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  • 1
    Electronic Resource
    Electronic Resource
    Characterization of intrinsic a-Si:H in p-i-n devices by capacitance measurements: Theory and experiments (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 3534-3541 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A technique has been developed for characterizing the intrinsic layer in a-Si:H p-i-n structures. The method is based on the measurement of the differential capacitance under forward bias, i.e., with injection of free carriers in the intrinsic layer. In these conditions, capacitance is extremely dependent on charges trapped in the band-gap defects. Measurements were performed on several p-i-n samples, in a wide range of frequencies and voltages. All the samples showed the same trend: Capacitance diminished with increasing signal frequency and increased with forward applied voltage. An analytical model explains the obtained behavior. In particular, the model shows that the band-tail contribution to capacitance decreases slowly with frequency, while deeper defects are effective only below 100 Hz. At higher frequencies, trapping phenomena play a lesser and lesser role in the measurement while depletion charge becomes relevant and the measured capacitance tends to its asymptotic junction value (i.e., the ratio dielectric constant/thickness of the p-i-n). The model predicts a high sensitivity to defect distribution in the gap of the intrinsic layer, thus allowing an effective characterization of the semiconductor material as is in the actual device. Up to 1017 cm−3 defects have been detected via the capacitance technique, presumably located in the portion of the intrinsic layer closest to the p/i interface. The origin of such a large amount of defects can be related to the presence of inhomogeneities due to the interfaces in the p-i-n device. These defects behave as free-carrier traps, and do not affect the recombination mechanism. A picture of the electronic defect distribution in the device material is finally proposed which accounts for both midgap neutral dangling bonds and shallower charged defects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357435
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  • 2
    Electronic Resource
    Electronic Resource
    Contactless Characterization of Semiconductors Using Laser-Induced Surface Photo-Charge Voltage Measurements (1994)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 173-174 (Sept. 1994), p. 221-226 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/00/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.173-174.221.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Analysis of amino acids as DABS-derivatives with a sensitivity to the femtomole level using RP-HPLC narrow-bore columns (1992)
    Springer
    Amino acids 3 (1992), S. 303-309 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Reversed-phase high performance liquid chromatography ; DABS-Amino acids ; Narrow-bore columns ; Amino and imino acid analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this paper we report the complete separation of amino acids as DABS-derivatives using a 3µm Supelcosil LC-18 (25 cm × 2.1 mm I.D.) narrowbore column. The system described makes it possible to perform the analysis of DABS-amino acids with a sensitivity to the femtomole level. We have also studied the conditions necessary for using the narrow-bore columns for routine analysis, paying particular attention to the problem of providing adequate protection for the analytical column. We have found it very suitable to use a (2 cm × 2.1 mm I.D.) guard column filled with a 40µm Pelliguard LC-18, pellicular packing resin, without affecting the complete resolution of the DABS-amino acids. Comparing the results obtained using conventional HPLC columns (3–5µm Supelcosil LC-18) of different lengths (15 and 25 cm × 4.6 mm I.D.) with those obtainable with the narrow-bore columns used in this work, it is possible to achieve a much greater sensitivity using the narrow-bore columns. In short, using the appropriate guard column and the “standard” HPLC apparatus used, the narrow-bore columns are very useful for routine analyses of DABS-amino acids with a sensitivity at the femtomole level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00806005
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  • 4
    Electronic Resource
    Electronic Resource
    Disseminated tuberculosis of the central nervous system responsive to rifabutin (1990)
    Springer
    Neurological sciences 11 (1990), S. 163-169 
    Details
    ISSN: 1590-3478
    Keywords: Tuberculosis ; magnetic resonance imaging ; rifabutin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommario I tubercolomi cerebrali multipli sono assai raramente osservati; in letteratura sono documentati circa trenta casi. Descriviamo il caso di un giovane uomo che giunge all'osservazione con una storia di otto mesi di cefalea, febbricola, ascesso della tibio-tarsica sinistra. Operato l'ascesso, si riscontra mycobacterium tubercolosis nel materiale asportato. La radiografia del torace evidenzia disseminazione miliariforme ad entrambi i polmoni. TAC ed RMN cerebrali documentano numerosissimi piccoli noduli coinvolgenti specialmente la fosse posteriore. Nonostante instaurazione di terapia antimicobatterica classica, compare emisindrome piramidale destra con ipertensione endocranica. Introducendo Rifabutina si osserva rapido miglioramento della situazione. Dopo un anno di terapia il paziente è il buone condizioni; le lesioni cerebrali e polmonari scomparse. L'interesse del caso è determinato dalla pluricentricità dei processi TBC in paziente non-immunodepresso, dalla disseminazione tubercolare al nevrasse senza interessamento meningeo e dalla resistenza ai classici antimicobatterici, con pronta risposta alla Rifabutina.
    Notes: Abstract Multiple cerebral tuberculomas are now very rare. We report the case of a young man with an 8-month history of headache, febricula and abscess of the left tibiotarsal joint, which was found to contain mycobacterium tuberculosis. Chest X-rays revealed miliariform dissemination to both lungs while CT and MR brain scans revealed numerous small nodules, especially in the posterior cranial fossa. Despite anti-tuberculosis therapy the patient developed a right pyramidal hemisyndrome and intracranial hypertension. The inclusion of rifabutin in the treatment schedule was followed by rapid improvement and a year later the patient was in good health and free from cerebral and pulmonary lesions. The interest of the case lies in the multiplicity of sites of the TB process in a non immunodepressed patient, the dissemination to the CNS without meningeal involvement, the resistance to standard antimycobacterials and the swift response to rifabutin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02335560
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Shape optimization of an elastic thin shell under various criteria (1991)
    Springer
    Structural and multidisciplinary optimization 3 (1991), S. 7-21 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The aim of this study is to propose a methodology for optimizing the shape (middle surface and thickness) of an elastic general thin shell (i) under different criteria: minimization of the weight, of the stresses, of the strain energy; (ii) with or without constraints: if any, these can be bounds on some displacements, on some stresses. This is a common problem in real life, the engineer has to construct structures which have the best mechanical behaviour and the best price; the price is often proportional to the weight of the structure. In this paper only the general continuous formulation of the problems is considered. From this strong basis a corresponding discrete formulation and some industrial applications will subsequently be developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01743485
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    Paper (German National Licenses)
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