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Estimate constituent properties of 3D needle-punched c/Sic composites from hysteresis loops

INTERNATIONAL JOURNAL OF FATIGUE 2023年第1期170卷

作者： Li, Longbiao Liu, Yufeng Wang, Yalei Nanjing Univ Aeronaut & Astronaut Coll Civil Aviat 29 Jiangjun Ave Nanjing 211106 Peoples R China China Acad Launch Vehicle Technol Beijing 100076 Peoples R China Cent South Univ Powder Met Res Inst Changsha 410083 Peoples R China

To improve the mechanical properties of fiber-reinforced ceramic-matrix composites (cMcs), it is necessary to establish the relationship between the composite's constituent properties and macro mechanical properties. In this paper, a hysteresis-based micromechanical method was adopted to obtain the constituent properties of four different types of 3D needle-punched c/Sic composites. Hysteresis-based damage parameters (i.e., inverse tangent modulus (ITM), hysteresis width, residual strain, hysteresis modulus, and damage factor) were derived from the hysteresis theory. Through analysis of the experimental monotonic tensile and cyclic hysteresis curves, the composite's constituent properties (i.e., interface properties and thermal residual stress, etc.) and mechanical properties (i.e., first matrix cracking stress, interface debonding stress, and ultimate tensile strength, etc.) were obtained. Relationship between the composite's constituent properties and mechanical properties was established. Using the estimated composite's constituent properties and developed micromechanical constitutive models, the experimental monotonic and cyclic tensile loading/unloading curves were predicted.

关键词： c Sic Interface properties Thermal residual stress First matrix cracking stress Tensile Hysteresis loops

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Lead as an effective facilitator for ethanol electrooxidation on Rh catalyst in alkaline media: RhPb/c vs RhRu/c

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JOURNAL OF ELEcTROANALYTIcAL cHEMISTRY 2023年第1期936卷

作者： Xiao, Wengui Li, Susu Liu, Jiaxin Fan, Jiahe Ma, Liang cai, Weiwei China Univ Geosci Fac Mat Sci & Chem Sustainable Energy Lab Wuhan 430074 Peoples R China

Rh-based catalysts have attracted much attention due to their ability to efficiently break c-c bonds in ethanol oxidation reaction(EOR), while pure Rh catalyst have low EOR activity. It is important to improve the EOR activity of Rh-based catalyst. Herein, we have been successfully synthesized carbon supported Rh, Rh-Pb, and Rh-Ru alloy catalysts. The catalytic activity of RhPb/c for ethanol oxidation is 0.96 mA/cm2, which is 8 times than that of Rh/c. The steady-state current density of RhPb/c at 0.5 V is 17 and 20 times higher than that of RhRu/c and Rh/c, respectively. The results show that adding a small portion of lead significantly enhanced the Rh-based catalyst activity, stability, and anti-poisoning ability during EOR in alkaline media. Moreover, the Tafel slope of RhPb/c catalyst for EOR is 118 mVdec-1, which is similar with that of Pt/c (116 mVdec-1), while the Tafel slope of RhRu/c is 77 mVdec-1, similar to that of Rh/c(87 mVdec-1). The cO-stripping potential of RhRu/c, Rh/c and RhPb/c is 0.535 V, 0.573 V and 0.601 V, respectively. combined with the cyclic voltammetry, chronoamperometry, cO-stripping and Tafel analysis, it is concluded that for RhRu/c catalyst, the improvement of EOR is mainly attributed to the bifunctional mechanism, while for RhPb/c catalyst, the ensemble effect and the electronic effect of Pb is essential to the improvement of EOR.

关键词： Ethanol electro-oxidation Rh-based catalyst RhPb c RhRu c

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LOW-TEMPERATURE cARBONIZATION OF AcTIVE cENTERS IS THE REASON OF Pd/c cATALYSTS DEAcTIVATION

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JOURNAL OF STRUcTURAL cHEMISTRY 2021年第1期62卷 163-170页

作者： Troitskii, S. Yu. Nartova, A. V. Moroz, E. M. Russian Acad Sci Boreskov Inst Catalysis Siberian Branch Novosibirsk Russia

Physicochemical and catalytic properties of Pd/c catalysts before and after the deactivation as a result of a dimethylbenzylamine debenzylation-acylation reaction are compared. A comprehensive analysis conducted by a number of methods (chemisorption, X-ray photoelectron spectroscopy, electron microscopy, X-ray diffraction) showed that a tenfold loss of the catalyst activity in the reaction conducted in soft conditions (atmospheric H-2 pressure, 25 degrees c) is related to the formation of a nanoscale graphite phase. While this phenomenon is common for high temperature reactions, it is first discovered at low temperatures.

