Search

AbstractObjectiveMethodsResultsConclusionTo observe and analyze the efficacy of recombinant tissue-plasminogen activator (rt-PA) thrombolysis combined with Solitaire AB stent mechanical thrombectomy in patients with acute ischemic stroke.Clinical efficacy, neurological function, oxidative stress response, adverse reactions, and quality of life were compared between the two groups.Lower NIHSS scores were observed among patients who received treatment within 2 h after stroke onset when compared with those in a timeframe of 2–6 h, suggesting better neurological function recovery of the patients with early intervention and thus emphasizing the importance of early treatment for patients with stroke onset. Clinical efficacy in the combination group was significantly higher than in the control group (p < 0.05). After treatment, Paraoxonase-1 (PON-1) levels were higher, while lipoprotein-associated phospholipase A2 (Lp-PLA2) and Serum Amyloid A (SAA) levels were lower in the combination group compared to the control group (p < 0.05). The incidence of adverse reactions was significantly lower in the combination group (p < 0.05). At discharge, we observed significantly more patients with good recovery in the combination group when compared to the control group (p < 0.05), suggesting better quality of life of the patients, while this statistical significance was no longer observable at 90 days after discharge (p > 0.05).For acute ischemic stroke patients, rt-PA thrombolysis combined with Solitaire AB stent mechanical thrombectomy treatment is effective. It promotes neurological function recovery, improves vascular stenosis, reduces inflammation and adverse reactions, and enhances quality of life, showing promising clinical applications. [ABSTRACT FROM AUTHOR]

Manganese‐rich layered oxide cathodes of sodium‐ion batteries (SIBs) are extremely promising for large‐scale energy storage owing to their high capacities and cost effectiveness, while the Jahn–Teller (J–T) distortion and low operating potential of Mn redox largely hinder their practical applications. Herein, we reveal that annealing in argon rather than conventional air is a universal strategy to comprehensively upgrade the Na‐storage performance of Mn‐based oxide cathodes. Bulk oxygen vacancies are introduced via this method, leading to reduced Mn valence, lowered Mn 3d‐orbital energy level, and formation of the new‐concept Mn domains. As a result, the energy density of the model P2‐Na0.75Mg0.25Mn0.75O2 cathode increases by ≈50 % benefiting from the improved specific capacity and operating potential of Mn redox. The Mn domains can disrupt the cooperative J–T distortion, greatly promoting the cycling stability. This exciting finding opens a new avenue towards high‐performance Mn‐based oxide cathodes for SIBs. [ABSTRACT FROM AUTHOR]

Manganese‐rich layered oxide cathodes of sodium‐ion batteries (SIBs) are extremely promising for large‐scale energy storage owing to their high capacities and cost effectiveness, while the Jahn–Teller (J–T) distortion and low operating potential of Mn redox largely hinder their practical applications. Herein, we reveal that annealing in argon rather than conventional air is a universal strategy to comprehensively upgrade the Na‐storage performance of Mn‐based oxide cathodes. Bulk oxygen vacancies are introduced via this method, leading to reduced Mn valence, lowered Mn 3d‐orbital energy level, and formation of the new‐concept Mn domains. As a result, the energy density of the model P2‐Na0.75Mg0.25Mn0.75O2 cathode increases by ≈50 % benefiting from the improved specific capacity and operating potential of Mn redox. The Mn domains can disrupt the cooperative J–T distortion, greatly promoting the cycling stability. This exciting finding opens a new avenue towards high‐performance Mn‐based oxide cathodes for SIBs. [ABSTRACT FROM AUTHOR]

Initiating anionic redox chemistry in layered sodium oxide cathodes is a prevalent method to break the capacity limit set by traditional transition metal redox. However, realizing the "win‐win" scenario of high capacity and high cycling stability is still challenging due to the high‐voltage structural distortion and irreversible oxygen loss. Herein, a Mn activation mechanism is unveiled in a novel P2‐Na0.80Li0.08Ni0.22Mn0.67O2 cathode. By elevating the charge cut‐off voltage to 4.3 V, anionic redox is successfully triggered and partial oxygen loss enables the reduction of Mn upon discharge, thus activating more Mn3+/Mn4+ redox reactions in the following cycles and maintaining the total capacity almost unchanged. In situ X‐ray diffraction reveals a complete solid‐solution reaction with an ultralow volume change of 1.04% upon cycling. Consequently, the P2‐Na0.80Li0.08Ni0.22Mn0.67O2 cathode simultaneously accomplishes a high discharge capacity (134.8 mAh g−1 at 0.1 C) and an unexpectedly long cycling life (capacity retention of 91.5% and 85.2% after 500 and 1000 cycles at 10 C, respectively). Via systematic ex situ characterizations and theoretical computations, the charge compensation mechanism upon Na+ insertion/extraction is elucidated. This work broadens the horizons of current oxygen redox chemistry and provides a new path to design high‐performance layered oxide cathode materials for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐ion batteries (AZIBs) are considered as promising large‐scale energy storage devices due to their high safety and low cost. Transition metal dichalcogenides (TMDs) as the potential aqueous Zn‐storage cathode materials are under the research spotlight because of their facile 2D ion‐transport channels and weak electrostatic interactions with Zn2+. In this concept article, we summarize the intrinsic structural features and aqueous Zn‐storage mechanisms of the TMDs‐based electrodes. More significantly, the latest design concepts of TMDs materials for high‐performance AZIBs are discussed in detail from three aspects of interlayer expansion engineering, phase transition engineering, and structure defects engineering. Finally, the current challenges facing TMDs cathodes and possible remedies are outlined for future developments towards efficient, rapid, and stable aqueous Zn‐ion storage. [ABSTRACT FROM AUTHOR]

Layered oxide cathodes for sodium‐ion batteries (SIBs) have drawn increasing attention owing to their fascinating additional capacity contributed by oxygen‐redox chemistry. Unfortunately, excessive oxygen redox incurs an irreversible oxygen release, deteriorating the cyclic stability and compromising the advantage of additional capacity. Significant efforts have been made so far to stabilize lattice oxygen, but the potential advantages associated with oxygen loss have been ignored. Herein, a complementary Mn and O redox mechanism is first revealed in a novel P2‐Na0.75Ca0.04[Li0.1Ni0.2Mn0.67]O2 cathode. The partial oxygen release activates more Mn3+/Mn4+ redox capacities upon cycling, which effectively compensate the capacity loss from O2‐/On‐ redox and thus enable an ultra‐stable cycling performance (capacity retentions of 102.1% and 95.2% over 100 and 200 cycles at 5 C, respectively). The fast Na+ diffusion kinetics of the cathode also ensure an exceptional rate capability (133.1 and 68.8 mAh g‐1 at 0.1 and 20 C, respectively). The electrode crystal/electronic structure evolution and charge compensation mechanism upon sodiation/desodiation have been elucidated via systematic operando measurements and theoretical computations. The complementary chemistry is a universal principle that stabilizes the Na‐storage behaviors of Mn‐based oxide cathodes, providing new opportunities for anionic redox to boost the energy density and cycling life of SIBs simultaneously. [ABSTRACT FROM AUTHOR]

