Dynamic melt modification of polyethylene via the direct grafting of peroxide fragments shows promise for the development of processable functionalized materials.In this study,four linear low-density polyethylenes(LLD...Dynamic melt modification of polyethylene via the direct grafting of peroxide fragments shows promise for the development of processable functionalized materials.In this study,four linear low-density polyethylenes(LLDPEs)with comparable molecular weights but different short-chain branch(SCB)contents(ranging of 5-66 per 1000 carbon atoms)were modified via dynamic melt mixing using 2 wt% benzoyl peroxide at 145℃ and 50 r/min for 30 min.The influence of SCB content on the processability and structure of the resulting products was systematically investigated.All modified products exhibited good melt processability with melt flow rates(MFR)ranging from 0.46 g/10min to 1.07 g/10min.Products derived from low-SCB LLDPEs showed a lower MFR,higher cross-linking content,a larger number of long-chain branches,and a higher degree of benzoyl grafting.In contrast,those produced from high-SCB LLDPEs exhibited improved processability,reduced cross-linking,fewer long-chain branches,and lower benzoyl grafting levels.A detailed structural investigation of the soluble and insoluble fractions,which were separated using trichlorobenzene fractionation,was conducted to analyze the structural features of various modified products and demonstrate that the SCB content(i.e.,tertiary carbon density)significantly influences radical coupling during dynamic modification.Elevated tertiary carbon density,by introducing greater steric hindrance,suppresses radical coupling during dynamic modification,thereby reducing the efficiency of both crosslinking and peroxide fragment grafting.These findings provide new insights into the structure-reactivity relationships in peroxide-induced polyethylene modification and lay the foundation for tailoring material properties via dynamic processing.展开更多
Zr modification is an effective method for improving hot-cracking resistance and elevated-temperature mechanical properties during laser powder bed fusion(L-PBF)of traditional medium and high strength wrought aluminum...Zr modification is an effective method for improving hot-cracking resistance and elevated-temperature mechanical properties during laser powder bed fusion(L-PBF)of traditional medium and high strength wrought aluminum alloys.This study investigated the l-PBF processability and elevated-temperature mechanical properties of a Zr-modified 2024Al alloy.It was found that the hot-cracking susceptibility increased with the increased scanning speed,which was in reasonable agreement with the modified Rappaz-Drezet-Gremaud criterion.Furthermore,the primary L1_(2)-Al_(3)Zr precipitates,which acted as ef-ficient nucleation sites,precipitated at the fusion boundary of the melt pool,leading to the formation of a heterogeneous grain structure.The yield strength(YS)of the as-fabricated samples at 150,250,and 350℃was 363,210,and 48 MPa,respectively.Despite the slight decrease to 360 MPa of the YS when tested at 150℃,owing to the additional precipitate strengthening from the L1_(2)-Al_(3)Zr precipitates,the YS achieved yield strengths of 253 and 69 MPa,an increase of 20.5%and 30.4%,when tested at 250 and 350℃,respectively.The yield strengths in both the as-fabricated and T6-treated conditions tested at 150 and 250℃were comparable to those of casting Al-Cu-Mg-Ag alloys and superior to those of traditionally heat-resistant 2219-T6 and 2618-T6 of Al-Cu alloys.展开更多
The effect of pan-milling on morphological structure,processability and properties of PVC was studied throughSEM,FTIR,granulometer,GPC and mechanical properties test in the hope of gaining ease in operation,needless o...The effect of pan-milling on morphological structure,processability and properties of PVC was studied throughSEM,FTIR,granulometer,GPC and mechanical properties test in the hope of gaining ease in operation,needless ofplasticizers,a clean and efficient route for improving the processability of PVC through stress-induced reactions,fulfilling the idea of“plasticizing PVC by itself”.The experimental results show that during pan-milling at ambienttemperature,within 2-3 min,the microcrystalline structure of PVC becomes indistinct,the grain size of PVC is reducedfrom 130-160 μm to 1-50 μm the molecular weight of PVC is slightly decreased,the variation of molecular weightdistribution is indistinct,the plasticizing time and torque at balance drop a great deal from 71-132 s to 31-33 s and from18.2-22.1 Nm to 14.7-18.4 Nm,respectively,the processability of PVC is markedly improved,and the mechanicalproperties get enhanced too.展开更多
