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The toolpath based on the support tool adjustment to the local normal of the master tool has a substantial effect on the final component quality in double-sided incremental forming (DSIF). Two novel toolpaths based on two new support tool positions to the master tool were investigated for their effects on forming quality. These toolpaths were based on adjusting and maintaining the support tool at a specific gap (ϕ = 7.75° and 15.5°) from the local normal of the master tools in the meridional orientation in the direction of the already formed part without pneumatic-assisted support tool. The adjustment of the support tool at ϕ = 7.75° deforms the sheet based on the sheet compression and reverse bending, whereas support tool adjustment at ϕ = 15.5° deforms the sheet based on reverse bending. The two new toolpaths were compared to each other and to a normal DSIF toolpath based on experimental results for geometric precision, surface finish, processing time, and component sheet thickness variation. Simulation results for these toolpaths were also evaluated to support the experimental results and understand the process mechanism. The three main challenges posed by the DSIF process, geometric precision, sheet thickness distribution, and surface roughness, were improved up to 30%, 1.07%, and 21.81%, respectively, using the new toolpaths without compromising the forming time. The combined reverse bending and compression improved the forming quality effectively compared to only reverse bending or compression. These toolpath benefits are the no additional requirements for additional equipment, reducing capital and operational cost. [ABSTRACT FROM AUTHOR]

Humans have had profound and environmentally changing impacts on land cover, and China has many examples of this. It has been recognised for some time that middle to late Holocene forests in China have undergone changes that are best described as due to human impacts. Hence the Holocene has seen sometimes gradual and sometimes abrupt changes from forest dynamics driven by natural forces to those dominated by human impacts. This leads to a conclusion that it is often difficult to disentangle natural and anthropogenic controls on forest composition. In many cases records show minor changes in the early Holocene giving way to intense changes as agriculture expanded. The two earliest centres of extensive forest changes from 6 to 5 kyr BP were in the middle to lower Yellow and lower Yangtze valleys, where millet and rice agriculture developed. Major forest clearing was later in other areas, including the Pearl River valley, Northeast China and Yunnan. Forest clearing for agriculture was widespread in eastern China by 2 kyr BP. Where data is available it seems that initial clearing took place in valleys adjacent to rivers, presumably because these were the preferred living places for early farmers. Then gradually spread to nearby slopes. New approaches and technologies were needed to achieve this. The records show that north east China, north of the Liao River, and the mountains of central China were amongst the last places to record forest clearing, in some cases just within the last few hundred years, or not at all. [ABSTRACT FROM AUTHOR]

In order to enhance the limited information on elevated temperature stability of MAX phase materials, Ti 2 AlN MAX phase composites were fabricated in a two-step procedure and subsequently tested regarding their oxidation and creep behavior. Furthermore, commentary testing on material enhanced with different amount of Al 2 O 3 fibers was performed. The compressive creep was investigated in the temperature range of 900–1200 °C under stresses ranging from 20 to 100 MPa, with a loading direction parallel and perpendicular to the compression direction during sintering. The oxidation behavior was characterized, demonstrating excellent oxidation resistance of the samples up to 1200 °C. Supported by microstructural investigations, the impact of the texturing of the matrix grains, the content and the orientation of Al 2 O 3 fibers, as well as that of the interfaces between matrix grains and the Al 2 O 3 fibers were investigated. De-cohesion and cracks formed at the triple junctions of the MAX phase grains indicate grain boundary sliding as predominant creep mechanism for the composites. [ABSTRACT FROM AUTHOR]

Large-scale hydrogen underground storage is widely considered as an important solution for energy transition to mitigate global warming, however, our understanding on the various chemical and physical processes leading to H 2 loss during geo-storage remains largely unknown. We conducted adsorption isotherms measurements of H 2 , CH 4 and CO 2 on Cretaceous Cameo coal at 35, 50 and 65 °C, to explore adsorption mechanisms of H 2 and deciphering the effect of cushion gas (e.g., CH 4 , CO 2) on H 2 loss in the subsurface. The adsorbed amounts of H 2 are just 12% and 6% of CH 4 and CO 2 at temperature of 35 °C and pressure of 2.3 MPa, respectively, and H 2 adsorption behavior on Cameo coal can be described well by Langmuir monolayer theory. The extremely high Langmuir pressures (35–49 MPa) for H 2 indicate very weak affinity with coal, compared to CH 4 and CO 2. Differences of Langmuir adsorption capacities suggest that the gas adsorption of H 2 and CH 4 are mainly by physical interactions while both physical and chemical bonding with coal structures occurs for CO 2. The affinity with solid materials for the three gases can be quantitatively evaluated by the heat of adsorption, which was determined to be ∼9.2 kJ/mol for H 2. Extrapolation of our experimental results to natural coal seams indicates that H 2 presents much smaller adsorption amounts at depth up to 2000 m, corresponding to temperatures lower than 65 °C and pressure less than 30 MPa, geological conditions that are suitable for hydrogen underground storage. This study confirms that the injection of CH 4 or CO 2 as cushion gas can largely reduce the H 2 loss by adsorption in the subsurface. Empirical calculation suggests H 2 adsorption will be insignificant with chemical composition of CH 4 above 8% or CO 2 above 2% at the storage sites (e.g., abandoned mines, depleted coal seams). Our study lays a foundation on the understanding of the risk of H 2 loss in large-scale hydrogen underground storage. • Adsorbed amounts of H 2 are much smaller than CH 4 and CO 2. • Weak affinity of H 2 with coals is quantitatively evaluated. • H 2 loss by adsorption during geological storage can be significantly reduced by the injection of CH 4 or CO 2 as cushion gas. [ABSTRACT FROM AUTHOR]

Position-specific (PS) carbon isotope compositions of light hydrocarbons such as propane and butane isomers (n-butane and i-butane) can provide a wealth of information on the history of natural gases in the subsurface reservoirs and other environments. For PS carbon isotope analysis of butane isomers, we have established a GC-pyrolysis-GC-isotope ratio mass spectrometry method with demonstrated accuracy. With this method, we analyzed PS δ13C values of butane isomers generated from the systematic laboratory pyrolysis experiments of three different kerogen types (I, II, and III) at temperatures of 310–430 °C with corresponding thermal maturity (Easy %R o) ranging from 0.7 to 3.3. The observed evolution in the abundances of butane isomers can be interpreted and semi-quantitatively modeled based on the abundances of different C C bonds within the kerogens at low maturity and thermal degradation of butane isomers at high maturity. The δ13C values at the central sites of both nC 4 and iC 4 were heavier than those at the terminal positions, similar to our previous observations of propane. Their isotopic evolution with the maturity were controlled largely by kinetic isotope effects associated with breaking of different C C bonds during the generation and degradation of butane isomers. Kinetic Monte Carlo (kMC) simulations of n-butane generated from thermal cracking of model kerogens (I, II, and III) and an oil with a series of reactions (homolytic cleavage, β-scission, radical isomerization, H-abstraction, and termination by radical recombination) provided generally consistent results with the experimental observations, although the difference in PS δ13C values between the central and terminal positions are somewhat overestimated. On the other hand, the kMC simulation with homolytic cleavage and capping reactions alone produced significant deviations from the experimental results. Re-assessment of very limited data of PS δ13C values of natural butanes with our experimental and simulation results show that biodegradation significantly increased δ13C values at the central positions, not only of propane, but also of both butane isomers. This study lays a foundation and demonstrates the potential of PS isotope geochemistry of butane isomers to further improve our understanding of the sources, and geochemical and microbial processes of light hydrocarbons in the subsurface and other natural environments. [ABSTRACT FROM AUTHOR]

The binary composite, ZnSnO3 microcubes (ZSO MC) homogeneously parceled in an N-doped carbon nanofiber membrane (ZSO@CNFM), was synthesized via a mild hydrothermal, electrospinning and carbonization process as a flexible lithium-ion battery (LIB) anode material. The unique carbon-coating layer architecture of ZSO@CNFM not only plays a crucial role in alleviating the volume change of ZSO MC during lithium ion insertion/extraction processes, but also constructs a three-dimensional (3D) transport network with the help of interconnected carbon nanofibers (CNFs) to ensure the structural integrity of the material and promote the electrochemical reaction kinetics. Due to its good flexibility characteristics, the as-prepared ZSO@CNFM can be directly adopted as an anode material for LIBs without the use of copper foil, conductive carbon black and any binder. Electrochemical surveying results manifest that the optimal ZSO@CNFM electrode displays excellent cycling stability (582.6 mA h g−1 after 100 lithiation/delithiation cycles at 100 mA g−1), high coulombic efficiency (CE, 99.6% at 100th cycles), and superior rate performance (349.5 mA h g−1 at 2 A g−1). The good electrochemical properties can be ascribed to the synergistic effect of the high theoretical specific capacity of ZSO MC, favourable stability of the carbon substrate, the open structure of ZSO@CNFM and the 3D continuous highly conductive framework for rapid electron/ion transfer. [ABSTRACT FROM AUTHOR]

