Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of ...Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of hydrogen sulfide(SOH_(2)S) to elemental sulfur(S) has emerged as a sustainable and environmentally friendly solution.Due to its unique properties,iron oxide has been extensively investigated as a catalyst for SOH_(2)S;however,rapid deactivation has remained a significant drawback.The causes of iron oxide-based catalysts deactivation mechanisms in SOH_(2)S,including sulfur or sulfate deposition,the transformation of iron species,sintering and excessive oxygen vacancy formation,and active site loss,are thoroughly examined in this review.By focusing on the deactivation mechanisms,this review aims to provide valuable insights into enhancing the stability and efficiency of iron-based catalysts for SOH_(2)S.展开更多
Anode materials are an essential part of lithium-ion batteries(LIBs),which determine the performance and safety of LIBs.Currently,graphite,as the anode material of commercial LIBs,is limited by its low theoretical cap...Anode materials are an essential part of lithium-ion batteries(LIBs),which determine the performance and safety of LIBs.Currently,graphite,as the anode material of commercial LIBs,is limited by its low theoretical capacity of 372 mA·h·g^(−1),thus hindering further development toward high-capacity and large-scale applications.Alkaline earth metal iron-based oxides are considered a promising candidate to replace graphite because of their low preparation cost,good thermal stability,superior stability,and high electrochemical performance.Nonetheless,many issues and challenges remain to be addressed.Herein,we systematically summarize the research progress of alkaline earth metal iron-based oxides as LIB anodes.Meanwhile,the material and structural properties,synthesis methods,electrochemical reaction mechanisms,and improvement strategies are introduced.Finally,existing challenges and future research directions are discussed to accelerate their practical application in commercial LIBs.展开更多
Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,...Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,FeS,the least studied Fe X compound(due to the difficulty in synthesizing high quality macroscopic crystals)attracted much attention because of its puzzling superconducting pairing symmetry.In this work,combining scanning tunneling microscopy and angle resolved photoemission spectroscopy(ARPES)with sub-micron spatial resolution,we investigate the intrinsic electronic structures of superconducting FeS from individual single crystalline domains.Unlike FeTe or FeSe,FeS remains identical tetragonal structure from room temperature down to 5 K,and the band structures observed can be well reproduced by our ab-initio calculations.Remarkably,mixed with the 1×1 tetragonal metallic phase,we also observe the coexistence of √5×√5 reconstructed insulating phase in the crystal,which not only helps explain the unusual properties of FeS,but also demonstrates the importance of using spatially resolved experimental tools in the study of this compound.展开更多
Polynorbornenes were synthesized in the presence of an iron based catalyst, 2,6-bis[1-（2,6-diisopropyl-phenylimino）ethyl]pyridine iron（Ⅱ） dichloride. The FTIR, 1H NMR and 13C NMR analysis results revealed that th...Polynorbornenes were synthesized in the presence of an iron based catalyst, 2,6-bis[1-（2,6-diisopropyl-phenylimino）ethyl]pyridine iron（Ⅱ） dichloride. The FTIR, 1H NMR and 13C NMR analysis results revealed that the structure of the obtained polynorbornenes consisted of vinyl addition polymer substructures without any ring-opening structures. The polymers were amorphous with a short-range order, displayed in the WAXD（wide angle X-ray diffraction） diagrams. The glass transition temperatures ranged from 200 to 400 ℃. The effects of the polymerization reaction conditions, such as Al/Fe molar ratio and toluene/CH2Cl2 volume ratio, on the activity, intrinsic viscosity and Tg were also studied.展开更多
Majorana zero modes(MZMs) are Majorana-fermion-like quasiparticles existing in crystals or hybrid platforms with topologically non-trivial electronic structures. They obey non-Abelian braiding statistics and are consi...Majorana zero modes(MZMs) are Majorana-fermion-like quasiparticles existing in crystals or hybrid platforms with topologically non-trivial electronic structures. They obey non-Abelian braiding statistics and are considered promising to realize topological quantum computing. Discovery of MZM in the vortices of the iron-based superconductors(IBSs)has recently fueled the Majorana research in a way which not only removes the material barrier requiring construction of complicated hybrid artificial structures, but also enables observation of pure MZMs under higher temperatures. So far,MZMs have been observed in iron-based superconductors including FeTe_(0.55)Se_(0.45),(Li_(0.84)Fe_(0.16))OHFe Se, Ca KFe_(4)As_(4),and Li Fe As. In this topical review, we present an overview of the recent STM studies on the MZMs in IBSs. We start with the observation of MZMs in the vortices in FeTe_(0.55)Se_(0.45)and discuss the pros and cons of FeTe_(0.55)Se_(0.45) compared with other platforms. We then review the following up discovery of MZMs in vortices of Ca KFe_(4)As_(4), impurity-assisted vortices of Li Fe As, and quantum anomalous vortices in FeTe_(0.55)Se_(0.45), illustrating the pathway of the developments of MZM research in IBSs. Finally, we give perspective on future experimental works in this field.展开更多
1 INTRODUCTIONTemperature-Programmed Reduction(TPR)is widely used in the study of the reduc-tion properties of catalysts[1-4].It does not depend on any specific property exceptthe reducibility of the catalyst.Paramete...1 INTRODUCTIONTemperature-Programmed Reduction(TPR)is widely used in the study of the reduc-tion properties of catalysts[1-4].It does not depend on any specific property exceptthe reducibility of the catalyst.Parameters of the TPR profile,such as peaktemperature,peak area and peak width,are capable of providing certain indications onthe original state of the reduced species,the interaction effects between active compo-nents and promoter or supporter,and other reduction properties of the catalyst.展开更多
