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Identification of the normal and abnormal glow discharge modes in a neon-xenon gas mixture at low pressure

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Plasma Science and Technology 2018年第11期20卷 70-75页

作者： b HECHELEF A bOUCHIKHI University of Saida Faculty of Technology Department of Electrical Engineering Saida 20000 Algeria

In this paper, we focused on the identification of the normal and abnormal glow discharge modes in a neon-xenon gas mixture at low pressure. We considered four gas mixtures： 90%Ne-10%Xe, 80%Ne-20%Xe, 70%Ne-30%Xe and 50%Ne-50%Xe at 1.5 Torr. The range of the gap voltage is 150-500 V. A one-dimensional fluid model with multiple species was used in this work, and the metastable state of the atoms as well as the radiation effects were integrated into the model too. The input data changed for each percentage in the gas mixture, and was calculated by bOLSIG＋ software. The parameters of particle transport and their rate coefficients strictly depend on the mean electron energy. The results show that the neon ion density is negligible compared to the xenon ion density, mostly in the case of 50%Ne-50%Xe.

关键词： gas mixtures boltzmann's equation Poisson's equation blanc's law two-order fluid model

Oscillating multidromion excitations in higher-dimensional nonlinear lattice with intersite and external on-site potentials using symbolic computation

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Chinese Physics b 2014年第1期23卷 98-107页

作者： b. Srividya louiskavitha@yahoo.co.in Department of Chemistry Periyar University Salem 636 011 India

We show by an extensive method of quasi-discrete multiple-scale approximation that nonlinear multi-dimensional lattice waves subjected to intersite and external on-site potentials are found to be governed by （N＋ 1 ）-dimensional nonlinear Schr6dinger （NLS） equation. In particular, the resonant mode interaction of （2＋l）-dimensional NLS equation has been identified and the theory allows the inclusion of transverse effect. We apply the exponential function method to the （2＋ I ）- dimensional NLS equation and obtain the class of soliton solutions with a purely algebraic computational method. Notably, we discuss in detail the effects of the external on-site potentials on the explicit form of the soliton solution generated recursively. Under the action of the external on-site potentials, the model presents a rich variety of oscillating multidromion patterns propagating in the system.

关键词： solitons partial differential equations lattice dynamics exact solutions

Pattern Analysis and Regressive Linear Measure for botnet Detection

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Computer Systems Science & Engineering 2022年第10期43卷 119-139页

作者： b.Padmavathi b.Muthukumar Department of Computer Science and Engineering Sathyabama Institute of Science and TechnologyChennaiIndia Department of Computer Science and Engineering Easwari Engineering CollegeChennaiIndia Department of Computer Science and Engineering United Institute of TechnologyCoimbatoreIndia

Capturing the distributed platform with remotely controlled compromised machines using botnet is extensively analyzed by various ***,certain limitations need to be addressed *** provisioning of detection mechanism with learning approaches provides a better solution more broadly by saluting multi-objective *** bots’patterns or features over the network have to be analyzed in both linear and non-linear *** linear and non-linear features are composed of high-level and low-level *** collected features are maintained over the bag of Features(boF)where the most influencing features are collected and provided into the classifier ***,the linearity and non-linearity of the threat are evaluated with Support Vector Machine(SVM).Next,with the collected boF,the redundant features are eliminated as it triggers overhead towards the predictor ***,a novel Incoming data Redundancy Elimination-based learning model(RedE-L)is built to classify the network features to provide robustness towards botNets *** simulation is carried out in MATLAb environment,and the evaluation of proposed RedE-L model is performed with various online accessible network traffic dataset(benchmark dataset).The proposed model intends to show better tradeoff compared to the existing approaches like conventional SVM,C4.5,RepTree and so ***,various metrics like Accuracy,detection rate,Mathews Correlation Coefficient(MCC),and some other statistical analysis are performed to show the proposed RedE-L model's *** F1-measure is 99.98%,precision is 99.93%,Accuracy is 99.84%,TPR is 99.92%,TNR is 99.94%,FNR is 0.06 and FPR is 0.06 respectively.

