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Cambrian explosion fossils from the North China craton

National Science Review 2022年第7期9卷 13-13页

作者： jean-Bernard caron Department of Natural History Royal Ontario Museum

Our understanding of the Cambrian explosion has relied heavily on a few exceptional fossil deposits preserving soft-bodied animals,the so-called Burgess-Shale-type deposits,or BSTs for *** are named after the famous Canadian fossil deposit discovered by Charles Walcott in *** ofwhere they come from or their age,all BSTs preserve soft-bodied fossils as carbonaceous remains.

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TAPHONOMY AND COMMUNITY OF THE EARLY CAMBRIAN CHENGJIANG LAGERSTTTE FROM THE MAFANG SECTION, SW CHINA

TAPHONOMY AND COMMUNITY OF THE EARLY CAMBRIAN CHENGJIANG LAG...

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第二届国际古生物学大会

作者： jean-Bernard caron Department of Natural History Royal Ontario Museum100 Queen’s Park Toronto Ontario

Reconstruction of a fossil community is generally biased by time-averaging of fossil records in the sedimentary rocks. However, the rapid event layers with extraordinarily preserved soft-bodied fossils in the fossil-lagerstatte such as the Chengjiang Lagerstatte provide an opportunity to investigate the relationships between temporal community patterns and environmental changes.

关键词： Chengjiang Lagersatte taphomony palaeoecology early Cambrian

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Positioning Temperature Sensors for Frost Protection in Northern Cranberry Production

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Agricultural Sciences 2017年第9期8卷 960-971页

作者： Vincent Pelletier Silvio Jose Gumiere Steeve Pepin Jacques Gallichand jean caron Département des Sols et de Génie Agroalimentaire Université Laval Québec Canada

Frost can cause serious economic losses in cranberry fields, particularly in northern regions. When the air temperature reaches a low critical threshold, sprinklers are operated to protect vines, to insure crop production and profitability. To avoid frost injury, proper positioning of temperature sensors is critical. A field experiment was designed and conducted to determine the optimal installation height of sensors above soil surface. Temperature data was used to investigate the spatial temperature gradient in the section of a cranberry field. A computer simulation of the temperature profile was performed to simulate the effect of wind velocity on the prediction of air temperature. For optimal use, sensors should be installed at the height of the canopy and several meters away from a dike. On nights with low wind velocities, the canopy air temperature was 2.7°C below that of 500 cm above the ground. The sensors should be put at least five m away from a dike to avoid the transfer of heat from the dike to the sensor. Also, multiple sensors should be installed because of the large variations in air temperature that were measured across the experiment. The simulated temperature indicated that wind velocity strongly influenced the temperature estimation;the effect of the wind on temperatures gradients was greater when the wind velocity was low (<2.3 m/s).

关键词： Frost Protection Cranberry Production Numerical Simulation of Heat Transfer

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Numerical Investigation by the Finite Difference Method of the Laser Hardening Process Applied to AISI-4340

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Journal of Applied Mathematics and Physics 2018年第10期6卷 2087-2106页

作者： Rachid Fakir Noureddine Barka jean Brousseau Gabriel caron-Guillemette Département de mathématiques informatique et génie Université du Québec à Rimouski 300 Allée des Ursulines Rimouski QC Canada Bombardier Transport Canada Inc. La Pocatière Québec Canada

This paper presents a numerical and experimental analysis study of the temperature distribution in a cylindrical specimen heat treated by laser and quenched in ambient temperature. The cylinder studied is made of AISI-4340 steel and has a diameter of 14.5-mm and a length of 50-mm. The temperature distribution is discretized by using a three-dimensional numerical finite difference method. The temperature gradient of the transformation of the microstructure is generated by a laser source Nd-YAG 3.0-kW manipulated using a robotic arm programmed to control the movements of the laser source in space and in time. The experimental measurement of surface temperature and air temperature in the vicinity of the specimen allows us to determine the values of the absorption coefficient and the coefficient of heat transfer by convection, which are essential data for a precise numerical prediction of the case depth. Despite an unsteady dynamic regime at the level of convective and radiation heat losses, the analysis of the averaged results of the temperature sensors shows a consistency with the results of microhardness measurements. The feasibility and effectiveness of the proposed approach lead to an accurate and reliable mathematical model able to predict the temperature distribution in a cylindrical workpiece heat treated by laser.

关键词： Laser Hardening Scanning Speed Case Depth Finite Difference Method AISI-4340

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Use of a new retrograde filling material(Biodentine) for endodontic surgery: two case reports

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International Journal of Oral Science 2014年第4期6卷 250-253页

作者： Grégory caron jean Azérad Marie-Odile Faure Pierre Machtou Yves Boucher Private practice Dental School Paris Diderot University Dental Service Pitié Salpêtrière Hospital Septodont Saint-Maur-des-Fosses

Mineral trioxide aggregate（MTA） is considered at the present time as the gold standard for root-end filling in endodontic ***, this biocompatible material presents several drawbacks such as a long setting time and handling difficulties. The aim of this article is to present a new commercialized calcium silicate-based material named Biodentine with physical improved properties compared to MTA in a clinical application. Two endodontic microsurgeries were performed by using specific armamentarium（microsurgical instrumentation, ultrasonic tips） under high-power magnification with an operatory microscope. Biodentine was used as a root-end filling in order to seal the root canal system. The two cases were considered completely healed at 1 year and were followed for one more year. The 2-year follow-up consolidated the previous observation with absence of clinical symptoms and radiographic evidence of regeneration of the periapical tissues.

关键词： Biodentin endodontics healing periapical surgery retrograde filling

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