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组合梁斜拉桥索力优化与索塔锚固传力性能研究
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作者 荆华东 耿博光 +1 位作者 朱瑞广 栾儒秀 《科技通报》 2023年第12期79-84,共6页
本文采用有限元分析方法,通过一种索力优化实用方法提出成桥恒载状态索力,分析了在成桥索力下钢混组合索塔锚固结构受力特性。在分别考虑单节段和多节段索力作用的条件下,对锚固结构节段内各构件间以及相邻节段间的索力分配进行分析。... 本文采用有限元分析方法,通过一种索力优化实用方法提出成桥恒载状态索力,分析了在成桥索力下钢混组合索塔锚固结构受力特性。在分别考虑单节段和多节段索力作用的条件下,对锚固结构节段内各构件间以及相邻节段间的索力分配进行分析。结果显示,单节段索力水平分力主要由索力施加节段及相邻的节段共同承担,索力施加节段承担了80%以上的水平力,最远离节段承担的水平力小于10%;对索力在塔柱节段各构件间传递而言,钢锚箱侧板和塔柱混凝土侧壁承担的水平力比例分别约为70%和10%。多节段索力作用下,各节段承担的水平力与该节段施加的索力水平分力值较为接近。索力施加节段的混凝土侧壁与钢锚箱所承担的竖向力比例分别为64.7%和35.3%,位于最下方节段混凝土与钢锚箱竖向力比例分别为86.2%和13.8%,整个塔柱节段在向下传递竖向力时,剪力钉与混凝土的连接锚固发挥了有效传力作用。 展开更多
关键词 斜拉桥 索力优化 有限元模拟 索塔 内置钢锚箱 受力性能
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日粮结构多样性对断奶仔猪生长性能和营养物质消化率的影响 被引量:1
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作者 朱锐广 韩亚楠 +1 位作者 霍军 张利卫 《中国饲料》 北大核心 2018年第24期59-63,共5页
文章旨在研究断奶仔猪生长早期和后期采用不同结构日粮对其生长性能和营养物质表观消化率的影响。试验选择体重一致、21 d断奶的三元仔猪400头,随机分为5组,每组4个重复,每个重复20头。试验早期(21~42 d)采用5种日粮,处理1组(对照组)... 文章旨在研究断奶仔猪生长早期和后期采用不同结构日粮对其生长性能和营养物质表观消化率的影响。试验选择体重一致、21 d断奶的三元仔猪400头,随机分为5组,每组4个重复,每个重复20头。试验早期(21~42 d)采用5种日粮,处理1组(对照组)为玉米-豆粕-低乳糖-低鱼粉型,处理2组为膨化玉米-豆粕-高乳糖-高鱼粉型,处理3组为玉米-豆粕-高乳糖-高鱼粉型,处理4组为膨化玉米-豆粕-高乳糖-低鱼粉型,处理5组为膨化玉米-豆粕-低鱼粉-高乳糖型。试验后期(43~64 d),将试验早期的猪只按每2个重复(同一组)分别饲喂A和B两种日粮,A为膨化玉米-豆粕-鱼粉-乳清粉型,B为全谷物日粮型。结果 :各组对21~28 d、29~42 d及21~42 d仔猪的平均日增重、平均日采食量和料比均无显著影响(P> 0.05)。与处理1组相比,其他各组显著降低了21~28 d、29~42 d及21~42 d仔猪的腹泻指数(P <0.05);试验早期和试验后期日粮对43~64 d仔猪各阶段的生长性能和腹泻指数均无显著影响(P> 0.05)。试验早期,与处理1组相比,处理2、4和5组显著提高30 d仔猪有机物的表观消化率(P <0.05);试验后期两种日粮对50 d仔猪有机物、干物质、粗蛋白质及总能表观消化率均无显著差异(P> 0.05)。结论 :在本试验条件下,与其他多样性日粮相比,21 d断奶仔猪饲喂玉米-豆粕、低乳糖和低鱼粉型日粮对生长性能无显著影响。断奶仔猪生长后期(43~64 d)日粮采用高蛋白谷物日粮可以促进生长性能。 展开更多
关键词 断奶仔猪 日粮结构 生长性能 养分消化率
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Effects of Fleckvieh on the Performance of Dual-Purpose Cattle Improved by Hybridization with Local Beef Cows
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作者 Wang Linfeng Yang Gaiqing +7 位作者 Lian Hongxia Yan Ping Liu Xian Liu Yan Wang Wenhui zhu ruiguang Li Ming Yang Guoyu 《Animal Husbandry and Feed Science》 CAS 2015年第6期322-326,357,共6页
[Objective] The paper aimed to study the improved effect of local beef cattle with Fleckvieh cattle and provide theoretical basic data for local cattle industry in central plain agricultural area in China. [Method] Wi... [Objective] The paper aimed to study the improved effect of local beef cattle with Fleckvieh cattle and provide theoretical basic data for local cattle industry in central plain agricultural area in China. [Method] With 500 local beef cattle as female parents and Fleckvieh cattle as male parents,hybridization improvement was conducted via artificial insemination. The growth performance,slaughter performance,milk performance and milk components of F1 and F2 hybrids were measured. [Result] The birth body weights of F2 were significantly higher than those of local beef cow,but there was no remarkable difference between F1 and local beef cow or F1 and F2. The growth rates of F1 and F2 at different stages were higher than those of local beef cattle. The slaughter performance,such as carcass weight( P < 0. 05),dressing percentage,net meat rate( P < 0. 05),marbling score of F1 and F2 were higher than those of local beef cow. Milk production performance,such as actual milk yield,305 d corrected milk yield and 4% standard milk yield of F2 were signally higher than those of F1 and local beef cattle( P< 0. 05),and F1 was markedly higher than local beef cattle( P < 0. 05). For milk composition,although milk fat percentage,milk protein rate,lactose rate and total solids( TS) of F1 and F2 were slightly lowered compared with local beef cattle at varying degrees,they were still at high levels compared with Holstein cows.[Conclusion]Fleckvieh cattle,as a male parent,can significantly improved growth performance,slaughter performance and milk performance of offsprings. It would also increases the economic efficiency of local beef cattle by higher quality and price,as well as changing production model from beef to dual purpose of beef and milk. 展开更多
关键词 Dual-purpose cattle Hybridization and improvement Growth performance Production performance Milk quality
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