With this in minds, many researchers have proposed a variety of models for describing the nonlinear fracture of concrete for the past decades. Amid them most take the critical stress intensity factor KIC as the fracture toughness, a sign of ability to resist the crack extension. 对此,在过去的几十年里,众多研究人员提出了很多描述混凝土非线性断裂的模型,而其中的大多数断裂模型都以临界应力强度因子K(Ic)作为抵抗裂缝扩展阻力的断裂韧度。
The result is the same in the content of inorganic ion. Young seedlings 'rhizome can resist absorbing Na+. But it absorbs K+ actively and transports it. Under a certain density saline-alkali stress, young seeding can specific property absorbing and accumulating anion. 无机离子含量的结果也同样显示出,羊草幼苗根系能够抑制吸收Na离子,主动吸收并向上转运K离子;在受到一定浓度范围盐碱胁迫时,羊草幼苗还能特异性吸收、积累阴离子。