期刊文献+
共找到4,532篇文章
< 1 2 227 >
每页显示 20 50 100
A Fast Algorithm of Scalar Multiplication Based on Side-Channel Atomicity
1
作者 郝玉洁 殷石 《China Communications》 SCIE CSCD 2011年第2期134-139,共6页
Simple power analysis is the most devastating attack on the security of elliptic curve scalar multiplication and can probably retrieve the secret key. In this paper,we analyze the formulas of point doubling and additi... Simple power analysis is the most devastating attack on the security of elliptic curve scalar multiplication and can probably retrieve the secret key. In this paper,we analyze the formulas of point doubling and addition on Jacobi-quartic Curve in projective coordination. In addition,a fast and secure side-channel atomic scalar multiplication algorithm is proposed using the side-channel atomic block. Compared with the previous methods,the new algorithm is more efficient. For 192 bits scalar using NAF recoding,the efficiency of the new algorithm is increased by about 6.7%~23% if S/M=0.8 or 12.7%~33.2% if S/M=0.6. 展开更多
关键词 jacobi-quartic curve scalar multipli-cation simple power analysis side-channel atomicity
在线阅读 下载PDF
Clarifying atomicity-activity relations of platinum clusters for oxygen reduction reaction
2
作者 Qingdan Ding Shiyu Dai Wei Ma 《Science China Materials》 2025年第6期1847-1855,共9页
Platinum clusters(Pt_(n))are extensively used as electrocatalysts for oxygen reduction reaction(ORR)because they provide excellent performance together with a reduced Pt requirement.However,the precise synthesis and a... Platinum clusters(Pt_(n))are extensively used as electrocatalysts for oxygen reduction reaction(ORR)because they provide excellent performance together with a reduced Pt requirement.However,the precise synthesis and atomic-level insights into the structure-activity relationship of Pt_(n) remain a great challenge.Here,we present a combinatorial synthesis and analysis method to investigate the atomicity-activity relationships of Pt_(n) at the individual level.We employ single nanoparticle collision electrochemistry to facilitate the in-situ electrodeposition of a single precisely tunable Pt_(n) on the graphene quantum dot support,followed by instantaneous measurement of the intrinsic ORR activity of the resulting Pt_(n).By relying on highly sensitive electrochemical measurements,our investigations clarify the atomicity-specific ORR activity of Pt_(n),which is attributed to their distinct geometric and electronic structures at varying cluster sizes.Significantly,Pt_(n) with low atomicity,especially below 20,can reach extraordinarily high ORR activities due to atom-by-atom arrangement.Our work provides a simple and efficient method for investigating the atomicity-activity relationships of other nanoclusters under real reaction conditions,enabling a better design of the electrocatalysts at the atomic level. 展开更多
关键词 atomicity-activity relation atomically precise Pt nanoclusters oxygen reduction reaction
原文传递
Mixed Quasi-martingale Hardy Spaces
3
作者 ZHANG Chuanzhou LI Shimeng HE Zhibin 《应用数学》 北大核心 2026年第1期221-231,共11页
In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale in... In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale inequalities of mixed quasi-martingale Hardy spaces.Moreover,we furnish sufficient conditions for the boundedness ofσ-sublinear operators in these spaces.These findings extend the existing conclusions regarding mixed quasi-martingale Hardy spaces defined with the help of the mixed L_(p)-norm. 展开更多
关键词 Mixed quasi-martingale Hardy space Atomic Decomposition σ-sublinear operator
在线阅读 下载PDF
Optimizing Magnetic Performance and Microstructure of CoPt Nanoparticles by Sol-Gel Synthesis
4
作者 WANG Xinchi WANG Wei +2 位作者 LIU Shuai WANG Yun LI Baohe 《Journal of Wuhan University of Technology(Materials Science)》 2026年第1期8-14,共7页
