Ideals contracted from 1-dimensional overrings with an application to the primary decomposition of ideals

We prove that each ideal of a locally formally equidimensional analytically unramified Noetherian integral domain is the contraction of an ideal of a one-dimensional semilocal birational extension domain. We give an application to a problem concerning the primary decomposition of powers of ideals in Noetherian rings. It is shown in an earlier paper by the second author that for each ideal in a Noetherian commutative ring there exists a positive integer such that, for all , there exists a primary decomposition where each contains the -th power of its radical. We give an alternate proof of this result in the special case where is locally at each prime ideal formally equidimensional and analytically unramified.

     

Optical coherence tomography using a frequency-tunable optical source

We have developed a simple, wide-optical-bandwidth, high-resolution system for performing rapid optical frequency domain reflectometry measurements and applied it to multidimensional tomographic imaging. The source is a grating-tuned external cavity semiconductor laser with a tuning capability of 25 nm in 100 ms. We discuss system performance and show a two-dimensional optical coherence tomography image of a thin glass sandwich structure as a preliminary demonstration of the systems depth and resolution capabilities.     

Self-assembled diisocyanide monolayer films on gold and palladium

Self-assembled monolayers (SAMs) of the aromatic diisocyanides, 1,4-phenylenediisocyanide, 2,3,5,6-tetramethyl-1,4-phenylenediisocyanide, 4,4'-biphenyldiisocyanide, 3,3',5,5'-tetramethyl-4,4'-biphenyldiisocyanide, and 4,4' '-p-terphenyldiisocyanide, were prepared on gold and palladium surfaces. The SAMs were characterized by ellipsometry, polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS), and grazing-angle attenuated total reflectance infrared spectroscopy (GATR). Based on the position of the metal-coordinated isocyanide stretching band, the SAMs on gold were found to bind in the terminal (eta(1)) geometry, while the SAMs on palladium prefer a different geometry which is possibly a triply bridging (mu(3)-eta(1)) geometry. A side-reaction of the unbound isocyanide in the SAM was identified as oxidation to an isocyanate group.     

Citrafungins A and B, two new fungal metabolite inhibitors of GGTase I with antifungal activity

[structure: see text] Screening of natural products extracts led to the discovery of citrafungins A and B, two new fungal metabolites of the alkylcitrate family that are inhibitors of GGTase I of various pathogenic fungal species with IC(50) values of 2.5-15 microM. These compounds exhibited antifungal activities with MIC values of 0.40-55 microM. The isolation, structure elucidation, relative and absolute stereochemistry, and biological activities of citrafungins are described.     

Detection of vacancy clustering by combined PAC and lattice location measurements

The formation of impurity-vacancy agglomerates starting with the trapping of monovacancies was studied using a combination of three complementary techniques applied to the system InCu: Perturbed -angular correlation, ion channeling and channeling of conversion electrons. This results in an almost complete picture of the first stage of vacancy agglomeration at In impurities in Cu.This work was supported by the Bundesminister für Forschung und Technologie.     