关键词： Pd nanoparticles TEM XRD RFES Pd c debenzylation catalyst active centers deactivation

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D4F alleviates the c/EBP homologous protein-mediated apoptosis in glycated high-density lipoprotein-treated macrophages by facilitating autophagy

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EXPERIMENTAL BIOLOGY AND MEDIcINE 2021年第24期246卷 2595-2609页

作者： Tian, Hua Zhang, Zhaoqiang Han, Xiaoyan Pan, Tianqi Tao, Geru Jiao, Peng Zhai, Lei Yang, Libo Wang, Xiaoxu Yao, Yilin Qin, Shucun Yao, Shutong Shandong First Med Univ & Shandong Acad Med Sci Key Lab Atherosclerosis Univ Shandong Tai An 271000 Shandong Peoples R China Shandong First Med Univ & Shandong Acad Med Sci Inst Atherosclerosis Tai An 271000 Shandong Peoples R China Shandong Univ Tradit Chinese Med Coll Tradit Chinese Med Jinan 250355 Peoples R China Shandong First Med Univ & Shandong Acad Med Sci Coll Basic Med Sci Tai An 271000 Shandong Peoples R China Shandong First Med Univ & Shandong Acad Med Sci Coll Stomatol Tai An 271000 Shandong Peoples R China Cent Hosp Taian Dept Endocrinol Tai An 271000 Shandong Peoples R China

The present study aimed to investigate the role of D4F, an apolipoprotein A-I mimetic peptide, in macrophage apoptosis induced by the glycated high-density lipoprotein (gly-HDL)-induced endoplasmic reticulum (ER) stress c/EBP homologous protein (cHOP) pathway, and unravel the regulatory role of autophagy in this process. Our results revealed that except for suppressing the accumulation of lipids within RAW264.7 macrophages caused by gly-HDL, D4F inhibited gly-HDL-induced decrease in the cell viability and increase in lactate dehydrogenase leakage and cell apoptosis, which were similar to 4-phenylbutyric acid (PBA, an ER stress inhibitor). Besides, similar to PBA, D4F inhibited gly-HDL-induced ER stress response activation evaluated through the decreased PERK and eIF2 alpha phosphorylation, together with reduced ATF6 nuclear translocation as well as the downregulation of GRP78 and cHOP. Interestingly, D4F facilitated gly-HDL-triggered activation of autophagy, measured as elevated levels of beclin-1, Lc3-II, and ATG5 expressions in macrophages. Furthermore, the inhibition effect of D4F on gly-HDL-induced ER stress-cHOP-induced apoptosis of macrophages was restrained after beclin-1 siRNA and 3-methyladenine (3-MA, an inhibitor of autophagy) treatments, while this effect was further reinforced after rapamycin (Rapa, an inducer of autophagy) treatment. Furthermore, administering D4F or Rapa to T2DM mice upregulated Lc3-II and attenuated cHOP expression, cell apoptosis, and atherosclerotic lesions. However, the opposite results were obtained when 3-MA was administered to these mice. These results support that D4F effectively protects macrophages against gly-HDL-induced ER stress-cHOP-mediated apoptosis by promoting autophagy.

关键词： D4F autophagy apoptosis c EBP homologous protein macrophages glycated high-density lipoprotein

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Insights into nitrite accumulation and microbial structure in partial denitrification (PD) process by the combining regulation of c/N ratio and nitrate concentration

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JOURNAL OF ENVIRONMENTAL cHEMIcAL ENGINEERING 2023年第3期11卷

作者： Zhang, Miao Tan, Yufei Fan, Yajun Wu, Jun Yu, Lintang Yangzhou Univ Coll Environm Sci & Engn Yangzhou 225127 Peoples R China Yangzhou Polytech Inst Yangzhou 225127 Peoples R China

The influence of nitrate (NO3- -N) concentrations (40, 80 mg/L marked as R40 and R80) and carbon/nitrogen (c/N) ratios (0.8,1.5, 2.5, 3.5, 4.5) on nitrite (NO2- -N) accumulation in partial denitrification (PD) process was investigated. The results proved that R40-3.5 and R80-2.5 systems showed the optimal NO2- -N contents and nitrate-tonitrite transformation ratio (NTR) values of 14.88, 29.77 mg/L and 52.87 %, 59.12 % with strong resistance to low temperature (12.5-3.8 degrees c). Batch tests displayed the NO2- -N accumulation mechanism via substrate transformations, and the metabolic pathways of nitrogen and carbon for PD and complete denitrification were also compared. Based on the Monod equation, the half-saturation constants of 58.33 and 61.20 mg/L were estimated with zero-order reaction for NO3- -N and NO2- -N reduction, showing a tighter affinity to NO3- -N concentration. Proteobacteria, Bacteroidota, Acidobacteriota and chloroflexi were the four dominant phyla with total percentages of 85.16-94.55 % and 90.81-96.85 % in R40 and R80 groups, while Thauera, Flavobacterium contributing to NO2- N accumulation reached up to 42.79 % and 52.13 % in the R40-3.5 and R80-2.5 systems. The above discussion demonstrated that lower c/N ratio and higher NO3- -N concentration were more favorable for the PD formation.

