The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat...The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat-shrinkable tubing,as a seal on the rock surface,is crucial for reconstructing deep rock in situ conditions(ensuring the accuracy and effectiveness of confining pressure and pore pressure).However,there are few reports on testing such material under HTUP condition.Thus,the mechanical and sealing performances of existing heat-shrinkable tubing under HTUP condition is still immature.The motivation of this study is to advance deep rock mechanics and engineering by developing a polymer heat-shrinkable tubing(pressure larger than 140 MPa and temperature greater than 150℃).Experiments using the deep rock in situ thermal insulation coring test system were conducted and compared with conventional heat-shrinkable tubing.The sealing performance of the polymer heat-shrinkable tubing was investigated.The results indicated that deep rock ultrahigh-pressure condition and natural damage to the rock surface are the main causes of conventional heat-shrinkable tubing failure.In contrast,the damage rate of the proposed polymer heat-shrinkable tubing is extremely low,indicating that incorporating base material with high-performances can significantly enhance the pressure resistance of polymer heat-shrinkable tubing.Additionally,through the analysis of experimental results and the three-dimensional(3D)morphology of rock surfaces,the failure behavior of heat-shrinkable tubing under HTUP condition was revealed at the meso-structural level,and the proposed failure criteria,taking into account 3D morphology of rock surfaces and applicable to HTUP condition,have been advanced.The findings offer possibilities for triaxial rock mechanics testing in HTUP condition,providing theoretical and technical support for experiments and engineering applications in deep rock mechanics.展开更多
The plastic deformation introduced during the cooling stage(above 1000℃)of directional solidification is one of the primary reasons for the recrystallization of Ni-based single-crystal(SX)turbine blades in aeroengine...The plastic deformation introduced during the cooling stage(above 1000℃)of directional solidification is one of the primary reasons for the recrystallization of Ni-based single-crystal(SX)turbine blades in aeroengines during subsequent heat treatment.An as-cast SX superalloy DD33 was compressed at 1200°C with a Gleeble thermo-mechanical simulator to mimic such deformation.The microstructural evolution,dynamic recovery,and dynamic recrystallization nucleation of the as-cast SX superalloy during hot deformation are investigated.The results show that the highest stored energy occurs in the vicinity of the eutectics,and its energy in the interdendritic regions is higher than that in the dendrite cores/arms.The formation of deformation bands and related transition bands near the eutectics are the primary characteristics of microstructural evolution during hot deformation.The dynamic recovery in the eutectic regions includes the entanglement and annihilation of dislocations at eutectic/matrix interface,within nearby γ matrix or within the eutectic γ′phase,as well as the formation of dense dislocation networks in these sites.Subsequently,the low-angle grain boundaries in the transition bands migrate,merge,and finally transform into high-angle grain boundaries.In other words,the recrystallized grains nucleate near the eutectics via subgrain growth.In contrast,the dislocations only tangle and annihilate at the γ/γ′ interfaces in other interdendritic regions and the dendrite cores/arms without initiating recrystallization under moderate plastic deformation(ε_(plastic)=11.9%).This study will be helpful for understanding the local microstructural evolution of SX superalloys during directional solidification,as well as the recovery and recrystallization nucleation during the subsequent annealing.展开更多
To systematically validate and calibrate the theory and technology of the deep in-situ conditionpreserved coring, the in-situ conditions at different depths should be simulated, and the full-size coring tests should b...To systematically validate and calibrate the theory and technology of the deep in-situ conditionpreserved coring, the in-situ conditions at different depths should be simulated, and the full-size coring tests should be carried out in this simulated environment. Therefore, a deep-rock in-situ conditionpreserved coring calibration platform was designed and developed. The self-tightening sealing structure and the quick-disassembly structure were designed on the basis of an innovative segmented nonuniformdiameter structure, which was a breakthrough from the traditional high-pressure vessel frame and was verified by finite element simulation and actual testing under extreme working conditions, respectively.To simulate the actual deep in-situ environment with a temperature of 150℃ and pressure of 140 MPa for a large Φ450 mm×H1400 mm core, temperature and pressure control systems were designed by coupling, and a pre-embedded high-pressure-resistant temperature sensor was designed. Finally, highprecision assembly automation, complex movement coordination of the coring device with the platform,and rotary dynamic sealing were achieved by utilizing the combination of adaptive cabin body servo control and an adaptive mechanical structure in a limited space, laying a solid foundation for the calibration of in-situ condition-preserved coring.展开更多
