Spectral shape dependence in the very strong coupling regime of Eliashberg theory

The effect of ² F() shape dependence on several physical properties of superconductors is studied at various values of the strong coupling indexT _c/ _ln . Our results indicate that the degree of shape dependence of each property is sensitive to the value ofT _c/ _ln . Generally, for the region we examine, 0.25T _c/ _ln 1.3, the dependence on shape is found to be higher than in the conventional strong coupling regimeT _c/ _ln 0.2. However, with the exception of the mass enhancement parameter , the amount of shape dependence does not increase steadily withT _c/ _ln and there appears to be regions of maximum shape sensitivity.     

Discrimination of quarry blasts and earthquakes in the vicinity of Istanbul using soft computing techniques

The purpose of this article is to demonstrate the use of feedforward neural networks (FFNNs), adaptive neural fuzzy inference systems (ANFIS), and probabilistic neural networks (PNNs) to discriminate between earthquakes and quarry blasts in Istanbul and vicinity (the Marmara region). The tectonically active Marmara region is affected by the Thrace-Eski?ehir fault zone and especially the North Anatolian fault zone (NAFZ). Local MARNET stations, which were established in 1976 and are operated by the Kandilli Observatory and Earthquake Research Institute (KOERI), record not only earthquakes that occur in the region, but also quarry blasts. There are a few quarry-blasting areas in the Gaziosmanpa?a, Çatalca, Ömerli, and Hereke regions. Analytical methods were applied to a set of 175 seismic events (2001-2004) recorded by the stations of the local seismic network (ISK, HRT, and CTT stations) operated by the KOERI National Earthquake Monitoring Center (NEMC). Out of a total of 175 records, 148 are related to quarry blasts and 27 to earthquakes. The data sets were divided into training and testing sets for each region. In all the models developed, the input vectors consist of the peak amplitude ratio (S/P ratio) and the complexity value, and the output is a determination of either earthquake or quarry blast. The success of the developed models on regional test data varies between 97.67% and 100%.     

Modeling Fully Depleted SOI MOSFETs in 3D Using Recursive Scattering Matrices

As the semiconductor industry pushes towards ever decreasing device sizes, the need for an efficient yet accurate simulation method increases. We present a different approach to modeling ultra small semiconductor devices through the use of recursive scattering matrices. This approach is a completely quantum mechanical approach in three dimensions, yet does not suffer from excessive computation time or resources. While the transport in most small semiconductor devices is typically 2D in nature, with a 3D model we are capable of incorporating the interaction of the 3D modes in the contacts with the 2D modes in the active regions. We demonstrate this approach by presenting results for a short channel fully-depleted SOI (Silicon On Insulator) MOSFET. We present results using both hardwall potentials and self-consistent potentials as calculated through the use of an iterative Poisson solver.     

Modeling of hermetic transitions for microwave packages

Two numerical techniques, the finite difference in time domain (FDTD) and the finite element method (FEM) in frequency domain, are employed to characterize microstrip hermetic transition geometries in an effort to investigate high-frequency effects. Measurements performed on these transitions compare favorably with theory. Two different types of transitions have been analyzed from 10 to 25 GHz and have been found to be limited in performance by higher return loss as frequency increases. It is shown that microstrip-through-CPW hermetic transitions in the shielded environment may suffer from parasitic waveguide modes which, however, can be eliminated with the use of vias at appropriate locations. The hermetic wall on top of the CPW section shows a relatively small (≤ 2 dB) effect on the original circuit performance. Similarly, the hermetic bead transition shows good performance at a lower frequency region while it degrades as frequency increases. This indicates the need for very careful characterization of transitions intended for use in microwave and millimeter-wave applications. © 1996 John Wiley & Sons, Inc.     

Elastoplastic analysis of functionally graded spherical pressure vessels

Purely elastic, partially plastic and fully plastic stress states of internally pressurized functionally graded spherical pressure vessels are investigated analytically in the framework of small deformation theory. The modulus of elasticity and the uniaxial yield limit of the spherical pressure vessel material are assumed to vary nonlinearly in the radial direction. The plastic model is based on Tresca’s yield criterion and ideal plastic material behavior. It is shown that, unlike in the case of a homogeneous spherical pressure vessel, different modes of plasticization may take place due to the radial variation of the functionally grading parameters.     

