RANK-ORDER ANALYSIS FOR ROBUST MULTIRESPONSE,MULTIBLOCK COMPARISONS:EVALUATION OF HERBICIDE INTERACTIONS     

DAVID LEE DUEWER  ROBERT D.CLARK 《地理学报(英文版)》1991,(6)

Studies of interactions among bioactive compounds are often difficult to interpret unambiguously.A priori assumptions about the nature of such interactions can seriously distort analysis of the data.Byapplying a rank order analysis appropriate to the naturally ordinal scale of response to xenobiotic insult,several co-herbicides were successfully identified from among numerous candidates in an experimentinvolving multiple blocks,rates and species.Moreover,underlying herbicide interactions weresubstantiated and identified which were not apparent by more traditional parametric analysis.  相似文献   

Synoptic interpretation of seismic reflection and refraction data     

St. Mueller  J. Ansorge  N. Sierro  P. Finckh  D. Emter 《Geophysical Journal International》1987,89(1):345-352

Summary. The structure of the upper lithosphere beneath southern Germany, northern Switzerland and west-central Utah (U.S.A.) has been investigated in detail by various geophysical methods. A synoptic interpretation of travel time and amplitude data obtained in seismic refraction and wide-angle reflection surveys, combined with near-normal incidence reflection observations, now permits the elucidation of the fine structure in a more quantitative and unified manner. With this scheme it is possible to unambiguously identify low-velocity zones and to deduce velocity gradients if reliable amplitude information is included in the inversion process.  相似文献   

Anomalous Cosmic-Ray Helium,Nitrogen and Oxygen in 1996 – Measurements of the ERNE Instrument on-board SOHO     

Torsti  J.  Valtonen  E.  Anttila  A.  Vainio  R.  Mäkelä  P.  Riihonen  E.  Teittinen  M. 《Solar physics》1997,170(1):193-204

The energy spectra of the anomalous components of helium, nitrogen and oxygen have been measured by the ERNE experiment on board the SOHO spacecraft. During February 28–April 30, 1996, the maximum intensity of anomalous helium was found to be 3.8 × 10^-5 cm^-2 sr^-1 s^-1 (MeV nucl^-1)^-1 in the energy range 10–15 MeV nucl^-1. During the period January 26–April 30, 1996, the maximum oxygen intensity was 1.2 × 10^-5 cm^-2 sr^-1 s^-1 (MeV nucl^-1)^-1 at 4–7 MeV nucl^-1, and the maximum nitrogen intensity 1.7 × 10^-6 cm^-2 sr^-1 s^-1 (MeV nucl^-1)^-1 at 4–9 MeV nucl^-1. These peak intensities are at the same level as two solar cycles ago in 1977, but significantly higher than in 1986. This gives observational evidence for a 22-year solar modulation cycle. A noteworthy point is that the spectra of anomalous nitrogen and oxygen appear to be somewhat broader than in 1977.  相似文献   

Numerical simulations of collisions in Keplerian systems     

K. A. Hämeen-Anttila  J. Lukkari 《Astrophysics and Space Science》1980,71(2):475-497

Computer simulations which were carried out for Keplerian collisional systems of 250 frictionless particles with a ratio of particle radius to mean semi-major axis of 0.001, confirm the theoretically predicted evolution very well until the thickness of the system is a few times the particle radius and the mass-point approximation becomes invalidated. Before this happens, the collisional contraction of denserregions can be observed. The local dispersions of the perihelia and ascending nodes diminish if the local mean orbit is not too close to a circle with zero inclination. When the mass-point approximation ceases to be valid, the system begins to expand, but with parameter values of our standard system this process is much slower than the simultaneously observed evolution toward grazing collisions which do not affect the orbital elements. Therefore, such systems are not dispersed into the space. If the ratio of particle radius to semi-major axis is larger, the expansion becomes faster and the contraction ceases earlier. In late evolutionary phases the thickness of the system remains essentially constant. At the end of the longest simulation (70 000 impacts) the centres of the particles were in a layer of thickness twice the radius of the particles. The cross-section of the system is often wave-like or irregular and may even include detached parts with their own mean plane. Accordingly the thickness as derived from the root-mean-square inclination of the whole system exceeds the true local thickness. The local dispersion of eccentricities may also be considerably smaller than the root-mean-square eccentricity of the whole system.  相似文献   

Hydrographische Bibliographie     

Fr. Model  H. Mädler 《Ocean Dynamics》1967,20(5):233-248

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Problems related to macroscopic electric fields in the magnetosphere     

Carl-Gunne Fälthammar 《Astrophysics and Space Science》1978,55(1):179-201

The macroscopic electric fields in the magnetosphere originate from internal as well as external sources. The fields are intimately coupled with the dynamics of magnetospheric plasma convection. They also depend on the complicated electrical properties of the hot, collisionless plasma. Macroscopic electric fields are responsible for some important kinds of energization of charged particles that take place in the magnetosphere and affect not only particles of auroral energy but also, by multistep processes, trapped high-energy particles.A particularly interesting feature of magnetospheric electric fields is the fact that they can have substantial components along the geomagnetic field. Several physical mechanisms have been identified by which such electric fields can be supported even when collisions between particles are negligible. Comments are made on the magnetic-mirror effect, anomalous resistivity, collisionless thermoelectric effect and electric double layers, emphasizing key features and differences and their significance in the light of recent observational data.Paper dedicated to Professor Hannes Alfvén on the occasion of his 70th birthday, 30 May, 1978.Reprinted, with due permission fromRev. Geophys. Space Phys. 15, (1977), 457  相似文献   

