In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still face...In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still faced with defects such as low intrinsic ionic conductivity,a narrow electrochemical window,and poor thermal stability.A crosslinking and fluorination molecular design strategy toward PDOL is proposed to tackle the issues above.The amorphous crosslinked structure effectively improves ionic conductivity by inhibiting long-chain crystallization.Especially,the antioxidant–CF_(3)groups,stable crosslinked structure,and reduced terminal hydroxyl groups significantly enhance the electrochemical oxidation stability with a superb high-voltage window of 4.7 V.In addition,the designed electrolyte also exhibits obviously improved thermal stability with no deformation at 120°C for 5 min.Furthermore,the semi-solid NCM811||Li batteries exhibit a favourable capacity retention of 88.8%after 150 cycles at 0.5 C.Even assembled with NCM622 cathode working at 4.5 V,the semi-solid batteries can still show a satisfactory capacity retention of 85.3%after 100 cycles at 0.5 C.Also,a 0.1 Ah NCM811||Li pouch cell with active materials loading of 9 mg/cm2 demonstrates satisfactory cycling stability and working ability,which shows promising practical application prospects.展开更多
Zinc(Zn)deficiency is a global health issue,exacerbated by low Zn concentration and poor bioavailability in rice,primarily due to phytic acid(PA)interference.In this study,four doubled haploid(DH)progenies(DH1,DH11,DH...Zinc(Zn)deficiency is a global health issue,exacerbated by low Zn concentration and poor bioavailability in rice,primarily due to phytic acid(PA)interference.In this study,four doubled haploid(DH)progenies(DH1,DH11,DH18,and DH29)with distinct Zn and PA profiles were used to evaluate the effects of varying degrees of milling(DOM)on Zn bioavailability.Results showed DOM followed a double-exponential decay pattern(R^(2)>0.99)with milling time,varying among the four DH lines under identical milling conditions.As DOM increased,Zn,PA,and phosphorus(P)concentrations decreased progressively.展开更多
Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded...Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded organic frameworks(HOFs)have promising application potential for embedding enzymes.In fact,no metal involvement is required,and HOFs exhibit superior biocompatibility,and free access to substrates in mesoporous channels.Herein,a facile in situ growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF.The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions(aqueous phase and ambient temperature)with a controllable embedding rate.The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%.This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81%of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme.Based on this controllably synthesized bio-catalytic material and a common lipase,we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid(R-3-HBA).展开更多
Intelligent manufacturing(IM),a driving force behind the fourth industrial revolution,is reshaping the manufacturing sector by enhancing productivity,efficiency,and sustainability.Despite the rapid technological advan...Intelligent manufacturing(IM),a driving force behind the fourth industrial revolution,is reshaping the manufacturing sector by enhancing productivity,efficiency,and sustainability.Despite the rapid technological advancements in IM,comprehensive bibliometric reviews remain limited.This article systematically reviews the latest research in IM,addressing emerging hotspots,key technologies,and their applications across the entire product manufacturing cycle.Bibliometric analysis is employed to identify research trends visualize publication volume,collaboration patterns,research domains,co-citations,and emerging areas of interest.The article then examines key technologies supporting IM,including sensors,the Internet of Things(IoT),big data analytics,cloud computing,artificial intelligence(AI),digital twins,and virtual reality(VR)/augmented reality(AR).Furthermore,it explores the application of these technologies throughout the manufacturing cycle-from intelligent reliability design,material transportation and tracking,to intelligent planning and scheduling,machining and fabrication,monitoring and maintenance,quality inspection and control,warehousing and management,and sustainable green manufacturing—through specific case studies.Lastly,the article discusses future research directions,highlighting the increasing global market and the need for enhanced interdisciplinary collaboration,technological integration,computing power upgrades,and attention to security and privacy in IM.This study provides valuable insights for scholars and serves as a guide for future research and strategic investment decisions,offering a comprehensive view of the IM field.展开更多
With the increasing consumption of non renewable resources such as oil,the traditional polymer manufacturing industry that relies on fossil resources is facing unprecedented challenges.The design,synthesis,and recycli...With the increasing consumption of non renewable resources such as oil,the traditional polymer manufacturing industry that relies on fossil resources is facing unprecedented challenges.The design,synthesis,and recycling of renewable and environmentally friendly bio-based polymers as alternatives to petroleum based polymers have become hot topics in research and industrial fields.Biomass has been used as a raw material to design and synthesize closed-loop recyclable polymers,which is of great significance in addressing the waste of resources and negative impact on the environment in the traditional polymer preparation process.This review summarized recent advances in the design,synthesis,and properties of closed-loop recyclable bio-based polymers,focusing on the sustainability and recyclability of bio-based materials,followed by a brief discussion of the potential applications of closed-loop recyclable bio-based polymers in emerging applications such as 3D printing and friction electric nanogenerators.In addition,perspectives and recommendations for future research on closedloop recyclable bio-based polymers were presented.展开更多
Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains...Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains a confusing topic.Here we develop a hydrogen-bond-oriented interfacial super-assembly strategy to custom-tailor nanosheet-intertwined spherical carbon superstructures(SCSs)for Zn-ion storage with double-high capacitive activity and durability.Tetrachlorobenzoquinone(H-bond acceptor)and dimethylbenzidine(H-bond donator)can interact to form organic nanosheet modules,which are sequentially assembled,orientally compacted and densified into well-orchestrated superstructures through multiple H-bonds(N-H···O).Featured with rich surface-active heterodiatomic motifs,more exposed nanoporous channels,and successive charge migration paths,SCSs cathode promises high accessibility of built-in zincophilic sites and rapid ion diffusion with low energy barriers(3.3Ωs-0.5).Consequently,the assembled Zn||SCSs capacitor harvests all-round improvement in Zn-ion storage metrics,including high energy density(166 Wh kg-1),high-rate performance(172 m Ah g^(-1)at 20 A g^(-1)),and long-lasting cycling lifespan(95.5%capacity retention after 500,000 cycles).An opposite chargecarrier storage mechanism is rationalized for SCSs cathode to maximize spatial capacitive charge storage,involving high-kinetics physical Zn^(2+)/CF_(3)SO_(3)-adsorption and chemical Zn^(2+)redox with carbonyl/pyridine groups.This work gives insights into H-bond-guided interfacial superassembly design of superstructural carbons toward advanced energy storage.展开更多
Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-...Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-linked-immunoassay(ELISA)method was developed to determine 3-NT in modified model protein(bovine serum albumin,BSA)and ambient aerosol samples.The nitration degrees(NDs)of BSA in the exposure experiments with different durations were detected by both the ELISA and spectrophotometric methods(i.e.,ND_(ELISA) and ND_(SEC-PDA)),which show good coincidence.The kinetic investigation by both ΔND_(ELISA) and ΔND_(SEC-PDA) in the exposure experiments shows that the rate coefficients(k)of the pseudo-first-order kinetic rate reactions of protein nitration were comparable.These results indicate that direct detection of 3-NT by the ELISA method can be applied for laboratory exposure samples analysis for kinetic studies.Based on the selective detection of 3-NT,ND_(ELISA) provides a promising measure for the assessment of ND in model proteins.3-NT was alsomeasured in PM_(2.5) samples in summer in Guangzhou,southern China,ranging from 10.1 to 404 pg/m^(3),providing clear evidence of protein nitration in ambient aerosols.We further proposed that 3-NT/protein can be used as a proxy to evaluate protein nitration in ambient aerosols.A significant correlationwas observed between 3-NT/protein and O_(3),confirming the crucial role of O_(3) in protein nitration.Our results show that the direct detection of 3-NT by the ELISA method can be more widely applied in the laboratory and field-based studies for understanding the mechanisms of protein nitration.展开更多
The traditional nanozymes-based ratiometric fluorescence sensing platforms usually necessitate the supplementary addition of fluorescent probes,therefore greatly restricting its convenient and broad application.In thi...The traditional nanozymes-based ratiometric fluorescence sensing platforms usually necessitate the supplementary addition of fluorescent probes,therefore greatly restricting its convenient and broad application.In this study,a highly sensitive and selective ratiometric fluorescence platform for alkaline phosphatase(ALP)detection was established,only employing Prussian blue(PB)nanozymes and a commercially available chromogen of o-phenylenediamine(OPD).PB nanozymes with remarkable peroxidaselike(POD-like)activity can effectively catalyze OPD chromogen to yield 2,3-diaminophenazine(OPDox)with an intense yellow fluorescence at 573 nm emission peak.Target ALP can facilitate ascorbic acid 2-phosphate(AAP)dephosphorylation to generate phosphate and ascorbic acid(AA).Significantly,both these two resultant hydrolysis products could effectively decrease the OPDox generation via a dualpath based inhibition on the PB nanozymes POD-like activity.On the other hand,the generated dehydroascorbic acid(DHAA)from AA oxidation would exclusively react with OPD chromogen to yield3-(dihydroxyethyl)furo[3,4-b]quinoxaline-1-one(DFQ)with a strong blue fluorescent signal at 434nm,which further providing a significant enhancement on the sensing selectivity of ALP detection.As a result,an increased yellow fluorescence of OPDox and decreased blue fluorescence of DFQ could be clearly observed with different ALP addition.A robust linear relationship between the fluorescence ratio of F_(434)/F_(573)and ALP activity ranging from 0.25U/L to 6U/L was obtained,with a low detection limit of 0.112 U/L.This proposed method demonstrates high sensitivity,excellent selectivity,cost-effectiveness,and operational simplicity,yet enabling an effective detection of ALP levels in human serum.展开更多
In this work,we proposed a strategy for the hydrolysis of native corn starch after the treatment of corn starch in an ionic liquid aqueous solution,and it is an awfully“green”and simple means to obtain starch with l...In this work,we proposed a strategy for the hydrolysis of native corn starch after the treatment of corn starch in an ionic liquid aqueous solution,and it is an awfully“green”and simple means to obtain starch with low molecular weight and amorphous state.X-ray diffraction results revealed that the natural starch crystalline region was largely disrupted by ionic liquid owing to the broken intermolecular and intramolecular hydrogen bonds.After hydrolysis,the morphology of starch changed from particles of native corn starch into little pieces,and their molecular weight could be effectively regulated during the hydrolysis process,and also the hydrolyzed starch samples exhibited decreased thermal stability with the extension of hydrolysis time.This work would counsel as a powerful tool for the development of native starch in realistic applications.展开更多
A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quino...A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quinonemethides and their stereoisomers,impact the reactivity of cyclopropanation.The configurations at C9,C8,and C14 for all four pentacyclic diastereoisomers involved in the diastereoisomeric mixture were determined through a combination of suitable chemical derivatization and multiple NMR spectroscopic analyses.Based on the defined configuration,the 3D structures of these diastereoisomers were optimized by density functional theory(DFT)calculation.These investigations provide reasonable supports,mainly from the steric considerations,for understanding why different diastereoisomers exhibit markedly different reactivity,as well as regio-and stereo-selectivity for cyclopropanation.In addition,the mechanism for the construction of the spiroannulated 6-6-6-5-5 pentacyclic scaffold via intramolecular Michael/aldol cascade was also investigated by deuterium labeling experiments.展开更多
Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during fr...Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during frozen storage.Product indicators including pH,colour,thiobarbituric acid reactive substances(TBARS),total volatile basic nitrogen(TVB-N),texture,electronic nose(E-nose)response,and water-holding capacity(thawing and cooking losses)were determined.The results indicated that as storage time increased,water retention in Sichuan sausages with different moisture contents decreased,while the degree of protein and lipid oxidation increased.This led to an increase in pH value,a colour shift from red-bright to grey-brown,and a deterioration in palatability.Among the samples,sausages with 50% moisture content exhibited the lowest thawing and cooking losses,indicating superior water-holding capacity.After 8 weeks of storage,TBARS and TVB-N values for the 50% moisture group were 19.5%and 2.5%lower,respectively,than those of the 40%and 45%moisture groups,indicating a reduced degree of oxidation.Furthermore,Sichuan sausage with 50%moisture content demonstrated an appropriate pH and colour difference,along with excellent texture and flavour,as evidenced by its higher toughness and satisfactory hardness.In conclusion,Sichuan sausage with 50% moisture content demonstrated the highest overall quality under frozen storage conditions.展开更多
Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is c...Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is crucial for the confirmation of absolute configurations.Ignoring critical parameters will lead to false structure,which may confuse the total synthesis and drug development.Herein,the configurations of seven heterogeneous Pallavicinia diterpenoids(PDs) isolated from Pallavicinia liverworts are revised using a combination of single-crystal X-ray diffraction and electronic circular dichroism(ECD) calculations.Meanwhile,identification of five unprecedented PD heterodimers PD-dimers A-E(18-22) along with eleven previously undescribed PDs(5-9,13-17,23) obtained by the reinvestigation of the Chinese liverwort Pallavicinia subciliata have resulted in corrections and support the revised conclusions.展开更多
User identity linkage(UIL)across online social networks seeks to match accounts belonging to the same real-world individual.This cross-platformmapping enables accurate user modeling but also raises serious privacy ris...User identity linkage(UIL)across online social networks seeks to match accounts belonging to the same real-world individual.This cross-platformmapping enables accurate user modeling but also raises serious privacy risks.Over the past decade,the research community has developed a wide range of UIL methods,from structural embeddings tomultimodal fusion architectures.However,corresponding adversarial and defensive approaches remain fragmented and comparatively understudied.In this survey,we provide a unified overview of both mapping and antimappingmethods for UIL.We categorize representativemappingmodels by learning paradigmand datamodality,and systematically compare them with emerging countermeasures including adversarial injection,structural perturbation,and identity obfuscation.To bridge these two threads,we introduce amodality-oriented taxonomy and a formal gametheoretic framing that casts cross-network mapping as a contest between mappers and anti-mappers.This framing allows us to construct a cross-modality dependency matrix,which reveals structural information as themost contested signal,identifies node injection as the most robust defensive strategy,and points to multimodal integration as a promising direction.Our survey underscores the need for balanced,privacy-preserving identity inference and provides a foundation for future research on the adversarial dynamics of social identity mapping and defense.展开更多
Early fault detection for spiral bevel gears is crucial to ensure normal operation and prevent accidents.The harmonic components,excited by the time-varying mesh stiffness,always appear in measured vibration signal.Ho...Early fault detection for spiral bevel gears is crucial to ensure normal operation and prevent accidents.The harmonic components,excited by the time-varying mesh stiffness,always appear in measured vibration signal.How to extract the periodical impulses that indicate gear localized fault buried in the intensive noise and interfered by harmonics is a challenging task.In this paper,a novel Periodical Sparse-Assisted Decoupling(PSAD)method is proposed as an optimization problem to extract fault feature from noisy vibration signal.The PSAD method decouples the impulsive fault feature and harmonic components based on the sparse representation method.The sparsity within and across groups property and the periodicity of the fault feature are incorporated into the regularizer as the prior information.The nonconvex penalty is employed to highlight the sparsity of fault features.Meanwhile,the weight factor based on2norm of each group is constructed to strengthen the amplitude of fault feature.An iterative algorithm with Majorization-Minimization(MM)is derived to solve the optimization problem.Simulation study and experimental analysis confirm the performance of the proposed PSAD method in extracting and enhancing defect impulses from noisy signal.The suggested method surpasses other comparative methods in extracting and enhancing fault features.展开更多
Photoreforming poly(lactic acid)(PLA)plastics into pyruvic acid(PA)coupled with hydrogen evolution is of great significance for sustainable development.However,a significant challenge lies inα-OH bond cleaving of lac...Photoreforming poly(lactic acid)(PLA)plastics into pyruvic acid(PA)coupled with hydrogen evolution is of great significance for sustainable development.However,a significant challenge lies inα-OH bond cleaving of lactic acid(LA).Herein,CdS/Bi_(4)Ti_(3)O_(12)composite is fabricated,bridged by Bi−S bonds,through in-situ growth of CdS nanoparticles on Bi_(4)Ti_(3)O_(12)nanoflowers for the successive removal of hydrogen fromα-C in LA.In-situ X-ray photoelectron spectroscopy confirms the S-scheme carriers transfer route and interfacial Bi−S bond in CdS/Bi_(4)Ti_(3)O_(12).Consequently,the photo-electrons and holes with extended lifetimes and strong redox potential accumulate in the CdS conduction band and Bi_(4)Ti_(3)O_(12)valence band,respectively,as evidenced by in-situ electron spin resonance and time-resolved photoluminescence.This facilitates the generation of·OH radicals,which further participate in the successive dehydrogenation reaction of LA.Consequently,the photoreforming efficiencies of converting PLA into PA and H_(2)by CdS/Bi_(4)Ti_(3)O_(12)are 1.7 and 3.16 mmol g^(-1)h^(-1),which are respectively 2.8 and 22 times higher than that by pristine Bi_(4)Ti_(3)O_(12).The present work provides a new approach for designing S-scheme to achieve hydrogen production and value-added conversion of plastics.展开更多
Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in co...Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in complex mountainous riverine reservoirs remain inadequately understood.We employed high-throughput sequencing of 16S and 18S ribosomal RNA genes,along with multivariate statistical methods to systematically investigate prokaryotic and eukaryotic microorganisms in the riverine Zhaoshandu Reservoir,Wenzhou,Zhejiang,East China.Results show significant temporal heterogeneity in both prokaryotic and eukaryotic microbial communities,with eukaryotic microbes showing more pronounced temporal variation.Canonical correspondence analysis revealed that rainfall and water temperature were the key drivers shaping microbial communities.Additionally,eukaryotic microorganisms exhibited a more pronounced response to rainfall and water temperature compared to prokaryotes.Modified stochasticity ratio model indicated that deterministic processes predominantly governed microbial community assembly,with stronger deterministic processes in eukaryotic compared to prokaryotic microorganisms.Rainfall has significantly altered water quality,notably increasing phosphorus concentration in the water column.Total phosphorus and total nitrogen showed significant correlations with the niche breadth of prokaryotic and eukaryotic microorganisms,and phosphorus nutrients served as keystones and playing indispensable roles in their co-occurrence networks.A structural equation model confirmed the notable impacts of rainfall and water temperature on microbial community diversity,further revealing that rainfall indirectly influenced the niche breadth and co-occurrence relationships of microbial communities by altering phosphorus concentrations.The findings underscore the influence of rainfall and water temperature on microbial distribution,highlighting the sensitivity of riverine reservoir ecosystems to climate change.展开更多
