期刊文献+
共找到34,049篇文章
< 1 2 250 >
每页显示 20 50 100
Process-scheme-driven automatic construction of NC machining cell for aircraft structural parts 被引量:4
1
作者 Chen Shulin Zheng Guolei +2 位作者 Zhou Min Du Baorui Chu Hongzhen 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第5期1324-1335,共12页
In order to enhance the NC programming efficiency and quality of aircraft structural parts (ASPs), an intelligent NC programming pattern driven by process schemes is presented. In this pattern, the NC machining cell... In order to enhance the NC programming efficiency and quality of aircraft structural parts (ASPs), an intelligent NC programming pattern driven by process schemes is presented. In this pattern, the NC machining cell is the minimal organizational structure in the technological process, consisting of an operation machining volume cell, and the type and parameters of the machining operation. After the machining cell construction, the final NC program can be easily obtained in a CAD/CAM system by instantiating the machining operation for each machining cell. Accordingly, how to automatically establish the machining cells is a key issue in intelligent NC program- ming. On the basis of the NC machining craft of ASP, the paper aims to make an in-depth research on this issue. Firstly, some new terms about the residual volume and the machinable volume are defined, and then, the technological process is modeled with a process scheme. Secondly, the approach to building the machining cells is introduced, in which real-time complement machining is mainly considered to avoid interference and overcutting. Thirdly, the implementing algorithm is designed and applied to the Intelligent NC Programming System of ASP. Finally, the developed algorithm is validated through two case studies. 展开更多
关键词 Aircraft structural part (ASP) Automatic programming Machining cell Process planning Process scheme Residual volume
原文传递
An allowance allocation method based on dynamic approximation via online inspection data for deformation control of structural parts 被引量:1
2
作者 Xiaozhong HAO Yingguang LI +3 位作者 Chong HUANG Mengqiu LI Changqing LIU Kai TANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2020年第12期3495-3508,共14页
Deformation resulting from residual stress has been a significant issue in machining.As allowance allocation can directly impact the residual stress on part deformation,it is essential for deformation control.However,... Deformation resulting from residual stress has been a significant issue in machining.As allowance allocation can directly impact the residual stress on part deformation,it is essential for deformation control.However,it is difficult to adjust allowance allocation by traditional simulation methods based on residual stress,as the residual stress cannot be accurately measured or predicted,and many unexpected factors during machining process cannot be simulated accurately.Different from traditional methods,this paper proposes an allowance allocation method based on dynamic approximation via online inspection data for deformation control of structural parts.An Autoregressive Integrated Moving Average(ARIMA)model for dynamic allowance allocation is established so as to approach the minimum deformation,which is based on the in-process deformation inspection data during the alternative machining process of upside and downside.The effectiveness of the method is verified both by simulation cases and real machining experiments of aircraft structural parts,and the results show that part deformation can be significantly reduced. 展开更多
关键词 ARIMA model Deformation control Deformation inspection data Machining allowance allocation structural parts
原文传递
Development Trend of NC Machining Accuracy Control Technology for Aeronautical Structural Parts 被引量:1
3
作者 Qingchun Xiong Qinghua Zhou 《World Journal of Engineering and Technology》 2020年第3期266-279,共14页
High-performance five-axis computer numerical control machine tools are widely used in the processing of Aeronautical Structural parts. With the increase of service life, the precision of CNC machine tools equipped by... High-performance five-axis computer numerical control machine tools are widely used in the processing of Aeronautical Structural parts. With the increase of service life, the precision of CNC machine tools equipped by aeronautical manufacturing enterprises is declining day by day, while the new generation of aircraft structural parts <span style="font-family:Verdana;">are</span><span style="font-family:Verdana;"> developing towards integration, large-scale, complexity, thin-walled and lightweight. It is very easy to produce dimension overshoot and surface quality defects due to unstable processing technology. The machining accuracy of aircraft structural parts is also affected by complex factors such as cutting load, cutting stability, tool error, workpiece deformation, fixture deformation, etc. Because of