AIM:To investigate the effects of shortening the duration of silicone oil tamponade on retinal structure and function in patients undergoing silicone oil removal(SOR)after surgery for primary rhegmatogenous retinal de...AIM:To investigate the effects of shortening the duration of silicone oil tamponade on retinal structure and function in patients undergoing silicone oil removal(SOR)after surgery for primary rhegmatogenous retinal detachment(RRD).METHODS:A total of 58 eligible patients were enrolled and randomly assigned to two groups based on tamponade duration:the short-term group(30-45d)and the conventional group(≥90d).Comprehensive evaluations were performed before and after SOR,including slitlamp examination,best-corrected visual acuity(BCVA)measurement,intraocular pressure(IOP)testing,optical coherence tomography(OCT),optical coherence tomography angiography(OCTA),microperimetry,electroretinography(ERG),and visual evoked potential(VEP)assessment.RESULTS:A total of 33 patients(23 males and 10 females;33 eyes)were enrolled in the short-term SO tamponade group with mean age of 52.45±9.35y,and 25 patients(15 males and 10 females;25 eyes)were enrolled in the conventional SO tamponade group with mean age of 50.80±12.06y.Compared with the conventional group,the short-term silicone oil tamponade group had a significantly lower incidence of silicone oil emulsification and cataract progression,with no significant difference in retinal reattachment success rate.Structurally,short-term tamponade was associated with increased thickness of the retinal ganglion cell layer(RGCL)in the nasal and superior macular regions and improved recovery of superficial retinal vascular density in these areas.Functionally,the shortterm group showed better BCVA and retinal sensitivity both before and 1mo after SOR;additionally,the P100 amplitude in VEP tests was significantly increased in this group.CONCLUSION:Shortening the duration of silicone oil tamponade effectively reduces damage to retinal structure and function without compromising the success rate of retinal reattachment in patients with primary RRD.展开更多
Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'...Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.展开更多
The therapeutic efficacy of traditional Chinese medicine has been widely acknowledged due to its extensive history of clinical effectiveness.However,the precise active components underlying each prescription remain in...The therapeutic efficacy of traditional Chinese medicine has been widely acknowledged due to its extensive history of clinical effectiveness.However,the precise active components underlying each prescription remain incompletely understood.Polysaccharides,as a major constituent of water decoctions—the most common preparation method for Chinese medicinals—may provide a crucial avenue for deepening our understanding of the efficacy principles of Chinese medicine and establishing a framework for its modern development.The structural complexity and diversity of Chinese herbal polysaccharides present significant challenges in their separation and analysis compared to small molecules.This paper aims to explore the potential of Chinese herbal polysaccharides efficiently by briefly summarizing recent advancements in polysaccharide chemical research,focusing on methods of acquisition,structure elucidation,and quality control.展开更多
Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and...Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.展开更多
To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content ...To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.展开更多
In response to the urgent demand for lightweight,magnesium(Mg)alloys have garnered considerable attention owing to their low density.Nonetheless,the intrinsic poor room-temperature formability of Mg alloys remains a m...In response to the urgent demand for lightweight,magnesium(Mg)alloys have garnered considerable attention owing to their low density.Nonetheless,the intrinsic poor room-temperature formability of Mg alloys remains a major obstacle in shaping precise complex components,necessitating the development of superplastic Mg alloys.Excellent superplasticity is usually acquired in high-alloyed Mg alloys with enhanced microstructural thermal stability facilitated by abundant optimized second-phase particles.While for cost-effective low-alloyed Mg alloys lacking particles,regulating solute segregation has emerged as a promising approach to achieve superplasticity recently.Moreover,the potential of bimodal-grained Mg alloys for superplastic deformation has been revealed,expanding the options for designing superplastic materials beyond the conventional approach of fine-grained microstructures.This study reviews significant developments in superplastic Mg alloys from the view of alloying strategies,grain structure control and deformation mechanisms,with potential implications for future research and industrial applications of superplastic Mg alloys.展开更多
Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes...Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes with SiO_(2)and Al_(2)O_(3)ratios were investigated using various techniques.It is found that when SiO_(2)is replaced by Al_(2)O_(3),the Q^(4) to Q^(3) transition of silicon-oxygen network decreases while the aluminum-oxygen network increases,which result in the transformation of Si-O-Si bonds to Si-O-Al bonds and an increase in glass network connectivity even though the intermolecular bond strength decreases.The glass transition temperature(T_(g))increases continuously,while the thermal expansion coefficient increases and high-temperature viscosity first decreases and then increases.Meanwhile,the elastic modulus values increase from 93 to 102 GPa.This indicates that the elastic modulus is mainly affected by packing factor and dissociation energy,and elements with higher packing factors and dissociation energies supplant those with lower values,resulting in increased rigidity within the glass.展开更多
