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Combined effect of WS_(2) and ti_(3)C_(2)t_(x) MXene favors oil-based ultra-low friction on rough steel-steel interface at elevated temperatures

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Science China(technological Sciences) 2024年第7期67卷 1991-2002页

作者： liu YangQin CHEN Lei WANG Yang QIAN LinMao tribology Research Institute State Key Laboratory of Rail Transit Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Key Laboratory of Advanced technologies of Materials(Ministry of Education) Research Institute of Frontier ScienceSouthwest Jiaotong UniversityChengdu 610031China

the lubrication performance of liquids is severely restricted and is degraded in high-temperature environments. Stable and reliable lubrication in high temperature environments has been a long-standing goal in various industrial fields. In this study,WS_(2)and ti_(3)C_(2)t_(x)MXene nanoflakes were used as oil-based lubricant additives to generate ultra-low friction and even superlubricity(friction coefficient of ~0.007) at elevated temperatures(400℃), which has hitherto not been achieved by both individual pristine materials, WS_(2)and ti_(3)C_(2)t_(x)MXene. Viscosity and thermogravimetric characterization revealed improvements in the high-temperature rheological properties and thermal stability of the lubricating base oil, indicating improved loadbearing and continuous lubrication capabilities at elevated temperatures. X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy demonstrated that the formation of an iron/titanium/tungsten-rich oxide lubricious thin film at the sliding interface reduced the interfacial shear stress, which was responsible for the observed friction and wear reductions at high contact pressures(> 1.1 GPa). Although the titanium/tungsten oxide film was gradually removed after prolonged sliding, a sufficiently thick iron oxide film maintained a low friction coefficient for at least 2 h. the improved surface quality facilitates the achievement of ultra-low friction and reduced wear. the proposed lubrication methodology has a broad utilization potential as a wear-reduction strategy across various industrial fields at elevated temperatures.

关键词： ultra-low friction high-temperature wear reduction lubricating additive tungsten disulfide MXene

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Fast and Adaptive Multi-Agent Planning under Collaborative temporal Logic tasks via Poset Products

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Research 2024年第2期2024卷 81-94页

作者： Zesen liu Meng Guo Weimin Bao Zhongkui Li Deparment of Mechanics and Engineering Science College of EngineeringPeking UniversityBejing 0081 China Science and technology Commission of China Aerospace Science and technology Corporation Beijing 100048China

Efficient coordination and planning is essential for large-scale multi-agent systems that collaborate in a shared dynamic environment. Heuristic search methods or learning-based approaches often lack the guarantee on correctness and performance. Moreover, when the collaborative tasks contain both spatial and temporal requirements, e.g., as linear temporal logic (LtL) formulas, formal methods provide a verifiable framework for task planning. However, since the planning complexity grows exponentially with the number of agents and the length of the task formula, existing studies are mostly limited to small artificial cases. to address this issue, a new planning paradigm is proposed in this work for system-wide temporal task formulas that are released online and continually. It avoids two common bottlenecks in the traditional methods, i.e., (a) the direct translation of the complete task formula to the associated B點hi automaton and (b) the synchronized product between the B點hi automaton and the transition models of all agents. Instead, an adaptive planning algorithm is proposed, which computes the product of relaxed partially ordered sets (R-posets) on-the-fly and assigns these subtasks to the agents subject to the ordering constraints. It is shown that the first valid plan can be derived with a polynomial time and memory complexity with respect to the system size and the formula length. Our method can take into account task formulas with a length of more than 400 and a fleet with more than 400 agents, while most existing methods fail at the formula length of 25 within a reasonable duration. the proposed method is validated on large fleets of service robots in both simulation and hardware experiments.

关键词： hardware service system

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Effects of orientation on the fatigue crack growth behaviors of the ZK60 magnesium alloy in air and PBS

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Journal of Magnesium and Alloys 2024年第1期12卷 281-294页

作者： Jiaqi Hu Zheng liu Zuoliang Ning Hong Gao School of Chemical Engineering and technology Tianjin UniversityTianjin 300072China tianjin Key Laboratory of Chemical Process Safety and Equipment technology Tianjin 300072China

Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium *** investigate the influences of specimen orientation,the corrosion tests and(corrosion)fatigue crack growth tests were *** rolled and transverse surfaces of the materials show distinct corrosion rate differences in the stable corrosion stage,but the truth is the opposite for the initial stage of *** air,specimen orientations have a significant influence on the plastic deformation mechanisms near the crack tip,which results in different fatigue fracture surfaces and cracking *** with R-t specimens,N-t specimens show a slower fatigue crack growth(FCG)rate in air,which can be attributed to crack closure effects and deformation twinning near the crack *** corrosion environment will not significantly change the main plastic deformation mechanisms for the same type of ***,the FCG rate in phosphate buffer saline(PBS)is one order of magnitude higher than that in air,which is caused by the combined effects of hydrogen-induced cracking and anodic *** to the similar corrosion rates at crack tips,the specimens with different orientations display close FCG rates in PBS.

