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Particle Distribution Informed by Chain Rigidity in Diblock Copolymer Melts: The Effect of Entropy

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Chinese Journal of Polymer Science 2024年第3期42卷 388-399,I0009页

作者： Yuguo Chen Shuanhu Qi Ying Jiang School of Chemistry Beihang UniversityBeijing 100191China

We study the effect of chain rigidity on tailoring the nanoparticle locations for neutral and selective particles embedded in the lamellar morphology formed by semiflexible diblock copolymer chains using self-consistent field calculations. The nanoparticles are modeled through a cavity function, and the semiflexible chains are represented by the continuous Kratsky-Porod chain model. In general situation, the nanoparticles prefer to stay at the interface in order to reduce the interface areas and thus the system free energy. However, the particle distribution at the domain center is subtle, and the underlying physics is intrinsically different depending on the polymer flexibility. In the case of flexible chains, the entropy just contributes a constant shift to the free energy when the nanoparticles move around the domain center indicating that the local metastable state if appears at the domain center is wholly attributed to the local minimum in the enthalpy. If the polymers are rigid, the variation of the particle distribution at the domain center has a close relation with the polymer rigidity and nanoparticle size. In the case of strongly rigid polymers with small nanoparticles, a nearly uniform particle distribution at the domain center is observed, while in other cases, a local enhancement of particle distribution there is found. In contrast to the case of flexible chains, further analysis reveals the crucial role of entropy in controlling the shape of particle distributions at the phase domain. Specifically, the local metastable state appears in the domain center is determined by the large entropy there which arises from the weak coupling of bond orientations that allows the polymer chains to be relatively relaxed. When the particle becomes selective, its distribution in the phase domain exhibits a shift almost uniformly rather than changes its profile, and the underlying physics still holds. In all, our study establishes a strong coupling between the chain rigi

关键词： Semiflexible diblock copolymer Nanoparticle distribution Self-consistent field theory Entropic effect

CO_(2) hydrogenation to methanol over the copper promoted In_(2)O_(3) catalyst

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Journal of Energy Chemistry 2024年第6期93卷 135-145,I0004页

作者： Rui Zou Chenyang Shen Kaihang Sun Xinbin Ma Zhuoshi Li Maoshuai Li Chang-Jun Liu School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Collaborative Innovation Center of Chemical Science&Engineering Tianjin UniversityTianjin 300072China

The metal promoted In_(2)O_(3) catalysts for CO_(2) hydrogenation to methanol have attracted wide attention because of their high activity with high methanol ***,there was still no experimental confirmation if copper could be a good promoter for In_(2)O_(3).Herein,the Cu promoted In_(2)O_(3) catalyst was prepared using a deposition-precipitation *** prepared Cu/In_(2)O_(3) catalyst shows significantly higher CO_(2) conversion and space time yield(STY)of methanol,compared to the un-promoted In_(2)O_(3) *** loading of Cu facilitates the activation of both H_(2) and CO_(2) with the interface between the Cu cluster and defective In_(2)O_(3) as the active *** Cu/In_(2)O_(3) catalyst takes the CO hydrogenation pathway for methanol synthesis from CO_(2) *** exhibits a unique size effect on the CO *** temperatures below 250℃,CO adsorption on Cu/In_(2)O_(3) is stronger than that on In_(2)O_(3),causing higher methanol *** increasing temperatu res,the Cu catalyst aggregates,which leads to the formation of weak CO adsorption site and causes a decrease in the methanol *** with other metal promoted In_(2)O_(3) catalysts,it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.

关键词： CO_(2)hydrogenation Methanol Cu In_(2)O_(3) CO Selectivity DFT

Implantable Electrochemical Microsensors for In Vivo Monitoring of Animal Physiological Information

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Nano-Micro Letters 2024年第3期16卷 183-211页

作者： Jin Zhou Shenghan Zhou Peidi Fan Xunjia Li Yibin Ying Jianfeng Ping Yuxiang Pan Laboratory of Agricultural Information Intelligent Sensing College of Biosystems Engineering and Food ScienceZhejiang UniversityHangzhou 310058People’s Republic of China ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou 311200People’s Republic of China

In vivo monitoring of animal physiological information plays a crucial role in promptly alerting humans to potential diseases in animals and aiding in the exploration of mechanisms underlying human ***,implantable electrochemical microsensors have emerged as a prominent area of *** microsensors not only fulfill the technical requirements for monitoring animal physiological information but also offer an ideal platform for *** have been extensively studied for their ability to monitor animal physiological information in a minimally invasive manner,characterized by their bloodless,painless features,and exceptional *** development of implantable electrochemical microsensors for in vivo monitoring of animal physiological information has witnessed significant scientific and technological advancements through dedicated *** review commenced with a comprehensive discussion of the construction of microsensors,including the materials utilized and the methods employed for *** this,we proceeded to explore the various implantation technologies employed for electrochemical *** addition,a comprehensive overview was provided of the various applications of implantable electrochemical microsensors,specifically in the monitoring of diseases and the investigation of disease ***,a concise conclusion was conducted on the recent advancements and significant obstacles pertaining to the practical implementation of implantable electrochemical microsensors.

