检索结果-南通市图书馆

Site index for Chinese fir plantations varies with climatic and soil factors in southern China

Journal of Forestry Research 2022年第6期33卷 1765-1780页

作者： Xiaoyan Li Aiguo Duan Jianguo Zhang State Key Laboratory of Tree Genetics and Breeding Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland AdministrationResearch Institute of ForestryChinese Academy of ForestryBeijing 100091People’s Republic of China Collaborative Innovation Center of Sustainable Forestry in Southern China Nanjing Forestry UniversityNanjing 210037People’s Republic of China

Chinese fir[Cunninghamia lanceolata(Lamb.)Hook.]has a large native distribution range in southern China.Here,we tested differences in productivity of Chinese fir plantations in different climatic regions and screened the main environmental factors affecting site productivity in each region.Relationships of a Chinese fir site index with climatic factors and the soil physiochemical properties of five soil layers were examined in a long-term positioning observation trial comprising a total of 45 permanent plots in Fujian(eastern region in the middle subtropics),Guangxi(south subtropics)and Sichuan(central region in the middle subtropics)in southern China.linear mixed effects models were developed to predict the site index for Chinese fir,which was found to vary significantly among different climatic regions.Available P,total N,bulk density and total K were dominant predictors of site index in three climatic regions.The regional linear mixed models built using these predictors in the three climatic regions fit well(R~2=0.86–0.97).For the whole study area,the available P in the 0–20-cm soil layer and total N in the 80–100-cm soil layer were the most indicative soil factors.MAP was the most important climatic variable influencing the site index.The model evaluation results showed that the fitting performance and prediction accuracy of the global site index model using the climatic region as the dummy variable and random parameters and the most important soil factors of the three climatic regions as predictors was higher than that of global site index model using the climatic variable and the most indicative soil variables of the whole study area.Our results will help with further evaluation of site quality of Chinese fir plantations and the selection of its appropriate sites in southern China as the climatic changes.

关键词： Site productivity Site index Climate Soil Chinese fir

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

Levels and spatial distribution of heavy metals in urban dust in China

引用

Chinese Journal Of Geochemistry 2015年第4期34卷 498-506页

作者： Xiaoyan Li School of Geographic and Environmental Sciences Guizhou Normal University

Many studies have been conducted on heavy metal concentrations in urban outdoor dust in China,showing that differences exist in the metal concentrations of different cities. However, no report has studied the distribution of heavy metals across Chinese cities. This work presents the spatial distribution of heavy metals in urban outdoor dust in Chinese cities and discusses the causes for the differences in heavy metal levels across cities by analyzing and summarizing data for 20 provincial capitals from the published scientific literature. The results show that the geometric mean values of Ni and Cr in urban dust of China are lower than or comparable to crustal levels, whereas levels of Cd, Cu, Pb, and Zn are significantly greater than crustal levels. The spatial distributions of Cu, Pb, and Zn in urban dust all exhibit a pattern in which heavy metal levels are greater in cities located in the south of China than in the north. Commercial areas and residential-education areas accumulate more Cd in their dust than industrial areas and traffic areas, and industrial areas and residential-education areas accumulate more Pb than commercial areas and traffic areas. The Zn level in dust from industrial areas is significantly greater than in other areas, and Cu exhibits no significant difference between different functional areas. A positive correlation exists between Cd and Zn in urban dust and population density. Urban dust Pb in Chinese cities is lower than the world average as calculated using data for thirteen cities in different countries. Cd, Cu, and Zn levels in China are close to world averages.

关键词：空间分布特征重金属含量城市灰尘中国城市几何平均值空间分布格局教育领域交通领域

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

The Impact of a Public Health Emergency on the Demand for life Insurance-An Empirical Analysis Based on Severe Acute Respiratory Syndrome

引用

China & World Economy 2023年第3期31卷 230-266页

作者： Ying Sun Xiaoyan Li Yuantao Xie School of Insurance and Economics University of International Business and EconomicsChina

We examined changes in personal life insurance purchase decisions after a public health event by incorporating perceived health risk and regret into the expected utility function.The model predicts that the epidemic will create incremental insurance demand.Based on the 2003 severe acute respiratory syndrome outbreak in China,we used a panel dataset of 30 provinces from 2000 to 2007 and applied the difference-in-differences method to confirm the prediction empirically.The results showed that the epidemic did not significantly impact the demand for life insurance in the short term but played a role in the long term.People increased their health-care expenditure and premiums for new policies after the severe acute respiratory syndrome event,suggesting that the epidemic changed people's perceived risk and triggered anticipated regret,which increased life insurance demand.Some robustness checks also supported our findings.

