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Numerical simulation of formaldehyde distribution characteristics in the high-speed train cabin

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Building Simulation 2024年第2期17卷 285-300页

作者： Fan Wu Hang Dong Chao Yu Hengkui Li Qingmin Cui Renze Xu Key Laboratory of Traffic Safety on Track Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangshaHunan410075China Joint International Research Laboratory of Key Technologies for Rail Traffic Safety ChangshaHunan410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle ChangshaHunan410075China school of Software Henan University of EngineeringZhengzhouHenan451191China

The global concern over indoor air pollution in public vehicles has grown significantly.With a focus on enhancing passengers’comfort and health,this study endeavors to investigate the distribution characteristics of formaldehyde within a high-speed train cabin by employing a computational fluid dynamics(CFD)model which is experimentally validated in a real cabin scenario.The research focuses on analyzing the impact of air supply modes,temperature,relative humidity,and fresh air change rate on the distribution and concentration of formaldehyde.The results demonstrate that the difference in average formaldehyde concentration between the two air supply modes is below 1.3%,but the top air supply mode leads to a higher accumulation of formaldehyde near the sidewalls,while the bottom air supply mode promotes a more uniform distribution of formaldehyde.Furthermore,the temperature,relative humidity,and fresh air change rate are the primary factors affecting formaldehyde concentration levels,but they have modest effects on formaldehyde’s distribution pattern within the cabin.As the temperature and relative humidity increase,the changes in formaldehyde concentrations in response to variations in these factors become more evident.Importantly,the formaldehyde concentration may surpass the standard limit of 0.10 mg/m^(3)if the fresh air change rate falls below 212 m^(3)/h.This research provides a systematic approach and referenceable results for exploring formaldehyde pollution in high-speed train cabins.

关键词： indoor air pollution formaldehyde CFD simulation high-speed train ventilation

Electron-transporting boron-doped polycyclic aromatic hydrocarbons:Facile synthesis and heteroatom doping positions-modulated optoelectronic properties

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Chinese Chemical Letters 2024年第4期35卷 447-451页

作者： Tingting Huang Zhuanlong Ding Hao Liu Ping-An Chen Longfeng Zhao Yuanyuan Hu Yifan Yao Kun Yang Zebing Zeng Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Shenzhen Research Institute of hunan University Shenzhen 518000China Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education and hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices school of Physics and Electronics Hunan UniversityChangsha 410082China

While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.

关键词： Polycyclic aromatic hydrocarbon Optoelectronic properties Heteroatom doping n-Type organic semiconductors Structure–property relationship

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Multicolored Bipartite Ramsey Numbers of Large Cycles

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 347-357页

作者： Shao-qiang LIU Yue-jian PENG College of Mathematics and Statistics Hanshan Normal UniversityChaozhou 521041China school of Mathematics Hunan UniversityChangsha 410082China

For an integer r≥2 and bipartite graphs Hi,where 1≤i≤r,the bipartite Ramsey number br(H1,H2,…,Hr)is the minimum integer N such that any r-edge coloring of the complete bipartite graph KN;N contains a monochromatic subgraph isomorphic to Hi in color i for some 1≤i≤r.We show that if r≥3;α1,α2>0,αj+2≥[(j+2)!-1]Σi=1^(j+1)α1 for j=1,2…r-2,then br(C2[α1n],C2[α2n],…,C2[αrn]=(Σ=j=1^(r)a j+o(1))n.

关键词： ramsey number bipartite ramsey number regularity lemma

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2D multifunctional devices:from material preparation to device fabrication and neuromorphic applications

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International Journal of Extreme Manufacturing 2024年第3期6卷 91-118页

作者： Zhuohui Huang Yanran Li Yi Zhang Jiewei Chen Jun He Jie Jiang hunan Key Laboratory of Nanophotonics and Devices School of PhysicsCentral South UniversityChangshaHunanPeople’s Republic of China Department of Applied Physics The Hong Kong Polytechnic UniversityHong Kong Special Administrative Region of ChinaPeople’s Republic of China

Neuromorphic computing systems,which mimic the operation of neurons and synapses in the human brain,are seen as an appealing next-generation computing method due to their strong and efficient computing abilities.Two-dimensional (2D) materials with dangling bond-free surfaces and atomic-level thicknesses have emerged as promising candidates for neuromorphic computing hardware.As a result,2D neuromorphic devices may provide an ideal platform for developing multifunctional neuromorphic applications.Here,we review the recent neuromorphic devices based on 2D material and their multifunctional applications.The synthesis and next micro–nano fabrication methods of 2D materials and their heterostructures are first introduced.The recent advances of neuromorphic 2D devices are discussed in detail using different operating principles.More importantly,we present a review of emerging multifunctional neuromorphic applications,including neuromorphic visual,auditory,tactile,and nociceptive systems based on 2D devices.In the end,we discuss the problems and methods for 2D neuromorphic device developments in the future.This paper will give insights into designing 2D neuromorphic devices and applying them to the future neuromorphic systems.

