共查询到18条相似文献,搜索用时 250 毫秒
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介绍大跨度悬索桥主缆索股制造技术现状,通过对盘条索氏体化处理、提高钢丝强度等级、采用锌铝合金镀层替代锌镀层、改进制索工艺,对索夹抗滑移性能进行研究,探索出适合大跨度悬索桥主缆的1 860 MPa等级锌铝合金镀层钢丝索股制作成套技术,并成功应用于国内外多座大跨度悬索桥。 相似文献
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分析在中跨主缆及边跨主缆索夹端部缠丝机缠丝的不同工况,进而论述国产ZLC系列主缆缠丝机索夹端部的缠丝工艺及端部缠丝附件在其中所起的作用。 相似文献
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悬索桥是大跨度桥梁的首选结构,主缆是悬索桥的主要传力承载结构件。悬索桥主缆主要由平行的钢丝(钢绞线)组成,应用较多的是高强度热镀锌钢丝。我国悬索桥主缆主要采用预制平行钢丝索股(PPWS)架设方法,一般采用φ5 mm左右的高强钢丝预制,每股127丝(或91丝),索股两端用热铸锚锚固。国内PPWS制造技术工艺从无到有,经过不断改进提高,已经达到国际先进水平。介绍国内悬索桥主缆PPWS制造现行工艺技术,通过放索试验和现场工程实施,分析生产线特点、存在的问题和实际应用中的主要改进成果。结合未来特大跨度悬索桥建设探讨可能出现的问题和主缆钢丝、索股制作的改进方向。 相似文献
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介绍典型的钢丝绳主索结构,以及钢丝绳主索在小型桥梁上的实际应用情况。采取消除非弹性变形、解决弹性伸长、温度修正等方法达到控制钢丝绳主索制作长度误差的目的,以此提高钢丝绳主索质量。对施工时索体上测量标记的设置方法进行说明。提出索体表面加高密度聚乙烯塑料护套和索体表面镀锌-5%铝-混合稀土合金是主索提高防腐性能的主要发展方向。 相似文献
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桥梁缆索用热镀锌钢丝的性能要求与加工工艺 总被引:4,自引:4,他引:0
介绍桥梁缆索用高强度热镀锌钢丝在我国的应用和发展,说明相关标准的应用情况,指出钢丝的扭转和松弛指标可以根据实际的结构有所侧重。分别介绍斜拉索钢丝和主缆钢丝的生产流程,并对线材表面预处理生产线、拉拔生产线、热镀锌生产线、稳定化处理生产线及矫直进行分析,指出各工序的作用和控制要点,特别强调稳定化处理线的张力施加方式、张力、温度对产品性能的影响。结合高强度热镀锌钢丝的使用情况,对钢丝性能指标的选择、钢丝的表面质量、盘条和钢丝电接头、钢丝的镀层质量提出建议。 相似文献
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D.W. LAMB 《Australian Journal of Grape and Wine Research》2009,15(1):79-84
Background and Aims: Current methods of frost protection in vineyards involve fans, air heaters or sprinklers; each is limited by environmental constraints or available water. An alternative, all-electrical technique offers growers wider choice to match options with their vineyard operations. This study evaluates the ability of electrical heating cables, wrapped around the vine cordons, to protect inflorescences from frost damage.
Methods and Results: Five heating cable treatments in six replicates were applied to a 2-ha block of Sauvignon Blanc in the southern New England Region of Australia. Vines were subjected to a single −3°C frost event in November 2006 when at approximately 30% capfall. Non-heated vines suffered 41% (Control) and 46% (No heat) inflorescence loss. Those subjected to Low heat suffered a 28% loss, Medium-heated vines suffered a 16% loss and High-heated vines suffered a 13% loss. Qualitative scoring of the vines indicated that more than half of the Medium-/High-heated vines suffered no appreciate damage, whereas all non-heated vines suffered some form of potential crop loss or damage.
