检索结果-南通市图书馆

Relative position of seeds driven the seedling growth are mediated by root-leaf traits

JOURNAL OF PLANT ECOLOGY 2024年第2期17卷 24-35页

作者： Zhu, jing Wang, Xue-Lin jin, Xing Jiang, Lan Lin, Hong-Yu Hu, Yang liu, jin-fu He, Zhong-Sheng fujian Agr & Forestry Univ Coll Forestry Fuzhou 350002 Peoples R China fujian Agr & Forestry Univ Key Lab Fujian Univ Ecol & Resource Stat Fuzhou 350002 Peoples R China Zhenjiang Nat Resources & Planning Bur Econ & Technol Dev Zone Branch Zhenjiang 212132 Peoples R China

Variations in plant traits are indicative of plant adaptations to forest environments, and studying their relationships with tree growth provides valuable insights into forest regeneration. The spatial arrangement of plant seeds within the forest litter or soil critically influences the variations of root-leaf traits, thereby affecting the adaptive strategies of emerging seedlings. However, our current understanding of the impacts of individual root-leaf traits on seedling growth in different relative position, and whether these traits together affect growth, remains limited. This study focuses on the dominant tree species, Castanopsis kawakamii, within the Sanming C. kawakamii Nature Reserve of China. The present experiment aimed to examine the variations in root-leaf traits of seedling, focus on the relative positions of seeds within different layers: beneath or above the litter layer, or within the bare soil layer (without litter). Our findings provided evidence supporting a coordinated relationship between root and leaf traits, wherein leaf traits varied in conjunction with root traits in the relative positions of seeds. Specifically, we observed that seedlings exhibited higher values for specific leaf area and average root diameter, while displaying lower root tissue density. The mixed model explained 86.1% of the variation in root-leaf traits, surpassing the variation explained by the relative positions. furthermore, soil nitrogen acted as a mediator, regulating the relationship between seedling growth and root-leaf traits, specifically leaf dry matter content and root tissue density. Therefore, future studies should consider artificially manipulating tree species diversity based on root-leaf traits characteristics to promote forest recovery.

关键词： relative growth rate coordination leaf traits root traits soil nitrogen content seed relative positions fuNCTIONAL TRAITS LIFE-HISTORY DISPERSAL MORTALITY DENSITY LITTER STEM

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

搅拌船用耐磨板YG20、Q355与TU1铜钎焊接头的性能分析

引用

船海工程 2024年第1期53卷 62-66页

作者：陈吉张笋刘进福张骞常州工业职业技术学院江苏常州213164 中车戚墅堰机车有限公司江苏常州213011 沪东中华造船集团有限公司上海200129

针对引进的国外某型搅拌船中的易损件中的耐磨板机械性能问题,选用硬质合金YG20与Q355低合金钢作为母材、TU1无氧铜作钎料进行真空钎焊,在不同的钎缝间隙下,进行焊接接头进行性能试验,对拉伸试样与冲击试样的断口形貌进行SEM扫描,结果表... 详细信息

针对引进的国外某型搅拌船中的易损件中的耐磨板机械性能问题,选用硬质合金YG20与Q355低合金钢作为母材、TU1无氧铜作钎料进行真空钎焊,在不同的钎缝间隙下,进行焊接接头进行性能试验,对拉伸试样与冲击试样的断口形貌进行SEM扫描,结果表明,YG20与Q355在TU1无氧铜作为钎料进行钎焊时,当钎缝间隙小于0.5 mm时能够获得很好的焊接接头;在0.4 mm时接头性能最佳,抗拉强度为439.8 MPa,达到母材抗拉强度上限值的69.8%;当钎缝间隙大于0.5 mm后,性能急剧下降;钎缝间隙在0.2 mm以下时,焊接接头断口呈脆性断裂,在0.3 mm以上塑性断裂现象随间隙值的增大而显现出一定的塑性。YG20和Q355通过铜钎焊能够获得良好的焊接接头;综合考虑钎焊批量生产的操作性、焊接接头性能等因素,推荐焊缝间隙范围为0.2~0.5 mm。

关键词：搅拌船耐磨板钎焊钎缝间隙接头性能

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 Numerical and Experimental Study on the Hull-Propeller Interaction of A Long Range Autonomous Underwater Vehicle

