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Indispensable gutter layers in thin-film composite membranes for carbon capture

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Green Energy & Environment 2024年第8期9卷 1220-1238页

作者： Gengyi zhang Haiqing Lin Department of Chemical and Biological Engineering University at Buffalo The State University at New York

Industrial thin-film composite(TFC) membranes achieve superior gas separation properties from high-performance selective layer materials,while the success of membrane technology relies on high-performance gutter layers to achieve production scalability and low-cost manufacturing. However, the current literature predominantly focuses on the design of polymer architectures to obtain high permeability and selectivity, while the art of fabricating gutter layers is usually safeguarded by industrial manufacturers and appears lackluster to academic researchers. This is the first report aiming to provide a comprehensive and critical review of state-of-the-art gutter layer materials and their design and modification to enable TFC membranes with superior separation performance. We first elucidate the importance of the gutter layer on membrane performance through modeling and experimental results. Then various gutter layer materials used to obtain high-performance composite membranes are critically reviewed, and the strategies to improve their compatibility with the selective layer are highlighted, such as oxygen plasma treatment, polydopamine deposition, and surface grafting. Finally, we present the opportunities of the gutter layer design for practical applications.

关键词： Thin-film composite membranes Gutter layer Gas separation Carbon capture

User Purchase Intention Prediction Based on Improved Deep Forest

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 661-677页

作者： Yifan zhang Qiancheng Yu Lisi zhang School of Computer Science and Engineering North Minzu UniversityYinchuan750030China Laboratory of Graphics and Images of the State Ethnic Affairs Commission North Minzu UniversityYinchuan750030China

Widely used deep neural networks currently face limitations in achieving optimal performance for purchase intention prediction due to constraints on data volume and hyperparameter *** address this issue,based on the deep forest algorithm and further integrating evolutionary ensemble learning methods,this paper proposes a novel Deep Adaptive Evolutionary Ensemble(DAEE)*** model introduces model diversity into the cascade layer,allowing it to adaptively adjust its structure to accommodate complex and evolving purchasing behavior ***,this paper optimizes the methods of obtaining feature vectors,enhancement vectors,and prediction results within the deep forest algorithm to enhance the model’s predictive *** demonstrate that the improved deep forest model not only possesses higher robustness but also shows an increase of 5.02%in AUC value compared to the baseline ***,its training runtime speed is 6 times faster than that of deep models,and compared to other improved models,its accuracy has been enhanced by 0.9%.

关键词： Purchase prediction deep forest differential evolution algorithm evolutionary ensemble learning model selection

A SINGULAR DIRICHLET PROBLEM FOR THE MONGE-AMPÈRE TYPE EQUATION

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Acta Mathematica Scientia 2024年第5期44卷 1965-1983页

作者： Zhijun zhang Bo zhang School of Mathematics and Information Science Yantai UniversityYantai264005China

We consider the singular Dirichlet problem for the Monge-Ampère type equation{\rm det}\D^2 u=b(x)g(-u)(1+|\nabla u|^2)^{q/2},\u<0,\x\in\Omega,\u|_{\partial\Omega}=0,whereΩis a strictly convex and bounded smooth domain inℝn,q∈[0,n+1),g∈C∞(0,∞)is positive and strictly decreasing in(0,∞)with\lim\limits_{s\rightarrow 0^+}g(s)=\infty,and b∈C∞(Ω)is positive inΩ.We obtain the existence,nonexistence and global asymptotic behavior of the convex solution to such a problem for more general b and *** approach is based on the Karamata regular variation theory and the construction of suitable sub-and super-solutions.

关键词： Monge-Ampère equation a singular boundary value problem the unique convex solution global asymptotic behavior

Design and identification of a double-acting piezoelectric-hydraulic hybrid actuator

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Chinese Journal of Aeronautics 2024年第3期37卷 456-467页

作者： Junjian zhang Zhihua FENG Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes University of Science and Technology of ChinaHefei 230026China