The purpose of this article is twofold.First,it explores the order of the development of nominal and verbal gender of Amharic,which is one of the Ethio-Semitic languages.Second,it provides empirical evidence for the t...The purpose of this article is twofold.First,it explores the order of the development of nominal and verbal gender of Amharic,which is one of the Ethio-Semitic languages.Second,it provides empirical evidence for the typological plausibility of processability theory(PT).In fact,PT has been tested in typologically different languages(e.g.,English,Italian,and Japan);however,it does not have any validation from Ethiopian languages in general and Ethio-Semitic languages in particular yet.Relevant data was collected from sixteen respondents via picture description tasks,short storytelling,interviews,story re-telling,and spot the difference tasks.Distributional analysis was conducted for the analysis,and the point of emergence of target structures was determined using the emergence criteria.Accordingly,the result shows that the development of gender assignment is compatible with processability theory’s predictions in that lexical procedure precedes phrasal procedure,which is followed by S-procedure.Moreover,the masculine gender emerged earlier than its feminine counterpart at all developmental stages.However,subject agreement markers in pro-drop context emerged at stage two preceding subject verb agreement.This finding is against processability theory’s claim that suggests subject agreement markers only emerge at stage four of the processability hierarchy disregarding their stages of development in pro-drop context in particular.展开更多
Metal-organic frameworks(MOFs) show great potential for various applications, but many of them suffer from the drawbacks of hydrolysis propensity and poor processability. Herein, we employ polymers of intrinsic microp...Metal-organic frameworks(MOFs) show great potential for various applications, but many of them suffer from the drawbacks of hydrolysis propensity and poor processability. Herein, we employ polymers of intrinsic microporosity(PIMs) with hydrophobic pores to decorate MOFs toward substantially improved water stability and shapeability. Through simple PIM-1 decoration, the sub-5 nm polymer layers can be uniformly deposited on MOF surfaces with almost no deterioration in porosity. Owing to the existence of superhydrophobic coating and the obstruction of water entrance into MOFs, the PIM-1 coated Cu BTC exhibits impressive water resistance and excellent pore preservation ability after exposure in water, even in acidic and alkaline solutions. Moreover, polymer decoration improves the processability of MOFs, while various MOF/PIM-1 bulk wafers and oil-water separators can be obtained straightforwardly.展开更多
Achieving long-term stability and scalable manufacturing under ambient conditions is crucial for the advancement of organic solar cells(OSCs).Additive engineering has proven effective in optimizing active layer morpho...Achieving long-term stability and scalable manufacturing under ambient conditions is crucial for the advancement of organic solar cells(OSCs).Additive engineering has proven effective in optimizing active layer morphology and improving device performance.In this study,we systematically investigated the effects of three cyclosiloxane additives(c-3 Si,c-4 Si,and c-5 Si)for the first time.Due to enhanced crystallinity,optimal phase separation,and improved charge carrier dynamics,the c-5 Si-processed device exhibited the champion efficiency,outperforming those of control,c-3 Si and c-4 Si devices.Specifically,the PM6:Y6-based device with c-5 Si treatment achieved an impressive PCE of 18.26%.Furthermore,c-5 Si processed PM6:L8-BO and D18:L8-BO active layers showed PCEs of 19.35%and 19.70%,respectively,highlighting their universal potential for high-performance devices.Additive c-5 Si improved OSC stability,significantly extending the T_(80)lifetime from 43 to 205 h under 80℃heating and one sun illumination in the meantime.Additive c-5 Si also enabled the fabrication of high-performance active layers under high-humidity conditions(90%RH),providing an effective solution for air processing of OSCs.This work provides a simple yet effective strategy involving cyclosiloxane additives for manipulating active layer morphology,which advances the development of efficient,stable,and scalable OSCs for commercial applications.展开更多
There is usually a trade-off between the mechanical properties and processability of polymers because the mechanisms underlying these properties are mutually exclusive.Herein,we discovered that rationally designed cro...There is usually a trade-off between the mechanical properties and processability of polymers because the mechanisms underlying these properties are mutually exclusive.Herein,we discovered that rationally designed crosslinking can simultaneously enhance both the mechanical properties and processability of polymers.To achieve this,a dynamically dissociable crosslinker was designed using a reversible Diels-Alder reaction that forms a stable covalently crosslinked network from the linear polymer.During processing,the crosslinked network dissociates to release a small-molecule crosslinking agent,which increases the free volume of the polymer and weakens the non-covalent interactions between the molecular chains.Consequently,the polymer exhibits superior processing performance compared to its linear polymer counterpart.A polyurethane model was designed to demonstrate this strategy.After crosslinking,the strength and toughness of the polyurethane increased significantly compared to those of the linear polyurethane counterpart.Additionally,the solid-liquid transition temperature of the polyurethane decreased from 149℃ to 118℃,and the processing viscosity decreased by 48%.An application of this technology was demonstrated by producing fibers with the highest tensile strength(78.7 MPa)at the lowest processing temperature(125℃)reported for meltspun crosslinked fibers.展开更多
