检索结果-南通市图书馆

物理实验 2001年第11期21卷 38-39页

作者：翟林华征洋姚关心金伟张洪涛方涛安徽师范大学物理与信息工程学院安徽芜湖241000

讨论了普通物理光学实验有关教材中单色仪定标实验中定标所依据的汞光谱谱线标定问题 ,通过实验确定了实验可以明显观察到而未能标定的谱线。

关键词：单色仪定标汞光谱谱线标定物理教学光学实验高校

Bi-/multi-modal pore formation of PLGA/hydroxyapatite composite scaffolds by heterogeneous nucleation in supercritical CO_2 foaming

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第1期26卷 207-212页

作者： xin xin Yixin guan Shanjing Yao College of Chemical and Biological Engineering Zhejiang University

Scaffolds with multimodal pore structure are essential to cells differentiation and proliferation in bone tissue engineering. Bi-/multi-modal porous PLGA/hydroxyapatite composite scaffolds were prepared by supercritical C02 foaming in which hydroxyapatite acted as heterogeneous nucleation agent. Bimodal porous scaffolds were prepared under certain conditions, i.e. hydroxyapatite addition of 5%, depressurization rate of 0.3 MPa. min-1, soaking temperature of 55 ℃, and pressure of 9 MPa. And scaffolds presented specific structure of small pores （122 μM ± 66 μm） in the cellular walls of large pores （552 μm ±127 μm）. Furthermore, multimodal porous PLGA scaffolds with micro-pores （37 μM ± 11μM） were obtained at low soaking pressure of 7.5 MPa. The interconnected porosity of scaffolds ranged from （52.53 ± 2.69）% to （83.08±2.42）% by adjusting depressurization rate, while compression modulus satisfied the requirement of bone tissue engineering. Solvent-free CO2 foaming method is promising to fabricate bi-/multi-modal porous scaffolds in one step, and bioactive particles for osteogenesis could serve as nucleation agents.

关键词： Supercritical carbon dioxide Foam Tissue engineering PLGA scaffolds Hydroxyapatite Bi-/multi-modal pore

The evolution of coarse grains and its effects on weakened basal texture during annealing of a cold-rolled magnesium AZ31B alloy

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 1235-1241页

作者： xin Wang Dikai guan Department of Materials Science and Engineering University of SheffieldSheffield S13JDUK

The nucleation,grain growth of 34 coarse grains during annealing were tracked using a quasi-in-situ EBSD *** 34 coarse grains had different orientations and most grains were non-basal *** preferable grain growth or special types of grain boundaries were *** 9 coarse grains nucleated from deformed grain boundaries due to initial large grain size and limited grain boundary volume *** main nucleation site of 34 coarse grains was dislocation cells or subgrains in deformed grain *** recrystallisation behaviour can be illustrated by abnormal subgrain growth(As GG)rarely reported in Mg *** coarse basal grains showed no growth advantage in terms of grain size or number over other non-basal grains,leading to a weak basal texture in AZ31B alloy.

关键词： Magnesium alloy EBSD Annealing Recrystallisation Grain growth

A Field Study on Effects of Nitrogen Fertilization Modes on Nutrient Uptake,Crop Yield and Soil Biological Properties in Rice-Wheat Rotation System

在线全文

学校读者我要写书评

暂无评论

Agricultural Sciences in China 2011年第8期10卷 1254-1261页

作者： guan guan TU Shu-xin YANG Jun-cheng zhang Jian-feng YANG Li College of Resource and Environment Huazhong Agricultural UniversityWuhan 430070P.R.China Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural SciencesBeijing 100081P.R.China Institute of Plant Protection and Soil Fertilizer Hubei Academy of Agricultural SciencesWuhan 430064P.R.China

Rational application of nitrogen （N） fertilizers is an important measure to raise N fertilizer recovery rate and reduce N loss.A two-year field experiment of rice-wheat rotation was employed to study the effects of N fertilization modes including a N fertilizer reduction and an organic manure replacement on crop yield,nutrient uptake,soil enzyme activity,and number of microbes as well as diversity of *** result showed that 20% reduction of traditional N fertilizer dose of local farmers did not significantly change crop yield,N uptake,soil enzyme activity,and the number of microbes （bacteria,actinomycetes,and fungi）.On the basis of 20% reduction of N fertilizer,50% replacement of N fertilizer by organic manure increased the activity of sucrose,protease,urease,and phosphatase by 46-62,27-89,33-46,and 35-74%,respectively,and the number of microbes,i.e.,bacteria,actinomycetes,and fungi by 36-150,11-153,and 43-56%,***,organic fertilizer replacement had a Shannon＇s diversity index （H） of 2.18,which was higher than that of other modes of single N fertilizer *** results suggested that reducing N fertilizer by 20% and applying organic manure in the experimental areas could effectively lower the production costs and significantly improve soil fertility and biological properties.

