Photoinduced spontaneous and stimulated emission in sexithiophene single crystals

Temperature dependent steady-state and transient photoluminescence (PL) measurements were carried out on sexithiophene (6T) single crystals. As the temperature is lowered, three different sets of equally spaced peaks appear on the steady state PL spectrum. This behavior is interpreted in the frame of the molecular exciton theory. The first energy set is attributed to transitions to the lower level of the Davydov splitting of the 1B_u excited state of the isolated molecule, whereas the two other sets are ascribed to the crystal defects. An analysis of the PL emission and excitation spectra allowed us to establish a general exciton energy scheme of sexithiophene crystal. At low excitation levels, the transient PL follows a single exponential decay, with a decay time of 1.8 ± 01 ns. When the excitation energy is increased, a second, much faster component is added. Concurrently, the PL spectrum narrows to a single line centered at the origin of the low energy set of the steady state PL. The width of the emission line is 13 cm⁻¹ at 10 K, and tends to widen and shift towards lower energies when the temperature is raised. All these observations are accounted for in term of stimulated emission.     

Medullary swallowing-related neurons in the anesthetized cat

Swallowing-related neurons (SRNs) were recorded systematically in the medulla oblongata of urethane-anesthetized cats. The SRNs received orthodromic inputs from the superior laryngeal nerve (SLN) and showed transient changes in their activity synchronous with swallowing. These neurons could be divided into three types. Type I SRNs are sensory-relay neurons from the SLN in the nucleus of the tractus solitarius (NTS), type II are interneurons located diffusely in the parvocellular reticular formation ventral to the NTS, which received oligosynaptic inputs from the SLN, and type III are motoneurons in the nucleus ambiguus. Some type II neurons still showed the swallowing activity after the animals were paralysed, which suggests that they could be involved in the generation of swallowing outputs.     

Threshold-Voltage Control of AC Performance Degradation-Free FD SOI MOSFET With Extremely Thin BOX Using Variable Body-Factor Scheme

The bias scheme of the variable body-factor fully depleted (FD) silicon-on-insulator (SOI) MOSFET, which has been previously proposed, is reexamined. Using a new scheme, the inversion and accumulation on the substrate in the active state can be avoided, and thus, ac performance in the active state is not degraded even with extremely thin buried-oxide (BOX), owing to the depletion of the substrate. Moreover, subthreshold leakage can be sufficiently suppressed in the standby state, owing to extremely thin BOX. This scheme provides threshold-voltage adjustability for the suppression of interdie and within-die variation in the active state. This device scheme is also applicable to multichannel FD SOI MOSFETs including FinFETs with a low-aspect-ratio fin, where the back-bias scheme can be applied     

Fatty acid and essential oil composition of three Tunisian caraway (Carum carvi L.) seed ecotypes

BACKGROUND: The essential oil and fatty acid composition of Tunisian annual caraway (Carum carvi L.) seeds from three ecotypes was investigated by gas chromatography and gas chromatography–mass spectrometry analyses. RESULTS: Total fatty acid (TFA) proportion of caraway seeds varied from 2.95% to 5.68% (w/w). The fatty acid composition revealed that Tunisian caraway seed oil is rich in an unusual fatty acid—petroselinic acid—the proportion of which varied from 31.53% and 38.36% of TFA. Essential oil yields were relatively low and ranged from 0.86% to 1.20% (w/w). Forty‐one volatile compounds were identified, the main ones being carvone (76.78–80.53%) and limonene (13.05–20.29%). CONCLUSION: Tunisian caraway seed oil is rich in an unusual fatty acid—petroselinic acid—which is of potential industrial significance. In addition, Tunisian caraway essential oil is carvone chemotype. This fact is of great economic interest due to the several applications of carvone in the alimentary and medicinal industries. Copyright © 2009 Society of Chemical Industry     

Deadbeat flux level control of direct-field-oriented induction motor

A method for the deadbeat flux level control of a direct-field-oriented induction motor with position control loop has been developed that employs an adaptive rotor flux observer. The observer is a full-order type and is used not only in the direct-field-oriented controller, but also to identify stator and rotor resistances of the motor. The observer reduces the sensitivity of a deadbeat controller to fluctuations in the motor parameters. The main advantage of this method is that it improves the efficiency of an induction motor without sacrificing dynamic performance. This paper describes the method as well as the fundamental characteristics of the system derived from experimental and simulation results.     

A mixed spectral-domain approach for dispersion analysis ofsuspended planar transmission lines with pedestals

A mixed spectral-domain analysis is used to derive dispersion characteristics of domain modes in a class of planar transmission lines with a pedestal. Equivalent structures are constructed in which magnetic surface currents are identified as the unknowns at the aperture separating two different regions. Spectral dyadic Green's functions are derived for these structures using the spectral-domain immittance approach. The characteristic equations resulting from the application of the spectral Galerkin method involve mixing two different spectral domains, which exist on the two sides of the pedestal support. The present method allows one to retain the simplicity and numerical efficiency of the conventional spectral-domain immittance approach, which cannot be applied directly to the present structures. Numerical data are provided for the dispersion characteristics of dominant modes in a pedestal-supported stripline and finline