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31.
32.
本文论述影响手糊玻璃钢质量的几个因素,同时对控制玻璃钢的质量提出了一些办法,对进一步提高玻璃钢的质量有一定的意义。 相似文献
33.
Earth Observation (EO) sensors play an important role in quantifying biomass burning related fuel consumption and carbon emissions, and capturing their spatial and temporal dynamics. Typically, biomass burning emissions inventories are developed by exploiting either burned area (BA) or active fire (AF) measures of fire radiative energy (FRE). These approaches have both advantages and limitations. For example, methods based on burned area data typically require hard-to-obtain estimates of fuel load and combustion completeness, and the accuracy of the BA algorithm may deteriorate for small fires or those in densely forested terrain. Conversely, ‘raw’ FRE-based methods are typically low-biassed due to the non-detection of low intensity fires, and are also hindered by cloud cover. Here we develop a methodology integrating these two EO data types to deliver a high temporal resolution emissions inventory, maximising the benefit of each data type without requiring additional information. We focus on Africa, the most fire affected continent, and combine daily FRE observations provided by Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) with BA measures delivered by Moderate Resolution Imaging Spectroradiometer (MODIS). For individual fires detected by both types of data, we estimate fuel consumption per unit area (FCA: g·m− 2) via the ratio of FRE-derived total fuel consumption (FCT) to BA. These values are then extrapolated to fires that were mapped using the BA data but which remained undetected in the SEVIRI AF product, thus correcting for the ‘low spatial resolution bias’ inherent in geostationary AF datasets. Calculated daily continental scale FCT for Africa varies between 0.3 and 20 Tg for the period February 2004-January 2005. We estimate annual continental FCT to be 1418 Tg, far closer to the 2272 Tg provided by the widely used Global Fire Emissions Database (version 3; GFEDv3) than is obtained when using ‘raw’ FRE data alone. This synergistic approach has substantially narrowed the gap between GFEDv3 and FRE-derived emissions inventories, whilst the geostationary FRP observations offer the advantage that the daily emissions estimates can be distributed more accurately over the diurnal fire cycle if required for linking to atmospheric transport models. 相似文献
34.
SMC、BMC用于制造汽车的沿革与灿烂前景 总被引:8,自引:0,他引:8
本文介绍了:1.SMC、BMC的优缺点及其汽车制品的种类,几国SMC市场简况;2.汽车制造业采用SMC、BMC的沿革及近况;3.轻质、高强SMC、BMC汽车零件的研制与实例;4.SMC制品的基准产量^[注];5.SMC面临的挑战([注]:SMC制品客观上存在着一个随时间推移而递增的基准产量,低于此基准其本低于同类钢零件,高于此基准时则高于钢零件;1986年和1996年的基准分别为7和15万件/年;目前北美半数以上的SMC公司的产量都低于10万件/年,由此可见SMC的潜力很大)。 相似文献
35.
This paper aims at exploring the effects of anti-seismic reinforcement with the fiber-reinforced polymer (FRP) material bonded to the dam surface in dam engineering. Time-history analysis was performed to simulate the seismic failure process of a gravity dam that was assumed to be reinforced at the locations of slope discontinuity at the downstream surface, part of the upstream face, and the dam heel. A damage model considering the influence of concrete heterogeneity was used to model the nonlinearity of concrete. A bond-slip model was applied to the interface between FRP and concrete, and the reinforcement mechanism was analyzed through the bond stress and the stress in FRP. The results of the crack pattern, displacement, and acceleration of the reinforced dam were compared with those of the original one. It is shown that FRP, as a reinforcement material, postpones the occurrence of cracks and slows the crack propagation, and that cracks emanating from the upstream surface and downstream surface are not connected, meaning that the reinforced dam can retain water-impounding function when subjected to the earthquake. Anti-seismic reinforcement with FRP is therefore beneficial to improving the seismic resistant capability of concrete dams. 相似文献
36.
