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Impact resistance performance and optimization of the sand-EPE composite cushion in rock sheds 被引量:2
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作者 YU Bingxin ZHOU Xiaojun +2 位作者 TANG Jianhui ZHANG Yujin ZHANG Yuefeng 《Journal of Mountain Science》 SCIE CSCD 2024年第2期676-689,共14页
Rock sheds are widely used to prevent rockfall disasters along roads in mountainous areas.To improve the capacity of rock sheds for resisting rockfall impact,a sand and expandable polyethylene(EPE)composite cushion wa... Rock sheds are widely used to prevent rockfall disasters along roads in mountainous areas.To improve the capacity of rock sheds for resisting rockfall impact,a sand and expandable polyethylene(EPE)composite cushion was proposed.A series of model experiments of rockfall impact on rock sheds were conducted,and the buried depth of the EPE foam board in the sand layer was considered.The impact load and dynamic response of the rock shed were investigated.The results show that the maximum impact load and dynamic response of the rock shed roof are all significantly less than those of the sand cushion.Moreover,as the distance between the EPE foam board and rock shed roof decreases,the maximum rockfall impact force and impact pressure gradually decrease,and the maximum displacement,acceleration and strain of the rock shed first decrease and then change little.In addition,the vibration acceleration and vertical displacement of the rock shed roof decrease from the centre to the edge and decrease faster along the longitudinal direction than that along the transverse direction.In conclusion,the buffering effect of the sand-EPE composite cushion is better than that of the pure sand cushion,and the EPE foam board at a depth of 1/3 the thickness of the sand layer is appropriate. 展开更多
关键词 ROCKFALL Rock shed Impact composite cushion Buffering effect Dynamic response
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Ti_(3)C_(2)T_(x) MXene/carbon composites for advanced supercapacitors:Synthesis,progress,and perspectives 被引量:1
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作者 Yanqing Cai Xinggang Chen +4 位作者 Ying Xu Yalin Zhang Huijun Liu Hongjuan Zhang Jing Tang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第2期113-142,共30页
MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivi... MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivity,good hydrophilicity,and tunable terminations.Among various types of MXenes,Ti_(3)C_(2)T_(x) is the most widely studied for use in capacitive energy storage applications,especially in supercapacitors(SCs).However,the stacking and oxidation of MXene sheets inevitably lead to a significant loss of electrochemically active sites.To overcome such challenges,carbon materials are frequently incorporated into MXenes to enhance their electrochemical properties.This review introduces the common strategies used for synthesizing Ti_(3)C_(2)T_(x),followed by a comprehensive overview of recent developments in Ti_(3)C_(2)T_(x)/carbon composites as electrode materials for SCs.Ti_(3)C_(2)T_(x)/carbon composites are categorized based on the dimensions of carbons,including 0D carbon dots,1D carbon nanotubes and fibers,2D graphene,and 3D carbon materials(activated carbon,polymer-derived carbon,etc.).Finally,this review also provides a perspective on developing novel MXenes/carbon composites as electrodes for application in SCs. 展开更多
关键词 electrochemical performance MXene/carbon composites SUPERCAPACITORS
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Laser‑Induced and MOF‑Derived Metal Oxide/Carbon Composite for Synergistically Improved Ethanol Sensing at Room temperature 被引量:1
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作者 Hyeongtae Lim Hyeokjin Kwon +2 位作者 Hongki Kang Jae Eun Jang Hyuk‑Jun Kwon 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第6期210-220,共11页
Advancements in sensor technology have significantly enhanced atmospheric monitoring.Notably,metal oxide and carbon(MO_(x)/C)hybrids have gained attention for their exceptional sensitivity and room-temperature sensing... Advancements in sensor technology have significantly enhanced atmospheric monitoring.Notably,metal oxide and carbon(MO_(x)/C)hybrids have gained attention for their exceptional sensitivity and room-temperature sensing performance.However,previous methods of synthesizing MO_(x)/C composites suffer from problems,including inhomogeneity,aggregation,and challenges in micropatterning.Herein,we introduce a refined method that employs a metal–organic framework(MOF)as a precursor combined with direct laser writing.The inherent structure of MOFs ensures a uniform distribution of metal ions and organic linkers,yielding homogeneous MO_(x)/C structures.The laser processing facilitates precise micropatterning(<2μm,comparable to typical photolithography)of the MO_(x)/C crystals.The optimized MOF-derived MO_(x)/C sensor rapidly detected ethanol gas even at room temperature(105 and 18 s for response and recovery,respectively),with a broad range of sensing performance from 170 to 3,400 ppm and a high response value of up to 3,500%.Additionally,this sensor exhibited enhanced stability and thermal resilience compared to previous MOF-based counterparts.This research opens up promising avenues for practical applications in MOF-derived sensing devices. 展开更多
