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Chinese Physics Letters 2014年第9期31卷 61-64页

作者： r. Z. r. r. rosdin F. Ahmad n. M. Ali r. M. nor n. r. Zulkepely S. W. Harun H. Arof Department of Electrical Engineering University of Malaya Kuala Lumpur 50603 Malaysia Engineering Universiti Teknologi Malaysia Kuala -Lumpur 54100 Malaysia Physics Department University of Malaya Kuala Lumpur 50603 Malaysia

We present a simple, compact and low-cost mode-locked erbium-doped fiber laser （EDFL） using single-wMled carbon nanotubes （SWCnTs） embedded in a poly-ethylene oxide （PEO） thin film as a passive saturable absorber. The film is fabricated by using a prepared homogeneous SWCnT solution, which is mixed with a diluted PEO solution and cast onto a glass Petri dish to form, by evaporation, a thin film. The 50 μm-thick film is sandwiched between two fiber connectors to construct a saturable absorber, which is then integrated in an EDFL cavity to generate self-started stable soliton pulses operating at 1560.8nm. The soliton pulse starts to lase at a pump power threshold of 12.3mW with a repetition rate of 11.21MHz, a pulse width of 1.02ps, an average output power of 0.65 mW and a pulse energy of 57.98pJ.

关键词： SOLITOnS rESEArCH FIBEr lasers SInGLE walled carbon nanotubes ErBIUM POLYETHYLEnE oxide THIn films -- research

Secret Image Communication Scheme Based on Visual Cryptography and Tetrolet Tiling Patterns

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Computers, Materials & Continua 2020年第11期65卷 1283-1301页

作者： n.rajeshKumar DYuvaraj G.Manikandan r.BalaKrishnan B.Karthikeyan D.narasimhanand n.r.raajan Srinivasa ramanujan Centre SASTRA Deemed UniversityKumbakonamTamil NaduIndia Department of Computer Science Cihan University-DuhokDuhokIraq School of Computing SASTRA Deemed UniversityThanjavurTamil NaduIndia School of EEE SASTRA Deemed UniversityThanjavurTamil NaduIndia

Visual cryptographic scheme is specially designed for secret image sharing in the form of shadow *** basic idea of visual cryptography is to construct two or more secret shares from the original image in the form of chaotic *** this paper,a novel secret image communication scheme based on visual cryptography and Tetrolet tiling patterns is *** proposed image communication scheme will break the secret image into more shadow images based on the Tetrolet tiling *** secret image is divided into 4×4 blocks of tetrominoes and employs the concept of visual cryptography to hide the secret *** main feature of the proposed scheme is the selection of random blocks to apply the tetrolet tilling patterns from the fundamental tetrolet pattern *** procedure is used to perform both tetrolet transform and the scheme of visual ***,the experimental results showcase the proposed scheme is an extraordinary approach to transfer the secret image and reconstruct the secret image with high visual quality in the receiver end.

关键词： Tetrominoes tile visual secret share image transmission security visual cryptography

Using HF rather than nH_4F as doping source for spray-deposited SnO_2:F thin films

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Journal of Central South University 2012年第3期19卷 791-796页

作者： S.J.Ikhmayies r.n.Ahmad-Bitar Department of Basic Sciences-Physics Faculty of Information TechnologyAl Isra University Physics Department Faculty of ScienceUniversity of Jordan

Fluorine doped tin oxide SnO2：F thin films were prepared by the spray pyrolysis （SP） technique on glass substrates by using SnC12.2H2O as a precursor and nH4F and HF as doping compounds. A comparison between the properties of the films obtained by using the two doping compounds was performed by using I-V characteristics in the dark at room temperature, AC measurements, and transmittance. It is found that the films prepared by using HF have smaller resistivity, lower impedance and they are less capacitive than films prepared by using nH4F. In addition, these films have higher transmittance, higher optical bandgap energy and narrower Urbach tail width. These results are interesting for the use of SnO2：F as forecontact in CdS/CdTe solar cells.

