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Stem and leaf traits as co-determinants of canopy water flux

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Plant Diversity 2019年第4期41卷 258-265页

作者： Jianguo Gao kai tian Department of Ecology College of Urban and Environmental SciencesKey Laboratory for Earth Surface Processes of the Ministry o f EducationPeking UniversityNo.5 Yiheyuan Road Haidian DistrictBeijing100871PR China School of Life Sciences Nanjing UniversityNanjing210023PR China Coastal Ecosystems Research Station of the Yangtze River Estuary Ministry of Education Key Laboratory for Biodiversity Science and Ecological EngineeringInstitute of Biodiversity ScienceFudan UniversityShanghai200438PR China Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems Chinese Academy o f SciencesSouth China Botanical GardenGuangzhou510650PR China

Transpiration through stomata in tree canopies plays an important role in terrestrial water ***, the empirical relationship between leaf stomata anatomy and canopy stomatal conductance（Gs） is surprisingly rare, thereby the underlying biological mechanisms of terrestrial water flux are not well elucidated. To gain further insight into these mechanisms, we reanalyzed the dataset of Gspreviously reported by Gao et al.（2015） using a quantile regression model. The results indicated that the reference Gs(Gsref, Gs at 1 kPa) was negatively correlated with wood density at each quantile, which confirmed previous data; however, Gsrefwas significantly correlated with stomatal density at the 0.6 quantile, i.e., 450 stomata mm-2. This highlighted the potential of using stomatal density as a trait to predict canopy water flux. A conceptual model of co-determinants of xylem and stomatal morphology suggests that these traits and their coordination may play a critical role in determining tree growth,physiological homeostatic response to environmental variables, water use efficiency, and drought resistance.

关键词： Gsref Quantile regression Stomatal density Water flux Wood density

Electromagnetohydrodynamic (EMHD) flow of fractional viscoelastic fluids in a microchannel

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Applied Mathematics and Mechanics(English Edition) 2022年第6期43卷 917-930页

作者： Shujuan AN kai tian Zhaodong DING Yongjun JIAN School of Mathematical Science Inner Mongolia UniversityHohhot 010021China

This study investigates the electromagnetohydrodynamic(EMHD)flow of fractional viscoelastic fluids through a microchannel under the Navier slip boundary *** flow is driven by the pressure gradient and electromagnetic force where the electric field is applied horizontally,and the magnetic field is vertically(upward or downward).When the electric field direction is consistent with the pressure gradient direction,the changes of the steady flow rate and velocity with the Hartmann number Ha are irrelevant to the direction of the magnetic field(upward or downward).The steady flow rate decreases monotonically to zero with the increase in *** contrast,when the direction of the electric field differs from the pressure gradient direction,the flow behavior depends on the direction of the magnetic field,i.e.,symmetry breaking ***,when the magnetic field is vertically upward,the steady flow rate increases first and then decreases with *** the magnetic field is reversed,the steady flow rate first reduces to zero as Ha increases from *** Ha continues to increase,the steady flow rate(velocity)increases in the opposite direction and then decreases,and finally drops to zero for larger *** increase in the fractional calculus parameterαor Deborah number De makes it take longer for the flow rate(velocity)to reach the steady *** addition,the increase in the strength of the magnetic field or electric field,or in the pressure gradient tends to accelerate the slip velocity at the *** the other hand,the increase in the thickness of the electric double-layer tends to reduce it.

关键词： electromagnetohydrodynamic(EMHD)flow fractional viscoelastic fluid symmetry breaking

Sensor node-assisted asynchronous cooperative spectrum sensing for cognitive radio network

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The Journal of China Universities of Posts and Telecommunications 2014年第5期21卷 17-23页

作者： CAO kai-tian WANG Dong-lin Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications National Mobile Communications Research Laboratory Southeast University Department of Electrical and Computer Engineering New York Institute of Technology (Nanjing Campus)

In order to take advantage of the asynchronous sensing information, alleviate the sensing overhead of secondary users （SUs） and improve the detection performance, a sensor node-assisted asynchronous cooperative spectrum sensing （SN-ACSS） scheme for cognitive radio （CR） network （CRN） was proposed. In SN-ACSS, each SU is surrounded by sensor nodes （SNs）, which asynchronously make hard decisions and soft decisions based on the Bayesian fusion rule instead of the SU. The SU combines these soft decisions and makes the local soft decision. Finally, the fusion center （FC） fuses the local soft decisions transmitted from SUs with different weight coefficients to attain the final soft decision. Besides, the impact of the statistics of licensed band occupancy on detection performance and the fact that different SNs have different sensing contributions are also considered in SN-ACSS scheme. Numerical results show that compared with the conventional synchronous cooperative spectrum sensing （SCSS） and the existing ACSS schemes, SN-ACSS algorithm achieves a better detection performance and lower cost with the same number of SNs.

