共查询到18条相似文献,搜索用时 93 毫秒
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分析了国内LNG汽车发展状况,以410 l公交车用LNG燃料罐为例,进行内部介质热力过程分析,计算得到了燃料罐内压力变化曲线。 相似文献
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通过高速录像对3种量级(5、20、50 kg)FAE装置的静爆实验进行了现场记录,通过对燃料爆炸抛撒形成云雾的成长过程的实时记录结果,把燃料的爆炸抛撒过程分为3个阶段:喷出阶段、过渡阶段和膨胀阶段,其依据是爆炸驱动力和气动阻力的相互作用而导致的云雾径向膨胀速度的变化;对于结构相似的FAE装置,爆炸抛撒各阶段结束时刻及最终的云雾直径与装填燃料量的立方根成正比,说明小型装置可以模拟大型FAE武器;此外对应于不同阶段结束时刻的云雾直径与装置直径的比值分别为5.5、30和45。 相似文献
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空浴式汽化器基础传热问题及研究现状评述 总被引:1,自引:0,他引:1
对我国空浴式汽化器的研究和使用现状进行了评述;分析了空浴式汽化器涉及的流动沸腾、凝华结霜、自然对流等传热过程及各过程之间的相互耦合关系;提出了综合研究各传热过程及相互制约关系的新思路,拟在前期工作的基础上研究管内的汽液两相流及沸腾传热过程、管外的霜层生长及导热规律,以及翅片管内外的耦合传热规律. 相似文献
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Phase-change contrast agents (PCCAs) consist of liquid perfluorocarbon droplets that can be vaporized into gas-filled microbubbles by pulsed ultrasound waves at diagnostic pressures and frequencies. These activatable contrast agents provide benefits of longer circulating times and smaller sizes relative to conventional microbubble contrast agents. However, optimizing ultrasound-induced activation of these agents requires coordinated pulse sequences not found on current clinical systems, in order to both initiate droplet vaporization and image the resulting microbubble population. Specifically, the activation process must provide a spatially uniform distribution of microbubbles and needs to occur quickly enough to image the vaporized agents before they migrate out of the imaging field of view. The development and evaluation of protocols for PCCA-enhanced ultrasound imaging using a commercial array transducer are described. The developed pulse sequences consist of three states: (1) initial imaging at sub-activation pressures, (2) activating droplets within a selected region of interest, and (3) imaging the resulting microbubbles. Bubble clouds produced by the vaporization of decafluorobutane and octafluoropropane droplets were characterized as a function of focused pulse parameters and acoustic field location. Pulse sequences were designed to manipulate the geometries of discrete microbubble clouds using electronic steering, and cloud spacing was tailored to build a uniform vaporization field. The complete pulse sequence was demonstrated in the water bath and then in vivo in a rodent kidney. The resulting contrast provided a significant increase (>15 dB) in signal intensity. 相似文献
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多无人机协同系统的过度扩散会引起协同失效, 对系统进行规模控制是解决该问题的一种潜在方法. 首先抽象出多无人机协同搜索系统的宏观运动特征, 进而建立平台的运动方程, 然后通过构造合适的李雅普诺夫函数, 获得该系统的稳定控制规律及其控制参数. 仿真结果表明: 1)本文所提的稳定控制机制不仅能够使多无人机系统实现有效的协同, 还能确保系统的稳定性; 2)在系统稳定时, 通过调整相关控制参数可以有效地控制系统规模.
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无人机
协同系统
稳定控制 相似文献
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蓄压型液舱用于沿海LNG运输的研究 总被引:1,自引:0,他引:1
提出了解决沿海液化天然气运输的一种方案。针对小型LNG船的关键设备蓄压型独立液舱存储液化天然气,进行了理论计算和模拟试验,并对影响液舱压力和运输时间的主要因素进行了研究分析。对LNG运输的时间进行预测,论证了该种小型LNG船在近海或沿海运输的可行性,为开发用于近海运输的小型LNG船,提供了理论依据。 相似文献