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  • 1
    Electronic Resource
    Electronic Resource
    A molecular beam/surface spectroscopy apparatus for the study of reactions on complex model catalysts (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 4395-4408 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a newly developed ultrahigh vacuum (UHV) experiment which combines molecular beam techniques and in situ surface spectroscopy. It has been specifically designed to study the reaction kinetics and dynamics on complex model catalysts. The UHV system contains: (a) a preparation compartment providing the experimental techniques which are required to prepare and characterize single-crystal based model catalysts such as ordered oxide surfaces or oxide supported metal particles; and (b) the actual scattering chamber, where up to three molecular beams can be crossed on the sample surface. Two beams are produced by newly developed differentially pumped sources based on multichannel arrays. The latter are capable of providing high intensity and purity beams and can be modulated by means of a vacuum-motor driven and computer-controlled chopper. The third beam is generated in a continuous or pulsed supersonic expansion and is modulated via a variable duty-cycle chopper. Angular and time-resolved measurements of desorbing and scattered molecules are performed with a rotatable doubly differentially pumped quadrupole mass spectrometer with a liquid-nitrogen cooled ionizer housing. Time-resolved but angle-integrated measurements are realized with a second nondifferentially pumped quadrupole mass spectrometer. In situ measurements of adsorbed species under reaction conditions are performed by means of an adapted vacuum Fourier transform infrared spectrometer. The spectrometer provides the possibility of time-resolved measurements and can be synchronized with any of the beam sources. This contribution provides a general overview of the system and a description of all new components and their interplay. We also present test data for all components employing simple adsorption/desorption and reaction systems. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1318919
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  • 2
    Electronic Resource
    Electronic Resource
    Design of nondestructive emittance measurement device for H− beams : Papers from the Ninth International Conference on Ion Sources (2002)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 998-1000 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: For the diagnostics of high-brightness particle beams as necessary for the European Spallation Source, spallation neutron source IFMIF (D1+), and HIDIF (Bi1+) nondestructive methods have to be developed. Conventional beam diagnostics are established, but are mostly destructive methods and suffer from the power density deposited on surfaces like slits or pinhole plates and beam loss. For negative ions a nondestructive method based on photoneutralization can be used to determine the transverse phase space distribution with high time resolution and a large number of phase space points. The interaction of laser light and H− ions produces a small number of neutral atoms as well as detached electrons. The beam of charged particles is separated magnetically from the neutral beam and the distribution of neutral hydrogen is measured. Under the assumption that the influence of the dipole is small enough, the laser induced emittance measurement can be used, e.g., near the entrance of radio-frequency quadrupole. The basic concept for the laser driven emittance measurement device will be presented together with design considerations and preliminary simulations on ion beam transport. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1431413
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  • 3
    Electronic Resource
    Electronic Resource
    The CO oxidation kinetics on supported Pd model catalysts: A molecular beam/in situ time-resolved infrared reflection absorption spectroscopy study (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 4669-4684 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Combining molecular beam techniques and time-resolved infrared reflection absorption spectroscopy (TR-IRAS) we have studied the kinetics of the CO oxidation reaction on an alumina-supported Pd model catalyst. The Pd particles are deposited by metal evaporation under ultrahigh vacuum (UHV) conditions onto a well-ordered alumina film, prepared on a NiAl(110) single crystal. Particle size, density and structure of the Pd deposits have been characterized in previous studies. In the low temperature region, transient and steady-state experiments have been performed over a wide range of CO and oxygen fluxes by crossing two effusive molecular beams on the sample surface. We determine the steady-state CO2 production rate as a function of the CO fraction in the impinging gas flux. Simultaneously, the occupation of CO adsorption sites under steady-state conditions is monitored by in situ IR spectroscopy. The origin of different types of CO2 transients is discussed. In particular we focus on the transient CO2 production after switching off the CO beam. For the model catalyst investigated, detailed reaction rate measurements in combination with time-resolved IRAS show that the origin of the particular transient behavior of the supported model system is not due to the presence of specific adsorption sites on small particles, as has been proposed previously. Instead, we show that the transient behavior can be semiquantitatively simulated on the basis of a simple kinetic model considering a homogeneous surface, and accounting for the inhibition of the dissociative adsorption of O2 at high CO coverage. Moreover, it is discussed how the inherent heterogeneity of the supported particle system can additionally enhance the observed effect. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1342240
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  • 4
    Electronic Resource
    Electronic Resource
    3D Si-on-Si stack packaging (2000)
    Bradford : Emerald
    Soldering & surface mount technology 12 (2000), S. 35-39 
    Details
    ISSN: 0954-0911
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A new concept of 3D-electronic packaging is presented: Si-on-Si multi-chip module flip-chip technology with arrays of fine etched and filled vertical electrical interconnections (vias). Arrays of vias with a high number of interconnections, and not only peripheral interconnections are used. A 3D Si-on-Si stack package demonstrator has been realized consisting of four Si-substrates each representing a system level and containing four thinned and flip-chip assembled chips. The chips are flip-chip mounted on the flat side of the Si-substrates. When interconnecting the Si-substrates by bump technology the chips submerge into cavities on the rear side of the adjacent Si-substrate. The chips also test the technology and quality of the electronic packaging, and therefore contain a set of thin film heaters, junctions for temperature measuring, Al-meanders for stress and strain measuring and daisy chains for conduction path monitoring.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/09540910010312429
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  • 5
    Electronic Resource
    Electronic Resource
    Canine kidney preservation by pulsatile and nonpulsatile perfusion
    Amsterdam : Elsevier
    Cryobiology 11 (1974), S. 570 
    Details
    ISSN: 0011-2240
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0011-2240(74)90225-9
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  • 6
    Electronic Resource
    Electronic Resource
    Stereoselectivity of lipases: esterification reactions of octadecylglycerol
    Amsterdam : Elsevier
    Chemistry and Physics of Lipids 61 (1992), S. 193-198 
    Details
    ISSN: 0009-3084
    Keywords: esterification ; lipases ; octadecylglycerol ; stereoselectivity
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0009-3084(92)90012-E
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  • 7
    Electronic Resource
    Electronic Resource
    A carlina oxide derivative from Carlina diae
    Amsterdam : Elsevier
    Phytochemistry 20 (1981), S. 823-824 
    Details
    ISSN: 0031-9422
    Keywords: Carlina diae ; Compositae ; new carlina oxide derivative ; new phenyl heptene diyne.