关键词： cognitive radio asynchronous cooperative spectrum sensing Bayesian fusion rule ON-OFF model soft decision

On the energy conversion in electrokinetic transports

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Applied Mathematics and Mechanics(English Edition) 2022年第2期43卷 263-274页

作者： Zhaodong DING Long CHANG kai tian Yongjun JIAN School of Mathematical Science Inner Mongolia UniversityHohhotInner Mongolia010021China School of Statistics and Mathematics Inner Mongolia University of Finance and EconomicsHohhotInner Mongolia010021China

Energy conversion in micro/nano-systems is a subject of current research,among which the electrokinetic energy conversion has attracted extensive ***,there exist two different definitions on the electrokinetic energy conversion efficiency in literature.A few researchers defined the efficiency using the pure pressure-driven flow rate,while other groups defined the efficiency based on the flow rate with the inclusion of the effect of the streaming potential *** this work,both definitions are investigated for different fluid types under the periodic electrokinetic flow *** Newtonian fluids,the two definitions give similar ***,for viscoelastic fluids,these two definitions lead to significant *** efficiency defined by the pure pressure-driven flow rate even exceeds 100%in a certain range of the *** result shows that in the case of viscoelastic flow,it is incorrect to define the energy conversion efficiency by pure pressure-driven flow *** the same time,the reason for this problem is clarified through comprehensive analysis.

关键词： electrokinetic transport energy conversion efficiency Newtonian fluid viscoelastic fluid streaming potential field

1-D Directional Filter Based Texture Descriptor in Fractional Fourier Domain

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Journal of Harbin Institute of Technology(New Series) 2015年第5期22卷 125-128页

作者： kai tian Hongzhang Jin Liying Zheng College of Automation Harbin Engineering University College of Computer Science and Technology Harbin Engineering University

Texture analysis is a fundamental field in computer vision. However,it is also a particularly difficult problem for no universal mathematical model of real world textures. By extending a new application of the fractional Fourier transform( Fr FT) in the field of texture analysis,this paper proposes an Fr FT-based method for describing textures. Firstly,based on the Radon-Wigner transform,1-D directional Fr FT filters are designed to two types of texture features,i. e.,the coarseness and directionality. Then,the frequencies with maximum and median amplitudes of the Fr FT of the input signal are regarded as the output of the 1-D directional Fr FT filter. Finally,the mean and the standard deviation are used to compose of the feature vector. Compared to the WD-based method,three benefits can be achieved with the proposed Fr FT-based method,i. e.,less memory size,lower computational load,and less disturbed by the cross-terms. The proposed method has been tested on16 standard texture images. The experimental results show that the proposed method is superior to the popular Gabor filtering-based method.

关键词： fractional Fourier transform texture analysis Radon-Wigner transform 1-D directional window

Improving the Catalytic Activity of Au25 Nanocluster by Peeling and Doping

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Chinese Journal of Chemistry 2017年第5期35卷 567-571页

作者： Man-bo Li Shi-kai tian Zhikun Wu Key Laboratory of Materials Physics Anhui Key Laboratory of Nanomaterials and Nanotechnology CAS Center for Excellence in Nanoscience Institute of Solid State Physics Chinese Academy of Sciences Hefei Anhui 230031 China Department of Chemistry University of Science and Technology of China Hefei Anhui 230026 China

Tuning the nanoclusters＇ compositions and structures is critical for the performance improvement of ***,a well-known Au25（SCH2CH2Ph）18 （Au25 for short） nanocluster has been transformed to a rare cadmium doped gold nanocluster [Au13Cd2（PPh3）6（SC2H4Ph）6（NO3）2]2Cd（NO3）4 （Au26Cd5 for short） by peeling and *** Au25 exhibits no catalytic activity toward A3-coupling reaction under the investigated conditions,the novel cadmium doped gold nanocluster Au26Cd5 shows high catalytic activity,as well as good recyclability and substrate tolerance for the same *** high catalytic activity is attributed to the cooperation between the exerted cadmium atoms and the neighbor gold atoms on the surface of Au13 *** work has important implication for the tuning of nanoclusters＇ compositions and structures targeting the improvement of catalytic performance by some unusual but effective strategies.