关键词： Partial denitrification c N ratio NO3--N concentration Denitrification kinetics NO2--N accumulation Microbial community

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Effect of pistachio shell as a carbon source to regulate c/N on simultaneous removal of nitrogen and phosphorus from wastewater

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BIORESOURcE TEcHNOLOGY 2023年 367卷 128234页

作者： chen, Hongwei Hu, Xiaobing Song, Weiwei Wang, Zhenzhen Li, Man Liu, Haoyu Li, Jingjing Anhui Univ Technol Sch Architectural Engn Dept Municipal Engn Maanshan 243002 Anhui Peoples R China Minist Educ Engn Res Ctr Water Purificat & Utilizat Technol Ba Maanshan 243002 Anhui Peoples R China

Acid-pretreated pistachio shells were used as carbon sources to investigate the effects of carbon source dosage on simultaneous nitrogen and phosphorus removal under different carbon/nitrogen (c/N) ratios (7, 9, and 11). Results showed that c/N was positively correlated with mixed liquor suspended solids (MLSS) (R2 = 0.998, p < 0.01) and f value (R2 = 0.975, p < 0.05). Moreover, it was negatively correlated with the sludge volume index (SVI) (R2 = -0.959, p < 0.05). c/N was also significantly negatively related to chemical oxygen demand removal rate (R2 = -0.986, p < 0.05) and positively related to ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) removal rate (p < 0.05), the correlation coefficients were 0.992, 0.990 and 0.994, respectively. In the reactor with c/N of 11, the MLSS concentration and f value were the highest, the SVI was the lowest, and the removal efficiencies of NH4+-N (85.49 % +/- 1.96 %), TN (84.19 % +/- 1.42 %) and TP (94.10 % +/- 1.67 %) were the highest. Furthermore, the relative abundance of denitrifying bacteria was the highest in the reactor. The abundance of nitrifying bacteria and phosphorus-removal bacteria was also relatively high.

关键词： Pistachio shell c N Low-carbon-source sewage Simultaneous nitrogen and phosphorus removal Microbial community structure

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Synthesis of a novel series of -benzothiazepine-c-fi-D-glycoside derivatives in a facile one-pot method and insight into their anti-oxidant properties

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JOURNAL OF MOLEcULAR STRUcTURE 2023年第1期1281卷

作者： Pradhan, Sheersha Muthuvel, Panneerselvam Das, Thangamuthu Mohan Cent Univ Tamil Nadu CUTN Sch Basic & Appl Sci Dept Chem Thiruvarur 610005 India Univ Madras Dept Organ Chem Guindy Campus Chennai 600025 India

The development of seven-membered heterocyclic scaffolds, namely benzothiazepine, has gained much recognition in mild environmentally friendly conditions such as low temperature and short reaction time due to its vast medicinal pertinence. A novel class of [1,5]-benzothiazepine-c -fi-D-glycosides was synthe-sized in a facile one-pot method from a, fi- unsaturated -b -c-glycosidic ketones where the use of p-TSA had shown a better result. The fi-anomeric forms of the c-glycosidic compounds were assigned from 1 H NMR spectroscopy. Studies propose that the series of [1,5]-benzothiazepine-based fi-c-glycosides showed moderate anti-oxidant activities with maximum inhibitory activity of 60%. The second generation [1,5]-benzothiazepine-fi-c-glycoside (piperonal derivative) with 1,3-benzodioxole-substitution (compound 10d ) especially showed excellent anti-oxidant characteristics at all concentrations ranging from 100 to 600 mu g/mL.(c) 2023 Elsevier B.V. All rights reserved.

