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681.
船用辅助鼓风机(以下简称风机)是在柴油机启动及低速工况为满足扫气系统的要求而附设的一种装置,这种风机与一般离心式通风机有明显不同,在外形尺寸上不仅要满足柴油机的安装要求,在性能上也必须达到给定的A点及B点空气流量和压力以满足柴油机起动及低负荷时对空气量的需求[1]。如何运用一种合理、高效的方法对试验数据的分析,是对风机的设计制造有着十分重要工程应用价值。因此通过运MATLAB可视化编程功能对辅助鼓风机测试数据进行最小二乘法曲线拟合,并对其拟合结果进行了分析, 拟合误差在3% 之内,得到了精准的风机的性能曲线。 相似文献
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本文简要介绍了达克罗防腐技术的发展、特点、防腐机理及工艺流程,对达克罗涂层和电镀锌镀层的性能进行了对比分析和探讨,展望了达克罗防腐技术在舰船电子设备上应用趋势。 相似文献
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This study aims at quantifying the distribution of REEs associated with chemical weathering processes, as well as investigating weathering mechanisms and source regions of the Gaoping (formerly spelled Kaoping) River (KPR) catchment basin located at southwestern Taiwan. Spatial distributions of dissolved rare earth elements, as well as major ions, trace elements and Sr isotopes in river waters were analyzed using SF-ICPMS and TIMS. Our results indicate that REE concentrations and patterns predominantly reflect sources and intensity of chemical weathering along the river's catchment. Most specimens have high Na/Cl (4.2–30.1 mol/mol) ratios due to strong weathering intensity in the upper stream. The Na/Ca and Mg/Ca ratios suggest the main contribution is from weathering of silicates and carbonates. Total concentrations of REEs are rather low in the Gaoping (Kaoping) River (6.7–15.4 ng/L), possibly influenced by adsorption onto suspended particles. The REE patterns also reflect source heterogeneity in weathering minerals with large LREE depletion and MREE enrichment. Europium is strongly enriched in the Gaoping (Kaoping) River water, as a result of its preferential dissolution from suspended particles. Unique Gadolinium anomaly is present in all specimens, likely related to contamination due to clinic waste disposal. Small fractionations of LREE/HREE have occurred along the KPR and can be used as a distinct signature for source identification. The main stream samples exhibit a relatively wide range of 87Sr/86Sr, 0.71265–0.71360, with a systematical increase downstream due to source mixing of dissolved basalt (less radiogenic) and sedimentary rocks. Each tributary shows distinct Sr isotope signatures due to different rock types and ages. These isotopic and elemental compositions provide important information on weathering source and erosion budget. 相似文献
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Microstructure profiling measurements at two locations in the Yellow Sea (a deeper central basin and a local shelf break) were analyzed focusing on tidal and internal-wave induced turbulence near the bottom and in the pycnocline. A classical three-layer density structure consisting of weakly stratified surface and bottom boundary layers and a narrow sharp pycnocline is developed by the end of warm season. Turbulence in the surface layer was not influenced by the tidal forcing but by the diurnal cycle of buoyancy flux and wind forcing at the sea surface. The enhanced dissipation and diffusivity generated by the shear stress at the seafloor was found in the water interior at heights 10–15 m above the bottom with a phase shift of ~ 5–6 m/h. No internal waves, turbulence, or mixing were detected in the pycnocline in the central basin, in contrast to the pycnocline near the local shelf break wherein internal waves of various frequencies were observed all the time. The thickness of the surface layer near the local shelf break slightly exceeded that of the bottom layer (20 vs. 18 m). A 5–6 m high vertical displacement of the pycnocline, which emerged during the low tide, was arguably caused by the passage of an internal soliton of elevation. During this episode, the gradient Richardson number decreased below 0.25 due to enhanced vertical shear, leading to local generation of turbulence with dissipation rates exceeding the background level by an order of magnitude. 相似文献