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21.
Tyler R. Harrison Susan E. Morgan Lisa V. Chewning Elizabeth A. Williams Joshua B. Barbour Mark J. Di Corcia LaShara A. Davis 《The Journal of communication》2011,61(3):535-555
This article advances the beginnings of a general theory of organizational features to aid in understanding why health campaigns that work well in one organization may be ineffectual in another organization. The physical, social, and information structures of organizations are theorized to create an interaction environment that is distinct to each organization and that influences health campaigns. To test this argument, an organ donation campaign was conducted in 46 organizations. Multilevel modeling yielded mixed findings. Physical structure was negatively associated with signing an organ donor card. Social structure and information structure were positively associated with communication with coworkers about donation and communicative peer influence. Industry type was positively associated with knowledge change. 相似文献
22.
23.
Extreme Two‐Phase Cooling from Laser‐Etched Diamond and Conformal,Template‐Fabricated Microporous Copper 下载免费PDF全文
James W. Palko Hyoungsoon Lee Chi Zhang Tom J. Dusseault Tanmoy Maitra Yoonjin Won Damena D. Agonafer Jess Moss Farzad Houshmand Guoguang Rong Joshua D. Wilbur Derrick Rockosi Ihor Mykyta Dan Resler David Altman Mehdi Asheghi Juan G. Santiago Kenneth E. Goodson 《Advanced functional materials》2017,27(45)
This paper reports the first integration of laser‐etched polycrystalline diamond microchannels with template‐fabricated microporous copper for extreme convective boiling in a composite heat sink for power electronics and energy conversion. Diamond offers the highest thermal conductivity near room temperature, and enables aggressive heat spreading along triangular channel walls with 1:1 aspect ratio. Conformally coated porous copper with thickness 25 µm and 5 µm pore size optimizes fluid and heat transport for convective boiling within the diamond channels. Data reported here include 1280 W cm?2 of heat removal from 0.7 cm2 surface area with temperature rise beyond fluid saturation less than 21 K, corresponding to 6.3 × 105 W m?2 K?1. This heat sink has the potential to dissipate much larger localized heat loads with small temperature nonuniformity (5 kW cm?2 over 200 µm × 200 µm with <3 K temperature difference). A microfluidic manifold assures uniform distribution of liquid over the heat sink surface with negligible pumping power requirements (e.g., <1.4 × 10?4 of the thermal power dissipated). This breakthrough integration of functional materials and the resulting experimental data set a very high bar for microfluidic heat removal. 相似文献
24.
Bogdan Georgescu Joshua Nakaska Ivars Finvers Fadhel Ghannouchi 《Circuits, Systems, and Signal Processing》2012,31(5):1577-1597
The special LNA topologies resulting from loading a simple LNA with a set of Q-enhanced inductors are analyzed and compared. The Q of the on-chip spiral inductors that form the LNA load is enhanced by using a negative resistance realized with a cross-coupled differential pair degenerated and biased in various ways. The performance of the LNA is presented for the following types of Q-enhancement circuit: ideal negative resistor (ideal cell), tail-biased non-degenerated cross-coupled differential pair (classic cell), tail-biased resistively degenerated cross-coupled differential pair (resistive cell), tail-biased LC degenerated cross-coupled differential pair (B-cell), self-biased LC degenerated cross-coupled differential pair (BB-cell). The analysis focuses on the benefits of each cell related to s-parameter response, noise and linearity and the interdependency of Q vs. center frequency during tuning. Low voltage design challenges are addressed by presenting the advantages of the novel self-biased LC degenerated cross-coupled differential pair (BB-cell). 相似文献
25.
We introduce a probabilistic computer vision technique to track monotonically advancing boundaries of objects within image sequences. Our method incorporates a novel technique for including statistical prior shape information into graph-cut based segmentation, with the aid of a majorization-minimization algorithm. Extension of segmentation from single images to image sequences then follows naturally using sequential Bayesian estimation. Our methodology is applied to two unrelated sets of real biomedical imaging data, and a set of synthetic images. Our results are shown to be superior to manual segmentation. 相似文献
26.