In order to adapt to the high temperature and heavy load process environment of large forgings,a novel die with"fist-like"structure is designed.The“fist-like”die mainly consists of“skin”layer,“bone”lay...In order to adapt to the high temperature and heavy load process environment of large forgings,a novel die with"fist-like"structure is designed.The“fist-like”die mainly consists of“skin”layer,“bone”layer and matrix.To obtain the material with good supportability and good bonding strength with the“skin”layer,iron-based alloys RMD248 and CN72 were selected to make the"bone"layer,and the properties were compared.In this paper,the"bone"layer and the"skin"layer(CHN327)were surfaced on 5CrNiMo matrix by wire arc additive manufacture(WAAM).Then,cyclic heating to 500℃and thermal compression with a maximum deformation of 30%were adapted to test the high temperature mechanical properties.The microstructure changes before and after thermal cycles and compressions were observed by optical microscopy(OM),X-ray diffraction(XRD),energy dispersive spectrometer(EDS)and scanning electron microscopy(SEM).The results show that CN72 has more carbides than RMD248 at the joint surface,which makes it easy to form brittle fracture at the joint.Mechanical properties were tested by using microhardness machine.Meanwhile,hot tensile tests were performed to study bonding strength between the“skin”layer and the“bone”layer.The results show that the RMD248 has stable microhardness distribution while the microhardness of CN72 decreases with the distance from the interface.And the ultimate tensile strength between CN72 and CHN327 is higher than RMD248 in the temperature range of 400-450℃.It can be inferred that CN72 has higher inter-layer wear resistance and RMD248 has more stable high temperature performance.展开更多
Iron-plating technology used for restoration of axis parts was applied to the manufacture of diamond bits in this paper.The technology for electroplating diamond bit of iron matrix was mastered through repeated experi...Iron-plating technology used for restoration of axis parts was applied to the manufacture of diamond bits in this paper.The technology for electroplating diamond bit of iron matrix was mastered through repeated experiments and research.The productive practice indicated that the DC-electroplated iron matrix of diamond bit has high hardness and good diamond exposure ability;the drilling rate of electroplated iron-based diamond bit was 2 m/h when drilling in grade 9 granite and bit life can reach 44 m,which can satisfy the drilling production requirements.展开更多
Modulated electronic state due to the layered crystal structures brings about moderate anisotropy of superconductivity in the iron-based superconductors and thus Abrikosov vortices are expected in the mixed state.Howe...Modulated electronic state due to the layered crystal structures brings about moderate anisotropy of superconductivity in the iron-based superconductors and thus Abrikosov vortices are expected in the mixed state.However,based on the angular and temperature dependent transport measurements in iron-based superconductor Ca_(10)(Pt_(3)As_(8))((Fe_(0.9)Pt_(0.1))_(2)As_(2))_(5) with Tc(≌)12 K,we find clear evidences of a crossover from Abrikosov vortices to Josephson vortices at a crossover temperature T*(≌)7 K,when the applied magnetic field is parallel to the superconducting FeAs layers,i.e.,the angle between the magnetic field and the FeAs layers θ=0°.This crossover to Josephson vortices is demonstrated by an abnormal decrease(increase)of the critical current(flux-flow resistance)below T*,in contrast to the increase(decrease)of the critical current(flux-flow resistance)above T* expected for Abrikosov vortices.Furthermore,when θ is larger than 0.5°,the flux-flow resistance and critical current have no anomalous behaviors across T*.These anomalous behaviors can be understood in terms of the distinct transition from the well-pinned Abrikosov vortices to the weakly-pinned Josephson vortices upon cooling,when the coherent length perpendicular to the FeAs layers ξ⊥ becomes shorter than half of the interlayer distance d/2.These experimental findings indicate the existence of intrinsic Josephson junctions below T* and thus quasi-two-dimensional superconductivity in Ca10(Pt3As8)((Fe0.9Pt0.1)2As2)5,similar to those in the cuprate superconductors.展开更多
The present study aims to explore the physico-chemical structure evolution characteristic during Yangchangwan bituminous coal(YCW)gasification in the presence of iron-based waste catalyst(IWC).The catalytic gasificati...The present study aims to explore the physico-chemical structure evolution characteristic during Yangchangwan bituminous coal(YCW)gasification in the presence of iron-based waste catalyst(IWC).The catalytic gasification reactivity of YCW was measured by thermogravimetric analyzer.Scanning electron microscope–energy dispersive system,nitrogen adsorption analyzer and laser Raman spectroscopy were employed to analyze the char physico-chemical properties.The results show that the optimal IWC loading ratio was 5 wt%at 1000°C.The distribution of IWC on char was uneven and Fe catalyst concentrated on the surface of some chars.The specific surface area of YCW gasified semi-char decreased significantly with the increase of gasification time.i.e.,the specific surface area reduced from 382 m2/g(0 min)to 192 m2/g(3 min),meanwhile,the number of micropores and mesopores decreased sharply at the late gasification stage.The carbon microcrystalline structure of YCW gasified semi-char was gradually destroyed with the increase of gasification time,and the microcrystalline structure with small size was gradually generated,resulting in the decreasing order degree of carbon microcrystalline structure.IWC can catalyze YCW gasification which could provide theoretical guidance for industrial solid waste recycling.展开更多
new surface infiltrating composite technique has been developed to obtain metal and ceramic composite layer on the surface of metal by traditional casting method. It has been shown that with the new method, a composit...new surface infiltrating composite technique has been developed to obtain metal and ceramic composite layer on the surface of metal by traditional casting method. It has been shown that with the new method, a composite layer with a thickness of 2-5 mm can be obtained. The ceramic particulates distribute uniformly in the matrix. The composite layer is very favorable to wear resistance and thermal resistance展开更多
