检索结果-南通市图书馆

Exploration of structural,optical,and photoluminescent properties of (1-x)NiCo_(2)O_(4)/xPbS nanocomposites for optoelectronic applications

引用

Chinese Physics B 2022年第6期31卷 663-670页

作者： Zein K Heiba mohamed Bakr mohamed Noura M Farag ali Badawi Physics Department Faculty of ScienceAin Shams UniversityCairoEgypt Physics Department Faculty of ScienceTaibah UniversityAl-Madina al MunawarahSaudi Arabia Department of Physics College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia Department of Physics University College of TurabahTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia

The(1-x)NiCo_(2)O_(4)/x PbS(0≤x≤0.2)nanocomposite samples are synthesized using the hydrothermal and thermolysis *** different phases developed in the obtained nanocomposite samples are accurately determined using the x-ray diffraction technique equipped with a *** percentage of the formed phases(NiCo_(2)O_(4)(NCO),PbS,PbSO_(4)),structural and microstructure parameters are determined using Rietveld quantitative phase *** transmission electron microscope(TEM)images and Rietveld analysis reveal almost isotropic particle size in the nano range with a very narrow size *** obtained phase percentage of PbS and PbSO4are smaller than nominated values(x)suggesting dissolving of some Pb and S ions into NCO which is then confirmed by the analysis of Fourier-transform infrared(FTIR)spectra of nanocomposite *** absorption spectra are modified upon doping NCO with *** optical band gaps of the nanocomposites increase as the amount of PbS *** effect of alloying on extinction coefficient,refractive index,dielectric constant,optical conductivity,the intensity,and emitted color from the photoluminescence of the nanocomposite samples are also *** refractive index value of NCO and NCO-PbS nanocomposite samples exhibit normal *** photoluminescent measurements reveal that the NCO-PbS nanocomposites can emit a violet *** improvement in the values of the nonlinear optical(NLO)parameters of pristine NCO at high frequencies or the nanocomposite samples at low frequencies,are made them used in NLO photonic devices.

关键词： Co_(2)O_(4)and PbS nanocomposite FTIR optical photoluminescence

来源：

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

Linearly and Quadratically Separable Classifiers Using Adaptive Approach

引用

Journal of Computer Science & Technology 2011年第5期26卷 908-918页

作者： mohamed Abdel-Kawy mohamed ali Soliman Rasha M.Abo-Bakr Department of Computer and Systems Engineering Faculty of EngineeringZagazig UniversityZagazigEgypt Departement of Mathematics Faculty of ScienceZagazig UniversityZagazigEgypt

This paper presents a fast adaptive iterative algorithm to solve linearly separable classification problems in R *** each iteration,a subset of the sampling data （n-points,where n is the number of features） is adaptively chosen and a hyperplane is constructed such that it separates the chosen n-points at a margin and best classifies the remaining *** classification problem is formulated and the details of the algorithm are ***,the algorithm is extended to solving quadratically separable classification *** basic idea is based on mapping the physical space to another larger one where the problem becomes linearly *** illustrations show that few iteration steps are sufficient for convergence when classes are linearly *** nonlinearly separable data,given a specified maximum number of iteration steps,the algorithm returns the best hyperplane that minimizes the number of misclassified points occurring through these *** with other machine learning algorithms on practical and benchmark datasets are also presented,showing the performance of the proposed algorithm.

关键词： linear classification quadratic classification iterative approach adaptive technique

来源：

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

Robust Output Practical Stability of Time-Varying Nonlinear Control Systems via Indefinite Lyapunov Functions

引用

Journal of Systems Science & Complexity 2024年第6期37卷 2595-2613页

作者： DAMAK Hanen ABOTHHER Amal HAMMAMI mohamed ali Department of Mathematics University of SfacPreparatory Engineering Institute of SfaxSfax 3047Tunisia Department of Mathematics University of ZawiaFaculty of education Abu EssaZawia 16418Libya Department of Mathematics University of SfacFaculty of Sciences of SfaxSfax 3047Tunisia

This paper focuses on studying the problem of robust output practical stability of timevarying nonlinear control systems. The main innovation lies in the fact that the proposed approach for stability analysis allows for the computation of bounds that characterize the asymptotic convergence of solutions to a small ball centered at the origin using a Lyapunov method with a definite *** different conditions on the perturbation, the authors demonstrate that the system can be globally robustly asymptotically output stable by designing a candidate feedback controller. Finally, three examples are given to illustrate the practical implications and significance of the theoretical results.

