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
Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted dru...Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted drug delivery.For implants,mechanical properties are key performance characteristics,so understanding the deformation and failure mechanisms is essential for selecting the appropriate implant structure.The deformation and fracture processes in PLA samples with different interior architectures have been studied through computer simulation and experimental research.Two TPMS topologies,the Schwarz Diamond and Gyroid architectures,were used for the sample construction by 3D printing.ANSYS software was utilized to simulate compressive deformation.It was found that under the same load,the vonMises stresses in the Gyroid structure are higher than those in the Schwartz Diamond structure,which was associated with the different orientations of the cells in the studied structures in relation to the direction of the loading axis.The deformation process occurs in the local regions of the studied TPMS structures.Maximum von Mises stresses were observed in the vertical parts of the structures oriented along the load direction.It was found that,unlike the Gyroid,the Schwartz Diamond structure contains a frame that forms unique stiffening ribs,which ensures the redistribution of the load under the vertical loading direction.An analysis of the mechanical characteristics of PLA samples with the Schwartz Diamond and Gyroid structures produced by the Fused Deposition Modeling(FDM)method was correlated with computer simulation.The Schwarz Diamond-type structure was shown to have a higher absorption energy than the Gyroid one.A study of the fracture in PLA samples with various cell sizes revealed a particular feature related to the samples’periodic surface topology and the 3D printing process.Scanning electron microscopic(SEM)studies of the samples deformed by compression showed thatwith an increase in the density of the samples,the failure mechanism changes from ductile to quasi-brittle due to the complex participation of both cell deformation and fiber deformation.展开更多
4-Bromo-3-methylphenol(BMP)is an important chemical intermediate with wide applications in the fields of medicine and pesticides.The synthesis of BMP from m-cresol via bromination is easy to carry out on an industrial...4-Bromo-3-methylphenol(BMP)is an important chemical intermediate with wide applications in the fields of medicine and pesticides.The synthesis of BMP from m-cresol via bromination is easy to carry out on an industrial scale.However,due to the formation of regioisomeric impurities during bromination and the low melting point of BMP,the separation process is prone to the formation of oily substances,resulting in low yield and purity.In this work,a new cocrystallization engineering approach was proposed to separate and purify BMP.Through design of experiments,the cocrystallization process of BMP and triethylenediamine(DABCO)was optimized using a minimum-run resolution IV screening design combined with response surface methodology.In addition,the obtained 2BMP-DABCO powder was characterized by thermal analysis,powder X-ray diffraction,infrared spectroscopy,and scanning electron microscopy.Single crystals of 2BMP-DABCO were grown from acetone by slow evaporation,and detailed structural information was obtained through single-crystal X-ray diffraction.The self-assembly mechanism was further clarified by density functional theory calculations.This study provides a simple,robust,and scalable method for the production of BMP and offers a reference for the separation and purification of phenolic substances.展开更多
With superior structural integrity and design flexibility,3D woven fabrics exhibit unique potential in ballistic protection applications.However,the anisotropic yarn distribution renders traditional 3D woven fabrics s...With superior structural integrity and design flexibility,3D woven fabrics exhibit unique potential in ballistic protection applications.However,the anisotropic yarn distribution renders traditional 3D woven fabrics susceptible to fixed boundaries,which is not conducive to practical applications.Inspired by the motion characteristics of yarn structures,this study investigates a hybrid 3D woven fabric structure that incorporates interlayer warp yarns and normal yarns.Bending stiffness tests,yarn pull-out tests,and ballistic tests are conducted and compared with single-binding yarn structures.Utilizing a validated meso-finite element model,the dynamic deformation and energy absorption mechanisms of the hybrid configuration under impact are elucidated.The results demonstrate that synergistic interactions among various binding yarn structures maintain fabric stability in the absence of boundaries.Normal yarns inhibit horizontal slippage of warp yarns,while multi-layer warp yarns enhance resistance to weft yarn pull-out,thereby facilitating greater yarn participation in direct energy absorption.The hybrid structure exhibited the highest specific energy absorption(SEA)across different boundary conditions,with an average SEA increase of approximately 27%.These insights will facilitate the design of novel hybrid-structured 3D woven fabrics and inform the customization of lightweight protective materials.展开更多
