检索结果-南通市图书馆

Efficient Technique for Image Cryptography Using Sudoku Keys

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2023年第10期77卷 1325-1353页

作者： M.A.P.Manimekalai M.Karthikeyan I.Thusnavis Bella Mary K.Martin Sagayam Ahmed A Elngar Unai Fernandez-Gamiz Hatıra Günerhan Department of ECE Karunya Institute of Technology and SciencesCoimbatore641114India Faculty of Computer and Artificial Intelligence Beni-Suef UniversityBeni-Suef62511Egypt Nuclear Engineering and Fluid Mechanics Department University of the Basque CountryBilbao48940Spain Department of Mathematics Faculty of EducationKafkas UniversityKars36100Turkey

This paper proposes a cryptographic technique on images based on the Sudoku *** is a number puzzle,which needs applying defined protocols and filling the empty boxes with *** a small size of numbers as input,solving the sudoku puzzle yields an expanded big size of numbers,which can be used as a key for the Encryption/Decryption of *** this way,the given small size of numbers can be stored as the prime key,which means the key is compact.A prime key clue in the sudoku puzzle always leads to only one solution,which means the key is always *** feature is the background for the paper,where the Sudoku puzzle output can be innovatively introduced in image *** solution is expanded to any size image using a sequence of expansion techniques that involve filling of the number matrix,Linear X-Y rotational shifting,and reverse shifting based on a standard zig-zag *** crypto key for an image dictates the details of positions,where the image pixels have to be *** is made at two levels,namely pixel and sub-pixel(RGB)levels for an image,with the latter having more effective *** brought-out technique falls under the Image scrambling method with partial *** metrics are impressive and are given by a Histogram deviation of 0.997,a Correlation coefficient of 10−2 and an NPCR of 99.98%.Hence,it is evident that the image cryptography with the sudoku kept in place is more efficient against Plaintext and Differential attacks.

关键词： Sudoku image cryptography pixels performance metrics

Magnetic Behaviour of Tb/Si Nanoscale Multilayers with Small Thickness of Rare Earth Layers

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 Letters 2007年第6期24卷 1717-1719页

作者： A.V. Svalov V.O. Vas'kovskiy G.V. Kurlyandskaya J.M. Barandiaran N.N. Schegoleva A.N. Sorokin Ural State University Lenin Avenue 51 620083 Ekaterinburg Russia Universidad del Pals Vasco UPV-EHU Facultad de Ciencias Depto Electricidad yVElectr6nica Apdo. 644'48080 Bilbao Spain Institute of Metal Physics Ural Branch of RAS Kovalevskaya str. 18 620219 Ekaterinburg Russia

We report the magnetic properties of Tb/Si multilayers obtained by rf-sputtering at the Tb layer thickness LTb = 3 nm. Analysis of the magnetization processes indicates more complex behaviour than canonical spinglass transition. It is more probable that these multilayers contain both Tb superparamagnetic particles and Tb-Si spin-glass alloys.

关键词： SPIN-GLASS TRANSITION GD/W MULTILAYERS TERBIUM FILMS NANOPARTICLES

GLOBAL STABILITY OF SIRS EPIDEMIC MODELS WITH A CLASS OF NONLINEAR INCIDENCE RATES AND DISTRIBUTED DELAYS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2012年第3期32卷 851-865页

作者： Yoichi Enatsu Yukihiko Nakata Yoshiaki Muroya Department of Pure and Applied Mathematics Waseda University3-4-1 OhkuboShinjuku-kuTokyo169-8555Japan Basque Center for Applied Mathematics Mazarredo14 E-48009 BilbaoSpain Department of Mathematics Waseda University 3-4-1 OhkuboShinjuku-kuTokyo 169-8555Japan

In this article, we establish the global asymptotic stability of a disease-free equilibrium and an endemic equilibrium of an SIRS epidemic model with a class of nonlin- ear incidence rates and distributed delays. By using strict monotonicity of the incidence function and constructing a Lyapunov functional, we obtain sufficient conditions under which the endemic equilibrium is globally asymptotically stable. When the nonlinear inci- dence rate is a saturated incidence rate, our result provides a new global stability condition for a small rate of immunity loss.

