期刊文献+
共找到125,511篇文章
< 1 2 250 >
每页显示 20 50 100
Enhanced selectivity of catalytic hydrogenation of halogenated nitroaromatics by interfacial effects
1
作者 HUANG Rui LIU Shengjie +1 位作者 WU Qingyuan ZHENG Nanfeng 《无机化学学报》 北大核心 2025年第1期201-212,共12页
The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts c... The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics. 展开更多
关键词 halogenated nitroaromatic heterogeneous catalysis HYDROGENATION selectivity control interfacial effect
在线阅读 下载PDF
Improved N_(2)selectivity for low-temperature NO_(x)reduction over etched ZSM-5 supported MnCe oxide catalysts
2
作者 Shanyuan Bi Jin Zhang +4 位作者 Dengchao Peng Danhong Cheng Jianping Zhang Lupeng Han Dengsong Zhang 《Chinese Chemical Letters》 2025年第5期639-644,共6页
Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we d... Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we demonstrate the improved low-temperature activity and N_(2)selectivity by regulating the redox and acidic properties of MnCe oxides supported on etched ZSM-5 supports.The etched ZSM-5 enables the highly dispersed state of MnCeOx species and strong interaction between Mn and Ce species,which promotes the reduction of CeO2,facilitates electron transfer from Mn to Ce,and generates more Mn^(4+)and Ce^(3+)species.The strong redox capacity contributes to forming the reactive nitrate species and-NH_(2)species from oxidative dehydrogenation of NH_(3).Moreover,the adsorbed NH_(3)and-NH_(2)species are the reactive intermediates that promote the formation of N_(2).This work demonstrates an effective strategy to enhance the low-temperature activity and N_(2)selectivity of SCR catalysts,contributing to the NO_(x)control for the low-temperature exhaust gas during the cold-start of diesel vehicles. 展开更多
关键词 NO_(x) selective catalytic reduction Mn-based catalyst Low-temperature activity N_(2)selectivity
原文传递
Confined electric field in nano-sized channels of ionic porous framework towards unique adsorption selectivity
3
作者 Congyan Liu Xueyao Zhou +2 位作者 Fei Ye Bin Jiang Bo Liu 《Chinese Chemical Letters》 2025年第2期437-441,共5页
Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are... Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are highly susceptible to framework charge,which plays a significant role in selective adsorption.Currently,ionic porous frameworks can be divided into two types.One of them is composed of a charged backbone and counter ions.The framework with zwitterionic channels is another type.It is composed of regular and alternating arrangements of cationic and anionic building units.Herein,we report a hydrogen-bonded ionic framework(HIF)of{(CN_(3)H_(6))_(2)[Ti(μ_(2)-O)(SO_(4))_(2)]}_nwith 1D channel exhibits unique adsorption selectivity for Ar against N_(2)and CO_(2).Density functional theory(DFT)results suggest that CO_(2)cannot be adsorbed by HIF at the experimental temperature due to a positive adsorption free energy.In addition,due to a relatively large diffusion barrier at 77 K,N_(2)molecules hardly diffuse in HIF channels,while Ar has a negligible diffusion barrier.The unique net positively-charged space in the channel is the key to the unusual phenomena,based on DFT simulations and structural analysis.The findings in this work proposes the new adsorption mechanism and provides unique perspective for special separation applications,such as isotope and noble gasses separations. 展开更多
关键词 Adsorption selectivity Channel Positive electric field GUANIDINIUM
原文传递
Food selectivity and autism:A systematic review
4
作者 Rosaria Ferrara Leonardo Iovino +3 位作者 Lidia Ricci Angiola Avallone Roberto Latina Pasquale Ricci 《World Journal of Clinical Pediatrics》 2025年第3期272-280,共9页