Optimizing the oxygen reduction reaction(ORR)kinetics requires precise control of intermediate adsorption at active sites,which can be achieved through orbital engineering by regulating the electronic structure.This s...Optimizing the oxygen reduction reaction(ORR)kinetics requires precise control of intermediate adsorption at active sites,which can be achieved through orbital engineering by regulating the electronic structure.This study addresses the challenge by exploring how modulation of the 3d-orbital electronic structure of FeN_(4) active sites influences ORR electrocatalysis.To realize this,a catalyst composed of Fe_(3)C nanoparticles and FeN_(4) single atoms anchored on carbon black(Fe_(3)C-FeN_(4)/CB)was synthesized via a synergistic strategy of spatial confinement and atmosphere control.This unique heterostructure creates interfaces between Fe_(3)C and FeN_(4) that modulate the electronic configuration of the FeN_(4) center,transforming its geometry from square-planar to quasi-octahedral.Spectroscopic characterizations and theoretical calculations reveal that this orbital modulation results in a downward shift of the Fe dband center,altering the reaction pathway and lowering the energy barrier for ORR.Consequently,the Fe_(3)C-FeN_(4)/CB catalyst exhibits outstanding ORR activity,four-electron selectivity,excellent methanol tolerance,and remarkable electrochemical stability.When applied in a zinc-air battery,it achieves a peak power density of 178.4 mW cm^(-2)and superior cycling stability compared to commercial Pt/C catalysts.This work provides valuable insights into heterointerface-induced orbital modulation as a promising design principle for high-performance ORR electrocatalysts.展开更多
With the rapid advancement of optoelectronic technology,high-performance photodetectors are increasingly in demand in fields such as environmental monitoring,optical communication,and defense systems,where ultraviolet...With the rapid advancement of optoelectronic technology,high-performance photodetectors are increasingly in demand in fields such as environmental monitoring,optical communication,and defense systems,where ultraviolet detection is critical.However,conventional semiconductor materials suffer from limited UV-visible detection capabilities owing to their narrow bandgaps and high dark currents.To address these challenges,wide-bandgap semiconductors have emerged as promising alternatives.Here,we fabricated a horizontally structured n–n heterojunction photodetector by growingβ-Ga_(2)O_(3) on Si–GaN via plasma-enhanced chemical vapor deposition.The device exhibits a self-powered photocurrent of 3.5 nA at zero bias,enabled by the photovoltaic effect of the space charge region.Under 254-nm and 365-nm illumination,it exhibits rectification behavior,achieving a responsivity of 0.475 m A/W(0 V,220??W/cm~2 at 254 nm)and 257.6 mA/W(-5 V),respectively.Notably,the photodetector demonstrates a high photocurrent-to-dark current ratio of 10~5 under-5-V bias,highlighting its potential for self-powered and high-performance UV detection applications.展开更多
MgO has been shown to facilitate the precipitation of MgO-rich crystalline phases within the MgO-CaO-Al_(2)O_(3)-SiO_(2)(MCAS)glassy inclusion system,which possesses a high liquidus temperature and a significant Young...MgO has been shown to facilitate the precipitation of MgO-rich crystalline phases within the MgO-CaO-Al_(2)O_(3)-SiO_(2)(MCAS)glassy inclusion system,which possesses a high liquidus temperature and a significant Young’s modulus.The underlying linkage between the structural evolution and the crystallization characteristics of the MCAS system was systematically investigated using molecular dynamics simulation and thermodynamic calculation.The results revealed that Mg^(2+) ions played a dual role,constructing networks through the formation of tricluster oxygens while consuming bridging oxygens(BOs)in a mechanism similar to Ca^(2+) ions.However,despite this dual role,the network connectivity was still decreased with the increase in MgO/(MgO+Al_(2)O_(3))(M/(M+A))and CaO/(CaO+SiO_(2))(C/(C+S))ratios,primarily due to the reduction in BOs.This microscopic structural evolution resulted in a reduction in viscosity and an enhancement of crystallization ability.Furthermore,the remarkable diffusion capability of Mg^(2+) ions,coupled with the increased proportion of 6-coordinated Mg^(2+)ions,unveiled the mechanism underlying the precipitation of MgSiO_(3) and Mg_(2)SiO_(4) crystals,which exhibited high Young’s moduli of 165.23 and 196.67 GPa,respectively.To prevent the precipitation of MgO-rich crystalline phases,it was crucial to maintain the M/(M+A)ratio below 0.42 and the C/(C+S)ratio below 0.16 within the MCAS system.展开更多
