Owing to the unique structural,electronic,and physico-chemical properties,molybdenum clusters are expected to play an important role in future nanotechnologies.However,their ground states are still under debate.In thi...Owing to the unique structural,electronic,and physico-chemical properties,molybdenum clusters are expected to play an important role in future nanotechnologies.However,their ground states are still under debate.In this study,the crystal structure analysis by particle swarm optimization(CALYPSO)approach is used for the global minimum search,which is followed by first-principles calculations,to detect an obvious dimerization tendency in Mo_(n)(n=2-18)clusters when the 4s and 4p semicore states are not regarded as the valence states.Further,the clusters with even number of atoms are usually magic clusters with high stability.However,after including the4 s and 4 p electrons as valence electrons,the dimerization tendency exhibits a drastic reduction because the average hybridization indices H_(sp),H_(sd),and H_(pd) are reduced significantly.Overall,this work reports new ground states of Mo_(n)(n=11,14,15)clusters and proves that semicore states are essential for Mo_(n) clusters.展开更多
A novel electrochemical non-enzymatic glucose sensor based on three-dimensional Au/MXene nanocomposites was developed.MXenes were prepared using the mild etched method,and the porous foam of Au nanoparticles was combi...A novel electrochemical non-enzymatic glucose sensor based on three-dimensional Au/MXene nanocomposites was developed.MXenes were prepared using the mild etched method,and the porous foam of Au nanoparticles was combined with the MXene by means of in situ synthesis.By controlling the mass of MXene in the synthesis process,porous foam with Au nanoparticles was obtained.The three-dimensional foam structure of nanoparticles was confirmed by scanning electron microscopy.Cyclic voltammetry and electrochemical impedance spectroscopy were used to study the electrochemical performance of the Au/MXene nanocomposites.The Au/MXene nanocomposites acted as a fast redox probe for nonenzymatic glucose oxidation and showed good performance,including a high sensitivity of 22.45μA·(mmol/L)^(-1)·cm^(-1)and a wide linear range of 1-12 mmol/L.Studies have shown that MXene as a catalyst-supported material is beneficial to enhance the conductivity of electrons and increase the loading rate of the catalyst materials.The foam structure with Au nanoparticles can provide a larger surface area,increase the contact area with the molecule in the catalytic reaction,and enhance the electrochemical reaction signal.In summary,this study shows that Au/MXene nanoparticles have the potential to be used in non-enzymatic glucose sensors.展开更多
Up to now,at least 806 carbon allotropes have been proposed theoretically.Three interesting carbon allotropes(named Pbam-32,P6/mmm,and I43d)were recently uncovered based on a random sampling strategy combined with spa...Up to now,at least 806 carbon allotropes have been proposed theoretically.Three interesting carbon allotropes(named Pbam-32,P6/mmm,and I43d)were recently uncovered based on a random sampling strategy combined with space group and graph theory.The calculation results show that they are superhard and remarkably stable compared with previously proposed metastable phases.This indicates that they are likely to be synthesized in experiment.We use the factor group analysis method to analyze theirΓ-point vibrational modes.Owing to their large number of atoms in primitive unit cells(32 atoms in Pbam-32,36 atoms in P6/mmm,and 94 atoms in I43d),they have many Raman-and infrared-active modes.There are 48 Raman-active modes and 37 infrared-active modes in Pbam-32,24 Raman-active modes and 14 infrared-active modes in P6/mmm,and 34 Raman-active modes and 35 Raman-and infrared-active modes in I43d.Their calculated Raman spectra can be divided into middle frequency range from 600 cm-1 to 1150 cm-1 and high frequency range above 1150 cm-1.Their largest infrared intensities are 0.82,0.77,and 0.70(D/Å)2/amu for Pbam,P6/mmm,and I43d,respectively.Our calculated results provide an insight into the lattice vibrational spectra of these sp3 carbon allotropes and suggest that the middle frequency Raman shift and infrared spectrum may play a key role in identifying newly proposed carbon allotropes.展开更多
A fault-tolerant circuit is required for robust quantum computing in the presence of noise.Clifford+T circuits are widely used in fault-tolerant implementations.As a result,reducing T-depth,T-count,and circuit width h...A fault-tolerant circuit is required for robust quantum computing in the presence of noise.Clifford+T circuits are widely used in fault-tolerant implementations.As a result,reducing T-depth,T-count,and circuit width has emerged as important optimization goals.A measure-and-fixup approach yields the best T-count for arithmetic operations,but it requires quantum measurements.This paper proposes approximate Toffoli,TR,Peres,and Fredkin gates with optimized T-depth and T-count.Following that,we implement basic arithmetic operations such as quantum modular adder and subtractor using approximate gates that do not require quantum measurements.Then,taking into account the circuit width,T-depth,and T-count,we design and optimize the circuits of two multipliers and a divider.According to the comparative analysis,the proposed multiplier and divider circuits have lower circuit width,T-depth,and T-count than the current works that do not use the measure-and-fixup approach.Significantly,the proposed second multiplier produces approximately 77%T-depth,60%T-count,and 25%width reductions when compared to the existing multipliers without quantum measurements.展开更多
