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Phase change material (PCM) based thermal energy storage (TES) is an important solution to the waste of heat and intermittency of new energy sources. However, the thermal conductivity of most PCMs is low, which severely affects the thermal energy storage performance. Oscillation of the tube bundles in a TES unit can intensify the convection of liquid PCM and, therefore, enhance heat transfer. However, the energy storage performance of bundled-tube TES systems in response to oscillation at different amplitudes and frequencies has not been well understood yet, and the optimum time to apply the oscillation during phase transition remains unexplored. To address this issue, this present study was carried out. First, the melting behaviour of PCM with oscillation starting at different times was investigated. Then, the influences of oscillation frequency and amplitude on the melting performance were explored. Finally, the solidification behaviour of PCM with oscillation starting at different times was examined. Results show that the oscillation can accelerate the phase transition process by enhancing convective heat transfer. Compared to the case without oscillation, the complete melting and solidification times are reduced by 8.2 and 6.7% for the case with oscillation starting at 200 s, respectively. The effect of oscillation frequency on the melting enhancement is negligible, while the oscillation amplitude has an important effect on the melting enhancement. [ABSTRACT FROM AUTHOR]

In an effort to synthesize chemically recyclable thermoplastic elastomers, a redox‐switchable catalytic system was developed to synthesize triblock copolymers containing stiff poly(lactic acid) (PLA) end blocks and a flexible poly(tetrahydrofuran‐co‐cyclohexene oxide) (poly(THF‐co‐CHO) copolymer as the mid‐block. The orthogonal reactivity induced by changing the oxidation state of the iron‐based catalyst enabled the synthesis of the triblock copolymers in a single reaction flask from a mixture of monomers. The triblock copolymers demonstrated improved flexibility compared to poly(l‐lactic acid) (PLLA) and thermomechanical properties that resemble thermoplastic elastomers, including a rubbery plateau in the range of −60 to 40 °C. The triblock copolymers containing a higher percentage of THF versus CHO were more flexible, and a blend of triblock copolymers containing PLLA and poly(d‐lactic acid) (PDLA) end‐blocks resulted in a stereocomplex that further increased polymer flexibility. Besides the low cost of lactide and THF, the sustainability of this new class of triblock copolymers was also supported by their depolymerization, which was achieved by exposing the copolymers sequentially to FeCl3 and ZnCl2/PEG under reactive distillation conditions. [ABSTRACT FROM AUTHOR]

In an effort to synthesize chemically recyclable thermoplastic elastomers, a redox‐switchable catalytic system was developed to synthesize triblock copolymers containing stiff poly(lactic acid) (PLA) end blocks and a flexible poly(tetrahydrofuran‐co‐cyclohexene oxide) (poly(THF‐co‐CHO) copolymer as the mid‐block. The orthogonal reactivity induced by changing the oxidation state of the iron‐based catalyst enabled the synthesis of the triblock copolymers in a single reaction flask from a mixture of monomers. The triblock copolymers demonstrated improved flexibility compared to poly(l‐lactic acid) (PLLA) and thermomechanical properties that resemble thermoplastic elastomers, including a rubbery plateau in the range of −60 to 40 °C. The triblock copolymers containing a higher percentage of THF versus CHO were more flexible, and a blend of triblock copolymers containing PLLA and poly(d‐lactic acid) (PDLA) end‐blocks resulted in a stereocomplex that further increased polymer flexibility. Besides the low cost of lactide and THF, the sustainability of this new class of triblock copolymers was also supported by their depolymerization, which was achieved by exposing the copolymers sequentially to FeCl3 and ZnCl2/PEG under reactive distillation conditions. [ABSTRACT FROM AUTHOR]

Surface energy in nanomaterials is an essential parameter demonstrating a key role in their surface interactions and their functionalization aptitude. In this work, a new and facile methodology based on atomic force microscopy for the measurement of the surface energy of single-walled carbon nanotubes (SWCNTs) is reported. The proposed approach starts with the calibration based on a well-studied material, graphite, and the precision of the technique is confirmed by the measurement of the surface energy of multiwalled carbon nanotubes. Our measurements show that SWCNTs display a surface energy of 52.8 mJ/m2, which is in very good agreement with theoretical predictions of the measured property. Our experimental approach is essentially applicable to other nano-objects in contrast to conventional wet angle methods which are currently employed mainly in bulk materials. [ABSTRACT FROM AUTHOR]

Super-high dielectric constant (k) AlOx/TiOy nanolaminates (ATO NLs) are deposited by an atomic layer deposition technique for application in next-generation electronics. Individual multilayers with uniform thicknesses are formed for the ATO NLs. With an increase in AlOx content in each ATO sublayer, the shape of the Raman spectrum has a tendency to approach that of a single AlOx layer. The effects of ATO NL deposition conditions on the electrical properties of the metal/ATO NL/metal capacitors were investigated. A lower deposition temperature, thicker ATO NL, and lower TiOy content in each ATO sublayer can lead to a lower leakage current and smaller loss tangent at 1 kHz for the capacitors. A higher deposition temperature, larger number of ATO interfaces, and higher TiOy content in each ATO sublayer are important for obtaining higher k values for the ATO NLs. With an increase in resistance in the capacitors, the ATO NLs vary from semiconductors to insulators and their k values have a tendency to decrease. For most of the capacitors, the capacitances reduce with increments in absolute measurement voltage. There are semi-circular shapes for the impedance spectra of the capacitors. By fitting them with the equivalent circuit, it is observed that with the increase in absolute voltage, both parallel resistance and capacitance decrease. The variation in the capacitance is explained well by a novel double-Schottky electrode contact model. The formation of super-high k values for the semiconducting ATO NLs is possibly attributed to the accumulation of charges. [ABSTRACT FROM AUTHOR]

The impact of a chief executive officer's (CEO's) functional experience on firm performance has gained the attention of many scholars. However, the measurement of functional experience is rarely disclosed in the public database. Few studies have been conducted on the comprehensive functional experience of CEOs. This paper used the upper echelons theory and obtained deep-level curricula vitae (CVs) data through the named entity recognition technique. First, we mined 15 consecutive years of CEOs' CVs from 2006 to 2020 from Chinese listed companies. Second, we extracted information throughout their careers and automatically classified their functional hierarchy. Finally, we constructed breadth (functional breadth: functional experience richness) and depth (functional depth: average tenure and the hierarchy of function) for empirical analysis. We found that a CEO's breadth is significantly negatively related to firm performance, and the quadratic term is significantly positive. A CEO's depth is significantly positively related to firm performance, and the quadratic term is significantly negative. The research results indicate a u-shaped relationship between a CEO's breadth and firm performance and an inverted u-shaped relationship between their depth and firm performance. The study's findings extend the literature on factors influencing firm performance and CEOs' functional experience. The study expands from the horizontal macro to the vertical micro level, providing new evidence to support the recruitment and selection of high-level corporate talent. [ABSTRACT FROM AUTHOR]

