6,803 research outputs found
Analysis and Geometric Optimization of Single Electron Transistors for Read-Out in Solid-State Quantum Computing
The single electron transistor (SET) offers unparalled opportunities as a
nano-scale electrometer, capable of measuring sub-electron charge variations.
SETs have been proposed for read-out schema in solid-state quantum computing
where quantum information processing outcomes depend on the location of a
single electron on nearby quantum dots. In this paper we investigate various
geometries of a SET in order to maximize the device's sensitivity to charge
transfer between quantum dots. Through the use of finite element modeling we
model the materials and geometries of an Al/Al2O3 SET measuring the state of
quantum dots in the Si substrate beneath. The investigation is motivated by the
quest to build a scalable quantum computer, though the methodology used is
primarily that of circuit theory. As such we provide useful techniques for any
electronic device operating at the classical/quantum interface.Comment: 13 pages, 17 figure
Synchronization reveals topological scales in complex networks
We study the relationship between topological scales and dynamic time scales
in complex networks. The analysis is based on the full dynamics towards
synchronization of a system of coupled oscillators. In the synchronization
process, modular structures corresponding to well defined communities of nodes
emerge in different time scales, ordered in a hierarchical way. The analysis
also provides a useful connection between synchronization dynamics, complex
networks topology and spectral graph analysis.Comment: 4 pages, 3 figure
Some injector element detail effects on screech in hydrogen-oxygen rockets
An experimental investigation was conducted to learn more about how the specific details of a concentric tube injection element affect the screech characteristics of a hydrogen-oxygen rocket engine. The four variables investigated were (1) impingement angle, (2) oxidizer tube blunt base thickness, (3) oxidizer tube recess and extension, and (4) oxidizer tube-annulus concentricity. Tests were made using a 27.34-cm (10.77-in.) diameter heat sink combustor at nominally 300-psia chamber pressure. All of the test variables were investigated using a 157 element circular pattern injector. Additional oxidizer tube recess tests were made with a 421 element hexagonal pattern injector. Tests were conducted over the oxidant-fuel ratio range of 4 to 6. Stability evaluation for each configuration was made using the hydrogen temperature rating technique. Several element configurations were also cold flow tested using nitrogen and water as simulants. The element detail changes resulted in changes in hydrogen injector pressure drop even though the physical injection area was constant for all similar tests in both hot firing and cold flow tests. These changes in injector pressure drop produced changes in combustion stability. The data were correlated with a modified version of a previously reported injection area ratio correlation. By interpreting changes in injector pressure drop as changes in injector hydrogen flow resistance, the data were compared with a hydrogen flow response stability model and were found to be in agreement
A Three Monoclonal Antibody Combination Potently Neutralizes Multiple Botulinum Neurotoxin Serotype E Subtypes.
Human botulism is most commonly caused by botulinum neurotoxin (BoNT) serotypes A, B, and E. For this work, we sought to develop a human monoclonal antibody (mAb)-based antitoxin capable of binding and neutralizing multiple subtypes of BoNT/E. Libraries of yeast-displayed single chain Fv (scFv) antibodies were created from the heavy and light chain variable region genes of humans immunized with pentavalent-toxoid- and BoNT/E-binding scFv isolated by Fluorescence-Activated Cell Sorting (FACS). A total of 10 scFv were isolated that bound one or more BoNT/E subtypes with nanomolar-level equilibrium dissociation constants (KD). By diversifying the V-regions of the lead mAbs and selecting for cross-reactivity, we generated three scFv that bound all four BoNT/E subtypes tested at three non-overlapping epitopes. The scFvs were converted to IgG that had KD values for the different BoNT/E subtypes ranging from 9.7 nM to 2.28 pM. An equimolar combination of the three mAbs was able to potently neutralize BoNT/E1, BoNT/E3, and BoNT/E4 in a mouse neutralization assay. The mAbs have potential utility as therapeutics and as diagnostics capable of recognizing multiple BoNT/E subtypes. A derivative of the three-antibody combination (NTM-1633) is in pre-clinical development with an investigational new drug (IND) application filing expected in 2018
Coherent Tunneling Adiabatic Passage with the Alternating Coupling Scheme
The use of adiabatic passage techniques to mediate particle transport through
real space, rather than phase space is becoming an interesting possibility. We
have investigated the properties of Coherent Tunneling Adiabatic Passage (CTAP)
with alternating tunneling matrix elements. This geometry, not previously
considered in the donor in silicon paradigm, provides an interesting route to
long-range quantum transport. We introduce simplified coupling protocols, and
transient eigenspectra as well as a realistic gate design for this transport
protocol. Using a pairwise treatment of the tunnel couplings for a 5 donor
device with 30nm donor spacings, 120nm total chain length, we estimate the time
scale required for adiabatic operation to be ~70ns, a time well within measured
electron spin and estimated charge relaxation and times for phosphorus donors
in silicon.Comment: 13 pages, 5 figures, minor revision
ACAS-Xu Run 5 HITL (June 2019) SC-228 WG 1.3 Results Outbrief
This presentation provides an overview of a recently completed human-in-the-loop simulation, conducted as part of the Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project. This study examined how to present resolution advisories (RAs) issued by Airborne Collision Avoidance System (ACAS) Xu, which can be in the vertical dimension, the horizontal dimension, or both (i.e., blended). The study varied the location of the ACAS Xu traffic information - it was either presented within an 'integrated' display or a 'standalone' display, where the traffic information was separated from the vehicle control interfaces and navigational information. Results revealed generally positive feedback on the visual and aural presentation of RAs, with special considerations and performance implications noted throughout
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