关键词： rice-wheat rotation N fertilization mode organic manure replacement soil enzyme activity microbial diversity

Label distribution learning for scene text detection

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2023年第6期17卷 5-12页

作者： Haoyu MA Ningning LU Junjun MEI Tao guan Yu zhang xin GENG School of Computer Science and Engineering and the Key Lab of Computer Network and Information Integration(Ministry of Education)Southeast UniversityNanjing 211189China ZTE Corporation Nanjing 210012China

Recently,segmentation-based scene text detection has drawn a wide research interest due to its flexibility in describing scene text instance of arbitrary shapes such as curved ***,existing methods usually need complex post-processing stages to process ambiguous labels,i.e.,the labels of the pixels near the text boundary,which may belong to the text or *** this paper,we present a framework for segmentation-based scene text detection by learning from ambiguous *** use the label distribution learning method to process the label ambiguity of text annotation,which achieves a good performance without using additional post-processing *** on benchmark datasets demonstrate that our method produces better results than state-of-the-art methods for segmentation-based scene text detection.

关键词： scene text detection multi-task learning label distribution learning

Sensor/Actuator Faults Detection for Networked Control Systems via Predictive Control

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2013年第3期10卷 173-180页

作者： Yu-Yan zhang Jun-Ling zhang Xiao-Yuan Luo xin-Ping guan Institute of Electrical Engineering Yanshan University

Quantized fault detection for sensor/actuator faults of networked control systems （NCSs） with time delays both in the sensor-to-controller channel and controller-to-actuator channel is concerned in this paper. A fault model is set up based on the possible cases of sensor/atuator faults. Then, the model predictive control is used to compensate the time delay. When the sensors and actuators are healthy, an H stability criterion of the state predictive observer is obtained in terms of linear matrix inequality. A new threshold computational method that conforms to the actual situation is proposed. Then, the thresholds of the false alarm rate （FAR） and miss detection rate （MDR） are presented by using our proposed method, which are also compared with the ones given in the existin~ literatures. Finally, some numerical simulations are shown to demonstrate the effectiveness of the proposed method.

关键词： Networked control system fault detection false alarm rate (FAR) miss detection rate (MDR) predictive control.

A-STC: auction-based spanning tree coverage algorithm for motion planning of cooperative robots

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2019年第1期20卷 18-31页

作者： guan-qiang GAO Bin xin School of Automation Beijing Institute of Technology Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing Advanced Innovation Center for Intelligent Robots and Systems

The multi-robot coverage motion planning(MCMP) problem in which every reachable area must be covered is common in multi-robot systems. To deal with the MCMP problem, we propose an efficient, complete, and off-line algorithm, named the "auction-based spanning tree coverage(A-STC)" algorithm. First, the configuration space is divided into mega cells whose size is twice the minimum coverage range of a robot. Based on connection relationships among mega cells, a graph structure can be obtained. A robot that circumnavigates a spanning tree of the graph can generate a coverage trajectory. Then, the proposed algorithm adopts an auction mechanism to construct one spanning tree for each robot. In this mechanism, an auctioneer robot chooses a suitable vertex of the graph as an auction item from neighboring vertexes of its spanning tree by heuristic rules. A bidder robot submits a proper bid to the auctioneer according to the auction vertexes' relationships with the spanning tree of the robot and the estimated length of its trajectory. The estimated length is calculated based on vertexes and edges in the spanning tree. The bidder with the highest bid is selected as a winner to reduce the makespan of the coverage task. After auction processes, acceptable coverage trajectories can be planned rapidly. Computational experiments validate the effectiveness of the proposed MCMP algorithm and the method for estimating trajectory lengths. The proposed algorithm is also compared with the state-of-the-art algorithms. The comparative results show that the A-STC algorithm has apparent advantages in terms of the running time and the makespan for large crowded configuration spaces.