The ohmic contact resistance (${R}_{C}$), surface resistance (${R}_{S}$), and channel resistance (${R}_{\text {CH}}$) of hydrogen-terminated diamond (H-diamond) MOSFETs were investigated in this study. Planar-type and T-type H-diamond MOSFETs were employed to analyze them. Because no interspaces exist between the source–drain and gate electrodes for the T-type H-diamond MOSFETs, then ${R}_{S}$ is zero. Both planar-type and T-type MOSFETs show low leakage current densities and good operations. By considering the relationships between the total resistance (${R}_{ \mathrm{\scriptscriptstyle ON}}$) and 1/ $\vert $ gate voltage-threshold voltage $\vert $ , ${R}_{C}$ and ${R}_{\text {CH}}$ for the T-type H-diamond MOSFET at a gate voltage of −10.0 V are determined to be 13.8 and 21.8 $\Omega \cdot $ mm, respectively. As ${R}_{C}$ for both MOSFETs is the same, ${R}_{S}$ and ${R}_{\text {CH}}$ for the planar-type H-diamond MOSFET are deduced to be 90.0 and 15.8 $\Omega \cdot $ mm, respectively. ${R}_{S}$ accounts for 75.3% of ${R}_{ \mathrm{\scriptscriptstyle ON}}$ for the planar-type H-diamond MOSFET, which is the main reason for its lower drain current and extrinsic transconductance than those of the T-type MOSFET. Although ${R}_{S}$ is suppressed for the T-type H-diamond MOSFET, ${R}_{C}$ occupies 38.8% of ${R}_{ \mathrm{\scriptscriptstyle ON}}$. To further improve the performance of the H-diamond MOSFETs, it is important to eliminate ${R}_{S}$ and decrease ${R}_{C}$ to further improve the electrical properties of the H-diamond MOSFETs. [ABSTRACT FROM AUTHOR]

• A novel porous structure based on truncated cuboctahedron is proposed. • The novel porous structure better enhances PCM melting near the porous cell corners. • A critical porosity exists to determine the enhancement advantages of two different porous structures. • The critical porosity is decreased with the increase of pore density. Metallic porous structure is a prevailing heat transfer enhancer for the melting of phase change material (PCM), while the effect of the structure on the enhancement performance is yet to be understood. In this work, a pore-scale numerical study on PCM melting embedded in a truncated cuboctahedron porous structure, referred as TCD metal foam, was performed. The solid–liquid interface, temperature and the variation of liquid fraction were analyzed and compared with those with the tetrakaidecahedron porous structure, referred as TKD metal foam. The effects of natural convection, porosity, pore density and heating temperature are explored. It is found the natural convection shortens the PCM melting time by about 7 % with the considered porosity range and thus cannot be ignored. Results also show that the TCD metal foam better enhances PCM melting near the porous cell corners compared to the TKD metal foam. Further analysis shows the TCD metal foam can better enhance melting at the former stage due to the larger surface area, while the TKD metal foam can better enhance melting at the later stage due to the thicker metallic ligaments. With essentially the same melting time at ɛ = 0.941, the half-melting takes 17.2 % of the complete melting time for TCD metal foam and 20.3 % of the complete melting time for TKD metal foam. A critical porosity value exists when comparing the enhancement performance of these two metal foams, below which the better melting enhancement is shifted from the case with TCD metal foam to the case with TKD one. The critical porosities are 0.941, 0.923 and 0.899 at the pore densities of 10, 20 and 30 PPI respectively. [ABSTRACT FROM AUTHOR]

Boron-doped diamond (B-diamond) metal–oxide–semiconductor (MOS) capacitor and MOS field-effect transistor (MOSFET) are fabricated on a flat diamond epitaxial layer. Their electrical properties and thermal stabilities after annealing at 500 °C are investigated. Annealing makes the leakage current density of the B-diamond MOS capacitor increase slightly. There is a larger stretch-out for the capacitance-voltage curve in the depletion region after annealing than that before annealing. The drain-current maxima for the as-fabricated and 500 °C-annealed MOSFETs are obtained as −0.49 and −0.60 mA/mm, respectively. Extrinsic transconductance maxima are 18.7 and $21.4~\mu \text{S}$ /mm, respectively. These obtained values are considerably larger than those obtained by the previously reported B-diamond MOSFETs. [ABSTRACT FROM AUTHOR]

The mechanical property of roof is critically important for underground coal mining activities. The existence of hard roof that cannot cave naturally after coal extraction results in an unconsolidated goaf with large voids, and the sudden failure of this type of roof in uncontrolled manner will cause server windblast or rockburst hazard. To address this hazard, pre-existing fractures are created in roof by hydraulic fracturing or blasting to weaken the hard roof and promote its natural caving. The effectiveness of these roof weakening techniques is highly dependent on the geometry of pre-conditioned fractures and its impact on the mechanical behaviour of combined roof-coal strata, which has not been well-explored yet. Therefore, 21 groups of uniaxial compression testing on combined rock-coal specimens with pre-existing cracks were carried out, and the effect of fracture length and angle on the mechanical properties and failure modes of combined rock-coal strata were investigated. It can be concluded that longer cracks and/or cracks with angle closer to 30° tend to have the following characteristics. (1) The more gentle the stress-strain curve of the combined coal and rock tends to be, the larger the decrease range of its elastic modulus, peak strength and peak strain, and the smaller the strain interval corresponding to the elastic-plastic stage. The results show that the artificial fracture weakens the mechanical properties of composite coal and accelerates the process from micro-crack to macro failure. (2) When the specimen enters the plastic stage, the acoustic emission jumps sharply; the cumulative number of micro-cracks and the cumulative energy released during the whole loading process gradually decrease, and the number of micro-cracks and the released energy at the moment of failure also decrease gradually. (3) The crack-initiating stress for combined coal-rock specimens gradually decreases via one of three typical modes: preferential crack initiation of coal, simultaneous crack initiation of combined coal-rock and preferential crack initiation of rock, which also matches with coal failure, rock-coal failure and rock failure in the combined specimens. Thus, to promote the continuous fracture of the roof under loading, the length and orientation of the pre-conditioned cracks must be controlled and optimised. [ABSTRACT FROM AUTHOR]

