Investigating vibration dyanmics of cross-coupled MEMS resonators for reduced motional resistance

This paper investigates the vibration dynamics of a closed-chain, cross-coupled architecture of MEMS resonators. The system presented here is electrostatically transduced and operates at 1.04 MHz. Curve veering of the eigenvalue loci is used to experimentally quantify the coupling spring constants. Numerical simulations of the motional resistance variation against induced perturbation are used to assess the robustness of the cross-coupled system as opposed to equivalent traditional open-ended linear one-dimensional coupling scheme. Results show improvements of as much as 32% in the motional resistance between the cross-coupled system and its one-dimensional counterpart. © 2013 IEEE.

On-chip focusing of light by metallic nanotip

We present a numerical simulations, fabrication and experimental results for on-chip focusing of surface plasmon polaritons (SPPs) in metal nanotip coupled to the silicon waveguide © 2011 OSA.

Inkjet printing of weakly elastic polymer solutions

Fluid assessment methods, requiring small volumes and avoiding the need for jetting, are particularly useful in the design of functional fluids for inkjet printing applications. With the increasing use of complex (rather than Newtonian) fluids for manufacturing, single frequency fluid characterisation cannot reliably predict good jetting behaviour, owing to the range of shearing and extensional flow rates involved. However, the scope of inkjet fluid assessments (beyond achievement of a nominal viscosity within the print head design specification) is usually focused on the final application rather than the jetting processes. The experimental demonstration of the clear insufficiency of such approaches shows that fluid jetting can readily discriminate between fluids assessed as having similar LVE characterisation (within a factor of 2) for typical commercial rheometer measurements at shearing rates reaching 104rads-1.Jetting behaviour of weakly elastic dilute linear polystyrene solutions, for molecular weights of 110-488. kDa, recorded using high speed video was compared with recent results from numerical modelling and capillary thinning studies of the same solutions.The jetting images show behaviour ranging from near-Newtonian to "beads-on-a-string". The inkjet printing behaviour does not correlate simply with the measured extensional relaxation times or Zimm times, but may be consistent with non-linear extensibility L and the production of fully extended polymer molecules in the thinning jet ligament.Fluid test methods allowing a more complete characterisation of NLVE parameters are needed to assess inkjet printing feasibility prior to directly jetting complex fluids. At the present time, directly jetting such fluids may prove to be the only alternative. © 2014 The Authors.

Graphene passively Q-switched two-micron fiber lasers

We demonstrate a passively Q-switched thulium fiber laser, using a graphene-based saturable absorber. The laser is based on an all-fiber ring cavity and produces ~2.3 μs pulses at 1884nm, with a maximum pulse energy of 70 nJ. ©2011 Optical Society of America.

Material point method for coupled hydromechanical problems

This paper describes a new formulation of the material point method (MPM) for solving coupled hydromechanical problems of fluid-saturated soil subjected to large deformation. A soil-pore fluid coupled MPM algorithm based on Biot's mixture theory is proposed for solving hydromechanical interaction problems that include changes in water table location with time. The accuracy of the proposed method is examined by comparing the results of the simulation of a one-dimensional consolidation test with the corresponding analytical solution. A sensitivity analysis of the MPM parameters used in the proposed method is carried out for examining the effect of the number of particles per mesh and mesh size on solution accuracy. For demonstrating the capability of the proposed method, a physical model experiment of a large-scale levee failure by seepage is simulated. The behavior of the levee model with time-dependent changes in water table matches well to the experimental observations. The mechanisms of seepage-induced failure are discussed by examining the pore-water pressures, as well as the effective stresses computed from the simulations © 2013 American Society of Civil Engineers.

Determination of sexual hormones in liquid cosmetics by polymer monolith microextraction coupled with high performance liquid chromatography

A method was presented for the determination of testosterone, methyltestosterone and progesterone in liquid cosmetics by coupling polymer monolith microextraction (PMME) to high performance liquid chromatography with UV detection. A poly (methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column was selected as the extraction medium, which showed high extraction capacity towards these compounds. To achieve optimum extraction performance, several parameters relating to PMME were investigated, including extraction flow rate and pH value, inorganic salt and organic phase concentration of the sample matrix. By simple dilution with phosphate solution and filtering, the sample solution then could be directly injected into the device for extraction. The limits of detection of testosterone, methyltestosterone and progesterone were calculated to be 2, 3, 2, 8 and 4.6 mu g/L. Good linearity was achieved in the range of 10 to 1000 mu g/L with a linear coefficient. r value above 0. 996. Excellent method reproducibility was found by intra- and inter-day precisions, yielding the relative standard deviations of < 7. 7 % and < 7. 5 %, respectively. Recovery for them in the real samples was between 83% and 119%.

