781 research outputs found
Electronic, magnetic and transport properties of Fe intercalated 2H-TaS studied by means of the KKR-CPA method
The electronic, magnetic and transport properties of Fe intercalated
2H-TaS have been investigated by means of the Korringa-Kohn-Rostoker (KKR)
method. The non-stoichiometry and disorder in the system has been accounted for
using the Coherent Potential Approximation (CPA) alloy theory. A pronounced
influence of disorder on the spin magnetic moment has been found for the
ferro-magnetically ordered material. The same applies for the spin-orbit
induced orbital magnetic moment and magneto-crystalline anisotropy energy. The
temperature-dependence of the resistivity of disordered 2H-FeTaS
investigated on the basis of the Kubo-St\v{r}eda formalism in combination with
the alloy analogy model has been found in very satisfying agreement with
experimental data. This also holds for the temperature dependent anomalous Hall
resistivity . The role of thermally induced lattice
vibrations and spin fluctuations for the transport properties is discussed in
detail
Mechanochemical Synthesis and Magnetic Characterization of Nanosized Cubic Spinel FeCr₂S₄ Particles
Nanosized samples of the cubic thiospinel FeCr2S4 were synthesized by ball milling of FeS and Cr2S3 precursors followed by a distinct temperature treatment between 500 and 800 °C. Depending on the applied temperature, volume weighted mean (Lvol) particle sizes of 56 nm (500 °C), 86 nm (600 °C), and 123 nm (800 °C) were obtained. All samples show a transition into the ferrimagnetic state at a Curie temperature TC of ∼ 167 K only slightly depending on the annealing temperature. Above TC, ferromagnetic spin clusters survive and Curie–Weiss behavior is observed only at T ≫ TC, with T depending on the heat treatments and the external magnetic field applied. Zero-field-cooled and field-cooled magnetic susceptibilities diverge significantly below TC in contrast to what is observed for conventionally solid-state-prepared polycrystalline samples. In the low-temperature region, all samples show a transition into the orbital ordered state at about 9 K, which is more pronounced for the samples heated to higher temperatures. This observation is a clear indication that the cation disorder is very low because a pronounced disorder would suppress this magnetic transition. The unusual magnetic properties of the samples at low temperatures and different external magnetic fields can be clearly related to different factors like structural microstrain and magnetocrystalline anisotropy
The host of the Type I SLSN 2017egm: A young, sub-solar metallicity environment in a massive spiral galaxy
Here we present an integral-field study of the massive, high-metallicity
spiral NGC 3191, the host of SN 2017egm, the closest SLSN Type I to date. We
use data from PMAS/CAHA and the public MaNGA survey to shed light on the
properties of the SLSN site and the origin of star-formation in this
non-starburst spiral galaxy. We map the physical properties different
\ion{H}{II} regions throughout the galaxy and characterize their stellar
populations using the STARLIGHT fitting code. Kinematical information allows to
study a possible interaction with its neighbouring galaxy as the origin of
recent star formation activity which could have caused the SLSN. NGC 3191 shows
intense star-formation in the western part with three large SF regions of low
metallicity. The central regions of the host have a higher metallicity, lower
specific star-formation rate and lower ionization. Modeling the stellar
populations gives a different picture: The SLSN region has two dominant stellar
populations with different ages, the youngest one with an age of 2-10 Myr and
lower metallicity, likely the population from which the SN progenitor
originated. Emission line kinematics of NGC 3191 show indications of
interaction with its neighbour MCG+08-19-017 at 45 kpc, which might be
responsible for the recent starburst. In fact, this galaxy pair has in total
hosted 4 SNe, 1988B (Type Ia), SN 2003ds (Type Ic in MCG+08-19-017), PTF10bgl
(SLSN-Type II) and 2017egm, underlying the enhanced SF in both galaxies due to
interaction. Our study shows that one has to be careful interpreting global
host and even gas properties without looking at the stellar population history
of the region. SLSNe seem to still be consistent with massive stars ( 20
M) requiring low () metallicity and those environments
can also occur in massive, late-type galaxies but not necessarily starbursts.Comment: Accepted for publication in A&A, 13 pages, 11 figures, 7 tables.
Abstract has been reduced to match arXiv form requirement
The provision of solar energy to rural households through a fee-for-service system
This baseline report is part of an evaluation commissioned by the Policy
and Operations Evaluation Department (IOB) of the Netherlands
Ministry of Foreign Affairs. It belongs to a series of impact evaluations
of renewable energy and development programmes supported by the
Netherlands, with a focus on the medium and long term effects of these
programmes on end-users or final beneficiaries. A characteristic of
these studies is the use of mixed methods, being quantitative research
techniques, in combination with qualitative techniques, to get insight in
the magnitude of effects. The purpose of the impact evaluations is to
account for assistance provided and to draw lessons from the findings
for improvement of policy and policy implementation. The results of
these impact evaluations will be input to a policy evaluation of the
“Promoting Renewable Energy Programme” (PREP) to be concluded in
2014
Ветро-дизельная система электроснабжения поселка
Работа направлена на решение проблемы электроснабжения отдаленных районов.
Объектом исследования является гибридная ветро-дизельная система электроснабжения, находящаяся на юге Кемеровской области на высоте 1260 метров. В процессе исследования проводились анализ материалов в открытом доступе, запросы производителям, технико-экономическое сравнение.
В результате исследования определен наиболее выгодный вариант.
Область применения: энергодефицитные отдаленные районы, наиболее перспективные с точки зрения малой энергетики и обладающие потенциалом ВИЭ, в частности ветропотенциалом.
Экономическая эффективность проекта заключается в снижении стоимости электроэнергии в шесть раз.Die Arbeit zielt auf die Losung der Energieversorgung von entlegenen Gebieten.
Gegenstand der Studie ist ein Hybrid wind-Diesel-System der Elektrizitatsversorgung, das sich im Suden vom Gebiet Kemerowo auf einer Hohe von 1260 Meter. In der Studie wurden fur die Analyse von Materialien in der offentlichkeit, Anfragen von Herstellern, die technisch-wirtschaftlichen Vergleich.
Die Studie ermittelt die Gunstigste Variante.
Einsatzbereich: energiedefizite Randgebiete, die vielversprechendsten in Bezug auf niedrige Energie und mit dem Potential der erneuerbaren Energien, insbesondere Energiepotenzial.
Die Wirtschaftseffektivitat des Projektes besteht in der Reduzierung der Kosten der Stromerzeugung in sechs mal
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