Spectrophotometric studies of the photolysis of diazido-bis(phosphine)-metal(II) complexes

The photolysis of mixed ligand complexes of the type MLn(N3)2 (M=Ni, Pd, Pt; L = phosphane and diphosphane ligands, respectively; n = 1, 2) was monitored by electronic spectroscopy in absorption, emission and excitation. Initial quantum yields of these complexes were measured in CH2Cl2 and EtOH in dependence on the irradiation wavelength. Photochemically formed MOIn fragments of Pd and Pt are distinguished by an intensive emission detected at 77 K. No emission was observed with respect to the appropriate NiO fragments. An initial emission at 615 nm detected by irradiating Pd(PPh3)2(N3)2 at 77 K is explained by assuming a photochemical cis/trans isomerization Quenching experiments have been performed by using Ru(bpy)3Cl2, Os(bpy)3Cl2, Re(CO)3(phen)Cl and Cr(bpy)3(ClO4)3 as sensitizers and the mixed-ligand complexes under discussion as quenchers

Low-Speed Aerodynamic Characteristics of a Fuselage Model with Various Arrangements of Elongated Lift Jets

Data were obtained for a round jet located on the center of the bottom of a fuselage and for elongated slots separated spanwise by distances of 0.8 and 1.2 of the fuselage width. The effect of yawing the slots, inclining the jets laterally, and combining slot yaw with jet inclination was determined. Data were obtained in and out of ground effect through a range of effective velocity ratios and through a range of sideslip angles

Native and Naturalized Turf Species Suitable for Use on Airfields Managed for Wildlife Hazards in the Northeast

Habitat management is an important component of an integrated approach for reducing wildlife hazards on airfields. This research examines alternative turf species that are either native or naturalized in the northeastern United States. Many native turf species tend to not be attractive to wildlife due to their low palatability and seed production. These species may have uses on airfields, golf courses and in residential areas where geese and other wildlife are in conflict with humans. While the low seed productivity in some native species is a wildlife deterrent, this same trait is associated with poor establishment rates. Our goal was to find the most successful means of germinating these species using a hydroseeding application so they can be utilized as part of an airfield vegetation management design. Our data will show the evaluation of plant vigor conducted under controlled greenhouse conditions. Some of the species tested include Pennsylvania sedge (Carex pennsylvanica), little bluestem (Schizachyrium scoparium), crinkled hair grass (Deschampsia flexuosa), and purple love grass (Eragrostis spectabilis). By evaluating each species for their suitability for hydroseeding, germination, and early vigor we are able to make recommendations for hydroseeding native species at airfields managed for reducing wildlife hazards

Robustness of a bisimulation-type faster-than preorder

TACS is an extension of CCS where upper time bounds for delays can be specified. Luettgen and Vogler defined three variants of bismulation-type faster-than relations and showed that they all three lead to the same preorder, demonstrating the robustness of their approach. In the present paper, the operational semantics of TACS is extended; it is shown that two of the variants still give the same preorder as before, underlining robustness. An explanation is given why this result fails for the third variant. It is also shown that another variant, which mixes old and new operational semantics, can lead to smaller relations that prove the same preorder.Comment: Express Worksho

Correlative Microscopy of Morphology and Luminescence of Cu porphyrin aggregates

Transfer of energy and information through molecule aggregates requires as one important building block anisotropic, cable-like structures. Knowledge on the spatial correlation of luminescence and morphology represents a prerequisite in the understanding of internal processes and will be important for architecting suitable landscapes. In this context we study the morphology, fluorescence and phosphorescence of molecule aggregate structures on surfaces in a spatially correlative way. We consider as two morphologies, lengthy strands and isotropic islands. It turns out that phosphorescence is quite strong compared to fluorescence and the spatial variation of the observed intensities is largely in line with the amount of dye. However in proportion, the strands exhibit more fluorescence than the isotropic islands suggesting weaker non-radiative channels. The ratio fluorescence to phosphorescence appears to be correlated with the degree of aggregation or internal order. The heights at which luminescence saturates is explained in the context of attenuation and emission multireflection, inside the dye. This is supported by correlative photoemission electron microscopy which is more sensitive to the surface region. The lengthy structures exhibit a pronounced polarization dependence of the luminescence with a relative dichroism up to about 60%, revealing substantial perpendicular orientation preference of the molecules with respect to the substrate and parallel with respect to the strands

Chandra Snapshot Observations of Low-Luminosity AGNs with a Compact Radio Source

The results of Chandra snapshot observations of 11 LINERs (Low-Ionization Nuclear Emission-line Regions), three low-luminosity Seyfert galaxies, and one HII-LINER transition object are presented. Our sample consists of all the objects with a flat or inverted spectrum compact radio core in the VLA survey of 48 low-luminosity AGNs (LLAGNs) by Nagar et al. (2000). An X-ray nucleus is detected in all galaxies except one and their X-ray luminosities are in the range 5x10^38 to 8x10^41 erg/s. The X-ray spectra are generally steeper than expected from thermal bremsstrahlung emission from an advection-dominated accretion flow (ADAF). The X-ray to Halpha luminosity ratios for 11 out of 14 objects are in good agreement with the value characteristic of LLAGNs and more luminous AGNs, and indicate that their optical emission lines are predominantly powered by a LLAGN. For three objects, this ratio is less than expected. Comparing with properties in other wavelengths, we find that these three galaxies are most likely to be heavily obscured AGN. We use the ratio RX = \nu L\nu (5 GHz)/LX, where LX is the luminosity in the 2-10 keV band, as a measure of radio loudness. In contrast to the usual definition of radio loudness (RO = L\nu(5 GHz)/L\nu(B)), RX can be used for heavily obscured (NH >~ 10^23 cm^-2, AV>50 mag) nuclei. Further, with the high spatial resolution of Chandra, the nuclear X-ray emission of LLAGNs is often easier to measure than the nuclear optical emission. We investigate the values of RX for LLAGNs, luminous Seyfert galaxies, quasars and radio galaxies and confirm the suggestion that a large fraction of LLAGNs are radio loud.Comment: 15 pages, accepted for publication in Ap