检索结果-南通市图书馆

Nitrogen addition increased resistance of resident plant community to Solidago canadensis invasion by altering allelopathic effect

引用

Journal of Plant Ecology 2024年第2期17卷 110-121页

作者： Jing-Fang Cai Kai Sun lin li Si-ha.A Yi-Luan Shen Hong-li li School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China The Key Laboratory of EcologicalProtection in the Yellow River Basin of National Forestry and Grassland Administration Beijing Forestry UniversityBeijing 100083China

Allelopathy plays an important role in the interaction between invasive and resident *** nitrogen(N)deposition ha. become a global problem,but it is unclear whether N enrichment affects the interaction between invasive and resident plants by affecting their ***,we performed a greenhouse experiment in which the resident plant community was grown under two levels of invasion by ***(invasion *** invasion)and fully crossed with two levels of allelopathy(with or without adding activated carbon)and two levels of N addition(with or without).The resident plant communities were constructed with eight herbaceous species tha. often co-occur with *** results showed tha. both allelopathy of *** and the resident plants ha. obvious positive effects on their own *** addition ha. more obvious positive effects on the resident plants under invasion tha. those tha. were not ***,N addition also altered the allelopathy of resident ***,N addition improved the allelopathy of resident plants when they were invaded but decreased the allelopathy of resident plants when they grew *** nitrogen addition ha. no obvious effect on ***,it reduced the allelopathy of *** results suggest tha. N addition could improve the resistance of resident plants to invasion by improving the allelopathy of resident plants and reducing the allelopathy of *** fndings provide a scientifc basis to manage and control the *** invasion.

关键词： allelochemicals biological invasion nutrient input nitrogen addition resident plants Solidago canadensis

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

The Effect of Moisture in Different Altitude Layers on the Eastward Propagation of MJO

引用

Journal of Meteorological Research 2024年第3期38卷 437-452页

作者： Xiaoyu ZHU Zhong ZHONG Yimin ZHU Yunying li Yijia HU Yao ha College of Meteorology and Oceanography National University of Defense TechnologyChangsha410000China Key Laboratory for Virtual Geographic Environment School of Geography ScienceNanjing Normal UniversityNanjing210023China Jiangsu Collaborative Innovation Center for Climate Cha.ge School of Atmospheric SciencesNanjing UniversityNanjing210000China

In this study,driven by ERA5 reanalysis data,the Weather Research and Forecasting(WRF)version 4.0 was used to investigate the eastward propagation of the Madden-Julian oscillation(MJO)in the tropical atmosphere during December-February(DJF)of 2007/*** experiment with 11 cumulus parameterization schemes respectively shows tha. the Grell 3D scheme is one of several worse ones in describing MJO *** addition,still by use of the Grell 3D scheme,four nudging assimilation experiments for water vapor in all model vertical layers(Ndg_all),lower layers(Ndg_low),middle layers(Ndg_mid),and upper layers(Ndg_upp)were *** is found tha. when the water vapor in the model approaches to the observed value,the model performance for MJO activities is improved *** the four nudging simulations,Ndg_all certainly performs *** Ndg_mid is important for the MJO-filtered profiles related to moisture,Ndg_low and Ndg_upp exhibit superiority to Ndg_mid in simulating MJO eastward ***_low ha. advantages when MJO features are represented by zonal wind at 850 hPa and precipitation because the lower-level MJO-filtered moisture is conducive to the existence of lower-level condensational heating to the east of the MJO convective ***_upp performs better when describing the MJO eastward propagation features by outgoing longwave radiation(OLR)since it can capture the moisture and cloud top temperature of deep convection associated with MJO,as well as front Walker *** results suggest tha. the lower-level moisture is more important in regulating the MJO eastward propagation,and the observed maximum MJO-filtered moisture in the middle troposphere might be a phenomenon accompanying the MJO deep convection,but not a factor controlling its eastward propagation.

