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Time-dependent deviation of bridge pile foundations caused by adjacent large-area surcharge loads in soft soils and its preventive measures

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Frontiers of Structural and Civil engineering 2024年第2期18卷 184-201页

作者： Shuanglong LI Limin WEI Jingtai NIU Zhiping DENG Bangbin WU Wuwen QIAN Feifei HE school of Hydraulic engineering Nanchang Institute of TechnologyNanchang 330099China school of Civil engineering Central South UniversityChangsha 410075China

Time-dependent characteristics(TDCs)have been neglected in most previous studies investigating the deviation mechanisms of bridge pile foundations and evaluating the effectiveness of preventive measures.In this study,the stress-strain-time characteristics of soft soils were illustrated by consolidation-creep tests based on a typical engineering case.An extended Koppejan model was developed and then embedded in a finite element(FE)model via a user-material subroutine(UMAT).Based on the validated FE model,the time-dependent deformation mechanism of the pile foundation was revealed,and the preventive effect of applying micropiles and stress-release holes to control the deviation was investigated.The results show that the calculated maximum lateral displacement of the cap differs from the measured one by 6.5%,indicating that the derived extended Koppejan model reproduced the deviation process of the bridge cap-pile foundation with time.The additional load acting on the pile side caused by soil lateral deformation was mainly concentrated within the soft soil layer and increased with the increase in load duration.Compared with t=3 d(where t is surcharge time),the maximum lateral additional pressure acting on Pile 2#increased by approximately 47.0%at t=224 d.For bridge pile foundation deviation in deep soft soils,stress-release holes can provide better prevention compared to micropiles and are therefore recommended.

关键词： bridge pile foundation surcharge load soft soil time-dependent deformation interaction mechanism preventive measure

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Appreciable Enhancement of Photocatalytic Performance for N-doped SrMoO_(4) via the Vapor-thermal Method

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 24-31页

作者：恽志强戴振翔 ZHU Liwei ZHENG Ganhong school and Materials Science and engineering Anhui UniversityHefei 230601China school of Physics and Optoelectronics engineering Anhui UniversityHefei 230601China

A series of nitrogen-doped SrMoO_(4) with different Sr/N mole ratio (R=0,0.05,0.10,0.15,0.20,0.40,and 0.60) were synthesized using urea as the N source via the vapor-thermal method.The photocatalytic degradation ability of all samples was evaluated using methylene blue (MB) as a target contaminant.The band gaps of N-doped samples are all higher than that of pristine ones,which is only 3.12 eV.BET specific surface area S_(BET) and pore volume are increased due to the N doping.And the greater increase of S_(BET),the faster the photodegradation speed of methylene blue on SrMoO_(4).More specifically,the degradation efficiency of MB is improved up to 87%in 100 min.

关键词： SrMoO_(4) photocatalytic property nitrogen element doping

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Investigation of Ce/BEA as a passive NOx adsorber:1.The occurrences of cerium and adsorption behavior

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Journal of Rare Earths 2024年第7期42卷 1265-1271页

作者： Minghui Yu Yiying Ding Xiaojie Yu Siwei Yan Meiqing Shen Jianqiang Wang Jun Wang Gurong Shen school of Materials Science and engineering Tianjin University school of Chemical engineering and Technology Tianjin University National Rare Earth Catalysis Research Institute

Ce/BEA has great potential as a passive NOxabsorber（PNA） to reduce the NOxemissions during the cold start phase especially in diesel engine for its high resistance to CO and suitable NOxdesorption temperature range.However,as a novel material,its physical and chemical properties still remain unknown.In this work,Ce/BEA was synthesized by ion-exchange method to identify the active species in NOxadsorption,compared with aggregated Ce species in Ce/SiAlOxprepared by impregnation method.X-ray diffraction（XRD）,high resolution-transmission electron microscopy（HR-TEM） and aberration-correctedscanning transmission electron microscopy（AC-STEM） were performed to confirm the isolated single atom formation of Ce species in Ce/BEA.UV-vis diffraction reflection spectra（DRS） and X-ray photoelectron spectroscopy（XPS） were conducted to find the difference of chemical environment between the isolated Ce species and aggregated ones.PNA performance evaluation and temperature programmed reduction of hydrogen（H2-TPR） results show the high NOxstorage capacity and active oxygen species quantity in Ce/BEA.It is also found that the main NOxadsorption species are Ce4+-O*rather than Ce3+.NOx-diffuse reflectance infrared Fourier transform spectroscopy（NOx-DRIFTS） confirms that the bidentate nitrite species are the critical NOxadsorption intermediates and the conception of NOxadsorption and desorption processes is proposed.