Conclusion: Electrical heating cables of minimum 10 W/m power rating were found to significantly reduce frost damage to inflorescences at 30% capfall.
Significance of the Study: At approximately 43 kW/ha, electrical heating cable offers an alternative frost protection method for small vineyards. 相似文献
Methods and Results: Five heating cable treatments in six replicates were applied to a 2-ha block of Sauvignon Blanc in the southern New England Region of Australia. Vines were subjected to a single −3°C frost event in November 2006 when at approximately 30% capfall. Non-heated vines suffered 41% (Control) and 46% (No heat) inflorescence loss. Those subjected to Low heat suffered a 28% loss, Medium-heated vines suffered a 16% loss and High-heated vines suffered a 13% loss. Qualitative scoring of the vines indicated that more than half of the Medium-/High-heated vines suffered no appreciate damage, whereas all non-heated vines suffered some form of potential crop loss or damage.
Conclusion: Electrical heating cables of minimum 10 W/m power rating were found to significantly reduce frost damage to inflorescences at 30% capfall.
Significance of the Study: At approximately 43 kW/ha, electrical heating cable offers an alternative frost protection method for small vineyards. 相似文献
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针对某型号飞机飞行中发动机操纵钢索发生断丝卡滞问题,根据油门操纵拉杆的结构及工作原理进行分析。采用扫描电镜和化学成分分析等方法,综合分析后得出产生断丝卡滞的主要原因是钢索捻制时有倒刺,拉杆制造过程中该部位恰好位于压接头附近,在后续使用维护中油门操纵拉杆受到推拉作用,钢丝刺出钢索表面而发生卡滞。对上述现象提出改进措施:加强油门操纵拉杆的使用维护和保养,防止因摩擦力过大导致拉杆运动受阻;加强油门操纵拉杆钢索的表面质量检查,发现钢索有断头、生锈、松散等现象应及时更换;注意检查外套铜管内腔,防止外来多余物进入铜管导致油门拉杆运动受阻而卡滞。 相似文献
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吕志 《郑州轻工业学院学报(自然科学版)》2014,(2):91-95
建立了桥式起重机变绳长三维吊车系统的动力学数学模型.该模型在桥式起重机设立坐标系时,选取系统目标控制变量作为坐标系的变量值,运用运动学基本原理分析小车的坐标位置,通过拉格朗日方程建立模型.该模型不仅将模型变量与控制目标变量对应起来,而且将系统的三维运动以及由这些运动导致的抓斗摆角的变化考虑其中.仿真结果表明,模型具有简单、直观、效果好等特性. 相似文献
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<正>经过十多年的不懈努力,PET无菌冷灌装技术已越来越完善,生产的饮料品种也越来越多,包括果蔬汁饮料、茶饮料、运动饮料、碳酸饮料、水等等。目前在北美和欧洲PET瓶装乳饮料已非常普遍。在吹瓶过程中通过增加适当的阻隔层,解决瓶子的透气性,使得PET瓶在啤酒领域的应用也变得更加现实。 相似文献
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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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Kawarai T Arai S Furukawa S Ogihara H Yamasaki M 《Journal of Bioscience and Bioengineering》2006,101(6):515-518
We previously reported that the postgrowth of Escherichia coli K-12 after high-hydrostatic-pressure treatment (HPT) as moderate as 75 MPa for 30 min at 37 degrees C induced the formation of elongated cells due to an HPT-induced disorder in FtsZ ring formation, which is essential for cell division. Because an FtsZ ring is known as a bacterial cytoskeleton, we examined the effect of HPT on a eukaryotic cytoskeleton, such as actin cables (long bundles of actin filaments), of Saccharomyces cerevisiae. We found that actin cables disappeared after HPT (100 MPa) and were not reorganized until 3.5 h of growth after HPT. As long as actin cables disappeared, budding did not start. We also demonstrated that the in vitro polymerization of actin monomers was highly sensitive to HPT. 相似文献