Fluorescence line narrowing spectroscopy of polycyclic aromatic hydrocarbons on solid-liquid extraction membranes

The potential of solid-liquid extraction fluorescence line narrowing spectroscopy is evaluated for screening polycyclic aromatic hydrocarbons in aqueous samples. Octadecyl silica membranes are used with the dual purpose of sample preconcentration and solid substrate for spectroscopic measurements. 4.2 K fluorescence line narrowed spectra are directly recorded from the membrane with the aid of a fiber-optic probe. The experimental procedure is free from organic solvents and takes less than 5 min per sample. With 10 mL of water sample, the limits of detection are at the parts-per-billion level. Qualitative analysis is based on wavelength time matrices, which provide a unique format for compound identification based on spectral and lifetime data. The selectivity of this approach is demonstrated with the unambiguous determination of naphthalene in a heavily contaminated water sample.     

Accurate Gate Impedance Determination on Ultraleaky MOSFETs by Fitting to a Three-Lumped-Parameter Model atFrequencies From DC to RF

We present an experimental methodology that demonstrates the suitability of the conventional three-lumped- parameter model for gate impedance of MOSFET devices at frequencies from dc to the gigahertz range, which permits accurate extraction of model parameters. The parasitic effects at a high frequency are minimized by using radio frequency techniques (i.e., short return paths and de-embedding structures), whereas a robust parameter extraction algorithm overcomes possible instrument inaccuracies. When combined, these allow simultaneous extraction of all three parameters (i.e., C_gate, R_DT and R_series) from the model. The technique is applied to conventional SiO₂ -based MOSFET devices and to ultraleaky HfO₂ devices with aggressively scaled gate dielectric thickness.     

Analysis of adaptive sampling techniques for underwater vehicles

A critical problem in planning sampling paths for autonomous underwater vehicles (AUVs) is correctly balancing two issues. First, obtaining an accurate scalar field estimation and second, efficiently utilizing the stored energy capacity of the sampling vehicle. Adaptive sampling approaches can only provide solutions when real time and a priori environmental data is available. In this paper we present an analysis of adaptive sampling methodologies for AUVs. In particular, we analyze various sampling path strategies including systematic and stratified random patterns within a wide range of sampling densities and their impact in the energy consumption of the vehicle through a cost-evaluation function. Our study demonstrates that a systematic spiral sampling path strategy is optimal for high-variance scalar fields for all sampling densities and low-variance scalar fields when sampling is sparse. In addition, our results show that the random spiral sampling path strategy is found to be optimal for low-variance scalar fields when sampling is dense.     

Color tracking with contextual switching: real-time implementation on CPU

Journal of Real-Time Image Processing - The paper proposes contributions for mean-shift (MS) and covariance tracking (CT), and makes these two complementary methods cooperate. While MS runs fast...     

Inverting a forest canopy reflectance model to retrieve the overstorey and understorey leaf area index for forest stands

In this article, the Kuusk–Nilson forest reflectance and transmittance (FRT) model was inverted to retrieve the overstorey and understorey leaf area index (OU-LAI) of forest stands in the Longmenhe forest nature reserve in China. Data from detailed sample sites were collected in 30 forest stands representing the typical vegetation community in the study area. An uncertainty and sensitivity matrix (USM) was used to analyse the sensitivity of the FRT model parameters based on these data. The results indicated that overstorey LAI strongly influenced stand reflectance, whereas understorey LAI had a much lower impact. To predict OU-LAI in forest stands, FRT model inversion is carried out by minimizing a merit function that provides a measure of the difference between the reflectance simulated by the FRT model and the reflectance originating from optimal band selection of Hyperion data. Various combinations of Hyperion bands were tested to evaluate the most effective wavelengths for the inversion of OU-LAI. The best estimates from 17 Hyperion bands (5 VIS, 8 NIR, 4 SWIR) by the FRT model inversion showed an R ²?=?0.41 and RMSE/mean?=?0.21 for overstorey LAI and R ²?=?0.49 and RMSE/mean?=?0.91 for understorey LAI. Advantages and disadvantages of FRT inversion for retrieval OU-LAI combined with Hyperion data are discussed.     

Influence of oxygen on the sputtering of aluminum oxide for the surface passivation of crystalline silicon

While sputtering has been shown to be capable of depositing aluminum oxide suitable for surface passivation, the mechanisms for this are yet to be firmly established and its potential realized. In this paper, we investigate the relationships between the oxygen in the sputtering process to the resulting composition of the deposited film and the surface passivation obtained. We find that surface passivation is not strongly dependent on the bulk composition of the film. Instead the results indicate that the interfacial silicon oxide layer that forms after annealing between the aluminum oxide film and the silicon is a much more important factor; it is this combined structure of aluminum oxide, silicon oxide and silicon that is crucial for obtaining negative charges and excellent surface passivation.     

人机界面的演进

术语．“人机界面”突然间已进入技术领域专用词汇的行列，就其最基本词义而言，该术语不仅用于描述设备外观，更可以描述人与设备之间的交互过程。虽然这不是一个新概念，但是该技术能够彻底改变我们与电子设备交互方式的可用性，以及集成该技术的紧迫性表明用户对界面设计日益重视。     

Nonlinear vibrations and hysteresis of micromachined silicon resonators designed as frequency-out sensors

Experimental observation of nonlinear vibrations and hysteresis of micromachined silicon resonators is reported. The experimental results are explained using a simple model in which the restoring force acting in the resonator contains a small cubic term. The effects will impose a limit to the maximum amplitude which can be excited while still maintaining reliability of these devices as frequency-out sensors.     

Narrative interaction: creating a space for therapeutic communication

This theoretical article explores the impact of ethnic appearance on the nurse-client encounter from the perspective of Chicanas, women of Mexican descent. The issues raised for Chicanas, however, are applicable for members of many other ethnic groups, individuals whose identity is often constructed from the stereotypes and myths their appearance evokes. Ethnic minority women often experience a feeling of double jeopardy, enduring the consequences of living in a society that devalues both women and members of specific racial or ethnic groups. Research from nursing, counseling psychology, and sociology provide the bases for an examination of the mental health consequences of this double jeopardy. Narrative interaction, the sharing of personal stories, is offered as a therapeutic form of communication. Through narrative interactions, nurses may begin to understand the context of women's lives and learn what is meaningful for them, from their perspective. It is from the women themselves that nurses will begin to learn new meanings for their appearance and gain some understanding of their world.