15 research outputs found
Observation of cyclotron resonance in an InAs/GaAs wetting layer with shallowly formed quantum dots
A practical guide to single-cell RNA-sequencing for biomedical research and clinical applications.
RNA sequencing (RNA-seq) is a genomic approach for the detection and quantitative analysis of messenger RNA molecules in a biological sample and is useful for studying cellular responses. RNA-seq has fueled much discovery and innovation in medicine over recent years. For practical reasons, the technique is usually conducted on samples comprising thousands to millions of cells. However, this has hindered direct assessment of the fundamental unit of biology-the cell. Since the first single-cell RNA-sequencing (scRNA-seq) study was published in 2009, many more have been conducted, mostly by specialist laboratories with unique skills in wet-lab single-cell genomics, bioinformatics, and computation. However, with the increasing commercial availability of scRNA-seq platforms, and the rapid ongoing maturation of bioinformatics approaches, a point has been reached where any biomedical researcher or clinician can use scRNA-seq to make exciting discoveries. In this review, we present a practical guide to help researchers design their first scRNA-seq studies, including introductory information on experimental hardware, protocol choice, quality control, data analysis and biological interpretation
Acoustic Phonon Activated and Assisted Tunnelling in Ge:Sb,P
The influence of lattice vibrations on the field ionization rate of shallow donors in germanium at low lattice temperatures is investigated experimentally and theoretically. The role played by acoustic phonons in the tunnelling of electrons from the ground donor level (phonon assisted tunnelling) and through the excited donor levels (phonon activated tunnelling) is considered. Both processes are shown to enhance the tunnelling rate
Field Ionization of Shallow Acceptors
Experimental studies on hole tunneling from the substitutional boron impurity into degenerate valence band of silicon single crystals are presented. The results are interpreted within the framework of acceptor ground state quartet splitting into the Kramers doublet due to presence of random strains and electric field in the lattice
Investigation of Magnetoresistance and Its Anisotropy of Thin Polycrystalline Films in High Pulsed Magnetic Fields
The results on the study of grain boundary effects and influence of film deposition conditions on the magnetoresistance and its anisotropy in polycrystalline films are presented. The magnetoresistance was measured in high pulsed magnetic fields up to 25 T (pulse duration ≈ 0.6 ms) in the temperature range of 120-300 K. A modified Mott hopping model was applied to describe the main behavior of high-field magnetoresistance for both ferromagnetic and paramagnetic phases of the polycrystalline films by taking into account the demagnetization field of the films measured in low magnetic fields perpendicular to film plane. It was also found that to obtain the higher magnetoresistance saturation field at room temperature it is necessary to use the films with smaller crystallites (D ≈ 100 nm). Such films could be used for design of megagauss pulsed magnetic field sensors
Ageing effects on electrical resistivity and magnetoresistance of nanostructured manganite films
Numerical Magneto-Mechanical Analysis of Destructive Coils with Reinforcement Cylinders of Various Thicknesses
The destructive laboratory device, generating half-period sinus-shaped magnetic field pulses of 0.15-2 ms duration is investigated numerically. The coil was placed into a steel reinforcement cylinder to resist magnetic forces, while influence of thickness of the reinforcement cylinder is considered in detail. The time-dependent non-linear magneto-mechanical model and the finite element software ANSYS are employed. On the basis of the mechanical analysis, reasonable explanation of the destruction nature is provided. The numerically obtained operation threshold value was in good agreement with experimental measurements
Influence of Sr Content on CMR Effect in Polycrystalline Thin Films
The magnetoresistance of thin polycrystalline films deposited on lucalox substrate using metal organic chemical vapor deposition technique was investigated in pulsed magnetic fields up to 18 T in the temperature range 100-320 K. The influence of film preparation conditions, ambient temperature variation and Sr content is analyzed in order to determine the optimal conditions for the design of CMR-B-scalar magnetic field sensor based on thin manganite film, operating at room temperature
Magneto- and Electroresistance of Ultrathin Anisotropically Strained La-Sr-MnO Films
The magnetoresistance anisotropy of ultrathin LaSrMn O films deposited on NdGaO substrate by metalorganic chemical vapour deposition technique was investigated. The electric-field-induced resistance change was studied up to electric fields of 10 kV/cm using ns duration electrical pulses. It was found that in ultrathin (< 10 nm) and thin (< 50 nm) films the origin of electric-field-induced resistance change is thermal. However, the films with thicknesses of about 20 nm, exhibit negative electric-field-induced resistance change, having a pure electronic nature. This effect is explained in terms of two-layer systems with imperfections located at the interface between the layers
Electroresistance of La-Ca-MnO Thin Films
Epitaxial, textured, and polycrystalline LaCaMn O films, having about 150 nm thickness, were prepared by pulsed laser deposition techniques onto (110) NdGaO, MgO and lucalox substrates and investigated using 10 ns duration, 0.5 ns rise time electrical pulses having amplitude up to 500 V. Electroresistance of the films [R(E)-R(0)]/R(0) was investigated up to 80 kV/cm electric field strengths in temperatures ranging from 300 K to 4.2 K. Strong (up to 93%) negative electroresistance was obtained in polycrystalline LaCaMnO films prepared on MgO and lucalox substrates. The epitaxial films grown on NdGaO substrate demonstrated only a small resistance change due to Joule heating induced by a current pulse. It was concluded that electroresistance manifests itself in strongly inhomogeneous manganites films exhibiting a large number of structural imperfections producing ferromagnetic tunnel junction nets