This paper derives new analytical results for quantifying the performance degradation induced by finite precision arithmetic upon the autocorrelation method and Burg's algorithm for linear ...prediction. The main results are analytical derivations of the resulting error in the reflection coefficient computation due to finite precision (FP) arithmetic implementation. From analysis of the second-order system, it is shown that for the autocorrelation method, FP effects are more dominant for signals having spectral poles which are near the unit circle and the real axis in the z plane. In this circumstance, analytical results show that the autocorrelation method indeed has severe degradation due to FP implementation. However, analytical results show that Burg's algorithm has FP properties superior to the autocorrelation method. Finally, experimental results are presented which show very close agreement between the analytical derivations and experimental results.
We have carried out a multiwavelength observational campaign demonstrating some of the remarkable properties of the infrared-bright variable star BP Psc. Surrounded by a compact dusty, gaseous disk, ...this little-studied late-G (or early-K) type star emits about 75% of its detected energy flux at infrared wavelengths. Evidence for accretion of gas in conjunction with narrow bi-polar jets and Herbig-Haro objects is apparently consistent with classification of BP Psc as a pre-main sequence star, as postulated in most previous studies. If young, then BP Psc would be one of the nearest and oldest known classical T Tauri stars. However, such an evolutionary classification encounters various problems that are absent or much less severe if BP Psc is instead a luminosity class III post-main sequence star. In this case, it would be the first known example of a first ascent giant surrounded by a massive molecular disk with accompanying rapid gas accretion and prominent jets and HH objects. In this model, the genesis of the massive dusty gaseous disk could be a consequence of the envelopment of a low mass companion star. Properties in the disk may be conducive to the current formation of planets, a gigayear or more after the formation of BP Psc itself.
When integrating more than one chip in a package using so-called SiP (system-in-package) technology, the size reduction rate is approximately 30/spl sim/60% compared to the identical PCB (printed ...circuit board). In this paper, we review the advantages of using SiP first, and then some of the reliability issues are discussed, including leakage current, test, EMI (electromagnetic interference), EOS (electrical over stress) and latch-up, related to using SiP. Solutions to these reliabilities are proposed in this paper.
The aim of this research is to produce 2-2 PZT/polymer composite using tape casting technology. PZT tapes were printed with a fugitive phase (carbon) to define voids which were then backfilled with ...epoxy after the carbon was removed by thermal treatment at 1250/spl deg/C. Final dimensions of the 2-2 composite were in the range of 25 /spl mu/m for the ceramic bar and 5 /spl mu/m for the epoxy-filled kerf. Specific emphasis was placed on achieving uniformity and straightness of the ceramic beam and kerf thicknesses. The composites were fabricated into 20 MHz single element pachymeters and benchmarked against commercial devices fabricated by dice-and-fill. The tape cast material compared favorably with high sensitivity and a little lower bandwidth. Fabrication of a 35 MHz linear array transducer is in progress. Electrode patterning to define individual array elements has been successfully completed.
For the preparation of solid polymer electrolytes with high conductivity and good mechanical properties, organically modified ceramic electrolytes were prepared based on low molecular weight ...poly(ethylene glycol), lithium salt and an inorganic matrix produced by sol-gel process of tetraethoxysilane and a new poly(ethylene glycol)-modified sol-gel precursor which was synthesized by the reaction of mono-methoxy terminated poly(ethylene glycol) and 3-isocyanatopropyl triethoxysilane. Transparent and self-supporting films were obtained showing high ionic conductivities (3.2 × 10
−6
∼ 1.4 × 10
−4
S/cm) at room temperature.
A bacterial strain which is able to degrade pyridine was previously isolated from the oxic ozone of an oil shale column and described as Pimelobacter sp. strain OS4 super(T). However, Pimelobacter ...species have been transferred to the genera Nocardioides and Terrabacter. Strain OS4 super(T) was identified as a member of the genus Nocardioides on the basis of chemotaxonomic analysis and phylogenetic inference based on 16S ribosomal DNA (rDNA) sequence analysis. The G+C content of strain OS4 super(T) is 72.5 mol%. The cell wall peptidoglycan contains LL-diaminopimelic acid as the diamino acid. The predominant menaquinone is MK-8(H sub(4)). The cellular fatty acid profile of strain OS4 super(T) is similar to that of the genus Nocardioides. The 16S rDNA similarity of strain OS4 super(T) with previously described Nocardioides species is 94.5% plus or minus 0.7%, and a phylogenetic tree based on 16S rDNA sequences revealed a distinct lineage for strain OS4 super(T) within the evolutionary radiation enclosed by the genus Nocardioides. Therefore, on the basis of our data, we propose that strain OS4 super(T) should be placed in the genus Nocardioides as a member of a new species, Nocardioides pyridiminolyticus. The type strain of the new species is strain OS4 (=KCTC 0074BP).
The microchannel electron source is currently being developed at the Naval Surface Warfare Center for cold cathode applications which require high repetition rates and short pulse widths. It is based ...on microchannel plate principles which, in general, allow for fast response times. However, the microchannel plate is generally limited to output currents of less than 10 -4 A/cm 2 . We describe a method to increase the output current from a microchannel device by several orders of magnitude. Our analysis has shown that one can obtain channel current densities of order 1 A/cm 2 by constructing the device from a crystalline bulk semiconductor. Carrying the analysis further suggests that current densities can be increased by another order of magnitude by incorporating an appropriate electron injection scheme. Important analytical results, as well as the present status for the fabrication of a proof-of-principle device, are discussed.
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