关键词： SIRS epidemic model nonlinear incidence rate global asymptotic stability distributed delays Lyapunov functional

A Robust MPP Tracker Based on Sliding Mode Control for a Photovoltaic Based Pumping System

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2017年第4期14卷 489-500页

作者： Farhat Maissa Oscar Barambones Sbita Lassad Aymen Fleh Department of Electrical Electronics and Communications Engineering American University of Ras A1 Khaimah Ras AI Khaimah 10021 UAE Advanced Control Group Faculty of Engineering of Vitoria-Gasteiz University of the Basque Country Bilbao Spain Electrical and Automatic Engineering Department Engineering School of Gabes University of Gabes Zrig Gabes 6029 Tunisia

In this paper, a mathematical model of the photovoltaic （PV） pumping system＇s main components is firstly established. Then, the design of maximum power point tracking （MPPT） stage that ensures battery charging is described. This work is motivated by the need of photovoltaic generator （PVG） that efficiently extracts maximum power. The PVG is a special source of energy which has nonlinear current-voltage characteristics depending on variations in temperature and solar irradiance. In order to achieve the MPPT operating goals, a special interest is focused on the variable structure sliding mode （SM） control strategy and the classic perturb and observe （P＆O） algorithm. The permanent magnet synchronous motor （PMSM） is selected as a pump driver. The field oriented control is performed as the motor drive strategy. Simulation results show a high level of efficiency, obtained with the proposed PV based pumping system. The performance comparison between SM controller and P＆O controller has been carried out to demonstrate the effectiveness of the former in drawing more energy and a fast response against irradiation disturbances.

关键词： Photovoltaic (PV) pump storage battery boost sliding mode control (SMC) maximum power point tracking (MPPT).

Engineering magnetic nanostructures with inverse hysteresis loops

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nano Research 2016年第8期9卷 2347-2353页

作者： Beatriz Mora Nastassia Soriano Carolina Redondo Alberto Arteche David Navas Rafael Morales Dpto. de Quimica-Fisica Universidad del Pais Vasco UPWEHU 48940 Leioa Spain IFIMUP-IN and Dept. Fisica e Astronomia Universidade do Porto 4169007 Porto Portugal Dpto. de Qulmica-Ffsica & BCMaterials Universidad del Pals Vasco UPV/EHU 48940 Leioa Spain IKERBASQUE Basque Foundation for Science 48011 Bilbao Spain

Top-down lithography techniques allow the fabrication of nanostructured elements with novel spin configurations, which provide a new route to engineer and manipulate the magnetic response of sensors and electronic devices and understand the role of fundamental interactions in materials science. In this study, shallow nanostructure-patterned thin films were designed to present inverse magnetization curves, i.e., an anomalous magnetic mechanism characterized by a negative coercivity and negative remanence. This procedure involved a method for manipulating the spin configuration that yielded a negative coercivity after the patterning of a single material layer. Patterned NiFe thin films with trench depths between 15%-25% of the total film thickness exhibited inverse hysteresis loops for a wide angular range of the applied field and the trench axis. A model based on two exchange-coupled subsystems accounts for the experimental results and thus predicts the conditions for the appearance of this magnetic behavior. The findings of the study not only advance our understanding of patterning effects and confined magnetic systems but also enable the local design and control of the magnetic response of thin materials with potential use in sensor engineering.

关键词： magnetic nanostructures magnetic patterning effects inverted loops negative coercivity negative remanence

TWO TYPES OF CONDITION FOR THE GLOBAL STABILITY OF DELAYED SIS EPIDEMIC MODELS WITH NONLINEAR BIRTH RATE AND DISEASE INDUCED DEATH RATE

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2012年第1期5卷 127-155页

作者： YUKIHIKO NAKATA YOICHI ENATSU YOSHIAKI MUROYA Basque Center for Applied Mathematics Mazarredo 14 E-48009BilbaoSpain Department of Pure and Applied Mathematics Waseda University3-4-10hkubo Shinjuku-ku Tokyo169-8555Japan Department of Mathematics Waseda University 3-4-1 Ohkubo Shinjuku-ku Tokyo 169-8555Japan

We study global asymptotic stability for an SIS epidemic model with maturation delay proposed by K. Cooke, P. van den Driessche and X. Zou, Interaction of maturation delay and nonlinear birth in population and epidemic models, J. Math. Biol. 39（4）（1999） 332-352. It is assumed that the population has a nonlinear birth term and disease causes death of infective individuals. By using a monotone iterative method, we establish sufficient conditions for the global stability of an endemic equilibrium when it exists dependently on the monotone property of the birth rate function. Based on the analysis, we further study the model with two specific birth rate functions BI（N） = be-aN and B3（N） = A/N ＋ c, where N denotes the total population. For each model, we obtain the disease induced death rate which guarantees the global stability of the endemic equilibrium and this gives a positive answer for an open problem by X. Q. Zhao and X. Zou, Threshold dynamics in a delayed SIS epidemic model, J. Math. Anal. Appl. 257（2）（2001） 282-291.

关键词： SIS epidemic models nonlinear birth rate function disease induced deathrate global asymptotic stability the basic reproduction number permanence.

