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Pedestrian flow through exit:Study focused on evacuation pattern

Chinese Physics B 2024年第1期33卷 755-764页

作者：张博思余志红孙柏林郭紫钰陈默 School of Safety Engineering China University of Labor RelationsBeijing 100048China

Experiments are conducted on the evacuation rate of pedestrians through exits with queued evacuation pattern and random evacuation pattern. The experimental results show that the flow rate of pedestrians is larger with the random evacuation pattern than with the queued evacuation pattern. Therefore, the exit width calculated based on the minimum evacuation clear width for every 100 persons, which is on the assumption that the pedestrians pass through the exit in one queue or several queues, is conservative. The number of people crossing the exit simultaneously is greater in the random evacuation experiments than in the queued evacuation experiments, and the time interval between the front row and rear row of people is shortened in large-exit conditions when pedestrians evacuate randomly. The difference between the flow rate with a queued evacuation pattern and the flow rate with a random evacuation pattern is related to the surplus width of the exit, which is greater than the total width of all accommodated people streams. Two dimensionless quantities are defined to explore this relationship. It is found that the difference in flow rate between the two evacuation patterns is stable at a low level when the surplus width of the exit is no more than 45% of the width of a single pedestrian stream. There is a great difference between the flow rate with the queued evacuation pattern and the flow rate with the random evacuation pattern in a scenario with a larger surplus width of the exit. Meanwhile, the pedestrians crowd extraordinarily at the exit in these conditions as well, since the number of pedestrians who want to evacuate through exit simultaneously greatly exceeds the accommodated level. Therefore, the surplus width of exit should be limited especially in the narrow exit condition, and the relationship between the two dimensionless quantities mentioned above could provide the basis to some extent.

关键词： evacuation exit width flow rate queued evacuation pattern random evacuation pattern

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Microstructural development of vanadium-nickel crystalline alloy membranes

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Rare Metals 2021年第7期40卷 1932-1939页

作者： Peng Jiang Xiao-Bin Shi bo-lin sun Hai-Chuan Wang Michael Doland Guang-Sheng Song School of Materials Science and Engineering Anhui University of TechnologyMaanshan 243002China School of Mechanical Engineering Changzhou UniversityChangzhou 213164China School of Metallurgical Engineering Anhui University of TechnologyMaanshan 243002China CSIRO Energy.Queensland Centre for Advanced TechnologiesPullenvale 4069Australia

V85Ni15(at%)alloy was proposed as a promising candidate for hydrogen separation *** date,investigations of V85Ni15 alloy have concentrated on hydrogen permeation characteristics,and little work has been done on the microstructural *** the present study,various fabrication and heat-treatment techniques were used to develop different microstructures which would then be tailored to achieve a desired candidate for acceptable mechanical stability while maintaining high hydrogen *** arc-melted(AM)V85Ni15 alloy are supersaturated solid solution with dendritic segregation of Ni-solute *** rolling(CR)followed by annealing at 1050℃and 850℃can produce a two-phase(V+σ)microstructure and a three-phase(V+σ+NiV3)microstructure,*** fine two-phase microstructure obtained at 1050℃involves a simultaneous reaction of second-phase precipitation and V-matrix *** phase is formed via primary precipitation,while NiV3 phase is formed by peritectoidal *** AMCR samples were homogenized at1250℃for 2 h and sequential heat-treated at 850℃or900℃for 2 h,precipitation-strengthening microstructure is obtained:large grain structure of V-matrix with uniform distribution of second-phase particles produced by recrystallization and grain growth followed by precipitation process.

关键词： Microstructure characterization Alloy membrane V-Ni alloy Deformation Recrystallization Solid transformation

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Advances in Polymeric Carbon Nitride Photocatalysts for Enhanced CO_(2)Reduction

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China Petroleum Processing & Petrochemical Technology 2024年第2期26卷 1-12页

作者： Liu Bing sun Shangcong Song Ye Peng bo lin Wei SINOPEC Research Institute of Petroleum Processing Co. Ltd.Beijing100083China

Photocatalysis has emerged as a promising alternative for converting and utilizing CO_(2).Polymeric carbon nitride(PCN),typically synthesized through the one-step thermal polycondensation of nitrogen-rich precursors,has shown considerable promise due to its adjustable band structure and inherent *** the past five years,significant literature in this field has identified five primary methods for modifying PCN:morphology modulation,element doping,defect induction,co-catalyst loading,and heterojunction construction.A detailed discussion on how each modification method influences light absorption,charge separation,and surface reaction efficiencies in photocatalysis is *** on these findings,several future directions for the development of PCN-based materials are proposed,such as designing tailored PCN structures for specific photocatalytic reactions and using theoretical calculations to verify and correct results from current characterization *** the challenges associated with the large-scale synthesis of PCN materials with controllable structures and satisfactory performance,this work offers valuable insights for advancing photocatalytic PCN-based systems for large-scale solar fuel production.