The electronic structure,including band structure,density of states （DOS）, and partial density of states of SrTi1-xSbxO3 with x = 0,0. 125,0.25,and 0.33 is calculated from the first principles of plane wave ultra-so...The electronic structure,including band structure,density of states （DOS）, and partial density of states of SrTi1-xSbxO3 with x = 0,0. 125,0.25,and 0.33 is calculated from the first principles of plane wave ultra-soft pseudo-potential technology based on density function theory. The calculated results reveal that due to the electron doping,the Fermi level moves into the conduction bands for SrTi1-xSbxO3 with x = 0. 125 and the system shows metallic behavior. In addition, the DOS moves towards low energy and the optical band gap is broadened. The wide band gap and the low density of the states in the conduction band result in the transparency of the films.展开更多
The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the ...The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.展开更多
Mesh models are among the primary representations for storing 3-D objects,encapsulating detailed geometric information.3-D mesh watermarking,in particular,plays a central role in the protection of 3-D content.However,...Mesh models are among the primary representations for storing 3-D objects,encapsulating detailed geometric information.3-D mesh watermarking,in particular,plays a central role in the protection of 3-D content.However,frequency-domain methods rely on complex parameterization and spectral decomposition,which are sensitive to mesh topology and resolution and often introduce perceptible artifacts.Spatial-domain techniques,on the other hand,typically embed watermarks in global or randomly selected regions,leading to visible distortions and reduced robustness.To address the above limitations and protect model copyright without compromising the original aesthetic quality,we propose a deterministice PCA-synchronized 3Dmeshwatermarkingmethodwith fullerene-guided carrier selection.First,a deterministic principal component analysis(PCA)-based mesh synchronization algorithm is employed to align the models to a canonical pose.Next,a fullerene-inspired carrier selection strategy is employed to determine the watermark carriers,leveraging the structural characteristics of fullerene molecules to achieve a more rational and effective carrier selection.Finally,to balance the embedding strength and enhance visual quality,the watermark information is embedded using an APQIM(Adaptive Parity-Check Quantization Index Modulation)scheme.The experimental results show that our method can achieve high visual quality with scalable capacity and strong robustness compared with existing methods.The watermarking scheme can resist various attacks,including simplification,smoothing,Gaussian noise,translation,and rotation.展开更多
Conventional Tb^(3+)-doped phosphors typically suffer from concentration quenching once the doping level exceeds a critical threshold.Consequently,the development of Tb^(3+)phosphors with intrinsic resistance to conce...Conventional Tb^(3+)-doped phosphors typically suffer from concentration quenching once the doping level exceeds a critical threshold.Consequently,the development of Tb^(3+)phosphors with intrinsic resistance to concentration quenching has become a key research focus.In this work,we successfully synthesized KBi(MoO_(4))_(2):x Tb^(3+)(x=0-100 at%)(denoted as KBM:x Tb^(3+))phosphors via a high-temperature solid-state reaction.Remarkably,no concentration quenching was observed across the entire doping range.This anti-quenching behavior originates from the large Tb^(3+)-Tb^(3+)interionic distance(>5Å)inherent to the quasi-layered crystal structure,which effectively suppresses multipole-interaction-mediated energy migration.At full Tb^(3+)substitution(x=100 at%),the material undergoes a structural phase transition from the monoclinic KBM phase to the triclinicα-KTb(MoO_(4))_(2)(α-KTM)phase.Theα-KTM phosphor exhibits excellent thermal stability(activation energy=0.6129 eV)and a single-exponential decay profile,whereas KBM:x Tb^(3+)(x<100%)display double-exponential decay behaviors,attributed to dual energy transfer pathways.These findings provide new insights into the luminescence mechanisms of high-concentration rare-earth-doped systems and offer guidance for designing nextgeneration anti-quenching phosphors.展开更多
Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and hi...Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.展开更多
Western Yunnan is a region with intensive tectonic activity and serious earthquake risk. It is of significant importance to study three dimensional crustal structure of this region to understand the tectonic setting a...Western Yunnan is a region with intensive tectonic activity and serious earthquake risk. It is of significant importance to study three dimensional crustal structure of this region to understand the tectonic setting and disaster mechanism. Densification and digitalization of seismic networks in this region provides an opportunity to study the velocity structure with bulletin data. In this study, we collect P-wave data of 10 403 regional earthquakes recorded by 79 seismic stations from January 2008 to December 2010. In addition to first arrivals data （Pg with epieentral distance less than 200 km and Pn）, the Pg （or P） data with epicentral distance more than 200 km are also considered as later direct arrivals in the tomographic inversion. We also compare the quantity and the quality of the seismic data before 2010 and after 2010. The test results show that adding the follow-up Pg phase can effectively improve the inversion ability of crustal imaging, and quantity and the data quality are significantly improved since 2010. The tomographie results show that： （1） The Honghe fault zone, which is the major fault systems in this region, may cut through the entire crust, and the velocity contrasts between two sides at lower crust beneath the Honghe fault are estimated at higher than 10%, while the velocity difference below Nujiang fault zone extends only in the upper crust; （2） Most of the earthquakes in the region occurred at the interface of high-velocity media and low-velocity media, i.e., the areas with high velocity gradient, which has been validated in other areas.展开更多
