energetic particle
- energetic particle的基本解释
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[化] 高能粒子
- 相似词
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The main research work of this paper are focused on following areas:(1) Based on review of the theory and methods on measurements of particle fields, a new idea for obtaining particle size and velocity distribution within a spray through imaging the particle field with a laser light sheet was put forward;(2) A DPIV (Digital Particle Image Velocimetry) system, is fit for velocity measurements of low speed flows, was developed and expended to particle size distribution measurement;(3) An arithmetic for particle velocity field reconstruction was developed, and the velocity distribution of water mist was also obtained;(4) A software system for particle analysis, which based on image geometry emend, de-noise and image partition was developed, the parameters such as particle size distribution, mean diameter, number of particles, minimum and maximum diameter can be got with this system;(5) A water mist system was developed and its characteristics, such as droplet velocity, size distribution, number of droplets and spray cone angle under different conditions were obtained from experiments with PIVS;(6) The measurement results of water mist characteristics with PIVS were compared and analyzed with the simply simulated results, and in addition, in order to verify the accuracy of PIVS, some experiments were conducted with the standard particles, such as glass-ball with known mean diameter of 50μm and 115μm, metallic coated tracing particle with mean diameter of 12μm;(7) Some experimental studies on interaction of water mist with liquid pool fires were conducted.
本论文的主要工作包括以下几个方面:(1)在对粒子场测量的相关理论和具体方法进行综述分析的基础上,提出了通过采用激光片光对粒子场进行成像以获取其粒径和速度等参数分布的新思路;(2)研制了适宜于低速流动速度场测量的DPIV(Digital Particle Image Velocimetry)系统,并使其实现了对粒子场粒径分布的测量功能;(3)研制了基于粒子运动轨迹的速度场重建算法,获取了细水雾雾场的速度分布;(4)研制了基于几何校正、去噪、图象分割等图象处理方法的"粒度分析软件系统",该系统既可分析给出粒子场的粒径分布直方图和平均粒径,还可给出粒子的数目以及最大、最小粒径等信息;(5)建立了一细水雾发生系统,并应用上述方法对不同压力条件下细水雾系统的雾场特性(如速度分布、雾滴粒径分布、雾滴的数目、喷雾张角以及雾化长度等)进行了实验测量研究;(6)对细水雾特性参数的PIVS测量结果与计算机简单模拟计算结果进行了定性比较分析,并利用平均粒径为50μm和115μm的玻璃球以及12μm的标准示踪粒子对PIVS系统的粒径和速度测量结果进行了实验验证,同时对其局限性进行了分析讨论;(7)对不同工况条件下细水雾与油池火相互作用的过程进行了模拟实验研究。
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The influences of the shock thickness and Alfven waves on the particle acceleration by diffusive shock waves are numerically studied through solving one-dimensional diffusive equation including the second-order Fermi effect. It is shown that the spectral index of the energetic particles strongly depends on the shock thickness. For example, the spectral index increases from 2.1 to 3.7 in the low energy range of 3-10 MeV and from 2.5 to 5.0 in the high energy range of 20-60 MeV as the thickness increases. The spectral index decreases from 4.3 to 3.1 as the particle injection energy increases. The spectral index decreases from 4.0 to 1.8 at the quasi-steady stage with the enhancement of the compression ratio from 2 to 4. The results indicate that under the influence of Alfven waves, the energetic particle spectrum at lower energy becomes flat and the spectral index decreases from 2.5 to 0.6 in the low energy range of 3-10 MeV and from 11.6 to 5.0 in the high energy range of 20-60 MeV. At the same time, the rollover energy reaches 19.6 MeV. The spectral index decreases from 5.8 to 2.9 as the energy density of Alfven waves increase. All these results are basically consistent with the theoretical models, as well as the observations of typical energetic particle events.