关键词： carbon nitride photocatalysis CO_(2)reduction modification

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Catalysis by subsurface metal atoms in Al(001) through electron transfer

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National Science Review 2024年第4期11卷 12-13页

作者： bo sun Ding Ma Beijing National Laboratory for Molecular Science New Cornerstone Science Laboratory College of Chemistry and Molecular Engineering Peking University

Heterogeneous catalysis plays a crucial role in the chemical industry, which has evolved from the investigation of chemisorption to an electronic structure[1]. Diverse strategies, such as alloying,doping, and confining, have been applied to enhance the catalytic properties of active sites through electronic modulation. The electron transfer between active sites and substrates profoundly influences catalytic activity [2].

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Catalytic recycling of polyesters via a binuclear catalyst

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Science China Chemistry 2024年第2期67卷 426-427页

作者： bo sun Ding Ma Beijing National Laboratory for Molecular Science New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

Plastics play a crucial role in modern society life. While the increasing use of plastics and rapid accumulation of plastic waste in nature environment have caused severe environmental crisis and the waste of carbon resources. Catalytic upcycling is a promising approach to transform plastic waste into high value-added chemicals to achieve a sustainable circular economy.

关键词： Catalytic polyester catalyst

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Cross section determination of^(27)Al(n,2n)^(26)Al reaction induced by 14-MeV neutrons uniting with D-T neutron activation and AMS techniques

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Nuclear Science and Techniques 2024年第6期35卷 78-89页

作者： Xian-lin Yang Chang-lin Lan Yu-Ting Wei Yi Zhang Gong Jiang bo Xie Yu Liu Hong-Tao Shen Xiao-Jun sun School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China MOE Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology Guangxi Normal UniversityGuilin 541004China

Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great *** address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion *** the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He ***^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of *** neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb *** measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature *** newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental *** obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.

关键词： 14-MeV neutron ^(27)Al(n,2n)^(26)Al Cross section AMS

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Effect and Mechanism of Rare Earth Hydrotalcite Inhibiting Coal Spontaneous Combustion

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 50-59页

作者：张小娟 LIU bo 罗振敏 sun Lu School of Safety Science and Engineering Xi’an University of Science and TechnologyXi’an 710054China

A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.

关键词： rare earth hydrotalcite coal spontaneous combustion mechanism

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Forced boiling of nonazeotropic immiscible mixture in a supercapillary microchannel array for ultra-high heat flux removal with chip junction temperature below 85℃

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Science China(Technological Sciences) 2024年第5期67卷 1364-1380页

作者： sun bo BAO YuChen TIAN Tong LI Ji School of Engineering Science University of Chinese Academy of SciencesBeijing100049China Laboratory of Advanced Thermal Management Technologies School of Engineering ScienceUniversity of Chinese Academy of SciencesBeijing100049China

In this study,a structure-optimized two-phase microchannel heat sink with sintered submicron nucleation sites was developed and *** copper-based microchannels had a rectangular cross-section with an equivalent hydraulic diameter of 222μ*** subcooled flow boiling characteristics were comprehensively compared between pure HFE-7100 and a non-azeotropic,immiscible binary mixture of HFE-7100 and water,considering heating areas of 1 and 5 cm^(2).The total heating power input to the test section were 100–1500 and 250–3000 W for a 1 and 5 cm^(2)heat source,respectively,with a flow rate ranging from 50 to150 L/*** to pure HFE-7100,the non-azeotropic immiscible binary mixture of HFE-7100/water in the sintered porous microchannels exhibited a much higher overall heat transfer coefficient and lower power *** maintain the junction temperature of a high power electronic chip below 85℃,the proposed supercapillary microchannel heat sink could effectively dissipate the heat flux of 1275 W/cm^(2)over 1 cm^(2)heat source and 500 W/cm^(2)over 5 cm^(2)heat *** addition,the volume ratio of the binary mixture strongly influence the two-phase flow heat transfer *** optimal volume ratio exist in terms of the thermal resistance–pumping power minimization(HFE-7100:water=2:8 is recommended in this study).The findings of this investigation on the flow boiling properties of non-azeotropic immiscible mixtures help fill a gap in the related field.

