同步辐射标定平面镜反射率不确定度分析方法研究   总被引：1，自引：0，他引：1  

陈伯伦  杨正华  曹柱荣  董建军  侯立飞  崔延莉  江少恩  易荣清  李三伟  刘慎业  杨家敏 《海洋学报》2010,32(10):7078-7085

为了提高多通道软X射线能谱仪的测量精度,2009年在北京同步辐射(BSRF)软X束线源上对多种材料的掠入射平面镜的反射率进行了标定.在标定实验的基础上,对光源的单色性、高次谐波以及源强稳定性、探测器响应一致性和数据采集统计误差等多项不确定因素进行了评估,给出了反射率的修正方法和相应的不确定度分析结果.  相似文献   

基于阈值光电子-光离子符合技术的分子离子光谱和解离动力学研究     

唐小锋  牛铭理  周晓国  刘世林 《海洋学报》2010,32(10):6940-6947

对电子和离子同时采用速度聚焦电场收集的阈值光电子-光离子符合成像谱仪能够有效提高电子的收集效率和能量分辨率.利用该符合成像谱仪,开展了Xe/Ar/Ne 惰性混合气体及NO 分子的阈值光电子谱、阈值光电子-光离子符合质谱和质量选择的符合光谱等实验研究,精确测量了NO 分子的电离势,并且获得了NO⁺离子振动态分辨的X¹Σ⁺,c³Π和B¹Π态光谱.还进一步研究了NO^{+ 相似文献}   

On the magnetic field diffusion in mhd modeling of the inner coma of comet halley     

M. D. Kartalev  V. I. Nikolova 《地球物理与天体物理流体动力学》2013,107(1-2):145-168

Abstract

Some approaches of one-dimensional time-dependent magneto-hydrodynamic modeling of the structure of the inner coma of comet Halley are considered. The influence of the magnetic field diffusion on this structure is studied. The solution of Cravens (1989) approach containing classic magnetic diffusion is compared with an approach containing a specific diffusion, caused by non-instantaneous mass-loading of new ions. A case with no magnetic field is also considered. Common features of all the solutions are obtained. Special attention is paid to the sharp velocity jump, synchronized with a local density pick. Some differences between two types of magnetic field diffusion are discussed. A possible connection is supposed between this consideration and the large-scale shock fitting modeling of the solar plasma-comet interaction.  相似文献   

环境星CCD数据大气校正研究   总被引：1，自引：0，他引：1  

孙源  顾行发  余涛  高海亮 《国土资源遥感》2010,(4)

利用6S模型和同步气象资料,对国产环境与灾害监测预报小卫星HJ-1 A的CCD1传感器数据进行了大气校正和反射率反演。同时对CCD1传感器1～4波段大气校正前后的反射率变化进行了对比研究,发现大气校正后的1～3波段的地面反射率明显降低,4波段的地面反射率升高;利用同步野外实测地面数据对大气校正后的反射率数据进行了检验,两者结果基本一致;此外,还进行了定量化误差分析,以同步野外实测地面数据作为标准,将大气校正后的反射率数据与之对比,分析了可能带来误差的原因。结果表明,利用6S大气校正方法能够有效去除HJ-1 A星CCD图像的大气影响,获取地物绝对反射率。  相似文献   

Flood forecasting with a watershed model: a new method of parameter updating     

XIAOLIU YANG  CLAUDE MICHEL 《水文科学杂志》2013,58(4):537-546

Abstract

Flood forecasting is of prime importance when it comes to reducing the possible number of lives lost to storm-induced floods. Because rainfall-runoff models are far from being perfect, hydrologists need to continuously update outputs from the rainfall-runoff model they use, in order to adapt to the actual emergency situation. This paper introduces a new updating procedure that can be combined with conceptual rainfall-runoff models for flood forecasting purposes. Conceptual models are highly nonlinear and cannot easily accommodate theoretically optimal methods such as Kalman filtering. Most methods developed so far mainly update the states of the system, i.e. the contents of the reservoirs involved in the rainfall-runoff model. The new parameter updating method proves to be superior to a standard error correction method on four watersheds whose floods can cause damage to the greater Paris area. Moreover, further developments of the approach are possible, especially along the idea of combining parameter updating with assimilation of additional data such as soil moisture data from field measurements and/or from remote sensing.  相似文献   

Force free fields and coronal heating part I. The formation of current sheets     

A. A. Van Ballegooijen 《地球物理与天体物理流体动力学》2013,107(3-4):181-211

  相似文献   

Compact and tunable mid-infrared source based on a 2 μm dual-wavelength KTiOPO₄ intracavity optical parametric oscillator     