With the increasing demand for lightweight and lower fuel consumption and safety of automobile industry, lightweight materials of high strength steel (HSS) are more and more widely used. The hot stamping technology, w...With the increasing demand for lightweight and lower fuel consumption and safety of automobile industry, lightweight materials of high strength steel (HSS) are more and more widely used. The hot stamping technology, which is determined by the inherent mechanical properties of high strength steel, makes molds prone to wear failure in the harsh service environments. In this paper, a finite element model is proposed for analyzing the value and distributions law of friction shear stress of contact surface of the pin disk. Through the simulation process of sliding wear, two kinds of different cladding materials of the pin specimens including H13 and Fe65, were experimented under three different loads by using the software ABAQUS. And then the pin-on- disk wear test at elevated temperature was conducted to verify the effectiveness of the simula-tion results. The results showed that the friction shear stress of pin with iron-based cladding and H13 steel was different under different loads, but the distribution was basically the same;the normal friction shear stress increased gradually along the direction of the pin movement, and the tangential shear stress increased gradually from the center of the pin to the outside of the circle;the value of the friction shear stress of the normal joints on the contact surface was periodically fluctuating in the whole dynamic analysis step, while it was basically stable in the tangential direction.展开更多
In 1937,Ettore Majorana,an Italian physicist,predicted an elementary particle called the Majorana Fermion,for which the particle is its own anti-particle.The Majorana Fermion in condensed matter physics is also known ...In 1937,Ettore Majorana,an Italian physicist,predicted an elementary particle called the Majorana Fermion,for which the particle is its own anti-particle.The Majorana Fermion in condensed matter physics is also known as the Majorana zero mode.Because Majorana zero modes obey non-Abel statistics,it holds a great promise for the realization of topological quantum computing,which has attracted widespread interest.展开更多
Increasing environmental pollution and shortage of conventional fossil fuels have made it urgent to develop renewable and clean energy sources. Electrocatalytic water splitting, with its abundant raw materials, simple...Increasing environmental pollution and shortage of conventional fossil fuels have made it urgent to develop renewable and clean energy sources. Electrocatalytic water splitting, with its abundant raw materials, simple process, and zero carbon emission, is considered one of the most promising processes for producing carbon-neutral hydrogen which has excellent energy conversion efficiency and high gravimetric energy density. Among them, oxygen evolution reaction (OER) electrocatalysts and hydrogen evolution reaction (HER) electrocatalysts are critical to decreasing the intrinsic reaction energy barrier and boosting the hydrogen evolution efficiency. Therefore, it is imperative to develop and design low-cost, highly active, and stable OER and HER electrocatalysts to lower the overpotential and drive the electrocatalytic reactions. Transition metal sulfides, especially iron-based sulfides, have attracted extensive exploration by researchers as a result of its high abundance in the Earth's crust and near-metallic conductivity. Consequently, in this review, we systematically and comprehensively summarize the progress in the application of iron-based sulfides and their composites as OER and HER electrocatalysts in electrocatalysis. Detailed descriptions and illustrations of the special relationships among their composition, structure, and electrocatalytic performance are presented. Finally, this review points out the challenges and future prospects of iron-based sulfides in practical applications for designing and fabricating more promising iron-based sulfide OER and HER electrocatalysts. We believe that iron-based sulfide materials will have a wide range of application prospects as OER and HER electrocatalysts in the future.展开更多
Capturing and utilizing CO_(2)from the production process is the key to solving the excessive CO_(2)emission problem. CO_(2)hydrogenation with green hydrogen to produce olefins is an effective and promising way to uti...Capturing and utilizing CO_(2)from the production process is the key to solving the excessive CO_(2)emission problem. CO_(2)hydrogenation with green hydrogen to produce olefins is an effective and promising way to utilize CO_(2)and produce valuable chemicals. The olefins can be produced by CO_(2)hydrogenation through two routes, i.e., CO_(2)-FTS (carbon dioxide Fischer- Tropsch synthesis) and MeOH (methanol-mediated), among which CO_(2)-FTS has significant advantages over MeOH in practical applications due to its relatively high CO_(2)conversion and low energy consumption potentials. However, the CO_(2)-FTS faces challenges of difficult CO_(2)activation and low olefins selectivity. Iron-based catalysts are promising for CO_(2)-FTS due to their dual functionality of catalyzing RWGS and CO-FTS reactions. This review summarizes the recent progress on iron-based catalysts for CO_(2)hydrogenation via the FTS route and analyzes the catalyst optimization from the perspectives of additives, active sites, and reaction mechanisms. Furthermore, we also outline principles and challenges for rational design of high-performance CO_(2)-FTS catalysts.展开更多
