24 research outputs found

    Структура и функции репликативного нейроподобного модуля

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    Описывается технология построения нейросетевой системы искусственного интеллекта на стыке декларативного программирования и машинного обучения на основе моделирования кортикальных колонок. Используя доступный материал и сравнительно простые явления, эволюционные механизмы создали сложноорганизованные разумные системы. Из этого следует вывод, что искусственный интеллект также должен основываться на простых, но масштабируемых и биоправдоподобных алгоритмах, в которых стохастическая динамика корковых нейронных модулей позволяет быстро и эффективно находить решения сложных проблем. Цель исследования – алгоритмическая формализация на уровне репликативных нейросетевых комплексов. Базовый модуль искусственного интеллекта представлен как специализация и формализация понятия «китайская комната», введенного Джоном Сёрлом. Приведены результаты экспериментов по прогнозированию бинарных последовательностей. Компьютерная симуляця показала высокую эффективность реализации предложенных алгоритмов, при этом вместо использования для каждой задачи тщательно подобранного и адаптированного отдельного метода с частично эквивалентной переформулировкой задач были применены стандартный единый подход и единые параметры алгоритма. Делается вывод, что результаты экспериментов показывают возможность эффективных прикладных решений на базе предложенной технологии. Представленная технология позволяет создать самообучающиеся и планирующие деятельность системы

    Picosecond-laser-induced structural modifications in the bulk of single-crystal diamond

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    Arrays of through laser-graphitized microstructureshavebeenfabricatedintypeIIasingle-crystal1.2-mmthick diamond plates by multipulse laser irradiation with 10-ps pulses at λ=532 nm wavelength. Raman and photoluminescence (PL) spectroscopy studies of the bulk microstructures have evidenced the diamond transformation to amorphous carbon and graphitic phases and the formation of radiation defects pronounced in the PL spectra as the self-interstitial related center, the 3H center, at 504 nm. It is found that the ultrafast-laser-induced structural modifications in the bulk of single-crystal diamond plates occur along{111}planes, known as the planes of the lowest cleavage energy and strength in diamond

    Nonspecific stress response to temperature increase in Gammarus lacustris Sars with respect to oxygen-limited thermal tolerance concept

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    The previously undescribed dynamics of the heat shock protein HSP70 and subsequent lipid peroxidation products have been assessed alongside lactate dehydrogenase activity for Gammarus lacustris Sars, an amphipod species from the saltwater Lake Shira (Republic of Khakassia). Individuals were exposed to a gradual temperature increase of 1 °C/hour (total exposure duration of 26 hours) starting from the mean annual temperature of their habitat (7 °C) up to 33 °C. A complex of biochemical reactions occurred when saltwater G. lactustris was exposed to the gradual changes in temperature. This was characterized by a decrease in lactate dehydrogenase activity and the launching of lipid peroxidation. The HSP70 level did not change significantly during the entire experiment. In agreement with the concept of oxygen-limited thermal tolerance, an accumulation of the most toxic lipid peroxides (triene conjugates and Schiff bases) in phospholipids occurred at the same time and temperature as the accumulation of lactate. The main criterion overriding the temperature threshold was, therefore, the transition to anaerobiosis, confirmed by the elevated lactate levels as observed in our previous associated study, and by the development of cellular stress, which was expressed by an accumulation of lipid peroxidation products. An earlier hypothesis, based on freshwater individuals of the same species, has been confirmed whereby the increased thermotolerance of G. lacustris from the saltwater lake was caused by differences in energy metabolism and energy supply of nonspecific cellular stress-response mechanisms. With the development of global climate change, these reactions could be advantageous for saltwater G. lacustris. The studied biochemical reactions can be used as biomarkers for the stress status of aquatic organisms when their habitat temperature changes

    Probing the Nanostructure of Neutron-Irradiated Diamond Using Raman Spectroscopy

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    Disordering of crystal lattice induced by irradiation with fast neutrons and other high-energy particles is used for the deep modification of electrical and optical properties of diamonds via significant nanoscale restructuring and defects engineering. Raman spectroscopy was employed to investigate the nature of radiation damage below the critical graphitization level created when chemical vapor deposition and natural diamonds are irradiated by fast neutrons with fluencies from 1 × 1018 to 3 × 1020 cm−2 and annealed at the 100–1700 °C range. The significant changes in the diamond Raman spectra versus the neutron-irradiated conditions are associated with the formation of intrinsic irradiation-induced defects that do not completely destroy the crystalline feature but decrease the phonon coherence length as the neutron dose increases. It was shown that the Raman spectrum of radiation-damaged diamonds is determined by the phonon confinement effect and that the boson peak is present in the Raman spectra up to annealing at 800–1000 °C. Three groups of defect-induced bands (first group = 260, 495, and 730 cm−1; second group = 230, 500, 530, 685, and 760 cm–1; and third group = 335, 1390, 1415, and 1740 cm−1) were observed in Raman spectra of fast-neutron-irradiated diamonds

