共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
K. Kodera 《Space Science Reviews》2006,125(1-4):319-330
This paper reviews the solar influence on climate through stratospheric dynamical processes. There are two possible processes,
both being a consequence of the wave-mean flow interaction in the upper stratosphere. One involves changes in the vertical
propagation of planetary waves and the resultant tropospheric circulation change in the extratropics of the winter hemisphere.
The other involves change in the global meridional circulation in the stratosphere and associated convective activity change
in the tropics. These processes have been discussed on an 11-year solar cycle, but they are also applicable for centennial-scale
solar influence on climate. 相似文献
3.
《中国航空学报》2023,36(5):96-124
In the aerospace industry, integrated aluminium alloy plates and stiffened panels with high accuracy and performance attract significant interest. To manufacture these panels as integrity with high accuracy, multiple processes need to be utilised, such as machining, welding and forming. During the whole manufacturing chain, residual stresses can be generated and redistributed in the components among different processes. The residual stress would significantly affect the shapes and properties of the final products. Currently, these great effects are not well considered in the design and manufacturing processes. This paper aims to draw a general understanding of the residual stress generated in the pre-manufacturing processes and its effects on subsequent manufacturing processes. The mechanisms and distributions of residual stresses generated in typical pre-manufacturing processes of structural panels, including machining, welding and additive manufacturing (AM), are firstly summarised. The detailed effects of generated residual stresses on distortion and application properties in subsequent manufacturing processes are then concluded. In addition, current methods developed for the investigation of residual stress effect in multi-processes manufacturing are critically reviewed, including experimental, analytical, finite element (FE) and machine learning methods. Furthermore, the future development trend of methods for residual stress consideration and control in the design of manufacturing processes is summarised, providing comprehensive guidance to achieve the high accurate manufacturing of aluminium alloy structural components. 相似文献
4.
J. Birn A. V. Artemyev D. N. Baker M. Echim M. Hoshino L. M. Zelenyi 《Space Science Reviews》2012,173(1-4):49-102
This paper deals with acceleration processes in the magnetotail and the processes that enhance particle precipitation from the tail into the ionosphere through electric fields in the auroral acceleration region, generating or intensifying discrete auroral arcs. Particle acceleration in the magnetotail is closely related to substorms and the occurrence, and consequences, of magnetic reconnection. We discuss major advances in the understanding of relevant acceleration processes on the basis of simple analytical models, magnetohydrodynamic and test particle simulations, as well as full electromagnetic particle-in-cell simulations. The auroral acceleration mechanisms are not fully understood, although several, sometimes competing, theories and models received experimental support during the last decades. We review recent advances that emphasize the role of parallel electric fields produced by quasi-stationary or Alfvénic processes. 相似文献
5.
6.
W. E. Krumbein 《Space Science Reviews》2008,135(1-4):81-94
Earth as a planet under firm control of life processes since more than 3 Ga has evolved global biogeochemical cycles, biogeomorphogenetic processes and structures also called plates or global tectonics including global climate and movement of water masses. These processes have deep impact on the shape and thickness of continental land masses as well as the chemistry and mineralogy of the crust and upper mantle. Biogenerated rock structures in this sense can be visualised through the analysis of sedimentary rock structures exhibiting e.g., biogenerated stromatolites, onkolites, oolites or cementing structures of sandstones which clearly preserve biochemical processes and biophysical structures. Further the chemical composition including the segregation of mineral layers, ore deposits, sedimentary and metamorphic rocks and granites hint to sun powered energy storage (gas, gas hydrates, hydrocarbons, coal) and tectonic processes initiated or at least modified through the enormous input of external energy through reduced carbon and iron compounds. One can state with considerable reliability that a planet under control of life must exhibit rock chemistry, mineralogy and structures typical for the impact of life on the geodynamic cycles. This includes the idea of top-down geotectonics instead of bottom-up processes. 相似文献
7.
W. H. Matthaeus G. P. Zank R. J. Leamon C. W. Smith D. J. Mullan S. Oughton 《Space Science Reviews》1999,87(1-2):269-275
Mechanisms for the deposition of heat in the lower coronal plasma are discussed, emphasizing recent attempts to reconcile
the fluid and kinetic perspectives. Structures at the MHD scales are believed to act as reservoirs for fluctuation energy,
which in turn drive a nonlinear cascade process. Kinetic processes act at smaller spatial scales and more rapid time scales.
Cascade-driven processes are contrasted with direct cyclotron absorption, and this distinction is echoed in the contrast between
frequency and wavenumber spectra of the fluctuations. Observational constraints are also discussed, along with estimates of
the relative efficiency of cascade and cyclotron processes.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
对聚酰亚胺泡沫材料的性能、合成方法、生产工艺、用途等进行了综述,并对今后的研究方向进行了展望。 相似文献
9.
10.
11.
贾新朝%陈兆生%卢焰 《宇航材料工艺》2001,31(6):55-57
研究了新型无钴超高强度钢G50经不同锻造比墩粗锻造后材料的组织及性能的变化情况,并检验该新材料随锻造及热变形的能力。结果表明,该新材料具有非常好的可锻性及热成形性,且不同锻造比锻造并按标准制度热处理后的性能相差不大。 相似文献
12.