BACKGROUND Autism spectrum disorder(ASD)is a neurodevelopmental disorder that manifests in the first years of life,with a complex pathogenesis influenced by biological,genetic and epigenetic factors.Many children with... BACKGROUND Autism spectrum disorder(ASD)is a neurodevelopmental disorder that manifests in the first years of life,with a complex pathogenesis influenced by biological,genetic and epigenetic factors.Many children with ASD display marked food selectivity,often restricting themselves to a narrow range of foods.The problems associated with feeding children with ASD can vary widely,from mild cases that pose no immediate health risks,to more severe situations with a risk of mal-nutrition or,conversely,overeating.This scoping review aims to provide an in-depth overview of the frequency,nature and factors related to food selectivity in children with autism.AIM To comprehensively review the literature on food selectivity in ASD.METHODS A systematic review of the literature was conducted using the PubMed,Web of Science and EBSCO databases,to identify articles published in English from 2014 until 2024.Studies on a sample diagnosed with ASD and food selectivity were included.The selected databases were chosen for their broad coverage of the scientific literature.These databases represent reliable sources of high-quality articles,ensuring a comprehensive and up-to-date search.RESULTS We evaluated 222 studies on food selectivity in autism,from which duplicates were removed and unrelated titles were filtered out.Finally,9 articles were included in the review.Five articles provide a general overview of the phenomenon,analysing its nature and factors.Two studies delve into sensory sensitivity,in particular the impact of food textures,tastes and smells.Finally,two studies focus on problem behaviour during mealtimes.CONCLUSION Children with ASD have greater food selectivity than the neurotypical population.The diet should contain a greater variety of fruit,vegetables,yoghurt,while reducing the consumption of rice and pasta. 展开更多
关键词 Food selectivity AUTISM DEVELOPMENT Autism spectrum disorder CHILDREN
暂未订购
Breaking the selectivity barrier in glycerol electrooxidation to glyceraldehyde via redox mediation
5
作者 Zhenghao Mao Wenjing Xu +1 位作者 Na Han Yanguang Li 《Chinese Journal of Catalysis》 2025年第11期336-342,共7页
Aldehydes are valuable intermediates with widespread industrial applications,and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly.Electrochemical oxidatio... Aldehydes are valuable intermediates with widespread industrial applications,and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly.Electrochemical oxidation offers a more sustainable and milder alternative;however,it faces challenges such as aldehyde overoxidation and susceptibility to base-catalyzed Cannizzaro disproportionation.Electrochemical glycerol oxidation to glyceraldehyde is a representative example,which typically requires precious metal-based electrocatalysts but still suffers from low selectivity and activity.Here,we report a metal-free oxidation strategy mediated by 2,2,6,6-tetramethylpiperidine-1-oxyl.By systematically investigating the redox thermodynamics and kinetics of TEMPO across a broad pH range,we construct a Pourbaix diagram and elucidate the relative kinetics of each reaction step.These insights allow us to explain the anomalously high apparent Faradaic efficiency(~200%)observed under acidic conditions,and identify neutral media as the optimal environment for selective glyceraldehyde production.Under optimized conditions,our system achieves a glyceraldehyde Faradaic efficiency exceeding 93%and a partial current density of 23.3 mA cm^(-2)at 0.57 V—more than doubling the performance of the best reported precious metal-based systems.Furthermore,the versatility of this strategy extends to the selective oxidation of other primary alcohols to their corresponding aldehydes with near-unity selectivity. 展开更多
关键词 Electrochemical glycerol oxidation GLYCERALDEHYDE Redox mediator selectivity Pourbaix diagram
在线阅读 下载PDF
Biosorption selectivity of rare earth elements onto Euglena mutabilis suspensions and biofilms and the effect of divalent metal ions
6
作者 Mitchell T.E.Zak Vladimiros G.Papangelakis D.Grant Allen 《Journal of Rare Earths》 2025年第10期2269-2275,I0007,共8页
The increasing demand for electronics has led to a desire to recover rare earth elements(REEs) from nonconventional sources,including mining and liquid waste effluents.Biosorption could be a promising method for adsor... The increasing demand for electronics has led to a desire to recover rare earth elements(REEs) from nonconventional sources,including mining and liquid waste effluents.Biosorption could be a promising method for adsorbing REEs onto microalgae,but biomass immobilization and light delivery challenges remain.It was recently shown that REEs biosorb 160% more on algal biofilms than suspended biomass due to the extracellular polymeric