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The effect of carbon source addition order during sol-gel process on the properties of c/c-Zrc-Sic composites

cERAMIcS INTERNATIONAL 2021年第24期47卷 35366-35377页

作者： Zeng, chen Zhang, Mingyu He, Hanwei Wang, Xiaodong Tong, Kai Wang, Yafeng Xu, Ping Zheng, Lei Zeng, Guang Su, Zhean Huang, Qizhong Cent South Univ Powder Met Res Inst Natl Key Lab Sci & Technol High Strength Struct M Changsha 410083 Peoples R China Cent South Univ Powder Met Res Inst Changsha 410083 Peoples R China

Sol-gel is a promising technology to prepare the c/c-Zrc-Sic composites. However, carbon fiber erosion caused by carbothermal reduction severely degrades properties of the composites. At present study, the addition order of carbon source during sol-gel process was optimized to improve the microstructure, mechanical property and ablation resistance of the composites. Results show that adding phenolic resin before gelation combined with deposited pyrocarbon interlayer around the carbon fibers can greatly alleviate the degradation of the c/ c-Zrc-Sic composites by reducing the carbon fiber erosion. The composites thus prepared delivered the flexural strength, mass and linear ablation rates are 162.58 MPa, 0.147 mg/(cm2.s) and 0.0098 mm/s, respectively, which are 449% higher, 9.26% lower and 38.36% lower than those of the counterpart that added phenolic resin after gelation. The excellent performance is attributed to little erosion of the carbon fibers and the dense matrix of Zrc-Sic ceramics obtained from adding carbon source before gelation during the sol-gel process.

关键词： c c-Zrc-Sic composites Sol-gel Fiber erosion Mechanical properties Ablation resistance

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In situ tensile damage characterization of c/c composites through X-ray computed tomography and digital volume correlation

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cERAMIcS INTERNATIONAL 2023年第7期49卷 10471-10480页

作者： Li, Wudi Jian, Yingjie Zhou, Xingui Wang, Honglei Natl Univ Def Technol Sci & Technol Adv Ceram Fibers & Composites Lab Changsha 410073 Peoples R China

carbon fiber reinforced carbon matrix (c/c) composites have been used in aerospace applications due to their excellent performance. Exploring their failure mechanisms is a subject of extensive research. Nowadays, to obtain information about changes in the failure processes, a technology known as in situ X-ray computed to-mography is used. In this paper, tensile loads were applied to 3D fine-woven punctured and needle-punched c/c composites perpendicular to the punctured and needle-punched directions. In situ X-ray computed tomography was employed to observe damage development, and digital volume correlation was used to assess the laboratory X-ray computed tomographs to measure local strains. Assimilation of pores is observed in c/c composites, with cracks evolving from original micro-pores. While fine-woven punctured c/c composites present an elegant linear failure, needle-punched c/c composites present a traditional non-linear failure. This difference is due to the different structures of the preforms. Furthermore, the c/c composites are weak at the sites where they are punctured or needle-punched.

关键词： X-ray computed tomography Digital volume correlation c c composite Mechanical behavior

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Influence of silicon infiltration on the wear and oxidation resistance of hot-pressed B4c/c(graphite) composites

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cERAMIcS INTERNATIONAL 2021年第24期47卷 34927-34939页

作者： Jiang, Tao Han, Manman Fu, Jia Xian Shiyou Univ Sch Mat Sci & Engn Xian 710065 Shaanxi Peoples R China

