1,076 research outputs found
Technological survey of tellurium and its compounds
Review includes data on the chemical and physical properties of tellurium, its oxides, and fluorides, pertinent to the process problem of handling fission product tellurium in fluoride form. The technology of tellurium handling in nonaqueous processing of nuclear fuels is also reviewed
Study of loss in superconducting coplanar waveguide resonators
Superconducting coplanar waveguide (SCPW) resonators have a wide range of
applications due to the combination of their planar geometry and high quality
factors relative to normal metals. However, their performance is sensitive to
both the details of their geometry and the materials and processes that are
used in their fabrication. In this paper, we study the dependence of SCPW
resonator performance on materials and geometry as a function of temperature
and excitation power. We measure quality factors greater than at
high excitation power and at a power comparable to that generated
by a single microwave photon circulating in the resonator. We examine the
limits to the high excitation power performance of the resonators and find it
to be consistent with a model of radiation loss. We further observe that while
in all cases the quality factors are degraded as the temperature and power are
reduced due to dielectric loss, the size of this effect is dependent on
resonator materials and geometry. Finally, we demonstrate that the dielectric
loss can be controlled in principle using a separate excitation near the
resonance frequencies of the resonator.Comment: Replacing original version. Changes made based on referee comments.
Fixed typo in equation (3) and added appendi
Proximity-Coupled Ti/TiN Multilayers for use in Kinetic Inductance Detectors
We apply the superconducting proximity effect in TiN/Ti multi-layer films to
tune the critical temperature, Tc, to within 10 mK with high uniformity (less
than 15 mK spread) across a 75 mm wafer. Reproducible Tc's are obtained from
0.8 - 2.5 K. These films had high resistivities, > 100 uOhm-cm and internal
quality factors for resonators in the GHz range on the order of 100k and
higher. Both trilayers of TiN/Ti/TiN and thicker superlattice films were
prepared, demonstrating a highly controlled process for films over a wide
thickness range. Detectors were fabricated and showed single photon resolution
at 1550 nm. The high uniformity and controllability coupled with the high
quality factor, kinetic inductance, and inertness of TiN make these films ideal
for use in frequency multiplexed kinetic inductance detectors and other
potential applications such as nanowire detectors, transition edge sensors and
associated quantum information applications
Sub-micrometer epitaxial Josephson junctions for quantum circuits
We present a fabrication scheme and testing results for epitaxial
sub-micrometer Josephson junctions. The junctions are made using a
high-temperature (1170 K) "via process" yielding junctions as small as 0.8 mu m
in diameter by use of optical lithography. Sapphire (Al2O3) tunnel-barriers are
grown on an epitaxial Re/Ti multilayer base-electrode. We have fabricated
devices with both Re and Al top electrodes. While room-temperature (295 K)
resistance versus area data are favorable for both types of top electrodes, the
low-temperature (50 mK) data show that junctions with the Al top electrode have
a much higher subgap resistance. The microwave loss properties of the junctions
have been measured by use of superconducting Josephson junction qubits. The
results show that high subgap resistance correlates to improved qubit
performance
The Human leading the Thermal Comfort Control
Many buildings were designed and calculated by advanced software tools and simulation tools. However in real
practice these buildings do not achieve the calculated energy efficiency, but use up to 40 to 50% more energy. One of the
reasons for the discrepant ion between designed performance and real performance is the human behavior of which no real
adequate integration into the design tools exists Therefore new design approaches are needed to implement the real
behavior of occupants of buildings. Human-in-the-loop Technology is developed; a technology to implement user
behavior. By starting from the human perspective and use available and new technology, we determined the critical
performance indicators for the perceived human comfort. To further optimize the performance of these systems, further
development is done into the possibilities and use of infra red heating systems for individual comfort control on workplace
level
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