The formation of humins hampers the large-scale production of 5-hydroxymethylfurfural(HMF)in biorefinery.Here,a detailed reaction network of humin formation at the initial stage of fructose-to-HMF dehydration in water...The formation of humins hampers the large-scale production of 5-hydroxymethylfurfural(HMF)in biorefinery.Here,a detailed reaction network of humin formation at the initial stage of fructose-to-HMF dehydration in water is delineated by combined experimental,spectroscopic,and theoretical studies.Three bimolecular reaction pathways to build up soluble humins are demonstrated.That is,the intermolecular etherification of β-furanose at room temperature initiates the C12 path,whereas the C-C cleavage of a-furanose at 130-150℃ leads to C11 path,and that of open-chain fructose at 180℃ to C11' path.The successive intramolecular dehydrations and condensations of the as-formed bimolecular intermediates lead to three types of soluble humins.We show that the C12 path could be restrained by using HCl or AlCl_(3) catalyst,and both the C12 and C110 paths could be effectively inhibited by adding THF as a co-solvent or accelerating heating rate via microwave heating.展开更多
Metal oxide and carbide strengthening molybdenum(Mo)alloys have been designed as promising ad-vanced materials in refractory metals to solve some of the core engineering problems in superalloy ap-plications.Hence,ther...Metal oxide and carbide strengthening molybdenum(Mo)alloys have been designed as promising ad-vanced materials in refractory metals to solve some of the core engineering problems in superalloy ap-plications.Hence,there is a need to summarize the results obtained and evaluate the opportunities for preparing high-performance Mo alloys by strengthening metal oxides and carbides to improve the per-formance characteristics of Mo metal materials.This paper reviews the results of the reported work con-cerning the structure and properties of Mo alloys with different metal oxide and carbide strengthening methods added to Mo matrix.The influence of the doping of La 2 O 3 and Y 2 O 3 particles,ceramic Al 2 O 3 and ZrO 2 particles,and refractory TiC and ZrC carbides particles of Mo alloys are discussed.The impacts of particle morphology,size,distribution and volume fractions of oxide and carbide are analyzed,as well as the specific features of different doping techniques for obtaining high-performance Mo alloys mate-rials.This work will guide future research on the design of high-performance refractory Mo alloys by adding oxides and carbide particles,helping to solve the core issues in the field of superalloy application research.展开更多
Aqueous zinc-ion batteries(AZIBs)have become a hotspot for electrochemical energy storage owing to the high safety,low cost,environmental friendliness,and favorable rate performance.However,the serious dissolution of ...Aqueous zinc-ion batteries(AZIBs)have become a hotspot for electrochemical energy storage owing to the high safety,low cost,environmental friendliness,and favorable rate performance.However,the serious dissolution of cathode materials in aqueous electrolytes would lead to poor cyclability,which should be addressed before commercialization.Herein,we designed a Ti-doped V_(2)O_(5) with yolk-shell microspherical structure for AZIBs.The Ti doping stabilizes the crystal structure and relieves the dissolution of V_(2)O_(5) in aqueous ZnSO_(4) electrolyte.The optimized sample,Ti_(0.2)V_(1.8)O_(4.9),delivers a high capacity(355 mAh/g at 0.05 A/g)as well as good capacity retention(89%after 2500 cycles at 1.0 A/g).This work provides an effective strategy to mitigate the dissolution of cathode material in aqueous ZnSO_(4) electrolyte for cyclability enhancement.展开更多
Xiao et al reported on the natural product sinomenine(SIN),which is a traditional Chinese medicine for treating osteoporosis via its modulation of autophagy;however,SIN was dissolved in dimethyl sulfoxide prior to adm...Xiao et al reported on the natural product sinomenine(SIN),which is a traditional Chinese medicine for treating osteoporosis via its modulation of autophagy;however,SIN was dissolved in dimethyl sulfoxide prior to administration,which is not conducive to the development of clinical injectables.By comparing solubilization techniques,including amorphisation,emulsification,micellisation,nanocrystallisation and host-vip inclusion,we found that the solubilization of SIN by host-vip inclusion can enhance solubility and improve stability and has an increased release rate and enhanced bioavailability.Therefore,we conclude that host-vip inclusion holds promise for SIN solubilization.To solubilise SIN,we selectedβ-cyclodextrin as the host agent considering its excellent biocompatibility,efficient encapsulation ability,mature preparation process and adequate drug stability.If the prerequisites of SIN-β-cyclodextrin complexes in terms of safety,efficacy,stability and the relevant laws and regulations are met,its clinical application for the treatment of osteoporosis may be achieved.展开更多