• The flow elongation method was used for the preparation of corn starch films with erythritol and mannitol plasticizers. • Mannitol (DMA) reduced gelatinization in the corn starch system as analyzed by RVA analysis. • Increasing the DMA content enhanced the starch film thickness, water content, and contact angle. • Erythritol (ETH) decreased the water vapor transmittance, crystallinity, and water solubility of starch films. • Interaction of ETH and DMA influenced hydrogen bonding, grid structure, and film properties. In this study, corn films based on corn starch were fabricated through the casting method, and various plasticizers (namely, erythritol and d -mannitol) were incorporated. The study delved into the gelatinization and physicochemical characteristics of these corn starch-based films. Additionally, the impact of different ratios of plasticizers on reductive gelatinization was assessed using RVA analysis. The investigation also encompassed the effects of varying plasticizer ratios on starch granule expansion, amylose dissolution, and amylopectin melting. Interestingly, as the proportion of d -mannitol increased, there were gradual increases in film thickness, water content, and water contact angle, alongside decreases in water vapor permeability, crystallinity, and water solubility of the corn starch-based films. In essence, this research provides a fundamental basis for potential industrial applications of corn starch-based films. [ABSTRACT FROM AUTHOR]

The initial microstructures with the unimodal and bimodal size distribution of γ′ precipitates (referred to as UD and BD, respectively) in CoNi-based superalloy are obtained utilizing different heat treatment regimes. In the present work, compression tests are carried out to investigate the anomalous temperature dependence of strength and the effect of initial microstructure on the deformation mechanism of CoNi-based superalloys. Results show that the anomalous yield occurs above 600 °C, and BD specimen exhibits higher yield stress than UD specimen. In UD specimen, the major deformation mechanisms are pairs of a/2 < 110 > dislocations coupled by APB (antiphase boundary) shearing γ′ precipitates (600–700 °C), and dislocations bypassing the γ′ precipitates accompanied with the SISFs (superlattice intrinsic stacking faults) shear above the peak temperature (900 °C). In BD specimen, the predominant deformation mechanism transitioned from the APB shearing (600 °C) to APB shearing and SISFs shearing (700 °C), and then to the dislocations bypassing the γ′ precipitates together with the SISFs shearing (900 °C). Meanwhile, the relationship between the initial microstructure and deformation mechanism is discussed. Moreover, an attempt is made to quantitatively assess the contribution of secondary γ′ precipitates to the strength at the peak temperature. [ABSTRACT FROM AUTHOR]

Triggering the anionic redox chemistry in layered oxide cathodes has emerged as a paradigmatic approach to efficaciously boost the energy density of sodium‐ion batteries. However, their practical applications are still plagued by irreversible lattice oxygen release and deleterious structure distortion. Herein, a novel P2‐Na0.76Ca0.05[Ni0.23□0.08Mn0.69]O2 cathode material featuring joint cationic and anionic redox activities, where native vacancies are produced in the transition‐metal (TM) layers and Ca ions are riveted in the Na layers, is developed. Random vacancies in the TM sites induce the emergence of nonbonding O 2p orbitals to activate anionic redox, which is confirmed by systematic electrochemical measurements, ex situ X‐ray photoelectron spectroscopy, in situ X‐ray diffraction, and density functional theory computations. Benefiting from the pinned Ca ions in the Na sites, a robust layered structure with the suppressed P2‐O2 phase transition and enhanced anionic redox reversibility upon charge/discharge is achieved. Therefore, the electrode displays exceptional rate capability (153.9 mA h g−1 at 0.1 C with 74.6 mA h g−1 at 20 C) and improved cycling life (87.1% capacity retention at 0.1 C after 50 cycles). This study provides new opportunities for designing high‐energy‐density and high‐stability layered sodium oxide cathodes by tuning local chemical environments. [ABSTRACT FROM AUTHOR]

Remote sensing and ground vegetation observation data show that climate warming promotes global vegetation greening, and the increase in air temperature in High Mountain Asia (HMA) is more than twice the global average. Under such a drastic warming in climate, how have the vegetation dynamics in HMA changed? In this study, we use the Normalized Difference Vegetation Index (NDVI) from 1982 to 2015 to evaluate the latest changes in vegetation dynamics in HMA and their climate-driving mechanisms. The results show that over the past 30 years, HMA has generally followed a "warm-wet" trend, with temperatures charting a continuous rise. During 1982–1998 precipitation increased (1.16 mm yr−1), but depicted to reverse since 1998 (− 2.73 mm yr−1). Meanwhile, the NDVI in HMA increased (0.012 per decade) prior to 1998, after which the trend reversed and declined (− 0.005 per decade). The main reason for the browning of HMA vegetation is the dual effects of warming and precipitation changes. As mentioned, the increase in air temperature in HMA exceeds the global average. The increase of water vapor pressure deficit caused by global warming accelerates the loss and consumption of surface water, and also aggravates the soil water deficit. That is to say, the abnormal increase of land evapotranspiration far exceeds the precipitation, and the regional water shortage increases. Climate change is the primary factor driving these vegetation and water dynamics, with the largest proportion reaching 41.9%. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐storage behaviors of MoS2‐based cathodes mainly rely on the ion‐(de)intercalation at edge sites but are limited by the inactive basal plane. Herein, an in‐situ molecular engineering strategy in terms of structure defects manufacturing and O‐doping is proposed for MoS2 (designated as D‐MoS2‐O) to unlock the inert basal plane, expand the interlayer spacing (from 6.2 to 9.6 Å), and produce abundant 1T‐phase. The tailored D‐MoS2‐O with excellent hydrophilicity and high conductivity allows the 3D Zn2+ transport along both the ab plane and c‐axis, thus achieving the exceptional high rate capability. Zn2+ diffusion through the basal plane is verified by DFT computations. As a proof of concept, the wearable quasi‐solid‐state rechargeable Zn battery employing the D‐MoS2‐O cathode operates stably even under severe bending conditions, showing great application prospects. This work opens a new window for designing high‐performance layered cathode materials for aqueous Zn‐ion batteries. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐storage behaviors of MoS2‐based cathodes mainly rely on the ion‐(de)intercalation at edge sites but are limited by the inactive basal plane. Herein, an in‐situ molecular engineering strategy in terms of structure defects manufacturing and O‐doping is proposed for MoS2 (designated as D‐MoS2‐O) to unlock the inert basal plane, expand the interlayer spacing (from 6.2 to 9.6 Å), and produce abundant 1T‐phase. The tailored D‐MoS2‐O with excellent hydrophilicity and high conductivity allows the 3D Zn2+ transport along both the ab plane and c‐axis, thus achieving the exceptional high rate capability. Zn2+ diffusion through the basal plane is verified by DFT computations. As a proof of concept, the wearable quasi‐solid‐state rechargeable Zn battery employing the D‐MoS2‐O cathode operates stably even under severe bending conditions, showing great application prospects. This work opens a new window for designing high‐performance layered cathode materials for aqueous Zn‐ion batteries. [ABSTRACT FROM AUTHOR]