substance(EPS) matrix that grows abundantly in biofilms.In this work,we present findings on biosorption selectivity for different REEs in sulfate solutions.The maximum adsorption capacities of Euglena mutabilis suspensions and biofilms were determined for a mixed REE sulfate solution at an equimolar initial concentration range of 0.1-1 mol/L of each REE ion.The highest adsorption capacities for the suspension are for Sm and Eu which are 57% and 46% higher,respectively,compared to the average REE adsorption capacity.The biofilms also preferentially adsorb Sm,Eu,Yb and Lu at 0.035,0.033,0.033,and 0.031 mmol/g,respectively.The impact of dissolved divalent ions of Ca,Mg,and Fe on REE adsorption was also assessed.When Ca and Mg are added in equimolar amounts to0.1-1 mmol/L solutions of equimolar La,Eu,and Yb sulfate,the amount of REEs adsorbed onto suspensions increases by 30% while when Fe is added,it decreases by 10%.No change is observed in biofilms except when Fe is added resulting in a reduction of the adsorption capacity by 40%.A possible explanation for the role of Fe is attributed to the formation of stronger bonds at the binding sites compared to Ca and Mg. 展开更多
关键词 Algal biofilm BIOSORPTION Extracellular polymeric substances Rare earth element selectivity
原文传递
Indium-captured zirconium-porphyrin frameworks displaying rare multi-selectivity for catalytic transfer hydrogenation of aldehydes and ketones
7
作者 Hua Liu Jian Zhao +5 位作者 Qi Li Xiang-Yu Zhang Zhi-Wei Zheng Kun Huang Da-Bin Qin Bin Zhao 《Chinese Chemical Letters》 2025年第6期648-656,共9页
Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but ful... Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but full of great challenge.Herein,a cationic In-captured Zr-porphyrin framework(1)with nanosized pores/cages was successfully constructed and showed high structure stability.Catalytic investigations revealed that 1 displayed highly multi-selective CTH of aldehydes and ketones containing both chemo-and size selectivity for the first time.The CTH of aldehydes and ketones exhibited remarkable reductive selectivity of 99%towards C=O bonds into CH–OH in the presence of-NO_(2),-CN and C=C groups.Through tuning the reaction conditions,1 also exhibited highly selective reduction of 97%for-CHO groups in the simultaneous presence of-CHO and-COCH3groups in intra-and intermolecular settings.Remarkably,reductive selectivity towards-CHO group remained prominent among five concurrent unsaturated groups mentioned above.Additionally,the definite pore size of 1 facilitated volume control of substrates,enabling size selectivity.1 as a heterogeneous catalyst was further confirmed by leaching tests,and maintained high activity even after being used for at least six cycles.Mechanistic studies have revealed that Zr6O8clusters served as the catalytic centers and the observed chemoselectivity mainly results from the synergistic effect of distinct metal sites within 1.The heightened selectivity towards-CHO over-COCH_(3)can be attributed to the easier realization of transfer hydrogenation processes for-CHO compared to-COCH_(3). 展开更多
关键词 Metal-organic framework Heterogeneous catalysis Transfer hydrogenation Multiple selectivity Synergistic effect
原文传递
2D copper-iron bimetallic metal-organic frameworks for reduction of nitrate with boosted efficiency and ammonia selectivity
8
作者 Qian Ma Yinghao Xue +4 位作者 Chuning Zhang Yanyan Chen Wei Teng Hua Zhang Jianwei Fan 《Journal of Environmental Sciences》 2025年第3期374-385,共12页
Electrocatalytic reduction of nitrate to ammonia has been considered a promising and sustainable pathway for pollutant treatment and ammonia has significant potential as a clean energy.Therefore,the method has receive... Electrocatalytic reduction of nitrate to ammonia has been considered a promising and sustainable pathway for pollutant treatment and ammonia has significant potential as a clean energy.Therefore,the method has received much attention.In this work,Cu/Fe 2D bimetallic metal-organic frameworks were synthesized by a facile method applied as cathode materials without high-temperature carbonization.Bimetallic centers(Cu,Fe)with enhanced intrinsic activity demonstrated higher removal efficiency.Meanwhile,the 2D nanosheet reduced themass transfer barrier between the catalyst and nitrate and increased the