检索结果-南通市图书馆

fatigue resistance of ProTaper gold exposed to high-concentration sodium hypochlorite in double curvature artificial canal

在线全文

学校读者我要写书评

暂无评论

Bioactive Materials 2019年第1期4卷 245-248页

作者： Fahda Algahtani Xiangya Huang Markus Haapasalo Zhejun Wang Ahmed Hieawy Duo Zhang Jolanta Aleksejuniene Ya Shen Department of Oral Biological and Medical Sciences Faculty of DentistryThe University of British ColumbiaVancouverCanada College of Dentistry Princess Nourah Bint Abdulrahman UniversitySaudi Arabia Department of Conservative Dentistry and Endodontics Guanghua School of StomatologySun Yat-Sen UniversityGuangzhouChina

This study aimed to evaluate and compare the fatigue resistance of ProTaper Gold(PTG)and ProTaper Universal(PTU)in artificial single and double curvature canals in 5%sodium hypochlorite(NaOCl)at body temperature(37℃).PTG and PTU files(size F1)were subjected to fatigue tests in two different artificial ceramic *** single curvature model had a 60°curvature angle with a 5mm *** double curvature model had a 60°curvature angle with a 5mm radius and a second 30°curvature with a 2mm radius.A file segment was introduced into the artificial canal and immersed in water or 5%NaOCl at 37℃.The total number of cycles to fracture(NCF)was *** were analyzed using t-test and linear regression *** NCF of all files was significantly influenced by the type of NiTi metal alloy(Pfatigue resistance than PTU files in both single and double curvature canals(Pfatigue performance of PTG is better than that of PTU in both single and double *** conditions may affect the fatigue behavior of PTU files with single curvature.

关键词： Body temperature Corrosion Double curvature fatigue resistance ProTaper Gold

A dissipated energy comparison to evaluate fatigue resistance using 2-point bending

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2014年第1期1卷 49-54页

作者： Cinzia Maggiore Gordon Airey Paul Marsac NTEC University of NottinghamNottinghamUnited Kingdom IFSTTAR NantesFrance

fatigue is the main failure mode in pavement engineering. Typically, micro-cracks originate at the bottom of asphalt concrete layer due to horizontal tensile strains. Micro-cracks start to propagate towards the upper layers under repeated loading which can lead to pavement failure. Different methods are usually used to describe fatigue behavior in asphalt materials such as： phenomenological approach, fracture mechanics approach and dissipated energy ap- proach. This paper presents a comparison of fatigue resistances calculated for different dissipated energy models using 2-point bending （2PB） at IFSTTAR in Nantes. 2PB tests have been undertaken under different loading and environmental conditions in order to evaluate the properties of the mixtures （stiffness, dissipated energy, fatigue life and healing effect）.

关键词： fatigue resistance dissipated energy 2-point bending fracture mechanics approach

A preliminary study on the anti-inflammatory and analgesic effects of two extracts of pine pollen on anoxia and fatigue resistance

在线全文

学校读者我要写书评

暂无评论

TMR Aging 2020年第2期2卷 59-66页

作者： Shi-Bo Zhao Suo-Yi Huang Yu-Xin Wei Zhong-Gang Wu Han-Jun Ma Xue-Ying Yu Hui-Man Yang Yi-Jie Wang Yu-Zhu Zeng College of Clinical Medicine Youjiang Medical University For NationalitiesBaise 533000China College of Pharmacy Youjiang Medical University for NationalitiesBaise 533000China Key Laboratory of Guangxi's College for the Study of Characteristic Medicine in Youjiang River Basin Youjiang Medical University for NationalitiesBaise 533000China College of Basic Medicine Youjiang Medical University for NationalitiesBaise 533000China College of Medical Imaging Youjiang Medical University for NationalitiesBaise 533000China

Background:To study the anti-inflammatory,analgesic,fatigue resistant and antihypoxia effects of ethanol extract and water extract of pine ***:Two different extracts of pine pollen were prepared into there different concentrations,that is 1.5 mg·mL^-1,4.5 mg·mL^-1 and 7.5 mg·mL^-1 *** extract were studied by xylene-induced ear swelling,acetic acid distortion test and hot plate *** antihypoxia and antifatigue effects were explored by weight-bearing swimming experiment,routine pressure hypoxia tolerance experiment and liver weight coefficient ***:Through the study of the four pharmacological effects of ethanol extract and water extract,we found that the anti-inflammatory,analgesic,antithyposia and antifatigue effects of ethanol extract were better than that of water ***,the experimental effects significantly improved with the increase of the concentration,and the effect of alcohol increased dose group was accurate(P<0.05).Conclusion:Pine pollen has excellent effects of anti-inflammatory,analgesic,antihypoxia and ***,with the increase of drug concentration,effects tend to be more obvious with positive correlation.

