On the eigenvalues of a specially rank-r updated complex matrix

AbstractIn this paper, an alternatively simpler proof to an eigenvalue theorem of a specially structured rank-r updated complex matrix is presented and also its characteristic polynomial is explicitly determined by Leverrier’s algorithm for m–D system

The reverse order law for the weighted least square g-inverse of multiple matrix products

By using the ranks of the generalized Schur complement, the equivalent conditions for reverse order laws of the $\{1, 3M\}-$ and the $\{1, 4N\}-$ inverses of the multiple product of matrices are derived

Effect of holding temperature and time on ferrite formation in dual phase steel produced by strip casting

Conventional dual phase (DP) steel (0.08C-0.81Si-1.47Mn-0.03Al, wt. %) was manufactured by the laboratory simulation of strip casting. The effect of holding temperature and time on microstructure evolution was studied using a quench-deformation dilatometer. Microstructures were observed using optical and scanning electron microscopy. The results showed that the nose temperature of ferrite phase field is around 650 °C. The kinetics of ferrite formation is fast within the first 100 s of holding at this temperature, and then formation of ferrite continues at a slower rate until it reaches the fraction corresponding to that defined by the lever rule. 70~80 % ferrite was obtained after holding at 650 °C for 100~900 s. Some Widmänstatten ferrite was also observed probably because of a large prior austenite grain size and quenching after holding. In addition, austenite-to-ferrite transformation kinetics is fitted well using Johnson-Mehl-Avrami equation. The Avrami exponent for ferrite formation was approximately 1 for both 650 and 670 °C holding temperatures, which means rapid ferrite transformation. It deduces that the ferrite formation obeys a linear growth behavior, which is associated with a decrease in amount of nucleation sites

Role of apolipoprotein O in autophagy via the p38 mitogen-activated protein kinase signaling pathway in myocardial infarction

Objective: To explore the role and possible mechanisms of action of apolipoprotein O (APOO) in autophagy in Myocardial Infarction (MI) in vivo and in vitro. Methods: Differential gene expression and single Gene Set Enrichment Analysis (GSEA) were used to evaluate MI-related candidate genes. Animal and cell MI models were established. Sh-APOO, si-APOO, and SB203580 were used to inhibit the expression of APOO or p38MAPK. Western blot and qRT-PCR were used to analyze the expression levels of the target protein or mRNA. Apoptosis was observed using the TUNEL assay. The plasma concentrations of CK-MB and cTn-I in humans and mice were determined. Results: In the GSE23294 dataset, APOO mRNA was highly expressed in the left ventricle of mice with MI; GSEA revealed that APOO was positively correlated with p38MAPK, autophagy, and apoptosis. The plasma concentration of APOO in patients with MI was significantly higher than that in healthy subjects. The expression of APOO, Beclin-1, LC3, and Bax in mouse and AC16 cell MI models increased, while the level of Bcl-2 decreased. After silencing the APOO gene, the expression of APOO was downregulated; meanwhile, changes in autophagy, apoptosis and myocardial cell injury were reversed in vivo and in vitro. Furthermore, autophagy was alleviated after AC16 cells were treated with SB203580. Conclusions: The increased APOO expression in mouse and cell MI models may activate autophagy and apoptosis by regulating the p38MAPK signaling pathway, thus aggravating the myocardial injury

Observation of deformation twinning and martensitic transformation during nanoindentation of a transformation-induced plasticity steel

For the first time, deformation twinning and martensitic transformation were observed in retained austenite in a low-Alloyed transformation-induced plasticity steel using nanoindentation in conjunction with electron backscattering diffraction and transmission electron microscopy. Dislocation glide, martensite formation and deformation twinning were correlated to pop-ins and deviation from linearity in the load-displacement curve. Deformation twinning was found to enhance the stability of retained austenite. This observation furthers our understanding of RA stability during straining of low-Alloyed multiphase TRIP steel

Effect of temperature on microstructure and deformation mechanism of Fe-30Mn-3Si-4Al TWIP steel at strain rate of 700 s-1

As twinning-induced plasticity (TWIP) steel is one potential material for shaped charge liner due to the combination of high strength and high plasticity, deformation mechanism at high strain rate and high temperature is required to study. Compression experiments of Fe-30Mn-3Si-4Al TWIP steel were conducted using a Gleeble-1500 thermal simulation machine and a split-Hopkinson pressure bar (SHPB) between 298 and 1073 K at strain rates of 10-3 and 700 s-1, respectively. Microstructures were observed using optical microscopy (OM) and transmission electron microscopy (TEM). Results show that flow stress and densities of deformation twins and dislocations decrease with increasing deformation temperature at strain rates of 10-3 and 700 s-1. The stack fault energy (SFE) values (Γ) of Fe-30Mn-3Si-4Al TWIP steel at different temperatures were calculated using thermodynamic data. Based on corresponding microstructures, it can be inferred that at 700 s-1, twinning is the main deformation mechanism at 298-573 K for 30 mJ/m2≤Γ≤63 mJ/m, while dislocation gliding is the main deformation mechanism above 1073 K for Γ≥ 145 mJ/m2. In addition, with increasing strain rate from 10-3 to 700 s-1, the SFE range of twinning is enlarged and the SEF value of twinning becomes higher

Optimizing the Coverage via the UAVs With Lower Costs for Information-Centric Internet of Things

The recent developments in the areas of the Internet of Things (IoTs) have provided a rapid growth in the epoch of the novel information-centric collections (IC-IoTs). In the IC-IoTs, expanding the ranges of information collections and reducing the costs are important issues for the information required platform. In the previous scenarios, the information is collected in a random manner, which leads to lower coverages and higher costs. Thus, a "optimizing the coverage via the unmanned aerial vehicles (UAVs) with lower costs for information-centric Internet of Things" (OCLC-IoTs) approach is established, which targets to improve the coverage ratio and to reduce the costs of the information-required platform via the cooperation of the information collectors and the UAVs. First, to improve the coverage ratio, an intensive strategy is proposed to inspire the information collectors to bid for the tasks published by the platform and an improved rolling horizon strategy (IRHS) strategy is designed to plan the flying routes of the UAVs to reach more coverage ranges. Then, to reduce the costs factor, the IRHS strategy is designed to shorten the flying routes of the UAVs under the prerequisite of guaranteeing coverage ratio to achieve fewers costs. Finally, a comprehensive theoretical analysis and experiments are provided, which indicates the advancements of the OCLC-IoTs scheme. Compared with the previous studies, the OCLC-IoTs scheme can improve the coverage ratio of information by 21.42% approximately and can reduce the cost ratio by 13.335% to 34.32%

An Efficient Method for Chip-Level Statistical Capacitance Extraction Considering Process Variations with Spatial Correlation

An efficient method is proposed to consider the process variations with spatial correlation, for chip-level capacitance extraction based on the window technique. In each window, an efficient technique of Hermite polynomial collocation (HPC) is presented to extract the statistical capacitance. The capacitance covariances between windows are then calculated to reflect the spatial correlation. The proposed method is practical for chip-level extraction task, and the experiments on full-path extraction exhibit its high accuracy and efficiency