Direct Measurement of the g-Factor of Composite Fermions

The activation gap $\Delta$ of the fractional quantum Hall states at constant fillings $\nu =2/3$ and 2/5 has been measured as a function of the perpendicular magnetic field $B$. A linear dependence of $\Delta$ on $B$ is observed while approaching the spin polarization transition. This feature allows a direct measurement of the $g$-factor of composite fermions which appears to be heavily renormalized by interactions and strongly sensitive to the electronic filling factor.Comment: 4 pages, 4 figures Changed content: Fokus more on g-factors (and less on other details

Interplanetary flow systems associated with cosmic ray modulation in 1977 - 1980

The hydromagnetic flow configurations associated with cosmic ray modulation in 1977 to 1980 were determined using solar wind plasma and magnetic field data from Voyagers 1 and 2 and Helios 1. The modulation was related to two types of large scale systems of flows: one containing a number of transients such as shocks, post shock flows and magnetic clouds; the other consisting primarily of a series of quasi-stationary flows following interaction regions containing a stream interface and often bounded by a forward reverse shock pair. Each of the three major episodes of cosmic ray modulation was characterized by the passage of the system of transient flows. Plateaus in the cosmic ray intensity time profile were associated with the passage of systems of corotating streams

Signatures of spin in the n=1/3 Fractional Quantum Hall Effect

The activation gap Delta of the fractional quantum Hall state at constant filling n =1/3 is measured in wide range of perpendicular magnetic field B. Despite the full spin polarization of the incompressible ground state, we observe a sharp crossover between a low-field linear dependence of Delta on B associated to spin texture excitations and a Coulomb-like behavior at large B. From the global gap-reduction we get information about the mobility edges in the fractional quantum Hall regime.Comment: 4 pages, 3 figure

Magnetic fields and flows between 1 AU and 0.3 AU during the primary mission of HELIOS 1

The recurrent flow and field patterns observed by HELIOS 1, and the relation between these patterns and coronal holes are discussed. Four types of recurrent patterns were observed: a large recurrent stream, a recurrent slow (quiet) flow, a rapidly evolving flow, and a recurrent compound stream. There recurrent streams were not stationary, for although the sources recurred at approximately the same longitudes on successive rotations, the shapes and latitudinal patterns changed from one rotation to the next. A type of magnetic field and plasma structure characterized by a low ion temperature and a high magnetic field intensity is described as well as the structures of stream boundaries between the sun at approximately 0.3 AU

Macroscopic fluctuations theory of aerogel dynamics

We consider the thermodynamic potential describing the macroscopic fluctuation of the current and local energy of a general class of Hamiltonian models including aerogels. We argue that this potential is neither analytic nor strictly convex, a property that should be expected in general but missing from models studied in the literature. This opens the possibility of describing in terms of a thermodynamic potential non-equilibrium phase transitions in a concrete physical context. This special behaviour of the thermodynamic potential is caused by the fact that the energy current is carried by particles which may have arbitrary low speed with sufficiently large probability.Comment: final versio

Estádio de desenvolvimento e superfície foliar reduzem a eficiência de chlorimuron-ethyl e glyphosate em Conyza sumatrensis.

Editores técnicos: Joseani Mesquita Antunes, Ana Lídia Variani Bonato, Márcia Barrocas Moreira Pimentel

Suscetibilidade diferencial de biótipos de Conyza sumatrensis ao herbicida chlorimuron-ethyl.

Editores técnicos: Joseani Mesquita Antunes, Ana Lídia Variani Bonato, Márcia Barrocas Moreira Pimentel

Polylactic acid as biobased binder for the production of 3D printing filaments for Ti6Al4V alloy manufacturing via bound metal deposition

In this paper, a biobased binder mainly composed of polylactic acid (PLA) was developed for the production of Ti6Al4V feedstock suitable for 3D printing via material extrusion. 3D printed samples were debound via solvent and thermal treatments and successfully sintered in reducing atmosphere obtaining dense metallic components. The designed and produced bio-binder is completely eliminated during the debinding processes leading to sintered samples showing a high densification (93–94%), with a microstructure composed of primary alpha phase with segregated beta phase at grain boundaries and having average grain size of 70 μm. 3D printed sintered samples show good mechanical properties (yield strength (σy) = 662 MPa, ultimate tensilte strength (UTS) = 743 MPa, elongation at break (εmax) = 12%, hardness = 5.15 GPa) influenced by the sintering parameters and the presence of some degree of micro-porosity in the final structure

New selection rules for resonant Raman scattering on quantum wires

The bosonisation technique is used to calculate the resonant Raman spectrum of a quantum wire with two electronic sub-bands occupied. Close to resonance, the cross section at frequencies in the region of the inter sub-band transitions shows distinct peaks in parallel polarisation of the incident and scattered light that are signature of collective higher order spin density excitations. This is in striking contrast to the conventional selection rule for non-resonant Raman scattering according to which spin modes can appear only in perpendicular polarisation. We predict a new selection rule for the excitations observed near resonance, namely that, apart from charge density excitations, only spin modes with positive group velocities can appear as peaks in the spectra in parallel configuration close to resonance. The results are consistent with all of the presently available experimental data.Comment: 7 pages, 2 figure

Efeito do glyphosate sobre parâmetros fisiológicos de Conyza sumatrensis.

Editores técnicos: Joseani Mesquita Antunes, Ana Lídia Variani Bonato, Márcia Barrocas Moreira Pimentel