reaction kinetics.Therefore,the catalysts with a 2D structure showed much better removal efficiency than other structures(3D MOFs and BulkMOFs).Under optimal conditions,Cu/Fe-2D MOF exhibited high nitrate removal efficiency(87.8%)and ammonium selectivity(89.3%)simultaneously.The ammonium yielded up to significantly 907.2μg/(hr·mg_(cat))(7793.8μg/(hr·mg_(metal)))with Faradaic efficiency of 62.8%at an initial 100 mg N/L.The catalyst was proved to have good stability and was recycled 15 times with excellent effect.DFT simulations confirm the reduced Gibbs free energy of Cu/Fe-2D MOF.This study demonstrates the promising application of Cu/Fe-2D MOF in nitrate reduction to ammonia and provides new insights for the design of efficient electrode materials. 展开更多
关键词 Metal-organic frameworks Electrochemical denitrification Ammonium selectivity 2D bimetal materials
原文传递
Surface oxygen vacancies of BiOBr regulating piezoelectricity for enhancing efficiency and selectivity of photocatalytic CO_(2) reduction
9
作者 Cunjun Li Jie He +4 位作者 Tianle Cai Xianlei Chen Hengcong Tao Yingtang Zhou Mingshan Zhu 《Chinese Journal of Catalysis》 2025年第7期130-143,共14页
Although defect engineering has been widely used to boost catalytic CO_(2) photoreduction,the piezoelectric polarized properties induced by structure changes through introducing defects are always ignored.Here we repo... Although defect engineering has been widely used to boost catalytic CO_(2) photoreduction,the piezoelectric polarized properties induced by structure changes through introducing defects are always ignored.Here we report a new kind of bismuth oxybromide(BiOBr,BOB)with piezoelectric property regulated by oxygen vacancies(OVs).Compared with pure BOB,BOB with OVs(BOB-OV)could enhance photocatalytic CO_(2) reduction efficiency under the ultrasonic force,achieving durable CO_(2) reduction process to superior production rates of CO(54.4μmol g^(-1) h^(-1))with a high selectivity(92%).Moderate OVs concentration changed the degree of Bi-Br stretching in the BOB-OV to produce strong dipole moments,which endowed BOB-OV with strong spontaneous piezoelectric polarization ability under external force.Ultrasonic piezoelectric effects were innovatively integrated into the photocatalytic reaction,which not only provided an alternating force field to modulate the spontaneous polarization of BOB-OV,thereby maintaining efficient photogenerated charge separation,but also lowered the reaction energy barrier of CO_(2) by high stress,ultimately improving CO product selectivity.This study is the first to leverage OVs-induced piezoelectric polarization effects to enhance the performance and product selectivity of photocatalytic CO_(2) reduction,providing new directions and insights for defect engineering to contribute to photocatalysis. 展开更多
关键词 BiOBr Oxygen vacancy PIEZOELECTRICITY High selectivity Photocatlytic CO_(2)reduction
在线阅读 下载PDF
A stable scandium(III) metal-organic framework with introduced nitrate ions for enhancing C_(2)H_(6)/C_(2)H_(4) selectivity in the separation of MTO products
10
作者 Yajun Gao Xinyu Yang +1 位作者 Jian Su Zhizhong Li 《Chinese Journal of Structural Chemistry》 2025年第6期18-25,共8页
Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;... Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;AEU for Army Engineering University of PLA),was synthesized,which shows good water and chemical stabilities.Significantly,due to channel constriction accompanied by the polar window caused by introducing nitrate ions,AEU-1 exhibits high C_(2)H_(6)/C_(2)H_(4)adsorption selectivity comparable to many famous C_(2)H_(6)-selective MOFs,making it a promising candidate for the purification of methanol-to-olefin(MTO)products.Furthermore,theoretical investigations reveal that the introduced nitrate ions in AEU-1 as the main adsorption sites could provide strong interactions between the framework and C2H6/C3H6 in the full-contacting mode,leading to an increase in the adsorption enthalpies(Qst)of C_(2)H_(6)and C_(3)H_(6),and thus further improving the C_(2)H_(6)/C_(2)H_(4)and C_(3)H_(6)/C_(2)H_(4)adsorption selectivity.Our work could open up a new avenue for constructing MOFs with inorganic polar moieties as adsorption sites for one-step C_(2)H_(4)purification and C3H6 recovery from MTO mixtures with high selectivity. 展开更多