B4c/c(graphite) composites were produced using Hot-pressing. However, the composites exhibited low surface hardness, low wear resistance as well as low oxidation resistance. The hot-pressed B4c/c(graphite) composites were processed via silicon infiltration procedure at 1550 degrees c for 2 h in the vacuum condition to refine the wear resistance, surface hardness, and oxidation resistance of the B4c/c(graphite) composites. The silicon infiltration process resulted in the fabrication of a surface layer based on silicon carbide and silicon upon the B4c/c (graphite) composites surface. The surface layer of the silicon infiltrated B4c/c(graphite) composites, primarily comprising silicon carbide and silicon, was examined for its phase composition and microstructure. The oxidation resistance, wear resistance, and surface hardness of B4c/c(graphite) composites subjected to silicon infiltration was additionally examined. The XRD results confirmed that silicon carbide and silicon-based layer existed on the surface of B4c/c(graphite) composites, which was produced as a result of the silicon infiltration process. The surface of silicon infiltrated B4c/c(graphite) composites exhibited a 300-400 mu m thick covering of silicon carbide and silicon. The deposited layer also exhibited a dense and compact microstructure. When compared to hot-pressed B4c/c(graphite) composites, the surface hardness and wear resistance of the composites resulting after silicon infiltration were significantly enhanced. Silicon infiltrated B4c/c(graphite) composites possess a surface hardness of 16-17 GPa. The oxidation resistance of the silicon infiltrated B4c/c(graphite) composites was considerably enhanced as compared to the hot-pressed B4c/c(graphite) composites. So the silicon infiltrated B4c/c(graphite) composites exhibited high surface hardness, excellent wear resistance and excellent oxidation resistance in comparison with the hot-pressed B4c/c(graphite) composites.

关键词： A Hot pressing B composites c Hardness Wear resistance

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Value of cystatin c in predicting atrial fibrillation recurrence after radiofrequency catheter ablation

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Journal of Geriatric cardiology 2018年第12期15卷 725-731页

作者： Li-Li JIN Ling YOU Rui-Qin XIE Department of Cardiology the Second Hospital of Hebei Medical UniversityShijiazhuangChina

Backgroud Recent studies have demonstrated that cystatin c is a valuable risk marker for cardiovascular disease morbidity and ***,we hypothesized that the pre-ablation cystatin c level was associated with post-ablation atrial fibrillation(AF)*** 207 patients were enrolled and completed in this prospective observational *** with AF scheduled for receive radiofrequency catheter ablation(RFcA)therapy were screened for the *** ablation therapy,electrocardiogram,24 h holter monitor,transesophageal echocardiography,serum cystatin c,high-sensitivity c-reactive protein,creatinine levels,and routine blood examinations were *** ablation,patients were followed up every week for the first month,and then at 2,3,6,9,and 12 ***,patients came back to out-patient clinic every six months *** or 24 h holter monitor were repeated if the patient experienced palpitations or every six *** recurrence was defined as atrial flbrillation/atrial flutter or atrial tachycardia lasting≥30 seconds within three months after *** compared to patients with no AF recurrence,patients with recurrence had longer AF history(P=0.007),more early recurrence(P=0.000),a larger left atrium(P=0.004),and higher pre-ablation cystatin c levels(P=0.000).Multivariate regression analysis revealed that cystatin c and left atria(LA)diameter were risk factors for AF *** adjusting for LA diameter,the risk of AF recurrence increased 30%with every milligram cystatin c elevation(95%cI:1.117-1.523).conclusions Pre-ablation cystatin c levels were associated with AF recurrence after RFcA therapy,an optimal cut-off value of 1.190 mg/L(sensitivity=0.576;specificity=0.851).

关键词： Atrial fibrillation catheter ablation cystatin c Recurrence

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correlation Between Unfolded States of Apocytochrome c and Its Ability to Pass Lipid Bilayer

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Science china chemistry 1994年第11期37卷 1341-1349页

作者：王贤树童俊超韩学海杨福愉 National Laboratory of Biomacromolecules Institute of BiophysicsAcademia SinicaBeijing 100101PRC

In contrast to the horse heart apocytochrome c,the chicken heart apocytochrome c under-went a conformational change from random coil to partial folding during a renaturation *** theapocytochrome horse heart and that of chicken heart c were subjected to a translocation assay in vitro usinglarge trypsin-enclosed unilamellar vesicles from soybean phospholipids,the ability of the chicken heart apoc-ytochrome c to penetrate into the liposomes was found to decrease markedly with the renaturation procedure,while that of horse heart apocytochrome c remained relatively *** from circular dichroismmeasurement on the induction of secondary folding of these two species of apocytochrome c upon interactionwith soybean phospholipid vesicles suggested that a more flexible structure of apocytochrome c embedded inthe lipid matrix be required for its efficient translocation across the bilayer.

