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Effects of the nozzle structure and fluidized gas composition on the gas-particle two-phase jet characteristic in a powder fuel scramjet

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Particuology 2024年第9期92卷 166-179页

作者： Changfei Zhuo Hongming Ding Xiaobin Ren Hanyu Deng Xiong Chen School of mechanical and engineering Key Laboratory of Special Engine TechnologyMinistry of EducationNanjing University of Science and TechnologyNanjing210094China department of mechanical engineering National University of Singapore9 Engineering Drive 1Singapore117576 Shanxi North Xing'an Chemical Industry Co. Ltd.Taiyuan030008China

The interaction between nozzle design and fluidization gas composition significantly influences the dynamics within a powder fuel scramjet's combustion *** investigate this relationship,an experimental study utilized high-speed shadow imaging technology to explore the macroscopic aspects of powder fuel *** investigation examined various convergence angles,nozzle throat lengths,and fluidized gas *** findings include:During jet development,powder fuel initially concentrates near the axis,with non-convergence angle nozzles exhibiting longer concentrated distribution periods than convergence angle *** nozzle convergence angles lead to increased penetration distance,frontal velocity,and radial diffusion distance during the initial stages of jet ***,stable jet shapes show larger divergence angles as nozzle convergence angle decreases,with the largest divergence angle observed atα=60°.In the initial 0-7 ms of jet development,the powder fuel jet demonstrates greater penetration distance and frontal velocity under certain ***,penetration distance and frontal velocity increase with throat length from 7 to 20 ms,accompanied by changes in divergence ***,at a throat length(l)of 2 mm,the near-field divergence angle measures 46.50°,and the far-field divergence angle is 22.25°.Conversely,at l=8mm,the near-field divergence angle is 33.49°,and the far-field divergence angle is 23.21°.The fluidization gas composition minimally affects jet penetration distance and frontal velocity during the initial 0-3 ***,due to hydrogen's low density,hydrogen/powder fuel jets exhibit shorter distances and velocities compared to nitrogen/powder fuel *** fluidization also results in larger divergence angles,particularly in the near *** findings underscore the importance of nozzle design and fluidization gas composition in optimizing scramjet performance and efficiency.

关键词： Multiphase flows Gas-particle two-phase jet Nozzle contraction angle Powder fuel scramjet

Mg/MgO interfaces as efficient hydrogen evolution cathodes causing accelerated corrosion of additive manufactured Mg alloys:A DFT analysis

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Journal of Magnesium and Alloys 2024年第1期12卷 110-119页

作者： Man-Fai Ng Kai Xiang Kuah Teck Leong Tan Daniel John Blackwood department of Materials Science&engineering National University of Singapore9 Engineering Drive 1Singapore 117575Republic of Singapore Institute of High Performance Computing(IHPC) Agency for ScienceTechnology and Research(A∗STAR)1 Fusionopolis Way#16-16 ConnexisSingapore 138632Republic of Singapore

The corrosion rates of additive-manufactured Mg alloys are higher than their as-cast counterparts,possibly due to increased kinetics for the hydrogen evolution reaction on secondary phases,which may include oxide *** Kelvin Probe Force Microscopy demonstrated that MgO inclusions could act as cathodes for Mg corrosion,but their low conductivity likely precludes ***,the density of state calculations through density functional theory using hybrid HSE06 functional revealed overlapping electronic states at the Mg/MgO interface,which facilitates electron transfers and participates in redox *** determination of the hydrogen absorption energy at the Mg/MgO interface reveals it to be an excellent catalytic site,with HER being found to be a factor of 23x more efficient at the interface than on metallic *** results not only support the plausibility of the Mg/MgO interface being an effective cathode to the adjacent anodic Mg matrix during corrosion but also contribute to the understanding of the enhanced cathodic activities observed during the anodic dissolution of magnesium.

