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Determining hydrothermal deactivation mechanisms on Cu/SAPO-34 NH_(3)-SCR catalysts at low-and high-reaction regions:establishing roles of different reaction sites

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Rare Metals 2022年第6期41卷 1899-1910页

作者： Qing-Jin Lin Ming-Ming Pei Pan Yao Shi Xu Shu-Hao Xu shuang Liu Hai-Di Xu Yi Dan Yao-qiang chen State Key Laboratory of Polymer Materials Engineering Polymer Research InstituteSichuan UniversityChengdu 610064China Key Laboratory of Green Chemistry and Technology College of ChemistrySichuan UniversityMinistry of EducationChengdu 610064China .Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu 610064China Weichai Power Co. LtdWeifang 261061China Sichuan Provincial Automobile Exhaust Purification Engineering Technology Research Center Chengdu 610064China Sichuan Provincial Environmental Protection Environmental Catalytic Materials Engineering Technology Center Chengdu 610064China

Hydrothermal deactivation is a constant chal-lenge in commercial catalytic process aimed at NOx emission control,which may be observed in the low(150-400℃)or high(400-550℃)-reaction *** the best of our knowledge,there is a lack of systematic research regarding the correlation between the reaction sites and the mechanism of hydrothermal degradation at various reaction *** a targeted investigation of this,Cu/zeolite catalysts have been prepared using different amounts of polyvinyl alcohol for adjusting their redox and acid *** catalysts exhibit hydrothermal deactivation in different reaction *** change is observed in the reaction mechanism even with hydrother-mal deactivation,but various reaction sites determine the performance deterioration in the low-and high-reaction *** redox properties and weak acid sites affect the hydrothermal deactivation in the low-reaction region,whereas the moderate/strong acid sites related to the structure mainly influence the hydrothermal deactivation in the high-reaction *** work provides several the-oretical insights for optimizing the hydrothermal stabilities of Cu/zeolite catalysts.

关键词： Deterioration mechanism Bifunctional sites Temperature regions Selective catalytic reduction Cu/zeolite

Theoretical methods for excited state dynamics of molecules and molecular aggregates

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Science China Chemistry 2013年第9期56卷 1271-1276页

作者： SHI qiang chen Hui Beijing National Laboratory for Molecular Science (BNLMS) Institute of ChemistryChinese Academy of Sciences

This contribution provides a summary of proposed theoretical and computational studies on excited state dynamics in molecular aggregates, as an important part of the National Natural Science Foundation (NNSF) Major Project entitled "Theoretical study of the low-lying electronic excited state for molecular aggregates". This study will focus on developments of novel methods to simulate excited state dynamics of molecular aggregates, with the aim of understanding several important chemical physics processes, and providing a solid foundation for predicting the opto-electronic properties of organic functional materials and devices. The contents of this study include: (1) The quantum chemical methods for electronic excited state and electronic couplings targeted for dynamics in molecular aggregates; (2) Methods to construct effective Hamiltonian models, and to solve their dynamics using system-bath approaches; (3) Non-adiabatic mixed quantum-classic methods targeted for molecular aggregates; (4) Theoretical studies of charge and energy transfer, and related spectroscopic phenomena in molecular aggregates.

关键词： excited state dynamics molecular aggregates effective Hamiltonian models mixed quantum-classical dynamics

RESERVOIR SEDIMENTATION AND TRANSFORMATION OF MORPHO-LOGY IN THE LOWER YELLOW RIVER DURING 10 YEAR'S INITIAL OPERATION OF THE XIAOLANGDI RESERVOIR

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Journal of Hydrodynamics 2012年第6期24卷 914-924页

作者： chen Jian-guo ZHOU Wen-hao chen qiang International Research and Training Center on Erosion and Sedimentation(IRTCRS) China Institute of Water Resources and Hydropower Research(IWHR)

The Xiaolangdi Hydro-Project is one of the large projects on the main stem of the Middle Yellow River. It has been operated for more than 10 years, since its impoundment in October, 1999. The reservoir has trapped 2.833 × 10^9 m3 of sediment, and caused the total erosion of 1.891 × 10^9t in the Lower Yellow River from October, 1999 through October, 2010. Not only the serious atrophied situation of the Lower Yellow River （LYR） has been resuscitating, but also many new phenomena of sediment transport and behaviors of channel re-establishing are coming into being. They are illustrated and discussed in detail in this paper.

