Autor: Wunderlich, J. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Uniaxial Strain Controlling Magnetic Anisotropy in (Ga,Mn)As
Autorzy:: Zemen, J.
Jungwirth, T.
Wunderlich, J.
Gallagher, B. L.
Tematy:: 75.30.Gw
78.55.Cr
75.50.Pp; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2047718.pdf Link otwiera się w nowym oknie
Opis:: A theoretical study of magnetocrystalline anisotropy controlled by in-plane lattice symmetry distortions is presented. The uniaxial strain, only presumed by earlier studies in order to model the observed uniaxial magnetic anisotropy, has recently become an experimentally accessible parameter. We show that the lithographically induced strain can compete with intrinsic symmetry breaking, easy axes can take general in-plane directions, and anisotropy fields scale linearly with strain for typical experimental strain magnitudes. Our results are in qualitative agreement with experimental results.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 2.

Tytuł:: Identifying the oldest larva of a myrmeleontiformian lacewing-a morphometric approach
Autorzy:: Herrera-Florez, A.F.
Braig, F.
Haug, C.
Neumann, C.
Wunderlich, J.
Hornig, M.K.
Haug, J.T.
Tematy:: Insecta
Myrmeleontidae
Ascalaphidae
compression fossil
fossil larva
Cretaceous
Crato Formation
Brazil; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/2082151.pdf Link otwiera się w nowym oknie
Opis:: Neuroptera is one of the smaller ingroups of Holometabola, the ingroup of Insecta characterised by “complete” metamorphosis. Neuroptera comprises about 6000 species in the modern fauna, but appears to have been more diverse in the past. While adults distantly resemble certain moths or damselflies, the larval forms of Neuroptera are mostly fierce predators with prominent venom-injecting stylets. The most well-known of these larvae are probably those of antlions. Antlions and their closer relatives (silky lacewings, split-footed lacewings, ribbon-winged lacewings, spoon-winged lacewings, and owlflies) form a distinct monophyletic ingroup of Neuroptera, Myrmeleontiformia, hence the antlion-like forms. The fossil record of antlion-like larvae dates back far into the Cretaceous; many forms are known by exceptionally wellpreserved specimens entrapped in amber. The oldest fossil record of a neuropteran larva (not an antlion-like form) comes from Lebanese amber. Interestingly, the supposedly oldest record of an antlion-like larva is preserved in rock and comes from the famous Lower Cretaceous Crato Formation. We re-evaluate this fossil based on high-resolution composite photography. Due to the non-availability of many key characters, standard procedures for identifying the specimen to a more narrow ingroup remains challenging. Therefore, we used a morphometric approach. A combination of non-metric multidimensional scaling (NMDS), parallel coordinate plots and discriminant function analysis indicates that the fossil is a representative of the group Ascalaphidae (owlflies) + Myrmeleontidae (antlions). We discuss implications of this result for the fossil record of neuropteran larvae. These include the rather derived morphology of the oldest fossil larva of Myrmeleontiformia in contrast to previous expectations. Furthermore, fossils from soil dwellers can not only be expected to be found in amber, but also as compression fossils.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: The Impact of Noise and Mismatch on SAR ADCs and a Calibratable Capacitance Array Based Approach for High Resolutions
Autorzy:: Mueller, J. H.
Strache, S.
Busch, L.
Wunderlich, R.
Heinen, S.
Tematy:: analog-digital conversion
analog-digital integrated circuits
calibration
CMOS integrated circuits
mathematical model
MATLAB
mixed analog digital integrated circuits
noise
numerical simulation
prediction methods; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/226396.pdf Link otwiera się w nowym oknie
Opis:: This paper describes widely used capacitor structures for charge-redistribution (CR) successive approximation register (SAR) based analog-to-digital converters (ADCs) and analyzes their linearity limitations due to kT/C noise, mismatch and parasitics. Results of mathematical considerations and statistical simulations are presented which show that most widespread dimensioning rules are overcritical. For high-resolution CR SAR ADCs in current CMOS technologies, matching of the capacitors, influenced by local mismatch and parasitics, is a limiting factor. For high-resolution medium-speed CR SAR ADCs, a novel capacitance array based approach using in-field calibration is proposed. This architecture promises a high resolution with small unit capacitances and without expensive factory calibration as laser trimming.
Dostawca treści:: Biblioteka Nauki