Layered transition metal oxides (TMOs) are appealing cathode candidates for sodium‐ion batteries (SIBs) by virtue of their facile 2D Na+ diffusion paths and high theoretical capacities but suffer from poor cycling stability. Herein, taking P2‐type Na2/3Ni1/3Mn2/3O2 as an example, it is demonstrated that the hierarchical engineering of porous nanofibers assembled by nanoparticles can effectively boost the reaction kinetics and stabilize the structure. The P2‐Na2/3Ni1/3Mn2/3O2 nanofibers exhibit exceptional rate capability (166.7 mA h g−1 at 0.1 C with 73.4 mA h g−1 at 20 C) and significantly improved cycle life (≈81% capacity retention after 500 cycles) as cathode materials for SIBs. The highly reversible structure evolution and Ni/Mn valence change during sodium insertion/extraction are verified by in operando X‐ray diffraction and ex situ X‐ray photoelectron spectroscopy, respectively. The facilitated electrode process kinetics are demonstrated by an additional study using the electrochemical measurements and density functional theory computations. More impressively, the prototype Na‐ion full battery built with a Na2/3Ni1/3Mn2/3O2 nanofibers cathode and hard carbon anode delivers a promising energy density of 212.5 Wh kg−1. The concept of designing a fibrous framework composed of small nanograins offers a new and generally applicable strategy for enhancing the Na‐storage performance of layered TMO cathode materials. [ABSTRACT FROM AUTHOR]

Na 0.44 MnO 2 has drawn great attention as a promising cathode material for sodium-ion batteries (SIBs) owing to its unique tunnel-type structure that allows facile Na+ insertion/extraction. We here report the controllable preparation of Na 0.44 MnO 2 nanowires (NMO NWs) through electrospinning and annealing processes and their SIB cathode application to boost the ionic diffusion dynamics and cyclic stability. The well-shaped NMO NWs with diameters of 50–200 nm effectively favour the easy access to electrolyte, facilitate the electrons/Na+ ions transportation, and retard the active materials fracture/pulverization upon prolonged cycling. Consequently, fascinating electrochemical performance in terms of high-rate capability (120.4 mAh g−1 at 0.1C; 31.7 mAh g−1 at 50C) and unprecedentedly long cycling life (89% capacity retention after 3300 cycles) is achieved. Furthermore, the underlying Na-ion storage mechanism and migration kinetics have been pioneeringly elucidated by a combination study of ex-situ structure/valence analyses and first-principles computations. The pseudocapacitive behaviour of NMO NWs electrode is also identified to benefit the high-rate performance. Finally, a pouch-type sodium-ion full battery assembled by the NMO NWs cathode and hard carbon nanofibers anode delivers an admirable energy density of 165.3 Wh kg−1 and an outstanding capacity retention of 88.57% over 200 cycles, showing great prospects. Well-shaped Na 0.44 MnO 2 nanowires featuring diameters in the range of 50–200 nm enable highly reversible Na+ insertion/extraction through the tunnel-type structure with low ionic diffusion energy barrier and proper pseudocapacitive contribution, demonstrating outstanding high-rate capability and unprecedentedly long cycling life as a cathode for sodium-ion batteries. Image 1 • Well-shaped Na 0.44 MnO 2 nanowires were prepared via a controllable and green electrospinning-annealing route. • Na 0.44 MnO 2 nanowires cathode enabled outstanding rate capability and unprecedented cycling stability in Na-ion batteries. • Highly reversible Na+ (de)insertion with low diffusion barrier and proper pseudocapacitive contribution was demonstrated. • A high-energy and long-life pouch-type Na-ion full battery was rationally constructed. [ABSTRACT FROM AUTHOR]

An autoxidation treatment of short-time milled original powders was introduced for the synthesis of MgB2 superconductors and the critical current density Jc of the sintered MgB2 bulks was measured. It is unusually found that the undoped MgB2 bulks sintered with those autoxided milled original powder exhibit abnormally excellent Jc (above 1×104 A cm-2 even at 3.5 T, 20 K). Combined with the investigation of sintering process, it was found that the autoxidation treatment of the milled powders affects the subsequent sintering process dramatically and finally leads to the formation of MgB2 nanocrystalline with lots of dislocation and self-generated MgO nanoinclusions embedded in them. This unique microstructure brought up a significant improvement of Jc at high fields. Besides, the formation mechanism of this unique microstructure during the sintering process was also discussed in detail. It suggested that the MgO preformed by the reaction between Mg and B2O3 in the interface between Mg particles and B particles might serve as nuclei for the heterogeneous nucleation of the MgB2 phase and finally be included in the MgB2 grains as they grew up. The present method provides possible windows for the development of practical MgB2 superconductors without adopting expensive nanodopants. [ABSTRACT FROM AUTHOR]

MgB2 samples with 3 at. % Cu addition were synthesized by means of in situ sintering at different temperatures (525, 575, and 850 °C). Based on thermal analysis, phase identification, and microstructural observation, it is first found that the Cu addition mainly concentrates at the edge of the void in the form of Mg2Cu and thus does not degrade the grain coupling of MgB2 phase in the low-temperature sintered sample. As sintering temperature rises to 850 °C, the MgB2 grains grow larger and some Cu addition may form MgCu2 nanoinclusions distributing in the MgB2 grains through the reaction, 2Mg2Cu(L)+6B=3MgB2+MgCu2. As a result, the mechanism of enhancement in the Jc of the Cu-doped MgB2 samples varies distinctly from the grain-boundary pinning to the possible MgCu2 nanoinclusions pinning as the sintering temperature increases from low temperature to high-temperature. [ABSTRACT FROM AUTHOR]

In this paper, the evolution of precipitate phases in 9CrMoCoB (CB2) steel after tempering at 650 °C for different times has been investigated using transmission electron microscopy. As the tempering time prolonged from 0 to 100 h, four types of secondary phases consisting of M 3 C, M 2 X, M 7 C 3 and M 23 C 6 were identified in the experimental steel. It was found that the needle-like M 3 C carbides could be precipitated during both the air cooling process after austenization and the early stage of tempering. After tempering for 15 to 120 min, fine M 2 X particles were observed. The precipitation and growth of M 2 X were derived from the partially consumption of M 3 C carbides. After tempering for 50 h, M 2 X disappeared, while the rod-like M 7 C 3 carbides were observed to be precipitated independent of the early formed M 3 C precipitates. After tempering for 100 h, only M 23 C 6 carbides persisted, of which the number density and size kept increasing throughout 30 min to 100 h owing to their high thermostability. In addition, the precipitation mechanisms of the four types of precipitates were explained, and the relationship between the measured hardness values and microstructure was discussed. • Precipitates evolution in 9CrMoCoB (CB2) steel during tempering has been investigated. • M 3 C precipitated during both the air cooling process after austenization and the early stage of tempering. • The precipitation sequence can be given as follows: M 3 C → M 2 X → M 7 C 3 → M 23 C 6. • Hardness reduction rate of specimens decreased with the tempering time increasing. [ABSTRACT FROM AUTHOR]