Ultra-high molecular weight polyethylene(UHMWPE,M_(w)>10^(6)g mol^(−1))has been prepared using slurryphase titanium permethylindenyl-phenoxy(PHENI^(*))catalysts.Four strategies have been investigated for improving ...Ultra-high molecular weight polyethylene(UHMWPE,M_(w)>10^(6)g mol^(−1))has been prepared using slurryphase titanium permethylindenyl-phenoxy(PHENI^(*))catalysts.Four strategies have been investigated for improving the melt processability of UHMWPE,which is the chief limiting factor to the applications of this high-performance polymer.1)Active site engineering was used to explore the entanglement density in the resulting polymer,with substantially disentangled PE identified through thermal and rheological characterisation.2)Hydrogen and ZnEt2 were employed as chain transfer agents to modulate the polyethylene molecular weight and distribution(MWD).A sequential reactivity protocol using ZnEt2 was able to produce bimodal UHMWPE with improved processability.3)MWD tuning was further investigated using multisite catalysts,with the reaction conditions and Ti:Zr ratio able to control MWD to essentially arbitrary shapes.The inclusion of low molecular weight fractions into UHMWPE improves the processability without compromising mechanical characteristics.4)Polymer-reinforced composite blends of UHMWPE with either HDPE or LDPE as a highly processable matrix were extruded and explored,with polymer miscibility and mechanical properties studied in detail.展开更多
Inorganic semiconductors are widely used in many fields such as information,energy,and electronics due to their rich functionalities.The chemical bonds in inorganic semiconductors are usually directional covalent bond...Inorganic semiconductors are widely used in many fields such as information,energy,and electronics due to their rich functionalities.The chemical bonds in inorganic semiconductors are usually directional covalent bonds,which inhibit the movement of dislocations.Thus,being different with metals and alloys,inorganic semiconductors are usually brittle at room temperature,with very small strain below 1%and poor machinability[1].Many metalworking techniques,such as the cold-forming processing,which is a crucial means for the cost-effective production of metal and alloy parts,cannot be applied to most inorganic semiconductors,greatly limiting their low-cost fabrication and applications in flexible electronics.展开更多
一、作为哲学的AI for Process(一)郭为的哲学思想1.郭为是谁郭为是谁?他是一位哲学家。顺便说,他同时还领导着神州数码。为什么说郭为是哲学家呢?因为他在著作中谈到高深的哲学,如“数据如水,奔流不息,无界融合”。他引述古希腊哲学家...一、作为哲学的AI for Process(一)郭为的哲学思想1.郭为是谁郭为是谁?他是一位哲学家。顺便说,他同时还领导着神州数码。为什么说郭为是哲学家呢?因为他在著作中谈到高深的哲学,如“数据如水,奔流不息,无界融合”。他引述古希腊哲学家赫拉克利特所说的“万物流转”,又说“你不能两次踏进同一条河流,因为新的水不断地流过你的身旁”,他所表达的意思是“世界上唯一不变的就是变化”。展开更多
Biomass-based hydrocarbon fuels,as one of the alternatives to traditional fossil fuels,have attracted considerable attention in the energy field due to their renewability and environmental benefits.This article provid...Biomass-based hydrocarbon fuels,as one of the alternatives to traditional fossil fuels,have attracted considerable attention in the energy field due to their renewability and environmental benefits.This article provides a systematic review of recent research progress in the chemical synthesis of biomass-based hydrocarbon fuels.It outlines the conversion pathways using feedstocks such as lipids,terpenoids,cellulose/hemicellulose,and lignin.Depending on the feedstock,various products with distinct structural characteristics can be prepared through reactions such as cyclization,condensation,and catalytic hydrogenation.Throughout the synthesis process,three key factors play a critical role:efficient catalyst development,production process optimization,and computational-chemistry-based molecular design.Finally,the article discusses future perspectives for biomass-based hydrocarbon fuel synthesis research.展开更多
To investigate the influence of Al-Zn-Mg-Cu alloy with as-homogenized and as-rolled initial microstructures on the tensile flow behavior,isothermal tensile tests were conducted on a GLEEBLE-3500 isothermal simulator a...To investigate the influence of Al-Zn-Mg-Cu alloy with as-homogenized and as-rolled initial microstructures on the tensile flow behavior,isothermal tensile tests were conducted on a GLEEBLE-3500 isothermal simulator at temperatures of 380-440℃and strain rates of 0.05-1 s^(−1).The Johnson-Cook model,Hensel-Spittel model,strain-compensated Arrhenius model,and critical fracture strain model were established.Results show that through the evaluation of the models using the correlation coefficient(R)and the average absolute relative error,the strain-compensated Arrhenius model can represent the flow behavior of the alloy more accurately.Shear bands are more pronounced in the as-homogenized specimens,whereas dynamic recrystallization is predominantly observed in as-rolled specimens.Fracture morphology analysis reveals that a mixed fracture mechanism is prevalent in the as-homogenized specimen,whereas a ductile fracture mechanism is predominant in the as-rolled specimen.The processing maps indicate that the unstable region is reduced in the as-rolled specimens compared with that in the as-homogenized specimens.The optimal hot working windows for the as-homogenized and as-rolled specimens are determined as 410-440℃/0.14-1 s^(−1)and 380-400℃/0.05-0.29 s^(−1),respectively.展开更多
Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim ...Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of significant,novel,and high-impact research in the fields of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics.展开更多
Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim ...Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of signifi cant,novel,and high-impact research in the fi elds of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics.展开更多
The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from...The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from 0.001 s^(-1) to 1 s^(-1).The results show that the addition of Sn promotes dynamic recrystallization(DRX),and CaMgSn phases can act as nucleation sites during the compression deformation.Flow stress increases with increasing the strain rate and decreasing the temperature.Both the ZM61-0.5Ca and ZMT612-0.5Ca alloys exhibit obvious DRX characteristics.CaMgSn phases can effectively inhibit dislocation motion with the addition of Sn,thus increasing the peak fl ow stress of the alloy.The addition of Sn increases the hot deformation activation energy of the ZM61-0.5Ca alloy from 199.654 kJ/mol to 276.649 kJ/mol,thus improving the thermal stability of the alloy.For the ZMT612-0.5Ca alloy,the optimal hot deformation parameters are determined to be a deformation temperature range of 350–400℃and a strain rate range of 0.001–0.01 s^(-1).展开更多
The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF...The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.展开更多
Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durabili...Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durability,and corrosion resistance.These metals have body-centered cubic crystal structure,characterized by limited slip systems and impeded dislocation motion,resulting in significant low-temperature brittleness,which poses challenges for the conventional processing.Additive manufacturing technique provides an innovative approach,enabling the production of intricate parts without molds,which significantly improves the efficiency of material usage.This review provides a comprehensive overview of the advancements in additive manufacturing techniques for the production of refractory metals,such as W,Ta,Mo,and Nb,particularly the laser powder bed fusion.In this review,the influence mechanisms of key process parameters(laser power,scan strategy,and powder characteristics)on the evolution of material microstructure,the formation of metallurgical defects,and mechanical properties were discussed.Generally,optimizing powder characteristics,such as sphericity,implementing substrate preheating,and formulating alloying strategies can significantly improve the densification and crack resistance of manufactured parts.Meanwhile,strictly controlling the oxygen impurity content and optimizing the energy density input are also the key factors to achieve the simultaneous improvement in strength and ductility of refractory metals.Although additive manufacturing technique provides an innovative solution for processing refractory metals,critical issues,such as residual stress control,microstructure and performance anisotropy,and process stability,still need to be addressed.This review not only provides a theoretical basis for the additive manufacturing of high-performance refractory metals,but also proposes forward-looking directions for their industrial application.展开更多
Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing addit...Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.展开更多
Digital twin technology brings more opportunities and challenges to chemical engineering in both academic and industry.A complex process could have multiple digitalization needs,including simulation,monitoring,operato...Digital twin technology brings more opportunities and challenges to chemical engineering in both academic and industry.A complex process could have multiple digitalization needs,including simulation,monitoring,operator training,etc.;thus,a hierarchical digital twin would be a comprehensive solution to that.In this study,a novel and general framework of the digital twin is proposed for operations in process industry.With the hierarchical structure,the framework can handle various tasks driven by different roles in process industry,including managers,engineers,and operators.To complete these tasks,the framework consists of three modules:OAS(Operation Analysis System),OMS(Operation Monitoring System),and OTS(Operator Training System).Each module focuses on one unique type of demand from the staff,as well as interactions among them enabling efficient data sharing.Based on the hierarchical framework,a digital twin system is applied for one complex industrial nitration process,which successfully enhances the operation efficiency and safety in several industrial scenarios with different demands.展开更多
