbles generated from the vertical surface were drifted upward freely. • Bubbles generated from the heater facing downward were forced upward. • Bubbles generated from the horizontal facing downward were remained on the heated surface. Abstract A visualization study on boiling phenomena at various surface orientations was conducted to investigate the bubble behaviors and the critical heat flux (CHF) mechanism. The vapor behavior observed in this study indicates that the pool boiling can be categorized into three regions: upward facing (0° ≤ θ < 90°), vertical and near-downward facing (90° ≤ θ ≤ 165°), and downward facing (165° < θ ≤ 180°). In the upward-facing region, the vapor was generated and detached easily in the vertical direction of the heated surface. In the vertical and near-downward facing region, the vapor grew and drifted upward the surface in a wavy shape owing to the vapor flow. When the heater faced downward (165° < θ ≤ 180°), the vapor was trapped and blanketed the entire heated surface. According to the vapor behaviors at various inclination angles, the CHF decreased with the increase of the surface orientation from horizontal facing upward to downward. The vapor film thickness decreased as the surface orientation increased from 0° to 180°. The vapor velocity affected the distance between the two wavelength peaks of the vapor. Faster vapor flow yielded a shorter wavelength. Additionally, the CHF location was affected by the surface orientation owing to the vapor behavior. These results indicate that the surface orientation significantly affects the vapor behavior, CHF, CHF location, vapor velocity, wavelength, and maximum and minimum vapor thicknesses on a printed circuit board in a saturated water pool. [ABSTRACT FROM AUTHOR]

Abstract In this work, we report a simple strategy to improve the detection sensitivity as well as the spectral quality of probe molecules on surface-enhanced Raman scattering (SERS) substrates. On normal SERS substrates, due to the decreased absorption capacity and changes in the molecule orientations, SERS signals disappear when the analyte molecule concentrations reach a limit value. To solve this problem, the molecular template reagent (MTR) technique, a simple strategy based on SERS surface selection rules, is considered. By choosing the best MTR according to different samples, the effect of adjusting the molecular orientations of samples can be studied. In this process, 1-butanethiol, 1-hexanethiol, 1-octanethiol, 1-decanethiol, and 1-dodecanethiol, which are MTRs, are used to adjust the orientations of probe molecules under optimized conditions. The use of the MTR technique indicated that the limit of detection (LOD) of the probe molecules of p-aminobenzenethiol and 4-mercaptobenzoic acid on noble metal substrates showed an increase of one order of magnitude over the LOD of the pure probing molecule systems. Hence, the proposed method introduces a way to detect the molecules with an improved sensitivity at extremely low concentrations. The study corresponds to a proof-of-concept study of MTR-assisted SERS for SERS-based applications in ultrasensitive analyses. Graphical abstract fx1 Highlights • A novel strategy to improve sensitivity of probe molecules. • Regulate target probe molecules into preferred orientations by molecular template reagent (MTR). • The use of MTR technique indicated that the LOD of the probe molecules of p-aminobenzenethiol exhibited one order of magnitudes increased. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • DFT has been used to investigate dehydrogenation of octahydroindole on Pt (1 1 1) surface. • Octahydroindole dehydrogenation to indole is favorable with(out) indoline as an intermediate. • Molecule orientation on Pt (1 1 1) surface has a strong influences on calculated system properties. Abstract Ab initio calculations based on dispersion-corrected density functional theory were used to gain insight into the adsorption properties of reactants and products involved in the catalytic dehydrogenation of octahydroindole on a Pt (1 1 1) surface. Octahydroindole is the hydrogen-rich form of a liquid organic hydrogen carrier (LOHC); indole is the hydrogen-lean form of the LOHC, and indoline is a possible dehydrogenation intermediate of the LOHC. The adsorption of octahydroindole, indoline, and indole on a Pt (1 1 1) surface were found to be energetically favored. Dehydrogenation of octahydroindole proceeded by the systematic removal of H 2 molecules along different dehydrogenation reaction paths. Investigation of these paths revealed that dehydrogenation of octahydroindole to indole can take place with or without indoline as intermediate. This observation was consistent with experimental results. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The inversion of the laser intensity profile by polarization control was demonstrated. • Detailed theoretical and experimental analysis of the formed profiles are performed. • The pillar formation using the inverted interference intensity profile was shown. • The growth of the pillar with additional laser pulses was demonstrated. • The mechanism of the structures formations is discussed in details. Abstract Three-beam laser interference patterning, with the ability to control the polarization of each beam, is used to produce crater and pillar like periodic structures on steel surfaces. The experiments are performed using parallel and radial polarization vector orientations of the interfering beams. In case of parallel vector orientation, common intensity profiles consisting of intensity peaks distributed in triangle lattice geometry are formed. By changing the polarization to the radial set, the intensity distribution of the interference pattern could be inverted while the geometry also has a triangle lattice shape. The equations describing both intensity profiles are derived from the basic interference equation and the modeled interference intensity profiles are compared with measured intensity profiles. Two different types of structures containing periodically distributed craters and pillars are produced using these polarization sets. Using a detailed analysis of the scanning electron microscope images and confocal data, the mechanisms responsible of the formation of the pillar- and crater-like geometries are introduced. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Iron oxide nanowires are fabricated by PLD in the presence of magnetic field. • The ambient gas and its pressure strongly influence the nanowires characteristics. • Nanowires produced in open air are aligned along the magnetic field lines. • The density of the nanowires decreases with the increase of the target-substrate distance. • The nanowires show hysteresis with values of the coercive field of ∼500 Oe at 5 K. Abstract This paper presents an experimental investigation on laser-assisted fabrication of oriented nanowires composed by magnetic nanoparticles. The nanowires were produced by implementation of pulsed laser deposition in presence of a magnetic field. The application of an external magnetic field led to the formation of nanowires with a length of several micrometers whose orientation is influenced by the direction of the magnetic field lines. The influence of the type of ambient gas and its pressure on morphology and phase composition of the deposited samples was investigated. It was found that the ambient gas has direct influence on both the degree of orientation and the phase composition of the nanowires. SEM analysis of samples deposited at different target-substrate distances showed that the density of the nanowires decreases with the increase of the distance. A preliminary result on the magnetic properties of the produced nanowires is also reported. [ABSTRACT FROM AUTHOR]

