Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles: DFG German National Licenses  (9)
  • 41.80 Dd  (3)
  • 42.55  (2)
  • Chest radiography  (2)
  • Radiation exposure  (2)
Source
  • Articles: DFG German National Licenses  (9)
Material
Years
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Near infrared lasing transitions in Ar, Kr, and Xe atoms pumped by a coaxial e-beam (1988)
    Springer
    Applied physics 47 (1988), S. 187-190 
    Details
    ISSN: 1432-0649
    Keywords: 42.55 FN ; 41.80 Dd
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Optimizations of gas composition and input energy were performed for gas mixtures containing a buffer gas and either Ar, Kr or Xe as the lasing gas. The total gas pressure was varied between 1 and 14 bar and the input energy from 0.03 to 0.7 J/cm3. The excitation source was a small coaxial electron beam with a pumping length of 20 cm and a pulse length of 30 ns (FWHM). From an active volume of 13.3 cm3 a maximum output energy of 12 mJ was obtained from a gas mixture containing 0.3% Xe in Ar at a total gas pressure of 10 bar. The intrinsic efficiency was 0.9%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00684086
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Intrinsic efficiency and critical power deposition in the e-beam sustained Ar:Xe Laser (1991)
    Springer
    Applied physics 52 (1991), S. 277-280 
    Details
    ISSN: 1432-0649
    Keywords: 42.55 Fn ; 41.80 Dd ; 52.80 Tn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Experimental investigations on an e-beam sustained near infrared Ar:Xe laser have been carried out to determine the intrinsic efficiency at optimized conditions. A parametric study at different sustainer currents reveals a maximum output energy depending on current density. Up to 8 bar the optimized laser output power per unit volume increases linearly with 1.1MW/1 bar. Intrinsic efficiencies of up to about 8% are feasible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325405
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Spectral line competition in a coaxial electron-beam-pumped high pressure Ar/Xe laser (1991)
    Springer
    Applied physics 52 (1991), S. 336-340 
    Details
    ISSN: 1432-0649
    Keywords: 34.80 D ; 41.80 Dd ; 42.55 F
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In order to study the kinetic mechanism of the e-beam pumped Ar/Xe laser, the temporal profiles of individual laser lines during multiline oscillation have been measured as a function of power deposition (1–12MW/cm3) and gas laser pressure (2–14 bar) using a short pulse (30 ns) coaxial electron beam as excitation source. It was found that the optimum output energy at each pressure was obtained at the same specific power deposition. Strong line competition has been observed between the 2.65 and 1.73 μm transitions. In order to explain our results we suggest that besides electron collision mixing (ECM) between the 5d and 6p levels of Xe, there is also a redistribution between all 6p levels which strongly favours the lower levels at higher pumping densities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325492
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Spectral investigation of cw rf-pumped atomic Xe laser with a slab geometry (1996)
    Springer
    Applied physics 62 (1996), S. 11-14 
    Details
    ISSN: 1432-0649
    Keywords: 42.55 ; 42.60 ; 52.90
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A radiofrequency excited atomic Xe slab laser with an active volume of 2 × 10 × 300 mm3 using a quartz envelope containing the laser-gas mixture shows a stable cw performance with an output power of almost 1 W. The free-running system oscillates, depending on gas composition and density, on several lines between 1.73 and 3.51 μm. Line competition phenomena are observed. Single-line oscillation yields more than 500 mW.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081241
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Theoretical and experimental investigation of a waveguide CO2 laser with radio-frequency excitation (1996)
    Springer
    Applied physics 62 (1996), S. 113-127 
    Details
    ISSN: 1432-0649
    Keywords: 42.55 ; 52.00 ; 34.80 ; 52.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A comprehensive experimental and theoretical study of the optimization of a continuous-wave radiofrequency (rf) excited CO2 waveguide laser is presented. The numerical simulation includes the modelling of the gas-discharge plasma parameters like the plasma impedance and energy deposition, the laser kinetics and finally the influence of the resonator feedback on the lasing process. Along with this theoretical study, an extensive experimental research program enabled us to optimize the laser performance of the CO2 waveguide laser. As a result, a total output power of 42 W and a specific output power of 1.1 W/cm were obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Radiation exposure in patients undergoing endoscopic retrograde cholangiopancreatography and endoscopic papillotomy (1978)
    Springer
    Abdominal imaging 3 (1978), S. 353-355 
    Details
    ISSN: 1432-0509
    Keywords: Radiation exposure ; Endoscopic retrograde cholangiopancreatography ; Endoscopic papillotomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Radiation exposure was studied in 327 patients undergoing endoscopic retrograde cholangiopancreatography, or endoscopic papillotomy taking into account fluoroscopy time and incident area exposure. The mean fluoroscopy time was 238±152 seconds and the incident area exposure 3,730±2,790 R×cm2. These results were compared with standard exposures in upper GI series and colon examinations as found in the literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01887091