Valorization of renewable cellulose into initial platform chemicals(IPCs)generally suffers from low process efficiency owing to difficult depolymerization of recalcitrant cellulose and troublesome repolymerization of ...Valorization of renewable cellulose into initial platform chemicals(IPCs)generally suffers from low process efficiency owing to difficult depolymerization of recalcitrant cellulose and troublesome repolymerization of high-reactive intermediates to undesired humins.Herein,we report a double-protective strategy for cellulose depolymerization and orientated conversion to levulinic acid(LA),one of the important IPCs,by in-situ adding protective formaldehyde(HCHO).This approach initiates from the(hemi)acetalation of hydroxyl groups in cellulose with HCHO,causing controllable depolymerization to(hemi)acetalized glucose with increased rate kinetically and a new mechanism of its catalytic conversion to LA via(hemi)acetal-driven direct C1-C2 cleavage.As such,the cellulose-to-LA conversion is protectively proceeded with the repolymerization of reactive intermediates prevented remarkably,leading to an excellent LA yield of 87.3 mol% from high-loading microcrystalline cellulose(15.0 wt% in aqueous phase)in a biphasic solvent containing 2-methyltetrahydrofuran and water.The process efficiency,expressed as space-time yield,is improved by 3.6 fold when compared with a non-protective approach.This work highlights an advance in maximizing the utilization of biomass-derived carbons for high-efficiency production of important IPCs directly from cellulose for future biorefinery.展开更多
To address the challenges associated with multi-sided shells in traditional isogeometric analysis(IGA),this paper introduces a novel isogeometric shell method for trimmed CAD geometries based on toric surfaces and Rei...To address the challenges associated with multi-sided shells in traditional isogeometric analysis(IGA),this paper introduces a novel isogeometric shell method for trimmed CAD geometries based on toric surfaces and Reissner–Mindlin shell theory.By utilizing toric surface patches,both trimmed and untrimmed elements of the CAD surfaces are represented through a unified geometric framework,ensuring continuity and an accurate geometric description.Toric-Bernstein basis functions are employed to accurately interpolate the geometry and displacement of the trimmed shell.For singularities and corner points on the toric surface,the normal vector is defined as the unit directional vector from the center of curvature to the corresponding control point.Several numerical examples of polygonal shells are presented to evaluate the effectiveness and robustness of the proposed method.This approach significantly simplifies the treatment of trimmed shell IGA and provides a promising solution for simulating complex shell structures with intricate boundaries.展开更多
Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys ar...Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys are prone to oxidation and failure in high-temperature service environments.The preparation of a MoSi_(2) antioxidant coating is an effective method for improving the protective ability of refractory metals at high temperatures.However,although MoSi_(2) coatings have many advantages,it is difficult to meet the increasingly stringent service requirements.To address these challenges,researchers have used different elements to modify a single MoSi_(2) coating and improve its overall oxidation resistance.In this study,the roles of one or more elements(Si,B,N,Zr,Al,W,Hf,Y,Ti and Cr)in MoSi_(2) coatings are systematically reviewed.Simultaneously,the mechanism of single or multiple synergistic modification of MoSi_(2) coatings with different elements was discussed.Finally,the development prospects of MoSi_(2) coating modification of refractory metals and their alloys are discussed.展开更多
