Mechanical Behavior of Shale Rock under Uniaxial Cyclic Loading and Unloading Condition

In order to investigate the mechanical behavior of shale rock under cyclic loading and unloading condition, two kinds of incremental cyclic loading tests were conducted. Based on the result of the short-term uniaxial incremental cyclic loading test, the permanent residual strain, modulus, and damage evolution were analyzed firstly. Results showed that the relationship between the residual strains and the cycle number can be expressed by an exponential function. The deformation modulus E50 and elastic modulus ES first increased and then decreased with the peak stress under the loading condition, and both of them increased approximately linearly with the peak stress under the unloading condition. On the basis of the energy dissipation, the damage variables showed an exponential increasing with the strain at peak stress. The creep behavior of the shale rock was also analyzed. Results showed that there are obvious instantaneous strain, decay creep, and steady creep under each stress level and the specimen appears the accelerated creep stage under the 4th stress of 51.16 MPa. Based on the characteristics of the Burgers creep model, a viscoelastic-plastic creep model was proposed through viscoplastic mechanics, which agrees very well with the experimental results and can better describe the creep behavior of shale rock better than the Burgers creep model. Results can provide some mechanics reference evidence for shale gas development

Potassium-chemical synthesis of 3D graphene from CO2 and its excellent performance in HTM-free perovskite solar cells

The conversion of greenhouse gas CO2 into novel materials is the most promising approach to solve greenhouse gas issues. Herein, we report for the first time the reaction of potassium with CO2 to synthesize three-dimensional honeycomb-like structured graphene (3DHG). Furthermore, 3DHG exhibited excellent performance as a counter electrode for hole transport material (HTM)-free perovskite solar cells, leading to a power conversion efficiency of 10.06%. This work constitutes a new aspect of potassium chemistry for material synthesis from a greenhouse gas and the generation of electrical energy from sunlight.Fil: Wei, Wei. Michigan Technological University; Estados UnidosFil: Hu, Baoyun. Tongji University; ChinaFil: Jin, Fangming. Shanghai Jiao Tong University; ChinaFil: Jing, Zhenzi. Tongji University; ChinaFil: Li, Yuexiang. Nanchang University; ChinaFil: Garcia Blanco, Andres Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada ; ArgentinaFil: Stacchiola, Dario Jose. Brookhaven National Laboratory; Estados UnidosFil: Hu, Yun Hang. Michigan Technological University; Estados Unido

Triethyl­ammonium (indane-1,2,3-trione 1,2-dioximato-κ2 N 1,O 2)(indane-1,2,3-trione 2-oximato 1-oxime-κ2 N 1,O 2)nickel(II)

In the title compound, (C6H16N)[Ni(C9H4N2O3)(C9H5N2O3)], the NiIIion is four-coordinated by two N atoms and two O atoms from two indane-1,2,3-trione-1,2-dioxime ligands. The two organic ligands are linked by an intra­molecular O—H⋯O hydrogen bond. In the crystal, mol­ecules are linked by N—H⋯O hydrogen-bonds