检索结果-南通市图书馆

vegetation cover of the lahar valley on the Sarychev Peak volcano(Matua Isl.,Middle Kuril Islands) after the Eruption in 2009: current state and features of succession processes

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2021年第7期18卷 1762-1777页

作者： Fedor A.ROMANYUK alexander v.KORDYUKOv Institute of Marine Geology and Geophysics Far East Branch Russian Academy of Sciences693022Yuzhno-SakhalinskNauki Street1bSakhalin regionRussia

The paper presents the study of the vegetation recovery after the descent of the lahar during the eruption of the Sarychev Peak volcano(Matua Isl.,Middle Kuriles) in *** works were carried out in *** was found that during the secondary succession,plant communities,typical of the altitudinal zonation of the volcanic structure vegetation,are formed on lahar sediments in the following manner: the upper sections of the slope are occupied by sparse meadow and shrub vegetation,the middle are presented by shrub belt with a developed canopy,and the lower are representative of shrub large-grass *** the same time,the ordination analysis of the vegetation cover of the lahar valley by the detrended correspondence analysis(DCA) revealed the dispersion of the counting areas along the altitudinal *** is opposite to that characteristic for both,the background communities on the slopes of the studied volcanic structure,and for communities in dynamical equilibrium of a typical altitude ***,directly correlating indicators of α-diversity of communities indicate the presence of open young communities at the stage of a complex *** the species Duschekia fruticosa which is an identifier in buried sites,forms communities in a state of dynamic equilibrium,with individuals of 40–50 years old,and at the time of the work,formed a canopy with individuals of 7–8 years old,a complete recovery of the communities of the lahar valley is possible in no less than 40 *** acquired data on the recovery of vegetation on lahar contribute to the study of succession processes in the sites located in the zone of active *** addition,in this work,for the first time,the rates of restoration of the vegetation cover following its destruction as a result of burial by lahar products,are *** specific features of this process are also *** the broad range of mathematical methods for quantitative analysis of indicators of young commun

关键词： Sarychev Peak volcano Lahar Plant communities Secondary succession Indirect ordination Correlation analysis Shannon-Weaver index of biodiversity Simpson S dominance

Influence of Pt/Pd state on ceria-based support in CO oxidation

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2023年第12期41卷 1963-1968,I0005页

作者： Igor v.Zagaynov Elena Yu.Liberman alexander v.Naumkin A.A.Baikov Institute of Metallurgy and Materials Science MoscowRussia D.I.Mendeleev University of Chemical Technology of Russia MoscowRussia A.N.Nesmeyanov Institute of Organoelement Compounds MoscowRussia

Noble metal(M:Pt,Pd,PtPd) supported on ceria system catalysts were *** oxidized and reduced forms of the active component were examined in CO *** catalysts become more active after a reduction pretreatment,which shifts the temperature of CO *** of the data obtained from characterization techniques indicates that the strong interaction of metal ions with the support prevent the reduction of the initial MO_(x)to metallic *** formation of M-ceria interfaces efficiently boosts the oxygen activation during CO oxidation,leading to the formation of chemisorbed O on M and the regeneration of the ceria lattice oxygen,thus greatly improving the catalytic performance.

关键词： Ceria Platinum Palladium CO oxidation Rare earths

A simple semiempirical model for the static polarizability of electronically excited atoms and molecules

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第4期32卷 290-301页

作者： alexander S Sharipov Alexey v Pelevkin Boris I Loukhovitski Central Institute of Aviation Motors Aviamotornaya 2Moscow 111116Russia

We present a semiempirical analytical model for the static polarizability of electronically excited atoms and molecules,which requires very few readily accessible input data,including the ground-state polarizability,elemental composition,ionization potential,and spin multiplicities of excited and ground *** very simple model formulated in a semiclassical framework is based on a number of observed trends in polarizability of electronically excited *** adjust the model,both accurate theoretical predictions and reliable measurements previously reported elsewhere for a broad range of multielectron species in the gas phase are *** some representative compounds of general concern that have not yet attracted sufficient research interest,the results of our multireference second-order perturbation theory calculations are additionally *** show that the model we developed has reasonable(given the considerable uncertainties in the reference data)accuracy in predicting the static polarizability of electronically excited species of arbitrary size and excitation *** findings can be useful for many applications,where there is a need for inexpensive and quick assessments of the static gas-phase polarizability of excited electronic states,in particular,when building the complex nonequilibrium kinetic models to describe the observed optical refractivity(dielectric permittivity)of nonthermal reacting gas flows.