Object representation based on local features is a topical subject in the domain of image understanding and computer vision. We discuss the defects of global features in present methods and the advantages of local fea...Object representation based on local features is a topical subject in the domain of image understanding and computer vision. We discuss the defects of global features in present methods and the advantages of local features in object recognition, and briefly explore state-of-the-art recognition methods using local features, especially the main approaches of local feature extraction and object representation. To clearly explain these methods, the problem of local feature extraction is divided into feature region detection, feature region description, and feature space optimization. The main components and merits of these steps are presented. Technologies for object presentation are classified into three types: vector space, sliding window, and structure relationship models. Future development trends are discussed briefly.展开更多
Efficient quantum circuits for arithmetic operations are vital for quantum algorithms.A fault-tolerant circuit is required for a robust quantum computing in the presence of noise.Quantum circuits based on Clifford+T g...Efficient quantum circuits for arithmetic operations are vital for quantum algorithms.A fault-tolerant circuit is required for a robust quantum computing in the presence of noise.Quantum circuits based on Clifford+T gates are easily rendered faulttolerant.Therefore,reducing the T-depth and T-Count without increasing the qubit number represents vital optimization goals for quantum circuits.In this study,we propose the fault-tolerant implementations for TR and Peres gates with optimized T-depth and T-Count.Next,we design fault-tolerant circuits for quantum arithmetic operations using the TR and Peres gates.Then,we implement cyclic and complete translations of quantum images using quantum arithmetic operations,and the scalar matrix multiplication.Comparative analysis and simulation results reveal that the proposed arithmetic and image operations are efficient.For instance,cyclic translations of a quantum image produce 50%T-depth reduction relative to the previous best-known cyclic translation.展开更多
The precise mechanism of bone regeneration in different bone graft substitutes has been well studied in recent researches. However, miRNAs regulation of the bone formation has been always mysterious. We developed the ...The precise mechanism of bone regeneration in different bone graft substitutes has been well studied in recent researches. However, miRNAs regulation of the bone formation has been always mysterious. We developed the anterior lumbar interbody fusion (ALIF) model in pigs using equine bone protein extract (BPE), recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge (ACS), and autograft as bone graft substitute, respectively. The miRNA and gene expression profiles of different bone graft materials were examined using microarray technology and data analysis, including self-organizing maps, KEGG pathway and Biological process GO analyses. We then jointly analyzed miRNA and mRNA profiles of the bone fusion tissue at different time points respectively. Results showed that miRNAs, including let-7, miR-129, m iR-21, miR-133, miR-140, miR-146, miR-184, and miR-224, were involved in the regulation of the immune and inflammation response, which provided suitable inflammatory microenvironment for bone formation. At late stage, several miRNAs directly regulate SMAD4, Estrogen receptor 1 and 5-hydroxytryptamine (serotonin) receptor 2C for bone formation. It can be concluded that miRNAs play important roles in balancing the inflammation and bone formation.展开更多
This paper presents a novel algorithm for automatically detecting global shakiness in casual videos. Per-frame amplitude is computed by the geometry of motion, based on the kinematic model defined by inter-frame geome...This paper presents a novel algorithm for automatically detecting global shakiness in casual videos. Per-frame amplitude is computed by the geometry of motion, based on the kinematic model defined by inter-frame geometric transformations. Inspired by motion perception, we investigate the just-noticeable amplitude of shaky motion perceived by the human visual system. Then, we use the thresholding contrast strategy on the statistics of per-frame amplitudes to determine the occurrence of perceived shakiness. For testing the detection accuracy, a dataset of video clips is constructed with manual shakiness label as the ground truth. The experiments demonstrate that our algorithm can obtain good detection accuracy that is in concordance with subjective judgement on the videos in the dataset.展开更多
基金supported by the National Natural Science Foundation of China (No.11404098 and No.11604082)the Student Research Training Program of Henan University of Science and Technology(WLSRTP201911)
文摘Owing to the unique structural,electronic,and physico-chemical properties,molybdenum clusters are expected to play an important role in future nanotechnologies.However,their ground states are still under debate.In this study,the crystal structure analysis by particle swarm optimization(CALYPSO)approach is used for the global minimum search,which is followed by first-principles calculations,to detect an obvious dimerization tendency in Mo_(n)(n=2-18)clusters when the 4s and 4p semicore states are not regarded as the valence states.Further,the clusters with even number of atoms are usually magic clusters with high stability.However,after including the4 s and 4 p electrons as valence electrons,the dimerization tendency exhibits a drastic reduction because the average hybridization indices H_(sp),H_(sd),and H_(pd) are reduced significantly.Overall,this work reports new ground states of Mo_(n)(n=11,14,15)clusters and proves that semicore states are essential for Mo_(n) clusters.
