781 research outputs found
Approaches and possible improvements in the area of multibody dynamics modeling
A wide ranging look is taken at issues involved in the dynamic modeling of complex, multibodied orbiting space systems. Capabilities and limitations of two major codes (DISCOS, TREETOPS) are assessed and possible extensions to the CONTOPS software are outlined. In addition, recommendations are made concerning the direction future development should take in order to achieve higher fidelity, more computationally efficient multibody software solutions
Room Temperature Electrical Detection of Spin Coherence in C60
An experimental demonstration of electrical detection of coherent spin motion
of weakly coupled, localized electron spins in thin Fullerene C60 films at room
temperature is presented. Pulsed electrically detected magnetic resonance
experiments on vertical photocurrents through Al/C60/ZnO samples showed that an
electron spin Rabi oscillation is reflected by transient current changes. The
nature of possible microscopic mechanisms responsible for this spin to charge
conversion as well as its implications for the readout of endohedral Fullerene
(N@C60) spin qubits are discussed.Comment: 4 pages, 3 figure
CW and pulsed electrically detected magnetic resonance spectroscopy at 263 GHz/12 T on operating amorphous silicon solar cells
Here we describe a new high frequency/high field continuous wave and pulsed
electrically detected magnetic resonance (CW EDMR and pEDMR) setup, operating
at 263 GHz and resonance fields between 0 and 12 T. Spin dependent transport in
illuminated hydrogenated amorphous silicon p-i-n solar cells at 5 K and 90 K
was studied by in operando 263 GHz CW and pEDMR alongside with complementary
X-band CW EDMR. Benefiting from the superior resolution at 263 GHz, we were
able to better resolve EDMR signals originating from spin dependent hopping and
recombination processes. 5 K EDMR spectra were found to be dominated by
conduction and valence band tale states involved in spin dependent hopping,
with additional contributions from triplet exciton states. 90 K EDMR spectra
could be assigned to spin pair recombination involving conduction band tail
states and dangling bonds as dominating spin dependent transport process, with
additional contributions from valence band tail and triplet exciton states.Comment: 8 pages, 4 figure
Electrostatic inactivation of RNA viruses at air-water and liquid-liquid interfaces
Understanding the interactions between viruses and surfaces or interfaces is
important, as they provide the principles underpinning the cleaning and
disinfection of contaminated surfaces. Yet, the physics of such interactions is
currently poorly understood. For instance, there are longstanding experimental
observations suggesting that the presence of air-water interfaces can
generically inactivate and kill viruses, yet the mechanism underlying this
phenomenon remains unknown. Here we use theory and simulations to show that
electrostatics provides one such mechanism, and that this is very general.
Thus, we predict that the free energy of an RNA virus should increase by
several thousands of as the virion breaches an air-water interface. We
also show that the fate of a virus approaching a generic liquid-liquid
interface depends strongly on the detailed balance between interfacial and
electrostatic forces, which can be tuned, for instance, by choosing different
media to contact a virus-laden respiratory droplet. We propose that these
results can be used to design effective strategies for surface disinfection.
Intriguingly, tunability requires electrostatic and interfacial forces to scale
similarly with viral size, which naturally occurs when charges are arranged in
a double-shell distribution as in RNA viruses like influenza and all
coronaviruses.Comment: 10 pages, 5 figures; minor corrections to the Appendi
Simulation of actively controlled spacecraft with flexible appendages
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76688/1/AIAA-25388-716.pd
Line defects in epitaxial silicon films grown at 560 C
We present an investigation of line defects in epitaxially grown silicon layers using Secco defect etching and transmission electron microscopy TEM . 1 m thick layers were deposited onto Si 100 wafers at a substrate temperature of 560 C using electron cyclotron resonance chemical vapour deposition ECRCVD . Defect etching reveals a variety of etch pits related to extended defects. A detailed analysis of the orientations and shapes of etch pits related to line defects is carried out. Using this information it is then possible to assign different types of etch pits to line defects observed by TEM. The investigations show, that one type of defect are extended dislocations parallel to lt;112 gt;, while the direction of two other types are lt;110 gt; as well as lt;314 gt;, a direction uncommon for line defects in silico
MEN-2 Syndrome: The Value of Screening and Central Registration; A Study of Six Kindreds in The Netherlands
Since 1975, six families with the MEN-2A syndrome including 66 patients have been identified in The Netherlands. All these patients underwent thyroidectomy for C-cell hyperplasia and/or medullary thyroid carcinoma (MTC); eight were symptomatic (Group A), 51 were relatives of patients found to be affected (Group B), and seven had had a negative screening test that became positive (Group C). To assess the effect of screening, we compared these groups with respect to the occurrence of metastatic MTC at thyroidectomy and the results of the postoperative calcitonin (CT) tests. We found that 87% of Group A, 37% of Group B; and none of Group C had metastatic disease at surgery. The cure rates in these three groups with MEN-2A, as determined by stimulated CT measurement, was 0%, 51%, and 100%, respectively. From these results it may be concluded that screening can lead to the detection of MTC at an earlier stage which in turn could permit curative treatment and improvement of both prognosis and life expectancy. The need for supervision of affected families by central registration to guarantee the continuity of screening is stressed
Impact of prevalent and incident vertebral fractures on utility: results from a patient-based and a population-based sample
Data are scarce on the impact of vertebral fractures (VFX) on utility. The objective of this study was to assess the impact
of prevalent and incident VFX on utility in both a patient-based and population-based sample. Data from the Multiple Outcomes
of Raloxifene Evaluation (MORE) study (n = 550 for prevalent VFX and n = 174 for incident VFX) and the European Prospective Osteoporosis Study (EPOS) (n = 236) were used. Utility was assessed by the index score of the EQ-5D. In the MORE study, highly statistically significant
associations were found between utility and the presence of prevalent VFX (p < 0.001), number of prevalent VFX (p < 0.001), severity of prevalent VFX (p < 0.001), the combination of number and severity of prevalent VFX (p = 0.001) and location of prevalent VFX (p = 0.019). The mean utility was significantly lower among women who suffered an incident VFX (utility = 0.67) than among women
who did not (utility = 0.77) (p = 0.005), although utility loss was not significantly different between the two groups (p = 0.142). In EPOS, the combination of number and severity of incident VFX was significantly related to utility (p = 0.030). In conclusion, utility is lower among persons with prevalent and incident VFX, especially in a patient-based sample.
Utility loss was not significantly different between women without and with incident VFX
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