关键词： Electrochemical microsensors Implantable sensors In vivo monitoring Animal physiological information

Finite-time Prescribed Performance Time-Varying Formation Control for Second-Order Multi-Agent Systems With Non-Strict Feedback Based on a Neural Network Observer

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1039-1050页

作者： Chi Ma Dianbiao Dong the School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China

This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown *** eliminate nonlinearities,neural networks are applied to approximate the inherent dynamics of the *** addition,due to the limitations of the actual working conditions,each follower agent can only obtain the locally measurable partial state information of the leader *** address this problem,a neural network state observer based on the leader state information is ***,a finite-time prescribed performance adaptive output feedback control strategy is proposed by restricting the sliding mode surface to a prescribed region,which ensures that the closed-loop system has practical finite-time stability and that formation errors of the multi-agent systems converge to the prescribed performance bound in finite ***,a numerical simulation is provided to demonstrate the practicality and effectiveness of the developed algorithm.

关键词： Finite-time control multi-agent systems neural network prescribed performance control time-varying formation control

Regression Method for Rail Fastener Tightness Based on Center-Line Projection Distance Feature and Neural Network

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 356-371页

作者： Yuanhang Wang Duxin Liu Sheng Guo Yifan Wu Jing Liu Wei Li Hongjie Wang Robotics research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China china Construction Industrial&Energy Engineering Group Co. Ltd.Nanjing 210023China

In the railway system,fasteners have the functions of damping,maintaining the track distance,and adjusting the track ***,routine maintenance and inspection of fasteners are important to ensure the safe operation of track ***,assessment methods for fastener tightness include manual observation,acoustic wave detection,and image *** are limitations such as low accuracy and efficiency,easy interference and misjudgment,and a lack of accurate,stable,and fast detection *** at the small deformation characteristics and large elastic change of fasteners from full loosening to full tightening,this study proposes high-precision surface-structured light technology for fastener detection and fastener deformation feature extraction based on the center-line projection distance and a fastener tightness regression method based on neural ***,the method uses a 3D camera to obtain a fastener point cloud and then segments the elastic rod area based on the iterative closest point algorithm *** component analysis is used to calculate the normal vector of the segmented elastic rod surface and extract the point on the centerline of the elastic *** point is projected onto the upper surface of the bolt to calculate the projection ***,the mapping relationship between the projection distance sequence and fastener tightness is established,and the influence of each parameter on the fastener tightness prediction is ***,by setting up a fastener detection scene in the track experimental base,collecting data,and completing the algorithm verification,the results showed that the deviation between the fastener tightness regression value obtained after the algorithm processing and the actual measured value RMSE was 0.2196 mm,which significantly improved the effect compared with other tightness detection methods,and realized an effective fastener tightness regression.

关键词： Railway system Fasteners Tightness inspection Neural network regression 3D point cloud processing

Advanced electrospinning nanomaterials:From spinning fabrication techniques to electrochemical applications

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Nano research 2024年第8期17卷 7077-7116页

作者： Jie Zhang Miao Yu Shuhui Tao College of Materials Science and Engineering Sichuan UniversityChengdu 610065China School of Mechanical Engineering Sichuan UniversityChengdu 610065China National University of Singapore(Chongqing)research Institute Chongqing 401123China

Fuel cells,rechargeable metal–air batteries,metal-ion batteries,and supercapacitors have been regarded as prospective energy sources technologies to replace the fossil ***,electrochemical sensors also have been successfully developed as promising platforms for detecting pollutants,drug analysis,and healthcare *** is a scalable and suitable technique to design and fabricate diverse nanofibers and their nanocomposites for key components in electrochemical ***,a comprehensive review of electrospinning,from the technological innovations to the novel electrospun composite nanofibers,is *** importantly,the recent advances on the diverse components of electrochemical devices are highlighted,followed with the detailed discussion about the corresponding enhancement mechanism based on the electrospun ***,the currently faced challenges on the fabrication of electrospun nanomaterials are raised and a brief perspective for the future development of electrospun nanomaterials-based electrochemical applications is prospected.