关键词 Metal-organic frameworks Metal oxide Carbon composite LASER Gas sensor
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Mechanical behaviors of backfill-rock composites: Physical shear test and back-analysis 被引量:1
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作者 Jie Xin Quan Jiang +5 位作者 Fengqiang Gong Lang Liu Chang Liu Qiang Liu Yao Yang Pengfei Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期807-827,共21页
The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface subsidence.For exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backf... The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface subsidence.For exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backfill-rock composites under three constant normal loads,compared with the unfilled rock.To investigate the macro-and meso-failure characteristics of the samples in the shear tests,the cracking behavior of samples was recorded by a high-speed camera and acoustic emission monitoring.In parallel with the experimental test,the numerical models of backfill-rock composites and unfilled rock were established using the discrete element method to analyze the continuous-discontinuous shearing process.Based on the damage mechanics and statistics,a novel shear constitutive model was proposed to describe mechanical behavior.The results show that backfill-rock composites had a special bimodal phenomenon of shearing load-deformation curve,i.e.the first shearing peak corresponded to rock break and the second shearing peak induced by the broken of aeolian sand-cement/fly ash paste backfill.Moreover,the shearing characteristic curves of the backfill-rock composites could be roughly divided into four stages,i.e.the shear failure of the specimens experienced:stage I:stress concentration;stage II:crack propagation;stage III:crack coalescence;stage IV:shearing friction.The numerical simulation shows that the existence of aeolian sand-cement/fly ash paste backfill inevitably altered the coalescence type and failure mode of the specimens and had a strengthening effect on the shear strength of backfillrock composites.Based on damage mechanics and statistics,a shear constitutive model was proposed to describe the shear fracture characteristics of specimens,especially the bimodal phenomenon.Finally,the micro-and meso-mechanisms of shear failure were discussed by combining the micro-test and numerical results.The research can advance the better understanding of the shear behavior of backfill-rock composites and contribute to the safety of mining engineering. 展开更多
关键词 Physical simulation Backfill-rock composites Shear failure CRACKING Shear constitutive model
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Ultraviolet‑Irradiated All‑Organic Nanocomposites with Polymer Dots for High‑Temperature Capacitive Energy Storage 被引量:1
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作者 Jiale Ding Yao Zhou +5 位作者 Wenhan Xu Fan Yang Danying Zhao Yunhe Zhang Zhenhua Jiang Qing Wang 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期398-406,共9页
Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have bee... Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have been extensively utilized to improved high-temperature capacitive performance of dielectric polymers,the presence of thermodynamically incompatible organic and inorganic components may lead to concern about the long-term stability and also complicate film processing.Herein,zero-dimensional polymer dots with high electron affinity are introduced into photoactive allyl-containing poly(aryl ether sulfone)to form the all-organic polymer composites for hightemperature capacitive energy storage.Upon ultraviolet irradiation,the crosslinked polymer composites with polymer dots are efficient in suppressing electrical conduction at high electric fields and elevated temperatures,which significantly reduces the high-field energy loss of the composites at 200℃.Accordingly,the ultraviolet-irradiated composite film exhibits a discharged energy density of 4.2 J cm^(−3)at 200℃.Along with outstanding cyclic stability of capacitive performance at 200℃,this work provides a promising class of dielectric materials for robust high-performance all-organic dielectric nanocomposites. 展开更多
关键词 High-temperature energy storage Polymer dots Ultraviolet irradiation All-organic composite dielectrics
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Snap-through behaviors and nonlinear vibrations of a bistable composite laminated cantilever shell:an experimental and numerical study 被引量:2
