Additive twists of Fourier coefficients of symmetric-square lifts

We study the sum of additively twisted Fourier coefficients of a symmetric-square lift of a Maass form invariant under the full modular group. Our bounds are uniform in terms of the spectral parameter of the Maass form, as well as in terms of the additive twist.     

Z-scan analysis and ab initio studies of β-BaTeMo2O9 single crystal

The Z-scan measurements for the non-centrosymmetric optical crystals β-BaTeMo₂O₉ (BTMO) were performed. The corresponding experiments were carried out using the 5 ns pulses of the second harmonic of a nanosecond Nd:YAG laser at the 532 nm wavelength. It was shown that the studied crystals possess promising third-order optical susceptibilities, which allow to use the crystal as optical limiters. The comparison with other oxide materials is presented. To clarify the origin of the observed effect, the electronic and optical properties of BTMO were calculated using the density functional theory (DFT)-based method. The performed calculations of the electronic and optical properties revealed certain peculiar features that can be suitable for the nonlinear optical applications. The relation between the observed nonlinear optical features and the calculated band structure is emphasized. The values of the calculated band gap and refractive index for β-BaTeMo₂O₉ are also reported.     

Preferential Interactions on Polystyrene Divinylbenzene Copolymeric Sorbents

The adsorption of picric acid, naphthalene-sulfonic acid, and toluenesulfonic acid onto a polystyrene divinylbenzene copolymeric sorbent in methanol-water systems at 25°C was studied by reverse-phase high performance liquid chromatography. The observed peak asymmetry and increase in capacity factor at high methanol concentrations in the mixture was attributed to preferential interactions of the solutes at the surface. The phenomena were not as pronounced for octadecyl silane bonded phases.     

Characterizing polymer macrostructures by identifying and locating microstructures along their chains with the kerr effect

In this brief report, we demonstrate that Kerr effect measurements, which determine the excess birefringence contributed by polymer solutes in dilute solutions observed under a strong electric field, are highly sensitive to and capable of determining their microstructures, as well as their locations along the macromolecular backbone. Specifically, using atactic triblock copolymers with the same overall composition of styrene (S) and p-bromostyrene (pBrS) units, but with two different block arrangements, that is, pBrS₉₀-b-S₁₂₀-b-pBrS₉₀ (I) and S₆₀-b-pBrS₁₈₀-b-S₆₀ (II), which are indistinguishable by NMR, we detected a dramatic difference in their molar Kerr constants (_mK), in agreement with those previously estimated. Although similar in magnitude, their Kerr constants differ in sign, with _mK(II) positive and _mK(I) negative. In addition, S/pBrS random and gradient copolymers synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization exhibit a heretofore unexpected enhanced enchainment of racemic (r) pBrS-pBrS diads. Comparison of their observed and calculated _mKs suggests that the gradient S/pBrS copolymers possess an unanticipated additional gradient in stereosequence that parallels their comonomer gradient, that is, as the concentration of pBrs units decreases from one end of the copolymer chain to the other, so does the content of r diads. This conclusion could only be reached by comparison of observed and calculated Kerr effects, which access the global properties of macromolecules, and not NMR, which is only sensitive to local polymer structural environments, but not to their locations on the copolymer chains. Molar Kerr constants are characteristic of entire polymer chains and are highly sensitive to their constituent microstructures and their distribution along the chain. They may be used to both identify constituent microstructures and locate them along the polymer chain, thereby enabling, for the first time, characterization of their complete macrostructures. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Reconstruction of physics objects at the Circular Electron Positron Collider with Arbor

After the Higgs discovery, precise measurements of the Higgs properties and the electroweak observables become vital for the experimental particle physics. A powerful Higgs/Z factory, the Circular Electron Positron Collider (CEPC) is proposed. The Particle Flow oriented detector design is proposed to the CEPC and a Particle Flow algorithm, Arbor is optimized accordingly. We summarize the physics object reconstruction performance of the Particle Flow oriented detector design with Arbor algorithm and conclude that this combination fulfills the physics requirement of CEPC.     

Molecular dynamics study on the thermal conductivity and mechanical properties of boron doped graphene

We investigated the effects of boron atoms substitution on the thermal conductivity and mechanical properties of single-layer graphene using the non-equilibrium molecular dynamics (NEMD) simulations. By performing the uniaxial tension simulations, we observed that substituted boron atoms slightly decrease the elastic modulus and tensile strength of graphene. On the other hand, it was observed that only 0.75% concentration of boron atoms in graphene reduces the thermal conductivity of graphene by more than 60% and leads to vanishing chirality effect.     

Force constants and normal vibrations of the haloacetonitriles

Normal coordinate calculations were carried out for fluoro-, chloro-, bromo- and iodoacetonitrile, using a seventeen-parameter valence force field. Most of the force constants have different values in the four halides that change in a regular manner. The a″ vibrations are essentially pure, but there is considerable mixing of normal modes in the a′ species. The difference in previous vibrational assignments is resolved but the bands assigned to the C-C-Br and C-C-I bends were found to be mainly C-Br and C-I stretching vibrations. Transferability of the force constants obtained for the CH₂Cl group seems quite good.