Etch free graphene transfer to polymers Lock, E.H.; Hernández, S.C.; Anderson, T.J. ...
Surface & coatings technology,
02/2014, Letnik:
241
Journal Article, Conference Proceeding
Recenzirano
Graphene transfer is critical for successful graphene-device integration. Even though multiple transfer approaches have been developed, an optimal solution is still not available. In this paper, we ...demonstrate dry transfer of graphene transfer Cu foil to polystyrene using mild heat and pressure. Two different printing systems are evaluated: a wafer bonder and a more cost-effective heat press. Chemical, morphological, structural and electrical characterization of the samples before and after transfer is performed. The results suggest that differences in the operation of the printing devices can be correlated to uniformity of transferred graphene. Regardless of the printing approach the surface resistivity of the polymer was decreased by 16 orders of magnitude.
•Graphene etch-free transfer was achieved at atmospheric pressure under mild force.•Force (pressure) requirements depend on the press system.•Graphene/polymer surface conductivity was increased by 16 orders of magnitude.•Graphene transfer depends on molecular bonding and polymer/Cu foil conformality.•The developed approach reduces the overall cost of graphene transfer process.
This experiment investigated the effect of two nutritional levels (medium and ad libitum) from day 85 of pregnancy until parturition on the live weight and metabolic status of twin-bearing hoggets, ...and the gamma-glutamyl transferase and glucose concentration on the day of lambing (L1), survival and live weight of their offspring until L29. The mean live weight of the ad libitum treatment hoggets (66.3±0.6 kg) was greater (P<0.05) at P145 than that of medium treatment hoggets (63.6±0.5 kg). Hogget live weight did not differ (P>0.05) between treatments at L29 (60.9±0.9 vs 60.0±1.0 kg for the medium and ad libitum treatment hoggets, respectively). The birth weight of lambs born to ad libitum ewes (4.0±0.1 kg) was greater (P<0.05) than that of lambs born to medium treatment ewes (3.7±0.1 kg). At L29, lamb live weight did not differ (P>0.05) between treatments (11.2±0.3 vs 11.3±0.3 for the medium and ad libitum treatments, respectively). Lamb survival did not differ (P>0.05) between treatments. There was no difference between treatments in the efficiency of lamb live weight produced. These results indicate that offering twin-bearing hoggets ad libitum levels of herbage from day 85 of pregnancy until parturition is not an efficient technique to increase lamb production from these hoggets. Farmers should, therefore, offer 1000–1400 kg DM/ha to optimize lamb production from twin-bearing hoggets.
Two experiments were conducted to compare the reproductive performance of ewe hoggets and mature ewes. All ewes were synchronized by an intravaginal progesterone-releasing device and bred together ...over a 5-day period. In Experiment 1, of those joined with the ram, more mature ewes ovulated (99% vs 68%; P < 0.05) with a higher ovulation rate (1.82 vs 1.14; P < 0.05) than ewe hoggets. Mature ewes had a higher pregnancy rate (98% vs 47%; P < 0.05) and lower early pregnancy loss (13% vs 41%; P < 0.05) than ewe hoggets. In Experiment 2, the ovulation rate (1.84 vs 1.44; P < 0.05) and pregnancy rate (86% vs 7%; P < 0.05) was higher in mature ewes compared with ewe hoggets. Combined, these studies help to quantify the difference in reproductive performance during breeding and pregnancy between ewe hoggets and mature ewes, and help to direct further research.
Volcanic eruptions contribute to climate variability, but quantifying these contributions has been limited by inconsistencies in the timing of atmospheric volcanic aerosol loading determined from ice ...cores and subsequent cooling from climate proxies such as tree rings. Here we resolve these inconsistencies and show that large eruptions in the tropics and high latitudes were primary drivers of interannual-to-decadal temperature variability in the Northern Hemisphere during the past 2,500 years. Our results are based on new records of atmospheric aerosol loading developed from high-resolution, multi-parameter measurements from an array of Greenland and Antarctic ice cores as well as distinctive age markers to constrain chronologies. Overall, cooling was proportional to the magnitude of volcanic forcing and persisted for up to ten years after some of the largest eruptive episodes. Our revised timescale more firmly implicates volcanic eruptions as catalysts in the major sixth-century pandemics, famines, and socioeconomic disruptions in Eurasia and Mesoamerica while allowing multi-millennium quantification of climate response to volcanic forcing.
