英语翻译Three main types of synthetic fibers are used in the Uni

英语翻译
Three main types of synthetic fibers are used in the United Satates to reinforce plastic materials:glass,aramid and carbon.Glass is by far the most widely used reinforcement fiber and is the lowest in cost.Aramid and carbon fibers have high strengths and low densitise and so are used in many applications,particularly aerospace,in spite of teir higher cost.
Glass fibers are used to reinforce plastic matrices to form structural composites and molding compounds.Glass-fiber plastic composite materials have the following favorable charcteristics:high strength-to-weight ratio;good dimensional stability;good resistance to heat,cold,moisture,and corrosion;good electrical insulation properties;ease of fabrication;and relatively low cost.
The to most important types of glass used to produce glass fibers for composites are E(electrical)and S(high-strength)glasses.
E glass is the most commonly used glass for continuous fiber.Basically,E glass is a limealuminum-borosilicate glass with zero or low sodium and potassium levels.The basic composition of E glass ranges from 52 to 56 percent SiO2 12 to 16 percent Al2O3,16 to 25 percent CaO,and 8 to 13 percent B2O3.E glass has a tensile strength of about 500 ksi(3.44 GPa)in the virgin condition and a modulus of elasticity of 10.5 Msi(72.3 GPa).

在美国被用于强化塑料材料的合成纤维主要有三种类型：玻璃,芳纶和碳纤维.玻璃是目前使用最广泛的增强纤维,且成本最低的.芳纶,碳纤维具有高强度和低密度的特点,所以尽管其成本较高,仍被应用于众多领域中,特别是航空航天领域.
玻璃纤维被用于增强塑料矩阵,以形成结构复合材料和模塑化合物.玻璃纤维塑料复合材料具有以下良好特性：高强度重量比；良好的尺寸稳定性；良好的耐热,耐寒,防潮,耐腐蚀性能；良好的电气绝缘性能,易于制造和相对较低的成本.
用于生产玻璃纤维复合材料的最重要玻璃类型是E（电气）和S（高强度）玻璃.
E玻璃是连续纤维中最常用的玻璃.E玻璃,基本上就是一种石灰铝硼硅玻璃,钠和钾的含量为零或较低.E玻璃的基本成分是52至56％的二氧化硅,12％至16％的氧化铝,16至25％的氧化钙,和8％至13％的氧化硼.在初始条件下,E玻璃具有约500千磅/平方英寸的（平均分GPA3.44）抗拉强度和10.5微星（72.3 GPa）的弹性模量.