关键词： polarizability electronic excitation semiempirical model quantum chemistry

Low-altitude geophysical magnetic prospecting based on multirotor UAv as a promising replacement for traditional ground survey

在线全文

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2018年第1期21卷 67-74页

作者： alexander v.Parshin vladimir A.Morozov Anton v.Blinov Alexey N.Kosterev alexander E.Budyak Ore Geology Lab Vinogradov Institute of Geochemistry SB RASIrkutskRussia SibGISTech LLC MarkovaRussia Geoinformatics Lab Irkutsk National Research Technical UniversityIrkutskRussia

The prospects for expanding the mineral resource base in many countries are linked with the exploration of stranded sites localized at unexplored areas with complex natural and landscape conditions that make any ground survey,including magnetic prospecting,difficult and *** current level of geology requires high-precision and large-scale data at the first stages of geological *** 2012,technologies of aeromagnetic surveying with unmanned aircraft vehicles(UAv)enter the market,but most of them are based on big fixed-wing UAv and do not allow to substantially increase the level of survey granularity compared with traditional aerial *** increase the scale of survey,it is necessary to reduce the altitude and speed of flight,for which the authors develop the methodical and technical solutions described in this *** obtain data at altitudes of 5 m above the terrain even in a rugged relief,we created heavy multirotor UAvs that are stable in flight and may be used in a wide range of environmental conditions(even a moderate snowfall),and develop a special software to generate flight missions on the basis of digital elevation models.A UAv has special design to reduce magnetic interference of the flight platform;the magnetic sensor is hung below the *** technology was conducted in a considerable amount of magnetic surveys in the mountainous regions of East Siberia between 2014 and *** results of the comparison between airborne and ground surveys are presented,which show that the sensitivity of the developed system in conjunction with low-altitude measurements can cover any geologically significant anomalies of the magnetic *** unmanned survey is cheaper and more productive;the multirotor-based technologies may largely replace traditional ground magnetic exploration in scales of 1:10,000−1:1000.

关键词： Unmanned aircraft vehicles(UAv) magnetic survey geophysical prospecting airborne geophysics unmanned aerial system(UAS)

A New Species of Aetheogrammatidae(Insecta:Neuroptera)with a Preserved Proboscis from the Lower Cretaceous of NE China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2020年第5期94卷 1714-1715页

作者： KHRAMOv alexander v. CHEN Jun Borissiak Paleontological Institute of Russian Academy of Sciences Profsoyuznayastr.123117997 MoscowRussian Federation Institute of Geology and Paleontology Linyi UniversityLinyiShandong 276000China

Objective The Aetheogrammatidae is a small family of extinct Neuroptera,which comprises six species in five genera,described from the Middle Jurassic to the Lower Cretaceous of China and *** are easily distinguishable... 详细信息

关键词： Cretaceous Jurassic Middle

Finding Symmetry Groups of Some Quadratic Programming Problems

在线全文

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2023年第2期16卷 370-392页

作者： Anton v.Eremeev alexander S.Yurkov Sobolev Institute of Mathematics SB RAS Omsk DepartmentOmskRussia Omsk Scientific Center SB RAS(Institute of Radiophysics and Physical Electronics) OmskRussia

Solution and analysis of mathematical programming problems may be simplified when these problems are symmetric under appropriate linear *** particular,a knowledge of the symmetries may help decrease the problem dimension,reduce the size of the search space by means of linear *** the previous studies of symmetries in the mathematical programming usually dealt with permutations of coordinates of the solutions space,the present paper considers a larger group of invertible linear *** study a special case of the quadratic programming problem,where the objective function and constraints are given by quadratic *** formulate conditions,which allow us to transform the original problem to a new system of coordinates,such that the symmetries may be sought only among orthogonal *** particular,these conditions are satisfied if the sum of all matrices of quadratic forms,involved in the constraints,is a positive definite *** describe the structure and some useful properties of the group of symmetries of the *** that,the methods of detection of such symmetries are outlined for different special cases as well as for the general case.