A super-high dielectric constant AlO x /TiO y nanolaminate film i s grown on hydrogenated diamond (H-diamond) to enable superior metal-oxide-semiconductor (MOS) capacitors and MOS field-effect transistors (MOSFETs). In order to minimize or suppress leakage current, a nanometer thick AlO x film is inserted at the AlO x /TiO y nanolaminate/H-diamond interface. The maximum values for the capacitance density and dielectric constant related to the summation of individual AlO x and nanolaminate are 1.06 μF/cm2 and 68.7, respectively. Capacitance density and dielectric constant for the AlO x /TiO y nanolaminate are as high as 5.22 μF/cm2 and 308, respectively. Electrical properties of four H-diamond MOSFETs with gate lengths increasing from 2.4 μm to 10.1 μm were investigated. All of them showed p-type behavior and distinct pinch-off characteristics with drain current maxima of −47.4, −43.3, −26.6, and −24.6 mA/mm, respectively. On/off ratios and threshold voltages for the MOSFETs are higher than 104 and lower than 0.55 ± 0.10 V, respectively. The low threshold voltages indicate that the AlO x /TiO y nanolaminate gate-based MOSFETs can switch between ON and OFF stages at low gate voltages. Effective mobilities of the H-diamond channel layers for all the MOSFETs raised firstly and dropped subsequently with increasing voltages, which can be explained by the effect of mobility limiting factors. We demonstrate that super-high dielectric constant AlO x /TiO y nanolaminate film on diamond enables superior MOS capacitors and MOSFETs for a new generation of micro/nanoelectronics. Image 1 [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to investigate the influence of different post-annealing cooling conditions, i.e. furnace cooling (heat treatment (HT) 1 – slow cooling) and air cooling (HT 2 – fast cooling), on the microstructure and mechanical properties of selective laser melting (SLM) built austenitic 316L stainless steel (SS). Design/methodology/approach: Three sets of 316L SS samples were fabricated using a machine standard scanning strategy. Each set consists of three tensile samples and a cubic sample for microstructural investigations. Two sets were subsequently subjected to annealing HT with different cooling conditions, i.e. HT 1 and HT 2, whereas one set was used in the as-built (AB) condition. The standard metallographic techniques of X-ray diffraction, scanning electron microscopy and electron back-scattered diffraction were used to investigate the microstructural variations induced by different cooling conditions. The resultant changes in mechanical properties were also investigated. Findings: The phase change of SLM fabricated 316L was observed to be independent of the investigated cooling conditions and all samples consist of austenite phase only. Both HT 1 and HT 2 lead to dissolved characteristic melt pools of SLM. Noticeable increase in grain size of HT 1 and HT 2 samples was also observed. Compared with AB samples, the grain size of HT 1 and HT 2 was increased by 12.5% and 50%, respectively. A decreased hardness and strength, along with an increased ductility was also observed for HT 2 samples compared with HT 1 and AB samples. Originality/value: From previous studies, it has been noticed that most investigations on HT of SLM fabricated 316L were mainly focused on the HT temperature or holding time. However, the post-HT cooling rate is also an equally important factor in deciding the microstructure and mechanical properties of heat-treated components. Therefore, this paper investigates the influence of different post-annealing cooling conditions on microstructure and mechanical properties of SLM fabricated 316L components. This study provides a foundation for considering the post-HT cooling rate as an influential parameter that controls the properties of heat-treated SLM components. [ABSTRACT FROM AUTHOR]

Here, thermal stabilities for Ohmic contact properties of Pt, Au, and Pd on the same hydrogen-terminated diamond (H-diamond) epitaxial layer are investigated. A long-term annealing process is performed with an annealing temperature and time of 400 °C and 8 h, respectively. Before annealing, good Ohmic contact properties are observed for only two contacts of the Pt/H-diamond and Pd/H-diamond with specific contact resistivity (ρC) values of 2.7 × 10−3 Ω cm2 and 2.6 × 10−4 Ω cm2, respectively. After long-term annealing, all three contacts on the H-diamond show good Ohmic contact properties. The ρC values for the Pt/H-diamond and Au/H-diamond are 3.1 × 10−2 Ω cm2 and 4.2 × 10−4 Ω cm2, respectively. They are higher than that of the Pd/H-diamond (1.1 × 10−4 Ω cm2). Therefore, low ρC and good thermal stability for the Pd/H-diamond are achieved. This is meaningful for pushing forward the development of H-diamond-based electronic devices for high-temperature applications. [ABSTRACT FROM AUTHOR]

In this article, we report the fabrication and characterization of boron-doped diamond (B-diamond) Schottky diodes and MESFETs. Effects of annealing at 573–973 K on the electrical properties of these devices are investigated. Current density maximum for the as-fabricated Schottky diode is 0.05 A/cm2 at a gate voltage of −10.0 V. Annealing at 673 and 973 K makes it increase first to 0.70 A/cm2 and decrease lately to 0.07 A/cm2, respectively. ON/OFF ratios for the as-fabricated B-diamond Schottky diode exceed 4.5 × 108 at the OFF-voltage (VOFF) of 0 V and 3.2 × 106 at VOFF = 42.0 V. For the annealed Schottky diode, the ON/OFF ratios are higher than 1.7 × 106 at VOFF < 6.0} V. Ideality factor and barrier height for Au/Pt bilayer gates on the B-diamond channel layer range from 1.05 to 1.78 and from 1.24 to 1.56 eV, respectively. All three B-diamond MESFETs with the gate lengths of 12.0, 7.0, and 4.3 μm, respectively, operate with p-type channel characteristics. The drain current maxima for the as-fabricated MESFETs are −0.11, −0.16, and −0.39 mA/mm. After annealing at 773 K, these values increase to −0.17, −0.24, and −0.55 mA/mm. Annealing at 773 K also increases the extrinsic transconductance maxima for the three MESFETs from 11.1, 11.0, and 10.4μS/mm to 18.6, 16.2, and 14.4 μS/mm, respectively. [ABSTRACT FROM AUTHOR]

Existing research shows that acoustic BG in a certain frequency range can be realized by installing an expansion chamber on duct system, but the problems of broadband and size limitations at low frequencies remain to be researched. The study of acoustic and elastic wave propagation in artificial periodic structures has received increasing attention for many decades, and the presence of bandgap (BG) in phononic crystals (PCs), which inhibits elastic/acoustic wave propagation within the BG' frequency range, supplies a new way to control noise and vibrations in duct system. Based on PC theory, a duct silencer backed with a gas–liquid expansion chamber is proposed to enhance the acoustic performance of low-frequency noise attenuation. The transfer matrix method (TMM) is used to investigate the acoustic BG properties. The influences on the BG properties of some key parameters are analyzed, and the band formation mechanism is revealed by the law of energy conservation. The results show that silencers with a small size can effectively attenuate ultra-low frequencies and ultra-broad bands. [ABSTRACT FROM AUTHOR]

Highlights • The embedded mechanism of oligopeptides by β-CDs has been clarified in detail. • Multiple calculations and experiments illustrate the mechanism together. • β-CDs prefer to embed the aromatic rings of oligopeptides. • Quantum-chemical results demonstrate the H-bonding forces existing in the complex. Abstract Herein, we perform the regioselective acetylation of phloridzin catalyzed by immobilized Candida antarctica lipase B (CALB). We show that the enzyme amount and reaction time can significantly influence the composition of mono-, di- and tri-acetylated phloridzin in the product. The last acetylated derivative of phloridzin is isolated and identified as 4, 3″, 6″-3-O-acetyl-phloridzin by HPLC, UV, IR, MS and NMR. Molecular docking suggests that the first acetylation of phloridzin catalyzed by CALB occurs in 6″-OH, followed by 3″-OH, then 4-OH. During this process, hydrogen bond and hydrophobic forces play an important role in maintaining the binding interaction of CALB with phloridzin or its acetylated derivatives. Although, tri-acetylated phloridzin has moderate to minimal adverse-effects on LO-2, its anti-proliferative activity against human HepG2 cancer cells is superior to that of phloridzin, which attributes to its high capacity of inducing cell apoptosis, retarding cell cycle, lowering mitochondrial membrane potential and scavenging intracellular ROS. [ABSTRACT FROM AUTHOR]

Summary: An appropriate design of solar thermal power plant (STPP) is important before construction. This present study attempted to deal with some fundamental questions in design of STPP. What is the relationship between the optimal design direct normal irradiance (DNI) and weather conditions? What is the optimal solar multiple for a STPP at a specific weather condition? How does the thermal energy storage (TES) affect the electricity output of STPP, and how does dispatch fraction affect the usage of stored thermal energy? To help answer these questions, a general model was built and a critical design DNI was proposed from the perspective of effective use of solar energy. There will be solar energy wasting if the design DNI is below the critical design DNI, while the power block will not be effectively used if the design DNI is above the critical design DNI. This critical design DNI can be used to determine the optimal solar multiple for a given design DNI. The effects of TES size and dispatch fraction on the critical design DNI were also discussed. A critical design direct normal irradiance was proposed in this study from the perspective of effective use of solar energy with considering weather condition, thermal energy storage, and dispatch strategy. The critical design direct normal irradiance can demonstrate solar energy usage ability of a solar thermal power plant, and it can also help to determine the solar multiple at a given weather condition. [ABSTRACT FROM AUTHOR]

