检索结果-南通市图书馆

Functional traits of poplar leaves and fine roots responses to ozone pollution under soil nitrogen addition

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2022年第3期34卷 118-131页

作者： Pin Li Rongbin Yin Huimin Zhou sheng xu Zhaozhong Feng Research Center for Urban Forestry Key Laboratory for Forest Silviculture and Conservation of Ministry of EducationKey Laboratory for Silviculture and Forest Ecosystem Research in Arid-and Semi-arid Region of State Forestry AdministrationBeijing Forestry UniversityBeijing 100083China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Institute of Ecology Key Laboratory of Agrometeorology of Jiangsu ProvinceSchool of Applied MeteorologyNanjing University of Information Science and TechnologyNanjing 210044China

Concurrent ground-level ozone(O_(3))pollution and anthropogenic nitrogen(N)deposition can markedly influence dynamics and productivity in *** studies evaluating the functional traits responses of rapid-turnover organs to O_(3) have specifically examined leaves,despite fine roots are another major source of soil carbon and nutrient input in forest *** elevated O_(3) levels impact fine root biomass and biochemistry remains to be *** study was to assess poplar leaf and fine root biomass and biochemistry responses to five different levels of O_(3) pollution,while additionally examining whether four levels of soil N supplementation were sufficient to alter the impact of O_(3) on these two *** O_(3) resulted in a more substantial reduction in fine root biomass than leafbiomass;relative to leaves,more biochemically-resistant components were present within fine root litter,which contained high concentrations of lignin,condensed tannins,and elevated C:N and lignin:N ratios that were associated with slower rates of litter *** contrast,leaves contained more labile components,including nonstructural carbohydrates and N,as well as a higher N:P *** O_(3) significantly reduced labile components and increased biochemically-resistant components in leaves,whereas they had minimal impact on fine root *** suggests that O_(3) pollution has the potential to delay leaf litter decomposition and associated nutrient cycling.N addition largely failed to affect the impact of elevated O_(3) levels on leaves or fine root chemistry,suggesting that soil N supplementation is not a suitable approach to combating the impact of O_(3) pollution on key functional traits of *** results indicate that the significant differences in the responses of leaves and fine roots to O_(3) pollution will result in marked changes in the relative belowground roles of these two litter sources within forest ecosystems,and such chang

关键词： Ozone pollution Nitrogen(N)input Fine roots Leaves Functional traits Chemical complexity

Breaking the von Neumann bottleneck:architecture-level processing-in-memory technology

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2021年第6期64卷 60-69页

作者： Xingqi ZOU sheng xu Xiaoming CHEN Liang YAN Yinhe HAN Institute of Computing Technology Chinese Academy of Sciences Zhejiang Lab Department of Computer Technology and Information Anhui Normal University University of Chinese Academy of Sciences

The "memory wall" problem or so-called von Neumann bottleneck limits the efficiency of conventional computer architectures, which move data from memory to CPU for computation; these architectures cannot meet the demands of the emerging memory-intensive applications. Processing-in-memory(PIM) has been proposed as a promising solution to break the von Neumann bottleneck by minimizing data movement between memory hierarchies. This study focuses on prior art of architecture level DRAM PIM technologies and their implementation. The key challenges and mainstream solutions of PIM are summarized and introduced. The relative limitations of PIM simulation are discussed, as well as four conventional PIM ***, research directions and perspectives are proposed for future development.

关键词： processing-in-memory(PIM) von Neumann bottleneck memory wall PIM simulator architecture-level PIM

Development of An Ionospheric Scintillation Monitor Using Single Frequency GPS Receiver

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2002年第2期7卷 189-194页

作者： Shu Di-fei xu Ji-sheng School of Electronic Information Wuhan UniversityWuhan 430072HubeiChina

Besides their intended use in radio navigation, global positioning system (GPS) satellite signals provide convenient radio beacons for ionospheric studies. Among other propagation phenomena, the ionosphere affects GPS signal propagation through amplitude scintillations that develop after radio waves propagation through ionospheric electron density irregularities. This paper outlines the design, testing, and results of a specialized GPS receiver to monitorL-band scintillations. The scintillation monitor system consists of a commercial GPS receiver development kit with its software designed to log signal strength and carrier phase from up to 12 channels at one sample per second rate. Other prime features of the monitor include the data compression transmission and processing. Here is the fact that they are inexpensive and compact and therefore can be readily proliferated.

