Sheaves on Involutive Quantaloids

We extend the well-known notions of a singleton, complete jh0604ql01/10986_2004_Article_303234_TeX2GIFIE1.gif" alt=" $$Q$$ " align="middle" border="0"> -set, presheaf and sheaf over a complete Heyting algebra or a right-sided idempotent quantale to arbitrary involutive quantaloids. We show that sheaves on jh0604ql01/10986_2004_Article_303234_TeX2GIFIE2.gif" alt=" $$Q$$ " align="middle" border="0"> and complete jh0604ql01/10986_2004_Article_303234_TeX2GIFIE3.gif" alt=" $$Q$$ " align="middle" border="0"> -sets come to the same thing. This paper can be considered as a jh0604ql01/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">symmetricjh0604ql01/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> version of an earlier work of the author.     

Point-source spark shadowgraphy at the historic birthplace of supersonic transportation

About a decade after its foundation, the most advanced ballistics laboratory in Germany at the time, the jh9da5xtqc2djej/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">Kruppsche Schiessplatz,jh9da5xtqc2djej/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> was utilized by Ernst Mach in 1888. His intent was to validate his pioneering shock wave research using military shells as supersonic vehicles. The 125th anniversary of the Schiessplatz was celebrated in 2002. Along with Machjh9da5xtqc2djej/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s research, it served to initiate the field of supersonic transportation technology. The specific subject of this paper is the application of point-source spark shadowgraphy at the same laboratory in the 1970jh9da5xtqc2djej/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s to visualize gas flow over aeroballistic projectiles. However, different from Machjh9da5xtqc2djej/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s original interest, the new purpose of spark photography at that time in the ballistic ranges of the German Bundeswehr was to find technical solutions to aeroballistic problems when field-testing gave incomplete answers. Both a qualitative and a quantitative understanding of the principles of aeroballistics were sought in this research.Received: 3 February 2003, Accepted: 30 June 2003, Published online: 2 September 2003An abridged version of this paper was presented at the 13th American Physical Society Topical Conference on Shock Compression of Condensed Matter at Portland, Oregon, from July 20 to 25, 2003     

Discontinuous flow-through measurement of gamma-rays. Principles of operation and application in clinical biochemistry

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Discontinuous flow-through measurement of gamma-rays. Principles of operation and application in clinical biochemistry

     

Coherent and transient states studied with extreme ultraviolet and X-ray free electron lasers: present and future prospects

The most recent light sources, extreme ultraviolet (EUV) and X-ray free electron lasers (FELs), have extended tabletop laser experiments to shorter wavelengths, adding element and chemical state specificity by exciting and probing electronic transitions from core levels. Through their unique properties, combining femtosecond X-ray pulses with coherence and enormous peak brightness, the FELs have enabled studies of a broad class of dynamic phenomena in matter that crosses many scientific disciplines and have led to major breakthroughs in the last few years. In this article, we review how the advances in the performance of the FELs, with respect to coherence, polarization and multi-color pulse production, have pushed the development of original experimental strategies to study non-equilibrium behavior of matter at the femtosecond–nanometer time–length scales. In this review, the emphasis is placed on the contribution of the EUV and soft X-ray FELs on three important subjects: (i) the new regime of X-ray matter interactions with ultrashort very intense X-ray pulses, (ii) the new potential of coherent imaging and scattering for answering questions about nano dynamics in complex materials and (iii) the unique possibility to stimulate and probe nonlinear phenomena that are at the heart of conversion of light into other forms of energy, relevant to photovoltaics, femtosecond magnetism and phase transitions in correlated materials.     

