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
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
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
This study mainly investigated the regulatory effect of Rosa roxburghii Tratt fruit juice fermented by Lacticaseibacillus paracasei SR10-1(LAB-RRTJ)on modulating gut microbiota in dextran sulfate sodium(DSS)-induced u...This study mainly investigated the regulatory effect of Rosa roxburghii Tratt fruit juice fermented by Lacticaseibacillus paracasei SR10-1(LAB-RRTJ)on modulating gut microbiota in dextran sulfate sodium(DSS)-induced ulcerative colitis in mice.Compared to control group,DSS induction decreased body weight of mice,indexes of Shannon,Simpson,Chao1 and Faith_pd,and increased disease activity index(DAI)and levels of interleukin 1β(IL-1β),IL-6,tumor necrosis factorα(TNF-α)and interferon-γ(IFN-γ);And this induction also led to an increase in Proteobacteria,Verrucomicrobia and Actinobacteria at phylum level,harmful bacterial species richness at genus level,and relative richness of S.sciuri,Desulfovibrio C21_c20,R.gnavus and Akkermansia muciniphila at species level,and a decrease in Firmicutes at phylum level and relative richness of B.acidifaciens in mice.LAB-RRTJ increased body weight of mice with DSS induced ulcerative colitis(UC)and indexes of Shannon,Simpson,Chao1 and Faith_pd,reduced DAI and the content of four infl ammatory factors and improved gut microbiota imbalance in DSS induced UC mice.Besides,the number of operational taxonomic units(OTUs)increased,α-diversity andβ-diversity were restored and similar to those in mice in the control group after LAB-RRTJ treatment.Compared with the positive drug treatment group,LAB-RRTJ has a better effect on regulating gut microbiota diversity in colitis mice.Correlation analysis showed that infl ammatory factors were positively correlated with harmful bacteria and negatively correlated with beneficial bacteria which commonly found in some colitis mice.Taken together,our study demonstrated that LAB-RRTJ could alleviate DSS-induced colitis in mice through the modulation of infl ammatory cytokines and gut microbiota composition.展开更多
High-efficient production of 5-hydroxymethylfurfural(HMF),a“sleeping giant”in sustainable chemistry,from cellulose depends significantly on the effective separation of cellulose from lignocellulosic biomass.Herein,w...High-efficient production of 5-hydroxymethylfurfural(HMF),a“sleeping giant”in sustainable chemistry,from cellulose depends significantly on the effective separation of cellulose from lignocellulosic biomass.Herein,we report the fractional separation of wheat straw cellulose(WSC)from wheat straw under solvothermal conditions using a mixed solvent of γ-valerolactone(GVL)and H_(2)O as the separating solvent,wherein the impacts of fractional separation parameters(solvent composition,temperature,and time)on removals of lignin and hemicellulose as well as purity and recovery of cellulose were studied by a Box-Behnken Design of response surface method.The optimization of the solvothermal parameters enabled an optimal fractional separation condition(V_(GVL):~60.0%,T:205℃,t:~1.7 h)that led to a higher purity(89.4%)and recovery(86.7%)of cellulose in WSC.A further correlation of the removals of lignin and hemicellulose as well as purity and recovery of cellulose with the yield of HMF excluded an independent influence of the above factors.Instead,a comprehensive contribution of high fractional separation efficiency(defined as the product of cellulose purity and recovery)and low crystallinity of WSC was found to improve the HMF yield.However,the heat-and freeze-dryings of WSC after the solvothermal separation were found to lower the HMF molar yield because it re-improved the crystallinity of WSC.A high HMF molar yield of 58.6%was achieved after reacting wet-WSC in a mixed solvent of 1,4-dioxane and H_(2)O at 180℃for 20 min,which was 1.5 fold higher than that from microcrystalline cellulose.This work highlights the importance of enhancing the fractional separation efficiency of cellulose from lignocellulosic biomass while avoiding the drying process for future HMF biorefinery.展开更多
High-density carbon/carbon(C/C)composite plays a critical role in the aerospace industry owing to excellent mechanical properties and resistance to ablation.However,traditional manufacturing relies on pitch precursor ...High-density carbon/carbon(C/C)composite plays a critical role in the aerospace industry owing to excellent mechanical properties and resistance to ablation.However,traditional manufacturing relies on pitch precursor and hot isostatic pressure impregnation and carbonization(HIPIC)technology,which is time-consuming and expensive.In this study,we report an innovative method utilizing polyarylacetylene(PAA)resin and ultra-high pressure impregnation and carbonization(UHPIC)technology.The extremely high char yield of PAA resin(85 wt.%)and high isotropic pressure of UHPIC(over 200 MPa)promote the densification of the composite.As a result,we achieve a high-density(1.90 g/cm^(3))C/C composite with a high degree of graphitization(81%).This composite exhibits impressive properties,including flexural strength of 146 MPa,compressive strength of 187 MPa,and thermal conductivity of 147 W/(m K).When exposed to oxyacetylene flame at 3000 K for 100 s,it displays minimal linear ablation,with a rate of 1.27×10^(-2)mm/s.This study demonstrates the exceptional graphitizable characteristic of PAA resin,setting it apart from conventional resins.Our time-saving and cost-effective approach holds significant promise for aerospace applications,particularly in harsh aerodynamic heating environments.展开更多
