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人造多晶冰抗压强度实验研究 总被引:1,自引:1,他引:1
对实验室制作的平均粒径为4mm的宏观各向同性粒状多晶冰,在冰温分别为-0.5、-2、-5和-10℃及应变率分别为4.2×10-4、5.5×10-5、5.5×10-6及3.5×10-7s-1下进行了单轴抗压强度实验。结果表明,极限抗压强度与负温和应变率的对数均呈正比例关系;在较高应变率下(4.2×10-4s-1),在-5℃时,出现韧脆性转折点。 相似文献
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m- or p-Iodinated, or brominated ω-phenoxyalcohols and phenols as well as halogenated indoles were subjected to halogen-magnesium exchange reactions with isopropyl magnesium bromide (iPrMgBr) or isopropyl magnesium di-n-butyl lithium ate complexes (iPrMgnBu2Li) at −78 °C to room temperature. iPrMgnBu2Li proved superior to prevent ortho-metallation of these substituted arenes. 相似文献
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Wei Yu Xiaomin Wu Yizhen Zhao Chun Chen Zhiwei Yang Xiaochun Zhang Jiayi Ren Yueming Wang Changwen Wu Chengming Li Rongfeng Chen Xiaoli Wang Weihong Zheng Huaxin Liao Xiaohui Yuan 《Molecules (Basel, Switzerland)》2021,26(23)
SARS-CoV-2 is highly homologous to SARS-CoV. To date, the main protease (Mpro) of SARS-CoV-2 is regarded as an important drug target for the treatment of Coronavirus Disease 2019 (COVID-19). Some experiments confirmed that several HIV protease inhibitors present the inhibitory effects on the replication of SARS-CoV-2 by inhibiting Mpro. However, the mechanism of action has still not been studied very clearly. In this work, the interaction mechanism of four HIV protease inhibitors Darunavir (DRV), Lopinavir (LPV), Nelfinavir (NFV), and Ritonavire (RTV) targeting SARS-CoV-2 Mpro was explored by applying docking, molecular dynamics (MD) simulations, and MM–GBSA methods using the broad-spectrum antiviral drug Ribavirin (RBV) as the negative and nonspecific control. Our results revealed that LPV, RTV, and NFV have higher binding affinities with Mpro, and they all interact with catalytic residues His41 and the other two key amino acids Met49 and Met165. Pharmacophore model analysis further revealed that the aromatic ring, hydrogen bond donor, and hydrophobic group are the essential infrastructure of Mpro inhibitors. Overall, this study applied computational simulation methods to study the interaction mechanism of HIV-1 protease inhibitors with SARS-CoV-2 Mpro, and the findings provide useful insights for the development of novel anti-SARS-CoV-2 agents for the treatment of COVID-19. 相似文献
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Feiyue Shi Jiayi Ma Jingwu Zhao Shengkang Liu 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(2):327-331
Neutron self-shielding effect in bulk materials impairs analysis of elements using prompt gamma-rays induced by thermal neutron capture reaction. For the on-line coal analysis setups of Nanjing Dalu Zhongdian Technology Joint-Stock Co., Ltd, Monte-Carlo simulations have been performed to investigate effect of the channel on correcting neutron self-shielding effect and improving measurement of H in coal. The results show that, by introducing an adequate channel in the moderator, the self-shielding effect can be corrected, and the linear concentration region of H can be extended effectively. 相似文献
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介绍了由5所高校联合研制,并列入面向21世纪课程教材出版规划的“电路多媒体CAI课件”的设计思想,主要内容和功能特点,探索在电路课程教学的各个环节中的现代化教学手段和教学方法的采用。 相似文献
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Xiaoming Gao Jiayi SunMing Hu Lijun WengFeng Zhou Weimin Liu 《Applied Surface Science》2011,257(17):7643-7648
Ag-Cu alloy film was deposited by arc ion plating (AIP). Atomic oxygen (AO) irradiation experiments were conducted using a ground AO simulation facility. The structure, morphology, composition and tribological property of the Ag-Cu alloy film before and after AO irradiation were investigated and compared with Ag film using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscope (XPS) and ball-on-disk tribometer, respectively. In depth XPS analysis clearly shows that the affected thickness of Ag-Cu alloy film was greatly reduced and the oxidation product was mainly Ag2O, but AgO and Ag2O in case of pure Ag film. As a result, the Ag-Cu alloy film exhibited better AO resistant behaviors, and showed a stable friction and low wear after the AO irradiation. The AO resistant behaviors of the Ag-Cu alloy film were discussed in terms of the film microstructure. 相似文献