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Effect of rotary ultrasonic machining on surface structure and ablation resistance of c/c composite

cERAMIcS INTERNATIONAL 2022年第13期48卷 18246-18256页

作者： Shu, Jing Liao, Wenhe Zheng, Kan Abd Elbadia, Tarek Nanjing Univ Sci & Technol Sch Mech Engn Nanjing Jiangsu Peoples R China Mil Tech Coll Mech Design & Prod Dept Cairo Egypt

c/c composite is widely used in aerospace due to excellent high temperature mechanical properties. Improving its ablation resistance has become the focus of attention. Due to anisotropy of composite materials, the difference of thermal conductivity and thermal expansion coefficient between fiber and matrix, surface morphologies affect ablation performance greatly. In particular, fiber exposed length (FEL) and crack had a significant impact on its ablation resistance. Therefore, this paper constructed a FEL theoretical model based on machining damage, and verified that the error of the modified model was within 12 % through experiments. Meanwhile, improvement effect of rotary ultrasonic machining (RUM) was clarified. It is found that RUM reduced FEL by 15%~38% in all fiber angles and decreased the crack pores on machined surface. Then, oxyacetylene ablation experiments on c/c composite surface under conventional machining (cM) and RUM were carried out. The results showed that RUM surface had better ablation resistance, and interface ablation and porosity decreased significantly.

关键词： c c composite RUM Morphology Oxyacetylene ablation

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AN EFFIcIENT IMPLEMENTATION OF LU DEcOMPOSITION IN c

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ADVANcES IN ENGINEERING SOFTWARE AND WORKSTATIONS 1988年第3期10卷 123-130页

作者： MEYER, A Computer Science Department Washington State University Pullman Wa. 99164-1210 USA

An implementation of the well-known LU decomposition method for solving systems of linear equations is presented. Operation counts typically stated for this method are derived from a theoretical analysis of the algorithm and ignore the practical aspects of the implementation. The overhead associated with assessing elements of the two-dimensional coefficient array are explored herein, and seen to be substantial. This overhead is incorporated into the analysis of LU decomposition and new operation counts are developed. By exploiting the addressing capabilities of c the cost of array access is significantly reduced, resulting in an efficient implementation. The techniques employed here can be applied to a wide variety of c programs which utilize multi-dimensional arrays.

关键词： LU decomposition array access compiler c pointers

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Ablative property and mechanism of Sic-cuxSiy modified c/c-Zrc composites prepared by a rapid method

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JOURNAL OF THE EUROPEAN cERAMIc SOcIETY 2023年第11期43卷 4602-4615页

作者： Weng, Yuanqi Yang, Xin chen, Feixiong Fang, cunqian Zhang, Xiaxiang Shi, Anhong Huang, Qizhong Cent South Univ Natl Key Lab Sci & Technol High strength Struct Ma Changsha 410083 Peoples R China Adv Technol & Mat Co Ltd Beijing 100081 Peoples R China Cent South Univ Sch Met & Environm Changsha 410083 Peoples R China

A rapid method was developed to fabricate c/c-Zrc-Sic-cuxSiy composites with low open porosity by precursor infiltration and pyrolysis combining with pressure assisted reactive melt infiltration. Dominant phases of Zrc and Sic with scattered cuxSiy inclusions were present in continuous infiltrated matrix, in which the dimension of submicron Zrc particles displayed gradient change. At ablation test, the heat absorbing effect of cuxSiy-phase and formation of protective ZrO2-SiO2 cover enhanced the ablative property of composites for short-time ablation, causing ablation rates of 30 s ablation reached 1.7 +/- 0.1 mu m/s and 1.3 +/- 0.1 mg/s, respectively. As ablation time extends to 60 s, the massive consumption of Si-phase damaged the integrity of surface oxide cover, but the partial melted ZrO2 improved the viscosity and self-healing ability of ZrO2-SiO2 mixture, protecting substrate from further erosion. Thus, ablation rates were increased and decreased to 3.8 +/- 0.2 mu m/s and 1.2 +/- 0.1 mg/s, respectively.

