Field experiments constraining the probability distribution of particle travel distances during natural rainstorms on different slope gradients     

Afshin Ghahramani  Ishikawa Yoshiharu  Simon M. Mudd 《地球表面变化过程与地形》2012,37(5):473-485

Rain splash erosion is an important soil transport mechanism on steep hillslopes. The rain splash process is highly stochastic; here we seek to constrain the probability distribution of splash transport distances on natural hillslopes as a function of hillslope gradient and total precipitation depth. Field experiments were conducted under natural precipitation events to observe splash travel on varying slope gradients. The downslope fraction of splash transport on 15°, 25° and 33° gradients were 85%, 96% and 96%, respectively. Maximum splash transport (L_max) was related to the rain splash detachment of soil particles and slope gradient. An empirical relationship of L_max to the precipitation depth and gradient was obtained; it is linearly proportional to hillslope gradient and logarithmically related to precipitation depth. Measured splash distances were calibrated to the fully two‐dimensional (2D) model of splash transport of Furbish et al. (Journal of Geophysical Research 112 : F01001, 2007) that is based on the assumption that radial splash distances are exponentially distributed; calibrated values of mean splash transport distances are an order of magnitude greater than those previously determined in a controlled laboratory setting. We also compared measured data with several one‐dimensional (1D) probability distributions to asses if splash transport distances could be better explained by a heavy‐tailed probability distribution rather than an exponential probability distribution. We find that for hillslopes of 15° and 25°, although a log‐normal probability distribution best describes the data, we find its likelihood is nearly indistinguishable from an exponential distribution based on computing maximum likelihood estimators for all 1D distributions (exponential, log‐normal and Weibull). At 33°, however, we find stronger evidence that measured travel distances are heavy‐tailed. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Rapidly rotating superfluid neutron stars in Newtonian dynamics     

Shijun Yoshida  Yoshiharu Eriguchi 《Monthly notices of the Royal Astronomical Society》2004,347(2):575-586

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Spectral lines from photosphere to chromosphere,observed during the March 1970 eclipse; A first comparison with theory     

J. Houtgast  O. Namba  R. J. Rutten  J. W. Wijbenga 《Solar physics》1971,21(2):281-285

A brief report is presented on observations of line profile variations in the transition region from the photosphere to the chromosphere, based on high-resolution eclipse spectrograms. We also show some computations for several lines whose behaviour agrees in general with the observations.  相似文献   

Behaviour of proteinaceous substances in the estuary of the Tama River     

Norio Ogura  Yoshiharu Tanaka  Jun-ichi Itoh  Katsufumi Takahashi 《Journal of Oceanography》1984,40(3):184-191

Behaviour of dissolved and particulate proteinaceous substances in the estuary of the Tama River was investigated through field observations and laboratory experiments. Concentrations of dissolved proteinaceous substances in estuarine water were determined at eight stations between the mouth of the Tama River (TA-15) and a point 16km upstream (TA-8), using the colorimetric method of Lowryet al. (1951) that employs Folin phenol reagent. The results were expressed in terms of Folin phenol active substances (FPAS). It was found that FPAS decreased with increasing salinity and that the proportion of high molecular weight FPAS (molecular weight greater than 100,000) decreased rapidly in the estuary.The shapes, sizes and numbers of amorphous particulate substances stained by Amido Black 10B, called Amido Black active substances (ABAS), were determined under a microscope. The numbers of ABAS retained on Millipore HA filters (mean diameter: 10–80µm) amounted to 450ml^–1 in the estuarine water about 6km from the mouth of the estuary (Station TA-12M). Some of these aggregates are considered to be producedin situ by flocculation of high molecular weight FPAS during estuarine mixing. ABAS were also produced in experiments by mixing filtered river water with sea water.  相似文献   

The runaway instability of self-gravitating tori with non-constant specific angular momentum around black holes     

Nobuyuki Masuda  Shogo Nishida  & Yoshiharu Eriguchi 《Monthly notices of the Royal Astronomical Society》1998,297(4):1139-1144

We discuss the runaway instability of axisymmetric tori with non-constant specific angular momentum around black holes, taking into account self-gravity of the tori. The distribution of specific angular momentum of the tori is assumed to be a positive power law with respect to the distance from the rotational axis. By employing the pseudo-Newtonian potential for the gravity of the spherical black hole, we have found that self-gravity of the tori causes a runaway instability if the amount of the mass which is transferred from the torus to the black hole exceeds a critical value, i.e. 3 per cent of the mass of the torus. This has been shown by two different approaches: (1) by using equilibrium models and (2) by dynamical simulations. In particular, dynamical simulations using an SPH code have been carried out for both self-gravitating and non-self-gravitating tori. For non-self-gravitating models, all tori are runaway stable. Therefore we come to the conclusion that self-gravity of the tori has a stronger destabilizing effect than the stabilizing effect of the positive power-law distribution of the angular momentum.  相似文献   

Abstracts of papers from other journals     

Vassilyeva  G.  Namba  O. 《Solar physics》1974,37(1):264-268

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