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Towards mesoscopic ergodic theory

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Science China Mathematics 2020年第9期63卷 1853-1876页

作者： Weiwei qi Zhongwei shen Shirou Wang Yingfei Yi Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Mathematical and Statistical Sciences University of AlbertaEdmontonAB T6G 2G1Canada School of Mathematics Jilin UniversityChangchun 130012China

The present paper is devoted to a preliminary study towards the establishment of an ergodic theory for stochastic di erential equations(SDEs)with less regular coecients and degenerate *** equations are often derived as mesoscopic limits of complex or huge microscopic *** studying the associated Fokker-Planck equation(FPE),we prove the convergence of the time average of globally de ned weak solutions of such an SDE to the set of stationary measures of the FPE under Lyapunov *** the case where the set of stationary measures consists of a single element,the unique stationary measure is shown to be *** convergence results for the solutions of the FPE are established as *** of our convergence results,while being special cases of those contained in Ji et al.(2019)for SDEs with periodic coecients,have weaken the required Lyapunov conditions and are of much simpli ed *** to stochastic damping Hamiltonian systems and stochastic slow-fast systems are given.

关键词： ergodic theory stochastic di erential equation Fokker-Planck equation stationary measure physical measure mesoscopic limit

Cross-talk between the thyroid and liver:A new target for nonalcoholic fatty liver disease treatment

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World Journal of Gastroenterology 2013年第45期19卷 8238-8246页

作者： Yue-Ye Huang Aaron M Gusdon shen qu Department of Endocrinology and Metabolism Shanghai 10th People’s Hospital School of Medicine Tongji University Department of Neurology and Neuroscience Weill Cornell Medical College New York NY 10065 United States Department of Endocrinology and Metabolism Nanjing Medical University

Nonalcoholic fatty liver disease(NAFLD)has been recognized as the most common liver metabolic disease,and it is also a burgeoning health problem that affects one-third of adults and is associated with obesity and insulin resistance *** hormone(TH)and its receptors play a fundamental role in lipid metabolism and lipid accumulation in the *** is found that thyroid receptor and its isoforms exhibit tissue-specific expression with a variety of ***β1 is predominantly expressed in the brain and adipose tissue and TRβ2 is the major isoform in the liver,kidney and *** have different functions and play important roles in lipid ***,there are many studies on the treatment of NAFLD with TH and its *** review here that thyroid hormone and TR are a potential target for pharmacologic *** metabolism and lipid accumulation can be regulated and reversed by TH and its analogues.

关键词： Thyroid hormone Thyroid hormone receptor Nonalcoholic fatty liver disease Obesity

Spatio-temporal flow maps for visualizing movement and contact patterns

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Visual Informatics 2017年第1期1卷 57-64页

作者： Bing Ni qiaomu shen Jiayi Xu Huamin qu Department of Computer Science and Engineering Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong Noah’s Ark Lab Huawei TechnologiesRoom 525-530Core Building 2HKSPShatinHong Kong

The advanced telecom technologies and massive volumes of intelligent mobile phone users have yielded a huge amount of real-time data of people’s all-in-one telecommunication records,which we call telco big *** telco data and the domain knowledge of an urban city,we are now able to analyze the movement and contact patterns of humans in an unprecedented *** map is widely used to display the movements of humans from one single source to multiple destinations by representing locations as nodes and movements as ***,it fails the task of visualizing both movement and contact *** addition,analysts often need to compare and examine the patterns side by side,and do various quantitative *** this work,we propose a novel spatio-temporal flow map layout to visualize when and where people from different locations move into the same places and make *** also propose integrating the spatiotemporal flow maps into existing spatiotemporal visualization techniques to form a suite of techniques for visualizing the movement and contact *** report a potential application the proposed techniques can be applied *** results show that our design and techniques properly unveil hidden information,while analysis can be achieved efficiently.

关键词： Spatio-temporal data Flow map Urban mobility

Theoretical design and preparation of high thermal-stable jet fuel

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Science China Chemistry 2008年第2期51卷 138-144页

作者： LIU GuoZhu qu HaiJie shen HuiMing ZHANG XiangWen MI ZhenTao Key Lab of Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

A high thermal-stable jet fuel design method was developed using composition-properties relations and basic specification properties of jet fuel. Tannery diagrams were provided to visualize relationships among three main components (n-paraffins, iso-paraffins, cycloparaffins, or aromatics) with four major specification properties (density, flash point, freezing point, net heat of combustion) and thermal sta- bility. An optimum chemical composition was established to meet performance requirements: n-paraffins 25%-45%, iso-paraffins 15%-30%, cycloparaffins 30%-50%, and aromatics 5%. The thermal stability test on four fuel samples with and without optimal composition indicated that the thermal stabilities of fuel samples with optimal composition are higher than RP-3 jet fuel, and that the theoretical design method is a reliable method to screen the basic oil for the high thermal-stable jet fuel.

关键词： jet fuel thermal stability composition-property relations composition design

Microstructure characterization of a pressureless infiltrating oxidized SiCp preform by Al-8Mg

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International Journal of Minerals,Metallurgy and Materials 2011年第2期18卷 223-228页

作者： Shu-bin Ren Xiao-yu shen Xin-bo He Xuan-hui qu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The microstructure of a pressureless infiltrating 55vol% oxidized SiC preform by Al-8Mg alloy was characterized by transmission electron microscopy （TEM）, high resolution TEM （HRTEM）, field emission scanning electron microscopy （FE-SEM）, and X-ray diffraction. The TEM image of the interface between Al and SiC shows that the surface of SiC is covered by a rough nanocrystal layer of MgAl2O4, Al2O3, and Si, produced by the interfacial reaction of Al, Mg, and SiO2 on the surface of SiC. The Al-SiC interface is also examined by HRTEM to be better understood how MgAl2O4 and Al2O3 are produced. Dendritic Al2O3 crystals are embedded in the pores of the composite generated from the mutual bonding of SiO2 on the surface of SiC. Columnar AlN crystals of about 250 nm in length are bunched vertically on the SiC particle surface.