Highlights • Ga 2 O 3 film with (2 ¯ 0 1) preferred orientation was sputtered on SiC crystal substrate. • After annealing at 800 °C, Ga 2 O 3 film has better crystalline quality (FWHM = 0.108°). • Based on the facile Ga 2 O 3 film, MSM deep-ultraviolet detector was fabricated. • Its responsitvity and detectivity reach 2.6 A/W and 1.6 × 1012 Jones, respectively. • The detector shows fast response characteristics with the response time of 0.26 s. Abstract As a wide-bandgap semiconductor oxide material, Ga 2 O 3 has great application prospects in various optoelectronic fields. At present, much attention has been paid to Ga 2 O 3 deep ultraviolet (DUV) detectors, in which Ga 2 O 3 films are often poor-quality poly-crystalline or expensive mono-crystalline. In this paper, Ga 2 O 3 films with highly preferred orientation were deposited on hexagonal SiC (6H-SiC) substrate by magnetron sputtering, and the as-prepared Ga 2 O 3 films were then annealed. The influences of sputtering and annealing parameters on Ga 2 O 3 films were analyzed. Finally, DUV photo-detectors based on the as-obtained Ga 2 O 3 films were fabricated. The experimental results show, when choosing optimal sputtering parameters (RF power: 120 W, gas pressure: 1.5 Pa, film thickness: 400 nm), the sputtered Ga 2 O 3 films with (2 ¯ 0 1) highly preferred orientation after annealing at 800 °C, have good crystalline quality (FWHM = 0.108°) between single-crystal and polycrystal, showing good compromise between optoelectronic characteristics and preparation cost. The fabricated metal-semiconductor-metal (MSM) DUV photodetector operated at a bias voltage of 10 V can achieve excellent comprehensive photo-detection properties for 254 nm ultraviolet light: the responsivity, detectivity and quantum efficiency are high as 2.6 A/W, 1.6 × 1012 Jones and 1265%, respectively, along with short response time of 0.26 s. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Staged evolution of dislocation structure in Ti crystallite subjected to scratching. • Mechanical response of Ti crystallites is governed by material fragmentation ahead of indenter. • Grain boundaries provide to rotational deformation and fragmentation of the material. Abstract Atomic scale deformation mechanisms of Ti single- and bicrystals subjected to scratch testing were studied experimentally and using molecular dynamics simulation. The numerical model explicitly considers the crystallographic orientation of Ti crystallites experimentally determined from EBSD analysis. The stage character of the evolution of dislocation structure in the Ti crystallites under loading was revealed that resulted from fragmentation of the material in the scratch groove. When the direction of easy dislocation glide is close to the scratching direction, the stages of generation and movement of dislocations alternate with the stages of dislocation pinning. It was found experimentally that the initially softer grain was characterized by a shallower residual scratch depth than the originally harder one. MD simulation revealed that the fragmentation is an origin of the observed disagreement between the residual scratch depth and the initial hardness of Ti grains with different crystallographic orientations. Grain boundaries were shown not only to be barriers for dislocation glide but also to favor the development of rotational deformation and further fragmentation of the material in the scratch groove. [ABSTRACT FROM AUTHOR]