the complexity of structure and characteristics of Aeronautical Structural parts, the consistency and stability of cutting process are poor. It is easy to cause machining accuracy problems due to tool wear, breakage and cutting chatter. Relevant scholars have carried out a lot of basic research on NC machining accuracy control and achieved fruitful results, but the research on NC machining accuracy control of Aeronautical structural parts is still less. This paper elaborates from three aspects: error modeling method of NC machine tools, error compensation method, prediction and control of machining accuracy, and combines the characteristics of Aeronautical Structural parts, the development trend and demand of NC machining accuracy control technology are put forward.</span> 展开更多
关键词 Aeronautical structural parts Machining Accuracy Error Compensation Machining Accuracy Control
在线阅读 下载PDF
Light-Weight Design Method for Force-Performance-Structure of Complex Structural Part Based Co-operative Optimization 被引量:5
4
作者 Ya-Li Ma Jian-Rong Tan +1 位作者 De-Lun Wang Zi-Zhe Liu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2018年第2期115-123,共9页
A light?weight design method of integrated structural topology and size co?optimization for the force?performance?structure of complex structural parts is presented in this paper. Firstly, the supporting function of a... A light?weight design method of integrated structural topology and size co?optimization for the force?performance?structure of complex structural parts is presented in this paper. Firstly, the supporting function of a complex structural part is built to map the force transmission, where the force exerted areas and constraints are considered as connecting structure and the structural configuration, to determine the part performance as well as the force routines. Then the connecting structure design model, aiming to optimize the static and dynamic performances on connection configuration, is developed, and the optimum design of the characteristic parameters is carried out by means of the collaborative optimization method, namely, the integrated structural topology optimization and size optimization. In this design model, the objective is to maximize the connecting stiffness. Based on the relationship between the force and the structural configuration of a part, the optimal force transmission routine that can meet the performance requirements is obtained using the structural topology optimization technology. Accordingly, the light?weight design of conceptual configuration for complex parts under multi?objective and multi?condition can be realized. Finally, based on the proposed collaborative optimization design method, the optimal performance and optimal structure of the complex parts with light weight are realized, and the reasonable structural unit configuration and size charac?teristic parameters are obtained. A bed structure of gantry?type machining center is designed by using the proposed light?weight structure design method in this paper, as an illustrative example. The bed after the design optimization is lighter 8% than original one, and the rail deformation is reduced by 5%. Moreover, the lightweight design of the bed is achieved with enhanced performance to show the effectiveness of the proposed method. 展开更多
关键词 Light?weight design part structure Topology optimization Size optimization FORCE PERFORMANCE
在线阅读 下载PDF
Global residual stress field inference method for die‑forging structural parts based on fusion of monitoring data and distribution prior
5
作者 Shuyuan Chen Yingguang Li +3 位作者 Changqing Liu Zhiwei Zhao Zhibin Chen Xiao Liu 《Visual Computing for Industry,Biomedicine,and Art》 2025年第1期60-73,共14页
Die-forging structural parts are widely used in the main load-bearing components of aircrafts because of their excellent mechanical properties and fatigue resistance.However,the forming and heat treatment processes of... Die-forging structural parts are widely used in the main load-bearing components of aircrafts because of their excellent mechanical properties and fatigue resistance.However,the forming and heat treatment processes of die-forging structural parts are complex,leading to high levels of internal stress and a complex distribution of residual stress fields(RSFs),which affect the deformation,fatigue life,and failure of structural parts throughout their lifecycles.Hence,the global RSF can provide the basis for process control.The existing RSF inference method based on deformation force data can utilize monitoring data to infer the global RSF of a regular part.However,owing to the irregular geometry of die-forging structural parts and the complexity of the RSF,it is challenging to solve ill-conditioned problems during the inference process,which makes it difficult to obtain the RSF accurately.This paper presents a global RSF inference method for the die-forging structural parts based on the fusion of monitoring data and distribution prior.Prior knowledge was derived from the RSF distribution trends obtained through finite element analysis.This enables the low-dimensional characterization of the RSF,reducing the number of parameters required to solve the equations.The effectiveness of this method was validated in both simulation and actual environments. 展开更多
