•Disordered BCC phase in Al0.9–Al1.0 alloys transforms into FCC and σ phases at 873K.•FCC and σ phases form in an associated manner from the Fe,Cr-rich BCC phase.•The σ phase connected with the FCC ...phase are formed from disordered BCC phase.•The TT range of the Alx alloys is at 810–930K which is about 0.5Tm of the alloys.•The Alx alloys with x⩾0.5 is slip below the TT and creep deformation above the TT.
The Alx–Co–Cr–Fe–Ni high-entropy alloy system (x=0–1.8 in molar ratio) was prepared by vacuum arc melting and casting method. Variations of temperature on crystal structure, microstructure and mechanical properties were investigated. The evolution of structure with temperature can be classified into four types: Al0–Al0.3: FCC structure; Al0.5–Al0.7: mixed structure (FCC+spinodal A2+B2)→FCC+B2 structure; Al0.9–Al1.2: spinodal A2+B2 structure (<873K)→FCC+σ+B2 structure (⩾873K)→FCC+B2 structure (⩾1235K); and Al1.5–Al1.8: spinodal A2+B2 structure→B2 structure. The hot hardness transition temperature (TT) range of this alloy system was at 810–930K. The Al0.5 alloy exhibited the highest TT/Tm value. Above TT, the Al0 and Al0.3 alloys possessed the highest softening coefficient and the Al0.9 and Al1.0 alloys exhibited the maximum softening coefficient amongst the Alx alloys. Differences of constituent phases, phase distribution and morphology could account for the softening difference. The mechanism for high softening resistance was also discussed.
Lithium‐ion capacitors (LICs) are a game‐changer for high‐performance electrochemical energy storage technologies. Despite the many recent reviews on the materials development for LICs, the design ...principles for the LICs configuration, the possible development roadmap from academy to industry has not been adequately discussed. Systematic understanding of device development is the foundation to more efficient utilization of advanced LICs materials. This review focuses on the principle of the recent configurations of LICs, the device design rationales, and new prelithiation techniques that are an integral part in LIC design. The authors also comment on the new generation multifunctional LICs that are capable of meeting the emerging applications in flexible electronics and other modern technologies. Finally, the status of LICs is presented and several key take‐home messages about minimizing the gaps between academic and industry requirements are proposed.
Lithium‐ion capacitors (LICs) are powerful competitors to supercapacitors and batteries due to their high energy‐power performance and long lifespan. The design rationale and device configuration of LICs are introduced, followed by the prelithiation methods and fabrication of multifunctional LICs. Finally, the status of commercial LICs and a possible roadmap of advanced LICs from laboratory to industry are discussed.
Abstract
We report the observations of FRB 20220912A using the Five-hundred-meter Aperture Spherical radio Telescope. We conducted 17 observations totaling 8.67 hr and detected a total of 1076 bursts ...with an event rate up to 390 hr
−1
. The cumulative energy distribution can be well described using a broken power-law function with the lower- and higher-energy slopes of −0.38 ± 0.02 and −2.07 ± 0.07, respectively. We also report the
L
-band (1–1.5 GHz) spectral index of the synthetic spectrum of FRB 20220912A bursts, which is −2.6 ± 0.21. The average rotation measure value of the bursts from FRB 20220912A is −0.08 ± 5.39 rad m
−2
, close to 0 rad m
−2
and was relatively stable over 2 months. Most bursts have nearly 100% linear polarization. About 45% of the bursts have circular polarization with Signal-to-Noise ratio > 3, and the highest circular polarization degree can reach 70%. Our observations suggest that FRB 20220912A is located in a relatively clean local environment with complex circular polarization characteristics. These various behaviors imply that the mechanism of circular polarization of FRBs likely originates from an intrinsic radiation mechanism, such as coherent curvature radiation or inverse Compton scattering inside the magnetosphere of the FRB engine source (e.g., a magnetar).
Biomass-derived jet (bio-jet) fuel has become a key element in the aviation industry׳s strategy to reduce operating costs and environmental impacts. Researchers from the oil-refining industry, the ...aviation industry, government, biofuel companies, agricultural organizations, and academia are working toward developing a commercially viable and sustainable process that produces a long-lasting renewable jet fuel with low production costs and low greenhouse emissions. This jet fuel, additionally, must meet ASTM International specifications and potentially be a 100% drop-in replacement for current petroleum jet fuel. In this study, the current technologies for producing renewable jet fuels, categorized by alcohols-to-jet, oil-to-jet, syngas-to-jet, and sugar-to-jet pathways are reviewed. The main challenges for each technology pathway, including conceptual process design, process economics and life-cycle assessment of greenhouse gas emissions are discussed. Although the feedstock price and availability and energy intensity of the process are significant barriers, biomass-derived jet fuel has the potential to replace a significant portion of conventional jet fuel required to meet commercial and military demand.
The crystallization problem is an outstanding challenge in the chemistry of porous covalent organic frameworks (COFs). Their structural characterization has been limited to modeling and solutions ...based on powder x-ray or electron diffraction data. Single crystals of COFs amenable to x-ray diffraction characterization have not been reported. Here, we developed a general procedure to grow large single crystals of three-dimensional imine-based COFs (COF-300, hydrated form of COF-300, COF-303, LZU-79, and LZU-111). The high quality of the crystals allowed collection of single-crystal x-ray diffraction data of up to 0.83-angstrom resolution, leading to unambiguous solution and precise anisotropic refinement. Characteristics such as degree of interpenetration, arrangement of water guests, the reversed imine connectivity, linker disorder, and uncommon topology were deciphered with atomic precision-aspects impossible to determine without single crystals.
