1,225 research outputs found
Massenspektrometrische Untersuchungen der aus Additiven in nasslaufenden Lamellenkupplungen gebildeten tribologischen Grenzschichten
Die hauptsĂ€chlich aus Additiven an den ReibkörperoberflĂ€chen nasslaufender Lamellenkupplungen gebildeten tribologischen Grenzschichten besitzen einen erheblichen Einfluss auf das Reibungsverhalten des tribologischen Systems. Kombinierte Untersuchungen aus PrĂŒfstandsversuchen und ToF-SIMS-Analysen können wertvolle Erkenntnisse zu den Bildungsmechanismen und den Auswirkungen solcher tribologischen Grenzschichten liefern. Die vorliegende Arbeit befasst sich eingehend mit den massenspektrometrischen Untersuchungen der wĂ€hrend PrĂŒfstandsversuchen an StahllamellenoberflĂ€chen gebildeten tribologischen Grenzschichten, unter Verwendung eines organischen Reibbelags und 14 verschiedener Modellfluide. Die Ergebnisse verbessern das VerstĂ€ndnis des tribologischen Grenzschichtaufbaus, sie gewĂ€hren Einblicke in Additiv-Additiv-Wechselwirkungen wĂ€hrend der tribologischen Belastung und ermöglichen auĂerdem RĂŒckschlĂŒsse zu Auswirkungen von Grenzschichtbestandteilen auf die Reibungscharakteristik
Fabrication of high quality plan-view TEM specimens using the focused ion beam
We describe a technique using a focused ion beam instrument to fabricate high quality plan-view specimens for transmission electron microscopy studies. The technique is simple, site-specific and is capable of fabricating multiple large, >100 ÎŒm2 electron transparent windows within epitaxially-grown thin films. A film of La0.67Sr0.33MnO3 is used to demonstrate the technique and its structural and functional properties are surveyed by high resolution imaging, electron spectroscopy, atomic force microscopy and Lorentz electron microscopy. The window is demonstrated to have good thickness uniformity and a low defect density that does not impair the filmâs Curie temperature. The technique will enable the study of inâplane structural and functional properties of a variety of epitaxial thin film systems
Quantum walk on distinguishable non-interacting many-particles and indistinguishable two-particle
We present an investigation of many-particle quantum walks in systems of
non-interacting distinguishable particles. Along with a redistribution of the
many-particle density profile we show that the collective evolution of the
many-particle system resembles the single-particle quantum walk evolution when
the number of steps is greater than the number of particles in the system. For
non-uniform initial states we show that the quantum walks can be effectively
used to separate the basis states of the particle in position space and
grouping like state together. We also discuss a two-particle quantum walk on a
two- dimensional lattice and demonstrate an evolution leading to the
localization of both particles at the center of the lattice. Finally we discuss
the outcome of a quantum walk of two indistinguishable particles interacting at
some point during the evolution.Comment: 8 pages, 7 figures, To appear in special issue: "quantum walks" to be
published in Quantum Information Processin
Thin-film cryogenic accelerator targets
Thin-film accelerator targets (0.1 mg/cm2 x 2) produced by condensation of various gases (Ar, Kr, Xe, N2, etc.) onto thin, cryogenically cooled substrates (T = 20 K to 80 K) have been developed and tested in-beam with 35 MeV 4He.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23775/1/0000013.pd
Outsourcing Governance: States and the Politics of a âGlobal Value Chain Worldâ
Politics, and by extension states, are marginal in debates about the genesis, evolution
and functioning of the GVC-based global economy. We contend here that the core complexity of
state agency and state power needs to be much more carefully understood in GVC and related
debates, as a basis on which the governance of the evolving GVC world can be properly
theorised as revolving around the inseparability of economic and political power. We advance a
framework for understanding the role of politics and states in the construction and maintenance
of a GVC world, using a three-fold typology of facilitative, regulatory and distributive forms of
governance, and propose a notion of âoutsourcing governanceâ as an attempt to capture the
ways in which states purposefully, through active political agency, have engaged in a process of
delegating a variety of governance functions and authority to private actors. Our overarching
argument is normative: âoutsourced governanceâ of the form we currently observe is associated
with regressive distributional outcomes, and is antithetical to an inclusive and sustainable global
economy
Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab
We present measurements of the differential cross section and Lambda recoil
polarization for the gamma p to K+ Lambda reaction made using the CLAS detector
at Jefferson Lab. These measurements cover the center-of-mass energy range from
1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles.