Reactive compatibilization has been widely applied to enhance the compatibility of polymer blends,thereby improving their mechanical properties.However,it generally reduces the chain mobility and regularity,often lead...Reactive compatibilization has been widely applied to enhance the compatibility of polymer blends,thereby improving their mechanical properties.However,it generally reduces the chain mobility and regularity,often leading to slower polymer crystallization.Here,we demonstrate that reactive compatibilization in poly(lactic acid)/poly(butylene adipate-co-terephthalate)(PLA/PBAT)blends unexpectedly promotes PLA matrix crystallization during injection molding,in contrast to the retarded kinetics observed in differential scanning calorimetry isothermal crystallization studies.The phase morphology,rheological behavior,and crystalline structure were systematically analyzed to elucidate markedly different crystallization kinetics under static and shear fields.The potential mechanism underlying crystallization enhancement is attributed to PBAT domain refinement and viscosity increase induced by reactive compatibilization,which,under shear flow,create favorable conditions for crystallization by enhancing PBAT fibril nucleation and retarding the relaxation of oriented PLA chains.This study offers new perspectives on the effect of reactive compatibilization on the polymer crystallization behavior.展开更多
Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China ...Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China in winter and spring of 2021.The results show that the average concentration of PM_(2.5) decreased by 47%from winter to spring,while volume-normalized and mass-normalized OP(i.e.,OP_(v) and OP_(m))increased by 6%and 69%,respectively.It suggests that the decline of PM_(2.5) may not necessarily decrease the health risks and the intrinsic toxicity of PM_(2.5).Variations of OP_(v) and OP_(m) among different periods were related to the different source contributions and environmental conditions.The positive matrix factorization model was used to identify the major sources of OP_(v).OP_(v) was mainly contributed by biomass burning/industrial emissions(29%),soil/road dust(20%),secondary sulfate(14%),and coal combustion(13%)in winter.Different major sources were resolved to be secondary sulfate(36%),biological sources(21%),and marine vessels(20%)in spring,presenting the substantial contribution of biological sources.The analysis shows strong associations between OP_(v) and both live and dead bacteria,further confirming the important contribution of bioaerosols to the enhancement of OP.This study highlights the importance of understanding OP in ambient PM_(2.5) in terms of public health impact and provides a new insight into the biological contribution to OP.展开更多
Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face wit...Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face with their intrinsic limitations including metabolic instability and low membrane permeability,the strategies for synthesizing unnatural amino acids and peptides are explored.Among the methods for modifying amino acids and peptides,chemo-and site-selective approaches are preferred because of the ability to fine-tuning structural features.Recently,transition metal-catalyzed C–H activation has been employed for the functionalization of amino acids and peptides.Through domino C–H activation/annulation,a series of structurally complex and diverse amino acids and peptides is constructed.This review highlights recent advances in the synthesis of unnatural amino acids and peptides via transition metal-catalyzed C–H activation/annulation.展开更多
To inhibit the interfacial(displacement)reaction between Hf and Al elements in the DZ125 superalloy and the Al_(2)O_(3) and SiO_(2) in the Al_(2)O_(3)-based ceramic shell,rare-earth oxides(La_(2)O_(3) and Y_(2)O_(3))w...To inhibit the interfacial(displacement)reaction between Hf and Al elements in the DZ125 superalloy and the Al_(2)O_(3) and SiO_(2) in the Al_(2)O_(3)-based ceramic shell,rare-earth oxides(La_(2)O_(3) and Y_(2)O_(3))were used as dopants into the shell.The effects of dopant types and contents(2 wt%,5 wt%and 8 wt%)on the wettability and interfacial reaction were investigated using the sessile-drop experiment,and the reaction products were analyzed by X-ray diffraction(XRD),a scanning electron microscope(SEM),an electron probe microanalyzer(EPMA)and X-ray photoelectron spectroscopy(XPS),to clarify the mechanism of dopants in the interracial reaction.The results show that increasing the Y_(2)O_(3) doping content(2 wt%-8 wt%)reduces the surface porosity from 22.39%to 13.43%,and decreases the surface roughness from 3.25 to 2.28μm,which enhances the packing density of the shell surface.In the sintering process(1223 K,2 h),both La_(2)O_(3) and Y_(2)O_(3) dopants react with SiO_(2),forming La_(2)Si_(2)O_(7) and Y_(2)SiO_(5) on the shell surface.During the interfacial reaction process(1823 K,40 min),La_(2)Si_(2)O_(7) decomposes and reacts with Al_(2)O_(3) and HfO_(2),resulting in the formation of SiO_(2)·HfO_(2)·La_(2)O_(3) and Al_(2)O_(3)·HfO_(2)·La_(2)O_(3) ternary composite oxides within the reaction products.At 8 wt%La_(2)O_(3) dopant content,the interfacial reaction is exacerbated,resulting in the uneven wettability.Y_(2)SiO_(5) further reacts with Al_(2)O_(3) and SiO_(2) to form SiO_(2)·Al_(2)O_(3)·Y_(2)O_(3) ternary composite oxides,while Y_(2)O_(3) combines with Al_(2)O_(3) to form Al_(5)Y_(3)O_(12)(VAG),which stabilizes the oxides within the shell and inhibits the interfacial reaction,and significantly improves the surface quality of the DZ125 superalloy.As the Y_(2)O_(3) dopant content increases(2 wt%-8 wt%),the wetting angle increases from 97.8°to 110.6°.展开更多
基金the financial support from the National Natural Science Foundation of China (No. 52072390)the National High-Level Talents Special Support Program (Leading Talent of Technological Innovation)+2 种基金the China Postdoctoral Science Foundation (No. 2023M743648)the Young Scientists Fund of the National Natural Science Foundation of China (No. 52302330)the support from the Shanghai Emperor of Cleaning Hi-Tech Co.,LTD
文摘In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still faced with defects such as low intrinsic ionic conductivity,a narrow electrochemical window,and poor thermal stability.A crosslinking and fluorination molecular design strategy toward PDOL is proposed to tackle the issues above.The amorphous crosslinked structure effectively improves ionic conductivity by inhibiting long-chain crystallization.Especially,the antioxidant–CF_(3)groups,stable crosslinked structure,and reduced terminal hydroxyl groups significantly enhance the electrochemical oxidation stability with a superb high-voltage window of 4.7 V.In addition,the designed electrolyte also exhibits obviously improved thermal stability with no deformation at 120°C for 5 min.Furthermore,the semi-solid NCM811||Li batteries exhibit a favourable capacity retention of 88.8%after 150 cycles at 0.5 C.Even assembled with NCM622 cathode working at 4.5 V,the semi-solid batteries can still show a satisfactory capacity retention of 85.3%after 100 cycles at 0.5 C.Also,a 0.1 Ah NCM811||Li pouch cell with active materials loading of 9 mg/cm2 demonstrates satisfactory cycling stability and working ability,which shows promising practical application prospects.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFD1200702)the Sanya Fanxing Technology Special Program,China(Grant No.2024KJFX023)the Shandong Provincial Key Research and Development Program,China(Grant No.2023LZGCQY018).