Quecksilber-Halogensysteme, 2. Mitt.: Das System Quecksilber-Jod

Zusammenfassung Das System Hg–J₂ wurde thermoanalytisch und visuell untersucht. Im System J₂–HgJ₂ bildet J₂ mit HgJ₂ ein Eutektikum bei 14,5 Mol% HgJ₂ und 101,3°C. Rotes HgJ₂ wandelt sich bei 131,2°C in gelbes HgJ₂ um, welches bei 256,7°C schmilzt. Im System HgJ₂–Hg liegt zwischen HgJ₂ und Hg₂J₂ ein Eutektikum bei 82,7 Mol% HgJ₂ und 231,4°C. Bei erstmaligem Aufheizen schmilzt Hg₂J₂ bei 296°C. Unter Gleichgewichtsbedingungen bildet sich Hg₂J₂ syntektisch bei 241,5°C aus einer HgJ₂-reichen Schmelze mit 79 Mol% HgJ₂ und einer Hg-reichen Schmelze mit<0,5 Mol% HgJ₂. Zwischen diesen beiden Zusammensetzungen erstreckt sich eine Mischungslücke im flüssigen Zustand. Die kritische Temperatur liegt bei 288°C, doch ist die kritische Entmischungskurve zwischen 20 und 60 Mol% HgJ₂ praktisch horizontal. Oberhalb dieser Temperatur herrscht im System J₂–Hg vollkommene Mischbarkeit.Diese Resultate konnten visuell bestätigt werden. Gleichzeitig wurden bei Temperaturänderung charakteristische reversible Farbänderungen beobachtet. Berechnungen der Liquiduskurve ergaben, daß Schmelzen im System J₂–HgJ₂ nahezu ideale Lösungen der Molekülarten J₂ und HgJ₂ darstellen. Bei Zusatz von Hg zu HgJ₂-Schmelzen bilden sich entweder Hg-Atome oder Hg₂J₂-Moleküle. Abschließend werden die Systeme HgX ₂–Hg thermodynamisch diskutiert und mit anderen Metallhalogenid-Metallsystemen verglichen.

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Mercury-halogen systems. II. The mercury-iodine system

The Hg–J₂ system was investigated by thermal analysis and visual observation. In the J₂–HgJ₂ system J₂ forms a eutectic with HgJ₂ at 14.5 mole% HgJ₂ and 101.3°C. Red HgJ₂ transforms at 131.2°C into yellow HgJ₂ which melts at 256.7°C. In the HgJ₂–Hg system a eutectic between HgJ₂ and Hg₂J₂ is observed at 82.7 mole% HgJ₂ and 231.4°C. When heated for the first time Hg₂J₂ melts at 296°C. Under equilibrium conditions Hg₂J₂ is formed by a syntectic reaction at 241.5°C from an HgJ₂-rich melt with 79 mole% HgJ₂ and an Hg-rich melt with<0.5 mole% HgJ₂. A miscibility gap in the liquid state exists between both compositions. The critical temperature is 288°C but the critical immiscibility curve between 20 and 60 mole% HgJ₂ is practically horizontal. Above this temperature the J₂–Hg system is completely miscible. These results could be visually confirmed. Also characteristic reversible color changes with temperature could be observed. From calculations of the liquidus curves it was concluded that the melts in the J₂–HgJ₂ system are nearly ideal solutions of the molecular species J₂ and HgJ₂. Hg dissolves in liquid HgJ₂ either as Hg atoms or as Hg₂J₂ molecules. The HgX ₂–Hg systems are discussed thermodynamically and compared with other metal halogenide-metal systems.

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Mit 3 Abbildungen     

The electric field gradient for Gd in gadolinium metal

We have examined the temperture dependence of the efg for GdGd above the Curie point. Using anI =10⁺ isomer in¹⁴⁴Gd as a probe nucleus, we find a weakT ^3/2 dependence withB=(1.5±0.4) 10^–5 K^–3/2. The absolute value of the efg at 332 K was measured by Coulomb excitation of 2⁺ states in^{156, 158, 160}Gd, yielding |eq(332 K)|=(3.43±0.14) 10¹⁷ V/cm². A possible small deviation from theT ^3/2 temperature dependence of the efg for ferromagnetic Gd is discussed.     

Molecular recognition and self-assembled polymer films for vapor phase detection of explosives

Selective and sensitive polymer films for detecting explosives were studied and fabricated onto surface acoustic wave (SAW) devices. Polymers and molecular host species were self-assembled on functionalized silicon oxide surfaces through a catalytic hydrosilylation reaction. The covalently attached thin polymer films are stable, continuous and uniform with film thickness ranging from 15 to 30 nm. The microsensors coated with the polymer films show high sensitivity towards 2,4-dinitrotoluene (DNT) and o-nitrotoluene, an explosive simulant. Sensor responses to possible common interferents in land mine detection were studied and the sensor sensitivities to them were found to be much lower than that to DNT and explosives simulants. Response patterns for interferants and o-nitrotoluene were constructed and the sensors coated with functionalized cyclodextrins were able to detect 2,4-DNT and 2,4,6-trinitrotoluene (TNT) under ambient laboratory conditions.