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81.
The transformation of SiO2 from low pressure tetrahedral phases into denser octahedral phases takes place via the collapse of the oxygen sublattice into a close-packed arrangement. The transition paths and the resulting products are known to be affected by the presence of anisotropic stresses, which are difficult to control, so interpretation of the experimental results is problematic. Based on nonhydrostatic molecular dynamics simulations, we show that the collapse of the oxygen sublattice in the specific case of cristobalite is concomitant with the disappearance of tetrahedral units and that non hydrostatic stresses can be tuned to yield phases with different oxygen close-packed sublattices, including the alpha-PbO2-like phase, for which we provide a microscopic formation path, and phases with a cubic close packing, like anatase, not seen in experiments yet. 相似文献
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84.
Indranil Roy Dinesh Shetty Raghunandan Hota Kangkyun Baek Jeesu Kim Chulhong Kim Sandro Kappert Kimoon Kim 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(50):15367-15370
Developing a material that can combat antibiotic‐resistant bacteria, a major global health threat, is an urgent requirement. To tackle this challenge, we synthesized a multifunctional subphthalocyanine (SubPc) polymer nanosphere that has the ability to target, label, and photoinactivate antibiotic‐resistant bacteria in a single treatment with more than 99 % efficiency, even with a dose as low as 4.2 J cm−2 and a loading concentration of 10 nM . The positively charged nanosphere shell composed of covalently linked SubPc units can increase the local concentration of photosensitizers at therapeutic sites. The nanosphere shows superior performance compared to corresponding monomers presumably because of their enhanced water dispersibility, higher efficiency of singlet‐oxygen generation, and phototoxicity. In addition, this material is useful in fluorescence labeling of living cells and shows promise in photoacoustic imaging of bacteria in vivo. 相似文献
85.
Summary This paper proposes expressions of the dynamic pressure and of the transfer functions (response factors) between the dynamic pressure amplitude and the wave amplitude and between the dynamic pressure and the vertical displacement of the wave profile, for irrotational progressive gravity waves to third order approximation (non-linear theory).Some characteristic behaviours of the dynamic pressure and of the response factors are examined and compared with those of waves to first order approximation (linear theory).
相似文献
Sommario Si ricavano le espressioni della pressione dinamica per onde irrotazionali progressive di gravità al terzo ordine di approssimazione (modello non lineare).Si individuano le funzioni di trasferimento (fattori di risposta) sia tra l'ampiezza della pressione dinamica e l'ampiezza d'onda, sia tra la pressione dinamica e lo spostamento verticale della superficie di ondulazione.Si esaminano comportamenti caratteristici della pressione dinamica e dei fattori di risposta e si confrontano tali comportamenti con quelli relativi alle onde al primo ordine di approssimazione (modello lineare).
相似文献
86.
Carlos E.D. NazarioAmanda S. Santana Cristiane Y. KawasokoCarlos A. Carollo Gabriela R. HurtadoLuiz H. Viana Sandro L. BarbosaPalimécio G. Guerrero Jr. Francisco A. MarquesVânia B. Dabdoub Miguel J. DabdoubAdriano C.M. Baroni 《Tetrahedron letters》2011,52(32):4177-4181
Sonogashira cross-coupling reactions involving (E)-iodo vinyl stannanes and terminal acetylenes were carried out in the presence of Pd(PPh3)4, CuI and several amines, affording (Z)-tributylstannyl enynes in moderate to good yields (62-91%). Utilizing the catalytic system containing Pd(PPh3)4 (5%), CuI (10%), and TBAOH (40% in aqueous media) as activator, better yields (72-91%) and lower reaction times were achieved. 相似文献
87.
We define the Wodzicki Residue TR(A) for A belonging to a space of operators with double order, denoted \({L^{m_1,m_2}_{\rm cl}}\). Such operators are globally defined initially on \({\mathbb{R}^n}\) and then, more generally, on a class of non-compact manifolds, namely, the manifolds with cylindrical ends. The definition is based on the analysis of the associate zeta function ζ(A, z). Using this approach, under suitable ellipticity assumptions, we also compute a two terms leading part of the Weyl formula for a positive selfadjoint operator \({A\in L^{m_1,m_2}_{\rm cl}}\) in the case m 1 = m 2. 相似文献
88.
Marini A Macchi S Jurinovich S Catalano D Mennucci B 《The journal of physical chemistry. A》2011,115(35):10035-10044
In this study we combined QM calculations and NMR measurements to understand at a detailed level the complex interplay of structural/electronic properties with the effects of the solvent in the NLO activity of push-pull systems, quantified in terms of variations of the static hyperpolarizability. Different parameters (bond lengths and bond length alternation, vibrational frequencies, electronic charge distribution) are introduced and tested to rationalize both the solvent sensitivity of three molecular systems (namely, p-nitroaniline, ethyl 4-ammino benzoate, and 5-nitro-1H-indole) and the differences among them. This analysis has finally allowed us to establish a clear correlation between the charge transfer behavior of the systems, their NLO properties, and NMR parameters also validating simplified but effective chemical analyses based on resonance limit forms. 相似文献
89.
Silicates are one of the most important classes of compounds on this planet, and more than 1000 silicates have been identified in the mineral kingdom. Additionally, several hundreds of artificial silicates have been synthesized. The substitution of oxygen by nitrogen leads to the structurally diverse and manifold class of nitridosilicates. Silicon nitride, one of the most important non-oxidic ceramic materials, is the binary parent compound of nitridosilicates, and it symbolizes the inherent material properties of these refractory compounds. However, prior to the last decades, a broad systematic investigation of nitridosilicates had not been accomplished. In the meantime, these and related compounds have reached a remarkable level of industrial application. This review illustrates recent progress in synthesis and structure-property relationships and also applications of nitridosilicates, oxonitridosilicates, and related SiAlONs. 相似文献
90.