基金financially supported by the Science and Technology Project of PetroChina Company Limited,China(No.2022DJ6314)the National Natural Science Foundation of China(No.52173056)。
文摘Dynamic melt modification of polyethylene via the direct grafting of peroxide fragments shows promise for the development of processable functionalized materials.In this study,four linear low-density polyethylenes(LLDPEs)with comparable molecular weights but different short-chain branch(SCB)contents(ranging of 5-66 per 1000 carbon atoms)were modified via dynamic melt mixing using 2 wt% benzoyl peroxide at 145℃ and 50 r/min for 30 min.The influence of SCB content on the processability and structure of the resulting products was systematically investigated.All modified products exhibited good melt processability with melt flow rates(MFR)ranging from 0.46 g/10min to 1.07 g/10min.Products derived from low-SCB LLDPEs showed a lower MFR,higher cross-linking content,a larger number of long-chain branches,and a higher degree of benzoyl grafting.In contrast,those produced from high-SCB LLDPEs exhibited improved processability,reduced cross-linking,fewer long-chain branches,and lower benzoyl grafting levels.A detailed structural investigation of the soluble and insoluble fractions,which were separated using trichlorobenzene fractionation,was conducted to analyze the structural features of various modified products and demonstrate that the SCB content(i.e.,tertiary carbon density)significantly influences radical coupling during dynamic modification.Elevated tertiary carbon density,by introducing greater steric hindrance,suppresses radical coupling during dynamic modification,thereby reducing the efficiency of both crosslinking and peroxide fragment grafting.These findings provide new insights into the structure-reactivity relationships in peroxide-induced polyethylene modification and lay the foundation for tailoring material properties via dynamic processing.
基金The work was financially supported by the National Key R&D Program of China(No.2016YFB1100100)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(No.2020-TZ-02)+3 种基金the Advance Research Projects in the Field of Manned Spaceflight(No.040302)the Shanghai Aerospace Science and Technology Innovation Fund Project(No.SAST2018-066)This work was also supported by the“Fundamental Research Funds for the Central Universities”(No.G2021KY05104)the“Natural Science Basis Research Plan in Shaanxi Province of China”(No.2022JQ-479).We would like to thank Editage(www.editage.com)for En-glish language editing.
文摘Zr modification is an effective method for improving hot-cracking resistance and elevated-temperature mechanical properties during laser powder bed fusion(L-PBF)of traditional medium and high strength wrought aluminum alloys.This study investigated the l-PBF processability and elevated-temperature mechanical properties of a Zr-modified 2024Al alloy.It was found that the hot-cracking susceptibility increased with the increased scanning speed,which was in reasonable agreement with the modified Rappaz-Drezet-Gremaud criterion.Furthermore,the primary L1_(2)-Al_(3)Zr precipitates,which acted as ef-ficient nucleation sites,precipitated at the fusion boundary of the melt pool,leading to the formation of a heterogeneous grain structure.The yield strength(YS)of the as-fabricated samples at 150,250,and 350℃was 363,210,and 48 MPa,respectively.Despite the slight decrease to 360 MPa of the YS when tested at 150℃,owing to the additional precipitate strengthening from the L1_(2)-Al_(3)Zr precipitates,the YS achieved yield strengths of 253 and 69 MPa,an increase of 20.5%and 30.4%,when tested at 250 and 350℃,respectively.The yield strengths in both the as-fabricated and T6-treated conditions tested at 150 and 250℃were comparable to those of casting Al-Cu-Mg-Ag alloys and superior to those of traditionally heat-resistant 2219-T6 and 2618-T6 of Al-Cu alloys.
基金Subsidized by the Special Funds for Major State Basic Research Projects of China(Contract/grant number:199064809)
文摘The effect of pan-milling on morphological structure,processability and properties of PVC was studied throughSEM,FTIR,granulometer,GPC and mechanical properties test in the hope of gaining ease in operation,needless ofplasticizers,a clean and efficient route for improving the processability of PVC through stress-induced reactions,fulfilling the idea of“plasticizing PVC by itself”.The experimental results show that during pan-milling at ambienttemperature,within 2-3 min,the microcrystalline structure of PVC becomes indistinct,the grain size of PVC is reducedfrom 130-160 μm to 1-50 μm the molecular weight of PVC is slightly decreased,the variation of molecular weightdistribution is indistinct,the plasticizing time and torque at balance drop a great deal from 71-132 s to 31-33 s and from18.2-22.1 Nm to 14.7-18.4 Nm,respectively,the processability of PVC is markedly improved,and the mechanicalproperties get enhanced too.