The employment of annular fins and longitudinal fins in latent heat thermal energy storage unit can significantly improve its thermal performance. However, the annular fins can greatly suppress the convection and longitudinal fins lead to severe non-uniform melting. To address this issue, three different types of combinational fins were proposed and applied in a vertical shell-tube storage unit in this study. The numerical model was first built with the adoption of enthalpy-porosity method. The simulation results were then verified with experimental data. Results showed that combinational fins leads to faster melting thorough enhancing both natural convection and conduction compared with only longitudinal or annular fins. This advantage in melting enhancement is even greater with the increase of fin volume. Moreover, the enhancement effect of combinational fins is better with the same longitudinal and annular fins volume and a higher longitudinal fin at the same longitudinal fin volume. The optimum combinational fins in present work has a melting time reduction of 31.0% and 21.2% compared with only longitudinal and annular fins, respectively. The results can provide important reference for the fins design in vertical shell-tube thermal energy storage units. [ABSTRACT FROM AUTHOR]

• T-shaped fin can enhance heat conduction and convection of PCM at the bottom region. • The horizontally and vertically arranged T-shaped fins outperforms other designs. • T-shaped fins reduce about 1/3 of melting time regardless of HTF temperature and fin volume. • A length ratio of vertical to horizontal portion greater than 1.0 can better enhance the melting performance. Enhancing the melting performance of phase change material (PCM) has always been an important issue in thermal energy storage. T-shaped fin has the potential to enhance melting as it has much larger heat transfer surface away from heat source compared to traditional longitudinal plate fin. However, its enhancement performance remains unexamined. This study examined the effect of T-shaped fins on PCM melting in a horizontal shell-and-tube storage unit. The melting enhancement performance of four T-shaped fins was compared with that of eight longitudinal plate fins which have the same total fin volume with T-shaped fins. The results showed that T-shaped fins can significantly enhance the melting process by shortening the complete melting time and improving the melting uniformity regardless of the heat transfer fluid (HTF) temperature. Compared to longitudinal plate fins, horizontally and vertically arranged T-shaped fins save 34.5% melting time, while the T-shaped fins having a 45° angle with horizontal direction save only 8% melting time. The lengths of the vertical and horizontal portions were further optimized to improve the melting performance. It is found T-shaped fins with a length ratio of vertical to horizontal portion greater than 1.0 can better enhance the melting performance, and a length ratio of 1.33 saves 47.1% melting time compared to the longitudinal plate fins. [ABSTRACT FROM AUTHOR]

Abstract: During apple processing, phloridzin, the main flavonoid in apples, can be oxidized to the yellow pigment, which contributes to the color of apple juice and ciders. However, there was no report about the bioactivities of this yellow pigment. In this study, the oxidation of phloridzin catalyzed by tyrosinase from mushroom was investigated. The main oxidation product with bright yellow color was purified and identified as the phloridzin oxidation product j (POPj) based on electrospray ionization mass spectrometry (ESI‐MS) and 13C nuclear magnetic resonance (13C‐NMR) spectroscopy. In the chemical and cellular system, POPj exhibited the higher peroxyl radical‐scavenging activity than phloridzin. Our results suggested that POPj was a kind of potential food yellow pigment with antioxidant activity, which partly explained health‐promoting functions of apple juices and ciders. Practical applications: In view of the potential toxicity of the artificial food yellow pigment, the need for natural and safe yellow pigment is increasing. In this study, the enzymatic preparation of the yellow pigment derived from phloridzin was investigated. Its antioxidant activity was first reported. This study can prompt the application of this new yellow pigment in food industry. [ABSTRACT FROM AUTHOR]

A 3D multi-layer model with Gaussian profile was developed to investigate the thermal and mechanical behaviors of plasma sprayed NiCrBSi coatings during manufacturing. The coating growth was simulated by activating progressively the corresponding elements layer by layer, while the heat contributions of sprayed particles and of the impinging plasma jet were assumed as heat fluxes applied on the surface of the substrate or of the previously deposited layers. Thus, the temperature field within the specimen was predicted by considering thermal conduction inside the substrate/coating system, as well as thermal convection and radiation effects on the free surfaces of the sample. The specimen deformation and the stress status were then calculated by considering the transient temperature at each node as a thermal load. The simulated results indicate that quenching stresses dominate final residual stresses in the deposited coating: the final residual stresses are thus tensile within the coating. The simulated temperature variation and final deflection of the specimen agreed well with the corresponding measurements. It was also found that application of a low cooling rate results in lower residual stresses within the deposited coating. [ABSTRACT FROM AUTHOR]

A bedding plane effect occurs when hydraulic fractures encounter the bedding plane. True triaxial hydraulic fracturing experiments were conducted with test blocks containing bedding planes. The effects of bedding plane properties and stress state on fracture propagation were analyzed. When hydraulic fracture encounters the bedding plane in sedimentary stratum, it usually propagates along the bedding plane at first. When the hydraulic pressure increases to a critical value in the direction of main hydraulic fracture, the main hydraulic fracture continues propagating along the original direction. The length of the long axial of the hydraulic fracture propagating along the bedding plane is greater than the length of the main hydraulic fracture before penetrating the bedding plane, and both of them are greater than the length of the main hydraulic fracture after penetrating the bedding plane. Three-dimensional propagation models were established. Three propagation forms of hydraulic fractures existed when encountering bedding planes: (1) propagation along the bedding plane; (2) initial propagation along the bedding plane followed by penetration of the bedding plane and propagation along the principal direction; and (3) direct penetration of the bedding plane and propagation along the principal direction. [ABSTRACT FROM AUTHOR]

High-performance β-Ga 2 O 3 -based Schottky barrier diodes (SBDs) and metal-semiconductor field-effect transistors (MESFETs) are fabricated on a non-delta-doped high doping level (>1018 cm−3) epitaxial wafer. Their electrical properties and stabilities after annealing at 200–400 °C are investigated. The ON/OFF ratios for all the SBDs are over 108. The ideality factors and Schottky barrier heights for the Au/β-Ga 2 O 3 SBDs with different annealing temperatures range from 1.5 to 2.5 and from 0.8 eV to 1.0 eV, respectively. There are obvious pinch-off and saturation characteristics for the β-Ga 2 O 3 MESFETs. The maximum drain current (I D, max) for the as-fabricated β-Ga 2 O 3 MESFET is 46.8 mA/mm at anode voltage of 2.0 V. They are much higher than the previously reported values of non-delta-doped and nanobelt β-Ga 2 O 3 MESFETs. Threshold voltages for the β-Ga 2 O 3 MESFETs shift to the negative direction with the increase of annealing temperature. This study is meaningful to push forward the development of β-Ga 2 O 3 -based electronic devices for practical applications. • High-performance β-Ga 2 O 3 -based Schottky diodes and metal-semiconductor field-effect transistors (MESFETs) are fabricated on a non-delta-doped high doping level (>1018 cm−3) epitaxial wafer. • Maximum drain current (I D, max) for the as-fabricated β-Ga 2 O 3 MESFET is 46.8 mA/mm at gate voltage of 2.0 V. They are much higher than the previously reported values of non-delta-doped and nanobelt β-Ga 2 O 3 MESFETs. [ABSTRACT FROM AUTHOR]