关键词： electrospinning carbon nanofibers metal-organic frameworks electrode materials electrochemical applications

Biological Interaction and Imaging of Ultrasmall Gold Nanoparticles

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Nano-Micro Letters 2024年第3期16卷 69-98页

作者： Dongmiao Sang Xiaoxi Luo Jinbin Liu Key Laboratory of Functional Molecular Engineering of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640People’s Republic of China

Ultrasmall gold nanoparticles(AuNPs)typically includes atomically precise gold nanoclusters(AuNCs)and AuNPs with a core size below 3 *** as a bridge between small molecules and traditional inorganic nanoparticles,the ultrasmall AuNPs show the unique advantages of both small molecules(e.g.,rapid distribution,renal clearance,low non-specific organ accumulation)and nanoparticles(e.g.,long blood circulation and enhanced permeability and retention effect).The emergence of ultrasmall AuNPs creates significant opportunities to address many challenges in the health field including disease diagnosis,monitoring and *** the nano–bio interaction dictates the overall biological applications of the ultrasmall AuNPs,this review elucidates the recent advances in the biological interactions and imaging of ultrasmall *** begin with the introduction of the factors that influence the cellular interactions of ultrasmall *** then discuss the organ interactions,especially focus on the interactions of the liver and *** further present the recent advances in the tumor interactions of ultrasmall *** addition,the imaging performance of the ultrasmall AuNPs is summarized and ***,we summarize this review and provide some perspective on the future research direction of the ultrasmall AuNPs,aiming to accelerate their clinical translation.

关键词： Ultrasmall gold nanoparticle Cellular interaction Organ interaction Tumor interaction Bioimaging

Experimental and numerical study of combustion characteristics of ammonia-hydrogen-air swirling flame with/without secondary air injection

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Chinese Journal of Aeronautics 2024年第4期37卷 243-255页

作者： Chunyu LIU Chenhu GAO Yue HUANG Hua JIN Dan ZHAO Wenjiang XU Yancheng YOU School of Aerospace Engineering Xiamen UniversityXiamen 361005China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering University of CanterburyChristchurch 8041New Zealand

Ammonia (NH_(3)) is currently considered to be a potential carbon-free alternative fuel,and its large-scale use as such would certainly decrease greenhouse gas emissions and meet increasingly stringent emission *** the low flame propagation speed and high NO production of NH_(3) hinder its direct application as a renewable fuel,co-combustion of NH_(3)–H_(2)is an effective way to overcome these *** this study,the combustion characteristics of NH_(3)–H_(2)swirling flames under different equivalence ratios and H_2blending ratios conditions are both numerically and experimentally ***,the One-Dimensional (1D) laminar flame computation presents a comparison base and the Three-Dimensional (3D) numerical simulation yields detailed flame property ***,the high-speed camera takes instantaneous swirl flame images and the gas analyzer measures the NO emission at the exit plane of the flame *** and quantitative analysis is performed on the flame structure and NO emission for a series of NH_(3)–H_(2)swirl *** variation trends of the NO emission calculated using different techniques agree very *** quantitative results show that the NO emissions are much higher at lean equivalence ratios than those at rich equivalence ratios,and such difference is closely related to the combustion flame ***,it is shown that the utilization of secondary air injection can achieve a significant reduction in NO emissions at the exit of the combustion chamber at equivalence ratios less than or equal to 0.9.

关键词： Ammonia combustion Swirling flow NO emission characteristics Secondary combustion Chemical reaction mechanism

Synthesis of atomically dispersed cationic nickel-confined mesoporous ZSM-48(ANMZ-48)directed by metal complexes in amphiphilic molecules

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Science china Chemistry 2024年第1期67卷 343-350页

作者： Yu Chen Quanzheng Deng Yiru Mao Yuxi Fang Zhihua Cao Honggen Peng Shunai Che Lu Han School of Chemical Science and Engineering Tongji UniversityShanghai 200092China School of Chemistry and Chemical Engineering Nanchang UniversityNanchang 330031China School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Resources and Environment Nanchang UniversityNanchang 330031China State Key Laboratory of Metal Matrix Composites Shanghai Key Laboratory for Molecular Engineering of Chiral DrugsShanghai Jiao Tong UniversityShanghai 200240China

The synthesis of mesoporous zeolite-anchored atomically dispersed metal catalysts(ADCs)is a considerable challenge in chemistry and materials *** we report the synthesis of atomically dispersed cationic nickel-confined mesoporous ZSM-48(ANMZ-48)by in situ hydrothermal reaction employing a designed tri-functional metal complex template,by which the triquaternary ammonium groups in the hydrophilic region direct the formation of ZSM-48 zeolite;the aromatic groups in the hydrophobic tail generate the mesopores through π-π stacking;and the complexes formed by nickel ions coordinated with terpyridyl groups generate atomically dispersed Ni2+confined in zeolite frameworks due to the strong sintering resistance generated by the strong coordination *** ANMZ-48 is consisting of stacking of sheet-like ZSM-48 domains connected by multiply crystal twinning sharing the common(011)plane,generating abundant of imbedded mesopores with the uniform thickness of~2.4 nm and with the width of 10-50 *** excellent catalytic activity and stability of ANMZ-48 were also reflected in the dry reforming of methane(DRM)reaction.

关键词： atomically dispersed catalyst mesoporous zeolite ZSM-48 in situ hydrothermal synthesis the dry reforming of methane reaction