1,929 research outputs found

    Very low scale Coleman-Weinberg inflation with non-minimal coupling

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    We study viable small-field Coleman-Weinberg (CW) inflation models with the help of non-minimal coupling to gravity. The simplest small-field CW inflation model (with a low-scale potential minimum) is incompatible with the cosmological constraint on the scalar spectral index. However, there are possibilities to make the model realistic. First, we revisit the CW inflation model supplemented with a linear potential term. We next consider the CW inflation model with a logarithmic non-minimal coupling and illustrate that the model can open a new viable parameter space that includes the model with a linear potential term. We also show parameter spaces where the Hubble scale during the inflation can be as small as 10410^{-4} GeV, 11 GeV, 10410^4 GeV, and 10810^8 GeV for the number of ee-folds of 40, 45, 5040,~45,~50, and 5555, respectively, with other cosmological constraints being satisfied.Comment: 14 pages, 9 figures, published versio

    Influence of Diamond Seed Attachment Processing on Diamond Films Synthesized on Tungsten Carbide Substrate by Flame Combustion

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    The flame combustion method enables the synthesis of diamonds via acetylene-oxygen gas flame combustion in ambient air. Tungsten carbide (WC) has recently been utilized as a cutting tool in the machining industry and in dental machining applications. To obtain high-quality diamond films and achieve good adhesion on a WC substrate, diamond films are synthesized on a WC substrate by the flame combustion method. However, the surface roughness of most of the diamond films synthesized by this method increased, and it was necessary to reduce this roughness. Considering the roughness accuracy of the workpiece surface during cutting, and the performance of the cutting tool, a smaller surface roughness of the diamond films synthesized is desirable. In this study, to reduce surface roughness, the amount of diamond paste with diamond seed particles as generation nuclei was carefully varied for diamond seed attachment processing of diamond films. When diamond films were synthesized on the WC substrate surface via the flame combustion, the amount of diamond paste with diamond seed particles affected the surface morphology and surface roughness of the synthesized diamond films. Furthermore, to investigate the reason for this result, generation of nuclei on the substrate in the initial stages of synthesis and diamond seed particles on the substrate surface after the seeding treatment were observed by scanning electron microscopy. The effect of diamond seed attachment processing on the diamond films synthesized by flame combustion was studied. The relationship between the surface roughness, number of diamond generation nuclei on the substrate in the initial stages of synthesis, number of diamond particles on the substrate after the diamond seeding process, and amount of diamond paste were confirmed

    "Fuzzy front end" practices in innovating Japanese companies

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    In this paper, we report on the results of a large-scale study about typical front-end-related innovation practices in 553 Japanese mechanical and electrical engineering companies. We explore typical activities concerning the generation and assessment of new product ideas, the reduction of technological as well as market uncertainty and front end planning. Finally, we report on differences between successful and unsuccessful companies. Our study confirms earlier findings about the frequent use of creativity techniques in Japan during the process of idea generation. We also find companies to intensively involve upper management and customers into NPD projects. While integrating upper management is of vital importance for assessing new product ideas, integrating customers and users is primarily used to developing product ideas and concepts. We further find evidence that successful companies integrate their customers more frequently in the process of developing and assessing new product ideas than non successful companies. In addition, the former integrate customer requirements into their product definitions more often and also translate these requirements into technical specifications more frequently than non-successful companies. Finally, successful companies more often systematically plan a project prior to its start than unsuccessful ones. --New product development,Japanese firms,planning,success innovation

    Guided Lock of a Suspended Optical Cavity Enhanced by a Higher Order Extrapolation

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    Lock acquisition of a suspended optical cavity can be a highly stochastic process and is therefore nontrivial. Guided lock is a method to make lock acquisition less stochastic by decelerating the motion of the cavity length based on an extrapolation of the motion from an instantaneous velocity measurement. We propose an improved scheme which is less susceptible to seismic disturbances by incorporating the acceleration as a higher order correction in the extrapolation. We implemented the new scheme in a 300-m suspended Fabry-Perot cavity and improved the success rate of lock acquisition by a factor of 30
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