文摘Zinc(Zn)deficiency is a global health issue,exacerbated by low Zn concentration and poor bioavailability in rice,primarily due to phytic acid(PA)interference.In this study,four doubled haploid(DH)progenies(DH1,DH11,DH18,and DH29)with distinct Zn and PA profiles were used to evaluate the effects of varying degrees of milling(DOM)on Zn bioavailability.Results showed DOM followed a double-exponential decay pattern(R^(2)>0.99)with milling time,varying among the four DH lines under identical milling conditions.As DOM increased,Zn,PA,and phosphorus(P)concentrations decreased progressively.
基金supported by the National Key Research and Development Program of China(2019YFA0905100)the National Natural Science Foundation of China(21991102,22378227).
文摘Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded organic frameworks(HOFs)have promising application potential for embedding enzymes.In fact,no metal involvement is required,and HOFs exhibit superior biocompatibility,and free access to substrates in mesoporous channels.Herein,a facile in situ growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF.The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions(aqueous phase and ambient temperature)with a controllable embedding rate.The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%.This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81%of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme.Based on this controllably synthesized bio-catalytic material and a common lipase,we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid(R-3-HBA).
基金Supported by National Natural Science Foundation of China(Grant Nos.52375447,52305477 and 52105457)the Shandong Provincial Natural Science Foundation of China(Grant Nos.ZR2023QE057,ZR2024QE100 and ZR2024ME255)+2 种基金Qingdao Municipal Science and Technology Planning Park Cultivation Plan(Grant No.23-1-5-yqpy-17-qy)Shandong Provincial Science and Technology SMEs Innovation Capacity Improvement Project(Grant No.2022TSGC1115)the Special Fund of Taishan Scholars Project。
文摘Intelligent manufacturing(IM),a driving force behind the fourth industrial revolution,is reshaping the manufacturing sector by enhancing productivity,efficiency,and sustainability.Despite the rapid technological advancements in IM,comprehensive bibliometric reviews remain limited.This article systematically reviews the latest research in IM,addressing emerging hotspots,key technologies,and their applications across the entire product manufacturing cycle.Bibliometric analysis is employed to identify research trends visualize publication volume,collaboration patterns,research domains,co-citations,and emerging areas of interest.The article then examines key technologies supporting IM,including sensors,the Internet of Things(IoT),big data analytics,cloud computing,artificial intelligence(AI),digital twins,and virtual reality(VR)/augmented reality(AR).Furthermore,it explores the application of these technologies throughout the manufacturing cycle-from intelligent reliability design,material transportation and tracking,to intelligent planning and scheduling,machining and fabrication,monitoring and maintenance,quality inspection and control,warehousing and management,and sustainable green manufacturing—through specific case studies.Lastly,the article discusses future research directions,highlighting the increasing global market and the need for enhanced interdisciplinary collaboration,technological integration,computing power upgrades,and attention to security and privacy in IM.This study provides valuable insights for scholars and serves as a guide for future research and strategic investment decisions,offering a comprehensive view of the IM field.
基金Natural Science Foundation of China(Grant Nos.32471815 and 32401528)Natural Science Foundation of Jiangsu Province of China(Grant Nos.BK20241745 and BK20240294).
文摘With the increasing consumption of non renewable resources such as oil,the traditional polymer manufacturing industry that relies on fossil resources is facing unprecedented challenges.The design,synthesis,and recycling of renewable and environmentally friendly bio-based polymers as alternatives to petroleum based polymers have become hot topics in research and industrial fields.Biomass has been used as a raw material to design and synthesize closed-loop recyclable polymers,which is of great significance in addressing the waste of resources and negative impact on the environment in the traditional polymer preparation process.This review summarized recent advances in the design,synthesis,and properties of closed-loop recyclable bio-based polymers,focusing on the sustainability and recyclability of bio-based materials,followed by a brief discussion of the potential applications of closed-loop recyclable bio-based polymers in emerging applications such as 3D printing and friction electric nanogenerators.In addition,perspectives and recommendations for future research on closedloop recyclable bio-based polymers were presented.
基金financially supported by the National Natural Science Foundation of China(Nos.22272118,22172111,and 22309134)the Science and Technology Commission of Shanghai Municipality,China(Nos.22ZR1464100,20ZR1460300,and 19DZ2271500)+2 种基金the China Postdoctoral Science Foundation(2022M712402),the Shanghai Rising-Star Program(23YF1449200)the Zhejiang Provincial Science and Technology Project(2022C01182)the Fundamental Research Funds for the Central Universities(2023-3-YB-07)。
文摘Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains a confusing topic.Here we develop a hydrogen-bond-oriented interfacial super-assembly strategy to custom-tailor nanosheet-intertwined spherical carbon superstructures(SCSs)for Zn-ion storage with double-high capacitive activity and durability.Tetrachlorobenzoquinone(H-bond acceptor)and dimethylbenzidine(H-bond donator)can interact to form organic nanosheet modules,which are sequentially assembled,orientally compacted and densified into well-orchestrated superstructures through multiple H-bonds(N-H···O).Featured with rich surface-active heterodiatomic motifs,more exposed nanoporous channels,and successive charge migration paths,SCSs cathode promises high accessibility of built-in zincophilic sites and rapid ion diffusion with low energy barriers(3.3Ωs-0.5).Consequently,the assembled Zn||SCSs capacitor harvests all-round improvement in Zn-ion storage metrics,including high energy density(166 Wh kg-1),high-rate performance(172 m Ah g^(-1)at 20 A g^(-1)),and long-lasting cycling lifespan(95.5%capacity retention after 500,000 cycles).An opposite chargecarrier storage mechanism is rationalized for SCSs cathode to maximize spatial capacitive charge storage,involving high-kinetics physical Zn^(2+)/CF_(3)SO_(3)-adsorption and chemical Zn^(2+)redox with carbonyl/pyridine groups.This work gives insights into H-bond-guided interfacial superassembly design of superstructural carbons toward advanced energy storage.
