2,978 research outputs found
Enhanced electrodeposition for the filling of micro-vias
This thesis investigated the introduction of megasound (MS) (1MHz) acoustic
technology as an enhanced agitation method of an electrolyte solution for the
electrochemical deposition of copper (Cu), used in electroplating processes. The thesis,
carried out at Merlin Circuit Technology Ltd, studied the possibility of improving
processing capabilities for use in Printed Circuit Board (PCB) industrial manufacture.
Prior laboratory experiments demonstrated increased metallisation of vertical
interconnect access (via) features in a Printed Circuit Board (PCB), which, if applied
within manufacturing, would enable increased connectivity throughout a PCB and result
in cost savings.
PCB manufacturing quality after MS-assisted Cu electroplating was assessed by
measurements of the topography of the electrodeposits, using scanning electron
microscopy and white-light interferometry. Cu plating rate changes were also measured
on the surface of the PCB and inside the vias.
After plating Cu with MS-assistance, the macro and microscale surface
composition was demonstrated to alter due to the direct influence of the acoustic waves.
Systematic characteristic of the surface was conducted by varying the settings of the
acoustic transducer device as well as the process parameters including electrical current
distribution, bath additive chemistry and solution temperature.
MS processing was shown to produce unique Cu artefacts. Their deleterious
formation was demonstrated to be influenced by acoustic standing waves and
microbubble formations at the electrolyte solution/PCB interface. Causes of these
artefacts, microfluidic streaming and cavitation, were also observed and controlled to
reduce the creation of these artefacts.
MS plating Cu down through-hole via (THV) and blind-via (BV) interconnects
was shown to produce measureable benefits. These include, for THVs, a 700 % increase
of Cu plating deposit thickness within a 175 ÎŒm diameter, depth-to-width aspect ratio (ar)
of 5.7:1, compared with processing under no-agitation conditions. For BVs, a 60 %
average increase in Cu deposition in 150 ÎŒm and 200 ÎŒm, ar 1:1, was demonstrated
against plating under standard manufacturing conditions - bubble agitation and panel
movement.Engineering and Physical Research Council (EPSRC) grant number EP/G037523/
The behaviour of political parties and MPs in the parliaments of the Weimar Republic
Copyright @ 2012 The Authors. This is the author's accepted manuscript. The final published article is available from the link below.Analysing the roll-call votes of the MPs of the Weimar Republic we find: (1) that party competition in the Weimar parliaments can be structured along two dimensions: an economic leftâright and a pro-/anti-democratic. Remarkably, this is stable throughout the entire lifespan of the Republic and not just in the later years and despite the varying content of votes across the lifespan of the Republic, and (2) that nearly all parties were troubled by intra-party divisions, though, in particular, the national socialists and communists became homogeneous in the final years of the Republic.Zukunftskolleg, University of Konstan
Direct determination of mode-projected electron-phonon coupling in the time-domain
Ultrafast spectroscopies have become an important tool for elucidating the
microscopic description and dynamical properties of quantum materials. In
particular, by tracking the dynamics of non-thermal electrons, a material's
dominant scattering processes -- and thus the many-body interactions between
electrons and collective excitations -- can be revealed. Here we present a new
method for extracting the electron-phonon coupling strength in the time domain,
by means of time and angle-resolved photoemission spectroscopy (TR-ARPES). This
method is demonstrated in graphite, where we investigate the dynamics of
photo-injected electrons at the K point, detecting quantized energy-loss
processes that correspond to the emission of strongly-coupled optical phonons.
