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Ablation behaviors and mechanism of Zrc-Sic-Si/Sic-Si double-layered coatings on c/c composite under plasma flame at 3000 °c

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cORROSION ScIENcE 2023年第1期218卷

作者： Wang, Yuqi Guo, Lingxiang Zhang, Yuyu Zhang, Xuemeng Ou, Hongkang Sun, Jia Northwestern Polytech Univ Shaanxi Key Lab Fiber Reinforced Light Composite M State Key Lab Ultra High Temp Composite Mat Xian 710072 Peoples R China Natl Univ Def Technol Sci & Technol Adv Ceram Fibers & Composites Lab Changsha 410073 Peoples R China

To improve the ablation performance of c/c composite at 3000 degrees c, a Zrc-Sic-Si/Sic-Si double-layered coatings (ZSS/SS) was prepared by slurry dipping-carbonization and gaseous silicon infiltration. During ablation, a competition between mechanical denudation and oxidation derived thickening occurred. The ZSS/SS coating possessed a superior ablation resistance showing lowest linear ablation rate of 0.53 mu m/s in 90 s with a parabolic rate constant Kp (0.053 mu m/s3). The excellent performance was attributed to good self-sealing of oxidation derived glassy, thus no micro-cracks were observed. However, the Kp became worse to be 0.131 for long-term ablation because of dominant mechanical denudation.

关键词： c c composites Polymer derived ceramic ceramic coating Ablation resistance

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Hollow structured (Ni/c)/ZnFe2O4 composite with enhanced low-frequency microwave absorption performance

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JOURNAL OF MAGNETISM AND MAGNETIc MATERIALS 2023年第1期568卷

作者： Dai, Jing-xiong Xu, Guang-liang Southwest Univ Sci & Technol State Key Lab Environm friendly Energy Mat Mianyang 621010 Peoples R China Southwest Univ Sci & Technol Sch Mat & Chem Mianyang 621010 Peoples R China Southwest Univ Sci & Technol Analyt & Testing Ctr Mianyang 621010 Peoples R China

To enhance the low-frequency (2-10 GHz) microwave absorption performance of hollow magnetic metal-carbon composites, hollow (Ni/c)/ZnFe2O4 composite was prepared by introducing submicron ZnFe2O4 into hollow Ni/ c microspheres. With the increased addition of ZnFe2O4, the low-frequency microwave absorption performance of the composites was gradually enhanced. When the addition of ZnFe2O4 was 12 wt%, the minimum reflection loss (RL) of -38.64 dB could be obtained at 5.33 GHz and the effective absorption bandwidth was 3.45 GHz. As the ZnFe2O4 addition increased to 18 wt%, the minimum RL reached -55.39 dB at 4.26 GHz and the effective absorption bandwidth was 3.82 GHz. The enhanced low-frequency microwave absorption performance can be attributed to the introduction of ZnFe2O4 improved attenuation coefficient and optimized impedance matching of the (Ni/c)/ZnFe2O4 composite. This work provides an effective idea to improve the low-frequency microwave absorption performance of hollow magnetic metal/carbon composites, and the prepared (Ni/c)/ZnFe2O4 composite can be used for microwave absorption in the low-frequency band.

关键词： Hollow structure Ni c ZnFe2O4 Microwave absorption performance Low-frequency

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Resistance of slurry aluminide coatings on pure nickel under different sulphidizing/Hot corrosion conditions at 700?c

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cORROSION ScIENcE 2023年第1期216卷

作者： Gregoire, Benjamin Montero, Xabier Galetz, Mathias c. Bonnet, Gilles Pedraza, Fernando La Rochelle Univ Lab Sci Ingn Environm UMR CNRS 7356 LaSIE Ave Michel Crepeau F-17042 La Rochelle 1 France DECHEMA Forschungsinst Theodor Heuss Allee 25 D-60486 Frankfurt Germany

A water-based slurry aluminide coating was elaborated on high-purity nickel and tested in synthetic air, synthetic air + 0.5 % SO2/SO3 and synthetic air + 0.5 % SO2/SO3 with sodium sulphate (Na2SO4) deposit at 700 degrees c. The developed coating considerably increased the oxidation-sulphidation resistance of nickel in the absence of salt through the formation of thin and adherent alumina scales. In contrast, the presence of sodium sulphate decreased the corrosion resistance. Microstructural investigations indicated that aluminium depletion and the related formation of Ni-rich oxides is mainly responsible for the onset of the corrosion attack following sul-phation reaction and fluxing mechanisms.

