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Metagenomic insights into the profile of antibiotic resistomes in sediments of aquaculture wastewater treatment system

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Journal of Environmental Sciences 2022年第3期34卷 345-355页

作者： Jianfei Chen Yuyin Yang Xinshu Jiang Yanchu Ke Tao He Shuguang Xie State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China State Key Joint Laboratory of Environment Simulation and Pollution Control(SKJLESPC) Beijing Key Laboratory for Emerging Organic Contaminants Control(BKLEOC)School of EnvironmentPOPs Research CenterTsinghua UniversityBeijing 100084China South China Institute of Environmental Sciences(SCIES) Ministry of Ecology and Environment(MEE)Guangzhou 510655China

To meet the rapidly growing global demand for aquaculture products,large amounts of antibiotics were used in aquaculture,which might accelerate the evolution of antibiotic-resistant bacteria(ARB)and the propagation of antibiotic genes(ARGs).In our research,we revealed the ARGs profiles,their co-occurrence with mobile genetic elements(MGEs),and potential hosts in sediments of a crab pond wastewater purification system based on metagenomic analysis.The residual antibiotic seems to increase the propagation of ARGs in the crab pond,but there was no clear relationship between a given antibiotic type and the corresponding resistance genes.The effect of aquaculture on sediment was not as profound as that of other anthropogentic activities,but increased the relative abundance of sulfon-amide resistance gene.A higher abundance of MGEs,especially plasmid,increased the po-tential ARGs dissemination risk in crab and purification ponds.Multidrug and sulfonamide resistance genes had greater potential to transfer because they were more frequently carried by MGEs.The horizontal gene transfer was likely to occur among a variety of microorgan-isms,and various ARGs hosts including Pseudomonas,Acinetobacter,Escherichia,and Klebsiella were identified.Bacterial community influenced the composition of ARG hosts,and Pro-teobacteria was the predominant hosts.Overall,our study provides novel insights into the environmental risk of ARGs in sediments of aquaculture wastewater treatment system.

关键词： Metagenomic sequencing Aquaculture Antibiotic resistome Antibiotic resistance genes(ARGs) Mobile genetic elements(MGEs) ARG hosts

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Phosphafluorenyl lithiums:direct synthesis from white phosphorus,structure and diversified synthons

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Science China Chemistry 2022年第2期65卷 322-327页

作者： Jingyuan Hu Zhengqi Chai Wei Liu Zhe Huang Junnian Wei Wen-Xiong Zhang Beijing National Laboratory for Molecular Sciences(BNLMS) State Key Laboratory of Rare Earth Materials Chemistry and Applications&Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of ChemistryPeking UniversityBeijing 100871China

While rich chemistry of phospholyl anions is discovered,phosphafluorenyl anions are only proposed as the critical intermediates for the synthesis of phosphafluorenes.In this article,we reported the direct synthesis of phosphafluorenyl lithiums from white phosphorus(P_(4))through direct P-C bond formation.The reaction between P4 and biphenyl dilithio reagents efficiently afforded phosphafluorenyl lithiums,which were further used to synthesize different kinds of organophosphorus compounds.The aggregation states of phosphafluorenyl lithiums were investigated for the first time.Mechanistic studies by DFT calculations revealed a cooperative nucleophilic attack of two C−Li bonds on P_(4)molecule.

关键词： white phosphorus organophosphorus compounds P–C bond formation P_(4)functionalization phosphafluorenyl lithium

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Triboelectric nanogenerators with a constant inherent capacitance design

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Nano Research 2023年第3期16卷 4077-4084页

作者： Lanyue Gan Fan Xia Panpan Zhang Xijun Jiang Yuxuan Liu Simiao Niu Youfan Hu Hunan Institute of Advanced Sensing and Information Technology Xiangtan UniversityXiangtan 411102China Key Laboratory for the Physics and Chemistry of Nanodevices Center for Carbon-Based ElectronicsAcademy for Advanced Interdisciplinary StudiesSchool of ElectronicsPeking UniversityBeijing 100871China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Biomedical Engineering Rutgers UniversityPiscatawayNJ 08854USA

Triboelectric nanogenerators(TENGs)utilize the phenomena of contact electrification and electrostatic induction to harvest mechanical energy from the environment.A good match between the motion frequency and the circuit characteristic frequency is critical for the effective power generation of a TENG.However,most TENGs have a time-dependent inherent capacitance(TICTENG),which hinders an optimal design for efficient energy conversion.Here,we propose a novel structure of a TENG with a constant inherent capacitance(CIC-TENG)and a mathematical model is established to provide analytical expressions of key output parameters of the device,which gives numerical simulation results that are in good agreement with the experimentally obtained results.Figures of merit and an optimization strategy are also given as guidelines for the optimization of material selection,geometry design,etc.Furthermore,a disk-formed CIC-TENG(DCIC-TENG)with polarity-switched triboelectric pairs is constructed to harvest unidirectional mechanical energy continuously,achieving an output power density of 55 mW/m^(2).The effects of the motion frequency,the number of electrodes and triboelectric pairs on the charge transfer efficiency of the DCICTENG are assessed and a preferred design strategy is given.Finally,the CIC-TENG demonstrates approximately two-fold advantages in power transfer efficiency over the TIC-TENG,and a DCIC-TENG-based self-powered anemometer was fabricated to measure wind speed in real time.