This work compared the reproductive performance of ewe lambs and mature ewes and the growth of their lambs from birth to weaning under conditions in which they had been managed as a single group. Two ...studies were conducted; the first study, conducted in 2007, included 307 multiparous mature ewes and 297 primiparous ewe lambs and the second study, conducted in 2009, included 399 multiparous mature ewes and 400 primiparous ewe lambs. Physical measures of ewes and lambs were recorded as was their behaviour within 12h of birth in study one. Ewe lambs were lighter (P<0.05) than mature ewes throughout pregnancy and lactation. However, the total live weight gained during pregnancy was similar (P>0.05). Lambs born to ewe lambs were smaller (P<0.05) and lighter (P<0.05) than their birth rank contemporaries born to mature ewes. However, single lambs born to ewe lambs and twin lambs born to mature ewes had similar birth weights and growth to weaning. Lamb survival rates were lowest (P<0.05) for lambs born to ewe lambs although in study two, singleton lambs born to ewe lambs had similar survival rates to both singleton and twin lambs born to mature ewes. This study identified that the limitations to ewe lamb breeding were that they produced smaller, lighter lambs with lower survival rates to weaning and maternal behaviour indicating a lack of experience compared to mature ewes. Therefore future research should be directed at alleviating these constraints.
We describe a geophysical technique to measure englacial vertical velocities through to the beds of ice sheets without the need for borehole drilling. Using a ground‐based phase‐sensitive radio echo ...sounder (pRES) during seven Antarctic field seasons, we measure the temporal changes in the position of englacial reflectors within ice divides up to 900 m thick on Berkner Island, Roosevelt Island, Fletcher Promontory, and Adelaide Island. Recorded changes in reflector positions yield “full‐depth” profiles of vertical ice velocity that we use to examine spatial variations in ice flow near the divides. We interpret these variations by comparing them to the results of a full‐Stokes simulation of ice divide flow, qualitatively validating the model and demonstrating that we are directly detecting an ice‐dynamical phenomenon called the Raymond Effect. Using pRES, englacial vertical ice velocities can be measured in higher spatial resolution than is possible using instruments installed within the ice. We discuss how these measurements could be used with inverse methods to measure ice rheology and to improve ice core dating by incorporating pRES‐measured vertical velocities into age modeling.
Key Points
Phase‐sensitive radar measures vertical ice velocities within ice dividesTheoretical predictions of ice flow patterns around ice divide are confirmedResults provide strong evidence that power law ice rheologies are incomplete
Ground‐based surveys of ice‐divide triple junctions in two Antarctic ice rises, the Fletcher Promontory and Berkner Island, have been carried out using low‐frequency ice‐penetrating radars. These ...surveys have focused on understanding the internal layer architecture at and around the triple junctions, with a particular emphasis on understanding how the Raymond effect operates. A variety of features have been observed, including Raymond cupolas under the junctions, bump stacks of varying amplitude with distance from the divide, double bumps, crooked stacks implying divide motion, and the presence of ridges containing weak and strong bump stacks. It was generally not possible to elucidate the three‐dimensional structure by correlation of pick crossovers, so instead a least squares cross‐correlation technique was used which computes nominal age surfaces using radial basis function interpolation. Double bumps are absent from the central cupola of Fletcher Promontory, permitting us to infer that the ice here has thinned by around 500 m in the past 5000 years. Estimates of the age scale suggest that there will be recoverable Eemian ice. A technique for inferring the velocity profile at divides using layer traces and assumed velocities in the flanks is presented.
Key Points
Radar surveys of ice divide domes
Processing method to create 3‐D structure
Timescale and thinning history of Fletcher Promontory
An idealised model of core-out in water assisted injection moulding (WAIM) is set up to isolate the effect of cooling by the water on the deposited layer thickness. Based on simulations, this is ...investigated for a specific case as a function of Pearson number and power law index. It is found that cooling significantly reduces the layer thickness to the extent that a change in the flow regime ahead of the bubble, from bypass to recirculating flow, is possible. For shear thinning melts with high temperature coefficient of viscosity, the simulations show very low layer thickness, which may indicate unfavourable conditions for WAIM. Although in the real moulding situation, other effects will be superimposed on those found here, the results provide new insights into the fundamentals of WAIM. Investigation of other effects characterised by Fourier and Reynolds numbers will be reported subsequently. Some early process measurement results from an experimental WAIM mould are presented. Reductions in residual wall thickness are observed as the water injection set pressure is increased and the duration of water bubble penetration through the melt is determined experimentally. The formation of voids within the residual wall is noted and observed to reduce in severity with increasing water injection pressure. The presence of such voids can be detected by the signature from an infrared temperatures sensor.
In order to evaluate further the efficacy of local intramuscular injections of botulinum-A toxin (BAT-A) in the management of dynamic equinus deformity associated with cerebral palsy, a randomized, ...double-blind, placebo-controlled study was undertaken. When evaluated using our Physician Rating Scale, 83% (five of six) of patients receiving toxin showed improvement, versus 33% (two of six) receiving placebo. There were no major complications. BAT-A injections appear to be safe and effective in children, and merit further prospective study.
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