Protonic ceramic fuel cells(PCFCs)have been recognized as promising power generation devices for future clean energy systems,owing to their relatively low activation energy for proton migration and high energy convers...Protonic ceramic fuel cells(PCFCs)have been recognized as promising power generation devices for future clean energy systems,owing to their relatively low activation energy for proton migration and high energy conversion efficiency.In certain application scenarios,the use of N_(2)O(a potent greenhouse gas),as an alternative oxidant to air,presents a feasible strategy.Herein,we report for the first time the operation of PCFCs employing N_(2)O as the oxidant.A hybrid Pr_(2)Ni_(0.6)Co_(0.4)O_(4-δ)(PNCO-214)catalyst is developed,comprising Ruddlesden-Popper(R-P)structured Pr_(4)Ni_(1.8)Co_(1.2)O_(10-δ)(PNCO-4310)and fluorite structured Pr_(6)O_(11)(PO-611),which synergistically exhibits exceptional catalytic activity toward both N_(2)O decomposition and the oxygen reduction reaction,achieving a conversion over 92% and an area specific resistance of 1.301Ω·cm^(2) at 600℃.Quasi-insitu temperature-dependent Fourier transform infrared(FTIR)and electrochemical impedance spectroscopy analyses reveal that abundant oxygen vacancies in PNCO-214 facilitate rapid adsorption and dissociation of N_(2)O into N_(2) and O_(2),while also promoting the surface exchange kinetics of proton/oxygen during oxygen reduction reaction(ORR).When applied in an anode-supported single cell with PNCO-214 cathode operating under N_(2)O,outstanding power density and low resistance are achieved,delivering 0.801 W·cm^(-2) and 0.245Ω·cm^(2) at 600℃.Satisfactory performance is also maintained even when the temperature is reduced to 500℃.Furthermore,the single cell demonstrates relatively good stability with negligible degradation over 130 h at 600℃ and 0.7 V.These findings underscore the potential of PNCO-214 as a highly effective cathode catalyst for enabling the use of N_(2)O as a viable oxidant in PCFCs for specific industrial applications.展开更多
Background:The Venus-P valve was the first self-expanding valve used world-wide for transcatheter pulmonary valve replacement(TPVR)in patients with severe pulmonary regurgitation(PR).We intended to report the extended...Background:The Venus-P valve was the first self-expanding valve used world-wide for transcatheter pulmonary valve replacement(TPVR)in patients with severe pulmonary regurgitation(PR).We intended to report the extended follow-up results from the prospective trial(No.NCT02590679).Methods:A total of 38 patients with severe PR(mean age 24.2±13.2)were included.Follow-up data were obtained after implanted at 1,6,and 12 months and yearly after.The frame geometry was assessed on post-implant computer tomography(CT)scanning by calculating the non-circularity[circularity ratio(minimum diameter/maximum diameter)<0.9]and under-expansion[expansion ratio(derived external valve area/nominal external valve area)<0.9).Adverse events(all-cause mortality,reintervention,valve dysfunction,stent fracture and endocarditis)were recorded.Results:All valves were implanted successfully with normal function at discharge.Geometric CT analysis showed underexpanded valve was detected in 22 patients(63%)and non-circular valve was seen in 16 patients(46%).During a median follow-up of 4.8 years(range 0.3-8.1),there were 1 death and 1 surgical explant,both resulting from endocarditis.Five-year freedom from valve dysfunction and stent fracture were 84.8%(95%CI 74.8-94.7)and 83.5%(95%CI 73.8-93.2).Endocarditis occurred in 3 patients at a median time of 7 months.Stent fracture was more common in patients with non-circularity stents.Conclusion:TPVR using Venus-P valve is associated with favorable outcomes at 5 years.Non-circular shapes in the valve level may have a higher risk of stent fracture.展开更多
The reversible solid oxide cell(RSOC)is an attractive technology to mutually convert power and chemicals at elevated temperatures.However,its development has been hindered mainly due to the absence of a highly active ...The reversible solid oxide cell(RSOC)is an attractive technology to mutually convert power and chemicals at elevated temperatures.However,its development has been hindered mainly due to the absence of a highly active and durable fuel electrode.Here,we report a phase-transformed CoFe-Sr_(3)Fe_(1.25)Mo_(0.75)O_(7)-δ(CoFe-SFM)fuel electrode consisting of CoFe nanoparticles and Ruddlesden-Popper-layered Sr_(3)Fe_(1.25)Mo_(0.75)O_(7)-δ(SFM)from a Sr_(2)Fe_(7/6)Mo_(0.5)Co_(1/3)O_(6)-δ(SFMCo)perovskite oxide after annealing in hydrogen and apply it to reversible CO/CO_(2)conversion in RSOC.The CoFeSFM fuel electrode shows improved catalytic activity by accelerating oxygen diffusion and surface kinetics towards the CO/CO_(2)conversion as demonstrated by the distribution of relaxation time(DRT)study and equivalent circuit model fitting analysis.Furthermore,an electrolyte-supported single cell is evaluated in the 2:1 CO-CO_(2)atmosphere at 800℃,which shows a peak power density of 259 mW cm^(-2)for CO oxidation and a current density of-0.453 A cm^(-2)at 1.3 V for CO_(2)reduction,which correspond to 3.079 and3.155 m L min-1cm^(-2)for the CO and CO_(2)conversion rates,respectively.More importantly,the reversible conversion is successfully demonstrated over 20 cyclic electrolysis and fuel cell switching test modes at 1.3 and 0.6 V.This work provides a useful guideline for designing a fuel electrode through a surface/interface exsolution process for RSOC towards efficient CO-CO_(2)reversible conversion.展开更多
Layered polymer suffers from a transfer barrier of photogenerated carriers resulting from the lack of interlamellar connection channels and intralayer disorder.Herein,a layer-stacked crystalline carbon nitride nanorod...Layered polymer suffers from a transfer barrier of photogenerated carriers resulting from the lack of interlamellar connection channels and intralayer disorder.Herein,a layer-stacked crystalline carbon nitride nanorod resembling an accordion(A-CNR)grafted abundant interlamellar oxygen-containing groups is ingeniously designed to break through the transfer barrier between layers without inserting any extra impurities.Density functional theory reveals that electrons are enriched near the oxygencontaining groups,promoting the extension and coupling of interlayer electron clouds.This reduces the interlamellar electrostatic potential barrier from 5.38 to 2.74 e V.Remarkably,the groups not only establish interlayer bridges but also guide carriers to the bridge entrance,further enhancing interlayer carrier transfer.Additionally,the intralayer carrier separation and transfer are also improved,profiting from the asymmetrical charge distribution and high crystallinity.A-CNR exhibits impressive photoelectric properties and photocatalytic water disinfection capability.Within 18 min irradiation,over 10~6 colony-forming units(CFU)/mL of bacteria are completely inactivated.Moreover,A-CNR can be dispersed in water over a long period benefiting from the introduced oxygen-containing groups,making it suitable for photocatalysis in the aqueous phase.The work provides a feasible and effective strategy to overcome the inherent barrier of layered polymeric photocatalysts.展开更多