Due to the excellent properties of Ti (C,N)-based ceramics, such as high hardness, excellent wear resistance, exceptional thermal deformation resistance, and sound chemical stability, they have been widely used in cutting tools or molds. Thus, revealing their tribological behavior against hard materials is of great significance. Some studies have reported the tribological behavior of Ti(C,N)-based cermets and hard cermets, but so far, the effects of Mo2C additions on the frictional properties of Ti(C,N)-based cermets are still unclear. In this study, Ti(C,N)-10WC-1Cr3C2-5Co-10Ni-x Mo2C cermets (x = 4, 6, 8, 10 and 12 wt.%) were sintered using a vacuum hot-pressing furnace. Furthermore, the core–rim morphologies of the sintered samples were observed in SEM images. Then, the wear resistance of the cermets was studied against a Si3N4 ball at a 50 N load using the fretting wear test. Finally, the wear mechanism was characterized using a combination of SEM, EDS and XPS. The experimental results indicated that the wear mechanisms of the cermets were mainly abrasive wear, adhesive wear, and the formation of an oxide film. As the content of Mo2C increased from 4 wt.% to 12 wt.%, the friction coefficient and wear volume had a variation law of first decreasing and then decreasing, and reached minimum values at 6 wt.% and 12 wt.%, and the lowest friction coefficient and wear rate were 0.49 and 0.9 × 10−6 mm3/Nm, respectively. The 6 wt.% Mo2C greatly improved the hardness and fracture toughness of the cermet, while the 12 wt.% Mo2C promoted the formation of an oxide film and protected the friction surface. The cermet with 6 wt.% Mo2C is recommended because it has comprehensive advantages in terms of its mechanical properties, tribological properties, and cost. [ABSTRACT FROM AUTHOR]

Melts and fluids derived from subducting/subducted oceanic lithosphere contribute significantly to mantle compositional heterogeneity. Historically metasomatized lithospheric mantle modified by varying materials, especially volatile-rich slab fluids, has been understood to be crucial for the formation of giant ore deposits, thus providing potential prospective areas for mineral exploration. However, it is not straightforward to identify superimposed effects of slab melts and fluids on the sub-continental lithosphere (SCLM) that has experienced long-lived and/or multiple metasomatism. In this study, we present a novel study using Mg and K isotopes, together with radioactive isotopes on mafic post-collisional alkaline potassic rocks (PARs) with the aim of deciphering varying agents contributing to the heterogeneous metasomatism of the SCLM beneath the southeastern Tibetan Plateau. The PARs, formed at ∼36 Ma, are characterized by high abundances of large ion lithophile elements (LILE) but depleted in high field strength elements (HFSE) with high Rb/Sr ratios, indicating a phlogopite-bearing mantle source. We find that features of light Mg (δ26Mg = −0.52 to −0.25‰) and heavy K (δ41K = −0.56 to +0.08‰) isotopes observed in the PARs are largely inherited from their mantle sources with negligible effects of kinetic fractionation, fractional crystallization and crustal level processes. Our modelling reveals that the notable divergence of Sr–Nd–Pb–Mg–K isotope compositions between PAR suites in different tectonic blocks are best understood as resulting from varying contributions of slab-derived components into the overlying mantle lithosphere, including sediment-derived melts, ocean crust-derived supercritical fluids, and marine carbonates. Particularly, their high Th/U ratios and negative correlations between δ26Mg and δ41K values suggest that slab-derived supercritical fluids can dissolve and transport Mg-rich (dolomitic) carbonate into the mantle wedge. [ABSTRACT FROM AUTHOR]

Through the use of the independently developed Thunderstorm Energetic Radiation Observation System (TEROS), observation experiments of rocket-triggered lightning energetic radiation (RLER) were conducted for the first time at the Field Experiment Base on Lightning Sciences, China Meteorological Administration from May 2021 to July 2021. A total of 17 X-ray bursts were detected during all of the 22 leader/return strokes. In this study, the energy, time, and direction characteristics of X-ray burst and its relationships with the corresponding discharge parameters, such as the return stroke peak current, half-peak width, rise time, and interstroke time interval, as well as the associated physical processes, are analyzed and discussed. Results showed that energetic radiation is ubiquitous in triggered lightning and is closely related to the last downward leader phase before the return stroke. The photon energies were concentrated in tens to hundreds of keV, and the average duration of RLER was approximately 27 µs. Moreover, RLER exhibited directional property inconsistent with a vertical downward beam, which may be related to the development orientation of the lightning leader. The intensity of RLER was positively correlated with the return stroke peak current, indicating that it directly depends on the lightning intensity, but it would be modulated by the lightning channel conditions. The 17 RLER events showed 3 different time distribution patterns, namely, discrete, continuous, and discrete/continuous pulses, of which the discharge parameters were also different. The discrete pulse event had the longest duration, a small half-peak width, and a long interstroke time interval. Furthermore, all of these events occurred during the last several leader/return strokes. The continuous pulse event had a short duration and a small peak current. The discrete/continuous pulse event had a moderate duration and a large half-peak width and peak current. These three distinct time distribution patterns may be determined by different development types of lightning leaders. Our observations support the leader high-field runaway mechanism. [ABSTRACT FROM AUTHOR]

Although great efforts have been devoted to developing lightweight models for age estimation in recent works, the robustness is still unsatisfactory in unconstrained environments. This paper proposes a Group‐aware Contrastive Network (GACN), a robust lightweight model, which extracts discriminative features by leveraging contrastive learning rather than increasing model parameters. Specifically, with a carefully designed contrastive loss function, GACN minimizes intra‐class distances and maximizes inter‐class distances between different age groups in feature space. Thus, faces belonging to the same age group are pulled together, while clusters of faces from different age groups are pushed apart. Unlike existing contrastive learning methods, which are separated from the downstream tasks, GACN integrates contrastive learning into age regression and jointly optimizes them for age representation learning. This allows to achieve robust age estimation using a lightweight network that is 1/662 of the model size of VGGNet. Extensive experiments on IMDB‐WIKI, Morph II, and FG‐NET demonstrate that the proposed method has a significant improvement over the baseline model and performs comparably to existing compact and bulky methods. [ABSTRACT FROM AUTHOR]

Summary: Sorghum germplasm resources were abundant, and their comprehensive utilisation was also more in‐depth. Starch had attracted much attention as the main component in grain, but starch retrogradation limited its better development and utilisation. Therefore, the property changes of sorghum starch retrogradation were studied. The differences in the properties of the four kinds of sorghum starches during retrogradation were mainly due to composition and structure among the varieties. With the increase in retrogradation days, the order of L1 starch was better at 0.994, the retrogradation rate of L13 starch increased by 36.23%, and the recrystallisation degree of H5 starch was 0.064 worse than that of native starch. However, the physicochemical properties of H1 retrograded starch were different from those of the other three. It was shown that the solubility increased to 47.67%, the transparency was 43.36%, and the water‐holding capacity was 91.35%. Retrogradation made that the surface of sorghum starch gel fragments had an orderly scale‐like structure, which did not cause the generation of new groups, reduced the crystalline strength and the energy required for gelatinisation. The crystallisation rate was positively correlated with syneresis, swelling and orderliness, as well as T0, Tp, Tc and ΔH, and negatively correlated with water‐holding capacity. [ABSTRACT FROM AUTHOR]

The colour of the point cloud provides abundant information for perception tasks such as autonomous driving and virtual reality. However, few prior work studied the automatic colourisation of colourless point clouds. In this paper, the authors propose a novel method named as Point cloud Colorization Network based on Relevance Embedding (PCCN‐RE) relying on three structures: a relevance embedding structure that efficiently captures local information through the calculation of a covariance matrix within nearby points; a weighted pooling structure designed to facilitate the fusion of features; an enhanced spatial transform network structure that keeps the invariance of input point clouds. On the ShapeNetCore dataset, our PCCN‐RE generates more authentic colour than state‐of‐the‐art methods for colourless point clouds and achieves the highest results by obtaining a Peak Signal to Noise Ratio of 9.40 and a Structural Similarity Index of 0.62. [ABSTRACT FROM AUTHOR]