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Bronchiolitis obliterans with organizing pneumonia. Clinical features, pathology and imaging findings (1996)
    Springer
    Der Radiologe 36 (1996), S. 560-566 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Bronchiolitis obliterans mit organisierender Pneumonie ; BOOP ; Thoraxübersichtsaufnahme ; Computertomographie ; Key words Bronchiolitis obliterans with organizing pneumonia (BOOP) ; Chest radiography ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Bronchiolitis obliterans with organizing pneumonia (BOOP) is a clinicopathological syndrome of unknown etiology. Histopathologically, it is characterized by plugs of fibroplastic connective tissue within respiratory bronchioles, mononuclear cell infiltrates in parenchyma adjacent to the affected bronchioles and foam cells within alveolar airspaces. The disease usually presents as a subacute illness with complete resolution. A subset of BOOP, however, is associated with a fulminant course and a high lethality due to respiratory failure. Early diagnosis and therapy are mandatory. Chest radiography, computed tomography (CT), bronchoalveolar lavage (BAL) and open lung biopsy are the primary diagnostic techniques. Radiographically, BOOP is characterized by patchy areas of consolidation that are usually bilateral, peripheral and often migratory. In some cases small, round opacities may be observed as the only abnormality. CT can show the pattern of ground glass opacities, areas of airspace consolidation and small, round opacities, while considerable fibrotic change is usually not seen. A reticular roentgenographic pattern, fibrotic changes mainly in subpleural location at CT, lack of lymphocytosis in BAL fluid and histological features of usual interstitial pneumonitis and BOOP in biopsy specimens are all considered risk factors for a fatal outcome.
    Notes: Zusammenfassung Die Bronchiolitis obliterans mit organisierender Pneumonie (BOOP) ist eine klinisch-pathologisch definierte Lungenerkrankung oft ungeklärter Ätiologie, histologisch gekennzeichnet durch proliferierendes Granulationsgewebe in den respiratorischen Bronchiolen sowie interstitielle mononukleäre Zellinfiltrate und Schaumzellen in den Alveolen. Meist nimmt sie einen blanden Verlauf und hat eine günstige Prognose. Doch auch fulminante Verläufe mit letalem Ausgang sind beschrieben. Eine frühzeitige Diagnosestellung und Therapieeinleitung bestimmen wesentlich den Behandlungserfolg. Eckpfeiler der Diagnostik sind Übersichtsaufnahme und Computertomographie des Thorax, bronchoalveoläre Lavage (BAL) und Lungenbiopsie. Die Thoraxübersichtsaufnahme zeigt typischerweise bipulmonale, periphere, kleinfleckig-konfluierende Verschattungen, oft mit einer Migrationstendenz. Computertomographisch finden sich kleinfleckige, milchglasartige oder konsolidierende Verschattungen jeweils allein oder in Kombination, ohne daß wesentliche fibrotische Veränderungen nachweisbar sind. Ein retikuläres Verschattungsmuster in der Thoraxübersichtsaufnahme, subpleurale Fibroseherde in der CT, fehlende Lymphozytose in der BAL und der histologische Nachweis einer intraluminalen und interstitiellen Entzündungskomponente mit unterschiedlichen Fibrosestadien im Sinne einer kryptogenen fibrosierenden Alveolitis gelten als prädiktive Faktoren für einen ungünstigen Verlauf der BOOP. Bei antibiotikarefraktären Infiltraten sollte an die Verdachtsdiagnose einer BOOP gedacht werden und gegebenenfalls eine histologische Untersuchung erfolgen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050111
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Bildgebende Diagnostik bei Bronchiektasen Stellenwert von CT und HRCT (1996)
    Springer
    Der Radiologe 36 (1996), S. 550-559 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Bronchiektasen ; Thoraxübersichtsaufnahme ; Bronchographie ; Computertomographie ; HRCT ; Key words Bronchiectasis ; Chest radiography ; Bronchography ; Computed tomography ; HRCT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Various diseases can cause bronchiectasis as a result of inflammatory bronchial wall damage. The diagnosis is based on imaging techniques, which are also required to assess the extent and localization of dilated bronchi and possible causes. Chest radiography only occasionally allows the diagnosis of bronchiectasis (Fig. 2) and is usually not a sufficient basis for therapeutic decisions (Fig. 1 a), but it is important for follow-up studies. Bronchography (Fig. 1 b) was considered the diagnostic procedure of choice in suspected bronchiectasis for decades. Being an invasive procedure, it has recently been almost completely replaced by computed tomography (CT), which can also demonstrate associated pulmonary abnormalities (Fig. 6) in addition to visualizing the bronchi. CT diagnosis of bronchiectasis is based on the demonstration of bronchial dilatation relative to the adjacent pulmonary artery (Figs. 4, 5, 7–9), lack of bronchial tapering (Figs. 3, 4, 10) and visualization of bronchi in the lung periphery (Figs. 3, 5, 8, 10). In suspected bronchiectasis high-resolution scans should be obtained during inspiration. Contiguous, thicker slices or scans taken during expiration may be required in particular cases.
