2,042 research outputs found

    Thermal analysis of the ceramic material and evaluation of the bonding behavior of silicon-ceramic composite substrates

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    Abstract Thermal bonding of silicon and low-temperature cofired ceramics (LTCC) at sintering temperatures of 900 ° C represents currently the standard process in silicon-ceramic composite (SiCer) substrate fabrication. We analyse the thermal behavior of the LTCC using thermogravimetric analysis, differential scanning calorimetry and laser flash analysis. The thermal decomposition could be identified with a mass loss of 24% in the temperature range up to 1000 ° C what influences the thermal diffusivity with values from about 0.19 mm 2 s −1 before thermal treatment to below 0.10 mm 2 s −1 after thermal treatment. A specific heat capacity of 1 – 2 J (g · K) −1 is calculated. Further, an influence of low-temperature lamination of the LTCC seems to have an influence on the thermal behaviour. The sintering process was investigated with temperatures of 550 ° C, 730 ° C and 900 ° C, applied pressures of 12.2 kPa and 6.1 kPa and intermediate wetting layers of TiO 2 (normal deposition and oblique angle deposition). Optical observations, ultrasonic and scanning electron microscopy, and pull-tests are used to compare the properties of the sintered SiCer substrates. Whereas the sintering temperature has an obvious impact on the sintering behaviour of the LTCC, a direct conclusion of parameter variation on the bonding result was not observed

    187^{187}Re(\gamm,n) cross section close to and above the neutron threshold

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    The neutron capture cross section of the unstable nucleus 186^{186}Re is studied by investigating the inverse photodisintegration reaction 187^{187}Re(γ\gamma,n). The special interest of the {\it s}-process branching point 186^{186}Re is related to the question of possible {\it s}-process contributions to the abundance of the {\it r}-process chronometer nucleus ^{187}Re.Weusethephotoactivationtechniquetomeasurephotodisintegrationrates.Ourexperimentalresultsareingoodagreementwithtwodifferentstatisticalmodelcalculations.AlthoughthecrosssectionspredictedbybothmodelsfortheinversereactionRe. We use the photoactivation technique to measure photodisintegration rates. Our experimental results are in good agreement with two different statistical model calculations. Although the cross sections predicted by both models for the inverse reaction ^{186}Re(n,Re(n,\gamma)istoolowtoremovetheoverproductionof) is too low to remove the overproduction of ^{186}$Os; the two predicted neutron-capture cross sections differ by a factor of 2.4; this calls for future theoretical study.Comment: Phys. Rev. C, in pres

    Multi-Lens Array Full-Field X-ray Microscopy

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    X-ray full-field microscopy at laboratory sources for photon energies above 10 keV suffers from either long exposure times or low resolution. The photon flux is mainly limited by the objectives used, having a limited numerical aperture NA. We show that this can be overcome by making use of the cone-beam illumination of laboratory sources by imaging the same field of view (FoV) several times under slightly different angles using an array of X-ray lenses. Using this technique, the exposure time can be reduced drastically without any loss in terms of resolution. A proof-of-principle is given using an existing laboratory metal-jet source at the 9.25 keV Ga Kα-line and compared to a ray-tracing simulation of the setup

    A new photon recoil experiment: towards a determination of the fine structure constant

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    We report on progress towards a measurement of the fine structure constant to an accuracy of 5×10105\times 10^{-10} or better by measuring the ratio of the Planck constant to the mass of the cesium atom. Compared to similar experiments, ours is improved in three significant ways: (i) simultaneous conjugate interferometers, (ii) multi-photon Bragg diffraction between same internal states, and (iii) an about 1000 fold reduction of laser phase noise to -138 dBc/Hz. Combining that with a new method to simultaneously stabilize the phases of four frequencies, we achieve 0.2 mrad effective phase noise at the location of the atoms. In addition, we use active stabilization to suppress systematic effects due to beam misalignment.Comment: 12 pages, 9 figure

