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The construction of smart grid is an important part of improving the utilization rate of electric energy. As an important way for the construction of smart grid, non-intrusive load decomposition methods have been extensively studied. In this type of method, limited by transmission cost and network bandwidth, low-frequency data has been widely used in practical applications. However, the accuracy of device identification in this case faces challenges. Due to the relatively single characteristics of low-frequency data, it is difficult to express the operating status of complex electrical appliances, resulting in low decomposition performance. In this paper, a non-intrusive load is proposed based on household electrical habits by studying the relationship between household electricity consumption habits and load status decomposition method. The Gaussian mixture model and time information are used to model the probability distribution of the electrical appliance state. This probability distribution is then used as the observation probability distribution of the factor hidden Markov model. In such a way, the BH-FHMM model is proposed. Finally, load decomposition is carried out through the load decomposition process of the FHMM model. In order to verify the performance of the proposed method, an experimental comparison is conducted based on the REDD data set. According to the results, a significant improvement in equipment recognition accuracy is obtained. [ABSTRACT FROM AUTHOR]

• A solar-driven thermochemical reactor integrated with heat recovery is proposed. • A comprehensive coupled heat and mass transfer model is established. • Optimal reactor can achieve a solar-to-fuel efficiency of 10.58%. • The theoretical solar-to-fuel efficiency can reach as high as 40.43%. To cope with the increasingly serious energy crisis and environmental problems, the transformation from traditional energy to renewable energy is urgent. Solar-driven thermochemical conversion of CO 2 and H 2 O into renewable fuels technology provides a favorable path for alternative energy. However, the temperature/pressure swing required for the reduction and oxidation steps during thermochemical process incurs irreversible energy losses and severe material stresses. Moreover, the two-step redox cycle mode cannot achieve a continuous fuel production in the reactor. To address these issues, this study proposes a novel design of thermochemical reactor integrated with heat recovery for continuous production of renewable fuels. In this design, an oxygen-conducting ceria membrane is employed to conduct oxygen ions, electrons and vacancies induced by the oxygen chemical potential gradient to achieve an isothermal and continuous splitting of CO 2 and H 2 O. At the fuel production side, a counter-flow and tube-in-tube alumina reticulate porous ceramic filling heat exchange design is developed to recover the sensible heat of gas products and excessive reactants. In addition, a comprehensive model is developed by coupling the computational dynamics of flow, radiation, conduction and convection, and is solved by the Monte Carlo method coupled with ANSYS FLUENT software through User-defined Functions. Results indicate that the integrating membrane reactor/heat recovery design can not only realize continuous production of renewable fuels, but also recover sensible heat of gas products, which is beneficial for conversion of solar energy to chemical energy. Optimizing heat recovery design can help reactor achieve a solar-to-fuel efficiency of 10.58%. Moreover, if the theoretical CO 2 conversion rate could be achieved, the solar-to-fuel efficiency of reactor can reach as high as 40.43%, which means that such a reactor design has a huge potential in conversion of solar energy into renewable fuels. [ABSTRACT FROM AUTHOR]

The presence of Al and Si impurities from ultrapure magnetite concentrate (UMC) entering the lattice during the preparation of M-type strontium ferrite (SrM) has been a significant issue limiting the enhancement of magnetic properties in UMC- prepared SrM. In this article, the impact of CaCO 3 on the phase formation mechanism of synthesizing SrM using UMC is investigated. It is found that the formation of intermediate SrFeO 3−x phase and SrFe 12 O 19 phase shifts to the lower temperatures upon CaCO 3 addition. Lower calcination temperatures can inhibit excessive grain growth, thereby improving coercivity. At a calcination temperature of 1050 °C with the addition of 0.6 wt% CaCO 3 , the highest coercivity of 4672.29 Oe was achieved. Lattice parameters, magnetic properties, and micro-area composition analysis demonstrate that the addition of CaCO 3 reacts with Al impurities, preventing the incorporation of Al ions into the SrM lattice and promoting an increase in saturation magnetization. The highest saturation magnetization of 71.45 emu/g was obtained at the calcination temperature of 1200 °C. It has reached the level of magnetic properties of SrM prepared from Fe 2 O 3. CaCO 3 , being low-cost and environmentally friendly, can serves as an effective additive for improving the magnetic properties of UMC-prepared SrM without compromising its cost-effective and eco-friendly advantages. • SrFe 12 O 19 was synthesized from ultrapure magnetite concentrate as raw materials. • Adding CaCO 3 reduces the formation temperature of intermediate and final phases. • Adding CaCO 3 weakens the adverse effect of Al impurity of raw materials. • Adding CaCO 3 improves the magnetic properties of synthesized SrFe 12 O 19. • SrFe 12 O 19 is produced cheaply and environmentally. [ABSTRACT FROM AUTHOR]

Many experiments have shown that plastic deformation of metals generates heat, leading to temperature rise of the material. However, little is known about the underlying factors that govern the heat generation, especially in polycrystalline metals involving high-rate plastic deformation. In this work, the work-to-heat conversion during high-rate plastic deformation of polycrystalline coppers with and without nanotwins is studied using molecular dynamics simulations. The results show that within a certain range of imposed deformation, smaller grain size results in higher plastic work-to-heat conversion, due to larger proportion of grain boundaries. For a given grain size of polycrystalline copper with twins, the portion of plastic work converted to heat increases as the twin-boundary spacing decreases within a certain deformation range. However, at large deformation the plastic work-to-heat conversion coefficient should be analyzed specifically for each individual sample due to the transformation of the deformation mechanism (i.e., the change of the energy storage). [ABSTRACT FROM AUTHOR]

Counterexample models to the Nelson-Seiberg theorem have been discovered, and their features have been studied in previous literature. All currently known counterexamples have generic superpotentials respecting the R-symmetry, and more R-charge 2 fields than R-charge 0 fields. But they give supersymmetric vacua with spontaneous R-symmetry breaking, thus violate both the Nelson-Seiberg theorem and its revisions. This work proves that the other type of counterexamples do not exist. When there is no R-symmetry, or there are no more R-charge 2 fields than R-charge 0 fields in models with R-symmetries, generic superpotentials always give supersymmetric vacua. There exists no specific arrangement of R-charges or non-R symmetry representations which makes a counterexample with a supersymmetry breaking vacuum. This nonexistence theorem contributes to a refined classification of R-symmetric Wess-Zumino models. [ABSTRACT FROM AUTHOR]

