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Chain Dynamics Heterogeneity in Plasticized Poly(vinyl butyral)(PVB) as Elucidated by Solid-State NMR

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Chinese Journal of Polymer Science 2024年第1期42卷 113-124,I0010页

作者： jing Lv Xu chen Zi-Shuo Wu Ya-Hui Li Wei chen National Synchrotron Radiation Laboratory Anhui Provincial Engineering Laboratory of Advanced Functional Polymer FilmCAS Key Laboratory of Soft Matter ChemistryUniversity of Scienceand Technology of ChinaHefei 230026China

The chain dynamics heterogeneity of the poly(vinyl butyral)(PVB) plasticized by triethylene glycol bis(2-ethylhexa noate)(TEG-EH) was investigated by various solid-state NMR *** plasticized PVB shows two domains in distinct molecular dynamics differences,namely,rigid and soft domains,where the latter is the plasticizer-rich *** time domain low field NMR was first used to investigate the dynamics heterogeneity of the plasticized PVB,and the results show the decreasing activated energy of components in the soft domain of plasticized PVB(E_a=20.2 kJ/mol) as compared with that of the pristine one(E_a=24.3 kJ/mol).Detailed dynamics heterogeneity was obtained by high-field NMR with site-specific *** quadrupole-echo ~2H-NMR was adopted to elucidate the dynamics heterogeneity of the vinyl alcohol(VA) units,where only the hydroxyl group of VA is *** ~1H-^(13)C WISE NMR spectra show that there is not much difference in the mobility of the VB unit in PVB with and without plasticizer,whereas the glass transition temperature differed by approximately 53℃.This is further supported by Torchia's T_1 relaxation *** origin of such an unusual phenomenon is attributed to the critical role of the remaining VA(~22%) in the soft domain,where the VA units locally aggregate through hydrogen ***,the existence of a mobility gradient in the VB unit has been ***,the mobility difference for VB with different stereo-geometry(meso or racemic conformation) is observed for the first *** indicates the importance of modulating the ratio of meso over racemic VB for controlling the macroscopic perfo rmance of PVB.

关键词： Poly(vinyl butyral) Dynamics heterogeneity Plasticizer Solid state NMR

Transitional Revenue Scheme for High-cost Generator Unit in Guangdong Electricity Market Based on Government Authorized Contracts

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 208-221页

作者： Jisong Zhu Baike chen Tianyao Ji Zhaoxia jing School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China

High-cost generator units are at a cost disadvantage in electricity spot *** study focuses on revenue mechanisms of gas-fired units affected by power market reform in Guangdong province,*** the first time,we compare impacts on market indicators of five settlement mechanisms:feed-in tariff(FiT),location marginal price(LMP),contract for difference(CFD),direct subsidy(DS),and estimated revenue method(ERM).In particular,we design key parameters,including authorized CFD and ERM of two kinds of government authorized contracts based on traditional dispatching patterns to avoid significant profit fluctuations brought by market *** also analyze impact of factors such as climbing performance,seasonal load,and subsidy amount on the overall market and its *** of a case study show to directly subsidize gasfired units will lead higher-cost units to generate more electricity,with a resulting loss of social *** of market prices and provision of unreasonable incentives are fatal disadvantages of this subsidy *** government and policymakers should consider financial means to adjust benefits to reduce production costs and increase social ***,by case analysis,the ERM shows its stable performance in revenue of high-cost units,while we find that authorized CFD is not applicable for gas-fired units whose output is unstable as a marginal unit ***,we suggest government agencies adopt ERM to sign contracts with gas-fired units,to attain a balance between fairness and efficiency.

关键词： Guangdong electricity market high-cost generator unit settlement mechanism subsidy

The clinical antiprotozoal drug nitazoxanide and its metabolite tizoxanide extend Caenorhabditis elegans lifespan and healthspan

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Acta Pharmaceutica Sinica B 2024年第7期14卷 3266-3280页

作者： Wenfeng Li Shuming chen jing Lang jing Luo Jiahui chen Liping Zhang Zhijie Sun Deli Dong Department of Pharmacology China Pharmaceutical UniversityNanjing 210009China

The drugs extending healthspan in clinic have always been *** is an FDA-approved clinical antiprotozoal *** is rapidly metabolized to tizoxanide after absorption in *** previous studies find that nitazoxanide and its metabolite tizoxanide induce mild mitochondrial uncoupling and activate cellular AMPK,oral nitazoxanide protects against experimental hyperlipidemia,hepatic steatosis,and ***,we demonstrate that both nitazoxanide and tizoxanide extend the lifespan and healthspan of Caenorhabditis elegans through Akt/AMPK/sir 2.1/daf16 ***,both nitazoxanide and tizoxanide improve high glucose-induced shortening of *** *** has been a clinical drug with a good safety profile,we suggest that it is a novel anti-aging drug.