关键词： triboelectric nanogenerator inherent capacitance output power linearity

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Fourier neural operator with boundary conditions for efficient prediction of steady airfoil flows

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Applied Mathematics and Mechanics(English Edition) 2023年第11期44卷 2019-2038页

作者： Yuanjun DAI Yiran AN Zhi LI Jihua ZHANG Chao YU Department of Machanics and Engineering Science College of EngineeringPeking UniversityBeijing 100871China Beijing Institute of Mechanical and Electrical Engineering Beijing 100074China

An efficient data-driven approach for predicting steady airfoil flows is proposed based on the Fourier neural operator(FNO),which is a new framework of neural networks.Theoretical reasons and experimental results are provided to support the necessity and effectiveness of the improvements made to the FNO,which involve using an additional branch neural operator to approximate the contribution of boundary conditions to steady solutions.The proposed approach runs several orders of magnitude faster than the traditional numerical methods.The predictions for flows around airfoils and ellipses demonstrate the superior accuracy and impressive speed of this novel approach.Furthermore,the property of zero-shot super-resolution enables the proposed approach to overcome the limitations of predicting airfoil flows with Cartesian grids,thereby improving the accuracy in the near-wall region.There is no doubt that the unprecedented speed and accuracy in forecasting steady airfoil flows have massive benefits for airfoil design and optimization.

关键词： deep learning(DL) Fourier neural operator(FNO) steady airfoil flow

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Synthesis and structural analysis of titanium-μ-dinitrogen complex supported by di-anionic guanidinate ligands

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Science China Chemistry 2023年第3期66卷 755-759页

作者： Botao Wu Rui Feng Zhu-Bao Yin Haihan Yan Xueli Wang Gao-Xiang Wang Junnian Wei Zhenfeng Xi Key Laboratory of Bioorganic Chemistry and Molecular Engineering Ministry of Education and Beijing National Laboratory for Molecular ScienceCollege of ChemistryPekingUniversityBeijing100871China

The synthesis,characterization,and theoretical studies of titanium-μ-N_(2) complexes with di-anionic guanidinate ligands were reported as the first example of its kind.Thus,with(Me_(3)Si)_(2)N-guanidinate ligands,the mono-anionic guanidinate-supported titanium-μ-N2complex 1 was obtained.Then,reduction of 1 with potassium afforded the di-anionic guanidinate-supported titanium-μ-N_(2) complex 2 via cleavage of one N–Si bond of the(Me3Si)2N substituents in 1,changing the guanidinate ligands automatically from mono-anionic to di-anionic and remarkably lengthening the bond length of theμ-N_(2).Characteristic studies and DFT calculations were performed to reveal that the di-anionic guanidinate ligands stabilized the geometry of 2 and increased the charge density on the bridging dinitrogen.

关键词： dinitrogen complex di-anionic guanidinate ligand titanium

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A STOCHASTIC TRUST-REGION FRAMEWORK FOR POLICY OPTIMIZATION

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Journal of Computational Mathematics 2022年第6期40卷 1004-1030页

作者： Mingming Zhao Yongfeng Li Zaiwen Wen Beijing International Center for Mathematical Research Peking UniversityBeijing 100871China

In this paper,we study a few challenging theoretical and numerical issues on the well known trust region policy optimization for deep reinforcement learning.The goal is to find a policy that maximizes the total expected reward when the agent acts according to the policy.The trust region subproblem is constructed with a surrogate function coherent to the total expected reward and a general distance constraint around the latest policy.We solve the subproblem using a preconditioned stochastic gradient method with a line search scheme to ensure that each step promotes the model function and stays in the trust region.To overcome the bias caused by sampling to the function estimations under the random settings,we add the empirical standard deviation of the total expected reward to the predicted increase in a ratio in order to update the trust region radius and decide whether the trial point is accepted.Moreover,for a Gaussian policy which is commonly used for continuous action space,the maximization with respect to the mean and covariance is performed separately to control the entropy loss.Our theoretical analysis shows that the deterministic version of the proposed algorithm tends to generate a monotonic improvement of the total expected reward and the global convergence is guaranteed under moderate assumptions.Comparisons with the state-of-the–art methods demonstrate the effectiveness and robustness of our method over robotic controls and game playings from OpenAI Gym.

