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Changes in the Dynamics of a Rössler Oscillator by an External Forcing

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Chinese Physics Letters 2013年第3期30卷 22-25页

作者： Amanda C.Mathias paulo C.Rech Departamento de Física Universidade do Estado de Santa Catarina89219-710 JoinvilleBrazil

We report some results indicating changes in the observed dynamics of the Rössler model under the influence of external sinusoidal *** varying the control parameters of the external sinusoidal forcing,namely the amplitude and the angular frequency,we show,through numerical simulations which include parameter planes and Lyapunov exponents,that the external forcing can produce both chaos-order and order-chaos *** also show that the sinusoidal forcing may generate hyperchaos.

关键词： chaos sinusoidal transitions

A Parameter-Space Analysis of the Rikitake System

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Chinese Physics Letters 2013年第12期30卷 13-16页

作者： Rodrigo A.da Silva paulo C.Rech Departamento de Física Universidade do Estado de Santa Catarina89219-710 JoinvilleBrazil

We investigate analytically and numerically the dynamics of the Rikitake *** Routh–Hurwitz criterion is used to study the stability of the equilibrium points of the differential equation system model,as functions of two *** dynamics of the model are numerically studied using diagrams that associate colors to the largest Lyapunov exponent value,in two-dimensional parameter ***,phase-space plots and bifurcation diagrams are used to distinguish periodic and chaotic attractors.

关键词： bifurcation exponent chaotic

Nutrient content affecting Spodoptera frugiperda and Dalbulus maidis occurrence in corn

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Insect Science 2007年第2期14卷 117-123页

作者： CRISTINA SCHETINO BASTOS JOAO CARLOS CARDOSO GALVAO MARCELO COUTINHO PICANCO paulo ROBERTO GOMES PEREIRA paulo ROBERTO CECON EMBRAPA/Algodao Centenário Campina Grande PB Brazil Departamento de Fitotecnia Universidade Federal de Vicosa (UFV) Vicosa MG Brazil. Departamento de Biologia Animal Universidade Federal de Vicosa (UFV) Vicosa MG Brazil. Departamento de Informática Campus Universitário Universidade Federal de Vicosa (UFV) Vicosa MG Brazil.

This work aims to study the effect of the nutrient contents in the leaves of corn on the incidence of Spodopterafrugiperda （Smith）（Lepidoptera： Noctuidae） and Dalbulus maidis （Delong ＆ Wolcott）（Homoptera： Cicadellidae）. The treatments were represented by unfertilized corn plants and corn plants fertilized with 250 kg of the formulation 4-14-8 （N- P-K）＋ 100 kg of ammonium sulfate （AS）/ha and 500 kg of the formulation 4-14-8 （N-P-K）＋200 kg of AS/ha, arranged in randomized blocks with four replicates. Attacks by S. frugiperda and D. maidis were higher as the nitrogen, sulfur, calcium and copper content in the leaves of corn increased. The effects of calcium and copper found in this study were not consistent with that of lower susceptibility associated with higher levels of these nutrients mentioned in the literature. We believe that there was a cumulative effect of the nutrients altogether, building up a nutritiously better vegetable which in turn had less reserve for defense, or that the content of both nutrients in the leaves were not high enough to induce such effects.

关键词： calcium copper corn cicada fall armyworm fertilization nitrogen sulfur

Laparoscopic resection for hepatocellular carcinoma: eastern and western experiences

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Chinese Journal of Cancer Research 2014年第3期26卷 234-236页

作者： paulo Herman Fabricio Ferreira Coelho Liver Surgery Unit Department of GastroenterologyUniversity of Sao Paulo Medical School

Hepatocellular carcinoma （HCC） is the most common primary liver cancer （1）. The incidence is rising in the last decades due to many factors, especially hepatitis C, alcoholic liver disease and non-alcoholic steatohepatitis. Moreover, the introduction of screening programs in patients with chronic liver disease has led to an increase in HCC diagnosis （1,2）. In the western world, 80% to 90% of HCC eases occur in patients with liver cirrhosis （3） while this proportion is lower in some regions in Asia and sub-Saharian Africa, where hepatitis B remains as an important etiologic factor for chronic liver disease （2,4）. In 1990, the annual world frequency of HCC was 437,000 cases/year （1）, and in 2012 the number reached 782,200 cases/year being responsible for 746,000 deaths （5）. Nowadays, HCC represents the 6th most frequent neoplastic disease in the world and the 3rd in mortality （5）.

