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Microfluidic-oriented synthesis of enriched iridium nanodots/carbon architecture for robust electrocatalytic nitrogen fixation

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Green Energy & Environment 2024年第3期9卷 544-555页

作者： Hengyuan liu xingjiang Wu Yuhao Geng xin li Jianhong Xu The State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing100084China

Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless ***,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic ***,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon *** to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption *** a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73.μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH ***,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.3.%are also achieved in H_(2)SO_(4) *** microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.

关键词： Iridium nanodots Carbon Microfluidic technology Efficient synthesis Electrocatalytic nitrogen fixation

limits of Uneven Battery Power in Modular Multilevel Converter-based Battery Energy Storage Systems

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 686-695页

作者： Yao Pan Xiaofeng Sun Wei Zhao xin li Yao Cai Institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004China

For modular multilevel converter-based battery energy storage systems (MMC-BESS), uneven power among batteries of SMs will be deduced by battery aging, battery fault, etc., which will degrade performance and even lead to system failure. For maintaining the balance of capacitor voltage, this paper analyzes the limits of the uneven power of batteries, which are presented as the current limits in this paper. According to analysis, an analytical method is proposed that only the dc and fundamental frequency components of the arm current are used to calculate current limits. With the current limits it is able to evaluate the reasonability of power distribution among batteries. Meanwhile, increase of fundamental frequency component will enhance the current limits, and the dc component determines the size relationship between the absolute values of the upper and lower current limits. Finally, simulation model and experiment prototype are built for verifying the theoretical analysis and current limits calculation method, and satisfactory results are provided.

关键词： Arm current balance of capacitor voltage current limits MMC-BESS uneven power

A program logic for obstruction-freedom

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Frontiers of Computer Science 2024年第06期18卷 1-16页

作者： li Zhao-Hui FENG xin-Yu School of Computer Science and Technology University of Science and Technology of China Department of Computer Science and Technology Nanjing University State Key Laboratory for Novel Software Technology Nanjing University

Though obstruction-free progress property is weaker than other non-blocking properties including lock-freedom and wait-freedom, it has advantages that have led to the use of obstruction-free implementations for software transactional memory (STM) and in anonymous and fault-tolerant distributed computing. However, existing work can only verify obstruction-freedom of specific data structures (e.g., STM and list-based algorithms).In this paper, to fill this gap, we propose a program logic that can formally verify obstruction-freedom of practical implementations, as well as verify linearizability, a safety property, at the same time. We also propose informal principles to extend a logic for verifying linearizability to verifying obstruction-freedom. With this approach, the existing proof for linearizability can be reused directly to construct the proof for both linearizability and ***, we have successfully applied our logic to verifying a practical obstruction-free double-ended queue implementation in the first classic paper that has proposed the definition of obstruction-freedom.

关键词： verification program logic progress properties obstruction-freedom concurrent objects

A Review of Basic Mechanical Properties of Bamboo Scrimber Based on Small-Scale Specimens

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Journal of Renewable Materials 2024年第4期12卷 869-894页

作者： xin Xue Haitao li Rodolfo Lorenzo College of Civil Engineering Nanjing Forestry UniversityNanjing210037China National-Provincial Joint Engineering Research Center of Biomaterials for MACHINERY PACKAGE Nanjing Forestry UniversityNanjing210037China Jiangsu Engineering Research Center of Bamboo and Wood Carbon FixationMaterials and Structures Nanjing Forestry UniversityNanjing210037China Department of Civil Environmental and Geomatic EngineeringUniversity College LondonLondonWC1E 6BTUK

This review summarizes the existing knowledge about the mechanical properties of bamboo scrimber(BS)in *** to literature reviews,the strength of BS under different load modes is affected by a series of factors,such as the type of original bamboo,growth position,resin content,treatment method and ***,different production processes can be adopted according to different requirements,and bamboo scrimbers can also be classified *** addition,this review summarizes the changes in different factors considered by scholars in the research on the mechanical properties of BS,so that readers can have an overall understanding of the existing research and make more innovative and valuable research on this *** review provides and discusses the conclusive observations,the current research gaps and future research directions on the mechanical properties of BS.

