检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

Metric of States

Communications in Theoretical Physics 2008年第11期50卷 1069-1070页

作者： ma Zhi-hao Department of mathematics Shanghai Jiao Tong University Shanghai 200240 China

Metric of quantum states plays an important role in quantum information theory. In this letter, we find the deep connection between quantum logic theory and quantum information theory. Using the method of quantum logi... 详细信息

关键词： state density operator metric fidelity quantum information quantum logic

Crossover Phenomena in Detrended Fluctuation Analysis Used in Financial markets

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2009年第2期51卷 358-362页

作者： ma Shi-hao College of Physical Science and Technology Huazhong Normal University Wuhan 430079 China

A systematic analysis of Shanghai and Japan stock indices for the period of Jan. 1984 to Dec. 2005 is performed. After stationarity is verified by ADF （Augmented Dickey-Fuller） test, the power spectrum of the data exhibits a power law decay as a whole characterized by 1/f^β processes with possible long range correlations. Subsequently, by using the method of detrended fluctuation analysis （DFA） of the general volatility in the stock markets, we find that the long-range correlations are occurred among the return series and the crossover phenomena exhibit in the results ***, Shanghai stock market shows long-range correlations in short time scale and shows short-range correlations in long time scale. Whereas, for Japan stock market, the data behaves oppositely absolutely. Last, we compare the varying of scale exponent in large volatility between two stock markets. All results obtained may indicate the possibility of characteristic of multifractal scaling behavior of the financial markets.

关键词： financial market crossover phenomena detrended fluctuation analysis

Improving interlaminar fracture toughness of flax fiber/epoxy composites with chopped flax yarn interleaving

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第10期58卷 1745-1752页

作者： LI Yan WANG Di ma hao School of Aerospace Engineering and Applied Mechanics Tongji University Key Laboratory of Advanced Civil Engineering materials Ministry of Education Tongji University

In this research, unidirectional flax fabrics reinforced epoxy laminates were intedeaved with randomly oriented chopped flax yarns at various yarn lengths and contents. Mode I interlaminar fracture toughness of the laminates was evaluated via Double Cantilever Beam （DCB） tests. The results showed that Mode I interlaminar fracture toughness increased with the introduction of the chopped yarns. With moderate yarn length and content, the best toughening effect （31% improvement in Mode I inter- laminar fracture toughness） was achieved. It was observed with the aid of Scanning Electronic Microscopy （SEM） that the in- troduction of the chopped yarns resulted in more tortuous in-plane crack propagation paths as well as the ＂trans-layer＂ phe- nomenon and fiber bridging effect of both the unidirectional yams and the chopped yams. These hindered the growth of the crack and led to more energy dissipation during delamination progress. Excessive yam length or content would induce unstable crack propagation and thus weakened the toughening improvement. No remarkable change was found in the tensile properties and the Charpy impact strength for the interleaved laminates, which indicated that this interleaving method was effective on interlaminar toughening without sacrificing the comprehensive mechanical properties of the laminates.

关键词： natural fiber reinforced composites interlaminar fracture toughness interlaminar toughening interleaving fiberbridging trans-layer effect

Construction of Authentication Codes with Double Arbiters over Symplectic Geometry

在线全文

学校读者我要写书评

暂无评论

Acta mathematicae Applicatae Sinica 2015年第4期31卷 1141-1152页

作者： Shang-di CHEN hao ma College of Science Civil Aviation University of China

In a common authentication code with arbitration, the dishonest arbiter may make a threat to the security of authentication system. In this paper, an authentication code with double arbiters over symplectic geometry is constructed, and the relevant parameters and the probabilities of successful attacks are calculated. The model not only prevents deception from the opponent and members of the system, but also effectively limits the attacks of single arbiter. Moreover, the collusion attacks from arbiters and participators are difficult to succeed.

关键词： authentication code double arbiters symplectic geometry

Two constructions of A^3-codes from projective geometry in finite fields

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2015年第2期22卷 52-59页

作者： Chen Shangdi Zhang Xiaollian ma hao College of Science Civil Aviation University of China

An A^3-code is extension of A^2-code in which none of the three participants： transmitter, receiver and arbiter, is assumed trusted. In this article, from projective geometry over finite fields, two A^3 -codes were g... 详细信息

关键词： projective geometry finite field authentication A^3-cOde

Changes in freezing and thawing indices over the source region of the Yellow River from 1980 to 2014

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2019年第1期30卷 257-268页

作者： Rui Wang Qingke Zhu hao ma School of Geography and Tourism Shaanxi Normal University School of Soil and Water Conservation Beijing Forestry University Northwest Institute of Forest Inventory and Planning and Design State Forestry Administration

