Yanshan University

About: Yanshan University is a education organization based out in Qinhuangdao, China. It is known for research contribution in the topics: Microstructure & Control theory. The organization has 19544 authors who have published 16904 publications receiving 184378 citations. The organization is also known as: Yānshān dàxué.

Protective effects of two Lactobacillus plantarum strains in hyperlipidemic mice

Abstract: Core tip: Protective effects of Lactobacillus plantarum (L. plantarum) CAI6 and L. plantarum SC4 strains on hyperlipidemic mice were found, including regulating lipid metabolism, alleviating hepatic steatosis and reducing cardiovascular disease (CVD) risk. The mechanism of intracorporal antioxidation of Lactobacillus strains may be related to stimulation of nuclear factor-erythroid 2-related factor 2 (Nrf2) expression. Hypolipidemic effect and Nrf2-induced antioxidative defense may contribute to the reduction of CVD risk. We suggest that food fermented by the strains be used as part of the diet to relieve lipid metabolism related metabolic syndrome and to reduce the risk of CVD.

Strength, hardness, and lattice vibrations of Z -carbon and W -carbon: First-principles calculations

Abstract: The strength, hardness, and lattice vibrations of two superhard carbon allotropies, $Z$-carbon and $W$-carbon are investigated by first-principles calculations. Phonon dispersion calculations indicate that $Z$-carbon and $W$-carbon are dynamically stable at least up to 300 GPa. The strength calculations reveal that the failure mode in $Z$-carbon is dominated by the tensile type, and the [010] direction is the weakest one. In $W$-carbon, the failure mode is dominated by the shear type, and the (101)[$11\overline{1}$] direction is the weakest one. Although the ideal strength of diamond is distinctly greater than that of $Z$-carbon and $W$-carbon, the tensile strength and shear strength for Z-carbon and $W$-carbon show much lower anisotropies than that of diamond. The hardness calculations indicate that the average hardness of $Z$-carbon is less than that of diamond but greater than that of the $W$-carbon, $M$-carbon, and body-centered-tetragonal-C${}_{4}$ carbon. The simulated Raman spectra show that the ${A}_{g}$ modes at 1094 cm${}^{\ensuremath{-}1}$ for $Z$-carbon and 1109.7 cm${}^{\ensuremath{-}1}$ for $W$-carbon are in agreement with that of 1082 cm${}^{\ensuremath{-}1}$ observed in the experiment of cold-compressed graphite at 9.8 GPa.

MAS-Based Distributed Cooperative Control for DC Microgrid Through Switching Topology Communication Network With Time-Varying Delays

Abstract: A multiagent system based distributed cooperative control is proposed for a dc microgrid. First, the multiagent system based control scheme is built, where each distributed energy resource unit is associated with a first-level unit control agent to deal with primary control and a secondary-level distributed cooperative control agents to implement secondary control. For the secondary control purposes of global voltage regulation and proportional current sharing, both voltage and current regulators are installed in each secondary-level agent. Their consensus secondary control protocols are designed by using the state information exchanged among only adjacent secondary-level control agents based on a switching topology communication network with time-vary delays. Then these protocols are applied into the associated first-level agent to structure an improved outer-loop droop controller. According to the reference set points corrected by the improved droop controller, an inner-loop voltage/current robust controller is designed in place of the conventional PI control to regulate the voltage and current of distributed energy resource unit. Finally, the validity of the proposed control is testified by means of simulation results.

Effect of cyclic heat treatments on spheroidizing behavior of cementite in high carbon steel

Abstract: The spheroidizing behavior of cementite in Fe–0.8C mass% steel during cyclic heat treatment was investigated. The effect of cyclic numbers on the microstructure and mechanical properties of the experimental steel was discussed. In the present work, each cyclic heat treatment consisted of a short-duration (5 min) held at 1043 K (above A1 temperature 1003 K) and a short-duration (3 min) held at 953 K. The spheroidizing ratio of cementite and the average size of particles grow with the increase of cyclic numbers. After five cyclic heat treatments, the cementite spheroidizes completely, the average size of cementite particles is about 0.49 μm and the larger particles ratio is below 4%. After cyclic heat treatment, the plasticity of the experimental steel clearly increases. The elongation of the as-transformed specimen is about 8%, the elongation of the 1-cycle specimen is 25.4%, and the elongation of the 5-cycle specimen reaches a peak value of 33.9%. The ultimate tensile strength (UTS) of as-transformed specimens is about 680 MPa, and the UTS of the 1-cycle specimen decreases to about 620 MPa; however, the UTS of the 3-cycle specimen increases to about 650 MPa. The ratio of yield strength to tensile strength is about 0.70 after cyclic heat treatments.