关键词： Deep reinforcement learning Stochastic trust region method Policy optimization Global convergence Entropy control

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针对电子极化子迁移的哈伯德U修正受限密度泛函理论方法:TiO_(2)实例研究

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Chinese Journal of Chemical Physics 2021年第5期34卷 541-551,I0002页

作者：王越超蒋鸿北京大学化学与分子工程学院北京分子科学研究中心北京100871

极化子的形成和迁移对过渡金属氧化物的物理和化学性质有重要影响.含哈伯德U修正的密度泛函理论和受限密度泛函理论方法经常被应用于小极化子迁移性质的理论研究.本文在投影缀加波框架中实现了哈伯德U修正的受限密度泛函理论(cDFT+U),... 详细信息

极化子的形成和迁移对过渡金属氧化物的物理和化学性质有重要影响.含哈伯德U修正的密度泛函理论和受限密度泛函理论方法经常被应用于小极化子迁移性质的理论研究.本文在投影缀加波框架中实现了哈伯德U修正的受限密度泛函理论(cDFT+U),并将其应用于体相TiO_(2)中的极化子迁移性质的计算.确认了哈伯德U的取值对极化子性质的理论预测有重要影响.采用基于cDFT计算所获得的哈伯德U值,可对TiO_(2)金红石和锐钛矿相中的极化子性质获得与实验符合很好的描述.本文表明,使用与理论上一致的方式计算获得的哈伯德U值,cDFT+U有望成为一种有效的不需经验输入而计算过渡金属氧化物极化子性质的第一性原理方法.

关键词：小极化子受限密度泛函理论哈伯德U修正二氧化钛

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Design method and machine learning application of acoustic holographic computational metamaterials

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Science China(Technological Sciences) 2022年第1期65卷 238-243页

作者： LV ZengYao LI JianQing HOU ZeWei DING YuanShuai XU WangDong PEI YongMao Department of Engineering Mechanics/Center for Flexible Electronics Technology Applied Mechanics LaboratoryTsinghua UniversityBeijing 100084China State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceCollege of EngineeringPeking UniversityBeijing 100871China

Acoustic holographic method has been used in imaging,particle manipulation,material preparation and other fields.In acoustics,it is important to design the implementation of any acoustic wave formation surface[1-5].Tr... 详细信息

关键词： holographic method acoustics

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Calculation of Feynman loop integration and phase-space integration via auxiliary mass flow

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Chinese Physics C 2021年第1期45卷 162-174页

作者：刘霄马滟青陶伟张鹏 School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China Center for high Energy Physics Peking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China

We extend the auxiliary-mass-flow(AMF) method originally developed for Feynman loop integration to calculate integrals which also involve phase-space integration.The flow of the auxiliary mass from the boundary(∞) to the physical point(0+) is obtained by numerically solving differential equations with respective to the auxiliary mass.For problems with two or more kinematical invariants,the AMF method can be combined with the traditional differential-equation method,providing systematic boundary conditions and a highly nontrivial self-consistency check.The method is described in detail using a pedagogical example of e+e-→γ*→tt+X at NNLO.We show that the AMF method can systematically and efficiently calculate integrals to high precision.

关键词： phase-space integration perturbation theory multi-loop

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Temporal Unfolding of Racial Ingroup Bias in Neural Responses to Perceived Dynamic Pain in Others

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Neuroscience Bulletin 2024年第2期40卷 157-170页

作者： Chenyu Pang Yuqing Zhou Shihui Han School of Psychological and Cognitive Sciences PKU-IDG/McGovern Institute for Brain ResearchBeijing Key Laboratory of Behavior and Mental HealthPeking UniversityBeijing 100081China CAS Key Laboratory of Behavioral Science Institute of PsychologyChinese Academy of SciencesBeijing 100101China Department of Psychology University of Chinese Academy of SciencesBeijing 100049China

In this study,we investigated how empathic neural responses unfold over time in different empathy networks when viewing same-race and other-race individuals in dynamic painful conditions.We recorded magnetoencephalography signals from Chinese adults when viewing video clips showing a dynamic painful(or non-painful)stimulation to Asian and White models’faces to trigger painful(or neutral)expressions.We found that perceived dynamic pain in Asian models modulated neural activities in the visual cortex at 100 ms–200 ms,in the orbitofrontal and subgenual anterior cingulate cortices at 150 ms–200 ms,in the anterior cingulate cortex around 250 ms–350 ms,and in the temporoparietal junction and middle temporal gyrus around 600 ms after video onset.Perceived dynamic pain in White models modulated activities in the visual,anterior cingulate,and primary sensory cortices after 500 ms.Our findings unraveled earlier dynamic activities in multiple neural circuits in response to same-race(vs other-race)individuals in dynamic painful situations.

关键词： Empathy Race Magnetoencephalography Dynamic pain Cingulate cortex

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