Subcellular localization and characterization of G protein-coupled receptor homolog from lymphocystis disease virus isolated in China

G protein-coupled receptors (GPCRs) constitute a large superfamily involved in various types of signal transduction pathways, and play an important role in coordinating the activation and migration of leukocytes to sites of infection and inflammation. Viral GPCRs, on the other hand, can help the virus to escape from host immune surveillance and contribute to viral pathogenesis. Lymphocystis disease virus isolated in China (LCDV-C) contains a putative homolog of cellular GPCRs, LCDV-C GPCR. In this paper, LCDV-C GPCR was cloned, and the subcellular localization and characterization of GPCR protein were investigated in fish cells. LCDV-C GPCR encoded a 325-amino acid peptide, containing a typical seven-transmembrane domain characteristic of the chemokine receptors and a conserved DRY motif that is usually essential for receptor activation. Transient transfection of GPCR-EGFP in fathead minnow (FHM) cells and epithelioma papulosum cyprini (EPC) cells indicated that LCDV-C GPCR was expressed abundantly in both the cytoplasm and nucleoplasm. Transient overexpression of GPCR in these two cells cannot induce obvious apoptosis. FHM cells stably expressing GPCR showed enhanced cell proliferation and significant anchorage-independent growth. The effects of GPCR protein on external apoptotic stimuli were examined. Few apoptotic bodies were observed in cells expressing GPCR treated with actinomycin D (ActD). Quantitative analysis of apoptotic cells indicated that a considerable decrease in the apoptotic fraction of cells expressing GPCR, compared with. the control cells, was detected after exposure to ActD and cycloheximide. These data suggest that LCDV-C GPCR may inhibit apoptosis as part of its potential mechanism in mediating cellular transformation.

First demonstration of a full C-band tunable WDM-PON system with novel high-temperature DS-DBR lasers

We demonstrate automatic operation of a cooler-less tunable-laser based WDM-PON system. Using a pilot-tone based overhead channel and centralized wavelength locking scheme, 1 Gb/s and 10 Gb/s data transmission is demonstrated in a multi-user set-up. © 2013 Optical Society of America.

Dynamic simulation of mode-locked quantum-dot lasers

A dynamic model of passive mode-locking in quantum-dot laser diodes is presented. It is found that in contrast with quantum-well lasers, rapid gain recovery is key for mode-locking of quantum-dot lasers. © 2008 Optical Society of America.

Semantic transform: Weakly supervised semantic inference for relating visual attributes

Relative (comparative) attributes are promising for thematic ranking of visual entities, which also aids in recognition tasks. However, attribute rank learning often requires a substantial amount of relational supervision, which is highly tedious, and apparently impractical for real-world applications. In this paper, we introduce the Semantic Transform, which under minimal supervision, adaptively finds a semantic feature space along with a class ordering that is related in the best possible way. Such a semantic space is found for every attribute category. To relate the classes under weak supervision, the class ordering needs to be refined according to a cost function in an iterative procedure. This problem is ideally NP-hard, and we thus propose a constrained search tree formulation for the same. Driven by the adaptive semantic feature space representation, our model achieves the best results to date for all of the tasks of relative, absolute and zero-shot classification on two popular datasets. © 2013 IEEE.

Vertically-coupled microring laser array for dual-wavelength generation

We report the first demonstration of continuous-wave operation of a tunable, compact microring laser array based on a vertical-coupling architecture, well suited to larger-scale integration. Wavelength separation tunability from 4.9 to 6.3nm is observed. © 2006 Optical Society of America.

FM mode-locking in monolithic semiconductor lasers

FM mode-locking in monolithic semiconductor lasers is investigated for the first time, using a travelling-wave laser model. The effects of phase modulation depth and non-zero alpha factor on pulse quality and pulse-width are discussed. © 2004 Optical Society of America.

FM mode-locking in monolithic semiconductor lasers

FM mode-locking in monolithic semiconductor lasers is investigated for the first time, using a travelling-wave laser model. The effects of phase modulation depth and non-zero alpha factor on pulse quality and pulse-width are discussed. © 2004 Optical Society of America.