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Existence of two periodic solutions of a ratio-dependent Holling-Taner model with infinite delay and prey harvest

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Applied Mathematics(A Journal of Chinese Universities) 2008年第2期23卷 136-142页

作者： TIAN de-sheng College of Sciences Hubei University of Technology Wuhan 430068 China.

This paper considers a class of ratio-dependent Holling-Taner model with infinite delay and prey harvest, which is of periodic coefficients. By means of the coincidence degree theory, a set of sufficient conditions fo... 详细信息

关键词： Holling-Taner model ratio-dependent harvest periodic solution coincidence degree.

Floristics and Plant Biogeography in China

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Journal of Integrative Plant Biology 2008年第7期50卷 771-777页

作者： de-Zhu Li Key Laboratory of Biodiversity and Biogeography Kunming Institute of Botany the Chinese Academy of Sciences and Plant Germplasm and Genomics Center Germplasm Bank of Wild Species Kunming 650204 China

In 1998, a revolutionary system of angiosperm classification, the Angiosperm Phylogeny Group system was published. Meanwhile, another new system of classification of angiosperms, the eight-class system was proposed by C.Y. Wu and colleagues based on long term work on the flora of China. The Flora Reipublicae Popularis Sinicae project was initiated in 1959 and completed by 2004. It is the largest Flora so far completed in the world, including 31 228 species of vascular plants, or one-eighth of the global plant diversity. The English-language and updated Flora of China （FOC） is an international joint effort initiated in 1988 and accelerated in 1998. Up to now, 15 of the 24 volumes of the FOC have been published. Based on the floristic data, the composition, characteristics, floristic divisions and affinities of the flora of China have been studied by Wu and colleagues since 1965. In the past 10 years, analyses of the available floristic data have been very productive. The East Asiatic Floristic Kingdom was proposed in 1998. All 346 families of angiosperms in China, according to the eight-class system of classification, were comprehensively discussed by using knowledge of current and historical distribution of seed plants in the world, together with some morphological and molecular data. A scheme of distribution patterns or areal-types of families and genera of seed plants in China was modified and elucidated, together with a proposed scheme of areal-types of the world. Molecular phylogenetic and biogeographical studies of angiosperms in China in the past 10 years also witnessed a progressive development. Integration of morphological and molecular data and fossil evidence revealed some significant results. Eastern Asia, which used to be regarded as an important center of survival during the ice age, is likely an important center of diversification of angiosperms.

关键词： biogeography center of diversification eastern Asia floristics phylogenetics.

Zero-density Estimates for Automorphic L-functions

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Acta Mathematica Sinica,English Series 2009年第6期25卷 945-960页

作者： de Yu ZHANG School of Mathematical Sciences Shandong Normal University Ji'nan 250014 P. R. China

In this paper we prove zero-density estimates of the large sieve type for the automorphic L-function L（s, f × χ）, where f is a holomorphic cusp form and χ（mod q） is a primitive character.

关键词： cusp form L-function zero-density

Enantioselective reductive conjugate alkenylation of α,β-enones with keto alkenyl acetates by nickel catalysis

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Science China Chemistry 2025年第01期 157-162页

作者： Rong-de He Yun-Lei Luo Qiu-Quan Pan Qi-Wei Yao Xing-Zhong Shu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University

Reactions involving alkenyl acetates offer cost-effective and environmentally friendly routes for alkene synthesis, yet their asymmetric variant remains elusive. Concurrently, asymmetric conjugate alkenylation predominantly centered on nucleophilic addition using alkenyl–M. This manuscript presents an asymmetric reductive conjugate alkenylation reaction involving alkenyl acetates. The method facilitates the enantioselective addition of keto alkenyl groups to α,β-enones, resulting in the formation of unsaturated diketones—a class of useful structural motifs that are challenging to access otherwise. The use of electron-rich Pyroxy ligand is essential for achieving both high reaction efficiency and enantioselectivity.

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Focus on research advances in the natural gas hydrate resource evaluation: Introduction to papers in the special section of Evaluation of Natural Gas Hydrate Resource Potential in the South China Sea

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Petroleum Science 2022年第1期19卷 1-2页

作者： de-Li Gao Academician of Chinese Academy of Sciences Professor at China University of PetroleumBeijing 100083China

The continental hydrocarbon generation theory has opened a new field of oil and gas development and once solved the oil and gas shortage problem in *** then,geological theories of coalbed methane accumulation,foreland basin oil and gas accumulation,carbonate rock oil and gas accumulation,superimposed basin,and deep oil and gas accumulation have contributed to relieving the pressure of oil and gas shortage in China.

