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大桥用镀锌钢丝必须同时满足扭转≥8次,松弛率≤2.5%,抗拉强度≥1 670 MPa。介绍大桥斜拉索用镀锌钢丝和斜拉索制作工艺。选用宝钢B82MnQL盘条生产7.0 mm镀锌钢丝,锌层面质量≥300 g/m2。镀锌钢丝生产过程中应提高钢丝表面质量、直线度及镦头性能。降低斜拉索索体扭转的方法:改进绞制与挤塑工序牵引方式;改进绞制弯道以保持斜拉索绞制节距稳定;改进索体绕包张力。对新型斜拉索密封体系进行研发。斜拉索疲劳性能改进措施:提高镀锌钢丝表面质量均匀性、直线性和直径精度。生产的镀锌钢丝斜拉索经检验和使用,能够满足用户的特殊要求。 相似文献
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针对X82B盘条在使用过程中出现的脆断现象,对断裂样品形貌、金相组织、力学性能等进行分析检测,得出断裂原因:(1)X82B盘条放线脆断大都为局部缺陷所致。(2)擦伤、刮伤等表面缺陷和心部马氏体、表面网状渗碳体等不良组织会导致盘条发生脆断。(3)连铸过程的拉速不稳或润滑不良都会造成盘条的局部裂纹并导致脆断。(4)盘条轧制后期的吐丝、辊道运输、集卷、打捆等环节也易造成盘条的局部裂纹并导致脆断。在盘条生产和后续加工过程中,严格过程控制可有效降低盘条发生脆断的几率。 相似文献
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A jet-stirred reactor study of ethyl propanoate, a model biodiesel molecule, has been carried out at 10 atm pressure, using 0.1% fuel at equivalence ratios of 0.3, 0.6, 1.0 and 2.0 and at temperatures in the range 750-1100 K with a constant residence time of 0.7 seconds. Concentration profiles of ethyl propanoate were measured together with those of major intermediates, ethylene, propanoic acid, methane and formaldehyde, and major products, water, carbon dioxide and carbon monoxide. This data was used to further validate a previously published detailed chemical kinetic mechanism, containing 139 species and 790 reversible reactions. It was found that this mechanism required a significant increase in the rate constant of the six-centered unimolecular elimination reaction which produces ethylene and propanoic acid in order to correctly reproduce the measured concentrations of propanoic acid. The revised mechanism was then used to re-simulate shock tube ignition delay data with good agreement observed. Rate of production and sensitivity analyses were carried out under the experimental conditions, highlighting the importance that ethylene chemistry has on the overall reactivity of the system. 相似文献
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通过对塔中I号坡折带塔中82井区原油进行地球化学分析(包括分子筛合除去正构烷烃分析)来探讨其特征和成因,结果表明:原油族组成中饱和烃占绝对优势,而饱和烃中以低碳数正构烷烃为主,C 21-/C 22+ 值达1.4~5.4,生物标志物的含量极低;甾烷C27-C28-C29呈“V”字型分布,重排甾烷的含量较高;萜烷中三环萜的含量较高而五环萜含量极低,且三环萜以C20或C23为主峰;芳烃中三芳甾烷的含量很低,三芴系列化合物中硫芴含量较高;原油碳同位素较轻,其饱和烃的碳同位素值δ13C<-32.8‰(这些特征有别于塔东2井的寒武系原油);原油的成熟度RO值为0.8%左右。推断塔中82井区的原油可能并非是有机质在高成熟阶段生成的凝析油,而是中等成熟的中-上奥陶统源岩生成的正常原油在成藏后由于寒武系天然气的注入,发生了蒸发分馏作用并运移至目前的储层中再次成藏。 相似文献
87.
This study examines the effect of unsaturation on the combustion of fatty acid methyl esters (FAME). New experimental results were obtained for the oxidation of methyl (E)-2-butenoate (MC, unsaturated C4 FAME) and methyl butanoate (MB, saturated C4 FAME) in a jet-stirred reactor (JSR) at atmospheric pressure under dilute conditions over the temperature range 850-1400 K, and two equivalence ratios (Φ=0.375,0.75) with a residence time of 0.07 s. The results consist of concentration profiles of the reactants, stable intermediates, and final products, measured by probe sampling followed by on-line and off-line gas chromatography analyses. The oxidation of MC and MB in the JSR and under counterflow diffusion flame conditions was modeled using a new detailed chemical kinetic reaction mechanism (301 species and 1516 reactions) derived from previous schemes proposed in the literature. The laminar counterflow flame and JSR (for ?=1.13) experimental results used were from a previous study on the comparison of the combustion of both compounds. Sensitivity analyses and reaction path analyses, based on rates of reaction, were used to interpret the results. The data and the model show that MC has reaction pathways analogous to that of MB under the present conditions. The model of MC oxidation provides a better understanding of the effect of the ester function on combustion, and the effect of unsaturation on the combustion of fatty acid methyl ester compounds typically found in biodiesel. 相似文献
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