An efficient and low-divergence method for generating inhomogeneous and anisotropic turbulence with arbitrary spectra

In this article, we propose a divergence-free method for the generation of inhomogeneous and anisotropic turbulence. Based on the idea of correlation reconstruction, the method uses the Cholesky decomposition matrix to re-establish the turbulence correlation functions, which avoids the time-consuming procedure that solves eigenvalues and eigenvectors in every location needed by the coordinate transformation in the conventional method and thus reduces the computational complexity and improves the efficiency of generating synthetic turbulence. Through adjusting the generation strategy of specific random vectors, the proposed method, which is based on the classical spectrum-based method widely used to generate uniform isotropic turbulence, can obtain inhomogeneous and anisotropic turbulence with a relatively low divergence level in practice with almost no additional computational burden. There are two versions of this new method: the shifter version and the inverter version. Both versions of the method are highly efficient, easy to implement, and compatible with high-performance computing. Suitable for providing high-quality initial or boundary conditions for scale-resolving turbulence simulations with large grid numbers (such as direct numerical simulation or large eddy simulation), this method can be quickly implemented either based on various open-source CFD codes or common commercial CFD software

Peridynamic modeling of mode-I delamination growth in double cantilever composite beam test: a two-dimensional modeling using revised energy-based failure criteria

This study presents a two-dimensional ordinary state-based peridynamic (OSB PD) modeling of mode-I delamination growth in a double cantilever composite beam (DCB) test using revised energy-based failure criteria. The two-dimensional OSB PD composite model for DCB modeling is obtained by reformulating the previous OSB PD lamina model in x–z direction. The revised energy-based failure criteria are derived following the approach of establishing the relationship between critical bond breakage work and energy release rate. Loading increment convergence analysis and grid spacing influence study are conducted to investigate the reliability of the present modeling. The peridynamic (PD) modeling load–displacement curve and delamination growth process are then quantitatively compared with experimental results obtained from standard tests of composite DCB samples, which show good agreement between the modeling results and experimental results. The PD modeling delamination growth process damage contours are also illustrated. Finally, the influence of the revised energy-based failure criteria is investigated. The results show that the revised energy-based failure criteria improve the accuracy of the PD delamination modeling of DCB test significantly

Observation of an in-plane magnetic-field-driven phase transition in a quantum Hall system with SU(4) symmetry

In condensed matter physics, the study of electronic states with SU(N) symmetry has attracted considerable and growing attention in recent years, as systems with such a symmetry can often have a spontaneous symmetry-breaking effect giving rise to a novel ground state. For example, pseudospin quantum Hall ferromagnet of broken SU(2) symmetry has been realized by bringing two Landau levels close to degeneracy in a bilayer quantum Hall system. In the past several years, the exploration of collective states in other multi-component quantum Hall systems has emerged. Here we show the conventional pseudospin quantum Hall ferromagnetic states with broken SU(2) symmetry collapsed rapidly into an unexpected state with broken SU(4) symmetry, by in-plane magnetic field in a two-subband GaAs/AlGaAs two-dimensional electron system at filling factor around $\nu=4$. Within a narrow tilting range angle of 0.5 degrees, the activation energy increases as much as 12 K. While the origin of this puzzling observation remains to be exploited, we discuss the possibility of a long-sought pairing state of electrons with a four-fold degeneracy.Comment: 13 pages, 4 figure

Nifedipine promotes the proliferation and migration of breast cancer cells

Nifedipine is widely used as a calcium channel blocker (CCB) to treat angina and hypertension,but it is controversial with respect the risk of stimulation of cancers. In this study, we demonstrated that nifedipine promoted the proliferation and migration of breast cancer cells both invivo and invitro. However, verapamil, another calcium channel blocker, didn’t exert the similar effects. Nifedipine and high concentration KCl failed to alter the [Ca2+]i in MDA-MB-231 cells, suggesting that such nifedipine effect was not related with calcium channel. Moreover, nifedipine decreased miRNA-524-5p, resulting in the up-regulation of brain protein I3 (BRI3). Erk pathway was consequently activated and led to the proliferation and migration of breast cancer cells. Silencing BRI3 reversed the promoting effect of nifedipine on the breast cancer. In a summary, nifedipine stimulated the proliferation and migration of breast cancer cells via the axis of miRNA-524-5p-BRI3–Erk pathway independently of its calcium channel-blocking activity. Our findings highlight that nifedipine but not verapamil is conducive for breast cancer growth and metastasis, urging that the caution should be taken in clinic to prescribe nifedipine to women who suffering both hypertension and breast cancer, and hypertension with a tendency in breast cancers

Characteristics of the Tan-Lu Strike-Slip Fault and Its Controls on Hydrocarbon Accumulation in the Liaodong Bay Sub-Basin, Bohai Bay Basin, China

The Tan-Lu Fault, one of the major strike-slip structures in China, controlled the development of most of the Meso-Cenozoic NNE trend rifted petroliferous basins in east China. It has cut across the Bohai Bay Basin since the late Cenozoic and played an important role in hydrocarbon accumulation and distribution in the Liaodong Bay sub-basin of the Bohai Bay Basin. The purpose of this paper is to study the geometry of the Tan-Lu strike-slip and how it affected petroleum system development in the Liaodong Bay sub-basin. The innovative seismic interpretation revealed the western branch of the Tan-Lu strike-slip fault cut through the Liaozhong depression of the sub-basin and its eastern branch superimposed on the earlier extensional boundary fault of the sub-basin. The strike-slip movement is characterized by a distinctive strike-slip zone associated with the NE en echelon faults in the central part of the Liaozhong depression and also caused the formation of the Liaodong uplift and the Liaodong depression in the east Liaodong Bay Sub-basin. Rapid movement of the Tan-Lu strike-slip fault has deepened the Liaozhong depression and facilitated the maturation of source rock. Related fault movement formed a series of structural traps and paleotopographic highs and lows that subsequently controlled sediment dispersal and the distribution of stratigraphic-related traps within sequence stratigraphic framework. Exploration practice, geochemical study and petroleum system modeling demonstrate that the Tan-Lu strike-slip and its associated faults acted as good hydrocarbon migration pathways and hydrocarbon accumulated in many traps associated with the Tan-Lu strike-slip zone. Many recent discoveries along the strike-slip zone prove that the petroleum system in Liaodong Bay Sub-basin was mainly controlled by the activity of the Tan-Lu strike-slip. The resulting hydrocarbon accumulation model in this sub-basin may provide a paradigm for the prediction of hydrocarbon accumulation to other east China basins along the Tan-Lu strike-slip fault zone. Key words: Liaodong Bay Sub-basin; Tan-Lu strike-slip fault; Hydrocarbon accumulation; Petroleum system; Sequence stratigraph