检索结果-南通市图书馆

Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 166-180页

作者： Dengke Zhou Pei Wang Di li Jianhua Fang Chenchen Miao Paulo CCFreire Lei Zhang Dandan Zhang Huaxi Chen Yi Feng Yifan Xiao Jintao Xie Xu Zhang Chenwu Jin Han Wang Yinan ke Xuerong Guo Rushuang Zhao Chenhui Niu Weiwei Zhu Mengyao Xue Yabiao Wang Jiafu Wu Zhenye Gan Zhongyi Sun Chengjie Wang Jie Zhang Junshuo Zhang Jinhuang Cao Wanjin Lu Research Center for Astronomical Computing Zhejiang LaboratoryHangzhou 311121China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China university of Chinese Academy of Sciences Beijing 100049China New Cornerstone Science Laboratory Shenzhen 518054China Max Planck Institut f¨ur Radioastronomie Bonn 53121Germany Centre for Astrophysics and Supercomputing Swinburne University of TechnologyHawthorn 3122Australia School of Mathematical Sciences School of Physics and Electronic SciencesGuizhou Normal UniversityGuiyang 550001China Guizhou Provincial key Laboratory of Radio Astronomy and Data Processing Guiyang 550001China School of Physics and Electronic Engineering Qilu Normal UniversityJinan 250200China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China College of physical Science and Technology Central China Normal UniversityWuhan 430079China Tencent Youtu Lab Shanghai 201103China

Globular clusters harbor numerous millisecond pulsars,but long-period pulsars(P 100 ms)are rarely *** this study,we employed a fast folding algorithm to analyze observational data from multiple globular clusters obtained by the Five-hundredmeter Aperture Spherical radio Telescope(FAST),aiming to detect the existence of long-period *** estimated the impact of the median filtering algorithm in eliminating red noise on the minimum detectable flux density(S_(min))of ***,we successfully discovered two isolated long-period pulsars in M15 with periods approximately equal to 1.928451 and3.960716 s,*** the P-˙P diagram,both pulsars are positioned below the spin-up line,suggesting a possible history of partial recycling in X-ray binary systems disrupted by dynamical encounters later *** to timing results,these two pulsars exhibit remarkably strong magnetic *** the magnetic fields were weakened during the accretion process,then a short duration of accretion might explain the strong magnetic fields of these pulsars.

关键词： pulsar globular cluster FAST

在线全文

学校读者我要写书评

暂无评论

基于XML的体育数据规格化存储技术研究

计算机工程与应用 2001年第22期37卷 6-7,94页

作者：李天庆张毅张冰胡东成清华大学自动化系北京100084 清华大学体育教研部北京100084

计算机辅助体育训练是融合了信息技术、生物力学和运动训练学的交叉学科,而体育训练数据的规格化存储问题又是它的基础。由于体育训练数据项本身不确定性,使得传统技术很难灵活地记录训练数据。可扩展标记语言XML是W3.提出的一种元标记... 详细信息

计算机辅助体育训练是融合了信息技术、生物力学和运动训练学的交叉学科,而体育训练数据的规格化存储问题又是它的基础。由于体育训练数据项本身不确定性,使得传统技术很难灵活地记录训练数据。可扩展标记语言XML是W3.提出的一种元标记语言。该文介绍了清华大学体能训练系统采用XML技术存储体育训练数据的方法,从而克服了数据项的不确定性问题,还使得被存储数据具有灵活的扩展性和良好的自描述性。

关键词：运动训练学 XML 体育训练数据规格化存储计算机

Interface-rich Au-doped PdBi alloy nanochains as multifunctional oxygen reduction catalysts boost the power density and durability of a direct methanol fuel cell device

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第7期15卷 6036-6044页

作者： Xin li ke Xin Yao Fengling Zhao Xiaotong Yang Jingwei li Yongfei li Qiang Yuan State-Local Joint Laboratory for Comprehensive Utilization of Biomass Center for R&D of Fine ChemicalsCollege of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China State key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China key Lab of Organic Optoelectronics&Molecular Engineering Tsinghua UniversityBeijing 100084China Multi-scale Porous Materials Center Institute of Advanced Interdisciplinary Studies&School of Chemistry and Chemical EngineeringChongqing UniversityChongqing 400044China