The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the ...The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.展开更多
Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is deter...Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.展开更多
Combined multi-body dynamics with structural dynamics, a new discrete element with flexible connector, which is applicable for 3-D beam structures, is developed in this paper. Both the generalized elastic coefficient ...Combined multi-body dynamics with structural dynamics, a new discrete element with flexible connector, which is applicable for 3-D beam structures, is developed in this paper. Both the generalized elastic coefficient matrix of the flexible connector and the mass matrix of discrete element may be off-diagonal in a general case. The zero-length rigid element is introduced to simulate the node at which multiple elements are jointed together. It may also be effective when the axes of adjacent elements are not in the same line. The examples for eigenvalue calculation show that the model is successful. It can be extended to the geometric nonlinear response analysis.展开更多
By processing the CSND Rayleigh wave data with the matched filter FTAN technique, Rayleigh wave dispersion for southeast China is obtained. The 4°×4°S wave dispersion of the pure path is calculated usin...By processing the CSND Rayleigh wave data with the matched filter FTAN technique, Rayleigh wave dispersion for southeast China is obtained. The 4°×4°S wave dispersion of the pure path is calculated using random inversion scheme, and 3-D S wave velocity structure is set up. Incorporating the above-mentioned results with wide angle seismic sounding data, we studied structure framework and the extending of faults in this area, which demonstrates that the depth of Moho in South China varies from 30 to 40 km, shallower from west to east. The depth of Moho varies from 25 to 28 km for the offshore. The depth of the asthenosphere in upper mantle varies from 60 to 100 km. The depth difference of layers at the two sides of Tanlu fault is more than 10 km at the south part of the Yangtze River, and the fault extends downward more than 170 km. The fault exceeds the main land at Hainan Island and slips into the southern China Sea. Both Tanlu fault and the huge bend of gravity gradient anomaly are influenced by展开更多
The title complex [Sr3（pda）2（Hpda）2（H2O）2]n·2nH2O（H2pda = pyridine-2,6-dicar- boxylic acid） has been prepared under solvothermal conditions. It has been characterized by X-ray single-crystal diffraction, ...The title complex [Sr3（pda）2（Hpda）2（H2O）2]n·2nH2O（H2pda = pyridine-2,6-dicar- boxylic acid） has been prepared under solvothermal conditions. It has been characterized by X-ray single-crystal diffraction, IR and elemental analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 10.3795（8）, b = 9.2225（7）, c = 18.5726（14） , β = 104.377（2）o, V = 1722.2（2） 3, C28H22N4O20Sr3, Mr = 997.36, Z = 2, Dc = 1.923 g/cm3, μ = 4.722 mm-1, F（000） = 984, the final R = 0.0269 and wR = 0.0538. This complex possesses a 3-D structure which is constructed from 1-D chain motifs linked by carboxylate groups. The luminescent property of the title complex has been investigated.展开更多
A simultaneous inversion of earthquake relocation and three-dimensional crustal structure of P-wave velocity in central-western China (21癗~36癗, 98癊~112癊) were performed in this paper. The crustal P-wave velocity m...A simultaneous inversion of earthquake relocation and three-dimensional crustal structure of P-wave velocity in central-western China (21癗~36癗, 98癊~112癊) were performed in this paper. The crustal P-wave velocity model and earthquake relocation for this region are obtained using Pg and Sg phase readings of 9 988 earthquakes from 1992 to 1999 recorded at 193 seismic stations within central-western China by SPHYPIT90 and SPHREL3D90 programs. A lateral inhomogeneous structure of P-wave velocity in this region was obtained. Ob-vious contrast of P-wave velocities was revealed on both sides of active fault zones. Relocated epicenters of 6 459 events show clear lineation along active faults, which indicated a close correlation between seismicity and the active faults in this region. Focal depths of 82% relocated events ranged from 0 to 20 km, which is in good agreement with that from double-difference earthquake location algorithm.展开更多
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.