通过数值求解包含二阶费米加速的一维扩散方程,探讨在准平行激波条件下激波厚度和级联阿尔芬波对粒子加速的影响,研究粒子分布函数的演化与激波厚度和阿尔芬波强度的内禀关系,计算结果表明:(1)考虑激波厚度时,谱指数明显依赖于激波厚度,随着厚度从0.32增大到2.56,低能端(3-10MeV)谱指数逐渐从2.1增加到3.7,高能端(20-60MeV)谱指数从2.4增大到5.0,能谱逐渐变软;当初始注入粒子动量增大1.3倍,质子能谱指数从4.3减小到3.1,且与零厚度激波加速的谱指数差值缩小;厚度不变时,随着压缩比从2增加到4,准稳态分布时低能端(3-10MeV)粒子能谱指数逐渐从4.0减小到1.8谱变硬;(2)在级联阿尔芬波的影响下,随着时间的增大,粒子在低能处(3-10MeV)的谱指数从2.5减小到0.6高能端(20-60MeV)谱指数从11.6减小到5.0,能谱变硬,拐点能量值从7.5MeV增大到为19.6MeV;随着波的能量密度增大,谱指数从5.8减小到2.9,这表明阿尔芬波强度越大,加速效率越高,通过与激波厚度解析结果和高能粒子事件的观测能谱比较发现两者是一致的,说明数值模拟结果是可靠的。
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The mainly conclusions in our research are as flowing: tungsten trioxide powders with 100 nm primary particle are obtained by spray drying,calcination and wet milling process, and an average size of quadric particle composed of agglomerated particles is 0.64 μm; tungtsen powders with 39 nm grain size and 60 -100 nm primary particle are produced directly from previous tungsten trioxide using one step reduction in hydrogen at 700℃, and an average size of quadric particle of tungsten powder is 2.91 μm; tungsten trioxide and copper tungstate compound powders with 100 nm - 200 nm primary particle are produced using ammonia metatungsten and copper nitrate as raw materials by spray drying,calcination and wet milling process;the compound powders are transformed completely into tungsten and copper compound powders by reduction in hydrogen at 700℃,in which tungsten grain size is 59 nm and copper grain size is 51 nm; primary particle size of compound powders is 80 - 120 nm,and an average size of agglomerated quadric particle is 1.86 μm; tungsten nitride powders with 35 nm grain size are prepared from tungsten trioxide powders by nitrogen treatment thoroughly in pure ammonia at 650℃, and an average size of agglomerated quadric particle is 0.64 μm in normal temperature.
研究结果表明:采用喷雾干燥—焙烧—球磨工艺可以制备出粒度约为100nm的WO_3粉体,它们在团聚后形成的二次颗粒平均粒度为0.64μm;采用一步直接氢还原方法可在700℃下从上述WO_3粉体制备出晶粒尺寸为39nm的、一次颗粒粒度为60-100nm的W粉体,其二次颗粒的平均粒度为2.91μm;以偏钨酸铵、硝酸铜为原料,采用喷雾干燥—焙烧—球磨工艺可制备出一次粒度为100-200nm的WO_3和CuWO_4混合粉体;采用氢还原工艺可在700℃下将这种粉体完全转变为W、Cu复合粉体,其中W的平均晶粒粒尺寸为59nm,Cu的平均晶粒尺寸为51nm;复合粉体的一次颗粒尺寸为80-120nm,在常温下团聚后形成的二次平均粒度为1.86μm;采用纯氨氮化工艺可以在650℃下由WO_3粉体制得WN,其晶粒尺度为35nm,在常温下团聚后的二次平均粒度为6.4μm。
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energetic particle:高能粒子
这种理论认为,由高能宇宙线产生的高能粒子(energetic particle)大规模簇射,可能触发闪电的大规模能量释放,而这些高能宇宙线则源于一些爆炸的恒星. 要让古列维奇的理论成功运作,必须有大量带电粒子同时通过雷暴,而宇宙线单独产生的大气簇射并不能产生足量的高能粒子.
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energetic particle:高能 子
843 end-use energy efficiency 最终能源效益 | 844 energetic particle 高能 子 | 845 energy 能 ,能
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energetic particle instrument:高能粒子仪器
enemator 灌肠器 | energetic particle instrument 高能粒子仪器 | Energetine 爱那健丁生血固精片
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energetic particle event:高能粒子事件
energetic particle burst 高能粒子爆 | energetic particle event 高能粒子事件 | energetic particle instrument 高能粒子仪器
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energetic particle burst:高能粒子爆
energetic particle 高能粒子 | energetic particle burst 高能粒子爆 | energetic particle event 高能粒子事件
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