关键词： HCC eastern and western experiences Laparoscopic resection for hepatocellular carcinoma

Addressing the CQI feedback delay in 5G/6G networks via machine learning and evolutionary computing

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Intelligent and Converged Networks 2022年第3期3卷 271-281页

作者： Andson Balieiro Kelvin Dias paulo Guarda Centro de Informática(CIn) Universidade Federal de PernambucoRecife 50740-560Brasil Motorola Mobility Mogi Mirim 13800-206Brazil

5G networks apply adaptive modulation and coding according to the channel condition reported by the user in order to keep the mobile communication ***,the delay incurred by the feedback may make the channel quality indicator(CQI)*** paper addresses this issue by proposing two approaches,one based on machine learning and another on evolutionary computing,which considers the user context and signal-to-interference-plus-noise ratio(SINR)besides the delay length to estimate the updated SINR to be mapped into a CQI *** proposals are designed to run at the user equipment(UE)side,neither requiring any change in the signalling between the base station(gNB)and UE nor overloading the *** are evaluated in terms of mean squared error by adopting 5G network simulation data and the results show their high accuracy and feasibility to be employed in 5G/6G systems.

关键词： channel quality indicator(CQI)feedback delay 5G/6G networks machine learning evolutionary computing

A Study of Fluid Flow in Sediments and the Effect of Tidal Pumping

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Journal of Earth Science 2017年第5期28卷 842-847页

作者： paulo Waltrich John Whitehead Richard Hughes Karsten Thompson Department of Petroleum Engineering Louisiana State University

Offshore drilling and production operations can result in spills or leaks of hydrocarbons into seabed sediments, which can potentially contaminate these sediments with oil. If this oil later mi- grates to the water surface it has the potential for negative environmental impacts. For proper contin- gency planning and to avoid larger consequences in the environment, it is essential to understand me- chanisms and rates for hydrocarbon migration from oil containing sediments to the water surface as well as how much will remain trapped in the sediments. It is believed that the amount of oil transported out of the sediment can be affected by tidal pumping, a common form of subterranean groundwater dis- charge （SGD）. However, we could find no study experimentally investigating the phenomenon of fluid flow in subsea sediments containing oil and the effects of tidal pumping. This study presents an experi- mental investigation of tidal pumping to determine if it is a possible mechanism that may contribute to the appearance of an oil sheen on the ocean surface above a sediment bed containing oil. An experimen- tal apparatus was constructed of clear PVC pipe allowing for oil migration to be monitored as it flowed out of a sand pack containing oil, while tidal pressure oscillations were applied in three different man- ners. The effect of tidal pumping was simulated via compression of air above the water （which simulated the increasing static head from tidal exchange）. Experimental results show that sustained oil release oc- curred from all tests, and tests with oscillating pressure produced for longer periods of time. Further- more, the experimental results showed that the oil migration rate was affected by grain size, oil satura- tion, and oscillation wave type. In all oscillating experiments the rate and ultimate recovery was less than the comparable static experiments. For the conditions studied, the experimental results indicate that with an oscillating pressure on top of a

关键词： tidal pumping oil migration sediments oil release rate.

Rainfall erosivity and erosivity density through rainfall synthetic series for Sao paulo State,Brazil:Assessment,regionalization and modeling

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International Soil and Water Conservation Research 2022年第3期10卷 355-370页

作者： David Bruno de Sousa Teixeira Roberto Avelino Cecílio Joao paulo Bestete de Oliveira Laura Thebit de Almeida Gabrielle Ferreira Pires Department of Agricultural Engineering Federal University of ViçosaViçosaMG36570-900Brazil Department of Forest and Wood Sciences Federal University of Espírito SantoJer^onimo MonteiroES29550-000Brazil Federal Institute of Espírito Santo Campus AlegreAlegreES29520-000Brazil