关键词： Nitazoxanide Tizoxanide C.elegans Healthspan Lifespan AMPK Akt Mitochondrial uncoupling

Numerical Analysis of Cold-Formed Thin-Walled Steel Short Columns with Pitting Corrosion during Bridge Construction

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Structural Durability & Health Monitoring 2024年第2期18卷 181-196页

作者： Hongzhang Wang jing Guo Shanjun Yang Chaoheng cheng jing chen Zhihao chen CCCC Second Harbor Engineering Third Engineering Co. Ltd.Zhenjiang212000China Suqian Highway Development Center Suqian223800China School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou221116China

Pitting corrosion is harmful during bridge construction,which will lead to uneven roughness of steel surfaces and reduce the thickness of ***,the effect of pitting corrosion on the mechanical properties of cold-formed thin-walled steel stub columns is studied,and the empirical formulas are established through regression fitting to predict the ultimate load of web and flange under pitting *** detail,the failure modes and load-displacement curves of specimens with different locations,area ratios,and depths are obtained through a large number of non-linear finite element *** for the specimens with pitting corrosion on the web,all the specimens are subject to local buckling failure,and the failure mode will not change with pitting corrosion,but the failure location will change with pitting corrosion location;the size,location,and area ratio of pitting corrosion have little influence on the ultimate load of cold-formed thin-walled steel short columns,but the loss rate of pitting corrosion section area has a greater impact on the ultimate bearing *** for the specimen with flange pitting corrosion,the location and area ratio of pitting corrosion have less influence on the ultimate load of cold-formed thin-walled steel short columns,and the section area loss rate has greater influence on the ultimate bearing capacity;the impact of web pitting corrosion on the ultimate load is greater than that of flange pitting corrosion under the same condition of pitting corrosion section *** prediction formulas of limit load which are suitable for pitting corrosion of web and flange are established,which can provide a reference for performance evaluation of corroded cold-formed thin-walled steel.

关键词： Pitting corrosion cold-formed thin-walled steel ultimate load prediction formula short columns

Efficient conversion of acoustic vortex using extremely anisotropic metasurface

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Frontiers of physics 2024年第4期19卷 257-264页

作者： Zhanlei Hao Haojie chen Yuhang Yin cheng-Wei qiu Shan Zhu Huanyang chen Institute of Electromagnetics and Acoustics and Department of Physics College of Physical Science and TechnologyXiamen UniversityXiamen 361005China Department of Electrical and Computer Engineering National University of Singapore4 Engineering Drive 3117583Singapore Department of Mechanical and Electrical Engineering Xiamen UniversityXiamen 361005China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China

Vortex wave and plane wave,as two most fundamental forms of wave propagation,are widely applied in various research ***,there is currently a lack of basic mechanism to enable arbitrary conversion between *** this paper,we propose a new paradigm of extremely anisotropic acoustic metasurface(AM)to achieve the efficient conversion from 2D vortex waves with arbitrary orbital angular momentum(OAM)to plane *** underlying physics of this conversion process is ensured by the symmetry shift of AM medium parameters and the directional compensation of ***,this novel phenomenon is further verified by analytical calculations,numerical demonstrations,and acoustic experiments,and the deflection angle and direction of the converted plane waves are qualitatively and quantitatively confirmed by a simple *** work provides new possibilities for arbitrary manipulation of acoustic vortex,and holds potential applications in acoustic communication and OAM-based devices.

关键词： efficient wave conversion vortex wave plane wave orbital angular momentum acoustic metasurface

Arbitrary acoustic orbital angular momentum detection using dual-layer metasurfaces

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 106-112页

作者： Zhanlei Hao Haojie chen Yuhang Yin Shan Zhu Yadong Xu cheng-Wei qiu Huanyang chen Department of Physics College of Physical Science and TechnologyXiamen UniversityXiamen 361005China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore Department of Mechanical and Electrical Engineering Xiamen UniversityXiamen 361005China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China School of Physical Science and Technology and Jiangsu Key Laboratory of Thin Films Soochow UniversitySuzhou 215006China

Orbital angular momentum(OAM),with its unique physical properties and vast application prospects,has attracted widespread attention in various ***,the development of valid and practical acoustic OAM detection methods continues to be a challenging *** this paper,we propose a novel construction method of dual-layer metasurfaces to achieve a doubleconversion process for the waveform reshaping and differentiated focusing of two-dimensional vortex sources with different ***,by utilizing a concise formula,a one-to-one correspondence is established between the OAM of incident vortex waves and different imaging *** fundamental principle of this special conversion relationship is rigorously constrained by the directional compensation of phase and the material parameters of dual-layer metasurfaces with different quadratic phase *** importantly,the highly consistent results between numerical demonstrations and acoustic experiments further confirm the feasibility and effectiveness of the proposed OAM detection *** work provides a new perspective on the precise manipulation for the phase of vortex fields,holding potential applications in super-resolution imaging and the design of acoustic OAM-based devices.

