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• Self-tapping screws restored the rotational capacity of connections with cracks. • Partially threaded screws showed a trend to effectively control crack propagation. • A theoretical prediction method is demonstrated. This study uses partially threaded self-tapping screws to enhance the mechanical properties of damaged and undamaged dowel-type timber connections. The damaged connections have a 1.5 mm wide artificial crack across the middle row of the fasteners. Test results showed that screw reinforcement can restore the rotation capacity of damaged connections. The rotational capacity of reinforced connections without cracks is 45.6% higher than unreinforced connections while the improvement on moment-resisting capacity is slight. Digital image correlation (DIC) was used to detect the movement of the connections and validated that the fasteners rotate around the centre of rotation in reinforced connections. Screw reinforcement also demonstrated the ability to control crack propagation, with the reinforced groups showed a reduction of crack length by at least 37% when compared to the unreinforced groups. A calculation method is proposed to calculate the characteristic moment-resisting capacity of damaged and undamaged screw reinforced connections. The calculated values are proven to be conservative when compared with the characteristic value based on the experimental results. [ABSTRACT FROM AUTHOR]

To understand the basic material properties required in selecting a metallic interlayer for enhanced adhesion of diamond coatings on the substrates, the interfaces between diamond and metals with different carbide formation enthalpies (Cu, Ti, and Al) are studied using density functional theory. It is found that the work of separation decreases, while the interface energy increases, with the carbide formation enthalpy ΔHf (TiCu>Al), is needed to achieve a higher overall interface strength. In addition, when the surface energy is larger than the interface energy, a wetted diamond/metal interface is formed during diamond nucleation, providing the strongest adhesion compared to other growth modes. These results indicate that a strong carbide-forming ability and a large surface energy of the interlayer promote nucleation and enhance the adhesion and interface strength of the coating/substrate system. [ABSTRACT FROM AUTHOR]

In this paper, we report a microcrack toughening mechanism for enhancing the adhesion of diamond coating. The oriented microcracks were formed within the TiC interlayer to dissipate strain energy and accommodate deformation via the crack opening-closing mechanism, thus enhancing the coating/substrate interfacial toughness. The delamination of diamond coating was effectively prevented when the parallel microcracks were confined within the interlayer and arrested at interfaces of coating/interlayer/substrate. Density functional theory calculations revealed that the highly anisotropic fracture strength of the TiC phase energetically favors crack initiation and propagation along (100) planes only, which are 54.7° away from the interface. These microcracks are constrained inside the interlayer by the two strong interfaces in the substrate/interlayer/coating system. The new microcrack toughening mechanism with these combined features has a wide application to enhance the adhesion of thin-film coatings. [ABSTRACT FROM AUTHOR]

Highlights • Full-scale testing on timber portal frame with screw reinforcement. • Innovative use of self-tapping screws. • Qualitative discussion on the effectiveness of screw reinforcement. Abstract In this study, partially threaded self-tapping screws have been used as reinforcement on timber portal frames to enhance mechanical performance of dowel-type connections. Experimental tests on unreinforced and reinforced portal frames showed that reinforced frames achieved a 31% and 51% increase in moment-resisting capacity and ultimate rotation, respectively. The test on the reinforced frames was stopped when the stroke on the hydraulic jacks had been reached, while 20% of load drop was not observed. The test results demonstrated the performance of partially threaded self-tapping screws which reduces the drive-in torque when compared to fully threaded self-tapping screws. A theoretical prediction on the characteristic moment-resisting capacity of screw reinforced portal frames is proposed. [ABSTRACT FROM AUTHOR]

Low-index surfaces and morphologies of cobalt spinel (Co 3 O 4 ) are studied using density functional theory calculations. For each of the surfaces (100), (110), and (111), a set of terminations with different surface compositions and atomic structures are assessed to study their thermodynamic stability under different environmental conditions. Surface energies are calculated as functions of oxygen's chemical potential, which in turn is a function of temperature and partial pressure. We select seven typical shapes of cobalt oxide nanoparticles and compute their free energies of formation using the surface energies of all the surrounding facets. The results show that the shapes of octahedron and cuboctahedron have the lowest Gibbs free energies among the seven shapes for all the environmental conditions being explored. [ABSTRACT FROM AUTHOR]

Abstract: Nanoparticulate hematite is a promising material for catalytic and photoelectrochemical applications, where the surfaces are engineered to improve efficiency in different chemical environments. In the presence of water, the surfaces are typically passivated by hydroxyl groups, which modify the surface stability and reactivity. We use density functional theory and first principles thermodynamics to investigate the low-index surfaces (001), (101), and (104) in hydrous environments. For each of the surfaces, we build various hydroxylation configurations and compare their thermodynamic stability under different environmental conditions (temperature, humidity, and supersaturation of oxygen). The results enable us to construct surface phase diagrams, which provide guidance to the selection of surface structures, and the control of environmental conditions for specific applications. [Copyright &y& Elsevier]

Abstract: Three novel terpolymers, i.e. P-1, P-2 and P-3, were prepared from the terpolymerization of butyl p-styrenesulfonate (BSS), methyl methacrylate (MMA) and methacrylic acid (MAA). Thin films composed of the prepared terpolymers, 2,2-bis(4-(2-(vinyloxy)ethoxy)phenyl)propane (BVPP) and an IR dye (in case of laser scanning) were made onto an aluminum substrate. Crosslinking and de-crosslinking reactions would readily take place when the films were treated at 80°C and 220°C for a short period of time, respectively. Along with the chemical structural changes during thermal treatment, great solubility changes could be achieved. It was found that the crosslinked polymer matrix was more resistant to aqueous solution and insoluble in neutral water, whereas the de-crosslinked one such as P-1 matrix could become soluble in neutral water. Based on these properties, a positive-working and neutral water-developable imaging material was proposed and preliminary studies on the imaging property were conducted. [Copyright &y& Elsevier]

Carbon fiber reinforced polymer (CFRP) composites with self‐sensing and self‐healing capabilities was developed in this work. Uniform dispersion of CNTs within a core‐shell nanofiber structure was achieved through a combination of electrospinning and subsequent surface spraying of CNTs. The resulting core‐shell nanofibers were incorporated into CFRP composites using a vacuum‐assisted resin transfer molding process. Mechanical testing demonstrated improved mechanical properties in the composites treated with CNT spraying. Real‐time, precise monitoring of structural damage was enabled through the measurement of electrical signal changes caused by composite deformation in static loading experiments. Furthermore, self‐healing experiments demonstrated that the thermally conductive network formed by CNTs facilitated more uniform heat transfer within the composites. During the healing process, resistive heating of damaged specimens was applied, resulting in a remarkable healing efficiency of 95.2%. The experiments indicate that the composite developed in this paper possess excellent self‐sensing and self‐healing capabilities. Highlights: Damage self‐sensing and self‐healing CFRP composites were developed.CNTs‐modified nanofibers were applied to endow the composite specific abilities.Resistivity signals were collected for real‐time damage monitoring.The self‐healing efficiency of the designed composite reached up to 95.2%.Self‐sensing and self‐healing occurred autonomously within closed‐loop structure. [ABSTRACT FROM AUTHOR]