关键词 Die-forging structural parts Global residual stress field inference Residual stress field partitioning Deformation force
在线阅读 下载PDF
Effects of partial structural damage in the dynamic characteristics of an existing RC building
6
作者 Fuat Aras 《Earthquake Engineering and Engineering Vibration》 2025年第3期781-793,共13页
Reinforced concrete buildings may experience partial damage after earthquakes or some human-induced actions.A decision about the future of those buildings requires detailed analyses,while determining the dynamic chara... Reinforced concrete buildings may experience partial damage after earthquakes or some human-induced actions.A decision about the future of those buildings requires detailed analyses,while determining the dynamic characteristics of a real building in its pre-and post-event situations can guide the analysis.Hence,this study was planned to monitor the dynamic response of an existing six-story,reinforced concrete building with regard to structural damage.The modal characteristics of the original building were initially determined by the use of operational modal analysis.Next,three steps of progressive structural damage were applied to the building.The first damage level peeled off the clear cover of a beam and three columns on a corner of the building’s ground floor.whereas the second and third levels completely razed the damaged columns.Operational modal analysis was repeated at each damage stage to extract the frequencies and detailed mode shapes.Moreover,numerical models based on the finite element method were constructed to confirm the obtained experimental findings.The well-agreed experimental and numerical findings revealed the damage sensitivity of the building’s dynamic response.The quantified amount of frequency change favored a retrofit of the partially damaged buildings rather than their replacement. 展开更多
关键词 operational modal analysis dynamic analysis structural damage column loss ambient vibration survey
在线阅读 下载PDF
Accelerated sintering and microstructural regulation of tungsten powder compact by novel modulation of particle configuration
7
作者 Peng Hu Yijie Gao +5 位作者 Hexiong Liu Yunfei Yang Qinqin Zhou Jung-Sik Kim Yaowu Hao Jinshu Wang 《Advanced Powder Materials》 2025年第5期10-19,共10页
Increasing the sintering rate of powder compact is a critical challenge of powder metallurgical materials,and adjusting component distribution in particles aggregate present significant effect on the microstructure of... Increasing the sintering rate of powder compact is a critical challenge of powder metallurgical materials,and adjusting component distribution in particles aggregate present significant effect on the microstructure of sintered product,especially for multi-phase compact with local heterogeneity.Here,a case study of W–Ni–Co powder compact was adopted to illustrate the novel strategy to enhance the sintering of multi-phase compact with desired microstructure by adjusting the particle configurations.The plasma synthesis route was developed for the first time to independently adjust the configurations of W–Ni–Co nanopowders with core-shell and homogeneous structures,which facilitates to ascertain the sintering response induced exclusively by particle configurations.Comparison on sintering response further indicates that core-shell powder presents greatly promoted sintering than homogeneous one,and full-dense and uniform compact with grain size of 1.37μm was obtained by solid sintering,which is several to dozens of times smaller than that obtained by conventional liquid sintering.Theoretical and experimental Investigation on elemental immigration visualized the distinct mass diffusion behavior of powder compacts,and clarified the mass transport path promoted densification mechanism determined by powder configurations.Importantly,full-coherent phase interface induced superior strength and plasticity in alloy sintered using core-shell powder,which highlights the importance of microstructural regulation on improving the mechanical property that superior than most of previously reported tungsten heavy alloys.In summary,this work paves a new way for fast sintering of multi-phase compacts,and provides intrinsic understandings on densification mechanism of powder compact. 展开更多
关键词 Thermal plasma Powder configuration SINTERING Structure evolution Multiphase compact
在线阅读 下载PDF
Mechanism of microstructural evolution in coke during the co-pyrolysis of coking coal with organic additives
8
作者 ZHAO Xinni TIAN Lu +3 位作者 YU Peng XU Xiuli DOU Jinxiao YU Jianglong 《燃料化学学报(中英文)》 北大核心 2026年第2期153-165,共13页