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作者 Lele REN Wei ZHANG +1 位作者 Ting DONG Yufei ZHANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第5期779-794,共16页
The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.... The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.An improved experimental specimen is designed in order to satisfy the cantilever support boundary condition,which is composed of an asymmetric region and a symmetric region.The symmetric region of the experimental specimen is entirely clamped,which is rigidly connected to an electromagnetic shaker,while the asymmetric region remains free of constraint.Different motion paths are realized for the bistable cantilever shell by changing the input signal levels of the electromagnetic shaker,and the displacement responses of the shell are collected by the laser displacement sensors.The numerical simulation is conducted based on the established theoretical model of the bistable composite laminated cantilever shell,and an off-axis three-dimensional dynamic snap-through domain is obtained.The numerical solutions are in good agreement with the experimental results.The nonlinear stiffness characteristics,dynamic snap-through domain,and chaos and bifurcation behaviors of the shell are quantitatively analyzed.Due to the asymmetry of the boundary condition and the shell,the upper stable-state of the shell exhibits an obvious soft spring stiffness characteristic,and the lower stable-state shows a linear stiffness characteristic of the shell. 展开更多
关键词 bistable composite laminated cantilever shell snap-through behavior nonlinear vibration nonlinear stiffness characteristic chaos and bifurcation
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Transient response of doubly-curved bio-inspired composite shells resting on viscoelastic foundation subject to blast load using improved first-order shear theory and isogeometric approach 被引量:1
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作者 Thuy Tran Thi Thu Tu Nguyen Anh +1 位作者 Hue Nguyen Thi Hong Nguyen Thi 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第8期171-193,共23页
Investigating natural-inspired applications is a perennially appealing subject for scientists. The current increase in the speed of natural-origin structure growth may be linked to their superior mechanical properties... Investigating natural-inspired applications is a perennially appealing subject for scientists. The current increase in the speed of natural-origin structure growth may be linked to their superior mechanical properties and environmental resilience. Biological composite structures with helicoidal schemes and designs have remarkable capacities to absorb impact energy and withstand damage. However, there is a dearth of extensive study on the influence of fiber redirection and reorientation inside the matrix of a helicoid structure on its mechanical performance and reactivity. The present study aimed to explore the static and transient responses of a bio-inspired helicoid laminated composite(B-iHLC) shell under the influence of an explosive load using an isomorphic method. The structural integrity of the shell is maintained by a viscoelastic basis known as the Pasternak foundation, which encompasses two coefficients of stiffness and one coefficient of damping. The equilibrium equations governing shell dynamics are obtained by using Hamilton's principle and including the modified first-order shear theory,therefore obviating the need to employ a shear correction factor. The paper's model and approach are validated by doing numerical comparisons with respected publications. The findings of this study may be used in the construction of military and civilian infrastructure in situations when the structure is subjected to severe stresses that might potentially result in catastrophic collapse. The findings of this paper serve as the foundation for several other issues, including geometric optimization and the dynamic response of similar mechanical structures. 展开更多
关键词 Blast load Modified first-order shear theory Biological composite structures
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Self‑Assembly of Binderless MXene Aerogel for Multiple‑Scenario and Responsive Phase Change Composites with Ultrahigh Thermal Energy Storage Density and Exceptional Electromagnetic Interference Shielding 被引量:1
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作者 Chuanbiao Zhu Yurong Hao +8 位作者 Hao Wu Mengni Chen Bingqing Quan Shuang Liu Xinpeng Hu Shilong Liu Qinghong Ji Xiang Lu Jinping Qu 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期367-382,共16页
The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here... The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs. 展开更多
关键词 Self-assembly Multiple-scenario Phase change composites Thermal energy storage Electromagnetic interference shielding
