ALBERT

Notes: Abstract Synthetic one-dimensional scans of brightness fluctuations are generated from intergranulegranule profiles (IGP), which approximate observed scans of granulation fluctuations except that the local (i.e. IGP) mean intensity is kept constant. Comparing the power spectrum of such scans with the power spectrum of observed scans shows that nearly two thirds of the low-wavenumber (k 〈 0.0025 km-1) granulation power is due to this variable mean effect. This result favors the interpretation of granulation as turbulent thermal convection but cannot rule out the laminar convection interpretation.

Notes: Zusammenfassung Es wird gezeigt, daß der Einfluß des Elektron-Spins auf die Widerstandsänderung eines Metalls in einem Magnetfeld wesentlich kleiner ist als der von der Lorentzschen Kraft herrührende Effekt, im Gegensatz zu einer von F. Bloch gegebenen Abschätzung. Bis jetzt hat man keine befriedigende Erklärung weder für die neuen Kapitzaschen Messungen bei großen Feldern, noch für den normalen Effekt bei kleinen Feldern.

Notes: Zusammenfassung Es werden die vier transversalen galvanomagnetischen und thermomagnetischen Effekte bei adiabatischer Anordnung nach der Sommerfeldschen Theorie berechnet und die Beziehungen unter diesen Effekten theoretisch untersucht. Die verschiedenen thermoelektrischen Effekte in homogenen Kreisen werden diskutiert.

Notes: Summary Nanosize poly(methyl methacrylate) (PMMA) microlatexes with high PMMA/surfactant ratio have been successfully prepared by a modified microemulsion polymerization, i.e., continuous and slow addition of monomer (MMA) to the polymerizing MMA microemulsion with mild stirring. Number-average diameters of 33–46 nm with narrow polydispersity (Dv/Dn= 1.1) and polymer content of 6–24 wt% were achieved using low levels of surfactant (dodecyltrimethylammonium bromide, DTAB) — less than 1 wt% of the reaction mixture. Particle diameter depended on polymerization temperature, MMA content, and concentrations of initiator and surfactant. Larger particles wereformed when temperature was too high, initiator concentration was too high, or surfactant concentration was too low.

Notes: Abstract The application of the fast-Fourier-transform (FFT) algorithm to calculating one-dimensional and bi-dimensional (temporal and spatial), power and cross-power (coherence and phase) spectra is examined for solar photospheric fluctuations. Alternative methods for smoothing raw spectra, direct averaging (employing various weights) and indirect truncation of the correlation function, are compared, and indirect smoothing is compared with spectra calculated by mean-lagged-product (MLP) methods. Besides providing the raw spectrum, FFT techniques easily allow computing a series of spectra with varying amounts of smoothing. From these spectra a range of satisfactory compromise between resolution and stability can be determined which helps in the interpretation of spectral trends, and in identifying more clearly the existence and significance of spectral features. For bi-dimensional spectra presented as contour plots, this range of satisfactory smoothing can be restricted, particularly when spectral trends must be represented by small-scale contours. Equivalent spectra (i.e. comparable equivalent degrees of freedom) computed or smoothed by different methods have minor, but not negligible, differences. Examination of these differences favors computing of FFT spectra smoothed by averaging for photospheric fluctuations.

Notes: Abstract Fluctuations measured from a time sequence of high-resolution, high-dispersion Sacramento Peak Observatory spectrograms and previously analyzed by computing one-dimensional temporal and spatial spectra (Edmonds et al., 1965), are re-analyzed using bi-dimensional (temporal and spatial) power, coherence and phase spectra computed by fast-Fourier-transform techniques. The fluctuations measured are radial velocity for the FeI 5049.83, CrI 5051.91 and CI 5052.16 spectral lines, continuum brightness, and equivalent width and central intensity of the CI line. The bidimensional spectra, particularly those of coherence and phase, allow isolating different components of the fluctuations to a degree not possible in the one-dimensional analyses. Six components of the fluctuations have been isolated (Section 5 and Figure 11); the first three components are well-known but the nature of the remaining three is less certain: (1) Supergranulation which exists only in radial-velocity fluctuations and increases in power with depth. (2) Five-minute oscillations that dominate long-wavelength radial-velocity fluctuations, which may contribute of the order of one percent to continuum brightness and equivalent width fluctuations, and are waves which can propagate across the Sun's surface and possibly travel upwards at less than 70 km s−1. (3) A long-period, convective component which extends over all but very long wavelengths, is characterized by strong correlation between the radial velocity and photometric fluctuations, and involves low power levels for the radial velocity fluctuations. Seemingly, the radial velocity fluctuations lead those of continuum brightness by roughly 20 s. (4) Low and moderate wavenumber fluctuations which seemingly extend over frequencies ≲ 6 × 10−3 Hz and are characterized by low power levels for all types of fluctuations. It is difficult to deny the physical reality and distinctness from other components of these fluctuations, but whether they constitute a single component is uncertain. The radial velocity fluctuations seem to have the same phase relations with respect to each other as the five-minute oscillations. The continuum brightness fluctuations seem to lag the equivalent width fluctuations by roughly 17 s, lead the central intensity fluctuations by roughly 10 s, and lead the radial velocity fluctuations by roughly 15 to 20 s. (5) Possible line-formation (as distinct from continuum formation) brightness fluctuations at the center of the CI 5052.16 line, which seemingly are of low frequency and long wavelength and are poorly correlated with continuum brightness and radial velocity fluctuations. (6) A low-correlation, primarily photometric component restricted to long-periods and to wavelengths only slightly less than those of super-granulation. Its existence is suggested by a phase anomaly indicating that the radial velocity fluctuations lead the photometric fluctuations by roughly 4 min.