Lithium-sulfur(Li-S)battery has been considered as one of the most promising next generation energy storage technologies for its overwhelming merits of high theoretical specific capacity(1673 m Ah/g),high energy densi...Lithium-sulfur(Li-S)battery has been considered as one of the most promising next generation energy storage technologies for its overwhelming merits of high theoretical specific capacity(1673 m Ah/g),high energy density(2500 Wh/kg),low cost,and environmentally friendliness of sulfur.However,critical drawbacks,including inherent low conductivity of sulfur and Li2S,large volume changes of sulfur cathodes,undesirable shuttling and sluggish redox kinetics of polysulfides,seriously deteriorate the energy density,cycle life and rate capability of Li-S battery,and thus limit its practical applications.Herein,we reviewed the recent developments addressing these problems through iron-based nanomaterials for effective synergistic immobilization as well as conversion reaction kinetics acceleration for polysulfides.The mechanist configurations between different iron-based nanomaterials and polysulfides for entrapment and conversion acceleration were summarized at first.Then we concluded the recent progresses on utilizing various iron-based nanomaterials in Li-S battery as sulfur hosts,separators and cathode interlayers.Finally,we discussed the challenges and perspectives for designing high sulfur loading cathode architectures along with outstanding chemisorption capability and catalytic activity.展开更多
The conversion from syngas derived from non-petroleum recourses to liquid fuels and chemicals via Fischer–Tropsch synthesis(FTS)is regarded as an alternative and potential route.Developing catalyst with controllable ...The conversion from syngas derived from non-petroleum recourses to liquid fuels and chemicals via Fischer–Tropsch synthesis(FTS)is regarded as an alternative and potential route.Developing catalyst with controllable particle size and clarifying size effect are of significance to promote the process.Herein,we engineered carbon-encapsulation structure to restrict particle growth but avoid strong metal–support interactions.The prepared carbon-encapsulated nanoparticles(Fe@C)showed a superior catalytic activity compared with conventional carbon-supported nanoparticles(Fe/C).By tuning particle size from 3.0 to 9.1 nm,a volcano-like trend of iron time yield(FTY)peaked at 2659μmol·gFe^(−1)·s^(−1)is obtained with an optimum particle size of 5.3 nm.According to temperature-programmed reduction and desorption results,a linear relationship between apparent turnover frequency and CO dissociation capacity was established.The enhanced CO dissociative adsorption along with weakened H_(2)activation on larger nanoparticles resulted in higher C_(5+)selectivity.This study provides a strategy to synthesize carbon supported metal catalysts with controllable particle size and insight into size effect on Fe-based catalytic FTS.展开更多
With a series of recent breakthroughs,iron-based superconductors(FeSC)with a topological Dirac surface state are becoming a promising material platform for hosting Majorana zero modes,which we refer to as the iron-Maj...With a series of recent breakthroughs,iron-based superconductors(FeSC)with a topological Dirac surface state are becoming a promising material platform for hosting Majorana zero modes,which we refer to as the iron-Majorana platform.This platform uniquely combines high-Tcsuperconductivity,a topological band structure,and electron correlations into a single material,successfully avoiding the difficulties of achieving intrinsic p-wave topological superconductors and superconductor/topological insulator heterojunction systems.The most important advantages of the iron-Majorana platform are its wide topological region and large quasiparticle gap,which provide strong topological protection for pure Majorana zero modes(MZMs).When the superconductor/topological insulator heterojunction systems,e.g.,In As/Al nanowire,have the controversies of being trivial Majorana-like states,the iron-Majorana platform,which possesses well-understood physics and clear experimental evidence of vortex MZMs,is more likely to be a true MZM.However,unlike the nanowire Majorana systems with clear theoretical proposals for braiding schemes,the iron-Majorana system has no concrete method for exchanging the vortex MZMs or constructing a topological qubit.In this article,we propose a roadmap of the future efforts required for more physical exploration and achieving the non-Abelian exchange statistics of MZMs based on the iron-Majorana platform.展开更多
Macrophage polarization is an essential process involved in immune regulation.In response to different microenvironmental stimulation,macrophages polarize into cells with different phenotypes and functions,most typica...Macrophage polarization is an essential process involved in immune regulation.In response to different microenvironmental stimulation,macrophages polarize into cells with different phenotypes and functions,most typically M1(pro-inflammatory)and M2(anti-inflammatory)macrophages.Iron-based nanoparticles have been widely explored and reported to regulatemacrophage polarization for various biomedical applications.However,the influence factors and modulation mechanisms behind are complicated and not clear.In this review,we systemically summarized different iron-based nanoparticles that regulate macrophage polarization and function and discussed the influence factors and mechanisms underlying the modulation process.This review aims to deepen the understanding of the modulation of macrophage polarization by iron-based nanoparticles and expects to provide evidence and guidance for subsequent design and application of iron-based nanoparticles with specific macrophage modulation functions.展开更多
基金supported by Thailand Science Research and Innovation Fund Chulalongkorn University,Thailand(IND66210014)。
文摘Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of hydrogen sulfide(SOH_(2)S) to elemental sulfur(S) has emerged as a sustainable and environmentally friendly solution.Due to its unique properties,iron oxide has been extensively investigated as a catalyst for SOH_(2)S;however,rapid deactivation has remained a significant drawback.The causes of iron oxide-based catalysts deactivation mechanisms in SOH_(2)S,including sulfur or sulfate deposition,the transformation of iron species,sintering and excessive oxygen vacancy formation,and active site loss,are thoroughly examined in this review.By focusing on the deactivation mechanisms,this review aims to provide valuable insights into enhancing the stability and efficiency of iron-based catalysts for SOH_(2)S.
