Skyrmionic textures in chiral magnets

In non-centrosymmetric magnets the chiral Dzyaloshinskii-Moriya exchange stabilizes Skyrmion-strings as excitations which may condense into multiply modulated phases. Such extended Skyrmionic textures are determined by the stability of the localized "solitonic" Skyrmion cores and their geometrical incompatibility which frustrates regular space-filling. We present numerically exact solutions for Skyrmion lattices and formulate basic properties of the Skyrmionic states.Comment: Conference information: The International Conference on Magnetism (ICM), Karlsruhe, July 26 - 31, 200

Theory of vortex states in magnetic nanodisks with induced Dzyaloshinskii-Moriya interactions

Vortex states in magnetic nanodisks are essentially affected by surface/interface induced Dzyaloshinskii-Moriya interactions. Within a micromagnetic approach we calculate the equilibrium sizes and shape of the vortices as functions of magnetic field, the material and geometrical parameters of nanodisks. It was found that the Dzyaloshinskii-Moriya coupling can considerably increase sizes of vortices with "right" chirality and suppress vortices with opposite chirality. This allows to form a bistable system of homochiral vortices as a basic element for storage applications.Comment: 8 pages, 8 figure

Thermal Wave Induced Edge Electrical Field of Pyroelectric: Spatial Pattern Mapping and Effect of Ambient Conditions

We have recently analyzed theoretically the main characteristics of the edge depolarizing electric field (EDEF), in the vicinity of a non-polar face of a pyroelectric. In this work we measured and characterized the EDEF, excited by a harmonical thermal wave. We present here experimental results obtained on a pyroelectric crystal LiTaO3, confirming our theoretical predictions. We present the theoretical analysis and description of the thermal wave and the induced harmonically varying EDEF. The calculations assume an equivalent circuit of a pyroelectric capacitive current source. The measured magnitude of the EDEF and its spatial variation agree well with the theoretical model. The effect of the air pressure at the pyroelectric/air interface, on the EDEF, was determined in the interval 10^3 - 10^-6 torr. We found that EDEF increases significantly with decreasing air pressure, presumably due to diminishing of adsorption screening at the polar faces. Teflon plates, covering the polar faces, prevent accumulation of screening charged particles, resulting in a drastic increase of EDEF

Study of rotational isomerism in arylmethanesulfonates

In solution, the arylmethanesulfonates exist as two conformers with the methyl and aryl radicals in gauche and trans configurations. © 1979 Plenum Publishing Corporation

Investigation of the steric structure of certain compounds of the bicyclo-[4,2,0]octan-7-one series

1. The steric structure of adducts of dichloroketene and cyclohexene, dichloroketene and methyl-cyclohexene, dimethylketene and dihydropyran was investigated by the methods of dipole moments and molar Kerr constants. 2. For all the adducts, the preferential conformation of the bicyclo[4,2,0]octan-7-one system is the anti-boat conformation. 3. The adduct of dimethylketene and dihydropyran has the structure of 8,8-dimethyl-2-oxobicyclo-[4,2,0] octan-7-one. The formation of such a structure is apparently determined by the electron donor influence of the oxygen atom in dihydropyran on the process of cycloaddition. © 1974 Consultants Bureau

Three-dimensional structures of some perhydro-1,4-thiazine derivatives

A number of perhydro-1,4-thiazine S-oxides and S,S-dioxides were synthesized. Their IR and PMR spectra were studied, and their dipole moments were determined. The latter were compared with the calculated values for the chair conformation with various orientations of the substituents. Conclusions were drawn regarding the configuration and conformation of the investigated compounds. © 1974 Consultants Bureau

Electron transport in a slot-gate Si MOSFET

The transversal and longitudinal resistance in the quantum Hall effect regime was measured in a Si MOSFET sample in which a slot-gate allows one to vary the electron density and filling factor in different parts of the sample. In case of unequal gate voltages, the longitudinal resistances on the opposite sides of the sample differ from each other because the originated Hall voltage difference is added to the longitudinal voltage only on one side depending on the gradient of the gate voltages and the direction of the external magnetic field. After subtracting the Hall voltage difference, the increase in longitudinal resistance is observed when electrons on the opposite sides of the slot occupy Landau levels with different spin orientations.Comment: To appear in Europhys. Let

Microarray-based method for detection of unknown genetic modifications

<p>Abstract</p> <p>Background</p> <p>Due to the increased use of genetic modifications in crop improvement, there is a need to develop effective methods for the detection of both known and unknown transgene constructs in plants. We have developed a strategy for detection and characterization of unknown genetic modifications and we present a proof of concept for this method using <it>Arabidopsis thaliana </it>and <it>Oryza sativa </it>(rice). The approach relies on direct hybridization of total genomic DNA to high density microarrays designed to have probes tiled throughout a set of reference sequences.</p> <p>Results</p> <p>We show that by using arrays with 25 basepair probes covering both strands of a set of 235 vectors (2 million basepairs) we can detect transgene sequences in transformed lines of <it>A. thaliana </it>and rice without prior knowledge about the transformation vectors or the T-DNA constructs used to generate the studied plants.</p> <p>Conclusion</p> <p>The approach should allow the user to detect the presence of transgene sequences and get sufficient information for further characterization of unknown genetic constructs in plants. The only requirements are access to a small amount of pure transgene plant material, that the genetic construct in question is above a certain size (here ≥ 140 basepairs) and that parts of the construct shows some degree of sequence similarity with published genetic elements.</p