关键词： CdS/CdTe solar cells transparent conducting oxides spray pyrolysis doping

Development of lead-free multifunctional materials Bi(Co_(0.45Ti0.45Fe0.10)O3

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Progress in natural Science:Materials International 2018年第3期28卷 308-314页

作者： nitin Kumar Alok Shukla r.n.P.Choudhary Department of Physics National Institute of Technology Mizoram Department of Physics Siksha ‘O′Anusandhan University

A lead free multiferroic material,Bi(Co0.45Ti0.45Fe0.10)O3（BCTF45/10）was synthesized by a solid-state reaction route at high ***45/10 powder was prepared using appropriate raw maretials in oxide powders with methanol ***-prepared circular shaped pellets were sintered at 1053 K for 6 h to produce a compact *** structural properties and elemental analysis were determined using X-ray diffraction and energy-dispersive X-ray spectroscopy techniques respectively at room *** microstructure or surface morphology of the sintered sample was carried out by using field emission scanning electron microscope（FE-SEM）.The XrD analysis shows that the compound exhibits the single-phase of orthorhombic *** average crystallite size estimated using the Scherrer's technique was found to be 30 *** influence of Co and Ti substitution（at Bi and Ti sites of Bi Fe O3）on some physical and electrical properties of Bi Fe O3was examined by using phase sensitive multimeter in a wide frequency and temperature *** magnetic nature of the sample was studied using vibrating sample *** of room temperature magnetic hysteresis loop exhibits the enhanced ferromagnetic characteristic with saturation magnetization of 5.091 emu/g and coercive field of 0.213 k Oe *** enhanced magnetic properties highlight various potential applications of Co/Ti doped BCTF45/10 materials.

关键词： Multifunctional material Dielectric constant and loss Electrical characteristics Impedance spectroscopy

AC measurements of spray-deposited CdS:In thin films

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Journal of Central South University 2012年第3期19卷 829-834页

作者： S.J.Ikhmayies r.n.Ahmad-Bitar Department of Basic Sciences-Physics Faculty of Information TechnologyAl Isra University Physics Department Faculty of ScienceUniversity of Jordan

Indium doped cadmium sulfide thin films （CdS：In） were produced by the spray pyrolysis technique on glass substrates. AC measurements were used to investigate the electrical properties of the films depending on Brick-layer model for polycrystalline materials. The measurements were performed at room temperature in the dark and room light in the frequency range from 20 Hz to 1 MHz using coplanar indium electrodes. The data were analyzed by using Bode plots for the impedance Z and dielectric loss tang with frequencyf It is found that the impedance has no dependence on frequency in the low frequency region but has 1/f dependence in the high frequency region. One dielectric loss peak is obtained, which means the presence of a single relaxation time, and hence the films are modeled by just one rC circuit which represents the grains. This means that there is just one conduction mechanism that is responsible for the conduction in the bulk, due to electronic transport through the grains. real values of the impedance in the low frequency region and relaxation times for treated and as-deposited fihns were estimated.

关键词： II-VI compounds spray pyrolysis impedance dielectric loss Bode plots

Multipliers on Vector-valued L^1-spaces for Hypergroups

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Acta Mathematica Sinica,English Series 2018年第7期34卷 1059-1073页

作者： r.SArMA n.Shravan KUMAr Vishvesh KUMAr Department of Mathematics Indian Institute of Technology Delhi

In this article, we extend the well known Wendel＇s theorem to the context of vector-valued L1-spaces on hypergroups. In this regard, various cases have been studied.

关键词： Vector-valued Ll-spaces hypergroups multipliers translation invariant operators Fouriertransform

A hydrochemical and Dye-tracing Investigation in the Posht-e-naz Karstic Aquifer,Alburz Mountain,northern Iran

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Journal of Mountain Science 2011年第1期8卷 37-45页

作者： Kalantari n. Alizadeh B. Mohammadi A.r. Keshavarzi.M.r. Geology Department Shahid Chamran University Waterresource Organization

A hydrochemical and tracer study （uranine injection） was conducted in Jurassic limestone of the Posht-e-naz area in the Alborz belt to evaluate hydraulic relations between a large diameter （about 100m） sinkhole and springs and aquifer parameters. A main goal of the project was to find out the source of turbidity of the Emarate drinking water supply spring （SP4） in rainy season. Springs discharge were measured and hydrochemical investigation were carried out. The uranine tracer was injected and eight springs, three wells and the neka river were selected and totally 989 samples in 107 days were collected. Hydrochemical data demonstrated a relative connection between sinkhole （Shl） and spring （SP4）. The results of the tracing by sampling water indicated only a hydraulic connection between Sange- nou spring （SP8） and injection point, while the charcoal packets analysis revealed tracer exits from spring numbers SP1, SP3, SP4, SP5, SP8, in wells W1 and W2, and in the neka river. The concentration - time curves of charcoal packets for qualitative analysis and exit tracer for quantitative analysis is also assessed.