To investigate the pore structure of graphene oxide modified polymer cement mortar(GOPM)under salt-freeze-thaw(SFT)coupling effects and its impact on deterioration,this study modifies polymer cement mortar(EMCM)with g...To investigate the pore structure of graphene oxide modified polymer cement mortar(GOPM)under salt-freeze-thaw(SFT)coupling effects and its impact on deterioration,this study modifies polymer cement mortar(EMCM)with graphene oxide(GO).The micro-pore structure of GOPM is characterized using LF-NMR and SEM.Fractal theory is applied to calculate the fractal dimension of pore volume,and the deterioration patterns are analyzed based on the evolution characteristics of capillary pores.The experimental results indicate that,after 25 salt-freeze-thaw cycles(SFTc),SO2-4 ions penetrate the matrix,generating corrosion products that fill existing pores and enhance the compactness of the specimen.As the number of cycles increases,the ongoing formation and expansion of corrosion products within the matrix,combined with persistent freezing forces,and result in the degradation of the pore structure.Therefore,the mass loss rate(MLR)of the specimens shows a trend of first decreasing and then increasing,while the relative dynamic elastic modulus(RDEM)initially increases and then decreases.Compared to the PC group specimens,the G3PM group specimens show a 28.71% reduction in MLR and a 31.42% increase in RDEM after 150 SFTc.The fractal dimensions of the transition pores,capillary pores,and macropores in the G3PM specimens first increase and then decrease as the number of SFTc increases.Among them,the capillary pores show the highest correlation with MLR and RDEM,with correlation coefficients of 0.97438 and 0.98555,respectively.展开更多
Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is p...Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.展开更多
Bilinear structures are common in boost converters,and despite presenting interesting complexity,there are controls that have found general solutions under certain restrictions.Among these,the passive controls contain...Bilinear structures are common in boost converters,and despite presenting interesting complexity,there are controls that have found general solutions under certain restrictions.Among these,the passive controls containing the error dynamics of boost converters for a certain output structure are notable.While passive controls based on passivity demonstrate adequate performance,this work proposes a perturbation control based on the antisymmetric structure of boost converters to achieve better performance in terms of convergence speed and mean square error.Additionally,the perturbation control requires less error information for constructing the control signal,because it does not need information from all states or the entire passive output.Besides,the perturbation control uses the passivity of boost converters to ensure its stability.And finally,the perturbation control is compared with passive controls in a boost converter.展开更多
Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol ...Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.展开更多
The recovery and utilization of ubiquitous low-grade heat are crucial for mitigating the fossil energy crisis.However,uncontrolled spontaneous heat dissipation limits its practical application.Inspired by skeletal mus...The recovery and utilization of ubiquitous low-grade heat are crucial for mitigating the fossil energy crisis.However,uncontrolled spontaneous heat dissipation limits its practical application.Inspired by skeletal muscle thermogenesis,we develop a compressible wood phase change gel with mechano-controlled heat release by infiltrating xylitol gel into wood aerogel.The xylitol gel can store recovered low-grade heat for at least 1 month by leveraging its inherent energy barrier.The hierarchically aligned lamellar structure of wood aerogel facilitates mechanical adaptation,hydrogen bond formation,and energy dissipation between the wood aerogel and the xylitol gel,increasing the compressive strength and toughness of wood phase change gel fivefold compared to xylitol gel.This enhancement effect enables repetitive contact-separation motions between the wood phase change gel and the substrate during radial compression,overcoming the energy barrier and releasing approximately 178.6 J g−1 of heat.As a proof-of-concept,the wood phase change gel serves as the hot side in a thermoelectric generator,providing about 2.13 W m^(−2) of clean electricity by the controlled utilization of recovered solar heat.This study presents a sustainable method to achieve off-grid electricity generation through the controlled utilization of recovered low-grade heat.展开更多
With the advent of in-wheel motors and corner modules,the structure of vehicle chassis subsystems has shifted from traditionally centralized to distributed.This review focuses on the distributed chassis system(DCS)equ...With the advent of in-wheel motors and corner modules,the structure of vehicle chassis subsystems has shifted from traditionally centralized to distributed.This review focuses on the distributed chassis system(DCS)equipped with corner modules.It first provides a comprehensive summary and description of the revolution of the structure and control methods of vehicle chassis systems(including driving,braking,suspension,and steering systems).Given that DCS integrates various chassis subsystems,this review moves beyond individual subsystem analysis and delves into the coordination of these subsystems at the vehicle level.It provides a detailed summary of the methods and architectures used for integrated coordination and control,ensuring that multiple subsystems can function seamlessly as an integrated whole.Finally,this review summarizes the latest distributed control architecture for DCS.It also examines current control theories in the fields of control and information technology for distributed systems,such as multi-agent systems and cyber-physical systems.Based on these two control approaches,a multi-domain cooperative control framework for DCS is proposed.展开更多
Coal pore parameters are closely related to macrolithotypes and coal structures,having a large influence over the gas potential and productivity of coalbed methane(CBM).The Middle Jurassic Xishanyao Formation,located ...Coal pore parameters are closely related to macrolithotypes and coal structures,having a large influence over the gas potential and productivity of coalbed methane(CBM).The Middle Jurassic Xishanyao Formation,located in the southern Junggar Basin of northwestern China,has geological conditions with rich CBM resources.The 46 Xishanyao coal samples gathered from the drilling cores and coal mines cover 4 types of macrolithotypes(bright coal 1,semi-bright coal 2,semi-dull coal 3,and dull coal 4)and 2 types of coal structures(primary coal I and cataclastic coal II).Based on a range of pore testing experiments and analytical methods,the dual effects of different macrolithotypes and coal structures on pore structures were intensely studied.The results showed that the specific surface area(SSA)and total pore volume(TPV)of