A radix-8 wafer scale FFT processor

Wafer Scale Integration promises radical improvements in the performance of digital signal processing systems. This paper describes the design of a radix-8 systolic (pipeline) fast Fourier transform processor for implementation with wafer scale integration. By the use of the radix-8 FFT butterfly wafer that is currently under development, continuous data rates of 160 MSPS are anticipated for FFTs of up to 4096 points with 16-bit fixed point data.     

Two-electrode DFB laser filter used as a wide tunable narrow-bandFM receiver: tuning analysis, characteristics and experimental FSK-WDMsystem

Characteristics of a two-electrode DFB laser filter are studied both theoretically and experimentally. Using a matrix analysis of spontaneous emission, a continuous tuning range of 6.7 Å is achieved by changing both net field gains of the two electrodes. A total discontinuous tuning range of over 10 nm comprising alternating mode jumps and continuous tuning range of 4 Å are measured experimentally. The laser filter presents a FWHM bandwidth of 5 GHz which depends on the optical input power. In addition, it is demonstrated that a DFB laser filter can act as a frequency discriminator/photodetector, i.e., a narrow-band FM receiver, with a uniform bandwidth of 1.5 GHz. Using the two-electrode DFB laser for both transmitter and receiver, a two-channel FSK-WDM transmission system utilizing the discontinuous tuning range is reported. The advantage of such a device is the simplicity as compared to the heterodyne technique     

Multiple drafts and legal liability: a hazard for professionalwriters

The overall legal significance of multiple drafts of professional communications is discussed. In particular, some of the legal principles that govern the status of written documents, such as the applicable rules of court are reviewed, and the types of litigation in which previous drafts can figure prominently are examined. The possibility of multiple draft liability in light of the current emphasis on writing as a process, with writers encouraged to turn off the editorial sides of their brains during the early stages of composing, is considered     

Comprehension of arithmetic word problems: A comparison of successful and unsuccessful problem solvers.

It is proposed that when solving an arithmetic word problem, unsuccessful problem solvers base their solution plan on numbers and keywords that they select from the problem (the direct translation strategy), whereas successful problem solvers construct a model of the situation described in the problem and base their solution plan on this model (the problem-model strategy). Evidence for this hypothesis was obtained in 2 experiments. In Experiment 1, the eye fixations of successful and unsuccessful problem solvers on words and numbers in the problem statement were compared. In Experiment 2, the degree to which successful and unsuccessful problem solvers remember the meaning and exact wording of word problems was examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Large-scale quantum mechanical simulations of high- Z metals

High-Z metals constitute a particular challenge for large-scale ab initio electronic-structure calculations, as they require high resolution due to the presence of strongly localized states and require many eigenstates to be computed due to the large number of electrons and need to accurately resolve the Fermi surface. Here, we report recent findings on high-Z metals, using an efficient massively parallel planewave implementation on some of the largest computational architectures currently available. We discuss the particular architectures employed and methodological advances required to harness them effectively. We present a pair-correlation function for U, calculated using quantum molecular dynamics, and discuss relaxations of Pu atoms in the vicinity of defects in aged and alloyed Pu. We find that the self-irradiation associated with aging has a negligible effect on the compressibility of Pu relative to other factors such as alloying. The US Goverment’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Synthesis,Structure, and Physicochemical Properties of AI 4[UO2(CO3)3]·nH2O (AI = Li,Na, K,NH4)

Procedures for the synthesis of Li₄[UO₂(CO₃)₃]·1.5H₂O, Na₄[UO₂(CO₃)₃], K₄[UO₂(CO₃)₃], (NH₄)₄[UO₂(CO₃)₃], and K₃Na[UO₂(CO₃)₃] were optimized. The structures of these compounds and their thermolysis were studied by X-ray diffraction, precision IR spectroscopy, and thermal analysis. The standard enthalpies of formation of these compounds at 298.15 K were determined by reaction calorimetry.     

Effect of low temperature and environment on the kinetics of fatigue crack growth in VT5-1kt titanium alloy with different microstructures

Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 27, No. 6, pp. 69–71, November–December, 1991.