基金The authors acknowledge the support of the Shenyang University of Technology(QNPY202209-4)the National Natural Science Foundation of China(21571132)+1 种基金Jiangsu University Advanced Talent Fund(5501710002)the Education Department of Liaoning Province(JYTQN2023285).
文摘Anode materials are an essential part of lithium-ion batteries(LIBs),which determine the performance and safety of LIBs.Currently,graphite,as the anode material of commercial LIBs,is limited by its low theoretical capacity of 372 mA·h·g^(−1),thus hindering further development toward high-capacity and large-scale applications.Alkaline earth metal iron-based oxides are considered a promising candidate to replace graphite because of their low preparation cost,good thermal stability,superior stability,and high electrochemical performance.Nonetheless,many issues and challenges remain to be addressed.Herein,we systematically summarize the research progress of alkaline earth metal iron-based oxides as LIB anodes.Meanwhile,the material and structural properties,synthesis methods,electrochemical reaction mechanisms,and improvement strategies are introduced.Finally,existing challenges and future research directions are discussed to accelerate their practical application in commercial LIBs.
基金Project supported by CAS-Shanghai Science Research Center,China(Grant No.CAS-SSRC-YH-2015-01)the National Key R&D Program of China(Grant No.2017YFA0305400)+4 种基金the National Natural Science Foundation of China(Grant Nos.11674229,11227902,and 11604207)the EPSRC Platform Grant(Grant No.EP/M020517/1)Hefei Science Center,Chinese Academy of Sciences(Grant No.2015HSC-UE013)Science and Technology Commission of Shanghai Municipality,China(Grant No.14520722100)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB04040200)。
文摘Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,FeS,the least studied Fe X compound(due to the difficulty in synthesizing high quality macroscopic crystals)attracted much attention because of its puzzling superconducting pairing symmetry.In this work,combining scanning tunneling microscopy and angle resolved photoemission spectroscopy(ARPES)with sub-micron spatial resolution,we investigate the intrinsic electronic structures of superconducting FeS from individual single crystalline domains.Unlike FeTe or FeSe,FeS remains identical tetragonal structure from room temperature down to 5 K,and the band structures observed can be well reproduced by our ab-initio calculations.Remarkably,mixed with the 1×1 tetragonal metallic phase,we also observe the coexistence of √5×√5 reconstructed insulating phase in the crystal,which not only helps explain the unusual properties of FeS,but also demonstrates the importance of using spatially resolved experimental tools in the study of this compound.
基金Supported by the Special Funds for Major State Basic Research Projects( No.G19990 64 80 0 ),the National NaturalScience Foundation of China( No.2 973 4141) ,and SKL EP ( 0 0 62 ) ,SINOPEC and CNPC.
文摘Polynorbornenes were synthesized in the presence of an iron based catalyst, 2,6-bis[1-（2,6-diisopropyl-phenylimino）ethyl]pyridine iron（Ⅱ） dichloride. The FTIR, 1H NMR and 13C NMR analysis results revealed that the structure of the obtained polynorbornenes consisted of vinyl addition polymer substructures without any ring-opening structures. The polymers were amorphous with a short-range order, displayed in the WAXD（wide angle X-ray diffraction） diagrams. The glass transition temperatures ranged from 200 to 400 ℃. The effects of the polymerization reaction conditions, such as Al/Fe molar ratio and toluene/CH2Cl2 volume ratio, on the activity, intrinsic viscosity and Tg were also studied.
基金supported by the Ministry of Science and Technology of China (Grant No. 2019YFA0308500)the Chinese Academy of Sciences (Grant Nos. XDB28000000 and YSBR-003)。
文摘Majorana zero modes(MZMs) are Majorana-fermion-like quasiparticles existing in crystals or hybrid platforms with topologically non-trivial electronic structures. They obey non-Abelian braiding statistics and are considered promising to realize topological quantum computing. Discovery of MZM in the vortices of the iron-based superconductors(IBSs)has recently fueled the Majorana research in a way which not only removes the material barrier requiring construction of complicated hybrid artificial structures, but also enables observation of pure MZMs under higher temperatures. So far,MZMs have been observed in iron-based superconductors including FeTe_(0.55)Se_(0.45),(Li_(0.84)Fe_(0.16))OHFe Se, Ca KFe_(4)As_(4),and Li Fe As. In this topical review, we present an overview of the recent STM studies on the MZMs in IBSs. We start with the observation of MZMs in the vortices in FeTe_(0.55)Se_(0.45)and discuss the pros and cons of FeTe_(0.55)Se_(0.45) compared with other platforms. We then review the following up discovery of MZMs in vortices of Ca KFe_(4)As_(4), impurity-assisted vortices of Li Fe As, and quantum anomalous vortices in FeTe_(0.55)Se_(0.45), illustrating the pathway of the developments of MZM research in IBSs. Finally, we give perspective on future experimental works in this field.