coal samples increased gradually from bright to dull coals.For the same macrolithotypes,the SSA and TPV of the primary coals were lower than those of the cataclastic coals.Generally,the pore structures of bright and semi-bright coals are simpler when compared to semi-dull and dull coals with the same coal structure,whereas cataclastic coals have more complicated pore structure systems than primary coals with the same macrolithotypes.The bright and semi-bright coals have higher vitrinite contents and more endogenous fractures,whereas well-developed structural fractures were identified in cataclastic coals.Therefore,bright and semi-bright coals have better pore connectivity than semi-dull and dull coals with the same coal structure,the pore connectivity of cataclastic coals being slightly better than that of primary coals under the same macrolithotypes.In terms of the CBM adsorption conditions,the eight type samples formed a descending order:Ⅱ-4>I-4>Ⅱ-3>Ⅰ-3>Ⅱ-2>Ⅰ-2>Ⅱ-1>Ⅰ-1,while they ranked as follows when consideration was given to the CBM seepage capacities:II-2>Ⅱ-1>Ⅰ-2>Ⅰ-1>Ⅰ-3>Ⅰ-4>Ⅱ-3>Ⅱ-4.As a result,it could be determined that the bright and semi-bright coals had stronger adsorption capacities,whereas the cataclastic coals had better pore connectivity and seepage capacities.Pore structure characteristics should be analysed under the dual control of different macrolithotypes and coal structures,so that they can provide greater value for guiding CBM exploration and exploitation,as along for preventing underground gas accidents.展开更多
Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a pro...Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.展开更多
For deep prospects in the foreland thrust belt,southern Junggar Basin,NW China,there are uncertainties in factors controlling the structural deformation,distribution of paleo-structures and detachment layers,and distr...For deep prospects in the foreland thrust belt,southern Junggar Basin,NW China,there are uncertainties in factors controlling the structural deformation,distribution of paleo-structures and detachment layers,and distribution of major hydrocarbon source rocks.Based on the latest 3D seismic,gravity-magnetic,and drilling data,together with the results of previous structural physical simulation and discrete element numerical simulation experiments,the spatial distribution of pre-existing paleo-structures and detachment layers in deep strata of southern Junggar Basin were systematically characterized,the structural deformation characteristics and formation mechanisms were analyzed,the distribution patterns of multiple hydrocarbon source rock suites were clarified,and hydrocarbon accumulation features in key zones were reassessed.The exploration targets in deep lower assemblages with possibility of breakthrough were expected.Key results are obtained in three aspects.First,structural deformation is controlled by two-stage paleo-structures and three detachment layers with distinct lateral variations:the Jurassic layer(moderate thickness,wide distribution),the Cretaceous layer(thickest but weak detachment),and the Paleogene layer(thin but long-distance lateral thrusting).Accordingly,a four-layer composite deformation sequence was identified,and the structural genetic model with paleo-bulge controlling zonation by segments laterally and multiple detachment layers controlling sequence vertically.Second,the Permian source rocks show a distribution pattern with narrow trough(west),multiple sags(central),and broad basin(east),which is depicted by combining high-precision gravity-magnetic data and time-frequency electromagnetic data for the first time,and the Jurassic source rocks feature thicker mudstones in the west and rich coals in the east according to the reassessment.Third,two petroleum systems and a four-layer composite hydrocarbon accumulation model are established depending on the structural deformation strength,trap effectiveness and source-trap configuration.The southern Junggar Basin is divided into three segments with ten zones,and a hierarchical exploration strategy is proposed for deep lower assemblages in this region,that is,focusing on five priority zones,expanding to three potential areas,and challenging two high-risk targets.展开更多
Electrocatalytic conversion of carbon dioxide(CO_(2))offers an effective method of CO_(2)fixation to mitigate global warming and the energy crisis.However,for supported Ni single-atom catalysts(SACs),which are among t...Electrocatalytic conversion of carbon dioxide(CO_(2))offers an effective method of CO_(2)fixation to mitigate global warming and the energy crisis.However,for supported Ni single-atom catalysts(SACs),which are among the most promising candidates for this application,the relationship between Ni coordination structure and catalytic properties is still under strong debate.Here,we fabricated a series of Ni SACs through precise-engineering of anchor sites on nitrogen-doped carbon(NC)followed by Ni atom anchoring using atomic layer deposition.Among them,a Ni_(1)/NC SAC,with a coordination number(CN)of four but less pyridinic nitrogen(N_(pyri)),achieved over 90%faradaic efϐiciency for CO at potentials from-0.7 to-1.0 V and a mass activity of 6.5 A/mgNi at-0.78 V along with high stability,outperforming other Ni SACs with lower CN and more N_(pyri).Theoretical calculations of various three and four-coordinated Ni_(1)-NxCy structures revealed a linear correlation between the reaction Gibbs free energy for the potential-limiting step and the highest occupied molecular orbital(HOMO)position of Ni-3d orbitals,therein the four-coordinated Ni_(1)-N_(1)C_(3)with the highest HOMO position is identified as the active site for the electrocatalytic CO_(2)-to-CO process,in line with the experimental results.展开更多
Diradicaloid polycyclic hydrocarbons(PHs)own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics.Herein,we disclose precise fusion of B/O-heterocy...Diradicaloid polycyclic hydrocarbons(PHs)own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics.Herein,we disclose precise fusion of B/O-heterocycles onto PHs for control over their electronic structures and diradical properties.We designed and synthesized four B/O-containing diradicaloid isomers that feature the fluoreno[3,2-b]fluorene and fluoreno[2,1-a]fluoreneπ-skeletons,respectively.The precise B/O-heterocycle fusion modes along with the changed conjugation patterns lead to their modulated electronic structures and properties,such as diradical and aromatic structures,energy levels and band gaps,as well as magnetic,electrochemical and photophysical properties.Notably,the mode A may decrease the open-shell extent,whereas the mode B can enhance the diradical nature,leading to their well-tuned diradical characters in the range of0.46-0.70.Moreover,the mode A stabilizes the LUMOs and the mode B obviously increases the HOMO levels,which are remarkably contributed by the B and O atoms,respectively,further giving rise to the decreased band gaps and redshifted absorptions.This study clearly illustrates the electronic effects of B/O-heterocycle fusion on PHs and gains insight into B/O-type organic diradicaloids.These findings will provide an important guideline for the design of more fascinating heteroatom-containing diradicaloids.展开更多