Plant litter quality considerably affects C accrual in soil organic matter (SOM). However, the chemical traits of litter that influence C distribution in SOM fractions, such as particulate organic matter (POM) and mineral-associated organic matter (MAOM), are not fully understood. Thus, we conducted a 150-day incubation experiment with litter addition (poplar leaves, roots, grasses grown under the canopy, and a mixture of these three litter types). We analyzed the organic C concentration in the POM and MAOM fractions and the stoichiometric ratios (C:N:P) of the soil and microbial biomass 50, 100, and 150 days after the initial litter addition. Microbial residue C (amino sugar biomarkers) in SOM fractions was registered at the end of decomposition. High-quality litter (i.e., leaf) increased MAOM-C accrual, and low-quality litter (i.e., root and grass) contributed more to POM-C accrual. The mixed litter addition accumulated more C in the SOM via high POM-C levels compared to single litter input, likely resulting from an antagonistic effect caused by different litter trait dissimilarity. Moreover, POM-C dynamics were dominated by litter chemical traits during litter decomposition, and MAOM-C was controlled mainly by microbial and soil stoichiometry. Furthermore, the contribution of microbial residue C to SOM (especially POM-C) was lower in the mixed litter than in the single litter. These findings highlight the direct or indirect impacts of litter types on the C dynamics of POM and MAOM, and demonstrate that litter diversity is conducive to C accumulation in SOM. [ABSTRACT FROM AUTHOR]

Three-dimensional simulation model was developed to simulate the thermal and mechanical behaviors of NiCrBSi coatings during laser post-remelting. The post-remelting process of plasma sprayed coatings was performed by a pulsed laser with Gaussian distribution. A numerical model allowing predicting single-pass laser remelting of a thick coating was implemented to investigate the dimensions of the molten pool as a function of processing parameters. The computed results were then validated by the comparison with the corresponding experimental ones. In addition, the thermomechanical model consisting of a beam sample with a length of 80 mm was implemented to evaluate the evolution of the specimen deformation, and residual stress distribution during laser post-remelting. In the case of a NiCrBSi coating elaborated on a stainless steel substrate (316 L), the results indicate that residual stresses within the remelted coating are tensile, while that within the unremelted region of the coating alongside the remelted track are compressive. Finally, the effects of the efficiency of the cooling device on the residual stress distribution were investigated. [ABSTRACT FROM AUTHOR]

The crack susceptibility map of a ternary Al alloy system provides useful information about which alloy compositions are most susceptible to cracking and thus should be avoided by using a filler metal with a significantly different composition. In the present study the crack susceptibility maps of ternary Al alloy systems were calculated based on the maximum | dT/d(f S ) 1/2 | as an index for the crack susceptibility, where T is temperature and f S fraction solid. Due to the complexity associated with ternary alloy solidification, commercial thermodynamic software Pandat and Al database PanAluminum, instead of analytical equations, were used to calculate f S as a function of T and hence the maximum | dT/d(f S ) 1/2 | for ternary Al-Mg-Si, Al-Cu-Mg and Al-Cu-Si alloy systems. A crack susceptibility map covering 121 alloy compositions was constructed for each of the three ternary alloy systems at each of the following three levels of back diffusion: no back diffusion, back diffusion under a 100 °C/s cooling rate, and back diffusion under 20° C/s. The location of the region of high crack susceptibility, which is the most important part of the map, was shown in each of the nine calculated maps. These locations were compared with those observed in crack susceptibility tests by previous investigators. With back diffusion considered, either under 20 or 100 °C/s, the agreement between the calculated and observed maps was good especially for Al-Mg-Si and Al-Cu-Mg. Thus, the maximum | dT/d(f S ) 1/2 | can be used as a crack susceptibility index to construct crack susceptibility maps for ternary Al alloys and to evaluate the effect of back diffusion on their crack susceptibility. [ABSTRACT FROM AUTHOR]

In this study, 8 wt.% yttria-stabilized zirconia powder was deposited on the substrates by atmospheric plasma spray. The coatings were post-treated by laser glazing under different parameters in order to densify them. The characterization of the laser molten pools under different laser treatment conditions was studied. Preheating processes were also employed. Scanning electron microscopy observations of the surface and cross section of as-sprayed and laser-glazed coatings were carried out to investigate the influence of laser glazing on the microstructure on laser-glazed coatings. The results show that preheating processes improve the coating in terms of deepening the laser-glazed layer, reducing the number of vertical cracks and surface density of cracks and widening the molten pool. Finally, the influences of linear energy density on the characterization of the glazed layer are discussed. [ABSTRACT FROM AUTHOR]

Al-Mg alloys, despite their wide freezing temperature range ΔT f , can have good resistance to cracking during solidification. To help understand why, the mushy zone of 5086 Al (∼Al-4.0 Mg) was quenched during arc welding and the cooling curve measured to locate the beginning of the original mushy zone (liquidus temperature T L ) and the end (eutectic temperature T E ). Since little eutectic was visible just slightly behind the beginning of the quenched mushy zone, little liquid was here in the original mushy zone, i.e., solidification already ended well above T E . Since no dendrites were visible, either, and since the highest Mg content measured was well below the maximum solubility in solid Al, C SM (17.5 wt% Mg), microsegregation was very mild here in the original mushy zone. These results suggest significant Mg back diffusion occurred during solidification (because of very high C SM ), causing: 1. fraction solid f S to increase much faster with decreasing temperature T , 2. ΔT f to narrow down, and 3. dendritic grains to bond together extensively ( f S ≈ 1) to resist intergranular cracking earlier (well above T E ). Since | d(f S )/dT | increased, | dT/d(f S ) 1/2 | decreased to decrease the crack susceptibility index, i.e., the maximum | dT/d(f S ) 1/2 |. All these changes reduce the crack susceptibility. For comparison, 2014 Al (∼Al-4.4Cu) was also quenched during arc welding. At the end of the quenched 2014 Al mushy zone, continuous eutectic, dendrites and microsegregation were all very clear. Thus, solidification ended at T E and thin liquid films still separated grains at the end of the original mushy zone to allow intergranular cracking. Calculated T-(f S ) 1/2 curves showed the index is reduced significantly by back diffusion in Al-4.0 Mg (∼5086 Al) but not in Al-4.4Cu (∼2014 Al). [ABSTRACT FROM AUTHOR]

CoMoCrSi coatings were manufactured on a steel substrate by atmospheric plasma spraying (APS), followed by a three-hour heat treatment at a temperature of 800 °C and 1000 °C, respectively. Prior to the ultrasonic test of the cavitation erosion, coating cross-sections were observed by scanning electron microscopy (SEM) and analyzed by X-ray diffraction (XRD). 3D profiles were employed to investigate the erosion mechanism on both pristine and eroded surfaces. As a result, it is shown that the heat treatment can significantly reduce the mean erosion depth of the CoMoCrSi coatings and the cavitation damages mainly consist of the removal of the splashes with weak adhesion during plasma spray and the delamination of fragments from bubble collapses. [ABSTRACT FROM AUTHOR]

