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The thermal problems closely related to the development of human life, scientific technology and engineering production are greatly influenced by the thermal properties of carrier media, while most traditional natural substances are incompetent to achieve the flexible and diverse on-demand thermal control that is increasingly needed. Stimulated by materials science and physics, the combination of thermal metamaterial (artificial composite with peculiar thermalphyscial properties) and transformation thermotics (theoretical method of pre-designing heat distribution at will) has promoted heat transfer research enter a novel phase. Aiming at macroscopic heat transfer that is one of the most fundamental cases in thermal science and directly affects various thermal management and thermal rectification problems, in this review, we retrace the progress of transformed thermal meta-devices for manipulating macroscopic thermal field from the various aspects combining theoretical calculation, numerical simulation and experimental verification. Apart from the devices containing single field manipulation function or applicable to single thermal field, we further take a look at multifunctional transformed thermal meta-devices including devices that suitable for different physical fields and containing various forms of thermal field manipulation. Moreover, we review the explorations of practical application of transformed thermal meta-devices. Finally, we point out some limitations and challenges together with potential future directions in this fascinating area.

• Proper pre-holding during quenching improves microstructural uniformity of GCr15 steel. • High uniformity of microstructure remarkably improves the toughness of GCr15 steel. • Proper pre-holding facilitates simultaneously nucleation and growth of austenite. • Austenite growth is correlated to carbides dissolution. In order to improve the uniformity of microstructures, and thus enhance the mechanical properties, especially the impact toughness, of 52100 bearing steels, modified quenching heat treatments with different austenitizing processes have been designed. The results show that 740 °C is the optimal holding temperature (approaching Ac 1 = 750 °C) to improve the impact toughness of the steel by 37% after quenching and low-temperature tempering. Microstructure observations reveal that 740 °C holding shortens the nucleation incubation period of austenitization phase transformation, and inhibits the overfast growth of austenite in some regions, which leads to simultaneous nucleation and growth of austenite during austenitizing, and homogeneous dissolution of carbides in different austenite grains. The changes in microstructure evolution improve the microstructure uniformity (carbide and grain size) after quenching. Uniformly distributed carbides and grain size effectively reduce stress concentration and retard crack propagation during impact loading, thus resulting in high impact toughness. [Display omitted] [ABSTRACT FROM AUTHOR]

Checkpoint inhibitors have been used with chemotherapy to improve antitumor efficacy. However, overcoming the immunosuppressive effect of chemotherapeutics remains a challenge. We report a nanobody–catalyst conjugate Ru-PD-L1 by fusing a ruthenium catalyst to an anti-PD-L1 nanobody. After administration of Ru-PD-L1 and a doxorubicin (DOX) prodrug, Ru-PD-L1 disrupts the PD-L1/PD-1 interaction and catalyzes the uncaging of the DOX prodrug. The spatially confined release of DOX reduces its systemic toxicity and leads to immunogenic cell death (ICD). The induced ICD triggers antitumor immune responses, which are further amplified by PD-L1 blockade to elicit synergistic chemo-immunotherapy, substantially increasing the number of tumor-infiltrating T-cells by 49.7% compared with the controls, thereby exhibiting high antitumor activity and low cytotoxicity in murine models. The combinational treatment could inhibit the growth of mice tumors by 67.7% compared to the control group. This combinational approach circumvents the negative immunogenic effects of chemotherapeutics and provides a potential chemo-immunotherapy strategy for human cancer treatment.

Two 15Cr–9Ni–Nb austenitic stainless steel weld metals with 2.5% Si and 3.5% Si (namely 2.5Si and 3.5Si samples, respectively) were designed and prepared through tungsten inert gas (TIG) welding and then hold at 800 °C or 900 °C for 3 h for stabilization. The microstructure and mechanical properties were investigated both for the as-welded and after-stabilization heat treatment (SHT) weld metals. There are 3.0–4.0% martensite and 2.5–3.5% δ ferrite in the 2.5Si as-welded weld metal and 6.0–7.0% δ ferrite in the 3.5Si as-welded weld metal. After SHT, a large amount of martensite formed in the 2.5Si weld metal, and δ → γ transition occurred during the SHT process both for the 2.5Si and 3.5Si weld metals. There were a large amount of coarse NbC and few nanoscale NbC in the as-welded weld metal. During the SHT, a large amount of nanoscale NbC formed in the matrix, while a large number of G phases formed at the austenite grain boundaries and the δ/γ interfaces. The decrease in solid solution C and δ ferrite content led to the decline of the yield strength of the weld metal after SHT. The martensite formed in 2.5Si weld metal after SHT had less effect on strength because of its low carbon content. The G phases formed during the SHT reduced the impact energy of the weld metal because it promoted the intergranular fracture, while the δ → γ transition reduced the amount of the δ/γ interfaces and avoided the intergranular fracture, which was beneficial for the impact toughness of the weld metals.

An electricity-promoted method for Friedel–Crafts acylation of biarylcarboxylic acids is described in this research. Various fluorenones can be accessed in up to 99% yields. During the acylation, electricity plays an essential role, which might motivate the chemical equilibrium by consuming the generated TFA. This study is predicted to provide an avenue to realize Friedel–Crafts acylation in a more environmentally friendly process.