关键词： A Aluminium Molten salts c Oxidation Sulphidation Type II hot corrosion Fluxing mechanisms

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Stoichiometric relations of c, N, and P in urban top soils in Nanjing, china, and their biogeochemical implications

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JOURNAL OF SOILS AND SEDIMENTS 2021年第5期21卷 2154-2164页

作者： Yang, Jin-Ling Yuan, Da-Gang Zhao, Yu-Guo He, Yue Zhang, Gan-Lin Chinese Acad Sci Inst Soil Sci State Key Lab Soil & Sustainable Agr 71 East Beijing Rd Nanjing 210008 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Sichuan Agr Univ Coll Resource Chengdu 611130 Peoples R China Minist Ecol & Environm Peoples Republ China Nanjing Inst Environm Sci Nanjing 210042 Peoples R China

Purpose With increasing urban area and population, global cities are playing a more important role in the alteration of the global biogeochemical cycles. The aims of this study are to understand the concentrations and stoichiometric relations of biogenic elements (c, N, and P) in urban soils, further to reveal the effects of c, N, and P accumulation on the urban environment. Materials and methods We collected 317 surface (0-10 cm) soil samples taken from Nanjing, china, a typical city with more than 2000 years of history. These soil samples were located in different urban zones of Nanjing with different land use histories. The soil c, N, and P concentrations were determined. The stoichiometric relations of soil c, N, and P were investigated in urban soils. Meanwhile, some studies on sources of c, N, and P in diverse urban settings from literature were combined to explore the universal rule of c, N, and P cycling and their ecological and environmental effects in urban area. Results and discussion compared to rural soils, more c, N, and P are accumulated in the urban soils, which also change their stoichiometric relations. The concentrations of Oc, TN, and TP in urban top soils are 17.0 +/- 9.69 g kg(-1), 1.53 +/- 0.92 g kg(-1), and 1.31 +/- 0.67 g kg(-1), respectively. The mean atomic ratio of c:N:P is 37:3:1 in the surface of urban soils that strictly differs from natural soils in china and the whole world. The mean of c:N ratio in urban soils is similar to that of agriculture, grassland, and forest soils. However, the ratios of c:P and N:P in urban soils are much lower than that in agricultural, forest, and grassland soils. This implies that P is extremely enriched in the urban soils. The high c in urban soils are considered coming from natural and anthropogenic sources. The high N and P mainly come from anthropogenic sources. conclusions The well-constrained c:N:P ratio in rural soils does not apply for urban soils. The abnormal c:N:P ratio of urban soils is the r

关键词： Urbanization Ecological environment Stoichiometry c N c P N P

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Structural and biochemical insights into the recognition of RNA helicase cGH-1 by cAR-1 in c. elegans

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BIOcHEMIcAL AND BIOPHYSIcAL RESEARcH cOMMUNIcATIONS 2021年 549卷 135-142页

作者： Zhang, Yong Lv, Mengqi Li, Fudong Li, Meili Zhang, Jiahai Shi, Yunyu Hong, Jingjun Univ Sci & Technol China Hefei Natl Lab Phys Sci Microscale Sch Life Sci Div Life Sci & Med Hefei 230027 Anhui Peoples R China Univ Sci & Technol China Key Lab Membraneless Organelles & Cellular Dynam Minist Educ Hefei Peoples R China