关键词： health risk life insurance demand public health emergency regret theory

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

Fabrication of patterned transparent conductive glass via laser metal transfer for efficient electrical heating and antibacteria

引用

Nano Research 2024年第3期17卷 1578-1584页

作者： Xiaoyan Liu Ting Zhang Mengchen Xu Yang li Haiqing Wang Yuke Chen Xuzihan Zhang Zenan Wang Xiaoyan Li Weijia Zhou Hong liu Institute for Advanced Interdisciplinary Research(iAIR) School of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022China School of Physics and Technology University of JinanJinan 250024China Department of Endodontics School and Hospital of StomatologyCheeloo College of MedicineShandong University&Shandong Key Laboratory of Oral Tissue Regeneration&Shandong Engineering Laboratory for Dental Materials and Oral Tissue RegenerationJinan 250012China School of Information Science and Engineering University of JinanJinan 250022China Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China

Vapor deposition and three-dimensional(3D)printing technology are considered to be conventional methods to achieve patterned metal film preparation through the assistance of masks and high temperature.Therefore,there are still some challenges in fabricating metal films in template-free and normal temperature environment.In this work,we report a flexible and rapid laser metal transfer(LMT)technique for fabricating the various metal films(Cu,Ni,Sn,Al,Fe,and Ag)with different patterns without templates on arbitrary substrates(glass,polyimide(PI)films,and aluminum nitride(AlN)ceramic).Especially,the obtained transparent conductive glass displays high transmittance(more than 90%)and adjustable resistances(≈5Ω).According to the Joule effect,the interface resistance between Cu particles and copper oxide coating produces the high temperature approximately 280℃ at 2 V in a short time(≈60 s)and remains stable at 120℃ over 12 h.At last,the multifunctional glass with Cu patterns also shows excellent bactericidal activity(≈95%).This work demonstrates that laser metal transfer is an exceeding effective means of fabricating the micro/nano structures with potential applications in functional devices.

关键词： laser metal transfer(LMT) transparent conductive glass electrical heating copper pattern antibacterial

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

Citrate-promoted dissolution of nanostructured manganese oxides:Implications for nano-enabled sustainable agriculture

引用

Journal of Environmental Sciences 2023年第3期125卷 492-498页

作者： Di Fu lin Duan Xiaoyan Li Chuanjia Jiang Tong Zhang Wei Chen Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlCollege of Environmental Science and EngineeringNankai UniversityTianjin 300350China

Nanostructured manganese oxides (nano-MnO_(x)) have shown great promises as versatile agrochemicals in nano-enabled sustainable agriculture,owing to the coupled benefits of controlled release of dissolved Mn2+,an essential nutrient needed by plants,and oxidative destruction of environmental organic pollutants.Here,we show that three δ-MnO_(2)nanomaterials consisting of nanosheet-assembled flower-like nanospheres not only exhibit greater kinetics in citrate-promoted dissolution,but also are less prone to passivation,compared with three α-MnO_(2)nanowire materials.The better performance of the δ-MnO_(2)nanomaterials can be attributed to their higher abundance of surface unsaturated Mn atoms–particularly Mn(Ⅲ)–that is originated from their specific exposed facets and higher abundance of surface defects sites.Our results underline the great potential of modulating nanomaterial surface atomic configuration to improve their performance in sustainable agricultural applications.

关键词： Nano-enabled sustainable agriculture Nanostructured manganese oxides Controlled release Unsaturated Mn atoms Mn(III)

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

Production of the C/TiO_(2)composite with a high-performance electrochemical property from titanium-rich sludge via in-situ C coating

引用

Journal of Environmental Sciences 2024年第3期137卷 131-143页

作者： Hualong Wu Yanxia Zhao Jiexi Wang Xiaoyan Li Kaimin Shih Xuguang li Wei liu School of Water Conservancy and Environment University of JinanJinan 250022China State Key Lab of Physical Chemistry of Solid Surface Collaborative Innovation Center of Chemistry for Energy MaterialsCollege of MaterialsXiamen UniversityXiamen 361005China School of Metallurgy and Environment Central South UniversityChangsha 410083China Department of Civil Engineering The University of Hong KongPokfulamHong KongChina Institute of Environment and Ecology Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