关键词 Scandium(III)metal-organic framework Nitrate ions selectivity MTO product separation
原文传递
Ecological Dynamics of a Logistic Population Model with Impulsive Age-selective Harvesting
11
作者 DAI Xiangjun JIAO Jianjun 《应用数学》 北大核心 2026年第1期72-79,共8页
In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asy... In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asymptotic stability of the trivial solution and the positive periodic solution.Finally,numerical simulations are presented to validate our results.Our results show that age-selective harvesting is more conducive to sustainable population survival than non-age-selective harvesting. 展开更多
关键词 The logistic population model selective harvesting Asymptotic stability EXTINCTION
在线阅读 下载PDF
Vibrational Mode Selectivity in Dissociative Ionization of 2-Ethoxyethanol:An IR-VUV NRIFD-IR Spectroscopic Study
12
作者 Licheng Zhong Ende Huang +3 位作者 Guosheng Wang Jingning Xue Wenrui Dong Xueming Yang 《Chinese Journal of Chemical Physics》 2025年第2期156-163,I0002-I0006,I0039,共14页
In the current work,we studied the infrared spectroscopy of neutral and cationic 2-ethoxyethanol(CH_(3)CH_(2)O CH_(2)CH_(2)OH,2-EE)using the infrared(IR)-vacuum-ultraviolet(VUV)non-resonant ionization and fragmenta-ti... In the current work,we studied the infrared spectroscopy of neutral and cationic 2-ethoxyethanol(CH_(3)CH_(2)O CH_(2)CH_(2)OH,2-EE)using the infrared(IR)-vacuum-ultraviolet(VUV)non-resonant ionization and fragmenta-tion detected IR spectroscopy(NRIFD-IR)technique.The spectral range was from 2700 cm^(−1)to 7250 cm^(−1).Upon radiation with a 118 nm laser,signals corresponding to the cationic 2-EE(m/z=90)and dissociative ioniza-tion products(m/z=72,59,46,and 45)were detected.The action IR spectra,derived from the signal variations of 2-EE and its fragments upon IR radiation,display differences,suggest-ing vibrational mode selectivity in the dissociative ionization process.To complement the ex-perimental findings,we performed density functional theory calculations at the B3LYP-D3(BJ)/def2-TZVPP level to determine the structures and anharmonic IR spectra of neutral and cationic 2-EE.The computed spectra showed good agreement with the experimental re-sults. 展开更多
关键词 Gas phase infrared spectroscopy Neutral and cationic molecular structure Vi-brational mode selectivity
在线阅读 下载PDF
MOF encapsulation derived slow-release oxygen species to enhance the activity and selectivity of methane selective oxidation:A transient DRIFTs Study
13
作者 Ke-Xin Li Hao Yuan +1 位作者 Ralph T.Yang Zhun Hu 《Chinese Journal of Catalysis》 2025年第11期202-214,共13页
The methane selective oxidation was a"holy grail"reaction.However,peroxidation and low selectivity limited the application.Herein,we combined three Au contents with TiO_(2)in both encapsulation(xAu@TiO_(2))a... The methane selective oxidation was a"holy grail"reaction.However,peroxidation and low selectivity limited the application.Herein,we combined three Au contents with TiO_(2)in both encapsulation(xAu@TiO_(2))and surface-loaded(xAu/TiO_(2))ways by MOF derivation strategy,reported a catalyst 0.5Au@TiO_(2)exhibited a CH_(3)OH yield of 32.5μmol·g^(-1)·h^(-1)and a CH_(3)OH selectivity of 80.6%under catalytic conditions of only CH_(4),O_(2),and H_(2)O.Mechanically speaking,the catalytic activity was controlled by both electron-hole separation efficiency and core-shell structure.The interfacial contact between Au nanoparticles and TiO_(2)in xAu@TiO_(2)and xAu/TiO_(2)induced the formation of oxygen vacancies,with 0.5 Au content showing the highest oxygen vacancy concentration.At the same Au content,xAu@TiO_(2)generated more oxygen vacancies than xAu/TiO_(2).The oxygen vacancy acted as an effective electron cold trap,which enhanced the photogenerated carrier separation efficiency and thereby improved the catalytic activity.In-situ DRIFTs revealed that the isolated OH(non-hydrogen bond adsorption)were key species for the methane selective oxidation,playing a role in the activation of CH_(4)to^(*)CH_(3).However,an overabundance of isolated OH led to severe overoxidation.Fortunately,the core-shell structure over xAu@TiO_(2)provided a slow-release environment for isolated OH through the intermediate state of^(*)OH(hydrogen bond adsorption)to balance the formation rate and consumption rate of isolated OH,doubling the methanol yield and increasing the>29%selectivity.These results showed a new strategy for the control of the overoxidation rate via a strategy of MOF encapsulation followed by pyrolytic derivation for methane selective oxidation. 展开更多