关键词： Posht-e-naz Tracing Spring Sinkhole Charcoal packet

Effects of Impurity on Microstructure and Hardness in Pure Al Subjected to Dynamic Plastic Deformation at Cryogenic Temperature

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Journal of Materials Science & Technology 2011年第7期27卷 628-632页

作者： F. Huang n.r. Tao K. Lu Shenyang national Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Microstructure and hardness were investigated in pure Al samples with different purities （5n： 99.999%, 4n： 99.993%, and 2n： 99.7% in weight） subjected to dynamic plastic deformation at cryogenic temperatures. The saturated sizes of refined grains/subgrains in these samples induced by plastic deformation are about 240 nm without an obvious impurity effect, but the dislocation density in 2n Al is evidently higher than that in other samples. Boundary misorientations for 5n and 4n Al are below 10° with average values of 2–3°, while the average misorientation for 2n Al is obviously larger, being about 14°. Microhardness of LnT-DPD 2n Al is higher than that of 5n and 4n Al, owing to the enhanced dislocation density as their grain/subgrain sizes are almost identical.

关键词： Aluminum Impurity nanostructure Grain refinement

Enhanced Trust Based Access Control for Multi-Cloud Environment

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Computers, Materials & Continua 2021年第12期69卷 3079-3093页

作者： n.r.rejin Paul D.Paul raj Technology PuduvoyalGummidipoondi601206India r M D Engineering College KavaraipettaiGummidipoondi601206India

Security is an essential part of the cloud *** ensuring the security of the data being communicated to and from the cloud server,a significant parameter called trust was ***-based security played a vital role in ensuring that the communication between cloud users and service providers remained unadulterated and *** most cloud-based data distribution environments,emphasis is placed on accepting trusted client users’requests,but the cloud servers’integrity is seldom *** paper designs a trust-based access control model based on user and server characteristics in a multi-cloud environment to address this *** proposed methodology consists of data encryption using Cyclic Shift Transposition Algorithm and trust-based access control *** this trust-based access control mechanism framework,trust values are assigned to cloud users using direct trust *** direct trust degree is estimated based on the following metrics:success and failure rate of interactions,service satisfaction index,and dishonesty *** addition to this,trust values are assigned to cloud servers based on the metrics:server load,service rejection rate,and service access *** role-Based Access control policy of each user is modified based on his trust *** the server fails to meet the minimum trust level,then another suitable server will be *** proposed system is found to outperform other existing systems in a multi-cloud environment.

关键词： Cloud computing trust access control cloud service provider cloud data user CSTA

Charged grain boundary transitions in ionic ceramics for energy applications

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npj Computational Materials 2019年第1期5卷 947-958页

作者： K.S.n.Vikrant r.Edwin García School of Materials Engineering Purdue UniversityWest LafayetteIN 47907USA

Surfaces and interfaces in ionic ceramics play a pivotal role in defining the transport limitations in many of the existing and emerging applications in energy-related systems such as fuel cells,rechargeable batteries,as well as advanced electronics such as those found in semiconducting,ferroelectric,and piezotronic ***,a variational framework has been developed to understand the effects of the intrinsic and extrinsic ionic species and point defects on the structural and electrochemical stability of grain boundaries in polycrystalline *** theory predicts the conditions for the interfacial electrochemical and structural stability and phase transitions of charged interfaces and quantifies the properties induced by the broad region of electrochemical influence in front of a grain boundary capable of spanning anywhere from a few angtroms to entire *** demonstrate the validity of this theory for Y_(x)Zr_(1−x)O_(2−x/2),cubic yttria stabilized zirconia.

关键词： ceramics grain transitions