关键词： c c composites Modification Infiltration High temperature ablation

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Microstructure and properties of c/c-Zrc composites with matrix modification by slurry infiltration

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cERAMIcS INTERNATIONAL 2023年第8期49卷 13074-13080页

作者： Jia, Yan Li, Yong cheng, Haifeng chen, Si'an Natl Univ Def Technol Coll Aerosp Sci & Engn Sci & Technol Adv Ceram Fibers & Composites Lab Changsha 410073 Peoples R China Northwest Inst Nucl Technol Xian 710024 Peoples R China

c/c-Zrc composites are promising thermal structural materials for aerospace applications. However, until now, the reported c/c-Zrc composites exhibited a porous matrix and weaker mechanical properties. In this study, the matrices of c/c-Zrc composites were modified by slurry infiltration in order to improve density and properties. Different slurry powders such as Sic, Zrc, and ZrB2 were used to densify the c/c-Zrc composites. After slurry infiltration, the loose c-Zrc matrix was connected to a dense matrix, and some ceramic powders settled on the surface of the composites. The density of the composites increased from 1.94 to 2.42 +/- 0.06 g cm-3, while the porosity decreased from 39.4 +/- 4.4% to 10.3 +/- 1.9% after infiltration with various slurries. The ablation and mechanical properties of the c/c-Zrc composites improved significantly by matrix modification. The flexural strength of the composites increased from 116 to 269 +/- 21 MPa after slurry infiltration. Furthermore, the ablation properties of c/c-Zrc composites infiltrated with the ZrB2 slurry showed the lowest linear rate (24.7 mu m s-1) and mass recession rate (7.5 mg s-1).

关键词： c c-Zrc composites Microstructure Slurry infiltration Mechanical properties Ablation properties

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High electrochemical performance of Li4Ti5O12/c synthesized by ball milling and direct flaming of acetylene gas as anode for lithium-ion battery

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IONIcS 2019年第11期25卷 5315-5322页

作者： Noerochim, Lukman Maghfiroh, Amalia Ma'rifatul Widyastuti Susanti, Diah Priyono, Slamet Prihandoko, Bambang Sepuluh Nopember Inst Technol Dept Mat & Met Engn Surabaya 60111 Indonesia Indonesian Inst Sci Res Ctr Phys Serpong Indonesia

Li4Ti5O12/c has been successfully synthesized by a solid-state reaction method of Li2cO3 and TiO2 followed by direct flaming of acetylene gas. Li4Ti5O12 with 2-h milling time is indexed as single-phase crystal structure of Li4Ti5O12 (JcPDS 04-0477). The SEM results show particle sizes between 0.192 and 0.360 mu m with a spherical shape, but there is agglomeration due to high temperature when the direct flaming of acetylene gas process is applied. The desired carbon content by direct flaming of acetylene gas is still very low at 0.6% for 10 min and 0.9% for 20 min. Li4Ti5O12 with 10 min of direct flaming of acetylene gas has the highest specific discharge capacity of 210.61 mAh/g. This is attributed to the pure single phase and the higher conductivity of the sample. This result shows that Li4Ti5O12/c synthesized by ball milling and direct flaming of acetylene gas could be a good candidate as anode for lithium-ion battery.

关键词： Li4Ti5O12 c Ball milling Direct flaming Anode Lithium-ion battery

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Assembling plant diversity mitigates greenhouse gas emissions and achieves high nitrogen removal when treating the low-c/N wastewater by constructed wetlands

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ENVIRONMENTAL ScIENcE AND POLLUTION RESEARcH 2023年第1期30卷 228-241页

作者： Jiang, Hang Du, Yuanyuan Han, Wenjuan Wang, Lichunxiao Xiang, chenxu Ge, Ying chang, Jie Zhejiang Univ Coll Life Sci 866 Yuhangtang Rd Hangzhou 310058 Peoples R China Wenzhou Univ Coll Life & Environm Sci Wenzhou 325035 Peoples R China

The low carbon-to-nitrogen (c/N) ratio in wastewater will inhibit pollutant removal, and more seriously, it will cause an increment of nitrous oxide (N2O) emissions of constructed wetlands (cWs). Raising the c/N ratio of wastewater is an effective way to solve this problem, while it may cause secondary pollution and is costly. Assembling plant diversity promotes N removal, while the effects of plant diversity and increasing c/N ratio on global warming potential (GWP) combined by N2O and methane (cH4) are lack of comparison. In this study, 108 cW microcosms were established to explore the effects of increasing the c/N ratio from 1 to 5 and assembling plant diversity on N removal and GHG emissions. Results showed that when the c/N ratio was 1, (1) increasing species richness reduced N2O and cH4 emissions then reduced the GWP by 70%;(2) the presence of Arundo donax in microcosms reduced GWP by 72%;(3) an A. donax x Tradescantia fluminensis x Reineckia carnea mixture resulted in a high N removal and decreased the GWP per g N removal by 92% with a cost increment of 0.05 USD per m(3) wastewater treated;and (4) as the c/N ratio increasing to 5, the GWP per g N removal of monocultures was reduced by 96%, but the cost increased by at least 0.29 USD per m(3) wastewater treated. In summary, configuring plant diversity in cWs is an efficient, clean, and cost-effective measure to treat wastewater with a low c/N ratio.