Systematic Doping Control of CVD Graphene Transistors with Functionalized Aromatic Self‐Assembled Monolayers 下载免费PDF全文
Nathan Cernetic Sanfeng Wu Joshua A. Davies Benjamin W. Krueger Daniel O. Hutchins Xiaodong Xu Hong Ma Alex K.‐Y. Jen 《Advanced functional materials》2014,24(22):3464-3470
Recent reports have shown that self‐assembled monolayers (SAMs) can induce doping effects in graphene transistors. However, a lack of understanding persists surrounding the quantitative relationship between SAM molecular design and its effects on graphene. In order to facilitate the fabrication of next‐generation graphene‐based devices it is important to reliably and predictably control the properties of graphene without negatively impacting its intrinsic high performance. In this study, SAMs with varying dipole magnitudes/directions are utilized and these values are directly correlated to changes in performance seen in graphene transistors. It is found that, by knowing the z‐component of the SAM dipole, one can reliably predict the shift in graphene charge neutrality point after taking into account the influence of the metal electrodes (which also play a role in doping graphene). This relationship is verified through density functional theory and comprehensive device studies utilizing atomic force microscopy, X‐ray photoelectron spectroscopy, Raman spectroscopy, and electrical characterization of graphene transistors. It is shown that properties of graphene transistors can be predictably controlled with SAMs when considering the total doping environment. Additionally, it is found that methylthio‐terminated SAMs strongly interact with graphene allowing for a cleaner graphene transfer and enhanced charge mobility. 相似文献
27.
Functionalized Natural Particles: Light‐Induced Surface Modification of Natural Plant Microparticles: Toward Colloidal Science and Cellular Adhesion Applications (Adv. Funct. Mater. 18/2018) 下载免费PDF全文
28.
The computation of outage probability in cellular radio system has been extensively studied. The Signal-to-Interference-plus-Noise
Ratio (SINR) distribution involves the sum of lognormal distributions due to dominant effect of shadowing in both the signal
and interference components. Since no closed-form expression can be found for the sum of lognormal distributions, many approximation
methods and bounds were proposed in the past. In this paper, Log Shifted Gamma (LSG) approximation is proposed to calculate
the sum of correlated lognormal random variables (RVs), hence the outage probability, accurately with a wide range of dB spreads,
number of interferers M, correlation coefficients r among interference components, and noise power N. Overall, LSG approximation
shows consistent accuracy due to its flexibility over the classical lognormal approximation, especially with small correlation
coefficients r and/or large dB spreads. 相似文献
29.
Joshua D. Caldwell Orest J. Glembocki Robert E. Stahlbush Karl D. Hobart 《Journal of Electronic Materials》2008,37(5):699-705
While Shockley stacking fault (SSF) creation and expansion within 4H-SiC bipolar devices is well known, only recently was
it observed that this expansion and the associated increase in the forward voltage drop (V
f) could be completely reversed via low-temperature annealing. Here we report the temperature dependence of the recovery rate
of the V
f drift via annealing, reporting an activation energy of 1.3 ± 0.3 eV. The V
f drift was observed to saturate following extended electrical stressing, and it was observed that the value of V
f at this saturation was inversely proportional to the stressing temperature. We also observed that SSF and V
f drift recovery could occur in highly stressed diodes at elevated temperatures even under high current injection conditions
(14 A/cm2). 相似文献
30.
Recent advances in oxygen reduction reaction catalysis for proton exchange membrane fuel cells (PEMFCs) include i) the use of electrochemical dealloying to produce high surface area and sometimes nanoporous catalysts with a Pt‐enriched outer surface, and ii) the observation that oxygen reduction in nanoporous materials can be potentially enhanced by confinement effects, particularly if the chemical environment within the pores can bias the reaction toward completion. Here, these advances are combined by incorporating a hydrophobic, protic ionic liquid, [MTBD][beti], into the pores of high surface‐area NiPt alloy nanoporous nanoparticles (np‐NiPt/C + [MTBD][beti]). The high O2 solubility of the [MTBD][beti], in conjunction with the confined environment within the pores, biases reactant O2 toward the catalytic surface, consistent with an increased residence time and enhanced attempt frequencies, resulting in improved reaction kinetics. Half‐cell measurements show the np‐NiPt/C+[MTBD][beti] encapsulated catalyst to be nearly an order of magnitude more active than commercial Pt/C, a result that is directly translated into operational PEMFCs. 相似文献