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International Journal of Digital Earth 2023年第1期16卷 3618-3636页

作者： Gorica Bratic vasil yordanov Maria Antonia Brovelli Politecnico di Milano MilanItaly

There has been a significant increase in the availability of global high-resolution land cover(HRLC)datasets due to growing demand and favorable technological advancements.However,this has brought forth the challenge of collecting reference data with a high level of detail for global extents.While photo-interpretation is considered optimal for collecting quality training data for global HRLC mapping,some producers of existing HRLCs use less trustworthy sources,such as existing land cover at a lower resolution,to reduce costs.This work proposes a methodology to extract the most accurate parts of existing HRLCs in response to the challenge of providing reliable reference data at a low cost.The methodology combines existing HRLCs by intersection,and the output represents a Map Of Land Cover Agreement(MOLCA)that can be utilized for selecting training samples.MOLCA’s effectiveness was demonstrated through HRLC map production in Africa,in which it generated 48,000 samples.The best classification test had an overall accuracy of 78%.This level of accuracy is comparable to or better than the accuracy of existing HRLCs obtained from more expensive sources of training data,such as photo-interpretation,highlighting the cost-effectiveness and reliability potential of the developed methodology in supporting global HRLC production.

关键词： High-resolution land cover global land cover training data reference data data quality

Olefin Polymerization Behavior of Titanium(IV) Complexes with Fluorinated and Non-fluorinated Aliphatic Phenoxyimine Ligands

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Chinese Journal of Polymer Science 2024年第1期42卷 52-62,I0007页

作者： Vladislav A.Tuskaev Kasim F.Magomedov Svetlana Ch.Gagieva Dmitry A.Kurmaev Yulia V.Nelyubina Evgenii K.Golubev Maria D.Evseeva Viktor G.vasil'ev Galina G.Nikiforova Mikhail I.Buzin Vyacheslav S.Bogdanov Boris M.Bulychev Department of Chemistry M.V.Lomonosov Moscow State UniversityMoscow 119992Russian Federation A.N.Nesmeyanov Institute of Organoelement Compounds Russian Academy of SciencesMoscow119991Russian Federation Enikolopov Institute of Synthetic Polymer Materials Russian Academy of SciencesMoscow 117393Russian Federation

A series of Ti(Ⅳ) dichloride and dialkoxide com plexes with phenoxyimine ligands containing fluorinated and nonfluorinated aliphatic imine fragments have been synthesized.The molecular structures of complexes 1 and 4 were established by single-crystal X-ray diffraction studies.The complexes adopt a distorted octahedral coordination structure around the titanium atom and two oxygen atoms are situated in trans position while two nitrogen atoms and two outgoing ligands(Cl or iPrO) are situated in cis position.Effect of activators(MMAO-12 and combinations Et_nAICl_(3-n)+Bu_(2)Mg) and outgoing ligand(Cl or iPrO) nature on the catalytic activity and properties of the resulting polymers was studied.The Ti complexes,despite the nature of the outgoing ligands(Cl or iPrO) in the presence of Al/Mg activators,was found to display a high ethylene polymerization activity in the range 1600-3830 kg_(polymer)·mol_(Ti)^(-1)·h^(-1)·atm^(-1) with a viscosity average molecular weight(M_v) value in the range 1.1×10~6-7.1×10~6 Dalton(Da).The resulting UHMWPE can be processed by a solventless method into high-strength and high-modulus oriented films.The rheological characteristics of a polymer melt have been studied.The absence of a cross-over point did not allow to compare the values of the molecular weight distribution of polymers obtained on fluorinated and non-fluorinated pre-catalysts,however,the estimation of the entanglement density is in good agreement with the mechanical characteristics of oriented film s.Upon activation with methylalumoxane,the activity of the com plexes decreased very significantly;however,a polymer with a molecular weight of about 12 million Da was obtained.In the process of ethylene/octene-1 copolymerization,fluorine-containing precatalysts showed a clear advantage over non-fluorinated analogues both in activity and in comonomer content.