The flow control at low Reynolds numbers is one of the most promising technologies in the field of aerodynamics,and it is also an important source of the innovation for novel aircraft.In this study,a new way of nonlin...The flow control at low Reynolds numbers is one of the most promising technologies in the field of aerodynamics,and it is also an important source of the innovation for novel aircraft.In this study,a new way of nonlinear flow control by interaction between two flexible flaps is proposed,and their flow control mechanism is studied employing the self-constructed immersed boundary-lattice Boltzmann-finite element method(IB-LB-FEM).The effects of the difference in material properties and flap length between the two flexible flaps on the nonlinear flow control of the airfoil are discussed.It is suggested that the relationship between the deformation of the two flexible flaps and the evolution of the vortex under the fluid-structure interaction(FSI).It is shown that the upstream flexible flap plays a key role in the flow control of the two flexible flaps.The FSI effect of the upstream flexible flap will change the unsteady flow behind it and affect the deformation of the downstream flexible flap.Two flexible flaps with different material properties and different lengths will change their own FSI characteristics by the induced vortex,effectively suppressing the flow separation on the airfoil’s upper surface.The interaction of two flexible flaps plays an extremely important role in improving the autonomy and adjustability of flow control.The numerical results will provide a theoretical basis and technical guidance for the development and application of a new flap passive control technology.展开更多
Hardenability significantly impacts the distortion of gear during heat treatment,correlated to the uniformity of solute distribution in steel matrix.The experimental analysis was conducted on the macrostructure,solute...Hardenability significantly impacts the distortion of gear during heat treatment,correlated to the uniformity of solute distribution in steel matrix.The experimental analysis was conducted on the macrostructure,solute distribution,dendrite structure,and rod hardenability of 20CrMnTiH gear steel in continuously cast blooms and hot roller rods.The evaluation approach by the standards for the hardenability of gear steel rods and the corresponding blooms was analyzed,and the inheritance mechanism from solidification segregation to hardenability fluctuation of gear steel was revealed.The results indicate that semi-macroscopic spot segregation located in the equiaxed zone exhibits larger size,higher solute enrichment,and worse solute homogeneity,leading to significant solute fluctuations in the blooms and hardenability fluctuation in the rods.By increasing the liquid steel superheat from 35 to 40℃,reducing the mold electromagnetic stirring from 300 to 100 A,and implementing the soft reduction(SR)of 7 mm at the solidification end,the equiaxed ratio of the strand decreased from 26.42%to 6.69%.Consequently,the solute fluctuation range and standard deviation decrease significantly in the transverse section,while the maximum segregation ratio,average fluctuation range,and average standard deviation of solutes C,Cr,and Mn in the spot segregation decrease at the same time.At the meanwhile,the equiaxed ratio of the rod decreased from 24.89%to 4.09%,and the structure of the hardenability detection zone was transformed from equiaxed crystals to columnar crystals.Furthermore,the solute fluctuation range and standard deviation in the transverse section decreased,while the homogeneity in spot segregation was also improved.The hardness difference of A and B surfaces at J9 and J15 positions was smaller than 2 HRC,meeting the qualification standard for hardenability.展开更多
基金Supported by the Key Science&Technology Project of Guangzhou(No.202103000045)the National Natural Science Foundation of China(No.82070972,No.82271093).
文摘AIM:To investigate the effects of shortening the duration of silicone oil tamponade on retinal structure and function in patients undergoing silicone oil removal(SOR)after surgery for primary rhegmatogenous retinal detachment(RRD).METHODS:A total of 58 eligible patients were enrolled and randomly assigned to two groups based on tamponade duration:the short-term group(30-45d)and the conventional group(≥90d).Comprehensive evaluations were performed before and after SOR,including slitlamp examination,best-corrected visual acuity(BCVA)measurement,intraocular pressure(IOP)testing,optical coherence tomography(OCT),optical coherence tomography angiography(OCTA),microperimetry,electroretinography(ERG),and visual evoked potential(VEP)assessment.RESULTS:A total of 33 patients(23 males and 10 females;33 eyes)were enrolled in the short-term SO tamponade group with mean age of 52.45±9.35y,and 25 patients(15 males and 10 females;25 eyes)were enrolled in the conventional SO tamponade group with mean age of 50.80±12.06y.Compared with the conventional group,the short-term silicone oil tamponade group had a significantly lower incidence of silicone oil emulsification and cataract progression,with no significant difference in retinal reattachment success rate.Structurally,short-term tamponade was associated with increased thickness of the retinal ganglion cell layer(RGCL)in the nasal and superior macular regions and improved recovery of superficial retinal vascular density in these areas.Functionally,the shortterm group showed better BCVA and retinal sensitivity both before and 1mo after SOR;additionally,the P100 amplitude in VEP tests was significantly increased in this group.CONCLUSION:Shortening the duration of silicone oil tamponade effectively reduces damage to retinal structure and function without compromising the success rate of retinal reattachment in patients with primary RRD.
