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基于梯度半径差的曲线钢箱梁差速顶推控制技术

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黑龙江交通科技 2024年第6期47卷 113-116,120页

作者：马玉军鞠鹏袁航李贤锋石学坤王邢宇中铁十局集团青岛工程公司山东青岛266600 山东交通学院山东济南250357

采用传统的顶推施工工艺对曲线钢箱梁进行顶推施工时,需要通过调整水平顶和滑道的角度,不断对顶推路线进行人工纠偏,纠偏难度较大,施工工艺复杂且施工风险较高。为确保钢箱梁在曲线顶推的过程中能够按设计线路移动,基于梯度半径差的差... 详细信息

采用传统的顶推施工工艺对曲线钢箱梁进行顶推施工时,需要通过调整水平顶和滑道的角度,不断对顶推路线进行人工纠偏,纠偏难度较大,施工工艺复杂且施工风险较高。为确保钢箱梁在曲线顶推的过程中能够按设计线路移动,基于梯度半径差的差速顶推控制理论,提出了一种曲线钢箱梁差速顶推控制技术,进一步研发了差速顶推控制系统。在曲线钢箱梁顶推过程中,通过差速顶推控制系统调节钢箱梁内外侧千斤顶的进油流量比例,改变内外侧千斤顶在单位时间内的顶推距离,进而产生顶推行程差,从而使得钢箱梁在曲线路径下按设计线路进行移动。

关键词：曲线钢箱梁顶推施工差速顶推

桥梁顶推施工对既有线高铁桥墩变位影响及沉降预测分析

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黑龙江交通科技 2024年第1期47卷 74-77,82页

作者：朱传忠金增禄刘彦浩李贤锋石学坤王邢宇崔凤坤中铁十局集团青岛工程公司山东青岛266600 山东交通学院山东济南250357

随着桥梁顶推施工在新建线路跨越既有线施工中的广泛应用,关于桥梁顶推施工对既有高铁桥墩变位影响的研究亟待深入。为研究桥梁顶推全过程施工对邻近既有高铁桥墩变位的影响,以郑济铁路ZJTLSG-1标跨京沪高铁特大桥工程为依托,基于监测数... 详细信息

随着桥梁顶推施工在新建线路跨越既有线施工中的广泛应用,关于桥梁顶推施工对既有高铁桥墩变位影响的研究亟待深入。为研究桥梁顶推全过程施工对邻近既有高铁桥墩变位的影响,以郑济铁路ZJTLSG-1标跨京沪高铁特大桥工程为依托,基于监测数据,分析顶推施工关键施工工况对邻近既有高铁桥墩变位及沉降的影响;然后,采用先进的BP神经网络技术对相邻高铁线路工后沉降进行预测。结果表明:(1)既有高铁桥墩在顶推全过程施工完成后发生沉降且既有高铁桥墩水平移动方向与顶推方向相反;(2)既有桥墩的水平位移及竖向位移均从近施工侧到远离施工侧呈递减规律;(3)采用BP神经网络对既有桥墩进行沉降预测,预测值与实测值基本吻合,预测可靠。

关键词：顶推施工桥墩变位 BP神经网络沉降预测

入院即刻肌酐水平对急性心梗患者经皮冠状动脉介入治疗预后的影响

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武汉大学学报（医学版） 2014年第6期35卷 928-931页

作者：时学昆程璐新疆医科大学附属中医医院心内二科新疆乌鲁木齐830000

目的:探讨入院即刻肌酐水平对急性心梗患者经皮冠状动脉介入(PCI)治疗预后的影响。方法:对395例急性心梗并于12h内行PCI治疗患者按照入院即刻肌酐水平分为血肌酐升高组和正常组,比较两组患者短期观察和长期随访结局,并对长期随访不良结... 详细信息

目的:探讨入院即刻肌酐水平对急性心梗患者经皮冠状动脉介入(PCI)治疗预后的影响。方法:对395例急性心梗并于12h内行PCI治疗患者按照入院即刻肌酐水平分为血肌酐升高组和正常组,比较两组患者短期观察和长期随访结局,并对长期随访不良结局的影响因素进行Logistic回归分析。结果:两组患者住院时间差异无统计学意义(P>0.05),血肌酐升高组死亡人数和肌酐值均高于正常组(P0.05);术后随访,两组患者死亡人数、MACE发生率和随访期终点肌酐水平差异均具有统计学意义(P<0.05);将患者死亡和出现MACE作为不良结局分析发现,年龄、糖尿病史、高血压史、陈旧性心梗史、Killip p≥2、血管病变程度≥2、eGFR和入院即刻肌酐水平均为不良结局的影响因素(P<0.05);对影响患者结局的各因素进行逐步Logistic回归分析发现,年龄、陈旧性心梗史、入院即刻肌酐水平和肾小球滤过率为急性心梗患者PCI治疗后出现不良结局的独立危险因素(P<0.05)。结论:入院即刻肌酐水平与患者长期预后关系更为密切,高肌酐水平者预后不良可能性更大。

