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1.
三峡升船机船厢室段塔柱承重结构的横梁混凝土浇筑施工难度大、复杂性高、无成熟技术可供参考。本文结合三峡升船机塔柱横梁混凝土浇筑的结构特点以及施工特性,总结了三峡升船机续建工程顶部横梁混凝土的施工技术,即采用分层、分块浇筑的办法,通过科学计算后进行合理的施工机械布置和浇筑施工管理,以保证塔柱横梁混凝土的施工质量。通过对贝雷架支撑系统的监测结果分析可知,贝雷架支撑系统的应力变形、挠度变形以及排架变形均满足施工承载要求,筒体位移亦满足技术要求,贝雷架支撑系统稳定、安全。三峡升船机塔柱横梁混凝土施工实践证明了本技术方案的有效性与可靠性,亦可为类似工程的施工组织设计与现场实施工作提供一定的参考。  相似文献   

2.
本文介绍了三峡升船机塔柱横梁混凝土施工支撑系统的实施方案,从贝雷架支撑体系所承受荷载要求、结构强度要求以及变形稳定性要求出发,通过科学计算制定出合理的贝雷架支撑系统的支座系统设计方案、结构设计方案以及上部钢管排架设计方案,并对贝雷架支撑系统以及相应的塔柱混凝土墙体结构在混凝土浇筑前后以及混凝土浇筑过程中的应力(应变)、变形、位移进行了监测。监测结果表明,横梁支撑系统满足了横梁浇筑支撑要求,施工质量优良,安全可靠,设计与施工方案可行。  相似文献   

3.
本文采用直流反应磁控溅射方法在平面玻璃上制备了ZnO薄膜.所得的ZnO薄膜利用X光衍射,扫描电子显微镜和原子力显微镜进行分析和表征.实验结果表明,ZnO薄膜的结构和电学性质与合成条件密切相关.并测试了ZnO薄膜的温差电动势,得出薄膜中的载流子浓度越大,温差电动势率越小;ZnO薄膜厚度越大,温差电动势率越小.本文对其结果进行了理论分析.  相似文献   

4.
研究了氧分压对ZnO薄膜温差电动势的影响.用直流反应磁控溅射方法成功地制备了C轴取向性能良好的ZnO薄膜.实验研究发现,温差电动势和磁温差电动势随温度的变化呈线形关系.氧分压越大,温差电动势率越小.研究结果还表明,磁温差电动势比温差电动势小.  相似文献   

5.
长期监测中结构温度效应分离的一种新方法   总被引:2,自引:0,他引:2  
利用结构长期监测信号的多尺度特性,提出较为精确分离温度效应的自适应带宽滤波方法。按照多尺度分析思想,将温度和温度效应在日温差、年温差和聚然降温等不同时间尺度上展开,利用仅日温差效应与结构上的其他效应在时间尺度上具有不相耦合的特点,通过理论论证获得温度和温度效应具有线性相关特性,结合粒子群优化算法和滤波算法自适应改变日温差效应时间尺度的频率带宽,从而通过回归统计日温差和日温差效应达到精确分离监测信号中的温度效应之目的。分析结果表明:该方法较小波分析方法更能准确分离结构监测信号中的温度效应,为从长期监测信号中进行损伤识别提供了基础数据。  相似文献   

6.
张欢  周广东  吴二军 《工程力学》2017,34(3):124-130
为了建立可靠的大跨桥梁全寿命温差极值分布模型,提出采用广义帕累托分布(Generalized Pareto Distribution,GPD)对超阈值温差的统计特征进行描述,并给出了超阈值温差样本相关性的去除方法和最优阈值的确定方法。为了融合温差分布的先期经验信息和不断递增的温差监测样本,建立了考虑参数更新的贝叶斯估计方法,利用Gibbs抽样对贝叶斯后验分布进行计算,进而得到准确的基于广义帕累托分布的温差极值分布模型。最后利用九堡大桥长期监测温差数据进行了验证。研究结果表明,广义帕累托分布能够对超阈值温差样本的尾部统计特征进行准确描述,提出的考虑参数更新的温差极值分布贝叶斯估计方法能够对广义帕累托分布的参数进行可靠估计,估计的统计模型比极大似然估计计算的结果更接近真实情况。研究结果可为大跨桥梁温差特性分析提供参考。  相似文献   

7.
变形对高层建筑物的安全影响是非常大的,所以,变形监测就显得非常重要。本文以高层建筑物静态变形监测为对象,首先,分析了高层建筑物变形监测的种类,并探讨了变形监测方案的设计思路,探讨了观测周期的确定方法,在此基础上,探讨了建筑变形监测的具体方法和精度分析。  相似文献   

8.
王旭虹  朱虹等 《工程力学》2001,(A01):931-935
本文采用空间线弹性有限单元法对三峡升船机塔柱结构在四种温度作用下的反应进行了计算分析,比较了不同联系方式和不同温度边界对结构变形形态和应力状况的影响,为设计提供了依据。  相似文献   

9.
李丽  常仁杰  方亮  陈希明  刘俊 《真空》2008,45(2):53-56
用直流反应磁控溅射方法在透明平面玻璃上制备出Al掺杂ZnO薄膜,并对其结构和温差电动势率进行研究.实验结果表明,所制备样品具有C轴择优取向的多晶结构,温差电动势随着温差(△T)的增大而呈线性增加.并且样品的电阻越大,温差电动势率越小.在室温附近的环境温度对温差电动势率几乎无影响.退火处理后,温差电动势率增大.实验还发现,在外加磁场时,温差电动势率稍微减小.  相似文献   

10.
本文从监测对象的选择、监测项目的确定、监测点的布置以及监测结果的评价等方面详细介绍了三峡升船机横梁支撑系统的安全监测情况。监测项目包括:贝雷架支撑系统在混凝土浇筑前后以及混凝土浇筑过程中的应力、应变和位移监测;相应的塔柱混凝土墙体结构变形监测;横梁排架的立杆垂直度和位移监测。通过监测结果与原型荷载试验中获取的基础数据的比较分析表明:在施工过程中,横梁混凝土支撑体系安全可靠,应力、应变和位移等监测指标均满足设计要求,能够保证横梁混凝土的顺利浇筑。同时,本工程在安全监测方面建立的方案与技术体系可为其他同类工程的安全监测提供参考和借鉴。  相似文献   

11.
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……  相似文献   

12.
A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.  相似文献   

13.
Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.  相似文献   

14.
The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……  相似文献   

15.
Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.  相似文献   

16.
We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.  相似文献   

17.
Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.  相似文献   

18.
ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.  相似文献   

19.
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from  相似文献   

20.
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.  相似文献   

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