864 research outputs found
Justification of binder material selection for carbon particles incorporation into fibrous electromagnetic radiation absorber
The paper presents justification of a binder material for incorporating carbon particles into the interfiber space of electromagnetic radiation absorber. A method for carbon particles incorporation into a fibrous material has been developed. It is based on applying a carbon-containing nanocomposite to the fibrous material’s surface. Previously, the research of carbon particles incorporation into a synthetic material by using an aqueous solution were carried out, which ensured a uniform distribution of carbon particles in the material structure. However, the properties of the material have changed significantly upon mechanical deformation. Therefore, the carbon particles incorporation process was investigated using various nanocomposites obtained on the basis of mixtures of vinyl acetate polymer, or epoxy polymer, or surface-active substance with carbon black. Based on the results of electron microscopic analysis and the reflection and transmission coefficients frequency dependences in the frequency range 0.7–17 GHz, the efficiency of using a nanocomposite based on a mixture of surface-active substance and carbon black to create electromagnetic radiation absorbers was justified. Such electromagnetic radiation absorbers have the transmission coefficient value about –18 dB and reflection coefficient value about –12 dB in the frequency range 7–13 GHz. Carbon-containing electromagnetic radiation absorbers based on fibrous material have thickness less than 3 mm, properties of flexibility and resistance to mechanical deformation. It can be used in various fields, in particular for hiding objects from radio frequency reconnaissance or protecting equipment from external interference.The paper presents justification of a binder material for incorporating carbon particles into the interfiber space of electromagnetic radiation absorber. A method for carbon particles incorporation into a fibrous material has been developed. It is based on applying a carbon-containing nanocomposite to the fibrous material’s surface. Previously, the research of carbon particles incorporation into a synthetic material by using an aqueous solution were carried out, which ensured a uniform distribution of carbon particles in the material structure. However, the properties of the material have changed significantly upon mechanical deformation. Therefore, the carbon particles incorporation process was investigated using various nanocomposites obtained on the basis of mixtures of vinyl acetate polymer, or epoxy polymer, or surface-active substance with carbon black. Based on the results of electron microscopic analysis and the reflection and transmission coefficients frequency dependences in the frequency range 0.7–17 GHz, the efficiency of using a nanocomposite based on a mixture of surface-active substance and carbon black to create electromagnetic radiation absorbers was justified. Such electromagnetic radiation absorbers have the transmission coefficient value about –18 dB and reflection coefficient value about –12 dB in the frequency range 7–13 GHz. Carbon-containing electromagnetic radiation absorbers based on fibrous material have thickness less than 3 mm, properties of flexibility and resistance to mechanical deformation. It can be used in various fields, in particular for hiding objects from radio frequency reconnaissance or protecting equipment from external interference
Trace element homogeneity from micron- to atomic scale: Implication for the suitability of the zircon GJ-1 as a trace element reference material
The quality of a chemical reference material relies on the fact that the composition of the material is homogeneous across all scales. A series of different techniques have been used to evaluate the trace element homogeneity of the GJ-1 reference zircon from the micron- to atomic scale. Cathodoluminescence imaging was conducted along with quantitative crystallographic orientation analysis and trace element analysis using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). The nanometre-scale homogeneity was evaluated by analysing five mineral tips using atom probe tomography, which provides atomic scale three dimensional chemical reconstructions with unprecedented spatial resolution. Results show that the GJ-1 reference zircon is homogeneous at all scales, both structurally and chemically. Crystallographic orientation data confirms that this gem quality zircon has no detectable internal crystallographic orientation changes such as crystal-plastic deformation features or cracks. No mineral inclusions were found. Atom probe tomography shows that there is a lack of any chemical clustering or other modes of spatially defined elemental accumulation or depletion for the most abundant trace elements such as Y, Yb and Hf. This finding is supported by LA-ICPMS data revealing homogeneity within the analytical precision. Trace elements of significant abundance include P, Yb, Y, U and Hf, with contents of 30 ± 6, 65 ± 2, 238 ± 5, 284 ± 14 and 6681 ± 57 ppm, respectively. Hence, the GJ-1 zircon used as a reference zircon for UPb and Hf-isotopic studies is also a suitable zircon reference material for trace element analyses
Оriginal arab culture in Israel
The article discusses the controversial situation in which Arab culture exists and develops in modern Israel. In particular, special attention is paid to the fact that the Arab population in Israeli society has its own distinctive cultural characteristics, national identity, which differs from that of Israel
The geochronological framework of the Irumide Belt: A prolonged crustal history along the margin of the Bangweulu Craton.
