The relationship between oil prices and long-term interest rates

We estimate a seven-variable-VAR for the U.S. economy on postwar data using long-run restrictions, taking changes in long-run interest rates and inflation expectations into account. We find a strong connection between oil prices and long-run nominal interest rates which has lasted throughout the entire postwar period. We find that a simple off-the-shelf theoretical model of oil prices and monetary policy, where oil prices are flexible and other prices are sticky, in fact predicts a strong relationship if inflation and oil prices were driven by monetary policy. The observed magnitude of this relationship is still a bit of a puzzle, but this finding does call into question the identification techniques commonly used to identify oil shocks

The effect of inflation on real commodity prices

Recent research has shown that economic conditions have an important effect on real commodity prices. We quantify the contribution of fluctuations in inflation to this particular link. In the data, a temporary rise in inflation causes real commodity prices to rise, as does a rise in trend inflation. We find that a simple dynamic equilibrium model of commodity supply and demand gives a realistic response of real commodity prices to inflation. Based on historical simulations, shocks to inflation played an important role in commodity price dynamics during the 1970s, but they have contributed negligibly to commodity price movements since then

Simulation study of the interaction between large-amplitude HF radio waves and the ionosphere

The time evolution of a large-amplitude electromagnetic (EM) wave injected vertically into the overhead ionosphere is studied numerically. The EM wave has a carrier frequency of 5 MHz and is modulated as a Gaussian pulse with a width of approximately 0.1 milliseconds and a vacuum amplitude of 1.5 V/m at 50 km. This is a fair representation of a modulated radio wave transmitted from a typical high-power HF broadcast station on the ground. The pulse is propagated through the neutral atmosphere to the critical points of the ionosphere, where the L-O and R-X modes are reflected, and back to the neutral atmosphere. We observe mode conversion of the L-O mode to electrostatic waves, as well as harmonic generation at the turning points of both the R-X and L-O modes, where their amplitudes rise to several times the original ones. The study has relevance for ionospheric interaction experiments in combination with ground-based and satellite or rocket observations.Comment: 6 pages, 7 figure

Direct observation of the behavior of the heavy single atoms on amorphous carbon substrates

Using a scanning transmission electron microscope it is possible, by directly imaging single atoms, to investigate the motion and distribution of heavy (high-Z) atoms deposited on the surfaces of thin low-Z films. In this study, the heavy atoms U, Pt, Au, In, Cd, Ag, and Pd were deposited on 15-Å-thick amorphous carbon substrates. It is found that adatom motion is strongly dependent upon local substrate structure and adatom species. Diffusion coefficients and activation energies for single atoms, as well as dimers, trimers, etc., have been obtained by directly measuring the motion of the atoms. Pair-density and nearest-neighbor distributions were measured and used to derive the interatomic potential and the rate of adatom nucleation. It is found that the interatomic potential is very weak and long ranged

Computer simulations of submicron FIB system optics

The design of the optical elements for a focused ion beam (FIB) system having a 50 mm spot size over a 1 mm square field requires extensive computational analysis. We discuss the mathematical techniques applied to the components of interest in this submicron FIB system; the electrostatic lenses, the mass analyzer, and the electrostatic deflectors. The results of ion trajectory calculations predicted for the whole FIB column by the computer code snow are presented. The aberration coefficients to third order and a parametric study of a stigmatic Wien filter whose design includes entrance and exit fringe field effects will be considered. We also cover our optimization algorithms for selecting lens and deflector elements which demonstrate minimal chromatic and spherical aberrations and distortions. A spot symmetry and spot location map for the final 1 mm square field and its 50 nm image constraint is shown for mixed electronic configurations of dynamic focus, dynamic distortion, and dynamic stigmation correctors. A comparison of the computer predictions to measured values of lens parameters is given for a typical liquid metal source and its extractor lens. The equipotentials in the vicinity of a representative lens is plotted with emphasis on the dielectric‐conductor interface in order to demonstrate the significance of stressed electric fields to the hardware designer

A focused ion beam secondary ion mass spectrometry system

This article describes a Ga+ focused ion beam secondary ion mass spectroscopy system, and measures several quantities of interest to aid in interpreting secondary ion mass spectroscopy results. We have measured sputter yields and rates, estimated the instrument efficiency, and calculated useful yields and practical sensitivities for a variety of elements used in the semiconductor industry. We have performed measurements at the system base pressure, and have also introduced oxygen and iodine to determine any enhancement effects

Fundamental limits to imaging resolution for focused ion beams

This article investigates the limitations on the formation of focused ion beam images from secondary electrons. We use the notion of the information content of an image to account for the effects of resolution, contrast, and signal‐to‐noise ratio and show that there is a competition between the rate at which small features are sputtered away by the primary beam and the rate of collection of secondary electrons. We find that for small features, sputtering is the limit to imaging resolution, and that for extended small features (e.g., layered structures), rearrangement, redeposition, and differential sputtering rates may limit the resolution in some cases

Transverse thermal velocity broadening of focused beams from liquid metal ion sources

Experiments have shown that the target current density in focused ion beam columns have long ‘‘tails’’ outside the central submicron region. We show that these tails result from a transverse velocity distribution which has a Holtsmark probability density. Both theory and experiment show that the tails are reduced as the system magnification and source current are reduced

Focused Ion Beam Fabrication

Contains summary of research program and reports on four research projects.Charles Stark Draper Laboratory (Contract DL-H-225270)Hughes Research LaboratoriesInternational Business Machines, Inc. (Contract 456614)Nippon Telegraph and Telephone, Inc.U.S. Navy - Office of Naval Research (Contract N00014-84-K-0073)U.S. Department of Defense (Contract MDA903-85-C-0215)Hitachi Central Research Laborator