Effective management of both near-infrared (NIR) radiation and long-wavelength infrared (LWIR) thermal emission through window design holds tremendous promise for achieving carbon neutrality in the building sector. Compared to the traditional static low emissivity (Low-E) and solar regulating windows, emerging emissivity-altering windows can better adapt to varied weather. However, dynamic windows with self-adaptive solar radiation and emissivity control have long been challenging, primarily due to the intricate broadband spectrum manipulation requiring sophisticated material design. Herein, by employing the NIR transparent hydrogen-doped In2O3(IHO) as a function layer (ε= 0.13, TNIR= 79.8 %), we present a broadband self-adaptive radiative thermal management (SRTM) window based on Fabry-Perot resonator. Compared to the common tin-indium oxide (ITO)-based counterpart, the IHO-based SRTM window shows a 70 % enhancement in NIR power regulation ability (10.9 %) with remaining emissivity regulation ability (0.26). It contributes significantly to energy conservation offering an annual energy saving and equivalent CO2emissions reduction of up to 20 % (411 MJ·m−2) and 244 tons/yr, compared to traditional Low-E windows globally.

A 16Cr-25Ni superaustenitic stainless steel weld metal for austenitic stainless steel/ferrite heat-resistance steel dissimilar metal weld was designed and prepared through tungsten inert-gas welding. The precipitate evolution and its correlation with mechanical properties were investigated during post-weld heat treatment (PWHT) at 690 °C for up to 12 h. The primary precipitates in the as-welded weld metal were identified as Mo-rich M6C carbides in the interdendritic region and semicontinuous fine-sized M23C6carbides along grain boundary. After PWHT, three types of precipitates coexisted in the interdendritic region: primary M6C carbides, newly precipitated Mo-rich M2Xcarbonitrides and some of the secondary M23C6carbides. Additionally, mass secondary M23C6carbides formed and coarsened along grain boundary. No undesirable intermetallic phases formed during the whole period. The M2Xand interdendritic M23C6improved the strength of the weld metal after PWHT, but the elongation and impact toughness degraded, which were mainly owing to the intergranular M23C6carbides that changed the fracture mode from ductile transgranular mode to mixed mode of transgranular and intergranular fracture. Meanwhile, the coarsening of M2Xcarbonitrides may lead to the elongation loss during 8 h to 12 h. Evolution of impact toughness was also related to the M2Xcarbonitrides, which made the crack easier to propagate compared with austenitic matrix and contributed to the decline of impact toughness. However, due to the sluggish precipitation of M2Xcarbonitrides with longer holding time, the decreasing trend became slow from 4 to 12 h. The results showed that PWHT should be controlled within 8 h to obtain better combination of strength and ductility.

• Stress relaxation cracking in Super304H austenitic stainless steel weld metal. • The pre-compressed CT technique combined with FEM analysis was successfully used. • The mechanism responsible for stress relaxation cracking formation was illustrated after short-term aging and long-term aging. The pre-compressed CT technique was used to quantitatively investigate the formation of stress relaxation cracks under different tensile residual stresses and aging time in Super304H austenitic stainless steel weld metal. The statistical results revealed that intergranular cracks could occur within 2000 h under 650 °C when the residual stress was applied with greater than 18 KN pre-compression force. Detailed grain interior and boundary analyses showed that the growth of intragranular Cu-rich particles could induce a strong grain interior, and the intergranular Nb(C, N) carbides were one of the causes to crack under short-term aging time. For long-term aging time conditions, the intergranular M 23 C 6 carbides were more susceptible to crack than intergranular Nb(C, N) carbides. Finally, the mechanism responsible for stress relaxation cracking formation was carefully illustrated for the weld metals after short-term aging and long-term aging, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

The resistance spot weldability of the newly developed TWIP1180 and Q&P980 with different thicknesses was evaluated. The different sheet thicknesses, heat conductivities and melting points caused that the Q&P/TWIP spot welds showed significantly asymmetric weld nuggets, and correspondingly influenced the tensile shear properties and failure modes of the spot welds. Pullout or partial pullout failure modes were obtained for the Q&P/Q&P and Q&P/TWIP combinations under proper welding currents, while only interfacial failure mode was observed for the TWIP/TWIP combination owing to the high strength and large thickness. Furthermore, the proper welding lobe for the Q&P/TWIP combination was obtained, which was crucial for the application of TWIP1180 and Q&P980 in automobile industry.

The resistance spot weldability of the newly developed TWIP1180 and Q&P980 with different thicknesses was evaluated. The different sheet thicknesses, heat conductivities and melting points caused that the Q&P/TWIP spot welds showed significantly asymmetric weld nuggets, and correspondingly influenced the tensile shear properties and failure modes of the spot welds. Pullout or partial pullout failure modes were obtained for the Q&P/Q&P and Q&P/TWIP combinations under proper welding currents, while only interfacial failure mode was observed for the TWIP/TWIP combination owing to the high strength and large thickness. Furthermore, the proper welding lobe for the Q&P/TWIP combination was obtained, which was crucial for the application of TWIP1180 and Q&P980 in automobile industry.