Neutron capture cross-sections of stable xenon isotopes and their application in stellar nucleosynthesis     

H. Beer  F. Käppeler  G. Reffo  G. Venturini 《Astrophysics and Space Science》1983,97(1):95-119

The neutron capture cross-sections of^{124, 132, 134}Xe have been measured by the activation technique at 25 keV neutron energy. These data were supplemented by calculated capture cross-sections for^{128, 129, 130, 131}Xe via the statistical model. The complete set of capture cross-sections obtained in this way served to determine the solar xenon abundance throughs-process systematics and to study a variety of isotopic anomalies.  相似文献   

Dust in turbulent circumstellar discs     

M. Verronen  H. Vanhala  K. A. Hämeen-Anttila 《Astrophysics and Space Science》1993,200(1):75-89

The collisional model for turbulent discs (Hämeen-Anttila, 1991) is shown to be equivalent to the model if the same coefficient of viscosity is adopted in both cases and if an unknown numerical coefficient in the former model is chosen appropriately. A combination of both approximations is generalized to include the behaviour of dust in the turbulent disc. If the dust grains are not too large, evolution leads to a stable final state having a non-zero temperature. Physical interpretation of the collisional model leads to a new type of turbulence, in which, if a sufficiently large element of gas is randomly displaced even in a stable disc, the resulting oscillations around the equilibrium position are maintained by the orbital energy. This effect produces an irregular wind of 10 to 100 m s^–1 which is sufficient to prevent the sedimentation of dust grains on the equatorial plane.  相似文献   

Low differential stress and controlled chemical environment in multianvil high-pressure experiments     

D. C. Rubie  S. Karato  H. Yan  H. St. C. O'Neill 《Physics and Chemistry of Minerals》1993,20(5):315-322

Studies of mass transport and kinetics in minerals at high pressure often require a sample environment in which the stress is near-hydrostatic and the chemical environment is carefully controlled. We report here details of a multianvil sample assembly in which these requirements are fulfilled and which has been used to study the effect of pressure on the kinetics of dislocation recovery in olivine up to 10 GPa. Annealing experiments have been performed on single crystals of San Carlos olivine at 8.5 GPa and 1400° C in a 1200 tonne split-sphere multianvil apparatus. The sample assembly consists of an 18 mm MgO octahedron with a LaCrO₃ heater of variable wall thickness to give a small temperature variation (20° C) along the 3 mm length of the sample capsule. To minimize the differential stress on the sample, the olivine single crystal is surrounded by NaCl and both pressurization and depressurization are performed slowly at a temperature of 600° C (to minimize the strength of the NaCl). The silica activity is buffered by orthopyroxene powder in contact with the olivine and the oxygen fugacity is buffered by Ni + NiO within the sample capsule. The H₂O-content of the sample assembly is minimized by drying all components at 230° C under vacuum. Olivine single crystals recovered after annealing at 1400° C and 8.5 GPa show no evidence of deformation, either ductile or brittle. Dislocation densities of 10⁹–10¹⁰ m^-2 are similar to those observed prior to high-pressure annealing and indicate differential stresses of <10 mpa.=" infrared=" spectroscopy=" indicates=" that=" the=" hydrogen=" content=" of=" a=" sample=" annealed=" at=" 10=" gpa,=" 1500°=" c=" for=" 21=" h=" is=">13 H/10⁶Si, which, although low, is higher than that of the crystals prior to high-pressure annealing. Finally, the effectiveness of the fO₂ buffer has been verified by estimating the fO₂ at the surface of the sample from the solubility of Fe in Pt metal in equilibrium with the olivine and orthopyroxene.  相似文献   

The flare of December 17, 1980 observed with high time resolution by a digital CCD camera     

N. Kämpfer  W. Schöchlin 《Solar physics》1982,78(2):215-224

An electro-optical system for the digital registration of H-images with high time resolution (1.6 s) is described. The sensor is a Charge-Coupled-Device (CCD) with 100 × 100 elements, resulting in our case in a resolution of 3 × 4 on the Sun. Data are digitized with a resolution of 8 bit and written on magnetic tape by means of a minicomputer. Image analysis on a large computer eliminates instrumental effects, calibrates the data and reproduces them in graphical form. The analysis of a first flare (December 17, 1980; 12:09 UT) shows that the different flare kernels brighten at different times and pulsate in diameter and intensity. The decay of the flare is slower if fainter regions are included. This supports the idea that an impulsive flare confined in a magnetic loop spreads out over a larger area during the gradual phase. Comparison with microwave observations shows the same risetime for both spectral ranges which indicates that they are excited by the same agent. Furthermore the H-flare lags the microwave burst by about 8 s indicating that the source of primary energy release lies above the H emitting layers.  相似文献