14,363 research outputs found

    A map of the non-thermal WIMP

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    We study the effect of the elastic scattering on the non-thermal WIMP, which is produced by direct decay of heavy particles at the end of reheating. The non-thermal WIMP becomes important when the reheating temperature is well below the freeze-out temperature. Usually, two limiting cases have been considered. One is that the produced high energetic dark matter particles are quickly thermalized due to the elastic scattering with background radiations. The corresponding relic abundance is determined by the thermally averaged annihilation cross-section at the reheating temperature. The other one is that the initial abundance is too small for the dark matter to annihilate so that the final relic is determined by the initial amount itself. We study the regions between these two limits, and show that the relic density depends not only on the annihilation rate, but also on the elastic scattering rate. Especially, the relic abundance of the p-wave annihilating dark matter crucially relies on the elastic scattering rate because the annihilation cross-section is sensitive to the dark matter velocity. We categorize the parameter space into several regions where each region has distinctive mechanism for determining the relic abundance of the dark matter at the present Universe. The consequence on the (in)direct detection is also studied.Comment: 9 pages, 5 figures; v2: discussion improved, matches version published in PL

    Designing Urban Media Storytelling through Greimas ’ Narrative Model

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    This article attempts to establish an urban media storytelling model based on Greimas’ narrative model. Greimas ’ narrative model is distinguished into Narrative Schema model and Actantial model. Of course, other contents that reproduced through urban media can also establish storytelling strategies using these. Moreover, it can also be utilized in establishing a storytelling that applies to the entire space called “city. ” To be more specific, it is a process that receives information and entertainment based on the city, explores the city and ultimately recognizes the city image. This writing suggest such storytelling design linked with a narrative schema and actantial model

    Accelerated Life Testing to Predict Service Life and Reliability for an Appliance Door Hinge

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    Appliance manufacturers have traditionally performed physical testing using prototypes to assess reliability and service integrity of new product designs. However, for white goods where service lives are measured in years or decades, the use of endurance testing to analyze long time reliability is uneconomical. As accelerated life testing (ALT) is more efficient and less costly than traditional reliability testing, the methodology is finding increased usage by appliance manufacturers. In the present study, a simulation-based ALT approach was used to predict the service life of a polyacetal hinge cam from a consumer refrigerator. A predictive life stress model based on cumulative surface wear under accelerated stress conditions was developed and used to predict time to failure under consumer use. Results show that the life stress model demonstrated good agreement with performance testing data and reasonably predicts hinge life

    The Impact of Distance on the Accuracy of Luminance Measurement

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    AbstractMany researchers want to reduce the severe luminance difference caused by artificial lights or natural lighting and when luminance is highly uniform. This paper focused on the correlation between measured luminance and the distance of measurement from the light source. For this task, two types of luminance measuring methods were adopted. Namely, High Dynamic Range (HDR) image processing and CS-100 instrument for measuring surface luminance and point luminance respectively. The results indicate that there was a 3% decrease in measured luminance as the distance from the light source was increased by 1m

    Sonographic Detection of Intrathyroidal Branchial Cleft Cyst: A Case Report

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    We report here on an extremely rare case of an intrathyroidal branchial cleft cyst. Intrathyroidal branchial cleft cyst is rare disease entity and it has nonspecific findings on sonography, so the diagnosis of the lesion is very difficult. However, during aspiration, if pus-like materials are aspirated from a thyroid cyst, we should consider the possibility of intrathyroidal branchial cleft cyst in the differential diagnosis

    Molecular identification of Reesa vespulae (Milliron) (Coleoptera: Dermestidae), a newly recorded species from Korea

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    AbstractA museum pest belonging to the family Dermestidae was found in the Museum of Sunchon National University, Sunchon, Korea and identified using its morphological characteristics and a DNA-based analysis of the mitochondrial cytochrome c oxidase I (COI) gene. This marks the first recorded appearance of this pest, which is identified as Reesa vespulae (Milliron), in the Korean Peninsula. We provide the details of the morphological diagnosis with the habitus of its adult and larva and its COI barcode data, and introduce historical data about its invasion around the world

    Effect of Porosity in Activated Carbon Supports for Silicon-Based Lithium-Ion Batteries (LIBs)

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    Activated carbon supports for Si deposition with different porosities were prepared, and the effect of porosity on the electrochemical characteristics was investigated. The porosity of the support is a key parameter affecting the Si deposition mechanism and the stability of the electrode. In the Si deposition mechanism, as the porosity of activated carbon increases, the effect of particle size reduction due to the uniform dispersion of Si was confirmed. This implies that the porosity of activated carbon can affect the rate performance. However, excessively high porosity reduced the contact area between Si and activated carbon, resulting in poor electrode stability. Therefore, controlling the porosity of activated carbon is essential to improving the electrochemical characteristics
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