Composite material consisting of Al 2 O 3 and TiC in a matrix of highly textured Ti 3 AlC 2 was fabricated in a two-step fabrication process. The Lotgering orientation factor for {00 l } planes of Ti 3 AlC 2 in the textured top surface plane reached 0.71. Texture analysis showed an orientation relationship among Ti 3 AlC 2 , Al 2 O 3 and TiC grains of [110] Ti 3 AlC 2 // [110] TiC, (001) Ti 3 AlC 2 // (111) TiC, and [110] Ti 3 AlC 2 // [120] Al 2 O 3 , (001) Ti 3 AlC 2 // (001) Al 2 O 3. The texture grained material exhibited excellent mechanical properties, with compressive and flexural strengths of more than 2.5 times those of conventional coarse grained Ti 3 AlC 2 , and fracture toughness and hardness were 50% higher than those of conventional coarse grained Ti 3 AlC 2. The microstructures of textured Ti 3 AlC 2 and reported textured Ti 2 AlC were investigated and compared to interpret the differences in mechanical behavior of the two textured MAX phases. • The crystallographic orientation relationships within highly textured Ti 3 AlC 2 were investigated. • The textured Ti 3 AlC 2 based composite shows very good mechanical properties. • The improvement of the mechanical properties of textured Ti 3 AlC 2 was explained. • The toughening mechanism within textured Ti 3 AlC 2 was investigated. • The mechanical properties of textured Ti 3 AlC 2 and Ti 2 AlC were compared and discussed systematically. [ABSTRACT FROM AUTHOR]

Excessive sheet thickness thinning is the main shortcoming in incremental sheet metal forming (ISF). The focus of the previous studies was to improve the sheet thickness variation in vertical wall components having no inner feature. This study investigates a complex part containing convex, concave, and redundant features due to the frequent customized requirements of the aeronautic industries. In ISF, a redundant area is usually added to the target area to ensure a continuous toolpath. The redundant area effect on sheet thickness variation is the least investigated area. The best toolpath strategy from the literature was employed to see its effectiveness for the complex part investigated in this work. Two profiles in the redundant area were trialed with P-TPIF (positive) and N-TPIF (negative) based on numerical analyses and were verified experimentally. The redundant region profile significantly affects the sheet thickness distribution in the target area in both N-TPIF and P-TPIF. The previously best toolpath strategies, mainly for vertical wall components, do not work effectively for the complex component. [ABSTRACT FROM AUTHOR]

The phenomenon that laboratory pyrolysis experiments produce much wetter gases than those in natural reservoirs is a long-recognized and debated problem in the investigation of natural gases in sedimentary basins. In this study, we explore the discrepancy by pyrolyzing a type II kerogen from the Woodford Shale in Oklahoma, compared with the previous results on the produced natural gases from the Arkoma Basin generated from the same source rock (Liu et al., 2019) with the discussion of gas and isotopic compositions at bulk and position-specific (PS) levels. An improved GC-pyrolysis-GC IRMS method is applied for the determination of PS δ13C of propane produced in the pyrolysis of the Woodford Shale at Easy %R o from 0.76 to 3.27. Kinetic and thermodynamic considerations of the chemical and isotopic compositions of the natural and laboratory pyrolysis gases suggest that the generation of light hydrocarbons involves uni-directional cracking reactions, exchange reactions with water, and likely reversible reactions among light hydrocarbons and other H-containing volatiles. After the gas generation in the unconventional Woodford Shale reservoirs, the C 1 -C 4 gases might have approached close to chemical equilibrium of C 1 -C 3 and isotope equilibrium of C 2 -C 1 and C 3 -C 1 pairs at their peak temperatures. The capping H for the generation of C 1 -C 4 in the Woodford Shale gases appears to have experienced at least partial exchange with the water, while that in the pyrolysis gases is only originated from organic-bound compounds with large kinetic isotope effects (KIE). Our findings indicate that elevated compound-specific and PS δ13C values of propane in the wet-gas cracking stage are significantly influenced by the breakdown of the thermally stable compounds (e.g., remaining kerogen, residues). A first synthesis of PS δ13C and δ2H isotopic compositions of propane from this study and the literature data suggests relatively similar isotopic structures of propane precursors in kerogens. This study demonstrates that PS isotope analysis of propane can contribute to identifying various geological (e.g., maturation, wet-gas cracking, H exchange, diffusion) and biodegradation processes. [ABSTRACT FROM AUTHOR]

Surface modification via low-temperature plasma has an extensive application prospect in different engineering fields due to its comprehensive merits in facilitating the introduction of functional groups and creating more heterogeneous interfaces. Herein, a simple high-temperature plasma method is developed to get novel multiple-phase nanocomposites of core-shell Fe/FeN/Fe 3 C@GN nanoparticles with bifunctional characteristics of microwave absorption (MA) and anti-corrosion. And then, we further investigate the MA properties of Fe/FeN/Fe 3 C@GN nanoparticles after low-temperature NH 3 plasma etching. It is found that surface modification of Fe/FeN/Fe 3 C@GN nanoparticles can generate remarkable changes in specific surface areas, Raman features and MA properties of these nanocomposites. The Fe/FeN/Fe 3 C@GN nanoparticles after NH 3 plasma etching possess excellent MA properties with an optimal reflection loss (RL) of −51.0 dB at an ultra-thin thickness of 1.9 mm with a low filling content of 30 wt% and the corresponding effective absorption bandwidth (EAB < −10 dB) up to 4.7 GHz (13.3–18.0 GHz). The fascinating MA properties of etched Fe/FeN/Fe 3 C@GN nanoparticles may be attributed to the cooperative effect of several points: (i) The NH 3 plasma etch introduces a large number of polar functional groups, which can be regarded as the polarization center to produce more polarization loss; (ii) The appropriate dielectric loss and impedance matching achieve a good balance, and the abundant heterogeneous interface significantly enhances the polarization relaxation loss; (iii) The existence of hetero-nanostructure further improves the multiple reflections and scattering of the propagating microwaves. In addition, this work provides a new strategy for the design and fabrication of core-shell MA materials. [Display omitted] • More defects and functional groups are introduced by surface modification with controllable NH 3 plasma. • Impedance matching is improved by the etching effect of plasma. • Optimal reflection loss can reach −51.0 dB at a thin thickness of only 1.9 mm. • A maximum effective absorption bandwidth of 5.8 GHz at 1.8 mm can be achieved. [ABSTRACT FROM AUTHOR]

Sound Source Localization (SSL) based on microphone arrays nowadays is widely used in the fields of machinery rattle localization, weapon navigation, and robot hearing. However, there is also a need for SSL in some special environments, such as long-distance gas pipelines where there is a risk of leakage. In these environments, arrays built with ordinary microphones can be a safety hazard, which can be compensated by the External Fabry-Perot interferometer (EFPI) fiber-optic sensor's advantages of being uncharged, inexpensive, and highly sensitive. To expand the application areas of microphone array-based SSL techniques, this paper using four EFPI fiber-optic sensors to constructs a 1 m × 1 m × 1 m sensor array, which is used for real-time localization of sound sources based on three-wavelength adaptive intensity demodulation methods and Time Difference Of Arrival (TDOA) localization techniques. An improved method is proposed for the three-wavelength adaptive intensity demodulation method to avoid the occurrence of signal flips. Finally, formulas are provided for this sensor array to quickly calculate the sound source position based on the arrival delay. Several experiments show that the system can achieve sound source localization over a wide range with an average error of less than 3 cm. [ABSTRACT FROM AUTHOR]

The abrasive behavior of M 2 AlX MAX phase materials (Ti 2 AlC, Cr 2 AlC, Ti 2 AlN) was investigated using sandblasting tests with glass beads and alumina particles. Interpretations are based on the specimens' morphologies before and after the sandblasting tests. Overall, the abrasive behavior appears to be related to the brittleness index B , which is a function of the hardness, elastic modulus and fracture toughness. An extension of the analysis to literature data for different hardened and unhardened glasses indicated that this qualitative evaluation factor B can support in the prediction of the abrasive behavior of a wider range of brittle materials. [ABSTRACT FROM AUTHOR]

• The oxidation and creep behaviors of textured Ti 2 AlC and Ti 3 AlC 2 ceramics were characterized. • The oxidation behavior of the two textured materials exhibited anisotropic. • The correlation between the overall parabolic rate constant and oxidation temperature was characterized. • The texturing has a negligible influence on the creep behavior. • The grain-boundary sliding mechanism as supported by the stress exponent can be rationalized by applying a model for superplastic deformation indicating pure-shear motion under stationary conditions accommodated by lattice or grain-boundary diffusion. The oxidation and creep behaviors of textured Ti 2 AlC and Ti 3 AlC 2 ceramics were characterized. The oxidation behavior of the two materials, which was studied in air at temperatures ranging from1000 to 1300 °C, was observed to be anisotropic and the materials exhibited a better oxidation resistance along a direction transverse to the c -axis. The correlation between the overall parabolic rate constant and oxidation temperature of both textured materials was characterized, providing new insights into the oxidation kinetics. The results indicate that the texturing has a negligible influence on the creep behavior in the assessed temperature range of 1000−1200 °C in air, for the applied stresses ranging from 40 to 80 MPa. In this stress regime, the creep behavior of textured Ti 2 AlC and Ti 3 AlC 2 appears to be controlled by grain boundary sliding. This behavior can be rationalized based on a model for superplastic deformation, indicating pure-shear motion under stationary conditions accommodated by lattice or grain-boundary diffusion. [ABSTRACT FROM AUTHOR]