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Electrostatic Interaction-directed Construction of Hierarchical Nanostructured Carbon Composite with Dual Electrical Conductive Networks for Zinc-ion Hybrid Capacitors with Ultrastability 被引量:1
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作者 Changyu Leng Zongbin Zhao +5 位作者 Xuzhen Wang Yuliya V.Fedoseeva Lyubov G.Bulusheva Alexander V.Okotrub Jian Xiao Jieshan Qiu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第1期184-192,共9页
Metal-organic framework(MOF)-derived carbon composites have been considered as the promising materials for energy storage.However,the construction of MOF-based composites with highly controllable mode via the liquid-l... Metal-organic framework(MOF)-derived carbon composites have been considered as the promising materials for energy storage.However,the construction of MOF-based composites with highly controllable mode via the liquid-liquid synthesis method has a great challenge because of the simultaneous heterogeneous nucleation on substrates and the self-nucleation of individual MOF nanocrystals in the liquid phase.Herein,we report a bidirectional electrostatic generated self-assembly strategy to achieve the precisely controlled coatings of single-layer nanoscale MOFs on a range of substrates,including carbon nanotubes(CNTs),graphene oxide(GO),MXene,layered double hydroxides(LDHs),MOFs,and SiO_(2).The obtained MOF-based nanostructured carbon composite exhibits the hierarchical porosity(V_(meso)/V_(micro)∶2.4),ultrahigh N content of 12.4 at.%and"dual electrical conductive networks."The assembled aqueous zinc-ion hybrid capacitor(ZIC)with the prepared nanocarbon composite as a cathode shows a high specific capacitance of 236 F g^(-1)at 0.5 A g^(-1),great rate performance of 98 F g^(-1)at 100 A g^(-1),and especially,an ultralong cycling stability up to 230000 cycles with the capacitance retention of 90.1%.This work develops a repeatable and general method for the controlled construction of MOF coatings on various functional substrates and further fabricates carbon composites for ZICs with ultrastability. 展开更多
关键词 carbon composite electrostatic interaction metal-organic framework coating SELF-ASSEMBLY zinc-ion hybrid capacitor
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Highly Aligned Graphene Aerogels for Multifunctional Composites 被引量:1
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作者 Ying Wu Chao An +4 位作者 Yaru Guo Yangyang Zong Naisheng Jiang Qingbin Zheng Zhong‑Zhen Yu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第6期276-342,共67页
Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,an... Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,and thermal properties.To maximize the utilization of graphene’s in-plane properties,pre-constructed and aligned structures,such as oriented aerogels,films,and fibers,have been designed.The unique combination of aligned structure,high surface area,excellent electrical conductivity,mechanical stability,thermal conductivity,and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions,enabling advancements in diverse fields.This review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their composites.It highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and quantitatively.The oriented scaffolds endow graphene aerogels and their composites with anisotropic properties,showing enhanced electrical,mechanical,and thermal properties along the alignment at the sacrifice of the perpendicular direction.This review showcases remarkable properties and applications of aligned graphene aerogels and their composites,such as their suitability for electronics,environmental applications,thermal management,and energy storage.Challenges and potential opportunities are proposed to offer new insights into prospects of this material. 展开更多
关键词 Highly aligned graphene aerogels Quantitative characterization of alignment Multifunctional composites Anisotropic properties Multifunctional applications
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Development and application of novel high‐efficiency composite ultrafine cement grouts for roadway in fractured surrounding rocks 被引量:1
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作者 Maolin Tian Shaojie Chen +1 位作者 Lijun Han Hongtian Xiao 《Deep Underground Science and Engineering》 2024年第1期53-69,共17页
