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101.
交通标志识别(Traffic Sign Recognition,TSR)是智能交通系统的重要研究方向之一。因道路交通的环境复杂、交通标志数据库规模大小等因素制约,在设计TSR系统可行性方案时必须考虑算法的复杂度、识别率和鲁棒性。针对这一问题,本文提出了一种不同尺度的双通路跃层卷积神经网络算法,在同一通路上交通标志的底层局部特征和高层全局的特征,与不同通路上经过局部响应归一化和池化后的特征在全连接层融合,从而丰富了交通标志分类的特征,最后将特征图输入分类器进行交通标志识别。采用德国交通标志识别标准数据集(German Traffic Sign Recognition Benchmark,GTSRB)进行训练和测试,本文算法的识别率达到97.96%,明显优于单一通路的跃层卷积网络算法和人工方法。 相似文献
102.
为了更好地探究好氧颗粒污泥处理汽车涂装废水的机理,利用好氧颗粒污泥的降解特性得到最佳处理工艺和有机物去除效果,本试验采用动态吸附和静态吸附的方式分别研究了好氧颗粒污泥对汽车涂装废水中有机污染物的初期吸附特性、吸附类型及温度和pH对吸附能力的影响。研究结果表明,好氧颗粒污泥对汽车涂装废水中有机污染物具有一定的初期吸附现象,30 min内COD被快速去除,去除率达到66.62%,180 min后基本趋近于平稳,COD去除率为80.61%。在温度为35℃、pH为7.0时,吸附吸附量最大,且过程是一个以物理吸附、生物吸附、化学吸附三者共同作用的复杂过程。准二级动力学模型能较好地表征吸附机理。 相似文献
103.
104.
《International Journal of Rock Mechanics and Mining Sciences》2007,44(5):647-676
Ground shock in rock masses is created by dynamic events such as rock-bursts, coal bumps or man-made explosions. This article examines two aspects of the phenomenology: the propagation of ground shock, and its effects on underground structures. Numerous experiments, at all scales, as well as numerical modeling clearly show that geologic discontinuities have a large influence on ground shock propagation through their actions as wave-guides or as decoupling features. Three-dimensional discrete element (DE) numerical models provide additional insights into the dynamic response of underground structures as influenced by joint orientation, joint spacing, characteristics of the loading pulse (duration, peak velocity, peak displacement), and repeated loadings. It is also shown that in hard rocks the deformability of rock blocks has a negligible influence on tunnel dynamic structural response compared to that of the joint sets or bedding. When viewed together with pictures of underground failures, the 3-D DE models are shown to capture quite well the kinematics of jointed rocks, and their power is illustrated through a very large simulation of an underground facility under dynamic loading. 相似文献
105.
106.
《Journal of aerosol science》1999,30(2):131-138
The ternary nucleation of an ideal mixture of three alcohols and a non-ideal mixture of water, ammonia and hydrochloric acid, which is relevant in atmosphere, have been investigated theoretically. In the ideal mixture of three alcohols, the nucleation rates obtained using simplified kinetic approach are compared with the nucleation rates given by a detailed kinetic model. The simplified model is seen to underestimate nucleation rates by 2–3 orders of magnitude. This is mainly due to the crude estimate for the Zeldovich factor in the simplified model. We have proposed a modification to the simplified model. The improved model gives order-of-magnitude estimates for the nucleation rates. The ternary nucleation of water–ammonia–hydrochloric acid is studied with the improved model. The results have been compared with binary nucleation of water and ammonium chloride. The results show that water–ammonia–hydrochloric acid mixture is effectively a two-component system. 相似文献
107.
《International Journal of Hydrogen Energy》2020,45(27):13929-13938
Durability and cost of Proton Exchange Membrane fuel cells (PEMFCs) are two major factors delaying their commercialization. Cost is associated with the price of the catalysts, while durability is associated with degradation and poisoning of the catalysts, primarily by CO. This motivated us to develop tungsten-carbide-oxide (WxCyOz) as a new non-carbon based catalyst support for Pt–Ru–based anode PEMFC catalyst. The aim was to improve performance and obtain higher CO tolerance compared to commercial catalysts. The performance of obtained PtRu/WxCyOz catalysts was investigated using cyclic voltammetry, linear scan voltammetry and rotating disk electrode voltammetry. Particular attention was given to the analysis of CO poisoning, to better understand how WxCyOz species can contribute to the CO tolerance of PtRu/WxCyOz. Improved oxidation of COads at low potentials (E < 0.5 V vs. RHE) was ascribed to OH provided by the oxide phase at the interfacial region between the support and the PtRu particles. On the other hand, at high potentials (E > 0.5 V vs. RHE) CO removal proceeds dominantly via OH provided from the oxidized metal sites. The obtained catalyst with the best performance (30% PtRu/WxCyOz) was tested as an anode catalyst in PEM fuel cell. When using synthetic reformate as a fuel in PEMFC, there is a significant power drop of 35.3 % for the commercial 30% PtRu/C catalyst, while for the PtRu/WxCyOz anode catalyst this drop is around 16 %. 相似文献
108.
《International Communications in Heat and Mass Transfer》1995,22(2):235-240
A comparison between the predictions from a previously derived non-dimensional fire growth model and experimental data obtained from a series of fire experiments in a scale (0.4 m cube) compartment is made. Both the qualitative and quantitative types of theoretical behaviour appear to be in reasonable agreement with those found experimentally. 相似文献
109.
为了研究聚酯纤维掺量与盐分对沥青混合料水稳定性的影响,制作聚酯纤维掺量为0、0.1%、0.2%、0.3%的马歇尔试件,在SYD-0713型沥青混合料单轴压缩试验机上进行冻融劈裂试验,研究不同聚酯纤维掺量的沥青混合料浸泡在不同浓度硫酸盐溶液中水稳性的变化规律.试验结果表明:在硫酸盐溶液浓度相同时,随着聚酯纤维掺量的增加,沥青混合料的劈裂抗拉强度及冻融劈裂抗拉强度比均呈现先上升后下降的趋势,说明聚酯纤维掺量存在最佳值,为0.2%,此时水稳性最好.在聚酯纤维掺量相同时,水稳性随硫酸盐溶液浓度的增加呈下降趋势. 相似文献
110.
采用基于动态范围调整的方法,并适当地把图像最亮和最暗附近很少量灰度级像素点滤除,对图像灰度进行线性展宽,实现图像灰度动态范围的自动调整,提高图像的对比度。实验结果表明,该方法可有效地滤除在灰度边界值附近的灰度干扰,图像的质量和对比度明显提高,图像的亮区和暗区的细节都有明显增强,而且处理速度快,鲁棒性好。 相似文献