检索结果-南通市图书馆

Migration of organic carbon and trace elements in the system glacier-soil in the Central Caucasus alpine environment

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2022年第12期19卷 3458-3474页

作者： Ivan KUSHNOV evgeny ABAKUMOV Rustam TEMBOTOV Timur NIZAMUTDINOV Saint Petersburg State University 7/9 University EmbankmentSt Petersburg199034Russia Tembotov Institute of Ecology of Mountain Territories of Russian Academy of Sciences 7a I.Armand StreetNalchik360051Russia

Rapid deglaciation is one of the most important challenges in the Earth science *** reason of this is specific supraglacial sediments–cryoconites,which represent carbon-containing dust with organomineral matter and living *** of physical and chemical characteristics of cryoconites in the Central Caucasus is necessary in order to understand their influence on alpine territories biogeochemical cycles,pollution and development in conditions of intensive glacial melting and active anthropogenic *** this research cryoconites as well as moraines,soil-like bodies and soils have been sampled from the alpine Bezengi Glacier and adjacent Khulamo-Bezengi *** physicochemical features(pH values,total organic carbon content,microbial respiration,particle-size distribution)as well as content of trace elements have been defined in sampled materials and several pollution indices(Geoaccumulation index,Contamination factor and Degree of pollution)have been *** obtained show low values of total organic carbon in cryoconites(max.0.23%)but high values(max.7.54%)in top horizon of soils located in floodplain,indicating its active fluvioglacial transfer which may further accelerate the development of *** activity in the studied soils was mostly influenced by additional input of labile organic carbon from cryoconites with water ***-size distribution was similar among the studied cryoconites,indicating dominance of sand fraction(up to 85.28%)while studied soils showed higher variability due to influence of *** the trace elements,cryoconites were mostly polluted by Zn(max.85.70 mg·kg^(-1))which corresponds to high pollution according to pollution indices;Pb(max.24.90 mg·kg^(-1))and Cu(max.17.40 mg·kg^(-1)),up to moderate pollution *** of polluted cryoconite material as well as local anthropogenic activities increased pollution of periglacial soils by Zn(max.89.20 mg·kg^(-1)),Pb(m

关键词： Cryoconites Umbrisols Leptosols Pollution Caucasus mountain range

Features of the long-term transformation of the Krasnodar reservoir,near the mouth of the Kuban River,Russia

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2021年第12期31卷 1895-1904页

作者： POGORELOV Anatoly LAGUTA Andrey KISELEV evgeny LIPILIN Dmitry Kuban State University Krasnodar 350040Russia Aerogematica LLC Krasnodar 350063Russia Kuban State Agrarian University Named after I.T.Trubilin Krasnodar 350044Russia Tuapse Branch of the Russian State Hydrometeorological University Krasnodar RegionTuapse 352800Russia

The article considers the long-term(1941-2018)transformation of the Krasnodar valley reservoir,the largest in the North *** main functions of the Krasnodar reservoir are irrigation of rice systems and flood protection of land in the Krasnodar reservoir region and the Republic of *** to topographic maps,Landsat satellite images(1974-2018)and field observations(2016-2018),four stages of transformation of the floodplain reservoir are *** selected stages are characterized by both natural causes(the transformation of the filling deltas into the extended deltas,etc.)and man-made causes(runoff diversions in the delta areas,etc.).The key factor of transformation is the formation of deltas of rivers flowing into the *** of the selected stages,against the background of a gradual reduction in the area and volume of the reservoir,is characterized by the peculiarities of the formation of river deltas with the formation of genetically homogeneous sections of delta *** the period of operation of the reservoir,the delta of the main Kuban River moved up to 32.4 km and took away an area of 35.4 km^(2) of the *** the formation of the deltas of the Kuban and Belaya rivers,a bridge was formed on the Krasnodar *** evolution of the delta regions led to the division of the reservoir into two autonomous *** total area of the delta regions was 85.9 km^(2) by 2018,i.e.,21% of the initial area of the *** transformation of the Krasnodar reservoir leads to a decrease in its regulated volume and gradual degradation.

关键词： Krasnodar reservoir sedimentation siltation transformation delta formation Landsat

Sediments from cryoconite holes and dirt cones on the surface of Svalbard glaciers:main chemical and physicochemical properties

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2023年第2期42卷 346-359页

作者： Timur Nizamutdinov Bulat Mavlyudov Vyacheslav Polyakov evgeny Abakumov Department of Applied Ecology Faculty of BiologySt.Petersburg State University16th Liniya V.O.29St.PetersburgRussia 199178 Russian Academy of Sciences Institute of GeographyMoscowRussia 119017

The paper discussed the influence of the forms of sediment accumulation on the surface of glaciers on their chemical and physicochemical *** materials sampled from the surface of five glaciers of the Svalbard Archipelago was *** studied such forms of sediment accumulation as dirt cones-the ice core covered with sediments and cryoconite holes-hollows on the glacier surface containing cryoconite *** such as total organic carbon content,microbiological activity,pH,the content of mobile forms of potassium and phosphorus,and concentrations of heavy and trace metals were ***,mesomorphological studies were carried out and the polydisperse composition of the sediments was *** to the results of this work,it was found that the content of organic carbon in the material selected from dirt cones and cryoconite holes can be up to 2.5%,but the content of clay particles in it is mainly at the 10–15%*** concentrations are up to 250 mg/kg,and phosphorus is up to 800 mg/*** content of metals is typical or lower than in the previously published *** main influence on the chemical composition of materials has a geographical factor of the sampling site,rather than the form of material accumulation.