关键词： Coverage motion planning Multi-robot system Auction algorithm Spanning tree coverage algorithm

CLM5.0对青藏高原冻融过程土壤温湿度的模拟及评估

在线全文

学校读者我要写书评

暂无评论

高原气象 2025年第1期44卷 32-45页

作者：张哲浩赖欣张戈姚思源张粟瑜成都信息工程大学大气科学学院/高原大气与环境四川省重点实验室/气候与环境变化联合实验室/成都平原城市气象与环境四川省野外科学观测研究站四川成都610225

利用1979-2018年中国区域地面气象要素驱动数据集(0.1°×0.1°)作为大气强迫资料,驱动CLM5.0(Community Land Model version 5.0)模拟了青藏高原地区1979-2018年的土壤温湿度变化。将土壤冻融过程划分为冻结期和非冻结期,通过两个阶段... 详细信息

利用1979-2018年中国区域地面气象要素驱动数据集(0.1°×0.1°)作为大气强迫资料,驱动CLM5.0(Community Land Model version 5.0)模拟了青藏高原地区1979-2018年的土壤温湿度变化。将土壤冻融过程划分为冻结期和非冻结期,通过两个阶段的CLM5.0模拟与站点观测资料、同化资料(GLDAS-Noah)、卫星遥感资料(MODIS土壤温度资料和ESA CCI-COMBINED土壤湿度资料)的对比验证,探讨CLM5.0模拟土壤温湿度在青藏高原的适用性。结果表明:(1)CLM5.0可较准确地描述站点土壤温湿度的动态变化,CLM5.0模拟的土壤温湿度与观测资料具有一致的变化特征且数值上较为接近。CLM5.0模拟的准确性高于GLDAS-Noah。CLM5.0对站点土壤温度的描述更为准确。(2)CLM5.0能够较准确地描述高原冻融过程中的土壤温湿度特征,CLM5.0模拟土壤温湿度与MODIS和ESA CCICOMBINED遥感资料在高原总体呈显著正相关,相关系数大多在0.9以上。CLM5.0对土壤温度的模拟能力相对较好,对非冻结期土壤湿度的模拟能力优于冻结期。CLM5.0整体高估了土壤温度,平均偏差大多在0~4℃之间。土壤湿度的平均偏差大多在-0.1~0.1 m^(3)·m^(-3)之间,非冻结期的平均偏差相对较小。(3)CLM5.0模拟、GLDAS-Noah、MODIS和ESA CCI-COMBINED遥感资料的土壤温湿度均具有相似的空间分布,其中土壤温度空间分布特征相似度更高。CLM5.0具有较高的空间分辨率和更为精细的土壤分层,对土壤温湿度细节的刻画更为完善。(4)CLM5.0模拟资料在高原整体呈增温变干趋势,MODIS和ESA CCI-COMBINED遥感资料整体呈增温增湿趋势。CLM5.0模拟的土壤温度变化趋势相对准确,土壤湿度的变化趋势则存在较大偏差。

关键词：青藏高原 CLM5.0模拟冻融过程土壤温湿度

同方期刊数据库

Rare-earth mediated dihydrogen activation and catalytic hydrogenation

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2021年第9期39卷 1017-1023页

作者： Yiwen guan Erli Lu xin Xu Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China School of Natural and Environmental Sciences Newcastle UniversityKing's RoadNewcastle Upon TyneNE17RUUK

This review covers H-H bond cleavage of dihydrogen(H2)mediated by structurally well-defined rareearth metal(scandium,yttrium and lanthanides)complexes,and their applications in homogenous catalysis,such as catalytic hydrogenation of unsaturated organic *** on the mechanism of the H-H bond cleavage,this review is organized in two parts:(1)σ-bond metathesis,and(2)non-σ-metathesis H2 *** latter is a new trend in this research field and is the emphasis of this *** H2 into inorganic rare-earth polyhydride complexes,albeit their potential applications as hydrogen-storage materiel,is not in the scope of this review.

关键词： Rare earths Dihydrogen activation Hydrogenation Homogeneous catalysis Cooperative effect

A low-frequency and broadband wave-insulating vibration isolator based on plate-shaped metastructures

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1171-1188页

作者： Wei WEI Feng guan xin FANG College of Intelligent Science National University of Defense TechnologyChangsha410073China Naval Research Academy Beijing100161China

A metamaterial vibration isolator,termed as wave-insulating isolator,is proposed,which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave *** consists of plate-shaped metacells,whose symmetric and antisymmetric local resonant modes offer several low and broad mode bandgaps although the complete bandgap remains high and *** bandgap mechanisms,vibration isolation properties,effects of key parameters,and robustness to complex conditions are *** experimentally demonstrated,the wave-insulating isolator can improve the vibration insulation in the ranges of[50 Hz,180 Hz]and[260 Hz,400 Hz]by 15 dB and 25 dB,respectively,in contrast to the conventional isolator with the same first resonant frequency.

关键词： metamaterial and metastructure vibration isolation bandgap wave insulation plate