We prepared Co_(x)Pt_(100-x)(x=40,45,50,55,60)nanoparticles by the sol-gel method.The phase composition and crystal structure,morphology and microstructure,and magnetic properties of the samples were characterized and... We prepared Co_(x)Pt_(100-x)(x=40,45,50,55,60)nanoparticles by the sol-gel method.The phase composition and crystal structure,morphology and microstructure,and magnetic properties of the samples were characterized and tested using X-ray diffraction(XRD),transmission electron microscopy(TEM),and vibrating sample magnetometer(VSM),respectively.The results demonstrate that the coercivity of CoPt nanoparticles can be effectively controlled by adjusting the atomic ratio of Co and Pt in the samples.Among the compositions studied,the Co_(45)Pt_(55)sample synthesized by the sol-gel method exhibits smaller grain size and a coercivity as high as 6.65×10^(5) A/m is achieved.The morphology and microstructure of the nanoparticles were analyzed by TEM images,indicating that a slight excess of Pt can effectively enhance the coercivity of CoPt nanoparticles. 展开更多
关键词 COPT sol-gel method atomic ratio magnetic nanoparticles COERCIVITY
原文传递
P,N co-doped hollow carbon nanospheres prepared by micellar copolymerization for increased hydrogen evolution in alkaline water 被引量:1
5
作者 HAN Yi-meng XIONG Hao +2 位作者 YANG Jia-ying WANG Jian-gan XU Fei 《新型炭材料(中英文)》 北大核心 2025年第1期211-221,共11页
The design of cost-effective and efficient metal-free carbon-based catalysts for the hydrogen evolution reaction(HER)is of great significance for increasing the production of clean hydrogen by the electrolysis of alka... The design of cost-effective and efficient metal-free carbon-based catalysts for the hydrogen evolution reaction(HER)is of great significance for increasing the production of clean hydrogen by the electrolysis of alkaline water.Precise control of the electronic structure by heteroatom doping has proven to be efficient for increasing catalytic activity.Nevertheless,both the structural characteristics and the underlying mechanism are not well understood,especially for doping with two different atoms,thus limiting the use of these catalysts.We report the production of phosphorus and nitrogen co-doped hollow carbon nanospheres(HCNs)by the copolymerization of pyrrole and aniline at a Triton X-100 micelle-interface,followed by doping with phytic acid and carbonization.The unique pore structure and defect-rich framework of the HCNs expose numerous active sites.Crucially,the combined effect of graphitic nitrogen and phosphorus-carbon bonds modulate the local electronic structure of adjacent C atoms and facilitates electron transfer.As a res-ult,the HCN carbonized at 1100°C exhibited superior HER activity and an outstanding stability(70 h at a current density of 10 mA cm^(−2))in alkaline water,because of the large number of graphitic nitrogen and phosphorus-carbon bonds. 展开更多
关键词 Alkaline hydrogen evolution ELECTROCATALYSTS Hollow carbon nanospheres Dual atoms doping Combined effect
在线阅读 下载PDF
Cu-Catalyzed Regioselective Heteroarylation of C(sp^(3))—H Bond Induce by Sulfonyl Group 被引量:1
6
作者 Liu Huiying Wu Zhongtian +1 位作者 Li Haotian Wu Xinxin 《有机化学》 北大核心 2025年第1期297-306,共10页
The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydr... The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydrogen atom transfer strategy involving radicals has garnered considerable attention from chemists due to its high chemoselectivity and regioselectivity.However,owing to the marginal differences in bond dissociation energies(BDEs)among C(sp^(3))—H bonds,hydrogen atom transfer reactions mediated by alkyl radicals remain less-developed.A copper-catalyzed sulfone-induced regioselective C(sp^(3))—H bond heteroarylation reaction was reported.This strategy utilizes theα-alkyl radical of sulfone as an intramolecular hydrogen abstraction reagent,enabling the regioselective formation of carbon-nitrogen bonds under copper catalysis. 展开更多
关键词 radical reaction hydrogen atom transfer C—H bond functionalization heteroarylation
原文传递
Boosting bidirectional sulfur conversion enabled by introducing boron-doped atoms and phosphorus vacancies in Ni_(2)P for lithium-sulfur batteries 被引量:2
7
作者 Lin Peng Yu Bai +3 位作者 Hang Li Meixiu Qu Zhenhua Wang Kening Sun 《Journal of Energy Chemistry》 2025年第1期760-769,共10页
