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Effects of Turbulent Dispersion of Atmospheric Balance Motions of Planetary Boundary Layer 被引量:1
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作者 刘式适 黄伟 荣平平 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1992年第2期147-156,共10页
New Reynolds' mean momentum equations including both turbulent viscosity and dispersion are used to analyze atmospheric balance motions of the planetary boundary layer. It is pointed out that turbulent dispersion ... New Reynolds' mean momentum equations including both turbulent viscosity and dispersion are used to analyze atmospheric balance motions of the planetary boundary layer. It is pointed out that turbulent dispersion with r 0 will increase depth of Ekman layer, reduce wind velocity in Ekman layer and produce a more satisfactory Ekman spiral lines fit the observed wind hodograph. The wind profile in the surface layer including tur-bulent dispersion is still logarithmic but the von Karman constant k is replaced by k1 = 1 -2/k, the wind increasesa little more rapidly with height. 展开更多
关键词 effects of Turbulent Dispersion of Atmospheric Balance Motions of Planetary Boundary Layer
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Effective Potential of a Two-State Model for Molecular Motor
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作者 HANYing-Rong ZHAOTong-Jun +1 位作者 ZHAN-Yong YANWei-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期377-381,共5页
We study force generation and motion of molecular motors using a simple two-state model in the paper.Asymmetric and periodic potential is adopted to describe the interaction between motor proteins and filaments that a... We study force generation and motion of molecular motors using a simple two-state model in the paper.Asymmetric and periodic potential is adopted to describe the interaction between motor proteins and filaments that are periodic and polar. The current and the slope of the effective potential as functions of the temperature and transition rates are calculated in the two-state model. The ratio of the slope of the effective potential to the current is also calculated. It is shown that the directed motion of motor proteins is relevant to the effective potential. The slope of the effective potential corresponds to an average force. The non-vanishing force therefore implies that detailed balance is broken in the process of transition between different states. 展开更多
关键词 Brownian particle directed motion Fokker-Planck equation effective potential detailed balance
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Effect of the Lower Boundary Position of the Fourier Equation on the Soil Energy Balance
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作者 孙菽芬 张霞 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2004年第6期868-878,共11页
In this study, the e?ect of the lower boundary position selection for the Fourier equation on heat transfer and energy balance in soil is evaluated. A detailed numerical study shows that the proper position of the l... In this study, the e?ect of the lower boundary position selection for the Fourier equation on heat transfer and energy balance in soil is evaluated. A detailed numerical study shows that the proper position of the lower boundary is critical when solving the Fourier equation by using zero heat ?ux as the lower boundary condition. Since the position de?nes the capacity of soil as a heat sink or source, which absorbs and stores radiation energy from the sky in summer and then releases the energy to the atmosphere in winter, and regulates the deep soil temperature distribution, the depth of the position greatly in?uences the heat balance within the soil as well as the interaction between the soil and the atmosphere. Based on physical reasoning and the results of numerical simulation, the proper depth of the position should be equal to approximately 3 times of the annual heat wave damping depth. For most soils, the proper lower boundary depth for the Fourier equation should be around 8 m to 15 m, depending on soil texture. 展开更多
关键词 thermal conductivity lower boundary position effect on heat balance
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Strong Interaction Effect on Jet Energy Loss with Detailed Balance
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作者 Jing-Ya Zhang Luan Cheng 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第10期18-22,共5页
The strong force effect on gluon distribution of quark-gluon plasma and its influence on jet energy loss with detailed balance are studied. We solve the possibility equation and obtain the value of non-extensive param... The strong force effect on gluon distribution of quark-gluon plasma and its influence on jet energy loss with detailed balance are studied. We solve the possibility equation and obtain the value of non-extensive parameter q. In the presence of strong interaction, more gluons stay at low-energy state than the free gluon case. The strong interaction effect is found to be important for jet energy loss with detailed balance at intermediate jet energy. The energy gain via absorption increases with the strong interaction. This will affect the nuclear modification factor RAA and the parameter of q at intermediate jet energy. 展开更多
