Dialgebra cohomology as a G-algebra

It is well known that the Hochschild cohomology of an associative algebra admits a G-algebra structure. In this paper we show that the dialgebra cohomology of an associative dialgebra has a similar structure, which is induced from a homotopy G-algebra structure on the dialgebra cochain complex .

     

Positive Charges in the Brace Region Facilitate the Membrane Disruption of MLKL-NTR in Necroptosis

Necroptosis is a type of programmed cell death executed through the plasma membrane disruption by mixed lineage kinase domain-like protein (MLKL). Previous studies have revealed that an N-terminal four-helix bundle domain (NBD) of MLKL is the executioner domain for the membrane permeabilization, which is auto-inhibited by the first brace helix (H6). After necroptosis initiation, this inhibitory brace helix detaches and the NBD can integrate into the membrane, and hence leads to necroptotic cell death. However, how the NBD is released and induces membrane rupture is poorly understood. Here, we reconstituted MLKL_2–154 into membrane mimetic bicelles and observed the structure disruption and membrane release of the first brace helix that is regulated by negatively charged phospholipids in a dose-dependent manner. Using molecular dynamics simulation we found that the brace region in an isolated, auto-inhibited MLKL_2–154 becomes intrinsically disordered in solution after 7 ns dynamic motion. Further investigations demonstrated that a cluster of arginines in the C-terminus of MLKL_2–154 is important for the molecular conformational switch. Functional mutagenesis showed that mutating these arginines to glutamates hindered the membrane disruption of full-length MLKL and thus inhibited the necroptotic cell death. These findings suggest that the brace helix also plays an active role in MLKL regulation, rather than an auto-inhibitory domain.     

粘滞和粘弹性阻尼器减震结构的随机响应特性

利用积分型本构关系,针对带支撑任意线性粘滞和粘弹性阻尼器单自由度耗能结构,建立了微分和积分混合地震响应方程;基于随机平均分析法,推导出耗能结构振幅与相位瞬态联合概率密度函数、位移与速度瞬态联合概率密度函数、位移与速度瞬态响应方差、振幅动力可靠性、振幅首超时间任意阶统计矩的一般解析解;给出了带支撑广义Maxwell阻尼器和广义微分模型阻尼器耗能结构上述各种随机响应特性,从而建立了带支撑任意线性粘滞和粘弹性阻尼器单自由度减震结构的各种随机响应特性分析的统一解析解法。     

粘滞和粘弹性阻尼器减震结构的等效阻尼

利用积分型本构关系,建立了带支撑的一般粘滞和粘弹性阻尼器单自由度耗能结构的微分-积分混合地震响应方程;基于与随机平均分析完全相同的等效准则,推导了可直接应用反应谱的阻尼器的等效刚度和等效阻尼的解析公式;得到了带支撑广义Maxwell阻尼器和广义微分模型阻尼器的等效刚度和等效阻尼的一般结果。通过与一些典型问题的数值计算结果比较,表明了所提方法的有效性。     

Symmetric Brace Algebras

We develop a symmetric analog of brace algebras and discuss the relation of such algebras to L_∞-algebras. We give an alternate proof that the category of symmetric brace algebras is isomorphic to the category of pre-Lie algebras. As an application, symmetric braces are used to describe transfers of strongly homotopy structures. We then explain how these symmetric brace algebras may be used to examine the L_∞-algebras that result from a particular gauge theory for massless particles of high spin.Mathematics Subject Classifications (2000) 55S20 (primary), 70S15 (secondary).Tom Lada: The research of the first author was supported in part by NSF grant INT-0203119.Martin Markl: The research of the second author was supported by grant MŠMT ME 603 and by the Academy of Sciences of the Czech Republic, Institutional Research Plan No. AV0Z10190503.     

带剪刀撑木框架墙体抗剪性能试验研究

彩图制作了5组10片木框架剪力墙分别进行单向和反复荷载试验,研究了剪刀撑及不同覆面板对剪力墙的抗剪强度、弹性抗侧刚度、极限位移、耗能的影响。试验数据说明:增加剪刀撑的墙体最大墙骨柱上拔量仅为未加剪刀撑的对照墙体墙的22.7%,剪刀撑对于抑制墙骨柱上拔的现象有显著作用,能控制墙体面板钉连接破坏先于墙骨柱连接破坏;而且剪刀撑还能增大墙体刚度,约束墙体位移。此外,试验各项参数表明:采用国产胶合板作为覆面板的墙体的抗剪性能良好,说明国产胶合板可以替代OSB板应用于剪力墙制作;而采用国产花旗龙板作为面板的墙体抗剪强度远远低于GB50005-2003《木结构设计规范》中采用木基结构板材的剪力墙抗剪强度设计值(fvd为4.7kN/m)的指标要求,建议在实践中仅作为强度储备。     

Brace generation

A brace is a connected bipartite graph with a perfect matching and at least six vertices such that for every pair of nonadjacent edges, there is a perfect matching containing the edges. We give a method for generating all braces. © 2001 John Wiley & Sons, Inc. J Graph Theory 38: 124–169, 2001     

长条形基坑带顶部支撑排桩支护体系空间变形研究

提出了一种建立具有固定双面约束多点摩擦的多体系统动力学方程的方法. 用笛卡尔坐标阵 描述系统的位形,根据局部方法的递推关系建立系统的约束方程,应用第一类Lagrange方程 建立该系统的动力学方程,使得具有摩擦的约束面的法向力与Lagrange乘子一一对应,便于 摩擦力的分析与计算,并用矩阵形式给出了摩擦力的广义力的一般表达式. 应用增广法将微 分-代数方程组转化为常微分方程组,并用分块矩阵的形式给出,以便于方程的编程与计算. 给出了一种改进的试算法,可提高计算效率. 最后给出了一个算例,应用试算法和RK法对算 例进行了数值仿真.