In this paper, an enhanced VARTM process is proposed and its pressure effect on resin infusion behavior and composite material performance is studied to reveal the control mechanism of the fiber volume fraction and void content. The molding is vacuumized during the resin injection stage while it is pressurized during the mold filling and curing stages via a VARTM pressure control system designed in this paper. Theoretical calculations and simulation methods are used to reveal the resin's in-plane, transverse, and three-dimensional flow patterns in multi-layer media. For typical thin-walled components, the infiltration behavior of resin in isotropic porous media is studied, elucidating the control mechanisms of fiber volume fraction and void content. The experiments demonstrate that the enhanced VARTM process significantly improves mold filling efficiency and composite's performance. Compared to the regular VARTM process, the panel thickness is reduced by 4% from 1.7 mm, the average tensile strength is increased by 7.3% to 760 MPa, the average flexural strength remains at approximately 720 MPa, porosity is decreased from 1.5% to below 1%, and the fiber volume fraction is increased from 55% to 62%. [ABSTRACT FROM AUTHOR]

As the climate changed in recent years, an increase in summer indoor temperatures in severe cold and cold regions of China has started to affect thermal comfort. However, the local design standard for energy efficiency does not recognize this phenomenon. This paper reports the potential overheating phenomenon in residential buildings and examines the rationale for the current thermal designs adopted in severe cold and cold regions of China. In this study, the two most commonly used building materials, reinforced concrete (RC) and cross laminated timber (CLT), are used separately in the design of an 18-story residential building envelope located in six different cities in the severe cold and cold regions. The energy consumption and indoor operative temperatures during the operation of these buildings are simulated using Integrated Environmental Solutions Virtual Environment (IES VE). The results demonstrate that both the RC and the CLT buildings experience varying degrees of overheating in any climate subregion. The CLT buildings have longer overheating hours compared to the RC buildings, especially in the cold regions. The results also indicate that for apartments on higher stories, the cooling energy consumption and indoor temperature also increase gradually. The research results suggest that the local design standard for energy efficiency needs to be adjusted by adding thermal design methods for summer to reduce the periods of overheating. [ABSTRACT FROM AUTHOR]

Hydrogen atmosphere can significantly change the tribological behavior at diamond and diamondlike carbon (DLC) surfaces and the friction-reducing effect depends on the partial pressure of hydrogen. We combined density functional theory modeling and thermodynamic quantities to predict the equilibrium partial pressures of hydrogen at temperature T, PH2 (T), for a fully atomic hydrogen passivated diamond surface. Above the equilibrium PH2 (T), ultralow friction can be achieved at diamond and DLC surfaces. The calculation agrees well with friction tests at various testing conditions. We also show that PH2 (T) increases with temperature; therefore, the temperature effect observed in friction tests should first be treated as an equilibrium factor rather than a kinetic factor. [ABSTRACT FROM AUTHOR]

As the impact of climate change intensifies, meeting the energy demand of buildings in China's cold regions is becoming increasingly challenging, particularly in terms of cooling energy consumption. The effectiveness of integrating phase change material (PCM) into building envelopes for energy saving in China's cold regions is unclear. The aim of this study is to assess the effectiveness of PCM integration in building enclosures for energy efficiency in these regions. The research monitored and recorded indoor temperature data from typical residential cases from May to September. This measured data was then used to validate the accuracy of EnergyPlus22-1 software simulation models. Subsequently, the calibrated model was utilized to conduct a comparative analysis on the effects of PCM on indoor temperatures and cooling energy consumption across these regions. The results of these comparative analyses indicated that PCM can alleviate indoor overheating to varying degrees in severe cold regions of China. Focusing on north-facing bedrooms, applying PCMs reduced the duration of overheating in non-air-conditioned buildings in severe cold regions of China by 136 h (Yichun), 340 h (Harbin), 356 h (Shenyang), and 153 h (Dalian). In terms of cooling energy consumption, the energy saved by applying PCMs ranged from 1.48 to 13.83 kWh/m2. These results emphasize that the performance of PCM varies with climate change, with the most significant energy-saving effects observed in severe cold regions. In north-facing bedrooms in Harbin, the energy-saving rate was as high as 60.30%. Based on these results, the study offers guidance and recommendations for feasible passive energy-saving strategies for buildings in severe cold and cold regions of China in the face of climate change. Additionally, it provides practical guidance for applying PCMs in different climatic zones in China. [ABSTRACT FROM AUTHOR]

Various metal ions, including Mg, Co, Nb, and W, were chfosen for ion implantation to modify TiO 2 nanowire arrays. The introduction of metal ions was confirmed by both simulations and transmission electron microscopy (TEM) morphology characterization. A doped TiO 2 shell on the surface was formed by the ion implantation process. Furthermore, the unbonded metal W was found in the doped TiO 2 nanowires. The XPS results implied a special mechanism of heavy ions chosen for low-energy ion implantation. The presence of non-bonded metal restricted water splitting ability evidently. PEC results provided brief evidence that Nb doped TiO 2 nanowire arrays is a promising choice with a 60% improvement in current density. The charge transfer resistance and the flat band potential are more benefit to water splitting than other doped metal ions. The theoretical calculation also supported efficient band gap narrowing of TiO 2 caused by Nb dopant. [ABSTRACT FROM AUTHOR]

Self‐healing composites are promising for engineering, but self‐healing structures or components usually induce reduction in the composite's mechanical properties. In this paper, core‐shell nanofibers which accommodating healing agent in the core and incorporating carbon nanotubes (CNTs) in the shell were produced to develop non‐destructive self‐healing carbon fiber/epoxy (CF/EP) composites. The epoxy resin and curing agent were encapsulated in CNTs‐reinforced polyacrylonitrile (PAN) core‐shell electrospinning nanofiber mats and the mats were placed on carbon fibers to fabricate CF/EP composite laminates by the vacuum‐assisted resin transfer molding (VARTM) process. The results indicated that the flexural strength, flexural modulus, tensile strength, tensile modulus, and Mode II interlaminar fracture toughness of composites with suitable self‐healing components increased by 49%, 44%, 8%, 13%, and 43%, respectively, compared to the pristine CF/EP. The healing flexural strength of the composite with 1 wt% CNTs recovered up to 93.57%, observed 24 h after the bending fracture, which is higher than the initial strength of CF/EP composites without self‐healing components. The research indicates that self‐healing composites can be developed without mechanical properties degrade and even achieve stronger mechanical properties. [ABSTRACT FROM AUTHOR]