关键词： microchannel sintered powder coating submicron nucleation cavities nonazeotropic immiscible ultra-high heat flux

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Neddylation Regulation of Immune Responses

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Research 2024年第3期2023卷 545-559页

作者： Hongmei Mao Xin lin Yi sun Cancer Institute(Key Laboratory of Cancer Prevention and Intervention China National Ministry of Education)of the Second Affiliated Hospital and Institute of Translational MedicineZhejiang University School of MedicineHangzhou 310029China Institute for Immunology School of MedicineTsinghua UniversityBeijing 100084China Changping Laboratory Beijing 102206China Cancer Center of Zhejiang University Hangzhou 310029China Zhejiang Provincial Clinical Research Center for Cancer HangzhouZhejiang ProvinceChina Key Laboratory of Molecular Biology in Medical Sciences HangzhouZhejiang ProvinceChina Research Center for Life Science and Human Health Binjiang Institute of Zhejiang UniversityHangzhou 310053China.

Neddylation plays a vital role in post-translational modification, intricately shaping the regulation of diverse biological processes, including those related to cellular immune responses. In fact, neddylation exerts control over both innate and adaptive immune systems via various mechanisms. Specifically, neddylation influences the function and survival of innate immune cells, activation of pattern recognition receptors and GMP-AMP synthase–stimulator of interferon genes pathways, as well as the release of various cytokines in innate immune reactions. Moreover, neddylation also governs the function and survival of antigen-presenting cells, which are crucial for initiating adaptive immune reactions. In addition, neddylation regulates T cell activation, proliferation, differentiation, survival, and their effector functions, thereby ensuring an appropriate adaptive immune response. In this review, we summarize the most recent findings in these aspects and delve into the connection between dysregulated neddylation events and immunological disorders, especially inflammatory diseases. Lastly, we propose future directions and potential treatments for these diseases by targeting neddylation.

关键词： activation thereby initiating

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Binary prodrug nanoassemblies combining chemotherapy and ferroptosis activation for efficient triple-negative breast cancer therapy

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Chinese Chemical Letters 2024年第10期35卷 348-352页

作者： lin Li Bingjun sun jin sun lin Chen Zhonggui He Department of Pharmacy Women and Children's Hospital of Chongqing Medical University/Chongqing Health Center for Women and ChildrenChongqing 401147China Department of Pharmaceutics Wuya College of InnovationShenyang Pharmaceutical UniversityShenyang 110016China

Chemotherapy has been recommended as the standard protocol for triple-negative breast cancer(TNBC)at the advanced ***,the current treatment is unsatisfactory due to inefficient drug accumulation and rapid ***,rational design of advanced drug delivery systems that can induce multiple cell death pathways is a promising strategy to combat *** is a powerful non-apoptotic cell death modality,showing potential in tumor ***,we propose a binary prodrug nanoassemblies that combines chemotherapy with ferroptosis for TNBC *** this system,paclitaxel is linked with paracetamol(ferroptosis activator)by a disulfide linkage to construct self-assembly ***,2-distearoyl-sn-glycerol-3-phosphoethanolamine-N-methyl(polyethylene glycol)-2000-tyrosine(DSPE-PEG2k-tyrosine)is applied for large neutral amino acid transporter 1(LAT1)targeting,which is highly expressed in *** prodrug nanoassemblies exhibit good stability and a glutathione(GSH)-responsive release ***,the LAT1-targeted nanoassemblies show stronger cytotoxicity,higher cellular uptake,and more obvious ferroptosis activation than non-decorated *** a TNBC mice model,the prodrug nanoassemblies demonstrate strong anti-tumor *** application of ferroptosis-assisting chemotherapy may provide a promising strategy for TNBC therapy.

关键词： Prodrug nanoassemblies Paclitaxel Ferroptosis LAT1 Triple-negative breast cancer

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