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Ultra‑Efficient and Cost‑Effective Platinum Nanomembrane Electrocatalyst for Sustainable Hydrogen Production

Nano-Micro Letters 2024年第6期16卷 95-110页

作者： Xiang Gao Shicheng Dai Yun Teng Qing Wang Zhibo Zhang Ziyin Yang Minhyuk Park Hang Wang Zhe Jia Yunjiang Wang Yong Yang Department of Mechanical Engineering College of EngineeringCity University of Hong KongTat Chee AvenueKowloon TongKowloonHong KongPeople’s Republic of China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijingPeople’s Republic of China School of Engineering Science University of Chinese Academy of SciencesBeijingPeople’s Republic of China Laboratory for Microstructures Institute of MaterialsShanghai UniversityShanghaiPeople’s Republic of China School of Materials Science and Engineering Jiangsu Key Laboratory for Advanced Metallic MaterialsSoutheast UniversityNanjingPeople’s Republic of China Department of Materials Science and Engineering College of EngineeringCity University of Hong KongTat Chee AvenueKowloon TongKowloonHong KongPeople’s Republic of China

Hydrogen production through hydrogen evolution reaction(HER)offers a promising solution to combat climate change by replacing fossil fuels with clean energy ***,the widespread adoption of efficient electrocatalysts,such as platinum(Pt),has been hindered by their high *** this study,we developed an easy-to-implement method to create ultrathin Pt nanomembranes,which catalyze HER at a cost significantly lower than commercial Pt/C and comparable to non-noble metal *** Pt nanomembranes consist of highly distorted Pt nanocrystals and exhibit a heterogeneous elastic strain field,a characteristic rarely seen in conventional *** unique feature results in significantly higher electrocatalytic efficiency than various forms of Pt electrocatalysts,including Pt/C,Pt foils,and numerous Pt singleatom or single-cluster *** research offers a promising approach to develop highly efficient and cost-effective low-dimensional electrocatalysts for sustainable hydrogen production,potentially addressing the challenges posed by the climate crisis.

关键词： Platinum Hydrogen evolution reaction Lattice distortion Heterogeneous strain

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Mechanical and magneto-electronic properties of europium lanthanide-based cubic perovskites EuYO_(3)(Y=Cr, Mn, Fe): An ab initio study

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Journal of Rare Earths 2024年第3期42卷 562-569,I0005页

作者： Hayat Ullah Azra Sarwar Sajad Ali Rabah Khenata Abdelmadjid Bouhemadou Saad Bin-Omran Department of Physics Women University of Azad Jammu&Kashmir Bagh 10250Pakistan Department of Physics Abdul Wali Khan UniversityMardan23200KPPakistan LPQ3M Laboratory Institute of Science and TechnologyUniversity of Mascara29000MascaraAlgeria Laboratory for Developing New Materials and Their Characterization Farhat Abbas University Setif l19000SetifAlgeria Department of Physics and Astronomy College of ScienceKing Saud UniversityP.O.Box 2455Riyadh11451Saudi Arabia

Computational calculations using density functional theory(DFT) were performed for the first time using the full potential linearized augmented plane wave plus local orbital method(FP-LAPW + LO) to determine the structural, elastic, electronic and magnetic properties of europium-based cubic perovskites EuYO_(3)(Y=Cr, Mn, Fe). The exchange correlation potentials of GGA along with some analytical methods were adopted for the computation of structural and elastic properties. Moreover, the GGA + U formalism was also added for obtaining more precise electronic and magnetic properties, particularly to address the Eu-4f and Y-3d orientations in the spin-polarized double cell symmetry. The observed lattice parameters of these compounds are consistent with experiment. The observed bulk moduli predict that EuCrO_(3) is harder and less compressible than EuMnO_(3) and EuFeO_(3). The calculated tolerance factors of these compounds are within the cubic symmetry range. Our computed critical radius of EuCrO_(3) shows that EuCrO_(3) has a larger migration energy. Based on their elastic properties, these compounds are ductile in nature. We also computed the thermal properties of these compounds. The band structures and density of states show that these compounds are metallic in character. The lowest ground state energy and magnetic moments of these compounds expose their ferromagnetic nature. The metallic nature and strong ferromagnetism of these compounds make them promising applicants for application in spintronic.