    Notes: Zusammenfassung Bronchiektasen entstehen im Rahmen unterschiedlicher Erkrankungen durch inflammatorische Schädigung der Bronchialwand. Sie werden im wesentlichen mittels bildgebender Verfahren diagnostiziert, die auch erforderlich sind, um Ausmaß, Lokalisation, mögliche Ursachen und Begleitveränderungen darzustellen. Die Thoraxübersichtsaufnahme erlaubt nur in wenigen Fällen eine eindeutige Diagnose und reicht in der Regel zur Therapieplanung nicht aus. In der Verlaufskontrolle von Komplikationen besitzt sie dagegen einen hohen Stellenwert. Die Bronchographie galt über Jahrzehnte als Verfahren der Wahl in der Bronchiektasendiagnostik, wurde aber wegen ihrer Invasivität in den letzten Jahren durch die Computertomographie weitgehend ersetzt. Diese kann neben der bronchialen Dilatation auch assoziierte Veränderungen des Lungenparenchyms darstellen. Die computertomographische Diagnose von Bronchiektasen beruht auf dem Nachweis einer fehlenden Verjüngung des Bronchus sowie seiner Dilatation im Vergleich mit der begleitenden Pulmonalarterie. Auch der Nachweis von Bronchien in der Lungenperipherie gilt als wichtiges Kriterium. Die Untersuchung sollte mit hochauflösenden Schichten in Inspiration erfolgen; dickere Schichten sowie Exspirationsaufnahmen können unter bestimmten Umständen nützlich sein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050110
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Niedrigdosiscomputer- tomographie des Thorax Experimentelle und klinische Untersuchungen (1996)
    Springer
    Der Radiologe 36 (1996), S. 475-482 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Computertomographie ; Lunge ; Niedrigdosis-CT ; Strahlenexposition ; Rundherd ; Key words Computed tomography ; Lung ; Low-Dose CT ; Radiation exposure ; Pulmonary nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Introduction. Computed tomography is a significant source of medical radiation exposure for populations in Europe. Reduced radiation exposure may be possible with modern CT scanners with an image quality that while less good than before remains acceptable for clinical purposes. The lung appears particularly well suited to investigation with low-dose CT owing to the high contrast between normal and diseased pulmonary parenchyma. Methods. We analysed the diagnostic accuracy of different low-dose CT protocols for the detection of pulmonary nodules using inflation-fixed isolated postmortem lung specimens in a chest phantom. In a comparative patient study diagnostic accuracies of standard-dose CT (120 kV, 250 mAs; slice thickness 10 mm, pitch 1) and low-dose CT (120 or 140 kV, 50 mAs; slice thickness 5 or 10 mm, pitch 1 or 2) were assessed. Results. Preliminary results suggest that low-dose CT protocols with radiation exposure of 10–20 % of that with standard-dose CT can reliably depict soft tissue density pulmonary nodules with a diameter of more than 5 mm and can also demonstrate smaller nodules equally well in many cases. Conclusions. Low-dose CT may frequently be an adequate imaging procedure in a given clinical setting, particularly in young patients with benign disease.
    Notes: Zusammenfassung Die Computertomographie (CT) trägt wesentlich zur medizinischen Strahlenexposition der Bevölkerung bei. Eine Reduktion dieser Strahlenexposition läßt sich vermutlich mit modernen CT-Geräten bei für viele Fragestellungen vertretbaren Einschränkungen der Bildqualität realisieren. Zur Untersuchung mittels solcher Niedrigdosis-CT (NDCT) erscheint die Lunge aufgrund der günstigen Kontrastverhältnisse des normalen und pathologischen Parenchyms besonders geeignet. Wir untersuchten die Treffsicherheit unterschiedlicher NDCT-Protokolle im Nachweis pulmonaler Rundherde an Lungenpräparaten in einem Thoraxphantom. In einer vergleichenden Patientenstudie wurde die Treffsicherheit der Spiral-CT des Thorax mit etablierten Parametern (120 kV, 250 mAs, Schichtdicke 10 mm, Pitch 1) mit derjenigen verschiedener NDCT-Protokolle (120 oder 140 kV, 50 mAs, Schichtdicke 5 oder 10 mm, Pitch 1 oder 2) verglichen. Vorläufige Ergebnisse zeigen, daß diese NDCT-Protokolle mit einer Dosis von 10 bis 20 % der Standard-Dosis CT weichteildichte Lungenrundherde mit einem Durchmesser von mehr als 5 mm zuverlässig nachweisen konnten und auch bei kleineren Rundherden häufig gleichwertig waren. Abhängig von der Fragestellung sollten derartige NDCT-Protokolle v. a. bei jungen Individuen mit benignen Erkrankungen auch in der klinischen Routine eingesetzt werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050100
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...