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Mass transfer enhancement and hydrodynamic performance with wire mesh coupling solid particles in bubble column reactor

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Chinese Journal of Chemical Engineering 2024年第3期67卷 195-205页

作者： Chuanjun Di Jipeng dong Fei Gao Guanghui Chen Pan zhang Jianlong Li Key Laboratory of Multiphase Flow Reaction and Separation Engineering of Shandong Province College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China College of Electromechanical Engineering Qingdao University of Science and TechnologyQingdao 266043China

It is of vital significance to investigate mass transfer enhancements for chemical engineering *** work focuses on investigating the coupling influence of embedding wire mesh and adding solid particles on bubble motion and gas-liquid mass transfer process in a bubble *** image velocimetry(PIV)technology was employed to analyze the flow field and bubble motion behavior,and dynamic oxygen absorption technology was used to measure the gas-liquid volumetric mass transfer coefficient(kLa).The effect of embedding wire mesh,adding solid particles,and wire mesh coupling solid particles on the flow characteristic and kLa were analyzed and *** results show that the gas-liquid interface area increases by 33%-72%when using the wire mesh coupling solid particles strategy compared to the gas-liquid two-phase flow,which is superior to the other two strengthening *** with the system without reinforcement,kLa in the bubble column increased by 0.5-1.8 times with wire mesh coupling solid particles method,which is higher than the sum of kLa increases with inserting wire mesh and adding particles,and the coupling reinforcement mechanism for affecting gas-liquid mass transfer process was discussed to provide a new idea for enhancing gas-liquid mass transfer.

关键词： Fluid mechanics Bubble Mass transfer Wire mesh coupling solid particles Particle image velocimetry Hydrodynamics

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Efficient and selective upcycling of waste polylactic acid into acetate using nickel selenide

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Journal of Energy Chemistry 2024年第10期97卷 575-584页

作者： Bing Lan Yinfang Chen Nantian Xiao Na Liu chao Juan Chuan Xia Fan zhang National Engineering Laboratory of Eco-Friendly Polymeric Materials College of Chemistry Sichuan University School of Materials and Energy University of Electronic Science and Technology of China

The conversion of waste polylactic acid（PLA） plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable ***,developing efficient and highly selective catalysts for lactic acid oxidation reaction（LAOR） and understanding the reaction process are ***,we report the electrooxidation of waste PLA to acetate at a high current density of 100 mA cm-2 with high Faraday efficiency（～95%） and excellent stability（>100 h） over a nickel selenide nanosheet *** addition,a total Faraday efficiency of up to 190% was achieved for carboxylic acids,including acetic acid and formic acid,by coupling with the cathodic CO2reduction *** situ experimental results and theoretical simulations revealed that the catalytic activity center of LAOR was dynamically formed NiOOH species,and the surface-adsorbed SeOxspecies accelerated the formation of Ni3+species,thus promoting catalytic *** mechanism of lactic acid electrooxidation was further *** acid was dehydrogenated to produce pyruvate first and then formed CH3CO due to preferential C-C bond cleavage,resulting in the presence of *** work demonstrated a sustainable method for recycling waste PLA and CO2into high-value-added products.

关键词： Acetic acid Lactic acid electro-oxidation Poly (lactic acid) Waste plastic upcycling

Thermofluidic investigations of oil natural transformer:Closed-loop modelling and experimental validation

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High Voltage 2024年第1期9卷 230-240页

作者： Yuan Li Yiran Gao Chen Wang chao Zhu Ying Li Yuankai Wang Guanjun zhang State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina Electric Power Research Institute of State Grid Shaanxi Electric Power Co. Ltd.Xi'anChina TBEA Hengyang Transformer Co. Ltd.HengyangChina

Excessively high temperatures inside a power transformer can accelerate the ageing rate and even cause unplanned *** estimating the hot-spot temperature(HST)of a power transformer is important for regulating the load and ensuring long-term *** this study,a closed-loop model of a 110-kV product transformer with an oil natural/air forced(ONAF)cooling mode is built to predict HST,in which the compression ratio of windings,equivalent heat source and radiator geometry are *** to the flow field of the winding,the‘dead oil zone’and reverse oil flow are observed in the horizontal oil *** accuracy of the proposed model is experimentally validated by temperature-rise *** results show that the absolute errors between the measured results and simulation are below 5°C,and the average error is~2°***,the arrangements of windings and radiators are studied to enhance the oil *** adding 5 washers to the high-voltage winding,the average temperature can be decreased by 6°C compared with the case without a *** the radiator can also mitigate the characteristic temperatures,and the optimal height difference between the radiator and winding centre is suggested to be 0.66 m.

