1,467 research outputs found
Theoretical Engineering and Satellite Comlink of a PTVD-SHAM System
This paper focuses on super helical memory system's design, 'Engineering,
Architectural and Satellite Communications' as a theoretical approach of an
invention-model to 'store time-data'. The current release entails three
concepts: 1- an in-depth theoretical physics engineering of the chip including
its, 2- architectural concept based on VLSI methods, and 3- the time-data
versus data-time algorithm. The 'Parallel Time Varying & Data Super-helical
Access Memory' (PTVD-SHAM), possesses a waterfall effect in its architecture
dealing with the process of voltage output-switch into diverse logic and
quantum states described as 'Boolean logic & image-logic', respectively.
Quantum dot computational methods are explained by utilizing coiled carbon
nanotubes (CCNTs) and CNT field effect transistors (CNFETs) in the chip's
architecture. Quantum confinement, categorized quantum well substrate, and
B-field flux involvements are discussed in theory. Multi-access of coherent
sequences of 'qubit addressing' in any magnitude, gained as pre-defined, here
e.g., the 'big O notation' asymptotically confined into singularity while
possessing a magnitude of 'infinity' for the orientation of array displacement.
Gaussian curvature of k(k<0) is debated in aim of specifying the
2D electron gas characteristics, data storage system for defining short and
long time cycles for different CCNT diameters where space-time continuum is
folded by chance for the particle. Precise pre/post data timing for, e.g.,
seismic waves before earthquake mantle-reach event occurrence, including time
varying self-clocking devices in diverse geographic locations for radar systems
is illustrated in the Subsections of the paper. The theoretical fabrication
process, electromigration between chip's components is discussed as well.Comment: 50 pages, 10 figures (3 multi-figures), 2 tables. v.1: 1 postulate
entailing hypothetical ideas, design and model on future technological
advances of PTVD-SHAM. The results of the previous paper [arXiv:0707.1151v6],
are extended in order to prove some introductory conjectures in theoretical
engineering advanced to architectural analysi
Comparison of spinal cord stimulation profiles from intra- and extradural electrode arrangements by finite element modelling
Spinal cord stimulation currently relies on extradural electrode arrays that are separated from the spinal cord surface by a highly conducting layer of cerebrospinal fluid. It has recently been suggested that intradural placement of the electrodes in direct contact with the pial surface could greatly enhance the specificity and efficiency of stimulation. The present computational study aims at quantifying and comparing the electrical current distributions as well as the spatial recruitment profiles resulting from extra- and intra-dural electrode arrangements. The electrical potential distribution is calculated using a 3D finite element model of the human thoracic spinal canal. The likely recruitment areas are then obtained using the potential as input to an equivalent circuit model of the pre-threshold axonal response. The results show that the current threshold to recruitment of axons in the dorsal column is more than an order of magnitude smaller for intradural than extradural stimulation. Intradural placement of the electrodes also leads to much higher contrast between the stimulation thresholds for the dorsal root entry zone and the dorsal column, allowing better focusing of the stimulus
Personalizing Simulations of the Human Atria : Intracardiac Measurements, Tissue Conductivities, and Cellular Electrophysiology
This work addresses major challenges of heart model personalization. Analysis techniques for clinical intracardiac electrograms determine wave direction and conduction velocity from single beats. Electrophysiological measurements are simulated to validate the models. Uncertainties in tissue conductivities impact on simulated ECGs. A minimal model of cardiac myocytes is adapted to the atria. This makes personalized cardiac models a promising technique to improve treatment of atrial arrhythmias
A Probabilistic Model for Estimating the Depth and Threshold Temperature of C-fiber Nociceptors
The subjective experience of thermal pain follows the detection and encoding
of noxious stimuli by primary afferent neurons called nociceptors. However,
nociceptor morphology has been hard to access and the mechanisms of signal
transduction remain unresolved. In order to understand how heat transducers in
nociceptors are activated in vivo, it is important to estimate the
temperatures that directly activate the skin-embedded nociceptor membrane.
Hence, the nociceptor’s temperature threshold must be estimated, which in turn
will depend on the depth at which transduction happens in the skin. Since the
temperature at the receptor cannot be accessed experimentally, such an
estimation can currently only be achieved through modeling. However, the
current state-of-the-art model to estimate temperature at the receptor suffers
from the fact that it cannot account for the natural stochastic variability of
neuronal responses. We improve this model using a probabilistic approach which
accounts for uncertainties and potential noise in system. Using a data set of
24 C-fibers recorded in vitro, we show that, even without detailed knowledge
of the bio-thermal properties of the system, the probabilistic model that we
propose here is capable of providing estimates of threshold and depth in cases
where the classical method fails
Interacting gases of ultracold polar molecules
Ultracold quantum gases are versatile model systems for exploring quantum physics or for the simulation of solid state materials. Meanwhile, they have been created from various atomic species - from alkali metals over alkaline earths to rare earth elements. The latest addition are quantum gases of different kinds of polar molecules. Expectations for quantum gases of heteronuclear molecules are high: Due to their large electric dipole moments, these molecules can interact with each other via long-range interactions - not just via contact interactions as is the case for most atoms. Additionally, they have vibrational and rotational degrees of freedom, with open up new possibilities for quantum simulation.
But the same degrees of freedom also pose some challenges. For example, they make the preparation of the quantum gas more difficult, which is typically produced with a combination of laser cooling and evaporative cooling in the atomic case. Molecules mostly lack closed transitions in their spectra, which are required for laser cooling. Therefore, we create our molecular quantum gas from a mixture of two atomic quantum gases.
In this work, such an experimental method was developed for fermionic NaK molecules, which is based on the two-photon process Stimulated Raman Adiabatic Passage (STIRAP). Within STIRAP, the hyperfine structure of the chosen intermediate state plays an important role. Experimentally, and with the help of a theoretical model describing the whole process, we find that we produce the most molecules when we use a large one-photon detuning, if the hyperfine structure of the intermediate state is unresolved.
In another project, we explored the rotational level structure of the molecular ground state populated by STIRAP. Rotation is closely linked to the electric dipole moment. The superposition of the ground state with the first excited rotational state, for example, has a transition dipole moment of almost 60% of the permanent electric dipole moment. Unfortunately, coherence times of such superpositions are typically short, as the different polarizabilities of the rotational states lead to dephasing in optical traps. However, using a special polarization angle and a small, dc electric field, we can compensate these differences and realize a spin-decoupled magic trap. With this new technique we obtain record coherence times, at least for small molecular densities.
For larger densities we observe first indications for dipolar interactions in a bulk gas of polar molecules, which we also model using the moving-average cluster expansion (MACE)
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