检索结果-南通市图书馆

Floating plants reduced methane fluxes from wetlands by creating a habitat conducive to methane oxidation

Journal of Environmental Sciences 2024年第1期135卷 149-160页

作者： Fuwei Wang Songhe Zhang Xiuren Hu Xin Lv Min Liu Yu Ma Benjamin Manirakiza Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes Ministry of EducationHohai UniversityNanjing 210098China College of Environment Hohai UniversityNanjing 210098China China Machinery International Engineering Desigh and Research Institute co. Ltd.East China Regional CenterNanjing 210008China

Wetlands are one of the important natural sources of atmospheric methane (CH_4),as an important part of wetlands,floating plants can be expected to affect methane release.However,the effects of floating plants on methane release are limited.In this study,methane fluxes,physiochemical properties of the overlying water,methane oxidation potential and rhizospheric bacterial community were investigated in simulated wetlands with floating plants Eichhornia crassipes,Hydrocharis dubia,and Trapa natans.We found that E.crassipes,H.dubia,and T.natans plants could inhibit 84.31%-97.31%,4.98%-88.91%and 43.62%-92.51%of methane fluxes at interface of water-atmosphere compared to Control,respectively.Methane fluxes were negatively related to nutrients concentration in water column but positively related to the aerenchyma proportions of roots,stems,and leaves.At the same biomass,root of E.crassipes (36.44%) had the highest methane oxidation potential,followed by H.dubia (12.99%) and T.natans (11.23%).Forty-five bacterial phyla in total were identified on roots of three plants and 7 bacterial genera (2.10%-3.33%) were known methanotrophs.Type I methanotrophs accounted for 95.07%of total methanotrophs.The pmoA gene abundances ranged from 1.90×10^(16)to 2.30×10^(18)copies/g fresh weight of root biofilms.Abundances of pmoA gene was significantly positively correlated with environmental parameters.Methylotrophy (5.40%) and methanotrophy (3.75%) function were closely related to methane oxidation.This study highlights that floating plant restoration can purify water and promote carbon neutrality partially by reducing methane fluxes through methane oxidation in wetlands.

关键词： Floating plants Methane fluxes Aerenchyma Methanotrophs

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Bacterial succession in epiphytic biofilms and deciduous layer sediments during Hydrilla verticillata decay: A field investigation

引用

Journal of Environmental Sciences 2020年第7期32卷 193-201页

作者： Tingting Si Hezhou Chen Zheng Qiu Lisha zhang Okugbe Ebiotubo Ohore Songhe Zhang Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes College

Submersed macrophytes decay is an important natural process and has important role in mass and energy flow in aquatic ecosystems.However,little is known about the dynamical changes in nutrients release and bacterial community during submersed macrophyte decay in natural environment.In this study,a field observation was conducted in a wetland dominated with Hydrilla verticillata for 36 days.Increase of H2O2 and malondialdehyde(MDA)content and decrease of soluble proteins concentration were detected in leaves during H.verticillata decay.Meanwhile,ammonium-N,soluble microbial products(SMP)and TOC concentration increased in overlying water.According to bacterial 16 S r RNA Illumina sequencing analysis,the Shannon values were lower in epiphytic biofilms than deciduous layer sediments.The relative abundances of Proteobacteria,Cyanobacteria and Actinobacteria were higher in epiphytic biofilms than in deciduous layer sediments(P0.6)were identified from 122 and 112 genera in epiphytic biofilms and deciduous layer sediments,respectively.According to co-occurrence patterns,eight hubs were mainly from phyla Proteobacteria,Acidobacteria and Parcubacteria in epiphytic biofilms;while 37 hubs from the 14 phyla(Proteobacteria,Bacteroidetes,Acidobacteria,Chloroflexi,et al.)were detected in deciduous layer sediments.Our results indicate that bacterial community in deciduous layer sediments was more susceptible than in epiphytic biofilms during decay process.These data highlight the role of microbial community in deciduous layer sediments on nutrients removal during H.verticillata decay and will provide useful information for wetland management.

