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Journal of Palaeogeography 2018年第3期7卷 197-238页

作者： g.Shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

Sedimentologic, oceanographic, and hydraulic engineering publications on hyperpycnal flows claim that （1） river flows transform into turbidity currents at plunge points near the shoreline, （2） hyperpycnal flows have the power to erode the seafloor and cause submarine canyons, and, （3） hyperpycnal flows are efficient in transporting sand across the shelf and can deliver sediments into the deep sea for developing submarine fans. Importantly, these claims do have economic implications for the petroleum industry for predicting sandy reservoirs in deep-water petroleum exploration. However, these claims are based strictly on experimental or theoretical basis, without the supporting empirical data from modern depositional systems. Therefore, the primary purpose of this article is to rigorously evaluate the merits of these claims. A global evaluation of density plumes, based on 26 case studies （e.g., Yellow River, Yangtze River, Copper River, Hugli River （ganges）, guadalquivir River, Rio de ]a Plata Estuary, Zambezi River, among others）, suggests a complex variability in nature. Real-world examples show that density plumes （1） occur in six different environments （i.e., marine, lacustrine, estuarine, lagoon, bay, and reef）; （2） are composed of six different compositional materials （e.g., siliciclastic, calciclastic, planktonic, etc.）; （3） derive material from 11 different sources （e.g., river flood, tidal estuary, subglacial, etc.）; （4） are subjected to 15 different external controls （e.g., tidal shear fronts, ocean currents, cyclones, tsunamis, etc.）; and, （5） exhibit 24 configurations （e.g., lobate, coalescing, linear, swirly, U-Turn, anastomosing, etc.）. Major problem areas are：（1） There are at least 16 types of hyperpycnal flows （e.g., density flow, underflow, high-density hyperpycnal plume, high-turbid mass flow, tide-modulated hyperpycnal flow, cyclone-induced hyperpycnal turbidity current, multi-layer hyperpycnal flows, etc.）, without an underpinning principle of flu

关键词： Density plumes Facies model Hyperpycnites Submarine fans Tidal shear fronts Ocean currents Turbiditycurrents Yellow River Yangtze River

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Breakdown process on rod–rod air gap under oscillating lightning impulse voltage

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High Voltage 2020年第3期5卷 319-326页

作者： Akif gürlek Faculty of Electrical Engineering and Information Technology Professorship of Power Systems and High-Voltage EngineeringTechnische Unversität ChemnitzReichenhainer Strasse 70D-09126 ChemnitzGermany

This study presents the discharge process on rod–rod electrodes under oscillating lightning impulse *** this purpose,a measurement system has been developed to record the discharge currents at both rod electrodes simultaneously and to photograph the spatial propagation of the *** measurement results of the discharge process are shown for an air gap of s=150 cm and for a superimposed frequency of f=200 *** the standardised lightning impulse voltage,three consecutive phases of discharge have been identified before a breakdown *** are streamer discharge phase,channel transition phase and channel formation *** three phases are described,interpreted and their correlation is *** the basis of the oscillations,the discharge processes recur periodically if the momentary voltage is higher than the mean curve of the oscillating lightning impulse *** streamer discharge emerges foremost at the positive rod electrode and propagates toward the grounded rod *** propagation depends on the voltage crest *** at the grounded rod electrode,the channel transition phase *** the discharge moves back to the positive rod electrode due to recombination and *** the discharge constricts to the positive rod electrode,which forms a ***,at the grounded rod electrode,a channel is also *** each period,the channel will build up *** channel leads to the main discharge of the oscillating lightning impulse voltage.

关键词： oscillating electrode lightning

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Shell-model representations of the microscopic version of the Bohr-Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 79-90页

作者： H g ganev Joint Institute for Nuclear Research DubnaRussia Institute of Mechanics Bulgarian Academy of SciencesSofiaBulgaria

The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in *** chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective *** construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass *** is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)*** is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm *** the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard *** results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model Sp(12,R)dynamical algebra shell-model representations

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Reply to discussions by Zavala(2019) and by Van Loon, Hüeneke, and Mulder(2019)on Shanmugam, g.(2018, Journal of Palaeogeography, 7(3): 197–238): ‘the hyperpycnite problem’

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Journal of Palaeogeography 2019年第4期8卷 408-421页

作者： g.Shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

In this reply,I respond to 18 issues associated with comments made by Zavala(e.g.,inverse-to normally-graded sequence,origin of massive sands,experimental sandy debris flows,tidal rhythmites,facies models,etc.),and 10 issues associated with comments made by Van Loon et al.(e.g.,16 types of hyperpycnal flows,anthropogenic hyperpycnal flow,etc.).