We propose a novel continuous-flow microfluidic particle concentrator with a specified focusing-particle number ratio (FR) at different channel outlets using induced-charge electroosmosis (ICEO). The particle-focusing region contains two floating electrodes of asymmetric widths L2 and L1 in the gap between a driving electrode pair, all of which are fabricated in parallel in the main channel. Applying an AC voltage over the driving electrodes, an ICEO flow with two vortexes can be induced over each of the two floating electrodes, and the actuation range of the ICEO vortex is proportional to the respective electrode size. We establish a preliminary physical model for the value of FR: at a moderate voltage and frequency range, FR approaches L2/L1 due to the scaled ICEO actuation range; by further modifying the voltage or frequency, FR is freely adjustable because of the variation in ICEO velocity. Furthermore, by connecting multiple focusing regions in series, i.e., high FR = (L2/L1)n can be conveniently generated in an n-stage flow focusing device. Our results provide a promising method for yielding transverse concentration gradients of particles useful in pre-processing before analysis. [ABSTRACT FROM AUTHOR]

Surface energy plays a key role in the physicochemical interactions of material surfaces, and it is closely related to the unique properties and numerous surface functionalization possibilities of gold nanoparticles. Herein, we have reported an atomic force microscopy based technique to measure the surface energies of different materials in the peakforce quantitative nanomechanical mapping mode. Our study on gold nanoparticles focuses on the particles with diameters ranging from 2 to 14 nm. The experimental results indicate a clear size-dependent behavior in the surface energy of gold nanoparticles when the size is smaller than 5 nm, and the smallest gold nanoparticle displays a threefold higher surface energy compared to bulk gold. Therefore, our experimental results provide essential evidence that can lead to a better understanding of the size-property relationships allowing for process design in gold nanoparticles. [ABSTRACT FROM AUTHOR]

Cracking can occur during solidification in welding and casting. The present study attempted to deal with some fundamental questions regarding the susceptibility to cracking during solidification. How does the phase diagram affect the crack susceptibility? Can back diffusion occur in welding? How is the dihedral angle related to bridging between grains? To help answer the questions, the maximum | dT / d ( f S ) 1 / 2 | ( T is temperature and f S fraction solid) was calculated, whose validity as the crack susceptibility index was verified recently. To deal with curved solidus and liquidus lines (i.e., variable equilibrium segregation coefficient k ), f S was calculated as a function of T by numerical integration instead of by a simple analytical equation for constant k . Based on the secondary dendrite arm spacing λ 2 in common Al arc welds and the λ 2 − t f data of Al alloys ( t f is local solidification time), it was shown that back diffusion can occur in Al arc welding. Binary Al alloy systems were investigated over wide ranges of the eutectic temperature T E (229–548 °C) and k (about 0–0.87 at T E ). It was shown that with a very low T E the crack susceptibility can still be relatively low if k is very high at T E to increase the effect of back diffusion on crack susceptibility reduction, consistent with the lower crack susceptibility of Al-Mg and even Al-Zn than Al-Cu. With both a very low T E and a very low k at T E , however, the crack susceptibility can be very high, consistent with the severe crack susceptibility of Al-Sn. The effect of the curvature of the liquidus and solidus lines on the crack susceptibility was shown. A possible link between the dihedral angle and bridging between grains was also shown. [ABSTRACT FROM AUTHOR]

A 3D multi-layer model was established to simulate the hybrid plasma spray process with in-situ laser remelting. Effective properties of as-sprayed and remelted NiCrBSi coatings versus temperature were used during the thermal and mechanical analysis. Considering the surface roughness of plasma sprayed NiCrBSi coatings, an absorption coefficient of 0.5 was estimated from the comparison of the predicted and measured remelted thickness. The heat accumulation during the deposition process of multiple layers affects the temperature level, as well as the stress magnitude. The predicted results also indicate that the longitudinal component of the residual stresses is the highest. During final cooling, the stresses generated in the remelted coating are more sensitive to the variation of the elastic modulus rather than the mismatch of the expansion coefficient between the coating and the substrate, which thus induces tensile stresses within the remelted coating. Finally, the influence of the cooling rate was limited while the substrate preheating seems a good method to decrease the stress level within the remelted coating. [ABSTRACT FROM AUTHOR]

Cracking during solidification is a serious defect in welds and castings. A criterion for cracking that, unlike previous criteria/models, considers the grain boundary (where cracking occurs) was proposed recently. Based on this criterion, the maximum | dT / d ( f S ) 1/2 | ( T is temperature and f S fraction solid) of an alloy was proposed as an index for its crack susceptibility and the validity of the index was verified. The present study used the index to demonstrate the important effect of diffusion on the crack susceptibility and explained the surprisingly low crack susceptibility of Al–Mg alloys in welding. This was done by deriving closed-form equations to calculate the curves of crack susceptibility (the index) vs. solute content for binary Al–Si, Al–Cu and Al–Mg alloys. The curves were Λ-shaped, consistent with those observed in the crack susceptibility tests of binary alloy systems. It was shown that diffusion from liquid into Al-rich dendrites reduces the peak of the Λ-curve and shifts it to higher solute contents. The very high Mg solubility in solid Al, 17.5 wt% according to the Al–Mg phase diagram, makes Mg diffusion unusually significant, thus explaining the good weldability of Al–Mg alloys. The present study indicates the need to consider diffusion when comparing Λ-curves of different alloy systems, where the phase diagram can affect diffusion, or different tests of the same alloy system, where the cooling rate during welding or casting can affect diffusion. [ABSTRACT FROM AUTHOR]

A HfO 2 /Al 2 O 3 multilayer has been deposited by an atomic layer deposition (ALD) technique on a hydrogenated-diamond (H-diamond) epitaxial layer. Electrical properties of the ALD-HfO 2 /Al 2 O 3 /H-diamond metal-insulator-semiconductor (MIS) diode have been investigated to compare with those of the single ALD-Al 2 O 3 /H-diamond and ALD-HfO 2 /H-diamond MIS diodes. The leakage current density for the ALD-HfO 2 /Al 2 O 3 /H-diamond MIS diode is smaller than 3.8 × 10 − 8 A·cm − 2 with electric field ranging from − 1.6 to 1.0 MV·cm − 1 . The dielectric constant for the ALD-HfO 2 /Al 2 O 3 multilayer is larger than that for the single ALD-Al 2 O 3 . The fixed charge density in the ALD-HfO 2 /Al 2 O 3 /H-diamond structure is much lower than that in the single ALD-HfO 2 /H-diamond structure. The electrical properties of the ALD-HfO 2 /Al 2 O 3 /H-diamond MIS field effect transistor have also been investigated. The source–drain current and extrinsic transconductance maxima are − 42.1 mA·mm − 1 and 6.2 ± 0.1 mS·mm − 1 , respectively. The effective mobility for the H-diamond channel layer has been determined to be 38.2 ± 0.5 cm 2 ·V − 1 ·s − 1 . [ABSTRACT FROM AUTHOR]