关键词：肌酐急性心梗经皮冠状动脉介入治疗预后

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电控机械式自动变速器液压换挡执行机构设计

机床与液压 2014年第17期42卷 115-118页

作者：郭朋彦夏斌张宁石学坤冯金泉华北水利水电大学机械学院河南郑州450011 河南农业大学信息与管理科学学院河南郑州450002

在电控机械式自动变速器的设计中,换挡执行机构的设计是重点和难点,其性能的优劣,将直接影响整车的平顺性、舒适性和安全性。以某5挡手动变速箱为基础,根据换挡执行机构的设计要求,开发设计了一款电控液压式换挡执行机构。对液压系统进... 详细信息

在电控机械式自动变速器的设计中,换挡执行机构的设计是重点和难点,其性能的优劣,将直接影响整车的平顺性、舒适性和安全性。以某5挡手动变速箱为基础,根据换挡执行机构的设计要求,开发设计了一款电控液压式换挡执行机构。对液压系统进行了分析,设计了该换挡执行机构的液压系统,并对液压系统的主要元件进行了计算和选型;根据该换挡执行机构、液压原理图和选换挡液压缸分析了该换挡执行机构的工作过程;实际制作了该选换挡执行机构,并对对应的5挡MT变速器进行了AMT改造。试验表明:该选换挡执行机构能够实现该5挡变速箱的选挡和换挡,并且结构简单、定位准确、反应灵敏,换挡品质安全可靠,具有较好的推广应用价值。

关键词： AMT变速箱液压换挡执行机构液压系统液压缸

酶解鱼溶浆粉替代部分鱼粉对黄鳝生长、血清生化及免疫指标的影响

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饲料工业 2024年第16期45卷 85-91页

作者：柳远香石勇马学坤郭勇张俊智胡毅湖南农业大学水产学院湖南长沙410128 湖南省特色水产资源利用工程技术研究中心湖南长沙410128 广东粤海饲料集团股份有限公司广东湛江524000

试验旨在研究酶解鱼溶浆粉对黄鳝(Monopterus albus)生长、肠道消化酶、血清生化及免疫指标的影响。以初始体重为(25.00±0.20)g健康黄鳝为研究对象,设置3个处理组,每组3个重复,每箱50尾黄鳝。酶解鱼溶浆粉分别替代基础饲料(对照组鱼粉... 详细信息

试验旨在研究酶解鱼溶浆粉对黄鳝(Monopterus albus)生长、肠道消化酶、血清生化及免疫指标的影响。以初始体重为(25.00±0.20)g健康黄鳝为研究对象,设置3个处理组,每组3个重复,每箱50尾黄鳝。酶解鱼溶浆粉分别替代基础饲料(对照组鱼粉含量为40%)中0、2.5%和5%的鱼粉,分别记为FM组、SHM2.5组和SHM5.0组,养殖试验持续56 d。结果表明,与FM组相比,酶解鱼溶浆粉替代部分鱼粉(SHM2.5组和SHM5.0组)对黄鳝增重率无显著差异(P>0.05),但肠道胰蛋白酶活性显著升高(P0.05);酶解鱼溶浆粉替代部分鱼粉显著升高血清中免疫球蛋白M、补体4和溶菌酶水平(P<0.05),SHM5.0组血清中葡萄糖、三酰甘油和碱性磷酸酶水平显著升高(P<0.05)。综上所述,酶解鱼溶浆粉适当替代鱼粉对黄鳝的生长、饲料利用和肠道消化酶无不利影响,并且会增强黄鳝的免疫功能。

关键词：酶解鱼溶浆粉黄鳝生长性能血清生化免疫

比较益生菌和中药组合对鸡源大肠杆菌抑菌效果分析

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现代畜牧兽医 2021年第1期 19-22页

作者：史雪坤王慧青苗天姿高乐张东远汪恩强河北农业大学动物医学院河北保定071001 中国科学院天津工业生物技术研究所天津市工业生物系统与过程工程重点实验室天津300308 中科康源(唐山)生物技术有限公司河北唐山063000

试验比较多种益生菌和中药组合对鸡源大肠杆菌的抑菌效果,并对其抑菌机理进行分析。结果表明:益生菌中,枯草芽孢杆菌和植物乳杆菌对鸡源大肠杆菌具有明显的抑菌活性,但地衣芽孢杆菌没有效果。中药组合中,黄连和茯苓、赤芍、金银花、鱼... 详细信息

试验比较多种益生菌和中药组合对鸡源大肠杆菌的抑菌效果,并对其抑菌机理进行分析。结果表明:益生菌中,枯草芽孢杆菌和植物乳杆菌对鸡源大肠杆菌具有明显的抑菌活性,但地衣芽孢杆菌没有效果。中药组合中,黄连和茯苓、赤芍、金银花、鱼腥草、桂枝分别配伍时抑菌效果明显,但中药组合的抑菌效果明显低于益生菌。进一步研究益生菌中的抑菌成分,对植物乳杆菌和枯草芽孢杆菌发酵液进行粗提取、分离和纯化,发现地衣芽孢杆菌和枯草芽孢杆菌可以产生肠杆菌肽,肠杆菌肽是抗菌肽的一种,其对鸡源大肠杆菌有抑制作用。