关键词： microstructure composites interfaces pressureless infiltration oxidation.

A method to model the effect of pre-existing cracks on P-wave velocity in rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 493-506页

作者： Haimeng shen Xiaying Li qi Li Haibin Wang State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

Crack closure is one of the reasons inducing changes of P-wave velocity of rocks under *** this context,a method is proposed to investigate the relationships among P-wave velocity,pre-existing cracks,and confining pressure based on the discrete element method(DEM).Pre-existing open cracks inside the rocks are generated by the initial gap of the flat-joint *** validity of the method is evaluated by comparing the P-wave velocity tested on a sandstone specimen with numerical *** the crack size is determined by the diameter of particles,the effects of three factors,***,aspect ratio,and orientation of cracks on the P-wave velocity are *** results show that P-wave velocity is controlled by the(***) of open micro-cracks,while the closure pressure is determined by the aspect ratio of *** reason accounting for the anisotropy of P-wave velocity is the difference in crack number in measurement *** of the number and aspect ratio of cracks can affect the responses of P-wave velocity to the applied confining *** confining pressure,the number of open cracks inside rocks will dominate the lowest P-wave velocity,and the P-wave velocity of the rock containing narrower cracks is more sensitive to the confining *** this sense,crack density is difficult to be back-calculated merely by P-wave *** proposed method offers a means to analyze the effect of pre-existing cracks on P-wave velocity.

关键词： Pre-existing cracks P-wave velocity Discrete element method(DEM) Anisotropic rock

Constructing supramolecular polymers from phototrigger containing monomer

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Chinese Chemical Letters 2018年第11期29卷 1621-1624页

作者： Xiuli Zheng qi Miao Wenzhi Wang Da-Hui qu Key Laboratory for Advanced Materials and Institute of Fine Chemicals School of Chemistry and Molecular EngineeringEast China University of Science &Technology

A new type of photo-induced supramolecular polymer was fabricated by host-guest interaction from a phototrigger containing building block. A dibenzo-24-crown-8 （DB24C8） macrocycle and dibenzylammonium （DBA） site containing linear monomer was designed and synthesized. The coumarin, as a photocleavable protector, was introduced to the terminal of the monomer. When exposed to the UV light, the coumarin unit would be cleavaged and the monomer without terminal coumarin can self-assemble into supramolecular polymers via the host-guest interaction between DB24C8 moieties and DBA units. Increasing the concentration of the monomer, the supramolecular polymers will convert to supramolecular organogel by cross-linking with each other.

关键词： Supramolecular polymer Host-guest recognition Photo-responsive Crown ether

On‑Ramp Merging for Highway Autonomous Driving:An Application of a New Safety Indicator in Deep Reinforcement Learning

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Automotive Innovation 2023年第3期6卷 453-465页

作者： Guofa Li Weiyan Zhou Siyan Lin shen Li Xingda qu College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China Institute of Human Factors and Ergonomics College of Mechatronics and Control EngineeringShenzhen University3688 Nanhai AvenueShenzhen 518060Guangdong ProvinceChina School of Civil Engineering Tsinghua UniversityBeijing 100084China

This paper proposes an improved decision-making method based on deep reinforcement learning to address on-ramp merging challenges in highway autonomous driving.A novel safety indicator,time difference to merging(TDTM),is introduced,which is used in conjunction with the classic time to collision(TTC)indicator to evaluate driving safety and assist the merging vehicle in finding a suitable gap in traffic,thereby enhancing driving *** training of an autonomous driving agent is performed using the Deep Deterministic Policy Gradient(DDPG)*** action-masking mechanism is deployed to prevent unsafe actions during the policy exploration *** proposed DDPG+TDTM+TTC solution is tested in on-ramp merging scenarios with different driving speeds in SUMO and achieves a success rate of 99.96%without significantly impacting traffic efficiency on the main *** results demonstrate that DDPG+TDTM+TTC achieved a higher on-ramp merging success rate of 99.96%compared to DDPG+TTC and DDPG.

关键词： Autonomous driving On-ramp merging Deep reinforcement learning Action-masking mechanism Deep Deterministic Policy Gradient(DDPG)

A novel magnetic silica supported spinel ferrites NiFe2O4 catalyst for heterogeneous Fenton-like oxidation of rhodamine B

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Chinese Chemical Letters 2019年第6期30卷 1198-1203页

作者： Jifeng qu Tinghua Che Libin Shi qinghua Lu Suitao qi School of Chemical Engineering and Technology Xi’an Jiaotong University

A series of spinel fe rrites magnetic nanopa rticles NiFe2 O4 we re synthesized as the heterogeneous Fentonlike catalyst by hydrothermal method and then NiFe2 O4@SiO2 catalysts were obtained by the modification of NiFe2 O4 via micro emulsion ***,VSM,FTIR,SEM,TEM,BET and XPS were carried to analyze the difference between the above two ***2 O4@SiO2 catalyst exhibited the higher catalytic activity than NiFe2 O4 for the degradation of Rhodamine B owe to the outer Si02 layers surface,the more important is both of them showed the better catalytic performance when at neutral pH environment.

关键词： Heterogeneous Fenton-like oxidation Spinel ferrites Magnetic Synthesis Neutral environment