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Red/NIR/SWIR multi-band persistent luminescent nanoparticles as ultrasensitive multi-channel tracers in water and crude oil/water emulsions

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Nano Research 2023年第11期16卷 12706-12712页

作者： Yafei Chen Zhengwei pan Center for Integrative Petroleum Research College of Petroleum Engineering and GeosciencesKing Fahd University of Petroleum and MineralsDhahran 31261Saudi Arabia

We report the use of CaTiO_(3):Pr^(3+)multiband persistent luminescent nanoparticles,which can simultaneously emit red(610 nm),near-infrared(893 nm),and short-wave infrared(1040 nm)photoluminescence and persistent luminescence,as the tracer nanoagents for water tracer *** using a spectrofluorometer,an Si charge-coupled device(CCD)camera and an InGaAs array camera as the detection tools,we evaluated the sensing capabilities of the three emission bands of CaTiO_(3):Pr^(3+)nanoparticles in brine water solutions and crude oil/brine water emulsions in both photoluminescence mode and persistent luminescence *** these different detection combinations,the persistent luminescence-based Si CCD camera imaging exhibits the best sensing performance with the detection limits being at a single-digit ppb level for the 610 and 893 nm bands and about 100–200 ppb for the 1040 nm band in both water solutions and crude oil/water emulsions,while the photoluminescencebased Si CCD camera imaging has a much higher detection limit of~10 ppm in water solutions and of~200 ppm in oil/water *** persistent luminescence-based InGaAs array camera imaging to the 1040 nm band has the worst performance with the detection limits higher than 200 ppm for both *** sensing performances of the spectrofluorometer to photoluminescence signals and persistent luminescence signals in the two solutions are about the same,with the detection limits being around 100–200 ppm.

关键词： water tracer CaTiO_(3):Pr^(3+)nanoparticles photoluminescence persistent luminescence crude oil/water emulsion detection limit

Third-order unconditional positivity-preserving schemes for reactive flows keeping both mass and mole balance

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Chinese Journal of Aeronautics 2023年第11期36卷 24-41页

作者： Jianhua pan Luxin Li Zhejiang Provincial Engineering Research Center for the Safety of Pressure Vessel and Pipeline Ningbo UniversityNingbo 315211China Key Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo 315211China

In this paper,the previously proposed second-order process-based modified Patankar Runge-Kutta schemes are extended to the third order of *** to the process-based implicit handling of reactive source terms,the mass conservation,mole balance and energy conservation are kept simultaneously while the positivity for the density and pressure is preserved unconditionally even with stiff reaction *** is proved that the first-order truncation terms for the Patankar coefficients must be zero to achieve a prior third order of accuracy for most cases.A twostage Patankar procedure for each Runge-Kutta step is designed to eliminate the first-order truncation terms,accomplish the prior third order of accuracy and maximize the Courant number which the total variational diminishing property *** the same approach as the second-order schemes,the third-order ones are applied to Euler equations with chemical reactive source *** studies including both 1D and 2D ordinary and partial differential equations are conducted to affirm both the prior order of accuracy and the positivity-preserving property for the density and pressure.

关键词： Chemical reactions Positivity-preserving Patankar schemes Mass conservation Mole balance Third-order schemes

Lightweight privacy-preserving truth discovery for vehicular air quality monitoring

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Digital Communications and Networks 2023年第1期9卷 280-291页

作者： Rui Liu Jianping pan Department of Computer Science University of VictoriaVictoriaBCV8P 5C2Canada

Air pollution has become a global concern for many *** crowdsensing systems make it possible to monitor air quality at a fine *** better utilize the sensory data with varying credibility,truth discovery frameworks are ***,in urban cities,there is a significant difference in traffic volumes of streets or blocks,which leads to a data sparsity problem for truth *** the privacy of participant vehicles is also a crucial *** first present a data masking-based privacy-preserving truth discovery framework,which incorporates spatial and temporal correlations to solve the sparsity *** further improve the truth discovery performance of the presented framework,an enhanced version is proposed with anonymous communication and data *** frameworks are more lightweight than the existing cryptography-based *** also evaluate the work with simulations and fully discuss the performance and possible extensions.

