Development of Heterogeneous Photosensitized Transition Metal Oxide Water-Splitting Catalysts on Silica Support

The research presented in this manuscript describes the development of photosensitized inexpensive catalysts based on readily available materials. The investigation covers synthesis and characterization of photosensitizers based on porphyrins, mechanical and thermal coating of solid support with semiconducting transition metal oxides, photosensitization of the semiconducting layer, and characterization of the photoelectrochemical properties displayed by the new materials. The process of water oxidation is of primary interest here, with little emphasis put on reduction of protons to gaseous hydrogen. Photoelectrochemically produced protons serve as a probe of effectiveness of the catalysts. Several systems are described, and two catalysts are identified as the most efficient

Late Holocene Pollen Stratigraphy in Four Northeastern United States Lakes

Four pollen diagrams from Maine, New York, and Pennsylvania provide fine resolution (40 or 80 years) records of vegetation change in northeastern United States during the past 2000 years. A long term increase in pollen accumulation rates (PAR) of Picea occurred at the three sites in Maine and New York. Around 1100 years ago, Tsuga and Fagus decreased and Quercus and Castanea increased at Ely Lake in northeastern Pennsylvania. Around 500 years ago, Tsuga and Fagus greatly decreased in Maine and northern New York, while in northeastern Pennsylvania there was an increase in Tsuga and Fagus and a decrease in Quercus and Castanea pollen. Non-arboreal PAR were negligible prior to the European settlement of the area, after which there was an abrupt increase in non-arboreal pollen types.Quatre diagrammes polliniques des états du Maine, de New York et de Pennsylvanie illustrent de manière détaillée (40 ou 80 ans) les changements survenus dans la végétation du nord-est des États-Unis sur une période de 2000 ans. Les trois diagrammes des états du Maine et de New York enregistrent un accroissement continu de l'influx pollinique (PAR) de Picea. Il y a environ 1100 ans, Tsuga et Fagus ont subi une diminution, tandis que Quercus et Castanea ont augmenté à Ely Lake, dans le nord-est de la Pennsylvanie. Il y a 500 ans, Tsuga et Fagus ont considérablement diminué dans les états du Maine et de New York, alors que leur représentation pollinique augmentait dans le nord-est de la Pennsylvanie et que Quercus et Castanea diminuaient. Les influx polliniques des herbacés étaient minimes avant l'arrivée des Européens dans la région, après quoi ces taxons ont connu une augmentation subite.Vier Pollen-Diagramme von Maine, New York und Pennsylvania geben detaillierte Auflôsungs-Nachweise der Vegetationswechsel im Nordosten der Vereinigten Staaten wàhrend der letzten 2000 Jahre. Ein langfristiges Anwachsen der Pollen-Akkumulationsraten (PAR) von Picea trat an den drei Fundstellen in Maine und im Staat New York auf. Vor ungefàhr 11000 Jahren, nahmen am Ely-See in Nordost-Pennsylvania Tsuga and Fagus ab und Quercus und Castanea zu. Vor ungefàhr 500 Jahren nahmen in Maine und im Norden des staats New York Tsuga und Fagus stark ab, wàhrend in Nordost-Pennsylvania Tsuga und Fagus zunahmen und Quercus und Casfanea-Pollen abnahmen. Die nicht von Bàumen stammenden PAR waren gering, bevor das Gebiet von Europàern besiedelt wurde, wàhrend danach die nicht von Bàumen stammenden Pollenarten plôtzlich anwuchsen

31P-NMR and muSR Studies of Filled Skutterudite Compound SmFe4P12: Evidence for Heavy Fermion Behavior with Ferromagnetic Ground State

The 31P-NMR (nuclear magnetic resonance) and muSR (muon spin relaxation) measurements on the filled skutterudite system SmFe4P12 have been carried out. The temperature T dependence of the 31P-NMR spectra indicates the existence of the crystalline electric field effect splitting of the Sm3+$ (J = 5/2) multiplet into a ground state and an excited state of about 70 K. The spin-lattice relaxation rate 1/T1 shows the typical behavior of the Kondo system, i.e., 1/T1 is nearly T independent above 30 K, and varies in proportion to T (the Korringa behavior, 1/T1 \propto T) between 7.5 K and 30 K. The T dependence deviated from the Korringa behavior below 7 K, which is independent of T in the applied magnetic field of 1 kOe, and suppressed strongly in higher fields. The behavior is explained as 1/T1is determined by ferromagnetic fluctuations of the uncovered Sm3+ magnetic moments by conduction electrons. The muSR measurements in zero field show the appearance of a static internal field associated with the ferromagnetic order below 1.6 K.Comment: 6 pages, 9 figures, to be published in J. Phys. Soc. Jpn. 75 (2006