关键词： global positioning system ionosphere scintillation irregularity

Non-isothermal study of gasification process of coal char and biomass char in CO_2 condition

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2017年第10期24卷 985-990页

作者： Tao xu Guang-wei Wang Jian-liang Zhang Teng-fei Song Run-sheng xu School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Materials and Metallurgy Wuhan University of Science and Technology

Non-isothermal method was used to study gasification characteristics of three coal chars and one biomass *** chars were made from anthracite coal（A）,bituminous coal（B）,lignite coal（L）,and wood refuse（W）,*** gasification process was studied by random pore model（RPM）,unreacted core model（URCM）and volumetric model（VM）.With an increase in metamorphic grade,the gasification reactivity of coal char decreased,and the gasification reactivity of biomass char was close to that of low metamorphic coal *** an increase in heating rate,the gasification of all samples moved towards high temperature zone,and the whole gasification time *** was concluded from kinetics analysis that the above-mentioned three models could be used to describe the gasification process of coal char,and the RPM fitted the best among the three *** the RPM,the activation energies of gasification were193.9,225.3 and 202.8 kJ/mol for anthracite coal char,bituminous coal char and lignite coal char,*** gasification process of biomass char could be described by the URCM and VM,while the URCM performed *** activation energy of gasification of wood refuse char calculated by the URCM was 282.0 kJ/mol.

关键词： Coal char Biomass char Gasification Kinetic model

Enhancing Unsupervised Domain Adaptation for Person Re-Identification with the Minimal Transfer Cost Framework

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第9期80卷 4197-4218页

作者： sheng xu Shixiong Xiang Feiyu Meng Qiang Wu Research Institute of Electronic Science and Technology University of Electronic Science and Technology of ChinaChengdu610000China National Key Laboratory of Optical FieldManipulation Science and Technology Chinese Academy of SciencesChengdu610209China

In Unsupervised Domain Adaptation(UDA)for person re-identification(re-ID),the primary challenge is reducing the distribution discrepancy between the source and target *** can be achieved by implicitly or explicitly constructing an appropriate intermediate domain to enhance recognition capability on the target *** construction is difficult due to the absence of intermediate state supervision,making smooth knowledge transfer from the source to the target domain a *** explicitly construct the most suitable intermediate domain for the model to gradually adapt to the feature distribution changes from the source to the target domain,we propose the Minimal Transfer Cost Framework(MTCF).MTCF considers all scenarios of the intermediate domain during the transfer process,ensuring smoother and more efficient domain *** framework mainly includes threemodules:Intermediate Domain Generator(IDG),Cross-domain Feature Constraint Module(CFCM),and Residual Channel Space Module(RCSM).First,the IDG Module is introduced to generate all possible intermediate domains,ensuring a smooth transition of knowledge fromthe source to the target *** reduce the cross-domain feature distribution discrepancy,we propose the CFCM Module,which quantifies the difficulty of knowledge transfer and ensures the diversity of intermediate domain features and their semantic relevance,achieving alignment between the source and target domains by incorporating mutual information and maximum mean *** also design the RCSM,which utilizes attention mechanism to enhance the model’s focus on personnel features in low-resolution images,improving the accuracy and efficiency of person *** proposed method outperforms existing technologies in all common UDA re-ID tasks and improves the Mean Average Precision(mAP)by 2.3%in the Market to Duke task compared to the state-of-the-art(SOTA)methods.

关键词： Person re-identification unsupervised domain adaptation attention mechanism mutual information maximum mean discrepancy

Photo-assisted Deposited Titanium Dioxide Film and the Enhancement of Its Photocatalytic Water Splitting Activity

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

Chinese Journal of Structural Chemistry 2021年第9期40卷 1223-1230,1111页

作者： xu Chao-sheng LV Pei-Wen Fuzhou University College of Chemical EngineeringFuzhou 350116China Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Photo-assisted deposited method is often employed in the metal-organic chemical vapor deposition whose ion source is organic compounds. It has been proved to increase the deposition rate and improve the crystallinity of the films. We demonstrate a photo-assisted sputtering deposited method which is used to prepare high quality TiO_(2) films. The crystallinity of the films is improved by the photo assistance without changing the morphology. And the structural and optical properties remain the same. The photo-assisted deposited TiO_(2) film shows a H_(2) evolution rate of 1.62 μmol·cm^(-2)·h^(-1) that is about twice more than that of the pristine TiO_(2) film. It is found the Mott-Schottky effect responds for the photocatalytic activity. Photo-assisted deposited films show an enhanced photocatalytic activity due to the reduction of interface recombination and the high efficiency in the transferring of photo-generated carriers.

