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Instrumented and Vickers Indentation for the Characterization of stiffness,Hardness and Toughness of Zirconia Toughened Al_2O_3 and SiC Armor

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Journal of Materials Science & Technology 2015年第8期31卷 773-783页

作者： Aleksandra Nastic Ali Merati Mariusz Bielawski Manon bolduc Olaniyi Fakolujo Michel Nganbe Department of Mechanical Engineering University of Ottawa National Research Council Canada Defence R&D Canada(DRDC Valcartier)

Instrumented and Vickers indentation testing and microstructure analysis were used to investigate zirconia toughened alumina （ZTA） and silicon carbide （SIC）. Several equations were studied to relate the Vickers indentation hardness, Young＇s modulus and crack behavior to the fracture toughness. The frac- ture in SiC is unstable and occurs primarily by cleavage leading to a relatively low toughness of 3 MPa m1/2, which may be inappropriate for multi-hit capability. ZTA absorbs energy by plastic deformation, pore collapse, crack deviation and crack bridging and exhibits time dependent creep. With a relatively high toughness around 6.6 MPa m1/2, ZTA is promising for multi-hit capability. The higher accuracy of median equations in calculating the indentation fracture toughness and the relatively high c/a ratios above 2.5 suggest median type cracking for both SiC and ZTA. The Young＇s modulus of both ceramics was most accurately measured at lower indentation loads of about 0.5 kgf, while more accurate hardness and fracture toughness values were obtained at intermediate and at higher indentation loads beyond 5 kgf, respectively. A strong indentation size effect （ISE） was observed in both materials. The load independent hardness of SiC is 2563 HV, putting it far above the standard armor hardness requirement of 1500 HV that is barely met by ZTA.

关键词： Zirconia toughened alumina Silicon carbide Armor Vickers indentation fracture toughness Elastic modulus Vickers hardness

Survey of recent advances of in the field of π-conjugated heterocyclic azomethines as materials with tuneable properties

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Science China Chemistry 2013年第1期56卷 3-23页

作者： bolduc Andréanne MALLET Charlotte SKENE W. G. Laboratoire de Caractérisation Photophysique des Matériaux Conjugués Département de ChimieUniversité de MontréalCP 6128Centre-villeMontrealQC H3C 3J7Canada

This account gives an overview of our recent work in the area of conjugated azomethines derived from *** will be presented that mild reaction conditions can be used to selectively prepare symmetric and unsymmetric conjugated *** further will be demonstrated that azomethines consisting of various 5-membered aryl heterocycles lead to chemically,reductively,hydrolytically,and oxidatively robust *** optical and electrochemical properties of these materials can be tuned contingent on the degree of conjugation,type of aryl heterocycle,and by including various electronic *** end result is materials having colors spanning 250 nm across the visible *** colors further can be tuned via electrochemical or chemical *** resulting doped states have high color contrasts from their corresponding neutral *** collective opto-electronic properties and the means to readily tune them,make thiophenoazomethine derivatives interesting materials for potential use in a gamut of applications.

关键词：调谐特性甲亚胺芳杂环材料共轭电化学性能反应条件使用选择

All inkjet-printed perovskite-based bolometers

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npj Flexible Electronics 2020年第1期4卷 297-301页

作者： Charles Trudeau Patrick Beaupré Martin bolduc Sylvain G.Cloutier Department of Electrical Engineering École de Technologie SupérieureMontréalCanada Institut National d’Optique Québec QuébecCanada Department of Mechanical Engineering Universitédu QuébecàTrois-RivièresTrois-RivièresCanada

We show flexible bolometer devices produced entirely using digital inkjet printing on polymer *** bolometers consist of a silver interdigital electrode thermistor covered with a methylammonium lead trihalide perovskite absorber layer which shows good absorber characteristics at visible *** the standalone thermistor and the complete bolometer devices show polymer PTC thermistor-like behavior over a temperature range of 17 to 36℃,with a change in resistance up-to six orders of magnitude over this temperature *** addition of the perovskite absorber to the thermistor structure provides the illumination-dependent behavior proper to bolometers.

