13,859 research outputs found

    A Ballistic Graphene Cooper Pair Splitter

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    We report an experimental study of Cooper pair splitting in an encapsulated graphene based multiterminal junction in the ballistic transport regime. Our device consists of two transverse junctions, namely the superconductor/graphene/superconductor and the normal metal/graphene/normal metal junctions. In this case, the electronic transport through one junction can be tuned by an applied bias along the other. We observe clear signatures of Cooper pair splitting in the local as well as nonlocal electronic transport measurements. Our experimental data can be very well described by using a modified Octavio-Tinkham-Blonder-Klapwijk model and a three-terminal beam splitter model

    On quantum plasma: a plea for a common sense

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    The quantum plasma theory has flourished in the past few years without much regard to the physical validity of the formulation or its connection to any real physical system. It is argued here that there is a very limited physical ground for the application of such a theory.Comment: EPL, to be published 201

    Ion thermal effects in oscillating multi-ion plasma sheath theory

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    The effects of ion temperature are discussed in a two-ion electron plasma and for a model applicable to the oscillating sheath theory that has recently been much in the focus of researchers. The differences between the fluid and kinetic models have been pointed out, as well as the differences between the approximative kinetic description (which involves the expansion of the plasma dispersion function), and the exact kinetic description. It is shown that the approximative kinetic description, first, can not describe the additional acoustic mode which naturally exists in the plasma with an additional ion population with a finite temperature, and, second, it yields an inaccurate Landau damping of the bulk ion acoustic mode. The reasons for these two failures are described. In addition to this, a fluid model is presented that is capable of capturing both of these features that are missing in the approximative kinetic description, i.e., two (fast and slow) ion acoustic modes, and the corresponding Landau damping of both modes

    Pre-main-sequence population in NGC 1893 region: X-ray properties

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    Continuing the attempt to understand the properties of the stellar content in the young cluster NGC 1893 we have carried out a comprehensive multi-wavelength study of the region. The present study focuses on the X-ray properties of T-Tauri Stars (TTSs) in the NGC 1893 region. We found a correlation between the X-ray luminosity, LXL_X, and the stellar mass (in the range 0.2-2.0 \msun) of TTSs in the NGC 1893 region, similar to those reported in some other young clusters, however the value of the power-law slope obtained in the present study (\sim 0.9) for NGC 1893 is smaller than those (\sim1.4 - 3.6) reported in the case of TMC, ONC, IC 348 and Chameleon star forming regions. However, the slope in the case of Class III sources (Weak line TTSs) is found to be comparable to that reported in the case of NGC 6611 (\sim 1.1). It is found that the presence of circumstellar disks has no influence on the X-ray emission. The X-ray luminosity for both CTTSs and WTTSs is found to decrease systematically with age (in the range \sim 0.4 Myr - 5 Myr). The decrease of the X-ray luminosity of TTSs (slope \sim -0.6) in the case of NGC 1893 seems to be faster than observed in the case of other star-forming regions (slope -0.2 to -0.5). There is indication that the sources having relatively large NIR excess have relatively lower LXL_X values. TTSs in NGC 1893 do not follow the well established X-ray activity - rotation relation as in the case of main-sequence stars.Comment: 10 pages, 7 figures, Accepted for publication in New Astronom

    Search For A Permanent Electric Dipole Moment Using Atomic Indium

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    We propose indium (In) as a possible candidate for observing the permanent electric dipole moment (EDM) arising from the violations of parity (P) and time-reversal (T) symmetries. This atom has been laser cooled and therefore the measurement of its EDM has the potential of improving on the current best EDM limit for a paramagnetic atom which comes from thallium. We report the results of our calculations of the EDM enhancement factor due to the electron EDM and the ratio of the atomic EDM to the electron-nucleus scalar-pseudoscalar (S-PS) interaction coupling constant in In in the framework of the relativistic coupled cluster theory. It might be possible to get new limits for the electron EDM and the S-PS CP violating coupling constant by combining the results of our calculations with the measured value of the EDM of In when it is available. These limits could have important implications for the standard model (SM) of particle physics.Comment: 5 pages, 1 fig, Rapid Communicatio

    Corresponding Conductance in Aqueous & Non-aqueous Media

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    Production of both esters and biogas from Mexican poppy

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    This paper details a dynamic evaluation of a procedure for extracting both, ester and biogas from seeds and waste of Mexican poppy (Argemone mexicana) using simple and inexpensive technique. Results showed that A. mexicana seed contains 30% oil. Through the process of transestrification, oil extracted from seed, has been converted to its ester. Methanol gives good separation of ester with A. mexicana compared to ethanol and A. mexicana methyl ester showed closer physical property to diesel. Calorific value of seed waste was 4621 Kcal/Kg and C/N ratio was 11. The experiment for biogas production was accomplished in two conditions viz sunlight (22- 30°C) and at room temperature (16-20°C) for 33 days. Sunlight increase ten times biogas production compared to room temperature. Biogas produced through anaerobic digestion of seed waste contained 52% methane. This process is suitable for smallscale industries and agricultural farms.Key words: Transestrification, energy conservation, anaerobic digestion, methane, biogas, methyl ester
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