关键词：益生菌中药组合鸡源大肠杆菌肠杆菌肽抑菌作用

The phytolith carbon sequestration in terrestrial ecosystems:the underestimated potential of bamboo forest

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Ecological Processes 2023年第1期12卷 872-883页

作者： xuekun Cheng Huiru Lv Shuhan Liu Chong Li Pingheng Li Yufeng Zhou Yongjun shi Guomo Zhou State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityLin’anHangzhou 311300China Zhejiang Province Key Think Tank:Institute of Ecological Civilization Zhejiang A&F UniversityLin’anHangzhou 311300China Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration of Zhejiang Province Zhejiang A&F UniversityLin’anHangzhou 311300China School of Environmental and Resources Science Zhejiang A&F UniversityLin’anHangzhou 311300China

Background Terrestrial ecosystems contain significant carbon storage,vital to the global carbon cycle and climate *** in human production activities and environmental factors affect the stability of carbon storage in *** sequestration in plant phytoliths offers a sustainable method for long-term carbon *** occluded in phytoliths(PhytOC)is a kind of carbon that can be stable and not decomposed for a long time,so it is crucial to conduct more in-depth research on *** We undertook a meta-analysis on PhytOC across global terrestrial ecosystems,analyzing 60 articles,encapsulating 534 *** observed notable differences in phytolith and PhytOC contents across various *** forest ecosystems exhibited the highest vegetation phytolith and PhytOC content,while soil phytolith content was most prominent in bamboo forests and PhytOC content in *** activities,such as grassland grazing,had a lesser impact on soil PhytOC transport than actions like cutting and tillage in croplands and *** study separated bamboo ecosystems,analyzing their PhytOC content and revealing an underestimation of their carbon sink *** Notwithstanding our findings,phytoliths’intricate environmental interactions warrant further exploration,crucial for refining ecosystem management and accurately estimating PhytOC *** deepened understanding lays the foundation for studying phytoliths and the carbon sink dynamics.

关键词： Carbon sequestration Phytoliths PhytOC Terrestrial ecosystem Soil carbon

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Compositional dependence of microstructure and tribological properties of plasma sprayed Fe-based metallic glass coatings

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Science China(Technological Sciences) 2012年第5期55卷 1335-1342页

作者： YANG Qin LI Ran LIU ZengQian shi MinJie LUO xuekun ZHANG Tao Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters. Microstructures, thermal stabilities and tribological properties of the sprayed coatings were analyzed. The coating performances showed a strong dependence on the intrinsic characters of the compositions, i.e., glass-forming ability （GFA） and supercooled liquid region （ATx）. The coatings tended to exhibit higher amorphous phase fraction for the composition with higher GFA and lower porosity for that with larger ATX. All the coatings exhibited superior wear resistance compared with the substrate. Higher wear resistance could be obtained in coatings with higher amorphous phase fraction, i.e. higher GFA of the composition. This study has important implications for composition selecting and optimizing in the fabrication of metallic glass coatings.

关键词： metallic glasses microstructure rapid-solidification coating materials X-ray diffraction

Mechanism analysis and performance improvement of mechanized ridge forming of whole plastic film mulched double ridges

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International Journal of Agricultural and Biological Engineering 2020年第5期13卷 107-116页

作者： Fei Dai Xuefeng Song Wuyun Zhao Ruijie shi Fengwei Zhang xuekun Zhang Gansu Provincial Key Laboratory of Aridland Crop Science Gansu Agricultural UniversityLanzhou 730070China College of Mechanical and Electrical Engineering Gansu Agricultural UniversityLanzhou 730070China

In order to achieve high-performance and mechanization construction standard of whole plastic mulched double ridge seedbed,and to meet its forming process and corresponding agronomic requirements of the mechanized double ridge seedbed,the key working parameters such as the speed of rotary blade group,the thickness of upturned sod and the power consumption of rotary blade group under different parameters were analyzed based on related working performance in ridge ***,the test factors and their range of values were finally determined in this *** element method(DEM)simulation was applied in the numerical simulation of the mechanized ridge forming process of whole plastic mulched double ridges,and the ridge forming effect and digging resistance variation characteristics of different types of shovels were *** the forward speed of the combined machine,the penetration angle of the arc-shaped shovel and the depth of rotary tillage as independent variables,and the qualified rate of seedbed tillage as the response value,the mathematical model between the test factors and the qualified rate of the seedbed tillage was established,to explore the influence sequence of the factors on the qualified rate of seedbed tillage,and obtained the following optimal working parameters of the ridge forming device:the advancing velocity of the combined machine of 0.50 m/s,penetration angle of the arc-shaped shovel of 31°,rotary tillage depth of 140 mm,and average qualified rate 95.20%of seedbed tillage in corresponding simulation verification *** test showed that the average qualified rate of seedbed tillage in ridge forming device was 93.60%,which was close to that of the simulation *** actual working condition of the sample machine was basically in line with the simulation process and could relatively precisely reflect the mechanized ridge forming mechanism of whole plastic double *** results showed that the established DEM model and its

关键词： whole plastic film mulched double ridges mechanized ridge forming DEM numerical simulation parameter optimization