Non critical super strings on world sheets of constant curvature

We consider correlation functions in Neveu-Schwarz string theory coupled to two dimensional gravity. The actionfor the 2D gravity consists of the string induced Liouville action and the Jackiw-Teitelboim action describing pure 2D gravity. Then gravitational dressed dimensions of vertex operators are equal to their bare conformal dimensions. There are two possible interpretations of the model. Considering the 2D dilaton and the Liouville field as additional target space coordinates one gets ad+2-dimensional critical string. In thed-dimensional non critical string picture gravitational fields retain their original meaning and ford=4 one can get a mass spectrum via consistency requirements. In both cases a GSO projection is possible.     

Phase determination in interference-based superresolving microscopes through critical frequency analysis

Utilizing the interference of wave fronts of two opposing lenses, 4Pi-confocal and I(5)M microscopy improve the axial resolution of far-field fluorescence microscopy as much as threefold to sevenfold. However, establishing the phase difference of the wave fronts in the sample is a problem yet to be solved. Here we show that the phase difference is encoded in the microscope's transfer of the spatial frequencies that match the distance of the interference peaks. As a result the phase difference is readily extracted through a Fourier transform of the image. Our method is relevant to all microscopes that exploit the interference of counterpropagating waves to improve the axial and the lateral resolution.     

Sulphur and oxygen isotopic characters of dissolved sulphate in groundwater from the Pleistocene aquifer in the southern Jordan Valley (Jericho area,Palestine)

Sulphate and chloride concentrations in the shallow Pleistocene aquifer systems in the lower Jordan valley area indicate a general trend of increasing salinity eastward and southward. This study was conducted in one of the important sub-basins feeding the Pleo–Pleistocene aquifer in the Jericho area in the southern part of the valley using S and O isotopes of dissolved sulphate. The results show that sulphate has mainly two contributions to the groundwater. One is the surface seepage, which is present as a salty leachate form with the positive δ³⁴S_sulphate values of primary gypsum in Lisan and Samara formations, and the second is the upwelling saline water which was in contact with a deep secondary gypsum, aragonites and salty rocks and rose up under heavy abstraction with depleted ³⁴S in sulphate and relatively high sulphate and chloride content. The latest was clearly shown in the Arab Project wells to the east that is undergoing a continuous heavy abstraction. The isotopic signatures of S and O in these wells to the east show that this depleted ³⁴S and highly concentrated sulphate might also indicate a dissolved sulphate originating from pyrite oxidation that results from the interaction with a pyrite-rich aquifer, which can well up with salty water under heavy abstraction and is oxidised in the upper aerobic shallow aquifer.     

The Formation of Pd Nanocrystals from Pd2(dba)3 Microcrystals

As‐grown platelets formed from tris‐(dibenzylideneacetone) dipalladium(0) [Pd₂(dba)₃] precursor in the presence of Pd17 RNA are investigated before and after thermal annealing. Results show that as‐grown platelets are disordered crystals of Pd₂(dba)₃ containing 1?2 nm Pd clusters and platelets grown in the absence of RNA are morphologically and structurally similar to those formed with RNA. The initially formed crystals are so sensitive to environmental variables that the degree of crystallinity can not be determined accurately by electron diffraction. X‐ray crystallography on as‐grown platelets gives a crystal structure consistent with Pd₂(dba)₃, but reveals a composition of ≈Pd_1.07(dba)₃, indicating one Pd atom in Pd₂(dba)₃ is lost from the structure. Both electron beam and thermally induced decomposition of as‐grown Pd₂(dba)₃ platelets having a hexagonal habit on the micrometer scale produces elemental Pd platelets having a hexagonal habit on the nanometer scale. These hexagonal platelets are composed of a partially sparse form of Pd₂(dba)₃ that is initially crystalline but rapidly degrades due to the loss of Pd atoms from organic ligand cages. Once released, Pd atoms aggregate to form Pd clusters, which grow and transform into well‐formed Pd nanocrystals under electron‐beam irradiation or through thermal annealing.     

Two-proton correlations in the target fragmentation region of nuclear collisions at 200A GeV

Correlations between protons are studied in the target fragmentation region of reactions of protons and¹⁶O with C, Cu, Ag, Au and of³²S with Al and Au at 200A GeV. The emitted protons were measured with the Plastic Ball detector in the WA80 experiment at the CERN SPS. The comparison of the correlation function with calculations, assuming a spherical, gaussian shaped source with a lifetime τ=0 fm/c, allows the extraction of radius parameters. The values are very close to those expected from the geometry of the target nuclei and increase with the target mass as αA _Target ^1/3 . Even in proton induced reactions the whole target nucleus is involved. The dependence of the radii on centrality, polar angleθ _lab, and energy, and their relation to measured proton yields are presented.     

Microstructural characterization of Li insertion in individual silicon nanowires

The lithiation and delithiation process of silicon nanowire arrays (SiNWs) on silicon substrates has been studied with high-resolution electron microscopy. The composition of lithiated SiNWs was revealed, consisting of the unreacted crystalline silicon core and the reacted amorphous Li–Si shell. In particular, the Li–Si shell was comprised of a mixture of amorphous silicon oxide and crystalline silicon, leading to hindrance during Li–Si alloying/dealloying upon cycling.     

Multi-jet events in the k T -factorisation scheme

A Markovian Monte Carlo algorithm for multi-parton production in the high-energy limit is proposed and the matching with unintegrated parton densities is discussed.