关键词： peeling doping gold nanocluster A^3-coupling reaction catalysis

Density Functional Theory Study of Water Diffusion and Clustering on Pd(111)

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Chinese Journal of Structural Chemistry 2006年第8期25卷 909-914页

作者： CHEN Jin-Wen TU Xue-Yan tian kai DAI Shu-Shan School of Chemical Science and Technology Yunnan University Kunming 650091 China School of Chemistry. and Biotechnology Yunnan Nationalities University Kunming 650031 China School of Chemistry and Chemical Engineering Hunan Universi of Science and Technology Xiangtan 411201 China

The internal structures as well as adsorption and hopping energies of monomers, dimers, trimers, tetramers, pentamers and hexamers of water on Pd（111） have been studied by density functional theory （DFT） plane-wave pseudopotential method which performs the firstprinciples quantum-mechanical calculations to explore the properties of crystals and surfaces in materials. Based on the calculations, we suppose that their absorption is via one water molecule for monomers, dimmers and trimers, but three water molecules for pentamers and hexamers. Moreover, there is one water molecule bonding with Pd atom by O atom in pentamers and hexamers, which explains why pentamers and hexamers are stable. The binding energies of polymers may be used to explain why the trimer comes close to two nearby monomers to form a stable pentamer instead of tetramer. And the difference of mobility of small water clusters is due to their different hopping energies.

关键词： density functional theory Pd(111) surface water diffusion and clustering binding energy hopping energy

Growth of Kentucky Bluegrass as Influenced by Nitrogen and Trinexapacethyl

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Agricultural Sciences in China 2009年第12期8卷 1498-1502页

作者： WANG Xiao-ying HU tian-ming WANG Quan-zhen tian Li-min ZHANG Xiao-ling tian kai College of Animal Science and Technology Northwest A&F University Yangling 712100 PR.China Tangshan Teacher's College Tangshan 063000 P.R. China Tangshan Nanhu International Golf Club Tangshan 063000 P.R.China

The experiment aimed to evaluate the effects of N and trinexapac-ethyl （TE） to the growth of Kentucky bluegrass. By using the method of randomized blocks design, 4 N levels, 0 （N1）, 20 （N2）, 25 （N3）, and 30 （N4） kg N ha t mon% with TE at 0 （T1）, 312.5 （T2） and 625 （T3） mL ha-1 every 10 d effect on the total height, clippings and chlorophyll concentration of Kentucky bluegrass were evaluated. Results showed that total height and total clippings of Kentucky bluegrass were reduced by treating with TE and increased by treating with N. Kentucky bluegrass treated with 312.5 and 625 mL ha ＇ per 10 d had total clippings and total height reduced 30 and 45% under different N application level. The N × TE interaction was significant for the chlorophyll concentration of Kentucky bluegrass. The chlorophyll concentration of Kentucky bluegrass treated with TE at 625 mL ha-1 every 10 d was significantly higher than that of Kentucky bluegrass treated with 312.5 mL ha-1 every 10 d at the same N level. The chlorophyll concentration of turfgrass treated with TE at 625 mL ha-1 every 10 d receiving 30 kg N ha -1 month-1 was the highest. Based on the index of turf growth and the chlorophyll concentration, turfgrass receiving 20 or 30 kg N ha-1 month-1 with 625 mL TE ha i every 10 d could balance the problem of mowing frequency and growth quickly while keeping a good quality.

关键词： N fertilizer trinexapac-ethyl Kentucky bluegrass

Wideband spectrum sensing using step-sampling based on the multipath nyquist folding receiver

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Defence Technology（防务技术） 2024年第1期31卷 523-536页

作者： kai-lun tian kai-li Jiang Sen Cao Jian Gao Ying Xiong Bin Tang Xu-ying Zhang Yan-fei Li University of Electronic Science and Technology of China Chengdu611731China China Electronics Technology Group Corporation 29th Research Institute Chengdu610036China

Wideband spectrum sensing with a high-speed analog-digital converter(ADC) presents a challenge for practical *** Nyquist folding receiver(NYFR) is a promising scheme for achieving cost-effective real-time spectrum sensing,which is subject to the complexity of processing the modulated *** this case,a multipath NYFR architecture with a step-sampling rate for the different paths is *** different numbers of digital channels for each path are designed based on the Chinese remainder theorem(CRT).Then,the detectable frequency range is divided into multiple frequency grids,and the Nyquist zone(NZ) of the input can be obtained by sensing these ***,high-precision parameter estimation is performed by utilizing the NYFR *** with the existing methods,the scheme proposed in this paper overcomes the challenge of NZ estimation,information damage,many computations,low accuracy,and high false alarm *** simulation experiments verify the effectiveness of the proposed architecture in this paper.

关键词： Wideband spectrum sensing Sub-Nyquist sampling Step-sampling Nyquist folding receiver(NYFR) Multisignal processing