关键词： Pine pollen Alcohol extract Water extract Anti-inflammatory effect Analgesic effect Antihypoxia fatigue resistance

Ionic conductive hydrogels toughened by latex particles for strain sensors

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2021年第4期64卷 827-835页

作者： CHANG JingYu ZHANG ZhiXin JIA Fei GAO GuangHui Polymeric and Soft Materials L aboratory School of Chemical Engineering and Advanced Institute of Materials ScienceChangchun University of TechnologyChangchun 130012China

Conductive hydrogels have attracted tremendous attention due to their excellent softness and stretchability as wearable strain sensing ***,most of hydrogel-based strain sensors suffered from poor self-recoverability and fatigue resistance,resulting in significant decrease of strain sensitivity after ***,a soft and flexible wearable strain sensor is prepared by using an ionic conductive hydrogel with latex particles as physical cross-linking *** dynamic physical cross-linking structure can effectively dissipate energy through disruption and reconstruction of molecular segments,thereby imparting excellent stretchability,self-recoverability and fatigue *** addition,the hydrogel exhibits excellent strain-sensitive resistance changes,which enables it to be assembled as a wearable sensor to monitor human *** a result,the hydrogel strain sensor can provide precise feedback for a wide range of human activities,including large-scale joint bending and tiny ***,the tough ionic conductive hydrogel would be widely applied in electronic skin,medical monitoring and artificial intelligence.

关键词： ionic conductive hydrogel strain sensor self-recovery fatigue resistance

The Influence of Trans-1,4-poly(butadiene-co-isoprene) Copolymer Rubbers(TBIR) with Different Molecular Weights on the NR/TBIR Blends

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2019年第10期37卷 966-973,I0003页

作者： Hao Wang Ri-Guo Wang Yun-Sheng Ma Bo Luan Ai-Hua He Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-plastics(Ministry of Education)School of Polymer Science and EngineeringQingdao University of Science and TechnologyQingdao 266042China Shandong Huaju Polymer Material Co. Ltd.Binzhou 256500China

The molecular weight of a polymer is of prime importance and greatly influences the processing and mechanical properties of the polymer. Trans-1,4-poly(butadiene-co-isoprene) multi-block copolymer rubbers(TBIR) exhibit outstanding fatigue resistance, low heat build-up and good abrasion resistance, and are expected to be desirable candidate for high performance tire. Study on the influence of TBIR with different molecular weights on the structure and properties of TBIR and natural rubber(NR)/TBIR blends is essential to understand its contribution to the greatly improved dynamic properties of the rubber vulcanizates. TBIR with different molecular weights characterized by 1H-NMR, 13C-NMR, GPC, and DSC were highly trans-1,4-copolymers with similar chain sequence distribution and crystalline trans-1,4-polyisoprene(TPI) blocks. The green strength and modulus of TBIR increased with the increasing molecular *** NR/TBIR compounds filled with 40 phr carbon black were chemically cured by sulfur for the preparation of NR/TBIR *** compatibility between NR and TBIR, filler distribution, crosslinking bond and density, and properties of NR/TBIR vulcanizates were studied. The NR/TBIR vulcanizates showed increasing tensile strength, hardness, modulus, rebound, abrasion resistance, and flexural fatigue properties with increasing molecular weight of TBIR. Furthermore, they presented significant improvement in flexural fatigue resistance when compared with that of NR vulcanizate. The contribution mechanism of TBIR on the NR/TBIR blends was discussed. The TBIR with a wide range of molecular weight are ideal rubbers for high performance tires.

关键词： Trans-1,4-poly(butadiene-co-isoprene)copolymer rubber Nature rubber Blends Molecular weight fatigue resistance

SYNTHESIS AND PHOTOCHROMISM OF ACRYLIC ESTER COPOLYMERS BEARING PENDANT VIOLOGEN GROUPS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 1996年第3期14卷 248-254页

作者：孙学慧杨玉昆 Institute of Chemistry Academia Sinica Beijing 100080

A series of acrylic ester copolymers with viologen group as pendant were synthesizedthrough the reaction of MMA-EBA (Ethenyl bromoacetate) copolymer with 4-(4'-pyridyl)-N-alkyl (or arylalkyl) pyridiniums. These viologen copolymers can exchange their anionwith NH_4PF_6 in methanol to improve their solubility in organic solvents such as DMFand acetone. Compared with the corresponding low molecular viologens, these viologencopolymers have relatively lower color development rate under UV light and fade fasterin air due to less affinity to photo-reductant and deficiency of association between theircation radicals. Their photofatigue resistant ability is also slightly better than that of lowmolecular vinlogens.

