全文获取类型
收费全文 | 60篇 |
免费 | 0篇 |
专业分类
公路运输 | 22篇 |
综合类 | 3篇 |
水路运输 | 15篇 |
铁路运输 | 17篇 |
综合运输 | 3篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
排序方式: 共有60条查询结果,搜索用时 15 毫秒
31.
Strain gauges are commonly used for the instrumentation of ship structures to measure ice loads on the basis of shear strain differences. Finite Element Analysis (FEA) is used to determine the load–strain relation of the instrumented area by calculating an Influence Coefficient Matrix (ICM). However, the accuracy of the measurement method and the influence of the load location and load length on the accuracy of the load determination are rarely assessed. Consequently, this paper identifies the accuracy of the ICM, discusses which structures are suitable for measurements of shear strain differences and presents possible improvements regarding these measurements. As load cases are systematically varied over a finite element model, the external load is recalculated based on the resulting shear strains. The number of strain gauges used for the measurement of shear strains has a significant impact on the ICM. For common instrumentation it was found that the ice load can only be accurately determined, if the ice load acts within the instrumented area. To overcome this limitation, an approach to determine the load location is presented among further recommendations. 相似文献
32.
为了解决单一方法对25 Hz相敏轨道电路的故障诊断精度偏低等问题,提出基于最优权值的多方法组合故障诊断模型。首先通过模糊综合评判、灰色关联分析和BP(Back propagation)神经网络3种不同的诊断方法,对轨道电路进行初步故障诊断,然后根据各诊断方法的误判率计算出对应的最优权值,最后对各方法的诊断输出进行最优权值加权平均得到综合诊断的输出结果,确定故障类型。诊断结果表明:组合诊断模型有效地提高了轨道电路故障诊断的准确度,并证明了组合诊断模型的诊断准确度随着诊断方法的数量增加而提高。 相似文献
33.
Shoji Takechi Kazuhiro Aoyama Toshiharu Nomoto 《Journal of Marine Science and Technology》2002,6(3):158-167
In ship hull production, the accuracy of management activities is extremely important. The block positioning operation in
the erection stage is a key process in such management. The quality of the block positioning determines not only the accuracy
of the final hull, but also the productivity and cost at the erection stage. We have previously proposed the basic concepts
of computer-aided accuracy management. Accuracy management activities consist of "accuracy planning activities" and "accuracy
measurement activities." Accuracy measurement activities involve checking and coping with inaccuracy. We have also proposed
a system of accuracy measurement metrics: one is accuracy for completion (e.g., straightness, flatness), and the other is
accuracy for construction (e.g., the relative joint shapes of each part). This paper explains the detailed accuracy metrics
for a block positioning operation in the erection stage. The quality of the block positioning operation is estimated by this
system: the accuracy of the completed hull can be evaluated by the concept of tolerance, and the accuracy of the construction
process can be evaluated by the concept of labor costs. The prototype of this accuracy metrics system is then implemented.
This metrics system is combined with the optimization software program iSIGHT to decide the best block positioning process.
Then some examples of the block position optimizing process are shown.
Received: November 2, 2001 / Accepted: December 6, 2001 相似文献
34.
本文对奥迪100轿车制动盘半自动平衡去重机的铣削去重精度进行了计算与分析;对去重铣削深度的选取及最大去重铁削角进行了计算,对铣削去重引起的质量误差进行了计算和分析;另外,对整机结构及工作循环过程作了介绍。 相似文献
35.
In this paper, an experimental study on the wall-impinging spray of the slit-type GDI injector is presented. To examine the
effects of various factors on the development of a spray impinging on the wall, experiments were conducted at various injection
pressures, ambient pressures, wall distances from the injector tip, wall temperatures, and wall inclination angles. Behavior
of the impinging spray was visualized using a planar laser scattering method. It is shown that the spray path penetration
of the wall-impinging spray increases with increases in injection pressure, wall distance, wall temperature, or wall angle.
On the other hand, the spray path penetration of the wall-impinging spray decreases with increases in ambient pressure. The
predicted spray path penetration calculated by the empirical equation estimates the spray path penetration in all cases, and
the empirical equation is optimized for the total injection pressure. 相似文献
36.
37.
桩腿是自升式平台的关键部件,其设计强度决定了平台的作业能力及相应环境条件的选取,同时也是平台升降系统选型及其主要性能参数确定的重要依据。本文结合近年来海上风能开发热点,以目前市场上主流的自升式风电安装平台为研究对象,结合其作业及功能特点,综合平台载荷工况特征及强度要求,针对桩腿截面型式的选取,内部环筋加强结构、桩腿桩靴连接区域结构设计及插销孔的强度分析等关键技术进行深入研究。并从建造流程、精度控制及焊接工艺出发,探讨了板壳式桩腿建造工艺,获得了适用于柱型桩腿设计方法及强度分析工程化方法,为此类结构设计提供重要参考,具有实际工程应用价值。 相似文献
38.
S. Kim J. M. Nouri Y. Yan C. Arcoumanis 《International Journal of Automotive Technology》2009,10(3):277-284
The spray characteristics of a 6-hole injector were examined in a single cylinder optical direct injection spark ignition
engine. The effects of injection timing, in-cylinder charge motion, fuel injection pressure, and coolant temperature were
investigated using the 2-dimensional Mie scattering technique. It was confirmed that the in-cylinder charge motion played
a major role in the fuel spray distribution during the induction stroke while injection timing had to be carefully considered
at high injection pressures during the compression stroke to prevent spray impingement on the piston. 相似文献
39.
40.
针对铁路机务段喷漆作业特点,在分析了国内外对于大型工件喷漆所采取的通风方式的基础上,结合工厂通风经济、有效、节能的发展方向,提出了上送、下排局部均匀流通风方式。通过对气流合理的组织,有效地控制了污染气体的挥发与扩散,达到了保护工人健康的目的。同时对其技术特点和技术关键问题进行了阐述。 相似文献