Lithium-sulfur (Li-S) batteries have gained great attention due to the high theoretical energy density and low cost,yet their further commercialization has been obstructed by the notorious shuttle effect and sluggish ... Lithium-sulfur (Li-S) batteries have gained great attention due to the high theoretical energy density and low cost,yet their further commercialization has been obstructed by the notorious shuttle effect and sluggish redox dynamics.Herein,we supply a strategy to optimize the electron structure of Ni_(2)P by concurrently introducing B-doped atoms and P vacancies in Ni_(2)P (Vp-B-Ni_(2)P),thereby enhancing the bidirectional sulfur conversion.The study indicates that the simultaneous introduction of B-doped atoms and P vacancies in Ni_(2)P causes the redistribution of electron around Ni atoms,bringing about the upward shift of d-band center of Ni atoms and effective d-p orbital hybridization between Ni atoms and sulfur species,thus strengthening the chemical anchoring for lithium polysulfides (LiPSs) as well as expediting the bidirectional conversion kinetics of sulfur species.Meanwhile,theoretical calculations reveal that the incorporation of B-doped atoms and P vacancies in Ni_(2)P selectively promotes Li2S dissolution and nucleation processes.Thus,the Li-S batteries with Vp-B-Ni_(2)P-separators present outstanding rate ability of 777 m A h g^(-1)at 5 C and high areal capacity of 8.03 mA h cm^(-2)under E/S of 5μL mg^(-1)and sulfur loading of 7.20 mg cm^(-2).This work elucidates that introducing heteroatom and vacancy in metal phosphide collaboratively regulates the electron structure to accelerate bidirectional sulfur conversion. 展开更多
关键词 B-doped atoms P vacancies Nickel phosphide Bidirectional sulfur conversion Lithium-sulfur batteries
在线阅读 下载PDF
Perspectives on metal-organic framework-derived microwave absorption materials 被引量:2
8
作者 Meng-Qi Wang Mao-Sheng Cao 《Journal of Materials Science & Technology》 2025年第11期37-52,共16页
Exploring efficient microwave absorbing materials(MAMs)has gradually become a hot topic in recent years because it is crucial in both civil and military fields.Metal-organic framework(MOF)has great potential due to it... Exploring efficient microwave absorbing materials(MAMs)has gradually become a hot topic in recent years because it is crucial in both civil and military fields.Metal-organic framework(MOF)has great potential due to its unique composition and bonding mode,which has advantages such as large specific surface area,high porosity,adjustable structure,and designable composition.Herein,MOF-derived MAMs are highlighted based on morphology and structure.The synthesis strategies of MOF-derived MAMs of different dimensions are discussed.On this basis,the structure-activity relationships can be deeply explored through the precise control of material structure and property by atomic engineering.Finally,perspectives are given for the existing problems of MOF-derived MAMs,which will open a new horizon and promote the development of MAMs. 展开更多
关键词 Metal-organic framework Atomic engineering Microwave absorption
原文传递
Biomass-derived single atom catalysts with phosphorus-coordinated Fe-N_(3)P configuration for efficient oxygen reduction reaction 被引量:2
9
作者 Peng-Peng Guo Abrar Qadir +6 位作者 Chao Xu Kun-Zu Yang Yong-Zhi Su Xin Liu Ping-Jie Wei Qinggang He Jin-Gang Liu 《Green Energy & Environment》 2025年第5期1064-1072,共9页
Exploiting non-precious metal catalysts with excellent oxygen reduction reaction(ORR)performance for energy devices is paramount essential for the green and sustainable society development.Herein,low-cost,high-perform... Exploiting non-precious metal catalysts with excellent oxygen reduction reaction(ORR)performance for energy devices is paramount essential for the green and sustainable society development.Herein,low-cost,high-performance biomass-derived ORR catalysts with an asymmetric Fe-N_(3)P configuration was prepared by a simple pyrolysis-etching technique,where carboxymethyl cellulose(CMC)was used as the carbon source,urea and 1,10-phenanthroline iron complex(FePhen)as additives,and Na_(3)PO_(4)as the phosphorus dopant and a pore-forming agent.The CMC-derived FeNPC catalyst displayed a large specific area(BET:1235 m^(2)g^(-1))with atomically dispersed Fe-N_(3)P active sites,which exhibited superior ORR activity and stability in alkaline solution(E_(1/2)=0.90 V vs.RHE)and Zn-air batteries(P_(max)=149 mW cm^(-2))to commercial Pt/C catalyst(E_(1/2)=0.87 V,P_(max)=118 mW cm^(-2))under similar experimental conditions.This work provides a feasible and costeffective route toward highly efficient ORR catalysts and their application to Zn-air batteries for energy conversion. 展开更多
关键词 Oxygen reduction reaction Biomass-derived electrocatalyst Single atom catalyst Phosphorus dopant Zn-air battery