文摘The purpose of this article is twofold.First,it explores the order of the development of nominal and verbal gender of Amharic,which is one of the Ethio-Semitic languages.Second,it provides empirical evidence for the typological plausibility of processability theory(PT).In fact,PT has been tested in typologically different languages(e.g.,English,Italian,and Japan);however,it does not have any validation from Ethiopian languages in general and Ethio-Semitic languages in particular yet.Relevant data was collected from sixteen respondents via picture description tasks,short storytelling,interviews,story re-telling,and spot the difference tasks.Distributional analysis was conducted for the analysis,and the point of emergence of target structures was determined using the emergence criteria.Accordingly,the result shows that the development of gender assignment is compatible with processability theory’s predictions in that lexical procedure precedes phrasal procedure,which is followed by S-procedure.Moreover,the masculine gender emerged earlier than its feminine counterpart at all developmental stages.However,subject agreement markers in pro-drop context emerged at stage two preceding subject verb agreement.This finding is against processability theory’s claim that suggests subject agreement markers only emerge at stage four of the processability hierarchy disregarding their stages of development in pro-drop context in particular.
基金financially supported by National Natural Science Foundation of China (No. 51708252)Guangdong Basic and Applied Basic Research Foundation (Nos. 2020B1515120036,2021A1515010187)。
文摘Metal-organic frameworks(MOFs) show great potential for various applications, but many of them suffer from the drawbacks of hydrolysis propensity and poor processability. Herein, we employ polymers of intrinsic microporosity(PIMs) with hydrophobic pores to decorate MOFs toward substantially improved water stability and shapeability. Through simple PIM-1 decoration, the sub-5 nm polymer layers can be uniformly deposited on MOF surfaces with almost no deterioration in porosity. Owing to the existence of superhydrophobic coating and the obstruction of water entrance into MOFs, the PIM-1 coated Cu BTC exhibits impressive water resistance and excellent pore preservation ability after exposure in water, even in acidic and alkaline solutions. Moreover, polymer decoration improves the processability of MOFs, while various MOF/PIM-1 bulk wafers and oil-water separators can be obtained straightforwardly.
基金supported by the National Natural Science Foundation of China(22179040)the Basic and Applied Basic Research Major Program of Guangdong Province(2019B030302007)the Guangdong Basic and Applied Basic Research Foundation(2024A1515012693)。
文摘Achieving long-term stability and scalable manufacturing under ambient conditions is crucial for the advancement of organic solar cells(OSCs).Additive engineering has proven effective in optimizing active layer morphology and improving device performance.In this study,we systematically investigated the effects of three cyclosiloxane additives(c-3 Si,c-4 Si,and c-5 Si)for the first time.Due to enhanced crystallinity,optimal phase separation,and improved charge carrier dynamics,the c-5 Si-processed device exhibited the champion efficiency,outperforming those of control,c-3 Si and c-4 Si devices.Specifically,the PM6:Y6-based device with c-5 Si treatment achieved an impressive PCE of 18.26%.Furthermore,c-5 Si processed PM6:L8-BO and D18:L8-BO active layers showed PCEs of 19.35%and 19.70%,respectively,highlighting their universal potential for high-performance devices.Additive c-5 Si improved OSC stability,significantly extending the T_(80)lifetime from 43 to 205 h under 80℃heating and one sun illumination in the meantime.Additive c-5 Si also enabled the fabrication of high-performance active layers under high-humidity conditions(90%RH),providing an effective solution for air processing of OSCs.This work provides a simple yet effective strategy involving cyclosiloxane additives for manipulating active layer morphology,which advances the development of efficient,stable,and scalable OSCs for commercial applications.
基金supported by the National Key Research and Development Program of China(2021YFC2101800)the National Natural Science Foundation of China(52473004,52173117)+1 种基金the Science and Technology Commission of Shanghai Municipality(20DZ2254900)the Fundamental Research Funds for the Central Universities(CUSF-DH-T-2024005)。
文摘There is usually a trade-off between the mechanical properties and processability of polymers because the mechanisms underlying these properties are mutually exclusive.Herein,we discovered that rationally designed crosslinking can simultaneously enhance both the mechanical properties and processability of polymers.To achieve this,a dynamically dissociable crosslinker was designed using a reversible Diels-Alder reaction that forms a stable covalently crosslinked network from the linear polymer.During processing,the crosslinked network dissociates to release a small-molecule crosslinking agent,which increases the free volume of the polymer and weakens the non-covalent interactions between the molecular chains.Consequently,the polymer exhibits superior processing performance compared to its linear polymer counterpart.A polyurethane model was designed to demonstrate this strategy.After crosslinking,the strength and toughness of the polyurethane increased significantly compared to those of the linear polyurethane counterpart.Additionally,the solid-liquid transition temperature of the polyurethane decreased from 149℃ to 118℃,and the processing viscosity decreased by 48%.An application of this technology was demonstrated by producing fibers with the highest tensile strength(78.7 MPa)at the lowest processing temperature(125℃)reported for meltspun crosslinked fibers.
