975 research outputs found

    Surface wave control for large arrays of microwave kinetic inductance detectors

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    Large ultra-sensitive detector arrays are needed for present and future observatories for far infra-red, submillimeter wave (THz), and millimeter wave astronomy. With increasing array size, it is increasingly important to control stray radiation inside the detector chips themselves, the surface wave. We demonstrate this effect with focal plane arrays of 880 lens-antenna coupled Microwave Kinetic Inductance Detectors (MKIDs). Presented here are near field measurements of the MKID optical response versus the position on the array of a reimaged optical source. We demonstrate that the optical response of a detector in these arrays saturates off-pixel at the 30\sim-30 dB level compared to the peak pixel response. The result is that the power detected from a point source at the pixel position is almost identical to the stray response integrated over the chip area. With such a contribution, it would be impossible to measure extended sources, while the point source sensitivity is degraded due to an increase of the stray loading. However, we show that by incorporating an on-chip stray light absorber, the surface wave contribution is reduced by a factor >>10. With the on-chip stray light absorber the point source response is close to simulations down to the 35\sim-35 dB level, the simulation based on an ideal Gaussian illumination of the optics. In addition, as a crosscheck we show that the extended source response of a single pixel in the array with the absorbing grid is in agreement with the integral of the point source measurements.Comment: accepted for publication in IEEE Transactions on Terahertz Science and Technolog

    Eliminating stray radiation inside large area imaging arrays

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    With increasing array size, it is increasingly important to control stray radiation inside the detector chips themselves. We demonstrate this effect with focal plane arrays of absorber coupled Lumped Element microwave Kinetic Inductance Detectors (LEKIDs) and lens-antenna coupled distributed quarter wavelength Microwave Kinetic Inductance Detectors (MKIDs). In these arrays the response from a point source at the pixel position is at a similar level to the stray response integrated over the entire chip area. For the antenna coupled arrays, we show that this effect can be suppressed by incorporating an on-chip stray light absorber. A similar method should be possible with the LEKID array, especially when they are lens coupled.Comment: arXiv admin note: substantial text overlap with arXiv:1707.0214

    C21orf57 is a human homologue of bacterial YbeY proteins

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    The product of the human C21orf57 (huYBEY) gene is predicted to be a homologue of the highly conserved YbeY proteins found in nearly all bacteria. We show that, like its bacterial and chloroplast counterparts, the HuYbeY protein is an RNase and that it retains sufficient function in common with bacterial YbeY proteins to partially suppress numerous aspects of the complex phenotype of an Escherichia coli ΔybeY mutant. Expression of HuYbeY in Saccharomyces cerevisiae, which lacks a YbeY homologue, results in a severe growth phenotype. This observation suggests that the function of HuYbeY in human cells is likely regulated through specific interactions with partner proteins similarly to the way YbeY is regulated in bacteria.National Institutes of Health (U.S.) (Grant GM31010)National Institutes of Health (U.S.) (Grant GM17151

    DESIGN AND IMPLEMENTATION OF AUTOMATEDCLEANING OF CEILING FAN

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    The main objective of the project is to reduce the human effort and sluggishness of human when the operation is in large scale and to avoid the risk in case of any accidents. The proposed system that is portable and ensure regular cleaning of the ceiling fan using some mechanical setup such as scissor lift, lead screw whose movements are controlled by microcontroller which controls a pneumatic control and some cleaning mechanisms

    Solid Electrolytes for High-Temperature Stable Batteries and Supercapacitors /

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    Reports of recent fire accidents in the electronics and electric vehicles (EVs) industries show that thermal runaway (TR) reactions are a key consideration for the industry. Utilization of solid electrolytes (SEs) could be an important solution in to the TR issues connected to exothermic electrochemical reactions. Data on the thermal stability of modern SEs, ionic transport mechanisms, kinetics, thermal models, recent advances, challenges, and future prospects are presented in this review. Ceramic polymer nanocomposites are the most appropriate SEs for high‐temperature stable batteries (in the range of 80–200 °C). Hydrogels and ionogels can be employed as stable, flexible, and mechanically durable SEs for antifreeze (up to –50 °C) and high‐temperature (up to 200 °C) applications in supercapacitors. Besides the thermal safety features, SEs can also prolong the lifecycle of energy storage devices in next‐generation EVs, space devices, aviation gadgets, defence tools, and mobile electronics.ye

    Photoelectrochemical Conversion of Carbon Dioxide (CO2) into Fuels and Value-Added Products /

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    The conversion of carbon dioxide (CO2) into fuels and value-added products is one of the most significant inventions to address the global warming and energy needs. Photoelectrochemical (PEC) CO2 conversion can be considered as an artificial photosynthesis technique that produces formate, formaldehyde, formic acid, methane, methanol,ethanol, etc. Recent advances in electrode materials, mechanisms, kinetics, thermodynamics, and reactor designs of PEC CO2 conversion have been comprehensively reviewed in this article. The adsorption and activation of CO2/intermediates at the electrode surface are the key steps for improving the kinetics of CO2 conversion. PEC efficiency could be upgraded through the utilization of 2D/3D materials, plasmonic metals, carbon-based catalysts, porous nanostructures, metal−organic frameworks, molecular catalysts, and biological molecules. The defect engineered (by cation/anion vacancy, crystal distortion, pits, and creation of oxygen vacancies) 2D/3D materials, Z-scheme heterojunctions, bioelectrodes, and tandem photovoltaic−PEC reactors are suitable options to enhance the efficiency at low external bias.ye

    Mining Integrated Sequential Patterns From Multiple Databases

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    Existing work on multiple databases (MDBs) sequential pattern mining cannot mine frequent sequences to answer exact and historical queries from MDBs having different table structures. This article proposes the transaction id frequent sequence pattern (TidFSeq) algorithm to handle the difficult problem of mining frequent sequences from diverse MDBs. The TidFSeq algorithm transforms candidate 1-sequences to get transaction subsequences where candidate 1-sequences occurred as (1-sequence, itssubsequenceidlist) tuple or (1-sequence, position id list). Subsequent frequent i-sequences are computed using the counts of the sequence ids in each candidate i-sequence position id list tuples. An extended version of the general sequential pattern (GSP)-like candidate generates and a frequency count approach is used for computing supports of itemset (I-step) and separate (S-step) sequences without repeated database scans but with transaction ids. Generated patterns answer complex queries from MDBs. The TidFSeq algorithm has a faster processing time than existing algorithms
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