在线阅读 下载PDF
Atomic-scale investigation on the evolution of T_(1) precipitates in an aged Al-Cu-Li-Mg-Ag alloy 被引量:1
10
作者 Xinyue Zhao Juan Ding +2 位作者 Daihong Xiao Lanping Huang Wensheng Liu 《Journal of Materials Science & Technology》 2025年第6期139-148,共10页
The T_(1)(Al_(2) CuLi)phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li.However,its formation and evolution still need to be further clarified during aging due to the compl... The T_(1)(Al_(2) CuLi)phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li.However,its formation and evolution still need to be further clarified during aging due to the complex precipitation sequences.Here,a detailed investigation has been carried out on the atomic struc-tural evolution of T_(1) precipitate in an aged Al-Cu-Li-Mg-Ag alloy using state-of-the-art Cs-corrected high-angle annular dark field(HAADF)-coupled with integrated differential phase contrast(iDPC)-scanning transmission electron microscopy(STEM)and energy-dispersive X-ray spectroscopy(EDXS)techniques.An intermediate T_(1)’phase between T_(1p) and T_(1) phase,with a crystal structure and orientation rela-tionship consistent with T_(1),but exhibiting different atomic occupancy and chemical composition was found.We observed the atomic structural transformation from T_(1p) to T_(1)’phase(fcc→hcp),involving only 1/12<112>Al shear component.DFT calculation results validated our proposed structural models and the precipitation sequence.Besides,the distributions of minor solute elements(Ag,Mg,and Zn)in the pre-cipitates exhibited significant differences.These findings may contribute to a further understanding of the nucleation mechanism of T_(1) precipitate. 展开更多
关键词 PRECIPITATE Chemical composition Atomic structure Aluminium alloy STEM
原文传递
Effects of pressure oscillations on impinging-jet atomization and spray combustion in liquid rocket engines 被引量:1
11
作者 Zhili PENG Bo ZHONG +1 位作者 Xiaodong CHEN Longfei LI 《Chinese Journal of Aeronautics》 2025年第4期25-43,共19页
Combustion dynamics are a critical factor in determining the performance and reliabilityof a chemical propulsion engine.The underlying processes include liquid atomization,evaporation,mixing,and chemical reactions.Thi... Combustion dynamics are a critical factor in determining the performance and reliabilityof a chemical propulsion engine.The underlying processes include liquid atomization,evaporation,mixing,and chemical reactions.This paper presents a high-fidelity numerical study of liquidatomization and spray combustion under high-pressure conditions,emphasizing the effects of pres-sure oscillations on the flow evolution and combustion dynamics.The theoretical framework isbased on the three-dimensional conservation equations for multiphase flows and turbulent combus-tion.The numerical solution is achieved using a coupling method of volume-of-fluid and Lagran-gian particle tracking.The Zhuang-Kadota-Sutton(ZKS)high-pressure evaporation model andthe eddy breakup-Arrhenius combustion model are employed.Simulations are conducted for amodel combustion chamber with impinging-jet injectors using liquid oxygen and kerosene as pro-pellants.Both conditions with and without inlet and outlet pressure oscillations are considered.Thefindings reveal that pressure oscillations amplify flow fluctuations and can be characterized usingkey physical parameters such as droplet evaporation,chemical reaction,and chamber pressure.The spectral analysis uncovers the axial variations of the dominant and secondary frequenciesand their amplitudes in terms of the characteristic physical quantities.This research helps establisha methodology for exploring the coupling effect of liquid atomization and spray combustion.It alsoprovides practical insights into their responses to pressure oscillations during the occurrence ofcombustion instability.This information can be used to enhance the design and operation ofliquid-fueled propulsion engines. 展开更多
关键词 Liquid atomization Spray combustion Pressure oscillations High-pressure evaporation Combustion instability
原文传递
Transition Metal Carbonitride MXenes Anchored with Pt Sub-Nanometer Clusters to Achieve High-Performance Hydrogen Evolution Reaction at All pH Range 被引量:1
12