Notes: Abstract The fractional convective flux πF c (x c /πF) is computed for the effective level x c = logτ c = 0.125, using bi-dimensional co-spectra for relative continuum-brightness fluctuations ΔI and radial velocity fluctuations ΔV measured for the C i 5052.16 spectral line. A more uncertain flux for x Fe ≈ - 0.9 is obtained for the Fe i 5049.83 line. Since the results (Figure 1) incorporate current uncertainties in RMS ΔI , RMS ΔV and RMS ΔT (x), where ΔT are photospheric temperature fluctuations, they must be considered qualitative until these uncertainties are appreciably reduced. The requirement that the fractional convective flux 〈 1, places restrictions on these uncertainties which suggest that current RMS ΔT (x)'s are too large. The results confirm the importance of overshoot at the top of the solar hydrogen convection zone and suggest a non-negligible fractional convective flux throughout the lower photosphere. Qualitatively, they do not agree with the predictions of the generally-used, local, mixing-length theory or those of Parsons' (1969) modified mixing-length theory. However, qualitative agreement with the predictions of the non-local, generalized mixing-length theory of Spiegel (1963) and with the non-local theory of Ulrich (1970) cannot be considered as observational confirmation of these theories.

Notes: Abstract Successful subtraction of instrumental background variations has permitted spectral analyses of two-dimensional measurement arrays of granulation brightness fluctuations at the center of the disk, arrays obtained from Stratoscope I, 1959B-flight, high-resolution frames B1551 and B3241. (a) RMS's, uncorrected for instrumental blurring, are 0.0850 of mean intensity for B1551 and 0.0736 for B3241, somewhat higher than other determinations. These between-frame and between-investigation differences probably result from a combination of calibration errors, frame resolution differences, and, most likely, granulation pattern differences. (b) Significant variations over each array of mean intensities and RMS's, determined for sub-arrays with dimensions in the 2500–10000 km range, indicate spatial brightness and RMS variations larger than the ‘scale’ of the granulation pattern, supporting a turbulent interpretation of photospheric convection. (c) One-dimensional power-spectra shapes provide objective and discriminating criteria for determining granulation pattern differences and, possibly, frame resolution. (d) Two-dimensional power spectra show small, essentially random deviations from axial symmetry which lie almost entirely within the 50% confidence limits. (e) Spectral densities and fluctuation power spectra, computed from the two-dimensional power spectra and corrected for instrumental blurring, noise, and blemishes, have a useable radial wavenumber range nearly double that of earlier Stratoscope I analyses. (f) Corrected RMS's obtained from the corrected fluctuation power spectra, 0.145 ± 0.046 for B1551 and 0.136 ± 0.048 for B3241, depend critically on the accuracy of the correction. (g) The spectra's wavenumber range includes the granulation-fluctuation-producing domain but not the Kolmogoroff domain of turbulence spectra.

Notes: Abstract Three radial-velocity fluctuation arrays V(Δλ, Y) and line-formation fluctuation arrays L(Δλ, Y),where Δλ is wavelength displacement from the center of Nai D1 and Y is displacement on the Sun's surface along the spectrograph slit, were obtained from Sacramento Peak Observatory spectrograms. The variations of these line profile fluctuations are qualitatively described. The RMSυ's, coherences, and power spectra shapes for V(Δλ, Y) fluctuations are examined at different Δλ with the corresponding effective heights of formation calculated with Mein weighting functions. Results include: (a) possible anticorrelation between continuum fluctuations and those near line center; (b) RMS υ (cr) 's, which are root-mean-square values of the radial velocity corrected for instrumental and atmospheric blurring, are large (1.5 to 4.0 km s−1) primarily due to large corrections for atmospheric blurring; (c) RMS υ (cr) minima at effective heights of formation above 350 km suggest penetration of granulation velocities into the upper photosphere; (d) very rough determinations of RMS υ (cr) 's, which are additionally corrected for line-of-sight averaging, range from around 5 km s−1 in the low chromosphere to a sharp minimum ≤ 0.5 km s−1 located in the upper photosphere; (e) power spectra shapes reflect decreasing average fluctuation scales above the temperature minimum (possibly high-frequency oscillations) and in the low and middle photosphere (possibly penetration of granulation); and (f) RMS υ (cr) 's and average fluctuation scales suggest changes in the resolvable velocity field occurring near the temperature minimum.