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A four-band index for both liquid and solid water and its applications in the Aral Sea Basin

Science China Earth Sciences 2024年第3期67卷 769-788页

作者： Bing YUE Xi CHEN Saibo LI zhengping du John WILSON Junhui YANG Yimen JIAO Shuangyan HUANG Chenghu ZHOU Xinjiang Institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Institute of Geographical Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Spatial Sciences Institute University of Southern CaliforniaLos AngelesCA 90089-0374USA

Various investigations have been conducted to analyze the water-coverage area of the Aral Sea and the Aral Sea Basin(ASB). However, the investigations incorporated considerable uncertainty and the used water indices had misclassification problem, which made different research groups present different results. Thus we first ascertain the boundaries of the ASB, the Syr and Amu river basins as well as their upper, middle and lower reaches. Then a four-band index for both liquid and solid water(ILSW) is proposed to address the misclassification problems of the classic water indices. ILSW is calculated by using the reflectance values of the green, red, near infrared, and thermal infrared bands, which combines the normalized difference water index(NDWI) and land surface temperature(LST) together. Validation results show that the ILSW water index has the highest accuracy by far in the Aral Sea Basin. Our results indicate that annual average decline of the water-coverage area was 963 km^(2) in the southern Aral Sea, whereas the northern Aral Sea has experienced little change. In the meanwhile, permanent ice and snow in upper reach of ASB has retreated considerably. Annual retreating rates of the permanent ice and snow were respectively 6233and 3841 km^(2) in upper reaches of Amu river basin(UARB) and Syr river basin(USRB). One of major reasons is that climate has become warmer in ASB. The climate change has caused serious water deficit problem. The water deficit had an increasing trend since the 1990s and its increasing rates was 3.778 billion m^(3) yearly on average. The total water deficit was 76.967 billion m^(3) on average in the whole area of ASB in the 2010s. However, up reaches of Syr river basin(USRB), a component area of ASB, had water surplus of 25.461 billion m^(3). These conclusions are useful for setting out a sustainable development strategy in ASB.

关键词： Aral Sea Basin Syr river basin Amu river basin Water indices Water-coverage area Water deficit Climate change

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An improved HASM method for dealing with large spatial data sets

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Science China Earth Sciences 2018年第8期61卷 1078-1087页

作者： Na ZHAO Tianxiang YUE Chuanfa CHEN Miaomiao ZHAO zhengping du State Key Laboratory of Resources and Environment Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Jiangsu Center for Collaborative Innovation in Geographic Information Resource Development and Application Nanjing 210023 China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100101 China Geomatics College Shandong University of Science and Technology Qingdao 266510 China

Surface modeling with very large data sets is challenging. An efficient method for modeling massive data sets using the high accuracy surface modeling method(HASM) is proposed, and HASM_Big is developed to handle very large data sets. A large data set is defined here as a large spatial domain with high resolution leading to a linear equation with matrix dimensions of hundreds of thousands. An augmented system approach is employed to solve the equality-constrained least squares problem(LSE) produced in HASM_Big, and a block row action method is applied to solve the corresponding very large matrix equations.A matrix partitioning method is used to avoid information redundancy among each block and thereby accelerate the *** including numerical tests and real-world applications are used to compare the performances of HASM_Big with its previous version, HASM. Results show that the memory storage and computing speed of HASM_Big are better than those of HASM. It is found that the computational cost of HASM_Big is linearly scalable, even with massive data sets. In conclusion,HASM_Big provides a powerful tool for surface modeling, especially when there are millions or more computing grid cells.

