An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Nanometer-scale crystals of the two-dimensional oxide molybdenum trioxide (MoO3) were formed atop the transition metal dichalcogenides MoS2 and MoSe2. The MoO3 nanocrystals are partially commensurate with the dichalcogenide substrates, being aligned only along one of the substrate's crystallographic axes. These nanocrystals can be slid only along the aligned direction and maintain their alignment with the substrate during motion. Using an AFM probe to oscillate the nanocrystals, it was found that the lateral force required to move them increased linearly with nanocrystal area. The slope of this curve, the interfacial shear strength, was significantly lower than for macroscale systems. It also depended strongly on the duration and the velocity of sliding of the crystal, suggesting a thermal activation model for the system. Finally, it was found that lower commensuration between the nanocrystal and the substrate increased the interfacial shear, a trend opposite that predicted theoretically.
A linear elastic body in plane strain which contains a stationary crack and which is initially at rest and stress free is considered. It is shown that if the elastodynamic displacement field and stress intensity factor are known, as functions of crack length, for any symmetrical distribution of time-varying forces which acts on the body, subsequent to t=0, then the stress intensity factor due to any other symmetrical load system whatsoever which acts on the same body may be directly determined. The other load system may be of arbitrary spatial distribution and time variation. Further, that part of the elastodynamic displacement field due to the other load system, which arises from the presence of the crack, may also be directly determined. The results are obtained by extension of Rice's mode of derivation of the corresponding Bueckner-Rice elastostatic results to Laplace-transformed elastodynamic variables. Likewise, the existence of a universal elastodynamic “weight function” for any given cracked body is demonstrated. As an application, Freund's recent result for the stress intensity factor due to suddenly applied concentrated forces on the crack surfaces is derived directly by our method, from de Hoop's earlier solution for suddenly applied uniform pressures.
No abstract is provided for this article.
Abstract Aus der Bildung von tert.‐Butylbenzol sowie 1,1‐Dimethyl‐ und 2,2‐Dimethyl‐ 2‐phenyl‐äthanol bei der Oxidation von Neophyllithium in n‐Pentan und n‐Hep tan (nicht in Gegenwart von z.B. Tetrahydrofuran) wird auf die intermediäre Bildung von Neophylradikalen geschlossen.
Scanning tunneling microscopy (STM) has been used to image 12- and 24-base pair (bp) synthetic oligonucleotide duplexes alone or with intercalatively-bound metal complexes with submolecular resolution. The sizes of the 12- and 24-bp oligonucleotides determined from STM images are close to expected values, and images of isolated duplexes resolve the two nucleotide strands of these molecules. The variation of duplex size in our images demonstrates that these features are not due to surface artifacts. In addition, images of the 12-bp duplex in the presence of bis(9,10-phenanthrenequinone diimine)(2,2'-bipyridyl)rhodium(III) exhibit a new structural feature at 14 +/- 2 A from the duplex ends. This new feature corresponds well to the metal binding site determined from DNA cleavage and molecular modeling studies. These results indicate that STM can be used to image directly transition metal complexes bound to DNA, and thus suggest that metal complexes bound specifically to biological molecules could serve as labels in STM structural studies.
