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Journal of Iron and Steel Research International 2024年第4期31卷 894-908页

作者： Yan-li Xin Zhi-ying Gao bo Tian Qing-dong Zhang School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China

In the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product *** instability behavior is closely related to interfacial friction-lubrication con-dition which is generally characterized by the friction ***,with higher and higher speed requirements,the commonly used model of friction coefficient is no longer applicable and accurate.A novel approach is suggested to calculate the speed-dependent friction coefficient,in which the viscosity-pressure-temperature effects of the lubricant,surface roughness states of work rolls and rolled piece are comprehensively involved and the mixed flm lubrication theory is ***,the influences of friction coefficient on the instability of slip and chatter are investigated for a five-stand cold tandem rolling *** one side,the critical friction coefficient for each stand is determined by calculating the corresponding slip factor;on the other hand,the friction coefficient varying with rolling speed is combined with the model of theoretical critical rolling speed presented under constant friction coefficient,so that the speed threshold is ***,the stable and unstable regions corresponding to the rear three stands are individually discussed,and the technical strategies are proposed to suppress both slip and chatter frequently occurring in the actual rolling process.

关键词： Cold tandem rolling:Oil film thickness Speed-dependent friction coefficient-Slip:Chatter

Dietary cooking oils and cardiometabolic measurements in an elderly Chinese population

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Journal of Geriatric Cardiology 2024年第6期21卷 642-650页

作者： Xin-Yu WANG Chao-ying MIAO Xiao-Fei YE Wen-Yuan-Yue WANG jia-bo ZHU Yi ZHOU Yan LI Ji-Guang WANG School of Public Health Shanghai Jiao Tong University School of MedicineShanghaiChina Department of Cardiovascular Medicine Centre for Epidemiological Studies and Clinical TrialsThe Shanghai Institute of HypertensionRuijin HospitalShanghai Jiao Tong University School of MedicineShanghaiChina

OBJECTIVE To investigate three features of dietary cooking oil intake,namely,the consumption,cooking style,and composition of fatty acids in relation to several cardiometabolic measurements in an elderly Chinese *** The elderly(≥65 years)participants for this study were recruited from two community health centers in the urban area of Shanghai.A questionnaire was administered to collect information on dietary oil consumption(low,medium and high)and cooking styles(fry or stir-fry ***)and the composition of fatty acids(poly-unsaturated ***-unsaturated).The cardiometabolic measurements included anthropometry,blood pressure,fasting plasma glucose and serum *** The 1186 study participants had a mean age of 70.9±5.4 *** mean dietary oil consumption was 35.0 g/d,being low(bove and additional adjustment for dietary oil consumption,the fry or stir-fry cooking style was significantly(P≤0.048)and positively associated with body mass index,but inversely with systolic and diastolic blood pressure and serum low-density lipoprotein cholesterol,and the dietary intake of oils rich in mono-unsaturated fat acids was significantly(P≤0.02)and positively associated with diastolic blood pressure,serum triglycerides,total cholesterol and low-density lipoprotein cholesterol,and the prevalence of hypertriglyceridemia and *** This study showed that both the consumption and composition of fatty acids of the dietary oils mattered with regard to sev

关键词： cooking elderly unsaturated

Spatial and temporal variation of water clarity in typical reservoirs in the Beijing-Tianjin-Hebei region observed by GF 1-WFV satellite data

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Journal of Oceanology and Limnology 2024年第4期42卷 1048-1060页

作者： Chang CAO Junsheng LI Xiaodong jia Shenglei WANG bo WAN Liaoning Earthquake Agency Shenyang 11000China Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China International Research Center of Big Data for Sustainable Development Goals Beijing 100094China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China