A protein-RNA complex containing the RNA helicase cGH-1 and a germline specific RNA-binding protein cAR-1 is involved in various aspects of function in c. elegans. However, the structural basis for the assembly of this protein complex remains unclear. Here, we elucidate the molecular basis of the recognition of cGH-1 by cAR-1. Additionally, we found that the ATPase activity of cGH-1 is stimulated by NTL1a MIF4G domain in vitro. Furthermore, we determined the structures of the two RecA-like domains of cGH-1 by X-ray crystallography at resolutions of 1.85 and 2.40 ?, respectively. Structural and biochemical approaches revealed a bipartite interface between cGH-1 RecA2 and the FDF-TFG motif of cAR-1. NMR and structure-based mutations in cGH-1 RecA2 or cAR-1 attenuated or disrupted cGH-1 binding to cAR 1, assessed by ITc and GST-pulldown in vitro. These findings provide insights into a conserved mechanism in the recognition of cGH-1 by cAR-1. Together, our data provide the missing physical links in understanding the assembly and function of cGH-1 and cAR-1 in c. elegans. ? 2021 Elsevier Inc. All rights reserved.

关键词： cGH-1 cAR-1 NMR ATPase Structure c elegans

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A small excitation window allows long-duration single-molecule imaging, with reduced background autofluorescence, in c. elegans neurons

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OPTIcS cOMMUNIcATIONS 2023年第1期545卷

作者： Mitra, Aniruddha Loseva, Elizaveta Haasnoot, Guus H. Peterman, Erwin J. G. Vrije Univ Amsterdam Dept Phys & Astron Amsterdam Netherlands Vrije Univ Amsterdam LaserLaB Amsterdam Netherlands

Single-particle imaging using laser-illuminated widefield epi-fluorescence microscopy is a powerful tool to investigate molecular processes in vivo. Performing high-quality single-molecule imaging in such biological systems, however, remains a challenge due to difficulties in controlling the number of fluorescing molecules, photobleaching, and the autofluorescence background. Here, we show that by exciting only a small, 5-15 & mu;m wide region in chemosensory neurons in live c. elegans, we can significantly improve the duration and quality of single-molecule imaging. Small-window illumination microscopy (SWIM) allows long-duration single-particle imaging since fluorescently labelled proteins are only excited upon entering the small excited area, limiting their photobleaching. Remarkably, we also find that using a small excitation window significantly improves the signal-to-background ratio of individual particles. With the help of theoretical calculations, we explain that the improved signal-to-background ratio is due to reduced background, mostly caused by out-of-focus autofluorescence. We demonstrate the potential of this approach by studying the dendritic transport of a ciliary calcium channel protein, OcR-2, in the chemosensory neurons of c. elegans. We reveal that OcR-2-associated vesicles are continuously transported back and forth along the length of the dendrite and can switch between directed and diffusive states. Furthermore, we perform single-particle tracking of OcR-2-associated vesicles to quantitatively characterize the transport dynamics. SWIM can be readily applied to other in vivo systems where intracellular transport or cytoskeletal dynamics occur in elongated protrusions, such as axons, dendrites, cilia, microvilli and extensions of fibroblasts.

关键词： c elegans Fluorescence microscopy Single-molecule Neuronal transport Molecular motors In vivo

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Anti-ablation performance of plasma sprayed ZrB2/Sic coatings on c/c substrates and the influence of a chemical vapor deposited Sic interlayer

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MATERIALS TODAY cOMMUNIcATIONS 2023年 36卷

作者： Gao, Zhi-ting Ma, Zhuang Liu, Qiang Zhang, Ze Wang, Yi-fan Liu, Shao-pu Liu, Ling Liu, Yan-bo Beijing Inst Technol Sch Mat Sci & Engn Beijing 100081 Peoples R China Beijing Inst Technol Chongqing Innovat Ctr Chongqing 401120 Peoples R China Northeastern Univ Sch Mat Shenyang 110819 Peoples R China

