Microstructure evolution of extruded Mg-Gd-Y magnesium alloy under dynamic compression

AbstractFor the purpose of investigating the microstructure evolution and deformation behavior of magnesium under high strain rates, the Split Hopkinson Pressure Bar (SHPB) apparatus was used under high strain rates from 755 s−1 to 2826 s−1 in the present work at room temperature. The microstructures of extruded Mg-Gd-Y Magnesium alloy under different strain rates and along different compression directions were observed by metallographic microscope. The results show that, microstructures of extruded Mg-Gd-Y Magnesium alloy along ED, TD and ND compression directions are sensitive to strain rates. The amount of twins firstly increases and then decreases with strain rates being increased, and the recrystal grains increase and grow up. When the strain rate reaches 2500 s−1, the adiabatic shear band (ASB) begins to form. The formation process of the adiabatic shear band can be divided into three stages. In the first stage, under the impact load a great deal of twins form and the deformation mechanism is twinning. In the second stage, discontinuous ASB forms due to twins adjusting the directions of located grains and the deformation mechanisms are twinning and non-basal slip. In the last stage, non-basal slip turns to basal slip and continuous ASB forms. The dynamic compression fracture mechanism of extruded Mg-Gd-Y Magnesium alloy is multi-crack propagation

Constructing disjoint Steiner trees in Sierpi\'{n}ski graphs

Let $G$ be a graph and $S\subseteq V(G)$ with $|S|\geq 2$. Then the trees $T_1, T_2, \cdots, T_\ell$ in $G$ are \emph{internally disjoint Steiner trees} connecting $S$ (or $S$-Steiner trees) if $E(T_i) \cap E(T_j )=\emptyset$ and $V(T_i)\cap V(T_j)=S$ for every pair of distinct integers $i,j$, $1 \leq i, j \leq \ell$. Similarly, if we only have the condition $E(T_i) \cap E(T_j )=\emptyset$ but without the condition $V(T_i)\cap V(T_j)=S$, then they are \emph{edge-disjoint Steiner trees}. The \emph{generalized $k$-connectivity}, denoted by $\kappa_k(G)$, of a graph $G$, is defined as $\kappa_k(G)=\min\{\kappa_G(S)|S \subseteq V(G) \ \textrm{and} \ |S|=k \}$, where $\kappa_G(S)$ is the maximum number of internally disjoint $S$-Steiner trees. The \emph{generalized local edge-connectivity} $\lambda_{G}(S)$ is the maximum number of edge-disjoint Steiner trees connecting $S$ in $G$. The {\it generalized $k$-edge-connectivity} $\lambda_k(G)$ of $G$ is defined as $\lambda_k(G)=\min\{\lambda_{G}(S)\,|\,S\subseteq V(G) \ and \ |S|=k\}$. These measures are generalizations of the concepts of connectivity and edge-connectivity, and they and can be used as measures of vulnerability of networks. It is, in general, difficult to compute these generalized connectivities. However, there are precise results for some special classes of graphs. In this paper, we obtain the exact value of $\lambda_{k}(S(n,\ell))$ for $3\leq k\leq \ell^n$, and the exact value of $\kappa_{k}(S(n,\ell))$ for $3\leq k\leq \ell$, where $S(n, \ell)$ is the Sierpi\'{n}ski graphs with order $\ell^n$. As a direct consequence, these graphs provide additional interesting examples when $\lambda_{k}(S(n,\ell))=\kappa_{k}(S(n,\ell))$. We also study the some network properties of Sierpi\'{n}ski graphs

Attenuation of Acute Lung Inflammation and Injury by Whole Body Cooling in a Rat Heatstroke Model

Whole body cooling is the current therapy of choice for heatstroke because the therapeutic agents are not available. In this study, we assessed the effects of whole body cooling on several indices of acute lung inflammation and injury which might occur during heatstroke. Anesthetized rats were randomized into the following groups and given (a) no treatment or (b) whole body cooling immediately after onset of heatstroke. As compared with the normothermic controls, the untreated heatstroke rats had higher levels of pleural exudates volume and polymorphonuclear cell numbers, lung myloperoxidase activity and inducible nitric oxide synthase expression, histologic lung injury score, and bronchoalveolar proinflammatory cytokines and glutamate, and PaCO2. In contrast, the values of mean arterial pressure, heart rate, PaO2, pH, and blood HCO3− were all significantly lower during heatstroke. The acute lung inflammation and injury and electrolyte imbalance that occurred during heatstroke were significantly reduced by whole body cooling. In conclusion, we identified heat-induced acute lung inflammation and injury and electrolyte imbalance could be ameliorated by whole body cooling

(Acetyl­acetonato-κ2 O,O′)bis­[2-(5-methyl-3-phenyl­pyrazin-2-yl-κN 1)phen­yl-κC 1]iridium(III)

In the title complex, [Ir(C17H13N2)2(C5H7O2)], the IrIII atom is hexa­coordinated in a distorted octa­hedral geometry by two C,N-bidentate 2-(5-methyl-3-phenyl­pyrazin-2-yl)phenyl (mdpp) ligands and one O,O-bidentate acetyl­acetonate ligand. The dihedral angles between the phenyl rings and the pyrazine ring are 9.56 (14) and 58.99 (14)° for one mdpp ligand and 9.34 (14) and 79.94 (15)° for the other

Report on grade assessment situation of the 12 prevention and control center pilot in Sichuan Province

目的  了解疾病预防控制机构（简称疾控机构）能力建设、经费保障、运行管理等情况，探索全省疾控等级评审方法和程序。方法  组织专家按照统一的评审标准对12家试点单位在政策环境、基础条件、疾病预防控制、检验检测、健康危害相关因素、信息化建设等7大类38个指标167个参数进行现场评审。结果  机构得分最高是自贡市，考核内容得分率较低的是检验检测和健康危害因素监测与控制，创建过程中各级政府对疾控机构在人、财、物方面均有不同程度的投入，A类和B类项目开展率有所增加，制定了疾控机构三级两等的评审标准。结论  疾控机构等级评审是疾控机构标准化建设和发展的有力抓手，通过评审能发现短板、弥补不足，增强政府在卫生防病方面的主体责任意识。Objective: To understand the situation of ability construction, funds guarantee, operation management of disease control agency, trying to figure out assessment method and program for prevention and control center. Methods: According to the unified standard, evaluation experts were organized to evaluate 12 pilot units. The assessment include 7 categories, 38 indicators and 167 parameters:  the policy environment, basic conditions, disease prevention and control, inspection, health relative factors, information construction, etc. Results: Zigong scored highest in all instituions. Inspection and health hazards monitoring and control scored lower in all categories.  In the process of setting up, all levels of government have different input on personnel, property and goods to prevention and control center. The development rate of type A and type B project increased. The classification standards were produced. Conclusion: Grade assessment is important to construction and development standardization of disease control agency. The assessment can find the weakness, make up the deficiency, strengthen responsibility consciousness of the government