基金supported by the National Natural Science Foundation of China(No.41975156).
文摘Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-linked-immunoassay(ELISA)method was developed to determine 3-NT in modified model protein(bovine serum albumin,BSA)and ambient aerosol samples.The nitration degrees(NDs)of BSA in the exposure experiments with different durations were detected by both the ELISA and spectrophotometric methods(i.e.,ND_(ELISA) and ND_(SEC-PDA)),which show good coincidence.The kinetic investigation by both ΔND_(ELISA) and ΔND_(SEC-PDA) in the exposure experiments shows that the rate coefficients(k)of the pseudo-first-order kinetic rate reactions of protein nitration were comparable.These results indicate that direct detection of 3-NT by the ELISA method can be applied for laboratory exposure samples analysis for kinetic studies.Based on the selective detection of 3-NT,ND_(ELISA) provides a promising measure for the assessment of ND in model proteins.3-NT was alsomeasured in PM_(2.5) samples in summer in Guangzhou,southern China,ranging from 10.1 to 404 pg/m^(3),providing clear evidence of protein nitration in ambient aerosols.We further proposed that 3-NT/protein can be used as a proxy to evaluate protein nitration in ambient aerosols.A significant correlationwas observed between 3-NT/protein and O_(3),confirming the crucial role of O_(3) in protein nitration.Our results show that the direct detection of 3-NT by the ELISA method can be more widely applied in the laboratory and field-based studies for understanding the mechanisms of protein nitration.
基金supported by the National Natural Science Foundation of China(No.22064014)the Science and Technology Development Plan Project of Lanzhou(No.2021–1-146)+2 种基金the Science and Technology Project of Gansu Province(Nos.21YF5FA071,21JR7RA538)the Industrial Support Programme for Higher Education Institutions Project(Nos.2023CYZC-69,2024CYCZ-05)the 2023 Gansu Provincial Key Talent Project(No.2023RCXM26)。
文摘The traditional nanozymes-based ratiometric fluorescence sensing platforms usually necessitate the supplementary addition of fluorescent probes,therefore greatly restricting its convenient and broad application.In this study,a highly sensitive and selective ratiometric fluorescence platform for alkaline phosphatase(ALP)detection was established,only employing Prussian blue(PB)nanozymes and a commercially available chromogen of o-phenylenediamine(OPD).PB nanozymes with remarkable peroxidaselike(POD-like)activity can effectively catalyze OPD chromogen to yield 2,3-diaminophenazine(OPDox)with an intense yellow fluorescence at 573 nm emission peak.Target ALP can facilitate ascorbic acid 2-phosphate(AAP)dephosphorylation to generate phosphate and ascorbic acid(AA).Significantly,both these two resultant hydrolysis products could effectively decrease the OPDox generation via a dualpath based inhibition on the PB nanozymes POD-like activity.On the other hand,the generated dehydroascorbic acid(DHAA)from AA oxidation would exclusively react with OPD chromogen to yield3-(dihydroxyethyl)furo[3,4-b]quinoxaline-1-one(DFQ)with a strong blue fluorescent signal at 434nm,which further providing a significant enhancement on the sensing selectivity of ALP detection.As a result,an increased yellow fluorescence of OPDox and decreased blue fluorescence of DFQ could be clearly observed with different ALP addition.A robust linear relationship between the fluorescence ratio of F_(434)/F_(573)and ALP activity ranging from 0.25U/L to 6U/L was obtained,with a low detection limit of 0.112 U/L.This proposed method demonstrates high sensitivity,excellent selectivity,cost-effectiveness,and operational simplicity,yet enabling an effective detection of ALP levels in human serum.
文摘In this work,we proposed a strategy for the hydrolysis of native corn starch after the treatment of corn starch in an ionic liquid aqueous solution,and it is an awfully“green”and simple means to obtain starch with low molecular weight and amorphous state.X-ray diffraction results revealed that the natural starch crystalline region was largely disrupted by ionic liquid owing to the broken intermolecular and intramolecular hydrogen bonds.After hydrolysis,the morphology of starch changed from particles of native corn starch into little pieces,and their molecular weight could be effectively regulated during the hydrolysis process,and also the hydrolyzed starch samples exhibited decreased thermal stability with the extension of hydrolysis time.This work would counsel as a powerful tool for the development of native starch in realistic applications.
文摘A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quinonemethides and their stereoisomers,impact the reactivity of cyclopropanation.The configurations at C9,C8,and C14 for all four pentacyclic diastereoisomers involved in the diastereoisomeric mixture were determined through a combination of suitable chemical derivatization and multiple NMR spectroscopic analyses.Based on the defined configuration,the 3D structures of these diastereoisomers were optimized by density functional theory(DFT)calculation.These investigations provide reasonable supports,mainly from the steric considerations,for understanding why different diastereoisomers exhibit markedly different reactivity,as well as regio-and stereo-selectivity for cyclopropanation.In addition,the mechanism for the construction of the spiroannulated 6-6-6-5-5 pentacyclic scaffold via intramolecular Michael/aldol cascade was also investigated by deuterium labeling experiments.
基金Supported by National Modern Agricultural Industry Technology System Sichuan Pig Innovation Team(SCCXTD-2026-8)Sichuan Science and Technology Program(2025ZYD0049)"Challenge and Leadership"Project for Key Core Technologies of Sui Ning in Sichuan(2025SNKBZ19).
文摘Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during frozen storage.Product indicators including pH,colour,thiobarbituric acid reactive substances(TBARS),total volatile basic nitrogen(TVB-N),texture,electronic nose(E-nose)response,and water-holding capacity(thawing and cooking losses)were determined.The results indicated that as storage time increased,water retention in Sichuan sausages with different moisture contents decreased,while the degree of protein and lipid oxidation increased.This led to an increase in pH value,a colour shift from red-bright to grey-brown,and a deterioration in palatability.Among the samples,sausages with 50% moisture content exhibited the lowest thawing and cooking losses,indicating superior water-holding capacity.After 8 weeks of storage,TBARS and TVB-N values for the 50% moisture group were 19.5%and 2.5%lower,respectively,than those of the 40%and 45%moisture groups,indicating a reduced degree of oxidation.Furthermore,Sichuan sausage with 50%moisture content demonstrated an appropriate pH and colour difference,along with excellent texture and flavour,as evidenced by its higher toughness and satisfactory hardness.In conclusion,Sichuan sausage with 50% moisture content demonstrated the highest overall quality under frozen storage conditions.