关键词： Arctic Soil-like bodies Glacier sediments Accumulation

Geochemistry of cryoconite and soils in the Central Caucasus region and its environmental implications

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2021年第12期18卷 3109-3124页

作者： Ivan KUSHNOV evgeny ABAKUMOV Rustam TEMBOTOV Vyacheslav POLYAKOV Saint Petersburg State University 7/9 University EmbankmentSt Petersburg 199034Russian Federation Tembotov Institute of Ecology of Mountain Territories Russian Academy of Sciences37-a I.Armand Str.Nalchik360051Russian Federation

Climate change and deglaciation are active processes in current changing *** the Central Caucasus region rapid degradation of glaciers is caused often by the formation of superficial blackcolored *** plays a crucial role in changing ecosystems and may contribute to the formation of primary soils after glacier *** the past 20 years,the frequency of mudflows and other dangerous mountain events have increased in the Central Caucasus,which is associated with the glacial *** of tourism results in increasing of traffic,recreational activity and environment *** of the cryoconites geochemical properties in comparison with other types of sediments and local soils is crucial for investigation of geochemistry and contamination state of superficial glacial *** environmental aspect is important in terms of the Central Caucasus settlements safety under conditions of deglaciation and anthropogenic *** sediments studied(cryoconite,mudflow,moraine)were sampled at Garabashi and Skhelda glaciers as well as some local soils at the Baksan *** materials were investigated in terms of physicochemical and agrochemical *** concentrations of trace elements(Cu,Pb,Zn,Ni,Cd)were also determined and contamination indices(geoaccumulation index-Igeo,contamination factor-CF and degree of contamination-Cdegree)were used to evaluate the pollution status of studied *** obtained shows much higher content of organic carbon in soils(up to 7.82%)in comparison with cryoconite(max.1.63%)due to presence of vegetation,however,the basal respiration values in some cases were similar betweenсryoconite and soils,indicating high rates of microbial activity in a cryoconite *** was found that almost all materials studied have sandy *** sediments on both of the glaciers are enriched with phosphorus,high values of K_(2)O(max.298 mg·kg^(-1))and N-NH4(max.

关键词： Cryoconite Trace elements Entisols Contamination Central Caucasus

Imaginary filtered hindsight experience replay for UAV tracking dynamic targets in large-scale unknown environments

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第5期36卷 377-391页

作者： Zijian HU Xiaoguang GAO Kaifang WAN Neretin evgeny Jinliang LI School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China School of Robotic and Intelligent Systems Moscow Aviation Institute(National Research University)Moscow 125993Russia Electromagnetic Space Operations and Applications Laboratory The 29th Research Institute of China Electronics Technology Group CorporationChengdu 610036China

As an advanced combat weapon,Unmanned Aerial Vehicles(UAVs)have been widely used in military *** this paper,we formulated the Autonomous Navigation Control(ANC)problem of UAVs as a Markov Decision Process(MDP)and proposed a novel Deep Reinforcement Learning(DRL)method to allow UAVs to perform dynamic target tracking tasks in large-scale unknown *** solve the problem of limited training experience,the proposed Imaginary Filtered Hindsight Experience Replay(IFHER)generates successful episodes by reasonably imagining the target trajectory in the failed episode to augment the *** welldesigned goal,episode,and quality filtering strategies ensure that only high-quality augmented experiences can be stored,while the sampling filtering strategy of IFHER ensures that these stored augmented experiences can be fully learned according to their high *** training in a complex environment constructed based on the parameters of a real UAV,the proposed IFHER algorithm improves the convergence speed by 28.99%and the convergence result by 11.57%compared to the state-of-the-art Twin Delayed Deep Deterministic Policy Gradient(TD3)*** testing experiments carried out in environments with different complexities demonstrate the strong robustness and generalization ability of the IFHER ***,the flight trajectory of the IFHER agent shows the superiority of the learned policy and the practical application value of the algorithm.