基金funding from the Engineering and Physical Sciences Research Council Impact Acceleration Account(EP/X525777/1).
文摘Ultra-high molecular weight polyethylene(UHMWPE,M_(w)>10^(6)g mol^(−1))has been prepared using slurryphase titanium permethylindenyl-phenoxy(PHENI^(*))catalysts.Four strategies have been investigated for improving the melt processability of UHMWPE,which is the chief limiting factor to the applications of this high-performance polymer.1)Active site engineering was used to explore the entanglement density in the resulting polymer,with substantially disentangled PE identified through thermal and rheological characterisation.2)Hydrogen and ZnEt2 were employed as chain transfer agents to modulate the polyethylene molecular weight and distribution(MWD).A sequential reactivity protocol using ZnEt2 was able to produce bimodal UHMWPE with improved processability.3)MWD tuning was further investigated using multisite catalysts,with the reaction conditions and Ti:Zr ratio able to control MWD to essentially arbitrary shapes.The inclusion of low molecular weight fractions into UHMWPE improves the processability without compromising mechanical characteristics.4)Polymer-reinforced composite blends of UHMWPE with either HDPE or LDPE as a highly processable matrix were extruded and explored,with polymer miscibility and mechanical properties studied in detail.
文摘Inorganic semiconductors are widely used in many fields such as information,energy,and electronics due to their rich functionalities.The chemical bonds in inorganic semiconductors are usually directional covalent bonds,which inhibit the movement of dislocations.Thus,being different with metals and alloys,inorganic semiconductors are usually brittle at room temperature,with very small strain below 1%and poor machinability[1].Many metalworking techniques,such as the cold-forming processing,which is a crucial means for the cost-effective production of metal and alloy parts,cannot be applied to most inorganic semiconductors,greatly limiting their low-cost fabrication and applications in flexible electronics.
文摘一、作为哲学的AI for Process(一)郭为的哲学思想1.郭为是谁郭为是谁?他是一位哲学家。顺便说,他同时还领导着神州数码。为什么说郭为是哲学家呢?因为他在著作中谈到高深的哲学,如“数据如水,奔流不息,无界融合”。他引述古希腊哲学家赫拉克利特所说的“万物流转”,又说“你不能两次踏进同一条河流,因为新的水不断地流过你的身旁”,他所表达的意思是“世界上唯一不变的就是变化”。
基金Support by National Natural Science Foundation of China(22127802,22573091)the HY Action(62402010305)。
文摘Biomass-based hydrocarbon fuels,as one of the alternatives to traditional fossil fuels,have attracted considerable attention in the energy field due to their renewability and environmental benefits.This article provides a systematic review of recent research progress in the chemical synthesis of biomass-based hydrocarbon fuels.It outlines the conversion pathways using feedstocks such as lipids,terpenoids,cellulose/hemicellulose,and lignin.Depending on the feedstock,various products with distinct structural characteristics can be prepared through reactions such as cyclization,condensation,and catalytic hydrogenation.Throughout the synthesis process,three key factors play a critical role:efficient catalyst development,production process optimization,and computational-chemistry-based molecular design.Finally,the article discusses future perspectives for biomass-based hydrocarbon fuel synthesis research.
文摘To investigate the influence of Al-Zn-Mg-Cu alloy with as-homogenized and as-rolled initial microstructures on the tensile flow behavior,isothermal tensile tests were conducted on a GLEEBLE-3500 isothermal simulator at temperatures of 380-440℃and strain rates of 0.05-1 s^(−1).The Johnson-Cook model,Hensel-Spittel model,strain-compensated Arrhenius model,and critical fracture strain model were established.Results show that through the evaluation of the models using the correlation coefficient(R)and the average absolute relative error,the strain-compensated Arrhenius model can represent the flow behavior of the alloy more accurately.Shear bands are more pronounced in the as-homogenized specimens,whereas dynamic recrystallization is predominantly observed in as-rolled specimens.Fracture morphology analysis reveals that a mixed fracture mechanism is prevalent in the as-homogenized specimen,whereas a ductile fracture mechanism is predominant in the as-rolled specimen.The processing maps indicate that the unstable region is reduced in the as-rolled specimens compared with that in the as-homogenized specimens.The optimal hot working windows for the as-homogenized and as-rolled specimens are determined as 410-440℃/0.14-1 s^(−1)and 380-400℃/0.05-0.29 s^(−1),respectively.