文摘1 INTRODUCTIONTemperature-Programmed Reduction(TPR)is widely used in the study of the reduc-tion properties of catalysts[1-4].It does not depend on any specific property exceptthe reducibility of the catalyst.Parameters of the TPR profile,such as peaktemperature,peak area and peak width,are capable of providing certain indications onthe original state of the reduced species,the interaction effects between active compo-nents and promoter or supporter,and other reduction properties of the catalyst.
基金National Natural Science Foundation of China(No.51775068)。
文摘In order to adapt to the high temperature and heavy load process environment of large forgings,a novel die with"fist-like"structure is designed.The“fist-like”die mainly consists of“skin”layer,“bone”layer and matrix.To obtain the material with good supportability and good bonding strength with the“skin”layer,iron-based alloys RMD248 and CN72 were selected to make the"bone"layer,and the properties were compared.In this paper,the"bone"layer and the"skin"layer(CHN327)were surfaced on 5CrNiMo matrix by wire arc additive manufacture(WAAM).Then,cyclic heating to 500℃and thermal compression with a maximum deformation of 30%were adapted to test the high temperature mechanical properties.The microstructure changes before and after thermal cycles and compressions were observed by optical microscopy(OM),X-ray diffraction(XRD),energy dispersive spectrometer(EDS)and scanning electron microscopy(SEM).The results show that CN72 has more carbides than RMD248 at the joint surface,which makes it easy to form brittle fracture at the joint.Mechanical properties were tested by using microhardness machine.Meanwhile,hot tensile tests were performed to study bonding strength between the“skin”layer and the“bone”layer.The results show that the RMD248 has stable microhardness distribution while the microhardness of CN72 decreases with the distance from the interface.And the ultimate tensile strength between CN72 and CHN327 is higher than RMD248 in the temperature range of 400-450℃.It can be inferred that CN72 has higher inter-layer wear resistance and RMD248 has more stable high temperature performance.
文摘Iron-plating technology used for restoration of axis parts was applied to the manufacture of diamond bits in this paper.The technology for electroplating diamond bit of iron matrix was mastered through repeated experiments and research.The productive practice indicated that the DC-electroplated iron matrix of diamond bit has high hardness and good diamond exposure ability;the drilling rate of electroplated iron-based diamond bit was 2 m/h when drilling in grade 9 granite and bit life can reach 44 m,which can satisfy the drilling production requirements.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0302903)the National Natural Science Foundation of China(Grant No.11974412).
文摘Modulated electronic state due to the layered crystal structures brings about moderate anisotropy of superconductivity in the iron-based superconductors and thus Abrikosov vortices are expected in the mixed state.However,based on the angular and temperature dependent transport measurements in iron-based superconductor Ca_(10)(Pt_(3)As_(8))((Fe_(0.9)Pt_(0.1))_(2)As_(2))_(5) with Tc(≌)12 K,we find clear evidences of a crossover from Abrikosov vortices to Josephson vortices at a crossover temperature T*(≌)7 K,when the applied magnetic field is parallel to the superconducting FeAs layers,i.e.,the angle between the magnetic field and the FeAs layers θ=0°.This crossover to Josephson vortices is demonstrated by an abnormal decrease(increase)of the critical current(flux-flow resistance)below T*,in contrast to the increase(decrease)of the critical current(flux-flow resistance)above T* expected for Abrikosov vortices.Furthermore,when θ is larger than 0.5°,the flux-flow resistance and critical current have no anomalous behaviors across T*.These anomalous behaviors can be understood in terms of the distinct transition from the well-pinned Abrikosov vortices to the weakly-pinned Josephson vortices upon cooling,when the coherent length perpendicular to the FeAs layers ξ⊥ becomes shorter than half of the interlayer distance d/2.These experimental findings indicate the existence of intrinsic Josephson junctions below T* and thus quasi-two-dimensional superconductivity in Ca10(Pt3As8)((Fe0.9Pt0.1)2As2)5,similar to those in the cuprate superconductors.
基金The present work was supported by the National Natural Science Foundation of China (21968024)the Project of Key Research Plan of Ningxia (2019BCH01001)The authors also gratefully thank Professor Junzhuo Fang for his help in taking SEM–EDS photos.
文摘The present study aims to explore the physico-chemical structure evolution characteristic during Yangchangwan bituminous coal(YCW)gasification in the presence of iron-based waste catalyst(IWC).The catalytic gasification reactivity of YCW was measured by thermogravimetric analyzer.Scanning electron microscope–energy dispersive system,nitrogen adsorption analyzer and laser Raman spectroscopy were employed to analyze the char physico-chemical properties.The results show that the optimal IWC loading ratio was 5 wt%at 1000°C.The distribution of IWC on char was uneven and Fe catalyst concentrated on the surface of some chars.The specific surface area of YCW gasified semi-char decreased significantly with the increase of gasification time.i.e.,the specific surface area reduced from 382 m2/g(0 min)to 192 m2/g(3 min),meanwhile,the number of micropores and mesopores decreased sharply at the late gasification stage.The carbon microcrystalline structure of YCW gasified semi-char was gradually destroyed with the increase of gasification time,and the microcrystalline structure with small size was gradually generated,resulting in the decreasing order degree of carbon microcrystalline structure.IWC can catalyze YCW gasification which could provide theoretical guidance for industrial solid waste recycling.
