The formation of galaxies, clusters and superclusters (SCs) is discussed based on a cosmic string model, and the constrain& are given for the corresponding loops which form these structures by the accretion of the loops. Only those loops that came into horizon after teq (the time of equal matter and radiation) may be the seeds of clusters and SCs.
&BComic s t r i n g s are one-dimensional t o p o l o g i c a l d e f e c t s formed i n cert a i n p r o c e s s of GUT(grand u n i f i e d t h e o r y ) d u r i n g a phase t r a n s i t i o n i n t h e e a r l y u n i v e r s e .Zeldovich' and V i l e n k i n 2 f i r s t r e a l i z e d t h a t e n e r g y
Hetrostructure multilayer thin films of electroactive polymers such as protonated poly(p-pyridyl vinylene), PHPyV, and sulfonated polyaniline, SPAn, have been successfully fabricated via a process based on the spontaneous self-assembly of conjugated polyions on a substrate. The heterostructure thin films formed by these different polymers exhibited a perfectly linear relationship between the absorbance and the number of a SPAn/PHPyV bilayer, SPAn/PHPyV(b), deposited. A greenish-yellow electroluminescent (EL) diode utilizing an SPAn/PHPyV multilayer thin film, SPAn/PHPyV(m), has been produced, and the EL properties of this device are discussed. The EL emission of this device can be qualitatively interpreted in terms of a radiative recombination of the singlet polaron exciton formed by the injection of electrons and holes. The EL intensity of this light-emitting diode is weak. This result is discussed in terms of the quenching centers associated with cationic sites on PHPyV polymer main chain at the heterojunction. The Stokes shift due to the absorption and emission of a phonon is clearly observed in the EL spectrum of this device. A small shift between the EL and PL spectra of SPAn/PHPyV(m) is observed. It was assumed that the EL emission takes place in a narrow region at the interface while the PL emission probes the bulk of the film. The SPAn/PHPyV(b) (LED) emits yellow light, but SPAn/PHPyV(m) emits greenish-yellow light, and there is a slight shift between the two spectra of these devices. These results can be interpreted in terms of the confinement effect of carriers in the superlattice structure of the SPAn/PHPyV (m) system.
Multilayered heterostructures composed of negatively and positively charged conducting polymers have been fabricated by the self-assembly method, and their optical properties and photoconduction have been studied. Remarkable quenching of photoluminescence and enhanced photoconduction are found in the multilayered heterostructure. These phenomena are explained in terms of the efficient photoinduced charge separation at the heterointerfaces between the negatively and positively charged conducting polymers which are thought to act as photodonor and photoacceptor, respectively.
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