Layered rock mass of significant strength changes for adjacent layers is frequently observed in underground excavation,and dynamic loading is a prevalent scenario generated during excavation.In order to improve the dr...Layered rock mass of significant strength changes for adjacent layers is frequently observed in underground excavation,and dynamic loading is a prevalent scenario generated during excavation.In order to improve the driving efficiency and reduce engineering accidents,dynamic compression characteristics of this kind of rock mass should be understood.The dynamic properties of a layered composite rock mass are investigated through a series of rock tests and numerical simulations.The rock mass is artificially made of various proportions of sand,cement and water to control the distinct strength variations at various composite layers separated by parallel bedding planes.All rock specimens are prefabricated in a specially designed mould and then cut into 50 mm in diameter and 50 mm in height for split Hopkinson pressure bar(SHPB)dynamic compression testing.The test results reveal that increasing strain rate causes the increases of peak strength,σ_p,and the corresponding failure strain,ε_p,while the dynamic elastic modulus,E_d,remains almost unchanged.Interestingly,under the same strain rates,Ed of the composite rock specimen is found to decline first and then increase as the dip angle of bedding plane increases.The obtained rock failure patterns due to various dip angles lead to failure modes that could be classified into four categories from our dynamic tests.Also,a series of counterpart numerical simulations has been undertaken,showing that dynamic responses are in good agreement with those obtained from the SHPB tests.The numerical analysis enables us to Iook into the dynamic characteristics of the composite rock mass subjected to a broader range of strain rates and dip angles than these being tested.展开更多
基金the National Natural Science Foundation of China(No.21875149)111 project(B17030)the Basal Research Fund of the Central University.
文摘The formation of humins hampers the large-scale production of 5-hydroxymethylfurfural(HMF)in biorefinery.Here,a detailed reaction network of humin formation at the initial stage of fructose-to-HMF dehydration in water is delineated by combined experimental,spectroscopic,and theoretical studies.Three bimolecular reaction pathways to build up soluble humins are demonstrated.That is,the intermolecular etherification of β-furanose at room temperature initiates the C12 path,whereas the C-C cleavage of a-furanose at 130-150℃ leads to C11 path,and that of open-chain fructose at 180℃ to C11' path.The successive intramolecular dehydrations and condensations of the as-formed bimolecular intermediates lead to three types of soluble humins.We show that the C12 path could be restrained by using HCl or AlCl_(3) catalyst,and both the C12 and C110 paths could be effectively inhibited by adding THF as a co-solvent or accelerating heating rate via microwave heating.
基金the Outstanding Doctorate Dis-sertation Cultivation Fund of Xi’an University of Architecture and Technology(No.160842012)ScientificandTechnologicalInnova-tion Team Project of the Shaanxi Innovation Capability Support Plan,China(No.2022TD-30)+8 种基金the Fok Ying Tung Education Foun-dation(No.171101)Youth Innovation Team of Shaanxi Universi-ties(No.2019-2022)Top young talents project of“Special support program for high-level talents”in the Shaanxi Province(No.2018-2023)Major scientific and technological projects in the Shaanxi Province of China(No.2020ZDZX04-02-01)Service local spe-cial program of education department of Shaanxi province,China(No.21JC016)General Special Scientific Research Program of the Shaanxi Provincial Department of Education(No.21JK0722)the General Projects of Key R&D Program of the Shaanxi Province,China(No.2021GY-209)China Postdoctoral Science Foundation(No.2021M693878)China Postdoctoral Science Foundation(No.2021MD703866).
文摘Metal oxide and carbide strengthening molybdenum(Mo)alloys have been designed as promising ad-vanced materials in refractory metals to solve some of the core engineering problems in superalloy ap-plications.Hence,there is a need to summarize the results obtained and evaluate the opportunities for preparing high-performance Mo alloys by strengthening metal oxides and carbides to improve the per-formance characteristics of Mo metal materials.This paper reviews the results of the reported work con-cerning the structure and properties of Mo alloys with different metal oxide and carbide strengthening methods added to Mo matrix.The influence of the doping of La 2 O 3 and Y 2 O 3 particles,ceramic Al 2 O 3 and ZrO 2 particles,and refractory TiC and ZrC carbides particles of Mo alloys are discussed.The impacts of particle morphology,size,distribution and volume fractions of oxide and carbide are analyzed,as well as the specific features of different doping techniques for obtaining high-performance Mo alloys mate-rials.This work will guide future research on the design of high-performance refractory Mo alloys by adding oxides and carbide particles,helping to solve the core issues in the field of superalloy application research.