关键词： reservoir sedimentation density current water-sediment regulation artificial flood channel siltation and erosion,erosion efficiency river configuration

Extracting optimal actionable plans from additive tree models

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Frontiers of Computer Science 2017年第1期11卷 160-173页

作者： qiang LU Zhicheng CUI Yixin chen Xiaoping chen College of Information Engineering Yangzhou University Yangzhou 225127 China Department of Computer Science and Engineering Washington University in St. Louis St. Louis MO 63130 USA School of Computer Science and Technology University of Science and Technology of China Hefei 230026 China

Although amazing progress has been made in ma- chine learning to achieve high generalization accuracy and ef- ficiency, there is still very limited work on deriving meaning- ful decision-making actions from the resulting models. How- ever, in many applications such as advertisement, recommen- dation systems, social networks, customer relationship man- agement, and clinical prediction, the users need not only ac- curate prediction, but also suggestions on actions to achieve a desirable goal （e.g., high ads hit rates） or avert an unde- sirable predicted result （e.g., clinical deterioration）. Existing works for extracting such actionability are few and limited to simple models such as a decision tree. The dilemma is that those models with high accuracy are often more complex and harder to extract actionability from. In this paper, we propose an effective method to extract ac- tionable knowledge from additive tree models （ATMs）, one of the most widely used and best off-the-shelf classifiers. We rigorously formulate the optimal actionable planning （OAP） problem for a given ATM, which is to extract an action- able plan for a given input so that it can achieve a desirable output while maximizing the net profit. Based on a state space graph formulation, we first propose an optimal heuris- tic search method which intends to find an optimal solution. Then, we also present a sub-optimal heuristic search with an admissible and consistent heuristic function which can re- markably improve the efficiency of the algorithm. Our exper- imental results demonstrate the effectiveness and efficiency of the proposed algorithms on several real datasets in the application domain of personal credit and banking.

关键词： actionable knowledge extraction machine learning additive tree models state space search

An undrained expansion solution of cylindrical cavity in SANICLAY for K_(0)-consolidated clays

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第3期14卷 922-935页

作者： Haohua chen Pin-qiang Mo China University of Mining and Technology Xuzhou 221116China The University of Arizona TucsonAZ 85716USA

This paper proposes a rigorous undrained solution for cylindrical cavity expansion problems in K_(0)-consolidated clays,adopting a simple non-associated and anisotropic model,*** cavity expansion theory is well extended to consider non-associativity,K_(0)-consolidation and stress-induced anisotropy with combined rotational and distortional hardening of yield surface and plastic potential in the multiaxial stress *** developed solution can be recovered for validation against the modified Cam-clay(MCC)solution by simply setting model constants,avoiding non-associativity and *** source code is provided to facilitate the use for *** investigating the effects of overconsolidation ratio on the cavity pressure curves,stress distributions,evolutions of anisotropic parameters and stress paths,the variations with three-dimensional(3D)evolutions of yield surface and plastic potential during undrained cavity expansion are shown for various K_(0)-consolidated clays.A parametric study on the model constants is presented to depict the influences on the stress distributions and paths,critical state surfaces and Lode’s angles at *** proposed solution also provides a general framework for formulating equations for undrained expansion of cylindrical cavities under an initial cross anisotropic condition using sophisticated anisotropic soil *** serves as a precise benchmark for extensions of analytical solutions,numerical simulations of cavity expansion,and backcalculations of geotechnical problems.