As the mathematical model has been developed in part I, the simulation results of the transport phenomena and solidification cracking in laser spot bead-on-plate welding of AA6063-T6 aluminum alloy and the experimental validation are presented in this paper. Modeling results showed that the solute concentration in the solidified region continuously increases during the solidification process. As the temperature is lower than the coherent temperature (i.e., the temperature at which the coherent mushy zone is just formed), the strains accumulated in the coherent mushy zone increase with the increasing solid fraction. The amount of strain in the mushy zone is primarily determined by the life (i.e., time span) of the coherent mushy zone, which is determined by the solidification range and solidification time. The increased solidification range and consequently solidification time extend the life of the coherent mushy zone, which increases the amount of strain and thus increases the likelihood of solidification cracking. The modeling results are in agreement with the experimental results. Both the experimental and modeling results exhibited that solidification cracking is prone to occurring near the top surface and middle part of the weld bead and an increase of laser power leads to the higher cracking susceptibility. [ABSTRACT FROM AUTHOR]

In this study, a transient unified model including simulation of the temperature, velocity, solute (MgSi) concentration and stress fields, free surface, and laser-induced plasma, has been developed to predict the transport phenomena and solidification cracking susceptibility during laser spot bead-on-plate welding of aluminum alloy. The model consists of the modeling of heat, momentum and mass transports in the metal and plasma zones, thermomechanical modeling, and evaluation of solidification cracking. The full set of mathematical equations and numerical methods are presented. The main challenges and the corresponding solutions for the modeling are discussed. In this model, the lever-rule based on the phase diagram was used to deal with the macroscale segregation at the solid-liquid interface, while the solute transfer due to the diffusion and convection were calculated by the conservation equations for transport phenomena. The solute redistribution in the weldment is coupled with the changes of liquidus and solidus temperatures of the material. The total strain consists of the elastic, viscoplastic, and thermal parts that are coupled with the calculated temperature, velocity, and solute in the weldment. The criterion for the weld solidification cracking was established based on the strain theory, in which the cracking initiates only when the strain exceeds the threshold strain in the brittle temperature range (btr). [ABSTRACT FROM AUTHOR]

Ta2O5 films have been deposited on hydrogen-terminated diamond (H-diamond) by a radio-frequency sputter-deposition technique at room temperature. Electronic band structure of Ta2O5/H-diamond heterojunction has been investigated by X-ray photoelectron spectroscopy. Based on the binding energies of core-levels and valence band maximum values, valence band offset has been found to be 1.5±0.2eV for the Ta2O5/H-diamond heterointerface. It shows a type-II band configuration with conduction band offset of 2.4±0.2eV. The large ΔEV value makes the Ta2O5/H-diamond heterojunction probably suitable for the application of high power and high frequency field effect transistors. [ABSTRACT FROM AUTHOR]

In this work, experimental and numerical approaches are performed to explore the influence of scanning strategies on the microstructure, crystallographic texture as well as the mechanical behavior of Ti-6Al-4V alloy manufactured by Laser Powder Bed Fusion (LPBF). In-situ monitored data of the energy intensity show that different scanning strategies result in variations of energy intensity distribution. The characterization of the microstructure and crystallographic texture reveals that the sample with hexagon scan pattern displays the structure with columnar primary β phase, while the specimens with chessboard scan exhibit equiaxial-like morphology. EBSD and TEM results provide evidence of the appearance of residual β nanoparticles. A finite element model is developed to further explain the phase transformation during LPBF and the formation mechanism of residual β particles. The numerical results indicate that the appearance of the residual β phase is attributed to the preheating/reheating effect by the adjacent tracks and successive layers, and the final phase composition of the LPBF-built Ti-6Al-4V alloy combines the α′, α, and β phases. Findings in the present paper show that various scanning strategies lead to a clear diversification in the microstructure, crystallographic texture, and phase composition of LPBF-built samples, which opens a route towards the tailoring of mechanical properties and isotropic behaviors in additive manufacturing. [ABSTRACT FROM AUTHOR]

Abstract: To accurately evaluate the danger from rock bursts during coal mining, uniaxial compression tests of composed coal rock at different loading rates were carried out. The effect of the rate and path of loading and unloading on the mechanical properties of the composed coal rock has been analyzed. The overall elastic modulus, peak strength, and residual strength of the composed coal rock lie among that of roof, coal, and floor. The stress–strain characteristics of the composed coal rock depended on the part of the system with the smallest stiffness. The stress–strain curve during the post-peak failure stage was smoother than that of a single rock specimen on the whole. The stiffness difference markedly influenced the failure form and propensity to rockburst of the composed coal rock. With an increase of loading rate, the strain increment of the composed coal rock in the elastic phase, the plastic phase, and the failure phase gradually increased, and the strain at the peak point rose linearly. Faster strain rates made the curves smoother with smaller slopes. In comparison to monotonic loading, all the strain increments of the composed coal rock in the elastic phase, the plastic phase, and the peak strength point of cyclic loading were smaller; both the elastic modulus and peak strength were greater. Fast loading enhanced the capacity of the composed coal rock to convert outside energy to its own elastic energy. With an increase of loading rate, both the post-peak secant modulus and the strain softening modulus of the composed coal rock gradually decreased as negative logarithmic curves on the whole. The dynamic failure time gradually decreased as a hyperbolic curve, with enhanced brittleness. Consequently, composed coal rock and the rapid loading and unloading effect induced by mining should be considered for evaluating rockburst propensity. [Copyright &y& Elsevier]

Background: Estrogen receptor (ER) positive human epidermal growth factor receptor 2 (HER2) negative breast cancer (ER+/HER2−BC) and triple-negative breast cancer (TNBC) are two distinct breast cancer molecular subtypes, especially in tumor immune microenvironment (TIME). The TIME of TNBC is considered to be more inflammatory than that of ER+/HER2−BC. Natural killer (NK) cells are innate lymphocytes that play an important role of tumor eradication in TME. However, studies focusing on the different cell states of NK cells in breast cancer subtypes are still inadequate. Methods: In this study, single-cell mRNA sequencing (scRNA-seq) and bulk mRNA sequencing data from ER+/HER2−BC and TNBC were analyzed. Key regulator of NK cell suppression in ER+/HER2−BC, S100A9, was quantified by qPCR and ELISA in MCF-7, T47D, MDA-MB-468 and MDA-MB-231 cell lines. The prognosis predictability of S100A9 and NK activation markers was evaluated by Kaplan–Meier analyses using TCGA-BRAC data. The phenotype changes of NK cells in ER+/HER2−BC after overexpressing S100A9 in cancer cells were evaluated by the production levels of IFN-gamma, perforin and granzyme B and cytotoxicity assay. Results: By analyzing scRNA-seq data, we found that multiple genes involved in cellular stress response were upregulated in ER+/HER2−BC compared with TNBC. Moreover, TLR regulation pathway was significantly enriched using differentially expressed genes (DEGs) from comparing the transcriptome data of ER+/HER2−BC and TNBC cancer cells, and NK cell infiltration high/low groups. Among the DEGs, S100A9 was identified as a key regulator. Patients with higher expression levels of S100A9 and NK cell activation markers had better overall survival. Furthermore, we proved that overexpression of S100A9 in ER+/HER2-cells could improve cocultured NK cell function. Conclusion: In conclusion, the study we presented demonstrated that NK cells in ER+/HER2−BC were hypofunctional, and S100A9 was an important regulator of NK cell function in ER+BC. Our work contributes to elucidate the regulatory networks between cancer cells and NK cells and may provide theoretical basis for novel drug development. [ABSTRACT FROM AUTHOR]