文摘Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.
基金supported by the Science and Technology Development Fund,Macao SAR (Nos.0075/2022/A and028/2022/ITP)the Zhuhai Science and Technology Plan Project in the Social Development Field (No.2220004000117)the University of Macao (Nos.MYRG-GRG2023-00082-ICMS-UMDF/CPG2024-00011-ICMS)。
文摘The therapeutic efficacy of traditional Chinese medicine has been widely acknowledged due to its extensive history of clinical effectiveness.However,the precise active components underlying each prescription remain incompletely understood.Polysaccharides,as a major constituent of water decoctions—the most common preparation method for Chinese medicinals—may provide a crucial avenue for deepening our understanding of the efficacy principles of Chinese medicine and establishing a framework for its modern development.The structural complexity and diversity of Chinese herbal polysaccharides present significant challenges in their separation and analysis compared to small molecules.This paper aims to explore the potential of Chinese herbal polysaccharides efficiently by briefly summarizing recent advancements in polysaccharide chemical research,focusing on methods of acquisition,structure elucidation,and quality control.
基金National Natural Science Foundation of China(32201491)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)The authors extend their appreciation to the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-1101-02”.
文摘Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.
基金Supported by the Science and Technology Cooperation and Exchange special project of Cooperation of Shanxi Province(202404041101014)the Fundamental Research Program of Shanxi Province(202403021212333)+3 种基金the Joint Funds of the National Natural Science Foundation of China(U24A20555)the Lvliang Key R&D of University-Local Cooperation(2023XDHZ10)the Initiation Fund for Doctoral Research of Taiyuan University of Science and Technology(20242026)the Outstanding Doctor Funding Award of Shanxi Province(20242080).
文摘To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.
基金primarily supported by The National Natural Science Foundation of China(under Nos.52234009 and 52271103)Partial financial support came from the Program for the Central University Youth Innovation Team(No.419021423505)the Fundamental Research Funds for the Central Universities,JLU.
文摘In response to the urgent demand for lightweight,magnesium(Mg)alloys have garnered considerable attention owing to their low density.Nonetheless,the intrinsic poor room-temperature formability of Mg alloys remains a major obstacle in shaping precise complex components,necessitating the development of superplastic Mg alloys.Excellent superplasticity is usually acquired in high-alloyed Mg alloys with enhanced microstructural thermal stability facilitated by abundant optimized second-phase particles.While for cost-effective low-alloyed Mg alloys lacking particles,regulating solute segregation has emerged as a promising approach to achieve superplasticity recently.Moreover,the potential of bimodal-grained Mg alloys for superplastic deformation has been revealed,expanding the options for designing superplastic materials beyond the conventional approach of fine-grained microstructures.This study reviews significant developments in superplastic Mg alloys from the view of alloying strategies,grain structure control and deformation mechanisms,with potential implications for future research and industrial applications of superplastic Mg alloys.
基金Supported by the National Key Research Program(No.2024-1129-954-112)National Natural Science Foundation of China(No.52372033)Guangxi Science and Technology Major Program(No.AA24263054)。
文摘Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes with SiO_(2)and Al_(2)O_(3)ratios were investigated using various techniques.It is found that when SiO_(2)is replaced by Al_(2)O_(3),the Q^(4) to Q^(3) transition of silicon-oxygen network decreases while the aluminum-oxygen network increases,which result in the transformation of Si-O-Si bonds to Si-O-Al bonds and an increase in glass network connectivity even though the intermolecular bond strength decreases.The glass transition temperature(T_(g))increases continuously,while the thermal expansion coefficient increases and high-temperature viscosity first decreases and then increases.Meanwhile,the elastic modulus values increase from 93 to 102 GPa.This indicates that the elastic modulus is mainly affected by packing factor and dissociation energy,and elements with higher packing factors and dissociation energies supplant those with lower values,resulting in increased rigidity within the glass.