关键词： Ce/BEA Isolated Ce species Passive NOx absorber Rare earths

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Liquid metal biomaterials: translational medicines,challenges and perspectives

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National Science Review 2024年第2期11卷 264-284页

作者： Hanchi Xu Jincheng Lu Yikuang Xi Xuelin Wang Jing Liu Department of Biomedical engineering School of Medicine Tsinghua University Beijing Tsinghua Changgung Hospital School of Clinical Medicine Tsinghua University Shanghai World Foreign Language Academy Beijing Advanced Innovation Center for Biomedical engineering School of Engineering MedicineBeihang University Beijing Key Lab of Cryo-Biomedical engineering and Key Lab of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences

Until now, significant healthcare challenges and growing urgent clinical requirements remain incompletely addressed by presently available biomedical materials. This is due to their inadequate mechanical compatibility, suboptimal physical and chemical properties, susceptibility to immune rejection, and concerns about long-term biological safety. As an alternative, liquid metal(LM) opens up a promising class of biomaterials with unique advantages like biocompatibility, flexibility, excellent electrical conductivity,and ease of functionalization. However, despite the unique advantages and successful explorations of LM in biomedical fields, widespread clinical translations and applications of LM-based medical products remain limited. This article summarizes the current status and future prospects of LM biomaterials, interprets their applications in healthcare, medical imaging, bone repair, nerve interface, and tumor therapy, etc.Opportunities to translate LM materials into medicine and obstacles encountered in practices are discussed.Following that, we outline a blueprint for LM clinics, emphasizing their potential in making new-generation artificial organs. Last, the core challenges of LM biomaterials in clinical translation, including bio-safety,material stability, and ethical concerns are also discussed. Overall, the current progress, translational medicine bottlenecks, and perspectives of LM biomaterials signify their immense potential to drive future medical breakthroughs and thus open up novel avenues for upcoming clinical practices.

关键词： liquid metal biomaterials translational medicine clinical device healthcare therapeutics

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Research of caged dynamics of clusters center atoms in Pd_(82)Si_(18) amorphous alloy

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Chinese Physics B 2024年第4期33卷 623-629页

作者：邓永和陈贝祁清华李兵兵高明文大东王小云彭平 school of Computational Science and Electronics Hunan Institute of EngineeringXiangtan 411104China school of Physics and Mechanical&Electrical engineering Jishou UniversityJishou 416000China school of Materials Science and engineering Hunan UniversityChangsha 410082China

To date,there is still a lack of a comprehensive explanation for caged dynamics which is regarded as one of the intricate dynamic behaviors in amorphous alloys.This study focuses on Pd_(82)Si_(18)as the research object to further elucidate the underlying mechanism of caged dynamics from multiple perspectives,including the cage's lifetime,atomic local environment,and atomic potential energy.The results reveal that Si atoms exhibit a pronounced cage effect due to the hindrance of Pd atoms,resulting in an anomalous peak in the non-Gaussian parameters.An in-depth investigation was conducted on the caged dynamics differences between fast and slow Si atoms.In comparison to fast Si atoms,slow Si atoms were surrounded by more Pd atoms and occupied lower potential energy states,resulting in smaller diffusion displacements for the slow Si atoms.Concurrently,slow Si atoms tend to be in the centers of smaller clusters with coordination numbers of 9 and 10.During the isothermal relaxation process,clusters with coordination numbers 9 and 10 have longer lifetimes,suggesting that the escape of slow Si atoms from their cages is more challenging.The findings mentioned above hold significant implications for understanding the caged dynamics.