引用

China Ocean Engineering 2019年第5期33卷 573-582页

作者： WANG Ya-xing liu jin-fu liu Tie-jun JIANG Zhi-bin TANG Yuan-gui HUANG Cheng State key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang 110016 China Wuchang Shipbuilding Industry Group Co. Ltd. Wuhan 430060 China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang 110016 China

Range is an important factor to the design of autonomous underwater vehicles (AUVs), while drag reduction efforts are pursued, the investigation of body-propeller interaction is another vital consideration. We present a numerical and experimental study of the hull-propeller interaction for deeply submerged underwater vehicles, using a proportional-integral- derivative (PID) controller method to estimate self-propulsion point in CFD environment. The hydrodynamic performance of hull and propeller at the balance state when the AUV sails at a fixed depth is investigated, using steady RANS solver of Star-CCM+. The proposed steady RANS solver takes only hours to reach a reasonable solution. It is more time efficient than unsteady simulations which takes days or weeks, as well as huge consumption of computing resources. Explorer 1000, a long range AUV developed by Shenyang Institute of Automation, Chinese Academy of Sciences, was studied as an object, and self-propulsion point, thrust deduction, wake fraction and hull efficiency were analyzed by using the proposed RANS method. Behind-hull performance of the selected propeller MAU4-40, as well as the hull-propeller interaction, was obtained from the computed hydrodynamic forces. The numerical results are in good qualitative and quantitative agreement with the experimental results obtained in the Qiandao Lake of Zhejiang province, China.

关键词： underwater vehicle hydrodynamics hull-propeller interaction RANS simulation

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

Ecological Species Groups and Interspecific Association of Dominant Tree Species in Daiyun Mountain National Nature Reserve

引用

Journal of Mountain Science 2015年第3期12卷 637-646页

作者： SU Song-jin liu jin-fu HE Zhong-sheng ZHENG Shi-qun HONG Wei XU Dao-wei fujian Agriculture and Forestry University fujian Sanming Forest School Cross-Strait Nature Reserve Research Centre Fujian Agriculture and Forestry University

Abstract： Research on the ecological species groups and interspecific association of plant species are helpful to discover species coexistence processes and mechanisms, and to more fully understand plant community structure, function, and its taxonomy. However, little is known about the ecological species groups （ESG） and the interspecific association of dominant species in Daiyun Mountain National Nature Reserve of fujian Province, China. Therefore, the main goal of this paper is to explore the ESG using maximal tree, and to analyze interspecific associations of 32 dominant species selected from lo2 sample plots using the chi-square test. The results show that：（1） 32 dominant species have a significant overall positive interspecific association, which indicates that the natural forest in Daiyun Mountain National Nature Reserve is stable, （a） The species pairs with weak associations, non-associations and positive associations account for lo.88%, 29.64% and 59.48% of the total 496 species pairs respectively, which suggests that the population distributions of the dominant species investigated are relatively independent, （3） The following species pairs may be useful for practical application, 〈Pinus taiwanensis, Rhododendron farrerae〉, 〈Castanopsis carlesii, Altingia chinensis〉, 〈C. carlesii, Castanopsis fargesii〉, 〈Castanopsis eyrei, C. fargesii〉, 〈P. taiwanensis, Fagus lucida〉 , 〈Machilus thunbergii, Castanopsis nigrescens〉, and （4） The results of clustering analysis based on the maximal tree method indicates that the 32 dominant species can be divided into 3 ESGs when A at o.6o, that is ESG I {Pinus massoniana, Cunning hamia lanceolata}, ESG II {P. taiwanensis, R. farrerae, Enkianthus quinqueflorus}, ESG III {C. carlesii, A. chinensis, C. eyrei, Castanopsis fabri, C. fargesii, Schima superba, Machilus thunbergii, Rhododendron latoueheae}. The results may be used for the selection of afforestation tree species in South China Forest Areas and guide the natural manag

关键词： Ecological Species Groups InterspecificAssociation Daiyun Mountain National NatureReserve Maximal Tree

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

Leaf litter decomposition dynamics in unmanaged Phyllostachys pubescens stands at high elevations in the Daiyun Mountain National Nature Reserve