Resource recycling from waste-water and sludge is an important part of the 14th Five-Year Plan in China.The emerging titanium-based coagulants have drawn growing attentions due to their strong coagulation capability in water purification and value-added Ti-loaded sludge production.Management and recovery of the high value-added sludge into functional nanomaterials is highly significant for both sludge reduction and environmental remediation.The present study was carried out to investigate the recycle of the coagulated Ti-loaded sludge to produce functional C/TiO_(2)composites as the anode materials for lithium-ion batteries(liBs).It is the first time that the application of the Ti-loaded wastewater sludge derived C/TiO_(2)was evaluated for liBs.The experimental results showed that the carbon coating through in-situ carbonization of the sludge produced the C/TiO_(2)composites with a high specific surface area,stable structural integrity,and excellent electrochemical properties that would facilitate li+diffusion in long-term liBs usage.The C/TiO_(2)composites calcinated from the polytitanium sulfate-coagulated sludge at 800℃(N_(2))exhibited the best electrochemical performance during the cycling tests(601 m Ah/g at 100 m A/g after 200 cycles).The research work demonstrates the promising prospect of the recycle and value-added utilization of the Ti-loaded sludge in the production of high-performance C/TiO_(2)composites for energy storage applications.This study provides a new way for the management and reuse of Ti-loaded waste-sludge.

关键词： Sludge recovery Ti-loaded sludge In-situ coating lithium-ion battery

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

Design optimization of a hexapod vibration isolation system for electro-optical payload

引用

Chinese Journal of Aeronautics 2024年第2期37卷 330-342页

作者： Jing li Weipeng li xiaoyan ZHANG Hai HUANG School of Astronautics Beihang UniversityBeijing 100191China

The electro-optical payloads on mobile platforms generally suffer undesirable vibrations generated by maneuvers and turbulence.These vibrations are in six degrees of freedom and cause line-of-sight jitters,resulting in image blurring and loss of tracking accuracy.In this paper,a Hexapod Vibration Isolation System(HVIS)is proposed and optimized to solve this problem.The optimization aims to centralize and minimize the natural frequencies of HVIS,for expanding the vibration isolation bandwidth and improving the vibration isolation in the higher frequency band.Considering that the design space for HVIS is limited and interfered with the frames of the mobile platform,a non-collision algorithm is proposed and applied in the optimization to obtain the feasible optimal design.The optimization result shows that the natural frequency bandwidth has been reduced by 42.9%,and the maximum natural frequency is reduced by 30.2%.The prototypes of initial and optimal designs are manufactured and tested.Both simulated and experimental results demonstrate the validity of the optimization,and the optimal design provides a maximum of 15 dB more isolation in rotation direction than the initial design.

关键词： Electro-optical payload Vibrations Isolation system Hexapod Optimization Non-collision design

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

Compound muscle action potential(CMAP)scan examination of paretic and contralateral muscles reveals motor unit alterations after stroke

引用

Science China(life Sciences) 2023年第11期66卷 2604-2613页

作者： Maoqi Chen Zhiyuan Lu Xiaoyan Li Ya Zong Qing Xie Sheng li Ping Zhou School of Rehabilitation Science and Engineering University of Health and Rehabilitation SciencesQingdao 266071China Department of Neurology Medical College of WisconsinMilwaukee WI 53226USA Fischell Department of Bioengineering University of Maryland at College ParkCollege Park MD 20742USA Department of Rehabilitation Medicine Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai 200025China Department of Physical Medicine and Rehabilitation University of Texas Health Science CenterHouston TX 77030USA TIRR Memorial Hermann Research Center TIRR Memorial Hermann HospitalHouston TX 77030USA