关键词： Magnesium Magnesium oxide Interface Hydrogen evolution DFT

Wireless sequential dual light delivery for programmed PDT in vivo

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Light(Science & Applications) 2024年第6期13卷 1047-1061页

作者： Jiayi Liu Bowen Sun Wenkai Li Han-Joon Kim Shu Uin Gan John S.Ho Juwita Norasmara Bte Rahmat Yong Zhang department of Oncology The Second Xiangya HospitalCentral South UniversityChangshaHunan410011China department of Biomedical engineering College of Design and EngineeringNational University of SingaporeSingapore117585Singapore department of mechanical engineering College of Design and EngineeringNational University of SingaporeSingapore117576Singapore department of Electrical and Computer engineering College of Design and EngineeringNational University of SingaporeSingapore117583Singapore department of Medical IT Convergence engineering Kumoh National Institute of TechnologyGumi39253Republic of Korea department of Surgery Yong Loo Lin School of MedicineNational University of SingaporeSingapore119228Singapore The N.1 Institute for Health National University of SingaporeSingapore117456Singapore Institute for Health Innovation and Technology National University of SingaporeSingapore119276Singapore department of Biomedical engineering College of EngineeringCity University of Hong KongKowloonHong Kong SARChina

Using photodynamic therapy(PDT)to treat deep-seated cancers is limited due to inefficient delivery of photosensitizers and low tissue penetration of *** nanocarriers are widely used for photosensitizer delivery,while the self-quenching of the encapsulated photosensitizers would impair the PDT ***,the generated short-lived reactive oxygen spieces(ROS)can hardly diffuse out of nanocarriers,resulting in low PDT ***,a smart nanocarrier system which can be degraded by light,followed by photosensitizer activation can potentially overcome these limitations and enhance the PDT efficacy.A light-sensitive polymer nanocarrier encapsulating photosensitizer(RB-M)was *** implantable wireless dual wavelength microLED device which delivers the two light wavelengths sequentially was developed to programmatically control the release and activation of the loaded *** transmitter coils with matching resonant frequencies allow activation of the connected LEDs to emit different wavelengths *** irradiation time,dose,and RB-M concentration were determined using an agent-based digital simulation *** vitro and in vivo validation experiments in an orthotopic rat liver hepatocellular carcinoma disease model confirmed that the nanocarrier rupture and sequential low dose light irradiation strategy resulted in successful PDT at reduced photosensitizer and irradiation dose,which is a clinically significant event that enhances treatment safety.

关键词： PDT overcome hardly

Battery pack capacity estimation for electric vehicles based on enhanced machine learning and field data

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Journal of Energy Chemistry 2024年第5期92卷 605-618页

作者： Qingguang Qi Wenxue Liu Zhongwei Deng Jinwen Li Ziyou Song Xiaosong Hu College of mechanical and Vehicle engineering Chongqing UniversityChongqing 400044China School of mechanical and Electrical engineering University of Electronic Science and Technology of ChinaChengdu 611731SichuanChina department of mechanical engineering National University of SingaporeSingapore 117575Singapore

Accurate capacity estimation is of great importance for the reliable state monitoring,timely maintenance,and second-life utilization of lithium-ion *** numerous works on battery capacity estimation using laboratory datasets,most of them are applied to battery cells and lack satisfactory fidelity when extended to real-world electric vehicle(EV)battery *** challenges intensify for large-sized EV battery packs,where unpredictable operating profiles and low-quality data acquisition hinder precise capacity *** fill the gap,this study introduces a novel data-driven battery pack capacity estimation method grounded in field *** proposed approach begins by determining labeled capacity through an innovative combination of the inverse ampere-hour integral,open circuit voltage-based,and resistance-based correction ***,multiple health features are extracted from incremental capacity curves,voltage curves,equivalent circuit model parameters,and operating temperature to thoroughly characterize battery aging behavior.A feature selection procedure is performed to determine the optimal feature set based on the Pearson correlation ***,a convolutional neural network and bidirectional gated recurrent unit,enhanced by an attention mechanism,are employed to estimate the battery pack capacity in real-world EV ***,the proposed method is validated with a field dataset from two EVs,covering approximately 35,000 *** results demonstrate that the proposed method exhibits better estimation performance with an error of less than 1.1%compared to existing *** work shows great potential for accurate large-sized EV battery pack capacity estimation based on field data,which provides significant insights into reliable labeled capacity calculation,effective features extraction,and machine learning-enabled health diagnosis.

