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121.
Hong Sha Ralf Diedrichs Klaus Schwerdtfeger 《Metallurgical and Materials Transactions B》1996,27(2):305-314
The dynamic behavior of the meniscus between two liquids has been investigated experimentally using mercury and silicon oil
and theoretically by solution of the equations of motion applying the marker and cell (MAC) method. The liquids were contained
in a plexiglass tube which could be moved relative to the liquids with constant and superposed sinusoidal velocities. Special
attention was focused on the movement of the three-phase contact line (TPL) at the wall. Depending on the parameters of the
motion, the TPL may be drawn above the flat part of the oil/mercury meniscus so that the normally convex contour of the meniscus
disappears and a concave contour is formed. Good agreement was found between the measured and computed shapes of the meniscus. 相似文献
122.
In an attempt to investigate whether auditory lateralization has a heritable component, 20 monozygotic (MZ) twin pairs were examined with four different dichotic listening tests known to produce reliable right-ear advantages (REAs) in right-handers. Ten twin pairs were concordantly right-handed (MZ-RR), and ten twin pairs were discordant for handedness (MZ-RL). Intraclass correlations for MZ twin pairs were weak or nonexistent for ear advantage, but relatively strong for overall correct scores and mean reaction times, measures unrelated to laterality scores. These results support the hypothesis that auditory lateralization, as measured with dichotic tests, is nongenetic in origin. A comparison of MZ twins and right-handed siblings (n = 20) showed that right-handed siblings exhibited strong REAs, whereas left-handed siblings (n = 20) and MZ twins showed weak or absent REAs, indicating that twins may be atypically lateralized with respect to auditory lateralization. 相似文献
123.
Electrochemical and material-physical investigations of laser melted iron materials The surfaces of pure iron, St 38 and KT 45 samples were melted by a CO2-cw laser. Electrochemical and material-physical properties of the generated surface layers were investigated. There exist significant differences between untreated and laser melted samples, whose possible causes are discussed. 相似文献
124.
M. Meot-Meyer G. Venturini B. MaLaman J. Steinmetz B. Roques 《Materials Research Bulletin》1984,19(9):1181-1186
New ternary stannides are reported : RE2Rh3Sn5 (RE = Y, Gd, Tb, Dy, Ho). Y2Rh3Sn5 has been studied by single - crystal X-ray diffraction analysis. Its structure is of a new type with space group Cmc21 and Z = 4 : a = 4,387(2), b = 26,212(4), , Dx = 8,71 Mgm?3, μ(AgKα) = 17 mm?1, F(000) = 1851, R = 0,045 for 478 independant reflexions (Rw = 0,046). This structure is characterized by a tridimensionnal lattice of RhSn covalent bonds with two very different sites for yttrium. Y2Rh3Sn5 is diamagnetic and semimetallic according to its electrical properties. 相似文献
125.
126.
Untersuchung der gemeinsamen Einflüsse von Nickel und Silizium sowie Chrom und Silizium auf die chemischen Aktivitäten von Kohlenstoff und Sauerstoff im flüssigen Eisen bei 1600°C unter Kohlenmonoxid-Kohlendioxid-Atmosfhäre. Zeichnerische Darstellung der Versuchsergebnisse. Vergleich mit Wirkungsparametern der Randsysteme. 相似文献
127.
Lee PC Mijts BN Petri R Watts KT Schmidt-Dannert C 《Protein engineering, design & selection : PEDS》2004,17(11):771-777
Directed evolution of the C25 farnesylgeranyl diphosphate synthase of Aeropyrum pernix (Fgs) was carried out by error-prone PCR with an in vivo color complementation screen utilizing carotenoid biosynthetic pathway enzymes. Screening yielded 12 evolved clones with C20 geranylgeranyl diphosphate synthase activity which were isolated and characterized in order to understand better the chain elongation mechanism of this enzyme. Analysis of these mutants revealed three different mechanisms of product chain length specificity. Two mutants (A64T and A64V) have a single mutation at the 8th amino acid upstream of a conserved first aspartate-rich motif (FARM), which is involved in the mechanism for chain elongation reaction of all prenyl diphosphate synthases. One mutant (A135T) carries a single mutation at the 7th amino acid upstream of another conserved region (141GQ142), which was recently found to be another important region controlling chain elongation of a type III C20 geranylgeranyl diphosphate synthase and Escherichia coli C15 farnesyl diphosphate synthase. Finally, one mutant carrying four mutations (V84I, H88R, I177 M and M191V) is of interest. Molecular modeling, site-directed mutagenesis and in vitro assays of this mutant suggest that product chain-length distribution can be also controlled by a structural change provoked by a cooperative interaction of amino acids. 相似文献
128.
It has been repeatedly shown earlier that some fish of a given batch reveal motion sickness (a kinetosis) at the transition from 1 g to microgravity. In the course of parabolic aircraft flight experiments, it has been demonstrated that kinetosis susceptibility is correlated with asymmetric inner ear otoliths (i.e., differently weighed statoliths on the right and the left side of the head) or with genetically predispositioned malformed cells within the sensory epithelia of the inner ear. Hitherto, the threshold of gravity perception for inducing kinetotic behaviour as well as the relative importance of asymmetric otoliths versus malformed epithelia for kinetosis susceptibility has yet not been determined. The following experiment using the ZARM drop-tower facility in Bremen, Germany, is proposed to be carried out in order to answer the aforementioned questions. Larval cichlid fish (Oreochromis mossambicus) will be kept in a camcorder-equipped centrifuge during the microgravity phases of the drops and thus receive various gravity environments ranging from 0.1 to 0.9 g. Videographed controls will be housed outside of the centrifuge receiving 0 g. Based on the videorecordings, animals will be grouped into kinetotically and normally swimming samples. Subsequently, otoliths will be dissected and their size and asymmetry will be measured. Further investigations will focus on the numerical quantification of inner ear supporting and sensory cells as well as on the quantification of inner ear carbonic anhydrase reactivity. A correlation between (1) the results to be obtained concerning the g-loads inducing kinetosis and (2) the corresponding otolith asymmetry/morphology of sensory epithelia/carbonic anhydrase reactivity will further contribute to the understanding of the origin of kinetosis susceptibility. Besides an outline of the proposed principal experiments, the present study reports on a first series of drop-tower tests which were undertaken to elucidate the feasibility of the proposal (especially concerning the question, if some 4.7 s of microgravity are sufficient to induce kinetotic behaviour in larval fish). 相似文献
129.
130.
A suite of FORTRAN subroutines/functions to generate data using empirical formulas for physical sputtering of mono-atomic targets for any elemental incident ion (atom), chemical erosion of graphite, Radiation Enhanced Sublimation (RES) of graphite, the number and energy backscattering coefficients for any elemental incident ion (atom) on a compound target and thermal evaporation of graphite is presented. Since chemical erosion, RES and thermal evaporation depend on the surface temperature of graphite, a subroutine implementing the 1-D heat diffusion equation to determine the temperature of any plasma-facing graphite surface is implemented. As an example to illustrate the use of these subroutines/functions, a simple model for the erosion of a plasma-facing surface, consisting of a simple collisionless sheath model, a 1-dimensional steady state heat diffusion model and 0-dimensional steady state particle balance at the target is developed and a sample listing of the program is presented.