Ion microprobe U-Th-Pb analyses of zircon from 40 granitoid rocks collected from the late Mesoproterozoic Irumide Belt in Central Southern Africa, along the southern margin of the Archean to Paleoproterozoic Bangweulu Block, provide a comprehensive set of age data for this complex orogen. The data indicate that the Irumide Belt is constructed on a basement of principally Paleoproterozoic (ca. 2.05–1.93 Ga) age with a subordinate Neoarchean (ca. 2.73 Ga) component, which is overlain by a platformal quartzite-pelite succession known as the Muva Supergroup. Previously published U-Pb detrital zircon data for the Paleoproterozoic Muva Supergroup, which show age populations that match all of the pre-1.9 Ga basement components identified within the Irumide Belt, suggest that the pre-Muva basement was assembled as a coherent block by ~1.8 Ga, which we refer to as the Bangweulu Craton. The southern margin of the Bangweulu Craton was then intruded by a previously unrecognized suite of biotite-bearing granitoid rocks between 1.66 and 1.55 Ga, not recorded elsewhere in the region, and was later the site of emplacement of voluminous granitoid magmatism during the Irumide Orogeny at between 1.05 and 1.00 Ga. Hf isotopic data from zircon in these suites indicate variable influence from cryptic Archean rocks in the lower crustal melting zone of the Bangweulu Block. U-Pb analyses of inherited zircon cores in magmatic zircon in these granitoid rocks, directly confirm the presence of this reworked cryptic Archean basement of the Bangweulu Craton.The age data confirm previously proposed tectonic models for the Mesoproterozoic evolution of central Africa, refuting the presence of a continent-spanning Grenvillian-aged Orogen, including the Kibaran Belt, Irumide Belt and Choma-Kalomo Block of central Africa and connecting with Mesoproterozoic terranes further south along the margins of the Kalahari Craton. The data clearly show that the Proterozoic tectonic evolution of the Bangweulu Craton, which became attached to the southern margin of the larger Congo Craton during the Mesoproterozoic, involved a series of distinct convergent orogenic episodes affecting and reworking its southern (passive) margin. The mismatch in timing of Mesoproterozoic orogenic activity along the Bangweulu Craton, compared to that on the margins of the Kalahari, is compatible with the notion that these continental fragments were not juxtaposed along these Mesoproterozoic belts and in their present-day relative positions at the time. Whether either of these central and southern African cratons did form part of Rodinia, however, remains a matter for debate
The healing magic rituals in old russian culture
The article examines the rituals of healing magic and presentation of the disease in ancient culture. It is shown that the therapeutic magic was the cultural form in which traditional medicine was born and poetry.В статье исследуются ритуалы лечебной магии и представления о болезни в древнерусской культуре. Показывается, что лечебная магия была той культурной формой, в рамках которой рождались народная медицина и поэзия
The conformity as the principle of improving the quality of education
The article explores the application of the principle of culture cultivations in cultural studies. On the example of quiz questions on the history of culture, the possibility of increasing student interest and amateur performance is shown.В статье исследуется применение принципа культуросообразности на занятиях по культурологии. На примере вопросов игр-викторин по истории культуры показывается возможность повышения заинтересованности и самодеятельности студентов
The images of «special» children in the history of culture
The article investigates the transformation of the image of a child with physical and mental disabilities in the history of society, as well as its reflection in the literature. The phenomenon of «special» childhood is considered in two ways: in the historical and cultural context and on the example of literature for children with disabilities.В статье исследуется трансформация образа ребенка с физическими и психическими отклонениями в истории общества, а также его отражение в литературе. Феномен «особого» детства рассматривается двояко: в историко-культурном контексте и на примере литературы для детей-инвалидов
THE ORIGINS OF THE RISK INVESTMENT PROJECTS REAL IMPACTED BY INFLATION
In the article analyses the origins of inflation in Russian modern terms, moreover it focuses on impact of inflation process on risk appearance by realization of investment projects in the real sections of economy
THE ORIGINS OF THE RISK INVESTMENT PROJECTS REAL IMPACTED BY INFLATION
In the article analyses the origins of inflation in Russian modern terms, moreover it focuses on impact of inflation process on risk appearance by realization of investment projects in the real sections of economy
Active learning techniques in teaching bioethics
The article presents the use of active learning techniques in teaching bioethics of the medical University students. The example of the interactive approach to the bioethical challenges demonstrates better understanding of moral and axiological aspects of modern medicine.В статье исследуется использование методов активного обучения в процессе изучения биоэтики студентами медицинского университета. На примере интерактивного подхода к проблемам биоэтики показана возможность лучшего понимания нравственно-аксиологических аспектов современной медицины
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