The microstructural evolution and mechanical properties of Super304H austenitic stainless steel weld metals with Nb-free and 1.0 % Nb-additive were investigated during 650 °C long-term aging. Massive nanoscale M23C6particles distributed in the interdendritic regions of the Nb-free weld metal while most of the M23C6formed and coarsened on the phase interface between the primary Nb(C, N) phase and matrix in the Nb-bearing weld metal. Nano-sized Cu-rich particles dispersed inside the grains in both weld metals. All of these nano-sized particles gradually coarsened over time. The Cu-rich particles with high distribution density and nanometer size affect the microhardness of both weld metals most during long-term aging. The addition of Nb could increase the microhardness in the relatively short aging time, while the effect of Nb-addition on the microhardness in long-term aging is insignificant.

• Surface roughness exhibits a significant effect on the interface bonding mechanism and mechanical properties of titanium alloy joints. • Fine recrystallization grains are formed at the bonding interface of rough surfaces, which is attributed to rotational dynamic recrystallization. • For the bonding interface of polished surfaces, the original interface exists in the form of straight interface grain boundaries without fine recrystallization grains under the same deformation conditions. • The bonding joints of rough surfaces show lower elongation compared with that of polished surfaces due to the formation of heterogeneous fine grains with low Schmid factor along the bonding interface of rough surfaces. The influence of surface roughness on the interfacial dynamic recrystallization kinetics and mechanical properties of Ti-6Al-3Nb-2Zr-1Mo hot-compression bonding joints was systematically investigated. It is found that for the bonding interface of rough surfaces, elongated fine grains are formed at the bonding interface due to shear deformation of the interfacial area. As the surface roughness increases, the proportion of elongated grains drastically decreases as they further reorient to form equiaxed grains along the bonding interface of rougher surfaces resulting from severe incompatible deformation of the interface area. Meanwhile, high-density geometrically necessary dislocations accumulate around the interfacial recrystallization area to accommodate the incompatible strain and lattice rotation. A rotational dynamic recrystallization mechanism is thereby proposed to rationalize the formation of fine interfacial recrystallization grains during bonding of rough surfaces. In contrast to that of rough surfaces, bonding interface of polished surfaces exists in the form of straight interface grain boundaries without fine grains under the same deformation conditions. While with the increase of deformation strain, small grain nuclei form along the bonding interface, which is associated with discontinuous dynamic recrystallization assisted by strain-induced boundary migration of interface grain boundaries. Moreover, the bonding joints of rough surfaces show lower elongation compared with that of polished surfaces. This is because the formation of heterogeneous fine grains with low Schmid factor along the bonding interface of rough surfaces, leading to worse compatible deformation capability and thereby poor ductility of bonding joints. [Display omitted] [ABSTRACT FROM AUTHOR]

Rare earth (RE) addition to steels to produce RE steels has been widely applied when aiming to improve steel properties. However, RE steels have exhibited extremely variable mechanical performances, which has become a bottleneck in the past few decades for their production, utilization and related study. Here in this work, we discovered that the property variation of RE steels stems from the presence of oxygen-based inclusions. We proposed a dual low-oxygen technology, and keeping low levels of oxygen content in steel melts and particularly in the raw RE materials, which have long been ignored, to achieve impressively stable and favourable RE effects. The fatigue life is greatly improved by only parts-per-million-level RE addition, with a 40-fold improvement for the tension–compression fatigue life and a 40% enhancement of the rolling contact fatigue life. We find that RE appears to act by lowering the carbon diffusion rate and by retarding ferrite nucleation at the austenite grain boundaries. Our study reveals that only under very low-oxygen conditions can RE perform a vital role in purifying, modifying and micro-alloying steels, to improve the performance of RE steels.

[Display omitted] • 14Cr ODS FeCrAl alloy is fabricated by a new powder forging technique. • Powder forging results in smaller oxide-particles, finer grains and more dislocation in ferritic matrix. • Oxide nanoparticles in ODS alloy are identified as orthorhombic YAlO 3 phase. • 14Cr ODS FeCrAl alloy exhibits excellent mechanical properties below 700 °C. • A slight decrease in USE and an increase in DBTT are cause by the slightly higher porosity produced by powder forging process. A simple powder forging process was presented herein to fabricate an Fe-14Cr-4.5Al-2W-0.4Ti-0.5Y 2 O 3 ODS FeCrAl alloy. The forged alloy exhibits a high density that exceeds 97 % of the theoretical density. The ODS alloy was investigated in terms of the residual porosity, morphology and phase structure of oxide nanoparticles, impact toughness and tensile properties. It was found that refined grains were obtained during powder forging. A residual porosity less than 1.1 % has no impact on the precipitation of oxide nanoparticles. The average diameter of the oxide particles is 7.99 nm, with a number density of 2.75 × 1022 m−3. Almost all of the oxides are identified as orthorhombic YAlO 3 particles. The refined grains and uniformly distributed oxide nanoparticles enable the alloy to show excellent mechanical strength and ductility below 700 °C, and enable the ductile-to-brittle transition temperature to be close to room temperature. However, a slight decrease in strength at 1000 °C and the Charpy upper shelf energy has been suggested to be due to the residual porosity. These results indicate that powder forging can be used as a promising technique for the fabrication of ODS alloys. [ABSTRACT FROM AUTHOR]