This study presents a novel compound muscle action potential(CMAP)examination of motor unit changes in paretic muscle post stroke.CMAP scan of the first dorsal interosseous(FDI)muscle was performed bilaterally in 16 chronic stroke subjects.Various parameters were derived from the CMAP scan to examine paretic muscle changes,including CMAP amplitude,D50,step index(STEPIX)and amplitude index(AMPIX).A significant decrease in CMAP amplitude and STEPIX was observed in paretic muscles compared with contralateral muscles(CMAP amplitude:paretic(9.0±0.5)mV,contralateral(11.3±0.9)mV,P=0.024;STEPIX:paretic 101.2±7.6,contralateral 121.9±6.5,P=0.020).No significant difference in D50 and AMPIX was observed between the paretic and contralateral sides(P>0.05).The findings revealed complex paretic muscle changes including motor unit degeneration,muscle fiber denervation,reinnervation and atrophy,providing useful insights to help understand neuromuscular mechanisms associated with weakness and other functional deterioration post stroke.The CMAP scan experimental protocols and the applied processing methods are noninvasive,convenient,and automated,offering practical benefits for clinical application.

关键词： compound muscle action potential(CMAP)scan stroke motor unit muscle weakness step index(STEPIX) first dorsal interosseous(FDI)

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

Changes and determining factors of crop evapotranspiration derived from satellite-based dual crop coefficients in North China Plain

引用

The Crop Journal 2022年第5期10卷 1496-1506页

作者： Qinghua Tan Yujie liu Tao Pan Xianfang Song Xiaoyan Li Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China

Evaluating actual crop evapotranspiration(ET) variations and their determining factors under changing climates is crucial for agricultural irrigation management and crop productivity improvement in nonhumid regions.This study analyzed the spatiotemporal characteristics and detected the determining factors of ETfor winter wheat and summer maize rotation system from 2000 to 2017 in the North China Plain(NCP),by combining the FAO-56 dual crop coefficient approach with remotely sensed vegetation indices(VIs).The results indicated that daily air temperature increased in varying degrees while wind speed and sunshine hours decreased slightly during the growing season of winter wheat and summer maize over the study period.The trends of relative humidity and effective precipitation varied in crop growing seasons.Based on the validated relationship of dual crop coefficients and VIs,the estimated multi-year average ETof winter wheat(370.29±31.28 mm) was much higher than summer maize(281.85±20.14 mm),and the rotation cycle was 652.43±27.67 mm.Annual ETof winter wheat and the rotation cycle increased by 2.96 mm aand 1,77 mm a,respectively.However,the ETof summer maize decreased with distinct spatial variation.Spatially,winter wheat ETincreased significantly in the northeast NCP,covering the Beijing-Tianiin-Hebei areas.Meanwhile,significant increases in summer maize ETwere detected in the southwest NCP.The sensitivity and contribution analysis showed that ETof winter wheat and summer maize was positively sensitive to temperature,wind speed,and sunshine hours while negatively to relative humidity.Moreover,wind speed and sunshine hours contributed most to changes in ET(around 20%-40%).

关键词： Actual crop evapotranspiration Determining factor North China Plain Rotation system Spatiotemporal variation

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

Anomalous strain effect on the thermal conductivity of low-buckled two-dimensional silicene

引用

National Science Review 2021年第9期8卷 23-31页

作者： Bin Ding Xiaoyan Li Wuxing Zhou Gang Zhang Huajian Gao Institute of High Performance Computing A*STAR Centre for Advanced Mechanics and Materials Applied Mechanics Laboratory Department of Engineering Mechanics Tsinghua University School of Materials Science and Engineering & Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion Hunan University of Science and Technology School of Mechanical and Aerospace Engineering College of Engineering Nanyang Technological University

The thermal conductivity of two-dimensional materials, such as graphene, typically decreases when tensile strain is applied, which softens their phonon modes. Here, we report an anomalous strain effect on the thermal conductivity of monolayer silicene, a representative low-buckled two-dimensional (LB-2D)material. Reax FF-based molecular dynamics simulations are performed to show that biaxially stretched monolayer silicene exhibits a remarkable increase in thermal conductivity, by as much as 10 times the freestanding value, with increasing applied strain in the range of [0, 0.1], which is attributed to increased contributions from long-wavelength phonons. A further increase in strain in the range of [0.11, 0.18] results in a plateau of the thermal conductivity in an oscillatory manner, governed by a unique dynamic bonding behavior under extreme loading. This anomalous effect reveals new physical insights into the thermal properties of LB-2D materials and may provide some guidelines for designing heat management and energy conversion devices based on such materials.

关键词： low-buckled two-dimensional materials strain effect thermal conductivity bonding dynamics

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

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：