关键词： Perovskites GGA+U Elastic constants Band structure Magnetic moments Rare earths

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Multimodal Dependence Attention and Large-Scale Data Based Offline Handwritten Formula Recognition

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Journal of Computer Science & Technology 2024年第3期39卷 654-670页

作者：刘汉超董兰芳张信明 School of Computer Science and Technology University of Science and Technology of ChinaHefei 230022China

Offline handwritten formula recognition is a challenging task due to the variety of handwritten symbols and two-dimensional formula ***,the deep neural network recognizers based on the encoder-decoder frame-work have achieved great improvements on this ***,the unsatisfactory recognition performance for formulas with long LTeX strings is one shortcoming of the existing ***,lacking sufficient training data also limits the capability of these *** this paper,we design a multimodal dependence attention(MDA)module to help the model learn visual and semantic dependencies among symbols in the same formula to improve the recognition perfor-mance of the formulas with long LTeX *** alleviate overfitting and further improve the recognition performance,we also propose a new dataset,Handwritten Formula Image Dataset(HFID),which contains 25620 handwritten formula images collected from real *** conduct extensive experiments to demonstrate the effectiveness of our proposed MDA module and HFID dataset and achieve state-of-the-art performances,63.79%and 65.24%expression accuracy on CROHME 2014 and CROHME 2016,respectively.

关键词： handwritten formula recognition multimodal dependence attention semantic dependence visual dependence Handwritten Formula Image Dataset

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Improving chitosan-based composite membrane by introducing a novel hybrid functional nano-hydroxyapatite with carboxymethyl cellulose and phytic acid

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Frontiers of Chemical Science and Engineering 2024年第6期18卷 1-15页

作者： Liuyun Jiang Yingjun Ma Shuo Tang Yuqing Wang Yan Zhang Shengpei Su Xiang Hu Jun He National&Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources Key Laboratory of Chemical Biology&Traditional Chinese Medicine Research(Ministry of Education)College of Chemistry and Chemical EngineeringHunan Normal UniversityChangsha 410081China State Key Laboratory Developmental Biology of Freshwater Fish School of Life ScienceHunan Normal UniversityChangsha 410081China Hunan Provincial Key Laboratory of Regional Hereditary Birth Defects Prevention and Control Changsha Hospital for Matemal&Child Health Care Aiffiliated to Hunan Normal UniversityChangsha 410081China

A functional hybrid nano-hydroxyapatite(carboxymethyl cellulose-phytic acid-n-HA,CMC-PA-n-HA)was prepared by adding CMC and *** results of Fourier transformation infrared spectra,X-ray diffraction,thermal gravimetric analysis and dispersion experiments indicated that the addition of CMC and PA affected the morphology,crystallinity and crystal size of hybrid n-HA,and CMC endowed hybrid n-HA with excellent *** electron microscope results showed that CMC-PA-n-HA nanoparticle could be uniformly dispersed in chitosan(CS)matrix to obtain composite membrane by casting technology,so that the highest tensile strength of CMC-PA-n-HA/CS composite membrane was 69.64%and 144.45%higher than that of CS membrane and n-HA/CS composite membrane,*** angle test showed that CMC-PA-n-HA effectively improved hydrophilicity of the CS *** simulated body fluid immersion results indicated that the CMC-PA-n-HA/CS composite membrane not only exhibited good degradability but also promoted bone-like apatite *** cell proliferation experiments proved that the introduction of PA made the composite membrane have better cell adhesion and proliferation *** tests demonstrated that PA could effectively improve the antibacterial properties of the composite membrane,which is expected to be applied as guide bone tissue regeneration membrane.