It is challenging to theoretically predict the coefficient of thermal expansion(CTE)for binary AmBn crystals owing to the complexity of their crystal structures and computational procedures.Herein,the Pearson feature ...It is challenging to theoretically predict the coefficient of thermal expansion(CTE)for binary AmBn crystals owing to the complexity of their crystal structures and computational procedures.Herein,the Pearson feature selection method is utilized to identify nine key features associated closely with crystal structures,and a backpropagation neural network model with two hidden layers containing 24 and 15 neurons is adopted to achieve the optimal matching effect of the CTE,which is specifically optimized by the pelican optimization algorithm.Moreover,the black-box nature of the model is well elucidated by interpretability techniques of Shapley additive explanations(SHAP)and accumulated local effects(ALE),including the specific impact rules of each feature and the interaction effects between features on the CTE.It is found that the feature of average bond length contributes up to 27%,while low-influence features serve an important function in increasing prediction accuracy.The findings demonstrate the high efficiency and accuracy of the developed model for predicting the CTE of binary crystals.展开更多
The Internet of Things(IoT)1,2 employs a large number of spatially distributed wireless sensors to monitor physical environments,e.g.,temperature,humidity,and air pressure,and has many applications,including environme...The Internet of Things(IoT)1,2 employs a large number of spatially distributed wireless sensors to monitor physical environments,e.g.,temperature,humidity,and air pressure,and has many applications,including environmental monitoring3,health care monitoring4,smart cities5,and precision agriculture.A wireless sensor can collect,analyze,and transmit measurements of its environment1,2.Currently,wireless sensors used in the IoT are predominately based on electronic devices that may suffer from electromagnetic interference in many circumstances.Being immune to the electromagnetic interference,optical sensors provide a significant advantage in harsh environments6.Furthermore,by introducing optical resonance to enhance light–matter interactions,optical sensors based on resonators exhibit small footprints,extreme sensitivity,and versatile functionalities7,8,which can significantly enhance the capability and flexibility of wireless sensors.Here we provide the first demonstration of a wireless photonic sensor node based on a whisperinggallery-mode(WGM)optical resonator,in which light propagates along the circular rim of such a structure like a sphere,a disk,or a toroid by continuous total internal reflection.The sensor node is controlled via a customized iOS app.Its performance was studied in two practical scenarios:(1)real-time measurement of the air temperature over 12 h and(2)aerial mapping of the temperature distribution using a sensor node mounted on an unmanned drone.Our work demonstrates the capability of WGM optical sensors in practical applications and may pave the way for the large-scale deployment of WGM sensors in the IoT.展开更多
Optical whispering-gallery-mode microsensors are a promising platform for many applications,such as biomedical monitoring,magnetic sensing,and vibration detection.However,like many other micro/nanosensors,they cannot ...Optical whispering-gallery-mode microsensors are a promising platform for many applications,such as biomedical monitoring,magnetic sensing,and vibration detection.However,like many other micro/nanosensors,they cannot simultaneously have two critical properties–ultrahigh sensitivity and large detection area,which are desired for most sensing applications.Here,we report a novel scanning whispering-gallery-mode microprobe optimized for both features and demonstrate enhanced Raman spectroscopy,providing high-specificity information on molecular fingerprints that are important for numerous sensing applications.Combining the superiorities of whispering-gallery modes and nanoplasmonics,the microprobe exhibits a two-orders-of-magnitude sensitivity improvement over traditional plasmonics-only enhancement;this leads to molecular detection demonstrated with stronger target signals but less optical power required than surface-enhanced-Raman-spectroscopy substrates.Furthermore,the scanning microprobe greatly expands the effective detection area and realizes two-dimensional micron-resolution Raman imaging of molecular distribution.The versatile and ultrasensitive scanning microprobe configuration will thus benefit material characterization,chemical imaging,and quantum-enhanced sensing.展开更多