引用

Journal of Mountain Science 2017年第11期14卷 2246-2256页

作者： XU Dao-wei liu jin-fu Peter MARSHALL HE Zhong-sheng ZHENG Shi-qun Cross-strait Nature Reserve Research Center Fujian Agriculture and Forestry University Key Laboratory of fujian Universities for Ecology and Resource Statistics Faculty of Forestry University of British Columbia

Due to its rapid growth and high rate of spread, Phyllostachys pubescens can suppress other species, eventually leading to pure P. pubescens forests. Research on the patterns of litter decomposition and nutrient release from P. pubescens across stand mixtures are helpful to understand the decomposition and nutrient dynamics during the invasion process. However, little is known for unmanaged conditions at high elevations. Therefore, we studied the decomposition of four litter compositions comprised of different combinations of P. pubescens and Cunninghamia lanceolata foliage for one year to explore the pattern of litter decomposition and nutrient release at the Daiyun Mountain National Nature Reserve. The results show that:(1) the litter decomposed faster with a higher proportion of P. pubescens based on Olson's decay model;(2) the remaining litter compositions followed a trigonometric function model better than Olson'sdecay model and fluctuated periodically in tandem with changing temperature and precipitation;(3) the litter mixture decompositions did not support the biomass-ratio hypothesis test; and(4) there were significant binomial, power and exponential relationships between initial concentration and final amounts remaining after 1 year decomposition for C, N and P. The correlations between litter decomposition and nutrient releases were significant. The results may be used to explain the rapid spread of P. pubescens and to guide the natural management of plantations.

关键词： Decomposition models Biomass-ratiohypothesis Nutrient release pattern Phyllostachyspubescens Litter decomposition

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

双体负压爬壁机器人神经网络非奇异滑模控制

引用

制造业自动化 2024年第8期46卷 26-32,68页

作者：颜文俊徐林森孔令成刘进福常州大学微电子与控制工程学院江苏常州213164 河海大学机电工程学院江苏常州213022 中国科学院合肥物质科学研究院先进制造技术研究所江苏常州213164 常州工业职业技术学院江苏常州213164 常州市智能制造技术与装备重点实验室江苏常州213022

针对自主研制的双体负压滚动吸附式爬壁机器人控制中存在模型参数不确定和外部干扰等问题,设计了一种径向基神经网络(RBFNN)结合改进趋近律的准滑动模态控制的自适应轨迹跟踪控制方法。在对双体负压爬壁机器人建立动力学模型的基础上,采... 详细信息

针对自主研制的双体负压滚动吸附式爬壁机器人控制中存在模型参数不确定和外部干扰等问题,设计了一种径向基神经网络(RBFNN)结合改进趋近律的准滑动模态控制的自适应轨迹跟踪控制方法。在对双体负压爬壁机器人建立动力学模型的基础上,采用RBF神经网络逼近系统未知非线性动力学,消除外界未知干扰以及建模误差对系统的影响,实现了对双体负压爬壁机器人系统的精确控制。最后,将该控制方法应用于双体负压爬壁机器人进行实验验证,仿真结果和实验结果证明该方法在双体负压爬壁机器人轨迹跟踪中具有更快的收敛速度和削弱系统抖振的能力。

关键词：双体负压爬壁机器人径向基神经网络准滑动模态控制轨迹跟踪

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

Housing vacancy identification in shrinking cities based on multi-source data:A case study of fushun city in Northeast China

引用

Journal of Geographical Sciences 2024年第1期34卷 89-111页

作者： SUN Hongri ZHOU Guolei liu Yanjun fu Hui jin Yu School of Geographical Sciences Northeast Normal UniversityChangchun 130024China Northeast Institute of Geography and Agroecology CASChangchun 130102China

Urban shrinkage has attracted the attention of many geographers and urban planners in recent ***,there are fewer studies on vacant housing in shrinking ***,this study combines multi-source remote sensing images and urban building data to assess the spatiotemporal variation patterns of housing vacancy in a typical shrinking city in *** following points were obtained:(1)We developed an evaluation model to identify vacant residential buildings in shrinking cities by removing the contribution of nighttime lights from roads and non-residential buildings;(2)The residential building vacancy rate in fushun city significantly increased from 2013 to 2020,resulting in a significant high-value clustering *** impact of urban shrinkage on vacant residential buildings was higher than that on vacant non-residential buildings;(3)The World Pop population data demonstrated consistent spatial distribution and trend of population change in fushun with the residential building vacancy rate results,suggesting good reliability of the constructed evaluation model in this *** housing vacancies can help the local government to raise awareness of the housing vacancy problem in shrinking cities and to propose reasonable renewal strategies.