关键词： Submersed macrophyte Decay Biofilm Bacterial community Co-occurrence network

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

SOLVING NONLINEAR DELAY-DIFFERENTIAL-ALGEBRAIC EQUATIONS WITH SINGULAR PERTURBATION VIA BLOCK BOUNDARY VALUE METHODS

引用

Journal of Computational Mathematics 2023年第4期41卷 643-662页

作者： Xiaoqiang Yan Xu Qian Hong zhang songhe Song Xiujun Cheng College of Liberal Arts and Sciences National University of Defense TechnologyChangsha 410073China State Key Laboratory of High Performance computing National University of Defense TechnologyChangsha 410073China College of Science Zhejiang Sci-Tech UniversityHangzhou 310018China Institute of Natural Sciences Shanghai Jiao Tong UniversityShanghai 200240China

Block boundary value methods(BBVMs)are extended in this paper to obtain the numerical solutions of nonlinear delay-differential-algebraic equations with singular perturbation(DDAESP).It is proved that the extended BBVMs in some suitable conditions are globally stable and can obtain a unique exact solution of the DDAESP.Besides,whenever the classic Lipschitz conditions are satisfied,the extended BBVMs are preconsistent and pth order consistent.Moreover,through some numerical examples,the correctness of the theoretical results and computational validity of the extended BBVMs is further confirmed.

关键词： Nonlinear delay-diferential-algebraic equations with singular perturbation Block boundary value methods Unique solvability Convergence Global stability

来源：

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

Distribution and relationship between antimicrobial resistance genes and heavy metals in surface sediments of Taihu Lake,China

引用

Journal of Environmental Sciences 2019年第3期31卷 323-335页

作者： Okugbe E.Ohore Felix Gyawu Addo Songhe Zhang Nini Han Kwaku Anim-Larbi Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes College of Environment Hohai University

Heavy metals, pharmaceuticals, and other wastes released into the environment can significantly influence environmental antibiotic resistance. We investigated the occurrence of 22 antimicrobial resistance genes(ARGs) and 10 heavy metal concentrations, and the relationship between ARGs and heavy metals in surface sediment from seven sites of Lake Taihu. The results showed significant correlations(p < 0.05) between sediment ARG levels,especially for tetracycline and sulfonamides(e.g., tet(A), tet(D), tet(E), tet(O), sul1, sul2 and int-1) and specific heavy metals(Fe, Mn, Cr, Cu, Zn, among others) in the Lake. In the surface sediments, heavy metals showed an interaction with resistance genes, but the strength of interaction was diminished with increasing depth. For most of the heavy metals, the concentration of elements in the top sediments was higher than that in other depths.Tetracycline resistance genes(tet(A), tet(B), tet(D), tet(E) and tet(O), β-lactam resistance genes(SHV, TEM, CTX, OXA and OXY) and sulfonamide resistance genes(sulA, sul1, sul2, sul3 and int-1) were detected. They showed a trend which inferred a statistically significant increase followed by decreases in the relative abundance of these ARGs(normalized to 16 S rRNA genes) with increasing depth. This study revealed that tet(A), tet(O), TEM, OXY, int-1, sul1 and sul3 were widespread in surface sediments with high abundance, indicating that these genes deserve more attention in future work.

关键词： Antibiotic resistance genes Heavy metals Surface sediments Taihu Lake Wastewater treatment plants Pollution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental investigations on effects of gas pressure on mechanical behaviors and failure characteristic of coals

引用

Journal of Rock Mechanics and Geotechnical Engineering 2023年第2期15卷 412-428页

作者： Yi Xue P.G.Ranjith Feng Gao Zhizhen zhang songhe Wang State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an710048China Deep Earth Energy Laboratory Department of Civil EngineeringMonash UniversityBuilding 60MelbourneVictoria3800Australia State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221006China