Stable and flexible metal nanoparticles(NPs)with regeneration ability are critical for long-term operation of solid oxide electrolysis cells(SOECs).Herein,a novel perovskite electrode with stoichiometric Pr_(0.4)Sr_(0...Stable and flexible metal nanoparticles(NPs)with regeneration ability are critical for long-term operation of solid oxide electrolysis cells(SOECs).Herein,a novel perovskite electrode with stoichiometric Pr_(0.4)Sr_(0.6)Co_(0.125)Fe_(0.75)Mo_(0.125)O_(3)−δ(PSFCM)is synthesized and studied,which undergoes multiple redox cycles to validate its structural stability and NPs reversibility.The Co-Fe alloy has exsolved from the parent bulk under reducing atmosphere,and is capable of reincorporation into the parent oxide after re-oxidation treatment.During the redox process,we successfully manipulate the size and population density of the exsolved NPs,and find that the average particle size significantly reduces but the population density increases correspondingly.The electrode polarization resistance of the symmetric cell remains stable for 450 h,and even activates after the redox cycling,which may be attributed to the higher quantity and larger specific surface area of the regenerated Co-Fe alloy NPs.Moreover,the electrochemical performance towards carbon dioxide reduction reaction(CO_(2)RR)is evaluated,and the CO_(2)electrolyzer consisting of CoFe@PSCFM-Ce_(0.8)Sm_(0.2)O_(1.9)(SDC)dual-phase electrode exhibits an excellent current density of 1.42 A·cm^(−2)at 1.6 V,which reaches 1.7 times higher than 0.83 A·cm^(−2)for the pristine PSCFM electrode.Overall,with this flexible and reversible high-performance SOEC cathode material,new options and perspectives are provided for the efficient and durable CO_(2)electrolysis.展开更多
In data-driven materials design where the target materials have limited data,the transfer machine learning from large known source materials,becomes a demanding strategy especially across different crystal structures....In data-driven materials design where the target materials have limited data,the transfer machine learning from large known source materials,becomes a demanding strategy especially across different crystal structures.In this work,we proposed a deep transfer learning approach to predict thermodynamically stable perovskite oxides based on a large computational dataset of spinel oxides.The deep neural network(DNN)source domain model with“Center-Environment”(CE)features was first developed using the formation energy of 5329 spinel oxide structures and then was fine-tuned by learning a small dataset of 855 perovskite oxide structures,leading to a transfer learning model with good transferability in the target domain of perovskite oxides.Based on the transferred model,we further predicted the formation energy of potential 5329 perovskite structures with combination of 73 elements.Combining the criteria of formation energy and structure factors including tolerance factor(0.7<t≤1.1)and octahedron factor(0.45<μ<0.7),we predicted 1314 thermodynamically stable perovskite oxides,among which 144 oxides were reported to be synthesized experimentally,10 oxides were predicted computationally by other literatures,301 oxides were recorded in the Materials Project database,and 859 oxides have been first reported.Combing with the structure-informed features the transfer machine learning approach in this work takes the advantage of existing data to predict new structures at a lower cost,providing an effective acceleration strategy for the expensive high-throughput computational screening in materials design.The predicted stable novel perovskite oxides serve as a rich platform for exploring potential renewable energy and electronic materials applications.展开更多
Summary of main observation and conclusion Schisandraceae triterpenoids are novel natural products that contain highly fused ring systems bearing multiple chiral centers surrounding. Some of them exhibit promising bio...Summary of main observation and conclusion Schisandraceae triterpenoids are novel natural products that contain highly fused ring systems bearing multiple chiral centers surrounding. Some of them exhibit promising bioactivities, such as antitumor, anti‐HIV, etc. In this article, we describe our efforts to the collective total synthesis of schilancidilactones A, B, schilancitrilactones A, B, C, and 20‐epi‐schilancitrilactone A from common precursors. An intramolecular radical cyclization, late‐stage halogenation and AIBN‐mediated or Ni‐catalyzed intermolecular radical cross coupling reaction were employed as the key steps.展开更多
Recently,the emerging 2μm waveband has gained increasing interest due to its great potential for a wide scope of applications.Compared with the existing optical communication windows at shorter wavelengths,it also of...Recently,the emerging 2μm waveband has gained increasing interest due to its great potential for a wide scope of applications.Compared with the existing optical communication windows at shorter wavelengths,it also offers distinct advantages of lower nonlinear absorption,better fabrication tolerance,and larger free carrier plasma effects for silicon photonics,which has been a proven device technology.While much progress has been witnessed for silicon photonics at the 2μm waveband,the primary challenge still exists for on-chip detectors.Despite the maturity and compatibility of the waveguide coupled photodetectors made of germanium,the 2μm regime is far beyond its cutoff wavelength.In this work,we demonstrate an efficient and high-speed on-chip waveguidecoupled germanium photodetector operating at the 2μm waveband.The weak sub-bandgap absorption of epitaxial germanium is greatly enhanced by a lateral separation absorption charge multiplication structure.The detector is fabricated by the standard process offered by a commercial foundry.The device has a benchmark performance with responsivity of 1.05 A/W and 3 dB bandwidth of 7.12 GHz,which is able to receive high-speed signals with up to 20 Gbit/s data rate.The availability of such an efficient and fast on-chip detector circumvents the barriers between silicon photonic integrated circuits and the potential applications at the 2μm waveband.展开更多
基金funding provided by the National Natural Science Foundation of China(Grant Nos.51827901 and 52174084)the Natural Science Foundation of Sichuan Provence,China(Grant No.2022NSFSC0005).
