Mutual impedance effects in scanned antenna arrays technical report no. 2

Mutual impedance effects in electronically-scanned antenna array

The measurement of harmonics produced by a pin diode in a microwave switching application Final report

Measurement of harmonics produced by a pin diode in microwave switc

Electronic scanning and beam shaping methods technical report no. 1

Electronically scanned antenna array and beam scannin

The Vector Analyzing Power in Elastic Electron-Nucleus Scattering

The vector analyzing power A_n is calculated for elastic electron scattering from a variety of spin zero nuclei at energies from 14 MeV to 3 GeV. Time reversal symmetry insures that A_n vanish in first Born approximation. Therefore A_n depends on Coulomb distortions and can be large for scattering from heavy nuclei. The vector analyzing power is a potential source of systematic error for parity violation experiments. We find that A_n=-0.361 ppm for the kinematics of the Parity Radius Experiment (PREX) involving 850 MeV electrons scattering at six degrees from 208Pb. This is comparable to the parity violating asymmetry. However for HAPPEX He involving 3 GeV electrons scattering on 4He we find that A_n is very small.Comment: 6 pages, 6 figures, submitted to Phys. Rev.

Towards first-principles understanding of the metal-insulator transition in fluid alkali metals

By treating the electron-ion interaction as perturbation in the first-principles Hamiltonian, we have calculated the density response functions of a fluid alkali metal to find an interesting charge instability due to anomalous electronic density fluctuations occurring at some finite wave vector {\bi Q} in a dilute fluid phase above the liquid-gas critical point. Since |{\bi Q}| is smaller than the diameter of the Fermi surface, this instability necessarily impedes the electric conduction, implying its close relevance to the metal-insulator transition in fluid alkali metals.Comment: 11 pages, 5 figure

An Actuarial Study of Scores Received by High School Seniors on the Cooperative School and College Ability Test and These Students\u27 Grades Received During the First Year of Attendance in South Dakota Colleges

In 1956 and 1957 college counselors felt a need for information concerning what South Dakota students were doing after they finished high school. Many questions were asked. Do out-of-state colleges lure away the outstanding students with scholarships? Do large numbers of the better students stay out of college? Do many students with great potential fail to do well in their high school studies? Are girls better achievers than boys? The South Dakota Guidance Association formed a committee to investigate some of these questions through a follow-up study. College and high school staffs have sought methods by which they could predict success in college. The problem selected by this writer was that of determining the value of the Cooperative School and College Ability Test in predicting success in college. This test is a test of “Developed Ability.” Predicted success in college will be determined by the expected grade point average derived from the test scores

Study of inexact modeling techniques Final report

Scale modeling antenna systems for aircraft and missiles with anechoic chamber evaluation and us

Diffusion in sparse networks: linear to semi-linear crossover

We consider random networks whose dynamics is described by a rate equation, with transition rates $w_{nm}$ that form a symmetric matrix. The long time evolution of the system is characterized by a diffusion coefficient $D$. In one dimension it is well known that $D$ can display an abrupt percolation-like transition from diffusion ($D>0$) to sub-diffusion (D=0). A question arises whether such a transition happens in higher dimensions. Numerically $D$ can be evaluated using a resistor network calculation, or optionally it can be deduced from the spectral properties of the system. Contrary to a recent expectation that is based on a renormalization-group analysis, we deduce that $D$ is finite; suggest an "effective-range-hopping" procedure to evaluate it; and contrast the results with the linear estimate. The same approach is useful for the analysis of networks that are described by quasi-one-dimensional sparse banded matrices.Comment: 13 pages, 4 figures, proofed as publishe

Magnetoresistance scaling in the layered cobaltate Ca3Co4O9

We investigate the low temperature magnetic field dependences of both the resistivity and the magnetization in the misfit cobaltate Ca3Co4O9 from 60 K down to 2 K. The measured negative magnetoresistance reveals a scaling behavior with the magnetization which demonstrates a spin dependent diffusion mechanism. This scaling is also found to be consistent with a shadowed metalliclike conduction over the whole temperature range. By explaining the observed transport crossover, this result shed a new light on the nature of the elementary excitations relevant to the transport