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Effective, permanent tuning of the whispering gallery modes (WGMs) of p-i-n doped GaN microdisk cavity with embedded InGaN quantum dots over one free spectral range is demonstrated by irradiating the microdisks with a ultraviolet laser (380 nm) in DI wat

Controlled tuning of the whispering gallery modes of GaN/InGaN microdisk cavities is demonstrated. The whispering gallery mode (WGM) tuning is achieved at room temperature by immersing the microdisks in water and irradiating with ultraviolet laser. The t

The formation of single-crystal diamond membranes is an important prerequisite for the fabrication of high-quality optical cavities in this material. Diamond membranes fabricated using lift-off processes involving the creation of a damaged layer through

A system that can automatically detect nodules within lung images may assist expert radiologists in interpreting the abnormal patterns as nodules in 2D CT lung images. A system is presented that can automatically identify nodules of various sizes within lung images. The pattern classification method is employed to develop the proposed system. A random forest ensemble classifier is formed consisting of many weak learners that can grow decision trees. The forest selects the decision that has the most votes. The developed system consists of two random forest classifiers connected in a series fashion. A subset of CT lung images from the LIDC database is employed. It consists of 5721 images to train and test the system. There are 411 images that contained expert- radiologists identified nodules. Training sets consisting of nodule, non-nodule, and false-detection patterns are constructed. A collection of test images are also built. The first classifier is developed to detect all nodules. The second classifier is developed to eliminate the false detections produced by the first classifier. According to the experimental results, a true positive rate of 100%, and false positive rate of 1.4 per lung image are achieved.

A method is presented for identification of lung nodules. It includes three stages: image acquisition, background removal, and nodule detection. The first stage improves image quality. The second stage extracts long lobe regions. The third stage detects lung nodules. The method is based on the random forest learner. Training set contains nodule, non-nodule, and false-positive patterns. Test set contains randomly selected images. The developed method is compared against the support vector machine. True-positives of 100% and 85.9%, and false-positives of 1.27 and 1.33 per image were achieved by the developed method and the support vector machine, respectively.

A method is presented that achieves lung nodule detection by classification of nodule and non-nodule patterns. It is based on random forests which are ensemble learners that grow classification trees. Each tree produces a classification decision, and an integrated output is calculated. The performance of the developed method is compared against that of the support vector machine and the decision tree methods. Three experiments are performed using lung scans of 32 patients including thousands of images within which nodule locations are marked by expert radiologists. The classification errors and execution times are presented and discussed. The lowest classification error (2.4%) has been produced by the developed method.

Lung modelling has emerged as a useful method for diagnosing lung diseases. Image segmentation is an important part of lung modelling systems. The ill-defined nature of image segmentation makes automated lung modelling difficult. Also, low resolution of lung images further increases the difficulty of the lung image segmentation. It is therefore important to identify a suitable segmentation algorithm that can enhance lung modelling accuracies. This paper investigates six image segmentation algorithms, used in medical imaging, and also their application to lung modelling. The algorithms are: normalised cuts, graph, region growing, watershed, Markov random field, and mean shift. The performance of the six segmentation algorithms is determined through a set of experiments on realistic 2D CT lung images. An experimental procedure is devised to measure the performance of the tested algorithms. The measured segmentation accuracies as well as execution times of the six algorithms are then compared and discussed.

Automated 3D lung modeling involves analyzing 2D lung images and reconstructing a realistic 3D model of the lung. This paper presents a review of the existing works on automatic formation of 3D lung models from 2D lung images. A common framework for 3D lung modeling is proposed. It consists of eight components: image acquisition, image pre-processing, image segmentation, boundary creation, image recognition, image registration, 3D surface reconstruction, and 3D rendering and visualization. The algorithms used by the existing systems to implement these components are also reviewed.

This paper presents an analytical model of fuel consumption (AMFC) to coordinate the driving power and manage the overall fuel consumption for an internal combustion engine vehicle. The model calculates the different loads applied on the vehicle including road-slope, road-friction, wind-drag, accessories, and mechanical losses. Also, it solves the combustion equation of the engine under different working conditions including various fuel compositions, excess airs and air inlet temperatures. Then it determines the contribution of each load to signify the energy distribution and power flows of the vehicle. Unlike the conventional models in which the vehicle speed needs to be given as an input, the developed model can predict the vehicle speed and acceleration under different working conditions by allowing the speed to vary within a predefined range only. Furthermore, the model indicates the ways to minimises the vehicles' fuel consumption under various driving conditions. The results show that the model has the potential to assist in the vehicle energy management.

The quality factors of modes in nearly identical GaAs and Al0.18Ga0.82As microdisks are tracked over three wavelength ranges centered at 980, 1460, and 1600 nm, with quality factors measured as high as 6.62×10^5 in the 1600 nm band. After accounting for surface scattering, the remaining loss is due to sub-band-gap absorption in the bulk and on the surfaces. The observed absorption is, on average, 80% greater in AlGaAs than in GaAs and is 540% higher in both materials at 980 nm than at 1600 nm.

