GreenDelivery: Proactive Content Caching and Push with Energy-Harvesting-based Small Cells

The explosive growth of mobile multimedia traffic calls for scalable wireless access with high quality of service and low energy cost. Motivated by the emerging energy harvesting communications, and the trend of caching multimedia contents at the access edge and user terminals, we propose a paradigm-shift framework, namely GreenDelivery, enabling efficient content delivery with energy harvesting based small cells. To resolve the two-dimensional randomness of energy harvesting and content request arrivals, proactive caching and push are jointly optimized, with respect to the content popularity distribution and battery states. We thus develop a novel way of understanding the interplay between content and energy over time and space. Case studies are provided to show the substantial reduction of macro BS activities, and thus the related energy consumption from the power grid is reduced. Research issues of the proposed GreenDelivery framework are also discussed.Comment: 15 pages, 5 figures, accepted by IEEE Communications Magazin

Quantitative Susceptibility Mapping: Contrast Mechanisms and Clinical Applications.

Quantitative susceptibility mapping (QSM) is a recently developed MRI technique for quantifying the spatial distribution of magnetic susceptibility within biological tissues. It first uses the frequency shift in the MRI signal to map the magnetic field profile within the tissue. The resulting field map is then used to determine the spatial distribution of the underlying magnetic susceptibility by solving an inverse problem. The solution is achieved by deconvolving the field map with a dipole field, under the assumption that the magnetic field is a result of the superposition of the dipole fields generated by all voxels and that each voxel has its unique magnetic susceptibility. QSM provides improved contrast to noise ratio for certain tissues and structures compared to its magnitude counterpart. More importantly, magnetic susceptibility is a direct reflection of the molecular composition and cellular architecture of the tissue. Consequently, by quantifying magnetic susceptibility, QSM is becoming a quantitative imaging approach for characterizing normal and pathological tissue properties. This article reviews the mechanism generating susceptibility contrast within tissues and some associated applications

Enhanced photocatalytic degradation of ciprofloxacin over Bi2O3/(BiO)(2)CO3 heterojunctions: Efficiency, kinetics, pathways, mechanisms and toxicity evaluation

In this study, the degradation of antibiotic ciprofloxacin (CIP) over Bi2O3/(BiO)(2)CO3 heterojunctions under simulated solar light irradiation (SSL-Bi2O3/(BiO)(2)CO3) was examined for the first time. The results showed that the Bi2O3/(BiO)(2)CO3 heterojunctions dramatically improved CIP decay efficiency. The effect of parameters showed that the CIP decay was optimized with the Bi2O3/(BiO)(2)CO3 dosage of 0.5 g/L and a wide pH range of 4.0-8.3, based on which, a kinetic model was derived to predict the remaining CIP concentration. It was found that the presence of anions like SO42-, NO3- and HCO3- decelerated the CIP decay, while the co-existence of Cl- accelerated the CIP decay. Six degradation intermediates were identified by ultra-performance liquid chromatography coupled with mass analyzer (UPLC/MS) and ion chromatographic (IC) analysis, and the decay pathways and degradation mechanism of CIP were proposed by combining the experiment data with theoretical calculation of frontier electron densities. Hydroxyl radical's reaction, photo-hole (h(+)) oxidation and reductive defluorination were found to involve in the CIP decay. The efficient alleviation on total organic carbon (TOC) and toxicity indicated that the complete mineralization and de-toxicity are possible by this system with sufficient reaction time

Theoretical interpretation of the Ξ(1620)\Xi(1620) and Ξ(1690)\Xi(1690) resonances seen in Ξc+→Ξ−π+π+\Xi_c^+ \to \Xi^- \pi^+ \pi^+ decay

We study the Belle reaction $\Xi_c^+ \to \Xi^- \pi^+ \pi^+$ looking at the mass distribution of $\pi^+ \Xi$, where clear signals for the $\Xi(1620)$ and $\Xi(1690)$ resonances are seen. These two resonances are generated dynamically from the interaction in coupled channels of $\pi \Xi, \bar K \Lambda, \bar K \Sigma$ and $\eta \Xi$ within the chiral unitary approach. Yet, the weak decay process at the quark level, together with the hadronization to produce pairs of mesons, does not produce the $\pi \pi \Xi$ final state. In order to produce this state one must make transitions from the $\bar K \Lambda, \bar K \Sigma$ and $\eta \Xi$ components to $\pi \Xi$, and this interaction is what produces the resonances. So, the reaction offers a good test for the molecular picture of these resonances. Adding the contribution of the $\Xi^*(1530)$ and some background we are able to get a good reproduction of the mass distribution showing the signatures of the two resonances as found in the experiment.Comment: 15 pages, 8 figures, 2 tables; v2: discussion added, references added, version to appear in Eur.Phys.J.

PS-PVD thermal/environmental barrier coatings with novel microstructures

Plasma spray physical vapor deposition (PS-PVD) technology has attracted increasing attention due to it promising potential in processing advanced functional coatings such as thermal/environmental barrier coatings (TBCs) by flexibly tailoring the coating microstructure architecture in a broad range. In this work, yttria stabilized zirconia (YSZ) TBCs with a novel quasi-columnar structure was prepared by co-deposition of vapor phase and nano-clusters using PS-PVD and the associated deposition mechanism was discussed. The thermo-physical and mechanical properties, sintering resistance and thermal shock life of the coating were investigated. The thermal conductivity is in a range of 0.7~1.0 W/mk between 200 °C and 1200 °C and the average life is ~4000 cycles during thermal shock testing in which the coating surface was heated to 1200 °C within 20 s and held at the temperature for 5 min by gas flame. Noted that the quasi-columnar TBC revealed much better resistance to glassy CaO-MgO-Al2O3-SiO2 (CMAS) adsorption than those TBCs produced by air plasma spray (APS) and electron beam physical vapor deposition (EB-PVD) and some attempts were made to understand the related mechanisms. Ytterbium silicate/mullite/Si environmental barrier coatings (EBCs) were sprayed onto SiC ceramic matrix composites (CMC) by PS-PVD. The dense ytterbium silicate coating deposited at 65 kw is mainly composed of ytterbium disilicate resulting from vapor-phase deposition, whereas the layered coating at 40 kw is mainly ytterbium monosilicate from liquid deposition