The SIMIAN architecture-an object-orientated framework for integrated power system modelling, analysis and control

This paper details the work conducted by the Brunel Institute of Power Systems, UK, into an object orientated framework for power systems modelling, analysis and control. Based around a central OODBMS (object orientated database management system), the architecture provides a framework for the construction of analysis and control applications and the sharing of calculated or real-time data between the applications. Although the paper details the architecture only in so far as its applicability to two applications, the framework is designed such that further applications, either client output (such as control applications) or input(such as SCADA systems) may easily be added to the basic structure. To illustrate the architecture, a load flow simulation application is presented, along with the strategy for incorporating other applications. The mechanism by which these `applications' interact with the OODBMS and core structure of the architecture is illustrate

Multi-detector x-ray mapping and generation of correction factor images for problem solving

X-ray mapping with Silicon Drift detectors (SDD’s) and multi-EDS detector systems has become an invaluable analysis technique because the time to perform an x-ray map is reduced considerably. Live x-ray imaging can now been performed with so much data collected in a matter of minutes. The use of multi-EDS detector systems has made this form of mapping even quicker and has also given users the ability to map minor and trace elements very accurately. How the data is collected and summed with multi-EDS detectors is very critical for accurate quantitative x-ray mapping (QXRM). There is a great deal of further information that can be obtained from x-ray maps. This includes elemental relationship or scatter diagram creation, elemental ratio mapping, chemical phase mapping (CPM) and quantitative x-ray maps. In obtaining quantitative x-ray maps we are able to easily generate atomic number (Z), absorption (A), fluorescence (F), theoretical back scatter coefficient (η) and a quantitative total maps from each pixel in the image. This allows us to generate an image corresponding to each factor (for each element present). These images allow us to predict and verify where we are likely to have problems in our images, and are especially helpful to look at possible interface artefacts

Depletion layer imaging using a gaseous secondary electron detector in an environmental scanning electron microscope

Abstract : We present a method for imaging depletion layers using the gaseous secondary electron detector (GSED) employed in environmental scanning electron microscopes. GSED images of a p-np-n junction were obtained from a Si P+PNP+PN power diode. Behavior of the junction contrast as a function of imaging conditions is unrelated to reported GSED contrast formation mechanisms [ A. L. Fletcher, B. L. Thiel, and A. M. Donald, J. Phys. D 30, 2249 (1997)]. Optimum imaging conditions are presented, and the contrast behavior is interpreted in terms of a previously unreported induced current component in GSED images. The presented technique is unique as it will enable imaging of depletion layers in uncoated semiconductor/oxide devices in controlled gaseous environments at elevated specimen temperatures

X-ray mapping and post processing

Characterisation of materials frequently involves the determination of variation in composition, structure and microstructure, by the use of a variety of imaging and analysis techniques. There is an increasing need to understand materials phenomena and processes and to learn more about exploiting subtle changes in the distribution of elements in materials technology. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), wavelength dispersive spectroscopy (WDS) and the combination of these techniques through x-ray mapping (XRM) has become an excellent tool for characterising the distribution of elements and phases in materials. This analytical technique provides a high magnification image related to the distribution and relative abundance of elements within a given specimen and thus makes XRM particularly useful for: • identifying the location of individual elements and • mapping the spatial distribution of specific elements and phases within a sample (material surface). Quantitative x-ray mapping (QXRM) enables reliable quantitative results that can be an order of magnitude better than traditional analysis and is also far superior to regions of interest x-ray maps (ROIM) where low levels of an element or elemental overlaps are present

Dynamic surface site activation: A rate limiting process in electron beam induced etching

We report a new mechanism that limits the rate of electron beam induced etching (EBIE). Typically, the etch rate is assumed to scale directly with the precursor adsorbate dissociation rate. Here, we show that this is a special case, and that the rate can instead be limited by the concentration of active sites at the surface. Novel etch kinetics are expected if surface sites are activated during EBIE, and observed experimentally using the electron sensitive material ultra nanocrystalline diamond (UNCD). In practice, etch kinetics are of interest because they affect resolution, throughput, proximity effects, and the topography of nanostructures and nanostructured devices fabricated by EBIE. © 2013 American Chemical Society

Role of Hospice Care at the End of Life for People With Cancer.

Patient-defined factors that are important at the end of life include being physically independent for as long as possible, good symptom control, and spending quality time with friends and family. Hospice care adds to the quality of care and these patient-centered priorities for people with cancer and their families in the last weeks and days of life. Evidence from large observational studies demonstrate that hospice care can improve outcomes directly and support better and more appropriate health care use for people in the last stages of cancer.Team-based community hospice care has measurable benefits for patients, their family caregivers, and health services. In addition to improved symptom control for patients and a greater likelihood of time spent at home, caregiver outcomes are better when hospice care is accessed: informational needs are better met, and caregivers have an improved ability to move on with life after the patient's death compared with people who did not have access to these services.Hospice care continues to evolve as its reach expands and the needs of patients continue to broaden. This is reflected in the transition from hospice being based on excellence in nursing to teams with a broad range of health professionals to meet the complex and changing needs of patients and their families. Additional integration of cancer services with hospice care will help to provide more seamless care for patients and supporting family caregivers during their caregiving and after the death of the patient

Cathodoluminescence inhomogeneity in ZnO nanorods

Luminescence properties of vertically aligned, crystalline ZnO nanorods are studied by cathodoluminescence (CL) spectroscopy and microscopy. Results show that luminescence characteristics vary dramatically with location on the nanorod as well as CL excitation depth. CL inhomogeneity is observed between the nanorod tip and sidewalls, accompanied by a variation in the chemical environment of surface oxygen ions as probed by photoemission spectroscopy. Our findings demonstrate that CL can provide useful information on the local optical properties of nanostructured materials, which is simply beyond the capability of other methods. © 2008 American Institute of Physics

Distribution of visible luminescence centers in hydrogen-doped ZnO

ZnO crystals have been investigated by scanning cathodoluminescence microscopy and spectroscopy at 80 K following hydrogen incorporation by plasma exposure. The intensity of the ZnO near-band-edge (NBE) emission is greatly enhanced while the defect-related green emission is quenched following plasma treatment. These effects are attributed to the passivation of zinc vacancies by hydrogen. The green and yellow intensities and their intensity ratios to the NBE vary with excitation depth for both undoped and H-doped ZnO crystals. The intensities of the green and yellow emissions exhibit sublinear dependencies on electron beam excitation density while the NBE intensity increases linearly with the excitation density. These saturation effects with increasing excitation density must be taken into account when assessing defects in ZnO by luminescence characterization. © Copyright Materials Research Society 2011