Anomalous gamma-ray multiplicity distributions-evidence for pre-equilibrium neutron emission

Multiplicity distributions and 〈E_γ〉 have been measured for the ${}^{124}\text{Sn}\text{(}{}^{40}\text{Ar}\text{, x}\text{n}\text{)}{}^{\mathrm{164?x}}\text{Er}$ reaction at E(Ar) = 161, 182, 189, 209, and 236 MeV. The data at E(Ar) = 236 MeV indicate that pre-equilibrium neutrons are emitted. These data, together with other reactions leading to Er final systems, are discussed in terms of pre-equilibrium mechanisms.     

Pairing factor and band structures in odd-A Pd nuclei

The band structures of the odd-A isotopes ¹⁰¹Pd, ¹⁰³Pd and ¹⁰⁵Pd are discussed in the framework of a core plus particle coupling model. The pairing factor (u_j² ? v_j²) contained in the effective coiupling strength is found to be responsible for the change of the $\text{5}\text{2}{}^{\mathrm{+}}\text{ΔJ = 2}$ band structure observed in ¹⁰¹Pd into a $\text{5}\text{2}{}^{\mathrm{+}}\text{ΔJ = 1}$ structure observed in the ^103,105Pd nuclei.     

Synthesis of an all-in-one molecule (for organic solar cells)

A multidomain compound with applications in the area of organic solar cells has been prepared. This all-in-one molecule compound integrates all the functionalities needed for solar cell action from light harvesting, carrier generation, and separation, to transport and contact to external electrodes. A convergent synthetic strategy with some 60 steps involving preparation of regioregular oligothiophenes, a zinc porphyrin, a bisterpyridine ruthenium(II) complex, a hetero oligo phenylenevinylene and functional end groups is described. Preliminary investigations of photovoltaic devices based on the target molecule gave values of 0.18 V, 0.0044 mA cm(-2), 29% and 0.000081% for the open circuit voltage (Voc), short circuit current (Isc), fill factor (FF), and efficiency (eta). These poor values are compared to those obtained with an oligo-3-hexylthiophene which gave values of 0.7 V, 0.046 mA cm(-2), 24.6%, and 0.0081% for the open circuit voltage (Voc), short circuit current (Isc), fill factor (FF) and efficiency (eta). This latter compound was also studied in a bulk heterojunction device with PCBM (1:1 blend) which gave values of 0.43 V, 0.45 mA cm(-2), 33.5%, and 0.063%.     

Matching-based preprocessing algorithms to the solution of saddle-point problems in large-scale nonconvex interior-point optimization

Interior-point methods are among the most efficient approaches for solving large-scale nonlinear programming problems. At the core of these methods, highly ill-conditioned symmetric saddle-point problems have to be solved. We present combinatorial methods to preprocess these matrices in order to establish more favorable numerical properties for the subsequent factorization. Our approach is based on symmetric weighted matchings and is used in a sparse direct LDL ^T factorization method where the pivoting is restricted to static supernode data structures. In addition, we will dynamically expand the supernode data structure in cases where additional fill-in helps to select better numerical pivot elements. This technique can be seen as an alternative to the more traditional threshold pivoting techniques. We demonstrate the competitiveness of this approach within an interior-point method on a large set of test problems from the CUTE and COPS sets, as well as large optimal control problems based on partial differential equations. The largest nonlinear optimization problem solved has more than 12 million variables and 6 million constraints.     

Observation of isomeric states and band structures in 107Cd

The odd-mass nucleus ¹⁰⁷Cd was investigated in the reactions ${}^{105}\text{Pd}\text{(α, 2}\text{n}\text{)}{}^{107}\text{Cd}\text{,}{}^{107}\text{Ag}\text{(d, 2}\text{n}\text{)}{}^{107}\text{Cd and}{}^{107}\text{Ag}\text{(}\text{p, n}\text{)}{}^{107}\text{Cd}$. The constructed level scheme is based on results, obtained from singles γ-ray spectra and excitation functions, from the measurements of delayed γ-rays, of γ-γ coincidences, of internal conversion electrons and of γ-ray angular distributions. Two new isomers were observed. The first one, interpreted as the $\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$ neutron state at 845.6 keV has a half-life of 67 ± 6 ns. This isomeric state is populated by a strong E2 cascade. Bands built on the other intrinsic states with spins and parities $\text{5}\text{2}{}^{\mathrm{+}}$ and $\text{7}\text{2}{}^{\mathrm{+}}$ are not strongly populated. For the second isomeric state at an excitation energy of 2679 keV a half-life of 55±4 ns was determined. This isomer is probably a three-quasiparticle state. Its configuration can be proposed as $\text{[π(}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?2}}{}_{\mathrm{8+}}\text{ν(}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{)}{}^1\text{]}{}_{\mathrm{<mtext>21</mtext><mtext>2</mtext>}}{}^{\mathrm{+}}$.     

Photoabsorption of alloys of Al with transition metals V,Fe, Ni and Cu and Pr near the AlL2,3-edge

The onset of Al 2p transitions of VAl₃, FeAl, NiAl, NiAl₃, CuAl₂, PrAl₂ and the disordered alloys VAl (16 at % Al, 28%, 41%), FeAl (11%) is shifted up to 1.1 eV. New pronounced structure develops close to the onset which for NiAl agrees with a density of states calculation by Connolly and Johnson.