关键词： winding arrangement adding

Porous nanocomposites with enhanced intrinsic piezoresistive sensitivity for bioinspired multimodal tactile sensors

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Microsystems & Nanoengineering 2024年第1期10卷 243-256页

作者： Jianpeng zhang Song Wei Caichao Liu chao Shang Zhaoqiang He Yu Duan Zhengchun Peng State Key Laboratory of Radio Frequency Heterogeneous Integration(Shenzhen University) School of Physics and Optoelectronic EngineeringShenzhen University518060 ShenzhenGuangdong ProvinceP.R.China Linksense Technology Ltd. 518060 ShenzhenGuangdong ProvinceP.R.China

In this work,we propose porous fluororubber/thermoplastic urethane nanocomposites(PFTNs)and explore their intrinsic piezoresistive sensitivity to *** experiments reveal that the intrinsic sensitivity of the PFTN-based sensor to pressure up to 10 kPa increases up to 900%compared to the porous thermoplastic urethane nanocomposite(PTN)counterpart and up to 275%compared to the porous fluororubber nanocomposite(PFN)*** pressures exceeding 10 kPa,the resistance-pressure relationship of PFTN follows a logarithmic function,and the sensitivity is 221%and 125%higher than that of PTN and PFN,*** the excellent intrinsic sensitivity of the thick PFTN film,a single sensing unit with integrated electrode design can imitate human skin for touch detection,pressure perception and traction *** sensing range of our multimodal tactile sensor reaches~150 Pa,and it exhibits a linear fit over 97%for both normal pressure and shear *** also demonstrate that an electronic skin,made of an array of sensing units,is capable of accurately recognizing complex tactile interactions including pinch,spread,and tweak motions.

关键词： sensation intrinsic modal

Robust, breathable, and chemical-resistant polytetrafluoroethylene (PTFE) films achieved by novel in-situ fibrillation strategy for highperformance triboelectric nanogenerators

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Nano Research 2024年第3期17卷 1942-1951页

作者： Jialong Chai Guilong Wang Jinchuan Zhao Guizhen Wang chao Wei Aimin zhang Guoqun Zhao Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China Key Laboratory of Chinese Education Ministry for Tropical Biological Resources Hainan UniversityHaikou 570228China

In the era of advanced wearable electronic devices,the triboelectric nanogenerators(TENGs)as energy harvesting and self-powered sensing units hold great *** appropriate triboelectric material is the crucial factor to optimize the performance of TENG,while polytetrafluoroethylene(PTFE)stands out as a highly versatile option among the various *** this study,we present an ultrafine nanofibrous PTFE(NF-PTFE)films prepared by novel in-situ fibrillation strategy as the triboelectric material in TENG *** innovative processing methodology facilely addresses the dilemma between high porosity and fine pore size of traditional porous PTFE films,meanwhile achieves exceptional mechanical strength,hydrophobicity,air permeability,and chemical resistance of the *** the integration of nanofibrous PTFE films into contact-separation mode TENG and droplet-based TENG,these devices realize the peak electrical output of 131 V/10.8μA and 54 V/14μA with great durability,which surpass the performance of TENGs using traditional expanded PTFE ***,a smart glove capable of recognizing hand gestures is proposed,which demonstrates the versatility,flexibility,and practicality of this material for potential use in smart *** reported NF-PTFE film provides insights for the design of high-performance TENG device for advanced wearable electrical applications.

关键词： polytetrafluoroethylene(PTFE) nanofibrous film hydrophobic triboelectric nanogenerator self-powered sensor

Deformation characteristics and analog modeling of transtensional structures in the dongying Sag,Bohai Bay Basin

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Frontiers of Earth Science 2024年第1期18卷 227-241页

作者： Dawei dong Li ZHAO Weizhong zhang Jiyan LI Ruixiang zhang Jianlei YANG Guangzeng WANG Shandong Institute of Petroleum and Chemical Technology Dongying 257061China College of Resources and Environment Shandong Agriculture UniversityTai᾽an 271018China Geophysical Research Institute of Shengli Oilfield Branch Company SINOPECDongying 257022China Research Institute of Petroleum Exploration&Development Shengli Oilfield CompanySINOPECDongying 257000China College of Marine Geosciences Ocean University of ChinaQingdao 266100China