Semi-supervised learning methods aim to address the scarcity of pixel-level annotations in medical image segmentation. Previous approaches typically rely on filtering strategies to obtain pseudo-labels or implement consistency constraints for unlabeled images, which cannot robustly identify regions-of-interest (ROIs) with intricate semantic information. However, this often leads to uncertain predictions in semantically ambiguous areas and results in subpar segmentation outcomes. We observe that this issue stems from the dispersion of the representations of uncertain predictions among the boundaries of the semantically clustered representations of certain predictions. To this end, we propose a novel Uncertainty-Aware Representation Calibration (UA-RC) framework. This framework leverages an efficient uncertainty-aware criterion within a teacher–student SSL architecture to identify the representations of uncertain predictions. Then, UA-RC calibrates them via a semantic contrast paradigm by constructing positive prototypes and negative representations from certain predictions. Furthermore, UA-RC incorporates class-wise memory banks to store massive, diverse representations from training data, facilitating the calibration process and allowing for a better disentanglement of representations related to ROIs and backgrounds. Extensive experiments on four datasets, including Kvasir-SEG, ISIC-2018, BUL-2020, and ACDC, demonstrate the competitive edge of UA-RC over existing alternatives. Codes is available at https://github.com/Wu0409/UARC. [ABSTRACT FROM AUTHOR]

Refractory high entropy alloys (RHEAs) hold great promise for applications requiring high-temperature resistance. In this study, TaMoNbCrTi x (x = 0, 0.25. 0.5, 0.75, 1) RHEAs were fabricated through mechanical alloying (MA) and spark plasma sintering (SPS). The effect of Ti content on the microstructure and mechanical properties of TaMoNbCrTi x RHEAs was investigated. The results revealed that the alloys consisted of a body-centred cubic (BCC) matrix and Laves phase, with the addition of Ti promoting the formation of the Ti(O, N) phase. By employing severe deformation of the ball-milled powder, short sintering time, and the inhibition of precipitated phases on grain growth, the resulting RHEAs exhibited ultrafine grains measuring less than 1 μm. As the Ti content increased, the volume fraction of the Laves phase decreased, transitioning from a reticulated to a dispersed distribution. This shift had a positive influence on the ductility of the alloys. Among the studied compositions, TaMoNbCrTi 0.75 displayed desirable comprehensive mechanical properties with yield strength, compressive strength, and fracture strain of 2696 MPa, 3098 MPa, and 16.8%, respectively. Notably, the ductility exhibited by TaMoNbCrTi 0.75 at room temperature surpassed that of most Cr-containing RHEAs. • Novel TaMoNbCrTi x (x = 0, 0.25, 0.5, 0.75, 1) refractory high-entropy alloys were developed. • The alloys with ultrafine grains were fabricated by mechanical alloying and spark plasma sintering. • The effects of Ti on the microstructure and mechanical properties of TaMoNbCrTi x were studied. • TaMoNbCrTi 0.75 displayed desirable comprehensive mechanical properties. • The excellent yield strength of TaMoNbCrTi x is attributed to various strengthening mechanisms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Quench cooling was experimentally studied by reciprocating moving jet. • Heat transfer mechanisms under different moving speeds was revealed. • Two-dimensional transient heat fluxes were extracted and analyzed. • The heat transfer characteristics of high temperature surface was clarified. Owing to the short time duration and violent nature of boiling regimes, the steel quench cooling on the Run Out Table is extremely complex, this challenges the prediction of the heat transfer coefficient. In this study, we first established a novel reciprocally moving nozzles platform to experimentally investigate the moving quenching process. Then the two-dimensional transient heat flux, wetting behaviors, and heat transfer mechanism that was influenced by the surface temperature, and moving speed were explored. These results revealed the heat flux reduced with the moving speed but elevated with the surface temperature. The wetted area also expanded linearly with the decrease in temperature. With the aid of the developed two-dimensional transient heat flux, the heat quantity was revealed to decrease with the surface temperature at different speeds, but the decline proportion was much lower than that of MHF (maximum heat flux). Notably, the transient heat flux and heat transfer capacity in two-dimensional favored predicting the temperature field of the steel quenching process under industrial conditions. The findings in this work provided the envision to understand the heat transfer mechanism in the moving quenching cooling and provided a flexible method to investigate cooling in a moving state. [ABSTRACT FROM AUTHOR]

Based on the in-situ synthesis process, this study proposes a novel process that introduces lithium salt-modified La 2 O 3p as a precursor into Mg–Li–Al–Zn (LAZ) alloy melt, achieving the controllable preparation of in-situ synthesis Al 3 La/LAZ composite. The as-cast composite was processed into plate by extruded and subsequently rolled at 300 °C. The primary focus of this study was on the microstructure evolution, mechanical mechanism, and deformation behaviour of the rolled composite. The findings suggested that lithium salt-modified La 2 O 3p underwent a series of reactions in LAZ alloy fusant, leading to the in-situ precipitation of Al 3 La phase, refining microstructure and enhancement of the overall strengths of the composite. The strengthening analysis result confirmed that precipitation strengthening and dislocation strengthening are the major contributions. In addition, the microstructure change during deformation was elucidated using EBSD technique. The results revealed that the intragranular slip in the composite changed from primarily prismatic slip to a combination of prismatic and pyramidal slips during tensile deformation. The activation of extension twins did not fully comply with the Schmidt factor (SF) law, with approximately 75 % of the 127 analyzed extension twins following the SF law, during compression deformation. • In LAZ alloys, rare earth alloying was realized by adding La 2 O 3 modified by lithium salt, and Al m La n was formed in-situ. • The rolled composite exhibited excellent mechanical properties, with a UTS∼290.1 MPa, UCS∼432.0 MPa. • In Mg–Li composites, the proportion of activated extension twin variants conforming to SF law was as high as 75 %. [ABSTRACT FROM AUTHOR]

This work presents the systematic investigation of K contents and stable K isotopic compositions of surface waters, groundwater, wastewaters, suspended particles, bed sediments, and fertilizers in the Upper Mun Rive catchment, northeast Thailand. This area is of particular interest because its abundant potash deposits and intensive agricultural activities and urbanization, therefore this will improve our understanding whether the K isotope is robust enough to resist evaporite dissolution and anthropogenic disturbances on tracing silicate weathering in the highly weathered tropical region. The dissolved loads in surface waters and shallow groundwater display the large variation in δ41K diss values from −0.54‰ to +0.09‰ relative to suspended particles (−0.60‰ to −0.41‰), river bed sediments (−0.54‰ to −0.47‰), the upper continental crust (UCC, −0.44 ± 0.05‰), which agrees with the fact that 39K is preferentially retained in weathering products during silicate weathering. The wet and dry seasons difference ranging from −0.05‰ to +0.10‰ δ41K, which is slightly greater than our long-term analytical uncertainty of ±0.06‰. There is likely a limited K input from evaporites dissolution due to weak correlation between δ41K diss values and Cl concentrations or Cl/K ratios in the UMR and world rivers, while a major tributary Takhong River is clearly influenced by the contribution of domestic sewage with lower δ41K and higher δ15N values. Based on a mass balance of K budge, the dissolved K in the UMR is mostly (>90%) derived from silicate weathering in the unpolluted area, this is consistent with previous studies of large river basins, and the evaporite dissolution and other non-silicate sources may not strongly influence dissolved K and δ41K diss values in rivers, even in evaporite-rich catchment. Therefore, K isotopes cannot be used as lithological tracers in catchments, rather the K isotopic fractionation mainly occurs during silicate weathering, such as the formation of secondary minerals which favor light isotope. Hence, the mechanism of K isotopic fractionation linked to secondary minerals K uptake needs further consideration. Overall, these results clearly show that K isotopes could be an ideal indicator to constrain silicate weathering processes and anthropogenic inputs at catchment scale. [ABSTRACT FROM AUTHOR]

This study attempts to examine environmental controls of the underground CO2 concentration, taking the CO2 concentration 4 m beneath the soil as an example. An SVD-PCA-ANN (singular value decomposition-principal component analysis-artificial neural network) preview model is proposed with the data of underground CO2 concentration and 12 environmental variables (the soil and meteorological data). The R2, RMSE, and RPD values of the proposed model are, respectively, 0.8874, 0.3351, and 2.7929, performing better than the popular preview models like SAE (stacked autoencoders), SVM (support vector machine), and LSTM (long short-term memory). It is proved that the underground CO2 concentration can be approximated by a nonlinear function of the considered variables. Soil temperature, salinity, and wind speed are the leading environmental controls, which explain 32.04%, 13.68%, and 11.21% in the variability of the underground CO2 concentration, respectively. Possible mechanisms associated with the environmental controls are also preliminarily discussed. [ABSTRACT FROM AUTHOR]