We show that the observed characteristic timescale for spectral-weight-transfer
mediated by phonon-scattering processes allows for the direct quantitative
extraction of electron-phonon matrix elements, for specific modes, and with
unprecedented sensitivity.Comment: 19 pages, 4 figure
Prevalence of intestinal microsporidiosis in Human Immunodeficiency Virus-infected patients with diarrhea in major United States cities
To determine the prevalence of intestinal microsporidiosis in HIV-infected patients, we performed a prospective study of HIV-infected patients with diarrheal illnesses in three US hospitals and examined an observational database of HIV-infected patients in 10 US cities. Among 737 specimens from the three hospitals, results were positive for 11 (prevalence 1.5%); seven (64%) acquired HIV through male-to-male sexual contact, two (18%) through male-to-male sexual contact and injection drug use, and one (9%) through heterosexual contact; one (9%) had an undetermined mode of transmission. Median CD4 count within six months of diagnosis of microsporidiosis was 33 cells/”L (range 3 to 319 cells/”L). For the national observational database (n = 24,098), the overall prevalence of microsporidiosis was 0.16%. Prevalence of microsporidiosis among HIV-infected patients with diarrheal disease is low, and microsporidiosis is most often diagnosed in patients with very low CD4+ cell counts. Testing for microsporidia appears to be indicated, especially for patients with very low CD4+ cell counts.Para determinar a prevalĂȘncia de microsporidiose intestinal em pacientes infectados pelo HIV foi realizado um estudo prospectivo em trĂȘs hospitais dos Estados Unidos da AmĂ©rica do Norte (EUA) e analizada uma base de dados nacional composta de dados coletados de pacientes infectados pelo HIV em 10 cidades dos EUA. De um total de 737 amostras de fezes de pacientes infectados pelo HIV que apresentavam diarrĂ©ia, amostras de 11 pacientes (prevalĂȘncia de 1,5%) foram positivas para microsporĂdios. Todos os positivos eram do sexo masculino e, entre eles, sete (64%) pacientes adquiriram a infecção pelo HIV atravĂ©s de relação homossexual, dois (18%) atravĂ©s de relação sexual e drogas injetĂĄveis e um (9%) atravĂ©s de contato heterosexual, enquanto que em um paciente o modo de transmissĂŁo do HIV nĂŁo foi determinado. A contagem mĂ©dia de linfĂłcitos CD4 realizada atĂ© seis meses do diagnĂłstico de microsporidiose foi de 33 cĂ©lulas/microlitro (3 a 319 cĂ©lulas/microlitro). A anĂĄlise da base de dados nacional (n = 24.098) mostrou uma prevalĂȘncia de microsporidiose de 0,16%. A prevalĂȘncia de microsporidiose em pacientes HIV-positivos com diarrĂ©ia Ă© baixa. Entretando, como a microsporidiose Ă© mais frequentemente diagnosticada em pacientes com contagens de CD4 muito baixas, a indicação de pesquisa de microsporĂdios Ă© justificada, especialmente para estes pacientes
Hypoaminoacidemia underpins glucagon-mediated energy expenditure and weight loss
Glucagon analogs show promise as components of next-generation, multi-target, anti-obesity therapeutics. The biology of chronic glucagon treatment, in particular, its ability to induce energy expenditure and weight loss, remains poorly understood. Using a long-acting glucagon analog, G108, we demonstrate that glucagon-mediated body weight loss is intrinsically linked to the hypoaminoacidemia associated with its known amino acid catabolic action. Mechanistic studies reveal an energy-consuming response to low plasma amino acids in G108-treated mice, prevented by dietary amino acid supplementation and mimicked by a rationally designed low amino acid diet. Therefore, low plasma amino acids are a pre-requisite for G108-mediated energy expenditure and weight loss. However, preventing hypoaminoacidemia with additional dietary protein does not affect the ability of G108 to improve glycemia or hepatic steatosis in obese mice. These studies provide a mechanism for glucagon-mediated weight loss and confirm the hepatic glucagon receptor as an attractive molecular target for metabolic disease therapeutics
The Atacama Cosmology Telescope: Cosmology from Galaxy Clusters Detected via the Sunyaev-Zel'dovich Effect
We present constraints on cosmological parameters based on a sample of
Sunyaev-Zel'dovich-selected galaxy clusters detected in a millimeter-wave
survey by the Atacama Cosmology Telescope. The cluster sample used in this
analysis consists of 9 optically-confirmed high-mass clusters comprising the
high-significance end of the total cluster sample identified in 455 square
degrees of sky surveyed during 2008 at 148 GHz. We focus on the most massive
systems to reduce the degeneracy between unknown cluster astrophysics and
cosmology derived from SZ surveys. We describe the scaling relation between
cluster mass and SZ signal with a 4-parameter fit. Marginalizing over the
values of the parameters in this fit with conservative priors gives sigma_8 =
0.851 +/- 0.115 and w = -1.14 +/- 0.35 for a spatially-flat wCDM cosmological
model with WMAP 7-year priors on cosmological parameters. This gives a modest
improvement in statistical uncertainty over WMAP 7-year constraints alone.
Fixing the scaling relation between cluster mass and SZ signal to a fiducial
relation obtained from numerical simulations and calibrated by X-ray
observations, we find sigma_8 = 0.821 +/- 0.044 and w = -1.05 +/- 0.20. These
results are consistent with constraints from WMAP 7 plus baryon acoustic
oscillations plus type Ia supernoava which give sigma_8 = 0.802 +/- 0.038 and w
= -0.98 +/- 0.053. A stacking analysis of the clusters in this sample compared
to clusters simulated assuming the fiducial model also shows good agreement.
These results suggest that, given the sample of clusters used here, both the
astrophysics of massive clusters and the cosmological parameters derived from
them are broadly consistent with current models.Comment: 12 pages, 7 figures. Submitted to Ap
P1â349: Advancing Clinical And Biomarker Research In Ad: The Lead Study
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152716/1/alzjjalz201906904.pd
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
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