The development of cathode oxygen reduction reaction(ORR)catalysts with high characteristics for practical,direct methanol fuel cells(DMFCs)has continuously increased the attention of *** this work,interface-rich Au-doped PdBi(PdBiAu)branched one-dimensional(1D)alloyed nanochains assembled by sub-6.5 nm particles have been prepared,exhibiting an ORR mass activity(MA)of 6.40 A·mgPd^(−1) and long-term durability of 5,000 cycles in an alkaline *** MA of PdBiAu nanochains is 46 times and 80 times higher than that of commercial Pt/C(0.14 A·mgPt^(−1))and Pd/C(0.08 A·mgPd^(−1)).The MA of binary PdBi nanochains also reaches 5.71 A·mgPd^(−1).Notably,the PdBiAu nanochains exhibit high in-situ carbon monoxide poisoning resistance and high methanol *** actual DMFC device tests,the PdBiAu nanochains enhance power density of 140.1 mW·cm^(−2)(in O_(2))/112.4 mW·cm^(−2)(in air)and durability compared with PdBi nanochains and Pt/*** analysis of the structure–function relationship indicates that the enhanced performance of PdBiAu nanochains is attributed to integrated functions of surficial defect-rich 1D chain structure,improved charge transfer capability,downshift of the d-band center of Pd,as well as the synergistic effect derived from“Pd-Bi”and/or“Pd-Au”dual active sites.

关键词： Au-doped PdBi(PdBiAu)nanochains one-dimensional structure active auxiliary oxygen reduction reaction direct methanol fuel cells

Low-coordinated surface sites make truncated Pd tetrahedrons as robust ORR electrocatalysts outperforming Pt for DMFC devices

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2022年第9期15卷 7951-7958页

作者： Xiaoling Wang Jingwei li Xiaotong Yang Fengling Zhao Yongfei li Daliang Zhang li-Yong Gan ke Xin Yao Qiang Yuan State-Local Joint Laboratory for Comprehensive Utilization of Biomass Center for R&D of Fine ChemicalsCollege of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China State key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China key Lab of Organic Optoelectronics&Molecular Engineering Tsinghua UniversityBeijing 100084China Multi-scale Porous Materials Center Institute of Advanced Interdisciplinary Studies&School of Chemistry and Chemical EngineeringChongqing UniversityChongqing 400044China College of Physics and Center of Quantum Materials and Devices Chongqing UniversityChongqing 401331China

Developing highly stable and active non-Pt oxygen reduction reaction(ORR)electrocatalysts for power generation device raises great concerns and remains a ***,we report novel truncated Pd tetrahedrons(T-Pd-Ths)enclosed by{111}facets with excellent uniformity,which have both low-coordinated surface sites and distinct lattice distortions that would induce“local strain”.In alkaline electrolyte,the T-Pd-Ths/C achieves remarkable ORR specific/mass activity(SA/MA)of 2.46 mA·cm^(−2)/1.69 A·mgPd^(−1),which is 12.3.16.9 and 10.7/14.1 times higher than commercial Pd/C and Pt/C,*** T-Pd-Ths/C also exhibits high in-situ carbon monoxide(CO)tolerance and 50,000 cycles durability with an activity loss of 7.69%and morphological *** rotating ring-disk electrode(RRDE)measurements show that a 4-electron process occurs on T-PdThs/*** calculations demonstrate that the low-coordinated surface sites contribute largely to the enhancement of ORR *** actual direct methanol fuel cell(DMFC)device,the T-Pd-Ths/C delivers superior open-circuit voltage(OCV)and peak power density(PPD)to commercial Pt/C from 25 to 80℃,and the maximum PPD can reach up to 163.7 mW·cm−*** study demonstrates that the T-Pd-Ths/C holds promise as alternatives to Pt for ORR in DMFC device.

关键词： Pd tetrahedrons low-coordinated sites lattice distortion oxygen reduction reaction direct methanol fuel cells

Landau quantization of Dirac fermions in graphene and its multilayers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2017年第4期12卷 85-121页

作者： Long-Jing Yin ke-ke Bai Wen-Xiao Wang Si-Yu li Yu Zhang lin He The Center for Advanced Quantum Studies Department of Physics Beijing Normal University Beijing 100875 China

When electrons are confined in a two-dimensional （2D） system, typical quantum-mechanical phenonl- ena such as Landau quantization can be detected. Graphene systems, including the single atomic layer and few-layer stacked crystals, are ideal 2D materials for studying a variety of quantum-mechanical problems. In this article, we review the experimental progress in the unusual Landau quantized behav- iors of Dirac fernlions in monolayer and multilayer graphene by using scanning tunneling microscopy （STM） and scanning tulmeling spectroscopy （STS）. Through STS measurement of the strong mag- netic fields, distinct Landau-level spectra and rich level-splitting phenomena are observed in different graphene layers. These unique properties provide an effective method for identifying the number of layers, as well as the stacking orders, and investigating the fllndamentally physical phenomena of graphene. Moreover, in the presence of a strain and charged defects, the Landau quantization of graphene can be significantly modified, leading to unusual spectroscopic and electronic properties.