Abstract The decomposition of metastable β phase and microstructural evolution of a forged Ti-22Al-25Nb orthorhombic alloys were investigated by the electron microscopes and phase identification. For the near-Ti 2 AlNb alloy, the processing temperatures were super-transus (over the transition temperature of the β phase). β phase was ordered before its decomposition and cooling rate could strongly influence the precipitation of the explored Ti-22Al-25Nb alloy. Water quenching could prevent the transformation related to diffusion and air cooling hindered the occurrence of fine lenticular O phase in the matrix. Comparison with previous researches and selected area diffraction patterns revealed that there did exist a displacive precursor that provided nucleation sites for the α 2 phase during B2 → α 2 transition. Due to the transient structure and diffusive gradient of Nb component during the transformation, a "cellular structure" was assembled and quantities of equiaxed α 2 precipitates were acquired. Simultaneously allotriomorph α 2 precipitates inclined to grow into coarse plates on the boundaries, which would have a detrimental effect on the mechanical properties of the alloy. Widmanstätten structure was formed during the (B2+α 2 +O) field and massive transformation of lenticular O phase occurred in the (B2+O) field. Highlights • Effect of cooling rates on the decomposition of B2 phase in the Ti 2 AlNb-based alloy is presented. • Precipitation and microstructural evolution during slow-cooling process are discussed in detail. • The mechanism of the formation of cellular structure was put forward and verified. [ABSTRACT FROM AUTHOR]

Abstract The morphological evolution and coarsening kinetics of γ′ precipitates in the γ'+γ area of a Ni 3 Al-based alloy during isothermal aging at temperature range of 800 °C to 1000 °C have been investigated. For the aging temperature above 900 °C, the average size of γ′ precipitates increases and the morphology of γ′ precipitates gradually changes from cuboidal to strip-like and L-shaped with increasing aging time up to 50 h. The temporal evolution of the average size of γ′ precipitates is evaluated by the experimentally measured data and it suggests that the cube rate law fits better for experimental data at the early stage coarsening, while the square rate law fits better for the later stage coarsening. Moreover, using these determined values of coarsening rate constants which determined by using a coarsening rate equation based on the LSEM model, the activation energy of the early stage and later stage coarsening have been calculated as 174.2 kJ/mol and 186.3 kJ/mol, respectively. Highlights • The morphology evolution of γ′ precipitate in a Ni 3 Al-based alloy was studied. • The coarsening process of γ′ precipitates occurs in two stages. • The cube law rate exhibits a better fit for the early stage coarsening. • The square law rate fits better for the later stage coarsening. • The activation energy of the early and later stage coarsening was calculated. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Orientation relationships of (1 1 1) NbN //(1 1 2) NbCrN and 0 1 1 ¯ NbN / / 1 1 ¯ 0 NbCrN have been observed. • NbN provides nucleation site and niobium for the formation of secondary NbCrN. • Secondary NbCrN tends to consume NbN by nucleation and growth mechanism. Abstract Precipitation behavior of Z-phase (NbCrN) is investigated in 25Cr-20Ni-Nb-N austenitic stainless steel during long-term aging. The early precipitation of secondary NbN appears when the steel is aged for 100 h, and the secondary NbCrN precipitates adhere to the pre-existing NbN particles during the subsequent aging. A semi-coherent relation between (1 1 1) NbN and (1 1 2) NbCrN is identified, which provides favorable sites for the nucleation of secondary NbCrN on secondary NbN. Subsequently, secondary NbN will dissolve to supply niobium and nitrogen for the growth of secondary NbCrN. [ABSTRACT FROM AUTHOR]

Abstract Curing processes of weak- and strong-crosslinking curing systems, e.g. , epoxy asphalt and dicyandiamide cured epoxy resin systems, were studied by mechanical method of dynamic shear rheometer (DSR) and thermal method of differential scanning calorimetry (DSC), respectively. Results indicate that the two approaches are both sensitive to the whole curing process for strong-crosslinking system, whose curing exothermic process matches its mechanical properties' development. But for weak-crosslinking system, i.e. , incompletely cured rubber-like one, whose mechanical properties' improvement lags behind its curing exothermic process, DSC is sensitive in initial stage of curing reaction, and DSR is sensitive after gel point. Furthermore, with Avrami equation, it is possible to control the curing processes for preparing products with needed mechanical properties by DSR. Therefore, although DSC method is classical, DSR and alike mechanical methods should be comprehensively evaluated in terms of involved curing systems at different curing stages as well as researchers' study purposes. Highlights • DSC and DSR are both sensitive to whole curing process of strong-crosslinking system. • For weak-crosslinking system, DSR is sensitive after gelation. • DSR is helpful to control curing process for obtaining needed mechanical properties. [ABSTRACT FROM AUTHOR]

Combined with the thermal analysis and phase identification, it is found that during the low-temperature sintering process of the SiC-doped MgB2 samples, the Cu addition can improve both the reaction between Mg and B and the reaction between Mg and SiC and thus accelerate the formation of the MgB2 phase with effective C substitution for B. Accordingly, we successfully synthesize MgB2 bulks with excellent critical current density (Jc) by proper amount of Cu and SiC multidoping sintered at 575 °C for only 5 h. [ABSTRACT FROM AUTHOR]

Abstract: Maricite NaFePO4 nanodots with minimized sizes (≈1.6 nm) uniformly embedded in porous N‐doped carbon nanofibers (designated as NaFePO4@C) are first prepared by electrospinning for maximized Na‐storage performance. The obtained flexible NaFePO4@C fiber membrane adherent on aluminum foil is directly used as binder‐free cathode for sodium‐ion batteries, revealing that the ultrasmall nanosize effect as well as a high‐potential desodiation process can transform the generally perceived electrochemically inactive maricite NaFePO4 into a highly active amorphous phase; meanwhile, remarkable electrochemical performance in terms of high reversible capacity (145 mA h g−1 at 0.2 C), high rate capability (61 mA h g−1 at 50 C), and unprecedentedly high cyclic stability (≈89% capacity retention over 6300 cycles) is achieved. Furthermore, the soft package Na‐ion full battery constructed by the NaFePO4@C nanofibers cathode and the pure carbon nanofibers anode displays a promising energy density of 168.1 Wh kg−1 and a notable capacity retention of 87% after 200 cycles. The distinctive 3D network structure of very fine NaFePO4 nanoparticles homogeneously encapsulated in interconnected porous N‐doped carbon nanofibers, can effectively improve the active materials' utilization rate, facilitate the electrons/Na+ ions transport, and strengthen the electrode stability upon prolonged cycling, leading to the fascinating Na‐storage performance. [ABSTRACT FROM AUTHOR]

Prussian blue analogues with tunable open channels are of fundamental and technological importance for energy storage systems. Herein, a novel facile synthesis of nickel-cobalt hexacyanoferrate/reduced graphene oxide (denoted as Ni-CoHCF/rGO) nanocomposite is realized by a reverse microemulsion method. The very fine Ni-CoHCF nanoparticles (10–20 nm) are homogeneously anchored on the surface of reduced graphene oxide by electrostatic adsorption and reduced graphene oxide is well-separated by Ni-CoHCF particles. Benefiting from the combined advantages of this structure, the Ni-. It CoHCF/rGO nanocomposite can be used as electrodes for both supercapacitors and sodium ion batteries exhibits excellent pseudocapacitve performance in terms of high specific capacitance of 466 F g −1 at 0.2 A g −1 and 350 F g −1 at 10 A g −1 , along with high cycling stabilities. As a cathode material for sodium ion batteries, it also demonstrates a high reversible capacity of 118 mAh g −1 at 0.1 A g −1 , good rate capability, and superior cycling stability. These results suggest its potential as an efficient electrode for high-performance energy storage and renewable delivery devices. [ABSTRACT FROM AUTHOR]