关键词 Methane selective oxidation Metal-organic framework derived Reactive oxygen species modulation Hydrogen bonded adsoprotion hydroxyl groups
在线阅读 下载PDF
Mechanical Anisotropy of Ti-6Al-4V Alloy Fabricated by Selective Laser Melting
14
作者 Liu Junwei Liu Zhenya +3 位作者 Fan Caihe Ou Ling He Wuqiang Ma Wudan 《稀有金属材料与工程》 北大核心 2026年第1期35-46,共12页
To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the... To explore the formation mechanism of anisotropy in Ti-6Al-4V alloy fabricated by selective laser melting(SLM),the compressive mechanical properties,microhardness,microstructure,and crystallographic orientation of the alloy across different planes were investigated.The anisotropy of SLM-fabricated Ti-6Al-4V alloys was analyzed,and the electron backscatter diffraction technique was used to investigate the influence of different grain types and orientations on the stress-strain distribution at various scales.Results reveal that in room-temperature compression tests at a strain rate of 10^(-3) s^(-1),both the compressive yield strength and microhardness vary along the deposition direction,indicating a certain degree of mechanical property anisotropy.The alloy exhibits a columnar microstructure;along the deposition direction,the grains appear equiaxed,and they have internal hexagonal close-packed(hcp)α/α'martensitic structure.α'phase has a preferential orientation approximately along the<0001>direction.Anisotropy arises from the high aspect ratio of columnar grains,along with the weak texture of the microstructure and low symmetry of the hcp crystal structure. 展开更多
关键词 selective laser melting TI-6AL-4V ANISOTROPY crystal orientation
原文传递
Bond-Selective Chemistry:a Foundation for Bond-Selective Imaging
15
作者 Ji-Xin Cheng 《Chinese Journal of Chemical Physics》 2026年第1期3-8,共6页
Dear Editors,This letter,reflecting on my research career,is dedi-cated to Professor Qingshi Zhu for his 80th Birthday.Part of this letter is based on my comment“A 20-year journey on the invention of vibrational phot... Dear Editors,This letter,reflecting on my research career,is dedi-cated to Professor Qingshi Zhu for his 80th Birthday.Part of this letter is based on my comment“A 20-year journey on the invention of vibrational photothermal microscopy”published in the May 2025 Nature Meth-ods Focus Issue on Bond-Selective Imaging[1]. 展开更多
关键词 bond selective chemistry vibrational photothermal microscopy published vibrational photothermal microscopy bond selective imaging research career Professor Qingshi Zhu
在线阅读 下载PDF
Detecting Anomalies in FinTech: A Graph Neural Network and Feature Selection Perspective
16
作者 Vinh Truong Hoang Nghia Dinh +3 位作者 Viet-Tuan Le Kiet Tran-Trung Bay Nguyen Van Kittikhun Meethongjan 《Computers, Materials & Continua》 2026年第1期207-246,共40页
The Financial Technology(FinTech)sector has witnessed rapid growth,resulting in increasingly complex and high-volume digital transactions.Although this expansion improves efficiency and accessibility,it also introduce... The Financial Technology(FinTech)sector has witnessed rapid growth,resulting in increasingly complex and high-volume digital transactions.Although this expansion improves efficiency and accessibility,it also introduces significant vulnerabilities,including fraud,money laundering,and market manipulation.Traditional anomaly detection techniques often fail to capture the relational and dynamic characteristics of financial data.Graph Neural Networks(GNNs),capable of modeling intricate interdependencies among entities,have emerged as a powerful framework for detecting subtle and sophisticated anomalies.However,the high-dimensionality and inherent noise of FinTech datasets demand robust feature selection strategies to improve model scalability,performance,and interpretability.This paper presents a comprehensive survey of GNN-based approaches for anomaly detection in FinTech,with an emphasis on the synergistic role of feature selection.We examine the theoretical foundations of GNNs,review state-of-the-art feature selection techniques,analyze their integration with GNNs,and categorize prevalent anomaly types in FinTech applications.In addition,we discuss practical implementation challenges,highlight representative case studies,and propose future research directions to advance the field of graph-based anomaly detection in financial systems. 展开更多
