Luby Transform Coding Aided Iterative Detection for Downlink SDMA Systems

A Luby Transform (LT) coded downlink Spatial Division Multiple Access (SDMA) system using iterative detection is proposed, which invokes a low-complexity near-Maximum-Likelihood (ML) Sphere Decoder (SD). The Ethernet-based Internet section of the transmission chain inflicts random packet erasures, which is modelled by the Binary Erasure Channel (BEC), which the wireless downlink imposes both fading and noise. A novel log-Likelihood Ratio based packet reliability metric is used for identifying the channel-decoded packets, which are likely to be error-infested. Packets having residual errors must not be passed on to the KT decoder for the sake of avoiding LT-decoding –induced error propagation. The proposed scheme is capable of maintaining an infinitesimally low packet error ratio in the downlink of the wireless Internet for Eb/n0 values in excess of about 3dB

The hyperon mean free paths in the relativistic mean field

The $\Lambda$- and $\Xi^-$-hyperon mean free paths in nuclei are firstly calculated in the relativistic mean field (RMF) theory. The real parts of the optical potential are derived from the RMF approach, while the imaginary parts are obtained from those of nucleons with the relations: $U^{\mathrm{IY}}_{\mathrm{S}} = \alpha_{\sigma \mathrm{Y}}\cdot U_{\mathrm{S}}^{\mathrm{IN}}$ and $U^{\mathrm{IY}}_{\mathrm{V}} = \alpha_{\omega \mathrm{Y}}\cdot U_{\mathrm{V}}^{\mathrm{IN}}$ . With the assumption, the depth of the imaginary potential for $\Xi^-$ is $W_{\Xi}\simeq-$ 3.5 MeV, and for $\Lambda$ is $W_{\Lambda}\simeq-$ 7 MeV at low incident energy. We find that, the hyperon mean free path decreases with the increase of the hyperon incident energies, from 200 MeV to 800 MeV; and in the interior of the nuclei, the mean free path is about $2\sim 3$ fm for $\Lambda$, and about $4\sim 8$ fm for $\Xi^-$, depending on the hyperon incident energy.Comment: 5 figures, 6 page

Effect of Wine Closures on the Aroma Properties of Chardonnay Wines after Four Years of Storage

The effects of wine closures on the sensory properties and aroma profiles of fresh Chardonnay wines wereevaluated after four years of bottle storage. Natural cork closure, technical cork closure, Nomacorc light,Nomacorc classic and Nomacorc premium were investigated. Among these wines sealing with differentclosures, the physicochemical parameters of the wine samples showed no significant differences, exceptthat of the free and total sulphur dioxide. Nomacorc light with the highest OTR (oxygen transition rate)had the least residual free sulphur dioxide. Most of volatiles were generally stable, and seven compounds(acetoin, 1-butanol, 2-phenylethanol, 1-pentanol, (Z)-3-hexen-1-ol, 2-nonanol and ethyl decanoate) weresignificantly affected by the wine closures. The sensory analysis revealed that cork closures preserved morefruity/flowery characters of the fresh wines after four years’ storage, as well as cork-tainted off-flavour.Two synthetic closures (Nomacorc light, Nomacorc classic) imparted some grilled attributes to the wines.Nomacorc premium highly reserved the fruity/flowery flavour without cork contamination or oxidisedtoasted characters

Singularity Free Inhomogeneous Models with Heat Flow

We present a class of singularity free exact cosmological solutions of Einstein's equations describing a perfect fluid with heat flow. It is obtained as generalization of the Senovilla class [1] corresponding to incoherent radiation field. The spacetime is cylindrically symmetric and globally regular.Comment: 6 pages, TeX, to appear in Class.Quant.Gra

Photocatalytic Nitrogen Reduction by Ti₃C₂ MXene Derived Oxygen Vacancy‐Rich C/TiO₂

In this work, oxygen vacancy‐rich C/TiO_{2} (OV‐C/TiO_{2}) samples are prepared by a one‐step calcination approach using Ti_{3}C_{2} MXene as the precursor, and used for the photocatalytic N_{2} reduction. The NH_{3} yields of all the prepared OV‐C/TiO_{2} samples exceed those achieved on commercial anatase TiO_{2} and P25, with both H_{2}O and CH_{3}OH as the proton sources. Among them, the OV‐C/TiO_{2}‐600 offers the remarkable NH3 synthesis rates, which are 41.00 µmol g^{−1} h^{−1} (with CH_{3}OH as the proton source). The photocurrent and fluorescence spectra show that OV‐C/TiO_{2}‐600 exhibit the highest generation/separation rate and longest lifetime of photocarriers among all the prepared samples. ESR and TPD experiments confirm much more efficient chemisoption of N_{2} on the surface of the prepared OV‐C/TiO_{2}‐600 than that on the surface of the commercial anatase TiO_{2}. Moreover, DFT calculations further demonstrate that N2 conversion to NH_{3} through a Gibbs free energy release leading alternating pathway with a low energy barriers, on the oxygen vacancy on TiO_{2} surface

