Stability of an oscillating tip in Non-Contact Atomic Force Microscopy: theoretical and numerical investigations

This paper is a theoretical and a numerical investigation of the stability of a tip-cantilever system used in Non-Contact Atomic Force Microscopy (NC-AFM) when it oscillates close to a surface. No additional dissipative force is considered. The theoretical approach is based on a variationnal method exploiting a coarse grained operation that gives the temporal dependence of the nonlinear coupled equations of motion in amplitude and phase of the oscillator. Stability criterions for the resonance peak are deduced and predict a stable behavior of the oscillator in the vicinity of the resonance. The numerical approach is based on results obtained with a virtual NC-AFM developped in our group. The effect of the size of the stable domain in phase is investigated. These results are in particularly good agreement with the theoretical predictions. Also they show the influence of the phase shifter in the feedback loop and the way it can affect the damping signal

Явище синонімії в мовленні представника східнослобожанської говірки (на матеріалі с. Шульгінка Старобільського району Луганської обл.)

У статті розглянуто явище синонімії у розмовному мовленні представника східнослобожанської говірки; проаналізовано синоніми, визначено їх основні типи: семантичні, контекстуальні, стилістичні (емоційні) та абсолютні. За результатами спостережень виявлено синонімічні ряди; класифіковано їх за повнозначними частинами мови, позиційним розташуванням у контексті, тематичною групою тощо. У діалектних текстах мовної особистості досліджено стилістичні функції синонімів, а також їхню емоційно-експресивну забарвленість.В статье рассмотрено явление синонимии в разговорной речи представителя восточнослобожанского говора; проанализированы синонимы, определены основные их типы: семантические, контекстуальные, стилистические (эмоциональные) и абсолютные. По результатам наблюдений обнаружены синонимические ряды; осуществлена классификация их относительно частей речи, позиционного расположения в контексте, тематической группы и т.д. В диалектных текстах языковой личности исследовано стилистические функции синонимов, а также их эмоционально-экспрессивную окраску.The phenomenon of synonymy in spoken language of spokesman of East Slobozhanshchina dialects is observed in the article; the synonyms are recorded and analysed; their main types (semantic, contextual, stylistic (emotional), absolute) are determined. The synonymic rows are shown as a result of observation; they were classified as part of speech of full meaning, as position disposition in the context, as thematic group etc. The stylistic functions of synonyms and also their emotional-expressive tint are investigated in dialectal texts of linguistic personality

Influence of noncontact dissipation in the tapping mode: Attempt to extract quantitative information on the surface properties with the local force probe method

In the Tapping mode, a variation of the oscillation amplitude and phase as a function of the tip sample distance is the necessary measurement to access quantitatively to the properties of the surface. In the present work, we give a systematic comparison between experimental data recorded on two surfaces, phase and amplitude, and theoretical curves. With an interaction between the tip and the surface taking into account an attractive and a repulsive term, the analytical approach is unable to properly describe the relationship between the phase variation and the oscillation amplitude variation. When an additional dissipation term is involved, due to the attractive interaction between the tip and the surface, the model gives a good agreement with the recorded data. Particularly, the trends in the phase variations related to the noncontact situations have been found to be amenable to an analysis based upon a simple viscoelastic behavior of the surface

Trophic relationships between palms and bruchids (Coleoptera: Bruchidae: Pachymerini) in Peruvian Amazonia

Qualitative and quantitative host plant data are provided for palm bruchids in a part of Amazonia from where previously few or no data were available. The host range and geographical distribution of several species are extended. The role of fruit structure on susceptibility to bruchid infestation and fruit maturity on oviposition site selection is discussed. The importance of mesologic conditions, particularly in areas subjected to flooding, on population dynamics of palm seed beetles is stressed. A specialist parasitoid of Caryoborus serripes, which is a specific predator of Astrocaryum nuts, is recorded for the first time; a trichogrammatid parasitic on the eggs of the same bruchid is also identified

Trophic relationships between palms and bruchids (Coleoptera: Bruchidae: Pachymerini) in Peruvian Amazonia

Qualitative and quantitative host plant data are provided for palm bruchids in a part of Amazonia from where previously few or no data were available. The host range and geographical distribution of several species are extended. The role of fruit structure on susceptibility to bruchid infestation and fruit maturity on oviposition site selection is discussed. The importance of mesologic conditions, particularly in areas subjected to flooding, on population dynamics of palm seed beetles is stressed. A specialist parasitoid of Caryoborus serripes, which is a specific predator of Astrocaryum nuts, is recorded for the first time; a trichogrammatid parasitic on the eggs of the same bruchid is also identified

Besouros nocivos à bacabeira: Dynamis borassi e Foveolus aterpes.

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Entomofauna fitófaga em palmeiras nativas da Amazônia.

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Insetos visitantes e polinizadores em palmeiras nativas da Amazônia.

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