Highlights • Inverse Wulff construction is used to backtrack surface energies from experimentally observed particle shapes. • The method can obtain exact surface-energy ratios of coexisting surfaces, and lower bounds for missing surfaces. • A general four-parameter function is proposed to simplify calculations of surface-energy ratios. • The method is applicable to non-centrosymmetric crystal particles for which symmetry centers are undefined. Abstract Morphologies of nanoparticles are an important factor that defines various nanomaterials' properties and applications. Wulff construction is an effective tool to understand and predict the morphologies of nanoparticles. Lack of surface energies, however, poses obstacles to applicability of this method. We use inverse Wulff construction, based on nonlinear optimization and crystal symmetries, to acquire surface energies from Wulff shapes. This method is capable of calculating not only the surface energies of those coexisting surfaces of a particle, but also lower bounds of surface energies of missing surfaces. We use the m 3 ¯ m crystal class to verify numerical surface energies by optimization against analytical results by thermodynamic equilibrium between coexisting surfaces. We further propose a general function for the surface-energy ratios. The method can be used to study evolution of surface energies from particles' shapes for thermodynamic modeling that takes surface energies as input parameters. [ABSTRACT FROM AUTHOR]

In China, the post-Winter Olympics era has seen the rapid development and promotion of ice rinks with air-supported membrane structures. With the rise of large indoor spectator areas in ice rinks, thermal comfort needs in spectator areas are receiving more and more attention. The satisfaction of thermal comfort needs is crucial to people's health and well-being, so further study of the issue of thermal comfort in such spectator areas is needed. Unfortunately, models currently used to evaluate the thermal comfort of traditional building envelopes are not applicable to air-supported membrane-envelope ice rinks. Researchers need to focus on the internal thermal comfort needs of air-supported membrane envelopes for spectator areas. The aim of this research was to establish a thermal comfort model to provide exact temperature-range recommendations for spectator areas in air-supported membrane ice rinks. The indoor thermal-environment parameters of the ice rink in Harbin were measured from 2 January to 15 January 2023. To elicit data on spectators' actual thermal sensations in the ice rink, a field questionnaire was administered. By modifying the expectancy factor, an extended predicted thermal comfort model was established. The results suggested that the operative temperature required to meet spectators' thermal comfort needs in the case study ice rink ranged from 17 °C to 26 °C. The results of the study offer specific insights into the indoor thermal comfort needs of air-supported ice rinks and provide a more accurate temperature-setting reference for the healthy and energy-efficient development of such rinks. [ABSTRACT FROM AUTHOR]

Boehmite (010) surface has a high density of ordered hydroxyl groups but no intrinsic hydrogen bonds. This represents a special case for which proton‐transfer mechanism is unknown and different from those along a continuous hydrogen‐bond network. In this study, probable pathways for proton transfer on boehmite (010) surface in both anhydrous and hydrous environments are explored, and energy barriers of these processes are calculated using the climbing‐image nudged elastic band method based on density‐functional theory. The results reveal that under anhydrous conditions, long‐distance proton transfer is unlikely on clean (010) surface, but excess protons are mobile with a low proton‐transfer energy barrier of 31.4 kJ mol−1. Subsurface Zn dopants (for charge balance with excess protons) reduce the energy barrier to 21.1 kJ mol−1. In contrast, water‐mediated proton‐transfer processes only need to overcome a low‐energy barrier of 10.0 kJ mol−1. The low‐energy barriers suggest boehmite (010) surface can conduct protons, particularly in hydrous environments, making boehmite a promising filler material for proton exchange membranes. [ABSTRACT FROM AUTHOR]

The present study was clarified the relationship between NG2 glial cells and 5-hydroxytryptamine (5-HT) to further revealed a role in the regulation of cortical excitability. The co-localization of NG2 cells and 5-HT in rat prefrontal cortex was determined using immunofluorescence. Different concentrations of 5-HT were applied to cultured NG2 cells. Real-time PCR measured the expression of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and brain-derived neurotrophic factor (BDNF). Changes in the expression of IL-1β, TNF-α, and BDNF in NG2 cells were detected after the addition of 5-HT receptor specific blockers and phospholipase C (PLC) specific activators and inhibitors. The results confirmed that the NG2 protein and 5-HT co-localized in the prefrontal cortex. 5-HT treatment of NG2 cells significantly reduced the expression of IL-1β and BDNF mRNA and increased the expression of TNF-α. The 5-HT receptor specific inhibitors alverine citrate, ketanserin, ondansetron and SB-399885 blocked the regulatory effects of 5-HT on NG2 cells. The PLC signal was linked to the secretion of IL-1β, TNF-α and BDNF in NG2 cells. These results indicated that 5-HT affected IL-1β, TNF-α, and BDNF secretion from NG2 cells via the 5-HT1A, 5-HT2A, 5-HT3, 5-HT6 receptors and the PLC signaling pathway. [ABSTRACT FROM AUTHOR]

The corrosion resistance of multi-principal element alloy (MPEA) films is complex dependent on their composition. The purpose of this paper is to explain the relationship between the corrosion resistance and the Cu content of AlCuxNiTiZr MPEA films. AlCuxNiTiZr films were deposited by magnetron sputtering. Their corrosion resistance in 3.5 wt. % NaCl was studied by potentiodynamic polarization experiment and inductively coupled plasma emission spectroscopy. In this paper, the potentiodynamic polarization curve is analyzed from the perspective of corrosion type and corrosion control. Combined with x-ray photoelectron spectroscopy, the change in corrosion current density in AlCuxNiTiZr films is explained. [ABSTRACT FROM AUTHOR]