关键词： Surface modeling HASM Large spatial data

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Sensitivity studies of a high accuracy surface modeling method

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Science China Earth Sciences 2014年第10期57卷 2386-2396页

作者： ZHAO Na YUE TianXiang ZHAO MingWei du zhengping FAN ZeMeng CHEN ChuanFa State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Geomatics College Shandong University of Science and Technology

The sensitivities of the initial value and the sampling information to the accuracy of a high accuracy surface modeling(HASM) are investigated and the implementations of this new modeling method are modified and enhanced. Based on the fundamental theorem of surface theory, HASM is developed to correct the error produced in geographical information system and ecological modeling process. However, the earlier version of HASM is theoretically incomplete and its initial value must be produced by other surface modeling methods, such as spline, which limit its promotion. In other words, we must use other interpolators to drive HASM. According to the fundamental theorem of surface theory, we modify HASM, namely ***, by adding another important nonlinear equation to make it independent of other methods and, at the same time, have a complete and solid theory foundation. Two mathematic surfaces and monthly mean temperature of 1951–2010 are used to validate the effectiveness of the new method. Experiments show that the modified version of HASM is insensitive to the selection of initial value which is particular important for HASM. We analyze the sensitivities of sampling error and sampling ratio to the simulation accuracy of ***. It is found that sampling information plays an important role in the simulation accuracy of ***. Another feature of the modified version of HASM is that it is theoretically perfect as it considers the third equation of the surface theory which reflects the local warping of the surface. The modified HASM may be useful with a wide range of spatial interpolation as it would no longer rely on other interpolation methods.

关键词： HASM spatial interpolation initial value sensitivity accuracy temperature

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Nonlinear uncertainty impact of geometric variations on aerodynamic performance of low-pressure turbine blades with ultra-high loading under extreme operational conditions

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Chinese Journal of Aeronautics 2024年第5期37卷 281-300页

作者： Xiaojing WANG zhengping ZOU Chao FU Pengcheng du School of Energy and Power Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

Uncertainty impact of random geometric variations on the aerodynamic performance of low-pressure turbine blades is considerable,which is further amplified by the current ultra-high-lift design trend for weight ***,this uncertainty impact on ultra-highly loaded blades under extreme operational conditions near the margins with potential large-scale open separation is focused on in this *** is demonstrated that this impact is significant,unfavourable,and nonlinear,which is clearly severer under extreme *** addition to the overall attenuation and notable scattering of specific performance,the operational margins with open separation are also notably scattered with great risk of significant *** scattering and nonlinearity are dominated by the variations in leading-edge *** thinning of leading edge triggers local transition,enhancing downstream friction and reducing resistance to open separation,which is further exacerbated by operational ***,the opposite thickening yields less benefit,implying *** unfavourable impact highlights the need for robust aerodynamic design,where both a safer operational condition and a more robust blade are indispensable,i.e.,a compromise among performance,weight,and *** the necessary limitation of loading levels,a mid-loaded design is recommended to reduce adverse pressure gradients in both the leading edge and rear region of the suction side,which helps to decrease the susceptibility of the transition and open separation to random *** improvements can also be achieved by appropriately thickening the leading edge.

关键词： Ultra-highly loaded turbine blade Geometric variations Uncertainty analysis Operational margins Robust aerodynamic design Nonlinearity

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HASM quantum machine learning

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Science China Earth Sciences 2023年第9期66卷 1937-1945页

作者： Tianxiang YUE Chenchen WU Yi LIU zhengping du Na ZHAO Yimeng JIAO Zhe XU Wenjiao SHI State Key Laboratory of Resources and Environment Information System Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Yanqi Lake Beijing Institute of Mathematical Sciences and Applications Beijing 101408China College of Resources and Environment University of Chinese Academy of SciencesBeijing 101499China College of Land Resources and Environment Jiangxi Agricultural UniversityNanchang 330045China

The miniaturization of transistors led to advances in computers mainly to speed up their *** miniaturization has approached its fundamental ***,many practices require better computational resources than the capabilities of existing ***,the development of quantum computing brings light to solve this *** briefly review the history of quantum computing and highlight some of its advanced *** on current studies,the Quantum Computing Advantage(QCA)seems *** challenge is how to actualize the practical quantum advantage(PQA).It is clear that machine learning can help with this *** method used for high accuracy surface modelling(HASM)incorporates reinforced machine *** can be transformed into a large sparse linear system and combined with the Harrow-Hassidim-Lloyd(HHL)quantum algorithm to support quantum machine *** has been successfully used with classical computers to conduct spatial interpolation,upscaling,downscaling,data fusion and model-data assimilation of ecoenvironmental ***,a training experiment on a supercomputer indicates that our HASM-HHL quantum computing approach has a similar accuracy to classical HASM and can realize exponential acceleration over the classical algorithms.A universal platform for hybrid classical-quantum computing would be an obvious next step along with further work to improve the approach because of the many known limitations of the HHL *** addition,HASM quantum machine learning might be improved by:(1)considerably reducing the number of gates required for operating HASM-HHL;(2)evaluating cost and benchmark problems of quantum machine learning;(3)comparing the performance of the quantum and classical algorithms to clarify their advantages and disadvantages in terms of accuracy and computational speed;and(4)the algorithms would be added to a cloud platform to support applications and gather active feedback from users