关键词： apocytochrome c translocation unfolded state

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Serum cystatin c levels are negatively correlated with post-stroke cognitive dysfunction

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Neural Regeneration Research 2020年第5期15卷 922-928页

作者： Dao-Xia Guo Zheng-Bao Zhu chong-Ke Zhong Xiao-Qing Bu Li-Hua chen Tan Xu Li-Bing Guo Jin-Tao Zhang Dong Li Jian-Hui Zhang Zhong Ju chung-Shiuan chen Jing chen Yong-Hong Zhang Jiang He Department of Epidemiology School of Public Health and Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric DiseasesMedical College of Soochow UniversitySuzhouJiangsu ProvinceChina Department of Epidemiology Tulane University School of Public Health and Tropical MedicineNew OrleansLAUSA Department of Neurology Siping Central HospitalSipingJilin ProvinceChina Department of Neurology the 88th Hospital of People’s Liberation ArmyTaianShandong ProvinceChina Department of Internal Medicine Feicheng City People’s HospitalFeichengShandong ProvinceChina Department of Neurology Tongliao Municipal HospitalInner Mongolia Autonomous RegionChina Department of Neurology Kerqin District First People’s Hospital of Tongliao CityInner Mongolia Autonomous RegionChina Department of Medicine Tulane University School of MedicineNew OrleansLAUSA

Stroke is the leading cause of death and long-term disability worldwide,and cognitive impairment and dementia are major complications of ischemic *** c (cysc) has been found to be a neuroprotective factor in animal ***,the relationship between cysc levels and cognitive dysfunction in previous studies has revealed different *** prospective observational study investigated the correlation between serum cysc levels and post-stroke cognitive dysfunction at 3 *** from 638 patients were obtained from the china Antihypertensive Trial in Acute Ischemic Stroke (cATIS).cognitive dysfunction was assessed using the Mini-Mental State Examination (MMSE) at 3 months after *** to the MMSE score,308 patients (52.9%) had post-stroke cognitive *** adjusting for potential confounding factors,the odds ratio (95% cI) of post-stroke cognitive dysfunction for the highest quartile of serum cysc levels was 0.54 (0.30–0.98),compared with the lowest *** correlation between serum cysc and cognitive dysfunction was modified by renal function *** observed a negative linear dose-response correlation between cysc and cognitive dysfunction in patients with normal renal function (Plinearity = 0.044),but not in those with abnormal renal *** serum cysc levels were correlated with a low risk of 3-month cognitive dysfunction in patients with acute ischemic stroke,especially in those with normal renal *** current results suggest that cysc is a protective factor for post-stroke cognitive dysfunction,and could be used to treat post-stroke cognitive *** cATIS study was approved by the Institutional Review Boards at Soochow University from china (approval No.2012-02) on December 30,2012,and was registered at *** (identifier ***01840072) on April 25,2013.

关键词： abnormal renal function cognitive dysfunction cystatin c ischemic stroke Mini-Mental State Examination neural regeneration neuroprotective effect normal renal function

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Photoredox catalysis of As(III) by constructed \\c=Sn \\S bonds: Using biomass as templates leads to bio-carbon/SnS 2 nanosheets capable of the ef ficient photocatalytic conversion of As(III) and calcium arsenate capture

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ScIENcE OF THE TOTAL ENVIRONMENT 2020年 732卷 138963页

作者： Xue, Kehui Wang, Jing He, Ren Yang, Tianli Yan, Ying Peng, Yi Omeoga, Uche Wang, Wenlei Cent South Univ Forestry & Technol Coll Sci Changsha 410004 Peoples R China

