Compressing glassy carbon above 40 GPa, we have observed a new carbon allotrope with a fully sp(3)-bonded amorphous structure and diamondlike strength. Synchrotron x-ray Raman spectroscopy revealed a continuous pressure-induced sp(2)-to-sp(3) bonding change, while x-ray diffraction confirmed the perseverance of noncrystallinity. The transition was reversible upon releasing pressure. Used as an ...

Damage in a rock mass is heavily dependent on the existence and growth of joints, which are also influenced by complex stress states induced human activities (e.g., tunneling excavation). A proper representation loading path essential for understanding mechanical behaviors masses. Based discrete element method (DEM), influence cracking process specimen containing an open flaw examined. The effe...

String representations of the SU(N)-version of compact QED in three and four dimensions are constructed. Using for concreteness the three-dimensional case, it is demonstrated how the resulting SU(N)-generalization of the so-called theory of confining strings can be obtained in various ways. Such an SU(N)-theory of confining strings is then compared with the approach to the derivation of the str...

The potential of three heavy quarks has recently been the object of detailed numerical studies [1,2], which lend support to the so-called Y law, inspired by a string picture of heavy baryons. Here, we study the leading effect of string fluctuations on the potential, the analogue of the Lüscher term [3,4,5] in the quark-antiquark potential. Understanding such corrections to the Y law is particul...

Monopolonium is a monopole-antimonopole bound state, whose lifetime grows as the cube of the initial diameter. Such objects are important because their decay products can be observable. Apart from the monopolonium, it is believed that the existence of an epoch when the U(1) of the electromagnetism is spontaneously broken ensures the efficient annihilation of monopoles and antimonopoles in the U...

Understanding deep rocks' mechanical properties and failure evolution is crucial for efficient resource development. This study investigates the of tight sandstone analyzes its acoustic emission (AE) characteristics using a combined discrete element model moment tensor inversion. The AE activity during loading categorized into three stages: crack initiation, stable propagation, unstable propaga...

Electron backscatter diffraction (EBSD) was used to determine the orientation of mechanically twinned grains in Carrara marble experimentally deformed a small strain (?4%) at room temperature and moderate confining pressure (225 MPa). The thicknesses deformation twins were mostly too permit determination their by EBSD but it proved possible measure orientations calculating twin from host grain ...

The filling of thin-walled steel tubes with quartz sand can help to prevent the premature buckling of the steel tube at a low cost. During an impact, the internal stress of the quartz sand-filled steel tube column is subjected to not only axial force but also lateral confining force, resulting in complicated internal stress. A suitable sensor for monitoring the internal stress of such a structu...