Recent results at LULI on fast electron transport with and without guiding cone in the context of fast ignitor

We present experimental and numerical results obtained at LULI (Laboratoire pour l’Utilisation des Lasers intenses) on propagation and energy deposition of laser-generated fast electrons into conical targets. The experimental measurements were performed by means of several diagnostics in order to assess the predicted benefit of conical targets over standard planar ones. Various configurations have been tried, regarding the laser parameters with the aim of optimizing the laser-to-target coupling. Our best results have been obtained when the laser was frequency-doubled at 0.53 μm, corresponding to interaction conditions without laser pedestal due to the ASE (Amplified Spontaneous Emission). Our data pinpoint the detrimental influence of the pre-plasma generated by the laser pedestal at 1.057 μm, whose confinement is enhanced in conical geometry as evidenced by shadowgraphic measurements which is also confirmed by 2D Cu-Ka transverse images obtained from Cu cones. The consequence is the filling of the cone, preventing the laser beam from efficiently reaching the cone tip. These experimental results are compared to 2D PIC simulations modeling of the laser-cone interaction.     

Time Invariance as an Additional Constraint on Nonlocal Realism

We assume that time invariance of physical laws is true. We assume that one source of 2N uncorrelated spin-carrying particles emits them in a state, which can be described as a multipartite pure uncorrelated state (+∞>N≥1). We assume that each of them is a spin-1/2 pure state lying in the \(\frac{z+x}{\sqrt{2}}\) direction. We assume that the measurement setup is two-orthogonal-settings for each of the observers. We show that 2N-particle pure uncorrelated quantum state violates a time invariant nonlocal realistic theory. 2N implies that we consider Bose-Einstein statistics.     

Synchrotron radiation photoelectron spectroscopy and near-edge X-ray absorption fine structure study on oxidative etching of diamond-like carbon films by hyperthermal atomic oxygen

Surface structural changes of a hydrogenated diamond-like carbon (DLC) film exposed to a hyperthermal atomic oxygen beam were investigated by Rutherford backscattering spectroscopy (RBS), synchrotron radiation photoelectron spectroscopy (SR-PES), and near-edge X-ray absorption fine structure (NEXAFS). It was confirmed that the DLC surface was oxidized and etched by high-energy collisions of atomic oxygen. RBS and real-time mass-loss data showed a linear relationship between etching and atomic oxygen fluence. SR-PES data suggested that the oxide layer was restricted to the topmost surface of the DLC film. NEXAFS data were interpreted to mean that the sp² structure at the DLC surface was selectively etched by collisions with hyperthermal atomic oxygen, and an sp³-rich region remained at the topmost DLC surface. The formation of an sp³-rich layer at the DLC surface led to surface roughening and a reduced erosion yield relative to the pristine DLC surface.     

Wilsonian RG Analysis of the P-wave Nucleon–Nucleon Scattering Including Pions

We perform a Wilsonian renormalization group analysis for the nucleon–nucleon scattering in the P waves in the nuclear effective field theory including pions, in a similar way to the one done for the S-waves in our previous paper. We emphasize that the one-pion exchange interaction with large momentum transfer is of the same order as the leading contact interaction, so that there is no mismatch of the power counting. It is explicitly shown by obtaining consistent sets of renormalization group equations, that the cutoff dependence generated by the loop diagrams containing pion exchanges can be compensated by the cutoff dependence of the coupling constants of the contact interactions.     

High-performance optical code generation and recognition by use of a 511-chip, 640-Gchip/s phase-shifted superstructured fiber Bragg grating

The generation and recognition of a record-length 511-chip optical code is experimentally demonstrated by use of a superstructured fiber Bragg grating (SSFBG) with a chip rate of 640 Gchips/s. Very high reflectivity (92%) is achieved with high-quality correlation properties. The temperature deviation tolerance is approximately +/- 0.3 degrees C, which is within the package's temperature stability range (+/- 0.1 degrees C). Experimental results show good agreement with the theory. They indicate the SSFBG's potential for processing a long optical code with an ultrahigh chip rate, which could significantly improve the system's performance.     

A complete calculation for direct detection of Wino dark matter

In the anomaly-mediated supersymmetry (SUSY) breaking scenario, neutral gaugino of SUL₍₂₎$\mathit{SU}{(2)}_L$ multiplet, Wino, can be the lightest SUSY particle and become a candidate for dark matter. We calculated scattering cross section of Wino dark matter with nucleon, which is responsible for direct detection of the dark matter, on the assumption that the SUSY particles and the heavier Higgs bosons have masses of the order of the gravitino mass in the SUSY standard model. In such a case, the Wino–nucleon coupling is generated by loop processes. We have included two-loop contribution to Wino–gluon interaction in the calculation, since it is one of the leading contributions to the Wino–nucleon coupling. It was found that the spin-independent scattering cross section with proton is ^{10−(46–48)} cm²${10}^{-(46\text{–}48)}{\text{cm}}^2$. While it is almost independent of the Wino mass, the result is quite sensitive to the Higgs boson mass due to the accidental cancellation.     