文摘The deep underground engineering will face high-temperature and ultrahigh-pressure(HTUP)condition.Indoor triaxial testing is an important means to investigate this challenge in rock mechanics and rock engineering.Heat-shrinkable tubing,as a seal on the rock surface,is crucial for reconstructing deep rock in situ conditions(ensuring the accuracy and effectiveness of confining pressure and pore pressure).However,there are few reports on testing such material under HTUP condition.Thus,the mechanical and sealing performances of existing heat-shrinkable tubing under HTUP condition is still immature.The motivation of this study is to advance deep rock mechanics and engineering by developing a polymer heat-shrinkable tubing(pressure larger than 140 MPa and temperature greater than 150℃).Experiments using the deep rock in situ thermal insulation coring test system were conducted and compared with conventional heat-shrinkable tubing.The sealing performance of the polymer heat-shrinkable tubing was investigated.The results indicated that deep rock ultrahigh-pressure condition and natural damage to the rock surface are the main causes of conventional heat-shrinkable tubing failure.In contrast,the damage rate of the proposed polymer heat-shrinkable tubing is extremely low,indicating that incorporating base material with high-performances can significantly enhance the pressure resistance of polymer heat-shrinkable tubing.Additionally,through the analysis of experimental results and the three-dimensional(3D)morphology of rock surfaces,the failure behavior of heat-shrinkable tubing under HTUP condition was revealed at the meso-structural level,and the proposed failure criteria,taking into account 3D morphology of rock surfaces and applicable to HTUP condition,have been advanced.The findings offer possibilities for triaxial rock mechanics testing in HTUP condition,providing theoretical and technical support for experiments and engineering applications in deep rock mechanics.
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFB3707104,and 2022YFB3708100)the National Science and Technology Major Project(No.J2019-Ⅵ-0010-0124)+1 种基金the National Natural Science Foundation of China(Nos.52331005,91860201,52271042,and 52171095)the Science Center for Gas Turbine Project(No.P2022-C-Ⅳ-001-001).
文摘The plastic deformation introduced during the cooling stage(above 1000℃)of directional solidification is one of the primary reasons for the recrystallization of Ni-based single-crystal(SX)turbine blades in aeroengines during subsequent heat treatment.An as-cast SX superalloy DD33 was compressed at 1200°C with a Gleeble thermo-mechanical simulator to mimic such deformation.The microstructural evolution,dynamic recovery,and dynamic recrystallization nucleation of the as-cast SX superalloy during hot deformation are investigated.The results show that the highest stored energy occurs in the vicinity of the eutectics,and its energy in the interdendritic regions is higher than that in the dendrite cores/arms.The formation of deformation bands and related transition bands near the eutectics are the primary characteristics of microstructural evolution during hot deformation.The dynamic recovery in the eutectic regions includes the entanglement and annihilation of dislocations at eutectic/matrix interface,within nearby γ matrix or within the eutectic γ′phase,as well as the formation of dense dislocation networks in these sites.Subsequently,the low-angle grain boundaries in the transition bands migrate,merge,and finally transform into high-angle grain boundaries.In other words,the recrystallized grains nucleate near the eutectics via subgrain growth.In contrast,the dislocations only tangle and annihilate at the γ/γ′ interfaces in other interdendritic regions and the dendrite cores/arms without initiating recrystallization under moderate plastic deformation(ε_(plastic)=11.9%).This study will be helpful for understanding the local microstructural evolution of SX superalloys during directional solidification,as well as the recovery and recrystallization nucleation during the subsequent annealing.
基金supported by National Natural Science Foundation of China(Nos.51827901 and 52225403)the Shenzhen National Science Fund for Distinguished Young Scholars(RCJC20210706091948015).
文摘To systematically validate and calibrate the theory and technology of the deep in-situ conditionpreserved coring, the in-situ conditions at different depths should be simulated, and the full-size coring tests should be carried out in this simulated environment. Therefore, a deep-rock in-situ conditionpreserved coring calibration platform was designed and developed. The self-tightening sealing structure and the quick-disassembly structure were designed on the basis of an innovative segmented nonuniformdiameter structure, which was a breakthrough from the traditional high-pressure vessel frame and was verified by finite element simulation and actual testing under extreme working conditions, respectively.To simulate the actual deep in-situ environment with a temperature of 150℃ and pressure of 140 MPa for a large Φ450 mm×H1400 mm core, temperature and pressure control systems were designed by coupling, and a pre-embedded high-pressure-resistant temperature sensor was designed. Finally, highprecision assembly automation, complex movement coordination of the coring device with the platform,and rotary dynamic sealing were achieved by utilizing the combination of adaptive cabin body servo control and an adaptive mechanical structure in a limited space, laying a solid foundation for the calibration of in-situ condition-preserved coring.
基金financially supported by the National Key R&D Program of China(No.2024YFF0506300)National Natural Science Foundation of China(No.52336009)+5 种基金Key Research and Development Program of Shaanxi(No.2024CY2-GJHX-66)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010429)Natural Science Basic Research Plan in Shaanxi Province of China(No.2024JC-YBQN-0475)Xidian University Specially Funded Project for Interdisciplinary Exploration(No.TZJH2024063)the Fundamental Research Funds for the Central Universities(No.QTZX23061)the Innovation Center of Nuclear Power Technology(No.HDLCXZX-2022-ZH-013).