关键词： Privacy preserving Truth discovery Crowdsensing Vehicular networks

Siegmund Duality for Continuous Time Markov Chains on Z_+~d

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Acta Mathematica Sinica,English Series 2018年第9期34卷 1460-1472页

作者： pan ZHAO Department of Basic Courses Beijing Union University

For the continuous time Markov chain with transition function P（t） on Z d ＋ , we give the necessary and sufficient conditions for the existence of its Siegmund dual with transition function P - （t）. If Q, the q-matrix of P（t）, is uniformly bounded, we show that the Siegmund dual relation can be expressed directly in terms of q-matrices, and a sufficient condition under which the Q-function is the Siegnmnd dual of some Q-function is also given.

关键词： Continuous time Markov chains the Siegmund dual Mobius function ↑-Mobius mono-tonicity Feller Reuter Riley transition functions birth and death chains

Bayesian optimization+XGBoost based life cycle carbon emission prediction for residential buildings—An example from Chengdu,China

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Building Simulation 2023年第8期16卷 1451-1466页

作者： Haize pan Chengjin Wu School of Civil Engineering and Geomatics Southwest Petroleum UniversityChengdu 610500China

The large amount of carbon emissions generated by buildings during their life cycle greatly impacts the environment and poses a considerable challenge to China’s carbon reduction *** building design phase has the most significant potential to reduce building life-cycle carbon emissions(LCCO_(2)).However,the lack of detailed inventory data at the design stage makes calculating a building’s LCCO_(2) very difficult and ***,accurate prediction of building LCCO_(2) at the design stage using relevant design factors is essential to reduce carbon *** paper proposes an ensemble learning algorithm combining Bayesian optimization and extreme gradient boosting(BO-XGBoost)to predict LCCO_(2) accurately in residential ***,this study collected and calculated the LCCO_(2) of 121 residential buildings in Chengdu,***,a carbon emission prediction model was developed using XGBoost based on 15 design factors,and hyperparameter optimization was performed using the BO ***,the model performance was evaluated using two evaluation metrics,coefficient of determination(R2)and root mean square error(RMSE),and the prediction performance of other models was compared with that of the BO-XGBoost *** results show that the RMSE of the proposed BO-XGBoost for predicting LCCO_(2) in residential buildings is at least 40%lower compared to other *** method adopted in this study can help designers accurately predict building LCCO_(2) at the early design stage and provide methodological support for similar studies in the future.

关键词： building carbon emissions life cycle XGBoost Bayesian optimization predictive model

Interplay of transport processes and interfacial chemistry affecting chromium reduction and reoxidation with iron and manganese

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Frontiers of Environmental Science & Engineering 2020年第5期14卷 55-63页

作者： Chao pan Daniel Giammar Department of Energy Environmentaland Chemical EngineeringWashington University in St.LouisSt.LouisMO 63130USA Present affiliation:Glenn *** Institute Physical&Life SciencesLawrence Livermore National LaboratoryLivermoreCA 94550USA

Hexavalent chromium(Cr(Ⅵ))is a water-soluble pollutant in soil and groundwater,the mobility,bioavailability,and toxicity of which can be controlled by transforming to less mobile and more environmentally benign Cr(Ⅲ)by ways of *** review focused on recent advances in identifying the reaction pathways,kinetics,and products of iron-based techniques for Cr(Ⅵ)*** also examines new information regarding remobilization of Cr(Ⅲ)in the existence of complexing ligands and manganese(Mn)of different oxidation states.A range of iron-based techniques can remove Cr(Ⅵ)from water by adsorption or reduction-coprecipitation ***,the success of a chromium treatment or remediation strategy requires the stability of the Cr(Ⅲ)-containing solids with respect to solubilization or reoxidation in the settings they are *** is ubiquitous in aquatic and terrestrial environments,and the redox cycling of manganese may greatly influence the fate,transport,and distribution of *** of redox reactions of chromium,iron,and manganese involves reaction pathways not only in the aqueous phase but also at solid-aqueous *** provide a quantitative understanding of these processes,it is essential to develop mechanistically based kinetic and transport *** research should be made on iron-based treatment of Cr(Ⅵ)-contaminated water and soils and the stability of the subsequently produced Cr(Ⅲ)-containing solids at environmentally relevant conditions,which will support improved predictions of chromium's environmental fate and transport and aid in decision-making for remediation and treatment of Cr contamination.

