The structure of Ge(105)-(1 x 2) grown on Si(105) is examined by scanning tunneling microscopy (STM) and first-principles calculations. The morphology evolution with an increasing amount of Ge deposited documents the existence of a tensile surface strain in Si(105) and its relaxation with increasing coverage of Ge. A detailed analysis of high-resolution STM images and first-principles calculations produce a new stable model for the Ge(105)-(1 x 2) structure formed on the Si(105) surface that includes the existence of surface strain. It corrects the model developed from early observations of the facets of "hut" clusters grown on Si(001).

Pi 2 magnetic pulsations are frequently observed at synchronous orbit by the UCLA fluxgate magnetometer on ATS 6. Events that occurred in September 1974 have been studied by using digital power spectra and coherency analysis to determine wave characteristics. From examination of wave form and application of spectral analysis, these Pi 2 events can be divided into three types. The first is a superposition of a 100‐s oscillation and a large‐amplitude, higher‐frequency Pi 1 activity. The second is a 100‐s wave unaccompanied by Pi 1. Both types have a significant compressional component. The third is a pure transverse wave in the azimuthal component. The pure transverse waves are quite rare, while the compressional waves occur during almost every substorm. In general, if the satellite is in the local time sector 1900–0300 LT, a Pi 2 burst accompanies every onset. In addition, onsets at the satellite are associated with ground Pi 2 bursts. The peak occurrence time of the satellite Pi 2 is 2100 LT. An examination of Pi 2 polarization at the satellite suggests that a polarization reversal occurs around midnight during quiet magnetic conditions (Kp ≤ 3+), left‐handed premidnight and right‐handed postmidnight. This result is similar to that obtained from ground‐based studies at stations equatorward of the auroral electrojet. The initial perturbation in the azimuthal component of a Pi 2 event is in the same sense as the perturbations caused by substorm‐associated, field‐aligned currents, positive (eastward) premidnight, negative (westward) postmidnight. This observation indicates that there may be a very close association between their causative mechanisms.

Electron-field-emission properties have been investigated systematically for carbon nanotubes (CNTs) fabricated on a metal tip. With a vacuum gap of 0.7 mm, the threshold field is as low as 0.7 V/μm and the current density approaches 10 mA/cm2 at an electronic field of 1.0 V/μm. The emission current is quite stable with very low fluctuation. The emission behavior is in excellent agreement with Fowler–Nordheim theory and no current saturation is found even with an emission current reaching 1 A/cm2. A universal relationship 1/β=d2/d+1/β0 between the field amplification factor β and the vacuum gap d is developed within a two-region field-emission model. This relationship provides the basis for a microscopic understanding of CNT emitters and is applicable to other systems as well.

Raman spectra of ZrOz were measured in the range 300" to 1600°K. Irreducible components of the Raman spectra were obtained from polarization measurements at room temperature, and the symmetries of the Raman-active modes in the monoclinic phase were determined. The temperature dependence of the spectra shows a hysteresis. In the temperature range of phase change, two kinds of Raman lines coexist. Six Raman-active mode frequencies were found in the tetragonal phase at high temperatures. Analysis of the spectra showed that the Raman-active modes in the tetragonal phase are affected by strain introduced into the crystals during the phase transformation.

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