两院院士郑哲敏：爱国情怀是科学研究的重要动机

郑哲敏以光辉的一生，谱写了一首科技工作者不忘初心、牢记使命的壮丽诗篇，为中国力学事业留下了一座丰碑。2013年1月，北京人民大会堂。我国著名力学家、中国爆炸力学的奠基人和开拓者之一，中国科学院院士、中国工程院院士郑哲敏获颁2012年国家最高科学技术奖证书

トクベツ シエン ガッコウ ニ オケル スポーツ シドウ ノ イチコウサツ シガケン Ａコウ シドウシャ ノ シテキ カラ

学士（スポーツ学

A Computational Modelling of the Mechanical Performance of a Bioabsorbable Stent Undergoing Cyclic Loading

In order to address new challenges that arise in the degradation behavior of absorbable metal stents (AMSs) in vivo, new modelling and simulation are presented in this study. A dynamic corrosion model (Model 1) considering uniform corrosion, stress corrosion mechanisms and dynamic cyclic pulse loading was proposed to simulate the stent degradation based on Continuum Damage Mechanics (CDM). A control group (Model 2) was established which only considered the mechanisms of uniform and stress corrosion. The time of stent degraded completely in Model 1 was set as a normalized time unit (100t) to illustrate the results. With the increase of time, the mass and supporting performance of the stent decreased, especially at 10t to 20t. The average von Mises Stress of the stent in the Model 1 decreases from 86.19 MPa to 48.65 MPa roughly at 5t to15t, while the average von Mises Stress in Model 2 decreases from 87.12 MPa to 50 MPa. The mass loss ratio of stents in Model 1 is always higher than that in Model 2, and the relative error of the mass loss ratio reached 14.3% at 20t. The results showed that the corrosion occurs at first in the stent struts with the highest von Mises stress. In addition, the dynamic cyclic pulse loading accelerated the degradation rate and the supporting performance loss of stent. These modelling and simulation techniques may provide new insights to in vivo AMS performance. (C) 2019 The Authors. Published by Elsevier B.V

Effect of Plaque Composition on Biomechanical Performance of a Carotid Stent: Computational Study

Clinical application of bare metal stents is constrained by the occurrence of instent restenosis, mainly due to the complex biomechanical environment in the body. Numerical simulation method was used to evaluate the effect of plaque composition on stent performance in a carotid artery. CT angiography (CTA) data were used as a reference, and zero-load state of the carotid artery was used to establish a 3D stenotic artery model. Different plaque compositions, calcified and hypo-cellular were defined in Model 1 and Model 2, respectively. Interactions between the stents and arterial tissues within the stent crimping-expansion process were analyzed to explore the effects of plaque composition on the mechanical parameters of carotid stents. Goodman diagram and fatigue safety factor (FSF) were analyzed to explore the effects of plaque composition on fatigue performance of a carotid stent in the stent service process. In the stent crimping-expansion process, the von Mises stress in the stent and the dog-boning ratio in Model 1 were higher than that in Model 2. The calcified plaque prevented the stent from expanding the stenotic vessel to a pre-set diameter. Thus, the risk of rupture in the calcified plaque was higher than that in the hypo-cellular plaque. Plaque also affected the stress/strain in the vessel wall, which was observed to be lower in Model 1 than in Model 2. This indicated that calcified plaque could decrease the stress-induced injury of arterial tissues. Within the stent service process, the stents used in these two models were predicted to not fail under fatigue rupture as calculated by the Goodman diagram. Additionally, the points closer to the fatigue limit were generally observed at the inner bend of the stent crowns. The FSF of the stent in Model 1 was lower than that in Model 2. The stent operating in the presence of calcified plaques suffered high risk of fractures. Reliability and fatigue performance of the stent were found to be associated with plaque composition. Hence, this study may provide stent designers an approach toward enhancing the mechanical reliability of a stent

镀铁镍碳纤维的制备与厘米波干扰性能研究

FeNi-coated carbon fibers (CFs) are fabricated by electroless plating method to improve the attenuation properties in centimeter wave band. The structure and morphology of the coating is characterized by X-ray powder diffraction (XRD) and scanning electron micrography (SEM). TG-DTA thermal analysis is carried out to analyze the thermostability of the fibers. The vector network analyzer is used to obtain the attenuation performance in 2~18 GHz. The results show that the FeNi-coated carbon fibers are stable in the air at 500℃. The attenuation properties of FeNi/CFs are better than those of the pure CFs. The maximum reflection loss shifts to low frequency with the increase in the length of FeNi/CFs. The maximum absorption is -21.8 dB at 16 GHz and the bandwidth less than -10 dB is 13.2~18 GHz when the length of FeNi/CFs is 1 cm. A reflection loss exceeding -10 dB is found to exceed 9.5 GHz in the frequency range of 8.5~18 GHz for the mixtures with 1.5 cm and 1 cm in length. As a result, these FeNi/CFs may be used in broadband radar jamming applications. © 2015, China Ordnance Society. All right reserved

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^