Theory of Thermodynamic Magnetic Oscillations in Quasi-One-Dimensional Conductors

The second order correction to free energy due to the interaction between electrons is calculated for a quasi-one-dimensional conductor exposed to a magnetic field perpendicular to the chains. It is found that specific heat, magnetization and torque oscillate when the magnetic field is rotated in the plane perpendicular to the chains or when the magnitude of magnetic filed is changed. This new mechanism of thermodynamic magnetic oscillations in metals, which is not related to the presence of any closed electron orbits, is applied to explain behavior of the organic conductor (TMTSF)$_2$ClO$_4$.Comment: 11 pages + 5 figures (included

Magneto-oscillations in the high-magnetic-field state of (TMTSF)(2)ClO4

We report a systematic study of the anomalous rapid oscillation (RO) phenomena in the quasi-one-dimensional organic metal (TMTSF)(2)ClO4 in pulsed magnetic fields up to 51 T. We argue that the temperature and magnetic-field dependence of the RO amplitudes in the high-field state result from the reconstructed, nested Fermi surface topology at low temperatures in high magnetic fields. In this topology, the RO amplitudes depend on competing magnetic breakdown and Bragg reflection probabilities, along with Lifshitz-Kosevich reduction factors

Dispositif de compensation pour la mise en évidence d'effets oscillatoires de la magnétorésistance en champ magnétique pulsé

A device is described which allows us to keep out the monotonic part of the magnetoresistance near oscillations, when using a pulsed high magnetic field with exponential decay.Un dispositif électronique permet d'éliminer la partie monotone de la magnétorésistance au voisinage d'oscillations, pour des mesures effectuées à l'aide d'un champ magnétique pulsé à décroissance exponentielle

Dispositif de compensation pour la mise en évidence d'effets oscillatoires de la magnétorésistance en champ magnétique pulsé

Un dispositif électronique permet d'éliminer la partie monotone de la magnétorésistance au voisinage d'oscillations, pour des mesures effectuées à l'aide d'un champ magnétique pulsé à décroissance exponentielle

FIRST OBSERVATION OF WEAK LOCALIZATION EFFECTS IN ORGANIC CONDUCTORS ?

We have studied the transverse magnetoresistance of the organic series (DMtTSF)2 X down to 2 K and up to 40 T. Under about 20 K and 8 T a negative magnetoresistance appears only for salts whose X is a tetrahedral anion. This new phenomenon is interpreted as a two-dimensional (2D) weak localization effect

Regulated and Unregulated Exhaust Emissions Comparison for Three Tier II Non-Road Diesel Engines Operating on Ethanol-Diesel Blends

Regulated and unregulated emissions (individual hydrocarbons, ethanol, aldehydes and ketones, polynuclear aromatic hydrocarbons (PAH), nitro-PAH, and soluble organic fraction of particulate matter) were characterized in engines utilizing duplicate ISO 8178-C1 eight-mode tests and FTP smoke tests. Certification No. 2 diesel (400 ppm sulfur) and three ethanol/diesel blends, containing 7.7 percent, 10 percent, and 15 percent ethanol, respectively, were used. The three, Tier II, off-road engines were 6.8-L, 8.1-L, and 12.5-L in displacement and each had differing fuel injection system designs. It was found that smoke and particulate matter emissions decreased with increasing ethanol content. Changes to the emissions of carbon monoxide and oxides of nitrogen varied with engine design, with some increases and some decreases. As expected, increasing ethanol concentration led to higher emissions of acetaldehyde (increases ranging from 27 to 139 percent). Benzene emissions were reduced by up to 50 percent with the ethanol-blended fuels. Emissions of 1,3-butadiene were also substantially decreased, with reductions ranging from 24 to 82 percent. Isolated trends were noted for certain PAHs. There was a decrease in 1-nitropyrene with use of ethanol in all cases. Particulate phase 1-nitropyrene was reduced from 18 to 62 percent. There was also a general increase in the proportion of heavy PAHs in the particulate phase with ethanol use, and although less pronounced, a general decrease in light PAHs in the particulate phase