Phase transformation of Ni-B, Ni-P diffusion barrier deposited electrolessly on Cu interconnect

In this paper, we report that the phase transformation of Ni-B, Ni-P diffusion barriers deposited electrolessly on Cu, for the reason that the Ni-P layer is a more effective diffusion barrier than the Ni-B layer. The Ni₃B crystallized was decomposed to Ni and B₂O₃ above 400 °C and the Ni₃P crystallized was decomposed to Ni and P₂O₅ above 600 °C respectively in Ar atmosphere. Also, the Ni₃B was decomposed to Ni and free B above 400 °C and the Ni₃P was decomposed to Ni and free P above 600 °C respectively in H₂ atmosphere. The decomposed Ni formed a solid solution with Cu. The Cu diffusion occurred above 400 °C for Ni-B layer and above 600 °C for Ni-P layer, respectively. Because the decomposition temperature of Ni-P layer is about 200 °C higher than that of Ni-B layer, the Ni-P layer is a more effective barrier for Cu than the Ni-B layer.     

Simplifying equations in Arabic algebra

Historians have always seen jabr (restoration) and muqābala (confrontation) as technical terms for specific operations in Arabic algebra. This assumption clashes with the fact that the words were used in a variety of contexts. By examining the different uses of jabr, muqābala, ikmāl (completion), and radd (returning) in the worked-out problems of several medieval mathematics texts, we show that they are really nontechnical words used to name the immediate goals of particular steps. We also find that the phrase al-jabr wa'l-muqābala was first used within the solutions of problems to mean al-jabr and/or al-muqābala, and from there it became the name of the art of algebra.     

An Enumerative Geometry for Magic and Magilatin Labellings

A magic labelling of a set system is a labelling of its points by distinct positive integers so that every set of the system has the same sum, the magic sum. Examples are magic squares (the sets are the rows, columns, and diagonals) and semimagic squares (the same, but without the diagonals). A magilatin labelling is like a magic labelling but the values need be distinct only within each set. We show that the number of n × n magic or magilatin labellings is a quasipolynomial function of the magic sum, and also of an upper bound on the entries in the square. Our results differ from previous ones because we require that the entries in the square all be different from each other, and because we derive our results not by ad hoc reasoning but from a general theory of counting lattice points in rational inside-out polytopes. We also generalize from set systems to rational linear forms. Dedicated to the memory of Claudia Zaslavsky, 1917–2006 Received August 10, 2005     

Coupled perpendicular magnetization in Fe/Cu/Fe trilayers

Ultrathin epitaxial Fe films on Cu(1 0 0) with perpendicular magnetization have been used as templates for the preparation of FCC Fe/Cu/Fe trilayers. The magnetic anisotropy and the coupling of these films have been studied by in-situ magneto optical Kerr effect measurements and Kerr microscopy. The magnetic coupling of both Fe layers is found to be dominated by magnetostatic interaction. Adsorbate-induced spin reorientation in the top layer also causes spin reorientation in the bottom layer. The governing role of the Fe-vacuum interface for the magnetism of the whole trilayer is demonstrated.     

Quadrupole interactions at 57Fe and 119Sn in 3d-metal antimonides

3d-metal antimonides: Fe_1+x Sb, N_+x Sb, Co_+x Sb and the (Ni_1?y Fe _y )Sb solid solution have been studied by the Mössbauer effect method at ⁵⁷Fe and ¹¹⁹Sn. It was found that the quadrupole interactions at the Fe and Sn nucleus in 3d-metal antimonides are very sensitive to the filling of different crystallographic sites with metal atoms. The metal atoms in trigonal-bipyramidal sites have a strong effect on the quadrupole splitting of ¹¹⁹Sn. They are nearest to anions (Sb or Sn) with the typical axial ratio of c/a = 1.25. The QS(x) dependence of ¹¹⁹ Sn in 3d-metal antimonides in the 0 ≤ x ≤ 0.1 concentration range can be used to determine x – the concentration of transition metal excess relative to the stoichiometric composition.     