关键词： Quantum computing Machine learning Eco-environmental surface High accuracy surface modelling Quantum computational advantage Practical quantum advantage

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Insights into thermodynamic performance of a hypersonic precooled air-breathing engine with a complicated multi-branch closed cycle

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Chinese Journal of Aeronautics 2024年第8期37卷 106-123页

作者： Yifan WANG zhengping ZOU Pengcheng du Lichao YAO Huoxing LIU Yusen XU Research Institute of Aero-Engine Beihang UniversityBeijing 102206China National Key Laboratory of Science and Technology on Aero-Engine and Aero-Thermodynamics Beihang UniversityBeijing 102206China

An advanced precooled airbreathing engine with a closed Brayton cycle is a promising solution for high-speed propulsion,of which the Synergetic Air Breathing Rocket Engine(SABRE)is a representative *** performance of the latest SABRE-4 cycle was analyzed in this ***,a relatively complete engine performance model that considers the characteristics of turbomachinery and heat exchangers was ***,Sobol’global sensitivity analysis of key performance parameters was carried out to identify the most influential design *** specific impulses under different target specific thrusts were obtained by particle swarm optimization,of which the thermodynamic parameters corresponding to a specific thrust of 1.12 kN·s·kg^(-1)and a specific impulse of 3163 s were chosen as the design *** different control laws were analyzed in contrast,and the charge control method had the strongest ability of thrust regulation as well as maintaining a favorable specific impulse ***,working characteristics under the charge control and over a typical flight envelope were calculated,in which the average value of the maximum specific impulse was as high as 5315 *** study would help to deepen the understanding of SABRE-4 thermodynamic characteristics and other precooled airbreathing engine cycles with similar layouts.

关键词： Hypersonic Precooled airbreathing engine Thermodynamic cycle Control law Working characteristics

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Development of a surface modeling method for mapping soil properties

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Journal of Geographical Sciences 2012年第4期22卷 752-760页

作者： SHI Wenjiao LIU Jiyuan du zhengping YUE Tianxiang Institute of Geographic Sciences and Natural Resources Research CASBeijing 100101China

High accuracy surface modeling （HASM） is a method which can be applied to soil property interpolation. In this paper, we present a method of HASM combined geographic information for soil property interpolation （HASM-SP） to improve the accuracy. Based on soil types, land use types and parent rocks, HASM-SP was applied to interpolate soil available P, Li, pH, alkali-hydrolyzable N, total K and Cr in a typical red soil hilly region. To evaluate the performance of HASM-SP, we compared its performance with that of ordinary kriging （OK）, ordinary kriging combined geographic information （OK-Geo） and stratified kriging （SK）. The results showed that the methods combined with geographic information including HASM-SP and OK-Geo obtained a lower estimation bias. HASM-SP also showed less MAEs and RMSEs when it was compared with the other three methods （OK-Geo, OK and SK）. Much more details were presented in the HASM-SP maps for soil properties due to the combination of different types of geographic information which gave abrupt boundary for the spatial varia- tion of soil properties. Therefore, HASM-SP can not only reduce prediction errors but also can be accordant with the distribution of geographic information, which make the spatial simula- tion of soil property more reasonable. HASM-SP has not only enriched the theory of high accuracy surface modeling of soil property, but also provided a scientific method for the ap- plication in resource management and environment planning.