To deepen understanding of the evolution of coal char microstructural properties of coal char during the co-pyrolysis of coking coal with additives,this study incorporated two typical additives,coal tar pitch(CTP)and ... To deepen understanding of the evolution of coal char microstructural properties of coal char during the co-pyrolysis of coking coal with additives,this study incorporated two typical additives,coal tar pitch(CTP)and waste plastic(HDPE),into a blended coal sample and carried out pyrolysis experiments.The pyrolysis process and the microstructure of char were systematically characterized using various analytical techniques,including thermogravimetric analysis(TGA),X-ray diffraction(XRD)and Raman spectroscopy.Data correlation analysis was performed to reveal the mechanism of carbon structural ordering evolution within the critical temperature range(350−600℃)from colloidal layer formation to semi-coke conversion in coking coal,and to elucidate the regulatory effects of different additives on coal pyrolysis pathways.The results indicate that HDPE releases free radicals during high-temperature pyrolysis,accelerating the pyrolysis reaction and increase the yield of volatile components.Conversely,CTP facilitates pyrolysis at low temperatures through its light components,thereby delaying high-temperature reactions due to the colloidal layer’s effect.XRD results indicate that during the process of pyrolysis,there is a progressive decrease in the interlayer spacing of aromatic layers(d002),while the aromatic ring stacking height(L_(c))and lateral size(L_(a))undergo significant of carbon skeleton ordering.Further comparative reveals that CTP partially suppresses structural ordering at low temperatures,whereas HDPE promotes the condensation and alignment of aromatic clusters via a free radical mechanism.Raman spectroscopy reveals a two-stage reorganization mechanism in the microstructure of the coal char:the decrease in the I_(D)/I_(G)ratio between 350 and 550℃is primarily attributed to the cleavage of aliphatic side chains and cross-linking bonds,leading to a reduction in defective structures;whereas the increase in ID/IG between 550 and 600℃is closely associated with enhanced condensation reactions of aromatic structures.Correlation analysis further demonstrates progressive graphitization during pyrolysis,with a significant positive correlation(R^(2)>0.85)observed between d002 and the full width at half maximum of the G-band(FWHM-G). 展开更多
关键词 coking coal organic additives CO-PYROLYSIS colloidal layer carbon structure
在线阅读 下载PDF
Structural Influence on Radiation-induced Single-event Effects in SiC MOSFETs:Comparative Analysis of Planar and Trench Designs
9
作者 HU Libin FENG Shaohui +7 位作者 SUI Chenglong WANG Chengjie CHEN Miao LU Peng YANG Can SHU Lei LU Jiang LI Bo 《原子能科学技术》 北大核心 2026年第3期745-751,共7页
The single-event susceptibility of three silicon carbide(SiC)metal-oxide-semiconductor field-effect transistor(MOSFET)power devices structures(planar,trench and double trench)is researched by the technology computer-a... The single-event susceptibility of three silicon carbide(SiC)metal-oxide-semiconductor field-effect transistor(MOSFET)power devices structures(planar,trench and double trench)is researched by the technology computer-aided design(TCAD)simulation.Comparative analysis of the heavy-ion irradiation effects on three device structures reveals distinct susceptibility characteristics.The gate oxide region is identified as the most sensitive position in planar devices,while trench and doubletrench structures exhibit no localized sensitive regions.Furthermore,the single-event susceptibility demonstrates strong depth dependence across all three structures,with enhanced vulnerability observed at greater ion penetration depths. 展开更多
关键词 SiC MOSFET single-event susceptibility different structures TCAD simulation
在线阅读 下载PDF
Synthesis,structural characterization,electrocatalytic proton reduction,and fungicidal activity of thiazole‑containing di‑iron complexes
10
作者 JIANG Chengyu LIU Xufeng 《无机化学学报》 北大核心 2026年第2期355-364,共10页
This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the correspo... This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the corresponding ester[Fe_(2)(CO)_(6)(μ‑tedt)](2),where tedt=SCH_(2)CH(CH_(2)OOC(5‑C_(3)HNSCH_(3)))S.Further reactions of complex 2 with tri(ptolyl)phosphine(tp)or tris(4‑fluorophenyl)phosphine(fp)gave the phosphine‑substituted derivatives[Fe_(2)(CO)_(5)(tp)(μ‑tedt)](3)and[Fe_(2)(CO)_(5)(fp)(μ‑tedt)](4).The structures of the newly prepared complexes were elucidated by elemental analysis,NMR,IR,and X‑ray photoelectron spectroscopy.Moreover,single‑crystal X‑ray diffraction analysis confirmed their molecular structures,showing that they contain a di‑iron core ligated by a bridged dithiolate bearing a thiazole moiety and terminal carbonyls.The electrochemical and electrocatalytic proton reduction were probed by cyclic voltammetry,revealing that three complexes can catalyze the reduction of protons to H_(2) under the electrochemical conditions.For comparison,complex 4 possessed the best efficiency with a turnover frequency of 23.5 s^(-1)at 10 mmol·L^(-1)HOAc concentration.In addition,the fungicidal activity of these complexes was also investigated in this study.CCDC:2477511,2;2477512,3;2477513,4. 展开更多
