检索结果-南通市图书馆

基于遥感的1984一2019年查干湖及周边湖泊透明度变化

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

湖泊科学 2025年第1期37卷 328-338页

作者：赵方睿王强穆春生刘阁温志丹陶慧宋开山东北师范大学生命科学学院长春130024 中国科学院东北地理与农业生态研究所长春130102

湖泊透明度是衡量水质变化和湖泊水生生态系统健康的重要指标。湖泊透明度一般通过塞氏盘现场观测获得,其变化主要由水体中非藻类颗粒物、藻类和黄色物质(CDOM)浓度共同决定,因此可以通过光学遥感进行反演。本研究基于20042009年8次查... 详细信息

湖泊透明度是衡量水质变化和湖泊水生生态系统健康的重要指标。湖泊透明度一般通过塞氏盘现场观测获得,其变化主要由水体中非藻类颗粒物、藻类和黄色物质(CDOM)浓度共同决定,因此可以通过光学遥感进行反演。本研究基于20042009年8次查干湖实地采样获得的132条透明度数据,通过分析同步Landsat天顶反射率产品数据(TOA)不同波段组合与透明度之间的相关性,发现以红波段和蓝波段比值和红绿蓝波段均值AV(B3,B1)组合建立的透明度反演模型精度最高,误差最小,进而基于此模型反演了19842019年查干湖以及周边湖泊透明度。结果表明:查干湖透明度范围在1.0~63.0 cm之间,年均值为17.6 cm。查干湖透明度年均值变化分为两个阶段:19842001年间透明度波动范围较大,没有明显趋势;20022019年期间呈上升趋势(2.3 cm/10 a)。查干湖透明度与风速、降水量、湖泊面积和归一化植被指数具有一定的相关性。通过长时间尺度上遥感监测查干湖水体透明度的时空格局变化,分析其变化特征与规律,可为查干湖流域生态治理提供科学依据。

关键词：查干湖透明度 Landsat 遥感

融合快速边缘注意力的Transformer跟踪算法

在线全文

学校读者我要写书评

暂无评论

计算机工程与应用 2025年第1期61卷 221-231页

作者：薛紫涵葛海波王淑贤安玉杨雨迪西安邮电大学电子工程学院西安710121

针对长期目标跟踪中出现模型退化和跟踪漂移的问题,提出了一种融合快速边缘注意力的Transformer跟踪算法TransFEA(fast edge attention on Transformer)。使用ResNet-50作为Siamese网络的骨干网络,并在其每个残差块后端引入注意力网络... 详细信息

针对长期目标跟踪中出现模型退化和跟踪漂移的问题,提出了一种融合快速边缘注意力的Transformer跟踪算法TransFEA(fast edge attention on Transformer)。使用ResNet-50作为Siamese网络的骨干网络,并在其每个残差块后端引入注意力网络进行特征提取,增强目标的关键信息和全局信息;边缘注意力网络(edge attention network,EA)提取模板与搜索区域的特征向量,快速注意力网络(fast attention network,FA)计算注意响应值,确定两个区域的相似度,以此调整目标位置。设计多层感知器预测边界框,避免过多超参数,使跟踪器实现了准确性与轻量化的平衡。实验结果表明,TransFEA在LaSOT数据集上成功率和准确率分别为65.3%、69.1%,运行可以达到90 FPS,提高了长期跟踪的成功率和准确率。

关键词： Transformer网络边缘注意力网络快速注意力网络多层感知器

Some Kazhdan-Lusztig Coefficients of Affine Weyl Group of Type B_(2)

在线全文

学校读者我要写书评

暂无评论

Algebra Colloquium 2021年第4期28卷 541-554页

作者： ge Feng Liping wang Shanghai Center for Mathematical Sciences Fudan University Songhu Road 2005Shanghai 200433China College of Science Beijing University of Civil Engineering and Architecture Yong Yuan RoadBeijing 102699China

Let(W,S)be the affine Weyl group of type B_(2),on which we consider the length function e from W to N and the Bruhat order≤.For y 详细信息

Let(W,S)be the affine Weyl group of type B_(2),on which we consider the length function e from W to N and the Bruhat order≤.For yget some consequences using left or right strings and some properties of leading coefficients.

关键词： Kazhdan-Lusztig polynomials left(resp.righttwo-sided)cells a-function affine Weyl groups leading coefficients

Heterogeneous uptake of NO_2 on soils under variable temperature and relative humidity conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2012年第10期24卷 1759-1766页

作者： Lei wang Weigang wang Maofa ge Beijing National Laboratory for Molecular Science (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China. Beijing National Laboratory for Molecular Science (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Peking University Beijing 100871 China

Heterogeneous reactions of nitrogen dioxide （NO2） on soils collected from Dalian （S 1） and Changsha （S2） were investigated over the relative humidity （RH） range of 5%-80% and temperature range of 278-328 K using a horizontal coated-wall flow tube. The initial uptake coefficients of NO2 on S2 exhibited a decreasing trend from （10 ± 1.3） × 10-8 to （3.1 ± 0.5） x 10-8 with the relative humidity increasing from 5% to 80%. In the temperature effect studies, the initial uptake coefficients of S1 and S2 decreased from （10± 1.2） × 10-8 to （3.8 ± 0.5） × 10-8 and from （16± 2.2） × 10-8 to （3.8 ±0.4） × 10-8 when temperature increased from 278 to 288 K for S1 and from 278 to 308 K for S2, respectively. As the temperature continued to increase, the initial uptake coefficients of S1 and S2 returned to （7.9 ± 1.1）× 10-8 and （20 ± 3.1） × 10-8 at 313 and 328 K, respectively. This study shows that relative humidity could influence the uptake kinetics of NO2 on soil and temperature would impact the heterogeneous chemistry of NO2.

