1,169 research outputs found

    Evanescently-coupled hybrid III-V/silicon laser based on DVS-BCB bonding

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    © 2014 IEEE. Controllable electrical breakdown of multiwall nanotubes (MWNTs) is studied utilizing the atomic force microscopy (AFM). Electrical breakdown has been known as the way to fundamentally understand the electrical properties of nanotubes and an approach to develop MWNT based transistors and sensors. Normally, electrical breakdown was known to be happened in the center of MWNT because of the thermal accumulation. However, considering the effect of thermal dissipation, the electrical breakdown could be mechanically controlled by an additional heat sink, which could be the substrate of MWNT device. Therefore, the electrical breakdown process is controllable through controlling Joule heating and thermal dissipation. In this research, we study the crucial factors that affect the electrical breakdown. The AFM based nano robot is used to measure the conductance distribution, and manipulate the three dimensional structure of MWNT in order to change the position of heat sink to control the location where electrical breakdown happened. The controllable electrical breakdown is an alternative approach for conducting bandgap engineering in nanodevice and fabricating high performance nano sensors and transistors.Link_to_subscribed_fulltex

    Examining Mental Health and Well-being Provision in Schools in Europe: Methodological Approach

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    Schools are considered an ideal setting for community-based mental health and well-being interventions for young people. However, in spite of extensive literature examining the effectiveness of such interventions, very few studies have investigated existing mental health and well-being provision in schools. The current study aims to extend such previous research by surveying primary and secondary schools to investigate the nature of available provision in nine European countries (Germany, Ireland, the Netherlands, Poland, Serbia, Spain, Sweden, the UK and Ukraine). Furthermore, the study aims to investigate potential barriers to mental health and well-being provision and compare provision within and between countries

    Hybrid III-V/Si distributed-feedback laser based on adhesive bonding

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    A hybrid evanescently coupled III-V/silicon distributed-feedback laser with an integrated monitor photodiode, based on adhesive divinyl siloxane-benzocyclobutene bonding and emitting at 1310 nm, is presented. An output power of similar to 2.85 mW is obtained in a continuous wave regime at 10 degrees C. The threshold current is 20 mA and a sidemode suppression ratio of 45 dB is demonstrated. Optical feedback is provided via corrugations on top of the silicon rib waveguide, while a specially developed bonding procedure yields 40-nm-thick adhesive bonding layers, enabling efficient evanescent coupling

    Application of plants in remediation of contaminated sites

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    The concern for environmental protection has existed since the time of first human civilization. As society develops, the chain of changes during the natural flow of processes in ecosystems has been supplemented by a new link - pollutants. They have an effect on all other members of the ecosystem (changes may be visible immediately or harder to spot), which leads to an extremely complex relationship with nature. The values of some parameters of pollutants reached an alarmingly high level. The tendency to reduce the risk of air, soil, water, plant, and animal pollution to a tolerable limit, which would salvage the environment and most importantly human health, became a global problem. Heavy metals as pollutants have been an interest of researchers for their conduct, especially in forest ecosystems, which has been expressed in the previous year's more than ever. With its numerous toxic effects, heavy metals are endangering the existence of plant species that live in already contaminated environments. This is all an argument regarding the fight of modern society that the emission of polluted materials gets reduced in order to avoid multiple negative effects, which can endanger the existence of living organisms in general, as an argument for the continuation of numerous researches that are conducted in this area. The monitoring of heavy metals is of significant importance because their toxicity and accumulations are vital for the ecosystem. Polluted soils can be reduced and they can restore their function using physical, chemical, and biological techniques. Physical and chemical methods are very expensive and cause mainly irreversible changes, thus destroying biological variety. The biological recovery of contaminated soil represents an efficient method of reducing health risks for both mankind and the ecosystem.  For this purpose, biological indicators are used. Numerous researches have led to improvements of the initial idea about using plants as a remediation of the environment and the removal of different contaminants from contaminated medias into promising technologies of environmental protection under the title "Phytoremediation". This technology consists of the reduction of concentrations of polluted materials in polluted soils, water, or air. Plants have the ability to store, degrade, or eliminate metals, pesticides, solutions, explosives, and crude oils. Its derivatives and various other contaminants form mediums that contain them. This paper especially considers methods of the possibility of the usage and application of plants in restoring soil contaminated by heavy metals as well as other pollutants

    Mayfly ecological traits in a European karst spring: species, microhabitats and life histories

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    Despite the recent increase in the number of mayfly studies in karst freshwater habitats, their biology and ecology in springs are still poorly characterized. Therefore, we studied mayfly assemblages in a European karst rheocrene spring at five microhabitats monthly over a one-year period. Three species were recorded: Baetis alpinus (Pictet, 1843), Baetis rhodani (Pictet, 1843) and Rhithrogena braaschi (Jacob, 1974). The latter species represents a new record for the fauna of Bosnia and Herzegovina. All three species inhabited all studied microhabitats but with varying abundance. Individual species were associated with a specific substrate type and/or water velocity and/or water depth. The grazer/scraper Rh. braaschi was most common at microhabitats with inorganic substrate (cobbles, mixture of pebbles and sand), moderate water velocity and higher water depth. The rheophilic grazer/scraper and gatherer/collector B. alpinus was most common at microhabitats with mosses and highest water velocity. The grazer/scraper and gatherer/collector B. rhodani was recorded at all microhabitats, yet due to its preference for moderate water velocity, the highest number of individuals were collected from cobbles. We recorded movements of mayfly nymphs among the available microhabitats during their life cycles, due likely to their dietary requirements and search for suitable refugia. Baetis alpinus has a bivoltine, B. rhodani polyvoltine and Rh. braaschi univoltine life cycle with a long emergence period. The results presented here contribute to the knowledge of spring and mayfly ecology

    Supplementary information for: "Binding of metal ions and water molecules to nucleic acid bases: The influence of water molecule coordination to a metal ion on water–nucleic acid base hydrogen bonds"

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    Figure S1. Distance distribution for hydrogen bonds with coordinated and noncoordinated water, separately for different nucleic bases and positions; Table S1. The calculated interaction energies and distances between five nucleic bases and noncoordinated water molecules, at the B3LYP-D3/def2-TZVP (kcal/mol) and corrected for BSSE), MP2/def2-QZVP (kcal/mol) and noncorrected for BSSE) and CCSD(kcal/mol) and T)/CBS level; Table S2. The calculated interaction energies and distances at the B3LYP-D3/def2-TZVP level between five nucleic bases and water molecules coordinated to Zn2+ ion; Table S3. A number of hydrogen bonds between nucleic bases and coordinated water, and percentage of [M(H2O)n]x+ complexes, with different kinds of metals. Figure S2. Electrostatic potential maps for the nucleic bases. Figure S3. Distribution of the distance between water oxygen and nucleic base oxygen/nitrogen found in PDB structures for noncoordinated and coordinated water;Supplementary information for: Andrić, Jelena M., Stanković, Ivana, Zarić, Snežana D., "Binding of metal ions and water molecules to nucleic acid bases: The influence of water molecule coordination to a metal ion on water–nucleic acid base hydrogen bonds" in Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 75 (2019):301-309, [https://doi.org/10.1107/S2052520619001999]Published version of the article: [https://cer.ihtm.bg.ac.rs/handle/123456789/3521
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