[Display omitted] • The texture effect on void growth in heterogeneous polycrystals is investigated in a statistical manner. • The texture effect on void growth is strongly dependent on the loading mode. • The statistical void growth for Cube (resp. Brass) texture is always slower (resp. faster) than that for Random texture. • The void growth in textured polycrystals correlates with material flow stress. • A modified Rice-Tracey model is proposed to predict the void growth involving texture effect. Polycrystalline materials usually exhibit obvious preferred grain orientations (i.e., crystallographic texture) after rolling and heat treatments, leading to a certain crystalline anisotropy. However, most previous studies on microvoid growth generally treated the material as homogeneous isotropic matrix, ignoring the influence of crystallographic texture. In the present work, four typical crystallographic textures of face-centered cubic crystal are considered, including the Cube, Goss, Brass and Copper textures. Afterwards, the texture effect on microvoid growth is systematically studied by crystal plasticity finite element simulation, from a statistical point of view. In addition, the role of loading mode (i.e., uniaxial or biaxial tension) in the texture effect on microvoid growth has also been explored. The results indicate that the crystallographic texture evidently affects the statistical void growth in heterogeneous polycrystals, regardless of the loading mode. Meanwhile, it has been found that the statistical void growth of Cube (resp. Brass) texture is always slower (resp. faster) than that of random grain-orientation case. Furthermore, it is interestingly concluded that for the four considered textures, the trend of statistical void growth (from fast to slow) is well consistent with that of average flow stress (from high to low) at any given strain level, which cannot be captured by the classical Rice-Tracey model. Finally, based on the statistical characteristics of void growth for different textures, a statistical Rice-Tracey model incorporating the texture effect is established. It is demonstrated that this statistical model can well envelop all the dispersed void growth results of different textures for the uniaxial tensile loading. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Spinal cord trauma increases TREM1 expression in spinal cord tissue and TREM1 ablation attenuated motor function of mice after SCI. • TREM1-deletion reduces glial cells activation and inflammation in spinal cord tissue of SCI mice. • TREM1-deficiency alleviates oxidative stress in spinal cord tissue of SCI mice. Abstract Spinal cord injury (SCI) is a devastating event, leading to the progression of chronic neuropathic pain syndrome. Triggering receptor expressed on myeloid cells 1 (TREM1) is an innate immune receptor expressed on neutrophils and monocytes/macrophages. TREM1 enhances inflammatory response in various models of diseases, but its significance in SCI remains unclear. In the present study, we attempted to explore the effects of TREM1 on the regulation of SCI. Spinal cord contusion injury was performed in wild type (WT) and TREM1-knockout (TREM1KO) mice, and real time-quantitative PCR (RT-qPCR), western blot, and immunofluorescent (IF) staining were used to calculate TREM1, inflammation and oxidative stress in spinal cord tissues 42 days after SPII. In vitro, astrocytes (AST) and BV2 cells were transfected TREM siRNA or the negative control (NC) siRNA to knockdown (KD) TREM1 expressions, followed by lipopolysaccharide (LPS) stimulation to verify the role od TREM1 in modulating SPI. The results suggested that TREM1 was highly expressed in the spinal cord tissues of WT mice after SCI. TREMKO mice exhibited improved locomotor function, mechanical and thermal hypersensitivity in the hindpaws after SCI. In addition, peripheral nerve injury-related biomarkers were down-regulated by TREM1KO in SCI mice. TREM1KO increased NeuN-stained cells, and decreased GFAP and Iba-1 expressions in spinal cord tissues of mice after SCI. TREM1KO mice showed reduced expressions of inflammation-related regulators in the injured spinal cord. Further, toll like receptors (TLR-2, -3, -4, and -9), p-IκBα and p-nuclear factor-kappa B (NF-κB) protein expression levels were markedly decreased by TREM1KO in mice after SCI injury. Moreover, TREM-deficiency suppressed oxidative stress markers, while enhanced anti-oxidants, such as superoxide dismutase-1 (SOD1), NAD(P)H:quinone oxidoreductase-1 (NQO-1), heme oxygenase-1 (HO-1) and nuclear factor E2–related factor 2 (Nrf2) in the injured spinal cord. The in vivo results mentioned above were verified in LPS-stimulated AST and BV2 cells in vitro. Of note, the in vitro results also demonstrated that suppressing HO-1 expressions using Zn-protoporphyrin (ZnPP) abrogated TREM1KD-reduced inflammation, oxidative stress and glial cells activation. The results above demonstrated that suppressing TREM1 expressions markedly improved the outcome of SCI, most likely through reducing inflammation and oxidative stress at least partly regulated by HO-1 expressions. TREM1 inhibition might be therefore has potential as a therapeutic target after SCI. [ABSTRACT FROM AUTHOR]

Highlights • Cylindrical system of vector functions. • Transversely isotropic diffusive bimaterials. • General concentrated dislocations and diffusive source. • Analytical Green's function solution. • Effect of diffusive coefficients on the dislocation field. Abstract While the fundamental solutions of concentrated forces and dislocations in purely elastic media are available for various applications, solutions in the corresponding diffusive materials have seldom been derived due to the involved complexity. In this paper, in terms of the cylindrical system of vector functions and under the assumption of steady-state deformation, we derive analytically the elastic and diffusive fields induced by the concentrated forces and dislocations which are located on the interface of a transversely isotropic and diffusive bimaterial space. Solution of the concentrated diffusive source has been also derived. These solutions can further be reduced to the corresponding isotropic bimaterial case and the transversely isotropic full-space case. Based on the newly derived solutions, field quantities induced by different concentrated dislocation sources are presented numerically to demonstrate the effect of the diffusive coefficients, material heterogeneity, and dislocation types on the induced fields. [ABSTRACT FROM AUTHOR]

Abstract A two-dimensional elastic solution for the stress field of a line dilatation near a circular inhomogeneity is obtained. A line dilatation is used to represent a row of solute atoms, referred to as a solute rod. The image effect is investigated with an especial attention. It is shown that a soft inhomogeneity attracts solute rods and a hard inhomogeneity repels solute rods. Based on this, the interactions of solute atoms with inhomogeneity-edge dislocation are studied by inserting more solute atoms into the matrix one-by-one, with an especial focus on the distribution of solute atoms (rods) around inhomogeneity and edge dislocation. As two typical applications of the present method, two simple cases are analyzed in details, with the inhomogeneity considered as a nano-void and a hard nano-fiber, respectively. It is shown that the equilibrium concentration distribution of solutes near an inhomogeneity is non-local, which not only depends on the local hydrostatic stress but also on the hydrostatic stress in the adjacent region. Besides, the shear stress on an edge dislocation, generated by hydrogen atmospheres between a circular nano-void/fiber and the dislocation, is calculated numerically. The results show that the hydrogen atmosphere around dislocations can shield the long-range elastic interaction between dislocations and other internal stress sources, supporting the so-called hydrogen enhanced localized plasticity. Graphical abstract Image 1 Highlights • A 2-D elastic solution for stress field of a line dilatation near internal stress sources is given. • The elastic inhomogeneity-dislocation-solute interaction is studied. • The solute atmospheres influences heavily the inhomogeneity-edge dislocation interaction. • The hydrogen enhanced localized plasticity mechanism is supported. [ABSTRACT FROM AUTHOR]