关键词： Control theory global robust practical asymptotic output stability(GRPAOS) Lyapunov method time-varying control systems

来源：

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

A Multi-Level Selective Maintenance Strategy Combined to Data Mining Approach for Multi-Component System Subject to Propagated Failures

引用

Journal of Systems Science and Systems Engineering 2022年第3期31卷 313-337页

作者： mohamed ali Kammoun Zied Hajej Nidhal Rezg Universite de Lorraine LGIPMF-57000 MetzFrance Ecole poly technique du Groupe Honoris United Universities-Tunisia

In several industrial fields like air transport,energy industry and military domain,maintenance actions are carried out during downtimes in order to maintain the reliability and availability of production *** such a circumstance,selective maintenance strategy is considered the reliable solution for selecting the faulty components to achieve the next mission without *** this paper,a novel multi-level decision making approach based on data mining techniques is investigated to determine an optimal selective maintenance *** the first-level,the age acceleration factor and its impact on the component nominal age are used to establish the local *** first decision making employed K-means clustering algorithm that exploited the historical maintenance *** on the first-level intervention plan,the remaining-levels identify the stochastic dependence among components by relying upon Apriori association rules algorithm,which allows to discover of the failure occurrence *** addition,at each decision making level,an optimization model combined to a set of exclusion rules are called to supply the optimal selective maintenance plan within a reasonable time,minimizing the total maintenance cost under a required reliability *** illustrate the robustness of the proposed strategy,numerical examples and a FMS real study case have been solved.

关键词： Selective maintenance stochastic dependence age acceleration factor data mining flexible manufacturing system

来源：

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

ON A SECOND ORDER DISSIPATIVE ODE IN HILBERT SPACE WITH AN INTEGRABLE SOURCE TERM

引用

Acta Mathematica Scientia 2012年第1期32卷 155-163页

作者： Alain Haraux mohamed ali Jendoubi UPMC Univ Paris 06 UMR 7598Laboratoire Jacques-Louis Lions CNRS UMR 7598Laboratoire Jacques-Louis Lions Facult des Sciences de Bizerte Dpartement de Mathmatiques

Asymptotic behaviour of solutions is studied for some second order equations including the model casex（t）＋γx（t）＋ ↓△φb（x（t）） = h（t） with γ 〉 0 and h ∈ L1（O, ＋∞; H）, φ being continuouly differentiable with locally Lipschitz continuous gradient and bounded from below. In particular when φ is convex, all solutions tend to minimize the potential φ as time tends to infinity and the existence of one bounded trajectory implies the weak convergence of all solutions to equilibrium points.

关键词： dissipative dynamical system asymptotic behaviour gradient system heavyball with friction

来源：

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

Investigation for Uranium Dispersion Adjacent to Cretaceous Phosphatic Outcrops in Al-Nassrieh Basin, Southern Palmyrides, Syria

引用

Journal of Earth Science 2016年第5期27卷 786-795页

作者： mohamed Al-Hilal Ahmad Al-ali Department of Geology the Atomic Energy Commission of Syria (AECS)

A detailed radiometric survey including soil gas radon measurements and field gammaray survey, in accordance with geochemical and geological investigations were carried out in AlNassrieh Basin（central Syria）, for the purpose of uranium exploration. Thirty-six samples were collected from various lithofacies of the survey area and analyzed by γ-ray spectrometric technique for determining the concentration values of major radioelements. The relationships between the concentrations of equivalent e U, e Th, and their ratios were examined in order to define their trend of variations and evaluate the degree of uranium remobilization and redistribution. Although the initial results indicate that uranium enrichment is mostly restricted to the Upper Cretaceous phosphate rocks, a considerable portion of uranium appeared to be leached out of the primary phosphatic source and dispersed in the adjacent recent sediments. Further, notable increases of radon level associated with relatively high values of uranium concentration and gamma count rates were found to be spatially correlated with the transition zone between the marine Paleogene and continental Neogene formations throughout the study basin. This observation demonstrates the importance of the concerned zone as a suitable geological environment for hosting probable uranium mineralization along a chemically reducing interface where surface water of terrestrial and marine origin mingled at depth and away from surficial conditions.

