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Multistaged discharge constructing heterostructure with enhanced solid-solution behavior for long-life lithium-oxygen batteries.
Inferior charge transport in insulating and bulk discharge products is one of the main factors resulting in poor cycling stability of lithium-oxygen batteries with high overpotential and large capacity decay. Here we report a two-step oxygen reduction approach by pre-depositing a potassium carbonate layer on the cathode surface in a potassium-oxygen battery to direct the growth of defective film-like discharge products in the successive cycling of lithium-oxygen batteries. The formation of defective film with improved charge transport and large contact area with a catalyst plays a critical role in the facile decomposition of discharge products and the sustained stability of the battery. Multistaged discharge constructing lithium peroxide-based heterostructure with band discontinuities and a relatively low lithium diffusion barrier may be responsible for the growth of defective film-like discharge products. This strategy offers a promising route for future development of cathode catalysts that can be used to extend the cycling life of lithium-oxygen batteries
Empirical metallicity-dependent calibrations of effective temperature against colours for dwarfs and giants based on interferometric data
We present empirical metallicity-dependent calibrations of effective
temperature against colours for dwarfs of luminosity classes IV and V and for
giants of luminosity classes II and III, based on a collection from the
literature of about two hundred nearby stars with direct effective temperature
measurements of better than 2.5 per cent. The calibrations are valid for an
effective temperature range 3,100 - 10,000 K for dwarfs of spectral types M5 to
A0 and 3,100 - 5,700 K for giants of spectral types K5 to G5. A total of
twenty-one colours for dwarfs and eighteen colours for giants of bands of four
photometric systems, i.e. the Johnson (), the Cousins
(), the Sloan Digital Sky Survey (SDSS, ) and the Two
Micron All Sky Survey (2MASS, ), have been calibrated. Restricted
by the metallicity range of the current sample, the calibrations are mainly
applicable for disk stars ([Fe/H]). The normalized percentage
residuals of the calibrations are typically 2.0 and 1.5 per cent for dwarfs and
giants, respectively. Some systematic discrepancies at various levels are found
between the current scales and those available in the literature (e.g. those
based on the infrared flux method IRFM or spectroscopy). Based on the current
calibrations, we have re-determined the colours of the Sun. We have also
investigated the systematic errors in effective temperatures yielded by the
current on-going large scale low- to intermediate-resolution stellar
spectroscopic surveys. We show that the calibration of colour ()
presented in the current work provides an invaluable tool for the estimation of
stellar effective temperature for those on-going or upcoming surveys.Comment: 28 pages, 19 figures, 8 tables, accepted for publication in MNRA
Observer-based fault-tolerant control for a class of networked control systems with transfer delays
Abstract not availableZehui Mao, Bin Jiang, Peng Sh
Dual-mode index modulation aided OFDM
Index modulation has become a promising technique in the context of orthogonal frequency division multiplexing (OFDM), whereby the specific activation of the frequency domain subcarriers is used for implicitly conveying extra information, hence improving the achievable throughput at a given bit error ratio (BER) performance. In this paper, a dual-mode OFDM technique (DM-OFDM) is proposed, which is combined with index modulation and enhances the attainable throughput of conventional index-modulation-based OFDM. Specifically, the subcarriers are divided into several subblocks, and in each subblock, all the subcarriers are partitioned into two groups, modulated by a pair of distinguishable modem-mode constellations, respectively. Hence the information bits are conveyed not only by the classic constellation symbols, but implicitly also by the specific activated subcarrier indices, representing the subcarriers’ constellation mode. At the receiver, a maximum likelihood (ML) detector and a reduced-complexity near optimal log-likelihood ratio (LLR) based detector are invoked for demodulation. The minimum distance between the different legitimate realizations of the OFDM subblocks is calculated for characterizing the performance of DM-OFDM. Then the associated theoretical analysis based on the pairwise error probability is carried out for estimating the BER of DM-OFDM. Furthermore, the simulation results confirm that at a given throughput DM-OFDM achieves a considerably better BER performance than other OFDM systems using index modulation, while imposing the same or lower computational complexity. The results also demonstrate that the performance of the proposed low-complexity detector is indistinguishable from that of the ML detector, provided that the system’s signal to noise ratio is sufficiently high
Tetraaquatetrakis(4,4′-bipyridine dioxide-κO)terbium(III) octacyanidotungstate(V)
In the title compound, [Tb(C10H8N2O2)4(H2O)4][W(CN)8], both metal atoms are eight-coordinated. The TbIII ion displays a dodecahedral geometry, while the Wv ion exhibits a distorted square-antiprismatic geometry. The Tb atoms are located on a special position of site symmetry -4, whereas the W atoms are located on a twofold rotation axis. The cations are linked by O—H⋯O hydrogen bonds. The title compound is isotypic with the corresponding and previously described Mo compound [Qian & Yuan (2011 ▶). Acta Cryst. E67, m845]
Testosterone Depletion by Castration May Protect Mice from Heat-Induced Multiple Organ Damage and Lethality
When the vehicle-treated, sham-operated mice underwent heat stress, the fraction survival and core temperature at +4 h of body heating were found to be 5 of 15 and 34.4°C ± 0.3°C, respectively. Castration 2 weeks before the start of heat stress decreased the plasma levels of testosterone almost to zero, protected the mice from heat-induced death (fraction survival, 13/15) and reduced the hypothermia (core temperature, 37.3°C). The beneficial effects of castration in ameliorating lethality and hypothermia can be significantly reduced by testosterone replacement. Heat-induced apoptosis, as indicated by terminal deoxynucleotidyl- transferase- mediatedαUDP-biotin nick end-labeling staining, were significantly prevented by castration. In addition, heat-induced neuronal damage, as indicated by cell shrinkage and pyknosis of nucleus, to the hypothalamus was also castration-prevented. Again, the beneficial effects of castration in reducing neuronal damage to the hypothalamus as well as apoptosis in multiple organs during heatstroke, were significantly reversed by testosterone replacement. The data indicate that testosterone depletion by castration may protect mice from heatstroke-induced multiple organ damage and lethality
Cross-Layer Software-Defined 5G Network
In the past few decades, the world has witnessed a rapid growth in mobile
communication and reaped great benefits from it. Even though the fourth
generation (4G) mobile communication system is just being deployed worldwide,
proliferating mobile demands call for newer wireless communication technologies
with even better performance. Consequently, the fifth generation (5G) system is
already emerging in the research field. However, simply evolving the current
mobile networks can hardly meet such great expectations, because over the years
the infrastructures have generally become ossified, closed, and vertically
constructed. Aiming to establish a new paradigm for 5G mobile networks, in this
article, we propose a cross-layer software-defined 5G network architecture. By
jointly considering both the network layer and the physical layer together, we
establish the two software-defined programmable components, the control plane
and the cloud computing pool, which enable an effective control of the mobile
network from the global perspective and benefit technological innovations.
Specifically, by the cross-layer design for software-defining, the logically
centralized and programmable control plane abstracts the control functions from
the network layer down to the physical layer, through which we achieve the
fine-grained controlling of mobile network, while the cloud computing pool
provides powerful computing capability to implement the baseband data
processing of multiple heterogeneous networks. We discuss the main challenges
of our architecture, including the fine-grained control strategies, network
virtualization, and programmability. The architecture significantly benefits
the convergence towards heterogeneous networks and it enables much more
controllable, programmable and evolvable mobile networks.Comment: 9 pages, 5 figures, submitted to Mobile Networks & Application
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