494 research outputs found
The Fermi Surface Effect on Magnetic Interlayer Coupling
The oscillating magnetic interlayer coupling of Fe over spacer layers
consisting of CuPd 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
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
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
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
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
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
Определение облика космического аппарата, предназначенного для посадки на космическое тело с малым гравитационным полем
Cost-effectiveness of CTA, MRA and DSA in patients with non-traumatic subarachnoid haemorrhage
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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