Longtime behavior of nonlocal Cahn-Hilliard equations

Here we consider the nonlocal Cahn-Hilliard equation with constant mobility in a bounded domain. We prove that the associated dynamical system has an exponential attractor, provided that the potential is regular. In order to do that a crucial step is showing the eventual boundedness of the order parameter uniformly with respect to the initial datum. This is obtained through an Alikakos-Moser type argument. We establish a similar result for the viscous nonlocal Cahn-Hilliard equation with singular (e.g., logarithmic) potential. In this case the validity of the so-called separation property is crucial. We also discuss the convergence of a solution to a single stationary state. The separation property in the nonviscous case is known to hold when the mobility degenerates at the pure phases in a proper way and the potential is of logarithmic type. Thus, the existence of an exponential attractor can be proven in this case as well

Composition and dynamics of high power impulse magnetron discharge at W-Mo-C target in argon atmosphere

Metal-doped diamond-like carbon (Me-DLC) is a typical industrial solution for wear resistant coating due to their tribological properties. DLC doping with metal is used to reduce internal stress of the DLC coating, improve its thermal stability, hardness, coating-substrate adhesion, and wear resistance. Furthermore, application of the High Power Impulse Magnetron Sputtering (HiPIMS) for Me-DLC deposition allows improvement of coating adhesion and densification of the coating. To improve the properties of the DLC coatings doping with tungsten and molybdenum from a mixed W-Mo-C target can be used. This study concerns the plasma chemistry and composition for a W-Mo-C target operated with HIPIMS in argon atmosphere. For a HIPIMS discharge with a fixed pulse length of 150 μs a linear dependence of the average power and current are observed. The optical emission spectroscopy experiments reveal a temporal dependence of the plasma composition as the current pulse develops. First plasma is dominated by argon neutrals and ions followed by molybdenum and tungsten. Significant separation between the two metal species is observed in terms of the times of onset and peak of the emission. As a consequence of the change of the neutral gas to metal ratio the estimated effective electron temperature, Te, changes from ~2 eV as estimated from Ar I emission to ~0.3-0.6 eV as indicated by W I emission. A change of Te is also observed with the change of HIPIMS frequency: the Te estimated from metal excitations increases most probably as a result of the processes taking place in the afterglow phase between HIPIMS pulses. The transition from argon plasma at the beginning of the pulse to metal-rich plasma in the second phase of the pulse is discussed in comparison with the ion current measurements performed with a planar probe

Comparison of dichotomized and distributional approaches in rare event clinical trial design: a fixed Bayesian design

Accepted 14 July 2016This research was motivated by our goal to design an efficient clinical trial to compare two doses of docosahexaenoic acid supplementation for reducing the rate of earliest preterm births (ePTB) and/or preterm births (PTB). Dichotomizing continuous gestational age (GA) data using a classic binomial distribution will result in a loss of information and reduced power. A distributional approach is an improved strategy to retain statistical power from the continuous distribution. However, appropriate distributions that fit the data properly, particularly in the tails, must be chosen, especially when the data are skewed. A recent study proposed a skew-normal method. We propose a three-component normal mixture model and introduce separate treatment effects at different components of GA. We evaluate operating characteristics of mixture model, beta-binomial model, and skew-normal model through simulation. We also apply these three methods to data from two completed clinical trials from the USA and Australia. Finite mixture models are shown to have favorable properties in PTB analysis but minimal benefit for ePTB analysis. Normal models on log-transformed data have the largest bias. Therefore we recommend finite mixture model for PTB study. Either finite mixture model or beta-binomial model is acceptable for ePTB study.Yang Lei, Susan Carlson, Lisa N. Yelland, Maria Makrides, Robert Gibson and Byron J. Gajewsk

C-axis Josephson Tunneling Between YBCO and Pb: Direct Evidence for Mixed Order Parameter Symmetry in a High-T_c Superconductor

We report a new class of $c$-axis Josephson tunneling experiments in which a conventional superconductor (Pb) is deposited across a single twin boundary of a YBa_2Cu_3O_{7-\delta} crystal. We measure the critical current as a function of magnitude and angle of magnetic field applied in the plane of the junction. In all samples, we observe a clear experimental signature of an order parameter phase shift across the twin boundary. These results provide strong evidence for mixed $d$- and $s$-wave pairing in YBCO, with a reversal in the sign of the $s$-wave component across the twin boundary.Comment: 4 pages RevTex, 4 postscript figures included, submitted to Phys. Rev. Let