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0031-9422(81)85186-2
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  • 8
    Electronic Resource
    Electronic Resource
    269. Die Durchströmungsverteilung bei hypothermer Nierenperfusion (1974)
    Springer
    Langenbeck's archives of surgery 337 (1974), S. 887-887 
    Details
    ISSN: 1435-2451
    Keywords: Kidney Preservation ; Flow Distribution ; Silicon Rubber Injection ; Nierenkonservierung ; Durchströmungsverteilung ; Silikongummiinjektion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Durchströmungsverteilung in hypotherm perfundierten Nieren wurde durch Injektion einer Silikongummilösung sichtbar gemacht. A. In einer vergleichenden Untersuchung am Hund konnte gezeigt warden, daß sich Nieren in gleicher Weise pulsierend und nichtpulsierend konservieren lassen. B. Humannieren warden bis zu 96 Std nichtpulsierend perfundiert: es fand sich trotz des extrem niedrigen Perfusionsdruckes von 20 mm Hg eine gleichmäßige Perfusion von Mark und Rinde. C. In Nieren ohne ausreichende Sofortfunktion war nur eine geringe Rindenperfusion nachweisbar.
    Notes: Summary The intrarenal flow distribution in kidneys perfused under hypothermia was visualized by means of silicon rubber injection. (A) It was demonstrated that pulsatile and nonpulsatile perfusion yield equivalent results. (B) After nonpulsatile perfusion of human cadaver kidneys for up to 96 hr a uniform intrarenal flow distribution was found although an extremely low perfusion pressure (20 mm Hg) was used. (C) In kidneys that showed poor function immediately after transplantation the cortex was only slightly perfused.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01278902
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  • 9
    Electronic Resource
    Electronic Resource
    Oligonucleotide DNA fingerprinting discriminates super- and half-sisters in honeybee colonies (Apis melifera L.) (1991)
    Springer
    Naturwissenschaften 78 (1991), S. 422-424 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01133418
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  • 10
    Electronic Resource
    Electronic Resource
    Increasing sensitivity and specificity of Doppler sonographic detection of renal transplant rejection with serial investigation technique (1994)
    Springer
    Journal of molecular medicine 72 (1994), S. 609-615 
    Details
    ISSN: 1432-1440
    Keywords: Ultrasonography ; Doppler sonography ; Kidney transplantation ; Graft rejection ; Kidney tubular necrosis acute
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acute rejection episodes are the most common cause leading to loss of renal grafts in the early postoperative phase. Doppler sonography presents a noninvasive tool to detect increased arterial blood flow resistance as a result of rejection. This can be measured by the increase in the resistive index (RI) and the pulsatility index (PI). In a prospective study including 65 consecutive patients we investigated whether the detection of rejection episodes is improved by determining RI or PI serially twice a week instead of performing a single examination in cases of transplant dysfunction. In 330 examinations with a color-coded Doppler device (Philips QAD 1, Philips Medical Systems Hamburg, Germany) flow profiles were obtained by means of pulse-wave Doppler over at least three interlobar arteries of the renal transplant and RI and PI were calculated. In 41 cases primary rejections were better recognized by an increase in PI compared to the preceding value than by the absolute PI value (with a sensitivity of 90%; specificity was 76% and 42% respectively). The RI was less specific (with a sensitivity of 90%; specificity was 47% for the relative RI increase and 30% for the absolute RI value). The continuous PI increase started an average of 3.3 days (95% CI −15.25 to + 1.55) before rejection was diagnosed. Vascular rejection episodes showed higher PI values than interstitial rejections (3.86 ± 2.14 vs. 2.19 ± 0.87; P 〈 0.01). The serial investigation technique of PI allows better recognition of rejection episodes than the single measurement of RI or PI performed so far. Doppler sonography recognizes rejection at an early stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227454
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