Niobium‑chromium (Nb Cr) carbide coatings were deposited on graphite using the thermo-reactive deposition and diffusion (TRD) technique. The microstructure, hardness, and coefficient of thermal expansion were characterized to search for the optimal treatment parameters for hard and adherent coatings on graphite. The growth rate increased with treatment temperature for fixed treatment duration and remained constant at a constant temperature for about 6 h. The coatings were found to consist of alternating Nb and Cr layers, and this interesting multilayer structure might be explained by the thermodynamics of oxide reduction and carbide formation reactions. Compared to the single-carbides layer, the hardness of the complex coatings increased from about 2500 HV to above 3000 HV, and displayed a smaller gradient of the depth-dependent hardness from the coating to the substrate. The variation of coefficient of thermal expansion of the samples with temperature was similar to that of the graphite substrate at temperatures from 40 to 450 °C. These results showed the effectiveness of the TRD method for synthesizing hard and adherent carbide coatings on graphite, and for other coating/substrate systems with sharply dissimilar mechanical properties. [Display omitted] • Nb Cr complex carbide layers were formed on graphite materials by the TRD technique for the first time. • The maximum coating thicknesses can reach up to 20 μm, positively correlate with the TRD treatment temperature/time. • The elements distributions and unique alternating Nb Cr multilayer structure in the coatings were reported and discussed. • The coatings showed excellent hardness performance (>2500 HV) with good adhesions to the graphite substrates. [ABSTRACT FROM AUTHOR]

In deposition of nitride films through reactive sputtering, the degree of nitrogen dissociation from N 2 in vacuum chambers is small and difficult to control, while the nitrogen sputtered from a nitride target is in the ionic state, reactive, and tunable through the power of the target. In this study, co-sputtering of TaN target and Ta target is used to prepare tantalum nitride films of Ta 2 N phase with low resistance and low temperature coefficient of resistance (TCR). We investigated effects of the power of the TaN target and annealing temperature on the phase, structure, and electrical properties of the thin films, and obtained an optimal Ta 2 N-phase thin-film with adjustable resistance in the low segment and a TCR of −8 ppm/°C. • The metal Ta atoms from the Ta target easily take over the ion state N component from the TaN target. • Tantalum nitride films with low resistance and low TCR were successfully prepared by co-sputtering Ta and TaN targets. • Vacuum annealing at a medium temperature improves the electrical properties of the film. • The best tantalum nitride film has a square resistance of 2.586 Ω·□−1, a resistivity of 243.084 μΩ·cm, and a TCR of −8 ppm/°C. [ABSTRACT FROM AUTHOR]

The powder immersion reaction assisted coating (PIRAC) method was used to fabricate a coating on the graphite surface. The graphite was immersed into Cr powder and annealed at 1173–1373 K. The iodine powder was admixed with the Cr powder to investigate the contribution of iodine to the growth and mechanical properties of the coating. After 4 h of PIRAC treatment with or without iodine, Cr7C3- and Cr23C6-based coatings were formed, respectively. The iodinated samples had a higher hardness and thickness, and the friction coefficient was slightly higher than that of the iodine-free sample. The mechanisms for the formation of PIRAC-chromium carbide coatings are explained, and the variations in the produced coatings are discussed. [ABSTRACT FROM AUTHOR]

Abstract: The elastic and thermodynamic properties of NiB, Ni2B, Ni3B, orthorhombic Ni4B3(O–Ni4B3), monoclinic Ni4B3(M–Ni4B3), and Ni23B6, are calculated via first-principles method for the Ni–B system. The ground state energies, the full sets of elastic constants and the associated macroscopic elastic parameters of these Ni–B alloys are computed for the first time. Taking contributions from lattice vibrations and thermally excited electrons into account, thermodynamic properties at finite temperatures are then predicted. In addition, we measure the molar heat capacity at constant pressure for NiB and compare the results with the theoretical predictions. Various calculations demonstrate that the first-principles calculation can be used to clarify the diverse experimental data, and provide reliable thermodynamic data. [Copyright &y& Elsevier]

Eu-doped rare earth sesquioxides RE2O3:Eu (RE = Lu, Y, Sc) exhibit subtle difference in scintillation processes, for which impurity levels play an important role but are difficult to assess computationally due to localized f-electrons and itinerant spd-electrons in the materials. Unpaired electrons of dopant Eu3+ ions also render complexity to these systems. In this study we calculated band structures of pure and Eu-doped RE2O3 using quasi-particle GW approximation with collinear spin polarization based on density functional theory. The band structures were similar across the three host material systems, varying with spin component and dopant's lattice site. Only the majority-spin states are responsible for the scintillation process, whereas the minority-spin states are entangled with the hosts' low-energy conduction bands. The materials' afterglow behavior was explained in terms of the positions of 4f orbitals and electron traps, as well as thermodynamics of the doping systems. [ABSTRACT FROM AUTHOR]

• AlCuNiTiZr high entropy alloy films deposited by magnetron sputtering • AlCuNiTiZr films showing excellent anti-corrosion properties • A scheme of a reasonable equivalent electrical circuit proposed In this study, corrosion-resistant AlCuNiTiZr high-entropy alloy (HEA) films were deposited by direct current magnetron sputtering. The films were found to be amorphous. Corrosion resistance of the films in 0.5 M H 2 SO 4 solution were investigated and compared with 316L stainless steel. The minimum corrosion current density of the HEA films was about one order of magnitude lower than that of 316L stainless steel. The inductively coupled plasma optical emission spectra showed that the concentrations of Cu, Ni, Ti and Zr ions in the corrosion solution were as low as 10−7 mol / L, while the concentration of Al ions was 7.5×10−6 mol / L. It is revealed that two passivation layers were formed on the surface from electrochemical impedance spectroscopy and equivalent electrical circuit, and the passivation layers resulted in protective effect on the AlCuNiTiZr HEA films in the sulfuric acid solution. [ABSTRACT FROM AUTHOR]

C21H25ClO, orthorhombic, Pna21 (no. 33), a = 14.152(2) Å, b = 22.112(3) Å, c = 6.0109(7) Å, V = 1880.9(4) Å3, Z = 4, Rgt(F) = 0.0586, wRref(F2) = 0.1227, T = 150 K. [ABSTRACT FROM AUTHOR]

C21H25ClO, orthorhombic, Pna21 (no. 33), a = 14.152(2) Å, b = 22.112(3) Å, c = 6.0109(7) Å, V = 1880.9(4) Å3, Z = 4, Rgt(F) = 0.0586, wRref(F2) = 0.1227, T = 150 K. [ABSTRACT FROM AUTHOR]