In this paper, a new interface design strategy for bio‑carbon/SnS 2 nanosheets equipped with c Sn S bonds was proposed by using biomass as a template for the efficient photocatalytic conversion of As(III). The characterization results illustrated that the c Sn S bonds could effectively prevent the agglomeration of SnS 2 , expand the photoresponse range and improve the hydrophilicity of the bio‑carbon/SnS 2 composites while reducing their transfer resistance. Therefore, the construction of c Sn S bonds could more efficiently promote the photoredox catalysis of As(III) to As(V) compared with pure SnS 2 , attributing to the polarization and conjugation effects of the c Sn bonds. Meanwhile, caSO 4 ·nH 2 O ( n = 0, 0.5, 2) could rapidly convert AsO 4 3− into ca 3 (AsO 4 ) 2 precipitates to eliminate arsenic from the aqueous solution in one step. In particular, 7500 μg/L As(III) could not only be photocatalyzed into As(V) but also be converted to ca 3 (AsO 4 ) 2 to achieve the removal of arsenic within only 55 min in the coexistence of caSO 4 . In addition, the electron transfer path in the photocatalytic oxidation system on arsenite was proposed according to the Mott-Schottky (MS) plots of SnS 2 and graphitic carbon. The electron paramagnetic resonance (EPR) results implied that O 2 – and h + were the main active substances in the photooxidation arsenic system and the effect of OH could be negligible. Thus, the possible mechanism of the photocatalytic conversion of As(III) was discussed.

关键词： Bio‑carbon/SnS 2 nanosheets c Sn S bonds Photoredox As(III) caSO 4 ·nH 2 O

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Electrochemical Activation of Li2MnO3 Electrodes at 0 °c and Its Impact on the Subsequent Performance at Higher Temperatures

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MATERIALS 2020年第19期13卷 4388页

作者： Susai, Francis Amalraj Talianker, Michael Liu, Jing Rosy Paul, Tanmoy Grinblat, Yehudit Erickson, Evan Noked, Malachi Burstein, Larisa Frenkel, Anatoly I. Tsur, Yoed Markovsky, Boris Aurbach, Doron Bar Ilan Univ Dept Chem IL-52900 Ramat Gan Israel Bar Ilan Univ Inst Nanotechnol & Adv Mat IL-52900 Ramat Gan Israel Ben Gurion Univ Negev Dept Mat Engn IL-84105 Beer Sheva Israel Manhattan Coll Dept Phys New York NY 10471 USA Technion Israel Inst Technol Dept Chem Engn IL-3200003 Haifa Israel Technion Israel Inst Technol Grand Technion Energy Program IL-3200003 Haifa Israel Tel Aviv Univ Wolfson Appl Mat Res Ctr IL-69978 Tel Aviv Israel SUNY Stony Brook Dept Mat Sci & Chem Engn Stony Brook NY 11794 USA

This work continues our systematic study of Li- and Mn- rich cathodes for lithium-ion batteries. We chose Li2MnO3 as a model electrode material with the aim of correlating the improved electrochemical characteristics of these cathodes initially activated at 0 degrees c with the structural evolution of Li2MnO3, oxygen loss, formation of per-oxo like species (O-2(2-)) and the surface chemistry. It was established that performing a few initial charge/discharge (activation) cycles of Li2MnO3 at 0 degrees c resulted in increased discharge capacity and higher capacity retention, and decreased and substantially stabilized the voltage hysteresis upon subsequent cycling at 30 degrees c or at 45 degrees c. In contrast to the activation of Li2MnO3 at these higher temperatures, Li2MnO3 underwent step-by-step activation at 0 degrees c, providing a stepwise traversing of the voltage plateau at >4.5 V during initial cycling. Importantly, these findings agree well with our previous studies on the activation at 0 degrees c of 0.35Li(2)MnO(3)center dot 0.65Li[Mn0.45Ni0.35co0.20]O-2 materials. The stability of the interface developed at 0 degrees c can be ascribed to the reduced interactions of the per-oxo-like species formed and the oxygen released from Li2MnO3 with solvents in ethylene carbonate-methyl-ethyl carbonate/LiPF6 solutions. Our TEM studies revealed that typically, upon initial cycling both at 0 degrees c and 30 degrees c, Li2MnO3 underwent partial structural layered-to-spinel (Li2Mn2O4) transition.

