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Chinese Chemical Letters 2007年第1期18卷 81-84页

作者： Jing xin Meng Ying Ma xin xin xu Yang Guang li En Bo Wang Key Laboratory of Polyoxometalate Science of Ministry of Education Department of Chemistry Northeast Normal University Ren Min Street No.5268 Changchun Jilin 130024 PR China

A new heteropolytungstate, [H2bpy]3[SiMnW11O39]· 1.25H2O （1）, has been prepared under mild hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. It is the first characterized compound containing ID zigzag chain of transition metal substituted Keggin heteropolytungstate, which is connected through a common oxygen atom. The elemental analysis and IR of it are also described.

关键词： Heteropolytungstate Keggin clusters Zigzag chain

Experimental Investigation on Vertical Hydraulic Transport of Ores in Deepsea Mining

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China Ocean Engineering 2024年第1期38卷 42-53页

作者： liU Lei liU Jian-cheng li xin xu li-xin ZHANG Xiu-zhan State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Sanya Yazhou Bay Institution of Deep-sea Sci-Tech Shanghai Jiao Tong UniversitySanya 572000China China Merchants Marine And Offshore Research Institute Co. Ltd.Shenzhen 518067China China Merchants Deepsea Research Institute(Sanya)Co. Ltd.Sanya 572000China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on *** hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial *** the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle *** hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow *** transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture *** qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were *** local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic *** effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.

关键词： deepsea mining vertical hydraulic transport experiment flow characteristics

A Rendezvous Mission to the Second Earth Trojan Asteroid 2020 XL_5 with Low-Thrust Multi-Gravity Assist Techniques

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Research in Astronomy and Astrophysics 2024年第1期24卷 245-264页

作者： Shi-Hai Yang Bo xu xin li School of Aeronautics and Astronautics Sun Yat-sen UniversityShenzhen 518107China

As the second of Earth's Trojan asteroids, 2020 XL_(5) is worthy of rendezvous and even sample return missions in many aspects. In this paper, a rendezvous mission to Earth's second Trojan asteroid 2020 XL_(5) is ***, due to its high inclination and large eccentricity, direct impulsive transfer requires large amounts of fuel consumption. To address this challenge, we explore the benefits of electric propulsion and multi-gravity assist techniques for interplanetary missions. These two techniques are integrated in this mission design. The design of a low-thrust gravity-assist(LTGA) trajectory in multi-body dynamics is thoroughly investigated,which is a complex process. A comprehensive framework including three steps is presented here for optimization of LTGA trajectories in multi-body dynamics. The rendezvous mission to 2020 XL_(5) is designed with this three-step approach. The most effective transfer sequence among the outcomes involves Earth–Venus–Earth–Venus-2020 XL_(5). Numerical results indicate that the combination of electric propulsion and multi-gravity assists can greatly reduce the fuel consumption, with fuel consumption of 9.03%, making it a highly favorable choice for this rendezvous mission.

关键词： minor planets asteroids:general celestial mechanics Planetary Systems

Traction force with extracellular matrix mediated by cytoskeleton influences metastasis through SLC8A1 induced Wnt-b-catenin pathway in endometrial cancer

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Genes & Diseases 2024年第5期11卷 98-101页

作者： xingchen li xin xu Jianliu Wang Department of Obstetrics and Gynecology Peking University People’s HospitalBeijing 100044China Department of Obstetrics and Gynecology Beijing ChaoYang HospitalCapital Medical UniversityBeijing 100020China

Endometrial cancer(EC)is one of the most prominent malignancies in ***,despite these advancements in understanding EC pathogenesis,mortality rates have not *** force(TF)refers to endogenous mechanical forces exerted by cells.1 These forces act on the extracellular matrix and the extracellular tumor microenvironment through focal adhesions,thereby regulating cell proliferation and ***,the TF characteristics of endometrial cancer cells and their heterogeneity remain unclear.

关键词： endometrial metastasis endogenous

Effect of proppant sizes and injection modes on proppant transportation and distribution in the tortuous fracture model

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Particuology 2024年第1期84卷 261-280页

作者： Jun li xu Han Siyuan He Mingyi Wu xin Huang Nianyin li State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China Chongqing Industry Polytechnic College Chongqing401120China Sichuan Particles Energy and Technology Co. LtdChengdu611630China Engineering Technology Research Institute of PetroChina Southwest Oil and Gas Field Company Chengdu610017China