关键词 THIAZOLE di‑iron complex crystal structure electrocatalytic proton reduction fungicidal activity
在线阅读 下载PDF
Structural engineering of nickel-rich cathode material for improved cycling performance of lithium-ion batteries
11
作者 Siyuan Zhang Pengxiang Ji +4 位作者 Sijie Guo Tingting Wu Muyao Qi Dong Su An-Min Cao 《Journal of Energy Chemistry》 2026年第3期52-59,共8页
Nickel-rich cathodes(NRCs)hold great promise for next-generation high-energy lithium-ion batteries(LIBs)due to high specific energy and low cost.However,the higher Ni content exacerbates the instability issues associa... Nickel-rich cathodes(NRCs)hold great promise for next-generation high-energy lithium-ion batteries(LIBs)due to high specific energy and low cost.However,the higher Ni content exacerbates the instability issues associated with structural degradation and side reactions during electrochemical cycling.Herein,we demonstrate the possibility of preparing NRCs,typically Li Ni_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM9055),with much-improved mechanical and chemical stability based on the surface coating of the hydroxide precursors.Specifically,a conformal nanoshell containing both Al^(3+)and W^(6+)was first deposited around the precursor particles,and the following high-temperature lithiation produced the targeted NCM9055 with favorable structural features,where Al3+existed as a bulk dopant to enhance the structural stability while the high-valent W^(6+)promoted the microstructural evolution into radially-architectured elongated primary particles.Such a structural engineering benefiting from the Al^(3+)/W^(6+)co-modification endowed the prepared NCM9055 cathode(NCM9055-Al W)with much-improved cycling stability,as revealed by a high-capacity retention of 98.0%after 100 cycles(tested at 0.5 C,4.3 V)as compared to only 79.0%for the pristine cathode without Al^(3+)/W^(6+).The NCM9055-15Al W cathode also showed a high-rate capability with extraordinary structural stability against mechanical failure.Our study highlighted the enormous potential of precursor multi-element treatment as an effective tool in structural refinement of NRCs to circumvent their stability challenge for their applications in high-energy LIBs. 展开更多
关键词 Ni-rich cathode Precursor treatment Multiple modification structural refinement structural stability MICROCRACKS
在线阅读 下载PDF
Realization of Polytype Heterostructures via Delicate Structural Transitions from a Doped Mott Insulator
12
作者 Yanyan Geng Manyu Wang +9 位作者 Shumin Meng Shuo Mi Chang Li Huiji Hu Jianfeng Guo Rui Xu Fei Pang Wei Ji Weichang Zhou Zhihai Cheng 《Chinese Physics Letters》 2026年第3期118-135,共18页
Transition-metal dichalcogenides hosting multiple competing structural and electronic phases are thus ideal platforms for constructing polytype heterostructures with emergent quantum properties.However,controlling pha... Transition-metal dichalcogenides hosting multiple competing structural and electronic phases are thus ideal platforms for constructing polytype heterostructures with emergent quantum properties.However,controlling phase transitions to form diverse heterostructures inside a single crystal remains challenging.In this study,we realize vertical/lateral polytype heterostructures in a hole-doped Mott insulator via thermal annealing-induced structural transitions.Raman spectroscopy,atomic force microscopy and scanning Kelvin probe force microscopy confirm the coexistence of T-H polytype heterostructures.Atomic-scale scanning tunneling microscopy/spectroscopy measurements reveal the transparent effect in 1H/1T vertical heterostructures,where positive bias voltage induces in a pronounced superposition of the√13×√13 CDW of the 1T-layer on the 1H-layer.By systematically comparing the 1T/1H and 1T/1T interfaces,we demonstrate that the metallic 1H-layer induces a Coulomb screening effect on the 1T-layer,suppressing the formation of CDW domain walls and forming more ordered electronic states.These results clarify the interfacial coupling between distinct quantum many-body phases and establish a controllable pathway for constructing two-dimensional polytype heterostructures with tunable electronic properties. 展开更多
关键词 Raman spectroscopy polytype heterostructures structural electronic phases spectroscopyatomic force microscopy thermal annealing structural transitions emergent quantum propertieshowevercontrolling phase transitions constructing polytype heterostructures
原文传递
Rao Zihe,Luminary in Structural Biology
13
作者 CHEN WENXIN 《China Today》 2026年第2期56-58,共3页