基金Funded by the National Natural Science Foundation of China(Nos.5226804252468035)。
文摘To investigate the pore structure of graphene oxide modified polymer cement mortar(GOPM)under salt-freeze-thaw(SFT)coupling effects and its impact on deterioration,this study modifies polymer cement mortar(EMCM)with graphene oxide(GO).The micro-pore structure of GOPM is characterized using LF-NMR and SEM.Fractal theory is applied to calculate the fractal dimension of pore volume,and the deterioration patterns are analyzed based on the evolution characteristics of capillary pores.The experimental results indicate that,after 25 salt-freeze-thaw cycles(SFTc),SO2-4 ions penetrate the matrix,generating corrosion products that fill existing pores and enhance the compactness of the specimen.As the number of cycles increases,the ongoing formation and expansion of corrosion products within the matrix,combined with persistent freezing forces,and result in the degradation of the pore structure.Therefore,the mass loss rate(MLR)of the specimens shows a trend of first decreasing and then increasing,while the relative dynamic elastic modulus(RDEM)initially increases and then decreases.Compared to the PC group specimens,the G3PM group specimens show a 28.71% reduction in MLR and a 31.42% increase in RDEM after 150 SFTc.The fractal dimensions of the transition pores,capillary pores,and macropores in the G3PM specimens first increase and then decrease as the number of SFTc increases.Among them,the capillary pores show the highest correlation with MLR and RDEM,with correlation coefficients of 0.97438 and 0.98555,respectively.
基金supported by National Natural Science Foundation of China(No.52025055 and 52275571)Basic Research Operation Fund of China(No.xzy012024024).
文摘Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.
基金supported by the Secretaría de Investigación y Posgrado(SIP),and the Comisión de Operacióny Fomento de Actividades Académicas(COFAA),both from the Instituto Politécnico Nacional(IPN)by the Secretaría de Ciencia,Humanidades,Tecnologíae Innovación(SECIHTI),México.
文摘Bilinear structures are common in boost converters,and despite presenting interesting complexity,there are controls that have found general solutions under certain restrictions.Among these,the passive controls containing the error dynamics of boost converters for a certain output structure are notable.While passive controls based on passivity demonstrate adequate performance,this work proposes a perturbation control based on the antisymmetric structure of boost converters to achieve better performance in terms of convergence speed and mean square error.Additionally,the perturbation control requires less error information for constructing the control signal,because it does not need information from all states or the entire passive output.Besides,the perturbation control uses the passivity of boost converters to ensure its stability.And finally,the perturbation control is compared with passive controls in a boost converter.
基金supported by the Key Technologies Research and Development Program(No.2022YFB3504102)the National Natural Science Foundation of China(Nos.22035009,22002050,and 22202087)+2 种基金the National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2020B01)Fuyang Normal University Open Fund(No.FSKFKT006D)the Postdoctoral Science Foundation of China(Nos.2022T150765 and 2020M683154).
文摘Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.
基金supported by the National Key R&D Program of China (2023YFD2201403)the National Natural Science Foundation of China (Grant Nos. 32171693, 32201482)+1 种基金the Heilongjiang Natural Science Foundation Outstanding Youth project (Grant No. YQ2022C002)College Students'Innovative Entrepreneurial Training Plan Program (202410225338)
文摘The recovery and utilization of ubiquitous low-grade heat are crucial for mitigating the fossil energy crisis.However,uncontrolled spontaneous heat dissipation limits its practical application.Inspired by skeletal muscle thermogenesis,we develop a compressible wood phase change gel with mechano-controlled heat release by infiltrating xylitol gel into wood aerogel.The xylitol gel can store recovered low-grade heat for at least 1 month by leveraging its inherent energy barrier.The hierarchically aligned lamellar structure of wood aerogel facilitates mechanical adaptation,hydrogen bond formation,and energy dissipation between the wood aerogel and the xylitol gel,increasing the compressive strength and toughness of wood phase change gel fivefold compared to xylitol gel.This enhancement effect enables repetitive contact-separation motions between the wood phase change gel and the substrate during radial compression,overcoming the energy barrier and releasing approximately 178.6 J g−1 of heat.As a proof-of-concept,the wood phase change gel serves as the hot side in a thermoelectric generator,providing about 2.13 W m^(−2) of clean electricity by the controlled utilization of recovered solar heat.This study presents a sustainable method to achieve off-grid electricity generation through the controlled utilization of recovered low-grade heat.
基金Supported by National Natural Science Foundation of China(Grant Nos.52072072,52025121,52394263).
文摘With the advent of in-wheel motors and corner modules,the structure of vehicle chassis subsystems has shifted from traditionally centralized to distributed.This review focuses on the distributed chassis system(DCS)equipped with corner modules.It first provides a comprehensive summary and description of the revolution of the structure and control methods of vehicle chassis systems(including driving,braking,suspension,and steering systems).Given that DCS integrates various chassis subsystems,this review moves beyond individual subsystem analysis and delves into the coordination of these subsystems at the vehicle level.It provides a detailed summary of the methods and architectures used for integrated coordination and control,ensuring that multiple subsystems can function seamlessly as an integrated whole.Finally,this review summarizes the latest distributed control architecture for DCS.It also examines current control theories in the fields of control and information technology for distributed systems,such as multi-agent systems and cyber-physical systems.Based on these two control approaches,a multi-domain cooperative control framework for DCS is proposed.