关键词： China. basin carbonate

Abiotic stress on seed germination and plant growth of Zeyheria tuberculosa

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Journal of Forestry Research 2023年第5期34卷 1511-1522页

作者： Robson Luis Silva de Medeiros Rinaldo Cesar de Paula Joao Vitor Oliveira de Souza Joao Pedro Peixoto Fernandes department of Agricultural Sciences School of Agricultural and Veterinarian SciencesSao Paulo State University(Unesp)14884-900JaboticabalSao PauloBrazil

Zeyheria tuberculosa(Vell.)Bureau ex *** among the Brazilian flora threatened with *** has high-quality wood and can be used to recover herbicidecontaminated ***,abiotic stresses can harm seed germination and seedling development under adverse conditions and need to be understood to improve autochthonous or indigenous biodiversity conservation and strengthen reforestation *** study evaluated the effects of temperature,water and saline stress on *** seed germination and water stress on seedling *** laboratory experiments evaluated germination under:(1)different temperatures(20,25,30,35 and 40℃);(2)different water potentials simulated with polyethylene glycol(PEG6000)at 25 and 30℃;and,(3)different osmotic potentials simulated with NaCl at 25 and 30℃.In addition,a greenhouse experiment subjected seedlings to five water regimes(20%,35%,50%,65%and 80%of maximum substrate water holding capacity).In the laboratory,seedling biometry and germination were evaluated,while physiological and morphological parameters were assessed in the *** potential of seeds increased at 25 and 30℃.Germination and vigor decreased as water and saline stresses *** tolerance thresholds for water and salt stresses were-0.6 and-0.4 MPa,*** the greenhouse,the most restrictive water regimes reduced seedling physiological and morphological *** development was compromised at moisture levels below50%field capacity.

关键词： Bignoniaceae Climate change Ipê-felpudo Ipê-preto Water stress

Fokker-Planck Type Equations with Sobolev Diffusion Coefficients and BV Drift Coefficients

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Acta Mathematica Sinica,English Series 2013年第2期29卷 303-314页

作者： de Jun LUO Institute of Applied Mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences

Combining Le Bris and Lions＇ arguments with Ambrosio＇s commutator estimate for BV vector fields, we prove in this paper the existence and uniqueness of solutions to the Fokker-Planck type equations with Sobolev diff... 详细信息

关键词： DiPerna-Lions theory Fokker-Planck equation stochastic differential equation BV reg-ularity commutator estimate

Coupling Alfvénic and Ion-Acoustic Solitons

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Chinese Physics Letters 1996年第8期13卷 594-597页

作者： WU de-jin WANG de-yu Carl-Gunne Fälthammar Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008*Department of Plasma PhysicsRoyal Institute of TechnologyStockholmSweden

An exact nonlinear equation governing the coupling Alfvénic and ion-acoustic solitons and criterion for their existence are *** the case of low-β plasmas,the two modes *** the small amplitude limit,the analytical re... 详细信息

关键词： solitons exact criterion

Duration and intensity of rainfall events with the same erosivity change sediment yield and runoff rates

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International Soil and Water Conservation Research 2021年第1期9卷 69-75页

作者： Wilk Sampaio de Almeida Steffen Seitz Luiz Fernando Coutinho de Oliveira Daniel Fonseca de Carvalho Agronomy department Federal Institute of EducationScience and Technology of RondôniaCampus AriquemesRO 257km 13AriquemesRO76870-000Brazil department of Geosciences University of TübingenTübingenGermany Federal University of Lavras Department of Water Resources and Sanitation37200-000LavrasMGBrazil Federal Rural University of Rio de Janeiro Engineering DepartmentBR 465km 723897-000SeropédicaRJBrazil

The effect of different rainfall patterns on surface runoff,infiltration and thus soil losses and sediment concentrations are still in the focus of current *** most simulated rainfall experiments,pre-cipitation is applied at a fixed intensity for a fixed ***,the impact of rainfall patterns on soil erosion processes may be different varying the rainfall duration and intensity that produces an event with similar rainfall erosivity ***-five rainfall events were applied on micro-scale runoff plots in a soil covered with corn straw to evaluate the sediment yield and runoff *** different rainfall types were composed by association of duration(Dur)and intensity(IP)with the same erosivity *** Dur varied from 38 to 106 min and the IP varied from 75.0 to 44.6 mm h^(-1).The sediment yield varied from 1.89±1.26 g m^(-2) to 4.02±2.66 g m^(-2) and runoff ranged from 16.9±8.74 mm to 32.63±10.67 mm with highest rates occurring with high intensity and low *** highest rainfall intensity provides the maximum sediment yield(0.138 g m^(-2) min^(-1))and runoff rates(0.87 mm min^(-1)).The time to start surface runoff varied from 14 to 19.2 min and it was longer in treatments with longer durations and low precipitation *** difference was found in the amount of sediments applying rain with the same erosivity and different associations of duration and ***,the intensity and duration of the rain,with the same erosivity,altered the amount and time of *** rainfall experiments with con-stant intensity and fixed time,the erosion rates depend on the duration of the applied ***,the results of this study can contribute to the development of new perspectives in the design of water erosion experiments with simulated rain considering the duration,intensity and also the association of these variables to produce rainfall that delivery the same soil erosion capacity.

关键词： Simulated rainfall Rainfall pattern Water erosion Soil loss