文摘Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of significant,novel,and high-impact research in the fields of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics.
文摘Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of signifi cant,novel,and high-impact research in the fi elds of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics.
基金Sichuan Science and Technology Program(2025ZNSFSC1341)Fundamental Research Funds for the Central Universities(J2022-090,25CAFUC04087)。
文摘The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from 0.001 s^(-1) to 1 s^(-1).The results show that the addition of Sn promotes dynamic recrystallization(DRX),and CaMgSn phases can act as nucleation sites during the compression deformation.Flow stress increases with increasing the strain rate and decreasing the temperature.Both the ZM61-0.5Ca and ZMT612-0.5Ca alloys exhibit obvious DRX characteristics.CaMgSn phases can effectively inhibit dislocation motion with the addition of Sn,thus increasing the peak fl ow stress of the alloy.The addition of Sn increases the hot deformation activation energy of the ZM61-0.5Ca alloy from 199.654 kJ/mol to 276.649 kJ/mol,thus improving the thermal stability of the alloy.For the ZMT612-0.5Ca alloy,the optimal hot deformation parameters are determined to be a deformation temperature range of 350–400℃and a strain rate range of 0.001–0.01 s^(-1).
基金National Natural Science Foundation of China(11875039)Shanxi Scholarship Council of China(2023-033)+2 种基金Fundamental Research Program of Shanxi Province(202303021221071)China Baowu Low Carbon Metallurgical Innovation Foundation(2022)2023 Anhui Major Industrial Innovation Plan Project。
文摘The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.
基金National MCF Energy R&D Program(2024YFE03260300)。
文摘Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durability,and corrosion resistance.These metals have body-centered cubic crystal structure,characterized by limited slip systems and impeded dislocation motion,resulting in significant low-temperature brittleness,which poses challenges for the conventional processing.Additive manufacturing technique provides an innovative approach,enabling the production of intricate parts without molds,which significantly improves the efficiency of material usage.This review provides a comprehensive overview of the advancements in additive manufacturing techniques for the production of refractory metals,such as W,Ta,Mo,and Nb,particularly the laser powder bed fusion.In this review,the influence mechanisms of key process parameters(laser power,scan strategy,and powder characteristics)on the evolution of material microstructure,the formation of metallurgical defects,and mechanical properties were discussed.Generally,optimizing powder characteristics,such as sphericity,implementing substrate preheating,and formulating alloying strategies can significantly improve the densification and crack resistance of manufactured parts.Meanwhile,strictly controlling the oxygen impurity content and optimizing the energy density input are also the key factors to achieve the simultaneous improvement in strength and ductility of refractory metals.Although additive manufacturing technique provides an innovative solution for processing refractory metals,critical issues,such as residual stress control,microstructure and performance anisotropy,and process stability,still need to be addressed.This review not only provides a theoretical basis for the additive manufacturing of high-performance refractory metals,but also proposes forward-looking directions for their industrial application.
基金National Key Research and Development Program of China(2022YFB4600902)Shandong Provincial Science Foundation for Outstanding Young Scholars(ZR2024YQ020)。
文摘Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.
基金support of the“Pioneer”and“Leading Goose”Research&Development Program of Zhejiang(2024C01028)the State Key Laboratory of Industrial Control Technology,China(ICT2024C04)are gratefully acknowledged.
文摘Digital twin technology brings more opportunities and challenges to chemical engineering in both academic and industry.A complex process could have multiple digitalization needs,including simulation,monitoring,operator training,etc.;thus,a hierarchical digital twin would be a comprehensive solution to that.In this study,a novel and general framework of the digital twin is proposed for operations in process industry.With the hierarchical structure,the framework can handle various tasks driven by different roles in process industry,including managers,engineers,and operators.To complete these tasks,the framework consists of three modules:OAS(Operation Analysis System),OMS(Operation Monitoring System),and OTS(Operator Training System).Each module focuses on one unique type of demand from the staff,as well as interactions among them enabling efficient data sharing.Based on the hierarchical framework,a digital twin system is applied for one complex industrial nitration process,which successfully enhances the operation efficiency and safety in several industrial scenarios with different demands.