Aimed at clarifying δ-ferrite formation in fusion welding of ferritic/martensitic steels, effects of cooling rates on δ/γ transformation and martensitic transformation in modified ferritic heat resistant steel are investigated by high-speed quenching dilatometer equipment and microstructure examination. In heating stage, γ-austenite starts to transform into δ-ferrite at 1250 ± 20 °C. With respect to cooling stage, at cooling rate of 1 °C/s, γ → δ transformation takes place at temperatures above 1250 °C. Stripe-shaped δ-ferrite is produced at 1 °C/s, and under higher cooling rates (30, 50 and 200 °C/s), δ-ferrite exhibits block morphology. The different levels to which the δ → γ transformation proceeds would result in the variation in austenite grain size and the amount of δ-ferrite, affecting the subsequent martensitic formation. Effects of cooling rates on martensite start temperature have been discussed in terms of austenite grain size and austenite chemical stability. [ABSTRACT FROM AUTHOR]

Transformable 9Cr oxide dispersion strengthened (ODS) steel was prepared by mechanical milling and consolidated by spark plasma sintering (SPS). Microstructural features in different fabrication stages were studied by X-ray diffraction, optical microscopy, scanning and transmission electron microscopy. In the mechanical milling stage, deformed, amorphous and fractured Y 2 O 3 particles are identified, and certain amount of Y 2 O 3 may decompose into the matrix. As a rapid densification technique, SPS will retain the high density of dislocations produced in milling. For both as-sintered and as-annealed 9Cr-ODS steels, interface structures and orientation relationships between Y 2 O 3 and the iron matrix have been examined, as well as the size distributions of Y 2 O 3 particles. The as-sintered 9Cr-ODS steel exhibits higher strength at room temperature than the as-annealed one, and contributions of various microstructural features to yield strength of 9Cr-ODS steels in both conditions have been evaluated. [ABSTRACT FROM AUTHOR]

Transition metal sulfides hold great potential for achieving high-performance supercapacitors. Herein, we have rationally fabricated NiCo 2 S 4 nanosheets within three-dimensional (3D) reduced graphene oxide (rGO) via a facile approach. In this unique hierarchical architecture, the 3D rGO serve as interconnected porous matrices that are highly conductive, thus allowing the hybrid electrode to realize fast ionic and electronic transportation. Benefiting from the synergistic effect between NiCo 2 S 4 and rGO, the hybrid electrode delivers substantially improved energy storage capability in a three-electrode system, with high cycling stability of 90% capacitance retention (5000 cycles, 5 A g −1 ). An asymmetric supercapacitor was fabricated with the NiCo 2 S 4 -rGO composites as positive electrode and porous carbon framework-rGO as negative electrode. The asymmetric supercapacitor exhibits a high energy density of 36 Wh kg −1 along with an excellent cycling performance of 95% capacitance retention over 8000 cycles. This presents a promising way to engineer advanced hybrid materials of transition metal sulfides for high energy density supercapacitors. [ABSTRACT FROM AUTHOR]

NaVPO4F has received a great deal of attention as cathode material for Na-ion batteries due to its high theoretical capacity (143 mA h g−1), high voltage platform, and structural stability. Novel NaVPO4F/C nanofibers are successfully prepared via a feasible electrospinning method and subsequent heat treatment as self-standing cathode for Na-ion batteries. Based on the morphological and microstructural characterization, it can be seen that the NaVPO4F/C nanofibers are smooth and continuous with NaVPO4F nanoparticles (≈6 nm) embedded in porous carbon matrix. For Na-storage, this electrode exhibits extraordinary electrochemical performance: a high capacity (126.3 mA h g−1 at 1 C), a superior rate capability (61.2 mA h g−1 at 50 C), and ultralong cyclability (96.5% capacity retention after 1000 cycles at 2 C). 1D NaVPO4F/C nanofibers that interlink into 3D conductive network improve the conductivity of NaVPO4F, and effectively restrain the aggregation of NaVPO4F particles during charge/discharge process, leading to the high performance. [ABSTRACT FROM AUTHOR]

To study the hot deformation behavior of Ni 3 Al-based alloy, hot compression tests were conducted in the temperature range of 1050–1250 °C with the strain rates from 0.01 to 10 s −1 . With the increase in deformation temperature and the decrease in strain rate, flow stress of the Ni 3 Al-based alloy would be decreased. Based on the obtained constitutive equation, the calculated values of peak flow stress are in good agreement with the experimental ones, and the activation deformation energy is determined as 802.71 kJ/mol. Moreover, by dynamic material model (DMM), processing maps of the hot-deformed Ni 3 Al-based alloys are established. It is indicated that the optimum processing parameters for the studied alloy correspond to deformation temperature of 1250 °C and strain rates from 0.01 to 0.1 s −1 . Specimens deformed under the optimum processing conditions exhibit fine and uniform grains, which is a typical dynamic recrystallization (DRX) microstructure. The DRX degree could be effectively enhanced with the increase of deformation temperature and the decrease of strain rate. [ABSTRACT FROM AUTHOR]

Lithium metal is considered a "Holy Grail" of anode materials for high-energy-density batteries. However, both dendritic lithium deposition and infinity dimension change during long-term cycling have extremely restricted its practical applications for energy storage devices. Here, a thermal infusion strategy for prestoring lithium into a stable nickel foam host is demonstrated and a composite anode is achieved. In comparison with the bare lithium, the composite anode exhibits stable voltage profiles (200 mV at 5.0 mA cm-2) with a small hysteresis beyond 100 cycles in carbonate-based electrolyte, as well as high rate capability, significantly reduced interfacial resistance, and small polarization in a full-cell battery with Li4Ti5O12 or LiFePO4 as counter electrode. More importantly, in addition to the fact that lithium is successfully confined in the metallic nickel foam host, uniform lithium plating/stripping is achieved with a low dimension change (merely ≈3.1%) and effective inhibition of dendrite formation. The mechanism for uniform lithium stripping/plating behavior is explained based on a surface energy model. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) have been investigated as promising alternatives to lithium-ion batteries (LIBs) because of the rich sodium natural resource. Exploring suitable electrode materials is still a great challenge for the practical applications of SIBs. Herein, we demonstrate a novel three-dimensional porous carbon-coated graphene (3D PG@C) anode for SIBs using silica as the porous template combined with a subsequent polyaniline (PANI)-converted carbon coating. The synthesis process mainly consists of deposition of SiO 2 nanoparticles on graphene surface, in situ polymerization of aniline monomers and carbonization of PANI and etching of SiO 2 . The resultant 3D PG@C composite possesses high electrical conductivity, rapid ion insertion, sufficient active sites, short ionic diffusion distance and stable structural integrity for efficient Na-storage. As an anode material for SIBs, the 3D PG@C composite delivers excellent Na-storage performance, in terms of high initial discharge capacity (824 mAh g −1 at 50 mA g −1 ), large reversible capacity and long cyclability (323 mAh g −1 after 1000 cycles at 1000 mA g −1 ) and remarkable rate capability (207 mAh g −1 at 10000 mA g −1 ). The design strategy reported in this work would provide a promising approach toward high-stable and long-life carbonaceous anode materials for SIBs. [ABSTRACT FROM AUTHOR]