文摘Protonic ceramic fuel cells(PCFCs)have been recognized as promising power generation devices for future clean energy systems,owing to their relatively low activation energy for proton migration and high energy conversion efficiency.In certain application scenarios,the use of N_(2)O(a potent greenhouse gas),as an alternative oxidant to air,presents a feasible strategy.Herein,we report for the first time the operation of PCFCs employing N_(2)O as the oxidant.A hybrid Pr_(2)Ni_(0.6)Co_(0.4)O_(4-δ)(PNCO-214)catalyst is developed,comprising Ruddlesden-Popper(R-P)structured Pr_(4)Ni_(1.8)Co_(1.2)O_(10-δ)(PNCO-4310)and fluorite structured Pr_(6)O_(11)(PO-611),which synergistically exhibits exceptional catalytic activity toward both N_(2)O decomposition and the oxygen reduction reaction,achieving a conversion over 92% and an area specific resistance of 1.301Ω·cm^(2) at 600℃.Quasi-insitu temperature-dependent Fourier transform infrared(FTIR)and electrochemical impedance spectroscopy analyses reveal that abundant oxygen vacancies in PNCO-214 facilitate rapid adsorption and dissociation of N_(2)O into N_(2) and O_(2),while also promoting the surface exchange kinetics of proton/oxygen during oxygen reduction reaction(ORR).When applied in an anode-supported single cell with PNCO-214 cathode operating under N_(2)O,outstanding power density and low resistance are achieved,delivering 0.801 W·cm^(-2) and 0.245Ω·cm^(2) at 600℃.Satisfactory performance is also maintained even when the temperature is reduced to 500℃.Furthermore,the single cell demonstrates relatively good stability with negligible degradation over 130 h at 600℃ and 0.7 V.These findings underscore the potential of PNCO-214 as a highly effective cathode catalyst for enabling the use of N_(2)O as a viable oxidant in PCFCs for specific industrial applications.
文摘Background:The Venus-P valve was the first self-expanding valve used world-wide for transcatheter pulmonary valve replacement(TPVR)in patients with severe pulmonary regurgitation(PR).We intended to report the extended follow-up results from the prospective trial(No.NCT02590679).Methods:A total of 38 patients with severe PR(mean age 24.2±13.2)were included.Follow-up data were obtained after implanted at 1,6,and 12 months and yearly after.The frame geometry was assessed on post-implant computer tomography(CT)scanning by calculating the non-circularity[circularity ratio(minimum diameter/maximum diameter)<0.9]and under-expansion[expansion ratio(derived external valve area/nominal external valve area)<0.9).Adverse events(all-cause mortality,reintervention,valve dysfunction,stent fracture and endocarditis)were recorded.Results:All valves were implanted successfully with normal function at discharge.Geometric CT analysis showed underexpanded valve was detected in 22 patients(63%)and non-circular valve was seen in 16 patients(46%).During a median follow-up of 4.8 years(range 0.3-8.1),there were 1 death and 1 surgical explant,both resulting from endocarditis.Five-year freedom from valve dysfunction and stent fracture were 84.8%(95%CI 74.8-94.7)and 83.5%(95%CI 73.8-93.2).Endocarditis occurred in 3 patients at a median time of 7 months.Stent fracture was more common in patients with non-circularity stents.Conclusion:TPVR using Venus-P valve is associated with favorable outcomes at 5 years.Non-circular shapes in the valve level may have a higher risk of stent fracture.
基金financially supported by the National Natural Science Foundation (52002249,51402093 and 21706162)Guangdong Basic and Applied Basic Research Foundation (2019A1515110025 and 2017A 030313289)+3 种基金the Research Grant for Scientific Platform and Project of Guangdong Provincial Education Office (2019KTSCX151)China Postdoctoral Science Foundation (2020M682872)Shenzhen Government’s Plan of Science and Technology (JCYJ201803005125247308)Technical support from the Instrumental Analysis Center of Shenzhen University (Xili Campus) is also appreciated。
文摘The reversible solid oxide cell(RSOC)is an attractive technology to mutually convert power and chemicals at elevated temperatures.However,its development has been hindered mainly due to the absence of a highly active and durable fuel electrode.Here,we report a phase-transformed CoFe-Sr_(3)Fe_(1.25)Mo_(0.75)O_(7)-δ(CoFe-SFM)fuel electrode consisting of CoFe nanoparticles and Ruddlesden-Popper-layered Sr_(3)Fe_(1.25)Mo_(0.75)O_(7)-δ(SFM)from a Sr_(2)Fe_(7/6)Mo_(0.5)Co_(1/3)O_(6)-δ(SFMCo)perovskite oxide after annealing in hydrogen and apply it to reversible CO/CO_(2)conversion in RSOC.The CoFeSFM fuel electrode shows improved catalytic activity by accelerating oxygen diffusion and surface kinetics towards the CO/CO_(2)conversion as demonstrated by the distribution of relaxation time(DRT)study and equivalent circuit model fitting analysis.Furthermore,an electrolyte-supported single cell is evaluated in the 2:1 CO-CO_(2)atmosphere at 800℃,which shows a peak power density of 259 mW cm^(-2)for CO oxidation and a current density of-0.453 A cm^(-2)at 1.3 V for CO_(2)reduction,which correspond to 3.079 and3.155 m L min-1cm^(-2)for the CO and CO_(2)conversion rates,respectively.More importantly,the reversible conversion is successfully demonstrated over 20 cyclic electrolysis and fuel cell switching test modes at 1.3 and 0.6 V.This work provides a useful guideline for designing a fuel electrode through a surface/interface exsolution process for RSOC towards efficient CO-CO_(2)reversible conversion.
