Half Orders Of Magnitude Research Articles

Optical Second-Harmonic Generation with Surface Plasmons in Silver Films

We report the first experimental and theoretical investigation of the coupling of second-harmonic generation of light to surface plasmons in thin silver films. A model of second-harmonic generation due to polarization sources at the silver-air interface correctly predicts the observed harmonic enhancement of one and a half orders of magnitude because of excitation of the surface plasmon.

Electrical conductivity jump produced by the α-β-δ transformation in Mn 2GeO 4

The electrical conductivity of three polymorphs of Mn 2GeO 4 was measured under high pressures in the temperature range of 300–1200 K. It was found that the electrical conductivity increases discontinuously due to the transformation both from olivine structure (α) to modified spinel structure (β) and from β to strontium plumbate structure (δ). The amount of discontinuous change is about one half order of magnitude from α to β and one third order of magnitude from β to δ at 1200 K. In order to see the effect of the presence of iron ions, the electrical conductivity of the solid solution of (Mn 0.9Fe 0.1) 2GeO 4 was also measured. It was found that at low temperatures, where impurity conduction may be dominant, the solid solution is more conductive than the pure Mn 2GeO 4, but at high temperature no significant differences were observed between the solid solution and pure Mn 2GeO 4 in all polymorphs. A phase transformation from modified spinel structure to strontium plumbate structure is considered to be one of the plausible transformations occurring at a depth around 650 km in the earth's mantle. These experiments suggest that if this kind of transformation occurs in the mantle, some degrees of discontinuous change in electrical conductivity may be expected around 650 km.

Atomabsorption mit gesteuerter flüssigkeitszufuhr zum turbulenzbrenner

The solution volume aspirated per unit time by a total consumption burner depends on various parameters and cannot be preselected at will. By means of external control of the solution uptake rate, the application range of total consumption burners can be extended considerably. Using a piston pump, the behaviour of the burner was investigated at solution uptake rates from 0.1 to 6.0 ml min . The flame parameters, hydrogen and air flow rates as well as the height of the light beam above the burner tip, were varied up to values of 30 and 8 l min respectively 8.2 cm. For the evaluation of the flame properties, the atomic absorption of potassium, magnesium and chromium was measured. Three total consumption burners with different diameters of the capillaries were tested. The results showed that these burners can be properly operated, even when sample flow rates were externally adjusted to higher or lower amounts as compared to free aspiration conditions. The accessible concentration range is thus extended by about one and a half order of magnitude. Best results are achieved with burners with narrow capillaries. The optimum values of the other flame parameters (gas flow rates, height of light beam) vary little with the solution uptake rate. The shape of the calibration curves and the efficiency of the apparatus are discussed in terms of the solution uptake rate. Operation of total consumption burners with externally controlled solution flow rates offers a number of advantages which can be used for routine work. With the aid of a peristaltic pump and an automatic sampler, the apparatus can be extended reliably for series analyses. The pulsation of the peristaltic pump was smoothed by a damping device. This system has proved its usefulness since more than three years.

Ground effects from the Boxcar and Benham nuclear explosions

abstract Formulas were developed by the authors in 1957 for the purpose of estimating maximum ground accelerations and transitory displacements resulting from the 1.7 kt Rainier shot and subsequent underground nuclear detonations. These formulas when extrapolated more than 4 orders of magnitude upward came within a half order of magnitude of predicting ground motion data resulting from the Boxcar and Benham underground detonations. Velocity response spectra from these shots made in the distance range of 20 km, more or less, closely resembled the velocity response spectra from a magnitude 6.6 earthquake in the same distance range.