关键词： 4 6 O Butylidene D glucopyranose a b unsaturated c glycosidic ketones Benzothiazepine Anti oxidant DPPH

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Manganese exposure during early larval stages of c. elegans causes learning disability in the adult stage

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BIOcHEMIcAL AND BIOPHYSIcAL RESEARcH cOMMUNIcATIONS 2021年 568卷 89-94页

作者： Raj, Vishnu Nair, Agrima Thekkuveettil, Anoopkumar Sree Chitra Tirunal Inst Med Sci & Technol Div Mol Med Trivandrum 695012 Kerala India

Manganese (Mn), even though an essential trace element, causes neurotoxicity in excess. In adults, overexposure to Mn causes clinical manifestations, including dystonia, progressive bradykinesia, disturbance of gait, slurring, and stuttering of speech. These symptoms are mainly because of Mn-associated oxidative stress and degeneration of dopamine neurons in the central nervous system. children with excessive Mn exposure often show learning disabilities but rarely show symptoms associated with dopaminergic neuron dysfunction. It is unclear why Mn exposure shows distinctive clinical outcomes in developing brains versus adult brains. Studies on nematode c. elegans have demonstrated that it is an excellent model to elucidate Mn-associated toxicity in the nervous system. In this study, we chronically exposed Mn to L1 larval stage of the worms to understand the effects on dopamine neurons and cognitive development. The worms showed modified behavior to exogenous dopamine compared to the control. The dopamine neurons showed resistance to neurodegeneration on repeated Mn exposure during the adult stage. As observed in mammalian systems, these worms showed significantly low olfactory adaptive learning and memory. This study shows that c. elegans alters adaptive developmental plasticity during Mn overexposure, modifying its sensitivity towards the metal ion and leads to remodeling in its innate learning behavior. (c) 2021 Published by Elsevier Inc.

关键词： Dopamine Manganese Neurodegeneration Learning c elegans

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Selective oxidation of alcohols to nitriles with high-efficient co-[Bmim]Br/c catalyst system

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cHEMIcAL PAPERS 2021年第8期75卷 3957-3964页

作者： Xia, Yu-Yan Lv, Qing-Yang Yuan, Hua Wang, Jia-Yi Wuhan Inst Technol Minist Educ Key Lab Green Chem Proc Wuhan 430073 Peoples R China

An efficient method for catalyzing the ammoxidation of aromatic alcohols to aromatic nitriles was developed, in which a new heterogeneous catalyst based on transition metal elements was employed, the new catalyst was named co-[Bmim]Br/c-700 and then characterized by X-ray photo-electronic spectroscopy, transmission electron microscope and X-ray diffraction. The reaction was carried out by two consecutive dehydrogenations under the catalysis of co-[Bmim]Br/c-700, which catalytically oxidized the alcohol to the aldehyde, and then the aldehyde was subjected to ammoxidation to the nitrile. The catalyst system was suitable for a wide range of substrates and nitriles obtained in high yields, especially, the conversion rate of benzyl alcohol, 4-methoxybenzyl alcohol, 4-chlorobenzyl alcohol and 4-nitrobenzyl alcohol reached 100%. The substitution of ammonia and oxygen for toxic cyanide to participate in the reaction accords with the theory of green chemistry.

关键词： Alcohol Aldehyde Ammoxidation co-[Bmim]Br c Nitrile

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Fading behavior and wear mechanisms of c/c-Sic brake disc during cyclic braking

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WEAR 2023年第1期526卷

作者： Hui, Yang Liu, Guimin Zhang, Qing Zhang, Yong Zang, Yan Wang, Sijie Shi, Ruidong Acad Army Armored Forces Dept Equipment Maintenance & Remfg Engn Beijing 100072 Peoples R China

In this work, the performances of c/c-Sic brake discs under extreme operating conditions, including cyclic high -temperature and emergency braking of heavy-duty tracked vehicles, were investigated. The friction interface evolution and anti-fading mechanism of c/c-Sic brake discs during cyclic braking were also revealed. The maximum temperature of the c/c-Sic brake discs contact surface during cyclic high-temperature braking reached 663.7 degrees c, while the maximum decay rate was only 9.55%. compared with the iron-based brake discs, the average coefficient of friction (cOF) of the c/c-Sic increased by 14.70% and the wear rate decreased by 306.68% after the 10th braking cycle. A "c + Sic + SiO2" continuous friction film generated during the late stage of braking slowed down the diffusion of oxygen into the matrix, resulting in an excellent performance of the brake discs at high temperatures. Furthermore, the average cOF of the c/c-Sic brake discs was maintained at 0.45-0.50 during cyclic emergency braking. When the friction film was not generated or was destroyed, the cOF mainly depended on the surface asperities. However, when the friction film was completely covered, the cOF decreased and tended to be stable and consistent, suggesting that c/c-Sic brake discs can provide a sufficient and stable braking force at different speeds.

关键词： c c-Sic brake Discs cyclic braking Friction Wear mechanism

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