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Novel C_(sf)/SiBCN composites prepared by densifying C_(sf)/MA-SiBCN with the PIP process:Oxidation behavior and damage mechanism

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Journal of Advanced Ceramics 2024年第5期13卷 666-678页

作者： Wenhao Dou Daxin Li Bingzhu Wang Zhihua Yang jun chen Dechang Jia Ralf Riedel Yu Zhou Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structural-Functional Integration Materials and Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Chongqing Research Institute of HIT Chongqing 401135China Beijing Institute of Control Engineering Beijing 100094China Institut für Materialwissenschaft Technische Universität DarmstadtDarmstadt D-64287Germany School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

To improve the oxidation resistance of short carbon fiber(C_(sf))-reinforced mechanically alloyed SiBCN(MA-SiBCN)(C_(sf)/MA-SiBCN)composites,dense amorphous C_(sf)/SiBCN composites containing both MA-SiBCN and polymer-derived ceramics SiBCN(PDCs-SiBCN)were prepared by repeated polymer infiltration and pyrolysis(PIP)of layered C_(sf)/MA-SiBCN composites at 1100℃,and the oxidation behavior and damage mechanism of the as-prepared C_(sf)/SiBCN at 1300–1600℃ were compared and discussed with those of C_(sf)/*** C_(sf)/MA-SiBCN composites resist oxidation attack up to 1400℃ but fail at 1500℃ due to the collapse of the porous framework,while the PIP-densified C_(sf)/SiBCN composites are resistant to static air up to 1600℃.During oxidation,oxygen diffuses through preexisting pores and the pores left by oxidation of carbon fibers and pyrolytic carbon(PyC)to the interior of the *** to the oxidative coupling effect of the MA-SiBCN and PDCs-SiBCN matrices,a relatively continuous and dense oxide layer is formed on the sample surface,and the interfacial region between the oxide layer and the matrix of the as-prepared composite contains an amorphous glassy structure mainly consisting of Si and O and an incompletely oxidized but partially crystallized matrix,which is primarily responsible for improving the oxidation resistance.

关键词： mechanically alloyed SiBCN(MA-SiBCN) polymer-derived ceramics SiBCN(PDCs-SiBCN) short carbon fiber-reinforced SiBCN(C_(sf)/SiBCN)composites polymer infiltration and pyrolysis(PIP) oxidation damage mechanism

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Sliding tribological characteristics of Ti48Zr20Nb12Cu5Be15 metallic glass matrix composites under different conditions

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Journal of Iron and Steel Research International 2018年第3期25卷 282-290页

作者： Zhong-kun Bai Li-ming Du Ming chen Min Zhang Xiao-hui Shi Hui-jun Yang College of Materials Science and Engineering TaiyuanUniversity of Technology Taiyuan 030024 Shanxi China

A systematic research on the tribological characteristics of Ti48Zr20Nb12Cu5Be15 metallic glass matrix composites was performed under different normal loads in dry condition and simulated seawater. The wear rate decreased with the increase in normal load under dry and simulated seawater conditions. The friction coefficient was lower in the dry condition than in the simulated seawater. The composite showed better wear resistance at lower loads （3, 5 and 10 N） hut poor wear resistance at higher loads （15 and 17 N） in the simulated seawater. The analysis of the worn surface illustrated that the wear mechanism in dry condition was plastic deformation, adhesive wear and abrasive wear at 3 and 5 N, while it was abrasive wear and adhesive wear at 10, 15 and 17 N. The wear mechanism in simulated seawater was abrasive wear, plastic deformation and adhesive wear at 3 N, adhesive wear at 10 N, and abrasive wear at 5, 15 and 17 N. At the same time, the corrosion occurred during wear tests in the simulated seawater.

关键词： Amorphous material Rapid solidification Friction Wear Corrosion

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NRF1-mediated microglial activation triggers high-altitude cerebral edema

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Journal of Molecular Cell Biology 2022年第5期14卷 43-56页

作者： xueting Wang Guijuan chen Baolan Wan Zhangji Dong Yan xue Qianqian Luo Dan Wang Yapeng Lu Li Zhu Institute of Special Environmental Medicine Nantong UniversityNantong 226019China Co-nnovation Center of Neuroregeneration iangsu Key Laboratory of NeuroregenerationNantong UniversityNantong 226019China Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education Nantong UniversityNantong 226019China