基金supported by the National Natural Science Foundation of China(Grant No.42102223)the Chinese Postdoctoral Science Foundation(Grant Nos.2021M693844,2022T150284)+1 种基金the Chinese Geological Survey Project(Grant No.DD20160204-3)the discipline innovation team of Liaoning Technical University(Grant Nos.LNTU20TD-14,LNTU20TD-30)。
文摘Coal pore parameters are closely related to macrolithotypes and coal structures,having a large influence over the gas potential and productivity of coalbed methane(CBM).The Middle Jurassic Xishanyao Formation,located in the southern Junggar Basin of northwestern China,has geological conditions with rich CBM resources.The 46 Xishanyao coal samples gathered from the drilling cores and coal mines cover 4 types of macrolithotypes(bright coal 1,semi-bright coal 2,semi-dull coal 3,and dull coal 4)and 2 types of coal structures(primary coal I and cataclastic coal II).Based on a range of pore testing experiments and analytical methods,the dual effects of different macrolithotypes and coal structures on pore structures were intensely studied.The results showed that the specific surface area(SSA)and total pore volume(TPV)of coal samples increased gradually from bright to dull coals.For the same macrolithotypes,the SSA and TPV of the primary coals were lower than those of the cataclastic coals.Generally,the pore structures of bright and semi-bright coals are simpler when compared to semi-dull and dull coals with the same coal structure,whereas cataclastic coals have more complicated pore structure systems than primary coals with the same macrolithotypes.The bright and semi-bright coals have higher vitrinite contents and more endogenous fractures,whereas well-developed structural fractures were identified in cataclastic coals.Therefore,bright and semi-bright coals have better pore connectivity than semi-dull and dull coals with the same coal structure,the pore connectivity of cataclastic coals being slightly better than that of primary coals under the same macrolithotypes.In terms of the CBM adsorption conditions,the eight type samples formed a descending order:Ⅱ-4>I-4>Ⅱ-3>Ⅰ-3>Ⅱ-2>Ⅰ-2>Ⅱ-1>Ⅰ-1,while they ranked as follows when consideration was given to the CBM seepage capacities:II-2>Ⅱ-1>Ⅰ-2>Ⅰ-1>Ⅰ-3>Ⅰ-4>Ⅱ-3>Ⅱ-4.As a result,it could be determined that the bright and semi-bright coals had stronger adsorption capacities,whereas the cataclastic coals had better pore connectivity and seepage capacities.Pore structure characteristics should be analysed under the dual control of different macrolithotypes and coal structures,so that they can provide greater value for guiding CBM exploration and exploitation,as along for preventing underground gas accidents.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074213,11574108,and 12104253)the National Key R&D Program of China(Grant No.2022YFA1403103)+2 种基金the Major Basic Program of the Natural Science Foundation of Shandong Province(Grant No.ZR2021ZD01)the Natural Science Foundation of Shandong Provincial(Grant No.ZR2023MA082)the Project of Introduction and Cultivation for Young Innovative Talents in Colleges and Universities of Shandong Province。
文摘Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.
基金Supported by the Science and Technology Special Project of CNPC(2023YQX10111)Key Research and Development Special Project of Xinjiang Uygur Autonomous Region(2024B01015-3)。
文摘For deep prospects in the foreland thrust belt,southern Junggar Basin,NW China,there are uncertainties in factors controlling the structural deformation,distribution of paleo-structures and detachment layers,and distribution of major hydrocarbon source rocks.Based on the latest 3D seismic,gravity-magnetic,and drilling data,together with the results of previous structural physical simulation and discrete element numerical simulation experiments,the spatial distribution of pre-existing paleo-structures and detachment layers in deep strata of southern Junggar Basin were systematically characterized,the structural deformation characteristics and formation mechanisms were analyzed,the distribution patterns of multiple hydrocarbon source rock suites were clarified,and hydrocarbon accumulation features in key zones were reassessed.The exploration targets in deep lower assemblages with possibility of breakthrough were expected.Key results are obtained in three aspects.First,structural deformation is controlled by two-stage paleo-structures and three detachment layers with distinct lateral variations:the Jurassic layer(moderate thickness,wide distribution),the Cretaceous layer(thickest but weak detachment),and the Paleogene layer(thin but long-distance lateral thrusting).Accordingly,a four-layer composite deformation sequence was identified,and the structural genetic model with paleo-bulge controlling zonation by segments laterally and multiple detachment layers controlling sequence vertically.Second,the Permian source rocks show a distribution pattern with narrow trough(west),multiple sags(central),and broad basin(east),which is depicted by combining high-precision gravity-magnetic data and time-frequency electromagnetic data for the first time,and the Jurassic source rocks feature thicker mudstones in the west and rich coals in the east according to the reassessment.Third,two petroleum systems and a four-layer composite hydrocarbon accumulation model are established depending on the structural deformation strength,trap effectiveness and source-trap configuration.The southern Junggar Basin is divided into three segments with ten zones,and a hierarchical exploration strategy is proposed for deep lower assemblages in this region,that is,focusing on five priority zones,expanding to three potential areas,and challenging two high-risk targets.
文摘Electrocatalytic conversion of carbon dioxide(CO_(2))offers an effective method of CO_(2)fixation to mitigate global warming and the energy crisis.However,for supported Ni single-atom catalysts(SACs),which are among the most promising candidates for this application,the relationship between Ni coordination structure and catalytic properties is still under strong debate.Here,we fabricated a series of Ni SACs through precise-engineering of anchor sites on nitrogen-doped carbon(NC)followed by Ni atom anchoring using atomic layer deposition.Among them,a Ni_(1)/NC SAC,with a coordination number(CN)of four but less pyridinic nitrogen(N_(pyri)),achieved over 90%faradaic efϐiciency for CO at potentials from-0.7 to-1.0 V and a mass activity of 6.5 A/mgNi at-0.78 V along with high stability,outperforming other Ni SACs with lower CN and more N_(pyri).Theoretical calculations of various three and four-coordinated Ni_(1)-NxCy structures revealed a linear correlation between the reaction Gibbs free energy for the potential-limiting step and the highest occupied molecular orbital(HOMO)position of Ni-3d orbitals,therein the four-coordinated Ni_(1)-N_(1)C_(3)with the highest HOMO position is identified as the active site for the electrocatalytic CO_(2)-to-CO process,in line with the experimental results.
