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141.
142.
John A. Alwin 《The Professional geographer》1992,44(4):369-376
The ascendance of the Pacific Rim is an indisputable global happening. North American geography, a logical leader in the study of this high profile phenomenon, has lagged behind other disciplines in Rim-focused research. This article argues in favor of a heightened Rim awareness, surveys recent publications, suggests promising Pacific Rim research directions, and proposes how the Association of American Geographers can help promote Rim studies. 相似文献
143.
Ahmet Güllü Ercan Yüksel Cem Yalçın A. Anıl Dindar Hasan Özkaynak Oral Büyüköztürk 《地震工程与结构动力学》2019,48(1):27-45
Input energy is the principal component of the energy balance equation. It is beneficial to determine, through its components, how the recoverable and irrecoverable energies are distributed within the structural elements. Several equations and attenuation relations to define mass-normalized input energy spectra exist in the literature. They are mainly proposed for elastic systems subjected to far-fault EQs. There is a lack of experimental verification of these proposed spectra. In this paper, experimental assessment was performed to the existing spectra, and further improvements were accomplished. For this purpose, steel cantilever columns were tested on the shake table for two specific historical EQs coincidently having similar spectral acceleration values. Based on the experimental results, a three-part mass-normalized relative input energy spectrum was formulated including soil type, EQ (corner period, intensity, duration, spectral acceleration, and velocity), and structural behavioral characteristics (period and structural damping). The proposed input energy spectrum was experimentally calibrated and numerically validated for various EQs featuring near- and far-field types. Analytical and experimental comparisons were made between the previously developed spectrum and the newly proposed one. The validation studies and the statistical evaluations exposed that the proposed spectrum yielded better agreement with the experimental and numerical results. 相似文献
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Lopatin A. V. Golovachev I. V. Serdyuk N. V. Maschenko E. N. Vislobokova I. A. Dac Le Xuan Phuong Pham Mai Parkhaev P. Yu. Syromyatnikova E. V. 《Doklady Earth Sciences》2022,504(2):372-379
Doklady Earth Sciences - Speleological, geological and paleontological characteristics of the Lang Trang cave in northern Vietnam are presented. Primates Gigantopithecus blacki von Koenigswald,... 相似文献
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J. E. Cavanagh K. A. Burns G. J. Brunskill R. J. Coventry 《Marine pollution bulletin》1999,39(1-12):367-375
Organochlorine pesticides were widely used in the Australian sugarcane industry from the early 1950s until the late 1980s. Erosion of sugarcane soils and subsequent transport of sediment bound contaminants in river run-off to the Great Barrier Reef lagoon is a growing concern as the cane industry continues to expand. Organochlorine pesticide residues can be used as tracers to examine the worst-case scenario of the spatial extent to which currently used, though less persistent, organic agricultural pesticides might extend. The coastal alluvial flood-plains of the Herbert and Burdekin Rivers in North Queensland have sugarcane growing as the major coastal land-use. Sediment cores and surface sediment samples were collected from near-shore coastal regions of the Herbert and Burdekin Rivers. In addition, soil samples from cane-fields in the two catchments were collected. Analyses of the marine surface sediment samples and three sediment cores revealed the absence of detectable concentrations of organochlorine pesticides (<5 pg/g). However, easily detectable concentrations were found in the sugarcane soil samples (0.01–45 ng/g). 相似文献
150.
S. A. Mouritsen 《International Journal of Earth Sciences》1966,55(3):856-878
Geology must consider the physical processes involved in the genesis of inorganic matter. These processes are ultimately based on cosmogony and cosmology and the associated physics and mathematics of these origins.The approach to genesis impinges on the unknown where a feeling that something finite, and possibly real, exists. The evidence of the unknown must then be compared with the experimental and observed evidence to create a framework from which certain conclusions can be made.The thoughts on genesis and the geological implications are discussed briefly in two parts. Part one includes the basic philosophy, the mathematical and physical concepts; it outlines the philosophy of time, zero and infinity, mass, space, and the mass environments, based on this a ring hypothesis of planetary origins is developed. Part two discusses basic problems of structural geology, fundamental tectonics, the development of continents and continental drift, climatic changes, seismicity, and paleomagnetics.The conclusions drawn from the discussion are: mass ormatter can exist in five states. Continental buttresses are largely made up of rocks of secondary igneous origin. The core of the earth is made of solar (meteoric) material rather than pure nickel-iron. Continents move under differential density forces which ultimately result in a slow twist or rotation of the earth's outer layers about the core. This rotation causes climatic changes and the many paths observed in tracing polar wandering by paleomagnetics.
Zusammenfassung Dieser Aufsatz versucht, fundamentale geologische Grenzprobleme in Beziehung zu bringen mit fundamentaien physikalischen und astronomischen Problemen, die ihrerseits z. T. noch einer Lösung harren.Ausgehend von einer Betrachtung der Herkunft von Masse, Universum und Sonnensystem werden Probleme der Kontinentalgenese, Kontinentalwanderung, hydrostatischer Druck auf und in Kontinenten, Orogenese, Klimaänderungen und Paläomagnetik in geologischer Zeit besprochen.Der Aufsatz besteht aus zwei Teilen, einem physikalischen und einem geologischen, die zu einem gewissen Grade unabhängig voneinander gelesen werden können. Für ein fruchtbares Verstehen ist es aber ratsam, beide Teile zu lesen. Mathematik ist auf das notwendigste beschränkt.Am Ausgangspunkt der Betrachtung steht die Idee von einem fundamentalen (letztlichen) Masse-Medium, da dieses die Grenze der Erkenntnis bildet.
Résumé La géologie doit considérer le processus physique entraîné dans la genèse de matière inorganique. Ce processus est finalement basé sur la cosmogonie et cosmologie, ainsi que la physique associée et mathématiques de ces originesL'approche de la genèse se heurte à l'inconnu où le sentiment de quelque chose de fini et peut-être bien réel existe. L'évidence de l'inconnu doit alors être comparée à l'évidence expérimentale et observée, pour créer une structure de laquelle certaines conclusions peuvent être tirées.Les réflexions sur la genèse et les implications géologiques sont exposées brièvement en deux parties. La première partie comprend la philosophie fondamentale, les idées générales de mathématique et physique; elle esquisse la philosophie du temps, zéro et infini, masse, espace et environnements de la masse; basée là-dessus, une hypothèse en cercle des origines planétaires est développée. La seconde partie expose les problèmes fondamentaux de géologie structurale, tectoniques fondamentales, le développement des continents et le mouvement de ceux-ci, changements de climat, séismicité et paléomagnétiques.Les conclusions tirées de l'exposé sont que masse ou matière peuvent exister dans cinq états. Les contreforts continentaux sont en grande partie formés de roche pyrogène secondaire. Le noyau de la terre est fait de matière solaire (météorique) plutôt que de nickel-fer pur. Les continents se déplacent sous des forces de densité différentielle qui résultent finalement dans une torsion lente ou rotation des couches extérieures de la terre autour du noyau. Cette rotation provoque des changements climatique et les nombreuses voies observées en traçant les écarts polaires par paléomagnétique.
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