In response to global carbon neutrality targets,there is an urgent need for large-scale,clean hydrogen production technologies to supplant fossil fuels and underpin the establishment of a‘hydrogen economy’.The prosp...In response to global carbon neutrality targets,there is an urgent need for large-scale,clean hydrogen production technologies to supplant fossil fuels and underpin the establishment of a‘hydrogen economy’.The prospect of large-scale on-site green hydrolysis of Mg-based materials for hydrogen production has attracted wide attention.Aiming at the problems of easy formation of inert oxide layer on its surface and the production of Mg(OH)_(2) to hinder the hydrolysis process,it is urgent to explore efficient,low-cost and green modification strategies.In this work,the green modification strategy for hydrolyzing hydrogen production of Mg-based materials was summarized,and the fast initial kinetics and high hydrogen production rate could be achieved by adjusting hydrolysis medium conditions and modifying Mg-based material.The significance of hydrolytic hydrogen production technology and device development for the realization of Mg-based hydrolytic hydrogen production was evaluated.Meanwhile,this work looks forward to the future direction of hydrogen production modification by hydrolysis of Mg-based alloy,and gradually optimizes the hydrolysis performance of industrial multi-component waste Mg alloy under the premise of green hydrogen production,and proposes the goal of efficient modification of waste Mg alloy,high-quality utilization of seawater,and low-cost and controllable hydrogen production process.展开更多
Extracellular membrane proteins are crucial for mediating cell attachment,recognition,and signal transduction in the testicular microenvironment,particularly germline stem cells.Cadherin 18(CDH18),a type Ⅱ classical ...Extracellular membrane proteins are crucial for mediating cell attachment,recognition,and signal transduction in the testicular microenvironment,particularly germline stem cells.Cadherin 18(CDH18),a type Ⅱ classical cadherin,is primarily expressed in the nervous and reproductive systems.Here,we investigated the expression of CDH18in neonatal porcine prospermatogonia(ProSGs)and murine spermatogonial stem cells(SSCs).Disruption of CDH18 expression did not adversely affect cell morphology,proliferation,self-renewal,or differentiation in cultured porcine ProSGs,but enhanced cell adhesion and prolonged cell maintenance.Transcriptomic analysis indicated that the down-regulation of CDH18 in ProSGs significantly up-regulated genes and signaling pathways associated with cell adhesion.To further elucidate the function of CDH18 in germ cells,Cdh18 knockout mice were generated,which exhibited normal testicular morphology,histology,andspermatogenesis.Transcriptomic analysis showed increased expression of genes associated with adhesion,consistent with the observations in porcine ProSGs.The interaction of CDH18withβ-catenin and JAK2 in both porcine ProSGs and murine SSCs suggested an inhibitory effect on the canonical Wnt and JAK-STAT signaling pathways during CDH18 deficiency.Collectively,these findings highlight the crucial role of CDH18 in regulating cell adhesion in porcine ProSGs and mouse SSCs.Understanding this regulatory mechanism provides significant insights into the testicular niche.展开更多
Traditional topology optimization methods often suffer from the“dimension curse”problem,wherein the com-putation time increases exponentially with the degrees of freedom in the background grid.Overcoming this challe...Traditional topology optimization methods often suffer from the“dimension curse”problem,wherein the com-putation time increases exponentially with the degrees of freedom in the background grid.Overcoming this challenge,we introduce a real-time topology optimization approach leveraging Conditional Generative Adversarial Networks with Gradient Penalty(CGAN-GP).This innovative method allows for nearly instantaneous prediction of optimized structures.Given a specific boundary condition,the network can produce a unique optimized structure in a one-to-one manner.The process begins by establishing a dataset using simulation data generated through the Solid Isotropic Material with Penalization(SIMP)method.Subsequently,we design a conditional generative adversarial network and train it to generate optimized structures.To further enhance the quality of the optimized structures produced by CGAN-GP,we incorporate Pix2pixGAN.This augmentation results in sharper topologies,yielding structures with enhanced clarity,de-blurring,and edge smoothing.Our proposed method yields a significant reduction in computational time when compared to traditional topology optimization algorithms,all while maintaining an impressive accuracy rate of up to 85%,as demonstrated through numerical examples.展开更多