基金supported by the National Natural Science Foundation of China(No.61704035)the Natural Science Foundation of Guangxi Province(2017GXNSFBA198125)Scientific Research and Technology Development Program of Guangxi(AD19110076,AD19110063)。
文摘A novel electrochemical non-enzymatic glucose sensor based on three-dimensional Au/MXene nanocomposites was developed.MXenes were prepared using the mild etched method,and the porous foam of Au nanoparticles was combined with the MXene by means of in situ synthesis.By controlling the mass of MXene in the synthesis process,porous foam with Au nanoparticles was obtained.The three-dimensional foam structure of nanoparticles was confirmed by scanning electron microscopy.Cyclic voltammetry and electrochemical impedance spectroscopy were used to study the electrochemical performance of the Au/MXene nanocomposites.The Au/MXene nanocomposites acted as a fast redox probe for nonenzymatic glucose oxidation and showed good performance,including a high sensitivity of 22.45μA·(mmol/L)^(-1)·cm^(-1)and a wide linear range of 1-12 mmol/L.Studies have shown that MXene as a catalyst-supported material is beneficial to enhance the conductivity of electrons and increase the loading rate of the catalyst materials.The foam structure with Au nanoparticles can provide a larger surface area,increase the contact area with the molecule in the catalytic reaction,and enhance the electrochemical reaction signal.In summary,this study shows that Au/MXene nanoparticles have the potential to be used in non-enzymatic glucose sensors.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1404111,11504089,61874160,61675064,and 11404098)the Fund for Young Key Teacher of Henan Province,China(Grant No.2016GGJS-059)the Henan Provincial Major Scientific and Technological Projects,China(Grant No.182102210289).
文摘Up to now,at least 806 carbon allotropes have been proposed theoretically.Three interesting carbon allotropes(named Pbam-32,P6/mmm,and I43d)were recently uncovered based on a random sampling strategy combined with space group and graph theory.The calculation results show that they are superhard and remarkably stable compared with previously proposed metastable phases.This indicates that they are likely to be synthesized in experiment.We use the factor group analysis method to analyze theirΓ-point vibrational modes.Owing to their large number of atoms in primitive unit cells(32 atoms in Pbam-32,36 atoms in P6/mmm,and 94 atoms in I43d),they have many Raman-and infrared-active modes.There are 48 Raman-active modes and 37 infrared-active modes in Pbam-32,24 Raman-active modes and 14 infrared-active modes in P6/mmm,and 34 Raman-active modes and 35 Raman-and infrared-active modes in I43d.Their calculated Raman spectra can be divided into middle frequency range from 600 cm-1 to 1150 cm-1 and high frequency range above 1150 cm-1.Their largest infrared intensities are 0.82,0.77,and 0.70(D/Å)2/amu for Pbam,P6/mmm,and I43d,respectively.Our calculated results provide an insight into the lattice vibrational spectra of these sp3 carbon allotropes and suggest that the middle frequency Raman shift and infrared spectrum may play a key role in identifying newly proposed carbon allotropes.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.61762012,61763014,and 62062035)the Science and Technology Project of Guangxi(Grant No.2020GXNSFDA238023).
文摘A fault-tolerant circuit is required for robust quantum computing in the presence of noise.Clifford+T circuits are widely used in fault-tolerant implementations.As a result,reducing T-depth,T-count,and circuit width has emerged as important optimization goals.A measure-and-fixup approach yields the best T-count for arithmetic operations,but it requires quantum measurements.This paper proposes approximate Toffoli,TR,Peres,and Fredkin gates with optimized T-depth and T-count.Following that,we implement basic arithmetic operations such as quantum modular adder and subtractor using approximate gates that do not require quantum measurements.Then,taking into account the circuit width,T-depth,and T-count,we design and optimize the circuits of two multipliers and a divider.According to the comparative analysis,the proposed multiplier and divider circuits have lower circuit width,T-depth,and T-count than the current works that do not use the measure-and-fixup approach.Significantly,the proposed second multiplier produces approximately 77%T-depth,60%T-count,and 25%width reductions when compared to the existing multipliers without quantum measurements.