Rapidly monitoring regional water quality and the changing trend is of great practical and scientific significance,especially for the Beijing-Tianjin-Hebei(BTH)region of China where water resources are relatively scarce and inland water bodies are generally *** remote sensing data of the GF 1 satellite launched in 2013 have characteristics of high spatial and temporal resolution,which can be used for the dynamic monitoring of the water environment in small lakes and ***,the water quality remote sensing monitoring model based on the GF 1 satellite data for lakes and reservoirs in BTH is still lacking because of the considerable differences in the optical characteristics of the lakes and *** this paper,the typical reservoirs in BTH-Guanting Reservoir,Yuqiao Reservoir,Panjiakou Reservoir,and Daheiting Reservoir are taken as the study *** the atmospheric correction of GF 1-WFV,the relative radiation normalized atmospheric correction was adopted after comparing it with other methods,such as 6 S and *** the water clarity retrieval,a water color hue angle based model was proposed and outperformed other available published models,with the R 2 of 0.74 and MRE of 31.7%.The clarity products of the four typical reservoirs in the BTH region in 2013-2019 were produced using the GF 1-WFV *** on the products,temporal and spatial changes in clarity were analyzed,and the main influencing factors for each water body were *** was found that the clarity of Guanting,Daheiting,and Panjiakou reservoirs showed an upward trend during this period,while that of Yuqiao Reservoir showed a downward *** the influencing factors,the water level of the water bodies can be an important factor related to the water clarity changes in this region.

关键词： GF 1 satellite atmospheric correction clarity Beijing-Tianjin-Hebei spatial and temporal change analysis

Tuning Synaptic Connections Instead of Weights by Genetic Algorithm in Spiking Policy Network

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Machine Intelligence Research 2024年第5期21卷 906-918页

作者： Duzhen Zhang Tielin Zhang Shuncheng jia Qingyu Wang bo Xu School of Artificial Intelligence University of Chinese Academy of SciencesBeijing100049China Institute of Automation Chinese Academy of Sciences(CAS)Beijing100190China Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of Sciences(CAS)Shanghai200031China

Learning from interaction is the primary way that biological agents acquire knowledge about their environment and *** deep reinforcement learning(DRL)explores a computational approach to learning from interaction and has made significant progress in solving various ***,despite its power,DRL still falls short of biological agents in terms of energy *** the underlying mechanisms are not fully understood,we believe that the integration of spiking communication between neurons and biologically-plausible synaptic plasticity plays a prominent role in achieving greater energy *** this biological intuition,we optimized a spiking policy network(SPN)using a genetic algorithm as an energy-efficient alternative to *** SPN mimics the sensorimotor neuron pathway of insects and communicates through event-based *** by biological research showing that the brain forms memories by creating new synaptic connections and rewiring these connections based on new experiences,we tuned the synaptic connections instead of weights in the SPN to solve given *** results on several robotic control tasks demonstrate that our method can achieve the same level of performance as mainstream DRL methods while exhibiting significantly higher energy efficiency.

关键词： Spiking neural networks genetic evolution bio-inspired learning agent&cognitive architectures robotic control

Enhanced photocatalytic performance by regulating the Ce^(3+)/Ce^(4+)ratio in cerium dioxide

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 75-87页

作者： Zhi Li Dongsheng jia Wei Zhang ying Li Mitang Wang Dongliang Zhang School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai200093China

Cerium dioxide(CeO_(2))photocatalysts are used in treating environmental pollution and addressing the energy crisis due to their excellent oxygen storage capacities and abundant oxygen *** this paper,CeO_(2)precursors were synthesized with different water-alcohol ratios via a solvothermal method,and CeO_(2)photocatalysts with different Ce^(3+)/Ce^(4+)ratios were obtained by changing the precursor calcination atmospheres(air,Ar)as well as the calcination *** effects of CeO_(2)with different Ce^(3+)/Ce^(4+)ratios in photocatalytic degradations of methylene blue under visible light were investigated.X-ray photoelectron spectroscopy results showed that the surfaces of the samples calcined under Ar had higher Ce^(3+)/Ce^(4+)ratios and oxygen vacancy concentrations,which reduced the band gaps of the catalysts and improved their utilization of visible *** addition,the many Ce^(3+)/Ce^(4+)redox centers and oxygen vacancies on the sample surfaces improved the separation and transfer efficiencies of the photogenerated *** sample C2-Ar calcined under Ar showed a high adsorption capacity and excellent photocatalytic activity by removing 96%of the methylene blue within 120 min,which was more than twice the degradation rate of the sample(C2-air)prepared via calcination under *** experiments showed that photogenerated holes played a key role in the photocatalytic *** addition,a synergistic photocatalytic mechanism for the Ce^(3+)/Ce^(4+)redox centers and oxygen vacancies was elucidated in detail,and the sensitization of cerium dioxide by dyes aided the degradation of methylene blue.

