9,051 research outputs found
Studies on organic semiconductors. 15: Effects of the substituents on the photoconductivities of substituted anthracenes
The photocurrents of the substituted anthracenes, 1,5-diacetylanthracene (2), 1-acetylanthracene (3), 9-acetylanthracene (4), 1,5-dichloroanthracene (5), 1,5-diethylanthracene (6), 1,5-dimethoxyanthracene (7), 9-cyanoanthracene (8), and anthracene (1) were measured by using their surface type cells in nitrogen. The compounds of (1), (5), (6), (7), and (8) showed the photocurrent spectra which corresponded to the absorption spectra of their evaporated films. In the cases of (2) and (3), however, the anomalous photocurrent appeared in the threshold region of their absorption spectra. The appearance of the anomalous photocurrent was characteristic of anthracenes having the acetyl group at 1- and/or 5-position. The magnitude of the photocurrents of the 1,5-disubstituted anthracenes was similar to that of (1). The photocurrents of the monosubstituted anthracenes were smaller than that of (1). Among the monosubstituted anthracenes, the compound (4) showed no photocurrent under the same conditions. Contrary to the results obtained in the cases of phenazines, the photoconductivities of the anthracene derivatives became better in air
Substituent effects on the electrical conductivities of the phenazine derivatives
The and/or photoconductivities of 16 substituted phenazines having methoxy, hydroxy, chloro, nitro, amino or t-butyl group at 1-, 2-, 1, 6- or 2,7- positions of the phenazine ring measured by using the surface type cells. The energy gaps of the dark conductivities in the range 2.0 to 2.3 were independent of the kinds and the positions of the substituent groups, although the photo-absorption wavelength of the evaporated films changed with them. No correlation between photoconductivity and fluorescence was observed. The photocurrent was affected by the position of the substituents; namely, the photocurrents of the 1,6-di-substituted phenazines. When the substituent at 1,6-positions was hydroxy or amino group, however, the photocurrents decreased. The photocurrents decreased drastically in the presence of oxygen
Preparations of methoxynitrophenazines and their photoconductivities
Eight methoxynitrophenazines with a methoxy group at the 1 or 2 position and a nitro group at the 6-, 7-, 8- or 9-position of the phenazine ring 1,6, 1,7. 1,8, 1,9, 2,6, 2,7, 2,8 and 2,9 were prepared and their photocurrents were measured by illuminating the surface-type cell with white light from a W lamp under a N atmosphere at room temp. The photocurrents of 1-nitrophenazine 6 and 2-nitrophenazine 7 are compared with those of the methoxynitrophenazines. The photocurrent (i sub p) increases with increasing light intensity (I), thus satisfying log i varies as n log I. The n values are 0.5-1.0. When the nitro group is located at the beta-position of the phenazine ring, the photocurrent becomes larger owing to the electron withdrawing property of the nitro group. On the other hand, the photocurrents of phenazines with the nitro group at the Alpha-position are extremely small. The photoconductivities of methoxynitrophenazines are lower in air
Complete solution for unambiguous discrimination of three pure states with real inner products
Complete solutions are given in a closed analytic form for unambiguous
discrimination of three general pure states with real mutual inner products.