关键词： Undrained cavity expansion SANICLAY K_(0)-consolidation Anisotropy

Measures of imaginarity and quantum state order

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Science China(Physics,Mechanics & Astronomy) 2023年第8期66卷 26-35页

作者： qiang chen Ting Gao Fengli Yan School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050024China College of Physics Hebei Key Laboratory of Photophysics Research and ApplicationHebei Normal UniversityShijiazhuang 050024China

Complex numbers are widely used in classical and quantum ***,they play an important role in describing quantum systems and their dynamical ***,we propose several measures of the imaginarity of quantum states based on l1 norm and convex functions in the framework of resource ***,we investigate the quantum state order after a quantum system passes through a real *** proof shows that these proposed measures possess all the desirable properties for a measure of *** connection between the measure of imaginarity based on the l1 norm and the measure of imaginarity based on relative entropy is ***,we demonstrate that the l1 norm-based and the relative entropy-based measures of imaginarity are of the same order for qubit quantum *** we discuss the influences of the bit flip channel,phase damping channel,and amplitude flip channel on single qubit state order.

关键词： measure imaginarity quantum state order

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FINITE-TIME TRACKING CONTROL FOR MOTOR SERVO SYSTEMS WITH UNKNOWN DEAD-ZONES

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Journal of Systems Science & Complexity 2013年第6期26卷 940-956页

作者： chen qiang YU Li NAN Yurong College of Information Engineering Zhejiang University of Technology

A finite-time tracking control scheme is proposed in this paper based on the terminal sliding mode principle for motor servo systems with unknown nonlinear dead-zone *** using the differential mean value theorem,the dead-zone is represented as a time-varying system and thus the inverse compensation approach is ***,an indirect terminal sliding mode control(ITSMC)is developed to guarantee the finite-time convergence of the tracking error and to overcome the singularity problem in the traditional terminal sliding mode *** the proposed controller design,the unknown nonlinearity of the system is approximated by a simple sigmoid neural network,and the approximation error is diminished by employing a robust *** experiments on a turntable servo system are conducted to show the superior performance of the proposed method.

关键词： Dead zone finite-time control neural network servo system.

A constraint-weaving approach to points-to analysis for AspectJ

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Frontiers of Computer Science 2014年第1期8卷 52-68页

作者： qiang SUN Yuting chen Jianjun ZHAO Department of Computer Science and Engineering and School of Software Shanghai Jiao Tong University Shanghai 200240 China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China

Points-to analysis is a static code analysis tech- nique that establishes the relationships between variables of references and allocated objects. A number of points-to analysis algorithms have been proposed for procedural and object-oriented languages like C and Java, while few of them can be used for AspectJ as we know so far. One main rea- son is that Aspect/is an aspect-oriented language which im- plements the separation of crosscutting concerns by advices, pointcuts, and inter-type declarations, while a points-to anal- ysis of AspectJ programs may be imprecise because any as- pect woven into the base code may change the points-to rela- tions in the program and thus a conservative analysis has to be taken in order to handle the aspects. In this paper, we pro- pose a context-sensitive points-to analysis technique called AJPoints for AspectJ. Similar to the weaving mechanism for AspectJ, AJPoints obtains the constraints and templates on the points-to relations for the base code and the aspects, re- spectively, but weaves and solves them in an iterative manner in order to cross the boundary between the base code and the aspects. We have implemented AJPoints on abc AspectJ compiler and evaluated it by using twelve AspectJ benchmark programs. The experimental can achieve a high precision pectJ programs. results show that our technique about points-to relations in As-

关键词： points-to analysis context-sensitive analysis,AspectJ

Multidimensional Credibility Estimators with Random Common Effects and Time Effects

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Journal of Systems Science & Complexity 2017年第5期30卷 1107-1120页

作者： ZHANG qiang CUI Qianqian chen Ping School of Science Nanjing University of Science and TechnologyNanjing 210094China Department of Applied Mathematics Nanjing University of Science and TechnologyNanjing 210094China

In this paper, multidimensional credibility model with a type of dependence structures over risks and over time is considered. By means of the projection method, the inhomogeneous and homogeneous Buhlmann credibility estimators are obtained, which are extended to slightly more general versions. The inhomogeneous estimator can be expressed as the weighted sum of individual mean, overall sample mean and collective mean. In addition, the estimations of structural parameters are also investigated.

关键词： Common effects credibility estimator multidimensional credibility time effects.