Purpose-To optimize train operations,dispatchers currently rely on experience for quick adjustments when delays occur.However,delay predictions often involve imprecise shifts based on known delay times.Real-time and a...Purpose-To optimize train operations,dispatchers currently rely on experience for quick adjustments when delays occur.However,delay predictions often involve imprecise shifts based on known delay times.Real-time and accurate train delay predictions,facilitated by data-driven neural network models,can significantly reduce dispatcher stress and improve adjustment plans.Leveraging current train operation data,these models enable swift and precise predictions,addressing challenges posed by train delays in high-speed rail networks during unforeseen events.Design/methodology/approach-This paper proposes CBLA-net,a neural network architecture for predicting late arrival times.It combines CNN,Bi-LSTM,and attention mechanisms to extract features,handle time series data,and enhance information utilization.Trained on operational data from the Beijing-Tianjin line,it predicts the late arrival time of a target train at the next station using multidimensional input data from the target and preceding trains.Findings-This study evaluates our model’s predictive performance using two data approaches:one considering full data and another focusing only on late arrivals.Results show precise and rapid predictions.Training with full data achieves aMAEof approximately 0.54 minutes and a RMSEof 0.65 minutes,surpassing the model trained solely on delay data(MAE:is about 1.02 min,RMSE:is about 1.52 min).Despite superior overall performance with full data,the model excels at predicting delays exceeding 15 minutes when trained exclusively on late arrivals.For enhanced adaptability to real-world train operations,training with full data is recommended.Originality/value-This paper introduces a novel neural network model,CBLA-net,for predicting train delay times.It innovatively compares and analyzes the model’s performance using both full data and delay data formats.Additionally,the evaluation of the network’s predictive capabilities considers different scenarios,providing a comprehensive demonstration of the model’s predictive performance.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 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supported by Rosa roxburghii industry development program of Guizhou Province,China(QCN2019-261)the National Natural Science Foundation of China(31260379)the National Natural Science Foundation of China(31960485).
文摘This study mainly investigated the regulatory effect of Rosa roxburghii Tratt fruit juice fermented by Lacticaseibacillus paracasei SR10-1(LAB-RRTJ)on modulating gut microbiota in dextran sulfate sodium(DSS)-induced ulcerative colitis in mice.Compared to control group,DSS induction decreased body weight of mice,indexes of Shannon,Simpson,Chao1 and Faith_pd,and increased disease activity index(DAI)and levels of interleukin 1β(IL-1β),IL-6,tumor necrosis factorα(TNF-α)and interferon-γ(IFN-γ);And this induction also led to an increase in Proteobacteria,Verrucomicrobia and Actinobacteria at phylum level,harmful bacterial species richness at genus level,and relative richness of S.sciuri,Desulfovibrio C21_c20,R.gnavus and Akkermansia muciniphila at species level,and a decrease in Firmicutes at phylum level and relative richness of B.acidifaciens in mice.LAB-RRTJ increased body weight of mice with DSS induced ulcerative colitis(UC)and indexes of Shannon,Simpson,Chao1 and Faith_pd,reduced DAI and the content of four infl ammatory factors and improved gut microbiota imbalance in DSS induced UC mice.Besides,the number of operational taxonomic units(OTUs)increased,α-diversity andβ-diversity were restored and similar to those in mice in the control group after LAB-RRTJ treatment.Compared with the positive drug treatment group,LAB-RRTJ has a better effect on regulating gut microbiota diversity in colitis mice.Correlation analysis showed that infl ammatory factors were positively correlated with harmful bacteria and negatively correlated with beneficial bacteria which commonly found in some colitis mice.Taken together,our study demonstrated that LAB-RRTJ could alleviate DSS-induced colitis in mice through the modulation of infl ammatory cytokines and gut microbiota composition.
基金supported by the National Natural Science Foundation of China(22378277)the 111 project(B17030)the Basal Research Fund of the Central University(2016SCU04B06).
