2,702 research outputs found
Carbon nanotube electron gun
An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun
Thermal kinetic inductance detectors for ground-based millimeter-wave cosmology
We show measurements of thermal kinetic inductance detectors (TKID) intended
for millimeter wave cosmology in the 200-300 GHz atmospheric window. The TKID
is a type of bolometer which uses the kinetic inductance of a superconducting
resonator to measure the temperature of the thermally isolated bolometer
island. We measure bolometer thermal conductance, time constant and noise
equivalent power. We also measure the quality factor of our resonators as the
bath temperature varies to show they are limited by effects consistent with
coupling to two level systems.Comment: 8 pages, 4 figures. Submitted to Journal of Low Temperature Physic
Carbon Nanotube Electron Gun
An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun
Direct measurements of DOCO isomers in the kinetics of OD+CO
Quantitative and mechanistically-detailed kinetics of the reaction of
hydroxyl radical (OH) with carbon monoxide (CO) have been a longstanding goal
of contemporary chemical kinetics. This fundamental prototype reaction plays an
important role in atmospheric and combustion chemistry, motivating studies for
accurate determination of the reaction rate coefficient and its pressure and
temperature dependence at thermal reaction conditions. This intricate
dependence can be traced directly to details of the underlying dynamics
(formation, isomerization, and dissociation) involving the reactive
intermediates cis- and trans-HOCO, which can only be observed transiently.
Using time-resolved frequency comb spectroscopy, comprehensive mechanistic
elucidation of the kinetics of the isotopic analogue deuteroxyl radical (OD)
with CO has been realized. By monitoring the concentrations of reactants,
intermediates, and products in real-time, the branching and isomerization
kinetics and absolute yields of all species in the OD+CO reaction are
quantified as a function of pressure and collision partner.Comment: 19 pages, 4 figure
Recommended from our members
The Kauffman Bracket and Genus of Alternating Links
Giving a knot, there are three rules to help us finding the Kauffman bracket polynomial. Choosing knot’s orientation, then applying the Seifert algorithm to find the Euler characteristic and genus of its surface. Finally finding the relationship of the Kauffman bracket polynomial and the genus of the alternating links is the main goal of this paper
Gammaherpesvirus modulation of mouse adenovirus type 1 pathogenesis
AbstractImmune function is likely to be shaped by multiple infections over time. Infection with one pathogen can confer cross-protection against heterologous pathogens. We tested the hypothesis that latent murine gammaherpesvirus 68 (γHV68) infection modulates host inflammatory responses and susceptibility to mouse adenovirus type 1 (MAV-1). Mice were infected intranasally (i.n.) with γHV68. 21 days later, they were infected i.n. with MAV-1. We assessed cytokine and chemokine expression by quantitative reverse transcriptase real-time PCR, cellular inflammation by histology, and viral loads by quantitative real-time PCR. Previous γHV68 infection led to persistently upregulated IFN-γ in lungs and spleen and persistently upregulated CCL2 and CCL5 in the lungs. Previous γHV68 infection amplified MAV-1-induced CCL5 upregulation and cellular inflammation in the lungs. Previous γHV68 infection was associated with lower MAV-1 viral loads in the spleen but not the lung. There was no significant effect of previous γHV68 on IFN-γ expression or MAV-1 viral loads when the interval between infections was increased to 44 days. In summary, previous γHV68 infection modulated lung inflammatory responses and decreased susceptibility to a heterologous virus in an organ- and time-dependent manner
Top- Ranking Bayesian Optimization
This paper presents a novel approach to top- ranking Bayesian optimization
(top- ranking BO) which is a practical and significant generalization of
preferential BO to handle top- ranking and tie/indifference observations. We
first design a surrogate model that is not only capable of catering to the
above observations, but is also supported by a classic random utility model.
Another equally important contribution is the introduction of the first
information-theoretic acquisition function in BO with preferential observation
called multinomial predictive entropy search (MPES) which is flexible in
handling these observations and optimized for all inputs of a query jointly.
MPES possesses superior performance compared with existing acquisition
functions that select the inputs of a query one at a time greedily. We
empirically evaluate the performance of MPES using several synthetic benchmark
functions, CIFAR- dataset, and SUSHI preference dataset.Comment: 35th AAAI Conference on Artificial Intelligence (AAAI 2021), Extended
version with derivations, 13 page
User Research for Youth Sports Division Website: Prince George’s County Department of Parks and Recreation
Final project for INST490: Integrated Capstone for
Information Science (Fall 2019). University of Maryland, College Park.In the last legislative session, a new Maryland law was passed addressing youth sports
delivery that presents an exciting new challenge for the Prince George’s County Department of
Parks and Recreation.
The Department is in the process of establishing a new division to meet this challenge
while continuing to deliver a wide variety of sports through in-house programs and with
partnership organizations. The new Division will feature “one stop shopping” enabling
community members to to view schedules, register their children, and learn about
opportunities for engagement.
This project’s survey was developed to gather community input to that can inform what
content would best serve users.Prince George's Count
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