From cracking the code of viruses to mentoring the next generation of scientists,the former president of Nankai University has contributed a lot to turning microscopic discoveries into monumental shields for global he... From cracking the code of viruses to mentoring the next generation of scientists,the former president of Nankai University has contributed a lot to turning microscopic discoveries into monumental shields for global health.OVER the past 40 years,one man has distinguished himself through a deep commitment to researching protein structures of high pathogenic viruses,and published numerous significant works in top international scientific journals. 展开更多
关键词 viruses scientific mentoring protein structures structural biology global health cracking code viruses
在线阅读 下载PDF
Complex plastome structural variation caused by intermolecular and intramolecular recombination accounts for leaf variegation in Heptapleurum ellipticum
14
作者 Kainan Ma Shuaixi Zhou +1 位作者 Ying Liu Renchao Zhou 《Plant Diversity》 2026年第1期140-150,共11页
Plastome variation,including single spontaneous nucleotide substitutions and single insertions/deletions,is the major source of leaf variegation in plants.Additionally,one recent study has showed that a simple plastom... Plastome variation,including single spontaneous nucleotide substitutions and single insertions/deletions,is the major source of leaf variegation in plants.Additionally,one recent study has showed that a simple plastome structural variation,which is induced by one pair of small inverted repeats,can also result in leaf variegation.Here we show a complex plastome structural variation caused by intermolecular and intramolecular recombination across three pairs of small inverted repeats accounts for leaf variegation in a widely cultivated shrub Heptapleurum ellipticum(Araliaceae).This plastome structural variation contains two deletions and two duplications,resulting in dramatic expansion of IRs,substantial contraction of LSC and loss of 11 genes that essential for photosynthesis.Plastome heteroplasmy was detected in both green and albino sectors of variegated leaves.Relative to green sectors,albino sectors in the variegated leaves exhibit significantly reduced expression for the 11 genes lost in the mutated plastome as well as 26 other genes,but significantly increased expression for one gene related to translation apparatus.Optical and transmission electron microscopy observations showed that mesophyll cells of albino sectors possess plastids lacking grana lamellae,which likely carry the mutated plastome and contribute to albinism.In both sectors,the first layer of spongy mesophyll cells beneath the lower epidermis contains normal chloroplasts,suggesting periclinal division of the lower epidermis during development.Our study demonstrates that multiple small repeats can collectively mediate intra-and inter-molecular recombination in plastome and offers a new mechanism accounting for leaf variegation in plants. 展开更多
关键词 HETEROPLASMY Recombination PLASTOME structural variation VARIEGATION Small repeats
在线阅读 下载PDF
Structural disorder-driven synthesis of C_(2+)hydrocarbons via direct hydrogenation of amorphous carbon with continuous random atomic networks
15
作者 Shaojie Wang Mingtao Li +10 位作者 Zhongyan Wu Saichao Cao Penghui Li Xiang Zhang Zhiwei Shen Hongkai Li Ke Yang Li Zhang Guoying Gao Lin Wang Yongjun Tian 《Matter and Radiation at Extremes》 2026年第1期93-102,共10页
Recent advances in geoscience have underscored the critical role of abiogenic processes in petroleum formation,especially the formation and polymerization of methane.However,whether a direct carbon-H_(2) reaction can ... Recent advances in geoscience have underscored the critical role of abiogenic processes in petroleum formation,especially the formation and polymerization of methane.However,whether a direct carbon-H_(2) reaction can produce C_(2+)hydrocarbons(e.g.,ethane and propane)beyond methane remains an open question.Here,we demonstrate the direct synthesis of ethane and propane via reactions between amorphous carbon and H_(2) under upper mantle conditions(2-10 GPa and 800-1200℃).A systematic investigation reveals that increasing structural disorder in carbon precursors,from graphite to glassy carbon-Ⅱ and carbon black,enhances the production of C_(2)-C_(3) hydrocarbons.Through integrated X-ray diffraction and reverse Monte Carlo simulations,we establish that the continuous random atomic network structures in amorphous carbon enable one-step synthesis of heavy hydrocarbons with H_(2).These models establish a direct link between atomic-scale carbon structures and the one-step synthesis of C_(2+) hydrocarbons under H_(2)-rich,high-pressure,and high-temperature conditions—potentially revealing an efficient mechanism for the abiotic production of C_(2+) hydrocarbons in the upper mantle. 展开更多