Open-cell metal foam has been increasingly applied in heat exchangers to enhance heat transfer. In this work, the coupled radiation-convection in a rectangular channel filled with metal foam under constant wall temperature is simulated numerically. Discrete-scale approach (DSA) and continuum-scale approach (CSA) are respectively developed for the simulation. In DSA, foam domain is constructed through numerous Kelvin structures, and pore scale field is obtained via CFD simulation with re-radiation flux calculated by surface to surface model; while in CSA, local thermal non-equilibrium model (LTNE) is employed with Monte Carlo method to solve radiative heat transfer, and volume-averaged correlations are determined based on Kelvin structure. The flow field and heat transfer at pore-level generated from DSA are analyzed. By means of a representative volume-averaged post-processing method, thermal behaviors from DSA and CSA are compared in terms of pertinent parameters. It shows that spatial fluctuation phenomenon is observed in pore-level temperature field. The overall heat transfer performance characterized by local Nusselt number is enhanced by inclusion of thermal radiation, and the effect is significant for lower pore density and higher porosity case. Increasing the inlet velocity, pore density or decreasing the porosity all can lead to heat transfer enhancement more or less. For all the cases studied, DSA and CSA can predict the temperature field consistently while the discrepancy between them is relatively larger in the local thermal non-equilibrium region. Additionally, it reveals that CSA is not applicable for accurately predicting energy transport in large gradient heat transfer region due to its volume-averaged characteristic. [ABSTRACT FROM AUTHOR]

• The size- and stress-dependent dislocation-DLs interactions are investigated by MS and MD, with the emphasis focused on its kinetic effect. • The dislocation tends to fully absorb/transform small DLs but only to partially absorb/transform large ones. • When the dislocation is accelerated to subsonic speed, abnormal "pull-forward" configurations can be formed after it bypasses the small DLs. • The kinetic effect decreases the CRSS of dislocation bypassing DLs evidently. • Both amended DBH and BKS hardening models are proposed to consider the above kinetic effect. In this paper, the interaction between an edge dislocation and irradiation <100> sessile self-interstitial atom (SIA) type dislocation loops (DLs) is studied by atomistic simulations in BCC Ta at 0 and 300 K. Both molecular dynamics (MD) and statics (MS) simulations are performed to highlight the dislocation kinetic effect (or dynamic effect) on the critical resolved shear stress (CRSS) for dislocation bypassing the DLs and on the dislocation-SIA DLs interaction mechanisms. The simulation results show that the dislocation-DLs interaction mechanisms are two-fold. When the DL size is lower than a critical value, the moving edge dislocation tends to completely absorb the DLs or fully transform the original DLs into other-type ones. However, when the DL size is higher than the critical value, the moving dislocation tends to absorb or transform the DLs partially or even marginally. Moreover, with increasing applied shear stress, the high-speed dislocation has no sufficient time to absorb SIAs from DLs, which also changes the dislocation-DLs interaction process remarkably. When the dislocation is accelerated to subsonic, an abnormal "pull forward" dislocation configuration may present upon the dislocation bypasses a small DL. More importantly, with the kinetic effect considered, the CRSS for dislocation overcoming the barriers of DLs decreases significantly for the dislocation-DLs interaction mechanisms. In order to appropriately describe the kinetic effect on the CRSS, amended dispersed barrier hardening (DBH) and Bacon-Kocks-Scattergood (BKS) hardening models for the latter dislocation-DLs interaction mechanism are proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

Polyphenylene sulfide (PPS) hydrophobic micro-porous flat sheet membranes were fabricated with diphenyl ketone (DPK) and benzoin (BZ) as mixed diluent via thermally induced phase separation (TIPS). It was found that the mass ratio of DPK/BZ had a strong influence on the structure and property of PPS membranes. As DPK content increased, the interaction between PPS and diluents reduced linearly and the membrane micro-structures changed from honeycomb, bi-continuous to spherical particle structure via liquid-liquid (L-L) phase separation process. Herein, the prepared PPS micro-porous membranes were used in vacuum membrane distillation (VMD) for the first time, and they showed the strong hydrophobicity and high salt rejection ratio. Especially, the membrane prepared from the mixed diluent of 15 wt% DPK and 85 wt% BZ with the bi-continuous network structure and Berberis thunbergii var. atropurpurea Chenault leaf-like structure achieved the maximum permeate flux of 22.8 L/m −2 h −1 and the highest salt rejection of 99.99%. Most importantly, the membrane with Berberis thunbergii var. atropurpurea Chenault leaf-like leaf structure performed excellent long-term stability in corrosive water membrane distillation (MD) experiment (3.5 wt% NaCl and 10 wt% NaOH as feed solution). Those results show the potential application of this novel type of membrane in the treatment of corrosive sewage. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • PDA/PEI modified PPS membrane is resistant to acid, alkali and organic solution. • Modified membrane prevents dye from interacting with S to result in high rejection. • High rejection is due to Donnan exclusion, intermolecular reaction and size sieving. • The modified PPS membrane has preferable anti-fouling property. Abstract A novel coating with stable and excellent wettability is architecturally constructed on the surface of polyphenylene sulfide (PPS) membrane via co-deposition with polyethyleneimine (PEI) and mussel-inspired polydopamine (PDA), which has critical significance for PPS membrane with excellent separation performance and service durability. The modified membrane exhibits the better acid-base resistance property, due to the cross-linking reaction between catechol and amino. The continuous filtration experiment of methyl blue (MLB) and Rhodamine B (RhB) at 180 min shows that PDA/PEI modified membrane has the higher dye rejection (>99.0%) than unmodified membrane because the modified membrane prevents dye molecules from interacting with the sulfur atom in the microporous surface of PPS membrane. After three sequential cycles, the modified membranes still exhibit the high rejection for RhB and good flux recovery ratio (>95%), indicating that the modified membrane has higher anti-fouling property. Most importantly, the modified membrane also exhibits the high rejection of MLB in organic solution filtration process, indicating the modified membrane has good solvent resistance. The high rejection performance of modified PPS membrane is mainly due to the synergistic effect of Donnan exclusion, inter-molecular reaction and size sieving. Therefore, the PDA/PEI modified PPS membrane is not only a new candidate membrane for dye rejection, but also it is expected to be a good organic solvent resistant membrane which can be used under some harsh environmental conditions. [ABSTRACT FROM AUTHOR]

The deformation mechanisms in the α-Fe twist bi-crystals (TBCs) containing differently angled twist grain boundaries (TGBs) are investigated carefully using the molecular dynamics modeling, with especial concerns on how solute hydrogen affects them. The results show that there are three main deformations in the TBCs, i.e. the dislocation glide-dominated mechanism, the twining-dominated mechanism, the dislocation glide and twining co-dominated mechanism, depending upon both the twist angle and the loading direction. In the dislocation glide-dominated TBCs, solute hydrogen increases the dislocation nucleation strength, dislocation mobility and dislocation density, further increases the vacancies concentration due to frequent interactions of solute hydrogen atoms with dislocations. In the dislocation glide and twining co-dominated TBCs, the solute hydrogen has weaker effect on the increase of dislocations density and the decrease of twins fraction with increasing tensile strain. However, in the twining-dominated TBCs, solute hydrogen assists the deformation twinning but doesn't increase significantly the vacancies concentration. So, it seems that twinning deformation is beneficial to resist hydrogen embrittlement (HE). These knowledge is helpful for us to understand the HE mechanism and develop new hydrogen-resistant high-strength materials. [ABSTRACT FROM AUTHOR]