Biomass carbon-based MnO electrode materials were synthesized using ramie as the biomass precursor of carbon and potassium permanganate as the precursor of MnO. The ramie-activated carbon/manganese monoxide (RAC/MnO) composite electrodes exhibited a specific capacitance of 720 F/g at a current density of 0.5 A/g. A symmetric cell assembled using the composite electrodes showed a specific capacitance of 45 F/g at 0.5 A/g and an energy density of 12.25 Wh/kg at a power density of 350 W/kg. The excellent electrochemical performance was analyzed by characterizing the electrodes' chemical composition, microstructure, crystal orientation, specific surface area, and pore distribution. Because of the large overpotential of MnO, the composite electrode's working voltage reached 1.4 V, which is 40% higher than 1.0 V of traditional carbon electrodes. As such, supercapacitors can have higher energy density and power density with the RAC/MnO composite electrodes. The experimental equipment for synthesizing the electrodes is very simple and is promising for large-scale commercialization. [ABSTRACT FROM AUTHOR]

Solidly mounted resonators (SMRs) rely on high-quality Bragg reflectors, for which tungsten has been used as the high acoustic impedance layer. It is unclear about the effects of tungsten phases on the acoustic performance of SMRs. In this study, high-quality flat layers of different phase structures of W (α-W and β-W) are obtained by changing the post-growth annealing temperature and magnetron sputtering parameters. Our results show that the α-W has higher Young's modulus and acoustic impedance (205 GPa and 63 kg/m2s) than β-W (170 GPa and 57 kg/m2s). These small differences result in amplified difference in acoustic performance of Bragg reflectors using tungsten (W) as their high-impedance layer. Our tests show that the SMR of α-W Bragg reflector has a higher return loss (18.4 dB) at around 2.75 GHz and higher quality factor (687) than that of β-W Bragg reflector (9.2 dB and 228, respectively). • Different phase structures of W are obtained by changing the annealing temperature and magnetron sputtering parameters. • The acoustic impedance of α-W is 10% higher than that of β-W. • The influence of α- and β-W phases on performance of SMR devices is different. [ABSTRACT FROM AUTHOR]

Short term load forecasting (STLF) is one of the basic techniques for economic operation of the power grid. Electrical load consumption can be affected by both internal and external factors so that it is hard to forecast accurately due to the random influencing factors such as weather. Besides complicated and numerous internal patterns, electrical load shows obvious yearly, seasonal, and weekly quasi-periodicity. Traditional regression-based models and shallow neural network models cannot accurately learn the complicated inner patterns of the electrical load. Long short-term memory (LSTM) model features a strong learning capacity to capture the time dependence of the time series and presents the state-of-the-art performance. However, as the time span increases, LSTM becomes much harder to train because it cannot completely avoid the vanishing gradient problem in recurrent neural networks. Then, LSTM models cannot capture the dependence over large time span which is of potency to enhance STLF. Moreover, electrical loads feature data imbalance where some load patterns in high/low temperature zones are more complicated but occur much less often than those in mild temperature zones, which severely degrades the LSTM-based STLF algorithms. To fully exploit the information beneath the high correlation of load segments over large time spans and combat the data imbalance, a deep ensemble learning model within active learning framework is proposed, which consists of a selector and a predictor. The selector actively selects several key load segments with the most similar pattern as the current one to train the predictor, and the predictor is an ensemble learning-based deep learning machine integrating LSTM and multi-layer preceptor (MLP). The LSTM is capable of capturing the short-term dependence of the electrical load, and the MLP integrates both the key history load segments and the outcome of LSTM for better forecasting. The proposed model was evaluated over an open dataset, and the results verify its advantage over the existing STLF models. [ABSTRACT FROM AUTHOR]

Graphite may store lithium or potassium, but not sodium, in its interlayer space under ambient conditions. It is, however, unclear whether binary alkali alloys of Li-Na, Li-K, and Na-K may substitute pure Li or K to form binary alkali alloy-graphite intercalation compounds. We investigate thermodynamics of the binary alloy-graphite intercalation compounds using density functional theory with van der Waals density functionals. We find Li-rich co-intercalation compounds and K-rich ones are associated with negative formation energies, and the Na-K alloy has the broadest domain of co-intercalation (approximately up to 36% Na). Because of convexity of the formation-energy functions, these compounds are metastable and tend to decompose even when formation energies are negative. Na metal is among the decomposition products. Binary Li-K alloys in graphite form segregated phases of LiC6 and KC8, and this allows one to fabricate Li-K mixed-ion batteries using graphite anodes, whereas Li-Na and Na-K alloys are thermodynamically unfavorable. The study highlights the importance of convexity of formation-energy functions in thermodynamics of alloy-graphite intercalation compounds. [ABSTRACT FROM AUTHOR]

Highlights • The new five local states are introduced in the a-SiO x (Mo) layer. • The charge transition levels are located at 2.54, 3.59, 5.82 and 7.05 eV separately. • The Mo-related defect-assisted tunneling is presented in MoO x /n-Si PV devices. Abstract An amorphous silica layer containing Mo component (a-SiO x (Mo) ∼ 3.5–4.0 nm) is naturally formed in the process of evaporating MoO 3 power onto n-type silicon, which plays a significant role on the non-equilibrium carriers' transport of MoO x /n-Si heterojunction photovoltaic device. The electronic structure and the charge transition levels of the amorphous silicon oxide doped with Mo are derived from density functional theory. The density of states show that the five local states are existed in the band gap of amorphous silicon oxide, caused by the hybridization of Mo 4d orbital and O 2p orbital. The charge transition level of ε(+1/0) is located at 3.59 eV above the valance band maximum of a-SiO 2 , which could be a passageway of holes produced in the opto-electric conversion. Defects level-assisted quantum transport mechanism is put forwarded to explain hole transport phenomenon in the MoO x /SiO x (Mo)/n-Si PV device. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we report a nanostructured CMK-3/NiCo 2 S 4 electrode material for supercapacitors. Owing to the introduction of CMK-3, the CMK-3/NiCo 2 S 4 electrode exhibits a novel nanostructure of nanorods, and has a great improvement in conductivity. The CMK-3/NiCo 2 S 4 electrode demonstrates a high specific capacitance (1843.1 F g−1 at 1 A g−1, 3.89 F cm−2 at 2 mA cm−2) and excellent cycling stability (94.2% over 2000 cycles at 10 A g−1). Moreover, an asymmetric supercapacitor (ASC) device is assembled with CMK-3/NiCo 2 S 4 and activated carbon (AC) as positive and negative electrode, respectively, to characterize the electrodes' electrochemical performance. The ASC device achieves a high energy density (34.9 Wh/kg at 357 W/kg) and a high power density (7300 W/kg at 15.3 Wh/kg), suggesting that the composite is a superior electrode material for high-performance supercapacitors. Graphical abstract Image 1 Highlights • CMK-3/NiCo 2 S 4 nanostructured films have been successfully grown by facile methods. • Ultrahigh specific capacitance with superior rate performance has been achieved. • An asymmetric supercapacitor with high energy density was successfully assembled. [ABSTRACT FROM AUTHOR]

