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Robust Interval State Estimation for Distribution Systems Considering Pseudo-measurement Interval Prediction

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 179-188页

作者： xu Zhang wei Yan Meiqing Huo Hui Li the School of Electrical Engineering Chongqing UniversityChongqing 400044China

Interval state estimation(ISE)can estimate state intervals of power systems according to confidence intervals of predicted pseudo-measurements,thereby analyzing the impact of uncertain pseudo-measurements on ***,predicted pseudo-measurements have prediction errors,and their confidence intervals do not necessarily contain the truth values,leading to estimation biases of the *** solve this problem,this paper proposes a pseudo-measurement interval prediction framework based on the Gaussian process regression(GPR)model,thereby improving the prediction accuracy of pseudo-measurement confidence ***,a weight assignment strategy for improving the robustness of weighted least squares(WLS)ISE is *** strategy quantifies the deviation between the pseudo-measurement intervals and their estimated intervals and assigns smaller weights to the pseudo-measurement intervals with larger deviations,thereby improving the estimation accuracy and robustness of the *** paper adopts the data from the supervisory control and data acquisition(SCADA)system of the New York Independent System Operator(NYISO).It verifies the advantages of the GPR method for pseudo-measurement interval prediction by comparing it with the quantile regression and neural network *** addition,this paper demonstrates the effectiveness of the proposed weight assignment strategy through the IEEE 14-bus ***,the differences in the estimation accuracy and the bad data identification between the robust interval state estimation and deterministic state estimation are discussed.

关键词： Interval state estimation interval analysis pseudo-measurement Gaussian process regression(GPR)

Neural network based adaptive nonsingular practical predefined-time fault-tolerant control for hypersonic morphing aircraft

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Chinese Journal of Aeronautics 2024年第4期37卷 421-435页

作者： Shihao xu Changzhu wei Litao ZHANG Rongjun MU School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing Institute of Control&Electronics Technology Beijing 100038China

This paper develops a novel Neural Network(NN)-based adaptive nonsingular practical predefined-time controller for the hypersonic morphing aircraft subject to actuator faults. Firstly, a novel Lyapunov criterion of practical predefined-time stability is established. Following the proposed criterion, a tangent function based nonsingular predefined-time sliding manifold and the control strategy are developed. Secondly, the radial basis function NN with a low-complexity adaptation mechanism is incorporated into the controller to tackle the actuator faults and uncertainties. Thirdly, rigorous theoretical proof reveals that the attitude tracking errors can converge to a small region around the origin within a predefined time, while all signals in the closed-loop system remain bounded. Finally, numerical simulation results are presented to verify the effectiveness and improved performance of the proposed control scheme.

关键词： Hypersonic morphing aircraft(HMA) Neural network(NN) Adaptive control Practical predefined-time control Fault-tolerant control

Origin of condensate oil and natural gas in Bozhong 19-6 gas field,Bohai Bay Basin

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Energy Geoscience 2024年第1期5卷 54-62页

作者： Jianyong xu wei Li CNOOC Research Institute Co.Ltd. Beijing100028China

The discovery of the Bozhong 19-6 gas field has opened a new frontier for deep gas exploration in the Bohai Bay Basin,with a great potential for further gas ***,poor understanding of oil and gas origin has been limiting the exploration progress in this *** clarify the origin of condensate oil and gas in Bozhong 19-6 gas field,this study adequately utilized the organic geochemical analysis data to investigate the composition and geochemical characteristics of condensate oil and natural gas,and analyzed the relationship between condensate oil and the three sets of source rocks in the nearby *** show that the lighter components dominate the condensate oil,with a forward type *** parent material of crude oil was primarily deposited in a shallow,clay-rich,low-salinity,weakly reducing aquatic *** condensate and natural gas have similar parent source characteristics and maturity,with Ro ranging from 1.4%to 1.6%.Both are products of high maturity stage,indicating that they are hydrocarbon compounds produced by the same group of source rocks in the same ***-sources correlation shows that condensate oil and gas mainly originate from the source rocks of the third member of Shahejie Formation in the nearby subsags of the Bozhong 19-6 structural belt.