• The heterogeneous deformation behavior of austenite and ferrite in the duplex stainless steelwas multiscale analyzed. • The strain in austenite grains can extend into the adjacent ferrite grains. • The strain distribution in austenite is more homogeneous than that in ferrite due to various deformation behaviors. • The interaction between austenite and ferrite becomes more obvious after their yielding due to back and forward stress. The heterogeneous deformation behavior of austenite and ferrite in the 2205 duplex stainless steel was subjected to multiscale analysis based on the in situ synchrotron-based high energy X-ray diffraction, microscopic digital image correlation, electron backscatter diffraction, and transmission electron microscopy. It is found that the heterogeneous deformation triggers from the yielding of austenite. During this deformation stage, austenite experiences greater strain in the area near the phase boundaries because of the impeded function of the phase boundaries to dislocations. Owing to the relatively small difference in hardness between the constituent phases, the strain in austenite grains extends into the adjacent ferrite grains when entering into the ferrite yielding stage. In addition, the strain distribution of the austenite grains is more homogeneous than that of the ferrite grains because of the lower stacking fault energy of austenite, which results in a planar slip, and higher stacking fault energy in case of ferrite, causing cross slip. The interaction between austenite and ferrite becomes considerably obvious when the strain further increases after both constituent phases yielding because of the back stress and forward stress in austenite and ferrite, respectively, which are generated by the pile-up of the geometrically necessary dislocations. [ABSTRACT FROM AUTHOR]

The uneven dispersion of graphene in the resin matrix hinders its application in anticorrosion coatings. This study reports a new method where graphene oxide (GO) is coated on the surface of the poly(glycidyl methacrylate) (PGMA) microspheres to promote the dispersion of GO in epoxy resin (EP) to improve the anticorrosion performance of EP. GO-coated PGMA microspheres (PGMA@GO) were successfully fabricated by electrostatic interaction, which was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and zeta potential analysis. The scanning electron microscopy results showed that the PGMA microspheres were uniformly coated with GO, when the weight ratio of PGMA@GO was 1:2 (PGMA: GO). Electrochemical impedance spectroscopy and salt immersion experiments were performed to evaluate the corrosion resistance of the EP composite coatings. Comparing with pure EP and GO/EP coatings, the mechanical properties and anticorrosion properties of coatings were improved after adding PGMA@GO. When the addition amount of PGMA@GO (of 50 g EP) was 1.0 wt% and about 0.67 wt% GO was only needed, the PGMA@GO/EP composite coating possessed a high impedance of 5.68 × 108Ω cm2and a low breakpoint frequency of 0.39 Hz for 21-day immersion in 3.5 wt% NaCl solution. The anticorrosion mechanism of PGMA@GO/EP composite coating was also discussed.

Chicken growth traits are economically important, but the relevant genetic mechanisms have not yet been elucidated. Herein, we performed a genome-wide association study to identify the variants associated with growth traits. In total, 860 chickens from a Gushi-Anka F2resource population were phenotyped for 68 growth and carcass traits, and 768 samples were genotyped based on the genotyping-by-sequencing (GBS) method. Finally, 734 chickens and 321,314 SNPs remained after quality control and removal of the sex chromosomes, and these data were used to carry out a GWAS analysis. A total of 470 significant single-nucleotide polymorphisms (SNPs) for 43 of the 68 traits were detected and mapped on chromosomes (Chr) 1–6, -9, -10, -16, -18, -23, and -27. Of these, the significant SNPs in Chr1, -4, and -27 were found to be associated with more than 10 traits. Multiple traits shared significant SNPs, indicating that the same mutation in the region might have a large effect on multiple growth or carcass traits. Haplotype analysis revealed that SNPs within the candidate region of Chr1 presented a mosaic pattern. The significant SNPs and pathway enrichment analysis revealed that the MLNR, MED4, CAB39L, LDB2, and IGF2BP1genes could be putative candidate genes for growth and carcass traits. The findings of this study improve our understanding of the genetic mechanisms regulating chicken growth and carcass traits and provide a theoretical basis for chicken breeding programs.

Recently, rapid development of intelligent wearable electronic equipment has triggered great needs for flexible and lightweight portable energy storage systems. Here, we demonstrate a low-cost ($ 0.5 m-2) and low density carbonized facial tissue paper (FCP) for high-conductive NiCo2S4nanotubes assisted novel ultra-flexible solid-state supercapacitors (SSCs). The hydrothermal synthesized FCP-900@NiCo2S4electrodes in this paper only have a density of 5 mg cm−2and show large specific capacitance of 3115 mF cm−2at 2 mA cm−2. Based on the high performance of FCP-900@NiCo2S4electrodes, the as assembled SSCs can deliver an energy density of 1.2 mWh cm−3, high power density of 58.16 mW cm−3. It also shows great bending-state capacitive performance with high capacitance retention after 5000 cycles, providing a new opportunity for developing high-performance flexible wearable energy storage devices.