文摘new surface infiltrating composite technique has been developed to obtain metal and ceramic composite layer on the surface of metal by traditional casting method. It has been shown that with the new method, a composite layer with a thickness of 2-5 mm can be obtained. The ceramic particulates distribute uniformly in the matrix. The composite layer is very favorable to wear resistance and thermal resistance
文摘With the increasing demand for lightweight and lower fuel consumption and safety of automobile industry, lightweight materials of high strength steel (HSS) are more and more widely used. The hot stamping technology, which is determined by the inherent mechanical properties of high strength steel, makes molds prone to wear failure in the harsh service environments. In this paper, a finite element model is proposed for analyzing the value and distributions law of friction shear stress of contact surface of the pin disk. Through the simulation process of sliding wear, two kinds of different cladding materials of the pin specimens including H13 and Fe65, were experimented under three different loads by using the software ABAQUS. And then the pin-on- disk wear test at elevated temperature was conducted to verify the effectiveness of the simula-tion results. The results showed that the friction shear stress of pin with iron-based cladding and H13 steel was different under different loads, but the distribution was basically the same;the normal friction shear stress increased gradually along the direction of the pin movement, and the tangential shear stress increased gradually from the center of the pin to the outside of the circle;the value of the friction shear stress of the normal joints on the contact surface was periodically fluctuating in the whole dynamic analysis step, while it was basically stable in the tangential direction.
基金the Ministry of Science and Technology of China(2015CB921000,2015CB921300,2016YFA0202300)the National Natural Science Foundation of China(11234014,61888102)CAS(XDB28000000,XDB07000000,112111KYSB20160061).
文摘In 1937,Ettore Majorana,an Italian physicist,predicted an elementary particle called the Majorana Fermion,for which the particle is its own anti-particle.The Majorana Fermion in condensed matter physics is also known as the Majorana zero mode.Because Majorana zero modes obey non-Abel statistics,it holds a great promise for the realization of topological quantum computing,which has attracted widespread interest.
基金the National Natural Science Foundation of China(No.22275052)the Natural Science Foundation of Hubei Province(No.2019CFB569)。
文摘Increasing environmental pollution and shortage of conventional fossil fuels have made it urgent to develop renewable and clean energy sources. Electrocatalytic water splitting, with its abundant raw materials, simple process, and zero carbon emission, is considered one of the most promising processes for producing carbon-neutral hydrogen which has excellent energy conversion efficiency and high gravimetric energy density. Among them, oxygen evolution reaction (OER) electrocatalysts and hydrogen evolution reaction (HER) electrocatalysts are critical to decreasing the intrinsic reaction energy barrier and boosting the hydrogen evolution efficiency. Therefore, it is imperative to develop and design low-cost, highly active, and stable OER and HER electrocatalysts to lower the overpotential and drive the electrocatalytic reactions. Transition metal sulfides, especially iron-based sulfides, have attracted extensive exploration by researchers as a result of its high abundance in the Earth's crust and near-metallic conductivity. Consequently, in this review, we systematically and comprehensively summarize the progress in the application of iron-based sulfides and their composites as OER and HER electrocatalysts in electrocatalysis. Detailed descriptions and illustrations of the special relationships among their composition, structure, and electrocatalytic performance are presented. Finally, this review points out the challenges and future prospects of iron-based sulfides in practical applications for designing and fabricating more promising iron-based sulfide OER and HER electrocatalysts. We believe that iron-based sulfide materials will have a wide range of application prospects as OER and HER electrocatalysts in the future.
基金the National Natural Science Foundation of China-Outstanding Youth Foundation (No. 22322814)the National Natural Science Foundation of China (No. 22108144)the Natural Science Foundation of Shandong-Outstanding Youth Foundation (No. ZR2023YQ017)。
文摘Capturing and utilizing CO_(2)from the production process is the key to solving the excessive CO_(2)emission problem. CO_(2)hydrogenation with green hydrogen to produce olefins is an effective and promising way to utilize CO_(2)and produce valuable chemicals. The olefins can be produced by CO_(2)hydrogenation through two routes, i.e., CO_(2)-FTS (carbon dioxide Fischer- Tropsch synthesis) and MeOH (methanol-mediated), among which CO_(2)-FTS has significant advantages over MeOH in practical applications due to its relatively high CO_(2)conversion and low energy consumption potentials. However, the CO_(2)-FTS faces challenges of difficult CO_(2)activation and low olefins selectivity. Iron-based catalysts are promising for CO_(2)-FTS due to their dual functionality of catalyzing RWGS and CO-FTS reactions. This review summarizes the recent progress on iron-based catalysts for CO_(2)hydrogenation via the FTS route and analyzes the catalyst optimization from the perspectives of additives, active sites, and reaction mechanisms. Furthermore, we also outline principles and challenges for rational design of high-performance CO_(2)-FTS catalysts.