Activated biomass carbons (ABC) produced from bamboo by carbonization and activation have high specific surface areas and mesoporous structures. The specific surface area, total pore volume, and average pore size of the activated biomass carbon are controlled by adjusting the activation temperature from 700 to 1000 °C. The carbon materials activated at 900 °C have an optimal mesoporous structure with a high specific surface area (2221.1 m 2  g −1 ), the highest capacitance (293 F g −1 at 0.5 A g −1 in 3 M KOH aqueous electrolyte) and excellent rate capability (193.8 F g −1 at 20 A g −1 ). Symmetric supercapacitors made of the optimal electrodes exhibit a high energy density of 10.9 Wh kg −1 (18.2 Wh L −1 ) at a power density of 63 W kg −1 (105 W L −1 ) and outstanding capacitance retention of 91.8% over 10,000 cycles. The high electrochemical performance of the mesoporous ABCs show that they are highly promising for energy-storage applications with further optimization. [ABSTRACT FROM AUTHOR]

Chromium‑niobium (Cr Nb) carbide coatings were formed on graphite by powder immersion reaction assisted coating (PIRAC) method. In our experiments, a small amount of iodine was added to the mixture of Cr and Nb powder to lower the annealing temperature to as low as 1173 K. The resultant composite coatings comprised Cr 7 C 3 and NbC phases, of which the Cr 7 C 3 phase was found in the graphite's internal gaps and NbC was distributed on the surface of the coatings. The formation of the multilayer structure might be explained by thermodynamics of metal iodides and carbides. The optimal composite coating's hardness was close to that of Cr C compounds coatings, and its toughness was close to that of NbC coatings. Thermal expansion coefficient of the coated sample was similar to the graphite matrix within the temperature range of 313-673 K. No cracks were observed even though stress mismatch was expected due to the large temperature change and large difference in mechanical properties between carbides and graphite. These results showed that the multilayer structure of Cr Nb composite coating synthesized by PIRAC was promising for improving the mechanical properties of the graphite. • Graphite has been widely used for making various devices. Its soft and fragile nature is, however, a shortcoming that shortens service life of graphite-based components. • We test the viability of an inexpensive approach, namely powder immersion reaction assisted coating (PIRAC) method. • We prepared composite Cr-Nb carbide coatings on graphite using the PIRAC method with the aid of iodine, and investigated the effect of processing conditions on the material microstructure and mechanical properties. • We observed a layering structure in which the Cr C compound in the lower layer and NbC in the upper layer. • The optimal composite coating has high hardness close to that of chromium carbides, and high elastic modulus and toughness close to that of niobium carbide. [ABSTRACT FROM AUTHOR]

Ordered mesoporous carbon (CMK-3) was fabricated by a simple nanocasting method using SBA-15 as a hard template. The CMK-3 had a two-dimensional hexagonal mesoporous structure and a specific surface area of approximately 975.9 m g. The CMK-3 was modified by HNO solutions with magnetic stirring and ultrasonic activation, respectively, to explore the influence of various activation methods on pore structure, surface state, morphology, and electrochemical performance. The CMK-3 modified by ultrasonic activation (CMK-3-US) reached the optimal specific capacitance of 233.4 A g at 0.5 A g and retained 94.2% after 500 cycles in 3 M KOH electrolyte. Furthermore, a symmetric supercapacitor was successfully assembled using CMK-3-US electrodes, which delivered an excellent energy density of 21.5 Wh kg at a power density of 225 W kg and exhibited great long-term stability with 97.5% retention after 4000 cycles. Compared to magnetic stirring activation, ultrasonic cavitation could better increase the efficiency of the HNO activation for mesoporous carbon particles. The results indicate ultrasonic activation is an efficient way to modify carbon-based electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]

In this work, Mg 4 Ta 2 O 9 single crystal was synthesized by optical floating zone method in N 2 atmosphere. The luminescence behavior of Mg 4 Ta 2 O 9 single crystal was investigated through experimental and first-principles calculation methods. Its photoluminescence, scintillation and thermal stimulated luminescence properties, including photoluminescence excitation, photoluminescence, photoluminescence decay, thermal stimulated luminescence and X-ray excited luminescence spectra, were measured. In addition, the temperature dependence of photoluminescence, photoluminescence decay and photoluminescence afterglow curves of Mg 4 Ta 2 O 9 were measured and discussed. Combined with the experimental and density functional theory calculations result, the energy transfer schematic diagrams of the Mg 4 Ta 2 O 9 were proposed to explain the photoluminescence, scintillation, and thermal stimulated luminescence behaviors. • Mg 4 Ta 2 O 9 single crystal was grown by floating zone method in N 2 atmosphere. • PL, scintillation and TSL were measured and discussed systematically. • The TSL spectra of MTO is firstly reported. • Try to explain luminescence behavior by DFT calculation results. [ABSTRACT FROM AUTHOR]

Lu 2 O 3 :Eu, Lu 2 O 3 :Eu,Hf and Lu 2 O 3 :Eu,Zr transparent ceramics (TC) were fabricated using vacuum sintering followed by heat isostatic pressure (HIP). The structure of the samples was measured by X-ray diffraction (XRD). The X-ray induced coloration and bleaching behavior of Lu 2 O 3 :Eu TC is reported for the first time. The transmission and X-ray excited luminescence (XEL) spectra before and after irradiation and after bleaching were measured. By adopting the energy level diagram of Lu 2 O 3 :Eu calculated by first-principles calculation, coloration and bleaching mechanisms of Lu 2 O 3 :Eu TC were proposed. In addition, the impact of hafnia and zirconia on the optical, photoluminescence and scintillation properties of Lu 2 O 3 :Eu TC was discussed and analyzed through the morphology, photoluminescence and scintillation properties, including transmission curves, scanning electron microscope (SEM), photoluminescence excitation (PLE), photoluminescence (PL), PL decay curves, XEL curves and afterglow curves. • Highly transparent Lu 2 O 3 :Eu ceramics are synthesized by vacuum sintering followed HIP sintering. • Through first principle calculation, the mechanism of X-ray induced coloration and 450 nm light bleaching in Lu 2 O 3 :Eu were presented. • ZrO 2 and HfO 2 can drastically improve the optical quality and decrease the afterglow level of Lu 2 O 3 :Eu. [ABSTRACT FROM AUTHOR]