耿优福  谭晓玲  李学金  姚建铨 《海洋学报(英文版)》2010,29(11)

Using a double resonant KTiOPO₄ (KTP) intracavity optical parametric oscillator operating at degenerated point of 2 μm, we demonstrate a unique mid-infrared source based on difference frequency generation in GaSe crystal. The output tuning range is 8.42-19.52 μm, and a peak power of 834 W for type-I phase matching scheme and 730 W for type-II phase matching scheme are achieved. Experimental results show that this oscillator is a good alternative to the generator of a compact and tabletop mid-infrared radiation with a widely tunable range.  相似文献   

The concept of ecological succession applied to phytoplankton over four consecutive years in five ponds featuring a salinity gradient     

Hajer Khemakhem  Jannet Elloumi  Mahmoud Moussa  Lotfi Aleya  Habib Ayadi 《Estuarine, Coastal and Shelf Science》2010

The distribution of phytoplankton abundance, biomass and species composition coupled with environmental factors and metazooplankton was studied relatively intensively and over a period of four consecutive years in five ponds featuring a gradient of increasing salinity from near to that of sea water to a nine-fold concentration from 2000 to 2003. The results indicate that the physical characteristics of the water (temperature and salinity) were quite similar over the years. Nutrients, which were concentrated in pond A1, decreased with increases in salt concentration. The composition of the phytoplankton community showed strong seasonality. Diatoms dominated in the first ponds A1, A16 and C2-1, followed by dinoflagellates. Chlorophyceae dominated the phytoplankton community in the hypersaline ponds M2 and TS. Cyanobacteriae were relatively abundant in ponds M2 and TS. The highest phytoplankton density and biomass were found in the ponds with the highest salinity due to the proliferation of Dunaliella salina (Chlorophyta: Volvocales). The inter-annual study of phytoplankton succession in the Sfax solar salterns showed slight differences among the years of study due to the stability of the environmental conditions. Phytoplankton communities were permanently primitive, stage 1 – structured as they failed to build complexity because of salt stress which operates for longer and above any other variables. This reduced frequency of disturbance to the existing course of regulation, allowed the community to “mature” from its “primitive” state, rather than experience frequent structural setbacks.  相似文献   

Effect of slow-solvent-vapour treatment on performance of polymer photovoltaic devices     

冯志慧  侯延冰  师全民  刘小君  滕枫 《海洋学报(英文版)》2010,29(9)

In this work, enhanced poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk-heterojunction photovoltaic devices are achieved via slow-solvent-vapour treatment. The correlations between the morphology of the active layer and the photovoltaic performance of polymer-based solar cell are investigated. The active layers are characterized by atomic force microscopy and optical absorption. The results show that slow-solvent-vapour treatment can induce P3HT self-organization into an ordered structure, leading to the enhanced absorption and efficient charge transport.  相似文献   

Are peatlands in different states with respect to their thermodynamic behaviour? A simple test of peatland energy and entropy budgets     

Fred Worrall  Ross Morrison  Chris Evans  Joerg Kaduk  Susan Page  Alex Cumming  Mark Rayment  Nicholas Kettridge 《水文研究》2021,35(12):e14431

Whilst all ecosystems must obey the second law of thermodynamics, these physical bounds and controls on ecosystem evolution and development are largely ignored across the ecohydrological literature. To unravel the importance of these underlying restraints on ecosystem form and function, and their power to inform our scientific understanding, we have calculated the entropy budget of a range of peat ecosystems. We hypothesize that less disturbed peatlands are ‘near equilibrium’ with respect to the second law of thermodynamics and thus respond to change by minimizing entropy production. This ‘near equilibrium’ state is best achieved by limiting evaporative losses. Alternatively, peatlands ‘far-from-equilibrium’ respond to a change in energy inputs by maximizing entropy production which is best achieved by increasing evapotranspiration. To test these alternatives this study examined the energy balance time series from seven peatlands across a disturbance gradient. We estimate the entropy budgets for each and determine how a change in net radiation (ΔR_n) was transferred to a change in latent heat flux (ΔλE). The study showed that: (i) The transfer of net radiation to latent heat differed significantly between peatlands. One group transferred up to 64% of the change in net radiation to a change in latent heat flux, while the second transferred as little as 27%. (ii) Sites that transferred the most energy to latent heat flux were those that produced the greatest entropy. The study shows that an ecosystem could be ‘near equilibrium’ rather than ‘far from equilibrium’.  相似文献