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Two-step high-pressure high-temperature synthesis of nanodiamonds from naphthalene

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Chinese Physics B 2020年第10期29卷 515-520页

作者： Tong Liu Xi-Gui Yang Zhen Li Yan-Wei Hu chao-fan lv Wen-Bo Zhao Jin-Hao Zang Chong-Xin Shan Henan Key Laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Materials PhysicsMinistry of EducationSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China

Nanodiamonds have outstanding mechanical properties,chemical inertness,and biocompatibility,which give them potential in various *** methods for preparing nanodiamonds often lead to products with impurities and uneven *** report a two-step high-pressure high-temperature(HPHT) method to synthesize nanodiamonds using naphthalene as the precursor without metal *** grain size of the diamonds decreases with increasing carbonization time(at constant pressure and temperature of 11.5 GPa and 700℃,respectively).This is discussed in terms of the different crystallinities of the carbon *** probability of secondary anvil cracking during the HPHT process is also *** results indicate that the two-step method is efficient for synthesizing nanodiamonds,and that it is applicable to other organic precursors.

关键词： nanodiamonds high pressure high temperature phase transition naphthalene

Self-exothermic reaction driven large-scale synthesis ofphosphorescent carbon nanodots

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Nano Research 2021年第7期14卷 2231-2240页

作者： Shi-Yu Song Lai-Zhi Sui Kai-Kai Liu Qing Cao Wen-Bo Zhao Ya-Chuan Liang chao-fan lv Jin-Hao Zang Yuan Shang Qing Lou Xi-Gui Yang Lin Dong Kai-Jun Yuan Chong-Xin Shan Henan Key Laboratory of Diamond Optoelectronic Materials and Devices School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical PhysicsChinese Academy of Sciences457 Zhongshan RoadDalian 116023China Super Computer Center Smart City InstituteZhengzhou UniversityZhengzhou 450001China

Phosphorescent carbon nanodots(CNDs)have various attractive properties and potential applications,but it remains a formidable challenge to achieve large-scale phosphorescent CNDs limited by current ***,a large-scale synthesis method for phosphorescent CNDs has been demonstrated via precursors’self-exothermic reaction at room *** as-prepared CNDs show fluorescence and phosphorescence property,which are comparable with that synthesized by solvothermal and microwave *** and computational studies indicate that exotic atom doped sp^(2) hybridized carbon core works as an emissive center,which facilities the intersystem crossing from singlet state to triplet *** CNDs show phosphorescence with tunable lifetimes from 193 ms to 1.13 s at different *** demonstration of large-scale synthesis of phosphorescent CNDs at room temperature opens up a new window for room temperature fabrication phosphorescent CNDs.

关键词： carbon nanodots phosphorescence large scale self-exothermic reaction

Human neural stem cell-derived extracellular vesicles protect against ischemic stroke by activating the PI3K/AKT/mTOR pathway

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Neural Regeneration Research 2025年第11期20卷 3245-3258页

作者： Jiayi Wang Mengke Zhao Dong Fu Meina Wang chao Han Zhongyue lv Liang Wang Jing Liu Stem Cell Clinical Research Center The First Affiliated Hospital of Dalian Medical UniversityDalianLiaoning ProvinceChina Dalian Innovation Institute of Stem Cell and Precision Medicine DalianLiaoning ProvinceChina Institute(College)of Integrative Medicine Dalian Medical UniversityDalianLiaoning ProvinceChina

Human neural stem cell-derived extracellular vesicles exhibit analogous functions to their parental cells,and can thus be used as substitutes for stem cells in stem cell therapy,thereby mitigating the risks of stem cell therapy and advancing the frontiers of stem cell-derived *** lays a foundation for the development of potentially potent new treatment modalities for ischemic ***,the precise mechanisms underlying the efficacy and safety of human neural stem cell-derived extracellular vesicles remain unclear,presenting challenges for clinical *** promote the translation of therapy based on human neural stem cell-derived extracellular vesicles from the bench to the bedside,we conducted a comprehensive preclinical study to evaluate the efficacy and safety of human neural stem cell-derived extracellular vesicles in the treatment of ischemic *** found that administration of human neural stem cell-derived extracellular vesicles to an ischemic stroke rat model reduced the volume of cerebral infarction and promoted functional recovery by alleviating neuronal *** human neural stem cell-derived extracellular vesicles reduced neuronal apoptosis by enhancing phosphorylation of phosphoinositide 3-kinase,mammalian target of rapamycin,and protein kinase B,and these effects were reversed by treatment with a phosphoinositide 3-kinase *** findings suggest that human neural stem cell-derived extracellular vesicles play a neuroprotective role in ischemic stroke through activation of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin signaling ***,we showed that human neural stem cell-derived extracellular vesicles have a good in vivo safety ***,human neural stem cell-derived extracellular vesicles are a promising potential agent for the treatment of ischemic stroke.