关键词： high accuracy surface modeling (HASM) spatial interpolation accuracy geostatistics soil properties red soil hilly legion in South China

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Dark Localized Waves in Shallow Waters:Analysis within an Extended Boussinesq System

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Chinese Physics Letters 2024年第4期41卷 32-37页

作者： zhengping Yang Wei-Ping Zhong Milivoj Belic Department of Medical Science Shunde PolytechnicShunde 528300China Department of Electronic Engineering Shunde PolytechnicShunde 528300China Division of Arts and Sciences Texas A&M University at Qatar23874 DohaQatar

We study dark localized waves within a nonlinear system based on the Boussinesq approximation,describing the dynamics of shallow water *** symbolic calculus,we apply the Hirota bilinear method to transform an extended Boussinesq system into a bilinear form,and then use the multiple rogue wave method to obtain its dark rational *** the first-and second-order dark solutions,we examine the conditions under which these localized solutions exist and their spatiotemporal *** the selection of various parameters and by utilizing different visualization techniques(intensity distributions and contour plots),we explore the dynamical properties of dark solutions found:in particular,the first-and second-order dark rogue *** also explore the methods of their *** findings presented here not only deepen the understanding of physical phenomena described by the(1+1)-dimensional Boussinesq equation,but also expand avenues for further *** method can be extended to other nonlinear systems,to conceivably obtain higher-order dark rogue waves.

关键词： Boussinesq bilinear nonlinear

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Compound Product of Hypermatrices

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Journal of Systems Science & Complexity 2024年第1期37卷 169-183页

作者： CHENG Daizhan MENG Min ZHANG Xiao JI zhengping Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China Department of Control Science and Engineering School of Electronics and Information EngineeringTongji UniversityShanghai 201210China National Center for Mathematics and Interdisciplinary Sciences Chinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100149China.

The semi-tensor product(STP)of matrices is generalized to multidimensional arrays,called the compound product of *** product is first defined for three-dimensional hypermatrices with compatible orders and then extended to general *** different types of hyperdeterminants are introduced and certain properties are *** Lie groups and Lie algebras corresponding to the hypermatrix products are ***,these results are applied to dynamical systems.

关键词： Compound semi-tensor product hyperdeterminants hypereigenvalues and hypereigenvectors hypergeneral linear groups hypermatrices.

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Role of A-sites in pyrochlore lanthanide ruthenate for electrocatalysis of oxygen evolution reaction

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Journal of Materiomics 2024年第6期10卷 1234-1242页

作者： Hengyu Guo zhengping Zhang Feng Wang State Key Laboratory of Chemical Resource Engineering Beijing Key Laboratory of Electrochemical Process and Technology for MaterialsBeijing University of Chemical TechnologyBeijing100029China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing100029China

Developing highly stable and efficient catalysts for oxygen evolution reaction(OER)is extremely important to sustainable energy conversion and storage,but improved efficiency is largely hindered by sluggish reaction *** and bimetal ruthenates have emerged as one of the promising substitutes to replace single-metal ruthenium or iridium oxides,but the fundamental understanding the role of A-site cations is still ***,a family of lanthanides(Ln=all the lanthanides except Pm)are applied to synthesize pyrochlore lanthanide ruthenates(Ln_(2)Ru_(2)O_(7)),and only Ln_(2)Ru_(2)O_(7)(Ln=Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,or Lu)with pure phase can be obtained by the ambient-pressure *** with the perovskite ruthenates(SrRuO_(3))and rutile RuO_(2),the[RuO_(6)]units in these Ln_(2)Ru_(2)O_(7) present the largely distorted configurations and different energy level splitting to prevent the excessive Ru oxidation and dissolution,which leads the primary improvement in the electrocatalytic OER *** the similar crystalline field split states,the charge transfer between[RuO6]units and Ln^(3+)cations also affect catalytic activities,even in the Ln_(2)Ru_(2)O_(7) surface reconstruction during the OER ***,Tb_(2)Ru_(2)O_(7) showed the highest OER performance among all the prepared Ln_(2)Ru_(2)O_(7) with similar morphologies and *** systematic work gives fundamental cognition to rational design of high-performance OER electrocatalysts in proper water electrolysis technologies.

关键词： Pyrochlores Lanthanides Ruthenates Electrocatalysts Oxygen evolution reaction

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