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Stahel-Donoho kernel estimation for fixed design nonparametric regression models

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Science China Mathematics 2006年第12期49卷 1879-1896页

作者： LIN lu cui xia School of Mathematics and System Sciences Shandong UniversityJi'nan 250100China School of Mathematics and System SciencesShandong UniversityJi'nan 250100China

This paper reports a robust kernel estimation for fixed design nonparametric regression models.A Stahel-Donoho kernel estimation is introduced,in which the weight functions depend on both the depths of data and the distances between the design points and the estimation *** on a local approximation,a computational technique is given to approximate to the incomputable depths of the *** a result the new estimator is computationally *** proposed estimator attains a high breakdown point and has perfect asymptotic behaviors such as the asymptotic normality and convergence in the mean squared *** the depth-weighted estimator for parametric regression models,this depth-weighted nonparametric estimator has a simple variance structure and then we can compare its efficiency with the original *** simulations show that the new method can smooth the regression estimation and achieve some desirable balances between robustness and efficiency.

关键词： nonparametric regression,kernel estimation,statistical depth,robustness.

Occurrence and possible sources of antibiotic resistance genes in seawater of the South China Sea

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Frontiers of Environmental Science & Engineering 2024年第9期18卷 27-38页

作者： Jian lu Jun Wu cui Zhang Jianhua Wang xia He CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone Research(YIC)Chinese Academy of Sciences(CAS)Shandong Key Laboratory of Coastal Environmental ProcessesYICCASYantai 264003China Yantai Research Institute Harbin Engineering UniversityYantai 264006China College of Environmental Science and Engineering Guilin University of TechnologyGuilin 541006China

Antibiotic resistance genes(ARGs)might have great effect on ecological security and human *** are important reservoirs that receive tremendous amounts of pollutants ***,information on the proliferation of ARGs in seawater is still *** study performed field sampling to investigate the occurrence and distribution of ARGs in seawater of the South China Sea,which is the deepest and largest sea in *** results showed that the total absolute abundances of ARGs in seawater samples ranged from 2.1×10^(3)to 2.3×10^(4)copies/mL,with an of 5.0×10^(3)copies/mL and a range of 2.2×10^(3)–1.8×10^(4)copies/mL for those with mobile genetic elements(MGEs).Genes resistant to multidrug,aminoglycoside,tetracycline,and fluoroquinolone antibiotics accounted for 77.3%–88.6%of total ARGs in *** and Cyanobacteria represented 32.1%–56.2%and 30.4%–49.5%of microbial community,***_MIT9313 and Clade_la were the prevalent genera in seawater of the South China *** co-occurrence relationship existed among ARGs,MGEs,and *** activities had critical influence on ARGs and *** wastewater,wastewater treatment plant effluent,sewage,aquaculture tailwater,and runoff were determined as the important sources of ARGs in seawater of the South China Sea based on positive matrix factorization analysis.

关键词： The South China Sea Antibiotic resistance genes Mobile genetic element Source apportionment

“Buckets effect”in the kinetics of electrocatalytic reactions

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Journal of Energy Chemistry 2024年第2期89卷 388-396,I0010页

作者： Haowen cui Yan-xia Chen Hefei National Laboratory for Physical Sciences at Microscale Department of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

In this study,we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction(ORR)on Pt(111)in acidic *** results demonstrate a rectangular hyperbolic relationship,i.e.,the ORR current excluding the effect of other variables increases with proton concentration and then tends to a constant *** consider that this is caused by the limitation of ORR kinetics by the trace oxygen concentration in the solution,which determines the upper limit of ORR kinetics.A model of effective concentration is further proposed for rectangular hyperbolic relationships:when the reactant concentration is high enough to reach a critical saturation concentration,the effective reactant concentration will become a constant *** could be due to the limited concentration of a certain reactant for reactions involving more than one reactant or the limited number of active sites available on the *** study provides new insights into the kinetics of electrocatalytic reactions,and it is important for the proper evaluation of catalyst activity and the study of structureperformance relationships.

关键词： Oxygen reduction reaction Kinetics Zero order Rectangular hyperbolic relationship pH effect

Deciphering the linear relationship in the activity of the oxygen reduction reaction on Pt electrodes:A decisive role of adsorbates

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Journal of Energy Chemistry 2024年第7期94卷 70-77页

作者： Haowen cui Yan-xia Chen Hefei National Research Center for Physical Sciences at Microscale and Department of Chemical Physics University of Science and Technology of ChinaHefei 230026AnhuiChina

Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte solution cannot be ***,we have systematically investigated the impact of adsorbate species and concentration,as well as solution pH,on the ORR activity on Pt(111)and Pt(poly)*** results all tend to establish a linear quantitative relationship between the onset potential for ORR and the adsorption equilibrium potential of the *** finding indicates the decisive role of adsorbates in the onset potential for ORR,suggesting that the adsorption potential of adsorbates can serve as an intuitive criterion for ORR *** support for this conclusion is derived from experimental results obtained from the oxygen evolution reaction on Pt(poly)with different adsorbate species and from the hydrogen evolution reaction on Pt(111)with iodine *** further propose both an empirical equation for the onset potential for ORR and the concept of a potential-regulated adsor-bate shielding effect to elucidate the influence of adsorbates on ORR *** study provides new insights into the high onset overpotential of the ORR and offers potential strategies for predicting and enhancingORRactivity inthefuture.