The fractured surrounding rocks of roadways pose major challenges to safe mining.Grouting has often been used to reinforce the surrounding rocks to mitigate the safety risks associated with fractured rocks.The aim of ... The fractured surrounding rocks of roadways pose major challenges to safe mining.Grouting has often been used to reinforce the surrounding rocks to mitigate the safety risks associated with fractured rocks.The aim of this study is to develop highly efficient composite ultrafine cement(CUC)grouts to reinforce the roadway in fractured surrounding rocks.The materials used are ultrafine cement(UC),ultrafine fly ash(UF),ultrafine slag(US),and additives(superplasticizer[SUP],aluminate ultrafine expansion agent[AUA],gypsum,and retarder).The fluidity,bleeding,shrinkage,setting time,chemical composition,microstructure,degree of hydration,and mechanical property of grouting materials were evaluated in this study.Also,a suitable and effective CUC grout mixture was used to reinforce the roadway in the fractured surrounding rock.The results have shown that the addition of UF and US reduces the plastic viscosity of CUC,and the best fluidity can be obtained by adding 40%UF and 10%US.Since UC and UF particles are small,the pozzolanic effect of UF promotes the hydration reaction,which is conductive to the stability of CUC grouts.In addition,fine particles of UC,UF,and US can effectively fill the pores,while the volumetric expansion of AUA and gypsum decreases the pores and thus affects the microstructure of the solidified grout.The compressive test results have shown that the addition of specific amounts of UF and US can ameliorate the mechanical properties of CUC grouts.Finally,the CUC22‐8 grout was used to reinforce the No.20322 belt roadway.The results of numerical simulation and field monitoring have indicated that grouting can efficaciously reinforce the surrounding rock of the roadway.In this research,high‐performance CUC grouts were developed for surrounding rock reinforcement of underground engineering by utilizing UC and some additives. 展开更多
关键词 broken surrounding rock composite ultrafine cement(CUC)grouts grouting material grouting performance grouting reinforcement
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Effects of Sinusoidal Vibration of Crystallization Roller on Composite Microstructure of Ti/Al Laminated Composites by Twin-Roll Casting
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作者 李励 杜凤山 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期196-205,共10页
A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/... A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/Al laminated composites,and the effect of sinusoidal vibration of crystallization roller on composite microstructure was investigated in detail.The results show that the metallurgical bonding of titanium and aluminum is realized by mesh interweaving and mosaic meshing,instead of transition bonding by forming metal compound layer.The meshing depth between titanium and aluminum layers (6.6μm) of cast-rolling materials with strong vibration of crystallization roller (amplitude 0.87 mm,vibration frequency 25 Hz) is doubled compared with that of traditional cast-rolling materials (3.1μm),and the composite interfacial strength(27.0 N/mm) is twice as high as that of traditional cast-rolling materials (14.9 N/mm).This is because with the action of high-speed superposition of strong tension along the rolling direction,strong pressure along the width direction and rolling force,the composite linearity evolves from "straight line" with traditional casting-rolling to "curved line",and the depth and number of cracks in the interface increases greatly compared with those with traditional cast-rolling,which leads to the deep expansion of the meshing area between interfacial layers and promotes the stable enhancement of composite quality. 展开更多
关键词 laminated composites sinusoidal vibration composite microstructure
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Preparation and Performance of Organically Modified Montmorillonite Composite Separation Membrane
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作者 LIU Peng BI Yuanyuan +7 位作者 CHEN Shaowei WAN Ye YU Yunwu FANG Yanfeng GU Yaxin LI Feihong TANG Ning LI Xiangyu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第5期1100-1107,共8页
A new composite separation membrane was developed by using organically modified montmorillonite(OMMT)as an additive.The effects of OMMT on the modification and properties of PVDF composite membranes were investigated.... A new composite separation membrane was developed by using organically modified montmorillonite(OMMT)as an additive.The effects of OMMT on the modification and properties of PVDF composite membranes were investigated.It is found that different kinds and amounts of OMMT into the casting solution can obviously change the pure water flux,separation performance and hydrophilicity of composite membrane in varying degrees.When the TA/PDA-MMT was 0.5 wt%,the pure water flux of the membrane reached the maximum,which was 584.7 L/(m^(2)·h),about 6 times that of the original membrane.The OMMT/PVDF composite membrane had good hydrophilicity and stability in the treatment of oily wastewater.The development of novel OMMT/PVDF composite membrane will provide a new idea for solving the problem of oily wastewater treatment. 展开更多
关键词 MEMBRANE MONTMORILLONITE composite WASTEWATER
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How do the non-linear I-V curves of ZnO-based adaptive composites behave with electrodes placed on the opposite sides with a series of horizontal distances?
