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  • 2005-2009
  • 1990-1994  (20)
  • 1955-1959
  • 1991  (20)
  • 1
    Digitale Medien
    Digitale Medien
    Ionization by electron impact in an indirectly heated Penning source (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 151-154 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: ion-production mechanism in an indirectly heated Penning source has been studied at NIRS. Taking the number of primary electron passages between two cathodes into account, we calculated the effective electron current density, Ji ; it is the order of kA/cm2 for Ar, where the index "i'' is the charge state. In a pulsed arc condition of 2.6 A and 1300 V with a neutral atom density of 4×1013/cm3(cw), the calculated ionization times for Ar5+→Ar6+ and Ar6+→Ar7+ are 18 and 28 μs if their production process is step-by-step. These values agree well with the experimental value of 20 μs. Ji is proportional to the arc voltage and inversely proportional to the neutral-atom density N. The yield of multiply charged ions is in proportion to 1/Ni−2. This expression agrees well with the experimental results, which suggest that multiply charged ions are produced from Ar2+ through step-by-step ionization by primary electrons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.347736
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  • 2
    Digitale Medien
    Digitale Medien
    Application of low-temperature ions in the nonequilibrium state plasma of a Penning source (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 7933-7935 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We present the high-output properties during the early 100–200 μs of a pulsed Penning source. The peak intensity, I, is higher than that of a dc source by a factor of more than 10. This phenomenon is due to the long confinement time of ions, τ, at the rising of the plasma, since within such a short time the ion temperature, T, does not reach thermal equilibrium and is still low. These characteristics are expressed as I∝τ∝T−1/2. The ratio of T−1/2 before and after equilibrium has a maximum of 1/18.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.347487
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  • 3
    Digitale Medien
    Digitale Medien
    Observation of continuum absorption spectra in far wings of the Yb resonance line broadened by He, Ne, Ar, Kr, Xe, and Yb (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 8083-8088 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: We have determined reduced absorption coefficients in far wings of the Yb (6s2)1S0–(6s6p)1P1 line broadened by He, Ne, Ar, Kr, Xe, and Yb. We find a prominent blue-satellite peak for all perturbers and undulations between the satellite peak and the line center for Ne, Ar, Kr, and Xe. Analyzing the satellite band with the aid of the unified Franck–Condon method, we obtain the position and the height of the extremum on the difference potential-energy curves concerned. We have also observed collision-induced-dipole absorption bands associated with the transition (6s2)1S0–(6s5d)3D2 of atomic Yb for Ne, Ar, Kr, and Xe perturbers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.461815
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  • 4
    Digitale Medien
    Digitale Medien
    Observation of far-wing absorption bands of the Ba 6s2 1S0–5d6p 1P1 line broadened by rare gases (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 1903-1906 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: We have determined reduced absorption coefficients on far wings of the Ba 6s2 1S0–5d6p 1P1 line broadened by He, Ne, Ar, Kr, and Xe. Using the unified Franck–Condon theory, we analyzed the blue satellite band observed for each of the He, Ne, and Ar perturbers and obtained the position and the height of the extremum of the difference potential-energy curve to be 6.5±1.5 A and 251±4 cm−1 for He, 7.6±2 A and 114±2 cm−1 for Ne, and 7.4±2 A and 70±2 cm−1 for Ar. We have also observed the collision-induced–dipole absorption bands associated with the Ba 6s2 1S0–6s7s 1S0 forbidden transition for all rare-gas perturbers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.460712
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  • 5
    Digitale Medien
    Digitale Medien
    Observation of pair absorption and self-broadening in Ba vapor (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 1907-1912 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Reduced absorption coefficients γBaBa were measured for the far-wing absorption of the self-broadened Ba6s2 1S0–5d6p 1P1 line, Ba(6s2 1S0) +Ba(6s2 1S0)+(h-dash-bar)ω → Ba*(5d6p 1P1)+Ba(6s21 S0)and the pair absorption Ba(6s2 1S0)+Ba(6s2 1 S0) +(h-dash-bar)ω→Ba*(6s6p 1P1 +Ba*(6s5d 1D2). The self-broadening shows the red-shaded asymmetric profile: γBaBa on the red wing is proportional to Δν−3/2, where Δν is the detuning from the line center. The pair absorption shows a broad asymmetric peak having a blue tail and a blue satellite. The estimated γBaBa, which is based on the quasistatic line-broadening theory and the long-range dipole–dipole interaction between the relevant atomic excited levels, shows reasonable agreement for the red wing of the self-absorption whereas it gives larger values by a factor of 3 for the blue tail of the main peak for the pair absorption.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.459911
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  • 6
    Digitale Medien
    Digitale Medien
    Effect of hydrotreatment of various heavy oils as solvent for coal liquefaction (1991)
    s.l. : American Chemical Society
    Energy & fuels 5 (1991), S. 98-102 
