2-D Electronic Materials: Epitaxial Growth Of Graphene On 6H-Silicon Carbide (0001)

Graphene holds great promise as a material for high-speed electronics, especially as Si technology approaches its performance limits. Growth of epitaxial graphene by thermal decomposition of SiC is considered to be one of the most promising production routes since it has the potential to produce homogenous, wafer-size films directly on a semi-insulating or semiconducting substrate. Furthermore, graphene's planar 2-D structure enables devices and circuit designs with standard top-down lithography and processing techniques. However, the growth mechanism of graphene on SiC is not very well understood and much work remains to be done to improve the morphology, domain size and epitaxial quality of the grown graphene in order to take advantage of the unique properties of the material. This research work was aimed at using a modified CVD chamber in the Cornell University Wide-Bandgap-Semiconductor Laboratory to optimize the growth of epitaxial graphene by controlled decomposition of 6H-SiC(0001) in an argon mediated gas flow at near atmospheric pressure. Grown films were characterized using Raman spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and electrical measurements. Uniform large-area monolayer and few-layer epitaxial graphene were successfully grown on SiC terraces of up to 8 [MICRO SIGN]m wide, and with Hall mobilities of up to 840 cm2/V.s. The as-grown graphene was found to be intrinsically electron doped with sheet carrier density in the range of 3 - 9 x 1012 cm-2. However, certain growth features that tended to disrupt growth by uniform step flow decomposition were observed. These included deep rounded pits at higher temperatures, shallow triangular pits, arrow-like incursions across terraces, finger growths, residual SiC islands on terraces, nucleation of graphene at multiple defect points on terraces, and extra graphene layers at step edges. Further research is required to determine the mechanisms of formation of these features and to determine how they can be eliminated or reduced. For the first time SiC grown epitaxial graphene films, transferred from the substrate by a special process, was imaged in plan-view by TEM. The TEM images, along with selected-area electron diffraction, showed that a bilayer film had the AB Bernal stacking.

Priorities for Patient‐Centered Outcomes Research: The Views of Minority and Underserved Communities

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136533/1/hesr12505_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136533/2/hesr12505.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136533/3/hesr12505-sup-0001-AppendixSA1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136533/4/hesr12505-sup-0002-AppendixSA2.pd

Members of Minority and Underserved Communities Set Priorities for Health Research

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146820/1/milq12354.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146820/2/milq12354_am.pd

The Deflationary Theory of Ontological Dependence

When an entity ontologically depends on another entity, the former ‘presupposes’ or ‘requires’ the latter in some metaphysical sense. This paper defends a novel view, Dependence Deflationism, according to which ontological dependence is what I call an aggregative cluster concept: a concept which can be understood, but not fully analysed, as a ‘weighted total’ of constructive and modal relations. The view has several benefits: it accounts for clear cases of ontological dependence as well as the source of disagreement in controversial ones; it gives a nice story about the evidential relevance of modal, mereological and set-theoretic facts to ontological dependence; and it makes sense of debates over the relation's formal properties. One important upshot of the deflationary account is that questions of ontological dependence are generally less deep and less interesting than usually thought

'To take care of the patients': Qualitative analysis of Veterans Health Administration personnel experiences with a clinical informatics system

<p>Abstract</p> <p>Background</p> <p>The Veterans Health Administration (VA) has invested significant resources in designing and implementing a comprehensive electronic health record (EHR) that supports clinical priorities. EHRs in general have been difficult to implement, with unclear cost-effectiveness. We describe VA clinical personnel interactions with and evaluations of the EHR.</p> <p>Methods</p> <p>As part of an evaluation of a quality improvement initiative, we interviewed 72 VA clinicians and managers using a semi-structured interview format. We conducted a qualitative analysis of interview transcripts, examining themes relating to participants' interactions with and evaluations of the VA EHR.</p> <p>Results</p> <p>Participants described their perceptions of the positive and negative effects of the EHR on their clinical workflow. Although they appreciated the speed and ease of documentation that the EHR afforded, they were concerned about the time cost of using the technology and the technology's potential for detracting from interpersonal interactions.</p> <p>Conclusions</p> <p>VA personnel value EHRs' contributions to supporting communication, education, and documentation. However, participants are concerned about EHRs' potential interference with other important aspects of healthcare, such as time for clinical care and interpersonal communication with patients and colleagues. We propose that initial implementation of an EHR is one step in an iterative process of ongoing quality improvement.</p

Precision measurement of the top quark mass from dilepton events at CDF II

We report a measurement of the top quark mass, M_t, in the dilepton decay channel of $t\bar{t}\to b\ell'^{+}\nu_{\ell'}\bar{b}\ell^{-}\bar{\nu}_{\ell}$ using an integrated luminosity of 1.0 fb^{-1} of p\bar{p} collisions collected with the CDF II detector. We apply a method that convolutes a leading-order matrix element with detector resolution functions to form event-by-event likelihoods; we have enhanced the leading-order description to describe the effects of initial-state radiation. The joint likelihood is the product of the likelihoods from 78 candidate events in this sample, which yields a measurement of M_{t} = 164.5 \pm 3.9(\textrm{stat.}) \pm 3.9(\textrm{syst.}) \mathrm{GeV}/c^2, the most precise measurement of M_t in the dilepton channel.Comment: 7 pages, 2 figures, version includes changes made prior to publication by journa

Measurement of the Dipion Mass Spectrum in X(3872) -> J/Psi Pi+ Pi- Decays

We measure the dipion mass spectrum in X(3872)--> J/Psi Pi+ Pi- decays using 360 pb-1 of pbar-p collisions at 1.96 TeV collected with the CDF II detector. The spectrum is fit with predictions for odd C-parity (3S1, 1P1, and 3DJ) charmonia decaying to J/Psi Pi+ Pi-, as well as even C-parity states in which the pions are from Rho0 decay. The latter case also encompasses exotic interpretations, such as a D0-D*0Bar molecule. Only the 3S1 and J/Psi Rho hypotheses are compatible with our data. Since 3S1 is untenable on other grounds, decay via J/Psi Rho is favored, which implies C=+1 for the X(3872). Models for different J/Psi-Rho angular momenta L are considered. Flexibility in the models, especially the introduction of Rho-Omega interference, enable good descriptions of our data for both L=0 and 1.Comment: 7 pages, 4 figures -- Submitted to Phys. Rev. Let