关键词 systematic investigation abiogenic processes formation polymerization HYDROGENATION amorphous carbon ETHANE structural disorder PROPANE
在线阅读 下载PDF
Structural chromosome variations from Jinmai 47 and Jinmai 84 affected agronomic traits and drought tolerance of wheat
16
作者 Shuwei Zhang Jiajia Zhao +9 位作者 Haiyan Zhang Duoduo Fu Ling Qiao Bangbang Wu Xiaohua Li Yuqiong Hao Xingwei Zheng Zhen Liang Zhijian Chang Jun Zheng 《Journal of Integrative Agriculture》 2026年第3期864-878,共15页
Structural variation is an important source of genetic variation in wheat and have been important in the evolution of the wheat's genome.Few studies have examined the relationship between structural variations and... Structural variation is an important source of genetic variation in wheat and have been important in the evolution of the wheat's genome.Few studies have examined the relationship between structural variations and agronomy and drought tolerance.The present study identified structural chromosome variations(SCVs)in a doubled haploid(DH)population and backcross introgression lines(BC5F3)derived from Jinmai 47 and Jinmai 84 using fluorescence in situ hybridization(FISH).There are one simple translocation,10 present/absent variations(PAVs),and one copy number variation(CNV)between Jinmai 47 and Jinmai 84,which distributed in 10 chromosomes.Eight SCVs were associated with 15 agronomic traits.A PAV recombination occurred on chromosome 2A,which was associated with grain number per spike(GNS).The 1BL/1RS translocation and PAV.2D were associated with significant reductions in plant height,deriving from the effects on LI2-LI4,LI2-LI4 and UI,respectively respectively.PAV.2D was also contributed to an increase of 3.13%for GNS,1BL/1RS significantly increased spikelet number,grain length(GL),and grain thickness(GT).The effect of PAV.4A.1 on GL,PAV.6A on spike length(SL)and thousand-grain weight(TGW),PAV.6B on SL,GT and TGW were identified and verified.PAVs on chromosomes 2A,6A,1D,2D,and a CNV on chromosome 4B were associated with the drought tolerance coefficients.Additive and interaction effects among SCVs were observed.Many previously cloned key genes and yield-related QTL were found in polymorphic regions of PAV.2B,PAV.2D,and CNV.4B.Altogether,this study confirmed the genetic effect of SCVs on agronomy and drought tolerance,and identification of these SCVs will facilitate genetic improvement of wheat through marker-assisted selection. 展开更多
关键词 WHEAT structural chromosome variation AGRONOMY drought tolerance effect
在线阅读 下载PDF
Dual-Mode Sensor with Saturated Mechanochromic Structural Color Enhanced by Black Conductive Hydrogel for Interactive Rehabilitation Monitoring
17
作者 Zhiyuan Sun Binhong Yu +10 位作者 Chao Dong Chengjun Yu Lianghe Sheng Zhe Cui Yaming Liu Zhenni Lu Bingda Chen Daixi Xie Zhandong Huang Songshan Zeng Qingdong Ou 《Nano-Micro Letters》 2026年第4期153-171,共19页
Flexible and wearable sensors offer immense potential for rehabilitation medicine,but most rely solely on electrical signals,lacking real-time visual feedback and limiting trainee's interactivity.Inspired by the s... Flexible and wearable sensors offer immense potential for rehabilitation medicine,but most rely solely on electrical signals,lacking real-time visual feedback and limiting trainee's interactivity.Inspired by the structural coloration of Cyanocitta stelleri feathers,we developed a dual-mode sensor by utilizing black conductive polymer hydrogel(CPH)-enhanced structural color strategy.This sensor integrates a hydroxypropyl cellulose(HPC)-based structural color interface with a designed CPH sensing component.Highly visible light-absorbing CPH(absorption rate>88%)serves as the critical substrate for enhancing structural color performance.By absorbing incoherent scattered light and suppressing background interference,it significantly enhances the saturation of structural color,thereby achieving a high contrast index of 4.92.Unlike the faint and hardly visible structural colors on non-black substrates,the HPC on CPH displays vivid,highly perceptible colors and desirable mechanochromic behavior.Moreover,the CPH acts as a flexible sensing element,fortified by hydrogen and coordination bond networks,and exhibits exceptional electromechanical properties,including 867.1 kPa tensile strength,strain sensitivity(gauge factor of 4.24),and outstanding durability(over 4400 cycles).Compared to traditional single-mode sensors,the integrated sensor provides real-time visual and digital dual feedback,enhancing the accuracy and interactivity of rehabilitation assessments.This technology holds promise for advancing next-generation rehabilitation medicine. 展开更多
关键词 Conductive hydrogel structural color Hydroxypropyl cellulose Dual-mode sensor Rehabilitation monitoring
在线阅读 下载PDF
Deciphering China’s Growth Target:Structural strength, innovation momentum and policy capacity underpin the stability of the world’s second-largest economy
18
作者 XU HAO 《ChinAfrica》 2026年第4期44-46,共3页