文摘Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted drug delivery.For implants,mechanical properties are key performance characteristics,so understanding the deformation and failure mechanisms is essential for selecting the appropriate implant structure.The deformation and fracture processes in PLA samples with different interior architectures have been studied through computer simulation and experimental research.Two TPMS topologies,the Schwarz Diamond and Gyroid architectures,were used for the sample construction by 3D printing.ANSYS software was utilized to simulate compressive deformation.It was found that under the same load,the vonMises stresses in the Gyroid structure are higher than those in the Schwartz Diamond structure,which was associated with the different orientations of the cells in the studied structures in relation to the direction of the loading axis.The deformation process occurs in the local regions of the studied TPMS structures.Maximum von Mises stresses were observed in the vertical parts of the structures oriented along the load direction.It was found that,unlike the Gyroid,the Schwartz Diamond structure contains a frame that forms unique stiffening ribs,which ensures the redistribution of the load under the vertical loading direction.An analysis of the mechanical characteristics of PLA samples with the Schwartz Diamond and Gyroid structures produced by the Fused Deposition Modeling(FDM)method was correlated with computer simulation.The Schwarz Diamond-type structure was shown to have a higher absorption energy than the Gyroid one.A study of the fracture in PLA samples with various cell sizes revealed a particular feature related to the samples’periodic surface topology and the 3D printing process.Scanning electron microscopic(SEM)studies of the samples deformed by compression showed thatwith an increase in the density of the samples,the failure mechanism changes from ductile to quasi-brittle due to the complex participation of both cell deformation and fiber deformation.
基金supported by the National Natural Science Foundation of China(22177011(R.Z.Qiao),21977012(R.Z.Qiao),and 21572018(C.Li))the National High-Level Hospital Clinical Research Funding(2023-NHLHCRF-YXHZ-ZRMS-02)the Joint Project of BRCBC(Biomedical Translational Engineering Research Center of BUCT-CJFH)(XK2020-06).
文摘4-Bromo-3-methylphenol(BMP)is an important chemical intermediate with wide applications in the fields of medicine and pesticides.The synthesis of BMP from m-cresol via bromination is easy to carry out on an industrial scale.However,due to the formation of regioisomeric impurities during bromination and the low melting point of BMP,the separation process is prone to the formation of oily substances,resulting in low yield and purity.In this work,a new cocrystallization engineering approach was proposed to separate and purify BMP.Through design of experiments,the cocrystallization process of BMP and triethylenediamine(DABCO)was optimized using a minimum-run resolution IV screening design combined with response surface methodology.In addition,the obtained 2BMP-DABCO powder was characterized by thermal analysis,powder X-ray diffraction,infrared spectroscopy,and scanning electron microscopy.Single crystals of 2BMP-DABCO were grown from acetone by slow evaporation,and detailed structural information was obtained through single-crystal X-ray diffraction.The self-assembly mechanism was further clarified by density functional theory calculations.This study provides a simple,robust,and scalable method for the production of BMP and offers a reference for the separation and purification of phenolic substances.
基金supports from National Key R&D Program for Young Scientists of China(No.2022YFC3080900)the opening project of State Key Laboratory of Explosion Science and Safety Protection,Beijing Institute of Technology(No.KFJJ25-25M).
文摘With superior structural integrity and design flexibility,3D woven fabrics exhibit unique potential in ballistic protection applications.However,the anisotropic yarn distribution renders traditional 3D woven fabrics susceptible to fixed boundaries,which is not conducive to practical applications.Inspired by the motion characteristics of yarn structures,this study investigates a hybrid 3D woven fabric structure that incorporates interlayer warp yarns and normal yarns.Bending stiffness tests,yarn pull-out tests,and ballistic tests are conducted and compared with single-binding yarn structures.Utilizing a validated meso-finite element model,the dynamic deformation and energy absorption mechanisms of the hybrid configuration under impact are elucidated.The results demonstrate that synergistic interactions among various binding yarn structures maintain fabric stability in the absence of boundaries.Normal yarns inhibit horizontal slippage of warp yarns,while multi-layer warp yarns enhance resistance to weft yarn pull-out,thereby facilitating greater yarn participation in direct energy absorption.The hybrid structure exhibited the highest specific energy absorption(SEA)across different boundary conditions,with an average SEA increase of approximately 27%.These insights will facilitate the design of novel hybrid-structured 3D woven fabrics and inform the customization of lightweight protective materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.22272105 and 22572118)Natural Science Foundation of Shanghai(Grant No.23ZR1423900)。
文摘Optimizing the oxygen reduction reaction(ORR)kinetics requires precise control of intermediate adsorption at active sites,which can be achieved through orbital engineering by regulating the electronic structure.This study addresses the challenge by exploring how modulation of the 3d-orbital electronic structure of FeN_(4) active sites influences ORR electrocatalysis.To realize this,a catalyst composed of Fe_(3)C nanoparticles and FeN_(4) single atoms anchored on carbon black(Fe_(3)C-FeN_(4)/CB)was synthesized via a synergistic strategy of spatial confinement and atmosphere control.This unique heterostructure creates interfaces between Fe_(3)C and FeN_(4) that modulate the electronic configuration of the FeN_(4) center,transforming its geometry from square-planar to quasi-octahedral.Spectroscopic characterizations and theoretical calculations reveal that this orbital modulation results in a downward shift of the Fe dband center,altering the reaction pathway and lowering the energy barrier for ORR.Consequently,the Fe_(3)C-FeN_(4)/CB catalyst exhibits outstanding ORR activity,four-electron selectivity,excellent methanol tolerance,and remarkable electrochemical stability.When applied in a zinc-air battery,it achieves a peak power density of 178.4 mW cm^(-2)and superior cycling stability compared to commercial Pt/C catalysts.This work provides valuable insights into heterointerface-induced orbital modulation as a promising design principle for high-performance ORR electrocatalysts.