关键词： nano-hydroxyapatite chitosan dispersion guide bone tissue regeneration membrane

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Bivariate attribution of the compound hot and dry summer of 2022 on the Tibetan Plateau

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Science China Earth Sciences 2024年第7期67卷 2122-2136页

作者： Baiquan ZHOU Panmao ZHAI Zhen LIAO State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081China

The extraordinarily high temperatures experienced during the summer of 2022 on the Tibetan Plateau(TP)demand attention when compared with its typical climatic *** absence of precipitation alongside the elevated temperatures resulted in 2022 being the hottest and driest summer on record on the TP since at least *** the susceptibility of the TP to climate change,this study employed large-ensemble simulations from the HadGEM3-A-N216 attribution system,together with a copula-based joint probability distribution,to investigate the influence of anthropogenic forcing,primarily global greenhouse gas emissions,on this unprecedented compound hot and dry event(CHDE).Findings revealed that the return period for the 2022 CHDE on the TP exceeds 4000 years,as determined from the fitted joint distributions derived using observational data spanning *** CHDE was directly linked to large-scale circulation anomalies,including the control of equivalent-barotropic high-pressure anomalies and the northward displacement of the subtropical westerly jet ***,anthropogenic forcing has,to some extent,promoted the surface warming and increased variability in precipitation on the TP in summer,establishing conditions conducive for the 2022 CHDE from a long-term climate change *** return period for a 2022-like CHDE on the TP was estimated to be approximately 283 years(142-613 years)by the large ensemble forced by both anthropogenic activities and natural ***,ensemble simulations driven solely by natural forcing indicated that the likelihood of occurrence of a 2022-like CHDE was almost *** outcomes underscore that the contribution of anthropogenic forcing to the probability of a 2022-like CHDE was 100%,implying that without anthropogenically induced global warming,a comparable CHDE akin to that observed in 2022 on the TP would not be possible.

关键词： Compound hot and dry event Tibetan Plateau Bivariate event attribution Anthropogenic forcing

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Transfer of Highest Weight Modules and Small Unipotent Representations

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Acta Mathematica Sinica,English Series 2024年第3期40卷 772-791页

作者： Hai An HE Jing Song HUANG Kayue Daniel WONG Department of Mathematics College of SciencesShanghai UniversityShanghai 200444P.R.China Newtouch Center for Mathematics of Shanghai University Shanghai 200444P.R.China Mathematics research Center School of Science and EngineeringThe Chinese University of Hong KongShenzhen 518172P.R.China

We study the transfer between small special unipotent representations for all equal rank real forms of type E_(6) and E_(7). As a consequence, one can verify these modules are unitarity using the results of Wallach an... 详细信息

关键词： Unipotent representations Wallach representations Transfer of unitary modules

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Exploring the ultrahigh rolling contact fatigue life of M50 bearing steel by adjusting the cryogenic sequence

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Journal of Materials Science & Technology 2024年第2期169卷 243-250页

作者： Xin Cai Xiaoqiang Hu Xingyu Lu Hongwei Liu Yanfei Cao Dianzhong Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The influence of different cryogenic sequences on the rolling contact fatigue(RCF)life of M50-bearing steel has been *** results show that direct cryogenic treatment after quenching can effectively improve RCF *** L_(10)life is strikingly 5 times longer than that with cryogenic treatment after *** is caused by the distinct lattice construction of martensite and the transformation of retained *** secondary nanocarbides and fine twins are formed via cryogenic treatment before tem-pering compared with cryogenic treatment after *** improvement in the RCF life of the steel is attributed to the joint effects of the secondary nanocarbides and twin boundaries with a width of 5-13 nm,which delays significantly crack initiation and *** study highlights a common method to improve the service life of high-carbon and high-alloy steels by adjusting the cryogenic se-quence.

