Au, Ge, and AuGe nanoparticles fabricated by laser ablation

A eutectic AuGe target immersed in distilled water was ablated by pulsed ultraviolet laser light. The structure of the ablated material was investigated by high-resolution transmission electron microscopy (HRTEM). The images show formation of nanowire structures of AuGe up to 100 nm in length, with widths of 5–10 nm. These nanostructures have Ge content significantly lower than the target material. Electron diffraction demonstrates that they crystallize in the α-AuGe structure. For comparison, laser ablation of pure Au and pure Ge targets was also performed under the same conditions. HRTEM shows that Ge forms spherical nanoparticles with a characteristic size of ~30 nm. Au forms spherical nanoparticles with diameters of ~10 nm. Similar to AuGe, it also forms chainlike structures with substantially lower aspect ratio.     

Local convergence of quasi-Newton methods for B-differentiable equations

We study local convergence of quasi-Newton methods for solving systems of nonlinear equations defined by B-differentiable functions. We extend the classical linear and superlinear convergence results for general quasi-Newton methods as well as for Broyden's method. We also show how Broyden's method may be applied to nonlinear complementarity problems and illustrate its computational performance on two small examples.     

The synthesis of the africane-type sesquiterpenoid, 1,5,8,8-tetramethyl-tricyclo[8,1,0,02,6]undec-5-en-9-ol-4-one

One of the alcohols derived from rearrangement of humulene-4,5-epoxide has been converted into a keto-alcohol, the angelate ester of which is a naturally-occurring sesquiterpenoid.     

A nontrivial vacuum state in D = 10, N = 1 supergravity

We find a ground state of D = 10, N = 1 supergravity of the form (AdS(3) × R¹) × S³ × T³ which preserves all supersymmetries and should provide a gauged D = 4, N = 4 supergravity coupled to supermatter after dimensional reduction.     

Quarks and the helicity structure of photoproduction amplitudes

Algebraic properties of the transformation between constituent and current quarks are used to derive the helicity structure of photoproduction matrix elements.     

Olefination of alpha-hydroxy or alpha-aminoaldehyde derivatives via reaction of their arylsulfonylhydrazones with sulfonyl anions

Reaction of tosylhydrazones of O-substituted alpha-hydroxy or N-substituted alpha-amino aldehydes (2, 7, 11, 15, 17, and 20) with selected alpha-magnesio alkyl phenyl sulfones afforded the respective derivatives of allylic alcohols or allylic amines. 2,3-O-Isopropylidene-D-glyceraldehyde (1) was transformed into its tosylhydrazone (2) and then olefins 4a with retention of optical purity.     

Determination of T1-spin-lattice relaxation time in a two-level system by continuous wave multiquantum electron paramagnetic resonance spectroscopy in a presence of tetrachromatic microwave irradiation

Applicability of continuous wave multiquantum EPR methods to study relaxation times at X-band is examined. Multiquantum transitions excited in a two-level system by tetrachromatic irradiation are used for these studies. The Bloch equation model is applied to simulate lineshapes of the three quantum transitions as a function of frequency difference between exciting fields. The dependence of multiquantum transition signals on relaxation times and microwave amplitude is shown. On this basis a method of deducing relaxation times from these signals is formulated. The case of a homogeneously and inhomogeneously broadened resonance line is considered. Two experimental methods are used to verify the proposed hypothesis: the X-band continuous wave multiquantum EPR with four frequencies microwave field and saturation recovery EPR. The values of T₁ obtained from CW MQ EPR and SR EPR are compared.     

Size versus volume extensivity of a new class of density matrix functionals

Despite being size-extensive, the "second-generation" 1-matrix functionals for the electron-electron repulsion energy V(ee) yield vanishing correlation energy for the homogeneous electron gas. This failure is directly related to the idempotency condition imposed upon an auxiliary matrix that enters the expression for V(ee). In particular, the recently proposed Kollmar-Hess functional is not volume-extensive and thus is incapable of properly describing any delocalized system at its thermodynamic limit.