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作者 Ya Sun Zhikang Yuan +3 位作者 Zhiwen Huang Jun Hu Jinliang He Qi Li 《High Voltage》 SCIE EI CSCD 2024年第5期981-988,共8页
Recently,ZnO-based composites have been widely applied in the field of electric power.To meet the diverse application requirements,it is necessary to figure out the I-V characteristics of ZnO composites whose high-vol... Recently,ZnO-based composites have been widely applied in the field of electric power.To meet the diverse application requirements,it is necessary to figure out the I-V characteristics of ZnO composites whose high-voltage and ground-voltage electrodes are arranged on the opposite sides with a certain horizontal distance.30 vol%,40 vol%and 50 vol%ZnO-based silicone rubber composites were prepared.The horizontal distance between their electrodes was set as 50,100,500μm,1 and 2 mm,respectively.Results showed that with the increase of ZnO fillers volume fraction under a fixed horizontal distance of 100μm,from 30 vol%to 50 vol%,the I-V curves shifted left,the leakage current increased and the switching voltage decreased.When the horizontal distance between electrodes increased from 50μm to 1 mm under a fixed doping concentration of 40%,the I-V curves shifted to the right,the leakage current dropped and the switching voltage rose.The mathematical and physical models were established to explain the results.This work provides a referential significance for the practical application of ZnO composites,such as 5G folding mobile phones and power electronic modules. 展开更多
关键词 compositeS RUBBER linear
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Enhanced surface flashover performance of oriented hexagonal boron nitride composites via anisotropic charge transportation
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作者 Yingfan Zhang Haohuan Wang +1 位作者 Zhengyong Huang Jian Li 《High Voltage》 SCIE EI CSCD 2024年第5期1011-1020,共10页
Surface flashover is a crucial issue for the miniaturisation of electronic facilities in military,industrial,and aerospace engineering.The oriented hexagonal boron nitride(hBN)composites,due to excellent thermal and e... Surface flashover is a crucial issue for the miniaturisation of electronic facilities in military,industrial,and aerospace engineering.The oriented hexagonal boron nitride(hBN)composites,due to excellent thermal and electrical insulating properties,show a potential application in high-voltage power equipment,while the surface flashover performance of hBN composites dependent on oriented hBN texture is rarely reported.The effects of hBN orientation and contents on the surface flashover performances of oriented hBN composites are investigated.The isothermal surface potential decay of the oriented hBN composites was also studied.It is found that the charge transportation could be adjusted by the hBN orientation,thus regulating surface flashover strength.The DC flashover voltage of the in-plane oriented hBN composites with a thickness of 15μm reached the maximum of 27.6 kV at the hBN loading of 20 wt%,14.5%higher than that of the pure resin.The carrier mobility of out-of-plane oriented hBN composites is about three times greater than that of the in-plane oriented composites,indicating that the charges are easily transported along the hBN basal plane.The larger carrier mobility causes charge dissipation in composites near the electrode at the hBN basal plane parallel to the axis of electrodes and inhibits the distortion of the surface electric field on the composites,thus enhancing the surface flashover.Consequently,developing oriented insulators for highvoltage applications and enabling an optimum insulation design would be beneficial because of the compactness and high reliability of power apparatus for use in power grids. 展开更多
关键词 compositeS surface BORON
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Rational design and synthesis of Cr_(1-x)Te/Ag_(2)Te composites for solid-state thermoelectromagnetic cooling near room temperature
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作者 孙笑晨 谢承昊 +3 位作者 陈思汗 万京伟 谭刚健 唐新峰 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期580-586,共7页
