UScholar Works
 
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CreatorTitleDescriptionSubjectDate
1 Mathews, V. JohnAdaptive realization of a maximum likelihood time delay estimatorABSTRACT This paper presents an adaptive maximum likelihood method for estimating the time difference of arrival of a source signal at two spatially separate sensors. It is well-known that the maximum likelihood technique achieves the Cramer-Rao lower bound for time delay estimation error for ce...1996
2 Mathews, V. JohnAdaptive volterra filters using orthogonal structuresAbstract-This paper presents an adaptive Volterra filter that empolys a recently developed orthogonalization procedure of Gaussian signals for Volterra system identification. The algorithm is capable of handling arbitrary orders of nonlinearity P as well as arbitrary lengths of memory N for the syst...1996
3 Furse, Cynthia M.; Gandhi, Om P.Calculation of electric fields and currents induced in a millimeter-resolution human model at 60 Hz using the FDTD method with a novel time-to-frequency-domain conversionThe finite-difference time-domain (FDTD) method has previously been used to calculate induced currents in anatomically based models of the human body at frequencies ranging from 20 to 915 MHz and resolutions down to 1.31 cm . Calculations at lower frequencies and higher resolutions have been preclu...Finite-difference time-domain method; FDTD; Induced currents; Human body model1996
4 Stringfellow, Gerald B.Correlation between surface structure and ordering in GaInPGa and In atoms in Ga0.52In0.48P layers spontaneously segregate to form alternating In- and Ga-rich {111} monolayers during organometallic vapor phase epitaxial (OMVPE) growth on (001) oriented GaAs substrates, thus forming the CuPt ordered structure. This ordering phenomenon is believed to be drive...Transformations; Absorbtion spectra; Surface Properties1996
5 Furse, Cynthia M.; Lazzi, Gianluca; Gandhi, Om P.Electrical energy absorption in the human head from a cellular telephoneThe antenna of a cellular telephone in close proximity to the human head for a variety of time periods raises questions. This research uses finite-difference time-domain (FDTD) method to calculate the power deposition from a cellular telephone on a high-resolution model of a human head as measured b...Finite-difference time-domain method; FDTD; Power deposition; Human head model; Electrical energy absorption; Specific absorption rate1996
6 Furse, Cynthia M.; Gandhi, Om P.; Lazzi, GianlucaFDTD computation of power deposition in the head for cellular telephonesThe finite-difference time-domain method is used to calculate radiation pattern and specific absorption rate (SAR) in the human head due to cellular telephones. For realistic simulation of the ordinary positions of holding the phone, the ear of the model is pressed against the head, the head is tilt...Finite-difference time-domain method; FDTD; Specific absorption rate; Radiation patterns; Human head model; Power deposition1996
7 Mathews, V. JohnParallel-cascade realizations and approximations of truncated volterra systemsAbstract This paper introduces parallel-cascade realizations of truncated Volterra systems with arbitrary, but finite order of nonlinearity. Parallel-cascade realizations implement higher-order Volterra systems using parallel and multiplicative combinations of lower-order Volterra systems. Such rea...1996
8 Stringfellow, Gerald B.Solid phase immiscibility in GaInNThe large difference in interatomic spacing between GaN and InN is found to give rise to a solid phase miscibility gap. The temperature dependence of the binodal and spinodal lines in the Ga1xInxN system was calculated using a modified valence-force-field model where the lattice is allowed to relax ...Interatomic spacing; Valence-force field; epitaxial growth1996
9 Furse, Cynthia M.; Gandhi, Om P.State of the science regarding RF dosimetry, measurement and certificationCellular telephones and wireless personal communication systems (PCS) are being introduced into society at a very rapid rate. Whereas the present-day cellular telephones in the United States operate at midband transmission frequencies of about 835 MHz (about 900 MHz in Europe), higher frequencies o...RF dosimetry; Cell phone safety1996