关键词： housing vacancy residential building vacancy urban shrinkage VIIRS

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

Large-scale toppling slope under water level fluctuation of reservoir:A case of Yunnan Province,China

引用

Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3034-3046页

作者： Leilei jin Yufeng Wei Fei Ye Wenxi fu Jianfeng liu Shuwu Li State Key Laboratory of Hydraulic and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China Northwest Engineering Corporation Limited Xi’an710065China

Landslides induced by reservoir inundation are common in Southwest China,negatively influencing hydropower *** hydropower station dam was constructed in the upper reaches of the Lancang River,accordingly causing the water level at the Lajinshengu slope to increase by 30 m.A tension crack with a visible depth of 8 m was observed in the upper sector of the Lajinshengu slope after reservoir impoundment for 170 *** the following days,numerous cracks appeared on the surface of the slope,and the maximum displacement of the slope reached 3.22 ***,a large-scale active deformation body within the Lajinshengu slope formed with an area of 2.62×10^(5)m^(2)and a volume of 1.65×10^(7)m^(3).Detailed field investigations,on-site monitoring,and centrifugal model tests were carried out to analyze the surface features,deformation characteristics,and failure mechanism of the Lajinshengu *** results show that the slope is an ancient landslide,divided into two parts(*** A and zone B)by the *** B is a traction landslide caused by the displacement of zone *** longterm inundation weakens the soft rock at the slope foot,intensifying the toppling of bedrock and consequently triggering the sliding of the overburden in zone *** failure mode of the Lajinshengu slope is a typical case of toppling-sliding failure,and the underlying rock toppling drives the overlying *** addition,early identification methods for toppling deformation covered by overburdened soil were proposed based on monitoring data and deformation signs.

关键词： Lajinshengu slope Reservoir impoundment Early identification Failure mechanism Toppling-sliding slope failure mode

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 expanded application of CAR-T cell therapy for the treatment of multiple non-tumoral diseases

引用

Protein & Cell 2024年第9期15卷 633-641页

作者： Zhuoqun liu Yuchen Xiao Jianjun Lyu Duohui jing liu liu Yanbin fu Wenxin Niu Lingjing jin Chao Zhang fundamental Research Center Shanghai Yangzhi Rehabilitation Hospital(Shanghai Sunshine Rehabilitation Center)School of MedicineTongji UniversityShanghai 201619China Hubei Topgene Research Institute of Hubei Topgene Biotechnology Co. Ltd.East Lake High-Tech Development ZoneWuhan 430205China Shanghai Institute of Hematology State Key Laboratory of Medical GenomicsNational Research Center for Translational Medicine at ShanghaiRuijin Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200025China Shanghai Yuhui Pharmaceutical Technology(Group)Co. Ltd.and Shanghai Ruishen Technology Development Co.Ltd.Shanghai 201203China Shanghai Cancer Institute Department of Biliary-Pancreatic SurgeryRenji Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200127China

As a powerful cell-based therapeutic approach,CAR-T therapy was originally designed for treating acquired immunodeficiency syndrome(AIDS)(Baker et al.,2023),but had been strikingly successful in curing hematologic malignancies and multiple solid *** evidence has expanded the medical application of CAR-T therapy for the treatment of many other human diseases beyond *** this article,we discuss the principle of CAR-T and enumerate the current application and limitation in ***,we provide a comprehensive perspective of current advance and future directions of CAR-T in treating multiple non-tumoral diseases.

关键词： diseases expanded treatment

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

Research advance of biomass and carbon storage of poplar in China

引用

Journal of Forestry Research 2006年第1期17卷 75-79页

作者： LIANG Wan-jun HU Hai-qing liu fu-jin ZHANG Da-ming Forestry College Northeast Forestry University Harbin 150040 Heilongfiang Province P. R. China Jilin Provincial Academy of Forestry Changchun 130033 Jilin Province P. R. China

This paper summarized the studies on biomass production, biomass growth models, biomass measurement, biomass and forest density, as well as carbon storage of poplars in China in recent 20 years. The existing problems ... 详细信息

关键词： Poplar Biomass Carbon Storage Review

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：