A CO Adsorption Site Change Induced by Copper Substitution in a Ruthenium Catalyst for Enhanced CO Oxidation Activity

Ru is an important catalyst in many types of reactions. Specifically, Ru is well known as the best monometallic catalyst for oxidation of carbon monoxide (CO) and has been practically used in residential fuel cell systems. However, Ru is a minor metal, and the supply risk often causes violent fluctuations in the price of Ru. Performance‐improved and cost‐reduced solid‐solution alloy nanoparticles of the Cu‐Ru system for CO oxidation are now presented. Over the whole composition range, all of the Cu_xRu_1?x nanoparticles exhibit significantly enhanced CO oxidation activities, even at 70 at % of inexpensive Cu, compared to Ru nanoparticles. Only 5 at % replacement of Ru with Cu provided much better CO oxidation activity, and the maximum activity was achieved by 20 at % replacement of Ru by Cu. The origin of the high catalytic performance was found as CO site change by Cu substitution, which was investigated using in situ Fourier transform infrared spectra and theoretical calculations.     

Preparation of the TiO2 Thin Film Photocatalyst by the Dip-Coating Process

Titanium dioxide (TiO2) coated glass-plate thin film photocatalysts for elimination of air pollutants, were prepared by the dip-coating process with titanium alkoxide including polyethylene glycol (PEG). The surface structure of these thin films changed drastically with the size of the PEG. They were either transparent or opaque. Nitrogen oxides (NOx), one of the most hazardous of air pollutants, were found to be efficiently eliminated by the thin film photocatalyst. The photocatalytic activities of the transparent and opaque thin films were found to be almost equal. This may be due to the two films having the same surface area. The highest activity was obtained for thin films around 1 m.     

Synthesis, Characterization, and Crystal Structure of a (&mgr;-Oxo)bis(&mgr;-acetato)diiron(III) Complex with a Dinucleating Hexapyridine Ligand, 1,2-Bis[2-(bis(2-pyridyl)methyl)-6-pyridyl]ethane. The First Example of a Discrete (&mgr;-Oxo)bis(&mgr;-acetato)diiron(III) Complex with a Dinucleating Ligand

A mononucleating tripyridine ligand, 2-(bis(2-pyridyl)methyl)-6-methylpyridine (L(1)), and a dinucleating hexapyridine ligand, 1,2-bis[2-(bis(2-pyridyl)methyl)-6-pyridyl]ethane (L(2)), have been prepared. The reaction of a carbanion of 2,6-lutidine with 2-bromopyridine affords L(1) which is converted to L(2) quantitatively by treating with tert-butyllithium and 1,2-dibromoethane. (&mgr;-Oxo)bis(&mgr;-acetato)diiron(III) complexes [Fe(2)(O)(OAc)(2)(L(1))(2)](ClO(4))(2) (1) and [Fe(2)(O)(OAc)(2)L(2)](ClO(4))(2) (2) have been synthesized and characterized by means of infrared, UV/vis, mass, and M?ssbauer spectroscopies and by measuring magnetic susceptibility and cyclic voltammograms. All the spectral data are consistent with the (&mgr;-oxo)bis(&mgr;-acetato)diiron(III) core structure in both 1 and 2. A relatively strong molecular ion peak at m/z 865 corresponding to [{Fe(2)O(OAc)(2)L(2)}(ClO(4))](+) in a FAB mass spectrum of 2 suggests the stabilization of the (&mgr;-oxo)bis(&mgr;-acetato)diiron(III) core structure by L(2) in a solution state. The compound 2.DMF.2-PrOH.H(2)O, chemical formula C(44)Cl(2)Fe(2)H(51)N(7)O(16), crystallizes in the monoclinic space group C2/c with a = 22.034(6) ?, b = 12.595(5) ?, c = 20.651(7) ?, beta = 121.49(2) degrees, and Z = 4. The cation has 2-fold symmetry with the bridging oxygen atom on the 2-fold axis: Fe-(&mgr;-O) = 1.782(5) ?, Fe-O-Fe = 123.6(6) degrees, and Fe.Fe = 3.142(3) ?. The diiron(III) core structure of 2 seems to be stabilized by encapsulation of the ligand. Compound 2 is the first example of a discrete (&mgr;-oxo)bis(&mgr;-acetato)diiron(III) complex with a dinucleating ligand.     

Synthesis of microspheres with microphase‐separated shells

Novel structural microspheres of the Janus type, with microphase‐separated polystyrene (PS) and poly(tert‐butyl methacrylate) (PBMA) shells and crosslinked poly(2‐vinyl pyridine) (PVP) cores, were synthesized with the crosslinking of PVP spherical domains in poly(styrene‐block‐2‐vinyl pyridine‐block‐tert‐butyl methacrylate) ABC triblock terpolymer film with PS/PBMA lamellae–PVP spherical structures. For the formation of lamellae‐sphere structures, toluene, which was a selective solvent for the ABC triblock terpolymer, was used. With the crosslinking of PVP spheres in the microphase‐separated film with 1,4‐diiodobutane gas, the microphase structure of the terpolymer was fixed, and microspheres composed of microphase‐separated PS and PBMA shells and P2VP cores were obtained. The size distribution of the purified microspheres was narrow. The characteristics of the microspheres and their aggregation behaviors in selective solvents were investigated by transmission electron microscopy and light scattering methods. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2091–2097, 2000