基金the National Natural Science Foundation of China(No.52102299)the Independent Innovation Project of Hubei Longzhong Laboratory(No.2022ZZ-18)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110059)the Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(No.XHT2020-003).
文摘Aqueous zinc-ion batteries(AZIBs)have become a hotspot for electrochemical energy storage owing to the high safety,low cost,environmental friendliness,and favorable rate performance.However,the serious dissolution of cathode materials in aqueous electrolytes would lead to poor cyclability,which should be addressed before commercialization.Herein,we designed a Ti-doped V_(2)O_(5) with yolk-shell microspherical structure for AZIBs.The Ti doping stabilizes the crystal structure and relieves the dissolution of V_(2)O_(5) in aqueous ZnSO_(4) electrolyte.The optimized sample,Ti_(0.2)V_(1.8)O_(4.9),delivers a high capacity(355 mAh/g at 0.05 A/g)as well as good capacity retention(89%after 2500 cycles at 1.0 A/g).This work provides an effective strategy to mitigate the dissolution of cathode material in aqueous ZnSO_(4) electrolyte for cyclability enhancement.
基金Supported by Guangdong Basic and Applied Basic Research Foundation,No.2024A1515011236General Program of Administration of Traditional Chinese Medicine of Guangdong Province,No.20241071.
文摘Xiao et al reported on the natural product sinomenine(SIN),which is a traditional Chinese medicine for treating osteoporosis via its modulation of autophagy;however,SIN was dissolved in dimethyl sulfoxide prior to administration,which is not conducive to the development of clinical injectables.By comparing solubilization techniques,including amorphisation,emulsification,micellisation,nanocrystallisation and host-vip inclusion,we found that the solubilization of SIN by host-vip inclusion can enhance solubility and improve stability and has an increased release rate and enhanced bioavailability.Therefore,we conclude that host-vip inclusion holds promise for SIN solubilization.To solubilise SIN,we selectedβ-cyclodextrin as the host agent considering its excellent biocompatibility,efficient encapsulation ability,mature preparation process and adequate drug stability.If the prerequisites of SIN-β-cyclodextrin complexes in terms of safety,efficacy,stability and the relevant laws and regulations are met,its clinical application for the treatment of osteoporosis may be achieved.
基金financially supported by the National Natural Science Foundation of China(No.22378277)111 Center(B17030)+1 种基金the Basal Research Fund of the Central University(2016SCU04B06)the technical support from the Analysis and Test Center of Sichuan University。
文摘Valorization of renewable cellulose into initial platform chemicals(IPCs)generally suffers from low process efficiency owing to difficult depolymerization of recalcitrant cellulose and troublesome repolymerization of high-reactive intermediates to undesired humins.Herein,we report a double-protective strategy for cellulose depolymerization and orientated conversion to levulinic acid(LA),one of the important IPCs,by in-situ adding protective formaldehyde(HCHO).This approach initiates from the(hemi)acetalation of hydroxyl groups in cellulose with HCHO,causing controllable depolymerization to(hemi)acetalized glucose with increased rate kinetically and a new mechanism of its catalytic conversion to LA via(hemi)acetal-driven direct C1-C2 cleavage.As such,the cellulose-to-LA conversion is protectively proceeded with the repolymerization of reactive intermediates prevented remarkably,leading to an excellent LA yield of 87.3 mol% from high-loading microcrystalline cellulose(15.0 wt% in aqueous phase)in a biphasic solvent containing 2-methyltetrahydrofuran and water.The process efficiency,expressed as space-time yield,is improved by 3.6 fold when compared with a non-protective approach.This work highlights an advance in maximizing the utilization of biomass-derived carbons for high-efficiency production of important IPCs directly from cellulose for future biorefinery.
