Effect of a Shock Pulse on a Floating Ice Sheet

The vibrations of a viscoelastic plate lying on an elastic liquid base subjected to pulse loading have been studied theoretically and experimentally. The effect of the variable depth of the reservoir, plate thickness, and strain relaxation time on the value of the plate vibration amplitude and the length and curvature of the flexural gravity wave profile are analyzed. Good agreement of theoretical and experimental results is obtained.     

瞬态温度场作用下冰载荷计算

给出了关于冰的粘弹性微分本构模型的广义变分原理和冰载荷计算的有限元方法。修正的增量粘弹性矩阵有效地加速了迭代过程,计算了瞬态温度场下冰内压应力分布及对结构物作用力。其结果与实测数据定性吻合。     

斜面结构冰荷载的动荷效应

利用改进的刚性梁模型进行了斜面结构冰荷载的动荷效应,推导了冰力的动荷系统,算例得到了与模型试验值和数值解相近的结果,依据分析对试验观察到的规律给出了理论上的证明和定性的解释,给出了准静态冰力条件的判别式。     

New behaviors of α-particle preformation factors near doubly magic 100Sn

The begin{document}$ alpha $end{document}-particle preformation factors of nuclei above doubly magic nuclei begin{document}$ ^{100} $end{document}Sn and begin{document}$ ^{208} $end{document}Pb are investigated within the generalized liquid drop model. The results show that the begin{document}$ alpha $end{document}-particle preformation factors of nuclei near self-conjugate doubly magic begin{document}$ ^{100} $end{document}Sn are significantly larger than those of analogous nuclei just above begin{document}$ ^{208} $end{document}Pb, and they will be enhanced as the nuclei move towards the begin{document}$ N = Z $end{document} line. The proton–neutron correlation energy begin{document}$ E_{p-n} $end{document} and two protons–two neutrons correlation energy begin{document}$ E_{2p-2n} $end{document} of nuclei near begin{document}$ ^{100} $end{document}Sn also exhibit a similar situation, indicating that the interactions between protons and neutrons occupying similar single-particle orbitals could enhance the begin{document}$ alpha $end{document}-particle preformation factors and result in superallowed begin{document}$ alpha $end{document} decay. This also provides evidence of the significant role of the proton–neutron interaction on begin{document}$ alpha $end{document}-particle preformation. Also, the linear relationship between begin{document}$ alpha $end{document}-particle preformation factors and the product of valence protons and valence neutrons for nuclei around begin{document}$ ^{208} $end{document}Pb is broken in the begin{document}$ ^{100} $end{document}Sn region because the begin{document}$ alpha $end{document}-particle preformation factor is enhanced when a nucleus near begin{document}$ ^{100} $end{document}Sn moves towards the begin{document}$ N = Z $end{document} line. Furthermore, the calculated begin{document}$ alpha $end{document} decay half-lives fit well with the experimental data, including the recent observed self-conjugate nuclei begin{document}$ ^{104} $end{document}Te and begin{document}$ ^{108} $end{document}Xe [Phys. Rev. Lett. 121, 182501 (2018)].     

Mimicking the Ice Recrystallization Activity of Biological Antifreezes. When is a New Polymer “Active”?

Antifreeze proteins and ice‐binding proteins have been discovered in a diverse range of extremophiles and have the ability to modulate the growth and formation of ice crystals. Considering the importance of cryoscience across transport, biomedicine, and climate science, there is significant interest in developing synthetic macromolecular mimics of antifreeze proteins, in particular to reproduce their property of ice recrystallization inhibition (IRI). This activity is a continuum rather than an “on/off” property and there may be multiple molecular mechanisms which give rise to differences in this observable property; the limiting concentrations for ice growth vary by more than a thousand between an antifreeze glycoprotein and poly(vinyl alcohol), for example. The aim of this article is to provide a concise comparison of a range of natural and synthetic materials that are known to have IRI, thus providing a guide to see if a new synthetic mimic is active or not, including emerging materials which are comparatively weak compared to antifreeze proteins, but may have technological importance. The link between activity and the mechanisms involving either ice binding or amphiphilicity is discussed and known materials assigned into classes based on this.