基金supported by the National Natural Science Foundation of China(52103315)the Natural Science Foundation of Jiangsu(BK20221270)+3 种基金the Science and Technology Program of Suzhou(SS202113)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_0703)the Open Project of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province(CSPC202310)the Industrial Guided Development Project of Suzhou Yangcheng Lake。
文摘Layered polymer suffers from a transfer barrier of photogenerated carriers resulting from the lack of interlamellar connection channels and intralayer disorder.Herein,a layer-stacked crystalline carbon nitride nanorod resembling an accordion(A-CNR)grafted abundant interlamellar oxygen-containing groups is ingeniously designed to break through the transfer barrier between layers without inserting any extra impurities.Density functional theory reveals that electrons are enriched near the oxygencontaining groups,promoting the extension and coupling of interlayer electron clouds.This reduces the interlamellar electrostatic potential barrier from 5.38 to 2.74 e V.Remarkably,the groups not only establish interlayer bridges but also guide carriers to the bridge entrance,further enhancing interlayer carrier transfer.Additionally,the intralayer carrier separation and transfer are also improved,profiting from the asymmetrical charge distribution and high crystallinity.A-CNR exhibits impressive photoelectric properties and photocatalytic water disinfection capability.Within 18 min irradiation,over 10~6 colony-forming units(CFU)/mL of bacteria are completely inactivated.Moreover,A-CNR can be dispersed in water over a long period benefiting from the introduced oxygen-containing groups,making it suitable for photocatalysis in the aqueous phase.The work provides a feasible and effective strategy to overcome the inherent barrier of layered polymeric photocatalysts.
基金supported by the Key R&D Program of Shaanxi(No.2025CY-YBXM-145)the National Natural Science Foundation of China(No.62371366)+3 种基金the Central Guiding Local Science and Technology Development Funds of Guizhou(No.2024-034)the Open Project of Yunnan Precious Metals Laboratory Co.,Ltd.(No.YPML-2023050246)the Innovation Capability Support Program of Shaanxi(Nos.2023-CX-PT-30 and 2022TD-28)the Fundamental Research Funds for the Central Universities(No.ZYTS25232).
文摘It is challenging to theoretically predict the coefficient of thermal expansion(CTE)for binary AmBn crystals owing to the complexity of their crystal structures and computational procedures.Herein,the Pearson feature selection method is utilized to identify nine key features associated closely with crystal structures,and a backpropagation neural network model with two hidden layers containing 24 and 15 neurons is adopted to achieve the optimal matching effect of the CTE,which is specifically optimized by the pelican optimization algorithm.Moreover,the black-box nature of the model is well elucidated by interpretability techniques of Shapley additive explanations(SHAP)and accumulated local effects(ALE),including the specific impact rules of each feature and the interaction effects between features on the CTE.It is found that the feature of average bond length contributes up to 27%,while low-influence features serve an important function in increasing prediction accuracy.The findings demonstrate the high efficiency and accuracy of the developed model for predicting the CTE of binary crystals.
文摘The Internet of Things(IoT)1,2 employs a large number of spatially distributed wireless sensors to monitor physical environments,e.g.,temperature,humidity,and air pressure,and has many applications,including environmental monitoring3,health care monitoring4,smart cities5,and precision agriculture.A wireless sensor can collect,analyze,and transmit measurements of its environment1,2.Currently,wireless sensors used in the IoT are predominately based on electronic devices that may suffer from electromagnetic interference in many circumstances.Being immune to the electromagnetic interference,optical sensors provide a significant advantage in harsh environments6.Furthermore,by introducing optical resonance to enhance light–matter interactions,optical sensors based on resonators exhibit small footprints,extreme sensitivity,and versatile functionalities7,8,which can significantly enhance the capability and flexibility of wireless sensors.Here we provide the first demonstration of a wireless photonic sensor node based on a whisperinggallery-mode(WGM)optical resonator,in which light propagates along the circular rim of such a structure like a sphere,a disk,or a toroid by continuous total internal reflection.The sensor node is controlled via a customized iOS app.Its performance was studied in two practical scenarios:(1)real-time measurement of the air temperature over 12 h and(2)aerial mapping of the temperature distribution using a sensor node mounted on an unmanned drone.Our work demonstrates the capability of WGM optical sensors in practical applications and may pave the way for the large-scale deployment of WGM sensors in the IoT.
基金This work was supported by National Institutes of Health under Grant No.NIH-1R21EB03084501A1.The authors acknowledge the Institute of Materials Science and Engineering(IMSE)and Nano Research Facility(NRF)at Washington University in St.Louis for the use of instruments,financial support,and staff assistance.
文摘Optical whispering-gallery-mode microsensors are a promising platform for many applications,such as biomedical monitoring,magnetic sensing,and vibration detection.However,like many other micro/nanosensors,they cannot simultaneously have two critical properties–ultrahigh sensitivity and large detection area,which are desired for most sensing applications.Here,we report a novel scanning whispering-gallery-mode microprobe optimized for both features and demonstrate enhanced Raman spectroscopy,providing high-specificity information on molecular fingerprints that are important for numerous sensing applications.Combining the superiorities of whispering-gallery modes and nanoplasmonics,the microprobe exhibits a two-orders-of-magnitude sensitivity improvement over traditional plasmonics-only enhancement;this leads to molecular detection demonstrated with stronger target signals but less optical power required than surface-enhanced-Raman-spectroscopy substrates.Furthermore,the scanning microprobe greatly expands the effective detection area and realizes two-dimensional micron-resolution Raman imaging of molecular distribution.The versatile and ultrasensitive scanning microprobe configuration will thus benefit material characterization,chemical imaging,and quantum-enhanced sensing.
基金supported by the National Natural Science Foundation of China(No.U21A20317)the National Key Research and Development Program of China(No.2022YFA1504701)+2 种基金the Fundamental Research Funds for the Central Universities(No.2042022gf0002)the start-up research funds from Wuhan Institute of Technology(No.K202201)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010429).