关键词： radiometric survey geochemistry uranium exploration AI-Nassrieh Basin Syria.

来源：

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

Thermal degradation of diethanolamine at stripper condition for CO2 capture: Product types and reaction mechanisms

引用

Chinese Journal of Chemical Engineering 2019年第12期27卷 2900-2908页

作者： Idris mohamed Saeed Brahim Si ali Badrul mohamed Jan Wan Jefrey Basirun Shaukat ali Mazari Ibrahim ali Obid Birima Department of Chemistry Faculty of ScienceUniversity of MalayaKuala Lumpur 50603Malaysia Department of Chemical Engineering Faculty of EngineeringUniversity of MalayaKuala Lumpur 50603Malaysia Department of Chemical Engineering Faculty of EngineeringDawood University of Engineering and TechnologyMA Jinnah RoadKarachi 74800Pakistan

Amine-based absorption/stripping is one of the promising technology for CO2 capture from natural and industrial gas *** the process,amines and CO2 undergo irreversible reactions to produce undesired compounds,which cause corrosion,foaming,increased viscosity and breakdown of equipment,ultimately contributing to the economic loss and environmental *** this study,the thermal degradation of aqueous diethanolamine in the presence and absence of dissolved CO2 was *** experiments were performed in stainless steel *** results show that thermal degradation in the absence of CO2 was a slow process;triethanolamine,and tris(2-aminoethyl)amine were only the degradation products identified in the mixture In addition,the rate of degradation was very low,only 3%degradation was observed after 4 *** in the presence of CO2,sixteen degradation products were identified,nine of which were new degradation products reported for the first time in this *** 3-(2-hydroxyethyl)-2-oxazolidinone,1,4-bis(2-hydroxyethyl)piperazine and triethanolamine were the most abundant degradation *** remaining DEA concentration after 4 weeks was about 20%of the total amine *** most probable degradation reactions and their mechanisms are also proposed.

关键词： Diethanolamine CO2 capture Degradation Mechanism

来源：

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

Dengue virus infections and anti-dengue virus activities of Andrographis paniculata

引用

Asian Pacific Journal of Tropical Medicine 2020年第2期13卷 49-55页

作者： mohamed ali-Seyed Kavitha Vijayaraghavan Department of Clinical Biochemistry Faculty of MedicineUniversity of TabukTabukSaudi ArabiaTabuk 71491Saudi Arabia Department of Chemical Engineering Agni College of TechnologyChennaiTamil NaduIndia

Dengue is a debilitating disease that poses a perpetual threat to human health and increases the global economic burden every *** advances in medical sciences,dengue virus(DENV)infects approximately 200 million people every *** date,no effective antiviral is valiable to treat DENV in individuals despite great efforts in accomplishing these *** approaches have been used in the search for dengue antiviral like screening of combinatorial compounds against DENV enzymes and structurebased computational *** recent years,investigators have turned their focus into medicinal plants,trying to identify compounds that can be used as dengue *** represents a great reservoir of potential substances that can be explored with the aim of discovering new drugs that can be either used directly as pharmaceuticals or can provide drug leads,which can be scrutinized further for the development of new anti-dengue natural *** previous investigations have dealt with numerous plant extracts or bioactive principles for their antiviral property as they normally considered being safer when compared to synthetic *** paniculata belongs to family Acanthaceae and is generally known as‘king of bitters’.Diverse bioactive compounds from this plant such as diterpenes,flavonoids,xanthones,noriridoides and other miscellaneous compounds have exhibited their potential as therapeutics for various chronic as well as infectious *** review is based on literature review on scientific journals,books and electronic sources,which highlights the pathogenesis of DENV and describe an assortment of bioactive principles that have been possessing antiviral potential,which include dengue and discuss the therapeutic efficacy and mechanism of action of Andrographis ***,a detailed and more comprehensive clinical trial on mammalian tissues and organs is needed in future studies.