Particle-fluid transport and placement mechanism in tortuous fracture played a crucial role in uncon-ventional ***,most studies focused on mono-size proppant with fluid transport pro-cesses in tortuous ***,the mixture-size proppant with fluid movement mechanism in tortuous fracture was still ***,this study designed and applied a series of experiments with a physical analog model of a tortuous fracture with 120°and 90°-angled bends and combined high-speed camera-based *** experimental system was used to track different-mixture-sized proppant particle motion trajectories for a series of proppant injection schemes;The following conclu-sions were drawn from this study:*** pile-up processes mechanism in all investigated schemes were similar and could be reduced to four main *** packing structure at both sides of the fracture wall had different variation rates,which were controlled by the mix ratio(change from 1∶1-1∶5)of proppant *** new packing patterns,such as Zebra Stripe,had occurred,controlled by the different proppant injection ***-sized mono-proppant(30/50 mesh)had the highest transport efficiency in the tortuous fracture,followed by the mixed-sized multi-proppant(10/20 mesh:30/50 mesh),large-sized proppant(10/20 mesh)was the *** optimized alternating in-jection mode was recommended as injecting small-sized proppant first(30/50 mesh)and followed by mixed-sized multi-proppant(10/20 mesh:30/50 mesh),which could contribute to obtaining the optimal both proppant packing height and travel distance in tortuous *** correlations were devel-oped for predicting the proppant packing height and transportation distance.

关键词： Tortuous fracture model Mixed-sized proppant Multi-sized proppant injection mode Proppant motion and distribution Packing mechanism

Wind-sand flow simulation and radius optimization of highway embankment under different vertical curve radius

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Journal of Mountain Science 2024年第8期21卷 2533-2546页

作者： li liangying li Qi WANG xu xin Guowei WANG Zhenqiang School of Civil Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

It is of great practical value to explore the correlation between the vertical curve radius of desert highway and the increase of sand accumulation in local lines,and to select the appropriate vertical curve radius for reducing the risk of sand *** this study,three-dimensional models of desert highway embankments with different vertical curve radii were constructed,and Fluent software was used to simulate the wind-sand flow field and sand accumulation distribution of vertical curve *** results show that:(1)Along the direction of the road,the concave and the convex vertical curve embankments have the effect of collecting and diverging the wind-sand flow,*** the radius of the concave vertical curve is 3000 m,5000 m,8000 m,10000 m and 20000 m,the wind velocity in the middle of the vertical curve is 31.76%,22.58%,10.78%,10.53%and 10.44%,higher than that at both *** the radius of the convex vertical curve is 6500 m,8000 m,10000 m,20000 m and 30000 m,the wind velocity at both ends of the vertical curve is 14.06%,9.99%,6.14%,3.22%and 2.41%,higher than that in the *** diversion effect also decreases with the increase of the radius.(2)The conductivity of the concave and convex vertical curve embankments with different radii is greater than 1,which is the sediment transport *** conductivity increases with the increase of radius and gradually tends to be *** the radius of the concave and convex vertical curves reaches 8000 m and 20000 m respectively,the phenomenon of sand accumulation is no longer *** the same radius condition,the concave vertical curve embankment is more prone to sand accumulation than the convex one.(3)Considering the strength of the collection and diversion of the vertical curve embankment with different radii,and the sand accumulation of the vertical curve embankment in the desert section of Wuma Expressway,the radius of the concave vertical curve is not less than 8000 m,and the r

关键词： Highway engineering Vertical curve Numerical simulation Embankment wind-sand flow Radius optimization

Microfluidic-oriented synthesis of enriched iridium nanodots/carbon architecture for robust electrocatalytic nitrogen fixation

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Green Energy & Environment 2024年第3期9卷 544-555页

作者： Hengyuan liu xingjiang Wu Yuhao Geng xin li Jianhong xu The State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing100084China

Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless ***,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic ***,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon *** to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption *** a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH ***,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) *** microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.

关键词： Iridium nanodots Carbon Microfluidic technology Efficient synthesis Electrocatalytic nitrogen fixation

Optimization of Gas Production from Hydrate-Bearing Sediments with Fluctuation Characteristics

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Journal of Ocean University of China 2024年第3期23卷 618-632页

作者： li Yaobin xu Tianfu xin xin YU Han YUAN Yilong ZHU Huixing Key Laboratory of Groundwater Resources and Environment Ministry of EducationJilin UniversityChangchun 130021China Jilin Provincial Key Laboratory of Water Resources and Environment Jilin UniversityChangchun 130021China

As an important source of low-carbon,clean fossil energy,natural gas hydrate plays an important role in improving the global energy consumption *** the hydrate industry in the South China Sea is important to achieving‘carbon peak and carbon neutrality’goals as soon as ***-water areas subjected to the action of long-term stress and tectonic movement have developed complex and volatile terrains,and as such,the morphologies of hydrate-bearing sediments(HBSs)fluctuate *** key to numerically simulating HBS morphologies is the establishment of the conceptual model,which represents the objective and real description of the actual geological ***,current numerical simulation models have characterized HBSs into horizontal strata without considering the fluctuation *** representing the HBS as a horizontal element reduces simulation ***,the commonly used horizontal HBS model and a model considering the HBS’s fluctuation characteristics with the data of the SH2 site in the Shenhu Sea area were first constructed in this ***,their production behaviors were compared,and the huge impact of the fluctuation characteristics on HBS production was *** this basis,the key parameters affecting the depressurization production of the fluctuating HBSs were studied and *** research results show that the fluctuation characteristics have an obvious influence on the hydrate production of HBSs by affecting their temperatures and pressure distributions,as well as the transmission of the pressure drop and methane gas ***,the results show that the gas productivity of fluctuating HBSs was about 5%less than that of horizontal *** optimizing the depressurization amplitude,well length,and layout location of vertical wells,the productivity of fluctuating HBSs increased by about 56.6%.