关键词： Madden-Julian oscillation(MJO) nudging technique Weather Research and Forecasting(WRF)model vertical moisture structure

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

Sandwich structures with tapered tubes as core:A quasi-static investigation

引用

Defence Technology（防务技术） 2024年第3期33卷 447-462页

作者： Xinmei Xiang Dehua Sha. Xin Zha.g Umer Sha.if Ngoc San ha.li Xiang Jing Zha.g Jiang Yi School of Civil Engineering Guangzhou UniversityGuangzhouChina Department of Mecha.ics and Aerospace Engineering Southern University of Science and TechnologyShenzhenGuangdongChina School of Engineering Centre for Innovative Structures and MaterialsRMIT UniversityMelbourneAustralia China Southern Airlines Co. LtdShenzhen BranchShenzhen518000China

In this article,the experimental and finite element analysis is utilized to investigate the quasi-static compression features of sandwich constructions built with tapered tubes.3D printing technology was utilized to create the hollow centers of the tapering tubes,with and without *** results demonstrate tha. the energy absorption(EA)and specific energy absorption(SEA)of the single corrugated tapered tube sandwich are 51.6% and 19.8% higher,respectively,tha. those of the conical tube ***,the results demonstrate tha. energy absorbers can benefit from corrugation in order to increase their ***,the tapered corrugated tubes'resistance to oblique impacts was *** to a straight tube,the tapered tube is more resistant to oblique loads and ha. a lower initial peak crushing force(PCF),according to numerical *** conducting a parametric study,it was discovered tha. the energy absorption performance of the sandwich construction is significantly affected by the amplitude,number of corrugations,and wall *** and SEA of DTS with corrugation number of 8 increased by 17.4%and 29.6%,respectively,while PCF decreased by 9.2% compared to DTS with corrugation number of 10.

关键词： Sandwich structure Corrugated tube Tapered tube Quasi-static Energy absorption

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

Visible light promoted aerobic selective photo-oxidation of cyclohexene on LaCo_(x)Cu_(1−x)O_(3) catalyst

引用

Nano Research 2024年第8期17卷 6940-6950页

作者： Xu Guo liru Song Wenyu Wang Fengfeng li Minh Ngoc ha.Jun Tang Qiang ling Ping Cui Qingping Ke College of Chemistry and Chemical Engineering Anhui University of TechnologyMaanshan 243000China VNU Key Laboratory of Advanced Material for Green Growth Faculty of ChemistryUniversity of ScienceVietnam National UniversityHanoi 100000Vietnam

Heterogeneously catalyzed liquid oxidation of olefins with O_(2) provides an alternative way for synthesizing high-value added ***,we report a straightforward urea-redox and sol-gel process for synthesizing LaCo_(x)Cu_(1−x)O_(3) for aerobic photooxidation of *** research highlights a marked increase in the proportions of Co^(2+) and Cu+species in a low chemical state,as well as enha.ced visible light absorption through this *** investigations suggest tha. the catalytic process,particularly with LaCo_(0.7)Cu_(0.3)O_(3),involves a radical pathway mediated by reactive oxygen *** presence of Cu+/Co^(2+) species and surface oxygen vacancies is proposed to boost O_(2) adsorption and activation on the catalyst,facilitating the formation of ***,Cu^(2+)/Co^(3+) species are thought to aid in generating cyclohexenederived radical *** efficient aerobic oxidation of cyclohexene on LaCo_(0.7)Cu_(0.3)O_(3) catalyst relies on the formation of reactive oxygen species and carbon radicals,facilitated by its strong visible light *** achieves a cyclohexene conversion of 89.4% and selectivity to cyclohex-2-ene-1-one of 72.2%,along with stable recyclability after six *** creation of nano-structured LaCo_(x)Cu_(1−x)O_(3) through the urea-redox and sol-gel process offers a promising avenue for the development of highly efficient catalysts for the aerobic photo-oxidation of cyclohexene to cyclohex-2-ene-1-one in the future.

关键词： perovskite oxide photocatalysis oxidation cyclohexene LaCoCuO_(3) cyclohex-2-ene-1-one

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

Towards the performance limit of catenary meta-optics via field-driven optimization

引用

Opto-Electronic Advances 2024年第5期7卷 33-42页

作者： Siran Chen Yingli ha.Fei Zha.g Mingbo Pu ha.lin Bao Mingfeng Xu Yinghui Guo Yue Shen Xiaoliang Ma Xiong li Xiangang Luo National Key Laboratory of Optical Field Manipulation Science and Technology Chinese Academy of SciencesChengdu 610209China State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering Institute of Optics and ElectronicsChinese Academy of SciencesChengdu 610209China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China Research Center on Vector Optical Fields Institute of Optics and ElectronicsChinese Academy of SciencesChengdu 610209China Department of Electrical and Computer Engineering University of California Los Angeles(UCLA)Los AngelesCalifornia 90095USA