关键词： Andrographis paniculata Dengue Phytochemicals Natural products Andrographolide

来源：

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

Grey Wolf-Based Method for an Implicit Authentication of Smartphone Users

引用

Computers, Materials & Continua 2023年第5期75卷 3729-3741页

作者： Abdulwahab ali Almazroi mohamed Meselhy Eltoukhy University of Jeddah College of Computing and Information Technology at KhulaisDepartment of Information TechnologyJeddahSaudi Arabia

Smartphones have now become an integral part of our everyday *** authentication on smartphones is often accomplished by mechanisms(like face unlock,pattern,or pin password)that authenticate the user’s *** technologies are simple,inexpensive,and fast for repeated ***,these technologies are still subject to assaults like smudge assaults and shoulder ***’touch behavior while using their cell phones might be used to authenticate them,which would solve the *** performance of the authentication process may be influenced by the attributes chosen(from these behaviors).The purpose of this study is to present an effective authentication technique that implicitly offers a better authentication method for smartphone usage while avoiding the cost of a particular device and considering the constrained capabilities of *** began by concentrating on feature selection methods utilizing the grey wolf optimization *** random forest classifier is used to evaluate these *** testing findings demonstrated that the grey wolf-based methodology works as a better optimum feature selection for building an implicit authentication mechanism for the smartphone environment when using a public *** achieved a 97.89%accuracy rate while utilizing just 16 of the 53 characteristics like utilizing minimum mobile resources mainly;processing power of the device and memory to validate ***,the findings revealed that our approach has a lower equal error rate(EER)of 0.5104,a false acceptance rate(FAR)of 1.00,and a false rejection rate(FRR)of 0.0209 compared to the methods discussed in the *** promising results will be used to create a mobile application that enables implicit validation of authorized users yet avoids current identification concerns and requires fewer mobile resources.

关键词： Smartphone authentication implicit authentication grey wolf random forest feature selection

来源：

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

Impact of composition ratio on the structure and optical properties of(1-x)MnFe_(2)O_4/(x)ZnMn_(2)O_4 nanocomposite

引用

Chinese Physics B 2022年第7期31卷 481-489页

作者： Zein K.Heiba mohamed Bakr mohamed ali A.Alkathiri Sameh I.Ahmed A A Alhazime Department of Physics Faculty of ScienceAin shams UniversityCairo 11566Egypt Physics Department Faculty of ScienceTaibah UniversityAl-Madina al MunawarahSaudi Arabia Depatment of Physics College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia

(1-x)MnFe_(2)O_(4)(MFO)/xZnMn_(2)O_(4)(ZMO)(x=0,0.2,0.5,0.8,and 1.0)nanocomposite samples were prepared using co-precipitation *** phase percentage,cell parameters,and crystallite size of MFO and ZMO phases in each nanocomposite sample were calculated using Rietveld refinement *** x-ray diffraction(XRD)analysis and Fourier-transform infrared spectroscopy techniques established the variation in the lattice parameters of each phase are due to permutation of all cations among the octahedral and tetrahedral sites of MFO and *** different oxidation states of different ions in all samples were determined using x-ray photoelectron spectroscopy(XPS)*** variation in absorbance of the nanocomposite samples with composition parameter(x)is dependent on the wavelength *** optical bandgap of the nanocomposite samples is decreased as the content of ZMO phase *** effect of alloying on the refractive index,extinction coefficient,dielectric constant,optical conductivity,and the nonlinear optical behaviors of all samples were studied in *** nanocomposite sample x=0.5 disclosed upgraded optical parameters with the highest refractive index,optical conductivity,and PL intensity,which nominate it to be functional in various application fields.

关键词： MFO and ZMO composite XPS structure optical

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：