关键词： Magnesium alloy Orientation Corrosion Fatigue crack growth

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Numerical Study on Forming Process of the PEt/PA6 Component Melt in Micro Hole in Composite Spinning

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Journal of Donghua University(English Edition) 2013年第6期30卷 510-513页

作者： Wang L. Ji J.-Y. liu t.-t. Gan X.-H. Engineering Research Center of Advanced textile Machinery Ministry of Education Donghua University Shanghai 201620 China College of Mechanical Engineering Donghua University Shanghai 201620 China

the forming mechanism of the multi-component polymer melt is always the difficult problem in the study on the composite fiber,due to the difference of the material *** study simulated the flow of PEt/PA6 composite melt on the influence law for the velocity distribution and the micro hole's structure on the influence law for extrusion swelling based on the theory of the rheology and the spinning process and the structure of the spinning components by *** addition by comparison with the previous experiments about extrusion swelling,the results show that the value of the swell ratio decreases rapidly at low values of length/diameter and then levels off as length/diameter is increased further,whereas increases with the die exit angle *** velocity distribution of the composite melt and the micro hole's structure have a significant influence on the extrusion swelling,which has very good guidance function for studying the forming mechanism of the composite melt and preparation of the high performance fiber.

关键词： PEt PA6 聚合物熔体纺丝组件数值研究复合纺丝微孔 POLYFLOW 挤出膨胀

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Enhancing XRF sensor-based sorting of porphyritic copper ore using particle swarm optimization-support vector machine(PSO-SVM)algorithm

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International Journal of Mining Science and technology 2024年第4期34卷 545-556页

作者： Zhengyu liu Jue Kou Zengxin Yan Peilong Wang Chang liu Chunbao Sun Anlin Shao Bern Klein School of Civil and Resources Engineering University of Science and TechnologyBeijing 100083China Institute of Minerals Research University of Science and TechnologyBeijing 100083China State Key Laboratory of Mineral Processing Beijing 102628China Ansteel Group Mining Co.Ltd. Anshan 114000China Norman B.Keevil Institute of Mining Engineering University of British ColumbiaVancouverBC V6T 1Z4Canada

X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hindering widespread technology *** classification models are crucial to determine if actual grade exceeds the sorting threshold using localized XRF *** studies mainly used linear regression(LR)algorithms including simple linear regression(SLR),multivariable linear regression(MLR),and multivariable linear regression with interaction(MLRI)but often fell short attaining satisfactory *** study employed the particle swarm optimization support vector machine(PSO-SVM)algorithm for sorting porphyritic copper ore ***-scale results showed PSO-SVM out-performed LR and raw data(RD)models and the significant interaction effects among input features was *** poor input data quality,PSO-SVM demonstrated exceptional ***-scale sorting achieved 93.0%accuracy,0.24%grade increase,84.94%recovery rate,57.02%discard rate,and a remarkable 39.62 yuan/t net smelter return(NSR)increase compared to no *** improvements were achieved by the PSO-SVM model with optimized input combinations and highest data quality(t=10,t is XRF testing times).the unsuitability of LR methods for XRF sensor-based sorting of investigated sample is *** element selection and mineral association analysis elucidate element importance and influence mechanisms.