关键词 GNN SECURITY ECOMMERCE FinTech abnormal detection feature selection
在线阅读 下载PDF
FedCW: Client Selection with Adaptive Weight in Heterogeneous Federated Learning
17
作者 Haotian Wu Jiaming Pei Jinhai Li 《Computers, Materials & Continua》 2026年第1期1551-1570,共20页
With the increasing complexity of vehicular networks and the proliferation of connected vehicles,Federated Learning(FL)has emerged as a critical framework for decentralized model training while preserving data privacy... With the increasing complexity of vehicular networks and the proliferation of connected vehicles,Federated Learning(FL)has emerged as a critical framework for decentralized model training while preserving data privacy.However,efficient client selection and adaptive weight allocation in heterogeneous and non-IID environments remain challenging.To address these issues,we propose Federated Learning with Client Selection and Adaptive Weighting(FedCW),a novel algorithm that leverages adaptive client selection and dynamic weight allocation for optimizing model convergence in real-time vehicular networks.FedCW selects clients based on their Euclidean distance from the global model and dynamically adjusts aggregation weights to optimize both data diversity and model convergence.Experimental results show that FedCW significantly outperforms existing FL algorithms such as FedAvg,FedProx,and SCAFFOLD,particularly in non-IID settings,achieving faster convergence,higher accuracy,and reduced communication overhead.These findings demonstrate that FedCW provides an effective solution for enhancing the performance of FL in heterogeneous,edge-based computing environments. 展开更多
关键词 Federated learning non-IID client selection weight allocation vehicular networks
在线阅读 下载PDF
Radical-induced selective oxidation and depression of pyrite in copper flotation
18
作者 Richard Li Jie Lee Wen-Da Oh +1 位作者 Zhiyong Gao Yongjun Peng 《International Journal of Minerals,Metallurgy and Materials》 2026年第2期507-517,共11页
Selective depression of pyrite remains a major bottleneck in copper flotation,particularly when high-pyrite ores are processed and saline water is used.In such environments,conventional approaches using lime and inert... Selective depression of pyrite remains a major bottleneck in copper flotation,particularly when high-pyrite ores are processed and saline water is used.In such environments,conventional approaches using lime and inert grinding media often fail to discriminate ef-fectively between pyrite and valuable copper minerals due to strong copper activation on pyrite surfaces.This study introduced a novel approach using inorganic radicals generated from peroxymonosulfate(PMS)to selectively oxidize and depress pyrite.Flotation tests with synthetic high-pyrite ore blends showed that PMS significantly reduced pyrite recovery while maintaining or improving chalcopyrite flot-ation.Ethylenediaminetetraacetic acid(EDTA)extraction confirmed selective oxidation of pyrite,and electron paramagnetic resonance(EPR)spectroscopy identified hydroxyl(·OH)and sulfate(SO_(4)^(·-))radicals as the dominant reactive species.Iron ions from grinding me-dia and mineral surfaces were identified as key activators of PMS.A major insight was pyrite’s dual role,acting both as a radical scav-enger and an activator,which made it highly reactive and susceptible to radical-induced oxidation.This process converted surface copper-sulfur species into copper hydroxides,effectively suppressing pyrite flotation.While previous studies have applied EPR to detect radicals in simplified activator/precursor systems,this study provides the first direct mechanistic evidence of radical-driven selectivity in flotation by detecting inorganic radicals in a complex flotation slurry,thereby demonstrating their persistence under industrially relevant conditions and establishing a foundation for more effective and targeted flotation strategies. 展开更多
关键词 selective flotation radical oxidation PEROXYMONOSULFATE pyrite depression chalcopyrite recovery
在线阅读 下载PDF
A Unified Feature Selection Framework Combining Mutual Information and Regression Optimization for Multi-Label Learning