基金supported by the National Natural Science Foundation of China (Nos.82293682,82293684,and 82173703)。
文摘Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is crucial for the confirmation of absolute configurations.Ignoring critical parameters will lead to false structure,which may confuse the total synthesis and drug development.Herein,the configurations of seven heterogeneous Pallavicinia diterpenoids(PDs) isolated from Pallavicinia liverworts are revised using a combination of single-crystal X-ray diffraction and electronic circular dichroism(ECD) calculations.Meanwhile,identification of five unprecedented PD heterodimers PD-dimers A-E(18-22) along with eleven previously undescribed PDs(5-9,13-17,23) obtained by the reinvestigation of the Chinese liverwort Pallavicinia subciliata have resulted in corrections and support the revised conclusions.
基金funded by the National Key R&D Program of China under Grant(No.2022YFB3102901)National Natural Science Foundation of China(Nos.62072115,62102094)Shanghai Science and Technology Innovation Action Plan Project(No.22510713600).
文摘User identity linkage(UIL)across online social networks seeks to match accounts belonging to the same real-world individual.This cross-platformmapping enables accurate user modeling but also raises serious privacy risks.Over the past decade,the research community has developed a wide range of UIL methods,from structural embeddings tomultimodal fusion architectures.However,corresponding adversarial and defensive approaches remain fragmented and comparatively understudied.In this survey,we provide a unified overview of both mapping and antimappingmethods for UIL.We categorize representativemappingmodels by learning paradigmand datamodality,and systematically compare them with emerging countermeasures including adversarial injection,structural perturbation,and identity obfuscation.To bridge these two threads,we introduce amodality-oriented taxonomy and a formal gametheoretic framing that casts cross-network mapping as a contest between mappers and anti-mappers.This framing allows us to construct a cross-modality dependency matrix,which reveals structural information as themost contested signal,identifies node injection as the most robust defensive strategy,and points to multimodal integration as a promising direction.Our survey underscores the need for balanced,privacy-preserving identity inference and provides a foundation for future research on the adversarial dynamics of social identity mapping and defense.
基金supported by the National Science Foundationof China(Nos.52305127 and 52475130)。
文摘Early fault detection for spiral bevel gears is crucial to ensure normal operation and prevent accidents.The harmonic components,excited by the time-varying mesh stiffness,always appear in measured vibration signal.How to extract the periodical impulses that indicate gear localized fault buried in the intensive noise and interfered by harmonics is a challenging task.In this paper,a novel Periodical Sparse-Assisted Decoupling(PSAD)method is proposed as an optimization problem to extract fault feature from noisy vibration signal.The PSAD method decouples the impulsive fault feature and harmonic components based on the sparse representation method.The sparsity within and across groups property and the periodicity of the fault feature are incorporated into the regularizer as the prior information.The nonconvex penalty is employed to highlight the sparsity of fault features.Meanwhile,the weight factor based on2norm of each group is constructed to strengthen the amplitude of fault feature.An iterative algorithm with Majorization-Minimization(MM)is derived to solve the optimization problem.Simulation study and experimental analysis confirm the performance of the proposed PSAD method in extracting and enhancing defect impulses from noisy signal.The suggested method surpasses other comparative methods in extracting and enhancing fault features.
基金supported by the National Natural Science Foundation of China(Nos.52161145409,21976116)SAFEA of China("Belt and Road"Innovative Talent Exchange Foreign Expert Project No.2023041004L)+1 种基金(High-end Foreign Expert Project No.G2023041021L)Alexander-von-Humboldt Foundation of Germany(Group-Linkage Program).
文摘Photoreforming poly(lactic acid)(PLA)plastics into pyruvic acid(PA)coupled with hydrogen evolution is of great significance for sustainable development.However,a significant challenge lies inα-OH bond cleaving of lactic acid(LA).Herein,CdS/Bi_(4)Ti_(3)O_(12)composite is fabricated,bridged by Bi−S bonds,through in-situ growth of CdS nanoparticles on Bi_(4)Ti_(3)O_(12)nanoflowers for the successive removal of hydrogen fromα-C in LA.In-situ X-ray photoelectron spectroscopy confirms the S-scheme carriers transfer route and interfacial Bi−S bond in CdS/Bi_(4)Ti_(3)O_(12).Consequently,the photo-electrons and holes with extended lifetimes and strong redox potential accumulate in the CdS conduction band and Bi_(4)Ti_(3)O_(12)valence band,respectively,as evidenced by in-situ electron spin resonance and time-resolved photoluminescence.This facilitates the generation of·OH radicals,which further participate in the successive dehydrogenation reaction of LA.Consequently,the photoreforming efficiencies of converting PLA into PA and H_(2)by CdS/Bi_(4)Ti_(3)O_(12)are 1.7 and 3.16 mmol g^(-1)h^(-1),which are respectively 2.8 and 22 times higher than that by pristine Bi_(4)Ti_(3)O_(12).The present work provides a new approach for designing S-scheme to achieve hydrogen production and value-added conversion of plastics.
基金Supported by the Zhejiang Provincial Natural Science Foundation of China(No.LD21C030001)the Key Research and Development Program of National Natural Science Foundation of China(No.2021YFE0112000)+1 种基金the National Natural Science Foundation of China(Nos.32371634,31970219)the Scientific Research Project of the Shanghai Municipal Bureau of Ecology and Environment(No.202409)。
文摘Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in complex mountainous riverine reservoirs remain inadequately understood.We employed high-throughput sequencing of 16S and 18S ribosomal RNA genes,along with multivariate statistical methods to systematically investigate prokaryotic and eukaryotic microorganisms in the riverine Zhaoshandu Reservoir,Wenzhou,Zhejiang,East China.Results show significant temporal heterogeneity in both prokaryotic and eukaryotic microbial communities,with eukaryotic microbes showing more pronounced temporal variation.Canonical correspondence analysis revealed that rainfall and water temperature were the key drivers shaping microbial communities.Additionally,eukaryotic microorganisms exhibited a more pronounced response to rainfall and water temperature compared to prokaryotes.Modified stochasticity ratio model indicated that deterministic processes predominantly governed microbial community assembly,with stronger deterministic processes in eukaryotic compared to prokaryotic microorganisms.Rainfall has significantly altered water quality,notably increasing phosphorus concentration in the water column.Total phosphorus and total nitrogen showed significant correlations with the niche breadth of prokaryotic and eukaryotic microorganisms,and phosphorus nutrients served as keystones and playing indispensable roles in their co-occurrence networks.A structural equation model confirmed the notable impacts of rainfall and water temperature on microbial community diversity,further revealing that rainfall indirectly influenced the niche breadth and co-occurrence relationships of microbial communities by altering phosphorus concentrations.The findings underscore the influence of rainfall and water temperature on microbial distribution,highlighting the sensitivity of riverine reservoir ecosystems to climate change.