Hydrocarbon exploration in the dongying Sag is constrained by the development of many Cenozoic transtensional structures with complex patterns and dynamic *** study uses seismic interpretation and analog modeling to investigate these transtensional *** results include dividing these transtensional structures into boundary fault,oblique rifting,and deep strike-slip fault controlled structures,according to the relationships between main and secondary *** developed in the steep slope zone,the central sag zone,and the slope zone,*** profile,the transtensional structures formed appear to be semi-flower-like,step-like,or *** plan-view,they appear to be broom-like,soft-linked,or en-echelon ***,these transtensional structures are controlled by the oblique normal slip of boundary faults,by the oblique extension of sub-sags,and by the later extension of deep strike-slip *** geometric deformation of these transtensional structures is controlled by the angles between the regional extension direction and the strike of boundary faults,deep faults,or sub-sags,where a larger angle corresponds to less developed transtensional ***,the transtensional structures in the dongying Sag were created by multi-phase and multi-directional extensions in the Cenozoic—which is also controlled by pre-existing *** strike of newborn secondary faults was determined by the regional extension direction and pre-existing structures.

关键词： transtensional structure seismic interpretation analogue modeling dynamic mechanism dongying Sag

Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji Xiao-song zhang Chen-jun Yang Xiao-qian dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research Center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise *** blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance *** the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence *** measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip *** strong fluctuations of duct-surface pressures are caused by intensive tip separation *** duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces

Hydrodynamic analysis of carbon nanotube clusters in distributor-less conical fluidized beds with step-by-step scaling

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Chinese Journal of Chemical Engineering 2024年第3期67卷 117-125页

作者： Tianle zhang Wenjuan Bai Qianpeng dong Dianming Chu Lianlian Wang Yan He Shandong Engineering Laboratory for Preparation and Application of High-performance Carbon-Materials College of Electromechanical EngineeringQingdao University of Science and TechnologyQingdao 266061China Shandong Dazhan Nano Materials Co. Ltd.Binzhou 256220China

As a high-performance material with great application potential,the application of carbon nanotubes has been limited by their production volume.A distributor-less conical fluidized bed is the main equipment used in the industrial production of carbon *** improve the production volume and product quality of carbon nanotubes,the study of fluidized-bed-diameter scaling is *** different diameters of distributor-less conical fluidized beds were established,and then the particle behavior and bubble characteristics of carbon nanotube clusters at these bed diameters were ***-series and wavelet analysis methods were used to analyze the pressure-fluctuation signals inside the fluidized *** showed that the distributor-less design caused the airflow to break through the middle of the bed,which did not change with the change in bed *** powder-bridging phenomenon of carbon nanotube clusters in a 100-mm-diameter fluidized bed was related to the special microstructure of carbon nanotube *** frequency of pressure fluctuations in the bed decreased nonlinearly with increasing bed *** study can guide the design and scale-up of distributor-less conical fluidized beds,especially for the scale-up of carbon nanotube production equipment,which can contribute to the improvement of carbon nanotubes’capacity and quality in industrial production.

关键词： Carbon nanotubes Fluidized bed Multiphase flow Scale-up Multiscale

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Crystalline carbon nitride with in-plane built-in electric field accelerates carrier separation for excellent photocatalytic hydrogen evolution

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Chinese Chemical Letters 2024年第4期35卷 160-165页

作者： Wengao Zeng Yuchen dong Xiaoyuan Ye Ziying zhang Tuo zhang Xiangjiu Guan Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

Achieving a high carrier migration efficiency by constructing built-in electric field is one of the promising approaches for promoting photocatalytic activity. Herein, we have designed a donor-acceptor(D-A) crystalline carbon nitride(APMCN) with 4-amino-2,6-dihydroxypyrimidine(AP) as electron donor, in which the pyrimidine ring was well embedded in the heptazine ring via hydrogen-bonding effect during hydrothermal process. The APMCN shows superior charge-transfer due to giant built-in electric field(5.94times higher than pristine carbon nitride), thereby exhibiting excellent photocatalytic H_(2) evolution rate(1350 μmol/h) with a high AQY(62.8%) at 400 nm. Mechanistic analysis based on detailed experimental investigation together with theoretical analysis reveals that the excellent photocatalytic activity is attributed to the promoted charge separation by the giant internal electric field originated from the D–A structure.

关键词： Crystalline carbon nitride Built-in electric field Donor-acceptor structure Photocatalysis Hydrogen production

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