CACNA1C polymorphisms Impact Cognitive Recovery in Patients with Bipolar Disorder in a Six-week Open-label Trial

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Interference Mitigation for the GPS Receiver Utilizing the Cyclic Spectral Analysis and RR-MSWF Algorithm

A method utilizing the cyclic spectral analysis (CSA) and reduced-rank multistage Wiener filtering (RR-MSWF) algorithm to mitigate the interference for the GPS receiver is proposed. In many cases, interference from adjacent channel or from cochannel overlaps on the weak global positioning system (GPS) signal in both time and frequency domains, and it is hard to mitigate this kind of strong interference with the conventional filtering techniques. While with the proposed method given in the paper, we can mitigate the interference effectively. The general process of the proposed method is that first we get the cyclic frequencies (CFs) of the strong interference by CSA of the received GPS signal. And then with the obtained CFs of the interference, we use the blind adaptive frequency shift (BA-FRESH) filter to get the principal process of mitigating the strong interference and separating the weak GPS signal. Finally by utilizing the efficient RR-MSWF algorithm to implement the BA-FRESH filtering, we can mitigate the strong interference effectively and hence improve the performance of the GPS receiver

New Family of Robust 2D Topological Insulators in van der Waals Heterostructures

We predict a new family of robust two-dimensional (2D) topological insulators in van der Waals heterostructures comprising graphene and chalcogenides BiTeX (X=Cl, Br and I). The layered structures of both constituent materials produce a naturally smooth interface that is conducive to proximity induced new topological states. First principles calculations reveal intrinsic topologically nontrivial bulk energy gaps as large as 70-80 meV, which can be further enhanced up to 120 meV by compression. The strong spin-orbit coupling in BiTeX has a significant influence on the graphene Dirac states, resulting in the topologically nontrivial band structure, which is confirmed by calculated nontrivial Z2 index and an explicit demonstration of metallic edge states. Such heterostructures offer an unique Dirac transport system that combines the 2D Dirac states from graphene and 1D Dirac edge states from the topological insulator, and it offers new ideas for innovative device designs

Novel Mechanism of Supersolid of Ultracold Polar Molecules in Optical Lattices

We study the checkerboard supersolid of the hard-core Bose-Hubbard model with the dipole-dipole interaction. This supersolid is different from all other supersolids found in lattice models in the sense that superflow paths through which interstitials or vacancies can hop freely are absent in the crystal. By focusing on repulsive interactions between interstitials, we reveal that the long-range tail of the dipole-dipole interaction have the role of increasing the energy cost of domain wall formations. This effect produces the supersolid by the second-order hopping process of defects. We also perform exact quantum Monte Carlo simulations and observe a novel double peak structure in the momentum distribution of bosons, which is a clear evidence for supersolid. This can be measured by the time-of-flight experiment in optical lattice systems

Photoluminescence and photoluminescence excitation studies of lateral size effects in Zn_{1-x}Mn_xSe/ZnSe quantum disc samples of different radii

Quantum disc structures (with diameters of 200 nm and 100 nm) were prepared from a Zn_{0.72}Mn_{0.28}Se/ZnSe single quantum well structure by electron beam lithography followed by an etching procedure which combined dry and wet etching techniques. The quantum disc structures and the parent structure were studied by photoluminescence and photoluminescence excitation spectroscopy. For the light-hole excitons in the quantum well region, shifts of the energy positions are observed following fabrication of the discs, confirming that strain relaxation occurs in the pillars. The light-hole exciton lines also sharpen following disc fabrication: this is due to an interplay between strain effects (related to dislocations) and the lateral size of the discs. A further consequence of the small lateral sizes of the discs is that the intensity of the donor-bound exciton emission from the disc is found to decrease with the disc radius. These size-related effects occur before the disc radius is reduced to dimensions necessary for lateral quantum confinement to occur but will remain important when the discs are made small enough to be considered as quantum dots.Comment: LaTeX2e, 13 pages, 6 figures (epsfig