关键词： FI catalysts Titanium(IV) (Co)polymerization Al/Mg co-catalyst Ultra-high molecular weight polyethylene

Effects of proteins on magnesium degradation-static vs.dynamic conditions

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Journal of Magnesium and Alloys 2023年第4期11卷 1332-1342页

作者： Ruiqing Hou Frank Feyerabend Heike Helmholz vasil M.Garamus Regine Willumeit-Römer School of Materials Science and Engineering&Henan Key Laboratory of Advanced Magnesium Alloys Zhengzhou UniversityNo.100 Science AvenueZhengzhou 450001China Institute of Metallic Biomaterials Helmholtz-Zentrum Hereon(Hereon)Max-Planck-Str.1Geesthacht 21502Germany

The interaction between organic molecules and biomaterial surfaces determines the fate of biomaterials during their service life,which is also the research hotspots in the field of biomaterials.To understand the mechanism of protein interaction with magnesium(Mg)degradation,alloying elements,immersion time,protein concentration and surface conditions have been previously considered for the effect of proteins on Mg degradation.However,fluid flow,as one of the critical factors,drew little attention in this case.In the present study,the effect of bovine serum albumin(BSA)and fetal bovine serum(FBS)on Mg degradation was compared under static and dynamic conditions.The results revealed that both BSA and FBS slightly decreased the degradation rate of Mg in Hanks’balanced salt solution(HBSS)under static immersion due to the protein adsorption and the formation of a Ca/P-rich top layer on Mg surface,whereas under dynamic flow condition the degradation of Mg was significantly accelerated in the presence of BSA or FBS.The reasons seemed to stem from the weakened protein adsorption on Mg surface in this case and the dynamically enhanced interaction between proteins and ions/products in solutions,which largely weaken the combination of the top Ca/P-rich layer with the inner corrosion product layer.These results highlight the importance of testing conditions for Mg characterization in vitro and the synergistic effect between different parameters on Mg degradation.

关键词： Flow Bovine serum albumin Fetal bovine serum Protein adsorption

Finite Groups Isospectral to Simple Groups

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Communications in Mathematics and Statistics 2023年第2期11卷 169-194页

作者： Maria A.Grechkoseeva Victor D.Mazurov Wujie Shi Andrey V.vasil’ev Nanying Yang Sobolev Institute of Mathematics Koptyuga 4NovosibirskRussia 630090 Department of Mathematics Chongqing University of Arts and SciencesChongqing 402160People’s Republic of China School of Mathematics Suzhou UniversitySuzhou 215006People’s Republic of China School of Science Hainan UniversityHaikou 570228HainanPeople’s Republic of China School of Science Jiangnan UniversityWuxi 214122People’s Republic of China

The spectrum of a finite group is the set of element orders of this group.The main goal of this paper is to survey results concerning recognition of finite simple groups by spectrum,in particular,to list all finite si... 详细信息

关键词： Finite group Simple group Element order Spectrum Recognition by spectrum

Sol-gel synthesis, surface and magnetic properties of nanocrystalline SmAlO_3

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Journal of Rare Earths 2010年第4期28卷 602-605页

作者： Dimitar Petrov Bogdan Angelov vasil Lovchinov Department of Inorganic and Physical Chemistry University of Food Technologies 26 Maritsa Blvd. 4002 Plovdiv Bulgaria Institute of Solid State Physics Bul garian Academy of Sciences 72Tzarigradsko Chaussee Blvd. 1784 Sofia Bulgaria

Nanocrystals of single-phase samarium monoaluminate (SmAlO3) were synthesized and studied for the first time. Malic acid was employed as a new complexing agent in the sol-gel process. The material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), specific surface area and density. The lowest size of the nanoparticles was about 50–60 nm and some of them formed agglomerates. The binding energies of core-level electrons of Sm (3d, 4d, 4f, ...

