学科：水文地质学 词目：永久硬度 英文：permanent hardness 释文：水沸腾后,不沉淀的仍以离子形式含于水中的ca2+、Mg2+的含量,称水的永久硬度。永久硬度和暂时硬度之和曾称总硬度(total hardness),它是天然条件下水中Ca2+、Mg2+数量的总和(标准术语为非碳酸盐钙镁离子浓度)。
结果表明金属活性助剂mca，在不同的硫化体系中可提高丁腈橡胶的拉伸强度、硬度，改善丁腈橡胶的耐热老化性能及压缩永久变形性能。
The results have shown that MCA can increase tensile strength and hardness of NBR and also improve the properties of resistance to heat aging and compression set of NBR as well.
结果表明，高羧基丁腈橡胶具有硬度、拉伸强度和定伸应力高，耐磨性好，压缩永久变形大，加工安全性较差等特点；
The results showed that the high carboxylated NBR featured high hardness, tensile strength and modulus, good abrasion resistance, but greater permanent set and poorer processing safety;
引起材料永久变形的机械操作，如弯曲、辗制、拔制等。在室温下操作，提高不锈钢的硬度及强度。
Any mechanical operation that creates permanent deformation, such as bending, rolling, drawing, etc. performed at room temperature that increases the hardness and strength of the stainless steel.
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