In order to reduce the difficulty of preparing binder-less cemented carbide and further broaden its application prospects, tungsten carbide toughened by in situ elongated β-Sialon grains was developed via sintering ball-milled WC and α-Si 3 N 4 powders using Al 2 O 3 –ZrO 2 as a sintering aid and transformation additive. The two-step spark plasma sintering of the mixture at 1650 °C with dwelling at 1500 °C for 10 min was conducted under 30 MPa uniaxial pressure, and the densification behaviors, phase transformations, mechanical properties, and microstructures of the produced composites were investigated. The addition of Al 2 O 3 –ZrO 2 reduced the initial temperature of the densification process by approximately 100 °C and its final temperature by 200 °C (compared with the densification temperatures of pure WC and Si 3 N 4 materials) and fully transformed α-Si 3 N 4 to Sialon (Si–Al–O–N) phases. Microstructural characterization data showed that the WC matrix contained homogeneously distributed equiaxed and elongated β-Si 5 AlON 7 grains. The WC composites containing in situ elongated β-Sialon grains exhibited an optimal hardness of 18.93 ± 0.03 GPa and enhanced fracture toughness of 10.43 ± 0.27 MPa m1/2. The toughening mechanism of the β-Sialon phase involved the pull-out of elongated grains and crack bridging. [ABSTRACT FROM AUTHOR]

• The anisotropic mechanical properties of Ti 2 AlN MAX phase was investigated for the first time via a combined experimental and modeling. • Nanoindentation and electron-backscatter diffraction (EBSD) experiments were combined to correlate elastic modulus and hardness of Ti 2 AlN to the crystallographic orientation. • Two different modeling approaches were applied to predict and better understand these anisotropic mechanical properties of Ti 2 AlN MAX phase materials. • Modeling and experiments yielded consistent results with respect to the crystal orientation dependency of both elastic modulus and hardness. Ti 2 AlN MAX phase with a hexagonal crystal structure exhibits great potential as structural material for operation under harsh environments due to its excellent mechanical performance. For a reliable application, a comprehensive understanding of the mechanical behavior, and in particular of the anisotropic properties is needed. Thus, in this study, we combined nanoindentation and electron-backscatter diffraction experiments to correlate elastic modulus and hardness of Ti 2 AlN to the crystallographic orientation. We used two different modeling approaches to better understand, validate, and in the long run to predict the anisotropic mechanical behavior of MAX phase materials. While we observed consistent trends in both experiments and modeling, elastic modulus and hardness showed different dependencies on the crystal orientation. [ABSTRACT FROM AUTHOR]

Plant-specific fasciclin-like arabinogalactan proteins (FLAs) are a subclass of the arabinogalactan proteins (AGPs) superfamily. In addition to AGP-like glycosylated regions, FLAs have conserved fasciclin (FAS) domains. Here, we identified 220 FLA genes from seven Rosaceae species, including 38 FLA gene in pear. Based on gene structure and phylogenetic analysis, the Rosaceae FLA genes can be divided into four classes. The Ks and 4DTv values suggested that the PbrFLA gene family had undergone two whole-genome duplication events occurring at 30–45 MYA and ~ 140 MYA, respectively. Whole-genome duplication (WGD) and transposed duplication (TRD) events mainly drove the evolution of PbrFLA gene family. Most pear FLAs from pear had no intron in their genomic DNA sequences. Pear FLAs possess two highly conserved regions (H1 and H2) and the conserved [Tyr Phe] His ([Y/F]H) motif locating between these two regions. Based on gene expression analysis, most pear FLAs exhibited tissue-specific patterns. PbrFLA10, PbrFLA20, and PbrFLA21 were highly expressed in pollen tubes and self-pollinated styles, indicating FLAs play roles in pollen tube growth and self-incompatibility response. Repression of PbrFLA10/20/21 resulted in the acceleration of pear pollen tube growth. Taken together, our results provided information for understanding the evolution of the PbrFLA gene family and identified the key PbrFLAs genes regulating pollen tube growth. [ABSTRACT FROM AUTHOR]

Isorhynchophylline (IRN), a component of traditional Chinese herb Uncaria rhynchophylla, possesses strong antioxidant activity. Ferroptosis induced by iron overload causes cell oxidative stress after intracerebral hemorrhage (ICH). Therefore, this study aims to explore the effects of IRN on the ferroptosis following ICH. In this study, mouse hippocampal HT-22 cells were treated with ferric ammonium citrate (FAC) alone or together with IRN, and we found IRN reduced the FAC-induced cell damage. Then, cells were treated with IRN following treatment with FAC after transfection with miR-122-5p inhibitor, and the results showed IRN reduced the FAC-induced decrease of miR-122-5p levels and relieved the ferroptosis by detecting ferroptotic marker proteins, iron ion concentration and oxidative stress level; after transfection with miR-122-5p inhibitor, the protective effects of IRN against FAC-induced ferroptosis in these cells were weakened. TP53 (also known as p53) was verified as a target of miR-122-5p by using dual luciferase reporter assay, and restoration of TP53 attenuated the effects of miR-122-5p on ferroptotic marker proteins expression, iron ion concentration and lipid ROS levels, as well as solute carrier family seven member 11 (SLC7A11) mRNA expression. SLC7A11 siRNA reversed the inhibitory effects of IRN on FAC-induced ferroptosis and oxidative stress levels. Subsequently, IRN increased the mNSS score, and decreased brain water content and EB content in ICH model. Moreover, IRN decreased ferroptosis and lipid ROS level, upregulated the expression of miR-122-5p and SLC7A11 mRNA, and inhibited TP53 expression. Our findings reveal that IRN protects neurocyte from ICH-induced ferroptosis via miR-122-5p/TP53/SLC7A11 pathway, which may provide a potential therapeutic mechanism for ICH. [ABSTRACT FROM AUTHOR]

Among all digital representations we have for real physical objects, three‐dimensional (3D) is arguably the most expressive encoding. But due to the limitations of 3D scanning equipment, point cloud often becomes sparse or partially missing. A point cloud super‐resolution (PCSR) method based on geometric constraints is proposed to solve the sparse problem of point clouds: it allows dense point clouds to be generated by sparse point clouds. The method is based on the conditional generative adversarial network including redesigned generator and discriminator for point cloud data specially. Moreover, the method can maintain the shape of the dense point cloud by adding geometric constraints. The contributions of our work are as follows: (1) a PCSR method based on geometric constraints is proposed; (2) add a module for obtaining point cloud neighbourhood information in the generator, called K‐nn operation module; and (3) feature aggregation is performed using the weighted pooling to process the neighbourhood information obtained by the K‐nn operation module. Extensive experimental results demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated CO2 absorption by soils in arid regions, where the absorbed CO2 is conjectured to be finally sequestrated in the "subterranean ocean"—groundwater. This study compares environmental controls of ocean CO2 concentration (surface ocean pCO2) and quasi-ocean CO2 concentration (deep-soil pCO2). We aim to explore the latent relationship, both linear and nonlinear between the environmental variables, and CO2 concentration, utilizing two intelligent algorithms—the partial least linear regression (PLSR) algorithm and the artificial neural network (ANN) algorithm. For quasi-ocean CO2 concentration, RPD <1.4 and R2 <40%. While for ocean CO2 concentration, RPD >1.4 and R2 is 99.7%. Linear relationships between the considered environmental controls and ocean CO2 concentration are proved; however, there is no evident relationship between most of the considered environmental controls and quasi-ocean CO2 concentration. Groundwater level is proved to be a relatively important environmental control on the quasi-ocean CO2 concentration, suggesting groundwater discharge/recharge as a significant modulator of soil CO2 absorption in arid regions. [ABSTRACT FROM AUTHOR]

The article focuses on feasibility study to use spot-scanning proton arc (SPArc) therapy to improve the robustness and dosimetric plan quality. Topics include the radiation oncology society on whether proton beam therapy has been reaching its limitations in terms of plan quality, the development of the Pencil Beam Scanning technique allows the proton system to optimize the energies and the numerous spots to deliver the radiation dose layer by layer and spot by spot in three-dimensional.