关键词： SmAlO3 nanocrystals surface properties magnetic susceptibility rare earths

Inhibition of the Ubiquitin-Proteasome Pathway Alters Cellular Levels of Nitric Oxide in Tomato Seedlings

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Molecular Plant 2010年第5期3卷 854-869页

作者： Sangeeta Negi Parankusam Santisree Eros vasil Kharshiing Rameshwar Sharma School of Life Sciences University of Hyderabad Hyderabad-500 046 India Present address: Donald Danforth Plant Science Centre 975 N. Warson Rd St Louis MO 63132 USA Present address: St Edmunds College Shillong Meghalaya India

Nitric oxide （NO） is involved in diverse plant growth processes; however, little is known about pathways regulating NO levels in plants. In this study, we isolated a NO-overproducing mutant of tomato （Solanum lycopersicurn） in which hyper-accumulation of NO, associated with increase in nitric oxide synthase （NOS）-Iike activity, caused diminished vegetative growth of plants and showed delayed flowering. The hyper-accumulation of NO caused drastic shortening of primary root （shr） in the seedlings, while the scavenging of NO restored root elongation in shr mutant. Inhibition of NOS- like activity reduced NO levels and stimulated root elongation in the shr mutant seedlings, while inhibition of nitrate reductase （NR） activity could not rescue shr phenotype. The stimulation of NO levels in shr mutant also conferred increased resistance to pathogen Pseudomonas syringae. Application of pharmacological inhibitors regulating ubiquitin-proteasome pathway reduced NO levels and NOS-like activity and stimulated shr root elongation. Our data indicate that a signaling pathway involving regulated protein degradation likely regulates NO synthesis in tomato.

关键词： Nitric oxide tomato nitric oxide synthase short root mutant plant development.

Early Holocene climate signals from stable isotope composition of ice wedges in the Chara Basin,northern Transbaikalia,Russia

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Geoscience Frontiers 2018年第2期9卷 471-483页

作者： Yurij K.vasil’chuk Alla C.vasil’chuk Julia V.Stanilovskaya Geography and Geology Departments Lomonosov Moscow State UniversityMoscowRussia Sergeev Environmental Geoscience Institute of the Russian Academy of Sciences Russia

Stable isotope composition of syngenetic and epigenetic ice wedges, radiocarbon age, and pollen spectra of the surrounding deposits were studied during long term investigations at the "Belyi Klyuch" site on the first(6-8 m height) terrace of the Chara River(720 m.a.s.l.) in northern Transbaikalia to assess climatic conditions during ice-wedge formation. It was revealed that Holocene ice wedges had been formed from 10 to 7.5 ka 14 C BP. The isotope composition(δ^(18)O, δ~2 H) of relict ice wedges is the lightest and amounts-23‰ and-185‰, correspondingly. The isotopic compositions of ice lenses from sandy loam above ice wedges are-15.7‰, and-133‰; of small ice wedge in peat and sand are-15.3‰ and-117.9‰, accordingly.Interpretation of the ice wedge isotope composition has yielded that mean winter temperatures during cold stages of Holocene optimum were lower than today, during warm stages they were close to modern ones. During the coldest stages of Holocene optimum the total annual freezing index varied from-5100 to-5700 ℃ degree days, i.e. 300-600 ℃ degree days colder than during extremely severe modern winters. The total annual thawing index varied from 1300 to 1800 ℃ degree days, which was slightly higher than modern ones.

关键词： Holocene Ice wedge Stable isotopes Southern permafrost areas Northern Transbaikalia

Boron Oxide Glasses and Nanocomposites: Synthetic, Structural and Statistical Approach

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Journal of Materials Science & Technology 2017年第6期33卷 535-540页

作者： Hristo Hristov Miroslava Nedyalkova Sergio Madurga vasil Simeonov Faculty of Chemistry and Pharmacy University of Sofia Physical Chemistry Department and Research Institute of Theoretical and Computational Chemistry (IQTCUB) of the University of Barcelona (UB)