关键词： Electricvehicle Lithium-ion battery pack Capacity estimation Machine learning Field data

Surface engineering with ionic polymers on membranes for boron removal

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Frontiers of Chemical Science and engineering 2024年第5期18卷 61-69页

作者： Xiting Zhang Chenyi Fang J Paul Chen Sui Zhang department of Chemical and Biomolecular engineering National University of SingaporeSingapore 117576Singapore department of Civil and Environmental engineering National University of SingaporeSingapore 119260Singapore College of Chemistry and Environmental engineering Shenzhen UniversityShenzhen 518060China

Removal of boric acid from seawater and wastewater using reverse osmosis membrane technologies is imperative and yet remains inadequately addressed by current commercial *** research efforts performed post-modification of reverse osmosis membranes to enhance boron rejection,which is usually accompanied by substantial sacrifice in water *** study delves into the surface engineering of low-pressure reverse osmosis membranes,aiming to elevate boron removal efficiency while maintaining optimal salt rejection and water *** were modified by the self-polymerization and co-deposition of dopamine and polystyrene sulfonate at varying ratios and *** surfaces became smoother and more hydrophilic after *** optimum membrane exhibited a water permeability of 9.2±0.1 L·m^(-2)·h^(-1)·bar^(-1),NaCl rejection of 95.8%±0.3%,and boron rejection of 49.7%±0.1% and 99.6%±0.3% at neutral and alkaline pH,*** water permeability is reduced by less than 15%,while the boron rejection is 3.7 times higher compared to the blank *** research provides a promising avenue for enhancing boron removal in reverse osmosis membranes and addressing water quality concerns in the desalination process.

关键词： membrane low-pressure reverse osmosis boron surface engineering

Mo_(2)B_(2)O_(2)MBene for Efficient Electrochemical CO Reduction to C_(2)Chemicals:Computational Exploration

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Energy & Environmental Materials 2024年第6期7卷 342-350页

作者： Bikun Zhang Jianwen Jiang department of Chemical and Biomolecular engineering National University of SingaporeSingapore 117576Singapore

Emerging as a new class of two-dimensional materials with atomically thin layers,MBenes have great potential for many important applications such as energy storage and *** mitigating carbon footprint,there has been increasing interest in CO_(2)/CO conversion on MBenes,but mostly focused on C_(1)products.C^(2+)chemicals generally possess higher energy densities and wider applications than C_(1)***,C–C coupling is technically challenging because of high energy requirement and currently few catalysts are suited for this ***,we explore electrochemical CO reduction reaction to C_(2)chemicals on Mo_(2)B_(2)O_(2)MBene via density-functional theory ***,the most favorable CO–COH coupling is revealed to be a spontaneous and barrierless process,making Mo_(2)B_(2)O_(2)an efficient catalyst for C–C *** C_(1)and C_(2)chemicals,ethanol is predicted to be the primary ***,by charge and bond analysis,it is unraveled that there exist significantly more unbonded electrons in the C atom of intermediate*COH than other C_(1)intermediates,which is responsible for the facile C–C *** an atomic scale,this work provides microscopic insight into C–C coupling process and suggests Mo_(2)B_(2)O_(2)a promising catalyst for electrochemical CO reduction to C_(2)chemicals.

关键词： C_(2)chemicals C-C coupling density-functional theory MBene Mo2B2O2

Data-driven prediction of dimensionless quantities for semi-infinite target penetration by integrating machine-learning and feature selection methods

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Defence Technology（防务技术） 2024年第10期40卷 105-124页

作者： Qingqing Chen Xinyu Zhang Zhiyong Wang Jie Zhang Zhihua Wang Institute of Applied Mechanics College of Mechanical and Vehicle EngineeringTaiyuan University of TechnologyTaiyuan 030024China Shanxi Key Lab.of Material Strength&structural Impact College of Mechanical and Vehicle EngineeringTaiyuan 030024China department of Civil and Environmental engineering National University of Singapore1 Engineering Drive 2117576Singapore