关键词： absorber perovskite illumination

Role of Microstructural Features in Toughness Improvement of Zirconia Toughened Alumina

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Journal of Minerals and Materials Characterization and Engineering 2016年第1期4卷 87-102页

作者： Olaniyi Fakolujo Ali Merati Mariusz Bielawski Manon bolduc Michel Nganbe University of Ottawa Ottawa Canada National Research Council Canada NRC Aerospace Ottawa Canada Defence R&D Canada (DRDC Valcartier) Quebec Canada

Ceramics constitute an integral part of highly efficient armours due to their low density, high hardness, strength and stiffness. However, they lack toughness and multi-hit capability. Therefore, zirconia toughened alumina is investigated. The hardness is evaluated using Vickers, Knoop and instrumented indentations, while the fracture toughness is evaluated using the indentation technique and Charpy tests. The strength is evaluated using ring-on-ring, four point bend and drop weight tests. The Young’s modulus is evaluated using the unloading instrumented indentation curves. Microstructure, porosity and density are characterised using ultrasonic scanning, Archimedes principle, optical and scanning electron microscopy. Results show an indentation size effect on all mechanical properties. A substantial improvement in toughness is achieved through retardation of crack initiation by tetragonal-to-monoclinic phase transformation in zirconia particles, crack deviation thanks to appropriate grain structure, as well as energy absorption by densification due to remaining porosity. This improved toughness is expected to promote multi-hit capability.

关键词： Zirconia Toughened Alumina Toughening Mechanisms Fracture Toughness Ballistic Performance and Multi-Hit Capability

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应用酶学法选择抗寒小麦品种

麦类作物学报 1984年第4期 8-10页

作者： R.bolduc 苏祖芳

利用预先结合到细胞膜上的酸性磷酸酯酶溶解能力的动态测定来估计结冰对植物细胞引起的损害。这些酶是按化学作用与细胞膜结合的蛋白质。酶和一部分内脂的结合与加进Tri—ton X—100的促使体外酶的激活作用和增溶作用一样,在同一条件下... 详细信息

利用预先结合到细胞膜上的酸性磷酸酯酶溶解能力的动态测定来估计结冰对植物细胞引起的损害。这些酶是按化学作用与细胞膜结合的蛋白质。酶和一部分内脂的结合与加进Tri—ton X—100的促使体外酶的激活作用和增溶作用一样,在同一条件下,都受到12(烷)基磺酸钠的抑制。这就表明:这种酶是同细胞膜结合的

关键词：小麦品种摄氏温度对数值指数函数酸性磷酸脂酶鲜重初等函数抗寒锻炼麦类麦类作物

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不典型睡眠结构和自闭症表型

世界核心医学期刊文摘（神经病学分册） 2005年第9期1卷 27-28页

作者： Limoges E. Mottron L. bolduc C. R. Godbout 方伯言 Sleep Laboratory Hopital Riviere-des-Prairies 7070 Perras Blvd. Montreal Que. H1E 1A4 Canada Dr.

A growing body of evidence indicates that people with autism frequently experi ence sleep disorders and exhibit atypical sleep architecture. In order to establ ish whether sleep disorders truly belong to the autism spectrum disorder (ASD) p henotype, we conducted a subjective and objective study of sleep in a group of h igh-functioning adults with ASD but without sleep complaints, psychiatric disor ders or neurological comorbidity. We compared the subjective data of 27 ASD part icipants with those of 78 healthy controls matched for chronological age and gen der. Subjective measures of sleep in the clinical group were compatible with ins omnia and/or a tolerable phase advance of the sleep-wake cycle. Subjective data were confirmed by objective laboratory sleep recordings in a subset of 16 patie nts and 16 controls. Persons with autism presented with a longer sleep latency ( P stage 1 sleep (P stages 2 +3+4, P stages 3 +4, P stage 2 EEG sleep spindles (P state anxiety scores of the Spiel berger scale and cortisol levels were the same in the two groups. Objective tota l sleep time correlated negatively with the Social (-0.52, P stic Interview-Revised. T he sleep of clinical subgroups (10 with high-functioning autism, six with Asper ger syndrome) did not differ, except for the presence of fewer EEG sleep spindle s in the Asperger syndrome subgroup (P < 0.05). In conclusion, these findi

关键词：自闭症睡眠结构睡眠梭形波睡眠障碍睡眠潜伏期慢波睡眠快速动眼睡眠睡眠研究神经系统疾病睡眠-觉醒周期

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中国市场决定奔驰新S未来

产品可靠性报告 2013年第6期32卷 10-10页

作者： Douglas A. bolduc 贾江伟

5月15日，戴姆勒在汉堡正式向世界发布第十代梅赛德斯一奔驰S级新车，不过在我看来，或许在上海首秀这款车会更合适，原因是2010年至2012年，奔驰S级在全球范围内共计销售了超过181000辆，但其在中国市场的销量已经占到全球销量的49％！

关键词：中国市场奔驰市场决定梅赛德斯戴姆勒销量新车汉堡