Nanocrystals of several oligosilanes have been fabricated easily by using a reprecipitation method. The nanocrystals reveal an intense absorption band at the UVB region (280 to 320 nm) and a fluorescence band with large Stokes shift. These photophysical properties show that the nanocrystals exhibit an excitonic interaction of the H-aggregate type.

BACKGROUND Minimal erythemal dose (MED) for narrow band-ultraviolet B radiation (NB-UVB) varies with race and skin type. The aim was to estimate the MED for NB-UVB and compare visual readings with those from a Dermaspectrometer in a north Indian patients as the available data is sparse. METHODS Forty one patients who visited the dermatology outpatient department were recruited for this study....

We describe the reduction from four to two dimensions of the SU(2) Donaldson-Witten theory and the dual twisted Seiberg-Witten theory, i.e. the Abelian topological field theory corresponding to the Seiberg–Witten monopole equations. NBI-HE-96-14 hep-th/9603023 ∗E-mail: [email protected]

The 150 Sm nucleus has been studied to high spins in a measurement of γ radiation following the 136 Xe(18 O,4n) 150 Sm, compound-nucleus reaction at beam energy of 76 MeV. The measurement was performed at NBI Risø using the NORDBALL array. Alternating parity, s=+1 band in 150 Sm has been observed up to spin I=22. This band is crossed by two aligned bands, corresponding to a reflection-symmetric...

We discuss the general structure of the non–abelian Born–Infeld action, together with all of the α derivative corrections, in flat D–dimensional space– time. More specifically, we show how the connection between open strings propagating in background magnetic fields and gauge theories on non–commutative spaces can be used to constrain the form of the effective action for the massless modes of o...

A review of the applications of noncommutative geometry to a systematic formulation of duality symmetries in string theory is presented. The spectral triples associated with a lattice vertex operator algebra and the corresponding Dirac-Ramond operators are constructed and shown to naturally incorporate target space and discrete worldsheet dualities as isometries of the noncommutative space. The...

Studies of voluntary exposure to ultraviolet-B (UVB) radiation from the sun in the field were conducted in the southern US and Jamaica for 15 species of lizards and snakes occupying various habitats. Species were sorted into four zones of UVB exposure ranging from a median UV index of 0.35 for zone 1 to 3.1 for zone 4. Guidelines for UVB exposure in captivity of these and species occupying simi...

Performance of the conventional narrowband active noise control (NANC) system may degrade severely when the uncorrelated narrowband disturbance noise is present in the system. In this paper, we propose a new hybrid NANC system capable of reducing the primary noise and the uncorrelated disturbance simultaneously. First, some simple analysis is used to show why the NANC system may indicate poor p...

The ∆-operator of the Batalin-Vilkovisky formalism is the Hamiltonian BRST charge of Abelian shift transformations in the ghost momentum representation. We generalize this ∆-operator, and its associated hierarchy of antibrackets, to that of an arbitrary non-Abelian and possibly open algebra of any rank. We comment on the possible application of this formalism to closed string field theory. NBI-...