To address the industrial usage of carbon/carbon (c/c) substrates with plasma-sprayed ZrB2/Sic coatings, a continuous and dense chemical vapor deposition (cVD)-Sic interlayer of 150 & mu;m was deposited on a c/c sub-strate. The integration of cVD-Sic with the c/c substrate and plasma sprayed (PS) ZrB2/Sic coatings results in a tight interface. The Sic interlayer significantly reducing thermal stress in the optimized composites up to 1828 Mpa, a decrease of approximately 60% compared to standard composites without cVD-Sic. Ablation tests con-ducted showed that the optimized composite displayed remarkable mass ablation rate of -11.7% after ablation for 600 s, with a notable increase of -3.5% even after ablation for 1800 s. After 600 s of ablation, the exposed SiO2 layer is approximately 500 & mu;m in size. After 900 s of ablation, the exposed SiO2 layer is approximately 1500 & mu;m. After 1800 s of ablation, the SiO2 is completely evaporated, exposing the c/c matrix, at which point the coating has failed. The Sic interlayer improve the ablation resistance due to the continuous SiO2 film formed by the self-sealing and O anti-diffusive properties.

关键词： cVD-Sic interlayer Plasma spraying Ablation resistance c c substrate

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An organic silicone composite coating for protection of Ti-6Al-4V alloy: Oxidation behavior at 600 c in dry air

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cORROSION ScIENcE 2023年 211卷

作者： Lu, Yiliang Xin, Li Li, Xiaonan Zhao, Qingqing Zhang, Kai Du, Yao chen, Zheng Wang, cheng Zhu, Shenglong Wang, Fuhui Univ Sci & Technol China Sch Mat Sci & Engn Shenyang 110016 Peoples R China Chinese Acad Sci Inst Met Res Shi Changxu Innovat Ctr Adv Mat Shenyang 110016 Peoples R China Jiangsu JITRI Rd Engn Technol & Equipment Res Inst Xuzhou 220005 Peoples R China Shenyang Natl Lab Mat Sci Shenyang 110016 Peoples R China Northeastern Univ Sch Mat Sci & Engn Shenyang 110819 Peoples R China AECC Shenyang Liming Aero Engine Co LTD Shenyang 110043 Peoples R China

A new organic silicone composite coating modified by Al, ZrO2, quartz and PbO-SiO2-Al2O3 glass powders was developed to protect Ti-6Al-4V alloy. During oxidation at 600 degrees c in dry air, the coating was oxidized and formed an inorganic composite coating composed of amorphous silica framework and fillers which greatly decreased oxidation rate of substrate. Al2SiO5 formed in coating due to reaction of Al with glass. Glass powders with softening point of 385 degrees c may play important roles in improving coating protectiveness because they can flow to fill the cavities formed by oxidation of organic components in coating at 600 degrees c.

关键词： A Ti-6Al-4V Organic silicone coating B XRD TEM c High temperature Oxidation

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Hayatine inhibits amino acid-induced mTORc1 activation as a novel mTOR-Rag A/c interaction disruptor

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BIOcHEMIcAL AND BIOPHYSIcAL RESEARcH cOMMUNIcATIONS 2021年 583卷 71-78页

作者： Lu, Meiling Yu, Lei Yang, Yanrong Zhu, Jiali Qiang, Sujing Wang, Xinbo Wang, Jia Tan, Xiao Wang, Weifeng Zhang, Yue Wang, Weichao Xie, Jian chen, Xinyan Wang, Hongbing cui, Xianghuan Ge, Xin Tongji Univ Shanghai Peoples Hosp 10 Sch Life Sci & Technol Dept Cent Lab Shanghai 200072 Peoples R China Tongji Univ Shanghai Peoples Hosp 10 Dept Clin Lab Med Med Sch Shanghai 200072 Peoples R China Tongji Univ Shanghai Peoples Hosp 10 Canc Ctr Med Sch Shanghai 200072 Peoples R China Tongji Univ Putuo Dist Peoples Hosp Sch Life Sci & Technol Shanghai 200060 Peoples R China