关键词： Bozhong Sag Natural gas Condensate oil Light hydrocarbon Gas-source correlation Oil-source correlation

AERATION EFFECT OF SUBMERGED JET ON HYDRAULIC CHARACTERISTICS

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Journal of Hydrodynamics 2002年第3期14卷 35-39页

作者： Liu, Shan-Jun xu, wei-lin Wang, wei Qu, Jing-xue Hydraulics Lab. of High Speed Flows Sichuan Univ. Chengdu 610065 China

A water-air two-phase turbulence mathematical model was proposed, The mass-weighted average was adopted for velocity, air mass fraction and turbulent parameters. The algebraic stress equation was used to calculate the Reynolds stress. The pulsating flux of air mass fraction was simulated by employing the concept of the eddy viscosity. The numerical simulation of aerated flow in plunge pool shows that, for the same depth, aeration may decrease the time-averaged pressure on pool floor and increase slightly the turbulent intensity. The computed concentration and pressure distributions coincide with the experimental data.

关键词： Computer simulation Mathematical models Pressure distribution Turbulent flow Two phase flow

On-surface synthesis and characterization of polyynic carbon chains

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National Science Review 2024年第3期11卷 192-199页

作者： Wenze Gao wei Zheng Luye Sun Faming Kang Zheng Zhou wei xu Interdisciplinary Materials Research Center School of Materials Science and Engineering Tongji University

Carbyne, an elusive sp-hybridized linear carbon allotrope, has fascinated chemists and physicists for decades. Due to its high chemical reactivity and extreme instability, carbyne was much less explored in contrast to the sp2-hybridized carbon allotropes such as graphene. Herein, we report the on-surface synthesis of polyynic carbon chains by demetallization of organometallic polyynes on the Au（111） surface;the longest one observed consists of ～60 alkyne units（120 carbon atoms）. The polyynic structure of carbon chains with alternating triple and single bonds was unambiguously revealed by bond-resolved atomic force microscopy. Moreover, an atomically precise polyyne, C14, was successfully produced via tip-induced dehalogenation and ring-opening of the decachloroanthracene molecule(C14Cl10) on a bilayer NaCl/Au（111） surface at 4.7 K, and a band gap of 5.8 eV was measured by scanning tunnelling spectroscopy,in a good agreement with the theoretical HOMO–LUMO gap（5.48 eV）.

关键词： polyyne scanning probe microscopy carbon allotrope on-surface synthesis organometallic polyyne

An Efficient Local Radial Basis Function Method for Image Segmentation Based on the Chan-Vese Model

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 1119-1134页

作者： Shupeng Qiu Chujin lin wei Zhao School of Mathematics and Statistics Guangdong University of TechnologyGuangzhou510520China

In this paper,we consider the Chan–Vese(C-V)model for image segmentation and obtain its numerical solution accurately and *** this purpose,we present a local radial basis function method based on a Gaussian kernel(GA-LRBF)for spatial *** to the standard radial basis functionmethod,this approach consumes less CPU time and maintains good stability because it uses only a small subset of points in the whole computational ***,since the Gaussian function has the property of dimensional separation,the GA-LRBF method is suitable for dealing with isotropic ***,a numerical scheme that couples GA-LRBF with the fourth-order Runge–Kutta method is applied to the C-V model,and a comparison of some numerical results demonstrates that this scheme achieves much more reliable image segmentation.

关键词： Image segmentation Chan–Vese model local radial basis functionmethod Gaussian kernel Runge–Kuttamethod

CdS/LaFeO_(3) heterojunctions with improved optical properties for visible-light catalytic applications

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Journal of Rare Earths 2024年第5期42卷 879-888,I0003页

作者： Jiaqi wei Wen Zhu xuelian xu Xiao xu Junjiang Zhu Hubei Key Laboratory of Biomass Fibers and Eco-dyeing&Finishing College of Chemistry and Chemical EngineeringWuhan Textile University ChemistryWuhan430200China

