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61.
62.
研究了镍基高温合金GH202在800~1100 ℃高温氧化后晶粒、碳化物和强化相的演变过程。采用透射电子显微镜、扫描电子显微镜和电子背散射衍射对其微观结构进行了表征。结果表明:镍基高温合金的硬度随氧化温度的升高而降低,1100 ℃氧化100 h后,硬度降低了43.5%。800和900 ℃氧化后晶粒生长速度较慢,而经900 ℃氧化后晶界碳化物析出显著增加。在1000和1100 ℃氧化后,晶粒尺寸明显增大。氧化过程中晶界迁移是由晶界两侧自由能差决定,温度越高,晶界向曲率中心迁移越快,大量细小晶粒被吞并形成了大晶粒。大块状碳化物(MC)分解成大量的碳原子,与Cr原子结合形成少量的富Cr颗粒状M23C6。在900 ℃氧化150 h后,M23C6演化为富Ti的M6C。随着氧化温度的升高,碳化物在γ相中回熔。在800、900和1000 ℃氧化后,γ′相逐渐长大,在1100 ℃氧化100 h后,完全溶解于γ相。 相似文献
63.
通过共沉淀法制备了锌铝水滑石(ZnAl-LDH),采用XRD、FTIR、SEM对其结构进行了表征.将其配合用量为皮质量2%的铬粉(记为2%铬粉)应用于制革鞣制工艺中.考察了ZnAl-LDH制备时的金属源物质的量比、陈化时间对鞣制坯革收缩温度、鞣后废液中的Cr2O3质量浓度的影响.结果表明,ZnAl-LDH是尺寸在100~400 nm之间的片状材料.当n〔(Zn(NO3)2?6H2O)〕:n〔Al(NO3)3?9H2O〕=2.0:1.0,陈化时间为6 h时,制备的ZnAl-LDH-4具有优异的性能.与单独使用2%铬粉鞣制坯革相比,ZnAl-LDH-4(用量为皮质量的4%)配合2%铬粉鞣制坯革收缩温度由75℃提高到94℃,废液中的Cr2O3质量浓度由99.58 mg/L降低至46.98 mg/L,且加入ZnAl-LDH-4鞣制后,鞣后废液化学需氧量和生物需氧量均降低. 相似文献
64.
Yu-Ting Liu Xian-Bin Li Hui Zheng Nian-Ke Chen Xue-Peng Wang Xu-Lin Zhang Hong-Bo Sun Shengbai Zhang 《Advanced functional materials》2021,31(21):2009803
Phase change memory (PCM) is an emerging non-volatile data storage technology concerned by the semiconductor industry. To improve the performances, previous efforts have mainly focused on partially replacing or doping elements in the flagship Ge-Sb-Te (GST) alloy based on experimental “trial-and-error” methods. Here, the current largest scale PCM materials searching is reported, starting with 124 515 candidate materials, using a rational high-throughput screening strategy consisting of criteria related to PCM characteristics. In the results, there are 158 candidates screened for PCM materials, of which ≈68% are not employed. By further analyses, including cohesive energy, bond angle analyses, and Born effective charge, there are 52 materials with properties similar to the GST system, including Ge2Bi2Te5, GeAs4Te7, GeAs2Te4, so on and other candidates that have not been reported, such as TlBiTe2, TlSbTe2, CdPb3Se4, etc. Compared with GST, materials with close cohesive energy include AgBiTe2, TlSbTe2, As2Te3, TlBiTe2, etc., indicating possible low power consumption. Through further melt-quenching molecular dynamic calculation and structural/electronic analyses, Ge2Bi2Te5, CdPb3Se4, MnBi2Te4, and TlBiTe2 are found suitable for optical/electrical PCM applications, which further verifies the effectiveness of this strategy. The present study will accelerate the exploration and development of advanced PCM materials for current and future big-data applications. 相似文献
65.
Jinming Wang Meng Yang Guodong Zou Di Liu Qiuming Peng 《Advanced functional materials》2021,31(21):2101180
Lithium (Li) metal, as an appealing candidate for the next-generation of high-energy-density batteries, is plagued by its safety issue mainly caused by uncontrolled dendrite growth and infinite volume expansion. Developing new materials that can improve the performance of Li-metal anode is one of the urgent tasks. Herein, a new MXene derivative containing pure rutile TiO2 and N-doped carbon prepared by heat-treating MXene under a mixing gas, exhibiting high chemical activity in molten Li, is reported. The lithiation MXene derivative with a hybrid of LiTiO2-Li3N-C and Li offers outstanding electrochemical properties. The symmetrical cell assembling lithiation MXene derivative hybrid anode exhibits an ultra-long cycle lifespan of 2000 h with an overpotential of ≈30 mV at 1 mA cm−2, which overwhelms Li-based anodes reported so far. Additionally, long-term operations of 34, 350, and 500 h at 10 mA cm−2 can be achieved in symmetrical cells at temperatures of −10, 25, and 50 °C, respectively. Both experimental tests and density functional theory calculations confirm that the LiTiO2-Li3N-C skeleton serves as a promising host for Li infusion by alleviating volume variation. Simultaneously, the superlithiophilic interphase of Li3N guides Li deposition along the LiTiO2-Li3N-C skeleton to avoid dendrite growth. 相似文献
66.