Highlights • Non-radiative patterns near surface holes and bumps are inversed. • Far-field maxima and minima positions are inversed for holes and bumps. • Interference maxima have opposite orientation on glass and metal surfaces. • Interference maxima qualitatively differ for holes and voids close to surface. • Less pronounced patterns for short pulses with finite spectral bandwidth. • Asymmetric shape may switch the absorbed energy maxima positions. • Multiple holes and bumps generate joint interference patterns on the surface. Abstract This paper deals with a numerical investigation of the energy deposition induced by ultrafast laser interaction with nanostructures. We calculate and analyze the intensity near-field reactive and radiative patterns resulted from the interference of the incident light with light scattered by individual subwavelength holes and bumps on the surface of metallic and dielectric materials. The role of light polarization, optical material properties, collective effects and nature of the imperfections in localized energy absorption is elucidated. The results open new perspectives in precise light manipulation by surface inhomogeneities and well-controlled surface nanostructuring by ultrashort laser. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Migration mechanisms of interphase boundaries (IPBs) are essential for understanding solid phase transformations. Most studies of the migration mechanisms of IPBs are focused on transformations under rational or near-rational orientation relationships. However, for cases of irrational orientation relationships that widely exist in massive transformations and grain boundary (GB) precipitations, knowledge remains extremely lacking. In this study, taking a triangular-square massive transformation as an example, we explored the migration mechanisms of IPBs with irrational orientation relationships at atomic scales by using the phase-field crystal method. Crystallography analysis based on near-coincidence site calculations also were conducted to verify simulated IPBs structures. Both massive transformations and precipitation transformations were reproduced using the phase-field crystal model. The simulation results show that, similar to the case of rational orientation relationships, the IPBs with irrational orientation relationships migrate by a ledge mechanism due to the satisfying of the edge-to-edge matching relationship. Further simulations on the interactions between IPBs and GBs indicate that GBs can make the newly generated massive phase change its orientation during the process of massive phase transfer across some low-angle GBs. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Controlling the orientation of crystal grains in metal additive manufacturing is an active field of research. Assuming that three-dimensional control of orthotropic metal crystal grain can be achieved, we numerically studied the effective performance of a topology-optimized lattice made of crystal grains with optimal directions in orientation. The objective function is maximized for an effective isotropic stiffness. The effective properties of the lattice are calculated using the homogenization method. Each discretized finite element is regarded as a crystal grain and its artificial density and orientation are optimized. Through several numerical studies using a single orthotropic crystal of Ni exhibiting large anisotropy in its single crystal stiffness, the optimization and the usefulness of the lattice structure composed of optimal orientation crystal grains is confirmed. In the design of a lattice with effective isotropic stiffness, an improvement in stiffness was observed compared with that using equivalent isotropic Ni as a material. [ABSTRACT FROM AUTHOR]