Traditional single-acting piezoelectric-hydraulic hybrid actuators usually have the problem of inertial force caused by flow pulsation of the liquid,which degrades their output *** suppress or solve the associated inertial force and enhance its output capabilities,this paper proposes a new type of double-acting piezoelectric-hydraulic hybrid actuator with four check valves acting as mechanical *** new hybrid actuator was fabricated and its output performance was *** the voltage is 700 Vp-pand the bias pressure is 2 MPa,the pulsation ratesδof the new actuator at 400 Hz,500 Hz and 600 Hz are 2.29,2.08 and 1.78,respectively,whileδof the single-acting hybrid actuator under the same conditions are 10.98,11.05 and ***,the liquid pulsation rate of the new hybrid actuator is significantly reduced,which is beneficial for improving the flow uniformity and weakening the influence of inertial force on the hybrid *** strategy ultimately leads to a maximum no-load velocity of 168.1 mm/s at 600 Hz and a maximum blocking force of 141 N at 450 Hz for the new hybrid *** addition,this strategy has the potential to be used in other electrohydrostatic actuators to improve their performance.

关键词： Double-acting Flow pulsation Inertial force Piezoelectric actuators Piezoelectric devices Piezoelectric hydraulic actuation Piezoelectric pump

Distributed velocity-free formation tracking control for clustered UAVs under virtual leader-follower framework

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Science China(Technological Sciences) 2024年第5期67卷 1538-1552页

作者： zhang ZhaoYu DUAN HaiBin School of Automation Science and Electrical Engineering Beihang UniversityBeijing100083China

The collective formation control problem of a cluster of rotorcraft unmanned aerial vehicles(UAVs)is investigated in this *** consensus tracking towards formation centroid with following UAVs forming a predefined configuration around the leader is considered as the *** prior studies,the information of the central reference trajectory,which is deemed as a virtual leader in the leader-follower topology,is not directly accessible for partial nodes through the communication ***,a novel distributed formation tracking control scheme is ***,a decentralized saturation observer is employed to estimate the reference acceleration signal of the virtual *** the absence of linear velocity measurement,two sliding manifolds are proposed by introducing the relative discrepancy terms of position and *** a smooth saturation operator in the form of a sigmoid function is applied to generate the command force ***,under the dilemma of constrained capabilities of the airborne sensors equipped on the rotorcrafts,the angular velocity is difficult to *** cascaded auxiliary attitude error systems are established on each rotorcraft system to synthesize the rotating torque with no need to require the angular velocity *** to the strong coupling and nonlinearity of the rotorcraft UAV system,the command angular velocity and the derivatives of command input are hard to *** a continuous nonlinear differentiator is proposed to work with the difficulties in deriving the explicit expression of system ***,a detailed stability analysis is conducted progressively on the angular control loop,reference trajectory observer loop,and the position control loop.A simulation scheme for a cluster of four rotorcraft UAVs tracking sinusoidal trajectory are presented and the formation control results are proven advantageous in comparison with the control protocol in previous literature.

关键词： distributed formation control unmanned rotorcraft clusters velocity-free tracking nonlinear differentiator

Insights into the mechanism of multiple Cu-doped Co Fe_(2)O_(4)nanocatalyst activated peroxymonosulfate for efficient degradation of Rhodamine B

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Journal of Environmental Sciences 2024年第3期137卷 382-394页

作者： Yuanmin Mo Xiaoping zhang School of Environment&Energy South China University of TechnologyGuangzhou Higher Education Mega CentreGuangzhou 510006China The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education Guangzhou 510006China Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling Guangzhou 510006China Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal Guangzhou 510006China

The multiple metal catalyst as a promising nanomaterial has shown excellent activity in the peroxymonosulfate(PMS)activation for pollutant ***,the role of special sites and in-depth understanding of the PMS activation mechanism are not fully *** this study,a Cu-doped CoFe_(2)O_(4)nanocatalyst(0.5CCF)was synthesized by a sol-gel and calcination method,and used for PMS activation to remove Rhodamine B(RhB).The results showed that the Cu doping obviously enhanced the catalytic performance of CoFe_(2)O_(4),with 99.70%of RhB removed by 0.5CCF while 74.91%in the CoFe_(2)O_(4)within 15 *** on the X-ray photoelectron spectroscopy and electrochemical analysis,this could be ascribed to the more low valence of Co and Fe species generated on the 0.5CCF and faster electron transfers occurred in the 0.5CCF due to the Cu *** addition,Cu doping could provide more reaction sites for the 0.5CCF to activate PMS for RhB *** metal species and the surface hydroxyl were the reaction sites of PMS activation,and the surface hydroxyl played an important role in surface-bound reactive species *** the PMS activation,the Cu not only activated PMS to produce reactive oxygen species(ROS),but also regenerated Co^(2+)and Fe^(2+)to accelerate the PMS *** non-radical of ^(1)O_(2)was the main ROS with a 99.35%of contribution rate,and the SO_(5)^(·–)self-reaction was its major *** study provides a new insight to enhance the PMS activation performance of multiple metal catalysts by Cu doping in wastewater treatment.

