1,662 research outputs found
Design and evaluation of a virtual gearshift application
When a customer buys a new car, he or she wants it to address personal preferences with respect to its driving behavior. By utilizing virtual reality technology, a virtual prototyping environment (VPE) can be created in which the behavior of a vehicle or part of a vehicle can be evaluated and adjusted to match the driver's desires. This paper describes the design and the evaluation of a VPE for manually operated gearboxes. The test group considered the simulated "virtual" gearshift feel to be quite similar to the "real" gearshift feel of a test vehicle. By further developing this VPE, it should become possible to define gearshift feel by customer assessment through haptic simulation, after which the physical gearbox is designed in such a way that it matches the preferred shifting behavior
Observing Zitterbewegung for photons near the Dirac point of a two-dimensional photonic crystal
It is shown, for the first time, that the zitterbewegung of photon can appear
near the Dirac point in two-dimensional photonic crystal. The superiority of
such a phenomenon for photons is that it can be found in different scaling
structures with wide frequency regions. It can be observed by measuring the
time dependence of the transmission coefficient through photonic crystal slabs.
Thus, it is particularly suited for experimentally observing this effect. We
have observed such a phenomenon by exact numerical simulations, confirming a
long-standing theoretical prediction
Magnetic Kronig-Penney model for Dirac electrons in single-layer graphene
The properties of Dirac electrons in a magnetic superlattice (SL) on graphene
consisting of very high and thin (delta-function) barriers are investigated. We
obtain the energy spectrum analytically and study the transmission through a
finite number of barriers. The results are contrasted with those for electrons
described by the Schrodinger equation. In addition, a collimation of an
incident beam of electrons is obtained along the direction perpendicular to
that of the SL. We also highlight the analogy with optical media in which the
refractive index varies in space.Comment: 21 pages, 13 figures, to appear in New Journal of Physic
Charge transport through weakly open one dimensional quantum wires
We consider resonant transmission through a finite-length quantum wire
connected to leads via finite transparency junctions. The coherent electron
transport is strongly modified by the Coulomb interaction. The low-temperature
current-voltage () curves show step-like dependence on the bias voltage
determined by the distance between the quantum levels inside the conductor, the
pattern being dependent on the ratio between the charging energy and level
spacing. If the system is tuned close to the resonance condition by the gate
voltage, the low-voltage curve is Ohmic. At large Coulomb energy and low
temperatures, the conductance is temperature-independent for any relationship
between temperature, level spacing, and coupling between the wire and the
leads
Intraband electron focusing in bilayer graphene
We propose an implementation of a valley selective electronic Veselago lens
in bilayer graphene. We demonstrate that in the presence of an appropriately
oriented potential step, low-energy electrons radiating from a point source can
be re-focused coherently within the same band. The phenomenon is due to the
trigonal warping of the band structure that leads to a negative refraction
index. We show that the interference pattern can be controlled by an external
mechanical strain.Comment: 14 pages, 8 figure
Efficient processing of TFO-directed psoralen DNA interstrand crosslinks by the UvrABC nuclease
Photoreactive psoralens can form interstrand crosslinks (ICLs) in double-stranded DNA. In eubacteria, the endonuclease UvrABC plays a key role in processing psoralen ICLs. Psoralen-modified triplex-forming oligonucleotides (TFOs) can be used to direct ICLs to specific genomic sites. Previous studies of pyrimidine-rich methoxypsoralenāmodified TFOs indicated that the TFO inhibits cleavage by UvrABC. Because different chemistries may alter the processing of TFO-directed ICLs, we investigated the effect of another type of triplex formed by purine-rich TFOs on the processing of 4ā²-(hydroxymethyl)-4,5ā²,8-trimethylpsoralen (HMT) ICLs by the UvrABC nuclease. Using an HMT-modified TFO to direct ICLs to a specific site, we found that UvrABC made incisions on the purine-rich strand of the duplex ā¼3 bases from the 3ā²-side and ā¼9 bases from the 5ā²-side of the ICL, within the TFO-binding region. In contrast to previous reports, the UvrABC nuclease cleaved the TFO-directed psoralen ICL with a greater efficiency than that of the psoralen ICL alone. Furthermore, the TFO was dissociated from its duplex binding site by UvrA and UvrB. As mutagenesis by TFO-directed ICLs requires nucleotide excision repair, the efficient processing of these lesions supports the use of triplex technology to direct DNA damage for genome modification
- ā¦