Internal Mg diffusion (IMD) process can produce MgB 2 superconducting wires with engineering critical current density several times higher than that of traditional powder in tube processed wires, which makes it an attractive and promising method for mass producing practical MgB 2 wires. However, the MgB 2 layer growth stops shortly after the onset of the heat treatment and unreacted B always remained in the MgB 2 layer within MgB 2 wires, negatively affecting the J e performance. Thus it is of great importance to have an in-depth understanding of the mechanism of reaction between Mg rod and B powder forming the MgB 2 layer within IMD wires during heat treatment, and identify the critical factor that controls the formation rate of MgB 2 layer. In present work, the kinetics mechanism of reaction between Mg and B forming MgB 2 layer in the internal Mg diffusion (IMD) processed MgB 2 wires were systemically studied in present work. It was found that the reaction between Mg and B forming MgB 2 layer during the heating treatment is controlled by varied mechanisms. At initial stage, the formation of MgB 2 layer is mainly determined by the rate of chemical reaction between liquid Mg and B powder. As the reaction processes and the thickness of synthesized MgB 2 layer increases, the slow Mg diffusion-limited mechanism gradually becomes dominant at final stage. On the basis, herein Mg rod with a thin Cu coating is proposed to replace normal Mg rod in IMD procedure to accelerate the formation of MgB 2 layer within wires. As a result, Cu coating can change the kinetics mechanism of MgB 2 layer formation and enable the formation of MgB 2 layer to get rid of the restriction of slow Mg diffusion. Complete dense MgB 2 layer without B-rich or unreacted B regions was successfully synthesized within Cu coated IMD wires with larger diameter (1.03 mm) at temperature as low as 600 °C (below Mg melting point). The kinetics mechanism of MgB 2 layer formation determined in our work can provide a valuable guide for optimizing processing parameters of IMD MgB 2 wires. Moreover, the Cu coating technique proposed here opens a promising way to fabricate practical high performance IMD wires at low heating temperature. [ABSTRACT FROM AUTHOR]

Cold-rolled (CR) type 347H austenitic heat-resistant steel is investigated in this study, and the main strengthening phase, NbC, experiences the procedures of dissolution and precipitation twice, with the increase of deformation degree from 30% to 90%. Most of the primary NbC particles, remained during the solution treatment, dissolve in the austenitic matrix when the deformation degree is 30%, and rod-like NbC generates along the prior austenite grain boundary. Further deformation leads to the fragmentation and decomposition of the rod-like NbC. Until the cold rolling reduction reaches 90%, the dissolved NbC secondarily precipitates into nanoparticles and disperses throughout the martensite induced by deformation. The tensile strength of the 90% cold-deformed specimen, 1418 MPa, is enhanced by three times in contrast with the undeformed one. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis of graphene-like MoS 2 /graphene hybrid by a facile lithium-assisted sonication method and its cathode application for rechargeable Mg batteries. Instrumental analyses elucidate that the composite displays a three-dimensional (3D) porous architecture constructed by exfoliated single or few MoS 2 layers, and some graphene is intercalated in the MoS 2 gallery with an enlarged interlayer spacing from 0.62 to 0.98 nm. The obtained MoS 2 /graphene hybrid exhibits high electrochemical performance with a remarkable capacity (115.9 mA h g −1 ) and good cyclic stability (82.5 mA h g −1 after 50 cycles). This is owing to the synergistic effect between the graphene-like MoS 2 and the highly conductive graphene, which can effectively facilitate the Mg 2+ ions diffusion and electrons transfer, provide abundant active sites for Mg 2+ intercalation, and prevent structural collapse upon prolonged cycling. [ABSTRACT FROM AUTHOR]

Instantaneous high temperature improved the low-temperature sintering efficiency of the un-doped MgB 2 superconductor, and the MgB 2 was rapidly synthesized at 600 °C for only 2 h. In addition to the refinement of MgO impurity particles, the sudden high temperature induced defects within the MgB 2 grains, e.g. twinning crystal, and the J c performance is therefore significantly enhanced, about 2.2 × 10 3 A·cm − 2 at 4 T for bulk sample. Differed from the two-dimensional nucleation growth mode of the MgB 2 grains in the high-temperature sintered un-doped sample, the low-temperature sintered MgB 2 grains accord with the dislocation growth mechanism, relying on the thermal-stress-triggered twinning crystal. [ABSTRACT FROM AUTHOR]

Nitrogen-doped hierarchically porous carbon (NHPC) materials have been synthesized by using a zeolitic imidazolate framework, ZIF-8, as self-sacrificing template. The initial derived carbon (D-carbon) contains a 3-dimensional (3D) hierarchically porous carbon framework with rich nitrogen doping (11.22%). Chemical activation by KOH, the further activated carbon (Ac-carbon) shows a specific high surface area (2477 m 2 g −1 ), but lower N content (1.99%). LiBH 4 -(D-carbon)/(Ac-carbon) is prepared by ball-milling method and the dehydrogenation performance of LiBH 4 is significantly improved. More than 6.13 wt% H 2 can be released from either of the two mixtures within 100 min at 320 °C, respectively, showing better dehydrogenation performance than that of pure LiBH 4 . Additionally, the controlled experiments reveal that those improved dehydrogenation properties of LiBH 4 might be attributed to the synergetic contributions of high N heteroatom loading, large surface area and catalysis of carbon materials. We provided a simple method to prepare solely MOF-derived nitrogen-doped carbon materials, which might be a promising catalyst for the hydrogen storage materials. [ABSTRACT FROM AUTHOR]

Step quenching and tempering (SQT) for HSLA multi-phases steel was designed to obtain the desirable multi-phases microstructure with the superior mechanical properties. Quenching and tempering (QT) and intercritical quenching and tempering (IQT) was also conducted as controls. Besides, Effects of austenitizing temperature for the different treatment routes on microstructural characteristics and mechanical properties were also investigated. Due to the cooperation of the “soft” ferrite/pearlite and “hard” martensite, the samples undergoing SQT possess the relatively high tensile strength and impact toughness, and the lowest yield ratio. Increase of austenitizing temperature results in the coarse austenite grains, and thus significantly decrease of tensile strength and impact energy, in spite of the heat treatment paths. Higher austenitizing temperature also leads to lower density of dislocations and higher grain size, which reduces the yield ratio for all samples. [ABSTRACT FROM AUTHOR]

Ubiquitination plays a very important role in the response to abiotic stresses of plant. To identify key regulators of salt stress, a gene GhSARP1 (Salt-Associated Ring finger Protein)encoding C3H2C3-type E3 ligase, was cloned from cotton. Transcription level of GhSARP1 was high in leaf, flower and fiber of 24,27 and 27DPA (Days Post-Anthesis), but low in root and stem. Except PEG6000 treatment, the expression of GhSARP1 was down-regulated by NaCl, cold and ABA after being treated for 1 h. GhSARP1-GFP fusion protein located on the plasma membrane, which was dependent on trans -membrane motif. In vitro ubiquitination assay showed that GhSARP1 had E3 ligase activity. Heterogeneous overexpression of GhSARP1 reduced salt tolerance of transgenic Arabidopsis in germination and post-germination stage. Our results suggested that the GhSARP1 might negatively regulate the response to salt stress mediated by the ubiquitination in cotton. [ABSTRACT FROM AUTHOR]