The mechanical behavior of coal is the key factor affecting underground coal mining and coalbed methane extraction.In this study,triaxial compression and seepage tests were carried out on coal at different gas pressures.The mechanical properties and failure process of coal were studied,as well as the acoustic emission(AE)and strain energy.The influence of gas pressure on the mechanical parameters of this coal was analyzed.Based on the conventional energy calculation formula,the pore pressure was introduced through the effective stress formula,and each energy component of coal containing gas was refined innovatively.The contribution of gas pressure to the total energy input and dissipation during loading was quantitatively described.Finally,the influence of gas pressure on coal strength was theo-retically analyzed from the perspectives of MohreCoulomb criterion and fracture mechanics.The results show that the total absorbed energy comprises the absorbed energy in the axial pressure direction(positive)and in the confining pressure direction(negative),as well as that induced by the pore pressure(initially negative and then positive).The absorbed energy in the axial pressure direction accounts for the main proportion of the total energy absorbed by coal.The quiet period of AE in the initial stage shortens,and AE activity increases during the pre-peak stage under high gas pressure.The fractal characteristics of AE in three stages are studied using the correlation dimension.The AE process has different forms of self-similarity in various deformation stages.

关键词： Coal Gas pressure Acoustic emission(AE) Strain energy Fractal characteristics

来源：

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

A Maximum-Principle-Preserving Third Order Finite Volume SWENO Scheme on Unstructured Triangular Meshes

引用

Advances in Applied Mathematics and Mechanics 2018年第1期10卷 114-137页

作者： Yunrui Guo Lingyan Tang Hong zhang songhe Song Department of Mathematics and Systems Science and State Key Laboratory of High Performance ComputingNational University of Defense TechnologyChangshaHunan 410073China

We modify the construction of the third order finite volume WENO scheme on triangular meshes and present a simplified WENO(SWENO)scheme.The novelty of the SWENO scheme is the less complexity and lower computational cost when deciding the smoothest stencil through a simple mechanism.The LU decomposition with iterative refinement is adopted to implement ill-conditioned interpolation matrices and improves the stability of the SWENOscheme efficiently.Besides,a scaling technique is used to circument the growth of condition numbers as mesh refined.However,weak oscillations still appear when the SWENO scheme deals with complex low density equations.In order to guarantee the maximum-principle-preserving(MPP)property,we apply a scaling limiter to the reconstruction polynomial without the loss of accuracy.A novel procedure is designed to prove this property theoretically.Finally,numerical examples for one-and two-dimensional problems are presented to verify the good performance,maximum principle preserving,essentially non-oscillation and high resolution of the proposed scheme.

关键词： Triangular meshes WENO scaling limiter maximum-principle-preserving

来源：

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

High-order maximum-principle-preserving and positivity-preserving weighted compact nonlinear schemes for hyperbolic conservation laws

引用

Applied Mathematics and Mechanics(English Edition) 2020年第1期41卷 173-192页

作者： Lingyan TANG songhe SONG Hong zhang College of Liberal Arts and Sciences National University of Defense Technology

In this paper,the maximum-principle-preserving(MPP)and positivitypreserving(PP)flux limiting technique will be generalized to a class of high-order weighted compact nonlinear schemes(WCNSs)for scalar conservation laws and the compressible Euler systems in both one and two dimensions.The main idea of the present method is to rewrite the scheme in a conservative form,and then define the local limiting parameters via case-by-case discussion.Smooth test problems are presented to demonstrate that the proposed MPP/PP WCNSs incorporating a third-order Runge-Kutta method can attain the desired order of accuracy.Other test problems with strong shocks and high pressure and density ratios are also conducted to testify the performance of the schemes.

关键词： hyperbolic conservation law maximum-principle-preserving(MPP) positivity-preserving(PP) weighted compact nonlinear scheme(WCNS) finite difference scheme

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comparison of ablative and compressive mechanical behavior of several PICA-like ablative materials

引用

Science China(Technological Sciences) 2020年第8期63卷 1478-1486页

作者： zhang Jun FANG GuoDong YANG LingWei LI Wei HONG ChangQing MENG songhe National Key Laboratory of Science and Technology for Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang 621000China