High-altitude cerebral edema(HACE)is a potentially fatal encephalopathy associated with a time-dependent exposure to the hypobaric hypoxia of *** formation of HACE is affected by both vasogenic and cytotoxic *** over-activated microglia potentiate the damage of blood-brain barrier(BBB)and exacerbate cytotoxic *** light with the activation of microglia in HACE,we aimed to investigate whether the over-activated microglia were the key turning point of acute mountain sickness to *** in vivo experiments,by exposing mice to hypobaric hypoxia(7000 m above sea level)to induce HACE model,we found that microglia were activated and migrated to blood *** depletion by PLX5622 obviously relieved brain *** in vitro experiments,we found that hypoxia induced cultured microglial activation,leading to the destruction of endothelial tight junction and astrocyte ***-regulated nuclear respiratory factor 1(NRF1)accelerated pro-inflammatory factors through transcriptional regulation on nuclearfactorkappa B p65(NF-kB p65)and mitochondrial transcription factorA(TFAM)in activated microglia under ***1 also up-regulated phagocytosis by transcriptional regulation on caveolin-1(CAV-1)and adaptorrelated protein complex 2 subunit beta(AP2B1).The present study reveals a new mechanism in HACE:hypoxia over-activates microglia through up-regulation of NRF1,which both induces inflammatory response through transcriptionally activating NF-kB p65 and TFAM,and enhances phagocytic function through up-regulation of CAV-1 and AP2B1;hypoxia-activatedmicroglia destroy the integrity of BBB and release pro-inflammatory factors that eventually induce HACE.

关键词： high-altitude cerebral edema hypoxia microglia inflammation nuclear respiratory factor 1 endocytosis

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Improved photovoltaic performance of dye-sensitized solar cells by carbon-ion implantation of tri-layer titania film electrodes

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Rare Metals 2015年第1期34卷 34-39页

作者： jun Luo Wei-Guang Yang Bin Liao Hai-Bo Guo Wei-Min Shi Yi-Gang chen School of Materials Science and Engineering Shanghai University College of Nuclear Science and Technology Beijing Normal University

TiO2 tri-layer structure films were modified by C-ions implantation for improving the photovoltaic perfor- mance of dye-sensitized solar cells （DSSCs）, in which the structure of TiOa changes from rutile to anatase and the sizes of TiOa particles increase. The optimal concentration of ions implantation for C-implanted cells is 1 ~ 1015 ***-2, and the maximum conversion efficiency of 5.32 % is achieved （luminous intensity of 1 sun, light irradiance of ***）, which is 25.2 % higher than that of unimplanted cell. The significant improvement in conversion efficiency by carbon- ion implantation is contributed to reducing charge recombi- nation and enhancing the light-harvesting ability, as indicated from incident photon-to-collected electron conversion effi- ciency （IPCE） and ultraviolet-visible （UV-Vis） measure- ments. Furthermore, the charge carrier＇s lifetime in the tri- layer titania films is prolonged after carbon-ion implantations.

关键词： Dye-sensitized solar cell Ion implantation Carbon Conversion efficiency Charge transfer

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Metal-organic framework derived CoSe2 nanoparticles anchored on carbon fibers as bifunctional electrocatalysts for efficient overall water splitting

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Nano Research 2016年第8期9卷 2234-2243页

作者： chencheng Sun Qiuchun Dong jun Yang Ziyang Dai Jianjian Lin Peng chen Wei Huang Xiaochen Dong Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University (NanfingTech) 30 South Puzhu Road Nanjing 211816 China School of Chemical and Biomedical Engineering Nanyang Technological University 62 Nanyang Drive 637459 Singapore Singapore

The development of efficient, low-cost, for water splitting, particularly those stable, non-noble-metal electrocatalysts that can catalyze both the hydrogen evolution reaction （HER） at the cathode and oxygen evolution reaction （OER） at the anode, is a challenge. We have developed a facile method for synthesizing CoSe2 nanoparticles uniformly anchored on carbon fiber paper （CoSe2/CF） via pyrolysis and selenization of in situ grown zeolitic imidazolate framework-67 （ZIF-67）. CoSe2/CF shows high and stable catalytic activity in both the HER and OER in alkaline solution. At a low cell potential, i.e., 1.63 V, a water electrolyzer equipped with two CoSe2/CF electrodes gave a water-splitting current of 10 ***-2. At a current of 20 mA-cm-2, it can operate without degradation for 30 h. This study not only offers a cost-effective solution for water splitting but also provides a new strategy for developing various catalytic nanostructures by changing the metal-organic framework precursors.