High performance Cu doped MgB 2 bulks were prepared by an in-situ method with carbon-coated amorphous boron as precursor. It was found that the usage of carbon-coated boron in present work leads to the formation of uniformly refined MgB 2 grains, as well as a high level of homogeneous carbon doping in the MgB 2 samples, which significantly enhance the J c in both Cu doped and undoped bulks compared to MgB 2 bulks with normal amorphous boron precursor. Moreover, minor Cu can service as activator, and thus facilitates the growth of MgB 2 grains and improves crystallinity and grain connectivity, which can bring about the excellent critical current density ( J c ) at self fields and low fields (the best values are 7 × 10 5 A/cm 2 at self fields, and 1 × 10 5 A/cm 2 at 2 T, 20 K, respectively). Simultaneously, minor Cu addition can reduce the amount of MgO impurity significantly, also contributing to the improvement of J c at low fields. Our work suggests that Cu-activated sintering combined with employment of carbon-coated amorphous boron as precursor could be a promising technique to produce practical MgB 2 bulks or wires with excellent J c on an industrial scale. [ABSTRACT FROM AUTHOR]

NAC (NAM, ATAF1/2, CUC2) transcription factors are plant-specific and have diverse functions in many plant developmental processes and responses to stress. In our previous study, we found that the expression of ATAF1, an Arabidopsis NAC gene, was obviously induced by high-salinity and abscisic acid (ABA). The overexpression of ATAF1 in Arabidopsis increased plant sensitivity to ABA and salt. To investigate whether ATAF1 affects the sensitivity of monocotyledon plant to salt and ABA, ATAF1 transgenic rice were generated. Transgenic rice exhibited significantly improved salt tolerance and insensitivity to ABA. The results of real-time PCR showed that ATAF1 overexpression in rice elevated the transcription of OsLEA3, OsSalT1 and OsPM1, which are stress-associated genes. Our results indicate that ATAF1 plays an important role in response to salt stress and may be utilized to improve the salt tolerance of rice. [ABSTRACT FROM AUTHOR]

As the “low activation” superconductor, Mg 11 B 2 has a potential application in superconducting coils for fusion reactor. In present work, the sintering process and critical current density of low activation Mg 11 B 2 superconductors were systemically studied from low temperature to high temperature. It was found that the J c and H irr values of Mg 11 B 2 bulks in present work are both obviously higher than that of those samples prepared in previous studies. Furthermore, the low-temperature sintered samples exhibit better J c performance at high fields than the high-temperature sintered samples, due to strong grain boundaries pinning. On the other hand, the high-temperature sintered samples have higher J c at low fields compared to low-temperature sintered samples, mainly owing to their better crystallinity and grain connectivity. The highest J c value (2.20 ×10 5 A cm −2 at 20 K, self-field) is obtained in the Mg 11 B 2 sample sintered at 850 °C for 45 min. [ABSTRACT FROM AUTHOR]

• The Bowen is a major factor in HMA's vegetation-climate feedback. • Areas of vegetation-driven T s decline are 64.22% (SIF) and 53.68% (NDVI). • The maximum vegetation activity-induced temperature change is −0.538 K. Satellite-driven and site observational data show that global warming has greatly enhanced vegetation activity (greening), with a broad upward trend in vegetation indices (VIs). However, the biophysical impact of vegetation on land surface temperature (T s) is widely unknown, particularly in High Mountain Asia (HMA). In this study, we assessed vegetation dynamics in HMA from 2000 to 2020 and used intrinsic biophysical mechanism (IBM) models to quantify the biophysical feedback effects of vegetation on T s. The results illustrate that, during the study period, HMA has undergone greening at a rate of 0.505 × 10−3 W m −2 μm−1 sr−1 yr−1 (solar-induced chlorophyll fluorescence: SIF) and 1.7 × 10−3 yr−1 (normalized vegetation index: NDVI), accounting for 52.75% and 47.24% of the total number of pixels, respectively. However, vegetation browning has occurred in areas such as the central Tien Shan and southeastern Tibet. Meanwhile, 64.22% (SIF) and 53.68% (NDVI) of the vegetation area in HMA showed a negative sensitivity of T s to vegetation activity, particularly herbaceous and scrub vegetation in Inner Tibet and eastern Kun Lun. Additionally, the Bovine ratio and aerodynamic drag (r a) exhibited a negative sensitivity to vegetation activity. Most importantly, the vegetation activity-induced temperature changes were -0.278 K (Δ T N D V I C I B M ) , -0.538 K (Δ T S I F C I B M ) , 0.028 K (Δ T N D V I S I B M ) , and 0.024 K (Δ T S I F S I B M ). Moreover, in the sensitivity method (Δ T V e g S I B M ) , vegetation cooling was detected in more than half of the pixels in HMA and was even more pronounced with SIF, accounting for 64.22% compared to 53.68% with NDVI. Enhanced vegetation activity alters the original balance of latent and sensible heat fluxes (Le , H) and increases the turbulent heat transfer between land and atmosphere, particularly L e. Our findings have important implications for understanding the response and feedback of vegetation dynamics to climate change in arid alpine regions. [ABSTRACT FROM AUTHOR]

• The model based on the characteristics of imaging omics and machine learning has high predictive efficiency for the prognosis of acute stroke after mechanical thrombectomy. • Minimum absolute contraction and selection operator regression model screened the best radiomics features. • Six features highly correlated with prognosis of acute stroke after mechanical thrombectomy. • The support vector machine classifier established a useful prediction model in stroke patients receiving mechanical thrombectomy. Some patients with mechanical thrombectomy will have a poor prognosis. This study establishes a model for predicting the prognosis after mechanical thrombectomy in acute stroke based on diffusion-weighted imaging (DWI) omics characteristics. A total of 260 stroke patients receiving mechanical thrombectomy in our hospital were randomly divided into a training set (n = 182) and a test set (n = 78) in a 7:3 ratio. The regions of interest (ROI) of the imaging features of the DWI infarct area were extracted, and the minimum absolute contraction and selection operator regression model were used to screen the best radiomics features. A support vector machine classifier established the prediction model of the prognosis after mechanical thrombectomy of acute stroke based on the selected features. The prediction efficiency of the model was evaluated by the receiver operating characteristic (ROC) curve. A total of 1936 radiomic features were extracted, and six features highly correlated with prognosis were screened after dimensionality reduction. Based on the DWI model, the ROC analysis showed that the area under the curve (AUC) for correct prediction in the training and test sets was 0.945 and 0.920, respectively. The model based on the characteristics of radiomics and machine learning has high predictive efficiency for the prognosis of acute stroke after mechanical thrombectomy, which can be used to guide personalized clinical treatment. [ABSTRACT FROM AUTHOR]