ABSTRACTPolyaniline/graphene oxide (GON-An) composites were synthesized by chemically grafting p-phenylenediamine (PPDA)-modified graphene oxide (GO) with polyaniline (PANI), which was confirmed by FT-IR, XRD, SEM, TEM, Raman spectroscopy, and XPS analyses. The electrochemical impedance spectroscopy test, brine immersion, and Tafel slopes analysis revealed that compared with GO and PPDA-modified GO (GON), GON-An composites which combined the unique corrosion resistance of both PANI and GO exhibited relatively obvious superiority in improving the corrosion resistance of epoxy coating with the same contents. After being immersed in brine for 35 days, the composite epoxy coating containing 1 wt-% of GON-An(1:2) composites in which the mass ratio of GO and PANI was 1:2, possessed a high impedance of 4×109 Ω cm2, a high corrosion potential of −0.25 V, and a low corrosion current of 4.119×10−11 A cm−2. Furthermore, the anti-corrosive mechanisms of PANI/GO epoxy coatings were discussed.

A new, non-contact, three-dimensional (3D) bullet signature measuring system based on a chromatic confocal sensor is developed. The system is composed of a precision rotary table and a chromatic confocal sensor. The measurement uncertainty of the system is less than 1 µm. When measuring the surface topography of the object, the sensor acquires wavelength information reflected from the object instead of intensity information. This advantage is very suitable to bullet signature measurements. The chromatic confocal sensor works in the point measuring mode and can acquire data continuously with high speed. One round section measurement on the bullet body takes less than 1 minute.

Polyaniline/graphene oxide (GON-An) composites were synthesized by chemically grafting p-phenylenediamine (PPDA)-modified graphene oxide (GO) with polyaniline (PANI), which was confirmed by FT-IR, XRD, SEM, TEM, Raman spectroscopy, and XPS analyses. The electrochemical impedance spectroscopy test, brine immersion, and Tafel slopes analysis revealed that compared with GO and PPDA-modified GO (GON), GON-An composites which combined the unique corrosion resistance of both PANI and GO exhibited relatively obvious superiority in improving the corrosion resistance of epoxy coating with the same contents. After being immersed in brine for 35 days, the composite epoxy coating containing 1 wt-% of GON-An(1:2) composites in which the mass ratio of GO and PANI was 1:2, possessed a high impedance of 4×109O cm2, a high corrosion potential of -0.25 V, and a low corrosion current of 4.119×10-11A cm-2. Furthermore, the anti-corrosive mechanisms of PANI/GO epoxy coatings were discussed.

We synthesized a mesoporous film based on TiO2–reduced graphene oxide (RGO) hybrids using a one-step vapor-thermal method without the need for an additional annealing process. The vapor-thermally prepared TiO2-graphene hybrid (VTH) features unique structures with an ultra-large specific surface area of ˜260 m2g−1and low aggregation, giving rise to enhanced light harvesting and increased charge generation and separation efficiency. It was observed that a mesoporous film with uniform pore distribution is simultaneously obtained during the VTH growth process. When a 5.0 wt% RGO VTH film was used as the active layer in photocatalysis, the highest photocatalytic activity for degradation of methyl orange was achieved. For another, when a 0.75 wt% RGO VTH film was used as the photoanode in a dye-sensitized solar cell, the power conversion efficiency reached 7.58%, which represents an increase of 73.1% compared to a solar cell using an a photoanode of pure TiO2synthesized by a traditional solvothermal method. It is expected that this facile method for the synthesis of TiO2/graphene hybrid mesoporous films will be useful in practical applications for preparing other metal oxide/graphene hybrids with ultra-high photocatalytic activity and photovoltaic performance.