It is significant to compare the ablative and compressive mechanical behavior of different PICA-like materials in the engineering applications.The plasma wind tunnel ablation tests with high-entropy air and CO2 atmospheres,and compressive experiments in the ambient and 150℃,were conducted for three kinds of PICA-like materials(CF/PR-Si,CBCF/PR-SiOC and NQF/PR-Si composites).The traditional carbon/phenolic(C/PR)braided composites were also used for comparison.PICA-like materials have the better thermal insulation than traditional C/PR composite,especially for CBCF/PR-SiOC composite.The ablation behavior of CF/PR-Si and CBCF/PR-SiOC PICA-like materials in the CO2 atmosphere can produce a large amount of SiO2 in the form of coatings,oxide layers and skeletons on the ablated surface,which are greatly different from that in the air atmosphere.The compressive behavior of PICA-like material is greatly depended on the fiber fabrics,and exhibits the large discrete characteristics.The longer fiber in the PICA-like materials plays the role in maintaining the material integrity,while it may increase the thermal conductivity.

关键词： PICA-like material ablation property plasma wind tunnel compressive behavior

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Splitting Method for the Degasperis-Procesi Equation Using an Optimized WENO Scheme and the Fourier Pseudospectral Method

引用

Advances in Applied Mathematics and Mechanics 2019年第1期11卷 53-71页

作者： Yunrui Guo Wenjing Yang Hong zhang Ji Wang songhe Song State Key Laboratory of High Performance Computing College of ComputerNational University of Defense TechnologyChangsha 410073China Department of Mathematics Utrecht UniversityThe Netherlands P.O.Box 80.0103508TAUtrecht Department of Mathematics College of SciencesNational University of Defense TechnologyChangsha 410073China

The Degasperis-Procesi(DP)equation is split into a system of a hyperbolic equation and an elliptic equation.For the hyperbolic equation,we use an optimized finite difference weighted essentially non-oscillatory(OWENO)scheme.New smoothness measurement is presented to approximate the typical shockpeakon structure in the solution to the DP equation,which evidently reduces the dissipation arising from discontinuities simultaneously removing nonphysical oscillations.For the elliptic equation,the Fourier pseudospectral method(FPM)is employed to discretize the high order derivative.Due to the combination of the WENO reconstruction and FPM,the splitting method shows an excellent performance in capturing the formation and propagation of shockpeakon solutions.The numerical simulations for different solutions of the DP equation are conducted to illustrate the high accuracy and capability of the method.

关键词： Degasperis-Procesi equation discontinuous solution weighted essentially nonoscillatory method pseudospectral method

来源：

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

Bioavailability of heavy metals in soil of the Tieguanyin tea garden, southeastern China

引用

Acta Geochimica 2017年第3期36卷 519-524页

作者： Jingwei Sun Ruilian Yu Gongren Hu songhe Jiang Yunfeng zhang Xiaoming Wang College of Chemical Engineering Huaqiao UniversityXiamen 361021 China School of Resources and Environmental Science Quanzhou Normal University Quanzhou 362000 China Analytical Laboratory of Beijing Research Institute of Uranium Geology Beijing 100029 China Fujian Provincial Key Laboratory of Ecology-Toxicological Effects and Control for Emerging Contaminants Putian China

The bioavailability of 22 heavy metals was investigated at 19 sampling sites in Tieguanyin tea garden in Anxi County,Fujian Province,southeastern China.Heavy metal concentrations were determined by inductively coupled plasma-mass spectrometry(ICP-MS)and evaluated by geo-accumulation index(I_(geo)).Dilute nitric acid extraction was used to evaluate biological activity.Cu,Pb,and Cd were highly bioavailable and most easily absorbed by tea trees.Heavy metal bioavailability in the surface soil was as the ratio of the effective state to the total amount.Cd had the highest I_(geo)values,and the respective samples and sites were classified as moderately/strongly contaminated.Cd element is considered the main factor of heavy metal pollution in the tea garden in Anxi.The other heavy metals studied were present in lower concentrations;thus,the samples were classified as uncontaminated or slightly contaminated.

关键词：生物有效性土壤重金属中国东南部铁观音电感耦合等离子体质谱法茶园重金属污染地质累积指数

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：