Sn addition improves bulk superconducting properties of FeSe 0.5 Te 0.5 with the increase of onset transition temperature and sharpens the transition width. The critical current density ( J c ) of Sn-added sample is about 7×10 3 A cm −2 in self field and maintains a stable value of 3×10 2 A cm −2 even beyond 60,000 Oe at 4.3 K, much higher than that of the Sn-free one. Phase compositions and morphology characterizations indicate that minor Sn addition facilitates the formation of the superconducting phase whose composition is closer to the ideal one, and suppresses the formation of Fe 7 Se 8 impurity and amorphous phase, which contribute to the improvement of J c . [ABSTRACT FROM AUTHOR]

Sintering temperature plays a vital role in the evolution of phase structure and microstructure in polycrystalline FeSe 0.5 Te 0.5 bulks fabricated by the two-step sintering method, and thus significantly influences their superconducting properties. Elevated sintering temperature (600–700 °C) at second step facilitates the substitution of Te into the superconducting phase, which leads to the increased lattice distortion and thus contributes to the enhancement of superconductivity (the value of T c reaches 15.6 K). At the same time, the accelerated growth of the superconducting grains and the improved homogeneity motivated by elevated sintering temperature serve as the main reason for the sharp superconducting transition. [ABSTRACT FROM AUTHOR]

In this work, 3D hierarchical flower-like MoS 2 spheres are successfully fabricated via a hydrothermal method followed by a heat treatment. The obtained product is composed of few-layered MoS 2 nanosheets with enlarged interlayer distance (ca. 0.66 nm) of the (002) plane. Meanwhile, the hydrogen storage properties of the as-prepared MoS 2 ball milled with LiBH 4 are systematically investigated. The results of temperature programmed desorption (TPD) and isothermal measurement suggest that the LiBH 4 –MoS 2 (as-prepared) mixture exhibits favorable dehydrogenation properties in both lowering the hydrogen release temperature and improving kinetics of hydrogen release rate. LiBH 4 –MoS 2 (as-prepared) sample (the preparation mass ratio is 1:1) starts to release hydrogen at 171 °C, and roughly 5.6 wt% hydrogen is released within 1 h when isothermally heated to 320 °C, which presents superior dehydrogenation performance compared to that of the bulk LiBH 4 . The excellent dehydrogenation performance of the LiBH 4 –MoS 2 (as-prepared) mixture may be attributed to the high active site density and enlarged interlayer distance of the MoS 2 nanosheets, 3D architectures and hierarchical structures. [ABSTRACT FROM AUTHOR]

The un-doped Mg 11 B 2 and Cu-doped Mg 11 B 2 bulks using 11 B as a boron precursor were fabricated by solid-state reaction and sintered at different temperature in present work. By analyzing the sintering process, it was found that 11 B original powder is more reactive and can react with Mg severely even at low temperature before Mg melting, which leads to the formation of refined Mg 11 B 2 grains. Consequently, the critical current density of Mg 11 B 2 sample prepared in this work is higher than that of natural MgB 2 . Furthermore, it was found that proper Cu addition could obviously accelerate the reaction between Mg and 11 B and promote the formation of Mg 11 B 2 due to the appearance of Mg–Cu liquid at low sintering temperature before Mg melting. On the other hand, Cu addition also introduced more MgCu 2 impurity, leading to a relatively lower critical current density on the whole. Interestingly, the critical current density of the Cu doped sample sintered at 800 °C is surprisingly enhanced at the low field, compared with that of the corresponding un-doped one. This is due to the peritectic reaction which generated small-sized MgCu 2 occurred that at 800 °C, providing MgCu 2 pinning centers well-distributed in the MgB 2 matrix. [ABSTRACT FROM AUTHOR]

Isochronal DSC measurements of various degrees cold-rolled Inconel 718 alloy samples were implemented to investigate the effect of cold rolling on the precipitation kinetics of intermediate phases in Inconel 718 alloy. The result shows that the values of the onset temperature ( T O n s e t 1 ) , the peak temperature ( T P e a k 1 ) and the end temperature ( T E n d 1 ) of γ″-phase precipitation decrease as the degree of cold rolling increases. In contrast, all values of the onset temperature ( T O n s e t 2 ) , the peak temperature ( T P e a k 2 ) and the end temperature ( T E n d 2 ) of δ-phase precipitation first increase and then decrease with the degree of cold rolling increasing as a consequence of a combined effect of lack of Nb atoms and recrystallization. Two sets of isothermal aging experiments were also carried out to study the effect of cold rolling on the morphology evolution of γ″-phase and δ-phase in Inconel 718 alloy. It is found that cold rolling promotes γ″→δ transformation and the morphology of γ″-phase turns more globular as the degree of cold rolling increases for the cold-rolled Inconel 718 alloy samples with isothermal aging at 800 °C for 8 h (procedure A). Moreover, for the cold-rolled Inconel 718 alloy samples with isothermal aging at 950 °C for 6 h (procedure B), cold rolling facilitates δ-phase precipitation and the δ-phase particles gradually sphericalized with increase in the degree of cold rolling. [ABSTRACT FROM AUTHOR]

Differential dilatometry was applied to investigate the effect of an applied constant uniaxial compressive stress on the kinetics of the austenite (γ) → martensite (α′) transformation in the substitutional Fe–0.7 at.%Al alloy upon isochronal cooling/quenching with constant rate. All imposed stress levels are below the yield stresses of γ and α′ phases in the temperature range of the martensite formation. Albeit the start temperature of the γ → α′ transformation remains approximately constant in the range of stress explored, the overall transformation temperature range increases significantly with the increase of the uniaxial compressive stress. A modular phase transformation model, adopting a model for continuous nucleation and an anisotropic thermally-activated growth model, yielding a corresponding impingement correction, was employed to extract the nucleation rate and the γ/α′-interface velocity during the transformation. The kinetic analysis suggests that athermal nucleation and thermally activated growth govern the martensite transformation under the uniaxial compressive stress. More driving force is required when a larger uniaxial compressive stress is imposed, and the thus obtained velocity of the γ/α′-interface as function of temperature indicates a thermally activated growth governed by a relatively low activation energy. [ABSTRACT FROM AUTHOR]

We report the synthesis and anode application for sodium-ion batteries (SIBs) of WS2 nanowires (WS2 NWs). WS2 NWs with very thin diameter of ≈25 nm and expanded interlayer spacing of 0.83 nm were prepared by using a facile solvothermal method followed by a heat treatment. The as-prepared WS2 NWs were evaluated as anode materials of SIBs in two potential windows of 0.01-2.5 V and 0.5-3 V. WS2 NWs displayed a remarkable capacity (605.3 mA h g−1 at 100 mA g−1) but with irreversible conversion reaction in the potential window of 0.01-2.5 V. In comparison, WS2 NWs showed a reversible intercalation mechanism in the potential window of 0.5-3 V, in which the nanowire-framework is well maintained. In the latter case, the interlayers of WS2 are gradually expanded and exfoliated during repeated charge-discharge cycling. This not only provides more active sites and open channels for the intercalation of Na+ but also facilitates the electronic and ionic diffusion. Therefore, WS2 NWs exhibited an ultra-long cycle life with high capacity and rate capability in the potential window of 0.5-3 V. This study shows that WS2 NWs are promising as the anode materials of room-temperature SIBs. [ABSTRACT FROM AUTHOR]