A modified electrolyte （CH3COOH-HClO4-A-B） for electropolishing （EP） of NiTi was presented for improving the corrosion resistance and biocompatibility of the alloy. Using the proposed parameters, a homogeneous and...A modified electrolyte （CH3COOH-HClO4-A-B） for electropolishing （EP） of NiTi was presented for improving the corrosion resistance and biocompatibility of the alloy. Using the proposed parameters, a homogeneous and uniform surface was obtained. Atomic force microscopy （AFM） revealed that the surface roughness （Ra） for EP sample （23.21 nm） was close to mechanical polishing （MP） sample （19.36 nm）. Analysis by X-ray photoelectron spectroscopy （XPS） showed that Ti/Ni ratio increased from 3.1 for MP sample to 27.6 for EP sample. Measurements using potentiodynamic polarization in Hanks＇ solution showed that no pitting occurred for EP sample even though the applied potential increased up to 1500 mV （vs SCE）, while the MP sample was broken down at 650 mV. The present study indicates that electropolishing NiTi with this modified electrolyte contributes to the improved biocompatibility of NiTi.展开更多
An effective and simple design method for co-continuous composite material construction is proposed by using a hybrid methodology with triply periodic minimal surface( TPMS) cellular topology and the volumetric distan...An effective and simple design method for co-continuous composite material construction is proposed by using a hybrid methodology with triply periodic minimal surface( TPMS) cellular topology and the volumetric distance field( VDF). After generating a set of VDF-based features for the given exterior shape and desired internal core structure,a series of simple modifications in distance fields enabled us to obtain an arbitrarily-shaped complex co-continuous composite material computational model. Design results and manufactured prototypes through 3 D printing technology show that the proposed methodology has the potential to open a new paradigm for producing multifunctional next generation co-continuous composite materials which are impossible to design and manufacture using traditional CAD and CAM.展开更多
This paper studies the most similar maximal clique query(MSMCQ).Given a graph G and a set of nodes Q,MSMCQ is to find the maximal clique of G having the largest similarity with Q.MSMCQ has many real applications inclu...This paper studies the most similar maximal clique query(MSMCQ).Given a graph G and a set of nodes Q,MSMCQ is to find the maximal clique of G having the largest similarity with Q.MSMCQ has many real applications including advertising industry,public security,task crowdsourcing and social network,etc.MSMCQ can be studied as a special case of the general set similarity query(SSQ).However,the MCs of G has several specialties from the general sets.Based on the specialties of MCs,we propose a novel index,namely MCIndex.MCIndex outperforms the state-of-the-art SSQ method significantly in terms of the number of candidates and the query time.Specifically,we first construct an inverted indexⅠfor all the MCs of G.Since the MCs in a posting list often have a lot of overlaps,MCIndex selects some pivots to cluster the MCs with a small radius.Given a query Q,we compute the distance from the pivots to Q.The clusters of the pivots assured not answer can be pruned by our distance based pruning rule.Since it is NP-hard to construct a minimum MCIndex,we propose to construct a minimal MCIndex onⅠ(v)with an approximation ratio 1+ln|Ⅰ(v)|.Since the MCs have properties that are inherent of graph structure,we further propose a S Index within each cluster of a MCIndex and a structure based pruning rule.S Index can significantly reduce the number of candidates.Since the sizes of intersections between Q and many MCs need to be computed during the query evaluation,we also propose a binary representation of MCs to improve the efficiency of the intersection size computation.Our extensive experiments confirm the effectiveness and efficiency of our proposed techniques on several real-world datasets.展开更多
High-entropy alloys(HEAs)are a promising solution for large-scale hydrogen storage(H-storage)and are therefore receiving increasing attention from the materials science community.In this study,we systematically invest...High-entropy alloys(HEAs)are a promising solution for large-scale hydrogen storage(H-storage)and are therefore receiving increasing attention from the materials science community.In this study,we systematically investigated the microstructures and H-storage properties of V_(35)Ti_(35)Cr_(10) Fe_(10)M_(10)(M=Mn,Co,Sc,or Ni)HEAs prepared by arcmelting.The cast HEAs were found to be nanocrystalline.The crystal lattice parameters and hydrogen absorption energies of the alloys were calculated using density functional theory(DFT)calculations.The alloys can be fully activated in just one cycle of hydrogen absorption/desorption under mild conditions,after which they reach hydrogen absorption saturation in approximately 100 s at ambient temperature.The hydrogenation kinetics of the HEAs are approximately five times higher than that of conventional solid-solution alloys with a body-centered cubic(BCC)structure.By performing in-situ hydriding differential scanning calorimetry in combination with DFT calculations,we revealed that the alloys are more susceptible to hydrogenation than traditional BCC structural alloys.The H-storage capacity of V_(35)Ti_(35)Cr_(10) Fe_(10)M_(10) alloys at ambient temperature was higher than that of HEAs reported in the literature.Quasi-in-situ X-ray diffraction characterization of the HEAs’hydrogenation revealed a phase transition process from a BCC to facecentered cubic,passing through a pseudo-BCC structure.Our work introduces a new perspective for designing alloys with ultrafast hydrogen absorption kinetics and high capacity for large-scale,room-temperature-applicable H-storage.展开更多
文摘A modified electrolyte （CH3COOH-HClO4-A-B） for electropolishing （EP） of NiTi was presented for improving the corrosion resistance and biocompatibility of the alloy. Using the proposed parameters, a homogeneous and uniform surface was obtained. Atomic force microscopy （AFM） revealed that the surface roughness （Ra） for EP sample （23.21 nm） was close to mechanical polishing （MP） sample （19.36 nm）. Analysis by X-ray photoelectron spectroscopy （XPS） showed that Ti/Ni ratio increased from 3.1 for MP sample to 27.6 for EP sample. Measurements using potentiodynamic polarization in Hanks＇ solution showed that no pitting occurred for EP sample even though the applied potential increased up to 1500 mV （vs SCE）, while the MP sample was broken down at 650 mV. The present study indicates that electropolishing NiTi with this modified electrolyte contributes to the improved biocompatibility of NiTi.