关键词： M50 steel Cryogenic treatment Rolling contact fatigue life Carbide Twin

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Topological edge and corner states of valley photonic crystals with zipper-like boundary conditions

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Chinese Physics B 2024年第4期33卷 480-491页

作者：沈云峰许孝芳孙铭周文佶常雅箐 School of Mechanical Engineering Jiangsu UniversityZhenjiang 212000China School of Optical and Electronic Information Suzhou City University&Suzhou Key Laboratory of BiophotonicsSuzhou 215104China

We present a stable valley photonic crystal(VPC)unit cell with C_(3v)symmetric quasi-ring-shaped dielectric columns and realize its topological phase transition by breaking mirror *** on this unit cell structure,topological edge states(TESs)and topological corner states(TCSs)are *** obtain a new type of wave transmission mode based on photonic crystal zipper-like boundaries and apply it to a beam splitter assembled from rectangular photonic crystals(PCs).The constructed beam splitter structure is compact and possesses frequency separation *** addition,we construct a box-shaped triangular PC structures with zipper-like boundaries and discover phenomena of TCSs in the corners,comparing its corner states with those formed by other *** on this,we explore the regularities of the electric field patterns of TESs and TCSs,explain the connection between the characteristic frequencies and locality of TCSs,which helps better control photons and ensures low power consumption of the system.

关键词： valley photonic crystal topological edge states topological corner states higher-order topological insulators topological phase transition

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Current-Induced Magnetization Switching Behavior in Perpendicular Magnetized L1_(0)-MnAl/B2-CoGa Bilayer

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Chinese Physics Letters 2024年第5期41卷 138-143页

作者：孙宏利韩荣坤秦红蕊赵旭鹏谢志成魏大海赵建华 State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100190China International School of Microelectronics Dongguan University of TechnologyDongguan 523808China

Rare-earth-free Mn-based binary alloy L1_(0)-MnAl with bulk perpendicular magnetic anisotropy(PMA) holds promise for high-performance magnetic random access memory(MRAM) devices driven by spin-orbit torque(SOT). However, the lattice-mismatch issue makes it challenging to place conventional spin current sources, such as heavy metals, between L1_(0)-MnAl layers and substrates. In this work, we propose a solution by using the B2-CoGa alloy as the spin current source. The lattice-matching enables high-quality epitaxial growth of 2-nm-thick L1_(0)-MnAl on B2-CoGa, and the L1_(0)-MnAl exhibits a large PMA constant of 1.04 × 10^(6)J/m^(3). Subsequently, the considerable spin Hall effect in B2-CoGa enables the achievement of SOT-induced deterministic magnetization switching. Moreover, we quantitatively determine the SOT efficiency in the bilayer. Furthermore, we design an L1_(0)-MnAl/B2-CoGa/Co_(2)MnGa structure to achieve field-free magnetic switching. Our results provide valuable insights for achieving high-performance SOT-MRAM devices based on L1_(0)-MnAl alloy.

关键词： alloy enable holds

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Nonexistence of quantum black and white hole horizons in an improved dynamic approach

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 56-73页

作者： Wen-Cong Gan Xiao-Mei Kuang Zhen-Hao Yang Yungui Gong Anzhong Wang Bin Wang College of Physics and Communication Electronics Jiangxi Normal UniversityNanchang 330022China GCAP-CASPER Physics DepartmentBaylor UniversityWaco 76798-7316USA Institute for Theoretical Physics&Cosmology Zhejiang University of TechnologyHangzhou 310023China United Center for Gravitational Wave Physics(UCGWP) Zhejiang University of TechnologyHangzhou 310023China Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China Department of Physics School of Physical Science and TechnologyNingbo UniversityNingbo 315211China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China

In this paper,we study the quantum geometric effects near the locations where classical black hole horizons used to appear in Einstein's classical theory,within the framework of an improved dynamic approach,in which the internal region of a black hole is modeled by the Kantowski-Sachs(KS)spacetime and the two polymerization parameters are functions of the phase space *** detailed analysis shows that the effects are so strong that black and white hole horizons of the effective quantum theory do not exist at all and instead are replaced by transition surfaces,across which the metric coefficients and their inverses are smooth and remain finite,as are the corresponding curvatures,including the Kretschmann *** surfaces always separate trapped regions from anti-trapped *** number of such surfaces is infinite,so the corresponding KS spacetimes become geodesically complete,and no black and white hole-like structures exist in this scheme.

关键词： canonical quantization loop quantum gravity quantum aspects of black holes

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