关键词： 2D material micro–nano fabrication multifunctional system neuromorphic electronics artificial intelligence

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Synergistic Effect of Nitrogen/Phosphorus Co-Doping and Molybdenum Carbide Induced Electron Redistribution of Carbon Layer to Boost Hydrogen Evolution Reaction

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Chinese Journal of Chemistry 2024年第1期42卷 55-60页

作者： Jiamin Xiao Peng Li Yanyan Sun Heng Liu Javid Khan Handong Zhang Han Zhou Yaqiong Su Shuangyin Wang Lei Han College of Materials Science and Engineering Hunan Joint International Laboratory of Advanced Materials and Technology for Clean EnergyHunan UniversityChangshaHunan 410082China school of Chemistry Engineering Research Center of Energy Storage Materials and Devices Ministry of EducationXi'an Key Laboratory of Sustainable Energy Materials ChemistryState Key Laboratory of Electrical Insulation and Power EquipmentXi'an Jiaotong UniversityXi'anShaanxi 710049China school of Materials Science and Engineering Central South UniversityChangshaHunan 410083China state Key Laboratory of Chem/Bio-Sensingand Chemometrics College of Chemistry and Chemical EngineeringHunan University ChangshaHunan 410082China Laboratory of Inorganic Materials and Catalysis Department of Chemical Engineering and ChemistryEindhoven University of Technology P.O.Box5135600 MB EindhovenThe Netherlands

The development of highly efficient non-precious-metal-based electrocatalysts for the hydrogen evolution reaction is imperative for promoting the large-scale application of electrochemical water splitting.Herein,nitrogen/phosphorus co-doped carbon nanorods encapsulated Mo_(2)C nanoparticles(Mo_(2)C@PNc)have been prepared by pre-phosphating treatment in combination of the coordination with polydopamine and the subsequent pyrolysis.The phosphating temperature has a significant effect on the content of phosphorus within the resultant Mo_(2)C@PNC,and the optimal catalyst delivers superior HER activity with the low overpotential of 104 mV at a current density of 10 mAcm^(-2) and good stability for 8 h,which has been theoretically demonstrated to originate from the synergistic effect between P doping and Mo_(2)C induced electron redistribution of nitrogen-doped carbon layer.

关键词： Molybdenum carbide N/P co-doped carbon Hydrogen evolution Synergistic effect Electron redistribution Comprehensive

Multiple pretreatments can effectively improve the functionality of mesenchymal stem cells

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World Journal of Stem Cells 2024年第2期16卷 58-63页

作者： Xin-Xing Wan Xi-Min Hu Kun Xiong Department of Endocrinology Third Xiangya HospitalCentral South UniversityChangsha 410013Hunan ProvinceChina Department of Dermatology Xiangya HospitalCentral South UniversityChangsha 410008Hunan ProvinceChina Department of Anatomy and Neurobiology School of Basic Medical ScienceCentral South UniversityChangsha 410013Hunan ProvinceChina

In this editorial,we offer our perspective on the groundbreaking study entitled“Hypoxia and inflammatory factor preconditioning enhances the immunosup-pressive properties of human umbilical cord mesenchymal stem cells”,recently published in World Journal of Stem Cells.Despite over three decades of research on the clinical application of mesenchymal stem cells(MSCs),only a few therapeutic products have made it to clinical use,due to multiple preclinical and clinical challenges yet to be addressed.The study proved the hypoxia and inflammatory factor preconditioning led to higher immunosuppressive effects of MSCs without damaging their biological characteristics,which revealed the combination of inflammatory factors and hypoxic preconditioning offers a promising approach to enhance the function of MSCs.As we delve deeper into the intricacies of pretreat-ment methodologies,we anticipate a transformative shift in the landscape of MSC-based therapies,ultimately contributing to improved patient outcomes and advancing the field as a whole.

关键词： Mesenchymal stem cells Inflammatory factor Hypoxia Pretreatment

Association of Methionine Synthase rs1805087 Polymorphism With Arsenic-Related Skin Pigmentary Changes: A Population-Based Case-Control Study

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International Journal of Dermatology And Venereology 2024年第2期7卷 70-77页

作者： Huang Xiao-Yan Xiao Yi Jing Dan-Rong Shen Min-Xue Lu Li-Xia Department of Pathology Xiangya Hospital Central South University Changsha Hunan China Department of Dermatology Xiangya Hospital Central South University Changsha Hunan China hunan Key Laboratory of Skin Cancer and Psoriasis Central South University Changsha Hunan China hunan Engineering Research Center of Skin Health and Disease Central South University Changsha Hunan China Department of Social Medicine and Health Management Xiangya School of Public Health Central South University Changsha Hunan China.