    Raman Study of the Diamond to Graphite Transition Induced by the Single Femtosecond Laser Pulse on the (111) Face

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    The use of the ultrafast pulse is the current trend in laser processing many materials, including diamonds. Recently, the orientation of the irradiated crystal face was shown to play a crucial role in the diamond to graphite transition process. Here, we develop this approach and explore the nanostructure of the sp2 phase, and the structural perfection of the graphite produced. The single pulse of the third harmonic of a Ti:sapphire laser (100 fs, 266 nm) was used to study the process of producing highly oriented graphite (HOG) layers on the (111) surface of a diamond monocrystal. The laser fluence dependence on ablated crater depth was analyzed, and three different regimes of laser-induced diamond graphitization are discussed, namely: nonablative graphitization, customary ablative graphitization, and bulk graphitization. The structure of the graphitized material was investigated by confocal Raman spectroscopy. A clear correlation was found between laser ablation regimes and sp2 phase structure. The main types of structural defects that disrupt the HOG formation both at low and high laser fluencies were determined by Raman spectroscopy. The patterns revealed give optimal laser fluence for the production of perfect graphite spots on the diamond surface

    IR Spectroscopy of Vacancy Clusters (Amber Centers) in CVD Diamonds Nanostructured by Fast Neutron Irradiation

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    We investigated the IR absorption spectra of CVD diamond damaged by fast neutrons (>0.1 MeV) with high fluences ranging from 1 × 1018 to 2 × 1019 cm−2 and annealed at temperatures of 200 °C to 1680 °C. After annealing above 1000 °C, the formation of “amber-centers” (ACs), associated with multivacancy clusters, is detected as deduced from the appearance of a strong absorption line at 4100 cm−1. Moreover, the concentration of the ACs in the irradiated diamond can be an order of magnitude higher than that observed previously in the darkest brown natural diamonds. A number of other absorption lines, including the H1b center at 4936 cm−1 (0.612 eV) and new lines at ~5700 cm−1 (0.706 eV) and 9320 cm−1 (1.155 eV) not reported before in the literature, are observed, and their intensity evolutions at annealing temperatures are documented. At the highest fluences, all the lines show reduced intensities and broadening and spectral shifts due to a very high defect concentration and partial amorphization. The obtained experimental data can be used for the analysis of defect generation, transformations and healing in irradiated synthetic and natural diamonds

    Nano-carbon pixels array for ionizing particles monitoring

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    The paper deals on the response of a polycrystalline diamond sensor, 500 μm thick, to particles from a 90Sr β-source. 21×21 nano-carbon pads, with 0.18 mm×0.18 mm area each, were realized by ArF excimer laser irradiation on one diamond face, whereas a 7×7 mm2 backside contact was fabricated and used for sensor biasing during characterization of sensor under β-source irradiation. The carbon pads embrace a number of grains, which show different degrees of surface graphitization dependent on the grain orientations. Each carbon pad exhibits a linear I(V) response up to 200 V. The average number of charge carriers collected by a single pixel, as well as the distribution of pixels involved by the impinging particle tracking, is analyzed as a function of the applied voltage recording the signals acquired by 16 pixels at a time. The pulse height distribution is not affected by reversing the bias polarity. For a single pixel, the most probable collected charge value is 1.40±0.02 fC whereas the main value gives coll=1.67±0.02 fC (10430 ±120 electrons). The charge collection distance was measured tacking into account the effect induced by high- energy electrons and found to be 285±3 μm, demonstrating the absence of bulk defects induced by the laser graphitization processing. Cross-talk effects between nearest-neighbor pixels has been excluded analyzing the results obtained in a batch of more than 1000 events even if the same cannot be excluded under higher energy particles

    Technology Features of Diamond Coating Deposition on a Carbide Tool

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    The production of carbide tools with polycrystalline diamond coatings, which are used for processing modern carbon composite materials, includes a number of technological techniques that ensure reliable adhesion of the coating to the substrate. This review examines these features of substrate-surface pretreatment to improve adhesion, which includes chemical etching, mechanical hardening, modification by ion beams, plasma treatment and application of buffer layers between the substrate and the coating. This review also discusses the advantages and disadvantages of the most common methods for obtaining polycrystalline diamond coatings using hot filament and deposition of coatings from microwave plasma
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