基金Sponsored by the Scientific Research Foundation of the Higher Education Institutions of Hainan Province of China(Grant No.Hnky2018-101)
文摘An effective and simple design method for co-continuous composite material construction is proposed by using a hybrid methodology with triply periodic minimal surface( TPMS) cellular topology and the volumetric distance field( VDF). After generating a set of VDF-based features for the given exterior shape and desired internal core structure,a series of simple modifications in distance fields enabled us to obtain an arbitrarily-shaped complex co-continuous composite material computational model. Design results and manufactured prototypes through 3 D printing technology show that the proposed methodology has the potential to open a new paradigm for producing multifunctional next generation co-continuous composite materials which are impossible to design and manufacture using traditional CAD and CAM.
基金support of NSF of China(61502258,61806105)Major Technology Innovation Project of Shandong(2018CXGC0703)+2 种基金NSF of Shandong Province(ZR2014FQ007)the Project of Shandong Finance Society(2018SDJR31)Soft Science Fund of Shandong Province(2018RKB01373,2016RKB01043).
文摘This paper studies the most similar maximal clique query(MSMCQ).Given a graph G and a set of nodes Q,MSMCQ is to find the maximal clique of G having the largest similarity with Q.MSMCQ has many real applications including advertising industry,public security,task crowdsourcing and social network,etc.MSMCQ can be studied as a special case of the general set similarity query(SSQ).However,the MCs of G has several specialties from the general sets.Based on the specialties of MCs,we propose a novel index,namely MCIndex.MCIndex outperforms the state-of-the-art SSQ method significantly in terms of the number of candidates and the query time.Specifically,we first construct an inverted indexⅠfor all the MCs of G.Since the MCs in a posting list often have a lot of overlaps,MCIndex selects some pivots to cluster the MCs with a small radius.Given a query Q,we compute the distance from the pivots to Q.The clusters of the pivots assured not answer can be pruned by our distance based pruning rule.Since it is NP-hard to construct a minimum MCIndex,we propose to construct a minimal MCIndex onⅠ(v)with an approximation ratio 1+ln|Ⅰ(v)|.Since the MCs have properties that are inherent of graph structure,we further propose a S Index within each cluster of a MCIndex and a structure based pruning rule.S Index can significantly reduce the number of candidates.Since the sizes of intersections between Q and many MCs need to be computed during the query evaluation,we also propose a binary representation of MCs to improve the efficiency of the intersection size computation.Our extensive experiments confirm the effectiveness and efficiency of our proposed techniques on several real-world datasets.
基金supported by the Natural Science Foundation of Inner Mongolia,China(grant nos.2022MS05011,2020LH01006,and 2022FX02)the National Natural Science Foundation of China(grant nos.52261041 and 51961032)+1 种基金the Major Science and Technology Project of Inner Mongolia(grant no.2021ZD0029)the Fundamental Research Funds for Inner Mongolia University of Science&Technology(grant no.2023QNJS119).
文摘High-entropy alloys(HEAs)are a promising solution for large-scale hydrogen storage(H-storage)and are therefore receiving increasing attention from the materials science community.In this study,we systematically investigated the microstructures and H-storage properties of V_(35)Ti_(35)Cr_(10) Fe_(10)M_(10)(M=Mn,Co,Sc,or Ni)HEAs prepared by arcmelting.The cast HEAs were found to be nanocrystalline.The crystal lattice parameters and hydrogen absorption energies of the alloys were calculated using density functional theory(DFT)calculations.The alloys can be fully activated in just one cycle of hydrogen absorption/desorption under mild conditions,after which they reach hydrogen absorption saturation in approximately 100 s at ambient temperature.The hydrogenation kinetics of the HEAs are approximately five times higher than that of conventional solid-solution alloys with a body-centered cubic(BCC)structure.By performing in-situ hydriding differential scanning calorimetry in combination with DFT calculations,we revealed that the alloys are more susceptible to hydrogenation than traditional BCC structural alloys.The H-storage capacity of V_(35)Ti_(35)Cr_(10) Fe_(10)M_(10) alloys at ambient temperature was higher than that of HEAs reported in the literature.Quasi-in-situ X-ray diffraction characterization of the HEAs’hydrogenation revealed a phase transition process from a BCC to facecentered cubic,passing through a pseudo-BCC structure.Our work introduces a new perspective for designing alloys with ultrafast hydrogen absorption kinetics and high capacity for large-scale,room-temperature-applicable H-storage.