Pathogen recognition by nucleotide-binding (NB), leucine-rich repeat (LRR) receptors (NLRs) plays roles in plant immunity. The
pv.
effector AvrAC uridylylates the
PBL2 kinase, and the latter (PBL2
) ...acts as a ligand to activate the NLR ZAR1 precomplexed with the RKS1 pseudokinase. Here we report the cryo-electron microscopy structures of ZAR1-RKS1 and ZAR1-RKS1-PBL2
in an inactive and intermediate state, respectively. The ZAR1
domain, compared with animal NLR
domains, is differently positioned to sequester ZAR1 in an inactive state. Recognition of PBL2
is exclusively through RKS1, which interacts with ZAR1
PBL2
binding stabilizes the RKS1 activation segment, which sterically blocks ZAR1 adenosine diphosphate (ADP) binding. This engenders a more flexible NB domain without conformational changes in the other ZAR1 domains. Our study provides a structural template for understanding plant NLRs.
Background： Nontraumatic osteonecrosis of the femoral head （NONFH） is a debilitating disease that represents a significant financial burden for both individuals and healthcare systems. Despite its ...significance, however, its prevalence in the Chinese general population remains unknown. This study aimed to investigate the prevalence of NONFH and its associated risk factors in the Chinese population. Methods： A nationally representative survey of 30,030 respondents was undertaken from June 2012 to August 2013. All participants underwent a questionnaire investigation, physical examination of hip, and bilateral hip joint X-ray and/or magnetic resonance imaging exalnination. Blood samples were taken after overnight fasting to test serum total cholesterol, triglyceride, and high-density lipoprotein （HDL） and low-density lipoprotein （LDL） levels. We then used multivariate logistic regression analysis to investigate the associations between various metabolic, demographic, and lifestyle-related variables and NONFH. Results： NONFH was diagnosed in 218 subjects （0.725%） and the estimated NONFH cases were 8.12 million among Chinesepeople aged 15 years and over. The prevalence of NONFH was significantly higher in males than in females （1.02% vs. 0.51%, x^2 = 24.997, P 〈 0.001 ）. Among NONFH patients, North residents were subjected to higher prevalence of NONFH than that of South residents （0.85% vs. 0.61%,x^2= 5.847, P = 0.016）. Our multivariate regression analysis showed that high blood levels oftriglycerides, total cholesterol, LDL-cholesterol, and non-H DL-cholesterol, male, urban residence, family history of osteonecrosis of the femoral head. heavy smoking, alcohol abuse and glucocorticoid intake, overweight, and obesity were all significantly associated with an increased risk of NONFH. Conclusions： Our findings highlight that NONFH is a significantpublic health challenge in China and underscore the need for policy measures on the national level. Furthermore, NONFH shares a number of risk factors with atherosclerosis.
The current outbreak of viral pneumonia in the city of Wuhan, China, was caused by a novel coronavirus designated 2019‐nCoV by the World Health Organization, as determined by sequencing the viral RNA ...genome. Many initial patients were exposed to wildlife animals at the Huanan seafood wholesale market, where poultry, snake, bats, and other farm animals were also sold. To investigate possible virus reservoir, we have carried out comprehensive sequence analysis and comparison in conjunction with relative synonymous codon usage (RSCU) bias among different animal species based on the 2019‐nCoV sequence. Results obtained from our analyses suggest that the 2019‐nCoV may appear to be a recombinant virus between the bat coronavirus and an origin‐unknown coronavirus. The recombination may occurred within the viral spike glycoprotein, which recognizes a cell surface receptor. Additionally, our findings suggest that 2019‐nCoV has most similar genetic information with bat coronovirus and most similar codon usage bias with snake. Taken together, our results suggest that homologous recombination may occur and contribute to the 2019‐nCoV cross‐species transmission.
Research Highlights
Taken together, our results suggest that homologous recombination may occur and contribute to the 2019‐nCoV cross‐species transmission.
It is common that different crystal facets in metal and metal oxide nanocrystals display different catalytic performances, whereas such phenomena have been rarely documented in metal–organic ...frameworks (MOFs). Herein, we demonstrate for the first time that a nickel metal–organic layer (MOL) exposing rich (100) crystal facets (Ni‐MOL‐100) shows a much higher photocatalytic CO2‐to‐CO activity than the one exposing rich (010) crystal facets (Ni‐MOL‐010) and its bulky counterpart (bulky Ni‐MOF), with a catalytic activity up to 2.5 and 4.6 times more active than Ni‐MOL‐010 and bulky Ni‐MOF, respectively. Theoretical studies reveal that the two coordinatively unsaturated NiII ions with a close distance of 3.50 Å on the surface of Ni‐MOL‐100 enables synergistic catalysis, leading to more favorable energetics in CO2 reduction than that of Ni‐MOL‐010.
Crystal‐facet‐dependent catalytic performance for CO2 reduction has been observed in Ni‐based 2D MOLs. Ni‐MOL‐100 displays much higher catalytic activity than Ni‐MOL‐010, benefiting from the synergistic catalysis between two adjacent Ni sites in Ni‐MOL‐100.
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