    Colour-emotion associations in individuals with red-green colour blindness

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    Colours and emotions are associated in languages and traditions. Some of us may convey sadness by saying feeling blue or by wearing black clothes at funerals. The first example is a conceptual experience of colour and the second example is an immediate perceptual experience of colour. To investigate whether one or the other type of experience more strongly drives colour-emotion associations, we tested 64 congenitally red-green colour-blind men and 66 non-colour-blind men. All participants associated 12 colours, presented as terms or patches, with 20 emotion concepts, and rated intensities of the associated emotions. We found that colour-blind and non-colour-blind men associated similar emotions with colours, irrespective of whether colours were conveyed via terms (r = .82) or patches (r = .80). The colour-emotion associations and the emotion intensities were not modulated by participants’ severity of colour blindness. Hinting at some additional, although minor, role of actual colour perception, the consistencies in associations for colour terms and patches were higher in non-colour-blind than colour-blind men. Together, these results suggest that colour-emotion associations in adults do not require immediate perceptual colour experiences, as conceptual experiences are sufficient

    Akzeptanz von Formeln - Vergleich zweier Erhebungen

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    Im Rahmen einer Untersuchung zum Formelverständnis bei Schülerinnen und Schülern werden in zwei Erhebungswellen unterschiedliche Jahrgangsbereiche miteinander verglichen. Die Ergebnisse sind in beiden Erhebungen ähnlich: Die Bedeutung von Formeln wird von Lernenden als hoch eingeschätzt, Formeln werden nicht durchweg abgelehnt

    Akzeptanz von Formeln - Vergleich zweier Erhebungen

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    Im Rahmen einer Untersuchung zum Formelverständnis bei Schülerinnen und Schülern werden in zwei Erhebungswellen unterschiedliche Jahrgangsbereiche miteinander verglichen. Die Ergebnisse sind in beiden Erhebungen ähnlich: Die Bedeutung von Formeln wird von Lernenden als hoch eingeschätzt, Formeln werden nicht durchweg abgelehnt

    Opioid-Induced Constipation and Bowel Dysfunction:A Clinical Guideline

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    OBJECTIVE:  To formulate timely evidence-based guidelines for the management of opioid-induced bowel dysfunction. SETTING:  Constipation is a major untoward effect of opioids. Increasing prescription of opioids has correlated to increased incidence of opioid-induced constipation. However, the inhibitory effects of opioids are not confined to the colon, but also affect higher segments of the gastrointestinal tract, leading to the coining of the term "opioid-induced bowel dysfunction." METHODS:  A literature search was conducted using Medline, EMBASE, and EMBASE Classic, and the Cochrane Central Register of Controlled Trials. Predefined search terms and inclusion/exclusion criteria were used to identify and categorize relevant papers. A series of statements were formulated and justified by a comment, then labeled with the degree of agreement and their level of evidence as judged by the Strength of Recommendation Taxonomy (SORT) system. RESULTS:  From a list of 10,832 potentially relevant studies, 33 citations were identified for review. Screening the reference lists of the pertinent papers identified additional publications. Current definitions, prevalence, and mechanism of opioid-induced bowel dysfunction were reviewed, and a treatment algorithm and statements regarding patient management were developed to provide guidance on clinical best practice in the management of patients with opioid-induced constipation and opioid-induced bowel dysfunction. CONCLUSIONS:  In recent years, more insight has been gained in the pathophysiology of this "entity"; new treatment approaches have been developed, but guidelines on clinical best practice are still lacking. Current knowledge is insufficient regarding management of the opioid side effects on the upper gastrointestinal tract, but recommendations can be derived from what we know at present

    The 2013 KIT IWSLT Speech-to-Text Systems for German and English

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    This paper describes our English Speech-to-Text (STT) systems for the 2013 IWSLT TED ASR track. The systems consist of multiple subsystems that are combinations of different front-ends, e.g. MVDR-MFCC based and lMel based ones, GMM and NN acoustic models and different phone sets. The outputs of the subsystems are combined via confusion network combination. Decoding is done in two stages, where the systems of the second stage are adapted in an unsupervised manner on the combination of the first stage outputs using VTLN, MLLR, and cMLLR
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