关键词： Landau quantization graphene STM/STS stacking order strain and defect

Development of an electronic stopping power model based on deep learning and its application in ion range prediction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第7期31卷 255-261页

作者： Xun Guo Hao Wang Changkai li Shijun Zhao ke Jin Jianming Xue Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China State key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China department of Mechanical Engineering City University of Hong KongHong KongChina Center for Applied Physics and Technology Ministry of Education Key Laboratory of High Energy Density Physics Simulationsand Peking University Branch of Ministry of Education IFSA CenterPeking UniversityBeijing 100871China

Deep learning algorithm emerges as a new method to take the raw features from large dataset and mine their deep implicit relations,which is promising for solving traditional physical challenges.A particularly intricate and difficult challenge is the energy loss mechanism of energetic ions in solid,where accurate prediction of stopping power is a longtime *** this work,we develop a deep-learning-based stopping power model with high overall accuracy,and overcome the long-standing deficiency of the existing classical models by improving the predictive accuracy of stopping power for ultra-heavy ion with low energy,and the corresponding projected *** electronic stopping power model,based on deep learning algorithm,could be hopefully applied for the study of ion-solid interaction mechanism and enormous relevant applications.

关键词： electronic stopping power deep learning ion range reciprocity theory

Single molecular insight into steric effect on C-terminal amino acids with various hydrogen bonding sites

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2022年第10期33卷 4649-4654页

作者： Yunzhi Xie Chunhua liu linxiu Cheng Yulan Fan Huifang li Wei liu Lei Zhu Xun li ke Deng Qingdao Zeng Shoufa Han State key Laboratory for physical Chemistry of Solid Surfaces Department of Chemical BiologyCollege of Chemistry and Chemical EngineeringThe Key Laboratory for Chemical Biology of Fujian ProvinceThe MOE Key Laboratory of Spectrochemical Analysis&Instrumentationand Innovation Center for Cell Signaling NetworkXiamen UniversityXiamen 361005China Jiangxi Provincial key Laboratory of Low-Carbon Solid Waste Recycling School of Geography and Environmental EngineeringGannan Normal UniversityGanzhou 341000China Jiangxi key Laboratory of Organo-Pharmaceutical Chemistry Chemistry and Chemical Engineering CollegeGannan Normal UniversityGanzhou 341000China CAS key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for Nanoscience and Technology(NCNST)Beijing 100190China

Amino acids are basic units to construct a protein with the assistance of various *** this building process,steric hindrance derived from amino acid side groups or side chains is a factor that could not be *** this contribution,adsorption behaviors of C-terminal amino acid derivatives with amino acid residues fused in 3.4,9,10-perylenetetracarboxylic dianhydride were investigated by scanning tunneling microscopy(STM)and density functional theory(DFT)calculations at various liquid/solid *** results at 1-phenyloctane/HOPG interface show that N,N'-3.4,9,10-perylenedicarboximide(GP)and N,N'-methyl-3.4,9,10-perylenedicarboximide(AP)formed linear and herringbone structures,*** driving force could be attributed to different H-bonding sites induced by steric hindrance at side groups.N,N'-Benzyl-3.4,9,10-perylenedicarboximide(PP)generates both linear and herringbone structures because steric hindrance changes the H-bonding sites between PP molecules,whereas N,N'-isopropyl-3.4,9,10-perylenedicarboximide(LP)failed to be imaged because of strong steric hindrance coming from larger side *** further investigate the impact of steric hindrance,we utilized octanoic acid(OA)as solvent to capture the adsorption details of LP and *** found that OA molecules drag PP and LP molecules in a different direction to generate linear structure,impeding the molecular *** structure–solvent relationship shows that the steric hindrance is brought by the large side group,which makes it easier to recognize OA molecules at the *** results demonstrate that steric effect plays a significant role in altering interaction sites of the compounds during the adsorption process at the liquid/solid interface.