关键词： caged dynamics Pd_(82)Si_(18) amorphous alloy fast and slow atoms clusters lifetime

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Deterministic and Robust Volt-var Control Methods of Power System Based on Convex Deep Learning

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 719-729页

作者： Qing Ma Changhong Deng IEEE the school of Electrical engineering and Automation Wuhan University

Volt-var control(VVC) is essentially a non-convex optimization problem due to the non-convexity of power flow(PF) constraints, resulting in the difficulty in obtaining the optimum without convexity conversion. The existing second-order cone method for the convexity conversion often leads to a sharp increase in PF constraints and optimization variables, which in turn increases the optimization difficulty or even leads to optimization failure. This paper first proposes a deterministic VVC method based on convex deep learning power flow(DLPF). This method uses the input convex neural network(ICNN) to establish a single convex mapping between state parameters and node voltage to complete the convexity conversion while the optimization variables only correspond to reactive power equipment, which can ensure the global optimum with extremely fast computation speed. To cope with the impact brought by the uncertainty of distributed energy and omit the additional worst scenario search of traditional robust VVC, this paper proposes robust VVC method based on convex deep learning interval power flow(DLIPF), which continues to adopt ICNN to establish another convex mapping between state parameters and node voltage interval. Combining DLIPF with DLPF, this method decreases the modeling and optimization difficulty of robust VVC significantly. Test results on 30-bus, 118-bus, and 200-bus systems prove the correctness and rapidity of the proposed methods.

关键词： Optimization Reactive power Mathematical models Deep learning Uncertainty Load flow Programming

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Coordinated Dispatch Based on Distributed Robust Optimization for Interconnected Urban Integrated Energy and Transmission Systems

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 840-851页

作者： Wei Xu Yufeng Guo Tianhui Meng Yingwei Wang Jilai Yu the school of Electrical engineering and Automation Harbin Institute of Technology

To improve the economic efficiency of urban integrated energy systems(UIESs) and mitigate day-ahead dispatch uncertainty, this paper presents an interconnected UIES and transmission system(TS) model based on distributed robust optimization. First, interconnections are established between a TS and multiple UIESs, as well as among different UIESs, each incorporating multiple energy forms. The Bregman alternating direction method with multipliers(BADMM) is then applied to multi-block problems, ensuring the privacy of each energy system operator(ESO). Second, robust optimization based on wind probability distribution information is implemented for each ESO to address dispatch uncertainty. The column and constraint generation(C&CG) algorithm is then employed to solve the robust model. Third, to tackle the convergence and practicability issues overlooked in the existing studies, an external C&CG with an internal BADMM and corresponding acceleration strategy is devised. Finally, numerical results demonstrate that the adoption of the proposed model and method for absorbing wind power and managing its uncertainty results in economic benefits.

关键词： Heating systems Convex functions Optimization Uncertainty Pipelines Distributed algorithms Convergence

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Role of micro-Ca/In alloying in tailoring the microstructural characteristics and discharge performance of dilute Mg-Bi-Sn-based alloys as anodes for Mg-air batteries

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Journal of Magnesium and Alloys 2024年第1期12卷 251-266页

作者： Fei-er Shangguan Wei-li Cheng Yu-hang Chen Ze-qin Cui Hui Yu Hong-xia Wang Li-fei Wang Hang Li Hua Hou school of Materials Science and engineering Taiyuan University of TechnologyTaiyuan 030024China school of Materials Science and engineering Hebei University of TechnologyTianjin 300132China school of Materials Science and engineering North University of ChinaTaiyuan 030051China

The influence of micro-Ca/In alloying on the microstructural charac teristics,electrochemical behaviors and discharge properties of extruded dilute Mg-0.5Bi-0.5Sn-based(wt.%)alloys as anodes for Mg-air batteries are evaluated.The grain size and texture intensity of the Mg-Bi-Sn-based alloys are significantly decreased after the Ca/In alloying,particularly for the In-containing alloy.Note that,in addition to nanoscale Mg_(3)Bi_(2)phase,a new microscale Mg_(2)Bi_(2)Ca phase forms in the Ca-containing alloy.The electrochemical test results demonstrate that Ca/In micro-alloying can enhance the electrochemical activity.Using In to alloy the Mg-Bi-Sn-based alloy is effective in restricting the cathodic hydrogen evolution(CHE)kinetics,leading to a low self-corrosion rate,while severe CHE occurred after Ca alloying.The micro-alloying of Ca/In to Mg-Bi-Sn-based alloy strongly deteriorates the compactness of discharge products film and mitigates the"chunk effect"(CE),hence the cell voltage,anodic efficiency as well as discharge capacity are greatly improved.The In-containing alloy exhibits outstanding discharge performance under the combined effect of the modified microstructure and discharge products,thus making it a potential anode material for primary Mg-air battery.