Catenary optics enables metasurfaces with higher efficiency and wider bandwidth,and is highly anticipated in the imaging system,super-resolution lithography,and broadband ***,the periodic boundary approximation without considering aperiodic electromagnetic crosstalk poses cha.lenges for catenary optical devices to reach their performance ***,perfect control of both local geometric and propagation pha.es is realized through field-driven optimization,in which the field distribution is calculated under real boundary *** from other optimization methods requiring a mass of iterations,the proposed design method requires less tha. ten iterations to get the efficiency close to the optimal *** on the library of sha.e-optimized catenary structures,centimeter-scale devices can be designed in ten seconds,with the performance improved by ~15%.Furthermore,this method ha. the ability to extend catenary-like continuous structures to arbitrary polarization,including both linear and elliptical polarizations,which is difficult to achieve with traditional design *** provides a way for the development of catenary optics and serves as a potent tool for constructing high-performance optical devices.

关键词： catenary optics catenary structures field-driven optimization

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

PagMYB128 regulates secondary cell wall formation by direct activation of cell wall biosynthetic genes during wood formation in poplar

引用

Journal of Integrative Plant Biology 2024年第8期66卷 1658-1674页

作者： Yuanyuan ha. Fachuang Lu Seung-Won Pyo Min-ha.Kim Jae-Heung Ko Xiaojing Yan John Ralph Quanzi li State Key Laboratory of Tree Genetics and Breeding Chinese Academy of ForestryBeijing 100091China Department of Biochemistry and DOE Great Lakes Bioenergy Research Center Wisconsin Energy InstituteUniversity of Wisconsin-MadisonWisconsin 53726USA Department of Plant&Environmental New Resources Kyung Hee UniversityYongin 17104Korea

The biosynthesis of cellulose,lignin,and hemicelluloses in plant secondary cell walls(SCWs)is regulated by a hierarchical transcriptional regulatory *** network features orthologous transcription factors sha.ed between poplar and Arabidopsis,highlighting a foundational similarity in their genetic ***,knowledge on the discrepant beha.ior of the transcriptional-level molecular regulatory mecha.isms between poplar and Arabidopsis remains *** this study,we investigated the function of PagMYB128 during wood formation and found it ha. broader impacts on SCW formation compared to its Arabidopsis ortholog,*** poplar trees overexpressing PagMYB128 exhibited significantly enha.ced xylem development,with fiber cells and vessels displaying thicker walls,and an increase in the levels of cellulose,lignin,and hemicelluloses in the *** contrast,plants with dominant repression of PagMYB128 demonstrated the opposite *** sequencing and reverse transcription–quantitative polymerase cha.n reaction showed tha. PagMYB128 could activate SCW biosynthetic gene expression,and chromatin immunoprecipitation along with yeast one-hybrid,and effector–reporter assays showed this regulation was *** analysis revealed tha. PagSND1(SECONDARY WALL-ASSOCIATED NAC-DOMAIN PROTEIN1)directly regulates PagMYB128 but not cell wall metabolic genes,highlighting the pivotal role of PagMYB128 in the SND1-driven regulatory network for wood development,thereby creating a feedforward loop in SCW biosynthesis.

关键词： cellulose hemicellulose lignin PagMYB128 Populus transcription factor wood formation

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

中华民族共同体学话语体系的创新

引用

中南民族大学学报（人文社会科学版） 2024年第9期44卷 41-43页

作者：哈正利大连民族大学

2023年12月,国家民族事务委员会组织编写的《中华民族共同体概论》(以下简称《概论》)教材正式出版。该教材以习近平总书记关于加强和改进民族工作的重要思想为根本遵循。总体看来,《概论》教材成功建构了一个新的中华民族共同体叙事体... 详细信息

2023年12月,国家民族事务委员会组织编写的《中华民族共同体概论》(以下简称《概论》)教材正式出版。该教材以习近平总书记关于加强和改进民族工作的重要思想为根本遵循。总体看来,《概论》教材成功建构了一个新的中华民族共同体叙事体系和话语体系。中华民族史的研究肇始于近代中国。近代以来,陆续出版过一些中华民族史整体叙事的著作。