关键词： botNet threat intrusion features linearity and non-linearity redundancy regressive linear measure classification redundancy eliminationbased learning model

On the pressure and stress singularities induced by steady flows of a pair of nonmiscible,incompressible,viscous fluids contacting a wall with slip

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Acta Mechanica Sinica 2020年第3期36卷 686-691页

作者： G.b.Sinclair Department of Mechanical Engineering Louisiana State UniversityBaton RougeLA 70803USA

An earlier asymptotic analysis identified the flow-induced power and log singularities present when two nonmiscible,incompressible,viscous fluids contact a wall with no slip *** a parallel asymptotic analysis identifies such singularities in pressures and stresses when slip is *** the singularity exponents for the two types of contact conditions are similar,the angles of interface impingement that have either power or log singularities are usually quite distinct.

关键词： Incompressible viscous fluids Slip conditions Fluid-structure interactions Singular stresses

The P-Median Problem： A Tabu Search Approximation Proposal Applied to Districts

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Journal of Mathematics and System Science 2015年第3期5卷 100-112页

作者： Maria beatriz bernabe Loranca Rogelio Gonzalez Velfizquez Martin estrada Analco Facultad de Ciencias de la Computacion Benemerita Universidad Autenoma de Puebla Puebla Mexico

P-median is one of the most important Location-Allocation problems. This problem determines the location of facilities and assigns demand points to them. The p-median problem can be established as a discrete problem in graph terms as： Let G = （V, E） be an undirected graph where V is the set of n vertices and E is the set of edges with an associated weight that can be the distance between the vertices dij= d（vi, Vj） for every i, j =1,...,n in accordance to the determined metric, with the distances a symmetric matrix is formed, finding Vp∈ V such that ｜ Vp｜∈ = p, where p can be either variable or fixed, and the sum of the shortest distances from the vertices in {V-Vp} to their closet vertex in Vp is reduced to the minimum. Under these conditions the P-median problem is a combinatory optimization problem that belongs to the NP-hard class and the approximation methods have been of great aid in recent years because of this. In this point, we have chosen data from OR-Library [1] and we have tested three algorithms that have given good results for geographical data （Simulated Annealing, Variable Neighborhood Search, bioinspired Variable Neighborhood Search and a Tabu Search-VNS Hybrid （TS-VNS）. However, the partitioning method PAM （Partitioning Around Medoids）, that is modeled like the P-median, attained similar results along with TS-VNS but better results than the other metaheuristics for the OR-Library instances, in a favorable computing time, however for bigger instances that represent real states in Mexico, TS-VNS has surpassed PAM in time and quality in all instances. In this work we expose the behavior of these five different algorithms for the test matrices from OR-Library and real geographical data from Mexico. Furthermore, we made an analysis with the goal of explaining the quality of the results obtained to conclude that PAM behaves with efficiency for the OR-Library instances but is overcome by the hybrid when applied to real instances. On the other hand we have

关键词： Metaheuristcs P-mediana PAM Tabu search.

The synthesis of polymers of intrinsic microporosity (PIMs)

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Science China Chemistry 2017年第8期60卷 1023-1032页

作者： Neil b.McKeown School of Chemistry University of Edinburgh David Brewster Road Edinburgh EH9 3F J U

Polymers of intrinsic microporosity （PIMs） are a class of porous organic polymer （POP） that form microporous solids due to the inefficient packing of their rigid and contorted macromolecular chains. In contrast to other types of POP, PIMs are not comprised of a network of cross-linked covalent bonds so that they can be dissolved in organic solvents and processed into robust films, coatings or fibres. Here, over twelve years＇ accumulated research on the synthesis of PIMs is reviewed. To date, three types of polymerisation reaction have been used successfully to prepare PIMs of sufficient molecular mass to form robust self-standing films. These involve the formation of dibenzodioxin, Tr6ger＇s base and imide linkages between monomeric units. This rapid development of synthetic methods for preparing PIMs has been driven by their rich potential for numerous diverse applications and this synergistic relationship between synthesis and functionality is set to continue.