基金financially supported by National Natural Science Foundation of China(Nos.51702362 and 21875282)Natural Science Foundation of Hunan Province(Nos.2022JJ30663,2022JJ40551)+1 种基金Scientific Research Project of National University of Defense Technology(No.ZK19–27)Significant Independent Research Projects for Young Talents of College of Aerospace Science and Engineering,National University of Defense Technology。
文摘Lithium-sulfur(Li-S)battery has been considered as one of the most promising next generation energy storage technologies for its overwhelming merits of high theoretical specific capacity(1673 m Ah/g),high energy density(2500 Wh/kg),low cost,and environmentally friendliness of sulfur.However,critical drawbacks,including inherent low conductivity of sulfur and Li2S,large volume changes of sulfur cathodes,undesirable shuttling and sluggish redox kinetics of polysulfides,seriously deteriorate the energy density,cycle life and rate capability of Li-S battery,and thus limit its practical applications.Herein,we reviewed the recent developments addressing these problems through iron-based nanomaterials for effective synergistic immobilization as well as conversion reaction kinetics acceleration for polysulfides.The mechanist configurations between different iron-based nanomaterials and polysulfides for entrapment and conversion acceleration were summarized at first.Then we concluded the recent progresses on utilizing various iron-based nanomaterials in Li-S battery as sulfur hosts,separators and cathode interlayers.Finally,we discussed the challenges and perspectives for designing high sulfur loading cathode architectures along with outstanding chemisorption capability and catalytic activity.
基金the National Natural Science Foundation of China(No.U20A20124)the Program of Introducing Talents of Discipline to Universities(No.BP0618007)are gratefully acknowledged.
文摘The conversion from syngas derived from non-petroleum recourses to liquid fuels and chemicals via Fischer–Tropsch synthesis(FTS)is regarded as an alternative and potential route.Developing catalyst with controllable particle size and clarifying size effect are of significance to promote the process.Herein,we engineered carbon-encapsulation structure to restrict particle growth but avoid strong metal–support interactions.The prepared carbon-encapsulated nanoparticles(Fe@C)showed a superior catalytic activity compared with conventional carbon-supported nanoparticles(Fe/C).By tuning particle size from 3.0 to 9.1 nm,a volcano-like trend of iron time yield(FTY)peaked at 2659μmol·gFe^(−1)·s^(−1)is obtained with an optimum particle size of 5.3 nm.According to temperature-programmed reduction and desorption results,a linear relationship between apparent turnover frequency and CO dissociation capacity was established.The enhanced CO dissociative adsorption along with weakened H_(2)activation on larger nanoparticles resulted in higher C_(5+)selectivity.This study provides a strategy to synthesize carbon supported metal catalysts with controllable particle size and insight into size effect on Fe-based catalytic FTS.
基金supported by the National Natural Science Foundation of China(Grant No.11888101)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB28000000)。
文摘With a series of recent breakthroughs,iron-based superconductors(FeSC)with a topological Dirac surface state are becoming a promising material platform for hosting Majorana zero modes,which we refer to as the iron-Majorana platform.This platform uniquely combines high-Tcsuperconductivity,a topological band structure,and electron correlations into a single material,successfully avoiding the difficulties of achieving intrinsic p-wave topological superconductors and superconductor/topological insulator heterojunction systems.The most important advantages of the iron-Majorana platform are its wide topological region and large quasiparticle gap,which provide strong topological protection for pure Majorana zero modes(MZMs).When the superconductor/topological insulator heterojunction systems,e.g.,In As/Al nanowire,have the controversies of being trivial Majorana-like states,the iron-Majorana platform,which possesses well-understood physics and clear experimental evidence of vortex MZMs,is more likely to be a true MZM.However,unlike the nanowire Majorana systems with clear theoretical proposals for braiding schemes,the iron-Majorana system has no concrete method for exchanging the vortex MZMs or constructing a topological qubit.In this article,we propose a roadmap of the future efforts required for more physical exploration and achieving the non-Abelian exchange statistics of MZMs based on the iron-Majorana platform.
基金supported by the National Natural Science Foundation of China(51832001,61821002)the Natural Science Foundation of Jiangsu Province(BK20220824,BK20222002)+1 种基金the National Key Research and Development Project(2021YFA1201403,2021YFA0716304)the Nanjing Science and technology development Foundation(202205066).
文摘Macrophage polarization is an essential process involved in immune regulation.In response to different microenvironmental stimulation,macrophages polarize into cells with different phenotypes and functions,most typically M1(pro-inflammatory)and M2(anti-inflammatory)macrophages.Iron-based nanoparticles have been widely explored and reported to regulatemacrophage polarization for various biomedical applications.However,the influence factors and modulation mechanisms behind are complicated and not clear.In this review,we systemically summarized different iron-based nanoparticles that regulate macrophage polarization and function and discussed the influence factors and mechanisms underlying the modulation process.This review aims to deepen the understanding of the modulation of macrophage polarization by iron-based nanoparticles and expects to provide evidence and guidance for subsequent design and application of iron-based nanoparticles with specific macrophage modulation functions.