This study employs a data-driven methodology that embeds the principle of dimensional invariance into an artificial neural network to automatically identify dominant dimensionless quantities in the penetration of rod projectiles into semi-infinite metal targets from experimental *** derived mathematical expressions of dimensionless quantities are simplified by the examination of the exponent matrix and coupling relationships between feature *** a physics-based dimension reduction methodology,this way reduces high-dimensional parameter spaces to descriptions involving only a few physically interpretable dimensionless quantities in penetrating *** the relative importance of various dimensionless feature variables on the penetration efficiencies for four impacting conditions is evaluated through feature selection *** results indicate that the selected critical dimensionless feature variables by this synergistic method,without referring to the complex theoretical equations and aiding in the detailed knowledge of penetration mechanics,are in accordance with those reported in the ***,the determined dimensionless quantities can be efficiently applied to conduct semi-empirical analysis for the specific penetrating case,and the reliability of regression functions is validated.

关键词： Data-driven dimensional analysis Penetration Semi-infinite metal target Dimensionless numbers Feature selection

Phase-modulated multi-foci microscopy for rapid 3D imaging

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Photonics Research 2024年第7期12卷 1548-1555页

作者： WEIQI WANG LI GONG ZHIWEI HUANG Optical Bioimaging Laboratory Department of Biomedical EngineeringCollege of Design and EngineeringNational University of SingaporeSingapore 117576Singapore

3D imaging technology is pivotal in monitoring the functional dynamics and morphological alterations in living cells and ***,conventional volumetric imaging associated with mechanical z-scanning encounters challenges in limited 3D imaging speed with inertial ***,we present a unique phase-modulated multifoci microscopy (PM^(3)) technique to achieve snapshot 3D imaging with the advantages of extended imaging depths and adjustable imaging intervals between each focus in a rapid *** accomplish the tasks,we utilize a spatial light modulator (SLM) to encode the phases of the scattered or fluorescence light emanating from a volumetric sample and then project the multiple-depth images of the sample onto a single charge-coupled device camera for rapid 3D *** demonstrate that the PM^(3)technique provides~55-fold improvement in imaging depth in polystyrene beads phantom compared to the depth of field of the objective lens ***^(3)also enables the real-time monitoring of Brownian motion of fluorescent beads in water at a 15 Hz volume *** precisely manipulating the phase of scattered light on the SLM,PM^(3)can pinpoint the specific depth information in living zebrafish and rapidly observe the 3D dynamic processes of blood flow in the zebrafish *** work shows that the PM^(3)technique developed is robust and versatile for fast 3D dynamic imaging in biological and biomedical systems.

关键词： alterations scattered beads

Time-of-flight resolved stimulated Raman scattering microscopy using counter-propagating ultraslow Bessel light bullets generation

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Light(Science & Applications) 2024年第7期13卷 1427-1440页

作者： Shulang Lin Li Gong Zhiwei Huang Optical Bioimaging Laboratory Department of Biomedical EngineeringCollege of Design and EngineeringNational University of SingaporeSingapore 117576Singapore

We present a novel time-of-flight resolved Bessel light bullet-enabled stimulated Raman scattering(B2-SRS)microscopy for deeper tissue 3D chemical imaging with high resolution without a need for mechanical *** accomplish the tasks,we conceive a unique method to enable optical sectioning by generating the counterpropagating pump and Stokes Bessel light bullets in the sample,in which the group velocities of the Bessel light bullets are made ultraslow(e.g.,vg≈0.1c)and tunable by introducing programmable angular dispersions with a spatial light *** theoretically analyze the working principle of the collinear multicolor Bessel light bullet generations and velocity controls with the relative time-of-flight resolved detection for SRS 3D deep tissue *** have also built the B2-SRS imaging system and present the first demonstration of B2-SRS microscopy with Bessel light bullets for 3D chemical imaging in a variety of samples(e.g.,polymer bead phantoms,biological samples such as spring onion tissue and porcine brain)with high *** B2-SRS technique provides a>2-fold improvement in imaging depth in porcine brain tissue compared to conventional SRS *** method of optical sectioning in tissue using counter-propagating ultraslow Bessel light bullets developed in B2-SRS is generic and easy to perform and can be readily extended to other nonlinear optical imaging modalities to advance 3D microscopic imaging in biological and biomedical systems and beyond.

关键词： Bessel resolved propagating