关键词： Chromium(Ⅵ)contamination Redox reaction Iron oxide Manganese oxide Modeling

SOME RESULTS ON ESTIMATION OF THE TAIL INDEX OF A DISTRIBUTION

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Chinese Annals of Mathematics,Series B 1998年第2期19卷 239-248页

作者： pan JIAZHU Beijing Univ Dept Math Beijing 100871 Peoples R China

The author obtains the rate of strong convergence,mean squared error and optimal choice of the“smoothing parameter”(the sample fraction)of a tail index estimator which was proposed by the author from Pickands’estimator,and called modified Pickands’*** similar results about Hill’s estimator are also obtained,which generalize the corresponding results ***,some comparisons between Hill’s estimator and the modified Pickands’estimator are given.

关键词： Tail index Parameter estimation,Strong convergence Mean squared error Comparisons of estimators

A Wideband Self-Decoupled Microstrip Patch Antenna Array Using Characteristic Modes of Ground Plane

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Chinese Journal of Electronics 2022年第6期31卷 1161-1172页

作者： LAI Qixuan pan Yongmei School of Electronic and Information Engineering South China University of Technology

The reduction of mutual coupling between antenna elements has been a research hotspot in the design of multi-input multi-output(MIMO) *** this paper, a review of the existing theory of characteristic mode(TCM) based decoupling methods is introduced, and they are summarized and divided into two categories according to mechanisms. The first category consists of the use of the modal properties of the radiator whereas the second one is based on the ground plane to enhance isolation. Moreover, a wideband self-decoupling method is implemented for the MIMO microstrip patch antenna(MPA) array using the characteristic modes(CMs) of the ground plane. It is found that, by adjusting the dimension of the ground plane, their CMs along with two or three null-field regions, can be excited by the active MPA. When the feeding position of the adjacent passive MPA is arranged in the null-field region, the energy cannot be coupled with the receiving port, thereby achieving a good isolation level. For verification, a prototype of the proposed MIMO MPA array has been fabricated and tested. The results show that a wide usable bandwidth of 24.2% has been achieved.

关键词： antenna radiation patterns broadband antennas null-field region self-decoupling method microstrip antenna arrays characteristic mode wideband self-decoupled microstrip patch antenna array multiinput multioutput systems antenna elements ground plane mutual coupling MIMO MPA array antenna feeds MIMO microstrip patch antenna array MIMO communication

Pyrometallurgical recycling of spent lithium-ion batteries from conventional roasting to synergistic pyrolysis with organic wastes

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Journal of Energy Chemistry 2023年第10期85卷 547-561,I0014页

作者： Chao pan Yafei Shen China Energy Science and Technology Research Institute Co.Ltd. Nanjing 210023JiangsuChina Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control(AEMPC) Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science and TechnologyNanjing 210044JiangsuChina

The synergistic pyrolysis has been increasingly used for recycling spent lithium-ion batteries(LIBs)and organic wastes(hydrogen and carbon sources),which are in-situ transformed into various reducing agents such as H_(2),CO,and char via carbothermal and/or gas thermal *** with the conventional roasting methods,this“killing two birds with one stone”strategy can not only reduce the cost and energy consumption,but also realize the valorization of organic *** paper concluded the research progress in synergistic pyrolysis recycling of spent LIBs and organic *** the one hand,valued metals such as Li,Co,Ni,and Mn can be recovered through the pyrolysis of the cathode materials with inherent organic materials(e.g.,separator,electrolyte)or graphite *** the pyrolysis process,the organic materials are decomposed into char and gases(e.g.,CO,H_(2),and CH_(4))as reducing agents,while the cathode material is decomposed and then converted into Li_(2)CO_(3) and low-valent transition metals or their oxides via in-situ thermal *** formed Li_(2)CO_(3) can be easily recovered by the water leaching process,while the formed transition metals or their oxides(e.g.,Co,CoO,Ni,MnO,etc.)can be recovered by the reductant-free acid leaching or magnetic separation *** the other hand,organic wastes(e.g.,biomass,plastics,etc.)as abundant hydrogen and carbon sources can be converted into gas(e.g.,H_(2),CO,etc.)and char via *** cathode materials are decomposed and subsequently reduced by the pyrolysis gas and *** addition,the pyrolysis oil and gas can be upgraded by catalytic reforming with the active metals derived from cathode ***,great challenges are proposed to promote this promising technology in the industrial applications.

关键词： Synergistic pyrolysis Spent LIBs Biomass Recycling Reduction roasting