关键词： c N ratio Nitrous oxide Methane Species richness Species identity Plant uptake Denitrification cost-effective

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mTOR regulates TLR-induced c-fos and Th1 responses to HBV and HcV vaccines

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Virologica Sinica 2015年第3期30卷 174-189页

作者： Li He Aiping Zang Min Du Dapeng Ma chuanping Yuan chun Zhou Jing Mu Huanjing Shi Dapeng Li Xulin Huang Qiang Deng Jianhua Xiao Huimin Yan Lijian Hui Ke Lan Sidong Xiong Xiaoxia Li Zhong Huang Hui Xiao Institute of Biology and Medical Sciences Soochow University Unit of Immune Signaling and Regulation Key Laboratory of Molecular Virology & Immunology Institut Pasteur of Shanghai Chinese Academy of Sciences Unit of Vaccinology and Anti-viral Strategies Key Laboratory of Molecular Virology & Immunology Institut Pasteur of Shanghai Chinese Academy of Sciences Unit of Tumor Virology Key Laboratory of Molecular Virology & Immunology Institut Pasteur of ShanghaiChinese Academy of Sciences Institute of Pathogenic Biology University of South China Mucosal Immunity Research Group State Key Laboratory of Virology Wuhan Institute of Virology Chinese Academy of Sciences State Key Laboratory of Cell Biology Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Department of Immunology Lerner Research Institute Cleveland Clinic Foundation Vaccine Center Institut Pasteur of Shanghai Chinese Academy of Sciences

Although IL-12 plays a critical role in priming Th1 and cytotoxic T lymphocyte(cTL) responses, Toll-like receptor(TLR) signaling only induces low amounts of IL-12 in dendritic cells and macrophages, implying the existence of stringent regulatory mechanisms. In this study, we sought to uncover the mechanisms underlying TLR-induced IL-12 expression and the Th1 response. By systemic screening, we identified a number of protein kinases involved in the regulation of TLRinduced IL-12 expression. In particular, PI3 K, ERK, and m TOR play critical roles in the TLR-induced Th1 response by regulating IL-12 and IL-10 production in innate immune cells. Moreover, we identified c-fos as a key molecule that mediates m TOR-regulated IL-12 and IL-10 expression in TLR signaling. Mechanistically, m TOR plays a crucial role in c-fos expression, thereby modulating NFκB binding to promoters of IL-12 and IL-10. By controlling the expression of a special innate gene program, m TOR can specifically regulate the TLR-induced T cell response in vivo. Furthermore, blockade of m TOR by rapamycin efficiently boosted TLR-induced antigen-specific T and B cell responses to HBV and HcV vaccines. Taken together, these results reveal a novel mechanism through which m TOR regulates TLR-induced IL-12 and IL-10 production, contributing new insights for strategies to improve vaccine efficacy.

关键词： Toll-like receptor(TLR) mTOR vaccine hepatitis B virus(HBV) hepatitis c virus(HcV) adjuvant c-fos

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comparison of different mass spectrometry techniques in the measurement of L-[ring-13c6]phenylalanine incorporation into mixed muscle proteins

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JOURNAL OF MASS SPEcTROMETRY 2013年第2期48卷 269-275页

作者： Zabielski, Piotr Ford, G. charles Persson, X. Mai Jaleel, Abdul Dewey, Jerry D. Nair, K. Sreekumaran Mayo Clin Div Endocrinol Diabet Metab & Nutr Rochester MN 55905 USA Mayo Clin CTSA Metabol Core Rochester MN 55905 USA