China has set its economic growth target for 2026 in the range of 4.5-5 percent.After three consecutive years of aiming for growth of around 5 percent,the slightly adjusted range reflects a prudent assessment of a com... China has set its economic growth target for 2026 in the range of 4.5-5 percent.After three consecutive years of aiming for growth of around 5 percent,the slightly adjusted range reflects a prudent assessment of a complex global environment while still signalling a commitment to stable development. 展开更多
关键词 economic growth structural strength policy capacity global environment innovation momentum
原文传递
Definition of critical skin defect and concepts of structural and functional repairs:Proposal and verification in a rat model
19
作者 Cong Sun Weihong Guo +4 位作者 Fang Liang Rabia Javed Weijian Hou Xingdong Zhang Qiang Ao 《Animal Models and Experimental Medicine》 2026年第1期168-182,共15页
Background:Rats are often used to prepare skin defect models.However,the skin defect sizes of the models prepared by researchers are different,and the lack of consensus on the critical-size defect makes it difficult t... Background:Rats are often used to prepare skin defect models.However,the skin defect sizes of the models prepared by researchers are different,and the lack of consensus on the critical-size defect makes it difficult to compare their research results.Methods:The time for wound closure was evaluated and recorded through gross observation.The regression equation between the healing time and the diameter of skin defect was established,which can be used to predict the healing time for a certain skin defect size in rats.Histochemical and immunohistochemical staining was used to observe the regeneration and reconstruction of skin appendages,and the functional skin repair was quantitatively scored.Results:The critical-size defect of rats was determined based on the maximum capacity of structural skin repair,and the functional skin repair was quantitatively scored based on the regeneration and reconstruction of skin appendages.The allowable range of critical-size skin defect of SD rats lies between 45 and 50 mm in diameter.The concept of structural repair and the category of functional repair of injured skin are put forward.The regression equation between the structural skin healing time and defect diameters is established.Conclusion:The allowable range of skin critical-size defect of SD rats lies between 45 and 50 mm in diameter.The regression equation between the structural skin healing time and defect diameters can be used to predict the healing time for a certain skin defect size in rats. 展开更多
关键词 critical defect functional repair quantitative evaluation skin defect structural repair
暂未订购
Structural optimization and fabrication of energy storage materials based on additive manufacturing technology
20
作者 Xiaowen Ma Xu Wang +3 位作者 Haoran Shi Yongchang Liu Baicheng Zhang Xuanhui Qu 《International Journal of Minerals,Metallurgy and Materials》 2026年第2期467-478,共12页
Achieving high energy and power densities is currently a core challenge in the fabrication of energy storage materials.Although numerous high-capacity materials have been developed,conventional planar electrodes canno... Achieving high energy and power densities is currently a core challenge in the fabrication of energy storage materials.Although numerous high-capacity materials have been developed,conventional planar electrodes cannot achieve high active material loading and efficient ion/electron transport simultaneously.By contrast,three-dimensional(3D)structures have attracted increasing interest because of their capacity to enhance active material utilization,shorten ion and electron transport pathways,reduce interfacial impedance,and provide spatial accommodation for volume expansion.Additive manufacturing(AM)technology effectively fabricates energy-storage materials with 3D structures by accurately constructing complex 3D structures via layer-by-layer deposition.Recent studies have employed AM to construct ordered 3D electrodes that can optimize ion/electron transport,regulate electric field distribution,or improve the electrode-electrolyte interface,thereby contributing to enhanced kinetic performance and cycling stability.This review systematically summarizes the applications of several AM technologies in the fabrication of energy storage materials and analyzes their respective advantages and limitations.Subsequently,the advantages of AM technology in the fabrication of energy storage materials and several major optimization strategies are comprehensively discussed.Finally,the major challenges and potential applications of AM technology in energy storage material optimization are discussed. 展开更多
关键词 additive manufacturing porous structures all-solid-state batteries structured electrodes solid electrolyte energy storage materials
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部