基金supported by the National Basic Research Program (973) of China (No. 2012CB821206)the National Natural Science Foundation of China (No. 71201004)+1 种基金the Scientific Research Common Program of Beijing Municipal Commission of Education (No. KM201310011009)the Funding Project for Innovation on Science, Technology and Graduate Education in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (Nos. PXM2012_014213_000037 and PXM2012_014213_000079)
文摘Object representation based on local features is a topical subject in the domain of image understanding and computer vision. We discuss the defects of global features in present methods and the advantages of local features in object recognition, and briefly explore state-of-the-art recognition methods using local features, especially the main approaches of local feature extraction and object representation. To clearly explain these methods, the problem of local feature extraction is divided into feature region detection, feature region description, and feature space optimization. The main components and merits of these steps are presented. Technologies for object presentation are classified into three types: vector space, sliding window, and structure relationship models. Future development trends are discussed briefly.
基金supported by the National Natural Science Foundation of China(Grant Nos.61762012,and 61763014)the Science and Technology Project of Guangxi(Grant No.2018JJA170083)+3 种基金the National Key Research and Development Plan(Grant Nos.2018YFC1200200,and 2018YFC1200205)the Fund for Distinguished Young Scholars of Jiangxi Province(Grant No.2018ACB2101)the Natural Science Foundation of Jiangxi Province of China(Grant No.20192BAB207014)the Science and Technology Research Project of Jiangxi Provincial Education Department(Grant No.GJJ190297)。
文摘Efficient quantum circuits for arithmetic operations are vital for quantum algorithms.A fault-tolerant circuit is required for a robust quantum computing in the presence of noise.Quantum circuits based on Clifford+T gates are easily rendered faulttolerant.Therefore,reducing the T-depth and T-Count without increasing the qubit number represents vital optimization goals for quantum circuits.In this study,we propose the fault-tolerant implementations for TR and Peres gates with optimized T-depth and T-Count.Next,we design fault-tolerant circuits for quantum arithmetic operations using the TR and Peres gates.Then,we implement cyclic and complete translations of quantum images using quantum arithmetic operations,and the scalar matrix multiplication.Comparative analysis and simulation results reveal that the proposed arithmetic and image operations are efficient.For instance,cyclic translations of a quantum image produce 50%T-depth reduction relative to the previous best-known cyclic translation.
文摘The precise mechanism of bone regeneration in different bone graft substitutes has been well studied in recent researches. However, miRNAs regulation of the bone formation has been always mysterious. We developed the anterior lumbar interbody fusion (ALIF) model in pigs using equine bone protein extract (BPE), recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge (ACS), and autograft as bone graft substitute, respectively. The miRNA and gene expression profiles of different bone graft materials were examined using microarray technology and data analysis, including self-organizing maps, KEGG pathway and Biological process GO analyses. We then jointly analyzed miRNA and mRNA profiles of the bone fusion tissue at different time points respectively. Results showed that miRNAs, including let-7, miR-129, m iR-21, miR-133, miR-140, miR-146, miR-184, and miR-224, were involved in the regulation of the immune and inflammation response, which provided suitable inflammatory microenvironment for bone formation. At late stage, several miRNAs directly regulate SMAD4, Estrogen receptor 1 and 5-hydroxytryptamine (serotonin) receptor 2C for bone formation. It can be concluded that miRNAs play important roles in balancing the inflammation and bone formation.
基金This work was partially supported by the National Natural Science Foundation of China under Grant No. 61602015, the Open Funding Project of State Key Laboratory of Virtual Reality Technology and Systems at Beihang University under Grant No. BUAAVR-16KF-06, Beijing Natural Science Foundation under Grant No. 4162019, and the Research Foundation for Young Scholars of Beijing Technology and Business University.
文摘This paper presents a novel algorithm for automatically detecting global shakiness in casual videos. Per-frame amplitude is computed by the geometry of motion, based on the kinematic model defined by inter-frame geometric transformations. Inspired by motion perception, we investigate the just-noticeable amplitude of shaky motion perceived by the human visual system. Then, we use the thresholding contrast strategy on the statistics of per-frame amplitudes to determine the occurrence of perceived shakiness. For testing the detection accuracy, a dataset of video clips is constructed with manual shakiness label as the ground truth. The experiments demonstrate that our algorithm can obtain good detection accuracy that is in concordance with subjective judgement on the videos in the dataset.