This papers reports the advances in optical core networks research coordinated in the framework of the e- photon/ONe and e-photon/ONe+ networks of excellence., QC 20120305

Heat generation in fabrics coated with the conductive polymer polypyrrole was investigated. The PET fabrics were coated by chemical synthesis using four different oxidizing agent-dopant combinations. The samples from the four different dopant systems all show an increase in temperature when a fixed voltage is applied to the fabric. The antraquinone-2-sulfonic acid (AQSA) sodium salt doped polypyrrole coating was the most effective in heat generation whereas the sodium Perchlorate dopant system was the least effective. The power density per unit area achieved in polypyrrole coated polyester-Lycra(R) fabric with 0.027 mol/l of AQSA acting as dopant was 430 W/m(2). The power density per unit area achieved for the sodium Perchlorate system, using the same synthesis conditions, was 55 W/m(2)., QC 20110926

AlGaN/GaN current aperture vertical electron transistor (CAVET) was fabricated and optimized for band gap selective photoelectrochemical wet etching. The large polarization induced voltage offset (around 2.5-4 eV) observed in the first generation CAVET was reduced to 0.7 V in this structure by employing a delta Si doping layer buried 60 Angstrom below the In0.03Ga0.97N (60 nm thick) and bottom GaN interface to screen the polarization fields. Other sample structures were studied to achieve an aperture with both good undercut etching and a small voltage offset. It was clearly demonstrated that etch selectivity in the GaN/InGaN/GaN undercut structures was influenced by hole confinement and the chemical activity of the N-face GaN. (C) 2004 American Institute of Physics.

An improved three-arm airbridge contacted microdisk diode structure is presented. Continuous-wave lasing from InGaAs quantum dot (QD) in a ~4-micron-diameter microdisks is reported with the threshold current ~40 uA at T = 5 K. With the increase of injection current, the QD's emission blueshifts due to the band-filling effect, while the laser mode peak redshifts by thermal effect. When the QD's gain spectra shift out of alignment with the lasing mode, the next available whispering gallery mode starts lasing from QD wetting layer. The thermal heating effect is discussed by investigating the modes redshift with respect to injection current.

Polarity and dislocation dependence study of photoelectrochemical wet etching on GaN was carried out on lateral epitaxial overgrown nonpolar (11 (2) over bar0)a-GaN/(1 (1) over bar 02)r-plane sapphire substrate. This LEO nonpolar GaN sample has low dislocation density Ga- and N-faces exposed horizontally in opposite directions, which can be exposed to identical etching conditions for both polarity and dislocation dependence study. It is observed that N-face GaN is essentially much chemically active than Ga-face GaN, which shows the hexagonal pyramids with {10 (1) over bar(1) over bar} facets on the etched N face. No obvious etching was observed on Ga face in the same etch condition. As for dislocation dependence, the "wing" (low dislocation density) region was etched faster than the "window" (high dislocation density) region. Smooth etched surfaces were formed with the ((1) over bar(1) over bar2 (2) over bar) facet as an etch stop plane both on Ga and N-wing region. (C) 2004 American Institute of Physics.

We report the results of an extensive spectroscopic survey of galaxies in the roughly 160 square arcminute ACS-GOODS region surrounding the HDF-N. We have identified 787 galaxies or stars with z'<24, R<24.5, or B<25 lying in the region. The spectra were obtained with either the DEIMOS or LRIS spectrographs on the Keck 10m telescopes. The results are compared with photometric redshift estimates and with redshifts from the literature, as well as with the redshifts of a parallel effort led by a group at Keck. Our sample, when combined with the literature data, provides identifications for 1180 sources. We use our results to determine the redshift distributions with magnitude, to analyze the rest-frame color distributions with redshift and spectral type, and to investigate the dependence of the X-ray galaxy properties on the local galaxy density in the redshift interval z=0-1.5. We find the rather surprising result that the galaxy X-ray properties are not strongly dependent on the local galaxy density for galaxies in the same luminosity range., Comment: Submitted to the Astronomical Journal

This work discusses the fabrication of two-dimensional photonic crystal microcavities (PCMs) in a thin GaAs membrane. We have developed a fabrication process for square-lattice, single-hole-defect devices, a class of PCMs that is critically sensitive to fabrication accuracy, demonstrated coupling of InAs quantum dots to the cavity modes, and shown the sensitivity of the emission to the quality of the fabrication process. Reactive ion etching conditions were optimized to produce photonic crystal holes with smooth, straight sidewalls. To achieve, uniform hole sizes throughout the device, we developed a method to correct the proximity effect introduced while defining the photonic crystal holes using electron-beam lithography. Resulting cavities have resonances with quality factors as high as 4000, which proves the quality of our fabrication. (C) 2003 American Vacuum Society.

We have conducted a deep multi-color imaging survey of 0.2 degrees^2 centered on the Hubble Deep Field North (HDF-N). We shall refer to this region as the Hawaii-HDF-N. Deep data were collected in U, B, V, R, I, and z' bands over the central 0.2 degrees^2 and in HK' over a smaller region covering the Chandra Deep Field North (CDF-N). The data were reduced to have accurate relative photometry and astrometry across the entire field to facilitate photometric redshifts and spectroscopic followup. We have compiled a catalog of 48,858 objects in the central 0.2 degrees^2 detected at 5 sigma significance in a 3" aperture in either R or z' band. Number counts and color-magnitude diagrams are presented and shown to be consistent with previous observations. Using color selection we have measured the density of objects at 35.5 using the Lyman break technique suffer from more contamination by low redshift objects than suggested by previous studies., Comment: 57 pages, 24 figures, 14 tables Accepted by AJ, data and catalogs available at http://www.ifa.hawaii.edu/~capak/hdf