421 research outputs found

    Pseudo-gap features of intrinsic tunneling in (HgBr_2)-Bi2212 single crystals

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    The c-axis tunneling properties of both pristine Bi2212 and its HgBr2_2 intercalate have been measured in the temperature range 4.2 - 250 K. Lithographically patterned 7-10 unit-cell heigh mesa structures on the surfaces of these single crystals were investigated. Clear SIS-like tunneling curves for current applied in the c\it c-axis direction have been observed. The dynamic conductance dI/I/dV(V)V(V) shows both sharp peaks corresponding to a superconducting gap edge and a dip feature beyond the gap, followed by a wide maximum, which persists up to a room temperature. Shape of the temperature dependence of the {\it c}-axis resistance does not change after the intercalation suggesting that a coupling between CuO2\rm CuO_2-bilayers has little effect on the pseudogap.Comment: 6 pages, 5 figures; presented at the Second Int Conf. New3Sc-1999 (Las Vegas, NV

    Toxic effects of ammonia exposure on growth performance, hematological parameters, and plasma components in rockfish, Sebastes schlegelii, during thermal stress

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    Abstract Rockfish, Sebastes schlegelii (mean length 14.53 ± 1.14 cm and mean weight 38.36 ± 3.45 g), were exposed for 4 weeks with the different levels of ammonia in the concentrations of 0, 0.1, 0.5, and 1.0 mg/L at 19 and 24 °C. The indicators of growth performance such as daily length gain, daily weight gain, condition factor, and hematosomatic index were significantly reduced by the ammonia exposure and high temperature. The ammonia exposure induced a significant decrease in hematological parameters, such as red blood cell (RBC) count, white blood cell (WBC) count, hemoglobin (Hb), and hematocrit (Ht), whose trend was more remarkable at 24 °C. Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were also notably decreased by the ammonia exposure. Blood ammonia concentration was considerably increased by the ammonia concentration exposure. In the serum components, the glucose, glutamic oxalate transaminase (GOT), and glutamic pyruvate transaminase (GPT) were substantially increased by the ammonia exposure, whereas total protein was significantly decreased. But, the calcium and magnesium were not considerably changed

    Unusual transport characteristics of nitrogen-doped single-walled carbon nanotubes

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    Electrical transport characteristics of nitrogen-doped single-walled carbon nanotubes (N-SWCNTs), in which the nitrogen dopant is believed to form a pyridinelike bonding configuration, are studied with the field effect transistor operations. Contrary to the expectation that the nitrogen atoms may induce a n -type doping, the electrical transports through our N-SWCNTs are either ambipolar in vacuum or p -type in air. Through the first-principles electronic structure calculations, we show that the nitrogen dopant indeed favors the pyridinelike configuration and the Fermi level of the pyridinelike N-SWCNT is almost at the intrinsic level.open01

    Recent advances and perspectives for intercalation layered compounds. Part 2: applications in the field of catalysis, environment and health

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    Intercalation compounds represent a unique class of materials that can be anisotropic (1D and 2D-based topology) or isotropic (3D) through their guest/host superlattice repetitive organisation. Intercalation refers to the reversible introduction of guest species with variable natures into a crystalline host lattice. Different host lattice structures have been used for the preparation of intercalation compounds, and many examples are produced by exploiting the flexibility and the ability of 2D-based hosts to accommodate different guest species, ranging from ions to complex molecules. This reaction is then carried out to allow systematic control and fine tuning of the final properties of the derived compounds, thus allowing them to be used for various applications. This review mainly focuses on the recent applications of intercalation layered compounds (ILCs) based on layered clays, zirconium phosphates, layered double hydroxides and graphene as heterogeneous catalysts, for environmental and health purposes, aiming at collecting and discussing how intercalation processes can be exploited for the selected applications

    Recent advances and perspectives on intercalation layered compounds part 1: design and applications in the field of energy

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    Herein, initially, we present a general overview of the global financial support for chemistry devoted to materials science, specifically intercalation layered compounds (ILCs). Subsequently, the strategies to synthesise these host structures and the corresponding guest–host hybrid assemblies are exemplified on the basis of some families of materials, including pillared clays (PILCs), porous clay heterostructures (PCHs), zirconium phosphate (ZrP), layered double hydroxides (LDHs), graphite intercalation compounds (GICs), graphene-based materials, and MXenes. Additionally, a non-exhaustive survey on their possible application in the field of energy through electrochemical storage, mostly as electrode materials but also as electrolyte additives, is presented, including lithium technologies based on lithium ion batteries (LIBs), and beyond LiBs with a focus on possible alternatives such XIBs (X = Na (NIB), K (KIB), Al (AIB), Zn (ZIB), and Cl (CIB)), reversible Mg batteries (RMBs), dual-ion batteries (DIBs), Zn-air and Zn-sulphur batteries and supercapacitors as well as their relevance in other fields related to (opto)electronics. This selective panorama should help readers better understand the reason why ILCs are expected to meet the challenge of tomorrow as electrode materials
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