Surface Dipoles and Work Functions of Alkylthiolates and Fluorinated Alkylthiolates on Au(111)

We study the dipole formation at the surface formed by -CH3 and -CF3 terminated shortchain alkyl-thiolate monolayers on Au(111). In particular, we monitor the change in work function upon chemisorption using density functional theory calculations. We separate the surface dipole into two contributions, resulting from the gold-adsorbate interaction and the intrinsic dipole of the adsorbate layer, respectively. The two contributions turn out to be approximately additive. Adsorbate dipoles are defined by calculating dipole densities of free-standing molecular monolayers. The gold-adsorbate interaction is to a good degree determined by the Au-S bond only. This bond is nearly apolar and its contribution to the surface dipole is relatively small. The surface dipole of the self-assembled monolayer is then dominated by the intrinsic dipole of the thiolate molecules. Alkyl-thiolates increase the work function of Au(111), whereas fluorinated alkyl-thiolates decrease it.Comment: 24 pages, 5 figures, 4 table

First-principles study of the interaction and charge transfer between graphene and metals

Measuring the transport of electrons through a graphene sheet necessarily involves contacting it with metal electrodes. We study the adsorption of graphene on metal substrates using first-principles calculations at the level of density functional theory. The bonding of graphene to Al, Ag, Cu, Au and Pt(111) surfaces is so weak that its unique "ultrarelativistic" electronic structure is preserved. The interaction does, however, lead to a charge transfer that shifts the Fermi level by up to 0.5 eV with respect to the conical points. The crossover from p-type to n-type doping occurs for a metal with a work function ~5.4 eV, a value much larger than the work function of free-standing graphene, 4.5 eV. We develop a simple analytical model that describes the Fermi level shift in graphene in terms of the metal substrate work function. Graphene interacts with and binds more strongly to Co, Ni, Pd and Ti. This chemisorption involves hybridization between graphene $p_z$-states and metal d-states that opens a band gap in graphene. The graphene work function is as a result reduced considerably. In a current-in-plane device geometry this should lead to n-type doping of graphene.Comment: 12 pages, 9 figure

Formal Model Engineering for Embedded Systems Using Real-Time Maude

This paper motivates why Real-Time Maude should be well suited to provide a formal semantics and formal analysis capabilities to modeling languages for embedded systems. One can then use the code generation facilities of the tools for the modeling languages to automatically synthesize Real-Time Maude verification models from design models, enabling a formal model engineering process that combines the convenience of modeling using an informal but intuitive modeling language with formal verification. We give a brief overview six fairly different modeling formalisms for which Real-Time Maude has provided the formal semantics and (possibly) formal analysis. These models include behavioral subsets of the avionics modeling standard AADL, Ptolemy II discrete-event models, two EMF-based timed model transformation systems, and a modeling language for handset software.Comment: In Proceedings AMMSE 2011, arXiv:1106.596

Magnetic Order in the 2D Heavy-Fermion System CePt2In7 studied by muSR

The low-temperature microscopic magnetic properties of the quasi-2D heavyfermion compound, CePt2In7 are investigated by using a positive muon-spin rotation and relaxation (?muSR) technique. Clear evidence for the formation of a commensurate antiferromagnetic order below TN=5.40 K is presented. The magnetic order parameter is shown to fit well to a modified BSC gap-energy function in a strong-coupling scenario.Comment: Accepted in Journal of Physics: Conference Series (2014

Актуальность профилактики тромбоэмболии легочной артерии в пред-, интра- и постоперационном периоде

Catedra Anesteziologie şi Reanimatologie nr. 2, USMF „Nicolae Testemiţanu”The purpose of this article is an informative analysis of the efficiency of prophylaxis of the pulmonary artery trombembolism. Out of 627 patients monitored, 473 had the benefit of a perioperatory tromboprophylaxis, while the other 154 patients got only a postoperatory tromboprophylaxis. The incidence of pulmonary artery trombembolism is 0.48%, this result refers only to patients operated on urgently. The incidence of lethal cases is 0.16%. Pulmonary artery trombembolism incidence varies depending on the combination of predisposing factors. We studied several combined methods of prophylaxis. Priority was the combination of mechanical methods (application of elastic bandages on the legs) with low molecular mass heparins. From observation of the study we determined an increased efficiency using the combination of mechanical methods with Enoxoparine (Klexan) in tromboprophylaxis of patients with moderate and high risk of pulmonary artery trombembolism. The priorities of Enoxoparine, to other low molecular weight heparins do not require the determination of bleeding and clotting time during administration. Also there was no change in platelet count in patients receiving Enoxoparine.Целью данной статьи является информативный анализ эффективности профилактики тромбоэмболии легочной артерии в пред-, интра- и постоперационном периоде. Из 627 обследованных пациентов, 473 больным проводилась, преимущественно, профилактика тромбоэмболии легочной артерии в пред-, интра- и постоперационном периоде, 154 пациентам - только в послеоперационном периоде. Полученный результат заболеваемости тромбоэмболией легочной артерии - 0,48%, относится только к больным, оперированным в срочном порядке. Смертность 0,16% варьирует в зависимости от сочетания предрасполагающих факторов. Было изучено несколько комбинированных методов профилактики. Приоритетным было сочетание механических методов (применение эластичного бинта на ногах) с гепаринами с низкой молекулярной массой. Исследование определялось повышением эффективности использования сочетания механических методов с еноксипарином (Klexan) в профилактике тромбоэмболии легочной артерии у пациентов с умеренным и высоким риском тромбоэмболии легочной артерии. Преимуществом еноксипарина и других низкомолекулярных гепаринов является то, что не требуется определение кровотечения и время свертывания крови во время приема. Также не определяются никакие изменения в количестве тромбоцитов у пациентов, получающих еноксипарин

Level-3 Calorimetric Resolution available for the Level-1 and Level-2 CDF Triggers

As the Tevatron luminosity increases sophisticated selections are required to be efficient in selecting rare events among a very huge background. To cope with this problem, CDF has pushed the offline calorimeter algorithm reconstruction resolution up to Level 2 and, when possible, even up to Level 1, increasing efficiency and, at the same time, keeping under control the rates. The CDF Run II Level 2 calorimeter trigger is implemented in hardware and is based on a simple algorithm that was used in Run I. This system has worked well for Run II at low luminosity. As the Tevatron instantaneous luminosity increases, the limitation due to this simple algorithm starts to become clear: some of the most important jet and MET (Missing ET) related triggers have large growth terms in cross section at higher luminosity. In this paper, we present an upgrade of the Level 2 Calorimeter system which makes the calorimeter trigger tower information available directly to a CPU allowing more sophisticated algorithms to be implemented in software. Both Level 2 jets and MET can be made nearly equivalent to offline quality, thus significantly improving the performance and flexibility of the jet and MET related triggers. However in order to fully take advantage of the new L2 triggering capabilities having at Level 1 the same L2 MET resolution is necessary. The new Level-1 MET resolution is calculated by dedicated hardware. This paper describes the design, the hardware and software implementation and the performance of the upgraded calorimeter trigger system both at Level 2 and Level 1.Comment: 5 pages, 5 figures,34th International Conference on High Energy Physics, Philadelphia, 200