Background Purpose Methods and Materials Results Conclusion Intensity‐modulated proton therapy (IMPT) optimizes spot intensities and position, providing better conformability. However, the successful application of IMPT is dependent upon addressing the challenges posed by range and setup uncertainties. In order to address the uncertainties in IMPT, robust optimization is essential.This study aims to develop a novel fast algorithm for robust optimization of IMPT with minimum monitor unit (MU) constraint.The study formulates a robust optimization problem and proposes a novel, fast algorithm based on the alternating direction method of multipliers (ADMM) framework. This algorithm enables distributed computation and parallel processing. Ten clinical cases were used as test scenarios to evaluate the performance of the proposed approach. The robust optimization method (RBO‐NEW) was compared with plans that only consider nominal optimization using CTV (NMO‐CTV) without handling uncertainties and PTV (NMO‐PTV) to handle the uncertainties, as well as with conventional robust‐optimized plans (RBO‐CONV). Dosimetric metrics, including D95, homogeneity index, and Dmean, were used to evaluate the dose distribution quality. The area under the root‐mean‐square dose (RMSD)–volume histogram curves (AUC) and dose–volume histogram (DVH) bands were used to evaluate the robustness of the treatment plan. Optimization time cost was also assessed to measure computational efficiency.The results demonstrated that the RBO plans exhibited better plan quality and robustness than the NMO plans, with RBO‐NEW showing superior computational efficiency and plan quality compared to RBO‐CONV. Specifically, statistical analysis results indicated that RBO‐NEW was able to reduce the computational time from 389.70±207.40$389.70\pm 207.40$ to 228.60±123.67$228.60\pm 123.67$ s (p<0.01$p<0.01$) and reduce the mean organ‐at‐risk (OAR) dose from 9.38±12.80$9.38\pm 12.80$% of the prescription dose to 9.07±12.39$9.07\pm 12.39$% of the prescription dose (p<0.05$p<0.05$) compared to RBO‐CONV.This study introduces a novel fast robust optimization algorithm for IMPT treatment planning with minimum MU constraint. Such an algorithm is not only able to enhance the plan's robustness and computational efficiency without compromising OAR sparing but also able to improve treatment plan quality and reliability. [ABSTRACT FROM AUTHOR]

Steel with a combination of strength and plasticity is prevalently demanded for lightweight design and emission reductions in manufacturing. In this study, a high-strength Cr-Ni-Mo martensitic steel treated by quenching and partitioning (Q&P) and ultrasonic surface rolling (USR) processes was studied for both strength and plasticity enhancement. Specimens were austenitized at 850 °C and then quenched to 240 °C via cooling by water, oil, and normalization in quenching. This was followed by partitioning, in which two groups of specimens were heated to 370 °C and 350 °C for 45 min, respectively. At last, all the specimens were quenched to room temperature with the same methods of quenching. The highest tensile strength increased from 681.73 MPa to 1389.76 MPa when compared to as-received (AR) steel after the Q&P process. The USR process with a static force of 800 N further improved the tensile strength of specimens with high tensile strength after the Q&P process, which improved from 1389.76 MPa to 1586.62 MPa and the product's strength and elongation (PSE) increased from 15.76 GPa% to 15.9 GPa%, while the total elongation showed a mitigatory decrease from 11.34% to 10.02%. Tensile fractures were also studied and verified using a combination of strength and plasticity after a combined process of Q&P and USR. [ABSTRACT FROM AUTHOR]

The transformation from hunting-gathering to the intensive cultivation of cereals, fruits, and nuts has long been discussed. This study combines archaeobotanical evidence from seeds/stones and wood charcoal with historic texts to record the changing role of fruits and nuts in ancient diet on the Chinese Loess Plateau. At the early stage of millet domestication, extensive collection of wild fruits and nuts likely made a vital contribution to the food supply. During the Yangshao period, cereals became the dominant food resource with declining numbers of fruits/nuts, implying a shift from largely gathering to crops cultivation. An increase in the number and ubiquity of Prunus remains during the Longshan time potentially signals the beginnings of fruit cultivation that gains momentum in the Xia-Shang period. Our results indicate that the beginning of fruit cultivation probably coincided with the rise of early urbanism, as seen in West Asia. However, in contrast to West Asia, where arboriculture is seen as prerequisite for the social changes that underpinned urbanization, less evidence for the transformation of fruits and nuts associated with craft specialization was seen in ancient China. As fruits were traditionally used as luxury food and dedication to ancestors, we speculate that the connection between fruits and feasting probably motivated ancient farmers to invest long-term labor into the planting and further the domestication of fruits in China. [ABSTRACT FROM AUTHOR]

Multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) is widely used in stable and radiogenic isotope analysis of various elements because of the extremely high precision and accuracy. At present, stable K, Ca, and radiogenic Sr isotopes are increasingly used as a combined proxy of geological processes. However, time consuming and cumbersome multi-step chemical procedures hinder their development and application. This study presents a method for one-step chromatographic separation of K–Ca–Sr from matrix elements, and the purification procedure is based on AG50W-X12 cation exchange resin without any intervening evaporation step. The K fraction was first collected using 10 mL 2 M (mol L−1) HCl, the Ca fraction was then collected using 18 mL 2 M HCl, and the Sr fraction was collected at last using 10 mL 3 M HCl. K–Ca–Sr isotopic ratios were measured by using MC-ICP-MS (Nu Plasma 3) with a sample–standard bracketing (SSB) method. The stability of our chemical procedure was demonstrated by replicate measurements of ten international reference materials of rocks and seawater. The analytical results obtained for these reference materials are consistent with previously reported values within analytical errors. The external reproducibility of a BCR-2 standard sample was ±0.05‰ (2SD, N = 9) for δ41/39K, ±0.04‰ (2SD, N = 9) for δ44/42Ca, and 0.000012 (2SD, N = 4) for 87Sr/86Sr. Thus, this optimal separation method improves the experimental efficiency and reduces cross-contamination. [ABSTRACT FROM AUTHOR]

The development of lightweight high-temperature materials and their processing methods are receiving increasing attention as the need for improved performance and energy efficiency in aero-engines increase. In this study, the γ-TiAl alloy was successfully soundly bonded to Ti 2 AlNb alloy by pulsed high current (PHC) diffusion welding. The effect of different high level (HL)/low level (LL) of composite pulse current on the microstructure and mechanical properties of the joints have been studied. The representative interface microstructure of PHC-950 °C TiAl/Ti 2 AlNb joint was γ-TiAl substrate/diffusion bonding zone/Ti 2 AlNb impacted zone/Ti 2 AlNb substrate. The diffusion bonding zone was composed of continuous equiaxed α 2 grains and a small amount of B 2 and O phases. The α 2 phase in the diffusion bonding zone was mainly transformed from the γ phase in γ-TiAl substrate and the B 2 and O phase in Ti 2 AlNb substrate. The composite pulse current has a significant promoting effect on the diffusion of elements and joint formation. The diffusion coefficients of D Al and D Nb in hot-pressing (HP, without current effect) diffusion welding joint at interface were 2 × 10−14 m 2/ s and 0.92 × 10−14 m 2/ s , respectively. In the representative PHC-950 °C joint with HL/LL = 12/2 cycles (single cycle duration 3.3 ms), diffusion coefficients of D Al-12/2 , D Nb-12/2 at interface were 19.62 × 10−14 m 2/ s , 13.34 × 10−14 m 2/ s , respectively. Increasing the duration of LL would weaken the current effect. The current waveform parameters were tuned to HL/LL = 12/4 and 12/6 cycles, the diffusion coefficients of D Al-12/4 , D Nb-12/4 D Al-12/6 and D Nb-12/6 were reduced to 15.69 × 10−14 m 2/ s , 12.49 × 10−14 m 2/ s , 15.31 × 10−14 m 2/ s and 10.99 × 10−14 m 2/ s , respectively. The PHC-950 °C joints have the highest shear strength of 257.3 MPa at HL/LL = 12/2 cycles, reaching 83.3% of the base material strength. The HP-950 °C TiAl/Ti 2 AlNb joint has a shear strength of 230.5 MPa, reaching 74.6% of the base material strength. The shear strength of PHC-950 °C joints at HL/LL = 12/4 and 12/6 reduced to 205.3 MPa, 195.8 MPa due to insufficient element diffusion and damages the bonding quality. This work provides a strategy that contributes to reduce the thermal damage of base metal and improve the joint forming efficiency. • Pulse high current diffusion welding was demonstrated for the soundly joining of dissimilar materials of γ-TiAl and Ti 2 AlNb alloys. • The effect of the high-level/low-level ratio of the pulse current on the TiAl/Ti 2 AlNb joints has been studied for the first time. • Elemental diffusion coefficient in TiAl/Ti 2 AlNb joints under pulsed current conditions is numerically analyzed. [ABSTRACT FROM AUTHOR]