The shock responses of crystalline Ni with two types of symmetric tilt grain boundaries (STGBs) are studied by large-scale molecular dynamics simulations, with special concerns on the effect of hydrogen segregated STGBs on them. The crystalline Ni with different kinds of H-free STGBs have significantly different plastic responses during the shock processes due to different mechanisms of dislocation emission from the STGBs. The segregation of hydrogen atoms at the STGBs significantly affects the dislocation emission from the H-segregated STGBs, and then heavily affects the shock plastic responses of crystalline Ni with H-segregated STGBs. On the one hand, dislocation emission from the H-segregated STGBs is delayed compared with that from the H-free ones at the low shock velocity, showing the so-called lagging effect. On the other hand, multi-mode dislocation emissions (or dislocation emission on the multi slip systems) are frequently activated from the H-segregated STGBs at the high shock velocity. In addition, the spallation behavior of the crystalline Ni under shock loading is also significantly affected by hydrogen segregation at the STGBs. In the targets with the H-free STGBs, spallation originates mainly from the interior of the grains due to strong interaction and reaction between dislocations there, however, it originates definitely from the H-segregated STGBs due to the reduced GB cohesive strength by hydrogen segregation. [ABSTRACT FROM AUTHOR]

Biomass product 5-hydroxymethylfurfural (5-HMF) can be used to synthesize a broad range of value added compounds currently derived from petroleum. Thus, the effective conversion of glucose or cellulose (the major components of biomass) into fuels and chemical commodities has been capturing increasing attention. Previous studies have been extensively focused on a two-step process for producing 5-HMF from glucose or cellulose, i.e., the isomerization of glucose into fructose and then the dehydration of fructose. We herein discovered that heterogeneous sulfonated poly(phenylene sulfide) (SPPS) containing strong Brønsted acid sites is able to convert glucose and cellulose into 5-HMF with a high yield in ionic liquids (ILs). The optimal activity of glucose conversion to 5-HMF achieves a yield of 87.2% after 4 h reaction at 140 °C. For direct cellulose conversion, a 5-HMF yield of 68.2% can be achieved. The reaction mechanism over the SPPS catalyst in ILs was studied by DFT calculations, and the results indicated that the SO3H group of SPPS plays a crucial role in glucose conversion into 5-HMF, and it acts as a proton donor as a Brønsted acid and functions as a proton acceptor as the conjugate base. Furthermore, the anions and cations of ILs together with SO3H-SPPS helped in stabilizing the reaction intermediates and transition states, which also resulted in glucose facile conversion into 5-HMF. The new catalyst system highlights new opportunities offered by optimizing the production of 5-HMF directly from glucose and cellulose. [ABSTRACT FROM AUTHOR]

In this study, Poly(p-phenylene sulfide) (PPS) microporous membrane was prepared via Thermally Induced Phase Separation (TIPS), and the superhydrophilic membrane was modified by nitric acid. After the interfacial reaction between PPS membrane and HNO 3 , a large number of hydrophilic groups, such as SO , SO 2 , C O, NH 2 and NO 2 groups, were introduced onto PPS membrane surface. When the treatment temperature was 50 °C, the characterized results indicated that the membrane became superhydrophilic with contact angle of 0° and pure-water flux of 154.95 L/m 2 h. And the membrane structure was not destroyed during the modification via HNO 3 . Furthermore, the performance of modified membrane on oil/water separation was studied and all of the separation efficiency were greater than 95% when the modified membrane was utilized to separate four different types of oil/water emulsions. In particular, the modified membrane was utilized to separate the chlorobenzene/water emulsion with the separation efficiency of 98.98%. Both carbonic ink solution and 1 wt% chlorobenzene/water emulsion were filtered with the treated membrane with acid/base solution (pH = 1, 7 and 14) to evaluate the modified membrane corrosion resistance of acid/base, and the characterized results indicated that modified membrane possessed the excellent acid/base corrosion resistance. [ABSTRACT FROM AUTHOR]

Due to trapping of hydrogen atoms to vacancy, vacancy-Hydrogen complex exists dispersively in materials working in hydrogen environment and influences significantly the dislocation mobility, rendering so-called hydrogen embrittlement. The interactions between a moving edge dislocation and vacancy-Hydrogen complexes or clusters in α - Fe are studied carefully in this paper by atomistic modelling. Our results show that vacancy and vacancy cluster are stable and easier to grow due to their lower formation energy and binding energy with the help of trapped H atoms. When approaching a vacancy-H complex, the edge dislocation is first attracted and in most cases pinned by the complex. The pinning strength of a vacancy-H complex or cluster on the edge dislocation increases with the increasing number of hydrogen atoms trapped in vacancy or vacancy cluster. The critical shear stress for an edge dislocation de-pinning from the vacancy-H complex can be described by a de-pinning equilibrium equation. The inherent pinning mechanism mainly originates from the migration of H atoms in vacancy or vacancy cluster when it is cut by the moving edge dislocation. These results will be helpful for further understanding of the hydrogen induced deformation and failure. [ABSTRACT FROM AUTHOR]

TiO 2 (B) nanotubes and anatase TiO 2 were synthesized, and the transesterification of dimethyl carbonate (DMC) with phenol and its derivative bisphenol A (BPA) were carried out over them. When reaction was carried out over TiO 2 (B) nanotube at 150 °C, phenol conversion obtained 7.8% and transesterification selectivity reached 99.8%. As reaction temperature increased to 170 °C, phenol conversion came up to 54.6% and transesterification selectivity can still maintain a good yield at 99.2%. When bulk BPA reacted with DMC at 150 °C, transesterification selectivity and BPA conversion reduced to 92.4% and 3.9%. Raising temperature to 170 °C, BPA conversion increased to 43.4%, but transesterification selectivity declined to 90.3%. However, the transesterification of DMC with phenol and BPA took place at 150 °C over anatase TiO 2 , the transesterification selectivity significantly declined to 92.7% and 76.1%, and phenol and BPA conversion only achieved 5.1% and 3.0%. The higher activity of TiO 2 (B) nanotubes in transesterification was due to its larger surface area, higher pore size and more structure defects. Importantly, in situ DRIFT and TG–MS were used to characterize DMC adsorption, activation and decomposition process over TiO 2 (B) surface, which provided more information about the mechanism of transesterification and methylation. [ABSTRACT FROM AUTHOR]