关键词： metal-organic framework cobalt selenide electrocatalyst overall water splitting

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Composition and phase structure dependence of mechanical and magnetic properties for AlCoCuFeNi_x high entropy alloys

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Journal of Materials Science & Technology 2019年第6期35卷 1175-1183页

作者： Cong Liu Wenyi Peng C.S. Jiang Hongmin Guo jun Tao Xiaohua Deng Zhaoxia chen School of Materials Science and Engineering Nanchang University Nanchang 330031 China Institute of Space Science and Technology. Nanchang University Nanchang 330031 China

In this study, the effects of composition and phase constitution on the mechanical properties and magnetic performance of AlCoCuFeNix(x = 0.5, 0.8, 1.0, 1.5, 2.0, 3.0 in molar ratio) high entropy alloys(HEAs)were investigated. The results show that Ni element could lead to the evolution from face centered cubic(FCC), body centered cubic(BCC) and ordered BCC coexisting phase structure to a single FCC phase. The change of phase constitution enhances the plasticity but reduces the hardness and strength. One of the interesting points is the excellent soft magnetic properties of AlCoCuFeNixHEAs. Soft magnetic performance is dependent on composition and phase transition. AlCoCuFeNi1.5 alloy, achieving a better balance of mechanical and magnetic properties, could be applied as structure materials and soft magnetic materials(SMMs). High Curie temperature(>900 K) and strong phase stability below 1350 K of AlCoCuFeNi0.5 alloy confirm its practicability in a high-temperature environment. Atomic size difference(δ) is utilized as the critical parameter to explain the lattice strain and phase transformation induced by Ni addition.

关键词： High entropy alloy Phase transformation Mechanical property Soft magnetic performance Atomic size difference

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Observation of Interference Effects in (e, 2e) Electron Momentum Spectroscopy of SF6

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Chinese Journal of Chemical Physics 2015年第5期28卷 -页

作者： Min-fu Zhao Xu Shan Jing Yang En-liang Wang Shan-shan Niu Xiang-jun chen Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics University of Science and Technology of China Hefei 230026 ChinaThe Center of Basic Laboratory West Anhui University Lu'an 237012 China Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics University of Science and Technology of China Hefei 230026 China

Two-dimensional electron density map (2D map) of binding energy and relative azimuthal angle (i.e., momentum) for the outer-valence molecular orbitals of SF6 has been measured by a highly sensitive electron momentum spectrometer with noncoplanar symmetric geometry at the impact energy of 1.2 keV plus binding energy. The experimental electron momentum profiles for the relevant molecular orbitals have been extracted from the 2D map and interpreted on the basis of the quantitative calculations using the density functional theory with B3LYP hybrid functional. For the outermost F2p nonbonding orbitals of SF6, the interference patterns are clearly observed in the ratios of the electron momentum profiles of molecular orbitals to that of atomic F2p orbital.

关键词： (e,2e) electron momentum spectroscopy Interference effect Bond oscillation Electron momentum profile

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Acupuncture promotes functional recovery after cerebral hemorrhage by upregulating neurotrophic factor expression

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Neural Regeneration Research 2020年第8期15卷 1510-1517页

作者： Dan Li Qiu-Xin chen Wei Zou Xiao-Wei Sun xue-Ping Yu Xiao-Hong Dai Wei Teng Third Department of Acupuncture First Affiliated HospitalHeilongjiang University of Chinese MedicineHarbinHeilongjiang ProvinceChina Department of Acupuncture Third Affiliated HospitalBeijing University of Chinese MedicineBeijingChina

Acupuncture is widely used in the treatment of cerebral hemorrhage,and it improves outcomes in experimental animal models and ***,the mechanisms underlying the effectiveness of acupuncture treatment for cerebral hemorrhage are still *** this study,a model of intracerebral hemorrhage was produced by injecting 50μL autologous blood into the caudate nucleus in Wistar *** at Baihui(DU20)and Qubin(GB7)acupoints was performed at a depth of 1.0 inch,12 hours after blood injection,once every 24 *** needle was rotated at 200 r/min for 5 minutes,For each 30-minute session,needling at 200 r/min was performed for three sessions,each lasting 5 *** the positive control group,at 6 hours,and 1,2,3 and 7 days after induction of hemorrhage,the rats were intraperitoneally injected with 1 mL aniracetam(0.75 mg/mL),three times a *** Bederson behavioral test was used to assess palsy in the contralateral *** blot assay was used to examine the expression levels of Nestin and basic fibroblast growth factor in the basal *** was performed to count the number of Nestin-and glial cell line-derived neurotrophic factor-positive cells in the basal *** effectively reduced hemorrhage and brain edema,elevated the expression levels of Nestin and basic fibroblast growth factor in the basal ganglia,and increased the number of Nestin-and glial cell line-derived neurotrophic factor-positive cells in the basal ***,these findings suggest that acupuncture promotes functional recovery after cerebral hemorrhage by increasing the expression of neurotrophic *** study was approved by the Committee for Experimental Animals of Heilongjiang Medical Laboratory Animal Center(approval No.2017061001)on june 10,2017.