关键词： CeO_(2) oxygen vacancies Ce^(3+)/Ce^(4+)ratios photocatalytic dye-sensitization

Hydrochemical Characteristics and Evolution of Underground Brine in Lop Nur,Northwestern China

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Acta Geologica Sinica(English Edition) 2024年第3期98卷 786-800页

作者： bo ying LIU Chenglin jiaO Pengcheng LU Fenglin ZHANG Hua MNR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China

Lop Nur is located at the eastmost end of the Tarim Basin in Xinjiang,Northwestern *** study reviews the hydrochemical characteristics and evolution of underground brine in Lop Nur,based on analytical data from 429 water samples(mainly brine).It is found that in the NE-SW direction,from the periphery to the Luobei sub-depression,while the hydrochemical type varies from the sodium sulfate subtype(S)to the magnesium sulfate subtype(M),the corresponding brine in the phase diagram transfers from the thenardite phase(Then)area,through the bloedite phase(Blo),epsomite phase(Eps),picromerite phase(Picro),finally reaching the sylvite phase(Syl)*** for the degree of evolution,the sequence is the peripheryying glauberite brineying clastic brine *** is concluded that the oxygen and hydrogen isotopic compositions of the brine have evidently been affected through the effects of evaporation and altitude,as well as the changes in local water circulation in recent *** and chloride isotopic compositions show that the glauberite brine is formed under more arid conditions than the clastic *** strontium isotopic composition indicates that the Lop Nur brine primarily originates from surface water;however,deep recharge may also be involved in the evolution of the brine,according to previous noble gas *** is confirmed that the brine in Lop Nur has become enriched with potassium prior to halite precipitation over the full course of the salt lake's *** on chemical compositions of brine from drillhole LDK01 and previous lithological studies,the evolution of the salt lake can be divided into three stages and it is inferred that the brine in Lop Nur may have undergone at least two significant concentration-dilution periods.

关键词： brine evolution isotope enrichment potassium Lop Nur

A Weakly-Supervised Crowd Density Estimation Method Based on Two-Stage Linear Feature Calibration

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 965-981页

作者： Yong-Chao Li Rui-Sheng jia ying-Xiang Hu Hong-Mei Sun the College of Computer Science and Engineering Shandong University of Science and TechnologyQingdao 266590 the Faculty of Information Science and Engineering Ocean University of ChinaQingdao 266000China the College of Computer Science and Engineering Shandong University of Science and TechnologyQingdao 266590China the College of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210000China

In a crowd density estimation dataset,the annotation of crowd locations is an extremely laborious task,and they are not taken into the evaluation *** this paper,we aim to reduce the annotation cost of crowd datasets,and propose a crowd density estimation method based on weakly-supervised learning,in the absence of crowd position supervision information,which directly reduces the number of crowds by using the number of pedestrians in the image as the supervised *** this purpose,we design a new training method,which exploits the correlation between global and local image features by incremental learning to train the ***,we design a parent-child network(PC-Net)focusing on the global and local image respectively,and propose a linear feature calibration structure to train the PC-Net simultaneously,and the child network learns feature transfer factors and feature bias weights,and uses the transfer factors and bias weights to linearly feature calibrate the features extracted from the Parent network,to improve the convergence of the network by using local features hidden in the crowd *** addition,we use the pyramid vision transformer as the backbone of the PC-Net to extract crowd features at different levels,and design a global-local feature loss function(L2).We combine it with a crowd counting loss(LC)to enhance the sensitivity of the network to crowd features during the training process,which effectively improves the accuracy of crowd density *** experimental results show that the PC-Net significantly reduces the gap between fullysupervised and weakly-supervised crowd density estimation,and outperforms the comparison methods on five datasets of Shanghai Tech Part A,ShanghaiTech Part B,UCF_CC_50,UCF_QNRF and JHU-CROWD++.