作者 Zhihao Lei Sajjad Ali +18 位作者 CI Sathish MuhammadIbrar Ahmed Jiangtao Qu Rongkun Zheng Shibo Xi Xiaojiang Yu MBHBreese Chao Liu Jizhen Zhang Shuai Qi Xinwei Guan Vibin Perumalsamy Mohammed Fawaz Jae-Hun Yang Mohamed Bououdina Kazunari Domen Ajayan Vinu Liang Qiao Jiabao Yi 《Nano-Micro Letters》 2025年第5期525-539,共15页
Transition metal carbides,known as MXenes,particularly Ti_(3)C_(2)T_(x),have been extensively explored as promising materials for electrochemical reactions.However,transition metal carbonitride MXenes with high nitrog... Transition metal carbides,known as MXenes,particularly Ti_(3)C_(2)T_(x),have been extensively explored as promising materials for electrochemical reactions.However,transition metal carbonitride MXenes with high nitrogen content for electrochemical reactions are rarely reported.In this work,transition metal carbonitride MXenes incorporated with Pt-based electrocatalysts,ranging from single atoms to sub-nanometer dimensions,are explored for hydrogen evolution reaction(HER).The fabricated Pt clusters/MXene catalyst exhibits superior HER performance compared to the single-atom-incorporated MXene and commercial Pt/C catalyst in both acidic and alkaline electrolytes.The optimized sample shows low overpotentials of 28,65,and 154 mV at a current densities of 10,100,and 500 m A cm^(-2),a small Tafel slope of 29 m V dec^(-1),a high mass activity of 1203 mA mgPt^(-1)and an excellent turnover frequency of 6.1 s^(-1)in the acidic electrolyte.Density functional theory calculations indicate that this high performance can be attributed to the enhanced active sites,increased surface functional groups,faster charge transfer dynamics,and stronger electronic interaction between Pt and MXene,resulting in optimized hydrogen absorption/desorption toward better HER.This work demonstrates that MXenes with a high content of nitrogen may be promising candidates for various catalytic reactions by incorporating single atoms or clusters. 展开更多
关键词 MXene Hydrogen evolution reaction Single atom Two-dimensional nanosheets Density functional theory
在线阅读 下载PDF
High-voltage MIM-type aluminum electrolytic capacitors 被引量:1
13
作者 Yuan Guo Shixin Wang +5 位作者 Xianfeng Du Xinkuan Zang Zhongshuai Liang Jun Xiong Ruizhi Wang Zhuo Li 《Journal of Energy Chemistry》 2025年第5期79-90,共12页
Metal-insulator-metal aluminium electrolytic capacitors(MIM-AECs)combine high capacity-density and high breakdown field strength of solid AECs with high-frequency responsibility,wide workingtemperature window and wate... Metal-insulator-metal aluminium electrolytic capacitors(MIM-AECs)combine high capacity-density and high breakdown field strength of solid AECs with high-frequency responsibility,wide workingtemperature window and waterproof properties of MIM nanocapacitors.However,interfacial atomic diffusion poses a major obstacle,preventing the high-voltage MIM-AECs exploitation and thereby hampering their potential and advantages in high-power and high-energy-density applications.Here,an innovative high-voltage MIM-AECs were fabricated.The AlPO_(4)buffer layer is formed on AlO(OH)/AAO/Al surface by using H_(3)PO_(4)treatment,then a stable van der Waals(vdW)SnO_(2)/AlPO_(4)/AAO/Al multilayer was constructed via atomic layer deposition(ALD)technology.Due to higher diffusion barrier and lower carrier migration of SnO_(2)/AlPO_(4)/AAO interfaces,Sn atom diffusion is inhibited and carrier acceleration by electric field is weakened,guaranteeing high breakdown field strength of dielectric AAO and avoiding local breakdown risks.Through partial etching to hydrated AlO(OH)by H_(3)PO_(4)treatment,the tunnel was further opened up to facilitate subsequent ALD-SnO_(2)entry,thus obtaining a high SnO_(2)coverage.The SnO_(2)/AlPO_(4)/AAO/Al capacitors show a comprehensive performance in high-voltage(260 V),hightemperature(335℃),high-humidity(100%RH)and high-frequency response(100 k Hz),outperforming commercial solid-state AECs,and high-energy density(8.6μWh/cm^(2)),markedly exceeding previously reported MIM capacitors.The work lays the foundation for next-generation capacitors with highvoltage,high-frequency,high-temperature and high-humidity resistance. 展开更多
关键词 MIM nanocapacitor Electrolytic capacitor Buffer layer Atomic layer deposition High voltage
在线阅读 下载PDF
High-performance KNN-based piezoelectric ceramics for buzzer application 被引量:1