The bending resistance of multi-cell square tubes under three-point bending is investigated in this study. Partition plates are introduced in longitudinal direction and cross-section of square tubes to form multi-cell structures. Numerical simulation of the three-point bending test is carried out by nonlinear finite element code and experimental test is conducted to validate the numerical model. Parametric studies are then performed to investigate the influence of the number of cells, load conditions and other geometrical configurations on the bending resistance. Results reveal that the number of partition plates has important influence on the bending resistance of the structure and more partition plates do not necessarily lead to high energy absorption efficiency. The optimum configurations of the structures are found out and some valuable suggestions are offered for multi-cell structures under transverse loading. [ABSTRACT FROM AUTHOR]

To study the assistance of growth twin in nano-layered polycrystalline metallic multilayers to their strength, a series of uniaxial tensile modeling of nano-twinned Cu//Ag and Cu//Ni multilayers is performed via molecular dynamics method, with especial attentions to the influence of the twin lamella thickness and its spatial distribution on the strengthening mechanism. The results indicate that the strengths of nano-twinned multilayers can be enhanced significantly by introducing nano-twin lamellae into them and show strong twin thickness effect. By checking the atomic details, it is found there exists a critical twin lamella thickness above which the deformation mechanism of metallic multilayers is the hairpin-like partial dislocation gliding dominated and below which it becomes the necklace-like multiple jogged dislocation gliding dominated, however. The formation and transition of different deformation mechanisms are discussed in detail and analyzed theoretically, and the effect of the distinct deformation mechanisms on the strength of multilayers is also depicted quantitatively. In addition, the strengths and deformation mechanisms of two type nano-twinned Cu//Ag multilayers with non-uniform twin lamellae distribution are also discussed. The results show that the necklace-like dislocation mechanism and the hairpin-like dislocation mechanism can coexist in those non-uniform twinned multilayers and the necklace-like multi-jogged extended dislocations are unexpectedly observed in thicker twin lamellae. Although there are synergetic interactions between two mechanisms, the strengths of multilayers with non-uniform nano-twin lamella thickness can be well predicted by the rule of mixture. [ABSTRACT FROM AUTHOR]

Aqueous Zn ion batteries with cost-effectiveness, high safety, and eco-friendliness have a great potential as an excellent substitute for non-aqueous cells for large-scale energy storage. However, the intercalation of Zn2+ ions in the cathode materials is challenging and complex due to the sluggish diffusion kinetics of Zn2+ ions. Herein, the highly reversible Zn ion battery based on vanadium oxide nanobelts has been developed by using pre-inserted bimetallic ions (Na+ and Ca2+ ions) within the vanadium oxide layer (NCVO) as the cathode and Zn(CF 3 SO 3) 2 solution as an electrolyte. Vanadium oxide nanobelts which were calcined at 350 °C (NCVO-350) deliver the superior cycle stability with a capacity retention rate close to 100% after 200 cycles at 0.5 A g−1, and 92% retention is also achieved after 3000 cycles at 10 A g−1. The ultrahigh capacity retentions at low/high current densities are attributed to the pre-inserted bimetallic ions within the layers to enhance the structural stability of the vanadium oxide nanobelts. Moreover, the low-cost electrode material preparation process will accelerate the industrialization of aqueous Zn ion batteries. [Display omitted] • A simple solution impregnation method at ambient conditions is proposed. • The conversion of vanadium-based materials from nanoparticles to nanobelts. • Amorphous structure of electrode also can enhance Zn-storage performances. • Bimetallic ions nanobelts exhibit promising electrochemical performance. [ABSTRACT FROM AUTHOR]

Nucleus pulposus (NP) apoptosis and subsequent excessive degradation of the extracellular matrix (ECM) are key pathological characteristics of intervertebral disc degeneration (IDD). The present study aims to examine the signaling processes underlying the effects of taurine on IDD, with specific focus on endoplasmic reticulum (ER) stress-mediated apoptosis and ECM degradation, in NP cells. To clarify the role of taurine in IDD, NP cells were treated with various concentrations of taurine and IL-1β or thapsigargin (TG). Cell Counting Kit-8, western blotting, TUNEL, immunofluorescence assays and reverse transcription-quantitative PCR were applied to measure cell viability, the expression of ER stress-associated proteins (GRP78, CHOP and caspase-12), apoptosis and the levels of metabolic factors associated with ECM (MMP-1, 3, 9, ADAMTS-4, 5 and collagen II), respectively. Taurine was found to attenuate ER stress and prevent apoptosis in NP cells induced by IL-1β treatment. Additionally, taurine significantly decreased the expression of ER stress-activated glucose regulatory protein 78, C/EBP homologous protein and caspase-12. TUNEL results revealed that taurine decreased the number of apoptotic TG-treated NP cells. TG-treated NP cells also exhibited characteristics of increased ECM degradation, supported by observations of increased MMP-1, MMP-3, MMP-9 and A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5 expression in addition to decreased collagen-II expression. However, taurine treatment significantly reversed all indicators of excessive ECM catabolism aforementioned. These data suggest that taurine can mediate protection against apoptosis and ECM degradation in NP cells by inhibiting ER stress, implicating therapeutic potential for the treatment of IDD. [ABSTRACT FROM AUTHOR]

This paper studies the stress field and crack nucleation behavior in a disclinated nanowire with a continuum model. The surface stress effects of the nanowire is accounted for with the Gurtin-Murdoch model. The Green's functions for the stress fields of a single wedge disclination and a single edge dislocation in a cylindrical nanowire are solved respectively with the complex variable method. To make the superposition principle valid, the stress field induced by the residual surface tension is properly handled in the Green's functions. After that, the distributed dislocation method is applied to simulate the crack nucleation behavior. The influences of the surface stress effects on the stress fields of the wedge disclination and edge dislocation as well as on the Griffith crack nucleation behavior are systematically discussed. [ABSTRACT FROM AUTHOR]

The mechanical behavior of a polycrystalline aluminum in tension was modeled using a climb-assisted discrete dislocation dynamics (DDD) technique. Special focus was on how dislocation climb influences the flow stress of the polycrystalline aluminum with regard to selected grain sizes at elevated temperature. A periodical representative cell (PRC) consisting of given number of grains was used in the simulations. Results showed that, at the high temperature considered, dislocation climb plays an important role in defining the mechanical behavior of the polycrystalline crystal. Specifically, dislocation climb decreases significantly the flow stress and hardening rate while increases the dislocation density by relieving the dislocation pile-ups against the grain boundaries (GBs). In addition, the grain size effect on the yield stress of polycrystalline aluminum is significantly weakened by dislocation climb, especially when the grain size falls in the range of submicron. Another interesting result is that, at high temperature, when both dislocation climb and glide are considered, the grain size effect seems to be insignificant with regard to the applied strain rate, although the strength of material increases with enhanced loading rate. [ABSTRACT FROM AUTHOR]