19
作者 Hyunki Lim 《Computers, Materials & Continua》 2026年第4期1262-1281,共20页
High-dimensional data causes difficulties in machine learning due to high time consumption and large memory requirements.In particular,in amulti-label environment,higher complexity is required asmuch as the number of ... High-dimensional data causes difficulties in machine learning due to high time consumption and large memory requirements.In particular,in amulti-label environment,higher complexity is required asmuch as the number of labels.Moreover,an optimization problem that fully considers all dependencies between features and labels is difficult to solve.In this study,we propose a novel regression-basedmulti-label feature selectionmethod that integrates mutual information to better exploit the underlying data structure.By incorporating mutual information into the regression formulation,the model captures not only linear relationships but also complex non-linear dependencies.The proposed objective function simultaneously considers three types of relationships:(1)feature redundancy,(2)featurelabel relevance,and(3)inter-label dependency.These three quantities are computed usingmutual information,allowing the proposed formulation to capture nonlinear dependencies among variables.These three types of relationships are key factors in multi-label feature selection,and our method expresses them within a unified formulation,enabling efficient optimization while simultaneously accounting for all of them.To efficiently solve the proposed optimization problem under non-negativity constraints,we develop a gradient-based optimization algorithm with fast convergence.Theexperimental results on sevenmulti-label datasets show that the proposed method outperforms existingmulti-label feature selection techniques. 展开更多
关键词 feature selection multi-label learning regression model optimization mutual information
在线阅读 下载PDF
High‑density genetic mapping enhances genomic selection accuracy for complex traits in Populus
20
作者 Chenchen Guo Tongming Yin Suyun Wei 《Journal of Forestry Research》 2026年第2期290-304,共15页
Populus species,important economic species combining rapid growth with broad ecological adaptability,play a critical role in sustainable forestry and bioenergy production.In this study,we performed whole-genome resequ... Populus species,important economic species combining rapid growth with broad ecological adaptability,play a critical role in sustainable forestry and bioenergy production.In this study,we performed whole-genome resequencing of 707 individuals from a full-sib family to develop comprehensive single nucleotide polymorphism(SNP)markers and constructed a high-density genetic linkage map of 19 linkage groups.The total genetic length of the map reached 3623.65 cM with an average marker interval of 0.34 cM.By integrating multidimensional phenotypic data,89 quantitative trait loci(QTL)associated with growth,wood physical and chemical properties,disease resistance,and leaf morphology traits were identified,with logarithm of odds(LOD)scores ranging from 3.13 to 21.72 Notably,pleiotropic analysis revealed significant colocaliza and phenotypic variance explained between 1.7% and 11.6%.-tion hotspots on chromosomes LG1,LG5,LG6,LG8,and LG14,with epistatic interaction network analysis confirming genetic basis of coordinated regulation across multiple traits.Functional annotation of 207 candidate genes showed that R2R3-MYB and bHLH transcription factors and pyruvate kinase-encoding genes were significantly enriched,suggesting crucial roles in lignin biosynthesis and carbon metabolic pathways.Allelic effect analysis indicated that the frequency of favorable alleles associated with target traits ranged from 0.20 to 0.55.Incorporation of QTL-derived favorable alleles as random effects into Bayesian-based genomic selection models led to an increase in prediction accuracy ranging from 1% to 21%,with Bayesian ridge regression as the best predictive model.This study provides valuable genomic resources and genetic insights for deciphering complex trait architecture and advancing molecular breeding in poplar. 展开更多
关键词 Genomic selection Genetic map Quantitative trait loci GROWTH Disease resistance
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部