关键词： Oxygen reduction reaction Activity Adsorbate Equilibrium potential Pt(111)

Status and trends in the stability of the three largest ice shelves in Antarctica

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Science China Earth Sciences 2024年第8期67卷 2615-2632页

作者： Rongxing LI Guojun LI lu AN Menglian xia Da LV Yuan CHENG Aiguo ZHAO Tian CHANG xiangbin cui Shengkai ZHANG Shijie LIU Yixiang TIAN Weian WANG Center for Spatial Information Science and Sustainable Development Applications Tongji UniversityShanghai 200092China College of Surveying and Geo-informatics Tongji UniversityShanghai 200092China Postdoctoral Research Station of Shanghai Surveying and Mapping Institute Shanghai 200063China Key Laboratory of Spatial-temporal Big Data Analysis and Application of Natural Resources in Megacities Shanghai 200063China Institute for Conservation of Cultural Heritage School of Cultural Heritage and Information ManagementShanghai UniversityShanghai 200444China Polar Research Institute of China Shanghai 200136China Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China

The Ross,Filchner-Ronne,and Amery ice shelves are the three largest ice shelves in Antarctica,playing a crucial role in supporting the Antarctic ice ***,current studies on the stability of the three largest ice shelves primarily focus on singular or limited factors,lacking a comprehensive assessment of multiple *** systematically and in-depth study the stability and trend of the three largest ice shelves,we comprehensively collected and analyzed key parameters,including elevation changes,basal melting,surface meltwater,major rifts propagation rate,suture zones,ice front area change rate,grounding lines,ice velocity,and mass ***,we selected the collapsed Larsen B Ice Shelf(LBIS),the rapidly changing and structurally weakened Pine Island Ice Shelf(PIIS),and the accelerating Totten Ice Shelf(TIS)as reference ice *** comparing and analyzing the key parameters between these reference ice shelves and the three largest ice shelves,we find the status and trends in the stability of the *** findings reveal that most key parameters of the three largest ice shelves present relatively minor variations compared to those of the reference ice ***,50%of the parameters are smaller than those of the accelerating TIS,88%are smaller than those of the rapidly changing PIIS,and all parameters are smaller than those of the collapsed ***,after analyzing parameters that are not smaller than those of the TIS,it is observed that they remain in a stable ***,the three largest ice shelves are currently undergoing natural changes that do not threaten their stability in the short ***,the evolution of the ice shelves under global climate change remains uncertain,making long-term observation and monitoring essential to assess their impact on sea level rise.

关键词： Three largest ice shelves in Antarctica Key parameters Remote sensing monitoring Ice shelf stability Sea level change

Identification of lubricating Oil Additives Using XGBoost and Ant Colony Optimization Algorithms

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China Petroleum Processing & Petrochemical Technology 2024年第2期26卷 158-167页

作者： xia Yanqiu cui Jinwei Xie Peiyuan Zou Shaode Feng Xin School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing 102206China

To address the problem of identifying multiple types of additives in lubricating oil,a method based on midinfrared spectral band selection using the eXtreme Gradient Boosting(XGBoost)algorithm combined with the ant colony optimization(ACO)algorithm is *** XGBoost algorithm was used to train and test three additives,T534(alkyl diphenylamine),T308(isooctyl acid thiophospholipid octadecylamine),and T306(trimethylphenol phosphate),separately,in order to screen for the optimal combination of spectral bands for each *** ACO algorithm was used to optimize the parameters of the XGBoost algorithm to improve the identification *** this process,the support vector machine(SVM)and hybrid bat algorithms(HBA)were included as a comparison,generating four models:ACO-XGBoost,ACO-SVM,HBA-XGboost,and *** results showed that all four models could identify the three additives efficiently,with the ACO-XGBoost model achieving 100%recognition of all three *** addition,the generalizability of the ACO-XGBoost model was further demonstrated by predicting a lubricating oil containing the three additives prepared in our laboratory and a collected sample of commercial oil currently in use。

关键词： lubricant oil additives fourier transform infrared spectroscopy type identification ACO-XGBoost combinatorial algorithm

Identifying perforation locations for hydraulic fracturing treatment in deep and tight sandstone gas reservoirs

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Rock Mechanics Bulletin

Rock Mechanics Bulletin 2024年第3期3卷 14-23页

作者： Kaiming xia Weihua Wang Yufeng cui Saudi Aramco Dhahran 31311Eastern ProvinceSaudi Arabia AramcoAsia Beijing100004China