Abnormal activation of the mechanistic target of rapamycin (mTOR) signaling is commonly observed in many cancers and attracts extensive attention as an oncology drug discovery target, which is encouraged by the success of rapamycin and its analogs (rapalogs) in treatment of mTORc1-hyperactive cancers in both pre-clinic models and clinical trials. However, rapamycin and existing rapalogs have typically short lasting partial responses due to drug resistance, thereby triggering our interest to investigate a potential mTORc1 inhibitor that is mechanistically different from rapamycin. Here, we report that hayatine, a derivative from cissampelos, can serve as a potential mTORc1 inhibitor selected from a natural compound library. The unique properties owned by hayatine such as downregulation of mTORc1 activities, induction of mTORc1's translocation to lysosomes followed by autophagy, and suppression on cancer cell growth, strongly emphasize its role as a potential mTORc1 inhibitor. Mechanistically, we found that hayatine disrupts the interaction between mTORc1 complex and its lysosomal adaptor RagA/c by binding to the hydrophobic loop of Ragc, leading to mTORc1 inhibition that holds great promise to overcome rapamycin resistance. Taken together, our data shed light on an innovative strategy using structural interruption-based mTORc1 inhibitors for cancer treatment. (c) 2021 Elsevier Inc. All rights reserved.

关键词： Hayatine mTOR Rag A c Rapamycin

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correlation between Non-Structural carbohydrates and c:N:P Stoichiometric Ratio of Haloxylon ammodendron under Different Water-Salt Gradients

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FORESTS 2023年第6期14卷 1185-1185页

作者： Yang, Fang Lv, Guanghui Qie, Yadong Xinjiang Univ Sch Ecol & Environm Urumqi 830017 Peoples R China Minist Educ Key Lab Oasis Ecol Urumqi 830017 Peoples R China Minist Educ Xinjiang Jinghe Observat & Res Stn Temperate Deser Jinghe 833300 Peoples R China Guangxi Univ Coll Forestry Guangxi Key Lab Forest Ecol & Conservat Nanning 530004 Peoples R China

Growth is restricted by both water and phosphorus (P), and balancing the relationship between non-structural carbohydrates (NScs) and carbon: nitrogen: phosphorus (c:N:P) is essential for Haloxylon ammodendron to adapt to arid habitats. The survival and growth strategies of the dominant species H. ammodendron in a desert ecosystem were examined in order to better serve the restoration of degraded ecosystems and desertification control. Three water and salt gradients (high water and high salinity, medium water and salinity, and low water and low salinity) in the Aibi Lake Reserve were selected. We analyzed the accumulation and distribution of NScs in the assimilation branches and secondary branches of H. ammodendron and the changes in the measurement ratio characteristics of c:N:P, as well as the soil organic carbon (SOc), total nitrogen (TN), and total phosphorus (TP) content. The results showed that: (1) With the decrease of soil water and salt content, the basal diameter, plant height, crown area, and NSc content of H. ammodendron significantly decreased. This morphological adjustment in the aboveground part is similar to a "self thinning" behavior, aimed at reducing transpiration area and balancing carbon distribution in the body. The carbon accumulation in the body helps the H. ammodendron to resist the dual stresses of drought and salt. (2) With the decrease of water and salt content, the c content of assimilating branches increased significantly, while there was no significant change in secondary branches. However, the N and P content of both branches decreased significantly, and the N: P of both branches was greater than 16, indicating that it was mainly limited by P. (3) The NSc of the two branches was significantly negatively correlated with c, and significantly positively correlated with N and P, and there was a strong positive correlation between the assimilation branches NSc: c: P and NSc: c: P. The synthesis and accumulation of NSc of H. ammodendron wer

关键词： Haloxylon ammodendron different water-salt gradients non-structural carbohydrates c N P stoichiometric ratio

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