Rainfall is the main cause of erosion of Brazilian soils,which makes assessing the rainfall erosivity factor(RE)and the erosivity density(ED)fundamental for soil and water ***,the objectives of this study were:i)to estimate the RE and ED for Sao paulo State,Brazil,using synthetic series of pluviographic data;ii)to define homogeneous regions regarding rainfall erosivity;and iii)to generate regression models for rainfall erosivity estimates in each of the homogeneous *** series of pluviographic data were initially obtained on a sub-daily scale from the daily rainfall records of 696 rainfall *** RE values were then estimated from the synthetic rainfall data,and ED was calculated from the relationship between erosivity and rainfall *** and annual maps for RE and ED were *** clustering analysis was used to define homogeneous regions in terms of rainfall erosivity,and regionalized regression models for estimating RE were *** results demonstrate high spatial variability of RE in Sao paulo,where the highest annual values were observed in the coastal *** to March concentrate approximately 60%of the intra-annual *** highest values of annual ED were observed in regions with intense agricultural *** definition of five homogeneous regions concerning the rainfall erosive potential evidenced distinct seasonal patterns of the spatial distribution of ***,the high predictive accuracy of the regionalized models obtained characterizes them as essential tools for reliable estimates of rainfall erosivity,and contribute to better soil conservation planning.

关键词： Soil erosion Stochastic weather generator Homogeneous regions Modified Fournier index Regression models

Proportionally Modular Diophantine Inequalities and Their Multiplicity

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Acta Mathematica Sinica,English Series 2010年第11期26卷 2059-2070页

作者： José Carlos ROSALES Manuel Batista BRANCO paulo VASCO Departamento de lgebra Universidad de Granada Departamento de Matemática Departamento de Matemática Universidade de Trás-os-Montes e Alto Douro

Let I be an interval of positive rational numbers. Then the set S （I） = T ∩ N, where T is the submonoid of （Q0＋, ＋） generated by T, is a numerical semigroup. These numerical semigroups are called proportionally modular and can be characterized as the set of integer solutions of a Diophantine inequality of the form ax rood b 〈 cx. In this paper we are interested in the study of the maximal intervals I subject to the condition that S （I） has a given multiplicity. We also characterize the numerical semigroups associated with these maximal intervals.

关键词： Numerical semigroup Diophantine inequality multiplicity Frobenius number

Analysis of Surface Integrity in Drilling Metal Matrix and Hybrid Metal Matrix Composites

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Journal of Materials Science & Technology 2012年第8期28卷 761-768页

作者： T.Rajmohan K.Palanikumar J.paulo Davim Department of Mechanical Engineering Sri Chandrasekharendra Saraswathi Viswa Maha Vidyalaya University Department of Mechanical Engineering Sri Sai Ram Institute of Technology Department of Mechanical Engineering University of AveiroCampus Santiago3810-193 AveiroPortugal

Hybrid metal matrix composites consist of at least three constituents-a metal or an alloy matrix and two reinforcements in various forms, bonded together at the atomic level in the composite. Despite their higher specific properties of strength and stiffness, the non homogeneous and anisotropic nature combined with the abrasive reinforcements render their machining difficult. In this paper, the surface integrity of machining in drilling hybrid composites has been discussed. Drilling tests are carried out at different spindle speed, feed rates, and different drill tool materials to investigate the effect of the various cutting parameters on the surface quality and the extent of the deformation of drilled surface due to drilling. Materials used for the present investigation are A1356/IOSIC （wt%） metal matrix and A1356/10SiC-3mica （wt%） hybrid composites. The composites are fabricated using stir casting route. The drilling tests are conducted on vertical computer numeric control （CNC） machining center using carbide, coated carbide and polycrystalline diamond （PCD） drills. The surface roughness decreases with increasing spindle speed and increases with increasing feed rate. The machined surface is analyzed by scanning electron microscopy （SEM）. SEM images of the machined surfaces indicate the presence of grooves and pits. Microhardness depth profiles indicate that the subsurface damage is limited to the top of 100-250 μm.

关键词： Hybrid composites Scanning electron microscopy (SEM) Subsurface Drilling