关键词： Hyperpycnal flows Hyperpycnites Sandy debris flows Turbidity currents

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The application of open standards to enhance the interoperability of geoscience information

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International Journal of Digital Earth 2010年第S1期3卷 14-30页

作者： g.Percivall Open geospatial Consortium HerndonVAUSA

We can adequately study broad global issues and policies only by taking geosciences into *** research and decision-making must share and make effective use of interdisciplinary data sources,models,and *** impedes sharing of data and computing *** from the Open geospatial Consortium(OgC)and other organizations are the basis for successfully deploying a seamless,distributed information infrastructure for the *** specifications now adopted by the OgC consensus process are the result of OgC interoperability *** OgC standards,deployment architectures,and interoperability initiatives are described showing how the OgC standards baseline has been developed and applies to the geosciences.

关键词： geosciences interoperability open standards Open geospatial Consortium geoinformatics geospatial data integration Digital Earth architecture spatial data infrastructure data exchange models

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The fallacy of interpreting SSDS with different types of breccias as seismites amid the multifarious origins of earthquakes:Implications

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Journal of Palaeogeography 2017年第1期6卷 12-44页

作者： g.Shanmugam Department of Earth and Environmental Sciences The University of Texas at ArlingtonArlingtonTX 76019USA

At present, there are no criteria to distinguish soft-sediment deformation structures （SSDS） formed by earthquakes from SSDS formed by the other 20 triggering mechanisms （see a companion paper in Vol 5, No. 4 of this journal by Shanmugam, 2016）. Even if one betieves that earthquakes are the true triggering mechanism of SSDS in a given case, the story is stiff incomptete. This is because earthquakes （seismic shocks） are induced by a variety of causes： 1） glbaltectonics and associated faults （i.e., midocean ridges, trenches, and transform fautts）; 2） meteorite-impact events; 3） volcanic eruptions; 4） post-gtacialuplift; 5） tsunami impact; 6 cyclonic impact; 7） landslides （mass-transport deposits）; 8） tidal activity; 9） sea-tevet rise; 10） erosion; and 11） fluid pumping. These different causes are important for devetoping SSDS. Breccias are an important group of SSDS. Although there are many types of breccias classified on the basis of their origin, five types are discussed here （fault, volcanic, meteorite impact, sedimentary-depositionaL, sedimentary-collapse）. Atthough different breccia types may resemble each other, distinguishing one type （e.g., meteorite breccias） from the other types （e.g., fault, volcanic, and sedimentary breccias） has important imptications. 1） Meteorite breccias are characterized by shock features （e.g., planar deformation features in mineral grains, planar fractures, high-pressure polymorphs, shock melts, etc.）, whereas sedimentary- depositional breccias （e.g., debrites） do not. 2） Meteorite breccias imply a confined sediment distribution in the vicinity of craters, whereas sedimentary-depositional breccias imply an unconfined sediment distribution, variable sediment transport, and variable sediment provenance. 3） Meteorite, volcanic, and fault breccias are invariabty subjected to diagenesis and hydrothermat mineratization with attered reservoir quality, whereas sedimentary-depositional breccias exhibit primary （unaltered） reservoir quality.

关键词： Breccias Earthquakes Faults global tectonics Meteorite impacts Seismites Soft-sedimentdeformation structures (SSDS)

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Ce anomaly in minerals of eclogite and garnet pyroxenite from Dabie-Sulu ultrahigh pressure metamorphic belt:Tacking subducted sediment formed under oxidizing conditions

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Science China Earth Sciences 2004年第10期47卷 920-930页

作者： Deltlef günther Institute of Inorganic Chemistry ETHZürichUniversitatsstrasse6CH-092ZürichSwitzerland

In-situ excimer laser ICP-MS analysis of minerals of eclogites and garnet pyrox- enites from type localities (Shuanghe, Maowu, Bixiling, and Yangkou) in the Dabie-Sulu ultra- high-pressure metamorphic belt reveals highly variable Ce anomalies from negative to positive in garnet. Similar Ce anomalies are also present in omphacite or clinopyroxene but to a much lesser extent. Such mixed negative and positive Ce anomalies mimic those found in severe weathering profiles developed under oxidizing conditions. They suggest the presence of sub- ducted sediment components in the eclogites and garnet pyroxenites, which in turn points to the potential importance of the recycled sediments in modification of the mantle composition during the deep subduction of the continental crust.

关键词： Dabie-Sulu, eclogite, garnet pyroxenite, LA-ICP-MS, subducted sediment, Ce anomaly.

