Dynamic Crack Propagating Mechanism of Rock Materials Based on Different Weighted Functions

The singularity at the crack tip can be smoothed by the non-local theory based on different types of weighted functions. In the paper, the characteristics of different types of the weighted functions and their effects on non-local model are analyzed. The effects of the stress intensity factor KI and KII on the all components of stress-strain field in the neighborhood of the crack tip are analyzed by different types of the weighted functions. It is shown that the larger intrinsic characteristic length scale is, the more significant the reduction of non-local strain with respect to the local strain predicted conventionally will be. The size of non-local strain field with the bell-shaped weighted functions is larger than that obtained by either Green's or Gaussian weighted functions. The non-local normal stress-strain components depends on the stress intensity factor KI and KII, the circumferential stress is related to the stress intensity factor KI. The effect of stress intensity factor KI on non-local radial stress is positive while the effect of KII is negative. The non-local circumferential stress is related only to the stress intensity factor KII while the non-local shear stress is related only to the stress intensity factor KI. The larger the intrinsic characteristic scale is, the more significant the reduction of non-local strain with respect to the local strain predicted conventionally will be

Delineating the molecular landscape of different histopathological growth patterns in colorectal cancer liver metastases

BackgroundHistopathological growth patterns (HGPs) have shown important prognostic values for patients with colorectal cancer liver metastases, but the potential molecular mechanisms remain largely unknown.MethodsWe performed an exploratory analysis by conducting the RNA sequencing of primary colorectal lesions, colorectal liver metastatic lesions and normal liver tissues.FindingsWe found that desmoplastic HGPs of the metastatic lesions were significantly enriched in EMT, angiogenesis, stroma, and immune signaling pathways, while replacement HGPs were enriched in metabolism, cell cycle, and DNA damage repair pathways. With the exception of immune-related genes, the differentially expressed genes of the two HGPs from colorectal liver metastases were mostly inherited from the primary tumor. Moreover, normal liver tissue in the desmoplastic HGP subgroup was markedly enriched in the fibrinous inflammation pathway.ConclusionsWe surmised that HGPs are observable morphological changes resulting from the regulation of molecular expressions, which is the combined effect of the heterogeneity and remodeling of primary tumors seeds and liver soils

Adjustable Robust Singular Value Decomposition: Design, Analysis and Application to Finance

The Singular Value Decomposition (SVD) is a fundamental algorithm used to understand the structure of data by providing insight into the relationship between the row and column factors. SVD aims to approximate a rectangular data matrix, given some rank restriction, especially lower rank approximation. In practical data analysis, however, outliers and missing values maybe exist that restrict the performance of SVD, because SVD is a least squares method that is sensitive to errors in the data matrix. This paper proposes a robust SVD algorithm by applying an adjustable robust estimator. Through adjusting the tuning parameter in the algorithm, the method can be both robust and efficient. Moreover, a sequential robust SVD algorithm is proposed in order to decrease the computation volume in sequential and streaming data. The advantages of the proposed algorithms are proved with a financial application

Adjustable Robust Singular Value Decomposition: Design, Analysis and Application to Finance

The Singular Value Decomposition (SVD) is a fundamental algorithm used to understand the structure of data by providing insight into the relationship between the row and column factors. SVD aims to approximate a rectangular data matrix, given some rank restriction, especially lower rank approximation. In practical data analysis, however, outliers and missing values maybe exist that restrict the performance of SVD, because SVD is a least squares method that is sensitive to errors in the data matrix. This paper proposes a robust SVD algorithm by applying an adjustable robust estimator. Through adjusting the tuning parameter in the algorithm, the method can be both robust and efficient. Moreover, a sequential robust SVD algorithm is proposed in order to decrease the computation volume in sequential and streaming data. The advantages of the proposed algorithms are proved with a financial application

Theoretical and numerical analysis on a thermo-elastic system with discontinuities

A second-order accurate numerical scheme is proposed for a thermo-elastic system which models a bar made of two distinct materials. The physical parameters involved may be discontinuous across the joint of the two materials, where there might be also singular heat and/or force sources. The solution components, the temperature and the displacement, may change rapidly across the joint. By transforming the system into a different one, time-marching schemes can be used for the new system which is well posed. The immersed interface method is employed to deal with the discontinuities of the coefficients and the singular sources. The proposed numerical method can fit both explicit and implicit formulation. For the implicit version, a stable and fast prediction-correction scheme is also developed. Convergence analysis shows that our method is second-order accurate at all grid points in spite of the discontinuities across the interface. Numerical experiments are performed to support the theoretical analysis in this paper

Research on the Stability of Open Financial System

We propose a new herd mechanism and embed it into an open financial market system, which allows traders to get in and out of the system based on some transition rates. Moreover, the novel mechanism can avoid the volatility disappearance when the population scale increases. There are three kinds of heterogeneous agents in the system: optimistic, pessimistic and fundamental. Interactions especially occur among three different groups of agents instead of two, which makes the artificial financial market more close to the real one. By the simulation results of this complex system, we can explain stylized facts like volatility clustering and find the key parameters of market bubbles and market collapses

Scheme Exploration and Performance Analysis of 800-Meter Superlarge Span Structure

Superlarge span structure is one of the important trends for future building development. Under the background of the 800-meter superlarge span dome project proposed by China Construction Group, this paper focuses on the structural optimization and performance analysis of this superlarge span structure. The previous ideas of the superdome and the maximum span of existed spatial structures are reviewed, and some structural form selection principles are put forward which lay foundation for structural selection. The applicability of high-strength steel and aluminum alloy is also discussed. It is demonstrated that the high-strength steel and aluminum alloy contribute little to structural comprehensive performances. Then, considering the effects of grid division, members topological relation, and surface shape, six kinds of rigid systems are contrastively studied to determine the optimal scheme. The structural performances along with the increasing span are explored in detail. To further reduce the structural weight and improve mechanical performance, a new composite scheme and the cable-stayed megastructure are proposed and studied. The research methods and performance analysis results can provide significant references for the following research on the superlarge span structure

Numerical approach for simulating the tensioning process of complex prestressed cable-net structures

The stability of cable-net structures depends on the prestress of the system. Due to the large displacement and mutual effect of the cables, it is difficult to simulate the tensioning process and control the forming accuracy. The Backward Algorithm (BA) has been used to simulate the tensioning process. The traditional BA involves complicated and tedious matrix operations. In this paper, a new numerical method based on the Vector Form Intrinsic Finite Element (VFIFE) method is proposed for BA application. Moreover, the tensioning sequence of a complex cable-net structure is introduced. Subsequently, a new approach for BA application in the simulation of the tensioning process is presented, which combines the VFIFE approach and the notion of form-finding. Finally, a numerical example is simulated in detail and the results of different tensioning stages are analyzed to verify the feasibility of the proposed approach. This study provides a significant reference for improving the construction control and forming accuracy of complex prestressed cable-net structures

The Preparation of Diaryl Sulfoxonium Triflates and Their Application in Palladium‐Catalyzed Cross‐Coupling Reactions

Treatment of N-methyl-S,S-diaryl sulfoximines with methyl trifluoromethanesulfonate provides bench-stable sulfoxinium salts in excellent yields. Applying them in Sonogashira-, Heck- and Suzuki-type cross-coupling reactions leads to the corresponding products by sequential C–S bond cleavage and C–C bond formation. Electronic factors induced by substituents on the S-aryl groups govern the coupling efficiency.peerReviewe