关键词 Strong Interaction effect on Jet Energy Loss with Detailed Balance QCD
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Vegetation structure and edaphic factors in veredas reflect different conservation status in these threatened areas
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作者 Yule Roberta Ferreira Nunes Camila Silveira Souza +5 位作者 Islaine Francielly Pinheiro de Azevedo Odirlei Simôes de Oliveira Leidivan Almeida Frazão Rúbia Santos Fonseca Rubens Manoel dos Santos Walter Viana Neves 《Forest Ecosystems》 SCIE CSCD 2022年第3期387-395,共9页
Background:In Cerrado humid areas,veredas are considered as hygrophilous communities,marked by the presence of the Mauritia flexuosa palm tree emerging in the wetter zones.Changes in veredas ecosystems due to drought ... Background:In Cerrado humid areas,veredas are considered as hygrophilous communities,marked by the presence of the Mauritia flexuosa palm tree emerging in the wetter zones.Changes in veredas ecosystems due to drought and changes in the water table,which represent important areas for biodiversity maintenance in the Brazilian cerrado,can lead to the emergence of new landscapes and ecosystems.Assuming that the veredas are changed in species composition due to anthropogenic factors,in this study,we evaluated the flora composition and described the current vegetation profile of two veredas under different disturbances levels that are located in the north of Minas Gerais State,Brazil.Results:Altogether,2,268 individuals of 91 species belonging to 36 families were recorded.Our results demonstrated that the studied veredas were floristically different in terms of the arboreous-shrubby species composition,richness,and diversity.Despite the hygrophilous forest formations and open areas in the two veredas present typical species from these environments(same species with high importance values),the drought in the water table caused an expansion of Cerrado species in the open areas and in the hygrophilous forest.Furthermore,in the hygrophilous forest there was an increase in the abundance of species that occur in less saturated soils.Conclusion:Our results demonstrate that the studied veredas are changing in species composition due to anthropogenic factors which leads to the drought of these formations(water balance effect).These anthropogenic effects cause a modification with the expansion and increase in the abundance of typical species of other areas of Cerrado and resistant to less saturated soils,leading to the veredas collapse.Finally,future studies should investigate other veredas on a broader scale to detect changes in the water table that lead to a consequent change in vegetation structure.In this way,we will have support for the conscientious management and conservation of these areas that represent equilibrium places for the Cerrado biome. 展开更多
关键词 CERRADO CONSERVATION Palm swamp Plant distribution Climate change Water balance effect Vereda drought Phytosociological analysis
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Research on Full Vector Dynamic Balancing Algorithm for Rotors
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作者 YANG Zhi-han WANG Wen-chao 《International Journal of Plant Engineering and Management》 2018年第1期18-23,共6页
Influence coefficient method and the modal balancing method are often used in the dynamic balancing in the past days. These methods sometimes exist a lot of big measurement errors. So, in order to make these errors mu... Influence coefficient method and the modal balancing method are often used in the dynamic balancing in the past days. These methods sometimes exist a lot of big measurement errors. So, in order to make these errors much smaller, and to use the vibration information of the rotor more sufficiently, at last, we put forward the full vector dynamic balancing algorithm. Though the theoretical analysis, and the experiment tests, we can compare with the new method and the old method , study the relationship between the dynamic balancing and the rotation equipment, and the direction of the development. The full vector dynamic balancing algorithm theory can be inferred from the Jeffcott rotor. To compare with the methods which are mentioned before, we can find that the full vector dynamic balancing algorithm is much better than the influence coefficient method and the modal balancing method. We can use the MATLAB program to prove that the full vector dynamic balancing algorithm is much better. So the conclusion is completely right. 展开更多
关键词 full vector dynamic balancing algorithm unbalanced response balancing effect MATLAB
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