Effect of the Inorganic Nitrogen Source in the Expression of Nitrite Reductase (NirA) in <i>Thermosynechococcus elongatus</i>BP-1

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Microbiology 2014年第15期4卷 1044-1056页

作者： Maite Buxens María J. Llama Juan L. Serra Enzyme and Cell Technology Group Department of Biochemistry and Molecular Biology Faculty of Science and Technology University of the Basque Country (UPV/EHU) Bilbao Spain

Nitrite reductase (NirA, EC 1.***.7.1) from the thermophilic, unicellular, non-N2-fixing cyanobacte-rium Thermosynechococcus elongatus BP-1 has been cloned and expressed in Escherichia coli. Analysis by SDS-PAGE of the pure recombinant protein (His6NirA) showed two protein bands, one of 58 kDa (corresponding to the theoretical His6NirA molecular mass) and another of 44 kDa. Western blotting and mass spectrometry analyses confirmed that the 44 kDa protein resulted from proteolysis of the intact His6NirA, and suggested the existence, at the C-terminal domain of the 58 kDa form, of a region particularly sensible to proteolysis or accessible to proteases. A sample of both forms of His6NirA was used to obtain anti-NirA polyclonal antibodies. These antibodies were used to assess, by SDS-PAGE followed by Western blotting, the in vivo expression of NirA in wild-type cells of T. elongatus BP-1 growing in cultures with nitrate, nitrite or ammonium which were inoculated with cells grown with different nitrogen sources. These analyses revealed that protein bands corresponding to the complete (58 kDa) and truncated (44 kDa) forms of NirA can also be detected in solubilized cells. Moreover, the presence of each of these forms depended on the nitrogen source used to grow cells. Thus, expression of the complete NirA generally predominates in cells growing in medium with nitrate or nitrite. However, the truncated form prevails in cells grown in nitrate or nitrite and then transferred to medium with ammonium. The fact that the patterns of in vivo expression of NirA are different depending on the nitrogen source used possibly relies on a post-translational regulatory mechanism by proteolysis.

关键词： Cyanobacteria NirA Nitrite Reductase Expression Post-Translational Regulation Protein Hydrolysis Thermosynechococcus elongatus BP-1

Self-crystallized Interlayer Integrating Polysulfide-adsorbed TiO2/TiO and Highly-electron-conductive TiO for High-stability Lithium-sulfur Batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2021年第2期37卷 259-264页

作者： YANG Xinzhe QIN Tingting ZHANG Xiaoyu LIU Xiaofei WANG Zizhun ZHANG Wei ZHENG Weitao Key Laboratory of Automobile Materials of Ministry of Education School of Materials Science&EngineeringElectron Microscopy CenterInternational Center of Future ScienceJilin UniversityChangchun130012P.R.China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan430074P.R.China Basque Foundation for Science IKERBASQUEBilbao48013Spain

Low-cost lithium sulfur(Li-S)batteries afford preeminent prospect as a next-generation high-energy storage device by virtue of great theoretical ***,their applications are restricted by some challenging technical barriers,such as weak cycling stability and low poor-conductivity sulfur loading originated in notorious shuttling effect of polysulfide ***,free of any complicated compositing process,we design an interlayer of carbon fiber paper supported TiO2/TiO to impede the shuttle effect and enhance the electrical conductivity via physical isolation and chemical *** a self-crystallized homogeneous interlayer,where TiO2/TiO enables absorbing lithium polysulfides(LiPSs)and TiO plays a key role of high-electron-conductivity exhibited ultrahigh capacities(1000 mA·h/g at 0.5 C and 900 mA·h/g at 1 C)and outstanding capacity retention rate(97%)after 100 ***,our design provides a simple route to suppress the shuttle effect via self-derived evolution Li-S batteries.

关键词： Lithium sulfur battery TiO2/TiO Carbon fiber paper

Mathematical model and energy analysis of ethane dehydration in two-layer packed-bed adsorption

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2019年第6期17卷 33-40页

作者： Yadollah Tavan Seyyed Hossein Hosseini Goodarz Ahmadi Martin Olazar Chemical and Petroleum Engineering Department Sharif University of TechnologyAzadi Av.TehranIran Chemical Engineering Department Faculty of EngineeringIlam University69315-516 IlamIran Department of Mechanical and Aeronautical Engineering Clarkson UniversityPotsdamNY 13699-5725USA Department of Chemical Engineering Faculty of Science and TechnologyUniversity of the Basque CountryP.O.Box 64448080 BilbaoSpain

The 3A zeolites are excellent adsorbents for industrial-scale gas dehydration because of the low energy required for regeneration and ease of operation.A computational study of the dehydration of an industrial feed stream containing ethane and water was performed using an in-house code that included an appropriate equilibrium adsorption *** validated computational model was used to examine the impact of particle size on the process dynamics and the corresponding pressure *** water concentration along the adsorption column was also *** increase the process capacity,the packed adsorption bed was divided into two distinct layers,which were operated with different particle *** length of each layer was determined by a parametric *** best breakthrough time,i.e.,107,800 s,at the allowed pressure drop was obtained when the lengths of the first and second layers were 4.5 and 1 m,*** results showed that the new two-layer adsorption bed could save around 33.8%in total energy requirement in comparison to that of a single bed.

关键词： Molecular sieve Breakthrough Adsorption Ethane dehydration Mathematical model