Objective: Chronic arsenic exposure causes skin lesions including skin cancers, pigmentary changes, and keratosis. Genetic polymorphism in arsenic metabolism may increase susceptibility to the development of arsenic-related skin lesions. This study was performed to determine whether arsenic metabolism-related gene variants are associated with arsenic-related pigmentary changes.Methods: This case–control study involved 189 patients with arsenic-related pigmentary changes and 103 controls. Thirty-eight polymorphisms in 10 genes determined by mass spectrometry assay served as candidate drivers of arsenic-induced pigmentary changes. Urine and plasma arsenic levels were determined by inductively coupled plasma mass spectrometry. Hair arsenic concentrations were measured by nondispersive atomic fluorescence spectrometry. Arsenic metabolites in urine were determined using high-performance liquid chromatography with inductively coupled plasma mass spectrometry. Serum folate was measured using a folate radio assay kit. Analysis of variance, nonparametric test, or the chi-square test was selected according to the data distribution. Spearman correlation analysis was used to determine the correlation between two parameters. Logistic regression was used to estimate the effect of single-nucleotide polymorphisms.Results: The arsenic concentrations in urine, plasma, and hair and the urine arsenic species were not significantly different between patients and controls. Logistic regression revealed that among the polymorphisms, the methionine synthase (MTR) rs1805087 polymorphism showed a protective effect against arsenic-related pigmentary changes. In the codominant model, the adjusted odds ratio for age, sex, and ethnicity was 0.41 (95% confidence interval [CI], 0.21–0.80;P = 0.008) for the AG genotype and 0.11 (95%CI, 0.02–0.60;P = 0.012) for the GG genotype.Conclusion: MTR polymorphism showed a protective effect against arsenic-related pigmentary changes in the logistic regression model. The effect ofMTR rs1805087 might be inde

关键词： methionine synthase arsenic-related pigmentary changes arsenic metabolism

Anodic Electrosynthesis of Amide from Alcohol and Ammonia

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CCS Chemistry 2024年第1期6卷 125-136页

作者： Yuxuan Lu Yingying Li Bo Zhou Jingcheng Wu Ling Zhou Yuping Pan Zhongcheng Xia Ming Yang Yandong Wu Zhenran Yuan Rixin Peng Zhijie Kong Shuangyin Wang Yuqin Zou State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringAdvanced Catalytic Engineering Research Center of the Ministry of EducationHunan UniversityChangsha 410082 Shenzhen Institute of hunan University Shenzhen 518057 school of Chemistry and Chemical Engineering Jishou UniversityJishouHunan 416000

Amide is essential in biologically active compounds,synthetic materials,and building blocks.However,conventional amide production relies on energyintensive consumption and activating agents that modulate processes to construct the C–N bond.Herein,for the first time,we have successfully realized the formation of amides at industrial current density via the anodic coelectrolysis of alcohol and ammonia under ambient conditions.We have proved thatmodulation of the interface microenvironment concentration of nucleophile by electrolyte engineering can regulate the reaction pathways of amides rather than acetic acids.The C-N coupling strategy can be further extended to the electrosynthesis of the long-chain and aryl-ring amide with high selectivity by replacing ammonia with amine.Our work opens up a vast store of information on the utilization of biomass alcohol for high-value N-containing chemicals via an electrocatalytic C-N coupling reaction.

关键词： electrocatalysis electrocatalysts biomass upgrading elctrochemical oxidation coupling amide production

Concept, configuration, and application of on-board nanogrids for use in electric vehicles

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Science China Technological Sciences 2024年第7期67卷 2053-2073页

作者： ZHAO Bing LI Yong WU Fang WAN JiangHu CAI JiuQing YANG HaiTao LIU Fang College of Electrical and Information Engineering Hunan University Wuhan Second Ship Design and Research Institute school of Automation Central South University

Against the backdrop of increasingly serious climate change, researchers are attempting to extend macroscale carbon reduction research to smaller scales. With the rapid development and widespread application of electric vehicles(EVs), an effective approach for carbon reduction based on EVs has the potential to be developed. To coordinate and manage the EV platform in diverse application scenarios, the concept of an on-board nanogrid(OBNG), in which a nanogrid is combined with the EV, is proposed and defined, and the characteristics summarized. A configuration that includes a physical layer with the on-board hardware system; an information layer for logical control, energy management, and communication coordination; and an application layer that can cope with different working environments is proposed. A detailed introduction to the basic architecture and management mode of each layer is provided along with information concerning the relevant technologies for coordinated operation. New ideas and approaches to improve the existing performance are proposed, and finally, combined with a background of smart and low-carbon cities, major application scenarios are envisioned.

关键词： electric vehicle nanogrid energy management hybrid energy storage power electronics converter