Precise measurement of low enrichment of stable isotope labeled amino-acid tracers in tissue samples is a prerequisite in measuring tissue protein synthesis rates. The challenge of this analysis is augmented when small sample size is a critical factor. Muscle samples from human participants following an 8h intravenous infusion of L-[ring-13c6]phenylalanine and a bolus dose of L-[ring-13c6]phenylalanine in a mouse were utilized. Liquid chromatography tandem mass spectrometry (Lc/MS/MS), gas chromatography (Gc) MS/MS and Gc/MS were compared to the Gc-combustion-isotope ratio MS (Gc/c/IRMS), to measure mixed muscle protein enrichment of [ring-13c6]phenylalanine enrichment. The sample isotope enrichment ranged from 0.0091 to 0.1312 molar percent excess. As compared with Gc/c/IRMS, Lc/MS/MS, Gc/MS/MS and Gc/MS showed coefficients of determination of R2=0.9962 and R2=0.9942, and 0.9217 respectively. However, the precision of measurements (coefficients of variation) for intra-assay are 13.0%, 1.7%, 6.3% and 13.5% and for inter-assay are 9.2%, 3.2%, 10.2% and 25% for Gc/c/IRMS, Lc/MS/MS, Gc/MS/MS and Gc/MS, respectively. The muscle sample sizes required to obtain these results were 8 mu g, 0.8 mu g, 3 mu g and 3 mu g for Gc/c/IRMS, Lc/MS/MS, Gc/MS/MS and Gc/MS, respectively. We conclude that Lc/MS/MS is optimally suited for precise measurements of L-[ring-13c6]phenylalanine tracer enrichment in low abundance and in small quantity samples. copyright (c) 2013 John Wiley & Sons, Ltd.

关键词： L-[ring-13c6]phenylalanine enrichment Gc c IRMS Lc MS MS Gc MS MS Gc MS mixed muscle proteins amino-acid tracer tandem mass spectrometry

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Structural characteristics and ablative behavior of YF3 modified c/c-Zrc-Sic composites and their preparation by molten salt assisted reactive melt infiltration

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JOURNAL OF THE EUROPEAN cERAMIc SOcIETY 2023年第4期43卷 1303-1314页

作者： Shen, Yuzhu Sun, Wei Xu, Yonglong Zhang, Hongbo Xiong, Xiang Cent South Univ State Key Lab Powder Met Changsha Peoples R China

In order to further improve the ablative resistance of c/c-Zrc-Sic composites, YF3 modified c/c-Zrc-Sic com-posites were prepared by molten salt assisted reactive melt infiltration, and the infiltration mechanism and ablative behavior of the composites were discussed. After fluorination, diffusion, adsorption and reaction of yttrium in ionic melt generated by K2ZrF6, YF3 was generated inside c/c-Zrc-Sic composites, which effectively seals the existing pores and cracks in c/c-Zrc-Sic material. YF3 modified c/c-Zrc-Sic composites can form yttrium oxide stabilized zirconia during the ablation process, and improve the ablation stability of the oxide layer compared with c/c-Zrc-Sic composites, the mass ablation rate and linear ablation rate of YF3 modified c/c-Zrc-Sic composites are reduced by 42.61% and 90.14% respectively.

关键词： Molten salt assisted reactive melt infiltration c c-Zrc-Sic modified byYF3 The ablation performance

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Flexural strength and wear resistance of c/c-Sic brake materials improved by introducing Sic ceramics into carbon fiber bundles

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cERAMIcS INTERNATIONAL 2021年第17期47卷 24130-24138页

作者： Ma, Xu Sun, Haodong Kou, Sijie Fan, Shangwu Deng, Juanli Zhang, Litong cheng, Laifei Northwestern Polytech Univ Sci & Technol Thermostruct Composite Mat Lab Xian 710072 Shaanxi Peoples R China Changan Univ Sch Mat Sci & Engn Xian 710064 Shaanxi Peoples R China

In this work, we adopted PIP technology to introduce Sic ceramics into the carbon fiber bundles of c/c-Sic composites. The obtained c/c-Sic composites containing PIP-Sic exhibited improved flexural strength. Meanwhile, the strength difference was reduced in in-plane and vertical directions. Fracture morphology revealed that the introduction of Sic into the fiber bundles broadened available toughening mechanism of the prepared composites. The braking performance of the materials was tested on an MM-1000 dynamometer. After braking at different speeds, we analyzed wear rates, variations in friction coefficient, and the morphological evolution of the friction surface. The results indicated that the introduction of Sic into the fiber bundles enhanced the abrasive resistance of local c/c regions, which yielded a significant reduction of the wear rates.

关键词： Polymer infiltration and pyrolysis (PIP) Sic c c-Sic composites Flexural strength Friction and wear

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