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利用局部综合法对非零正传动弧齿锥齿轮副进行大重合度加工参数设计,克服了非零正传动由于啮合角增大而使得重合度降低的不足。通过实例与常规设计的结果进行仿真与应力分析对比,结果表明,在同样的载荷条件下,新设计比常规设计的小轮最大齿根拉伸应力减小27.6%,最大齿根压缩应力减小23.5%,最大齿面接触应力减小6.5%,同时大轮的齿根应力也有所降低,使得齿轮副具有更高的寿命和可靠性。 相似文献
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The test of functional groups of microorganisms in Spiral Up-flow Reactor System and the correlation between microorganisms in the water and the main environmental factors are studied.The results show that the diversity of microorganisms population in the SUFR system is complex and the bio-community formed in the SUFR system is stable.The close relations between abundance of bacteria and nutrients are found.The correlation between heterotrophic bacteria and COD is 0.949.The correlation between organic phosphate bacteria and TP is 0.815. The correlation between nitrosobacteria and NH_3-N is 0.909. The correlation between disnitrifier bacteria and TN is 0.653. 相似文献
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Neiger R Simpson KW 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2000,14(2):125-133
The discovery of the spiral bacterium Helicobacter pylori and its causative role in gastric disease in humans has brought a dramatic change to gastroenterology. Although spiral bacteria have been known for more than a century to infect the stomachs of dogs and cats, recent research has been conducted mainly in the wake of interest in H. pylori. H. pylori has not been found in dogs and only very rarely in cats and zoonotic risk is minimal. A variety of other Helicobacter spp. can infect the stomach of pets; however, their pathogenic role is far from clear, and they have a small but real zoonotic potential. The prevalence of gastric Helicobacter spp. in dogs and cats is high, irrespective of clinical signs, and as in human medicine, mode of transmission is unclear. The relationship of Helicobacter spp. to gastric inflammation in cats and dogs is unresolved, with inflammation, glandular degeneration, and lymphoid follicle hyperplasia accompanying infection in some but not all subjects. Circulating anti-Helicobacter immunoglobulin G antibodies have been detected in 80% of dogs with naturally acquired infection and most dogs and cats with experimental infection. The gastric secretory axis is similar in infected and uninfected cats and dogs and no relationship of infection to gastrointestinal ulcers has been found. Differences in the pathogenicity of Helicobacter spp. are apparent, because infection with H pylori is associated with a more severe gastritis than infection with other Helicobacter spp. in both cats and dogs. Rapid urease test, histopathology, and touch cytology are all highly accurate invasive diagnostic tests for gastric Helicobacter-like organisms in dogs and cats, whereas culture and polymerase chain reaction are the only means to identify them to the species level. Urea breath and blood tests or serology can be used to diagnose Helicobacter spp. noninvasively in dogs and cats. Most therapeutic studies in pets have not shown long-term eradication of Helicobacter spp. Whether this is due to reinfection or recrudescence has not been established. 相似文献
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螺旋型喷嘴雾化及流量特性实验 总被引:3,自引:1,他引:3
分析了几种常用的表征液滴尺寸的参数以及喷嘴的流量及雾化特性,用因次分析的方法建立并回归了TF型喷嘴的雾化准则关系式。通过实验研究了TF6喷嘴的几种雾化液滴直径随喷雾压力变化的规律,建立了TF6喷嘴的流量与喷雾压力之间的关联式。实验表明,随着喷雾压力的升高,喷嘴的流量增大,雾滴的各种直径均降低,但喷雾压力对雾滴直径的影响是有限度的。 相似文献
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