关键词： acupuncture basic fibroblast growth factor brain cell protection cerebral hemorrhage electron microscope glial cell line-derived neurotrophic factor immunohistochemistry Nestin western blot assay

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Ultrasensitive and accurate diagnosis of urothelial cancer by plasmonic AuNRs-enhanced fluorescence of near-infrared Ag_(2)S quantum dots

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Rare Metals 2022年第11期41卷 3828-3838页

作者： Dong Zhang Cai-Ping Ding Xiao-Yue Zheng Jia-Zhou Ye Zi-Hai chen Jian-Hua Li Ze-jun Yan jun-Hui Jiang You-Ju Huang Department of Urology&Nephrology Ningbo First HospitalThe Affiliated Hospital of Zhejiang UniversityNingbo315000China College of Material Chemistry and Chemical EngineeringKey Laboratory of Organosilicon Chemistry and Material TechnologyMinistry of EducationHangzhou Normal UniversityHangzhou311121China Anhui Shenghaitang Traditional Chinese Medicine Decoction Pieces Co. LtdBozhou236800China Anhui Topway Testing Services Co. Ltd.Xuancheng Economic and Technological Development ZoneXuancheng242000China

Urothelial carcinoma(UC)is a common malignant tumor in the urinary system with high recurrence rate and low survival rate 5 years after *** present,imaging examination and other diagnostic methods have some shortcomings such as invasiveness and ***,it is urgent to develop a simple,rapid,noninvasive,highly sensitive and highly specific strategy to diagnose ***,a high-performance fluorescence sensor was constructed by the plasmonic gold nanorods(AuNRs)-enhanced near-infrared(NIR)fluorescence of silver sulfide quantum dots(Ag_(2)S QDs).The designed sensor can be used for the fast and accurate detection of small molecule single-transmembrane protein(FXYD3),which is overexpressed in 90%of ureteral cancers and 84%of high-grade bladder *** to its high specificity,the NIR fluorescence sensor achieves the detection of FXYD3 in the range of 0.25-150 ng·ml^(-1)with a detection limit of 0.2 ng·ml^(-1).Importantly,it also can be used for accurate diagnosis of FXYD3 in the urine of patients with relevant cancers,and the results are consistent with clinical cystoscopy and pathological *** proposed fluorescence sensor provides a simple,ultrasensitive,reliable method for UC screening,tumor-grade classification and postoperative monitoring and will have great potential for clinical applications.

关键词： Urothelial carcinoma FXYD3 Plasmonic enhanced fluorescence Ultrasensitive Accurate diagnosis

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Morphology of α-Si_3N_4 in Fe–Si_3N_4 prepared via flash combustion

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International Journal of Minerals,Metallurgy and Materials 2015年第12期22卷 1322-1327页

作者： Bin Li jun-hong chen Jin-dong Su Ming-wei Yan Jia-lin Sun Yong Li School of Materials Science and Engineering University of Science and Technology Beijing

The state and formation mechanism of α-Si3N4 in Fe-Si3N4 prepared by flash combustion were investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicate that α-SiaN4 crystals exist only in the Fe-Si3N4 dense areas. When FeSi75 particles react with N2, which generates substantial heat, a large number of Si solid particles evaporate. The product between Si gas and N2 is a mixture of α-Si3N4 and β-Si3N4. At the later stage of the flash combustion process, α-Si3N4 crystals dissolve and reprecipitate as α-Si3N4 and the β-Si3N4 crystals grow outward from the dense areas in the product pool. As the temperature decreases, the α-SiaN4 crystals cool before transforming into β-SiaN4 crystals in the dense areas of Fe-Si3N4. The phase composition of flash-combustion-synthesized Fe-SiaN4 is controllable through manipulation of the gas-phase reaction in the early stage and the α→β transformation in the later stage.

关键词： silicon nitride combustion synthesis morphology crystal growth

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