文摘High-efficient production of 5-hydroxymethylfurfural(HMF),a“sleeping giant”in sustainable chemistry,from cellulose depends significantly on the effective separation of cellulose from lignocellulosic biomass.Herein,we report the fractional separation of wheat straw cellulose(WSC)from wheat straw under solvothermal conditions using a mixed solvent of γ-valerolactone(GVL)and H_(2)O as the separating solvent,wherein the impacts of fractional separation parameters(solvent composition,temperature,and time)on removals of lignin and hemicellulose as well as purity and recovery of cellulose were studied by a Box-Behnken Design of response surface method.The optimization of the solvothermal parameters enabled an optimal fractional separation condition(V_(GVL):~60.0%,T:205℃,t:~1.7 h)that led to a higher purity(89.4%)and recovery(86.7%)of cellulose in WSC.A further correlation of the removals of lignin and hemicellulose as well as purity and recovery of cellulose with the yield of HMF excluded an independent influence of the above factors.Instead,a comprehensive contribution of high fractional separation efficiency(defined as the product of cellulose purity and recovery)and low crystallinity of WSC was found to improve the HMF yield.However,the heat-and freeze-dryings of WSC after the solvothermal separation were found to lower the HMF molar yield because it re-improved the crystallinity of WSC.A high HMF molar yield of 58.6%was achieved after reacting wet-WSC in a mixed solvent of 1,4-dioxane and H_(2)O at 180℃for 20 min,which was 1.5 fold higher than that from microcrystalline cellulose.This work highlights the importance of enhancing the fractional separation efficiency of cellulose from lignocellulosic biomass while avoiding the drying process for future HMF biorefinery.
基金supported by the Major Program of National Natural Science Foundation of China(No.52293372).
文摘High-density carbon/carbon(C/C)composite plays a critical role in the aerospace industry owing to excellent mechanical properties and resistance to ablation.However,traditional manufacturing relies on pitch precursor and hot isostatic pressure impregnation and carbonization(HIPIC)technology,which is time-consuming and expensive.In this study,we report an innovative method utilizing polyarylacetylene(PAA)resin and ultra-high pressure impregnation and carbonization(UHPIC)technology.The extremely high char yield of PAA resin(85 wt.%)and high isotropic pressure of UHPIC(over 200 MPa)promote the densification of the composite.As a result,we achieve a high-density(1.90 g/cm^(3))C/C composite with a high degree of graphitization(81%).This composite exhibits impressive properties,including flexural strength of 146 MPa,compressive strength of 187 MPa,and thermal conductivity of 147 W/(m K).When exposed to oxyacetylene flame at 3000 K for 100 s,it displays minimal linear ablation,with a rate of 1.27×10^(-2)mm/s.This study demonstrates the exceptional graphitizable characteristic of PAA resin,setting it apart from conventional resins.Our time-saving and cost-effective approach holds significant promise for aerospace applications,particularly in harsh aerodynamic heating environments.
基金supported by Yulin Science and Technology Bureau (Grant No 2023-CXY-202)Scientific Research Program Funded by Shaanxi Provincial Education Department (Grant No 23JP008)Key Research and Development Projects of Shaanxi Province (Grant No 2024GXYBXM-213) and (Grant No 52102109)
文摘In response to global carbon neutrality targets,there is an urgent need for large-scale,clean hydrogen production technologies to supplant fossil fuels and underpin the establishment of a‘hydrogen economy’.The prospect of large-scale on-site green hydrolysis of Mg-based materials for hydrogen production has attracted wide attention.Aiming at the problems of easy formation of inert oxide layer on its surface and the production of Mg(OH)_(2) to hinder the hydrolysis process,it is urgent to explore efficient,low-cost and green modification strategies.In this work,the green modification strategy for hydrolyzing hydrogen production of Mg-based materials was summarized,and the fast initial kinetics and high hydrogen production rate could be achieved by adjusting hydrolysis medium conditions and modifying Mg-based material.The significance of hydrolytic hydrogen production technology and device development for the realization of Mg-based hydrolytic hydrogen production was evaluated.Meanwhile,this work looks forward to the future direction of hydrogen production modification by hydrolysis of Mg-based alloy,and gradually optimizes the hydrolysis performance of industrial multi-component waste Mg alloy under the premise of green hydrogen production,and proposes the goal of efficient modification of waste Mg alloy,high-quality utilization of seawater,and low-cost and controllable hydrogen production process.