Zirconium aluminum nitride thin films (Zr 0.11 Al 0.89 N) were prepared on different substrates using unbalanced DC reactive magnetron co-sputtering. The influence of sputtering atmosphere, including N 2 /Ar-flow ratio and their total pressure, on the crystalline structure and the electrical properties of the Zr 0.11 Al 0.89 N films has been investigated. In this work, the optimal N 2 /Ar-flow ratio is 1:1 and the optimal total pressure is 0.5 Pa. The resultant Zr 0.11 Al 0.89 N films have a wurtzite structure that is preferentially oriented along the c-axis and have uniform grains. The dielectric constant, dielectric loss, leakage current density and resistivity of the Zr 0.11 Al 0.89 N films reach ~ 16, ~ 0.01 (in a frequency range of 10 3 –10 6 Hz), 3.0 × 10 − 8 A/cm 2 and 1.92 × 10 12 Ω·cm, respectively, which are all superior to those under suboptimal conditions. Moreover, the Zr 0.11 Al 0.89 N films exhibit higher dielectric constants, as well as much lower dielectric loss and leakage current density compared to that of pure AlN films. [ABSTRACT FROM AUTHOR]

NiCoS-based nanostructured films have been grown directly onto nickel foams by a facile two-step method, involving the growth of NiCo-precursor and subsequent conversion into NiCoS via a sulfidation process, with the aid of sodium dodecyl surfactant (SDS). This synthesis method enables the fabrication of binder- and conductive additive-free electrodes for supercapacitors. The influence of the surfactant on the crystal structure, morphology, and electrochemical performance of the electrodes has been investigated. The NiCoS-SDS films exhibit a complex cellular and hierarchical porous structure, which are different from NiCoS-pure films with nanotube arrays structure. Moreover, the electrochemical tests show that the NiCoS-SDS nanostructured electrode exhibits an ultrahigh specific capacitance of 2519 F g at 0.5 A g, which doubles that of the NiCoS-pure nanotube arrays electrode. In addition, the NiCoS-SDS electrode exhibits excellent cycling stability with 90.7 % capacitance retention at 10 A g after 8000 cycles. In view of the low cost and superior electrochemical performance, the NiCoS-SDS electrodes are promising electrode materials for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Devices based on AlN generally require adherent and strong interfaces between AlN and other materials, whereas most metals are known to be nonwetting to AlN and form relatively weak interfaces with AlN. In this study, we selected four representative metals (Al, Cu, Ti, and Zr) to study the adhesion strength of the AlN/metal interfaces. Mathematical models were constructed between the adhesion strength and enthalpy of formation of Al–metal solid solutions, the surface energies of the metals, and the lattice mismatch between the metals and AlN, based on thermodynamic parameters calculated using density functional theory. It appears that the adhesion strength is mainly determined by the lattice mismatch, and is in no linear correlation with either the Al–metal solution's formation enthalpies or the metals’ surface energies. We also investigated the nucleation thermodynamics of the four metals on AlN substrates. It was found that Ti forms the strongest interface with AlN, and has the largest driving force for nucleation on AlN substrates among the four metals. [ABSTRACT FROM AUTHOR]

Highly c-axis oriented aluminum nitride films have been successfully grown by DC magnetron reactive sputtering with unbalanced magnetic fields at room temperature. It is shown that the application of unbalanced magnetic fields can improve the extent of preferential growth along the c-axis, and form AlN films with denser, larger grains and smaller surface roughness, compared to that grown with balanced magnetic fields. The AlN films prepared under optimized growth conditions have a dielectric constant of approximately 10.5 and a dielectric loss of 0.02 in the frequency range of 10 3 –10 6 Hz, and a leakage current of <1 × 10 −7 A/cm 2 at 5 V bias voltage, all the dielectric and insulating properties being superior to the films synthesized with balanced magnetic fields. In this work, the unbalanced magnetic fields are induced by adding an electromagnetic coil on the magnetron cathode. [ABSTRACT FROM AUTHOR]

Nanostructured MnO 2 films have been deposited on nickel foams by a hydrothermal synthesis route under a low magnetic field. It was shown that even though the magnetic field was weak (at a level of several millitesla), it induced substantial change in the nanostructures and electrochemical properties of the MnO 2 films. The as-prepared MnO 2 thin films were largely amorphous and had a spherical superstructure composed of thin nanoflakes. The size of the microspheres decreased and, accordingly, the specific surface area increased with increasing magnetic field’s strength. A probable formation mechanism for the nanostructures of MnO 2 was proposed that the weak magnetic field enhanced the nucleation rate, and modified subsequent growth and aggregation processes, which all had a significant influence on the morphology and electrochemical performance of the MnO 2 electrodes. The optimal MnO 2 electrode synthesized under the low magnetic fields had a specific capacitance of 493.0 F g −1 at 2.0 A g −1 and a retention ratio of 95.6% over 1000 cycles. Therefore, low magnetic fields may be an economic and effective tool in hydrothermal synthesis of MnO 2 electrodes for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Nanostructured MnO and MnO-FeO nanocomposites (MFO; x = 0.1, 0.2, and 0.3) have been synthesized through a low-temperature ball milling process followed by calcination and acid treatment. It was shown that both the post-annealing temperature and iron (Fe) concentration have a significant influence on the crystal structure and electrochemical performance of the MnO nanomaterial. The MnO-RT is exclusively γ-MnO, while the MFO is a mixture of α-MnO and FeO. In 1 M lithium hydroxide (LiOH) electrolyte, the MFO shows better performance as electrode material for supercapacitors than the MnO nanoparticles, indicating the beneficial effect of composite formation on the electrode performance. The specific capacitance of the MnO nanoparticles post-annealed at 200 °C (MnO-200 °C electrode) reaches an optimal value of 133.8 F g at 0.75 A g, while the MFO post-annealed at 200 °C (MFO-200 °C electrode) exhibits the highest value of 180.9 F g at 0.75 A g. After 500 cycles, the specific capacitances of the MnO-200 °C and MFO-200 °C electrodes keep 84.3 and 84.7 % of the initial capacity, respectively. The facile synthesis, high specific capacitance, and good cycle stability of such MFO electrodes enable their potential applications as electrode material in high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Ordered mesoporous carbon CMK-3 was successfully prepared by a hard template nanocasting method followed by carbonization at temperatures from 700 to 900 °C. The values of specific surface area, pore diameter and pore volume were found to increase with the rise of carbonization temperatures. After chemical activation by 6 M HNO 3 , the specific surface areas decreased significantly, but the specific capacitances increased remarkably in both alkaline (3 M KOH) and neutral (0.5 M Na 2 SO 4 ) electrolytes. Analysis of the surface structure and composition showed that the chemical activation introduced oxygen-containing functional groups on carbon surface, which are responsible for the enhancement of supercapacitive performances revealed by electrochemical tests. The best achieved specific capacitance is 182.1 F/g in 0.5 M Na 2 SO 4 , and 223.5 F/g in 3 M KOH, both at the current density of 0.5 A/g. The specific capacitance retentions after 500 cycles are 95.6% and 86.3% in 0.5 M Na 2 SO 4 and 3 M KOH, respectively. The higher specific capacitance in KOH electrolyte is due to the lower faradic charge transfer resistance and better electrochemical surface area utilization than in Na 2 SO 4 electrolyte. [ABSTRACT FROM AUTHOR]