关键词： Crowd density estimation linear feature calibration vision transformer weakly-supervision learning

Understanding adversarial attacks on observations in deep reinforcement learning

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Science China(Information Sciences) 2024年第5期67卷 69-83页

作者： You QIAOBEN Chengyang ying Xinning ZHOU Hang SU Jun ZHU bo ZHANG Department of Computer Science and Technology Beijing National Research Center for Information Science and Technology Tsinghua-Bosch Joint Center for Machine Learning Institute for Artificial Intelligence Tsinghua University Peng Cheng Laboratory

Deep reinforcement learning models are vulnerable to adversarial attacks that can decrease the cumulative expected reward of a victim by manipulating its observations. Despite the efficiency of previous optimization-based methods for generating adversarial noise in supervised learning, such methods might not achieve the lowest cumulative reward since they do not generally explore the environmental ***, a framework is provided to better understand the existing methods by reformulating the problem of adversarial attacks on reinforcement learning in the function space. The reformulation approach adopted herein generates an optimal adversary in the function space of targeted attacks, repelling them via a generic two-stage framework. In the first stage, a deceptive policy is trained by hacking the environment and discovering a set of trajectories routing to the lowest reward or the worst-case performance. Next, the adversary misleads the victim to imitate the deceptive policy by perturbing the observations. Compared to existing approaches, it is theoretically shown that our adversary is strong under an appropriate noise level. Extensive experiments demonstrate the superiority of the proposed method in terms of efficiency and effectiveness, achieving state-of-the-art performance in both Atari and MuJoCo environments.

关键词： deep learning reinforcement learning adversarial robustness adversarial attack

New strategies for asymmetric photocatalysis: asymmetric organocatalytic/photoredox relay catalysis for efficient synthesis of polycyclic compounds containing vicinal amino alcohols

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Science China Chemistry 2024年第3期67卷 945-952页

作者： jia-Lu Zhang Wen-bo He Xiu-Qin Hu Peng-Fei Xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China State Key Laboratory of Veterinary Etiological Biology College of Veterinary MedicineLanzhou UniversityLanzhou Veterinary Research InstituteChinese Academy of Agricultural SciencesLanzhou 730000China MOE Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China

An asymmetric catalytic strategy in photocatalysis utilizing a chirality-induced approach through an organocatalytic/photoredox relay catalysis strategy is successfully achieved for the rapid construction of polycyclic compounds containing vicinal amino alcohols in a one-pot protocol. This methodology facilitates the efficient synthesis of diverse substituted polycyclic tetrahydroquinoline and benzofuran-derived vicinal amino alcohols, each containing five consecutive chiral centers, with high yields,excellent diastereoselectivities and enantioselectivities(up to 95% yield, >20:1 dr and 98% ee), under mild reaction conditions driven by sequential bifunctional squaramide organocatalyst-catalyzed [4+2] annulation and photocatalyst-catalyzed ketyl radical addition cyclization reaction process. Furthermore, investigations into the stereoselectivity mechanism and high-resolution mass spectrometry(HRMS) experiments on free radical trapping have provided evidence for elucidating the detailed mechanism of chirality-induced processes and chiral intermediate conversions in this procedure.

关键词： enantioselective photocatalysis asymmetric organocatalytic/photocatalysis relay catalysis five consecutive chiral centers chirality-induced strategy chirality vicinal amino alcohols

Single-cell RNA sequencing to understand host-virus interactions

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Virologica Sinica 2024年第1期39卷 1-8页

作者： jia-Tong Chang Li-bo Liu Pei-Gang Wang Jing An Department of Microbiology School of Basic Medical SciencesCapital Medical UniversityBeijing 100069China

Single-cell RNA sequencing(scRNA-seq)has allowed for the profiling of host and virus transcripts and host-virus interactions at single-cell *** review summarizes the existing scRNA-seq technologies together with their strengths and *** applications of scRNA-seq in various virological studies are discussed in depth,which broaden the understanding of the immune atlas,host-virus interactions,and immune ***-seq can be widely used for virology in the near future to better understand the pathogenic mechanisms and discover more effective therapeutic strategies.

关键词： Single-cell RNA sequencing(scRNA-seq) Host-virus interaction COVID-19 Flavivirus