基金Project supported by the Joints Fund of the National Natural Science Foundation of China(Grant No.U23A20349)the Young Scientists Fund of the National Natural Science Foundation of China(Grant Nos.62204126,62305171,62304113)。
文摘With the rapid advancement of optoelectronic technology,high-performance photodetectors are increasingly in demand in fields such as environmental monitoring,optical communication,and defense systems,where ultraviolet detection is critical.However,conventional semiconductor materials suffer from limited UV-visible detection capabilities owing to their narrow bandgaps and high dark currents.To address these challenges,wide-bandgap semiconductors have emerged as promising alternatives.Here,we fabricated a horizontally structured n–n heterojunction photodetector by growingβ-Ga_(2)O_(3) on Si–GaN via plasma-enhanced chemical vapor deposition.The device exhibits a self-powered photocurrent of 3.5 nA at zero bias,enabled by the photovoltaic effect of the space charge region.Under 254-nm and 365-nm illumination,it exhibits rectification behavior,achieving a responsivity of 0.475 m A/W(0 V,220??W/cm~2 at 254 nm)and 257.6 mA/W(-5 V),respectively.Notably,the photodetector demonstrates a high photocurrent-to-dark current ratio of 10~5 under-5-V bias,highlighting its potential for self-powered and high-performance UV detection applications.
基金support from the National Key R&D Program of China(Grant Nos.2023YFB3709900 and 2023YFB3709903)the National Natural Science Foundation of China(Grant Nos.52174293 and U22A20171)+1 种基金the High Steel Center(HSC)at North China University of TechnologyUniversity of Science and Technology Beijing(USTB).
文摘MgO has been shown to facilitate the precipitation of MgO-rich crystalline phases within the MgO-CaO-Al_(2)O_(3)-SiO_(2)(MCAS)glassy inclusion system,which possesses a high liquidus temperature and a significant Young’s modulus.The underlying linkage between the structural evolution and the crystallization characteristics of the MCAS system was systematically investigated using molecular dynamics simulation and thermodynamic calculation.The results revealed that Mg^(2+) ions played a dual role,constructing networks through the formation of tricluster oxygens while consuming bridging oxygens(BOs)in a mechanism similar to Ca^(2+) ions.However,despite this dual role,the network connectivity was still decreased with the increase in MgO/(MgO+Al_(2)O_(3))(M/(M+A))and CaO/(CaO+SiO_(2))(C/(C+S))ratios,primarily due to the reduction in BOs.This microscopic structural evolution resulted in a reduction in viscosity and an enhancement of crystallization ability.Furthermore,the remarkable diffusion capability of Mg^(2+) ions,coupled with the increased proportion of 6-coordinated Mg^(2+)ions,unveiled the mechanism underlying the precipitation of MgSiO_(3) and Mg_(2)SiO_(4) crystals,which exhibited high Young’s moduli of 165.23 and 196.67 GPa,respectively.To prevent the precipitation of MgO-rich crystalline phases,it was crucial to maintain the M/(M+A)ratio below 0.42 and the C/(C+S)ratio below 0.16 within the MCAS system.
文摘The electronic structure,including band structure,density of states （DOS）, and partial density of states of SrTi1-xSbxO3 with x = 0,0. 125,0.25,and 0.33 is calculated from the first principles of plane wave ultra-soft pseudo-potential technology based on density function theory. The calculated results reveal that due to the electron doping,the Fermi level moves into the conduction bands for SrTi1-xSbxO3 with x = 0. 125 and the system shows metallic behavior. In addition, the DOS moves towards low energy and the optical band gap is broadened. The wide band gap and the low density of the states in the conduction band result in the transparency of the films.