关键词： lithium-ion batteries Li and Mn-rich materials Li2MnO3 activation at 0 ° c stabilized cycling decreased the voltage hysteresis layered-to-spinel transition bulk and surface characteristics

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Synthesis, characterization and control of Proportion of Polymorph c in ITQ-16 and ITQ-17 Films

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chemical Research in chinese Universities 2016年第6期32卷 895-901页

作者： cHEN Yanli FENG Lai College of Physics Optoelectronics and Enevgy Soochow University Suzhou 215006 P. R. China School of Materials Science and Engineering Tianjin University of Technology Tianjin 300384 P. R. China

continuous ITQ-16 and ITQ-17 films on silicon wafer were prepared in fluoride media using TEAOH asorganic structure-directing agent. The proportion ofpolymorph c in the as-synthesized ITQ-16 and ITQ-17 films wasdetermined via X-ray diffraction characterization. The proportion of polymorph c in the ITQ-16 and 1TQ-17 filmswas controlled via optimizing the compositions of the reaction mixtures and reaction conditions, such as varyingthe Si/Ge molar ratio and adding n-propyl alcohol as a solvent in the reaction mixture, The Ge atoms in the reactionmedia strongly increased the crystallization of polymorph c in ITQ-16 and ITQ-17 films. Moreover, the stabilizingand buffering effect of n-propyl alcohol on crystal growth further enhanced the proportion of polymorph c in theITQ-16 and ITQ-17 films. For potential catalytic applications, A1 was incorporated into the framework ofpolymorphc, and a pure phase of polymorph c in Al-ITQ-17 film was achieved from the synthesis gel in the n-propyl alcohol phase.

关键词： Zeolite beta ITQ-16 ITQ-17 Polymorph c

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Effect of c/N ration on disposal of pig carcass by co-composting with swine manure: experiment at laboratory scale

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ENVIRONMENTAL TEcHNOLOGY 2021年第28期42卷 4415-4425页

作者： chen, Yan Li, Xiaoyu Li, Shuying Xu, Yongping Dalian Univ Technol Sch Bioengn Dalian 116024 Liaoning Peoples R China Minist Educ Ctr Food Safety Anim Origin Dalian 116620 Peoples R China Dalian SEM Bioengn Technol Co Ltd Dalian 116620 Peoples R China

Disposal of animal carcasses by co-composting with animal waste usually selected conventional carbon to nitrogen (c/N) ratio around 25:1, in which the compost is widely used throughout the world. In this study, the pig carcass tissue blocks were sampled for composting at a laboratory scale to evaluate the effect of c/N ratio on the pig carcass compost. The time of thermophilic phase between 60 degrees c - 70 degrees c at a lower c/N ratio of 20:1 was significantly longer than that at the conventional c/N ratio, and it was the only one with the temperature beyond 70 degrees c that lasted for 2 days. Germination index and T value (the final c/N ratio / the initial c/N ratio) of the treatment with a c/N ratio of 20:1 were 94.67% and 0.69, respectively, meeting the standards of animal carcass compost. The degradation rate was 75.67%, and no significant difference was obtained as compared to the conventional c/N ratio groups. Organic fertilizer produced from the treatment with a c/N ratio of 20:1 was selected to evaluate the fertility by pot experiment of cayenne pepper compared with chemical fertilizer. The results showed that organic fertilizer from this treatment could significantly improve the growth of cayenne pepper. Overall, the use of the lower c/N ratio of 20:1 in the disposal of pig carcass by co-composting with swine manure could achieve the similar degradation rate as well as the maturity and stability of organic fertilizer as compared with the traditional c/N ratio at lab scale.

关键词： Disposal of pig carcass co-composting c N ratio degradation rate organic fertilizer

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