Highlights • A new dislocation density based crystal plasticity model is developed. • The effect of grain orientation distribution on ductility shows opposite trends. • The findings provide an insight into the strength-ductility synergy. Abstract Polycrystalline metal with well-designed grain structure exhibits different strength and ductility compared with the conventional macro scale materials. In the present study, the mechanisms of strain hardening and inhomogeneous deformation in polycrystals are analyzed by considering the interaction between dislocations and grain boundaries. Firstly, a dislocation density based crystal plasticity model is developed and then used to quantitatively study the grain size and orientation effects in polycrystals. With the decrease of grain size, the accumulation and interaction of dislocations are promoted in the grain, resulting in back-stress hardening. Simultaneously, two opposite effects of the inhomogeneity in grain orientation are obtained by evaluating the local Schmidt factors in each grain and their standard deviation. The findings highlight the effect of grain boundary on the strength and provide quantitative insight into the effect of grain orientation on ductility. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Patterned arrays of nanoholes and nanorings were prepared using colloidal lithography combined with steps of solution immersion and vapor deposition of organosilanes. Samples prepared with colloidal lithography exhibit millions of reproducible test structures with a periodic arrangement throughout areas of the surface according to the dimensions and spacing of the particle mask. Views of the size and morphology of nanopatterns obtained with atomic force microscopy (AFM) can provide information of progressive steps of chemical reactions as nanostructures are grown within spatially confined areas surrounded by a resist film. A surface mask of colloidal latex or silica spheres was used to protect discrete areas of a Si(111) substrate from the deposition of organosilanes. When the mask was removed, the uncovered areas of the surface revealed regularly-shaped, small sites of uncovered substrate available for further reaction steps to build hierarchical surface structures. Nanostructures of zinc phthalocyanines (ZnPcs) were constructed using amine-terminated nanopatterns as sites for binding. Spatial selectivity was achieved for directing the attachment of ZnPcs to the surface using resist films of 2-methoxy(polyethyleneoxy)propyl]trichlorosilane (PEO-silane) and also with octadecyltrimethoxysilane (OTMS). The molecule chosen as a linker was (3-aminopropyl)triethoxysilane (APTES) which presents an amine group at the interface. In general, phthalocyanine molecules tend to bind in a coplanar orientation by physisorption to the surface and can stack together through pi-pi interactions between adjacent macrocycles. However, the nature of the substituents will also influence whether the molecules assemble on surfaces in a side-on orientation or with the macrocycle oriented in a coplanar arrangement. Hydroxyl and isothiocyanate pendant groups were attached to the macrocycles of ZnPcs chosen for this study, to investigate conformational differences when attached to APTES nanopatterns. The size and morphology of nanostructures was visualized and sensitively measured with tapping-mode AFM. The elastic response of samples patterned with ZnPc was mapped with force modulation AFM. Changes in the height of nanostructures indicate whether the macrocycles are oriented upright or parallel to the surface plane, or if multilayers were formed. [ABSTRACT FROM AUTHOR]

Abstracts A fibrillar-shaped metastable smectic phase forms during orientation-induced crystallization of poly(ethylene terephthalate). We investigated the effects of dimensions and regularity of the smectic phase on the mechanical properties by high-precision X-ray measurements. The drawing stress dependence was 76–168 MPa and the spinning speed dependence of 250–2000 m/min. The proportion, persistence length, and thickness of the smectic phase achieved their maximum values at 0.3–0.4 ms after necking. At this time g II also reached a minimum value of 3.7%–4.3%. The persistence length increased linearly with the natural draw ratio of as-spun fibers at less than 1500 m/min. The maximum values of the proportion, persistence length, and thickness showed no dependence on the drawing stress; however, the proportion and persistence length increased more rapidly. The increase of d-spacing with drawing stress led to an apparent elastic modulus of approximately 40 GPa for the oriented molecular bundle. Graphical abstract Image 1 Highlights • Structure of smectic phase was investigated by high-precision X-ray measurement. • Length of smectic phase increased linearly with the NDR of as-spun fiber. • The Hosemann's disorder parameter of smectic phase was higher than that of crystal. • The d-spacing less than 0.3 ms clearly increased with the drawing stress. • 40 GPa of apparent elastic modulus for the oriented molecular bundle was obtained. [ABSTRACT FROM AUTHOR]