基金Key Project Process Mechanism and Prediction of Geological Hazards (2001CB711005-1-3) and State Key Basic Research Project Mechanism and Prediction of Continental Earthquakes (G1998040702). sponsored by the Ministry of Science and Techno
基金National Natural Science Foundation of China (40074010) and Natural Science Foundation of Gansu Province (ZS981-A25-011)
文摘The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant 62272331the Key Laboratory of Data Protection and Intelligent Management,Ministry of Education,Sichuan University and the Fundamental Research Funds for the Central Universities under Grant SCU2023D008.
文摘Mesh models are among the primary representations for storing 3-D objects,encapsulating detailed geometric information.3-D mesh watermarking,in particular,plays a central role in the protection of 3-D content.However,frequency-domain methods rely on complex parameterization and spectral decomposition,which are sensitive to mesh topology and resolution and often introduce perceptible artifacts.Spatial-domain techniques,on the other hand,typically embed watermarks in global or randomly selected regions,leading to visible distortions and reduced robustness.To address the above limitations and protect model copyright without compromising the original aesthetic quality,we propose a deterministice PCA-synchronized 3Dmeshwatermarkingmethodwith fullerene-guided carrier selection.First,a deterministic principal component analysis(PCA)-based mesh synchronization algorithm is employed to align the models to a canonical pose.Next,a fullerene-inspired carrier selection strategy is employed to determine the watermark carriers,leveraging the structural characteristics of fullerene molecules to achieve a more rational and effective carrier selection.Finally,to balance the embedding strength and enhance visual quality,the watermark information is embedded using an APQIM(Adaptive Parity-Check Quantization Index Modulation)scheme.The experimental results show that our method can achieve high visual quality with scalable capacity and strong robustness compared with existing methods.The watermarking scheme can resist various attacks,including simplification,smoothing,Gaussian noise,translation,and rotation.
基金supported by the Natural Science Research Project of Anhui Province Education Department for Excellent Young Scholars(Grant No.2024AH030007)the National Natural Science Foundation of China(Grant No.52202001)。
文摘Conventional Tb^(3+)-doped phosphors typically suffer from concentration quenching once the doping level exceeds a critical threshold.Consequently,the development of Tb^(3+)phosphors with intrinsic resistance to concentration quenching has become a key research focus.In this work,we successfully synthesized KBi(MoO_(4))_(2):x Tb^(3+)(x=0-100 at%)(denoted as KBM:x Tb^(3+))phosphors via a high-temperature solid-state reaction.Remarkably,no concentration quenching was observed across the entire doping range.This anti-quenching behavior originates from the large Tb^(3+)-Tb^(3+)interionic distance(>5Å)inherent to the quasi-layered crystal structure,which effectively suppresses multipole-interaction-mediated energy migration.At full Tb^(3+)substitution(x=100 at%),the material undergoes a structural phase transition from the monoclinic KBM phase to the triclinicα-KTb(MoO_(4))_(2)(α-KTM)phase.Theα-KTM phosphor exhibits excellent thermal stability(activation energy=0.6129 eV)and a single-exponential decay profile,whereas KBM:x Tb^(3+)(x<100%)display double-exponential decay behaviors,attributed to dual energy transfer pathways.These findings provide new insights into the luminescence mechanisms of high-concentration rare-earth-doped systems and offer guidance for designing nextgeneration anti-quenching phosphors.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(T2121004)Key Programme(52235007)National Outstanding Youth Foundation of China(52325504).
文摘Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.
基金supported by China National Special Fund for Earthquake Scientific Research in Public Interest (Grant 201208004)National Natural Science Foundation of China (grant 41174040)Scientific Research Institutes’ Basic Research and Development Operations Special Fund of Institute of Geophysics,China Earthquake Administration (grant DQJB10A01)
文摘Western Yunnan is a region with intensive tectonic activity and serious earthquake risk. It is of significant importance to study three dimensional crustal structure of this region to understand the tectonic setting and disaster mechanism. Densification and digitalization of seismic networks in this region provides an opportunity to study the velocity structure with bulletin data. In this study, we collect P-wave data of 10 403 regional earthquakes recorded by 79 seismic stations from January 2008 to December 2010. In addition to first arrivals data （Pg with epieentral distance less than 200 km and Pn）, the Pg （or P） data with epicentral distance more than 200 km are also considered as later direct arrivals in the tomographic inversion. We also compare the quantity and the quality of the seismic data before 2010 and after 2010. The test results show that adding the follow-up Pg phase can effectively improve the inversion ability of crustal imaging, and quantity and the data quality are significantly improved since 2010. The tomographie results show that： （1） The Honghe fault zone, which is the major fault systems in this region, may cut through the entire crust, and the velocity contrasts between two sides at lower crust beneath the Honghe fault are estimated at higher than 10%, while the velocity difference below Nujiang fault zone extends only in the upper crust; （2） Most of the earthquakes in the region occurred at the interface of high-velocity media and low-velocity media, i.e., the areas with high velocity gradient, which has been validated in other areas.