关键词： Cu-doped CoFe_(2)O_(4)nanocatalyst PMS activation Mechanism Rhodamine B removal

Seasonal thermal energy storage using natural structures:GIS-based potential assessment for northern China

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Building Simulation 2024年第4期17卷 561-574页

作者： Yichi zhang Jianjun Xia Midea HVAC Heating&Ventilation Equipment Co. LtdFoshan528311China Building Energy Research Center Tsinghua UniversityBeijing100084China

Seasonal thermal energy storage(STES)allows storing heat for long-term and thus promotes the shifting of waste heat resources from summer to winter to decarbonize the district heating(DH)*** being a promising solution for sustainable energy system,large-scale STES for urban regions is lacking due to the relatively high initial investment and extensive land *** close the gap,this study assesses the potentials of using two naturally available structures for STES,namely valley and ground pit *** on geographical information system(GIS)methods,the available locations are searched from digital elevation model and selected considering several criteria from land uses and construction *** costs of dams to impound the reservoir and the yielded storage capacities are then quantified to guide the choice of suitable *** assessment is conducted for the northern China where DH systems and significant seasonal differences of energy demand *** total,2,273 valley sites and 75 ground pit sites are finally identified with the energy storage capacity of 15.2 billion GJ,which is much larger than the existing DH demand in northern *** results also prove that 682 valley sites can be achieved with a dam cost lower than 20 CNY/m^(3).By conducting sensitivity analysis on the design dam wall height and elevations,the choices of available natural structures are expanded but practical issues about water pressures and constructions are also ***,the identified sites are geographically mapped with nearest urban regions to reveal their roles in the DH *** general,560 urban regions are found with potential STES units and most of them have STES storage capacities larger than their own DH *** novel planning methodology of this study and publicly available datasets create possibilities for the implementations of large-scale STES in urban DH systems.

关键词： seasonal thermal energy storage geographical information system district heating water reservoir

Geometric Error Identification of Gantry-Type CNC Machine Tool Based on Multi-Station Synchronization Laser Tracers

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 150-162页

作者： Jun Zha Huijie zhang School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China Xi’an Jiaotong University Suzhou Academy Suzhou 215123China

Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial *** propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine *** method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement *** consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic *** four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization *** experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser *** a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed *** research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.

关键词： Multi-point positioning Multi-station synchronization CNC machine tool Geometric error Error separation

Classification of knowledge graph completeness measurement techniques

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Journal of Systems Engineering and Electronics 2024年第1期35卷 154-162页

作者： zhang Ying XIAO Gang Institute of Systems Engineering Academy of Military SciencesBeijing 100107China

At present,although knowledge graphs have been widely used in various fields such as recommendation systems,question and answer systems,and intelligent search,there are always quality problems such as knowledge omissions and *** assessment and control,as an important means to ensure the quality of knowledge,can make the applications based on knowledge graphs more complete and more accurate by reasonably assessing the knowledge graphs and fixing and improving the quality problems at the same ***,as an indispensable part of the knowledge graph construction process,the results of quality assessment and control determine the usefulness of the knowledge *** them,the assessment and enhancement of completeness,as an important part of the assessment and control phase,determine whether the knowledge graph can fully reflect objective phenomena and reveal potential connections among *** this paper,we review specific techniques of completeness assessment and classify completeness assessment techniques in terms of closed world assumptions,open world assumptions,and partial completeness *** purpose of this paper is to further promote the development of knowledge graph quality control and to lay the foundation for subsequent research on the completeness assessment of knowledge graphs by reviewing and classifying completeness assessment techniques.

关键词： quality assessment completeness assessment closed world assumptions open world assumption partial completeness assumption