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101.
Please?refer?to?the?attachment(s)?for?more?details. 相似文献
102.
This paper discusses numerical results from three-dimensional large eddy simulations of an oscillating cylinder under prescribed movements in uniform flow. Six cases,namely pure in-line,pure cross-flow and two groups of 'Figure of Eight' oscillation patterns are under investigation at Reynolds number Re=24000. The 'Figure of Eight' pattern in each group is with identical shape but opposite orbital directions. The numerical results on hydrodynamic forces,higher order force components,and vortex shedding mode... 相似文献
103.
Approaches for delineating landslide hazard areas using different training sites in an advanced artificial neural network model 总被引:10,自引:0,他引:10
The current paper presents landslide hazard analysis around the Cameron area, Malaysia, using advanced artificial neural networks
with the help of Geographic Information System (GIS) and remote sensing techniques. Landslide locations were determined in
the study area by interpretation of aerial photographs and from field investigations. Topographical and geological data as
well as satellite images were collected, processed, and constructed into a spatial database using GIS and image processing.
Ten factors were selected for landslide hazard including: 1) factors related to topography as slope, aspect, and curvature;
2) factors related to geology as lithology and distance from lineament; 3) factors related to drainage as distance from drainage;
and 4) factors extracted from TM satellite images as land cover and the vegetation index value. An advanced artificial neural
network model has been used to analyze these factors in order to establish the landslide hazard map. The back-propagation
training method has been used for the selection of the five different random training sites in order to calculate the factor’s
weight and then the landslide hazard indices were computed for each of the five hazard maps. Finally, the landslide hazard
maps (five cases) were prepared using GIS tools. Results of the landslides hazard maps have been verified using landslide
test locations that were not used during the training phase of the neural network. Our findings of verification results show
an accuracy of 69%, 75%, 70%, 83% and 86% for training sites 1, 2, 3, 4 and 5 respectively. GIS data was used to efficiently
analyze the large volume of data, and the artificial neural network proved to be an effective tool for landslide hazard analysis.
The verification results showed sufficient agreement between the presumptive hazard map and the existing data on landslide
areas. 相似文献
104.
Shan-Jie Qian S. Britzen A. Witzel T. P. Krichbaum Heng-Qian Gan Long Gao 《天文和天体物理学研究(英文版)》2014,(3):249-274
The kinematics of superluminal components in blazar 3C 454.3 are studied.Nine components are included:superluminal knots R1,R2,R3,R4,A,B,C and D(from Britzen et al.2013) and C4(from Pauliny-Toth 1998).We find that their kinematics derived from VLBI observations can be consistently interpreted in terms of a jet precession scenario with a period of about 14.5 yr.We discuss the model fits of their trajectory,distance from the core and apparent velocity.We show that the bulk Lorentz factor(in the range 4 to 15) derived for these components does not have any dependence on the phase of the precession(or position angle for ejection).The LenseThirring effect is assumed to interpret the precession of the jet nozzle.The results obtained for blazar 3C 454.3 are only suggestive.They are not unique and have yet to be tested,but they might be useful for understanding the kinematics of superluminal components in blazars and for disentangling different mechanisms and factors. 相似文献
105.
Jayant V.Narlikar 《天文和天体物理学研究(英文版)》2015,(1):1-14
Beginning with his student days at school and college, the author describes his training at Cambridge with special emphasis on his mentor Fred Hoyle. His early experience of participating in a controversy at Cambridge played a major role in giving him the confidence to defend his scientific ideas. All through his later life he chose areas that were not part of mainstream research. These included the steady state theory and later the quasi steady state cosmology, action at a distance, noncosmological redshifts, quantum conformal cosmology, etc. After being a founding member of the Institute of Theoretical Astronomy(IOTA) at Cambridge, the author joined the Tata Institute of Fundamental Research(TIFR) in Mumbai and later moved to Pune to set up the Inter-University Centre for Astronomy and Astrophysics(IUCAA). He briefly reviews his own work and ends by pointing out the difficulties a non-conformist scientist faces in his professional life. In the conclusion, he mentions his interests in science popularization and science fiction for which he has won awards and appreciation, including UNESCO’s Kalinga Prize. 相似文献
106.
Robert G.Strom Renu Malhotra Zhi-Yong Xiao Takashi Ito Fumi Yoshida Lillian R Ostrach 《天文和天体物理学研究(英文版)》2015,(3):407-434
We review previously published and newly obtained crater size-frequency distributions in the inner solar system. These data indicate that the Moon and the terrestrial planets have been bombarded by two populations of objects. Population 1,dominating at early times, had nearly the same size distribution as the present-day asteroid belt, and produced heavily cratered surfaces with a complex, multi-sloped crater size-frequency distribution. Population 2, dominating since about 3.8–3.7 Gyr,had the same size distribution as near-Earth objects(NEOs) and a much lower impact flux, and produced a crater size distribution characterized by a differential –3single-slope power law in the crater diameter range 0.02 km to 100 km. Taken together with the results from a large body of work on age-dating of lunar and meteorite samples and theoretical work in solar system dynamics, a plausible interpretation of these data is as follows. The NEO population is the source of Population 2 and it has been in near-steady state over the past ~ 3.7–3.8 Gyr; these objects are derived from the main asteroid belt by size-dependent non-gravitational effects that favor the ejection of smaller asteroids. However, Population 1 was composed of main belt asteroids ejected from their source region in a size-independent manner, possibly by means of gravitational resonance sweeping during orbit migration of giant planets;this caused the so-called Late Heavy Bombardment(LHB). The LHB began some time before ~3.9 Gyr, peaked and declined rapidly over the next ~ 100 to 300 Myr,and possibly more slowly from about 3.8–3.7 Gyr to ~2 Gyr. A third crater population(Population S) consisted of secondary impact craters that can dominate the cratering record at small diameters. 相似文献
107.
Ruth GEEN Marianne PIETSCHNIG Shubhi AGRAWAL Dipanjan DEY F.Hugo LAMBERT Geoffrey K.VALLIS 《大气科学进展》2023,(11):2029-2052
The East Asian Summer Monsoon(EASM) provides the majority of annual rainfall to countries in East Asia.Although state-of-the-art models broadly project increased EASM rainfall, the spread of projections is large and simulations of present-day rainfall show significant climatological biases. Systematic evapotranspiration biases occur locally over East Asia, and globally over land, in simulations both with and without a coupled ocean. This study explores the relationship between evapotranspiration... 相似文献
108.
109.
P. Ramesh CHANDRA PHANI 《《地质学报》英文版》2016,90(Z1):191-191
正Utility of geochemistry in mineral exploration is known since more than half-a-century.In reconnaissance diamond exploration,regolith geochemistry is a well known tool worldwide and helps in distinguishing bedrock 相似文献
110.
The grid DEM(digital elevation model) generation can be from any of a number of sources:for instance,analogue to digital conversion of contour maps followed by application of the TIN model,or direct elevation point modelling via digital photogrammetry applied to airborne images or satellite images.Currently,apart from the deployment of point-clouds from LiDAR data acquisition,the generally favoured approach refers to applications of digital photogrammetry.One of the most important steps in such deployment i... 相似文献