关键词： XRF sensor-based sorting PSO-SVM algorithm Copper ore pebble Receiver operating curve(ROC) Net smelter return(NSR)

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Detection of a reassortant swine H1N2 influenza A virus from pigs in Hong Kong

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Virologica Sinica 2024年第2期39卷 343-346页

作者： Guoqian Gu Congnuan liu Song Hao Lee Lewis Sze Chun Choi Michael t.Wilson Dirk U.Pfeiffer Yun Young Go Department of Infectious Diseases and Public Health Jockey Club College of Veterinary Medicine and Life SciencesCity University of Hong KongHong Kong SARChina Center for Applied One Health Research and Policy Advice Jockey Club College of Veterinary Medicine and Life SciencesCity University of Hong KongHong Kong SARChina College of Veterinary Medicine Konkuk UniversitySeoul143-701Republic of Korea

Dear Editor,Influenza A viruses(IAVs)are responsible for significant respiratory illnesses in humans and a broad range of animal *** outbreaks and the rapid spread of genetically and antigenically distinct IAVs represent a considerable challenge for swine *** are susceptible to avian and human IAV infections and are considered“mixing vessels”where human,avian,and swine IAVs can recombine and generate novel reassortant influenza viruses with pandemic potential(Vincent et al.,2014).

关键词： swine influenza mixing

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Nickel-Catalyzed Regioselective Hydrosilylation of Conjugated Dienes

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Chinese Journal of Chemistry 2024年第1期42卷 13-19,I0004页

作者： Xiaoyu Wu Wei liu Liqun Yang Yue Wang tianwen liu Yao Yuan Yan Lu Zhaoguo Zhang Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs School of Chemistry and Chemical EngineeringShanghai JiaoTong University800 Dongchuan RoadShanghai 200240China Joseph Black Building The University of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK

With the increasing demand for homoallylic silanes and allylic silanes,the highly efficient and regioselective hydrosilylations of conjugated dienes are urgently ***,we developed a Ni-catalyzed regiodivergent hydrosilylation of aromatic conjugated dienes by adjusting the temperature and *** low temperature(-30℃),an eternal-ligand-free system(Ni/t-BuOk)can efficiently facilitate the 3,4-anti-Markovnikov hydrosilylation to provide homoallylic silanes via electrophilic activation process;under room temperature(25℃),a ligand-controlled system(Ni/t-BuOk/PPh3)can eventuate the 3,4-Markovnikov hydrosilylation to produce allylic silanes via Chalk-Harrod *** systems are compatible with various conjugated dienes and primary silanes in excellent yields andregioselectivities.

关键词： Nickel-catalyzed Regioselective hydrosilylation Conjugated dienes Electrophilic activation Homoallylic silanes

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An efficient method for constructing a random insertional mutant library for forward genetics in Nannochloropsis oceanica

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Journal of Oceanology and Limnology 2024年第1期42卷 216-225页

作者： Zhongyi ZHANG Hang liu Xiaohui PAN Yanan ZONG Leili FENG Lixian liu Li GUO Guanpin YANG College of Marine Life Sciences Ocean University of ChinaQingdao 266003China Institutes of Evolution and Marine Biodiversity Ocean University of ChinaQingdao 266003China Key Laboratory of Marine Genetics and Breeding of Ministry of Education Ocean University of ChinaQingdao 266003China

Insertional mutation,phenotypic evaluation,and mutated gene cloning are widely used to clone genes from *** genes can be integrated into the genome during non-homologous end joining(NHEJ)of the double-strand breaks of DNA,causing insertional *** random insertional mutant library constructed using this method has become a method of forward genetics for gene ***,the establishment of a random insertional mutant library requires a high transformation efficiency of exogenous *** microalgal species show a low transformation efficiency,making constructing random insertional mutant libraries *** this study,we established a highly efficient transformation method for constructing a random insertional mutant library of Nannochloropsis oceanica,and tentatively tried to isolate its genes to prove the feasibility of the method.A gene that may control the growth rate and cell size was *** method will facilitate the genetic studies of ***,which should also be a reference for other microalgal species.

关键词： Nannochloropsis oceanica genetic transformation random insertional mutant library zeocin pretreatment forward genetics

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Geochronology,Geochemistry,and Sr-Nd-Hf Isotopes of the Diorite Porphyrites from the Weining Beishan Area,Ningxia Hui Autonomous Region:Constraints on their Source and tectonic Implications

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Journal of Earth Science 2024年第2期35卷 462-475页