关键词： C-terminal amino acids Steric effect Bonding site Scanning tunneling microscopy DFT calculations

基于模式识别的高水平运动员RS-fMRI数据分类研究

在线全文

学校读者我要写书评

暂无评论

科学技术与工程 2024年第8期24卷 3145-3154页

作者：张可盈张栋丁宇曹春梅东南大学体育系南京210018 清华大学体育部北京100084 首都体育学院体育人工智能研究院北京100191 北京语言大学心理学院北京100083

为弥补传统的广义线性模型(generalized linear model,GLM)方法的不足,并探索模式识别在运动脑科学当中的应用价值。使用支持向量机(support vector machine,SVM)模式识别算法,以低频振幅(fractional amplitude of low-frequency fluctuations,fALFF)、局部一致性(regional homogeneity,ReHo)和度中心度(degree centrality,DC)作为学习特征,对射击运动组和滑冰运动组(分类1)、射击运动组和对照组(分类2)以及速滑运动组和对照组(分类3.之间进行二分类,并计算每一个脑区在分类算法当中的权重。使用留一交叉验证法计算分类正确率,使用总的准确率、接受者操作特性曲线(receiver operating characteristic curve,ROC)、以及预测准确率来衡量机器分类算法的优劣性。结果表明:分类1中SVM算法的正确率较高且分类效果更稳定,总的准确率(total accuracy,tACC)可以维持在96.67%以上,曲线下面积(area under curve,AUC)均为1,说明SVM算法对区分不同项目运动员脑静息态功能特征时更有优势;在分类2和分类3.,SVM算法效果取决于使用的指标。其中,使用fALFF或者综合使用三个静息态指标的分类效果较稳定(tACC均在80%以上,AUC均在0.88以上);小脑在分类1算法中占较多的权重,提示不同运动项目运动员的脑功能活动之间差异最明显的部位主要在小脑上。而分类2和3.,除了小脑,还有一些与运动执行和控制及其他功能活动相关的脑区参与了算法的构成。通过SVM分类算法的应用获得较为理想的结果,展示了模式识别方法在运动科学领域的应用价值。研究成果有助于体育科学研究者从新的角度更加全面地理解运动与脑的关系。

关键词：模式识别高水平运动员功能磁共振成像(fMRI) 脑静息态

长期参与有氧运动大学生执行功能相关脑网络特征

在线全文

学校读者我要写书评

暂无评论

科学技术与工程 2024年第10期24卷 4013-4019页

作者：张可盈张栋丁宇曹春梅东南大学体育系南京211102 首都体育学院体育人工智能研究院北京100191 北京语言大学心理学院北京100083 清华大学体育部北京100084

为了探索长期参与有氧运动的男性大学生执行功能相关脑网络的特征,并与静坐少动的对照组进行比较。收集15名规律参与有氧运动的男性大学生以及15名静坐少动对照组男性大学生脑结构及静息态功能磁共振成像数据。使用度中心度和独立成分... 详细信息

为了探索长期参与有氧运动的男性大学生执行功能相关脑网络的特征,并与静坐少动的对照组进行比较。收集15名规律参与有氧运动的男性大学生以及15名静坐少动对照组男性大学生脑结构及静息态功能磁共振成像数据。使用度中心度和独立成分分析两种方法评价脑网络特征:计算并提取14个执行功能相关脑区度中心度值(degree centrality,DC),采用独立成分分析方法(independent component analysis,ICA)提取4个与执行功能相关的脑网络成分。组间对比发现:有氧运动组双侧后扣带回皮层以及双侧海马区度中心度水平显著高于静坐少动组(p<0.05),而静坐少动组右侧顶下小叶度中心度水平显著高于有氧运动组(p<0.05);有氧运动组在默认网络、背侧注意网络及腹侧注意网络均有脑区激活高于静坐少动组,峰值分别出现在右颞下回、颞极以及左腹侧后扣带回(AlphaSim校正,p<0.001);而静坐少动组腹侧注意网络在左侧在壳核高于有氧运动组(AlphaSim校正,p<0.001)。研究结果表明:长期参与有氧运动的大学生,其执行功能相关脑网络激活模式优于静坐少动大学生,而这种差异主要是通过增加海马和后扣带回皮层而不是额叶皮层在脑网络中的重要性来实现的。

关键词：有氧运动执行功能大学生脑网络