The effects of rare earth (RE) on the microstructure and impact toughness of low alloy Cr-Mo-V bainitic steels have been investigated where the steels have RE content of 0 to 0.048 wt.%. The results indicate that the normalized microstructures of the steels are typical granular bainite (GB) composed primarily of bainitic ferrite and martensite and/or austenite (M-A) constituents. The M-A constituents are transformed into ferrite and carbides and/or agglomerated carbides after tempering at 700 °C for 4 h. The addition of RE decreases the onset temperature of bainitic transformation and results in the formation of finer bainitic ferrite, and reduces the amount of carbon-rich M-A constituents. For the normalized and tempered samples, the ductile-to-brittle transition temperature (DBTT) decreases with increasing RE content to a critical value of 0.012 wt.%. Lower DBTT and higher upper shelf energy are attributed to the decreased effective grain size and lower amount of coarse agglomerated carbides from the decomposition of massive M-A constituents. However, the addition of RE in excess of 0.012 wt.% leads to a substantial increase in the volume fraction of large-sized inclusions, which are extremely detrimental to the impact toughness. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries are highly attractive for their theoretical energy density and natural abundance, but the drawbacks of low sulfur utilization and rapid capacity fade in high-sulfur-loading cathodes still retard their practical use. To enhance kinetics in high-sulfur-loading Li–S cells, it is important to first understand and control the deposition of Li2S/Li2S from highly soluble lithium polysulfide (LiPS) during discharge processes. Here, we presented a series of multiphase-derived self-standing papers with diverse electronic conductivity and LiPS affinity for highly concentrated LiPS discharge processes and explained the Li2S/Li2S deposition behavior in detail. We demonstrated that high rate capacity and long cycle life of as-assembled paper–LiPS cathodes can be greatly depended on their phase material with high conductivity and LiPS affinity. A high-performance self-standing LiPS host–multiwalled carbon nanotube (MWCNT)/cellulose nanofiber (CNF)/NiCo2S4(3.5 mg cm–2) can catalyze 2.85 mg cm–2(based on sulfur) loaded LiPS to deliver a high specific capacity of 1154 mAh g–1at 0.1C and a high rate performance of 963 mAh g–1at 1C. We suggest that the insulating phase defect of nano-CNF and both highly electronic conductive (above 50 S cm–1) and LiPS adsorptive NiCo2S4can promote the local concentration effect of LiPS, thus contributing to fast and stable heterogeneous particle-shaped deposition of Li2S2/Li2S and leading to high kinetics of the LiPS cathode.

The realization of room-temperature preparation of the perovskite solar cells without a thermal annealing step could simplify the fabrication process and reduce the energy consumption. N,N-Dimethylacetamide (DMAc) is a promising candidate to replace N,N-dimethylformamide (DMF) as a perovskite precursor solvent with the advantage of room-temperature processability, while the influencing mechanism of DMAc and DMF solvents on controlling nucleation and crystallization kinetics has received limited attention. In light of this, we investigate the morphological structure and spectral properties of the perovskite films and verify the successful fabrication of high-quality α-phase perovskites from DMAc at room temperature. Further infrared and Raman spectroscopy reveals that the weakened interaction between DMAc and solutes helps perovskites to rapidly nucleate and crystallize from the solvent, promoting complete phase transformation to form a perovskite film. In situ UV–vis spectroscopy demonstrates the solvent effect on the crystallization kinetic process during film drying at room temperature. This work provides valuable insights into the preparation of high-quality perovskite films at room temperature, thereby driving the production of cost-effective perovskite devices.

High-carbon chromium bearing steels with different rare earth (RE) contents were prepared to investigate the effects of RE on inclusions and impact toughness by different techniques. The results showed that RE addition could modify irregular Al 2 O 3 and MnS into regular RE inclusions. With the increase of RE content, the reaction sequence of RE and potential inclusion forming elements should be O, S, As, P and C successively. RE inclusions containing C might precipitate in molten steel and solid state, but the precipitation temperature was significantly higher than that of carbides in high-carbon chromium bearing steel. For experimental bearing steels, the volume fraction of inclusions increased steadily with the increase of RE content, but smaller and more dispersed inclusions could be obtained by 0.018% RE content compared with bearing steel without RE, whereas the continuous increase of RE content led to an increasing trend for inclusion size and a gradual deterioration for inclusion distribution. RE addition could improve the transverse impact toughness and isotropy of bearing steel, and for modified high-carbon chromium bearing steel by RE alloying, the increase of RE content continuously increased both transverse and longitudinal impact toughness until excessive RE addition. [ABSTRACT FROM AUTHOR]

The effects of different double ageing processes on the mechanical properties and microstructural evolution in the 1460 alloy were investigated. The corresponding microstructure and mechanical properties of the heat-treated specimens were studied by means of transmission electron microscopy, differential scanning calorimetry, hardness testing and tensile testing. The results show that the elongation of two-step aged (130 °C/84 h + 160 °C/24 h) samples can be increased to 8 % with a minor decrease in tensile strength (450 MPa). Throughout the two-step ageing process, the precipitation behaviour of the alloy exhibited the following characteristics: the δ′ phase formed at lower temperature dissolved into the matrix instead of coarsening and becoming over-aged at the beginning of the second ageing step; finely distributed θ′(Al2Cu) and δ′(Al3Li) at a steady state were obtained, resulting in a significant improvement in tensile strength; and the peak ductility occurred with the precipitation of T1(Al2CuLi) and consumption of δ′(Al3Li), as small δ′ particles caused a co-planar slip, resulting in lower ductility.

