Formation of bulk unipolar diodes in hydrogenated amorphous siliconby ion implantation

Bulk unipolar diodes with a wide range of barrier heights have been made in hydrogenated amorphous silicon by ion implantation. The precise concentration of dopant atoms that can be obtained when implanting into an amorphous substrate leads to accurate barrier height control. Compared with the alternative unipolar device, the Schottky diode, these devices should provide uniform, high barrier diodes for photodetectors, and very low barrier diodes for low-power, unbiased, mixers and detectors     

Simple synthesis of ZnS nanoparticles in alkaline medium

ZnS nanoparticles were successfully synthesized by reflux under an alkaline medium. The nanoparticles were characterized by using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical properties of ZnS nanoparticles were examined by photoluminescence (PL) spectrum. The result shows that the as-synthesized ZnS nanoparticles had a cubic phase. SEM image shows that ZnS nanoparticles are basically in spherical shape and are homogeneous. The particle size was found to be in the range of 18 nm.     

An improved LC-MS/MS method for the quantitation of acrylamide in processed foods

An improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of acrylamide in processed foods. The homogenized samples, spiked with ¹³C₃-acrylamide as an internal standard, were extracted with water and centrifuged. D₅-3-chloropropanediol as a recovery standard was added to 1-ml aliquots, and the sample was purified with a C₁₈-cartridge column. The extract was directly analyzed using LC-MS/MS without derivatization. The ion transitions of 72–55 m/z (acrylamide), 75–58 m/z (¹³C₃-acrylamide), and 116–98 m/z (d₅-3-chloropropanediol) were found to be the most reliable for the identification and quantification of acrylamide in multiple reaction monitoring. The limit of quantification for acrylamide, defined as a signal-to-noise ratio of 10:1, was 2 μg/kg. The use of d₅-3-chloropropanediol minimized the effects of variation in the sample matrixes and increased the quality of analysis. This method could be applied to the quantification of acrylamide in processed foods.     

Identification of airway characteristics using the input impedance

To understand how the input impedance determined at the throat correlates with changes in the dynamic characteristics of the airways, a simplified 5-lobe model is developed and simulated. The model takes into account some realistic conditions such as varying cross-sectional areas, flexible wall properties and branching. The lobe terminal impedances are implemented in the model to predict the input impedance at the throat. The effects of airway constrictions and wall elastance variations on this impedance are determined for a range of frequencies. It is concluded that the developed model is capable of predicting various physiological changes in the airway passages.     

Monitoring of a radiation recovery in neutron-irradiated RPV steel by using the magnetic methods

The effects of a neutron irradiation on the magnetic parameters of a reactor pressure vessel (RPV) steel with different microstructures, partially due to a difference in the steel refining processes were investigated. The samples were irradiated in a research reactor with a fluence of 4.5 × 10¹⁹ n/cm² at 288 °C. The measurement of the Barkhausen noise (BN) was conducted to explore the relationship between the microstructural state and the domain wall motion. The BN profiles of the unirradiated samples showed a consistent change with the microstructure (grain size, carbide morphology, lath width), but the neutron-irradiated sample did not show a consistent change with microstructural state. The radiation hardening and recovery characteristics have been investigated by using the Vickers hardness method, and the relationship between the BN and the microhardness is obtained for four different steels. The linear relationship between mechanical and magnetic properties can be used as a nondestructive evaluation for radiation damage.     

Compiler-directed cache management in multiprocessors

The necessity of finding alternatives to hardware-based cache coherence strategies for large-scale multiprocessor systems is discussed. Three different software-based strategies sharing the same goals and general approach are presented. They consist of a simple invalidation approach, a fast selective invalidation scheme, and a version control scheme. The strategies are suitable for shared-memory multiprocessor systems with interconnection networks and a large number of processors. Results of trace driven simulations conducted on numerical benchmark routines to compare the performance of the three schemes are presented     

Synergizing spatial and temporal texture

Temporal texture accounts for a large proportion of motion commonly experienced in the visual world. Current temporal texture techniques extract primarily motion-based features for recognition. We propose a representation where both the spatial and the temporal aspects of texture are coupled together. Such a representation has the advantages of improving efficiency as well as retaining both spatial and temporal semantics. Flow measurements form the basis of our representation. The magnitudes and directions of the normal flow are mapped as spatiotemporal textures. These textures are then aggregated over time and are subsequently analyzed by classical texture analysis tools. Such aggregation traces the history of a motion which can be useful in the understanding of motion types. By providing a spatiotemporal analysis, our approach gains several advantages over previous implementations. The strength of our approach was demonstrated in a series of experiments, including classification and comparisons with other algorithms.     

The Relationship Between Flow Paths and Water Quality in Mine Water Oxidation Ponds in South Korea

Tests were carried out at passive mine water treatment sites in South Korea to determine how flow and pH affected other water quality parameters. Computational flow analysis and tracer tests revealed that the water took surprisingly direct flow routes in the oxidation ponds, while other areas remained stagnant. Furthermore, ferrous iron concentration, dissolved oxygen, pH, electrical conductivity, total dissolved solids, turbidity, and water depth were all directly affected by the flow patterns due to the relationship between retention time and iron precipitation.