检索结果-南通市图书馆

Chinese Journal of Electronics 2014年第2期23卷 361-365页

作者： yin Hongtao fu Ping SUN Zhen Automatic Test and Control Institute Harbin Institute of Technology

Discrete cosine transform(DCT) is an effective method to extract proper features for face recognition. Discrete cosine transform can only map the resource data to another data field instead of compress *** to select the DCT coefficients that are most effective for classification is an important problem. This paper proposes a novel method to search the best discriminant combination of DCT coefficients. A feature selection algorithm according to the separability criterion is used to preselect the DCT coefficients, and then follows a search algorithm based on binary particle swarm optimization and support vector machine to find an optimal combination of the DCT coefficient. The performance of the algorithm is assessed by computing the recognition rate and the number of selected features on ORL database and Cropped Yale database.

关键词： Separability criterion Binary particle swarm optimization Support vector machine Face recognition Feature selection

Discovery of a new family member of arsenic–vanadium polyoxometalates with high catalytic performance for one-pot coupling of CO2, epoxides and amines

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Tungsten 2025年第1期 80-87页

作者： Fang-Qian Wang yin Zhang Wei-Wei Wang Mei-Qian fu Hong-Bing Mo Wei-Dong Yu Chao Liu Jun Yan College of Chemistry and Chemical Engineering Central South University Junior Education Department Changsha Normal University School of Science Hunan University of Technology and Business

Arsenic-vanadium polyoxometalates（POMs） represent a family of tremendous potential catalysts owing to their peculiar physical and chemical *** in CO2conversion,using POMs to catalyze the conversion of CO2and epoxide into chemical intermediates is the research ***,A new family number of arsenic-vanadium POMs,[N（CH3）4]4[As8V12O38（H2O）]·2H2O({As8V12O38}),was reported and characterized by single-crystal X-ray diffraction,fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,*** from other allotropicity,{As8V12O38}shows a different structure pattern with an I-43d *** obtained {As8V12O38} was employed as a catalyst for the *** initial catalytic reaction confirmed that {As8V12O38} can catalyze the formation of epoxy carbonate by using 1.01 kPa CO2and epoxide at 70℃.furtherly,when added amine in the catalytic system,oxazolidinone could be obtained by high yields,which provides an efficient way to convert CO2into profitable ***,a possible catalytic reaction mechanism was proposed by using different characterization analyses.{As8V12O38} first catalyzes the epoxide and CO2to form an epoxy carbonate and then catalyzes epoxy carbonate and benzylamine into oxazolidinone.

关键词：

Calculation of f_(σ) on Quark Level

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第9期13卷 652-655页

作者： LÜXiao-fu LIU Yu-xin ZHAO En-guang Department of Physics Sichuan UniversityChengdu 610064 Department of Physics Peking UniversityBeijing 100871 Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100080

With the recently obtained vacuum configuration of the bilocal field,we have calculated the decay constant f_(σ) of σ-meson in a quantum chromodynamics-based model field *** investigating the calculated result,it ca... 详细信息

关键词： theory decay meson

First-Principle Calculations for Elastic and Thermodynamic Properties of Diamond

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

Communications in Theoretical Physics 2009年第6期51卷 1129-1134页

作者： fu Zhi-Jian JI guang-fu CHEN Xiang-Rong GOU Qing-Quan Institute of Atomic and Molecular Physics Sichuan University Chengdu 610065 China Laboratory for Shock Wave and Detonation Physics Research Institute of Fluid Physics Chinese Academy of Engineering Physics Mianyang 621900 China International Centre for Materials Physics Chinese Academy of Sciences Shenyang 110016 China

The elastic constants and thermodynamic properties of diamond are investigated by using the CRYSTALO3 program. The lattice parameters, the bulk modulus, the heat capacity, the Gruneieen parameter, and the Debye temperature are obtained. The results are in good agreement with the available experimental and theoretical data. Moreover, the relationship between V/V0 and pressure, the elastic constants under high pressure are successfully obtained. Especially, the elastic constants of diamond under high pressure are firstly obtained theoretically. At the same time, the variations of the thermal expansion α with pressure P and temperature Tare obtained systematically in the ranges of 0-870 GPa and 0-1600 K.