Construction of heterojunctions is a normal and effective strategy to improve the photocatalytic performances of semiconductors,through which both the lifetime and the redox ability of electrons/holes can be improved,as co mpared to the respective *** this basis,we constructed Z-scheme CdS/LaFeO_(3) heterojunctions(CdS/LFO),by in-situ growing different amounts of CdS on the surface of LaFeO_(3),for photocatalytic degradation of tetracycline hydrochloride(TC)in aqueous solution at room *** crystal structure,surface morphology and optoelectronic properties of the COS/LFO heterojunctions were systemically characterized to correlate the reaction *** tests indicate that the CdS/LFO heterojunctions exhibit promising activity for TC degradation under visible light irradiation(λ≥420 nm),with 85%TC conversion obtained at reaction time of 45 min,which is 3.4 and 1.9 times higher than that of CdS and LaFeO_(3).The CdS/LFO heterojunctions are also stable in the reaction and can be reused for four cycles with no appreciable activity *** applicability of CdS/LFO to photocatalytic degradation of organic dyes,as well as the reaction mechanism,was also explored.

关键词： LaFeO_(3) CdS Photocatalytic degradation Tetracycline hydrochloride Reaction mechanism Rare earths

Transverse mode-coupling instability with longitudinal impedance

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Nuclear Science and Techniques 2024年第6期35卷 40-53页

作者： Hai-Sheng xu Chun-Tao lin Na Wang Jing-Ye xu Yuan Zhang Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Institute of Advanced Science Facilities Shenzhen 518107GuangdongChina

Transverse mode-coupling instability(TMCI)is a dangerous transverse single-bunch instability that can lead to severe par-ticle *** mechanism of TMCI can be explained by the coupling of transverse coherent oscillation modes owing to the transverse short-range wakefield(i.e.,the transverse broadband impedance).Recent studies on future circular colliders,e.g.,FCC-ee,showed that the threshold of TMCI decreased significantly when both longitudinal and transverse impedances were *** performed computations for the circular electron-positron collider(CEPC)and observed a similar *** studies on the influence of longitudinal impedance on the TMCI threshold were *** concluded that the imaginary part of the longitudinal impedance,which caused a reduction in the incoherent synchrotron tune,was the primary reason for the reduction in the TMCI ***,the real part of the longitudinal impedance assists in increasing the TMCI threshold.

关键词： Transverse mode-coupling instability Longitudinal impedance

Evaluation of suitability,adaptability,and reserve potential of construction land on the Qinghai-Tibet Plateau

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Journal of Geographical Sciences 2024年第1期34卷 41-61页

作者： YANG Hua xu Yong ZHOU Kan WANG Lijia xu lin Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Construction land is the leading carrier of human activities such as production and *** the construction land suitability(CLS)on the Qinghai-Tibet Plateau(QTP)holds significant implications for harmonizing the relationship between ecological protection and human activity and promoting population and industry layout ***,no relevant studies provide a complete CLS assessment of the *** this study,we developed a model-based CLS evaluation framework coupling of pattern and process to calculate the global CLS on the QTP based on a previously developed CLS evaluation ***,using the land-use data of 1990,2000,2010,and 2020,we examined the adaptability of existing construction land(ECL)to the CLS assessment result through the adaptability index and vertical gradient index and further analyzed the limitations of maladaptive construction ***,we calculated the potential area of reserve suitable construction *** article includes four conclusions:(1)The highly suitable,suitable,moderately suitable,marginally suitable,and unsuitable CLS classes cover areas of 0.33×10^(4)km^(2),10.42×10^(4)km^(2),18.06×10^(4)km^(2),24.12×10^(4)km^(2),and 205.29×10^(4)km^(2),*** approximately 11%of the study area on the QTP is suitable for large-scale permanent construction land,and approximately 79.50%of the area is unsuitable under current economic and technological conditions.(2)The ECL adaptability index is 85.16%,85.93%,85.18%,and 78.01%during 1990–2020,respectively,with an average adaptability index exceeding 80%on the *** ECL distribution generally conforms to construction land suitable space characteristics but with a significant spatial difference.(3)From 1990 to 2020,the maladaptive ECL was dominated by rural settlement land,transport land,and special land,with a rapidly increasing proportion of urban and other construction *** maladaptive ECL is constrained by both elevation and slope in the southern Qinghai Pla

关键词： land resource construction land suitability existing construction land adaptability human activity Qinghai-Tibet Plateau