关键词： Mg-air batteries Mg-Bi-Sn based alloys Electrochemical behaviors Discharge properties

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Migration and transformation of Pb,Cu,and Zn during co-combustion of high-chlorine-alkaline coal and Si/Al dominated coal

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Journal of Environmental Sciences 2024年第7期141卷 26-39页

作者： Jiangze Luo Qiwei Yang Jianqiao Wang Boxiong Shen Zhuozhi Wang Qiqi Shi Zhong Zhao Chao Huang Jie Xu Tianjin Key Laboratory of Clean Energy and Pollution Control School of Energy and Environmental EngineeringHebei University of TechnologyTianjin 300103China school of Chemical engineering Hebei University of TechnologyTianjin 300103China

Shaerhu(SEH)coal is abundant in Xinjiang,China.The utilization of SEH suffers from severe ash deposition,slagging,and fouling problems due to its high-chlorine-alkaline characteristics.The co-combustion of high-alkaline coal and other type coals containing high Si/Al oxides has been proven to be a simple and effective method that will alleviate ash-related problems,but the risk of heavy metals(HMs)contamination in this process is nonnegligible.Hence,the volatilization rates and chemical speciation of Pb,Cu,and Zn in co-combusting SEH and a high Si/Al oxides coal,i.e.,Yuanbaoshan(YBS)coal were investigated in this study.The results showed that the addition of SEH increased the volatilization rates of Pb,Cu,and Zn during the co-combustion at 800℃from 23.70%,23.97%,and 34.98%to 82.31%,30.01%,and 44.03%,respectively,and promoted the extractable state of Cu and Zn.In addition,the interaction between SEH and YBS inhibited the formation of the Pb residue state.SEM-EDS mapping results showed that compared to Zn and Cu,the signal intensity of Pb was extremely weak in regions where some of the Si and Al signal distributions overlap.The DFT results indicated that the O atoms of the metakaolin(Al_(2)O_(3)·2SiO_(2))(001)surface were better bound to the Zn and Cu than Pb atoms after adsorption of the chlorinated HMs.These results contribute to a better understanding of the effects of high-alkaline coal blending combustion on Pb,Cu,and Zn migration and transformation.

关键词： Heavy metals High-chlorine-alkaline coal Coal blending combustion Density functional theory

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Visible Light Indoor Positioning System Based on Pisarenko Harmonic Decomposition and Neural Network

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Chinese Journal of Electronics 2024年第1期33卷 195-203页

作者： Li ZHAO Yi REN Qi WANG Lange DENG Feng ZHANG school of Electronic Information engineering Xi’an Technological University

Visible-light indoor positioning is a new generation of positioning technology that can be integrated into smart lighting and optical communications. The current received signal strength(RSS)-based visible-light positioning systems struggle to overcome the interferences of background and indoor-reflected noise. Meanwhile, when ensuring the lighting, it is impossible to use the superposition of each light source to accurately distinguish light source information; furthermore, it is difficult to achieve accurate positioning in complex indoor environments. This study proposes an indoor positioning method based on a combination of power spectral density detection and a neural network. The system integrates the mechanism for visible-light radiation detection with RSS theory, to build a back propagation neural network model fitting for multiple reflection channels. Different frequency signals are loaded to different light sources at the beacon end, and the characteristic frequency and power vectors are obtained at the location end using the Pisarenko harmonic decomposition method. Then, a complete fingerprint database is established to train the neural network model and conduct location tests. Finally, the location effectiveness of the proposed algorithm is verified via actual positioning experiments. The simulation results show that, when four groups of sinusoidal waves with different frequencies are superimposed with white noise, the maximum frequency error is 0.104 Hz and the maximum power error is 0.0362 W. For the measured positioning stage, a 0.8 m × 0.8 m × 0.8 m solid wood stereoscopic positioning model is constructed, and the average error is 4.28 cm. This study provides an effective method for separating multi-source signal energies, overcoming background noise, and improving indoor visible-light positioning accuracies.

关键词： Visible-light communication Indoor positioning Frequency estimation Pisarenko harmonic decomposition Back propagation neural network

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