Homogeneously dispersed ultrafine CoFe 2 O 4 nanoparticles embedded within N-doped carbon nanofibers (named as CFO@NCNFs) have been fabricated via electrospinning and following heat treatment procedures. The dielectric and magnetic parameters of CFO@NCNFs/paraffin wax composites are regulated through adjusting the concentration of CoFe 2 O 4 to obtain good impedance matching and excellent microwave absorption (MA) properties. Benefiting from the unique structure involving CoFe 2 O 4 @onion-like carbon nanospheres and 3D conductive NCNFs network, as well as the synergistic mechanism between ultrasmall magnetic CoFe 2 O 4 nanoparticles and light mass dielectric NCNFs. The CFO@NCNFs-5 exhibit outstanding MA properties at only 20 wt% filler loading and minimum reflection loss (RL) achieves −47.9 dB (surpass 99.9% MA) at 9.2 GHz with a thin thickness of merely 1.7 mm, and the corresponding effective absorption bandwidth (RL < −10 dB) achieves 5.4 GHz (6.5–11.9 GHz). Moreover, the effective absorption bandwidth (EAB) can be obtained in multiband (3.9–18.0 GHz) by adjusting the thickness of sample layer. Our work indicates that the appropriate incorporation of ultrafine CoFe 2 O 4 nanoparticles encapsulated in NCNFs is a versatile and high-efficiency strategy to integrate lightweight and excellent properties of magnetic carbon-based absorbers. [Display omitted] • 1D CFO@NCNFs were simply synthesized as high-performance microwave absorbers. • Impedance matching is improved by the introduction of small CFO nanoparticles. • Optimal reflection loss can reach −47.9 dB at an ultralow filler loading of 20 wt%. • A maximum effective absorption bandwidth of 5.4 GHz can be achieved. [ABSTRACT FROM AUTHOR]

Mountain uplift produces steep slopes and rapid erosion rates, and hence exposes more silicate rocks to weathering and accelerates the drawdown of atmospheric CO 2 , driving global cooling over the Cenozoic. Riverine potassium (K) and lithium (Li) isotopes are two promising proxies for silicate weathering because the isotopes fractionate during secondary mineral formation associated with weathering and these two elements are highly enriched in silicate rocks. This study explores similarity and difference between K and Li isotope behaviors during weathering across the Lancang River in the southeastern Tibetan Plateau, in order to evaluate the role of these two isotopes in tracing silicate weathering in tectonically active mountains. Dissolved K and Li in the Lancang River mainstream are mainly derived from the dissolution of silicates. River waters are enriched in the heavy isotope of K (−0.35‰ to +0.05‰) and Li (+7.1‰ to +20.4‰) relative to suspended sediments (−0.56‰ to −0.42‰ and −2.3‰ to 0‰, respectively), and the element partitioning between dissolved and suspended loads controls dissolved δ 7 Li and δ 41 K values. Interesting, dissolved δ 7 Li and δ 41 K show the opposite evolution trends toward downstream. As the weathering intensity increases downstream (higher Si/(Na + K)⁎ ratios), the dissolved δ 7 Li values increase from 7.4‰ to 13.6‰, whereas dissolved δ 41 K values decrease from −0.04‰ to −0.26‰. Compared to its headwater with limited weathering, more secondary minerals (e.g., clays) are formed in the lower reaches (e.g., floodplains) with low physical erosion rates and high annual precipitation, driving more 6Li incorporated into clays, thus high dissolved δ 7 Li values downstream. While dissolved δ 41 K values and the fraction of 39K incorporated into secondary minerals are low in floodplains, this is consistent with observations that illite is a main K-bearing phase among clay minerals, and its content in the clay fraction in river sediment decreases as weathering intensity increases. Our study further supported that the increase in Cenozoic seawater δ 7 Li is related to weathering in floodplains rather than weathering of mountains, whereas K isotope fractionation mainly occurs in mountain regions. If Cenozoic seawater δ 41 K rise, as with δ 7 Li change, weathering at higher elevation may exerts more effect on high riverine and seawater δ 41 K values. This study improves our knowledge of K-Li isotope behaviors during present-day silicate weathering, and the response of K-Li isotopes in sedimentary archives to silicate weathering over geological time. • First comparative study of riverine K and Li isotope signatures in Tibetan Plateau. • River water dissolved δ 7 Li values increase while δ 41 K values decrease downstream. • More Li incorporated into clays results in high δ 7 Li values at lower elevation. • K isotope fractionation mainly occurs in mountain regions where more illite formation. • Weathering in high mountains may exerts more effect on riverine and seawater δ 41 K values. [ABSTRACT FROM AUTHOR]

The question of what the ecology communities of the Loess Plateau looked like before the extensive anthropogenic reshaping processes of the late-Holocene has stirred a long debate. A better understanding of these human-induced changes will not only help us understand the extent of paleoeconomic practices, but also inform future conservation actions on this ecologically fragile landscape. This paper presents a systematic study of wood charcoal from a series of archaeological sites, demonstrating that woody plants and woodlands were widely distributed and geographically diverse on the Loess Plateau in response to the East Asian Monsoon. In the Guanzhong Basin, oak (Quercus spp.) woodlands were associated with a few tropical-subtropical taxa, which changed to oak and pine (Pinus spp.) mixed forests on the eastern plateau, while on the northern plateau coniferous woodlands were dominant. On the western Loess Plateau, oak and elm (Ulmus spp.) woodland and spruce (Picea spp.) forests were widespread. The charcoal results suggest that human impacts on the dominant species might have begun as early as ca. 3500 cal yr BP, with oak replaced by Prunus as the dominant taxon, including many economically significant species, such as peaches (P. persica) and apricots (P. armeniaca). Furthermore, the charcoal data show that due to warm and wet climatic conditions in the mid-Holocene, the distribution of tropical-subtropical taxa shifted markedly northwards into the Guanzhong and Tianshui Basins, and the central part of the eastern Loess Plateau, which became characterized by high frequencies of Bamboo. [ABSTRACT FROM AUTHOR]

• Highly textured Ti 2 AlC and Ti 3 AlC 2 ceramics were successfully fabricated by a two-step fabrication process. • The effect of texturing was characterized via XRD, SEM, macro- and micro-indentation as well as the oxidation testing. • The basal planes of both textured carbide MAX phase showed reduced oxidation resistance at 1300 °C. • The impact of the Al ratio for high texture and oxidation resistance of carbide MAX phases that are composed of the same elementals was investigated. Highly textured Ti 2 AlC and Ti 3 AlC 2 ceramics were successfully fabricated by a two-step fabrication process, and the Lotgering orientation factors for {00 l } planes of textured Ti 2 AlC and Ti 3 AlC 2 were calculated as 0.82 and 0.71, respectively. The effect of texturing was evaluated in terms of elastic modulus and hardness by macro- and micro-indentation. Moreover, the oxidation behavior of the MAX phases was investigated at 1300 °C in air, revealing that the oxidation was markedly anisotropic, where the textured side surface exhibited much better oxidation resistance, resulting from the rapid diffusion of Al element within its basal planes to form a protective Al 2 O 3 scale on it. Furthermore, Ti 2 AlC had larger difference regarding oxidation behavior between the top and side surface than Ti 3 AlC 2 , correlated to its higher Al ratio, leading to higher texturing degree and more diffusion pathways to the outer surface to produce an Al 2 O 3 layer already at the initial oxidation stage. [ABSTRACT FROM AUTHOR]

Voltage-controlled voltage source inverters (VSIs) are generally adopted to achieve seamless transfer between islanded mode and grid-connected mode in microgrid applications. However, these two operation modes for VSIs feature different output filters, i.e., LC filters for islanded mode while LCL filters for grid-connected mode, thus leading to different stability performance. In this article, the traditional control strategy based on an outer capacitor voltage loop cascaded with an inner capacitor current active damping loop is investigated in details. The analysis indicates that there exists an inevitable blind area of stability design, where the system cannot be stable under two operation modes at the same time. Therefore, in order to raise available space for system design, this article proposes a stability blind-area-free control design method. The analysis indicates that the proposed stability design is only affected by LC filter parameters under islanded mode. Therefore, the blind area of the traditional control method can be well eliminated, and meanwhile the system robustness against the grid impedance variation under grid-connected mode is improved. The detailed design method is also presented. Simulation and experimental results are finally provided to verify the effectiveness of the analyses and the feasibility of the method. [ABSTRACT FROM AUTHOR]

Pelliales is a basal lineage of the simple thalloid liverworts. Here, we describe a simple thalloid liverwort from the Middle Jurassic Xishanyao Formation of the Turpan–Hami Basin, Xinjiang Uygur Autonomous Region in northwestern China. The thalloid fossil liverwort is described as a new species: Pellites hamiensis (Pelliaceae, Pelliales). Pellites hamiensis nov. sp. resembles the extant species of Pelliaceae in having ribbon-like segments, conspicuous costae that appear as ridges on the ventral surface, rectangular cells with thickened walls adjacent to the margin, and elongated cells in the middle part of the thallus. The occurrence of P. hamiensis nov. sp. extends the fossil records of Pellites back to the Aalenian-Bajocian or Bajocian (ca. 170 Ma) and suggests that the divergence time of the Pelliaceae is no later than the Middle Jurassic. [ABSTRACT FROM AUTHOR]