14
作者 Cheng Xiong Bosen Li +2 位作者 Zhongxin Liao Yan Qiu Daqiang Gao 《Chinese Physics B》 2025年第4期591-596,共6页
Piezoelectric ceramic materials are important components of piezoelectric buzzers,where the parameter of inverse piezoelectric coefficient(d_(33)^(*))plays a decisive role in the performance of the buzzer.Here,we repo... Piezoelectric ceramic materials are important components of piezoelectric buzzers,where the parameter of inverse piezoelectric coefficient(d_(33)^(*))plays a decisive role in the performance of the buzzer.Here,we report the manufacture and performance of a lead-free ceramic-based(0.96(K_(0.5)Na_(0.5))(Nb_(0.96)Sb_(0.04))O_(3)-0.04(Bi_(0.5)Na_(0.5))ZrO_(3)-1 mol%Al_(2)O_(3),abbreviated as KNNS-BNZ-1 mol%Al_(2)O_(3))piezoelectric buzzer and compare it with commercial(PbZr_(0.5)Ti_(0.5)O_(3),abbreviated as PZT)ceramics.Briefly,KNN-based ceramics have a typical perovskite structure and piezoelectric properties of d_(33)=480 pC/N,k_(p)=0.62 and d_(33)^(*)=830 pm/V,compared to d_(33)=500 pC/N,k_(p)=0.6 and d_(33)^(*)=918 pm/V of the commercial PZT-4 ceramics.Our results show that the KNNS-BNZ-1 mol%Al_(2)O_(3)ceramics have a similar sound pressure level performance over the testing frequency range to commercial PZT ceramics(which is even better in the 3-4 kHz range).These findings highlight the great application potential of KNN-based piezoelectric ceramics. 展开更多
关键词 lead-free piezoelectric ceramics phase structure engineering BUZZER ATOMIZER
原文传递
Nondestructive detection of atom counts in laser-trapped ^(171)Yb atoms 被引量:1
15
作者 Congcong Tian Qiang Zhu +4 位作者 Bing Wang Dezhi Xiong Zhuanxian Xiong Lingxiang He Baolong Lyu 《Chinese Physics B》 2025年第2期223-228,共6页
We present the experimental demonstration of nondestructive detection of ^(171)Yb atoms in a magneto-optical trap(MOT) based on phase shift measurement induced by the atoms on a weak off-resonant laser beam. After loa... We present the experimental demonstration of nondestructive detection of ^(171)Yb atoms in a magneto-optical trap(MOT) based on phase shift measurement induced by the atoms on a weak off-resonant laser beam. After loading a green MOT of ^(171)Yb atoms, the phase shift is obtained with a two-color Mach–Zehnder interferometer by means of ±45 MHz detuning with respect to the ^(1)S_(0)–^(1)P_(1) transition. We measured a phase shift of about 100 mrad corresponding to an atom count of around 5 × 10^(5). This demonstrates that it is possible to obtain the number of atoms without direct destructive measurement compared with the absorption imaging method. This scheme could be an important approach towards a high-precision lattice clock for clock operation through suppression of the impact of the Dick effect. 展开更多
关键词 ytterbium atoms Mach–Zehnder interferometer nondestructive detection phase shift
原文传递
Synergistically enhanced ORR and HER performance on Co-N-C coupled in-situ generated PtCo intermetallic 被引量:1
16
作者 Guanyu Luo Min Song +6 位作者 Lulu An Xiao Huang Qian Zhang Chenhao Zhang Tao Shen Shuang Wang Deli Wang 《Journal of Energy Chemistry》 2025年第1期721-729,共9页
Integrating multi-scale sites in a composite catalyst is vital to realize efficient electrocatalysis.Herein,a synergistic composite catalyst consisting of Co atomic sites and in-situ generated PtCo intermetallic compo... Integrating multi-scale sites in a composite catalyst is vital to realize efficient electrocatalysis.Herein,a synergistic composite catalyst consisting of Co atomic sites and in-situ generated PtCo intermetallic compounds (IMCs)(o-PtCo@CoNC) is proposed through Co pre-anchoring and subsequent impregnation-reduction method.High loading of Co atoms provides a chance for in-situ generating PtCo ordered intermetallic compounds.The remaining Co single atoms and PtCo IMCs construct synergistic electrocatalytic micro-regions.Benefiting from the ordered structure,synergistic effect of Pt Co IMCs and Co single atoms,o-PtCo@CoNC exhibits excellent electrocatalytic performance for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) with mass activity of 1.21 A mgPt-1(at 0.9 V) and5.70 A mgPt-1(at an overpotential of 100 mV),respectively.Besides,o-PtCo@CoNC delivers negligible loss of half-wave potential and overpotential during long-term stability test in acid solutions,with 13 mV decay after 50,000 potential cycles for ORR and a 2.7 mV decay after 20,000 potential cycles for HER.The integration strategy of single-atomic sites coupled IMCs paves the way for enhancing the activity and durability of Pt-based electrocatalysts. 展开更多