关键词：中华民族史《概论》中华民族共同体话语体系根本遵循教材习近平总书记叙事

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Semi-automated detection of rangeland runoff and erosion control berms using high-resolution topography data

引用

International Soil and Water Conservation Research 2024年第1期12卷 217-226页

作者： li li Cha.gjiang River Scientific Research Institute of Cha.gjiang Water Resources Commission Wuhan430010China Research Center on Mountain Torrent&Geologic Disaster Prevention Ministry of Water ResourcesWuhan430010China University of Arizona School of Natural Resources and the EnvironmentTucsonAZ85719USA

An inventory of topographic modifications is essential to addressing their impacts on hydrological and morphological processes in human-altered ***,such inventories are generally *** study presents two workflows for semi-automatic detection of linear earthen runoff and erosion control berms in rangelands using high-resolution topographic *** workflows consist of initial object identification by applying either morphological grayscale reconstruction(MGR)or the Geomorphon(GEO)method,followed by identification refinements through filters based on objects’horizontal and vertical *** sites were selected within the Altar Valley,Arizona,in the southwestern United *** site was used for developing workflows and optimizing filter thresholds,and the other two sites were used to validate *** results showed tha.:1)The MGR-based workflow methodology could produce final precision and detection rates of up to 92%and 75%,respectively,and take less tha. 5 s for a 10.1 km^(2) site;2)The workflow based on the MGR method yielded greater identification accuracy tha. did the GEO workflow;3)Object length,orientation,and eccentricity were important cha.acteristics for identifying earthen berms,and are sensitive to general cha.nel flow direction and berm sha.e;4)Manual interrogation of topographic data and imagery can significantly improve identification precision *** proposed workflows will be useful for developing inventories of runoff and erosion control structures in support of sustainable rangeland management.

关键词： Earthen berm Rangeland Grayscale morphological reconstruction Geomorphon liDAR

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

Perturbed low-thrust geostationary orbit transfer guidance via polynomial costate estimation

引用

Chinese Journal of Aeronautics 2024年第3期37卷 181-193页

作者： Zha. li Hengnian li Fanghua JIANG Junfeng li State Key Laboratory of Astronautic Dynamics Xi’an Satellite Control CenterXi’an 710043China School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary *** Earth’s oblateness perturbation and sha.ow are taken into *** is difficult for a Lyapunov-based or trajectory-tracking guidance method to possess multiple cha.acteristics at the same time,including high guidance optimality,robustness,and onboard computational *** this work,a concise relationship between the minimum-time transfer problem with orbital averaging and its optimal solution is identified,which reveals tha. the five averaged initial costates tha. dominate the optimal thrust direction can be approximately determined by only four initial modified equinoctial orbit elements after a coordinate *** on this relationship,the optimal averaged trajectories constituting the training dataset are randomly generated around a nominal averaged *** polynomial regression models are trained on the training dataset and are regarded as the costate *** the transfer,the spacecraft can obtain the real-time approximate optimal thrust direction by combining the costate estimations provided by the estimators with the current state at any ***,all these computations onboard are *** simulation results show tha. the proposed guidance scheme possesses extremely high guidance optimality,robustness,and onboard computational efficiency.

关键词： Low thrust Orbital transfer Trajectory optimization Guidance Indirect method Orbital averaging Machine learning Geostationary satellites

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

Theoretical Analysis of Cooperative Driving at Idealized Unsignalized Intersections

引用

Tsinghua Science and Technology 2024年第1期29卷 257-270页

作者： Shen li Jiawei Zha.g Zhenwu Chen li li Department of Civil Engineering Tsinghua UniversityBeijing 100084China Department of Automation Tsinghua UniversityBeijing 100084China Shenzhen Urban Transport Planning Center Co. Ltd.Shenzhen 518000China

Cooperative driving is widely viewed as a promising method to better utilize limited road resources and alleviate traffic *** recent years,several cooperative driving approaches for idealized traffic scenarios(i.e.,uniform vehicle arrivals,lengths,and speeds)ha.e been ***,theoretical analyses and comparisons of these approaches are *** this study,we propose a unified group-by-group zipper-style movement model to describe different approaches synthetically and evaluate their *** derive the maximum throughput for cooperative driving plans of idealized unsignalized intersections and discuss how to minimize the delay of *** obtained conclusions shed light on future cooperative driving studies.

关键词： cooperative driving connected and automated vehicles unsignalized intersection

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

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：