    Details
    ISSN: 1520-5029
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Energietechnik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ef00025a017
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  • 7
    Digitale Medien
    Digitale Medien
    Morphogenesis of the cornoid lamella: histochemical, immunohistochemical, and ultrastructural study of porokeratosis (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cutaneous pathology 18 (1991), S. 0 
    Details
    ISSN: 1600-0560
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: To elucidate the morphogenesis of cornoid lamellae (CL) in porokeratosis, skin lesions of three cases of disseminated superficial actinic porokeratosis and a case of linear porokeratosis were examined. By N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide staining, SH groups were present in the living layer of the epidermis beneath CL and irregularly disappeared at the bottom of CL, whereas SS linkages appeared in dyskeratotic cells in the living layer and in the irregularly shaped cell membranes of the horny cells. Epidermis beneath CL showed an increased and irregular involucrin expression. Ultrastructurally, the living keratinocytes contained many cytoplasmic vacuoles and had a smaller number of lamellar bodies than normal. Intercellular lamellar sheets were incompletely formed. The dyskeratotic cells and the lower horny cells contained many small vacuoles but formed a marginal band. The horny cells of CL also formed a marginal band and, further, a keratin pattern. CL may be formed by hyperproliferative atypical kertatinocytes which keratinize rapidly and irregularly and show defective desquamation due to the paucity of intercellular lamellar sheets.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1600-0560.1991.tb01231.x
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  • 8
    Digitale Medien
    Digitale Medien
    Proliferating trichilemmal cyst with apocrine-acrosyringeal and sebaceous differentiation (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cutaneous pathology 18 (1991), S. 0 
    Details
    ISSN: 1600-0560
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: An adnexal tumor on the scalp of a 74-year-old woman is described. Histologically, the tumor was composed of cystic structures showing typical trichilemmal keratinization. The tumor cells in the cyst walls often formed duct-like or squamous eddy-like structures and occasionally showed vacuolation or poromalike change. Ultrastructurally, some tumor cells showed differentiation either toward the acrosyringium or sebaceous cells. From these findings, the present tumor is considered to differentiate toward various parts of the hair follicle including infundibulo-isthmus epithelium, apocrine acrosyringium, and sebaceous cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1600-0560.1991.tb00142.x
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  • 9
    Digitale Medien
    Digitale Medien
    Ultrastructural study of a mucinous carcinoid of the skin (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cutaneous pathology 18 (1991), S. 0 
    Details
    ISSN: 1600-0560
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: A tumor of 60 years' duration overlying the sternum of an 87-year-old woman is described. Histologically, the tumor was composed of lobules and cords of epithelial cells with finely granular, eosinophilic cytoplasm. The epithelial nests were floating in large pools of mucinous stroma, separated by thin fibro-vascular septa. Cytoplasmic argyrophilia was seen by Grimelius silver stain. Positive reactions of the tumor cells were also found for chromogranin and neuron-specific enolase. Ultrastructural study revealed that the cytoplasm of the tumor cells contained two types of granules: neurosecretory and mucinous. From these findings, the present tumor is considered to be a carcinoid tumor with amphicrine cells, and the term ‘mucinous carcinoid’ of the skin seems to be appropriate for the diagnosis of the present case.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1600-0560.1991.tb00140.x
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  • 10
    Digitale Medien
    Digitale Medien
    Comparison of a PACS workstation with conventional film for interpretation of neonatal examinations: a paired comparison study (1991)
    Springer
    Pediatric radiology 21 (1991), S. 336-340 
    Details
    ISSN: 1432-1998
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The diagnostic value of neonatal examinations using picture archiving and communication systems (PACS) was compared with that of conventional radiographs. A total of 202 consecutive chest or abdominal radiographs from the newborn intensive care unit were digitized for display on a commercially available PACS console. Experimental design was a paired comparison study. Plain films and PACS images were reviewed alternately in unbiased fashion. After the examination was evaluated using the second modality, any change in diagnosis or confidence in diagnosis was noted. Overall evaluation showed slight preference for the PACS modality. Change of diagnosis or in confidence of diagnosis was more than twice as likely to occur with evaluation of PACS (35%) after hadcopy than with evaluation of conventional radiographs (14%) after PACS. Of the variety of image processing features available on PACS, only window and leveling were judged to be of significant value. These results indicate that PACS and conventional radiographs of the neonatal chest and abdomen are of similar diagnostic value.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02011481
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