关键词： polymers of intrinsic microporosity synthesis porous organic polymers

Non-native plant species richness and influence of greenhouses and human populations in the conterminous United States

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Ecological Processes 2023年第1期12卷 388-401页

作者： brice b.Hanberry USDA Forest Service Rocky Mountain Research StationRapid CitySD 57702USA

background One issue in invasive plant ecology is identification of the factors related to the invasion process that increase number of non-native *** invasion by non-native species increases,so does the probability that some non-native species will become harmful,or classified as invasive species,which disrupt natural ecosystems with attendant economic and social costs.I quantified patterns of how non-native species richness varied with vegetation types and human *** evaluate the relative importance of different predictor variables for invasion pathways in the conterminous United States,I modeled non-native plant species richness by county compared to current and historical human populations;greenhouses and nurseries;railroads,pipelines,transmission lines,and oil and gas wells;and land covers of impervious surface,development intensity categories,agriculture,and vegetation types.I also modeled these variables within vegetation types,excluding vegetation *** To summarize patterns,non-native plant species richness increased from 72 to 200 with increasing human population density *** and forest land use mosaics had the greatest mean number of non-native plant species,ranging from 121 to 166,whereas grasslands and grassland mosaics had the least number of non-native plant species,about *** modeling variable importance,all combined variables had R^(2)values of 56%(random forests regressor)and 54%(cubist regressor)for predictions of withheld observations of non-native plant species rich-ness,with greenhouse density and percent forestlands as most influential *** variables of greenhouses(R^(2)=29%),historical and current human populations(R^(2)=27%and 23%),impervious surface(25%),and medium intensity development(23%)were most associated with non-native plant species *** vegetation types,greenhouse and historical human population densities were influential variables particularly in forestlands,shrubland

关键词： Agriculture Energy Forest Grassland Invasive Propagule Rural Transport Urban

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Axial magnetic field effect in numerical analysis of high power Cherenkov free electron laser

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Chinese Physics b 2019年第6期28卷 176-183页

作者： F bazoubAND b Maraghechi Department of Physics Fasa UniversityPost code 74616-86131FasaIran Department of Physics Manhattanville CollegePurchaseNew York 10577USA

Cherenkov free electron laser(CFEL) is simulated numerically by using the single particle method to optimize the electron beam. The electron beam is assumed to be moving near the surface of a flat dielectric slab along a growing radiation. The set of coupled nonlinear differential equations of motion is solved to study the electron dynamics. For three sets of parameters, in high power CFEL, it is found that an axial magnetic field is always necessary to keep the electron beam in the interaction region and its optimal strength is reported for each case. At the injection point, the electron beam’s distance above the dielectric surface is kept at a minimum value so that the electrons neither hit the dielectric nor move away from it to the weaker radiation fields and out of the interaction region. The optimal electron beam radius and current are thereby calculated. This analysis is in agreement with two previous numerical studies for a cylindrical waveguide but is at odds with analytical treatments of a flat dielectric that does not use an axial magnetic field. This is backed by an interesting physical reasoning.

关键词： Cherenkov free electron laser axial magnetic field flat dielectric slab electron beam

Effect of Hot Torsion Parameters on Development of Ultrafine Ferrite Grains in Microalloyed Steel

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Journal of Iron and Steel Research International 2012年第1期19卷 47-52页

作者： b Eghbali Department of Materials Engineering Sahand University of Technology

Hot torsion testing was performed on a low carbon Nb-Ti microalloyed steel to study the effects of hot tor- sion parameters, strain and strain rate, on ultrafine ferrite grains production through dynamic strain-induced trans- formation, at a deformation temperature just above At3. The initiation and evolution of ultrafine ferrite grains were studied. The results show that the amount of strain and strain rate has conversely effect on the volume fraction and grain size of ultrafine ferrite grains. With increasing strain, the interior of austenite grains become activated as nucle- ation sites for fine ferrite grains. As a result, ferrite grains continuously nucleate not only at the former austenite grain boundaries but also inside the austenite grains which leads to a rapid increase in volume fraction of ultrafine grains. Increasing of strain rate reduces the tendency of ferrite grains coarsening so that ultrafine ferrite grains are achieved, while the volume fraction of ultrafine grains decreases at the same strain level.

关键词： dynamic strain induced transformation grain refinement ferrite hot torsion steel