关键词： Artificial intelligence Autonomous navigation control Deep reinforcement learning Hindsight experience replay UAV

Countering DNS Amplification Attacks Based on Analysis of Outgoing Traffic

在线全文

学校读者我要写书评

暂无评论

Journal of Communications and Information Networks 2023年第2期8卷 111-121页

作者： evgeny Sagatov Samara Mayhoub Andrei Sukhov Prasad Calyam Sevastopol State University(SevSU) Universitetskaya ul.33Sevastopol 99026Russia Samara National Research University Moskovskoe sh.34Samara 443086Russia University of Missouri-Columbia 221 Naka HallColumbia MO 65211USA

Domain name system(DNS)amplification distributed denial of service(DDoS)attacks are one of the popular types of intrusions that involve accessing DNS servers on behalf of the *** this case,the size of the response is many times greater than the size of the request,in which the source of the request is substituted for the address of the *** paper presents an original method for countering DNS amplification DDoS *** novelty of our approach lies in the analysis of outgoing traffic from the victim’s *** servers used for amplification attacks are easily detected in Internet control message protocol(ICMP)packet headers(type 3,code 3)in outgoing *** packets of this type are generated when accessing closed user datagram protocol(UDP)ports of the victim,which are randomly assigned by the Saddam attack *** prevent such attacks,we used a Linux utility and a software-defined network(SDN)module that we previously developed to protect against port *** Linux utility showed the highest efficiency of 99.8%,i.e.,only two attack packets out of a thousand reached the victim server.

关键词： DNS amplification attacks outgoing traffic analysis port scanning attack network intrusion qualification attributes

Reversal of the magnetoelectric effect at a ferromagnetic metal/ferroelectric interface induced by metal oxidation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 1890-1896页

作者： Zhaojin Chen Qiong Yang Lingling Tao evgeny Y.Tsymbal School of Materials Science and Engineering Xiangtan UniversityXiangtanHunan 411105China Department of Physics and Astronomy University of NebraskaLincolnNE 68588USA

Multiferroic materials composed of ferromagnetic and ferroelectric components are interesting for technological applications due to sizable magnetoelectric coupling allowing the control of magnetic properties by electric *** to being compatible with the silicon-based technology,HfO2-based ferroelectrics could serve as a promising component in the composite ***,a strong charge-mediated magnetoelectric coupling has been predicted for a Ni/HfO_(2) multiferroic ***,using density functional theory calculations,we systematically study the effects of the interfacial oxygen stoichiometry relevant to experiments on the magnetoelectric effect at the Ni/HfO_(2) *** demonstrate that the magnetoelectric effect is very sensitive to the interface stoichiometry and is reversed if an oxidized Ni monolayer is formed at the *** reversal of the magnetoelectric effect is driven by a strong Ni−O bonding producing exchange-split polarization-sensitive antibonding states at the Fermi *** argue that the predicted reversal of the magnetoelectric effect is typical for other 3d ferromagnetic metals,such as Co and Fe,where the metal-oxide antibonding states have an opposite spin polarization compared to that in the pristine ferromagnetic *** results provide an important insight into the mechanism of the interfacial magnetoelectric coupling,which is essential for the physics and application of multiferroic heterostructures.

关键词： ferromagnetic ferroelectric bonding

Cumulation of a spherically converging shock wave in metals and its dependence on elastic-plastic properties, phase transitions, spall and shear fractures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Modeling, Simulation, and Scientific Computing 2015年第1期6卷 26-38页

作者： evgeny A.Kozlov Alexsander V.Petrovtsev Russian Federal Nuclear Center-Zababakhin Research Institute of Technical Physics Snezhinsk Chelyabinsk RegionRussia

Consideration is given to results of experimental and theoretical investigations how alpha-epsilon phase transition in the unalloyed iron and the 30 KhGSA steel and its absence in the austenitic 12Kh18N10T stainless steel influence processes under explosive deformation of spheres made of these *** transition is shown to significantly effect on:amount of explosion-products energy transferred to a sphere,evolution of the converging-wave structure and its parameters,profiles of stress wave and temperature T(R,t)for some Lagrangian particles along the sphere radius,character of energy cumulation under spherical convergence of waves.

关键词： Cumulation spherically converging shock wave elastic-plastic properties phase transitions spall and shear fractures

Percutaneous interventions in elderly patients with atrial fibrillation： leftatrial ablation and left atrial appendage occlusion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2017年第9期14卷 541-546页

作者： evgeny N Mikhaylov Tamas Szili-Torok Dmitry S Lebedev Arrhythmia Department Almazov National Medical Research Centre Saint-Petersburg Russia Neuromodulation Laboratory Almazov National Medical Research Centre Saint-Petersburg Russia Electrophysiology Unit Cardiology Department Erasmus Medical Center Rotterdam the Netherlands

Heart rhythm disturbances become of special importancewhen patients reach a senior age. Atrial fibrillation （AF） isthe most prevalent arrhythmia among the old age groups,and its impact on morbidity and mortality becomes of para-mount significance. In this population, AF is responsible forsignificant amount of thromboembolic cerebrovascularevents, especially for disabling and fatal strokes, Follow-ing announcement of the special issue of the Journal of Geri-atric Cardiology devoted to heart rhythm disorders in theelderly, a number of submissions have been received withAF as the major topic of authors＇ researches.

关键词： Atrial fibrillation Ablation Efficacy Left atrial appendage Occlusion Safety The elderly