Materials with both large magnetocaloric response and high thermoelectric performance are of vital importance for all-solid-state thermoelectromagnetic cooling.These two properties,however,hardly coexist in single pha... Materials with both large magnetocaloric response and high thermoelectric performance are of vital importance for all-solid-state thermoelectromagnetic cooling.These two properties,however,hardly coexist in single phase materials except previously reported hexagonal Cr_(1-x)Te half metal where a relatively high magnetic entropy change(-△S_(M))of~2.4 J·kg^(-1)·K^(-1)@5 T and a moderate thermoelectric figure of merit(ZT)of~1.2×10^(-2)@300 K are simultaneously recorded.Herein we aim to increase the thermoelectric performance of Cr_(1-x)Te by compositing with semiconducting Ag_(2)Te.It is discovered that the in-situ synthesis of Cr_(1-x)Te/Ag_(2)Te composites by reacting their constitute elements above melting temperatures is unsuccessful because of strong phase competition.Specifically,at elevated temperatures(T>800 K),Cr_(1-x)Te has a much lower deformation energy than Ag_(2)Te and tends to become more Cr-deficient by capturing Te from Ag_(2)Te.Therefore,Ag is insufficiently reacted and as a metal it deteriorates ZT.We then rationalize the synthesis of Cr_(1-x)Te/Ag_(2)Te composites by ex-situ mix of the pre-prepared Cr_(1-x)Te and Ag_(2)Te binary compounds followed by densification at a low sintering temperature of 573 K under a pressure of 3.5 GPa.We show that by compositing with 7 mol%Ag_(2)Te,the Seebeck coefficient of Cr_(1-x)Te is largely increased while the lattice thermal conductivity is considerably reduced,leading to 72%improvement of ZT.By comparison,-△S_(M)is only slightly reduced by 10%in the composite.Our work demonstrates the potential of Cr_(1-x)Te/Ag_(2)Te composites for thermoelectromagnetic cooling. 展开更多
关键词 thermoelectromagnetic cooling thermoelectric MAGNETOCALORIC composite chromium telluride
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The Evaluation of the Dietary Habits Influence on the Microhardness of Gingiva-Coloured Composite and Acrylic Denture Base Materials
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作者 Hayriye Yasemin Yay Kuscu Ilhan Gun 《Advances in Nanoparticles》 CAS 2024年第3期79-95,共17页
Purpose: The study investigated the impact of dietary habits, specifically soda, milk kefir, water kefir, almond milk, and distilled water (control) consumption, on the microhardness of gingiva-coloured composite and ... Purpose: The study investigated the impact of dietary habits, specifically soda, milk kefir, water kefir, almond milk, and distilled water (control) consumption, on the microhardness of gingiva-coloured composite and acrylic denture bases. Methods: Materials included gingiva-coloured composite (Fusion Universal G1), acrylic (Imicryl), and subdivided Procryla group. Subgroups comprised 15 and 30-minute heat polymerized (Pro15, Pro30), and 1 wt% (Pro1Z) and 3 wt% (Pro3Z) zirconium added groups. Immersed in beverages for 1, 7, and 14 days, pH and microhardness were assessed. SEM examined random samples. Statistical analysis used repeated measures ANOVA, and post hoc tests (p Results: The gingiva-coloured composites displayed noteworthy time-associated microhardness changes (p 0.05). Despite variable pH levels in beverages, no substantial group interaction effects were observed (p > 0.05). Initial microhardness rankings shifted after a 14-day immersion. Conclusions: Gingiva-coloured composite exhibited the highest microhardness pre- and post-immersion, followed by Procryla30 and Imicryl groups. . 展开更多
关键词 Gingiva-Coloured composite ACRYLIC Denture Base Materials Hybrid Prosthesis MICROHARDNESS Beverages
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Experimental Investigation of the Anisotropic Thermal Conductivity of C/SiC Composite Thin Slab
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作者 毋克凡 张虎 唐桂华 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第3期48-60,共13页