基金supported by National Natural Science Foundation of China(Nos.52373182 and 22175074)Jilin Scientific and Technological Development Program(No.20220101054JC)Department of Education of Jilin Province(No.JJKH20221046KJ)。
文摘Diradicaloid polycyclic hydrocarbons(PHs)own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics.Herein,we disclose precise fusion of B/O-heterocycles onto PHs for control over their electronic structures and diradical properties.We designed and synthesized four B/O-containing diradicaloid isomers that feature the fluoreno[3,2-b]fluorene and fluoreno[2,1-a]fluoreneπ-skeletons,respectively.The precise B/O-heterocycle fusion modes along with the changed conjugation patterns lead to their modulated electronic structures and properties,such as diradical and aromatic structures,energy levels and band gaps,as well as magnetic,electrochemical and photophysical properties.Notably,the mode A may decrease the open-shell extent,whereas the mode B can enhance the diradical nature,leading to their well-tuned diradical characters in the range of0.46-0.70.Moreover,the mode A stabilizes the LUMOs and the mode B obviously increases the HOMO levels,which are remarkably contributed by the B and O atoms,respectively,further giving rise to the decreased band gaps and redshifted absorptions.This study clearly illustrates the electronic effects of B/O-heterocycle fusion on PHs and gains insight into B/O-type organic diradicaloids.These findings will provide an important guideline for the design of more fascinating heteroatom-containing diradicaloids.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.92371201,52192633,11872293,and 92152301)the Natural Science Basic Research Program of Shaanxi(Grant Nos.2024JC-YBQN-0008,and 2022JC-03)+1 种基金Shaanxi Key Research and Development Program(Grant No.2022ZDLGY02-07)the Joint Natural Science Foundation of China with Guangdong Province for TianHe-II Supercomputer Resources,and the Research Start-up Foundation of Xi’an University of Science and Technology for the High-Level Talent.
文摘The flow control at low Reynolds numbers is one of the most promising technologies in the field of aerodynamics,and it is also an important source of the innovation for novel aircraft.In this study,a new way of nonlinear flow control by interaction between two flexible flaps is proposed,and their flow control mechanism is studied employing the self-constructed immersed boundary-lattice Boltzmann-finite element method(IB-LB-FEM).The effects of the difference in material properties and flap length between the two flexible flaps on the nonlinear flow control of the airfoil are discussed.It is suggested that the relationship between the deformation of the two flexible flaps and the evolution of the vortex under the fluid-structure interaction(FSI).It is shown that the upstream flexible flap plays a key role in the flow control of the two flexible flaps.The FSI effect of the upstream flexible flap will change the unsteady flow behind it and affect the deformation of the downstream flexible flap.Two flexible flaps with different material properties and different lengths will change their own FSI characteristics by the induced vortex,effectively suppressing the flow separation on the airfoil’s upper surface.The interaction of two flexible flaps plays an extremely important role in improving the autonomy and adjustability of flow control.The numerical results will provide a theoretical basis and technical guidance for the development and application of a new flap passive control technology.
基金supported by the Weifang Science and Technology Development Plan Project in China(No.2023ZJ1166).
文摘Hardenability significantly impacts the distortion of gear during heat treatment,correlated to the uniformity of solute distribution in steel matrix.The experimental analysis was conducted on the macrostructure,solute distribution,dendrite structure,and rod hardenability of 20CrMnTiH gear steel in continuously cast blooms and hot roller rods.The evaluation approach by the standards for the hardenability of gear steel rods and the corresponding blooms was analyzed,and the inheritance mechanism from solidification segregation to hardenability fluctuation of gear steel was revealed.The results indicate that semi-macroscopic spot segregation located in the equiaxed zone exhibits larger size,higher solute enrichment,and worse solute homogeneity,leading to significant solute fluctuations in the blooms and hardenability fluctuation in the rods.By increasing the liquid steel superheat from 35 to 40℃,reducing the mold electromagnetic stirring from 300 to 100 A,and implementing the soft reduction(SR)of 7 mm at the solidification end,the equiaxed ratio of the strand decreased from 26.42%to 6.69%.Consequently,the solute fluctuation range and standard deviation decrease significantly in the transverse section,while the maximum segregation ratio,average fluctuation range,and average standard deviation of solutes C,Cr,and Mn in the spot segregation decrease at the same time.At the meanwhile,the equiaxed ratio of the rod decreased from 24.89%to 4.09%,and the structure of the hardenability detection zone was transformed from equiaxed crystals to columnar crystals.Furthermore,the solute fluctuation range and standard deviation in the transverse section decreased,while the homogeneity in spot segregation was also improved.The hardness difference of A and B surfaces at J9 and J15 positions was smaller than 2 HRC,meeting the qualification standard for hardenability.