Abstract The microstructure evolutions and the mechanical properties of the 25Cr-20Ni austenitic stainless steel weld metals with different Nb contents were investigated during the long term aging treatment at 700 °C. M 23 C 6 , Nb(C, N), α-Cr phase and Nb-nitride phase (Z phase) were observed in the microstructures of the aged weld metals. The results showed that the α-Cr phase precipitated in the interdendritic regions of the weld metals after being exposed to 700 °C for 500 h and the element Nb accelerated the precipitation of the α-Cr phase significantly. The density of the α-Cr phase decreased with the increase of the distance away from the primary Nb(C, N). Additionally, the α-Cr phase showed a crystallographic relationship with the austenitic matrix, [ 1 1 ¯ 1 ¯ ] α-Cr // [ 1 1 ¯ 0 ] γ and (01 1 ¯) α-Cr // (1 ¯ 1 ¯ 1) γ. It was observed that the Z phase precipitated in the periphery of the Nb(C, N) and may replace the Nb(C, N) after long term exposure to high temperature. The transformation of the Nb(C, N) into Z phase suggested that the Z phase had a higher stability than the Nb(C, N) particles at 700 °C for long term aging. The tensile strength of the Nb-bearing weld metal showed a continuous decrease at the initial stage of the aging treatment and then went up slightly with the prolonged aging time. However, the elongations and the impact energies of the weld metals decreased monotonously with the increase of the aging time. [ABSTRACT FROM AUTHOR]

Here, we report the leading manufacture of the large-scale integral weldless stainless steel forging ring (φ = 15.6 m) by the multilayer additive hot-compression bonding technology. Moreover, the detailed interface healing mechanism involving interfacial oxide evolution is elucidated, which validates the feasibility and reliability of the technique we proposed. [ABSTRACT FROM AUTHOR]

Because atoms in high-entropy alloys (HEAs) coordinate in very different and distorted local environments in the lattice sites, even for the same type of constituent, their point defects could highly vary. Therefore, theoretical determination of the thermodynamic quantities (i.e., defect formation enthalpies) of various point defects is rather challenging because each corresponding thermodynamic quantity of all involve constituents is not unique. The knowledge of these thermodynamic quantities is prerequisite for designing novel HEAs and understanding the mechanical and physical behaviors of HEAs. However, to date there has not been a good method to theoretically derive the defect formation enthalpies of HEAs. Here, using first-principles calculations within the density functional theory (DFT) in combination of special quasi-random structure models (SQSs), we have developed a general method to derive corresponding formation enthalpies of point defects in HEAs, using vacancy formation enthalpies of a four-component equiatomic fcc-type FeCoCrNi HEA as prototypical and benchmark examples. In difference from traditional ordered alloys, the vacancy formation enthalpies of FeCoCrNi HEA vary in a highly wide range from 0.72 to 2.89 eV for Fe, 0.88–2.90 eV for Co, 0.78–3.09 eV for Cr, and 0.91–2.95 eV for Ni due to high-level site-to-site lattice distortions and compositional complexities. On average, the vacancy formation enthalpies of 1.58 eV for Fe, 1.61 eV for Cr, 1.70 eV for Co and 1.89 eV for Ni are all larger than that (1.41 eV) of pure fcc nickel. This fact implies that the vacancies are much more difficult to be created than in nickel, indicating a reasonable agreement with the recent experimental observation that FeCoCrNi exhibits two orders of amplitudes enhancement of radiation tolerance with the suppression of void formation at elevated temperatures than in pure nickel. [ABSTRACT FROM AUTHOR]

Topological nodal line (DNL) semimetals, a closed loop of the inverted bands in its bulk phases, result in the almost flat drumhead-like non-trivial surface states (DNSSs) with an unusually high electronic density near the Fermi level. High catalytic active sites generally associated with high electronic densities around the Fermi level, high carrier mobility and a close-to-zero free energy of the adsorbed state of hydrogen (ΔGH*≈0) are prerequisite to design alternative of precious platinum for catalyzing electrochemical hydrogen production from water. By combining these two aspects, it is natural to consider if the DNLs are a good candidate for the hydrogen evolution reaction (HER) or not because its DNSSs provide a robust platform to activate chemical reactions. Here, through first-principles calculations we reported a new DNL TiSi-type family, exhibiting a closed Dirac nodal line due to the linear band crossings in ky=0 plane. The hydrogen adsorbed state on the surface yields ΔGH*to be almost zero and the topological charge carries participate in HER. The results highlight a new routine to design topological quantum catalyst utilizing the topological DNL-induced surface bands as active sites, rather than edge sites-, vacancy-, dopant-, strain-, or heterostructure-created active sites. 拓扑节线半金属具有体能带反转形成的闭合环状狄拉克节线. 体狄拉克节线投影到某些表面会形成闭合的圈, 圈内会出现受拓扑保护的能量色散非常小的鼓膜状表面态, 导致在费米能级具有高的电子密度. 目前, 为寻求贵金属铂的替代物, 新的析氢反应催化剂需要具有高电子密度的催化活性位置, 高的载流子移动性和恰当的热力学稳定性(ΔG≈0). 由鉴于此, 我们考虑具有稳定拓扑非平庸表面态的狄拉克节线半金属是否可以作为析氢催化的平台. 基于第一性原理计算, 我们提出TiSi型拓扑节线态半金属新家族. 在其倒空间ky=0面, 反转的两条能带相交形成闭合的狄拉克节线环. 氢吸附过程计算表明, 拓扑狄拉克节线完整投影的(010)表面氢吸附自由能ΔG几乎为0. 并且,拓扑电荷载流子也参与到了析氢过程. 综上, 我们提出拓扑狄拉克节线系统可以利用其鼓膜类拓扑表面态作为拓扑量子催化的平台, 并认为TiSi家族材料有望成为析氢反应的催化剂, 这种催化设计路线主要利用拓扑节线材料非平庸鼓膜类表面态作为催化活性位置, 与以往传统通过缺陷、界面修饰和构筑等调控催化剂存在本质不同.

