312,444 research outputs found

    Evaluation of touch trigger probe measurement uncertainty using FEA

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    Evaluation of measurement uncertainty is an essential subject in dimensional measurement. It has also become a dominant issue in coordinate measuring machine (CMM) even though its machine performance has been well accepted by many users. CMM probes, especially touch trigger probes which are commonly used, have been acknowledged as a key error source, largely due to pre-travel variations. The probe errors result in large measurement uncertainty in CMM measurement. Various methods have been introduced to estimate measurement uncertainty, but they tend to be time consuming and necessarily require a large amount of experimental data for analyzing the uncertainty. This paper presents the method of evaluation of CMM probe uncertainty using FEA modeling. It is started with the investigation of the behavior of probe by recording stylus displacement with vary triggering force. Then, those displacement results will be analyzed with sensitivity analysis technique to estimate the uncertainty of recorded results

    Photons from the Color Glass Condensate in p+A collisions

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    We report on a first NLO computation of photon production in p+A collisions at collider energies within the Color Glass Condensate framework, significantly extending previous LO results. At central rapidites, our result is the dominant contribution and probes multi-gluon correlators in nuclei. At high photon momenta, the result is directly sensitive to the nuclear gluon distribution. The NLO result contains two processes, the annihilation process and the process with qqˉq\bar{q} pair and a photon in the final state. We provide a numerical evaluation of the photon spectrum from the annihilation process.Comment: Hard Probes 2016 proceedings contribution, Sep. 23-27, Wuhan, China. 4 pages, 3 figure

    Bayesian estimation of one-parameter qubit gates

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    We address estimation of one-parameter unitary gates for qubit systems and seek for optimal probes and measurements. Single- and two-qubit probes are analyzed in details focusing on precision and stability of the estimation procedure. Bayesian inference is employed and compared with the ultimate quantum limits to precision, taking into account the biased nature of Bayes estimator in the non asymptotic regime. Besides, through the evaluation of the asymptotic a posteriori distribution for the gate parameter and the comparison with the results of Monte Carlo simulated experiments, we show that asymptotic optimality of Bayes estimator is actually achieved after a limited number of runs. The robustness of the estimation procedure against fluctuations of the measurement settings is investigated and the use of entanglement to improve the overall stability of the estimation scheme is also analyzed in some details.Comment: 10 pages, 5 figure

    Recent progress in the synthesis of six-membered aminocyclitols (2008-2017)

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    Aminocyclitols are of interest as glucosidase inhibitors, as probes for the study of pseudoglycosyltransferases, and as potential therapeutics for the treatment of Gaucher’s disease. The synthesis of these targets was reviewed in early 2008, and the aim of this review is to cover material relevant to the synthesis of aminocyclitols since that time. While not a focus of this review, biological evaluation of compounds will be presented where it is recorded in the literature

    Technique for temperature compensation of eddy-current proximity probes

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    Eddy-current proximity probes are used in turbomachinery evaluation testing and operation to measure distances, primarily vibration, deflection, or displacment of shafts, bearings and seals. Measurements of steady-state conditions made with standard eddy-current proximity probes are susceptible to error caused by temperature variations during normal operation of the component under investigation. Errors resulting from temperature effects for the specific probes used in this study were approximately 1.016 x 10 to the -3 mm/deg C over the temperature range of -252 to 100 C. This report examines temperature caused changes on the eddy-current proximity probe measurement system, establishes their origin, and discusses what may be done to minimize their effect on the output signal. In addition, recommendations are made for the installation and operation of the electronic components associated with an eddy-current proximity probe. Several techniques are described that provide active on-line error compensation for over 95 percent of the temperature effects
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