关键词 Synergistic effect INTERMETALLICS Single atomic sites Oxygen reduction reaction Hydrogen evolution reaction
在线阅读 下载PDF
Stable Cu(Ⅰ)single copper atoms supported on porous carbon nitride nanosheets for efficient photocatalytic degradation of antibiotics 被引量:1
17
作者 Xiao-Ye Xu Xiu-Hang Liu +7 位作者 Hui-Hui Gan Ding-Nan Lu Xiao-Meng Jiang Meng-Fei Yu Shuo Pan Jia-Yue Luo Hong-Li Sun Xue-Hua Zhang 《Rare Metals》 2025年第3期1756-1766,共11页
Exploration of stable metal single-site supported porous graphitic carbon nitride(PCN)nanostructures and the development of maximum atom utilization for enhanced photocatalytic oxidation of antibiotics remains a chall... Exploration of stable metal single-site supported porous graphitic carbon nitride(PCN)nanostructures and the development of maximum atom utilization for enhanced photocatalytic oxidation of antibiotics remains a challenge in current research.This work proposed a one-step thermal copolymerization to obtain Cu(Ⅰ)doping porous carbon nitride(CUCN)through a spontaneously reducing atmosphere by urea in a covered crucible.The obtained CUCN had crumpled ultrathin nanosheets and mesoporous structures,which possessed higher specific surface areas than PCN.From X-ray absorption near edge structure(XANES)and Fourier transform extended X-ray absorption fine structure(FT-EXAFS)spectra analysis,the Cu doping existed in the oxidation state of Cu(Ⅰ)as single atoms anchored on the 2D layers of CN through two N neighbors,thereby facilitating efficient pathways for the transfer of photoexcited charge carriers.Furthermore,the photoluminescence(PL)spectra,electrochemical impedance spectra(EIS)and transient photocurrent response test proved the improved separation and transfer of photoexcited charge carriers for Cu(Ⅰ)introduction.Consequently,the photocatalytic activity of CUCN was much better than that of PCN for antibiotics norfloxacin(NOR),with 4.7-fold higher degradation reaction rate constants.From species-trapping experiments and density function theory(DFT)calculations,the Cu single atoms in Cu-N_(2)served as catalytic sites that could accelerate charge transfer and facilitate the adsorption of molecular oxygen to produce active species.The stable Cu(Ⅰ)embedded in the layer structure led to the excellent recycling test and remained stable after four runs of degradation and even thermal regenerated treatment.The degradation paths of NOR by CUCN under visible light were also demonstrated.Our work sheds light on a sustainable and practical approach for achieving stable metal single-atom doping and enhancing photocatalytic degradation of aqueous pollutants. 展开更多
关键词 Graphitic carbon nitride Antibiotic degradation Cu single copper atom Active species Degradation pathways
原文传递
Exploring catalyst developments in heterogeneous CO_(2) hydrogenation to methanol and ethanol:A journey through reaction pathways 被引量:1
18
作者 Rasoul Salami Yimin Zeng +2 位作者 Xue Han Sohrab Rohani Ying Zheng 《Journal of Energy Chemistry》 2025年第2期345-384,I0008,共41页
The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation... The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation of CO_(2)to produce marketable carbon-based products like methanol and ethanol is a practical approach that offers great potential to reduce CO_(2)emissions.Although significant volumes of methanol are currently produced from CO_(2),developing highly efficient and stable catalysts is crucial for further enhancing conversion and selectivity,thereby reducing process costs.An in-depth examination of the differences and similarities in the reaction pathways for methanol and ethanol production highlights the key factors that drive C-C coupling.Identifying these factors guides us toward developing more effective catalysts for ethanol synthesis.In this paper,we explore how different catalysts,through the production of various intermediates,can initiate the synthesis of methanol or ethanol.The catalytic mechanisms proposed by spectroscopic techniques and theoretical calculations,including operando X-ray methods,FTIR analysis,and DFT calculations,are summarized and presented.The following discussion explores the structural properties and composition of catalysts that influence C-C coupling and optimize the conversion rate of CO_(2)into ethanol.Lastly,the review examines recent catalysts employed for selective methanol and ethanol production,focusing on single-atom catalysts. 展开更多