In this study, we investigated the characteristics and herbicidal potential of bispyribac phenolic esters, which belong to the 2-(pyrimidin-2-yloxy)benzoic acid (PYB) class of acetohydroxyacid synthase (AHAS-)-inhibiting herbicides. These herbicides are primarily used for controlling Poaceae and broadleaf weeds. Among them, bispyribac-sodium stands out as a representative in this class. Surprisingly, other bispyribac esters, including alkanol and phenol esters exhibit considerably reduced herbicidal activity compared to bispyribac-sodium. In contrast, oxime esters (e.g., pyribenzoxim) demonstrate high activity. To further understand and develop novel PYB herbicides, we synthesized and screened a series of bispyribac phenolic esters while investigating their photochemical behaviors. Several compounds displayed excellent herbicidal activity, with compounds Ia-19and Icshowing impressive 90% effective dosages for fresh weight inhibition of barnyard grass, measuring 0.55 and 0.60 g a.i./hm2, respectively. These values were approximately half of bispyribac-sodium or pyribenzoxim. The results indicate that the herbicidal activity of phenolic esters is influenced by both their binding ability to the AHAS enzyme and their decomposition into bispyribac acid. For instance, bispyribac phenol ester exhibited considerably reduced receptor affinity compared to bispyribac-sodium, and faced challenges in transforming into bispyribac acid, explaining its diminished herbicidal activity. However, introducing a photosensitive nitro group led to a complete transformation. This modification improved its affinity with AHAS and accelerated its decomposition into bispyribac acid, further accelerated by photocatalysis. Consequently, nitro-containing compounds displayed heightened herbicidal activity. The findings from this study open possibilities for structural optimization of phenolic esters through quantitative structure–activity relationship analysis, potentially regulating their activity-releasing period. Furthermore, the high activity of aromatic heterocyclic esters offers new insights into developing novel PYB herbicides.

Cation composition engineering of perovskite polycrystals, such as substituting the typically used methylamine (MA+) with formamidine (FA+) wholly or partially, is a reliable protocol for fabricating high-efficiency perovskite solar cells (PSCs). Hitherto, it is still in debate how and to what extent the FA+substitution influences the ion migration, which restricts the further optimization of PSCs. In this work, ion migration kinetics in MAPbI3-based and FAPbI3-based PSCs was systematically studied by a series of time-resolved photoelectric measurements. We find that by replacing MA+with FA+, owing to the steric effect of the large-sized FA+, the cation migration is significantly suppressed, and the migration rate of halide anions is reduced. However, FA+results in a structural tolerance factor exceeding the ideal range, which leads to a drastic increase in halide defects and eventually aggravates the ion migration in FAPbI3PSCs. These findings provide unique insights into the manipulation of ion migration in PSCs via the strategy of cation composition engineering.

Defect passivation plays a critical role in manufacturing high-performance perovskite solar cells (PSCs). Herein, engineered components of metformin halides are introduced to the bulk and surface of perovskite layers in PSCs to realize synergistic defect passivation. It is found that the bulk addition of metformin hydrochloride influences the orientation distribution of perovskite crystals and contributes to better perovskite films. Further, the modification of metformin iodide could treat residual defects on the surface of perovskite films. As a result, the synergistically passivated PSCs shows an improved power conversion efficiency (PCE), which increased from 19.36% to 22.17%, together with a higher short-circuit current and open-circuit voltage than those of the control device. Moreover, the as-treated PSCs exhibit excellent thermal and humidity stabilities, maintaining 95% of their initial PCE after being stored under air conditions for over 1000 h. This work provides a novel strategy to passivate perovskite defects and improve the PCE and stability of PSCs.

The site preferences, fast and huge anisotropic diffusion mechanisms of Cu (Ag) in β –Sn as well as their reduction on the self-diffusivity of Sn, have been investigated using the first-principles and ab initio molecular dynamics methods. We have found that Cu prefers the interstitial site, whereas Ag is preferable in the substitutional site, which is mostly dominated by their different size factors. Electronic structure further evidences that the d – s hybridization between the solute and the host atom also contributes to the site preferences. It is also deduced that the fast diffusion of Cu (Ag) is mostly due to the interstitial diffusion mechanism and their diffusivity can be correlated with the amount of their respective interstitial solution. Their faster diffusion along the c -axis can be attributed to the extremely low migration energy barrier caused by the straight tunnel of considerable size with the screw axis symmetry of 2π/4 along the c -axis. Furthermore, it is found that during the process of diffusion the interstitially dissolved Cu (Ag) atoms would combine with the nearby Sn-vacancy and further annihilate the vacancy, thereby reducing the self-diffusion of Sn. [ABSTRACT FROM AUTHOR]