关键词： Non-convex programming orthogonal transformation symmetry group Lie group

Paleocene–early Eocene post-subduction magmatism in Sikhote-Alin (Far East Russia): New constraints for the tectonic history of the Izanagi-Pacific ridge and the East Asian continental margin

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2021年第4期12卷 71-85页

作者： Andrei v.Grebennikov Igor v.Kemkin alexander I.Khanchuk Far East Geological Institute Far Eastern BranchRussian Academy of Sciencespr.100-letiya Vladivostok 159Vladivostok 690022Russia Institute of Geology of Ore Deposits PetrographyMineralogy and Geochemistry(IGEM)Russian Academy of Sciences35 Staromonetny Per.Moscow 109017Russia

New isotopic,geochemical and geochronological data justify the widespread occurrence of middle Paleocene to early Eocene(60–53 Ma)post-subduction felsic magmatism across the entire Sikhote-Alin territory(southeastern Russia),conform with previous observations in Northeast China,the southern Korean Peninsula,and the Inner Zone of *** igneous activity in East Asia coincided with the reactivation(after tectonic quiescence between~93–60Ma)of left-lateral strike-slip displacements along the Tan-Lu and Central Sikhote-Alin faults and with the post-60 Ma cessation of subduction/accretion recorded in the Shimanto belt of SW *** Sikhote-Alin post-subduction igneous A-type rocks present diverse mineralogical and geochemical features that suggest interactions of the subducting plate with anhydrous mantle upwelling through slab tears in the continental *** middle Paleocene–early Eocene magmatismis not related to subduction but is synchronous with strikeslip tectonics and the termination of accretionary prism development,suggesting a shift in tectonic regime from oceanic plate subduction at a convergent margin to parallel sliding and initiation of a transformcontinental *** new observations are inconsistent with the current tectonic model of 60–50 Ma Izanagi-Pacific ridge subduction beneath East Asian continental margin.

关键词： Post-subduction magmatism Slab tear Sikhote-Alin Paleocene A-type rocks Izanagi-Pacific ridge

Mapping the spatial and temporal patterns of fallow land in mountainous regions of China

在线全文

学校读者我要写书评

暂无评论

International Journal of Digital Earth 2022年第1期15卷 2148-2167页

作者： Wen Song alexander v.Prishchepov Wei Song Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingPeople’s Republic of China School of Geomatics and Urban Spatial Informatics Beijing University of Civil Engineering and ArchitectureBeijingPeople’s Republic of China Department of Geosciences and Natural Resource Management (IGN) University of CopenhagenKøbenhavn KDenmark Department of Theoretical Cybernetics and Applied Mathematics Altai State UniversityBarnaulRussia

The rapid growth of the global population has resulted in a continuous increase in cropland intensity and a shortening of the fallow period as part of the cropland rotation ***,there is a lack of systematic knowledge on the extent of fallow lands,particularly in complex landscapes,such as the mountainous regions of *** fill this knowledge gap,taking Yuanyang County(YYC),Yunnan Province,China,as a case study,we tested a method to identify the spatial-temporal distribution of fallow land by mapping cropland with Landsat *** overall accuracy of land cover classification,including cropland,ranged between 90.1%and 95.8%from 1998 to *** average accuracy of fallow plots was 75.7%from 2001 to *** annual fallow rate varied between 8.3%and 54.3%,with an average of 20.7%.Kernel density estimated with the probability density function showed that fallow varied between 5 and 13 blocks per km2,gradually decreasing from the central area to the *** elevation,the low value of regional domestic products,and the increased distance to rural settlements were closely related to the higher proportions of fallow *** approach presented here can be applied to map fallow land in other regions.

关键词： Remote sensing fallow land kernel density time series China

Statistical Characteristics of the Received Signal for Stochastic Surface Models

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2002年第1期5卷 22-27页

作者： alexander v Ksendzuk Kharkov Aviation Institute

This paper describes the stochastic model of the scattered electromagnetic *** common_used functional_determined models the proposed is characterised by amplitude/phase fluctuation of the received *** paper derives the statistical characteristic of the input signal and describes algorithm for its estimation in post_processing and real_time processing *** characteristics allow the mapping and estimation of the surface models more accurate,moreover,such processing increase space resolution of synthetic aperture radar.

关键词： SAR surface model statistical characteristics estimation