文摘Stable and flexible metal nanoparticles(NPs)with regeneration ability are critical for long-term operation of solid oxide electrolysis cells(SOECs).Herein,a novel perovskite electrode with stoichiometric Pr_(0.4)Sr_(0.6)Co_(0.125)Fe_(0.75)Mo_(0.125)O_(3)−δ(PSFCM)is synthesized and studied,which undergoes multiple redox cycles to validate its structural stability and NPs reversibility.The Co-Fe alloy has exsolved from the parent bulk under reducing atmosphere,and is capable of reincorporation into the parent oxide after re-oxidation treatment.During the redox process,we successfully manipulate the size and population density of the exsolved NPs,and find that the average particle size significantly reduces but the population density increases correspondingly.The electrode polarization resistance of the symmetric cell remains stable for 450 h,and even activates after the redox cycling,which may be attributed to the higher quantity and larger specific surface area of the regenerated Co-Fe alloy NPs.Moreover,the electrochemical performance towards carbon dioxide reduction reaction(CO_(2)RR)is evaluated,and the CO_(2)electrolyzer consisting of CoFe@PSCFM-Ce_(0.8)Sm_(0.2)O_(1.9)(SDC)dual-phase electrode exhibits an excellent current density of 1.42 A·cm^(−2)at 1.6 V,which reaches 1.7 times higher than 0.83 A·cm^(−2)for the pristine PSCFM electrode.Overall,with this flexible and reversible high-performance SOEC cathode material,new options and perspectives are provided for the efficient and durable CO_(2)electrolysis.
基金This work was supported by the National Natural Science Foundation of China[Nos.22177067]Sino-German Mobility Program[No.M-0209]+3 种基金the Shanghai Rising-Star Program[No.20QA1403400]the Key Basic Research Program of Science and Technology Commission of Shanghai Municipality(20JC1415300)This work was also supported the Key Research Project of Zhejiang Laboratory(No.2021PE0AC02)Shanghai Technical Service Center for Advanced Ceramics Structure Design and Precision Manufacturing(No.20DZ2294000).The authors acknowledge the Beijing Super Cloud Computing Center,Hefei Advanced Computing Center,and Shanghai University for providing HPC resources.
文摘In data-driven materials design where the target materials have limited data,the transfer machine learning from large known source materials,becomes a demanding strategy especially across different crystal structures.In this work,we proposed a deep transfer learning approach to predict thermodynamically stable perovskite oxides based on a large computational dataset of spinel oxides.The deep neural network(DNN)source domain model with“Center-Environment”(CE)features was first developed using the formation energy of 5329 spinel oxide structures and then was fine-tuned by learning a small dataset of 855 perovskite oxide structures,leading to a transfer learning model with good transferability in the target domain of perovskite oxides.Based on the transferred model,we further predicted the formation energy of potential 5329 perovskite structures with combination of 73 elements.Combining the criteria of formation energy and structure factors including tolerance factor(0.7<t≤1.1)and octahedron factor(0.45<μ<0.7),we predicted 1314 thermodynamically stable perovskite oxides,among which 144 oxides were reported to be synthesized experimentally,10 oxides were predicted computationally by other literatures,301 oxides were recorded in the Materials Project database,and 859 oxides have been first reported.Combing with the structure-informed features the transfer machine learning approach in this work takes the advantage of existing data to predict new structures at a lower cost,providing an effective acceleration strategy for the expensive high-throughput computational screening in materials design.The predicted stable novel perovskite oxides serve as a rich platform for exploring potential renewable energy and electronic materials applications.
文摘Summary of main observation and conclusion Schisandraceae triterpenoids are novel natural products that contain highly fused ring systems bearing multiple chiral centers surrounding. Some of them exhibit promising bioactivities, such as antitumor, anti‐HIV, etc. In this article, we describe our efforts to the collective total synthesis of schilancidilactones A, B, schilancitrilactones A, B, C, and 20‐epi‐schilancitrilactone A from common precursors. An intramolecular radical cyclization, late‐stage halogenation and AIBN‐mediated or Ni‐catalyzed intermolecular radical cross coupling reaction were employed as the key steps.
基金National Natural Science Foundation of China(U21A20454)Science,Technology and Innovation Commission of Shenzhen Municipality (JCYJ20220818102406013,RCYX20210609103707009)Natural Science Foundation of Guangdong Province for Distinguished Young Scholars(2022B1515020057)。
文摘Recently,the emerging 2μm waveband has gained increasing interest due to its great potential for a wide scope of applications.Compared with the existing optical communication windows at shorter wavelengths,it also offers distinct advantages of lower nonlinear absorption,better fabrication tolerance,and larger free carrier plasma effects for silicon photonics,which has been a proven device technology.While much progress has been witnessed for silicon photonics at the 2μm waveband,the primary challenge still exists for on-chip detectors.Despite the maturity and compatibility of the waveguide coupled photodetectors made of germanium,the 2μm regime is far beyond its cutoff wavelength.In this work,we demonstrate an efficient and high-speed on-chip waveguidecoupled germanium photodetector operating at the 2μm waveband.The weak sub-bandgap absorption of epitaxial germanium is greatly enhanced by a lateral separation absorption charge multiplication structure.The detector is fabricated by the standard process offered by a commercial foundry.The device has a benchmark performance with responsivity of 1.05 A/W and 3 dB bandwidth of 7.12 GHz,which is able to receive high-speed signals with up to 20 Gbit/s data rate.The availability of such an efficient and fast on-chip detector circumvents the barriers between silicon photonic integrated circuits and the potential applications at the 2μm waveband.
