490 research outputs found

    The Fermi Surface Effect on Magnetic Interlayer Coupling

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    The oscillating magnetic interlayer coupling of Fe over spacer layers consisting of Cux_{x}Pd1x_{1-x} alloys is investigated by first principles density functional theory. The amplitude, period and phase of the coupling, as well as the disorder-induced decay, are analyzed in detail and the consistency to the Ruderman-Kittel-Kasuya-Yoshida (RKKY) theory is discussed. For the first time an effect of the Fermi surface nesting strength on the amplitude is established from first principles calculations. An unexpected variation of the phase and disorder-induced decay is obtained and the results are discussed in terms of asymptotics

    Ballistic Spin Injection from Fe into ZnSe and GaAs with a (001), (111), and (110) orientation

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    We present first-principles calculations of ballistic spin injection in Fe/GaAs and Fe/ZnSe junctions with orientation (001), (111), and (110). We find that the symmetry mismatch of the Fe minority-spin states with the semiconductor conduction states can lead to extremely high spin polarization of the current through the (001) interface for hot and thermal injection processes. Such a symmetry mismatch does not exist for the (111) and (110) interfaces, where smaller spin injection efficiencies are found. The presence of interface states is found to lower the current spin polarization, both with and without a Schottky barrier. Finally, a higher bias can also affect the spin injection efficiency.Comment: 12 pages, 18 figure

    Организация пожарной безопасности мест хранения техники в ремонтных подразделениях вооруженных сил Российской Федерации

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    Проблему организацию противопожарной защиты мест обслуживания и ремонта ВВТ в войсковых частях необходимо решать комплексно, обращая внимание на реализацию противопожарных требований согласно строительных норм и правил пожарной безопасности, а также на организацию тушения пожара в случае его возникновения.The problem of organization of fire protection of the military service and maintenance sites in military units must be addressed in a comprehensive manner, paying attention to the implementation of fire safety requirements in accordance with building codes and fire safety rules, and also on the organization of fire extinguishing in the event of its occurrence

    Flow Matching for Scalable Simulation-Based Inference

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    Neural posterior estimation methods based on discrete normalizing flows have become established tools for simulation-based inference (SBI), but scaling them to high-dimensional problems can be challenging. Building on recent advances in generative modeling, we here present flow matching posterior estimation (FMPE), a technique for SBI using continuous normalizing flows. Like diffusion models, and in contrast to discrete flows, flow matching allows for unconstrained architectures, providing enhanced flexibility for complex data modalities. Flow matching, therefore, enables exact density evaluation, fast training, and seamless scalability to large architectures--making it ideal for SBI. We show that FMPE achieves competitive performance on an established SBI benchmark, and then demonstrate its improved scalability on a challenging scientific problem: for gravitational-wave inference, FMPE outperforms methods based on comparable discrete flows, reducing training time by 30% with substantially improved accuracy. Our work underscores the potential of FMPE to enhance performance in challenging inference scenarios, thereby paving the way for more advanced applications to scientific problems

    ЗАЩИТА ИНФОРМАЦИИ ОТ УГРОЗ СО СТОРОНЫ ОБСЛУЖИВАЮЩЕГО ПЕРСОНАЛА

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    В статье анализируются особенности решения проблемы защиты информации от так называемых легальных пользователей, обслуживающего персонала, крупномасштабных катастрофоустойчивых центров обработки данных. На основе обобщения ранее полученных результатов по конкретной реализации и проведенных дополнительных исследований формируются общие принципы построения и требовании к системотехнической и организационной составляющим системы защиты

    Experimental researches of mechanoelectrical transformations in tashtagolsky iron-ore field rock

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    Physical modeling in lab is approach of definition of main mechanical transformations behaviours inrock massive for choice of electromagnetical signals optimum characteristics and parameters ofelectomagnetical emission for developed approach of crush burst estimate. It is support connection betweenmechanoelectrical transformations characteristics and stress strain state of researched object. Physical modelingof mechanoelectrical transformations in the lab was made under a press by axial quasistatic compression of rockspecimen up to destruction. During stressing applied injections of specimens using determined acoustic signals. For researches used model and real specimens of Tashtagolsky iron-ore field rock, such as ore and matrix rock

    Cost-effectiveness of CTA, MRA and DSA in patients with non-traumatic subarachnoid haemorrhage

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    OBJECTIVES: Intra-arterial digital subtraction angiography (DSA), magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) are imaging modalities used for diagnostic work-up of non-traumatic subarachnoid haemorrhage. The aim of our study was to compare the cost-effectiveness of MRA, DSA and CTA in the first year after the bleed. METHODS: A decision model was used to calculate costs and benefits (in quality-adjusted life-years [QALYs]) that accrued to cohorts of 1,000 patients. Costs and characteristics of diagnostic tests, therapy, patients’ quality of life and associated costs were respected. The diagnostic strategy with highest QALYs and lowest costs was considered most cost-effective. RESULTS: DSA was the most effective diagnostic option, yielding on average 0.6039 QALYs (95 % CI, 0.5761–0.6327) per patient, followed by CTA 0.5983 QALYs (95 % CI, 0.5704–0.6278) and MRA 0.5947 QALYs (95 % CI, 0.5674–0.6237). Cost was lowest for DSA (39,808 €; 95 % CI, 37,182–42,663), followed by CTA (40,748 €; 95 % CI, 37,937–43,831) and MRA (41,814 €; 95 % CI, 38,730–45,146). A strategy of CTA followed by DSA if CTA was negative or coiling deemed not feasible, was as effective as DSA alone at average costs of 39,767€ (95 % CI, 36,903–42,402). CONCLUSION: A combined strategy of CTA and DSA was found to be the most cost-effective diagnostic approach. MAIN MESSAGES: • We defined a standard model for cost-effectiveness analysis in diagnostic imaging. • Comparing total 1-year health costs and benefits, CTA is superior to MRA. • A strategy of combining CTA and DSA was found to be the most cost-effective diagnostic approach
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