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  • 1
    Electronic Resource
    Electronic Resource
    Observation of size-dependent features in the photoluminescence of zinc oxide nanocrystallites by near-field ultraviolet spectroscopy (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 1444-1446 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical properties of single zinc oxide (ZnO) nanocrystallites were investigated at room temperature by extending the optical near-field technique to the UV region. Using a UV fiber probe with a subwavelength aperture, we performed spatially- and spectrally-resolved photoluminescence (PL) imaging of individual ZnO nanocrystallites with a spatial resolution of 55 nm. Furthermore, decreasing the spot size increased the intensities of higher-energy components of the PL spectrum due to the quantum size effect. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1453487
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  • 2
    Electronic Resource
    Electronic Resource
    Oxygen coordination of magnesium and calcium in binary magnesia and calcia metaphosphate glasses (1988)
    Springer
    Journal of materials science 23 (1988), S. 547-550 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An X-ray diffraction study has been carried out on binary phosphate and silicate glasses with MgO or CaO in equimolar composition. The structure of a 60 mol% CaO–40 mol% Al2O3 glass was also investigated for comparison. The electron radial distribution function was calculated by the usual Fourier transformation and interpretation of it was made in terms of pair functions. The number of oxygens around magnesium is evaluated to be four in both phosphate and silicate glasses. On the other hand, the number of oxygens which surround calcium appears to depend upon the component of network formers: namely, the oxygen coordination numbers around calcium are five in phosphate, six in silicate and four in aluminate glasses, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174683
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  • 3
    Electronic Resource
    Electronic Resource
    Impact response of periodontal tissues (1988)
    Springer
    Medical & biological engineering & computing 26 (1988), S. 260-266 
    Details
    ISSN: 1741-0444
    Keywords: Acceleration response ; Impact response ; Mechanical impedance ; Periodontal tissues ; Single degree-of-freedom model ; Tooth mobility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A new impact response method using a fracture of a pencil-lead to produce an excitation pulse is proposed. Impact excitations (rectangular pulse, triangular pulse and half-sine pulse) are strictly given in physical and mathematical definitions and complete solutions to the impact excitations are provided for Noyes' model of the human tooth. When a relatively long triangular pulse is applied to Noyes' model, which can express the physical characteristic of periodontal tissues, a sinusoidal damped vibration of a single degree-of-freedom model is approximately obtained. The acceleration response is characterised by the physical parameters (T, δ and Ao) and mechanical elements (m1, c1 and k) of which a single degree-of-freedom model is composed. By means of this method, the values of the parameters and elements in the cases of healthy maxillary, healthy mandibular and pathological mandibular incisors are obtained. The single degree-of-freedom model can express the high-frequency spectra of Noyes' model. The pathological tooth is characterised by a longer damped time constant and a larger acceleration maximum. This impact response method can effectively be applied to clinical diagnosis in view of the physical parameters and mechanical elements which have been derived.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02447078
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  • 4
    Electronic Resource
    Electronic Resource
    Application of mechanical mobility of periodontal tissues to tooth mobility examination (1989)
    Springer
    Medical & biological engineering & computing 27 (1989), S. 75-81 
    Details
    ISSN: 1741-0444
    Keywords: Automatic diagnosis ; Biomechanical properties ; Mechanical mobility ; MT figure ; Periodontium ; Tooth mobility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Tooth mobility examination is important in planning dental treatment, as it may give an indication of alveolar bone loss and the condition of the periodontal ligament. In clinical dental diagnosis a manual tooth mobility examination is useful. However, its determination of tooth mobility is subjective and depends on the skill and experience of the clinician. The authors have previously reported on a device for measuring the biomechanical properties of human periodontium using an impedance head. Using this device, the mechanical mobility of periodontium can be measured and the mechanical parameters of the periodontal physical model are obtained. Tooth mobility is defined objectively on the basis of discriminant scores of mechanical parameters, and a mobility triangle (MT) figure is drawn as a record for visual interpretation. The paper describes the validation of the mechanical mobility measurements and their interpretation using mobility parameters and a personal computer to produce a mobility triangle figure. The method is compared favourably with clinical mobility measurement. The relationship of the model to underlying pathology is tested by measurements performed on various tooth model systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442173
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  • 5
    Electronic Resource
    Electronic Resource
    A study on the ductile fracture of Al-alloys 7075 and 2017 (1990)
    Springer
    International journal of fracture 42 (1990), S. 389-404 
    Details
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Résumé On étudie expérimentalement le mécanisme de la rupture ductile sur des échantillons d'alliages d'aluminium 7075-T6 et 2017-T4. Les essais sont effectués sur des éprouvettes ICT, analysées par émission acoustique et par examen topographique de la surface de rupture, le processus de la rupture étant étudié en temps réel. Trois types d'émissions acoustiques ressortent d'une analyse de fréquences. Le détail de la nucléation de cavités, puis de la croissance et de la coalescence des cavités en une fissure, puis du processus de la propagation de la fissure apparaissent clairement grâce à l'examen topographique. Une émission acoustique à forte énergie avec des composantes à basse fréquence correspond à une coalescence à grande vitesse de fissures et de cavités dans le voisinage, et cette énergie est en relation avec la surface de propagation de la fissure.
    Notes: Abstract The mechanism of the ductile fracture is studied experimentally for the Al-alloys 7075-T6 and 2017-T4 specimen. The experiments are conducted for the 1CT specimen and they are analyzed by using the acoustic emission and FRASTA (Fracture Surface Topographic Analysis) technique and the process of the fracture is investigated in real time. By the frequency analysis there are 3 kinds of AE patterns of the AE occurrence. By using the FRASTA technique, the details of voids nucleation and growth and the coalescence of voids and crack and the crack propagation process is clarified visually. AE with small amplitude corresponds to the cracking and decohesion of the inclusions and the AE of the large energy with eminent low cycle components corresponds to the high speed coalescence of cracks and voids nearby and this energy corresponds to the propagation area of the crack.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01185959
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