基金supported by the Jiangsu Seed Industry Revitalization Project(JBGS[2021]024)Fundamental Research Funds for the Central Universities(KYT2023002)+2 种基金Jiangsu Province Capability Improvement Project through Science,TechnologyEducation Jiangsu Provincial Medical Key Discipline(ZDXK202211)Shandong Province Natural Science Foundation(ZR2020MC074)
文摘Extracellular membrane proteins are crucial for mediating cell attachment,recognition,and signal transduction in the testicular microenvironment,particularly germline stem cells.Cadherin 18(CDH18),a type Ⅱ classical cadherin,is primarily expressed in the nervous and reproductive systems.Here,we investigated the expression of CDH18in neonatal porcine prospermatogonia(ProSGs)and murine spermatogonial stem cells(SSCs).Disruption of CDH18 expression did not adversely affect cell morphology,proliferation,self-renewal,or differentiation in cultured porcine ProSGs,but enhanced cell adhesion and prolonged cell maintenance.Transcriptomic analysis indicated that the down-regulation of CDH18 in ProSGs significantly up-regulated genes and signaling pathways associated with cell adhesion.To further elucidate the function of CDH18 in germ cells,Cdh18 knockout mice were generated,which exhibited normal testicular morphology,histology,andspermatogenesis.Transcriptomic analysis showed increased expression of genes associated with adhesion,consistent with the observations in porcine ProSGs.The interaction of CDH18withβ-catenin and JAK2 in both porcine ProSGs and murine SSCs suggested an inhibitory effect on the canonical Wnt and JAK-STAT signaling pathways during CDH18 deficiency.Collectively,these findings highlight the crucial role of CDH18 in regulating cell adhesion in porcine ProSGs and mouse SSCs.Understanding this regulatory mechanism provides significant insights into the testicular niche.
基金supported by the National Key Research and Development Projects (Grant Nos.2021YFB3300601,2021YFB3300603,2021YFB3300604)Fundamental Research Funds for the Central Universities (No.DUT22QN241).
文摘Traditional topology optimization methods often suffer from the“dimension curse”problem,wherein the com-putation time increases exponentially with the degrees of freedom in the background grid.Overcoming this challenge,we introduce a real-time topology optimization approach leveraging Conditional Generative Adversarial Networks with Gradient Penalty(CGAN-GP).This innovative method allows for nearly instantaneous prediction of optimized structures.Given a specific boundary condition,the network can produce a unique optimized structure in a one-to-one manner.The process begins by establishing a dataset using simulation data generated through the Solid Isotropic Material with Penalization(SIMP)method.Subsequently,we design a conditional generative adversarial network and train it to generate optimized structures.To further enhance the quality of the optimized structures produced by CGAN-GP,we incorporate Pix2pixGAN.This augmentation results in sharper topologies,yielding structures with enhanced clarity,de-blurring,and edge smoothing.Our proposed method yields a significant reduction in computational time when compared to traditional topology optimization algorithms,all while maintaining an impressive accuracy rate of up to 85%,as demonstrated through numerical examples.
基金supported in part by the National Natural Science Foundation of China under Grant 62203468in part by the Technological Research and Development Program of China State Railway Group Co.,Ltd.under Grant Q2023X011+1 种基金in part by the Young Elite Scientist Sponsorship Program by China Association for Science and Technology(CAST)under Grant 2022QNRC001in part by the Youth Talent Program Supported by China Railway Society,and in part by the Research Program of China Academy of Railway Sciences Corporation Limited under Grant 2023YJ112.
文摘Purpose-To optimize train operations,dispatchers currently rely on experience for quick adjustments when delays occur.However,delay predictions often involve imprecise shifts based on known delay times.Real-time and accurate train delay predictions,facilitated by data-driven neural network models,can significantly reduce dispatcher stress and improve adjustment plans.Leveraging current train operation data,these models enable swift and precise predictions,addressing challenges posed by train delays in high-speed rail networks during unforeseen events.Design/methodology/approach-This paper proposes CBLA-net,a neural network architecture for predicting late arrival times.It combines CNN,Bi-LSTM,and attention mechanisms to extract features,handle time series data,and enhance information utilization.Trained on operational data from the Beijing-Tianjin line,it predicts the late arrival time of a target train at the next station using multidimensional input data from the target and preceding trains.Findings-This study evaluates our model’s predictive performance using two data approaches:one considering full data and another focusing only on late arrivals.Results show precise and rapid predictions.Training with full data achieves aMAEof approximately 0.54 minutes and a RMSEof 0.65 minutes,surpassing the model trained solely on delay data(MAE:is about 1.02 min,RMSE:is about 1.52 min).Despite superior overall performance with full data,the model excels at predicting delays exceeding 15 minutes when trained exclusively on late arrivals.For enhanced adaptability to real-world train operations,training with full data is recommended.Originality/value-This paper introduces a novel neural network model,CBLA-net,for predicting train delay times.It innovatively compares and analyzes the model’s performance using both full data and delay data formats.Additionally,the evaluation of the network’s predictive capabilities considers different scenarios,providing a comprehensive demonstration of the model’s predictive performance.