• We systematically investigate the conversion of plastic work to heat in high-rate shear deformation using molecular dynamics simulations. • Dislocation nucleation and glide are the main mechanisms of plastic heat dissipation in shear deformation. • Both Schmid's law and the non-Schmid effect have an influence on the microscopic mechanism of heat dissipation, in which Schmid's law still occupies a dominant influence. • Although temperature rise and stress during shear deformation depend on crystal orientation, work-to-heat conversion coefficient does not depend on crystal orientation. Almost all plastic work in shear deformation is converted into heat. The conversion of work into heat is one of the most significant characteristics of plastic deformation, especially in a high strain rate regime. The quantitative characterization of the fraction of plastic work converted into heat plays a crucial role in understanding the deformation process and mechanism and establishing an accurate and reasonable thermomechanical constitutive model. However, the fraction of plastic work converted into heat is experimentally found to span over a wide range of values between 0.1 and 1. In this paper, the conversion of plastic work into heat in high-rate shear deformation is systematically investigated through the relations between temperatures, stresses, elastic and plastic strains using molecular dynamics simulation. The results show that the temperature rise in the shear deformation is caused by the heat dissipation of the plastic work rather than the thermo-elastic coupling effect due to invariance of the volume. Dislocation nucleation and glide are the main mechanisms of shear deformation and are also the origins of heat generation. The continuous slip of dislocations also results in the formation of deformation twins. Interestingly, the work-to-heat conversion coefficient is revealed to be independent of crystal orientation, in contrast to the plastic deformation itself. From the present study, we conclude that almost all the plastic work in shear deformation is converted into heat dissipation for all studied samples. [ABSTRACT FROM AUTHOR]

Abstract: We found that the esterification of l-glutamic acid by benzyl alcohol is greatly promoted by CuCl2 even in H2O solvent, and the selectivity and yield of γ-benzyl ester of l-glutamic acid achieved 100% and 95.31%. Metal cation coordination to the amino acids via neighboring amino and carbonyl groups increased α position carboxyl acidity which initiates the esterification reaction to selectively take place on γ position carboxyl group. In this autocatalytic process H2O has no effect on esterification. [Copyright &y& Elsevier]

Highlights: [•] The SISF dissociation scheme is introduced into the present 3D-DDD framework. [•] The two typical stages of the APB-SISF transition are successfully captured. [•] The results considering SISF and APB dissociations are closer to experiments. [Copyright &y& Elsevier]

The coupled effects of sample size and grain size and the plastic deformation mechanisms of polycrystalline Al nanowires were investigated by molecular dynamics. With the number of grains across the diameter increasing from one to four, the 5nm grain size nanowires showed a “smaller is stronger” effect, the 10nm grained nanowires did not show any significant size effect, while the 20nm grained nanowires showed a “smaller is weaker” effect. Different size effects are induced by competition between surface-mediated and grain boundary-mediated deformations. [Copyright &y& Elsevier]

Abstract: To reveal the intrinsic strengthening mechanism in Ni-based single crystal superalloy, the interaction between matrix dislocations and interfacial misfit dislocation networks was modeled in this contribution via molecular dynamics (MD) method. Our results show that the role of interfacial dislocation networks is very complex. On the one hand, the interfacial dislocation networks can act as dislocation sinks to absorb/accommodate the matrix dislocations. During the accommodation process of matrix dislocation by the networks, both the interfacial Lomer–Cottrell locks and a[100] dislocation junctions are formed, which stabilize and strengthen the interfacial dislocation networks. On the other hand, the interfacial dislocation networks can provide dislocation pins to prevent the matrix dislocations from cutting into the γ′ precipitate. These matrix dislocation segments pinned at the phase interface can serve as Frank–Read sources with their length being about half of the dislocation network spacing, providing an explanation for the effect of dislocation network spacing on the creep strength of the Ni-based single crystal superalloy. [Copyright &y& Elsevier]

Abstract: Organotin oxide was used to catalyze the reaction between BPA (bisphenol A) and DMC (dimethyl carbonate), and Ph2SnO (diphenyltin oxide) displays the excellent catalytic performance in transesterification and O-methylation. However, Bu2SnO (dibutyltin oxide), (PhCH2)2SnO (dibenzyltin oxide) and (C6H11)2SnO (dicyclohexyltin oxide) exhibited weaker catalytic activity but higher selectivity for C-methylation product formation. The π–π function between Ph2SnO and BPA provided more chances for their interaction, and π–d interaction between phenyl ring and Sn resulted in catalyst having higher activity in transesterification and O-methylation. O-methylation product formation over Ph2SnO comes from transesterification product decomposition not from direct methylation of BPA with DMC. [Copyright &y& Elsevier]

The compressive behavior of hollow micropillars is modeled by three-dimensional discrete dislocation dynamics (3D-DDD). Computational results show that wall thickness is the principal geometrical parameter governing the compressive strength of these micropillars, while inner or outer diameter has a weak influence. This is because the plastic behavior is dominated by the single-arm dislocation sources with statistical lengths determined by the wall thickness. The single-arm source model is further extended to quantitatively describe this thickness effect, showing good agreement with the present 3D-DDD results. [Copyright &y& Elsevier]

The compressive properties of two single- and bicrystalline micropillars are comparatively modeled through three-dimensional discrete dislocation dynamics. A dislocation-penetrable pure tilt grain boundary (GB) model is especially taken into account in the bicrystalline micropillar. Different intermittent plastic behaviors of these two micropillars compressed in a displacement-controlled manner are computationally captured. The underlying mechanisms are discussed and detailed comparisons with experiments are also made. [Copyright &y& Elsevier]

Abstract: P-methyl acetephenone synthesis from toluene and acetic anhydride over HPW(H3PW12O40)/TiO2 was carefully studied, and catalysts were characterized by BET, XRD and NH3-TPD. The characterized results displayed that the interaction between HPW and TiO2 prevented the loss of acidic protons from HPW to form the weak Lewis acid sites over HPW/TiO2. The weak acid sites over HPW/TiO2 came into being in case of much more HPW being loaded onto TiO2 or HPW/TiO2 being calcined at high temperature. The reaction results suggest that p-methyl acetephenone yield and selectivity depended on the acidity of catalysts, and the appearance of weak Lewis acid sites over HPW/TiO2 resulted in p-methyl acetephenone yield decline. [Copyright &y& Elsevier]

Abstract: Two-methylcarbonate-ended-BPA (DmC(1)) was selectively synthesized from dimethyl carbonate (DMC) and bisphenol A (BPA) over organotin modified SBA-15. Organotin modified samples were characterized by XRD, FT-IR, BET and TG, and the relations between catalytic performance and catalyst properties were discussed. When heterogeneous SBA-15(CH2)3SnOC4H9 was used as catalyst, DmC(1) achieved better yield and higher selectivity than that obtained over homogeneous (C4H9)2SnO. The confined region effect of SBA-15(CH2)3SnOC4H9 was the main reason to promote the reaction between one-methylcarbonate-ended-BPA (MmC(1)) and DMC. [Copyright &y& Elsevier]