关键词 CO_(2)hydrogenation METHANOL ETHANOL Catalytic mechanism Operando techniques Single atom catalyst Tandem catalyst
在线阅读 下载PDF
Atomic surface of diamond induced by novel green photocatalytic chemical mechanical polishing with high material removal rate 被引量:1
19
作者 Zhibin Yu Zhenyu Zhang +6 位作者 Zinuo Zeng Cheng Fan Yang Gu Chunjing Shi Hongxiu Zhou Fanning Meng Junyuan Feng 《International Journal of Extreme Manufacturing》 2025年第2期661-676,共16页
Atomic surfaces are strictly required by high-performance devices of diamond.Nevertheless,diamond is the hardest material in nature,leading to the low material removal rate(MRR)and high surface roughness during machin... Atomic surfaces are strictly required by high-performance devices of diamond.Nevertheless,diamond is the hardest material in nature,leading to the low material removal rate(MRR)and high surface roughness during machining.Noxious slurries are widely used in conventional chemical mechanical polishing(CMP),resulting in the possible pollution to the environment.Moreover,the traditional slurries normally contain more than four ingredients,causing difficulties to control the process and quality of CMP.To solve these challenges,a novel green CMP for single crystal diamond was developed,consisting of only hydrogen peroxide,diamond abrasive and Prussian blue(PB)/titania catalyst.After CMP,atomic surface is achieved with surface roughness Sa of 0.079 nm,and the MRR is 1168 nm·h^(-1).Thickness of damaged layer is merely 0.66 nm confirmed by transmission electron microscopy(TEM).X-ray photoelectron spectroscopy,electron paramagnetic resonance and TEM reveal that·OH radicals form under ultraviolet irradiation on PB/titania catalyst.The·OH radicals oxidize diamond,transforming it from monocrystalline to amorphous atomic structure,generating a soft amorphous layer.This contributes the high MRR and formation of atomic surface on diamond.The developed novel green CMP offers new insights to achieve atomic surface of diamond for potential use in their high-performance devices. 展开更多
关键词 photocatalytic chemical mechanical polishing DIAMOND photocatalytic Fenton reaction material removal rate atomic diamond surface
在线阅读 下载PDF
Rare Earth Oxide Surface Modification of Porous SiO_(2) Film Prepared by Atomic Layer Deposition
20
作者 JIN Jianfei LÜLin +3 位作者 LI Ying YAN Lu CAO Yunzhen LI Wei 《无机材料学报》 北大核心 2025年第9期1029-1036,I0003,共9页
Broadband transparent films play a pivotal role in various applications such as lenses and solar cells,particularly porous structured transparent films exhibit significant potential.This study investigates a porous Si... Broadband transparent films play a pivotal role in various applications such as lenses and solar cells,particularly porous structured transparent films exhibit significant potential.This study investigates a porous SiO_(2) refractive index gradient anti-reflective film prepared by atomic layer deposition(ALD).A porous SiO_(2) film with gradual porosity was obtained by phosphoric acid etching of Al_(2)O_(3)/SiO_(2) multilayers with gradient Al2O3 ratios,achieving a gradual decrease in refractive index from the substrate to the surface.The film exhibited an average transmittance as high as 97.8%within the wavelength range from 320 nm to 1200 nm.The environmental adaptability was further enhanced by surface modification using rare earth oxide(REO)La_(2)O_(3),resulting in formation of a lotus leaf-like structure and achieving a water contact angle of 100.0°.These data proved that the modification significantly improved hydrophobic self-cleaning capability while maintaining exceptional transparency of the film.The surface structure of the modified film remained undamaged even after undergoing wipe testing,demonstrating its excellent surface durability. 展开更多
关键词 porous SiO_(2) rare earth oxide atomic layer deposition anti-reflective SELF-CLEANING
在线阅读 下载PDF
上一页 1 2 227 下一页 到第
使用帮助 返回顶部