关键词： Viologen copolymer Photochromism Fading rate fatigue resistance

Large electric field-induced strain in the novel BNKTAN-BNBLTZ lead-free ceramics

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第10期42卷 15-22页

作者： Chao Wang Qiang Li Weiming Zhang Huiqing Fan State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China

(1-x)Bi0.5(Na0.82K0.18)0.5Ti0.96(Al0.5Nb0.5)0.04O3-xBi0.46Na0.46Ba0.5La0.02Ti0.97Zr0.03O3 lead-free ceramics(abbreviated as BNKTAN-100x BNBLTZ)was prepared by the conventional solid *** patterns and EDS spectrums revealed that a stable solid solution had been formed between BNBLTZ and *** the introduction of BNBLTZ anti-ferroelectric content,BNKTAN relaxor ferroelectrics exhibited the excellent field-induced-strain for x=0.04 corresponding to electric field-induced strain S^0.505%and normal strain d33*~777 pm/V at 65 kV/*** large strain response was attributed to the emergence of PNRs in the relaxation ***,an excellent fatigue resistance performance was obtained within 105cycles(S=0.505%–0.495%and d33*=777–758 pm/V,65 kV/cm).It suggested that prepared ceramics had the great potential to strain sensor and actuators.

关键词： BNT-based ceramics Ferroelectric properties Strain fatigue resistance

Rheological Evaluation of Polymer Modified Asphalt Binders

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2015年第4期30卷 695-702页

作者：王岚常春清 School of Civil Engineering Inner Mongolia University of Technology

The microstructure and dynamic rheological characteristics of asphalt containing different polymer modifiers （crumb rubber, styrene-butadiene-styrene and crumb rubber mix with styrene- butadiene-styrene） at mid and high service temperature levels were investigated by using scanning electron microscopy（SEM）, dynamic shear rheometer（DSR） and repeat creep test. The main objective of the investigation was to rank the modifiers based on their effect on performance characteristics of asphalt under service conditions. To evaluate the effect of different modifiers on the viscoelastic response of asphalt, the temperature and frequency dependences of the dynamic viscoelastic properties were compared. The mid-temperature fatigue resistance and high-temperature rutting resistance of three polymer modified asphalts were evaluated to predict their field performance in roads. Based on the current results, an improved rutting factor was proposed to determine the rutting resistance of asphalt pavements. In addition, the viscous stiffness （Gv）, defined as the reciprocal of viscous compliance, was used to evaluate the high-temperature deformation resistance of asphalt mixtures. The experimental results indicate that the asphalt containing crumb rubber only shows superior performance at mid and high service temperatures in all three modified asphalt binders due to the action of the crumb rubber.

关键词： polymer modified asphalt rheological properties fatigue resistance rutting resistance

Thermal shock fatigue behavior of TiC/Al_2O_3 composite ceramics

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2008年第3期27卷 308-314页

作者： SI Tingzhi LIU Ning ZHANG Qing＇ an YOU Xianqing School of Materials Science and Engineering Anhui University of Technolog3 Ma ＇anshan 243002 China School of Materials Science and Engineering Hefei University＇ of Technology Hefei 230009 China

The thermal shock fatigue behaviors of pure hot-pressed alumina and 30 wt.% TiC/Al2O3 composites were studied. The effect of TiC and Al2O3 starting particle size on the mechanical properties of the composites was discussed. Indentation-quench test was conducted to evaluate the effect of thermal fatigue temperature difference （ΔT） and number of thermal cycles （Ⅳ） on fatigue crack growth （Δa）. The mechanical properties and thermal fatigue resistance of TiC/Al203 composites are remarkably improved by the addition of TiC. The thermal shock fatigue of monolithic alumina and TiC/Al2O3 composites is due to a ＂true＂ cycling effect （thermal fatigue）. Crack deflection and bridging are the predominant reasons for the improvement of thermal shock fatigue resistance of the composites.

关键词： ceramic matrix composites TiC/Al2O3 composites thermal shock fatigue fatigue behavior fatigue resistance