3,110 research outputs found
On Companion-Induced Off-Center Supernova-Like Explosions
We suggest that a neutron star with a strong magnetic field, spiraling into
the envelope of a companion star, can generate a ``companion induced SN-like
off-center explosion". The strongly magnetized neutron star ("magnetar") is
born in a supernova explosion before entering into an expanding envelope of a
supergiant companion. If the neutron star collapses into a black hole via the
hypercritical accretion during the spiral-in phase, a rapidly rotating black
hole with a strong magnetic field at the horizon results. The Blandford-Znajek
power is sufficient to power a supernova-like event with the center of
explosion displaced from the companion core. The companion core, after
explosion, evolves into a C/O-white dwarf or a neutron star with a second
explosion. The detection of highly eccentric black-hole, C/O-white dwarf
binaries or the double explosion structures in the supernova remnants could be
an evidence of the proposed scenario.Comment: 5 page
Nonmonotonic behavior of resistance in a superconductor-Luttinger liquid junction
Transport through a superconductor-Luttinger liquid junction is considered.
When the interaction in the Luttinger liquid is repulsive, the resistance of
the junction with a sufficiently clean interface shows nonmonotonic
temperature- or voltage-dependence due to the competition between the
superconductivity and the repulsive interaction. The result is discussed in
connection with recent experiments on single-wall carbon nanotubes in contact
with superconducting leads.Comment: Revtex4, 2 eps figure files, slightly revised from an earlier version
submitted to PRL on 2001.12.
Mechanical rolling formation of interpenetrated lithium metal/lithium tin alloy foil for ultrahigh-rate battery anode
To achieve good rate capability of lithium metal anodes for high-energy-density batteries, one fundamental challenge is the slow lithium diffusion at the interface. Here we report an interpenetrated, three-dimensional lithium metal/lithium tin alloy nanocomposite foil realized by a simple calendering and folding process of lithium and tin foils, and spontaneous alloying reactions. The strong affinity between the metallic lithium and lithium tin alloy as mixed electronic and ionic conducting networks, and their abundant interfaces enable ultrafast charger diffusion across the entire electrode. We demonstrate that a lithium/lithium tin alloy foil electrode sustains stable lithium stripping/plating under 30mAcm(-2) and 5mAhcm(-2) with a very low overpotential of 20mV for 200 cycles in a commercial carbonate electrolyte. Cycled under 6C (6.6mAcm(-2)), a 1.0mAhcm(-2) LiNi0.6Co0.2Mn0.2O2 electrode maintains a substantial 74% of its capacity by pairing with such anode
Effect of the alkali insertion ion on the electrochemical properties of nickel hexacyanoferrate electrodes
Nickel hexacyanoferrate (NiHCFe) is an attractive cathode material in both aqueous and organic electrolytes due to a low-cost synthesis using earth-abundant precursors and also due to its open framework, Prussian blue-like crystal structure that enables ultra-long cycle life, high energy efficiency, and high power capability. Herein, we explored the effect of different alkali ions on the insertion electrochemistry of NiHCFe in aqueous and propylene carbonate-based electrolytes. The large channel diameter of the structure offers fast solid-state diffusion of Li+, Na+, and K+ ions in aqueous electrolytes. However, all alkali ions in organic electrolytes and Rb+ and Cs+ in aqueous electrolytes show a quasi-reversible electrochemical behavior that results in poor galvanostatic cycling performance. Kinetic regimes in aqueous electrolyte were also determined, highlighting the effect of the size of the alkali ion on the electrochemical properties.open3
Evaluation of normalization methods for microarray data
BACKGROUND: Microarray technology allows the monitoring of expression levels for thousands of genes simultaneously. This novel technique helps us to understand gene regulation as well as gene by gene interactions more systematically. In the microarray experiment, however, many undesirable systematic variations are observed. Even in replicated experiment, some variations are commonly observed. Normalization is the process of removing some sources of variation which affect the measured gene expression levels. Although a number of normalization methods have been proposed, it has been difficult to decide which methods perform best. Normalization plays an important role in the earlier stage of microarray data analysis. The subsequent analysis results are highly dependent on normalization. RESULTS: In this paper, we use the variability among the replicated slides to compare performance of normalization methods. We also compare normalization methods with regard to bias and mean square error using simulated data. CONCLUSIONS: Our results show that intensity-dependent normalization often performs better than global normalization methods, and that linear and nonlinear normalization methods perform similarly. These conclusions are based on analysis of 36 cDNA microarrays of 3,840 genes obtained in an experiment to search for changes in gene expression profiles during neuronal differentiation of cortical stem cells. Simulation studies confirm our findings
A STUDY ON THE TWO-ROW EFFECT IN THE SLOSHING PHENOMENON
In this study, changes in fluid impact loads inside a tank were examined according to a two-row tank arrangement in an LNG-FPSO (Liquefied Natural Gas-Floating Production Storage Offloading) vessel. The motion RAO (Response Amplitude Operator) of the LNG-FPSO, coupled with the sloshing phenomenon inside the tank, was calculated by using HydroStar by Bureau Veritas. The motion simulation in the tank was conducted under filling ratios of 30%H, 60%H, and 80%H. The RAO in each condition was calculated according to the one-row and the two-row tank arrangement. The motion response spectrum using the calculated RAO and the JONSWAP (Joint North Sea Wave Analysis Project) spectrum were computed by implementing irregular motion according to each filling ratio and tank arrangement. The sloshing phenomenon inside the tank was implemented by using a 6-DOF (Degree Of Freedom) sloshing motion platform; impact pressure on the walls of the tank was measured with pressure sensors installed inside the tank. The sloshing experiment was conducted under the three filling ratios in the one-row and the two-row tank arrangement and impact loads were compared under each filling ratio according to the one-row and the two-row tank arrangement
Proximity-Directed Labeling Reveals a New Rapamycin-Induced Heterodimer of FKBP25 and FRB in Live Cells
Mammalian target of rapamycin (mTOR) signaling is a core pathway in cellular metabolism, and control of the mTOR pathway by rapamycin shows potential for the treatment of metabolic diseases. In this study, we employed a new proximity biotin-labeling method using promiscuous biotin ligase (pBirA) to identify unknown elements in the rapamycin-induced interactome on the FK506-rapamycin binding (FRB) domain in living cells. FKBP25 showed the strongest biotin labeling by FRB-pBirA in the presence of rapamycin. Immunoprecipitation and immunofluorescence experiments confirmed that endogenous FKBP25 has a rapamycin-induced physical interaction with the FRB domain. Furthermore, the crystal structure of the ternary complex of FRB-rapamycin-FKBP25 was determined at 1.67-angstrom resolution. In this crystal structure we found that the conformational changes of FRB generate a hole where there is a methionine-rich space, and covalent metalloid coordination was observed at C2085 of FRB located at the bottom of the hole. Our results imply that FKBP25 might have a unique physiological role related to metallomics in mTOR signaling.ope
Simultaneous measurement of phase retardation and optic axis of a phase compensation film using an axially-symmetric sheared polymer network liquid crystal
A new method for simultaneously measuring the phase retardation and optic axis of a uniaxial compensation film is demonstrated using an axially-symmetric sheared polymer network liquid crystal (SPNLC). By overlaying a tested compensation film with a calibrated SPNLC cell between crossed polarizers, two dark spots are clearly observed in a CCD image. From the orientation direction and distance of these two spots, the optic axis and phase retardation value of the compensation film can be determined. This method is particularly useful for those optical systems whose optic axis and phase retardation are dynamically changing
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