对TCAS的原理分析 总被引:2,自引:0,他引:2
刘岩 《中国民航学院学报》1994,12(1):35-44
本文基于对防撞基本概念的理解,分析了TCAS工作原理,并结合实际工作过程进行了论证。 相似文献
13.
介绍了自动扫描磨粒形态分析仪运动系统的设计、关键技术的解决途径及制造过程中的关键工艺问题的研究成果. 相似文献
14.
农民工权利法律保护的回顾与基本思路 总被引:1,自引:0,他引:1
杨红朝 《郑州航空工业管理学院学报(管理科学版)》2010,(2):127-131
农民工是我国城乡二元社会经济体制下,改革开放政策推动产生的一个特殊的社会群体。文章回顾了我国农民工权利法律保护的演变历程,对农民工权利缺损进行了实证分析,提出了农民工权利法律保护的基本思路,农民工权利法律保护是一个系统工程,应当遵循一个基本理念,坚持两个基本原则,从立法、执法和司法环节上构建有机的农民工权利法律保护体系。 相似文献
15.
运八起落架上采用耐久性设计更改的分析 总被引:2,自引:0,他引:2
介绍了运八起落架延寿过程中采用了耐久性设计典型范例11项,实施于起落架设计的改进和制造。包括:高强度钢构件的注油嘴、管状结构件、高应力花键镀铬表面在镀前进行喷丸、U形接头防腐措施、采用光弹修形控制应力水平、采用喷丸强化、重要模压件表面加工、重要焊接件焊缝加工、采用防氧化处理、改进防腐措施等。经过疲劳试验验证,其效果是极其显著的。 相似文献
16.
L. J. Lanzerotti 《Space Science Reviews》1983,34(3):347-356
Plasma physics processes, whose ultimate origin is the Sun, exist in the Earth's magnetosphere and ionosphere and can produce effects which are detrimental to the operation of technological systems associated with long conductors deployed on the Earth's surface. Geomagnetic fluctuations produced by such plasma processes can cause disturbances and disruptions in cable communication systems, electrical power distribution systems, and long pipelines. This paper briefly addresses these three topics with illustrative examples of some measured effects from each topic area. 相似文献
17.
在耗散结构理论和 DMM方法的基础上,提出一种确定锻造热力参数范围的方法,以获得组织和性能稳定一致的锻件。详细叙述了用所提出的方法确定 GH1 69合金锻造热力参数范围的过程,并提供了对研究 GH1 69合金锤上和压力机上锻造过程有实用价值的曲线 ;提出为获得优质 GH1 69合金锻件,以采用中等应变速率的设备和较低的锻造温度为宜 相似文献
18.
19.
循环微粒(细胞外囊泡)在血管调节、炎症、凝血、细胞增殖与凋亡等生物过程中具有细胞间传递信息的功能。 所含成分复杂多样,与心血管疾病的发生发展过程联系紧密。循环微粒(细胞外囊泡)未来可以作为反映凝血功能、炎症反应、组织器官损伤的临床标志物,或者是调控血管稳态、纠正凝血、改善内环境、保护组织器官功能的临床治疗靶点,具有重要的研究意义。本文总结循环微粒(细胞外囊泡)在心血管外科领域的相关研究进展,讨论循环微粒(细胞外囊泡) 在相关疾病过程中所起的作用,及其在相关疾病诊断与治疗当中的研究及应用前景。 相似文献
20.
This review attempts to present an integrated view of the several types of solar cosmic ray phenomena. The relevant large and small scale properties of the interplanetary medium are first surveyed, and their use in the development of a quantitative understanding of the cosmic ray propagation processes summarised. Solar cosmic ray events, in general, are classified into two phenomenological categories: (a) prompt events, and (b) delayed events. The properties of both classes of events are summarised. The properties considered are the frequency of occurrence, dependence on parent flare position, the time profile, energy spectra, anisotropies, particle species, velocity dispersions, etc. A single model is presented to explain the various species of delayed event. Thus the halo and core events, energetic storm particle events, EDP events and proton recurrent regions are suggested to be essentially of common origin. The association of flare particle events with electromagnetic phenomena, including optical, X-ray and microwave emissions is summarised. The conditions in a sunspot group, and solar flare that are considered to be conducive to cosmic ray acceleration processes are discussed. Considerable discussion is devoted to physical processes occurring near the Sun. Near Sun particle storage, and diffusion, and secondary injection processes that are triggered by a far distant solar flare are reviewed. In order to explain the considerable differences between aspects of the prompt and delayed events, we propose selective diffusion processes that only occur at early times in a solar flare. The type IV radio emissions at metric wave-lengths are suggested to yield direct evidence for the storage processes that are necessary to explain the properties of the delayed events, and also as yielding direct evidence of secondary injection processes. We conclude by briefly summarising the ionospheric effects of the solar cosmic radiation. 相似文献