Navier-Stokes equations in 3D thin domains with Navier friction boundary condition

In this article we study the 3D Navier-Stokes equations with Navier friction boundary condition in thin domains. We prove the global existence of strong solutions to the 3D Navier-Stokes equations when the initial data and external forces are in large sets as the thickness of the domain is small. We generalize the techniques developed to study the 3D Navier-Stokes equations in thin domains, see [G. Raugel, G. Sell, Navier-Stokes equations on thin 3D domains I: Global attractors and global regularity of solutions, J. Amer. Math. Soc. 6 (1993) 503-568; G. Raugel, G. Sell, Navier-Stokes equations on thin 3D domains II: Global regularity of spatially periodic conditions, in: Nonlinear Partial Differential Equations and Their Application, College de France Seminar, vol. XI, Longman, Harlow, 1994, pp. 205-247; R. Temam, M. Ziane, Navier-Stokes equations in three-dimensional thin domains with various boundary conditions, Adv. Differential Equations 1 (1996) 499-546; R. Temam, M. Ziane, Navier-Stokes equations in thin spherical shells, in: Optimization Methods in Partial Differential Equations, in: Contemp. Math., vol. 209, Amer. Math. Soc., Providence, RI, 1996, pp. 281-314], to the Navier friction boundary condition by introducing a new average operator Mε in the thin direction according to the spectral decomposition of the Stokes operator Aε. Our analysis hinges on the refined investigation of the eigenvalue problem corresponding to the Stokes operator Aε with Navier friction boundary condition.     

Dielectric and conduction mechanism studies of PVA-orthophosphoric acid polymer electrolyte

Polyvinyl alcohol (PVA)-based proton conducting polymer electrolytes have been prepared by the solution cast technique. The conductivity is observed to increase from 10⁻⁹ to 10⁻⁴ S cm⁻¹ as a result of orthophosphoric acid (H₃PO₄) addition. The plot of conductivity vs temperature shows that a phase transition occurred at 343 K in the sample PVA-33 wt% H₃PO₄. The β-relaxation peak is observed at 313 K. The glass transition temperature of PVA-33 wt% H₃PO₄ is 343 K. Orthophosphoric acid seems to play a dual role, i.e., as a proton source and as a plasticizer. The ac conductivity σ _ac = Aω ^s was also calculated in the temperature range from 303 to 353 K. The conduction mechanism was inferred by plotting the graph of s vs T from which the conduction mechanism for sample PVA-17 wt% H₃PO₄ was inferred to occur by way of the overlapping large polaron tunneling (OLPT) model and the conduction mechanism for the sample PVA-33 wt% H₃PO₄ by way of the correlated barrier height (CBH) model.     

Singlet versus triplet dynamics of β-carotene studied by quantum control spectroscopy

Biomolecules very often present complex energy deactivation networks with overlapping electronic absorption bands, making their study a difficult task. This can be especially true in transient absorption spectroscopy when signals from bleach, excited state absorption and stimulated emission contribute to the signal. However, quantum control spectroscopy can be used to discriminate specific electronic states of interest by applying specifically designed laser pulses. Recently, we have shown the control of energy flow in bacterial light-harvesting using shaped pump pulses in the visible and the selective population of pathways in carotenoids using an additional depletion pulse in the transient absorption technique. Here, we apply a closed-loop optimization approach to β-carotene using a spatial light modulator to decipher the energy flow network after a multiphoton excitation with a shaped ultrashort pulse in the near-IR. After excitation, two overlapping bands were detected and identified as the S₁ state and the first triplet state T₁. Using the transient absorption signal at a specific probe delay as feedback, the triplet signal could be optimized over the singlet contribution.     

Mackey Topologies and Mixed Topologies in Riesz Spaces

The possibility of characterizing the Mackey topology of a dual pair of vector spaces as a generalized inductive limit (or mixed) topology is investigated. Positive answers are given for a wide range of dual pairs of Riesz spaces (vector lattices) and non-commutative Banach function spaces (or symmetric operator spaces).     

Synthesis and cyclization of 1-arylalk-1-ene-3,5-diynylamines

An investigation of the reaction of 1-lithio-1,3-diynes, generated in situ, with nitriles has been carried out. In the case of aromatic nitriles 1-arylalk-1-ene-3,5-diynylamines are formed, which undergo dimerization and cyclization on isolation, giving 3-(alka-1,3-diynyl)-4-(alk-2-ynyl)-2,6-diarylpyridines. The effect of the nature of the substituent in the benzonitrile molecule on the selectivity of the reaction and the yield of the products has been determined. A scheme is proposed for the conversions and the structures of the intermediates have been established. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 701–710, May, 2006.