关键词： natural gas hydrate numerical simulation fluctuation characteristics depressurization production production well optimization

Safe Efficient Policy Optimization Algorithm for Unsignalized Intersection Navigation

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IEEE/CAA Journal of Automatica Sinica 2024年第9期11卷 2011-2026页

作者： Xiaolong Chen Biao xu Manjiang Hu Yougang Bian Yang li xin xu State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body the College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body the College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082 Wuxi Intelligent Control Research Institute(WICRI)of Hunan University Wuxi 214115China College of Intelligence Science and Technology Institute of Unmanned SystemsNational University of Defense TechnologyChangsha 410073China

Unsignalized intersections pose a challenge for autonomous vehicles that must decide how to navigate them safely and *** paper proposes a reinforcement learning(RL)method for autonomous vehicles to navigate unsignalized intersections safely and *** method uses a semantic scene representation to handle variable numbers of vehicles and a universal reward function to facilitate stable learning.A collision risk function is designed to penalize unsafe actions and guide the agent to avoid them.A scalable policy optimization algorithm is introduced to improve data efficiency and safety for vehicle learning at *** algorithm employs experience replay to overcome the on-policy limitation of proximal policy optimization and incorporates the collision risk constraint into the policy optimization *** proposed safe RL algorithm can balance the trade-off between vehicle traffic safety and policy learning *** intersection scenarios with different traffic situations are used to test the algorithm and demonstrate its high success rates and low collision rates under different traffic *** algorithm shows the potential of RL for enhancing the safety and reliability of autonomous driving systems at unsignalized intersections.

关键词： Autonomous driving decision-making reinforcement learning(RL) unsignalized intersection

Profiling B and T cell immune responses to co-infection of Mycobacterium tuberculosis and hookworm in humans

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Infectious Diseases of Poverty 2015年第1期4卷 133-142页

作者： xin-xu li Jia-xu Chen li-Xia Wang Jun Sun Shao-Hong Chen Jun-Hu Chen Xiao-Yan Zhang Xiao-Nong Zhou National Institute of Parasitic Diseases Chinese Center for Disease Control and PreventionKey Laboratory of Parasite and Vector BiologyMinistry of HealthWHO Collaborating Centre for MalariaSchistosomiasis and Filariasis207 Rui Jin Er RoadHuangpu DistrictShanghai 200025PR China(PRC) National Center for Tuberculosis Control and Prevention Chinese Center for Disease Control and PreventionBeijing 102206PR China Shanghai Public Health Clinical Center Key Laboratory of Medical Molecular Virology of Ministry of EducationInstitutes of Biomedical SciencesFudan UniversityShanghai 201508PR China

Background:Humoral and cellular immune responses play protective roles against Mycobacterium tuberculosis(MTB)***,hookworm infection decreases the immune response to hookworm and bystander ***,immune responses to co-infection of MTB and hookworm are still unknown,although co-infection has been one of the public health problems in co-endemic areas of pulmonary tuberculosis(PTB)and hookworm ***,it is essential to evaluate B and T cell immune responses to the ***:Seventeen PTB cases co-infected with hookworm,26 PTB cases,15 patients with hookworm infection,and 24 healthy controls without PTB or hookworm infection were enrolled in the *** of CD3,CD4,CD8,CD10,CD19,CD20,CD21,CD25,CD27,CD38,FoxP3,and PD-1 were assessed on B and T cell subsets using multicolor flow ***:For the B cell(CD19+)subsets,naïve B cells(CD10−CD27−CD21+CD20+),plasma cells(CD10−CD27+CD21−CD20−),and tissue-like memory B cells(CD10−CD27−CD21−CD20+)had higher proportions,whilst resting memory B cells(CD10−CD27+CD21+CD20+)had lower proportions in the group co-infected with MTB and hookworm as compared to other *** of activated memory B cells(CD10−CD27+CD21−CD20+)did not differ among the four *** the T cell(CD3+)subsets,frequencies of regulatory T cells(CD4+CD25+Foxp3+)and exhausted CD4+and CD8+T cells(CD4+PD-1+and CD8+PD-1+)were higher,and frequencies of activated CD4+and CD8+T cells(CD4+CD38+and CD8+CD38+)were lower in the co-infected group as compared to the other ***:The change patterns of the cell profile of circulating lymphocytes were indentified in human co-infection of MTB and hookworm,which might indicate that the humoral and cellular immune responses are more suppressed.

关键词： Co-infection Mycobacterium tuberculosis Hookworm Immune response