Parecoxib, a well‐recognized nonsteroidal anti‐inflammatory drug, has been reported to possess anticancer properties in various tumor types. In this work, we aimed to investigate the potential anticancer effects of parecoxib on hepatocellular carcinoma (HCC) cells. To assess the impact of parecoxib on HCC cell proliferation, we employed Cell Counting Kit‐8, colony formation, and 5‐ethynyl‐2′‐deoxyuridine assays. Hoechst/propidium iodide (PI) double staining and flow cytometry were performed to evaluate apoptosis and cell cycle analysis. Wound healing and transwell assays were utilized to assess cell migration and invasion. Tube formation assay was employed to analyze angiogenesis. Protein levels were determined using western blotting, and mRNA expression levels were assessed using quantitative real‐time polymerase chain reaction (PCR). A xenograft mouse model was used to confirm the antitumor effects of parecoxib on HCC tumors in vivo. Our data demonstrated that parecoxib effectively inhibited the proliferation of HCC cells in a dose‐ and time‐dependent manner. In addition, parecoxib induced cell cycle arrest in the G2 phase and promoted apoptosis. Moreover, parecoxib hindered tumor migration and invasion by impeding the epithelial–mesenchymal transition process. Further investigation showed that parecoxib could significantly suppress angiogenesis through the inhibition of extracellular signal‐regulated kinase (ERK)–vascular endothelial growth factor (VEGF) axis. Notably, treatment with the ERK activator phorbol myristate acetate upregulated the expression of matrix metalloproteinase (MMP)‐2, MMP‐9, and VEGF and reversed the function of parecoxib in HCC cells. Besides, parecoxib displayed its antitumor efficacy in vivo. Collectively, our results suggest that parecoxib ameliorates HCC progression by regulating proliferation, cell cycle, apoptosis, migration, invasion, and angiogenesis through the ERK–VEGF/MMPs signaling pathway. [ABSTRACT FROM AUTHOR]

• Frustum tube system enhances both conduction and convection. • Geometry modification significantly affects heat transfer in pure PCM. • Combination of frustum tube and metal foam further improves melting performance. • The frustum tube system outperforms the conical shell one. In this study, seven vertical shell-tube latent heat storage (LHS) systems are built to explore the effect of geometry on the melting and solidification behavior of phase change material (PCM). The performances of these systems using pure PCM (paraffin RT82) and composite PCM (paraffin RT82 embedded in copper foam) are investigated. Two-dimensional numerical model based on the enthalpy-porosity method and two-temperature energy equations is developed and verified with the experimental data. The solid-liquid interface, isotherms, time histories of liquid fraction and stored energy are used to evaluate the thermal performance. Results show that the conical shell system enhances natural convection compared with the cylinder system, whereas the frustum tube system enhances both convection and conduction. Geometry modification has little effect on the thermal performance of composite metal foam/PCM. Compared with the cylinder LHS system, the complete melting time with geometry modification is reduced by at least 9.2% for pure PCM, and less than 5.9% for composite metal foam/PCM. Moreover, it is also found that the frustum tube system outperforms the conical shell system in both melting and solidification, regardless of metal foam and HTF material. [ABSTRACT FROM AUTHOR]

A strong and hard hanging roof causes high underground stress in underground mines, leading to rock burst, coal and gas outburst, or large deformations in roadways. To address these problems, hydraulic fracturing can form hydraulic cracks in strong hanging roofs and promote fractures in the hanging-roof. However, it is difficult to ensure that hydraulic cracks propagate vertically through rock strata. Therefore, a novel method has been proposed that uses hydraulic fracturing to generate vertical fractures in hard hanging roofs for-roof cutting and stress relief. The method exploits the additional horizontal tensile stress produced by the bending deformation of the roof so that the fracturing point occurs in a desirable tensile-stress area, and therefore to promote the vertical expansion of hydraulic cracks that cut off the rock strata. In this paper, the position of the maximum additional horizontal tensile stress is taken to be the reasonable fracturing position given by a mechanical model. Solving this model indicates that a shorter hanging roof equates to a thicker hanging roof, a larger elastic modulus, a smaller elastic cushion coefficient, and a fracturing position that is deeper in the coal wall. The various factors that affect the reasonable fracturing position may be ordered in terms of their impact as follows: hanging-roof length > hanging-roof elastic modulus > hanging-roof thickness > elastic cushion coefficient > horizontal stress. The proposed method has been applied to roadway 5103 of the Majiliang Coal Mine of Datong Coal Mine Group Co., Ltd. The results show that hydraulic fracturing forms vertical hydraulic cracks at the point of maximum additional horizontal tensile stress, which can effectively control the deformation in the surrounding rock. The fracturing position calculated by using this model is reasonable and reliable and can be used to guide the on-site construction. [ABSTRACT FROM AUTHOR]

In this work, the tensile behavior and microhardness of 316L stainless steel fabricated by selective laser melting under different process parameters were investigated. The ultimate tensile strength decreased slightly with increasing energy input, while the opposite tendency was observed for the elongation to failure. Microstructure characterizations were performed to relate the pore morphology, melting pool geometry, solidification cell structure, and grain sizes to the mechanical performance of as-built samples. Fine grains with high fraction of low-angle grain boundaries and fine cellular structures with nano-inclusions are observed in the sample fabricated with a high scanning speed (1000 mm/s). As a result, the sample shows high ultimate tensile strength of up to 707 MPa, while maintaining a total elongation of 30%. The sample fabricated with a low scanning speed (800 mm/s) shows high ductility with total elongation to failure of 55%. The improved ductility is mainly attributed to the elimination of residual pores and melting pool boundaries, which result in brittle features in the as-built samples. The results indicate that selective laser melting may act as a physical metallurgy method to modify the microstructure, and thus improve the mechanical performance of metallic materials. Unlabelled Image • The scanning speed altered melting pool boundaries, residual pores, solidification cells, nano-inclusions and grain sizes. • High ultimate tensile strength was attributed to fine cellular structures and fine grains with low-angle grain boundaries. • Low scanning speed resulted in an enhanced ductility due to the minimization of residual defects and melting pool boundaries. [ABSTRACT FROM AUTHOR]

Improving the ductility of manufactured Ti-based alloys by selective laser melting (SLM) while still maintaining the high mechanical strength is one of the major challenges in additive manufacturing. In this work, a systematic investigation on the process parameters for achieving such a material is performed. By employing the optimal parameters during SLM, the fabrication of strong and ductile Ti6Al4V alloys was achieved. The ultimate tensile strength of SLM-built Ti6Al4V alloy was measured as 1170 MPa, while the elongation to failure remained over 10%. Through analysis of the microstructure and mechanical properties of the SLM-built Ti6Al4V alloy, it was found that the process parameters play an essential role in the tensile behavior, in particular the ductility of SLM-built Ti alloy. The considerable enhancement of the mechanical properties in our work is mainly attributed to the limitation of martensite formation and the minimization of pores. [ABSTRACT FROM AUTHOR]

The front cover image is based on the Research Article Proposition of a critical design direct normal irradiance for solar thermal power plant, by Jiangwei Liu et al., https://doi.org/10.1002/er.4138. [ABSTRACT FROM AUTHOR]