Interface formation in CdTe solar cells: Nucleation of CdTe on CdS(0001) and (10$ \bar 1 $0)

The growth of CdTe on (0001) and (10 0) surfaces of CdS was studied using low energy electron diffraction and photoelectron spectroscopy. The results indicate oriented growth of the CdTe films with a faster nucleation of CdTe on CdS(0001), explaining the preferred (111) orientation of CdTe films on polycrystalline substrates. The faster nucleation on the (0001) surface is attributed to the formation of a stable CdS(0001):Te surface termination, which is identified from surface sensitive Te 4d spectra and a 2√3 × 2√3 surface reconstruction. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth of oriented crystalline Ag nanoislands on air-exposed Si(0 0 1) surfaces

Growth of Ag islands under ultrahigh vacuum condition on air-exposed Si(0 0 1)-(2 × 1) surfaces has been investigated by in-situ reflection high energy electron diffraction (RHEED). A thin oxide is formed on Si via exposure of the clean Si(0 0 1)-(2 × 1) surface to air. Deposition of Ag on this oxidized surface was carried out at different substrate temperatures. Deposition at room temperature leads to the growth of randomly oriented Ag islands while well-oriented Ag islands, with (0 0 1)_Ag||(0 0 1)_Si, [1 1 0]_Ag||[1 1 0]_Si, have been found to grow at substrate temperatures of ≥350 °C in spite of the presence of the oxide layer between Ag islands and Si. The RHEED patterns show similarities with the case of Ag deposition on H-passivated Si(0 0 1) surfaces.     

Experimental correlation between photoemission matrix elements and LEED intensities in superperiodic structures

A direct comparison between photoemission measurements and band structure calculations is sometimes tricky. Matrix element effects may affect considerably the spectral weight of the electronic states and prevent the expected translational symmetry of the band structure from being observed. We show how matrix element effects can be qualitatively described to a certain extent by making an analogy between photoemission and low energy electron diffraction. We have tested this approach in two superperiodic systems. We have first explained the intensity distribution in different Brillouin zones of a surface state in Si(1 1 1)-(7 × 7), where the surface state spectral intensity does not exhibit the (7 × 7) symmetry. We have also compared the LEED intensity of superperiodic LEED spots with the energy dependence of bulk bands on a facetted Si surface as measured by photoemission.     

Synthesis and Crystal Structure of a New Copper–PMIDA Compound (H4PMIDA=H2O3PCH2N(CH2CO2H)2)

A new Cu(II)PMIDA compound [Cu(H₂PMIDA)(phen)] jh9/xxlarge8901.gif" alt="sdot" align="BASELINE" BORDER="0"> 3H₂O (1) (H₄PMIDA = H₂O₃PCH₂N (CH₂CO₂H)₂,phen = 1,10-phenanthroline) has been successfully synthesized and structurally characterized. In complex 1, Cu (II) is six coordinated by chelation in a tetradentate fashion by a PMIDA ligand and by two N atoms of a phen ligand. Every phen–Cu(II)–PMIDA group connects with each other via a hydrogen bond and the edge-to-face jh9/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-stacking interaction. Complex 1 crystallized in triclinic P-1 with cell dimensions of a = 7.5817(6) Å, b = 10.6980(8) Å, c = 13.1852(10) Å, jh9/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">=82.350(2)°, jh9/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> = 84.151(2)°, jh9/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">=78.4250(2), V= 1035.25(14) ų, Z = 2, Dc = 1.677 Mg/m³.     

Ein einfacher Zugang zu (R)-γ-Amino-β-hydroxybuttersäure (GABOB) aus natürlichem (2S, 4R)-4-Hydroxyprolin

The oxidative decarboxylation sequence (1a jh612k43370v346k/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0"> 2a jh612k43370v346k/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0"> 3a jh612k43370v346k/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0"> 4a jh612k43370v346k/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0"> 5a) affording jh612k43370v346k/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-aminobutanoic acid (5a) is adapted to the synthesis of its hydroxy derivative5b. A facile high yield conversion of (2S, 4R)-4-hydroxyproline-methylester-hydrochloride (7) to (R)-GABOB (5b) on a preparative scale is reported with the hydroxypyrrolidone8 as the intermediate.