基金financially supported by the National Natural Science Foundation of China(No.52573053).
文摘Reactive compatibilization has been widely applied to enhance the compatibility of polymer blends,thereby improving their mechanical properties.However,it generally reduces the chain mobility and regularity,often leading to slower polymer crystallization.Here,we demonstrate that reactive compatibilization in poly(lactic acid)/poly(butylene adipate-co-terephthalate)(PLA/PBAT)blends unexpectedly promotes PLA matrix crystallization during injection molding,in contrast to the retarded kinetics observed in differential scanning calorimetry isothermal crystallization studies.The phase morphology,rheological behavior,and crystalline structure were systematically analyzed to elucidate markedly different crystallization kinetics under static and shear fields.The potential mechanism underlying crystallization enhancement is attributed to PBAT domain refinement and viscosity increase induced by reactive compatibilization,which,under shear flow,create favorable conditions for crystallization by enhancing PBAT fibril nucleation and retarding the relaxation of oriented PLA chains.This study offers new perspectives on the effect of reactive compatibilization on the polymer crystallization behavior.
基金supported by the National Natural Science Foundation of China(No.41975156)and the Fundamental Research Funds for the Central Universities.
文摘Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China in winter and spring of 2021.The results show that the average concentration of PM_(2.5) decreased by 47%from winter to spring,while volume-normalized and mass-normalized OP(i.e.,OP_(v) and OP_(m))increased by 6%and 69%,respectively.It suggests that the decline of PM_(2.5) may not necessarily decrease the health risks and the intrinsic toxicity of PM_(2.5).Variations of OP_(v) and OP_(m) among different periods were related to the different source contributions and environmental conditions.The positive matrix factorization model was used to identify the major sources of OP_(v).OP_(v) was mainly contributed by biomass burning/industrial emissions(29%),soil/road dust(20%),secondary sulfate(14%),and coal combustion(13%)in winter.Different major sources were resolved to be secondary sulfate(36%),biological sources(21%),and marine vessels(20%)in spring,presenting the substantial contribution of biological sources.The analysis shows strong associations between OP_(v) and both live and dead bacteria,further confirming the important contribution of bioaerosols to the enhancement of OP.This study highlights the importance of understanding OP in ambient PM_(2.5) in terms of public health impact and provides a new insight into the biological contribution to OP.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20220409)the National Natural Science Foundation of China(No.22401153)+2 种基金the FWO[Fund for Scientific Research-Flanders(Belgium)]for financial support(recipient Erik V.Van der Eycken)the Research Council of the KU Leuven(recipient Erik V.Van der Eycken)the support of the"RUDN University Strategic Academic Leadership Program"(recipient Erik V.Van der Eycken).
文摘Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face with their intrinsic limitations including metabolic instability and low membrane permeability,the strategies for synthesizing unnatural amino acids and peptides are explored.Among the methods for modifying amino acids and peptides,chemo-and site-selective approaches are preferred because of the ability to fine-tuning structural features.Recently,transition metal-catalyzed C–H activation has been employed for the functionalization of amino acids and peptides.Through domino C–H activation/annulation,a series of structurally complex and diverse amino acids and peptides is constructed.This review highlights recent advances in the synthesis of unnatural amino acids and peptides via transition metal-catalyzed C–H activation/annulation.
基金Project supported by the National Natural Science Foundation of China(52374292)the China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202309)the Natural Science Foundation of Changsha(KQ2208271)。
文摘To inhibit the interfacial(displacement)reaction between Hf and Al elements in the DZ125 superalloy and the Al_(2)O_(3) and SiO_(2) in the Al_(2)O_(3)-based ceramic shell,rare-earth oxides(La_(2)O_(3) and Y_(2)O_(3))were used as dopants into the shell.The effects of dopant types and contents(2 wt%,5 wt%and 8 wt%)on the wettability and interfacial reaction were investigated using the sessile-drop experiment,and the reaction products were analyzed by X-ray diffraction(XRD),a scanning electron microscope(SEM),an electron probe microanalyzer(EPMA)and X-ray photoelectron spectroscopy(XPS),to clarify the mechanism of dopants in the interracial reaction.The results show that increasing the Y_(2)O_(3) doping content(2 wt%-8 wt%)reduces the surface porosity from 22.39%to 13.43%,and decreases the surface roughness from 3.25 to 2.28μm,which enhances the packing density of the shell surface.In the sintering process(1223 K,2 h),both La_(2)O_(3) and Y_(2)O_(3) dopants react with SiO_(2),forming La_(2)Si_(2)O_(7) and Y_(2)SiO_(5) on the shell surface.During the interfacial reaction process(1823 K,40 min),La_(2)Si_(2)O_(7) decomposes and reacts with Al_(2)O_(3) and HfO_(2),resulting in the formation of SiO_(2)·HfO_(2)·La_(2)O_(3) and Al_(2)O_(3)·HfO_(2)·La_(2)O_(3) ternary composite oxides within the reaction products.At 8 wt%La_(2)O_(3) dopant content,the interfacial reaction is exacerbated,resulting in the uneven wettability.Y_(2)SiO_(5) further reacts with Al_(2)O_(3) and SiO_(2) to form SiO_(2)·Al_(2)O_(3)·Y_(2)O_(3) ternary composite oxides,while Y_(2)O_(3) combines with Al_(2)O_(3) to form Al_(5)Y_(3)O_(12)(VAG),which stabilizes the oxides within the shell and inhibits the interfacial reaction,and significantly improves the surface quality of the DZ125 superalloy.As the Y_(2)O_(3) dopant content increases(2 wt%-8 wt%),the wetting angle increases from 97.8°to 110.6°.