Three different precursors of boron-aqua and glycerol solutions of boric acid and ethanol solution of trimethyl borate were used for the preparation of organic–inorganic advanced materials. The films and bulk materials samples were heat treated at 100, 400, 800？C for 2 h. The hybrid samples were stable and transparent until 100？C. The further increase of temperature to 400？C led to destruction of samples, and at 800？C they were molten. The structural changes during the pyrolysis were studied by Fourier transform infrared spectroscopy, differential thermal analysis, and X-ray diffraction. Details of surface morphology were observed by scanning electron microscopy. The obtained BO_3 and BO_4 groups were identified in the molten materials after pyrolysis. The quantities and order of borate structural units as well as residual carbon in the networks depended on boron precursor type. PVA/PEG/B_2O_3 hybrid materials were proved to be appropriate precursors for synthesizing borate and carboborate glass and carbon/borate glass nanocomposites. To access the impact of the experimental conditions on the structural changes of the nanocomposites, cluster analysis of the IR-spectral data was used as a classification method.

关键词： Organic–inorganic hybrid materials Borate glass Nanocomposites Cluster analysis

Geohelminths eggs contamination of sandpits in Vladivostok, Russia

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Asian Pacific Journal of Tropical Medicine 2016年第12期9卷 1190-1192页

作者： Moskvina Tatyana Vladimirovna Bartkova Albina Dmitrievna Ermolenko Alexey vasil'evich School of Natural Sciences Far Eastern Federal University Center of hygiene and epidemiology in Primorskii Region Institute of Biology and Soil Science Far-Eastern Branch of Russian Academy of Sciences

Objective: To detect nematode eggs in sandpits in urban area in Vladivostok. Methods: Totally 60 samples were collected from five districts. Sand samples were analyzed using combined flotation-sedimentation method. In result, 18 sand samples were positive for at one or two parasites species. Results: Overall, only 3 genera of helminths were recovered. Most samples were positive for Toxocara spp. eggs. Toxocara spp. eggs were found in each district. More samples with Toxocara spp. eggs were found in Pervomaiskii district. Ascaris spp. eggs were also appeared in each district, however Ascaris eggs rate of contamination was less than rate of Toxocara spp. contamination. Toxascaris leonina eggs were the less frequent species in sandpits, it was found only in Sovetskii and Pervomaiskii districts. Ascaris eggs rate of contamination was less than rate of Toxocara spp. contamination. Toxascaris leonina eggs were the less frequent species in sandpits, it was found only in two districts. No correlation between districts and helmiths eggs present in soil samples was found(P>0.05). Conclusions: Considering the high sand contamination with parasite infective elements of both human and animal origin, measures to improve environmental and sanitary conditions are indicated, as well as promoting the concept of responsible pet ownership.

关键词： Geohelminths Zoonosis Contamination Parasites

Pulse generation with ultra-superluminal pulse propagation in semiconductor heterostructures by superradiant-phase transition enhanced by transient coherent population gratings

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Light(Science & Applications) 2016年第1期5卷 737-743页

作者： Peter P vasil’ev Richard V Penty Ian H White Centre for Photonic Systems Department of EngineeringUniversity of CambridgeCambridge CB30FAUK Quantum Electronics Division PN Lebedev Physical InstituteMoscow 119991Russia

This paper reports the observation of ultra-superluminal pulse propagation in multiple-contact semiconductor heterostructures in a superradiant emission regime,and shows definitively that it is a different class of emission from conventional spontaneous or stimulated emission.Coherent population gratings induced in the semiconductor medium under strong electrical pumping have been shown to cause a major decrease of the group refractive index,in the range of 5–40%.This decrease is much greater than that caused by conventional carrier depletion or chirp mechanisms.The decrease in refractive index in turn causes faster-than-c propagation of femtosecond pulses.The measurement also proves the existence of coherent amplification of electromagnetic pulses in semiconductors at room temperature,the coherence being strongly enhanced by interactions of the light with coherent transient gratings locked to carrier gratings.This pulse-generation technique is anticipated to have great potential in applications where highly coherent femtosecond optical pulses must be generated on demand.

关键词： phase transition population grating superradiance superluminal propagation