关键词： behavior exosome extracellular vesicles ischemic stroke mammalian target of rapamycin(mTOR) middle cerebral artery occlusion neural stem cells neuronal apoptosis phosphoinositide 3-kinase(PI3K) protein kinase B(AKT)

单原子Pt负载在锐钛矿(001)表面的电光学特性研究

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原子与分子物理学报 2025年第6期42卷 43-50页

作者：靳帆赵志超运城学院应用化学系运城044000 运城学院科研产业部运城044000

基于第一性原理的多体格林函数理论方法,系统探究了锐钛矿TiO_(2)(001)表面负载Pt单原子催化剂的电子结构和光学性质,考虑Pt在完美表面和缺陷表面(O空位)两种基底上的负载.结果发现,Pt会在TiO_(2)禁带中间、价带和导带边缘引入新能级,... 详细信息

基于第一性原理的多体格林函数理论方法,系统探究了锐钛矿TiO_(2)(001)表面负载Pt单原子催化剂的电子结构和光学性质,考虑Pt在完美表面和缺陷表面(O空位)两种基底上的负载.结果发现,Pt会在TiO_(2)禁带中间、价带和导带边缘引入新能级,但不同基底负载的Pt单原子催化剂存在不同的带隙特性.Pt的负载会引起体系光学吸收红移,增大光学吸收范围,延伸光吸收至可见光甚至是红外区域,提升可见光活化的可能性,同时改善体系的激子束缚能,有利于空穴与电子有效分离,这可能是Pt负载后光催化性能提升的原因之一.然而,若在可见光或低能量紫外光激发后,分离的电子与空穴没有及时参与反应,体系衰变回最低激发态,此时极大的激子束缚能可能会加速电子与空穴重组,不利于表面催化反应的进行.负载在O空位的催化剂最低激发态的激子束缚能比完美表面小,重组速率慢.计算结果能够为理解单原子催化剂结构-性能关系提供一些见解.

关键词：二氧化钛 Pt单原子催化剂多体格林函数理论电子结构光吸收

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Induced transformation of antimony trioxide by Mn(II) oxidation and their co-transformed mechanism

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Journal of Environmental Sciences 2023年第7期129卷 69-78页

作者： You lv Caixiang Zhang chao Nan Zenghui fan Shuxin Huang State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science Wuhan 430074China

Antimony(Sb)is a toxic and carcinogenic element that often enters soil in the form of antimony trioxide(Sb_(2)O_(3))and coexists with manganese(Mn)in weakly alkaline *** oxides such as birnessite have been found to promote the oxidative dissolution of Sb_(2)O_(3),but few researches concerned the co-transformations of Sb_(2)O_(3) and Mn(II)in *** study investigated themutual effect of abiotic oxidation of Mn(II)and the coupled oxidative dissolution of Sb_(2)O_(3).The influencing factors,such as Mn(II)concentrations,pH and oxygen were also ***,their co-transformed mechanism was also explored based on the analysis of Mn(II)oxidation products with or without Sb_(2)O_(3) using XRD,SEM and *** results showed that the oxidative dissolution of Sb_(2)O_(3) was enhanced under higher pH and higher Mn(II)*** a lower Mn(II)concentration such as 0.01 mmol/L Mn(II)at pH 9.0,the improved dissolution of Sb_(2)O_(3) was attributed to the generation of dissolved intermediate Mn(III)species with strong oxidation ***,under higher Mn(II)concentrations,both amorphous Mn(III)oxides and intermediate Mn(III)species were responsible for promoting the oxidative dissolution of Sb_(2)O_(3).Most released Sb(∼72%)was immobilized by Mn oxides and Sb(V)was dominant in the adsorbed and dissolved total ***,the presence of Sb_(2)O_(3) not only inhibited the removal of Mn(II)by reducing Mn(III)to Mn(II)but also affected the final products of Mn *** example,amorphous Mn oxides were formed instead of crystalline Mn(III)oxides,such as ***,rhodochrosite(MnCO_(3))was formed with the high Mn(II)/Sb_(2)O_(3) ratio,but without being observed in the low Mn(II)/Sb_(2)O_(3) *** results of study could help provide more understanding about the fate of Sb in the environment and the redox transformation of Mn.