10 Stringfellow, Gerald B.Surface photoabsorption study of the effect of V/III ratio on ordering in GaInPCu-Pt ordering is widely observed in Ga0.5In0.5P layers grown by organometallic vapor phase epitaxy. The degree of order is a strong function of the input partial pressure of the phosphorus precursor, i.e., the V/III ratio, during growth. By observing the surface structure using in situ surface p...Degree of order; Photoluminescence; Transmission electron microscopy1996
11 Hendee, Shonn P.; Faour, Fouad A.; Christensen, Douglas A.; Patrick, Baharah; Durney, Carl H.; Blumenthal, Donald K.Effects of weak extremely low frequency magnetic fields on calcium/calmodulin interactions.Mechanisms by which weak electromagnetic fields may affect biological systems are of current interest because of their potential health effects. Lednev has proposed an ion parametric resonance hypothesis (Lednev, 1991, Bioelectromagnetics, 12:71-75), which predicts that when the ac, frequency of a c...Electromagnetic Fields; Calcium-binding Proteins; Lednev's Theory1996-06
12 Furse, Cynthia M.; Gandhi, Om P.Memory efficient method of calculating specific absorption rate in CW FDTD simulationsSpecific absorption rate (SAR) distributions in man models are often calculated using the finite-difference time-domain (FDTD) method. The traditional method of calculating SAR requires calculation and storage of the three electric field components in each cell and is therefore very time- and memor...Specific absorption rates; SAR; FDTD simulations; Finite-difference time-domain; Mass-normalized time-averaged energy distribution1996-05
13 Stringfellow, Gerald B.Effects of V/III ratio on ordering in GaInP: atomic scale mechanismsGa0.5In0.5P layers have been grown by organometallic vapor-phase epitaxy using various values of input V/III ratio for two phosphorus precursors, phosphine, the conventional precursor, and tertiarybutylphosphine (TBP), a newly developed, less-hazardous precursor. For growth on nominally (001) GaAs s...Photoabsorption spectroscopy; Transmission electron diffraction; Phosphorus precursor1996-05-01
14 Furse, Cynthia M.; Gandhi, Om P.; Lazzi, GianlucaElectromagnetic absorption in the human head and neck for mobile telephones at 835 and 1900 MHzWe have used the finite-difference time-domain method and a new millimeter-resolution anatomically based model of the human to study electromagnetic energy coupled to the head due to mobile telephones at 835 and 1900 MHz. Assuming reduced dimensions characteristic of today's mobile telephones, we h...Electromagnetic absorption; FDTD; Finite-difference time-domain; Specific absorption rates; SAR1996-01-01
15 Mathews, V. JohnParallel-cascade realizations and approximations of truncated volterra systemsThis paper introduces parallel-cascade realizations of truncated Volterra systems with arbitrary, but finite order of nonlinearity. Parallel-cascade realizations implement higher-order Volterra systems using parallel and multiplicative combinations of lower-order Volterra systems. Such realizations ...1996-01-01
16 Stringfellow, Gerald B.; Williams, Clayton C.Spatial mapping of ordered and disordered domains of GaInP by near-field scanning optical microscopy and scanning capacitance microscopyImaging of topography, locally induced photoluminescence and Fermi-level pinning in adjacent ordered and disordered domains on a cleaved GaInP sample is performed using a near-field scanning optical microscope and scanning capacitance microscope at room temperature in air. Highly localized photolumi...Gallium Phosphides; Surface Structure; Photoluminescence1996-04-13
17 Stringfellow, Gerald B.Surface photoabsorption study of the effect of substrate misorientation on ordering in GaInPSubstrate orientation strongly affects Cu-Pt ordering in Ga0.5In0.5P layers grown by organometallic vapor phase epitaxy. In situ surface photoabsorption SPA measurements were used to measure the concentration of 1 10-oriented P dimers, characteristic of the 2 4 reconstructed surface, as a functio...P-dimer concentration; Photoluminescence measurements; Surface reconstruction1996-04-15
18 Stringfellow, Gerald B.Surface photoabsorption study of the effects of growth temperature and V/III ratio on ordering in GaInPSurface photoabsorption (SPA) measurements were used to clarify the Cu-Pt ordering mechanism in Ga0.5In0.5P layers grown by organometallic vapor phase epitaxy. The Cu-Pt ordering is strongly affected by the growth temperature and the input partial pressure of the phosphorus precursor, i.e., the V/II...P-dimer concentration; Oriented phosphorus dimers; Surface reconstruction1996-05-01
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