预应力FRP筋混凝土梁在低周反复荷载下的恢复力模型 总被引:1,自引:0,他引:1
作为一种新型建筑材料,FRP具有轻质、高强、耐腐蚀等优点,非常适合作为预应力筋材料.通过4根预应力FRP筋混凝土梁在低周反复荷载下的试验研究,根据预应力FRP筋混凝土梁在低周反复荷载下滞回曲线的特点,提出了适合于预应力FRP筋混凝土梁的弯矩-曲率恢复力模型,并与试验结果进行了比较,计算模型与试验结果吻合良好。 相似文献
37.
外贴预应力FRP片材加固混凝土梁抗弯承载力计算 总被引:3,自引:0,他引:3
基于已有的试验结果,根据不同情况下的破坏型态,推导了外贴预应力FRP片材的RC梁截面受弯承载力公式,其计算结果与试验值吻合较好.在此基础上,就外贴预应力FRP片材抗弯加固设计方法进行了初步的探讨. 相似文献
38.
The design of reinforced concrete (RC) flexural members such as beams, slabs and columns is intrinsically based on the inherent ductility of the member. In reinforced concrete beams and slabs, ductility is generally achieved by using ‘under-reinforced’ sections and generally governed by the neutral axis depth parameter ku which requires ultimate failure by concrete crushing at a specified strain εc. As the plates of fibre reinforced polymer (FRP) plated RC beams can fracture or debond before the concrete crushes at εc, the ku approach is not directly applicable. Hence, new fundamental approaches and a deeper understanding of ductility are required which are the subjects of this paper. 相似文献
39.
Effect of fiber orientation on the structural behavior of FRP wrapped concrete cylinders 总被引:1,自引:0,他引:1
Guoqiang Li Dinesh Maricherla Kumar Singh Su-Seng Pang Manu John 《Composite Structures》2006,74(4):475-483
In this study, 27 concrete cylinders with a diameter of 152.4 and a height of 304.8 mm were prepared. Among them, 18 cylinders were wrapped using two layers of fiber reinforced polymer (FRP) with six fiber orientations; six cylinders were wrapped using four layers of FRP with fibers in axial or hoop direction only; the remaining three cylinders were used as control. The FRP used was E-glass fiber reinforced ultraviolet (UV) curing vinyl ester. Fifteen coupon specimens were prepared to experimentally determine the tensile strength of the FRP with fibers oriented at 0°, 45°, and 90° from the loading direction. Co-axial compression tests were conducted on the wrapped cylinders and control cylinders. The test results were compared with existing confinement models. It is found that the strength, ductility, and failure mode of FRP wrapped concrete cylinders depend on the fiber orientation and wall thickness. Fibers oriented at a certain angle in between the hoop direction and axial direction may result in strength lower than fibers along hoop or axial direction. A larger database is desired in order to refine the existing design-oriented confinement models. 相似文献
40.
目的阐述FRP筋混凝土的黏结机理。探讨影响FRP筋与混凝土黏结性能的主要因素.方法对84个FRP筋混凝土试件进行中心拉拔试验。总结和分析试验结果,对影响FRP筋与混凝土黏结性能的主要因素进行研究.结果剪切滞后使受拉FRP筋横截面中心与边缘的变形有一定差异,横截面的正应力非均匀分布,使得黏结强度随FRP筋直径的增大而降低.试件的黏结强度随埋深的增加而降低.对于混凝土强度等级大于C15的试件,混凝土强度对黏结强度的影响还难以定论.另外,FRP筋的表面形式和不同类型纤维组成也是影响其与混凝土黏结性能的重要因素.结论FRP筋直径、埋置深度、FRP筋表面形式和类型等均对FRP筋与混凝土之间的黏结性能有重要的影响,而混凝土强度的影响还难以确定,仍需要大量的试验进行验证.试验结果为深入了解FRP筋与混凝土的黏结性能提供了依据. 相似文献