Fracture initiation has been a challenging issue for fracturing deep and tight gas reservoirs,which generally requires a high breakdown pressure for hydraulic fracturing *** this situation,fluid injections frequently have to terminate at the very *** predicting and solving this issue,a novel fracturing system for deep and tight sandstone gas reservoirs was *** key components of the fracturing system and some criterion will be introduced,which can be used to optimize the ideal perforation locations along the landing part and select the right perforation strategy *** main components of the fracturing system include:(1)evaluating the log-based diagenetic rock typing and flow index;(2)1D mechanical earth model;(3)calculating the breakdown pressure envelope along the well trajectory of the landing part;(4)calculating the optimal perforation directions along the landing part;(5)select the first set of perforation locations based on the log-based diagenetic rock typing and flow index;(6)narrowing down the first set of perforation locations to a second set of perforation locations based on the breakdown pressure envelope;(7)determining a perforation strategy based on breakdown pressure envelope and wellhead pressure safety limit in the second set of perforation *** computational framework to calculate the breakdown pressure envelope and optimal perforation directions is applicable to arbitrary well *** fracturing system has been used to provide pre-fracturing suggestions for wells landed in deep and tight sandstone reservoirs,which is very efficient for identifying locations with good rock typing and relatively low breakdown ***,it can indicate whether oriented perforation should be used further for alleviating breakdown *** taking these efforts and procedures,the fracturing success rate for deep and tight sandstone gas reservoirs can be improved,which has been verified in *** studi

关键词： reservoirs sandstone directions

Prediction model on hydrolysis kinetics of phthalate monoester:A density functional theory study

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Journal of Environmental Sciences 2024年第1期135卷 51-58页

作者： Tong Xu Jingwen Chen Deming xia Weihao Tang Jiansheng cui Chun Liu Shuangjiang Li College of Environmental Science and Engineering Hebei University of Science and TechnologyShijiazhuang 050000China Key Laboratory of Industrial Ecology and Environmental Engineering(Ministry of Education) School of Environmental Science and TechnologyDalian University of TechnologyDalian 116024China National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China

As primary degradation products of phthalate esters,phthalate monoesters(MPEs)have been widely detected in various aquatic environments and drawn growing toxicological *** kinetics that is of importance for assessing environmental persistence of chemicals remain elusive for ***,kinetics of base-catalyzed and neutral hydrolysis for 18 MPEs with different leaving groups was investigated by density functional theory *** indicate that MPEs with leaving groups having p Kaof<10 prefer dissociative transition *** are more persistent than their parents,and their hydrolysis half-lives were calculated to vary from 3.4 min to 79.2 years(p H=7–9).A quantitative structure-activity relationship model was developed for predicting the hydrolysis kinetics *** was found that p Kaof the leaving groups and electronegativity of the MPEs are key factors determining the hydrolysis *** work may lay a theoretical foundation for better understanding the chemical process that governs MPE persistence in aquatic environments.

关键词： Phthalate monoesters Phthalate esters Hydrolysis Density functional theory Quantitative structure-activity relationship

Wmic-GMTS and Wmic-GMERR criteria for micron-scale crack propagation in red-bed soft rocks under hydraulic action

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3641-3660页

作者： Guangjun cui Chunhui Lan cuiying Zhou Zhen Liu Chang xia Institute of Estuarine and Coastal Research School of Ocean Engineering and TechnologySun Yat-sen UniversityGuangzhou510275China Guangdong Provincial Engineering Research Center of Coasts Islands and ReefsSun Yat-sen UniversityGuangzhou510275China Guangdong Engineering Research Center for Major Infrastructure Safety Sun Yat-sen UniversityGuangzhou510275China The Hong Kong Polytechnic University Hong KongChina

Micron-scale crack propagation in red-bed soft rocks under hydraulic action is a common cause of engineering disasters due to damage to the hard rockesoft rockewater *** studies have not provided a theoretical analysis of the length,inclination angle,and propagation angle of micron-scale cracks,nor have they established appropriate criteria to describe the crack propagation *** propagation mechanism of micron-scale cracks in red-bed soft rocks under hydraulic action is not yet fully understood,which makes it challenging to prevent engineering disasters in these types of *** address this issue,we have used the existing generalized maximum tangential stress(GMTS)and generalized maximum energy release rate(GMERR)criteria as the basis and introduced parameters related to micron-scale crack propagation and water *** GMTS and GMERR criteria for micronscale crack propagation in red-bed soft rocks under hydraulic action(abbreviated as the Wmic-GMTS and Wmic-GMERR criteria,respectively)were established to evaluate micron-scale crack propagation in redbed soft rocks under hydraulic *** influence of the parameters was also *** process of micron-scale crack propagation under hydraulic action was monitored using uniaxial compression tests(UCTs)based on digital image correlation(DIC)*** study analyzed the length,propagation and inclination angles,and mechanical parameters of micron-scale crack propagation to confirm the reliability of the established *** findings suggest that the Wmic-GMTS and Wmic-GMERR criteria are effective in describing the micron-scale crack propagation in red-bed soft rocks under hydraulic *** study discusses the mechanism of micron-scale crack propagation and its effect on engineering disasters under hydraulic *** covers topics such as the internal-external weakening of nano-scale particles,lateral propagation of micron-scale cracks,weakening of the mechanical properties

关键词： Red-bed soft rocks Hydraulic action Micron-scale cracks Generalized maximum tangential stress (GMTS)criterion Generalized maximum energy release rate (GMERR)criterion Digital image correlation(DIC)