基金the National Key Research and Development Projects(Grant Nos.2021YFB3300601,2021YFB3300603,2021YFB3300604)the Fundamental Research Funds for the Central Universities(No.DUT22QN241)is acknowledged.
文摘To address the challenges associated with multi-sided shells in traditional isogeometric analysis(IGA),this paper introduces a novel isogeometric shell method for trimmed CAD geometries based on toric surfaces and Reissner–Mindlin shell theory.By utilizing toric surface patches,both trimmed and untrimmed elements of the CAD surfaces are represented through a unified geometric framework,ensuring continuity and an accurate geometric description.Toric-Bernstein basis functions are employed to accurately interpolate the geometry and displacement of the trimmed shell.For singularities and corner points on the toric surface,the normal vector is defined as the unit directional vector from the center of curvature to the corresponding control point.Several numerical examples of polygonal shells are presented to evaluate the effectiveness and robustness of the proposed method.This approach significantly simplifies the treatment of trimmed shell IGA and provides a promising solution for simulating complex shell structures with intricate boundaries.
基金supported by the National Natural Science Foundation of China(No.52374401 and 52404409)the Key R&D Plan of Shaanxi Province(Nos.2024QCYKXJ-116 and 2023JBGS-14)+3 种基金the Scientific and Technological Innovation Team Project of Shaanxi Innovation Capability Support Plan(No.2022TD-30)Xi’an Science and Technology Plan Project(No.2023JHGXRC-0020)the“Young Talent Support Project”of China Association for Science and Technology of China.The Natural Science Foundation of Shaanxi Provincial(No.2024JC-YBQN-0367)China Postdoctoral Science Foundation(2024MD753961).
文摘Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys are prone to oxidation and failure in high-temperature service environments.The preparation of a MoSi_(2) antioxidant coating is an effective method for improving the protective ability of refractory metals at high temperatures.However,although MoSi_(2) coatings have many advantages,it is difficult to meet the increasingly stringent service requirements.To address these challenges,researchers have used different elements to modify a single MoSi_(2) coating and improve its overall oxidation resistance.In this study,the roles of one or more elements(Si,B,N,Zr,Al,W,Hf,Y,Ti and Cr)in MoSi_(2) coatings are systematically reviewed.Simultaneously,the mechanism of single or multiple synergistic modification of MoSi_(2) coatings with different elements was discussed.Finally,the development prospects of MoSi_(2) coating modification of refractory metals and their alloys are discussed.
基金supported by the National Natural Science Foundation of China(Grant No.51608174)the Programmes for Science and Technology Development of Henan Province,China(Grant No.192102310014)。
文摘Layered rock mass of significant strength changes for adjacent layers is frequently observed in underground excavation,and dynamic loading is a prevalent scenario generated during excavation.In order to improve the driving efficiency and reduce engineering accidents,dynamic compression characteristics of this kind of rock mass should be understood.The dynamic properties of a layered composite rock mass are investigated through a series of rock tests and numerical simulations.The rock mass is artificially made of various proportions of sand,cement and water to control the distinct strength variations at various composite layers separated by parallel bedding planes.All rock specimens are prefabricated in a specially designed mould and then cut into 50 mm in diameter and 50 mm in height for split Hopkinson pressure bar(SHPB)dynamic compression testing.The test results reveal that increasing strain rate causes the increases of peak strength,σ_p,and the corresponding failure strain,ε_p,while the dynamic elastic modulus,E_d,remains almost unchanged.Interestingly,under the same strain rates,Ed of the composite rock specimen is found to decline first and then increase as the dip angle of bedding plane increases.The obtained rock failure patterns due to various dip angles lead to failure modes that could be classified into four categories from our dynamic tests.Also,a series of counterpart numerical simulations has been undertaken,showing that dynamic responses are in good agreement with those obtained from the SHPB tests.The numerical analysis enables us to Iook into the dynamic characteristics of the composite rock mass subjected to a broader range of strain rates and dip angles than these being tested.