关键词： Antimony trioxide Mn(II)oxidation Oxidative dissolution Co-transformed mechanism

Ferrosilicon alloy granules prepared through centrifugal granulation process

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Journal of Iron and Steel Research International 2020年第11期27卷 1247-1258页

作者： Wen-chao He Xue-wei lv Zhi-ming Yan Gang-qiang fan Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China

A novel granulation process that involved the use of a rotary multi-nozzles cup atomizer and water cooling was proposed for ferroalloy *** effects of rotating speed and nozzle diameter on the properties of FeSi75 alloy(containing 75 wt.%Si)granules were *** indicated that median granule diameter decreased as rotating speed in creased,and initially increased and then decreased as nozzle diameter in *** optimal conditi ons for the gra nulation of FeSi75 alloy were a rotating speed of 150 r/min and nozzle diameter of 10 or 12 *** phase composition,micromorphology,and elemental distribution of the FeSi75 alloy granules were also studied by X-ray diffraction,scanning electron microscopy,and energy-dispersive X-ray *** order to provide guidance for the layout and water depth of the tank,the solidification behavior of ferrosilicon alloy droplet was numerically studied.A simplified model was established to elucidate the traveling trajectory and heat transfer of alloy droplet in air and cooling water during the atomization *** solidification time of droplet with different thicknesses of solidification layer increased with the in crease in alloy droplet diameter.

关键词： FeSi75 alloy Rotary multi-nozzles cup atomizer Size distribution Microstructural analysis Solidification behavior

控制方向未知的受限多智能体系统的预设时间模糊控制

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工程科学学报 2025年第1期47卷 121-129页

作者：李菲周超范利蓉王芳燕山大学理学院秦皇岛066004 河北农业大学海洋学院秦皇岛066003

综合考虑受控制方向未知、输入受限和状态时延影响的有领导者多智能体系统的编队控制问题,设计基于模糊逻辑系统的预设时间一致性控制策略.为了保证编队输出误差在预设时间内满足预定的约束范围要求,引入预设时间性能函数,构造Lyapunov-... 详细信息

综合考虑受控制方向未知、输入受限和状态时延影响的有领导者多智能体系统的编队控制问题,设计基于模糊逻辑系统的预设时间一致性控制策略.为了保证编队输出误差在预设时间内满足预定的约束范围要求,引入预设时间性能函数,构造Lyapunov-Krasovskii(L-K)泛函解决状态时延问题,将外界干扰和L-K泛函的导数中的部分项定义为未知非线性函数,并利用模糊逻辑系统对其进行估计,利用Nussbaum函数和均值定理分别处理控制方向未知和输入受限问题,基于以上设计,提出预设时间模糊控制策略,并通过Lyapunov稳定性理论,分析闭环系统的有界稳定性,数值对比仿真和两级化学反应器应用仿真说明控制方法的有效性.

关键词：多智能体系统状态时延输出误差约束输入受限控制方向未知

Enhancement and Application of Overset Grid Assembly

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Chinese Journal of Aeronautics 2010年第6期23卷 631-638页

作者： fan Jingjing Yan chao National Laboratory of Computational Fluid Dynamics Beijing University of Aeronautics and AstronauticsBeijing 100191China

In this article, the overset grid assembly method is improved to efficiently solve several critical problems that occur when applying overset grids to the complicated geometries and moving body. First, instead of using the two-step searching (i.e. cut and paste), a single-step searching method based on the grid cell size is proposed to modify holes and optimize the grid overlapping automatically. Second, discrepancies between the wall surface representations, where the grids overlap, are handled by introducing the wall's normal directions to the hole-map and projecting the interpolated points on the recipient mesh into the donor mesh. Finally, the dynamic overset method is modified to address the complex moving body problem. At every time step, the initial hole surface of the previous time step is dynamically adjusted to accomplish hole cutting and avoid the time consuming hole-map procedure. Numerical experiments show that the enhanced overset grid assembly method obtains satisfactory results.

关键词： overset grid hole-map hole-surface optimization surface grid overset dynamic overset

Thermophoresis effects on gas-particle phases flow behaviors in entrained flow coal gasifier using Eulerian model

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Chinese Journal of Chemical Engineering 2017年第6期25卷 712-721页

作者： chao Dai fan Gu School of Energy and Environment Southeast University Nanjing 210096 China

A numerical model based on the Eulerian–Eulerian two-fluid approach is used to simulate the gasification of coal char inside an entrained flow gasifier. In this model, effects of thermophoresis of coal char particles are thoroughly investigated. The thermophoresis is due to the gas temperature gradient caused by absorpted heat of coal char gasification. This work, firstly, calculates the gas temperature gradient and thermophoretic force at1100 °C,1200 °C,1300 °C and 1400 °C wall temperatures. Then, the changes of particle volume fraction and velocity in the gasifier are studied in the simulation with thermophoresis or not. The results indicate that considering the particle thermophoresis has some effects on the calculation of particle volume fraction in the gasifier, especially at wall temperature of 1400 °C, and the maximum particle volume fraction variance ratio reaches up to 1.38% on wall surface of the gasifier. These effects are mainly caused by large gas temperature gradient along the radial direction of the gasifier. For the particle velocity, the changes are small but can be observable along radial direction of the gasifier, which has good agreement with the distributions of radial gas temperature gradient and thermophoretic force. These changes above may have certain effects on gasification reaction rates in this Eulerian model. So the change of gasification reaction rates in the simulation with thermophoresis or not is studied finally.

关键词： Gasification Thermophoresis Eulerian model Two-phase flow