关键词： Bamboo scrimber manufacturing process mechanical properties failure modes constitutive model

Adaptive security control of time-varying constraints nonlinear cyber-physical systems with false data injection attacks

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Journal of Control and Decision 2024年第1期11卷 50-59页

作者： Yue-Ming Wang Yuan-xin li Department of Science Liaoning University of TechnologyJinzhouPeople’s Republic of China

In this article,an adaptive security control scheme is presented for cyber-physical systems(CPSs)suffering from false data injection(FDI)attacks and time-varying state ***,an adaptive bound estimation mechanism is introduced in the backstepping control design to mitigate the effect of FDI ***,to solve the unknown sign time-varying statefeedback gains aroused by the FDI attacks,a type of Nussbaum function is employed in the adaptive security ***,by constructing a barrier Lyapunov function,it can be ensured that all signals of controlled system are bounded and the time-varying state constraints are not ***,the provided simulation examples demonstrate the effectiveness of the proposed controller.

关键词： Neural networks backstepping technology false data injection(FDI)attacks nonlinear cyber-physical systems controls

Tb(Ⅲ)functionalized MOF based self-calibrating sensor integrated with logic gate operation for efficient epinephrine detection in serum

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Journal of Rare Earths 2024年第5期42卷 987-994,I0006页

作者： Dongsheng Zhao Wenqian li Rongmei Wen Wencui li xin liu Xiutang Zhang liming Fan Shanxi Key Laboratory of Advanced Carbon Electrode Materials Shanxi Coal Mine Water Treatment Technology Innovation CenterSchool of Chemistry and Chemical EngineeringNorth University of ChinaTaiyuan030051China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) College of ChemistryNankai UniversityTianjin300071China

By anchoring Tb^(3.)ions on its free carboxyl groups of the nanocaged NiMOF,a dual-emission self-calibrating sensor of Tb^(3.)@NiMOF was fabricated through coordination post-synthetic modification(PSM)*** Tb^(3.)ions as the secondary fluorescent signal and sensing active sites,Tb^(3.)@NiMOF presents great potentials in visually and efficiently monitoring EPI in serum,with high sensitivity and selectivity,fast response,excellent recyclable,and the low detection limit(LOD,3.06 ng/mL).Furthermore,a tandem combinational logic gate based intelligent detection system was constructed to improve the practicability and convenience of epinephrine(EPI)detection in serum by comparing the light emitted colour with the series standard colour cards preset in the *** work provides a promising approach of developing metal-organic frameworks(MOFs)based self-calibrating sensors for intelligent detection of bioactive molecules.

关键词： Metal-organic framework Post-synthetic modification Self-calibrating sensor Logic gate operation Epinephrine detection Rare earths

The influences of perforating phase and bedding planes on the fracture deflection in laminated shale

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Petroleum Science 2024年第2期21卷 1221-1230页

作者： Ming-Zhe Gu Mao Sheng Xiao-Ying Zhuang xin-Yi li Gen-Sheng li National Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China College of Petroleum Engineering China University of PetroleumBeijing102249China College of Civil Engineering Tongji UniversityShanghai200092China

The perforating phase leads to complex and diverse hydraulic fracture propagation behaviors in laminated shale formations. In this paper, a 2D high-speed imaging scheme which can capture the interaction between perforating phase and natural shale bedding planes was proposed. The phase field method was used to simulate the same conditions as in the experiment for verification and hydraulic fracture propagation mechanism under the competition of perforating phase and bedding planes was *** results indicate that the bedding planes appear to be no influence on fracture propagation while the perforating phase is perpendicular to the bedding planes, and the fracture propagates along the perforating phase without deflection. When the perforating phase algins with the bedding planes, the fracture initiation pressure reserves the lowest value, and no deflection occurs during fracture propagation. When the perforating phase is the angle 45°, 60°and 75°of bedding planes, the bedding planes begin to play a key role on the fracture deflection. The maximum deflection degree is reached at the perforating phase of75°. Numerical simulation provides evidence that the existence of shale bedding planes is not exactly equivalent to anisotropy for fracture propagation and the difference of mechanical properties between different shale layers is the fundamental reason for fracture deflection. The findings help to understand the intrinsic characteristics of shale and provide a theoretical basis for the optimization design of field perforation parameters.

