Harnessing optical micro-combs for microwave photonics

In the past decade, optical frequency combs generated by high-Q micro-resonators, or micro-combs, which feature compact device footprints, high energy efficiency, and high-repetition-rates in broad optical bandwidths, have led to a revolution in a wide range of fields including metrology, mode-locked lasers, telecommunications, RF photonics, spectroscopy, sensing, and quantum optics. Among these, an application that has attracted great interest is the use of micro-combs for RF photonics, where they offer enhanced functionalities as well as reduced size and power consumption over other approaches. This article reviews the recent advances in this emerging field. We provide an overview of the main achievements that have been obtained to date, and highlight the strong potential of micro-combs for RF photonics applications. We also discuss some of the open challenges and limitations that need to be met for practical applications.Comment: 32 Pages, 13 Figures, 172 Reference

Computational model of 18650 lithium-ion battery with coupled strain rate and SOC dependencies

Highly nonlinear structures and constituent materials and hazardous experiment situations have resulted in a pressing need for a numerical mechanical model for lithium-ion battery (LIB). However, such a model is still not well established. In this paper, an anisotropic homogeneous model describing the jellyroll and the battery shell is established and validated through compression, indentation, and bending tests at quasi-static loadings. In this model, state-of-charge (SOC) dependency of the LIB is further included through an analogy with the strain-rate effect. Moreover, with consideration of the inertia and strain rate effects, the anisotropic homogeneous model is extended into the dynamic regime and proven capable of predicting the dynamic response of the LIB using the drop-weight test. The established model may help to predict extreme cases with high SOCs and crashing speeds with an over 135% improved accuracy compared to traditional models. The established coupled strain rate and SOC dependencies of the numerical mechanical model for the LIB aims to provide a solid step toward unraveling and quantifying the complicated problems for research on LIB mechanical integrity. (C) 2016 Elsevier Ltd. All rights reserved

Ductile Metallic Glasses in Supercooled Martensitic Alloys

We report ductile bulk metallic glasses based on martensitic alloys. The slowly cooled specimens contain a mixture of parent 'austenite' and martensite phase. The slightly faster cooled bulk metallic glasses with 2-5 nm sized 'austenite'-like crystalline cluster reveal high strength and large ductility (16%). Shear bands propagate in a slither mode in this spatially inhomogeneous glassy structure and undergo considerable 'thickening' from 5-25 nm. A 'stress induced displacive transformation' is proposed to be responsible for both plasticity and work-hardening-like behavior of these 'M-Glasses'

Polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in the equatorial Indian Ocean: Temporal trend, continental outflow and air-water exchange

Nineteen pairs of air and seawater samples collected from the equatorial Indian Ocean onboard the Shiyan I from 4/2011 to 5/2011 were analyzed for PCBs and HCB. Gaseous concentrations of Sigma(ICES)PCBs (ICES: International Council for the Exploration of the Seas) and HCB were lower than previous data over the study area. Air samples collected near the coast had higher levels of PCBs relative to those collected in the open ocean, which may be influenced by proximity to source regions and air mass origins. Dissolved concentrations of Sigma(ICES)PCBs and HCB were 1.4-14 pg L-1 and 0.94-13 pg L-1, with the highest concentrations in the sample collected from Strait of Malacca. Fugacity fractions suggest volatilization of PCBs and HCB from the seawater to air during the cruise, with fluxes of 0.45-34 ng m(-2) d(-1) and 0.36-18 ng m(-2) d(-1), respectively. (c) 2014 Elsevier Ltd. All rights reserved.Nineteen pairs of air and seawater samples collected from the equatorial Indian Ocean onboard the Shiyan I from 4/2011 to 5/2011 were analyzed for PCBs and HCB. Gaseous concentrations of Sigma(ICES)PCBs (ICES: International Council for the Exploration of the Seas) and HCB were lower than previous data over the study area. Air samples collected near the coast had higher levels of PCBs relative to those collected in the open ocean, which may be influenced by proximity to source regions and air mass origins. Dissolved concentrations of Sigma(ICES)PCBs and HCB were 1.4-14 pg L-1 and 0.94-13 pg L-1, with the highest concentrations in the sample collected from Strait of Malacca. Fugacity fractions suggest volatilization of PCBs and HCB from the seawater to air during the cruise, with fluxes of 0.45-34 ng m(-2) d(-1) and 0.36-18 ng m(-2) d(-1), respectively. (c) 2014 Elsevier Ltd. All rights reserved

Honeytubes: Hollow lattice truss reinforced honeycombs for crushing protection

Lattice truss reinforced honeycombs (LTRHs), termed honeytubes, were developed based on a hybrid design of micro-lattice truss and square honeycomb topologies. Carbon fiber reinforced composite and polymer LTRHs were fabricated using different manufacturing approaches. Out-of-plane compression tests were performed on the LTRHs, and the properties were compared with the conventional square honeycombs. The stiffness and strength values of composite LTRHs didn't surpass those of composite square honeycombs due to the manually induced defects. On the other hand, polymeric LTRHs with perfect geometries were stiffer and stronger than the corresponding polymeric square honeycombs. A parametric study of the buckling resistance was carried out via finite element analysis, and the results indicated that hollow lattice stiffens honeycombs and increases the resistance to buckling, while the specific properties of honeytubes depend on their geometrical parameters. Moreover, the crush force efficiency and specific energy absorption were greater than those of square honeycombs and hollow lattice. This work demonstrates that hybrid designs that capitalize on micro-topologies can populate vacant regions in mechanical property charts, and provide increased energy absorption as crushing protection structures. (C) 2016 Elsevier Ltd. All rights reserved

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

A mesoscale modelling perspective of cracking process and fracture energy under high strain rate in tension

This paper presents a numerical modelling study on the simulation of the cracking process and fracture energy in concrete under high strain rate. To capture the stress wave effect and the damage evolution at the meso-length scale, both a homogeneous model with a millimetreresolution mesh and an explicit heterogeneous mesoscale model with random polygon aggregates are employed. The tendency of development of a) discrete multiple cracks, and b) spread tensile damage across adjacent element layers, in the high strain rate tension regime is scrutinised. This phenomenon generally gives rise to an increase in the dynamic fracture energy, which is consistent with experimental observations. Relative comparison between the homogeneous and heterogeneous mesoscale simulations suggests a sensible effect of the mesoscopic heterogeneity in the dynamic fracture process.Structural EngineeringCivil Engineering and Geoscience

Optimization and model-based control for max-plus linear and continuous piecewise affine systems

This PhD thesis considers the development of optimization and model-based control techniques for max-plus linear (MPL) and continuous piecewise affine (PWA) systems. The three main topics investigated in this thesis are as follows: 1. Optimistic optimization and planning for model-based control of MPL systems; 2. Optimistic optimization for MPC of continuous PWA systems; 3. MPC for stochastic MPL systems with chance constraintsHybrid, Adaptive and Nonlinea

Affective Body Language of Humanoid Robots: Perception and Effects in Human Robot Interaction

Intelligent SystemsElectrical Engineering, Mathematics and Computer Scienc