Spot-scanning proton arc therapy (SPArc) has been proposed to improve dosimetric outcome and to simplify treatment workflow. To efficiently deliver a SPArc plan, it's crucial to minimize the number of energy layer switches (ELS) a sending because of the magnetic hysteresis effect. In this study, we introduced a new SPArc energy sequence optimization algorithm (SPArc_seq) to reduce ascended ELS and to investigate its impact on the beam delivery time (BDT). An iterative energy layer sorting and re-distribution mechanism following the direction of the gantry rotation was implemented in the original SPArc algorithm (SPArc_orig). Five disease sites, including prostate, lung, brain, head neck cancer (HNC) and breast cancer were selected to evaluate this new algorithm. Dose-volume histogram (DVH) and plan robustness were used to assess the plan quality for both SPArc_seq and SPArc_orig plans. The BDT evaluations were analyzed through two methods: 1. fixed gantry angle delivery (BDTfixed) and 2. An in-house dynamic arc scanning controller simulation which considered of gantry rotation speed, acceleration and deceleration (BDTarc). With a similar total number of energy layers, SPArc_seq plans provided a similar nominal plan quality and plan robustness compared to SPArc_orig plans. SPArc_seq significantly reduced the number of ascended ELS by 83% (19 vs.115), 70% (16 vs. 64), 82% (19 vs. 104), 80% (19 vs. 94) and 70% (9 vs. 30), which effectively shortened the BDTfixed by 65% (386 vs. 1091 s), 61% (235 vs. 609 s), 64% (336 vs. 928 s), 48% (787 vs.1521 s) and 25% (384 vs. 511 s) and shortened BDTarc by 54% (522 vs.1128 s), 52% (310 vs.645 s), 53% (443 vs. 951 s), 49% (803 vs.1583 s) and 26% (398 vs. 534 s) in prostate, lung, brain, HNC and breast cancer, respectively. The SPArc_seq optimization algorithm could effectively reduce the BDT compared to the original SPArc algorithm. The improved efficiency of the SPArc_seq algorithm has the potential to increase patient throughput, thereby reducing the operation cost of proton therapy. [ABSTRACT FROM AUTHOR]

• Optimized parameters for the fabrication of bulk Ti 2 AlN via FAST/SPS were derived. • Elastic modulus and hardness were determined via micro-indentation testing. • The abrasive resistance of FAST/SPSed Ti 2 AlN ceramics was characterized via sandblasting tests. • The creep tests on nitride MAX phase (dense Ti 2 AlN) were performed in air in the temperature range of 900–1200 °C for the first time. • The creep behavior of dense Ti 2 AlN ceramic was in comparison with the reported carbide MAX phase ceramics. Highly dense bulk Ti 2 AlN with high purity was successfully fabricated at 1400 °C by Field Assisted Sintering Technology (FAST/SPS) using Ti, Al, TiN as starting powders. Aluminum content appears to play a determinant role to attain high phase purity, where the optimum content has been achieved for a starting molar composition of 1:1.02:1 for Ti, Al, and TiN, respectively. Elastic modulus and hardness were determined via micro-indentation testing at room temperature. Regarding abrasive behavior, sandblasting tests with compressed air of 2 bar were carried out. In addition, creep tests in air in the temperature range of 900−1200 °C were performed to characterize the steady state deformation behavior under constant applied stresses ranging from 20−100 MPa. [ABSTRACT FROM AUTHOR]

In this work, carbon nanotubes (CNTs) were introduced on the pyrolytic carbon (PyC) interface via chemical vapor deposition (CVD) in order to improve the thermal conductivity and mechanical properties of SiC f / SiC composites. The results showed that three major parameters of CVD (a.k.a the deposition temperature, volume fraction of C 2 H 4 and deposition duration) strongly affected the nature of CNTs, as well as the thermal conductivity and mechanical properties of SiC f / SiC composites. The optimal parameters of CVD were found to be 800 °C, 15 vol% C 2 H 4 and 10-30 min. The thermal conductivity and mechanical properties of SiC f / SiC composites were enhanced by the addition of CNTs. However, the excessive deposition of CNTs provoked the formation of pores in the matrix, resulting in the reduction of the thermal conductivity and mechanical properties. The deposition of 5.8 vol % CNTs (corresponding to 20 min CVD deposition) was found to be the best condition to improve the thermal conductivity and mechanical properties of SiC f / SiC. [ABSTRACT FROM AUTHOR]

This paper reports the premolding load effect on the electrical behavior in the initial stage of electric current activated sintering of carbonyl iron powders. An electrical network model is put forward to estimate the uniformity of electric current in a powder compact subjected to different premolding loads in the initial stage. The improvement in current uniformity can be reflected from a simultaneous increase in the number N and the mass fraction θ of conductive particle chains in the compact. Both N and θ are found to follow a power law with the premolding load F for different exponent values. When θ is equal to 1, a critical load is reached, at which point the current flows through all particles during sintering. Using the results of the model and the electrical contact theory, it is also found that only an increased temperature of less than 20 K across the particle contacts. The distribution of temperature is uniform in particles. This is clearly different from the general acceptance that local high temperature is created at contact during electric current activated sintering. The neck formation and growth are thought to be mainly due to heat bonding and electromigration, of which effects on mass transport are pronouncedly enhanced by increasing the bulk temperature. Because of the poor current uniformity and relatively large power dissipation, a soft thermal breakdown is observed in the sample with high initial resistance. A reduction in premolding load may cause an increase in the initial electrical resistance of the compact. Owing to the unique voltage-current characteristic of electric current activated sintering, a higher initial resistance of compact means more thermal energy is involved, consequently producing a higher bulk temperature and getting a better quality of sintering. This also provides theoretical explanation for the experimental results from Inoue and Istomina. [ABSTRACT FROM AUTHOR]

In this work, Amosic-3 SiC/SiC composites were irradiated to 10 dpa and 115 dpa with 300 keV Si ions at 300 °C. To evaluate its irradiation behaviour and investigate the underlying mechanism, nanoindentation, AFM, Raman and electron microscopy were utilized. Nanoindentation showed that although micromechanical properties declined after irradiation, hardness and Young's modulus were maintained better under 115 dpa. AFM manifested differential swelling among PyC interface, fiber and matrix and SEM showed irradiation-induced partial interface debonding, which are both more obvious under 115 dpa. TEM revealed the generation and proliferation of amorphous regions, which is according with the decline and broadening of peaks in Raman spectra. The material was almost completely amorphous after irradiated to 10 dpa while recrystallization occurred under 115 dpa. All results mentioned above contribute to the decline of hardness and Young's modulus and may explain why the micromechanical degradation was more significant under 10 dpa. [ABSTRACT FROM AUTHOR]

Previous studies have shown that significant K isotope fractionation is found in continental weathering, oceanic crust subduction, and plant growth, suggesting that K isotopes could be a potentially important tracer. However, the complicated separation method and analytical conditions limit the precise analysis of potassium isotopes via MC-ICP-MS under "cold" plasma conditions. Here, an improved separation method (single column) permits the complete purification of K from the matrix elements. This method is efficient and convenient and achieves a high yield (99.5 ± 0.6%) and low blank (<10 ng K) under complex matrix extraction conditions. The high-resolution mode with a desolvating nebulizer system was used to increase the signal intensity of 41K+ and 39K+ and reduce 38ArH+, 40ArH+, and some oxide/nitride interference. To eliminate scattered ions or secondary electrons, we used a new dummy bucket to collect high intensity 40Ar+ beams. Besides, potassium isotopes for the standard SRM 3141a and new geological, environmental and biological reference materials such as DNC-1a, JMS-2, and GSB-14 were determined on a Nu Plasma 3 MC-ICP-MS instrument. Overall, the reproducibility of K isotope analysis was better than ±0.06‰ (2SD) that reported in most laboratories around the world. The measured δ41K values of the rock samples are homogeneous, consistent with the previous published data. However, the K isotope composition in soils, sediments, and plants is inhomogeneous and varies greatly from −0.85‰ to −0.25‰. These results show that potassium isotopes have great application potential in the geological, environmental, and biological fields. [ABSTRACT FROM AUTHOR]

Action recognition has been an active research area for many years. Extracting discriminative spatial and temporal features of different actions plays a key role in accomplishing this task. Current popular methods of action recognition are mainly based on two‐stream Convolutional Networks (ConvNets) or 3D ConvNets. However, the computational cost of two‐stream ConvNets is high for the requirement of optical flow while 3D ConvNets takes too much memory because they have a large amount of parameters. To alleviate such problems, the authors propose a Dual Attention ConvNet (DANet) based on dual attention mechanism which consists of spatial attention and temporal attention. The former concentrates on main motion objects in a video frame by using ConvNet structure and the latter captures related information of multiple video frames by adopting self‐attention. Their network is entirely based on 2D ConvNet and takes in only RGB frames. Experimental results on UCF‐101 and HMDB‐51 benchmarks demonstrate that DANet gets comparable results among leading methods, which proves the effectiveness of the dual attention mechanism. [ABSTRACT FROM AUTHOR]