For this purpose, we first establish some general results on unambiguous
discrimination of n linearly independent pure states. The uniqueness of
solution is proved. The condition under which the problem is reduced to an
(n-1)-state problem is clarified. After giving the solution for three pure
states with real mutual inner products, we examine some difficulties in
extending our method to the case of complex inner products. There is a class of
set of three pure states with complex inner products for which we obtain an
analytical solution.Comment: 13 pages, 3 figures, presentation improved, reference adde
Requirement of the FATC domain of protein kinase Tel1 for localization to DNA ends and target protein recognition
Two large phosphatidylinositol 3-kinase-related protein kinases (PIKKs), ATM and ATR, play a central role in the DNA damage response pathway. PIKKs contain a highly conserved extreme C-terminus called the FRAP-ATM-TRRAP-C-terminal (FATC) domain. In budding yeast, ATM and ATR correspond to Tel1 and Mec1, respectively. In this study, we characterized functions of the FATC domain of Tel1 by introducing substitution or truncation mutations. One substitution mutation, termed tel1-21, and a truncation mutation, called tel1- Î"C, did not significantly affect the expression level. The tel1-21 mutation impaired the cellular response to DNA damage and conferred moderate telomere maintenance defect. In contrast, the tel1-Î"C mutation behaved like a null mutation, conferring defects in both DNA damage response and telomere maintenance. Tel1-21 protein localized to DNA ends as effectively as wild-type Tel1 protein, whereas Tel1-Î"C protein failed. Introduction of a hyperactive TEL1-hy mutation suppressed the tel1-21 mutation but not the tel1-Î"C mutation. In vitro analyses revealed that both Tel1-21 and Tel1-Î"C proteins undergo efficient autophosphorylation but exhibit decreased kinase activities toward the exogenous substrate protein, Rad53. Our results show that the FATC domain of Tel1 mediates localization to DNA ends and contributes to phosphorylation of target proteins. © 2015 Ogi, Goto, Ghosh, et al
Pre-suprenova evolution of rotating massive stars
The Geneva evolutionary code has been modified to study the advanced stages
(Ne, O, Si burnings) of rotating massive stars. Here we present the results of
four 20 solar mass stars at solar metallicity with initial rotational
velocities of 0, 100, 200 and 300 km/s in order to show the crucial role of
rotation in stellar evolution. As already known, rotation increases mass loss
and core masses (Meynet and Maeder 2000). A fast rotating 20 solar mass star
has the same central evolution as a non-rotating 26 solar mass star. Rotation
also increases strongly net total metal yields. Furthermore, rotation changes
the SN type so that more SNIb are predicted (see Meynet and Maeder 2003 and N.
Prantzos and S. Boissier 2003). Finally, SN1987A-like supernovae progenitor
colour can be explained in a single rotating star scenario.Comment: To appear in proceedings of IAU Colloquium 192, "Supernovae (10 years
of 1993J)", Valencia, Spain 22-26 April 2003, eds. J.M. Marcaide, K.W.
Weiler, 5 pages, 8 figure
Discrimination with error margin between two states - Case of general occurrence probabilities -
We investigate a state discrimination problem which interpolates
minimum-error and unambiguous discrimination by introducing a margin for the
probability of error. We closely analyze discrimination of two pure states with
general occurrence probabilities. The optimal measurements are classified into
three types. One of the three types of measurement is optimal depending on
parameters (occurrence probabilities and error margin). We determine the three
domains in the parameter space and the optimal discrimination success
probability in each domain in a fully analytic form. It is also shown that when
the states to be discriminated are multipartite, the optimal success
probability can be attained by local operations and classical communication.
For discrimination of two mixed states, an upper bound of the optimal success
probability is obtained.Comment: Final version, 9 pages, references added, presentation improve
Time and Tachyon
Recent analysis suggests that the classical dynamics of a tachyon on an
unstable D-brane is described by a scalar Born-Infeld type action with a
runaway potential. The classical configurations in this theory at late time are
in one to one correspondence with the configuration of a system of
non-interacting (incoherent), non-rotating dust. We discuss some aspects of
canonical quantization of this field theory coupled to gravity, and explore,
following earlier work on this subject, the possibility of using the scalar
field (tachyon) as the definition of time in quantum cosmology. At late `time'
we can identify a subsector in which the scalar field decouples from gravity
and we recover the usual Wheeler - de Witt equation of quantum gravity.Comment: LaTeX file, 24 page
Chiral Sigma Model with Pion Mean Field in Finite Nuclei
The properties of infinite matter and finite nuclei are studied by using the
chiral sigma model in the framework of the relativistic mean field theory. We
reconstruct an extended chiral sigma model in which the omega meson mass is
generated dynamically by the sigma condensation in the vacuum in the same way
as the nucleon mass. All the parameters of chiral sigma model are essentially
fixed from the hadron properties in the free space. In nuclear matter, the
saturation property comes out right, but the incompressibility is too large and
the scalar and vector potentials are about a half of the phenomenological ones,
respectively. This fact is reflected to the properties of finite nuclei. We
calculate N = Z even-even mass nuclei between N = 16 and N = 34. The extended
chiral sigma model without the pion mean field leads to the result that the
magic number appears at N = 18 instead of N = 20 and the magic number does not
appear at N = 28 due to the above mentioned nuclear matter properties. The
latter problem, however, could be removed by the introduction of the finite
pion mean field with the appearance of the magic number at N = 28. We find that
the energy differences between the spin-orbit partners are reproduced by the
finite pion mean field which is completely a different mechanism from the
standard spin-orbit interaction.Comment: 19 pages, 9 figures. Prog. Theor. Phys. to be publishe
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