Influence of the harvesting year and fertilizer on the fatty acid composition and some physicochemical properties of linseed (Linum usitatissimum L.)

Sar? 85 (Linum usitatissimum L.) linseed variety was used in this study. Linseed was cultivated at 2008 (LS-08) and 2009 (LS-09) without fertilizer. In addition, at 2009 diammonium phosphate [(NH₄)₂HPO₄] and ammonium nitrate (NH₄NO₃) were applied (LSF-09). The linseeds were analyzed for protein, ash and oil contents and fatty acid compositions. There were differences among harvesting years for oil, protein and ash contents of the seeds. The greater oil and protein contents were obtained during LS-08 compared with LS-09. There were no significant difference in protein and ash content between LS-09 and LSF-09 while a significant difference was observed in oil content. Seed protein, oil and ash contents were significantly affected by the harvesting year, but only oil content was affected by the fertilizer treatment. There are significant differences in palmitic, stearic, oleic, ??-linolenic and arachidic acid between LS-08 and LS-09. While palmitic, stearic, oleic acid decreased, ??-linolenic and arachidic acid increased during 2009 harvesting year. LSF-09 has the highest amount of ??-linolenic acid. The fertilizing treatment seems to have an increasing effect on the amount of ??-linolenic acid, while it has a decreasing effect on the oleic acid content.     

The Effective Potential in Device Modeling: The Good, the Bad and the Ugly

We discuss the use of the effective potential to incorporate quantum effects in device models. While threshold shifts and charge set-back are handled well, tunneling is not well handled by this approach, or by any other local potential approach.     

Eigenstate Selection in Open Quantum Dot Systems: On the True Nature of Level Broadening

We show that transport in open quantum dots can be mediated by single eigenstates, even when the leads allow several propagating modes. The broadening of these states, generally localized in the interior, can be virtually independent of lead width. As such, the Thouless argument, invoked to suggest that all states should be unresolvable under these conditions, can in fact fail. Thus, any transport theory based on such assumptions (in particular, random matrix theory) must be called into question, as the fluctuations produced by these states can in fact dominate the conductance. These trapped states also produce interesting and potentially useful effects in coupled dot systems as well.     

The effect of an H2-receptor antagonist on small-bowel colonization and bacterial translocation in newborn rats

Bacterial translocation (BT) is defined as the passage of enteric bacteria from the gastrointestinal tract to extraintestinal tissues. Bacterial overgrowth is one of the main promoting factors of BT, which is thought to play an important role in the pathogenesis of sepsis and necrotizing enterocolitis. It is believed that small-bowel colonization is established by bacterial spread through the rectum. Gastric acid is also involved in this process. An experimental study was designed for investigating the effect of gastric acid inhibition with the use of an H2-receptor antagonist on intestinal colonization and BT in newborn rats. Animals were divided into two groups: the ranitidine group (n = 20) received ranitidine 10 mg/kg per day intramuscularly for 5 days; the control group (n = 30) received saline solution. Mesenteric lymph node, spleen, liver, stomach, small bowel/cecum, and large bowel specimens were obtained from each rat 5 days later and gram-negative and -positive aerobic bacteria identified by the use of chocolate and Endo agar. It is concluded that: (1) there was a strong correlation between gastric and small-bowel bacterial colonization in the ranitidine group; (2) no correlation between large-and small-bowel colonization could be demonstrated; and (3) BT occurred only in the ranitidine group.     

Plasma platelet-activating factor levels in newborn infants with and without perinatal asphyxia: is it an additional marker of perinatal asphyxia?

We report a case of severe hyperthermia in a 6-month-old boy with a single ventricle, dextrocardia, asplenia, and transposition of the great arteries, during induction of anesthesia on three separate occasions. To our knowledge, this is the first case reported of repeated intraoperative hyperthermia not related to malignant hyperthermia, infection, neuroendocrine tumor, or iatrogenic causes (e.g., anticholinergic blockade or warming devices). The severe hyperthermia may be secondary to the medications given before and during induction and/or the stress of the induction. Among the induction medications given during the three episodes, fentanyl is the most likely contributing drug. Human data indicate that opioids increase the sweating threshold and decrease the vasoconstriction and shivering thresholds. The medications could cause a widening in the thermoregulation interthreshold and the stress could induce nonshivering thermogenesis.