Freezing and thawing indices are not only of great significance for permafrost research but also are important indicators of the effects of climate ***,to date,research on ground-surface freezing and thawing indices and their relationship with air indices is *** on daily air and ground-surface temperatures collected from 11 meteorological stations in the source region of the Yellow River,the freezing and thawing indices were calculated,and their spatial distribution and trends were *** air-freezing index(AFI),air-thawing index(ATI),ground surface-freezing index(GFI),ground surface-thawing index(GTI),air thawing-freezing index ratio(Na)and surface ground thawing-freezing index ratio(Ng)were 1554.64,1153.93,1.55,2484.85,850.57℃-days and 3.44,*** affected the spatial distribution of the freezing and thawing *** the altitude increased,the freezing indices gradually increased,and the thawing indices and thawing-freezing index ratio *** 1980 to 2014,the AFI and GFI decreased at rates of 8.61 and 11.06℃-days a^(-1),the ATI and GTI increased at 9.65 and 14.53℃-days a^(-1),and Na and Ng significantly increased at 0.21 and 0.79 decade^(-1).Changes in the freezing and thawing indices were associated with increases in the air and ground-surface *** rates of change of the ground surface freezing and thawing indices were faster than the air ones because the rate of increase of the groundsurface temperature was faster than that of the air and the difference between the ground surface and air *** change point of the time series of freezing and thawing indices occurred in 2000–*** 2000–2001,the AFI and GFI were lower than before the change point,and the changing trend was *** ATI,GTI,Na and Ng during 2001–2014 were higher,with faster rates than *** addition,the annual thawing indices composed a greater proportion of the mean annual air temperature and mean annual ground surfac

关键词： Climate change Freezing and thawing indices Permafrost The source region of the Yellow River

Research on the Application of Super Resolution Reconstruction Algorithm for Underwater Image

在线全文

学校读者我要写书评

暂无评论

Computers, materials & Continua 2020年第3期62卷 1249-1258页

作者： Tingting Yang Shuwen Jia hao ma University of Sanya Sanya572000China 1455 Boulevard de maisonneuve O MontréalQC H3G 1M8Canada

Underwater imaging is widely used in ocean,river and lake exploration,but it is affected by properties of water and the *** order to solve the lower-resolution underwater image formed by the influence of water and light,the image super-resolution reconstruction technique is applied to the underwater image *** paper addresses the problem of generating super-resolution underwater images by convolutional neural network framework *** research the degradation model of underwater images,and analyze the lower-resolution factors of underwater images in different situations,and compare different traditional super-resolution image reconstruction *** further show that the algorithm of super-resolution using deep convolution networks(SRCNN)which applied to super-resolution underwater images achieves good results.

关键词： Underwater image image super-resolution algorithm algorithm reconstruction degradation model

Time-domain Finite Element Method for Transient Electric Field and Transient Charge Density on Dielectric Interface

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

CSEE Journal of Power and Energy Systems 2022年第1期8卷 143-154页

作者： Teng Wen Xiang Cui Xuebao Li hao ma Zhibin Zhao State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

This paper is devoted to solving the transient electric field and transient charge density on the dielectric interface under the electroquasistatic(EQS)field conditions with high *** proposed method is suitable for both 2-D and 3-D ***,the governing equations represented by scalar electric potential are discretized by the nodal finite element method(FEM)in space and the finite difference method in ***,the transient constrained electric field equation on the boundary(TCEFEB)is derived to calculate the normal component of the transient electric field intensities on the Dirichlet boundary and dielectric interface as well as the transient charge density on the dielectric ***,a 2-D numerical example is employed to demonstrate the validity of the proposed ***,the comparisons of the numerical accuracy of the proposed method in this paper with the existing FEMs for electric field intensity and charge density on the dielectric interface are *** results show that the numerical accuracy of the proposed method for calculating the normal component of transient electric field intensities on the Dirichlet boundary and dielectric interface as well as the transient charge density on the dielectric interface is close to that of nodal electric potential and an order of magnitude higher than those of existing FEMs.

关键词： Electroquasistatic field composite insulation structure transient constrained electric field equation on the boundary finite element method interface charge time-domain

Single-gait crawling robot:A solution for improving mobility and payload of soft locomotor via simple structure and easy control

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 China(Technological Sciences) 2024年第11期67卷 3626-3628页

作者： ma hao hao TianZe ma JiChao SUN Zhenhao LI Xiang LIU YiBo XIAO HuaPing LIU ShuHai College of Mechanical and Transportation Engineering China University of Petroleum-BeijingBeijing 102249China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education(Tianjin University of Technology) Tianjin 300384China

Motion performance,including movement speed,adaptability to various environments,and load-carrying capability,is crucial for soft crawling robots,tasked with field exploration and the transporting material in often complex and unstructured environments.A wide variety of soft crawling robots,which are driven by electricity[1],chemical power[2],and pressurized fluid[3]to move forward via cyclic deformation,have thus far been inspired by the mobile patterns of soft-bodied animals,such as worms[4],snake[5],octopus[6],*** performance of soft robots in terms of speed and load has developed impressively in recent years.

关键词： robot payload environments