Abstract The surface orientation of crystals has an influence on various material properties, like the oxidation. A method was developed to correlate the oxidation rate for individual single crystal grains with their surface orientation. The surface orientation of many grains of polycrystalline, recrystallized tungsten samples was determined using electron backscatter diffraction. Subsequently, the samples were oxidized in a thermobalance, measuring the time dependent weight increase. The grain dependent oxidation rates were determined by measuring the thickness of the oxide layer for many individual grains with confocal laser scanning microscopy and the scanning electron microscopy on focus ion beam prepared cross-sections. In the temperature range of 720 K to 870 K, tungsten grains with {100} surface orientation have the highest oxidation rate, which is two times higher than the lowest oxidation rate. The lowest oxidation rate belongs to the {111} surfaces orientation, while the {110} surfaces orientation has an intermediated rate. The derived oxidation rates are consistent with gravimetric measurements. They follow an Arrhenius behavior with an activation energy of 190 kJ/mol. Highlights • Method to measure and evaluate orientation of many single crystal grains • Determine the fraction of the oxide layer above and below the original surface level • The oxidation rate vary by a factor of two in temperature range 720 to 870 K [ABSTRACT FROM AUTHOR]

Highlights • First report of using TKD to quantify GND at the nanoscale. • GND density has been measured in HAZ of a super duplex stainless steel sample. • Good agreement is found between TKD & TEM in identifying dislocation distribution. • TKD–GND method is an accurate, fast and accessible method for GND measurement. Abstract It is challenging to quantify the geometrically necessary dislocation (GND) density at the nanoscale using conventional electron backscatter diffraction due to its limited spatial resolution. To overcome this problem, in this study, the transmission Kikuchi diffraction (TKD) technique is used to measure lattice orientation and to calculate the corresponding nanoscale GND density. Using the TKD method, a variation of GND density from 6 × 1014 to 1016 m−2 has been measured in a welded super duplex stainless steel sample. The distribution of dislocation density is shown to be in good agreement with transmission electron microscope (TEM) result. Compared with dislocation measurements obtained by TEM, the TKD–GND method is revealed to be a relatively accurate, fast and accessible method. [ABSTRACT FROM AUTHOR]

Abstract Random close packings (RCP) of different shaped cylindrical particles under optimal vibration conditions were numerically reproduced using discrete element method. Corresponding characteristic macro and micro properties such as packing density, coordination number (CN), radial distribution function (RDF), particle orientation, orientation randomness and forces/stresses as a function of particle aspect ratio (AR) were systematically characterized and analyzed. And the container wall effects on the packing were also comprehensively considered. The results show that with the increase of AR , the packing density of each RCP structure first increases to a maximum (0.70 with AR = 1) and then decreases. The RDF analysis shows the particle arrangement of local structure varies with AR. The container wall is only in effect within three layers for equiaxed cylinders (AR = 1) near the boundary and just one layer for other shaped cylinders. The non-equiaxed cylinders especially elongated ones exhibit a strong tendency to horizontal alignment. With the growth of AR , the nematic order parameter of the packings first decreases to a minimum and then increases. Both particle position and orientation distributions demonstrate that the obtained packing structures are random. Force analyses indicate that the strong forces follow an exponential distribution, while those weak forces follow a power-law distribution, which is comparable to the force distributions of spherical particles. Compared with other cylindrical particles, the force orientation distribution in the packing of equiaxed cylinders is more homogenous. The peak position of the hydrostatic stress distribution is the same for different shaped cylinders. Moreover, with the increase of the packing density, the percentage of strong stresses increases. With the AR deviating from 1, the static vertical stresses present a gradually larger saturation stress in the same depth. Graphical abstract Unlabelled Image Highlights • RCPs of different shaped cylinders under vibrations are reproduced by DEM. • Effects of particle shape and container wall on the packing densification are identified. • Various macro- and microscopic properties of RCP structures are characterized and compared. [ABSTRACT FROM AUTHOR]

Abstract Multiscale graphene/carbon fiber (G/CF) reinforcements were developed for copper matrix hybrid composites. The homegenious G/CF/Cu mixture powders were firstly prepared by the simple wet-mixing process, and then densified by hot-pressed sintering to obtain bulk composites. Microstructure, electrical conductivity and mechanical properties of such composites were investigated. In the sintered compacts, the hybrid G and CF reinforcements distributed randomly in Cu matrix. CF presented the various space orientations, and G nanosheets exhibited the interconnected network distribution. Hardness and tensile yield strength of composites were improved evidently by hybrid G/CF addition, which increased with G increasing. However, the ultimate tensile strength were firstly enhanced and then deteriorated by increasing G content. The lower electrical conductivity showed in the more G-added composite, but still reached more than 80.0% IACS. These performance change could be sought in the spatially geometrical distribution and characteristic of hybrid CF/G additions, and the relevant mechanisms were discussed. [ABSTRACT FROM AUTHOR]