关键词： density functional theory elastic constants thermodynamic properties diamond

New Approach for Measured Surface Localization Based on Umbilical Points

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2017年第5期30卷 1203-1215页

作者： Xiao-Ping Xiao Ming yin Liang Heng Guo-fu yin Zi-Sheng Li School of Manufacturing Science and Engineering Sichuan University Center of Engineering and Technology Southwest University of Science and Technology School of Manufacturing Science and Engineering Southwest University of Science and Technology

Measured surface localization （MSL） is one of the key essentials for the assessment of form error in pre- cision manufacturing. Currently, the researches on MSL have focused on the corresponding relation search between two surfaces, the performance improvement of localization algorithms and the uncertainty analysis of localization. However, low efficiency, limitation of localization algo- rithms and mismatch of multiple similarities of feature points with no prior are the common disadvantages for MSL. In order to match feature points quickly and fulfill MSL efficiently, this paper presents a new localization approach for measured surfaces by extracting the generic umbilics and estimating their single complex variables, describing the match methods of ambiguous relation at umbilics, presenting the initial localization process of one pair matched points, refining MSL on the basis of obtained closet points for some measured points by the improvement directed projection method. In addition, the proposed algorithm is simulated in two different types of surfaces,two different localization types and multiple similar sur- faces, also tested with the part of B-spline surface machined and bottle mould with no knowledge, finally the initial and accurate rigid body transformation matrix, localization errors between two surfaces and execution time are got. The experimental results show that the pro- posed method is feasible, more accurate in localization and high in efficiency. The proposed research can not only improve the accuracy and performance of form error assessment, but also provide an effective guideline for the integration of different types of measured surfaces.

关键词： Measured surface localization Umbilicalpoints and complex variable Similar surface patchesInitial and accurate localization

Multi-fidelity Gaussian process based empirical potential development for Si:H nanowires

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2020年第3期10卷 195-201页

作者： Moonseop Kim Huayi yin guang Lin School of Mechanical Engineering Purdue UniversityWest LafayetteIN 47906-2045USA School of Computer and Information Engineering Xiamen University of TechnologyXiamen 361024China Department of Mathematics Purdue UniversityWest LafayetteIN 47906-2045USA

In material modeling,the calculation speed using the empirical potentials is fast compared to the first principle calculations,but the results are not as accurate as of the first principle *** principle calculations are accurate but slow and very expensive to *** this work,first,the H-H binding energy and H2-H2 interaction energy are calculated using the first principle calculations which can be applied to the Tersoff empirical ***,the H-H parameters are *** fitting H-H parameters,the mechanical properties are ***,to integrate both the low-fidelity empirical potential data and the data from the high-fidelity firstprinciple calculations,the multi-fidelity Gaussian process regression is employed to predict the HH binding energy and the H2-H2 interaction *** results demonstrate the accuracy of the developed empirical potentials.

关键词： Multi-fidelity Gaussian process regression Inter-atomic potential and forces Elasticity

Effects of Nb Addition on Charpy Impact Properties of TiVTa Refractory High‑Entropy Alloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2023年第3期36卷 405-416页

作者： Xue yin Yan‑Kun Dou Xin‑fu He Ke Jin Cheng‑Long Wang Ya‑guang Dong Cun‑Yong Wang Yun‑Fei Xue Wen Yang Department of Reactor Engineering Technology Research China Institute of Atomic EnergyBeijing 102413China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Advance Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China

In the present study,the effects of Nb addition on Charpy impact properties of TiVTa refractory high-entropy alloy with high strength-ductility trade-off were systematically studied by using the instrumented Charpy impact testing *** experimental results showed that the impact toughness was remarkably improved by Nb addition in TiVTa to form TiVTaNb *** crack initiation energy and propagation energy of TiVTaNb were 67.3%and 24.9%higher than that of TiVTa,indicating that Nb addition simultaneously reinforced the resistance to crack initiation and *** impact fracture of TiVTaNb exhibited larger bending degree of shear lips,deeper dimples and more secondary cracks which effectively dissipated more impact *** deformation mechanism of TiVTa alloy was dominated by dislocation *** in TiVTaNb,the deformation mechanism was synergized by dislocation activities and deformation twinning,which were the main contributors for the improved impact properties and the stronger crack resistance of TiVTaNb alloy under impact loading.