关键词： heterogeneous reactions soil particles uptake coefficients temperature dependence relative humidity effect

Effect of particle size on the thermal performance of NaNO3/SiC)2/C composite phase-change materials

在线全文

学校读者我要写书评

暂无评论

Particuology 2019年第3期17卷 169-175页

作者： Liang Liu Liqiong wang Weichun ge Yanfeng ge Yun Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China State Grid Liaoning Electric Power Supply Co. Ltd. Shenyang 110004 China

Storage of thermal energy is a key technology for energy conservation and application of renewable energy sources. In this paper, the thermal performance of inorganic composite phase-change materials (PCMs;NaNO3/SiO2/C) is studied under extreme thermal conditions and the effect of raw particle size is examined. We designed a thermal shock test platform with a diffusive combustion system and in-situ infrared thermal imaging. The influences of the heat flux magnitude and exposure time on the performance of the PCMs were examined under vertical thermal shock conditions. Leakage of molten salt in the composite PCMs was observed as the heat flux reached a threshold point. The morphology and thermal properties were characterized by ex-situ SEM, XRD, DSC, and BET. Raw particles with sizes in the range of 105-500 μm were used to synthesize the composite material and examine its role in thermal shock behavior. Our experiments showed that deterioration of the thermal storage density was slowed as the particle size was increased. This work provides useful guidance for improving the anti-thermal shock ability of future material designs.

关键词： Thermal storage Phase change material Particle size Thermal shock Decomposition temperature

Influence of the Gaussian colored noise and electromagnetic radiation on the propagation of subthreshold signals in feedforward neural networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2021年第4期64卷 847-857页

作者： ge MengYan wang GuoWei JIA Ya Department of Physics Central China Normal UniversityWuhan 430079China

Iterative methods are used to simulate the in vitro feedforward neural networks in physiological *** can be propagated to a minimum of ten ***,the discharge activity of each group will be more *** feedforward neural networks have a wide range of applications in machine learning,and the weight of synapses considerably influences the propagation of weak ***,we investigated the effect of Gaussian colored noise and electromagnetic radiation on the propagation of the subthreshold excitatory postsynaptic current signals in the input layer of the multilayer Izhikevich neural feedforward *** the absence of electromagnetic radiation,the excitatory postsynaptic current signal is stably propagated and amplified in multilayer feedforward neural networks under the optimal Gaussian colored noise strength or correlation time in the output layer of the *** with the case in which there is no electromagnetic radiation,the presence of electromagnetic radiation slightly reduces the propagation of weak ***,the time required to propagate the excitatory postsynaptic current signal to the output layer increases with the increasing feedback *** feedforward neural network considered in this study is a considerably simple *** complex structures,such as backward connection and delayed feedback,can be observed in real biological ***,the next step will be to study more complex neural models with neuron models based on the physiological experimental data and compare them with real biological ***,the study of neural networks can be combined with an experimental study about the auditory nervous system of bats to understand the biological mechanism associated with the auditory system function of bats from two perspectives.

关键词： feedforward neural network colored noise electromagnetic radiation signal propagation

Reflected shock/turbulent boundary layer interaction structure analysis based on large eddy simulation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第5期34卷 364-372页

作者： Dongdong ZHONG Lixu wang Ning ge College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Nanjing Engineering Institute of Aircraft Systems AVICNanjing 210016China

In order to understand the physical phenomenon of the reflected shock/turbulent boundary layer interaction,the Large Eddy Simulation(LES)is conducted to investigate shock wave and turbulent boundary layer interaction in a 12°compression ramp with inlet high Mach number of ***/recycling method is used as inflow turbulence generation technique and validated on a supersonic flat plate turbulent boundary *** flow field of recycling plane in the plate computation domain is obtained to give the inlet boundary condition for the LES *** paper focuses on the reflected shock/turbulent boundary layer interaction region,where the fine flow structure and instantaneous flow field are analyzed in *** is found that the unsteady motion of the shock wave leads to the increase of wall pressure fluctuation.

关键词： Large eddy simulation Reflected STBLI Rescaling/recycling method Shock motion Turbulent

general Frequency-Intensity Cooperation in Stable Multimode Lasers

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1999年第7期16卷 510-512页

作者： wang Kai-ge Department of Physics Beijing Normal UniversityBeijing 100875

In a homogeneously broadened laser models we find a simple and general law for stable multimode operatioiij which shows a nonlinear cooperative relationship between the frequencies and intensities of laser modes.

关键词： laser Lasers Intensity

Approximate Scaling Behaviour of Local Spectral Density of States at Relatively Weak Perturbation: a Schematic Shell Model

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 Physics Letters 2001年第6期18卷 731-733页

作者： wang Wen-ge Department of Physics South-east UniversityNanjing 210096 International Center for the Study of Dynamical Systems 22100 ComoItaly Centre for Nonlinear StudiesHong Kong Baptist UniversityHong KongChina

For a schematic shell model,we show numerically that,contrary to the behaviour of eigenfunctions,the shapes of the so-called local spectral density of states become close to their forms at extremely strong perturbation(after rescaling)even when the perturbation is relatively *** same phenomenon is also found for the random version of the schematic shell *** suggest that this property of the local spectral density of states may be common to models in which the Hamiltonian matrices in independent particle states have a banded and regular structure.

关键词： structure perturbation states