A metal–interlayer–semiconductor (MIS) structure that is realized by inserting an ultrathin interlayer between a contact metal and a semiconductor has been investigated recently as a low-resistance non-alloyed contact structure. However, a comprehensive and systematical investigation of Schottky barrier height (SBH) modulation through the insertion of an interlayer depending on the contact surface orientation has not been conducted despite its importance for its use in multi-gate transistors. Therefore, in this work, the SBH modulation of the MIS contact structure for different contact surface orientations is systematically investigated, and a comprehensive analysis platform of the MIS contact structure is suggested. Two factors, (1) alleviation of Fermi-level pinning due to metal-induced gap states and interface states and (2) formation of the interface dipole, contribute to the SBH modulation in the MIS contact structure. Their contributions depending on the contact surface orientation are evaluated through a comparison of the contact structures on (100)- and (110)-oriented germanium (Ge). These factors and how they should be considered for a certain contact surface in Ge-channel multi-gate transistors are investigated. The investigation and the proposed analysis platform will contribute to the design of high-performance non-alloyed contact schemes for next-generation multi-gate transistors. [ABSTRACT FROM AUTHOR]

This review follows up on Part 1, which focused on classification and evaluation of single drop and sorbent‐based microextraction techniques. Membrane‐ and homogenous phase‐based microextraction techniques are discussed and classified in Part 2. These techniques are more recent than those in Part 1 and considerable attention has been paid to their development. The new methodologies are more sensitive and, thanks to their miniaturization, they can be classified as "green", but no exhaustive classification is available. We hope that this review will contribute to better orientation in these methods. [ABSTRACT FROM AUTHOR]

Highlights • Pt3Al intermetallic alloy supports near-surface discrete breathers (DB). • Properies of DB depend on surface orientation and termination. • DB can localize energy about 1 eV. • DB can help to overcome potential barriers for structure transformations. Abstract It is known that defect-free crystals can support spatially localized, large amplitude vibrational modes with frequencies outside the linear phonon spectrum. Such excitations are called discrete breathers (DB) or intrinsic localized modes. So far, for 3D crystals DB were considered only in the bulk. In the present molecular dynamics study, for the first time, we demonstrate that DB can be excited at the low Miller indices surfaces of the Pt 3 Al intermetallic alloy. It is shown that properties of the DB depend essentially on the surface orientation and termination, as well as on DB polarization. The study of DB at crystal surfaces is important because they can localize energy of order of 1 eV, which can reduce the potential barrier for local structure transformation or a chemical reaction. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A facile strategy to construct silk fibroin (SF) scaffolds with aligned fibers. • High-strength scaffolds crosslinked aligned SF fibers with regenerated SF solution. • Aligned fibers scaffolds developed for guiding neuronal growth direction. • Methylcobalamin loaded scaffold promoted neurite growth and neuron survival. • Methylcobalamin loaded aligned scaffold exhibited good biocompatibility. Abstract Suitable micro/nanofibers orientation in tissue engineered scaffold could guide cells outgrowth and migration during tissue regeneration. However, it is still a challenge to prepare a simple, high-strength and aligned fibers scaffold. Herein, we report a facile strategy to construct high-strength silk fibroin (SF) scaffolds with aligned fibers orientation by crosslinking aligned SF fibers with regenerated SF solution for guiding neuronal growth direction. The fibers could be easily controlled within the same orientation. The aligned fibers and protein-protein interfacial bonding between SF fibers and regenerated SF solution reinforced the mechanical properties to form a high-strength scaffold. Schwann cells and dorsal root ganglion (DRG) neuron could migrate along with the uniform orientation of scaffolds. Mecobalamin was loaded into aligned SF scaffold to promote neurite growth and neuron survival through methylation cycle by activation of Erk1/2 and Akt. Additionally, mecobalamin loaded aligned SF scaffold demonstrated good biocompatibility, inflammatory cells also showed decreased profiles with time extensions. This facile strategy could enrich the fabrication methods to prepare aligned fibers scaffolds in the tissue engineering. [ABSTRACT FROM AUTHOR]