• NiS Sodium lignosulfonate. • Activated carbon Composite electrode materials. • Cycle life Asymmetric supercapacitor. In this paper, NiS nanoparticles had been successfully loaded on activated carbon (AC) derived from sodium lignosulfonate via hexadecyl trimethyl ammonium bromide assisted hydrothermal method. Due to synergistic effects of AC and NiS nanoparticles, the conductivity of the NiS/AC electrode is significantly improved, and the composite electrode exhibits a high specific capacity (677 C/g at 0.5 A g−1) and excellent rate performance. Moreover, an asymmetric supercapacitor (ASC) device was assembled with the NiS/AC composite as positive electrode and the AC as negative electrode to evaluate the electrochemical performance of NiS/AC composites in practical applications. The ASC device achieves a maximum energy density of 45.6 Wh/kg at a power density of 509.5 W/kg, and excellent cycling stability with 92.6% of capacitance retention after 20,000 cycles. The electrochemical performance suggests that NiS/AC composites have great application prospect as electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]

AlCu x NiTiZr 0.75 high entropy alloy (HEA) films were deposited by magnetron sputtering with an alloy target in combination with a pure Cu metal target. The purpose of this study was to reduce electrical resistivity of the HEA films while maintaining mechanical properties and corrosion resistance by adjusting Cu content of the HEA. We found that the AlCu x NiTiZr 0.75 HEA films were amorphous and displayed a homogeneous or columnar microstructure along the cross sections. The increase of Cu content changed the electronic structure of the HEA films, so that the resistivity decreased sharply to 66 μΩ·cm at x = 1.4. The hardness-to-elastic modulus ration H/E, an indicator of a material's ductility, attained the maximum value at x = 1.4. Although the corrosion current densities increased with x , they were all below 10−6 A/cm2 in 3.5 wt% NaCl solution, indicating good corrosion resistance. These findings assumably help expand industrial application of HEA films, particularly when conductivity is required for the functionality of the films. • Amorphous AlCuxNiTiZr 0.75 high entropy alloy films were deposited by co-sputtering. • AlCuxNiTiZr 0.75 films maintained high hardness and good corrosion resistance. • The electronic structure of AlCuxNiTiZr 0.75 films were changed, and the lowest resistivity was 66 μΩ·cm. [ABSTRACT FROM AUTHOR]

Abstract: This paper develops a relative position and attitude estimation approach for satellite formation. A coupled relative translational dynamics is derived to represent orbital motion of arbitrary feature points on deputy, and the relative attitude motion is formulated by a rotational dynamics for no-gyro satellite. A position sensitive diode (PSD) sensor is used to provide multiple line-of-sight (LOS) vectors from a feature point to beacons fixed on the chief. The LOS measurements are coupled with dynamical models in an extended Kalman filter (EKF) to estimate relative attitude of the deputy and relative position of the feature point. Four different scenarios are simulated to validate that the estimation accuracy is affected by the beacons configuration and measurement distance. Through comparisons, the proposed approach is approved to provide high accurate relative attitude and position estimation for the no-gyro satellite. [Copyright &y& Elsevier]

• Surface energies of YF 3 are in the order of { 020 } < { 111 } < { 10 1 ¯ } < { 1 ¯ 02 }. • The Wulff shape of YF 3 is truncated octahedron, and may expose { 1 ¯ 02 } facets under extremely fluorine-lean conditions. • Inverse Wulff construction method is used to calculate the required surface energies that correspond to the experimentally observed shapes. Shape and size of YF 3 particles are determinant in hydrothermal synthesis experiments, whereas the surfaces' structural and thermodynamic parameters are largely unknown but are indispensable for further optimizations to the YF 3 micro- and nanocrystals. In this work we focus on {020}, {111}, { 10 1 ¯ } and { 1 ¯ 02 } facets that are frequently observed. For each orientation, structures and surface energies are obtained using density functional theory calculations. The surface energies are found to be in the order of { 020 } < { 111 } < { 10 1 ¯ } < { 1 ¯ 02 }. The Wulff shape is truncated octahedron, and may expose { 1 ¯ 02 } facets under fluorine-lean conditions. For other experimentally observed shapes (octahedron and diamond-like polyhedron), we present necessary modifications to the surface energies through the inverse Wulff construction method. The results are expected to be helpful in choosing surface-specific surfactants in synthesizing YF 3 crystals with targeted morphologies. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Multiple terminations of surfaces (10 1 ¯ 0) , (10 1 ¯ 1) , (11 2 ¯ 0) , and (0001) of Y(OH) 3 are established. • Effects of temperature and partial pressure of water and oxygen are included through first-principles thermodynamics. • The equilibrium morphology is of elongated hexagonal bipyramid enclosed by stoichiometric surfaces. Yttrium hydroxide Y(OH) 3 is an important precursor for yttrium oxides, and its morphologies are inherited by the yttrium oxides, thus affecting the products' properties and performance. Hydrothermally synthesized Y(OH) 3 particles are typically elongated hexagonal bipyramid, but thermodynamic parameters are inadequate for quantitative modeling of the morphology. We calculate surface energies and surface stresses of low-index orientations using density functional theory, and present a thermodynamic morphology model based on these parameters. We find that the thermodynamically stable surface terminations are always stoichiometric, and the surface energies are in the order of γ (10 1 ¯ 0) < γ (10 1 ¯ 1) < γ (11 2 ¯ 0) < γ (0001). The equilibrium morphology is of hexagonal prism capped by hexagonal pyramid enclosed by (10 1 ¯ 1) and (10 1 ¯ 0) surfaces. Because these terminations are stoichiometric, varying temperature or pressure is ineffective for modifying Y(OH) 3 particles' morphology, whereas surfactants should be used for this purpose in hydrothermal synthesis. Image, graphical abstract [ABSTRACT FROM AUTHOR]