Abstract: The uniaxial tension behavior of polycrystalline thin films, in which all grain boundaries (GBs) are penetrable by dislocations, is investigated by two-dimensional discrete dislocation dynamics (DDD) method with a penetrable dislocation-GB interaction model. In order to study thickness effect on the tensile strength of thin films with and without surface treatment, three types of thin films are comparatively considered, including the thin films without surface treatment, with surface passivation layers (SPLs) of nanometer thickness and with surface grain refinement zones (SGRZs) consisting of nano-sized grains. Our results show that thickness effects and their underlying dislocation mechanisms are quite distinct among different types of thin films. The thicker thin films without surface treatment are stronger than the thinner ones; however, opposite thickness effects are captured in the thin films with SPLs or SGRZs. Moreover, the underlying dislocation mechanisms of the same thickness effects of thin films with SPLs and SGRZs are different. In the thin films with SPLs, the thickness effect is caused by the sharp increase of dislocation density near the film-passivation interface, while it is mainly due to the sharp decrease of dislocation density within the refined surface grains of the thin films with SGRZs. No matter in what type of thin films, thickness effect gradually disappears when the number of grains in the thickness direction is large enough. Our analysis reveals that general mechanism of those thickness effects lies in the competition between the exterior surface-constraint and interior GB-constraint on gliding dislocations. [Copyright &y& Elsevier]

Abstract: The cylindrical nano-indentation on metal film/elastic substrate is computationally studied using two-dimensional discrete dislocation plasticity combined with the commercial software ANSYS®, with a focus on the storage volume for geometrically necessary dislocations (GNDs) inside the films and the nano-indentation size effect (NISE). Our calculations show that almost all GNDs are stored in a rectangular area determined by the film thickness and the actual contact width. The variations of indentation contact width with indentation depth for various film thicknesses and indenter radii are fitted by an exponential relation, and then the GND density underneath the indenter is estimated. Based on the Taylor dislocation model and Tabor formula, a simple model for the dependence of the nano-indentation hardness of the film/substrate system on the indentation depth, the indenter radius and the film thickness is established, showing a good agreement with the present numerical results. [ABSTRACT FROM AUTHOR]

Abstract: MCM-41 was grafted with 3-aminopropyl trimethoxysilane (APTMS), 3-chloropropyltriethoxysilane (CPTMS) to give organic group modified samples, and l-tryptophane was covalently immobilized onto organic samples to improve the physicochemical properties of mesoporous silica to controlled amoxicillin delivery. Samples were characterized by X-ray diffraction (XRD), N2 adsorption–desorption isotherms and Fourier transform infrared (FT-IR) spectroscopy, and characterized results demonstrated that organic groups were successfully grafted onto the samples. The results of amoxicillin release exhibited that 12.9wt% and 33.0wt% impregnated amoxicillin could be released from the post-grafting MCM-41 with APTMS and pure MCM-41 after 24h, however, 41.0wt% impregnated amoxicillin could be released from the post-grafting MCM-41 with CPTMS after 24h. When the samples modified with APTMS and CPTMS were further grafted by l-tryptophane, the slower drug release rate was achieved over samples with l-tryptophane immobilization. The release profiles of all samples indicated that the amoxicillin release was mainly regulated by the diffusion mechanism. [Copyright &y& Elsevier]

Abstract: Carboxymethylated species were selectively synthesized from dimethyl carbonate (DMC) and bisphenol A (BPA) over TiO2/SBA-15. On the basis of catalyst characterization by means of XRD, FT-IR, HPLC and GC–MS, the relations between catalytic performance and catalyst properties were discussed. Si–O–Ti was active sites for reaction, and the interaction mode between Ti–O–Si and DMC was main factor to determine carboxymethylation and methylation. When DMC was attacked by Ti–O–Si on two oxygen atoms of CH3–O moiety, BPA attacked carbonyl carbon to form carboxymethylated products. If the interaction occurs through the oxygen of C BPA attacked methyl carbon to form methylated products. Chemisorbed H2O over TiO2/SBA-15 made DMC to act as methylating agent. After chemisorbed H2O was removed, carboxymethylated species of two-methylcarbonate-ended-BPA (DmC(1)) and one-methylcarbonate-ended-BPA (MmC(1)) were selectively synthesized. [Copyright &y& Elsevier]

Abstract: 2D discrete dislocation dynamic modeling of compressed micro-pillars attached on a huge base is executed to study the size-dependent microplastic behavior of micro-pillars and the corresponding size effect. In addition to the conventional dimensional parameters of the micro-pillar such as the micro-pillar size and the height-to-width ratio, the micro-pillar taper angle and the dislocation slip plane orientation angle in the micro-pillar are also considered to address the size effect and its rich underlying mechanism. Computational results show that there are at least two operating mechanisms responsible for the plastic behavior of micro-pillars. One is associated with the dislocation free slip-out from the micro-pillar sidewall; the other is related to the dislocation pile-up at the base and the top end of the pillar. The overall mechanism governing the size effect of the micro-pillar rests with multi-factors, including the micro-pillar size, the height-to-width ratio, the micro-pillar taper and the slip plane orientation angle; however, whether the “free slip band” exists or not is the most important denotation. The well-known Schmid law still validates in the slender micro-pillars due to existence of the free slip band, whereas it may fail in the podgier micro-pillars due to absence of the free slip band; as a result, a complicated even “reverse” size effect appears. [Copyright &y& Elsevier]

Abstract: The grain-size effect on the yield stress and the flow strength in micro-polycrystals relates closely to the penetrability of grain boundary (GB) to dislocations. To simulate the dislocation transmission across grain boundary, a dislocation–grain boundary penetration model is proposed and then integrated into the two-dimensional discrete dislocation dynamics (DDD) framework by Giessen and Needleman (1995). By this extended DDD technology, the Hall–Petch effect in micro-polycrystals and the strengthening mechanism are computationally studied, with the main focus on the significant influence of the dislocation transmission across grain boundary that is not fully considered formerly. Results indicate that the Hall–Petch type relation is still applicable, but depends strongly on the GB-penetrability to dislocations, especially for the flow strength at large offset strains. The fitting values of Hall–Petch grain-size sensitive exponents n for initial yield stress and flow stress basically agree with experimentally measured data in published literatures. [Copyright &y& Elsevier]

Abstract: The debenzylation of benzyl phenyl ether (BPE) and its derivatives with acetic anhydride over zeolite was investigated. HY9 displayed the high activity in BPE debenzylation due to its high molar ratio of Lewis acid sites to Brönsted acid sites (L/B). Debenzylation also depended on the substituent attached to the aromatic ring of pheoxide. Electron-releasing substituent promoted benzyl group migration onto aromatic ring. However, electron-drawing substituent was in favor of the oxygen of ether to be attacked by acetylium ions into debenzylation products. In addition, the effects of reaction temperature and time on BPE debenzylation were also studied. [Copyright &y& Elsevier]