Independent analyses were performed using the K+ p pi- and K+ p (missing pi -)
final-state topologies; results from these analyses were found to exhibit good
agreement. These differential cross section measurements show excellent
agreement with previous CLAS and LEPS results and offer increased precision and
a 300 MeV increase in energy coverage. The recoil polarization data agree well
with previous results and offer a large increase in precision and a 500 MeV
extension in energy range. The increased center-of-mass energy range that these
data represent will allow for independent study of non-resonant K+ Lambda
photoproduction mechanisms at all production angles.Comment: 22 pages, 16 figure
Tensor Correlations Measured in 3He(e,e'pp)n
We have measured the 3He(e,e'pp)n reaction at an incident energy of 4.7 GeV
over a wide kinematic range. We identified spectator correlated pp and pn
nucleon pairs using kinematic cuts and measured their relative and total
momentum distributions. This is the first measurement of the ratio of pp to pn
pairs as a function of pair total momentum, . For pair relative
momenta between 0.3 and 0.5 GeV/c, the ratio is very small at low and
rises to approximately 0.5 at large . This shows the dominance of
tensor over central correlations at this relative momentum.Comment: 4 pages, 4 figures, submitted to PR
Bacterial diversity in snow from mid-latitude mountain areas: Alps, Eastern Anatolia, Karakoram and Himalaya
Snow can be considered an independent ecosystem that hosts active microbial communities. Snow microbial communities have been extensively investigated in the Arctic and in the Antarctica, but rarely in mid-latitude mountain areas. In this study, we investigated the bacterial communities of snow collected in four glacierized areas (Alps, Eastern Anatolia, Karakoram and Himalaya) by high-throughput DNA sequencing. We also investigated the origin of the air masses that produced the sampled snowfalls by reconstructing back-trajectories. A standardized approach was applied to all the analyses in order to ease comparison among different communities and geographical areas. The bacterial communities hosted from 25 to 211 Operational Taxonomic Units (OTUs), and their structure differed significantly between geographical areas. This suggests that snow bacterial communities may largely derive from 'local' air bacteria, maybe by deposition of airborne particulate of local origin that occurs during snowfall. However, some evidences suggest that a contribution of bacteria collected during air mass uplift to snow communities cannot be excluded, particularly when the air mass that originated the snow event is particularly rich in dust
Internalized HIV Stigma Predicts Suboptimal Retention in Care among People Living with HIV in the United States
HIV-related stigma is a known barrier to retention in care. However, no large-scale, multi-site studies have prospectively evaluated the effect of internalized stigma on retention in care. The Centers for AIDS Research Network of Integrated Clinical Systems (CNICS) cohort study integrates medical record and survey data from people living with HIV (PLWH) seen in HIV primary care clinics across the United States, and assesses internalized stigma yearly using a validated 4-item Likert scale. We used multivariable logistic regression models to evaluate associations between mean internalized stigma and two prospective retention in care outcomes: keeping the next primary care appointment and keeping all scheduled primary care appointments in the 12 months following stigma assessment. From February 2016 to November 2017, 5968 PLWH completed the stigma assessment and had adequate follow-up time. Mean stigma was 1.9 (standard deviation 1.08). Increased mean stigma scores were associated with decreased odds of attending the next primary care appointment [adjusted odds ratio (aOR) = 0.93, 95% confidence interval (CI) 0.88-0.99, p = 0.02], and all primary care appointments in the subsequent 12 months (aOR = 0.94, 95% CI 0.89-0.99, p = 0.02). In both models, younger age and Black race were also independently associated with suboptimal appointment attendance. There was no support for interactions between internalized stigma and covariates. Internalized HIV stigma had an independent negative effect on the odds of subsequent appointment attendance. This study highlights the importance of identifying even low levels of internalized stigma. Interventions to address internalized HIV stigma are critical to supporting retention in care and improving clinical outcomes
Measurement of the nuclear multiplicity ratio for hadronization at CLAS
The influence of cold nuclear matter on lepto-production of hadrons in
semi-inclusive deep inelastic scattering is measured using the CLAS detector in
Hall B at Jefferson Lab and a 5.014 GeV electron beam. We report the
multiplicity ratios for targets of C, Fe, and Pb relative to deuterium as a
function of the fractional virtual photon energy transferred to the
and the transverse momentum squared of the . We find that the
multiplicity ratios for are reduced in the nuclear medium at high
and low , with a trend for the transverse momentum to be
broadened in the nucleus for large .Comment: Submitted to Phys. Lett.
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