作者： Anlu liu Lianfu Hai Jinke liu Xiaojun Zhang Haifeng Li Fengshun Zhao Guoliang Zhao Jinhe Bai Yifu Museum China University of GeosciencesWuhan430074China School of Earth Resources China University of GeosciencesWuhan430074China Mineral Geological Survey Institute of Ningxia Hui Autonomous Region Yinchuan750021China National Demonstration Center for Experimental Mineral Exploration Education China University of GeosciencesWuhan430074China Coal Geological Survey Institute of Ningxia Hui Autonomous Region Yinchuan750021China Zhuhai Engineering Investigation Institute of Guangdong Province Zhuhai519000China

the Weining Beishan area of Ningxia Hui Autonomous Region is located at on the western edge of the Helanshan tectonic belt,which is a tectonic joint among Alxa Block,Ordos Block,and North Qilian orogenic ***,the tectonic evolution of this area remains unclear due to the lack of magmatic *** paper conducted researches on geochronology,geochemistry,and Sr-Nd-Hf isotopes of the diorite porphyrites exposed in the Weining Beishan *** zircon U-Pb dating yields two ages of 145.0±1.1 and 146.2±1.5 Ma,and the whole-rock geochemical data indicate that the diorite porphyrites are metaluminous to weakly peraluminous and high-K calc-alkaline *** characteristics of highly initial^(87)Sr/^(86)Sr ratios(0.70816 to 0.71047),negativeε_(Nd)(t)(−8.9 to−8.4),and negativeε_(Hf)(t)(−13.8 to−21.2)indicate that the diorite porphyrites originated from partial melting of the middle-lower ancient crust related to the North China *** with the regional geology,we suggested that partial melting was triggered by a tectonic activity of deep faults cutting through the crust under the regional stress transformation from compressing to extension during the Late Jurassic–Early Cretaceous,which is probably related to the westward subduction of the Paleo-Pacific Plate.

关键词： zircon U-Pb dating Sr-Nd-Hf isotopes magma source diorite porphyrite Weining Beishan area Ningxia Hui Autonomous Region geochronology geochemistry

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Proteomics analysis of coronary atherosclerotic heart disease with different traditional Chinese Medicine syndrome types before and after percutaneous coronary intervention

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Journal of traditional Chinese Medicine 2024年第3期44卷 554-563页

作者： WANG Zhibo LI Ying WANG Daoping MA Bo MIAO Lan REN Junguo liu Jinghua liu Jianxun Beijing Key Laboratory of Pharmacology of Chinese Materia Region Institute of Basic Medical SciencesXiyuan HospitalChina Academy of Chinese Medical SciencesNational Clinical Research Center of Cardiovascular Disease of Traditional Chinese Medicine the National Key Facility for Crop Gene Resources and Genetic Improvement Institute of Crop ScienceChinese Academy of Agricultural Science Department of Cardiology Beijing Anzhen HospitalCapital Medical University

OBJECtIVE: to investigate the underlying protein molecular mechanisms of "Qi stagnation and blood stasis syndrome"(QS) and "Qi deficiency and blood stasis syndrome"(QD), as two subtypes of coronary artery disease(CAD) in traditional Chinese Medicine(tCM),following percutaneous coronary intervention(PCI).MEtHODS: In this study, a total of 227 CAD patients with QS and 211 CAD patients with QD were enrolled; all participants underwent PCI. Label-free quantification proteomics were employed to analyze the changes in serum in two subtypes of CAD patients before and 6 months after PCI, aiming to elucidate the intervention mechanism of PCI in treating CAD characterized by two different tCM ***: Biochemical analysis revealed significant changes in tumor necrosis factor-α, high density lipoprotein cholesterol, blood stasis clinical symptoms observation, and Gensini levels in both patient groups post-PCI; Proteomic analysis identified 79 and 95 differentially expressed proteins in the QS and QD patient groups, respectively, compared to their control *** C8 alpha chain, complement factor H,apolipoprotein H, apolipoprotein B, plasminogen,carbonic anhydrase 2, and complement factor Ⅰ were altered in both comparison groups. Furthermore,enrichment analysis demonstrated that cell adhesion and connectivity-related processes underwent changes in QS patients post-PCI, whereas lipid metabolism-related pathways, including the peroxisome proliferator-activated receptor signaling pathway and extracellular matrix receptor interaction, underwent changes in the QD *** protein-protein interaction network analysis further enriched 52 node proteins, including apolipoprotein B,lipoprotein(a), complement C5, apolipoprotein A4,complement C8 alpha chain, complement C8 beta chain,complement C8 gamma chain, apolipoprotein H,apolipoprotein A-Ⅱ, albumin, complement C4-B,apolipoprotein C3, among others. the functional network of these proteins is posited to contribute t

关键词： traditional Chinese Medicine syndrome coronary atherosclerotic heart disease peptide mapping percutaneous coronary intervention proteomics

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