Abstract: Nanoindentation has been extensively used to measure the mechanical behavior of materials at the micro- and nanoscale. However, the material response of nano/microindentation and its intrinsic mechanisms are very complicated, especially when considering heterogeneous polycrystalline materials. In this contribution, nanoindentation in polycrystals, performed with a circular indenter, is studied by numerical modeling based on the two-dimensional discrete dislocation plasticity of Van der Giessen and Needleman [Van der Giessen E, Needleman A. Model Simul Mater Sci Eng 1995;3:689]. The dependence of indentation hardness is investigated with respect to four typical characteristic dimensions: indenter radius, grain size, indentation depth, and the distance between the grain boundary and the indenter. Results show that these characteristic dimensions have considerable influence on the nanoindentation hardness. Further investigation shows that their influence takes effect mainly in two ways, i.e. via strain hardening and the indentation size effect. Although both effects are size dependent, their underlying mechanisms are clearly different. For the present polycrystal case, the strain hardening effect is mainly associated with the constraints of grain boundaries and dislocation obstacles to the dislocation glide, while the indentation size effect is related to the average strain gradient beneath the circular indenter. [Copyright &y& Elsevier]

Abstract: The mesoporous catalyst activities of supported molybdenum oxide for diphenyl carbonate (DPC) synthesis in liquid-phase transesterification of dimethyl carbonate (DMC) and phenol were investigated. The yields of DPC and methyl phenyl carbonate (MPC) were greatly improved when MoO3 was supported on SiMCM-41 to act as catalyst. MoO3/SiMCM-41 catalysts were characterized by X-ray diffraction (XRD), N2 adsorption–desorption isotherms, and Fourier transform infrared (FT-IR) spectroscopy. Characterized results revealed that the high activity sites of MoO3/SiMCM-41 were isolated MoO4 2− tetrahedral species and polymerized octahedral molybdenum oxide species. MPC formation increased with reaction time up to 4h and then decreased thereafter, and maximum MPC yield achieved 39.6%. The decrease of MPC yield after 4h might be ascribed to MPC disproportionation into DPC and reversible transesterification reaction. [Copyright &y& Elsevier]

Abstract: The cyclic plastic response of a single crystalline thin beam subject to combined cyclic tension and bending is analyzed using two-dimensional discrete dislocation plasticity. In this contribution, special attention is paid to the difference in the inherent mechanism of the size effect for different cyclic loads. Results show that the cyclic plastic response has a strong size effect for both cyclic pure tension–compression and pure bending. However, the inherent mechanisms are different. The dislocation starvation mechanism dominates the cyclic tension–compression while the geometrically necessary dislocation dominates the cyclic pure bending. When the combined cyclic tension and bending are applied to the thin beam, the cyclic moment–rotation response shows strong size effect while the stress–strain response shows weak or even no size effect. In addition, it is also found that the cyclic loading paths have considerable influences on the shape of the cyclic stress–strain loops. [Copyright &y& Elsevier]

Abstract: MClχ/SiMCM-41 was prepared by impregnation and its behaviors on the decomposition of CCl4 into diphenyl carbonate (DPC) were examined. The maximum DPC yield of 20.7% was obtained when ZnCl2 was supported on SiMCM-41 with 35% loading. ZnCl2/SiMCM-41 was characterized by XRD and N2 adsorption–desorption isotherms, and the characterized results showed that ZnCl2 was highly dispersed on SiMCM-41 and ZnCl2/SiMCM-41 had high BET surface area. The main reasons for ZnCl2/SiMCM-41 displaying the higher activity than any other MClχ/SiMCM-41 might be the zero ligands field stabilized energy (LFSE) and strong Lewis acid of Zn (II). [Copyright &y& Elsevier]

Abstract: The systematic investigation was carried out to elucidate the direct reaction between CO2 and phenol over multiphase catalyst. Reactions carried out over ZrO2, TiO2, and KF/NaY+Mn2+ gave the high selectivity to 4-[4-hydroxybenzyl]phenol and 2-[2-hydroxybenzyl]phenol (HBP), and the maximum HBP selectivity of 68% was obtained with ZrO2 as catalyst. XRD patterns showed that metastable tetragonal ZrO2 was the active phase for HBP synthesis, and the bidentate carbonate on ZrO2 surface was responsible for high HBP selectivity. If Hbeta, HZSM-5, and Al2O3 were used as catalyst, the main product was diphenyl ether (DPE). But when reactions were catalyzed by KY and KF/NaY, xanthone became the main product; however, xanthone disappeared when KF/NaY coexisted with Mn(OCOCH3)2 as catalyst. The optimized reaction conditions for HBP synthesis over tetragonal ZrO2 are 350°C, 12h, and 4.0MPa CO2 pressure. [Copyright &y& Elsevier]

Abstract: Synthesis of diphenyl carbonate (DPC) from phenol and CO2 has been explored in CCl4 with zinc halides as catalyst. DPC yield and selectivity are influenced by the catalyst usage, reaction temperature, CO2 pressure and initial composition of reactants. The main byproduct is phenyl salicylate (PS). Zinc halides as Lewis acid exhibit high catalytic activity for DPC synthesis; ZnCl2 gives higher DPC yield and selectivity than ZnBr2 and ZnI2. High DPC yield was obtained with ZnCl2 as catalyst at 120°C and 4.0MPa. Based on the experimental observation, a possible reaction scheme has been proposed. The electronegativity of halogen ligand may determine the formation of DPC and PS; the Cl ligand in ZnCl2 with strong electronegativity may favor the formation of DPC. [Copyright &y& Elsevier]

Abstract: In the present paper, an infinite face-centered cubic single crystal containing an isolated cylindrical micron-sized void, which is subjected to proportional and monotonically uniform equal biaxial tension loading, is adopted to study the scale-dependent void growth and its intrinsic mechanism by employing a two-dimensional planar discrete dislocation dynamic framework. First, a typical dislocation distribution near the microvoid is presented and the void growth mechanism is revealed by dislocation shear loop expansion for each of three typical fcc slip systems. The effect of size on void growth is then investigated. The general conclusion that voids at the micron or submicron scale are less susceptible to growth than larger ones is drawn. Another result, which cannot be deduced from the continuum theories, is also achieved: at the micron or submicron scale, larger voids grow smoothly with remote strain, while smaller voids usually grow in a “leapfrog” manner. Specifically, when the void is even smaller, it grows in an approximately linear-elastic manner since only few dislocations are present around the void. Further analyses indicate that these size effects are closely related to the dislocation density on the void surface and the dislocation mobility around the void. Finally, the influences of the dislocation sources/obstacles density and their random distribution in materials on the void growth are studied briefly. Results show that there exists remarkable scatter in the microvoid growth due to random distribution of the dislocation sources or obstacles, especially for voids at the submicron scale. These results are helpful for us in understanding the size-dependent damage mechanism at the micron or submicron scale. [Copyright &y& Elsevier]