关键词： Shale Propagation Perforating Bedding Structure

Experimental validation of adsorption filter model under dynamic VOC concentrations:Prediction of long-term efficiency

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Building Simulation 2024年第7期17卷 1201-1212页

作者： Ruiyan Zhang Ziying li Xiangyuan Guan xin Wang Fei Wang lingjie Zeng Zhenhai li School of Environment and Architecture University of Shanghai for Science and TechnologyShanghai 200093China School of Mechanical Engineering Tongji UniversityShanghai 200092China

Indoor volatile organic compound(VOC)concentrations are often dynamic because the ventilation and emission rates of VOC usually *** filters used for air purification may operate with a capacity that fluctuates with unsteady VOC concentrations in *** the dynamic interactions between adsorption filters and indoor air is crucial for predicting their performance under real-world *** study presents a numerical model of partially reversible adsorption equilibrium coupled with a mass transfer model to create a predictive model for adsorption efficiency in environments with dynamic VOC concentrations.A honeycomb adsorption filter for benzene adsorption was simulated and tested,including the breakthrough and purging curve and the long-term efficiency in an experimental chamber with dynamic *** results reveal that the curve generated with the partially reversible adsorption equilibrium model closely aligns with the measured ***,the model was coupled with a chamber model and the simulation results were compared with those calculated using the filter model with a single adsorption *** VOCs were emitted intermittently in the chamber and there was sufficient ventilation,the concentration peaks in the chamber derived from the models with different assumptions on adsorption reversibility were significantly different from each ***,it was observed that the reversible adsorption capacity of the filter was crucial for long-term operation in rooms with dynamic *** the reversible adsorption capacity constituting only 6.7%of the total adsorption capacity of the tested filter,it contributes to a significant“peak shaving and valley filling”effect,even when the irreversible adsorption capacity is *** adsorption reversibility should be taken as an important parameter for selecting adsorbents for dynamic concentration conditions.

关键词： adsorption filter efficiency model indoor air partially reversible adsorption

Water modeling on fluid flow and mixing phenomena in a BOF steelmaking converter

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Journal of Iron and Steel Research International 2024年第3期31卷 595-607页

作者： xin-yu Cai Hao-jian Duan Ding-han li Anjun Xu li-feng Zhang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

A 1∶8 physical water model was constructed to investigate the fluid flow and mixing phenomena in the basic oxygen furnace(BOF)*** particle image velocimetry was employed to measure the velocity distribution of the bath and the high-speed camera was applied to capture the cavity shape in the combined blowing BOF *** mixing time for varied operating conditions was measured by the stimulus-response *** cavity depth increased with the decrease in the lance height and the increase in the top gas flow rate while the bottom blowing gas had little influence on the cavity *** minimum cavity depth was obtained under the condition of a 69.8 m^(3./h top gas flow rate,a 287.5 mm lance height and a 0.93.m^(3./h bottom blowing gas flow rate,which was 161.2 *** mixing time decreased as the lance height decreased and the top blowing gas flow rate *** mixing time was first decreased and then increased with the increase in the bottom gas flow *** the condition of 69.8 m^(3./h gas flow rate of top blowing,the 287.5 mm lance height and the 0.93.m^(3./h gas flow rate of bottom blowing,the mixing time in the converter was 48.65 *** empirical formula between the stirring power and the mixing time in the converter was calculated.

关键词： Water model Fluid flow Particle image velocimetry Mixing time BOF converter