Jia Dai Xiang Cheng Xiaofeng Li Zhisheng Wang Yufeng Wang Jing Zheng Jun Liu Jiawei Chen Changjin Wu Jinyao Tang 《Advanced functional materials》2021,31(48):2106204
Synthetic active matters are perfect model systems for non-equilibrium thermodynamics and of great potential for novel biomedical and environmental applications. However, most applications are limited by the complicated and low-yield preparation, while a scalable synthesis for highly functional microswimmers is highly desired. In this paper, an all-solution synthesis method is developed where the gold-loaded titania-silica nanotree can be produced as a multi-functional self-propulsion microswimmer. By applying light, heat, and electric field, the Janus nanotree demonstrated multi-mode self-propulsion, including photochemical self-electrophoresis by UV and visible light radiation, thermophoresis by near-infrared light radiation, and induced-charge electrophoresis under AC electric field. Due to the scalable synthesis, the Janus nanotree is further demonstrated as a high-efficiency, low-cost, active adsorbent for water decontamination, where the toxic mercury ions can be reclaimed with enhanced efficiency. 相似文献
67.
教学行为分析作是教学质量分析的重要组成部分,也是教学引导与反馈机制的重要依据。文章阐述了人工智能(AI)的含义及发展历程,重点分析总结了教学行为分析方法及AI在教学行为分析上的应用。文章以东南大学电工电子在线实验为研究平台,探索分析了AI技术在实验教学行为分析上的可行性,梳理了基于专家系统的在线实验分析系统的设计思路,充分探讨了“智能”教育在实验教学中的深刻内涵。 相似文献
68.
Peiying Wang Juanli Zhao Yun Fan Wei Zhang Yuanyuan Cui Liangmiao Zhang Bin Liu Hongqiang Nian Yiran Li 《Ceramics International》2021,47(11):15023-15029
In this work, the composition-dependent point defect types and formation energies of RE2Hf2O7 (RE = La, Ce, Pr, Nd, Pm, Sm, Eu and Gd) as well as the oxygen diffusion behavior are systematically investigated by first-principles calculations. The possible defect reactions and dominant defect complexes under stoichiometric and non-stoichiometric conditions are revealed. It is found that O Frenkel pairs are the predominant defect in stoichiometric pyrochlore hafnates. Hf-RE cation anti-site defects, accompanied by RE vacancies and/or oxygen interstitials, are stable in the non-stoichiometric case of HfO2 excess. On the other hand, RE-Hf anti-site defects together with oxygen vacancies and/or RE interstitials are preferable in the case of RE2O3 excess. The energy barriers for the migration along the VO48f - VO48f pathway of pyrochlore hafnates were calculated to be between 0.81 eV and 0.89 eV. Based on these results, a defect engineering strategy is proposed and the pyrochlore hafnates investigated here are predicted to exhibit potential oxygen ionic conductivity. 相似文献
69.
Cheng-Chin Huang Ching-Yao Yang Chin-Chuan Su Kai-Min Fang Cheng-Chieh Yen Ching-Ting Lin Jui-Min Liu Kuan-I Lee Ya-Wen Chen Shing-Hwa Liu Chun-Fa Huang 《International journal of molecular sciences》2021,22(9)
4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), a major active metabolite of bisphenol A (BPA), is generated in the mammalian liver. Some studies have suggested that MBP exerts greater toxicity than BPA. However, the mechanism underlying MBP-induced pancreatic β-cell cytotoxicity remains largely unclear. This study demonstrated the cytotoxicity of MBP in pancreatic β-cells and elucidated the cellular mechanism involved in MBP-induced β-cell death. Our results showed that MBP exposure significantly reduced cell viability, caused insulin secretion dysfunction, and induced apoptotic events including increased caspase-3 activity and the expression of active forms of caspase-3/-7/-9 and PARP protein. In addition, MBP triggered endoplasmic reticulum (ER) stress, as indicated by the upregulation of GRP 78, CHOP, and cleaved caspase-12 proteins. Pretreatment with 4-phenylbutyric acid (4-PBA; a pharmacological inhibitor of ER stress) markedly reversed MBP-induced ER stress and apoptosis-related signals. Furthermore, exposure to MBP significantly induced the protein phosphorylation of JNK and AMP-activated protein kinase (AMPK)α. Pretreatment of β-cells with pharmacological inhibitors for JNK (SP600125) and AMPK (compound C), respectively, effectively abrogated the MBP-induced apoptosis-related signals. Both JNK and AMPK inhibitors also suppressed the MBP-induced activation of JNK and AMPKα and of each other. In conclusion, these findings suggest that MBP exposure exerts cytotoxicity on β-cells via the interdependent activation of JNK and AMPKα, which regulates the downstream apoptotic signaling pathway. 相似文献
70.
Khalid Mohamed Ali Zhao Yue Yang Yuxiang Liu Xiangnong Garrone Eufrosina Dai Anbang Diao Guangxiang Carlini Riccardo 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(8):3324-3333
Journal of Inorganic and Organometallic Polymers and Materials - Due to their excellent properties, polymides (PIs) result promising as high-performance materials in different technological fields.... 相似文献