关键词： Refractory high-entropy alloys Nb addition Impact property Crack resistance Deformation mechanism

Targets and beyond:cancer stem cell elimination

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

Science Bulletin 2017年第16期62卷 1104-1105页

作者： Anqi Wu guang Shu Jing Wang Gang yin Department of Pathology Xiangya HospitalCentral South University Department of Pathology School of Basic Medicine SciencesCentral South University

Cancer stem cells(CSCs)have been reported in various cancer types.A small portion of tumor cells that possess tumor initiation capacity,resist conventional drug treatment and correlate with poor prognosis are believed to be essential to drive tumor progression and ***,successfully targeting CSCs is a promising strategy of cancer treatment.

关键词：肿瘤干细胞癌症治疗肿瘤细胞药物治疗

Purinergic Signaling in the Central Nervous System in Health and Disease

在线全文

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2020年第11期36卷 1239-1241页

作者： Peter Illes guang-yin Xu Yong Tang International Collaborative Centre on Big Science Plan for Purine Signaling Chengdu University of Traditional Chinese MedicineChengdu 610075China Rudolf-Boehm-Institut fur Pharmakologie und Toxikologie Universitaet LeipzigLeipzig 04107Germany Institute of Neuroscience Soochow UniversitySuzhou 215123China Acupuncture and Chronobiology Key Laboratory of Sichuan Province Chengdu 610075China

The existence of purinergic signaling—the idea that almost all cells of the animal/human organism are able to communicate with each other via extracellular purines—was proposed by Geoffrey Burnstock(1929-2020)in 1972[1-3].The purinergic system includes the following constituents:(1)the four main purines:adenosine triphosphate(ATP)and its metabolites,adenosine diphosphate(ADP),adenosine monophosphate(AMP),and adenosine(ADO);(2)three key enzymes,the ectonucleoside triphosphate diphosphohydrolases(E-NTPDases:NTPDase1/CD39),ectonucleotide pyrophosphatase/phosphodiesterases(E-NPP),and ecto-5’-nucleotidase(E-5’-nucleotidase/CD73),which decompose ATP into ADP,AMP,and ADO.

关键词： ADO urine include

Two birds with one stone: Simultaneous fabrication of HfC nanowires and CNTs through efficient utilization of polymer-derived ceramics

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第34期129卷 163-172页

作者： Yanqin fu Yulei Zhang Xuemin yin Liyuan Han Qiangang fu Hejun Li Ralf Riedel Shaanxi Province Key Laboratory of Fiber Reinforced Light Composite Materials Northwestern Polytechnical UniversityXi’an 710072China Technische Universität Darmstadt Institut für MaterialwissenschaftOtto-Berndt-Straβe 3Darmstadt D-64287Germany

Carbon nanotubes(CNTs) are fabricated in carbon cloth by ultilizing the waste gasses when fabricating hafnium carbide nanowires(HfC_(NWS)) through thermal pyrolysis of Hf-containing polymer *** formed HfC_(NWS) are distributed uniformly on the surface of the carbon fibers in carbon/carbon(C/C) composites and display perfect single crystal *** pyrolysis of the Hf-containing organic precursor provides hafnium and carbon source for the growth of HfC_(NWS).The released waste gasses containing CO,CH4and CO_(2)are the main carbon source for the growth of ***,the flexural strength of HfC_(NWS) reinforced carbon/carbon(HfC_(NWS)-C/C) composites is enhanced by ~105% compared with pure C/C,and the CNTs/carbon cloth also displays improved electrochemical performance with respect to capacitor *** present study introduces a novel sustainable and eco-friendly process related to polymer-derived ceramics to form advanced ceramic nanocomposites and proposes a deep understanding of the growth mechanism of CNTs.

关键词： HfC nanowires Carbon nanotubes Waste gasses Effective utilization Polymer-derived ceramics