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Seasonal Variation of Cumulative CO_2 Emission from a Vertisol Under Apricot Orchard in Semi-Arid Southeast Turkey

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Pedosphere 2012年第3期22卷 322-332页

作者： g.YILMAZ Department of Environmental Engineering Harran UniversityS anliurfa 63100 (Turkey)

Understanding the factors affecting the CO 2 emission from agricultural practices is crucial for global warming.A study was performed in an apricot orchard field in the experimental farm of the Harran University,Southeast Turkey,to i) quantify weekly and seasonal variations of the CO 2 emissions from a Vertisol under apricot orchard;ii) evaluate the difference in CO 2 emission between the area under trees and rows;and iii) assess the relationships between the amounts of CO 2 emissions and environmental parameters for better use and management of the soils from the view point of carbon balance and flux in a semi-arid environment under drip *** CO 2 emission measurements were performed during May 2008 and May 2010,from both under tree crowns (CO 2-UC) and between tree rows (CO 2-BR),on a weekly basis in southeast Turkey with a semi-arid *** 2 emissions were statistically correlated with weather and soil parameters such as air temperature,relative humidity,rainfall,soil water content,and soil temperature at various depths from 5 to 100 *** weekly emissions ranged from 82 to 1 110 kg CO 2 ha 1 week 1 and from 96 to 782 kg CO 2 ha 1 week 1 in CO 2-UC and CO 2-BR,*** in CO 2 emission in the second year was due to increases in mean air and soil *** weekly and monthly cumulative CO 2 emissions were positively correlated with the air and soil *** linear regression analysis explained 35% and 83% variations in average weekly and monthly CO 2 emissions,by using meteorological *** the interaction effects of meteorological parameters in regression equations nearly doubled the variance explained by the regression *** to stepwise regression analysis,soil and air temperatures were found to have the most significant impact on the temporal variability of the soil CO 2 emission.

关键词： global warming meteorological data plowing soil temperature stepwise regression

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Inverse dynamics and servomotor parameter estimation of a 2-DOF spherical parallel mechanism

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Science China(Technological Sciences) 2008年第3期51卷 288-301页

作者： D g CHETWYND School of Engineering The University of Warwick

A novel reconfigurable 5-DOF hybrid manipulator―TriVariant-B is composed of a 2-DOF spherical parallel mechanism which is serially connected with a 3-DOF open-loop kinematic chain undergoing one translation and two rotations by a prismatic joint. The merit of this design is that a relatively large workspace/limb- stroke ratio can be achieved thanks to the decomposition of the fixed point rotation and the relative translation. In this paper, on the basis of inverse dynamic formula- tion of the 2-DOF spherical parallel mechanism, an approach is proposed for esti- mating the servomotor parameters including moment of inertia, rated speed and the maximum torque in a quick manner. The approach has been employed for the development of a prototype for frame cutting process.

关键词： parallel kinematic machine inverse dynamics servomotor parameters

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Permian–Triassic Charophytes: Distribution, Biostratigraphy and Biotic Events

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Journal of Earth Science 2018年第4期29卷 778-793页

作者： Spencer g Lucas New Mexico Museum of Natural History 1801 Mountain Road N. W. Albuquerque New Mexico 87104 USA

Permian charophytes are known from the Ukraine, Russia, Kazakhstan, germany, Saudi Arabia, China, the USA, Brazil, Paraguay and India. Most of these records are of Middle- Late Permian Age and are the basis of local biostratigraphic zonation in southern Russia and China. Development of a robust Permian charophyte biostratigraphy will require a more extensive record. Triassic charopbytes are known from germany, Sweden, Poland, Slovenia, Bulgaria, the Ukraine, Russia, Morocco, Congo, the USA, Argentina, Kazakhstan and China. This encompasses records from all Triassic stages and has been the basis of detailed biostratigraphic zonation in southern Russia-Kazakhstan-eastern Europe. Permian and Triassic charophyte biostratigraphy at the level of genus does not provide detailed correlations beyond local or regional schemes. Nevertheless, it does identify some important evolutionary datums that constrain the timing of important biotic events in the Permian-Triassic evolutionary history of the Charophyta, including：（1） Early Permian extinction of the Palaeocharaceae; （2） Late Permian extinction of the ＂Trochiliscales＂（Moellerinales）; （3） Carboniferous origin of the paraphyletic Porocharaceae, soon followed during the Permian by the origin of the multicellular basal plate; and （4） an important generic turnover of charophytes across the Triassic-Jurassic boundary, though there are insufficient data to identify this as a mass extinction.

关键词： Permian Triassic charophytes biostratigraphy biotic events.

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