关键词： TiO_(2) photo-assisted Mott-Schottky photocatalyst

同方期刊数据库

Asymptotic Property of Approximation to x~αsgn x by Newman Type Operators

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2010年第4期26卷 617-624页

作者： Qian Zhan Shu-sheng xu Yue-hong Zhang Department of Mathematics Anhui University of Sciences and Technology Huainan 232001 China East China University of Sciences and Technology Shanghai 200237 China Yuanpei college Shaoxing University Shaoxing 312000 China

Approximation to the function ｜x｜ plays an important role in approximation theory. This paper studies the approximation to the function xαsgn x, which equals ｜x｜ if α = 1. We construct a Newman Type Operator rn... 详细信息

关键词： Rational approximation asymptotic property Newman type operator

Atomistic simulations of the surface severe plastic deformation-induced grain refinement in polycrystalline magnesium:The effect of processing parameters

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第5期10卷 1242-1255页

作者： Xiaoye Zhou Hui Fu Ji-Hua Zhu xu-sheng Yang Guangdong Province Key Laboratory of Durability for Marine Civil Engineering School of Civil EngineeringShenzhen UniversityShenzhenGuangdong 518060China State Key Laboratory of Ultra-precision Machining Technology Advanced Manufacturing Technology Research CentreDepartment of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Hong Kong Polytechnic University Shenzhen Research Institute ShenzhenChina

Magnesium(Mg)based alloys are promising candidates for many applications,but their untreated surfaces usually have low strength and *** this study,a single point diamond turning(SPDT)technique was applied to refine the grain size and improve the mechanical properties of the surface layers of Mg-Li *** refining grains in the topmost layer to the nanometer scale(~60 nm),the surface hardness was found to be enhanced by approximately 60%.The atomic plastic deformation process during the SPDT was then studied by the real-time atomistic molecular dynamics(MD)simulations.A series of MD simulations with different combinations of parameters,including rake angle,cutting speed and cutting depth,were conducted to understand their influences on the microstructural evolution and associated plastic deformation mechanisms on the surface layer of the *** MD simulation results suggest that using increased rake angle,cutting speed and cutting depth can help to achieve better grain *** simulation results,which provide atomic-level details of the deformation mechanism,can assist the parameter design for the SPDT techniques to achieve the high-performance heterogeneous nanostructured materials.

关键词： Mg alloy Grain refinement Surface severe plastic deformation MD simulations

Effects of Climate Warming on Phenological Characteristics of Urban Forest in Shenyang City,China

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2016年第1期26卷 1-9页

作者： HE Xingyuan xu sheng xu Wenduo CHEN Wei HUANG Yanqing WEN Hua State Key Laboratory of Forest and Soil Ecology Institute of Applied EcologyChinese Academy of Sciences Northeast Institute of Geography and Agroecology Chinese Academy of Sciences

Change in plant phenology is one of the most sensitive ecological responses to climate warming. Little information is known about the effects of climate warming on phenology of urban tree species in the northern forest of China. In this study, we investigated the phenological characteristics of the main tree species in the urban forest of shengyang City in China and the correlation between phenology and atmospheric temperature from the discontinuous data during past 42 years over three time periods(from 1962 to 1965, 1977 to 1978, and 2000 to 2005). The results showed that the annual average temperature in Shenyang City showed an increasing trend and increased by 0.96℃ from 1962 to 2005 due to climate warming. The germination phenology of the urban trees was negatively correlated with the temperature in winter and early spring. The leafing phenology was mainly influenced by the temperature in spring before leafing. Influenced by climate warming, the germination, leafing, and flowering phenologies of this urban forest in 2005 were 14, 13, and 10 days earlier than those in 1962, respectively. We inferred that further warming in winter might prolong the growing season of urban trees in the northern forest of China.

关键词： global climate change global warming plant phenology urban forest shengyang City