Excitation of untilted edge slots by a suspended slotline

The excitation mechanism of an untilted slot in the narrow wall of a rectangular waveguide by a suspended slotline has been described. Power radiated by this slot as a function of the slot width of the suspended slotline has been measured. This excitation mechanism appears promising for microwave integrated circuit antennas.<>     

Effect of butylated hydroxyanisole on catalase activity and malondialdehyde content in aging Zaprionus paravittiger (diptera)

Catalase activity and malondialdehyde (MDA) content were measured in whole body and mitochondrial homogenates of the banana fruit fly, Zaprionus paravittiger, fed on control and butylated hydroxyanisole (BHA, 10 mM) mixed diets. Catalase activity increased during the reproductive period and decreased thereafter with age. However, the MDA content increased with advancing age in both sexes. In general, females exhibited higher catalase activity and lower MDA content as compared to their male counterparts. BHA feeding increased catalase activity significantly during all age intervals in both sexes. Mitochondrial fractions had lower catalase activity and lower MDA content than whole body homogenates. However, the pattern of changes was similar in both homogenates with age as well as on antioxidant feeding. These results suggest that BHA strengthens the defense mechanism of the insects by increasing catalase activity and reducing MDA content which may be responsible for increased longevity of insects.     

Studies on the oxidation behavior of Inconel 625 between 873 and 1523 K

The oxidation behavior of Inconel 625 during the early stages (<150 min) has been studied at oxygen pressures (P_{O 2}) of 0.12 kPa (0.9 torr) and 101.3 kPa (760 torr) in the temperature range of 1323 K to 1523 K by using TGA and between 873 and 1523 K by using XPS, AES, and EDS. The TGA results correlated well with those obtained by surface analysis of the oxide films. The results of XPS and AES analysis suggested that two distinctly different oxidation mechanisms operate, depending on the temperature of oxidation. Enrichment of the oxide films with respect to Cr₂O₃ occurs above 873 K, the degree of enrichment peaking at about 1200 K such that the oxide films formed at temperatures close to this consist almost exclusively of Cr₂O₃. At temperatures above 1300 K, the oxides of two minor alloying components, Nb and Ti, have been found to be present in the oxide films in significant proportions. The results have been discussed on the basis of the relative thermodynamic stabilities of the competing oxide phases and the diffusivities of the alloying elements in Inconel 625.     

A device design methodology for sub-100-nm SOC applications using bulk and SOI MOSFETs

CMOS for the mixed-mode applications has gained much interest recently. While the International Technology Roadmap for Semiconductors provides two different scaling guidelines for the analog and digital circuit operation using the bulk MOSFET, there are no well-defined scaling guidelines for improving the analog performance of silicon-on-insulator (SOI) MOSFETs. This paper presents a systematic and quantitative comparison between the analog characteristics of the bulk and SOI technology. The intrinsic gain, f/sub T/ and g/sub m//I/sub ds/ ratio are considered as a metric for this comparison. It is shown that, even for the operating frequencies in the range of gigahertz (where the ac kink effect is suppressed), analog performance of SOI devices is inferior to that of the bulk devices due to the capacitive drain-to-body coupling. Based on our study, we show that hat the gate-workfunction engineering (close to mid-gap workfunction) is essential in fully depleted SOI (FDSOI) devices for improving analog performance. The analog performance of partially depleted SOI (PDSOI) devices can be improved by using body-tied structures. An increased gate control in double-gate MOSFETs can provide very high output resistance for short-channel devices.     

Improved EEPROM tunnel- and gate-oxide quality by integration of alow-temperature pre-tunnel-oxide RCA SC-1 clean

The effects of integration of a low-temperature RCA standard clean-1 (SC1) on the tunnel- and gate-oxide charge-to-breakdown (Q_BD) and voltage ramped dielectric breakdown (VRDB) distribution in a 0.7 μm CMOS EEPROM process technology were studied. A low-temperature (<65°C) SC1 used to clean the wafer surface prior to tunnel oxidation resulted in a significantly higher tunnel-oxide Q_BD, as well as improved gate-oxide Q_BD and mode-B failure rates compared to that for a traditional high temperature (>80°C) SC1. The reduced silicon diode etchrate of the low-temperature SC1 allowed for additional gate-oxide annealing during the gate oxidation cycle, while keeping the overall thermal budget (Dt)^1/2 for the technology equivalent to that with the higher temperature SC1. This resulted in improved gate-oxide VRDB distributions and QED values on large capacitor structures. The tunnel-oxide QBD improvement was most likely due to reduced surface roughness in the tunnel-oxide window regions with the lower temperature SC1. The process including the low-temperature SC1 was also proven to provide equivalent yield to the process with the high temperature SC1 on a 0.7 μm, 7 nS 128 macrocell EEPROM programmable logic device     

On algorithms for digital signal processing of sequences

In this work, we analyze the algebraic structure of fast algorithms for computing one- and two-dimensional convolutions of sequences defined over the fields of rational and complex rational numbers. The algorithms are based on factorization properties of polynomials and the direct sum property of modulo computation over such fields. Algorithms are described for cyclic as well as acyclic convolution. It is shown that under certain nonrestrictive conditions, all the previously defined algorithms over the fields of rational and complex rational numbers are also valid over the rings of finite integers. Examples are presented to illustrate the results.