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排序方式: 共有199条查询结果,搜索用时 15 毫秒
1.
The stress-strain relations and the yield behavior of a model glass (a 80:20 binary Lennard-Jones mixture) is studied by means of molecular dynamics simulations. In a previous paper it was shown that, at temperatures below the glass transition temperature, Tg, the model exhibits shear banding under imposed shear. It was also suggested that this behavior is closely related to the existence of a (static) yield stress (under applied stress, the system does not flow until the stress sigma exceeds a threshold value sigmay). A thorough analysis of the static yield stress is presented via simulations under imposed stress. Furthermore, using steady shear simulations, the effect of physical aging, shear rate and temperature on the stress-strain relation is investigated. In particular, we find that the stress at the yield point (the "peak"-value of the stress-strain curve) exhibits a logarithmic dependence both on the imposed shear rate and on the "age" of the system in qualitative agreement with experiments on amorphous polymers, and on metallic glasses. In addition to the very observation of the yield stress which is an important feature seen in experiments on complex systems like pastes, dense colloidal suspensions and foams, further links between our model and soft glassy materials are found. An example is the existence of hysteresis loops in the system response to a varying imposed stress. Finally, we measure the static yield stress for our model and study its dependence on temperature. We find that for temperatures far below the mode coupling critical temperature of the model (Tc = 0.435 in Lennard-Jones units), sigmay decreases slowly upon heating followed by a stronger decrease as Tc is approached. We discuss the reliability of results on the static yield stress and give a criterion for its validity in terms of the time scales relevant to the problem. 相似文献
2.
Bocquet ML Michaelides A Loffreda D Sautet P Alavi A King DA 《Journal of the American Chemical Society》2003,125(19):5620-5621
Reaction mechanisms and activation energies for the complete conversion of ethene to ethene epoxide on two recently characterized oxidized Ag{111} surfaces have been determined from density functional theory. On both surfaces, epoxidation proceeds through a two-step nonconcerted mechanism via an oxametallacycle intermediate. The key implications are that both surfaces are active and that epoxidation can take place over a wide O coverage regime. 相似文献
3.
Lesaicherre ML Lue RY Chen GY Zhu Q Yao SQ 《Journal of the American Chemical Society》2002,124(30):8768-8769
We report here the first example using an intein-mediated expression system to generate biotinylated proteins suitable for immobilization onto avidin-functionalized glass slides. With this novel array, proteins are site-specifically immobilized on the glass surface and are able to retain their native activity. The advantage of the avidin/biotin linkage over his-tag/Ni-NTA strategies for protein immobilization is highlighted by its ability to withstand a variety of chemical conditions, which makes this new protein array compatible with most biological assays. 相似文献
4.
K. Sistemich W. -D. Lauppe T. A. Khan H. Lawin H. A. Selič J. P. Bocquet E. Monnand F. Schussler 《Zeitschrift für Physik A Hadrons and Nuclei》1978,285(3):305-313
Nuclear spectroscopy studies of 51 133 Sb82 have been performed at the recoil fission product separators JOSEF and LOHENGRIN. A tentative level scheme has been established for this nucleus with one proton in addition to the doubly closed shell core132Sn. Two isomeric states with half-lives of 3 and 16 μs have been found at excitation energies of >4300 keV and 4526 keV, respectively. Lower limits of 15/2 are deduced for the spins of these levels. The h11/2 proton state is suggested at 2792 keV in agreement with the systematics of the lighter Z=51 isotopes and the heavier N=82 isotones. Several states have been observed between 4300 and 4600 keV which are probably due to the coupling of the single proton to core-excited states which have energies between 4000 and 4800 keV. 相似文献
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J. P. Bocquet F. Malek H. Nifenecker M. Rey-Campagnolle M. Maurel E. Monnand P. Perrin C. Ristori G. Ericsson T. Johansson G. Tibell S. Polikanov T. Krogulski J. Mougey 《Zeitschrift für Physik A Hadrons and Nuclei》1992,342(2):183-189
Antiproton induced fission probabilities of U238, Bi209, Pb208 and Au177 are reported together with the mass distribution of the fission fragments in the U238 and Bi209 cases. The charged particles multiplicities observed in co-incidence with fission have, also, been measured for U and Bi and are presented.Dedicated to Peter Armbruster on the occasion of his 60th birthday in recognition of his important contribution to modern Nuclear Physics 相似文献
9.
K. Sistemich W. -D. Lauppe H. Lawin F. Schussler J. P. Bocquet E. Monnand J. Blomqvist 《Zeitschrift für Physik A Hadrons and Nuclei》1979,292(2):145-151
A new isomeric state witht 1/2=3.9±0.3μs has been observed in the nucleus 52 132 Te80 which has two protons more and two neutrons less than the doubly magic isobar 50 132 Sn82. The deexcitation pattern suggests spin and parity 10+ for this level near 2,700 keV which is populated in fission. The energy and the half-life of the isomer can be understood with the assumption that it is the 10+ level based on theh 11 2/?2 neutron hole configuration. 相似文献
10.
Mathilde Briday Franois Hall Lauriane Lecoq Sylvie Radix Juliette Martin Roland Montserret Marie Dujardin Marie-Laure Fogeron Michael Nassal Beat H. Meier Thierry Lomberget Anja Bckmann 《Chemical science》2022,13(30):8840
Hepatitis B virus (HBV) is a small enveloped retrotranscribing DNA virus and an important human pathogen. Its capsid-forming core protein (Cp) features a hydrophobic pocket proposed to be central notably in capsid envelopment. Indeed, mutations in and around this pocket can profoundly modulate, and even abolish, secretion of enveloped virions. We have recently shown that Triton X-100, a detergent used during Cp purification, binds to the hydrophobic pocket with micromolar affinity. We here performed pharmacomodulation of pocket binders through systematic modifications of the three distinct chemical moieties composing the Triton X-100 molecule. Using NMR and ITC, we found that the flat aromatic moiety is essential for binding, while the number of atoms of the aliphatic chain modulates binding affinity. The hydrophilic tail, in contrast, is highly tolerant to changes in both length and type. Our data provide essential information for designing a new class of HBV antivirals targeting capsid–envelope interactions.Small-molecule binding to the Hepatitis B virus core protein hydrophobic pocket, a possible strategy for targeting viral particle assembly. 相似文献