关键词： arbitrary acoustic OAM detection vortex waves dual-layer metasurfaces waveform reshaping differentiated focusing acoustic experiments

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用守恒元和解元法数值模拟二维溃坝洪水波

水利学报 2005年第10期36卷 1224-1229页

作者：张永祥陈景秋重庆大学工程力学系重庆400030

本文采用守恒元和解元方法(简称CE/SE法)来求解二维浅水方程,该方法从守恒积分型方程出发,严格遵守物理意义上的守恒律,通过设立守恒元和解元,从而提出一种新的数值模拟方法。用该方法计算得到的全溃的溃坝洪水波的数值解和理论解与文... 详细信息

本文采用守恒元和解元方法(简称CE/SE法)来求解二维浅水方程,该方法从守恒积分型方程出发,严格遵守物理意义上的守恒律,通过设立守恒元和解元,从而提出一种新的数值模拟方法。用该方法计算得到的全溃的溃坝洪水波的数值解和理论解与文献中的实验值符合的较好。在此基础上,进一步对二维局部溃坝洪水波的演进过程进行模拟,结果表明,CE/SE法精度较高,稳定性较好,其溃坝洪水波的间断具有很高的分辨率,能很好的模拟溃坝洪水波的运动过程。

关键词：溃坝洪水波守恒元和解元方法(CE/SE法) 数值模拟

An attention-based teacher-student model for multivariate short-term landslide displacement prediction incorporating weather forecast data

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Journal of Mountain Science 2024年第8期21卷 2739-2753页

作者： chen Jun HU Wang ZHANG Yu qiu Hongzhi WANG Renchao Sichuan Artificial Intelligence Research Institute Yibin 644000China School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China School of Architecture and Civil Engineering Chengdu UniversityChengdu 610106China

Predicting the displacement of landslide is of utmost practical importance as the landslide can pose serious threats to both human life and ***,traditional methods have the limitation of random selection in sliding window selection and seldom incorporate weather forecast data for displacement prediction,while a single structural model cannot handle input sequences of different lengths at the same *** order to solve these limitations,in this study,a new approach is proposed that utilizes weather forecast data and incorporates the maximum information coefficient(MIC),long short-term memory network(LSTM),and attention mechanism to establish a teacher-student coupling model with parallel structure for short-term landslide displacement *** MIC,a suitable input sequence length is selected for the LSTM *** investigate the influence of rainfall on landslides during different seasons,a parallel teacher-student coupling model is developed that is able to learn sequential information from various time series of different *** teacher model learns sequence information from rainfall intensity time series while incorporating reliable short-term weather forecast data from platforms such as China Meteorological Administration(CMA)and Reliable Prognosis(https://***)to improve the model’s expression capability,and the student model learns sequence information from other time *** attention module is then designed to integrate different sequence information to derive a context vector,representing seasonal temporal attention ***,the predicted displacement is obtained through a linear *** proposed method demonstrates superior prediction accuracies,surpassing those of the support vector machine(SVM),LSTM,recurrent neural network(RNN),temporal convolutional network(TCN),and LSTM-Attention *** achieves a mean absolute error(MAE)of 0.072 mm,root mean square error(RMSE)of 0.096 mm,and pearson correlation coefficients(PC

关键词： Landslide prediction MIC LSTM Attention mechanism Teacher Student model Prediction stability and interpretability

First-principles study on the electronic structure of Pb_(10−x)Cu_(x)(PO_(4))_(6)O(x=0,1)

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Journal of Materials Science & Technology 2024年第4期171卷 66-70页

作者： Junwen Lai Jiangxu Li Peitao Liu Yan Sun Xing-qiu chen Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

Recently,Lee et *** the experimental discovery of room-temperature ambient-pressure super-conductivity in a Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037).Remarkably,the claimed superconductivity can persist up to 400 K at ambient *** the experimental im-plication,the electronic structure of LK-99 has not yet been ***,we investigate the electronic structures of LK-99 and its parent compound using first-principles calculations,aiming to elucidate the doping effects of *** results reveal that the parent compound Pb_(10)(PO_(4))_(6)O is an insulator,while Cu doping induces an insulator-metal transition and thus volume *** band structures of LK-99 around the Fermi level are featured by a half-filled flat band and a fully-occupied flat *** two very flat bands arise from both the 2p orbitals of 1/4-occupied O atoms and the hybridization of the 3d orbitals of Cu with the 2p orbitals of its nearest-neighboring O ***,we observe four van Hove singularities on these two flat ***,we show that the flat band structures can be tuned by including electronic correlation effects or by doping different *** find that among the considered doping elements(Ni,Cu,Zn,Ag,and Au),both Ni and Zn doping result in the gap opening,whereas Au exhibits doping effects more similar to Cu than *** work establishes a foundation for fu-ture studies to investigate the role of unique electronic structures of LK-99 in its claimed superconducting properties.

关键词： First-principles calculations Density functional theory Electronic structur e Superconductivity Flat bands Strongly correlated electrons