基金National Natural Science Foundation of China (40074010) and Natural Science Foundation of Gansu Province(ZS981-A25-011).
文摘The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.
基金Foundation item: National Scientific and Technological Development Program (95-973-02-02) the Climb Program (95-S-05-01) of National Scientific and Technological Ministry of China and the State Natural Sciences Foundation of China (49874021).
文摘Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.
基金The project was financially supported by the National Natural Science Foundation of China
文摘Combined multi-body dynamics with structural dynamics, a new discrete element with flexible connector, which is applicable for 3-D beam structures, is developed in this paper. Both the generalized elastic coefficient matrix of the flexible connector and the mass matrix of discrete element may be off-diagonal in a general case. The zero-length rigid element is introduced to simulate the node at which multiple elements are jointed together. It may also be effective when the axes of adjacent elements are not in the same line. The examples for eigenvalue calculation show that the model is successful. It can be extended to the geometric nonlinear response analysis.
基金the "95" Key Project (Grant No. KZ2952-51-410) from the Chinese Academy of Sciences and a project from the National Natural Science Foundation of China.
文摘By processing the CSND Rayleigh wave data with the matched filter FTAN technique, Rayleigh wave dispersion for southeast China is obtained. The 4°×4°S wave dispersion of the pure path is calculated using random inversion scheme, and 3-D S wave velocity structure is set up. Incorporating the above-mentioned results with wide angle seismic sounding data, we studied structure framework and the extending of faults in this area, which demonstrates that the depth of Moho in South China varies from 30 to 40 km, shallower from west to east. The depth of Moho varies from 25 to 28 km for the offshore. The depth of the asthenosphere in upper mantle varies from 60 to 100 km. The depth difference of layers at the two sides of Tanlu fault is more than 10 km at the south part of the Yangtze River, and the fault extends downward more than 170 km. The fault exceeds the main land at Hainan Island and slips into the southern China Sea. Both Tanlu fault and the huge bend of gravity gradient anomaly are influenced by
基金Supported by the National Natural Science Foundation of China(21272167 and 21201127)a project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institution,Graduate Education Innovation Project in Jiangsu Province(CXZZ12_0808)+1 种基金Qinghai Science&Technology Department of China(2011-G-208 and 2011-Z-722)KLSLRC(KLSLRC-KF-13-HX-1)
文摘The title complex [Sr3（pda）2（Hpda）2（H2O）2]n·2nH2O（H2pda = pyridine-2,6-dicar- boxylic acid） has been prepared under solvothermal conditions. It has been characterized by X-ray single-crystal diffraction, IR and elemental analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 10.3795（8）, b = 9.2225（7）, c = 18.5726（14） , β = 104.377（2）o, V = 1722.2（2） 3, C28H22N4O20Sr3, Mr = 997.36, Z = 2, Dc = 1.923 g/cm3, μ = 4.722 mm-1, F（000） = 984, the final R = 0.0269 and wR = 0.0538. This complex possesses a 3-D structure which is constructed from 1-D chain motifs linked by carboxylate groups. The luminescent property of the title complex has been investigated.
文摘A simultaneous inversion of earthquake relocation and three-dimensional crustal structure of P-wave velocity in central-western China (21癗~36癗, 98癊~112癊) were performed in this paper. The crustal P-wave velocity model and earthquake relocation for this region are obtained using Pg and Sg phase readings of 9 988 earthquakes from 1992 to 1999 recorded at 193 seismic stations within central-western China by SPHYPIT90 and SPHREL3D90 programs. A lateral inhomogeneous structure of P-wave velocity in this region was obtained. Ob-vious contrast of P-wave velocities was revealed on both sides of active fault zones. Relocated epicenters of 6 459 events show clear lineation along active faults, which indicated a close correlation between seismicity and the active faults in this region. Focal depths of 82% relocated events ranged from 0 to 20 km, which is in good agreement with that from double-difference earthquake location algorithm.