Fiber-reinforced composites possess anisotropic mechanical and heat transfer properties due to their anisotropic fibers and structure distribution.In C/Si C composites,the out-of-plane thermal conductivity has mainly ... Fiber-reinforced composites possess anisotropic mechanical and heat transfer properties due to their anisotropic fibers and structure distribution.In C/Si C composites,the out-of-plane thermal conductivity has mainly been studied,whereas the in-plane thermal conductivity has received less attention due to their limited thickness. 展开更多
关键词 compositeS C/Si ANISOTROPIC
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Comparison among the UECM Model, and the Composite Model in Forecasting Malaysian Imports
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作者 Mohamed A. H. Milad Hanan Moh. B. Duzan 《Open Journal of Statistics》 2024年第2期163-178,共16页
For more than a century, forecasting models have been crucial in a variety of fields. Models can offer the most accurate forecasting outcomes if error terms are normally distributed. Finding a good statistical model f... For more than a century, forecasting models have been crucial in a variety of fields. Models can offer the most accurate forecasting outcomes if error terms are normally distributed. Finding a good statistical model for time series predicting imports in Malaysia is the main target of this study. The decision made during this study mostly addresses the unrestricted error correction model (UECM), and composite model (Combined regression—ARIMA). The imports of Malaysia from the first quarter of 1991 to the third quarter of 2022 are employed in this study’s quarterly time series data. The forecasting outcomes of the current study demonstrated that the composite model offered more probabilistic data, which improved forecasting the volume of Malaysia’s imports. The composite model, and the UECM model in this study are linear models based on responses to Malaysia’s imports. Future studies might compare the performance of linear and nonlinear models in forecasting. 展开更多
关键词 composite Model UECM ARIMA Forecasting MALAYSIA
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Influence of Mass Ratio of Resin and Stabilizer on Mechanical Properties of Mo Fiber-reinforced Granite Polymer Composite
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作者 张超 任秀华 +6 位作者 BA Dongzhe ZHANG Jianhua LI Jianyong GUO Mengnan GAO Yinghao WANG Guixin LI Jiayang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第4期912-920,共9页
Because inferior mechanical strength of granite polymer composite(GPC)has become the main drawback limiting its application and popularization,Mo fibers were added into(GPC)to improve its mechanical strength.Mechanica... Because inferior mechanical strength of granite polymer composite(GPC)has become the main drawback limiting its application and popularization,Mo fibers were added into(GPC)to improve its mechanical strength.Mechanical properties of matrix materials with different mass ratio of resin and stabilizer(MRRS)were investigated systematically.The influences of MRRS on interface bonding strength of Mo fiber-matrix,wettability and mechanical strength of GPC were discussed,respectively,and the theoretical calculation result of MRRS k was obtained,with the optimal value of k=4.When k=4,tensile strength,tensile strain and fracture stress of the cured resin achieve the maximum values.But for k=7,the corresponding values reach the minimum.With the increase of MRRS k,surface free energy of the cured resin first increases and then decreases,while contact angles between Mo sample and matrix have displayed the opposite trend.Wettability of resin to Mo fiber is the best at k=4.Pulling load of Mo fiber and interface bonding strength appear the maximum at k=4,followed by k=5,k=3 the third,and k=7 the minimum.When k=4,mechanical properties of Mo fiber-reinforced GPC are optimal,which is consistent with the result of theoretical calculation.This study is of great significance to get better component formulas of Mo fiber reinforced GPC and to improve its application in machine tools. 展开更多
关键词 polymer composite FIBER mechanical strength interface bonding
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