共查询到19条相似文献,搜索用时 140 毫秒
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将大气近似为范德瓦尔斯气体,用多方过程取代等温过程,推导出范德瓦尔斯气体处于多方过程时的气压公式,该式是对理想气体恒温气压公式的一种很好的修正. 相似文献
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KrF激光在SF_6气体中受激布里渊散射的研究 总被引:2,自引:1,他引:1
用线宽0.5cm ̄(-1)、脉宽23ns的KrF激光(248nm)在低气压SF_6气体中进行受激布里渊散射(SBS)的实验研究。测量了SBS反射率随泵浦光能量、气体气压、透镜焦距等实验条件的变化关系,分析和讨论了气体气压、透镜瑞利范围对SBS阈值的影响。 相似文献
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可调谐二极管激光吸收光谱技术测量气体浓度时,由于测量氛围温度变化的影响引起解调的二次谐波信号发生变化,最终导致浓度测量的较大误差. 为了修正温度变化对浓度反演结果的影响,适应工业测量、燃烧诊断的需要,采用通过实验所得温度关系的数值拟合修正方法即经验公式修正和根据HITRAN数据库参数的理论关系即理论公式修正两种方法进行分析与讨论. 实验中采用在50 cm长的高温管式炉中通入高温安全的21%浓度的 氧气为目标测定气体,选定760.77 nm的中心吸收波长,测量了温度变化范围为300–900 K,间隔50 K的情况下所得到的谐波信号,并利用一次谐波比值消元法消除光强波动影响后的结果,得出了不同温度下未修正的原始浓度值和通过修正方法后的修正值. 实验结果表明所述的经验公式和理论公式两种修正方法对温度影响都有一定的抑制作用,可以应用到温度变化引起的气体浓度误差修正监测中,为下一步开展燃烧诊断实时在线监测提供了依据.
关键词:
可调谐二极管激光吸收光谱 (TDLAS)
温度修正
经验公式
理论公式 相似文献
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基于速度调制分子离子光谱技术,提出并实现了分别通过研究分子离子光谱强度随母体分子气压变化以及光谱线宽随放电电流变化两条途径对气体放电等离子体中电场的两种光谱不介入诊断方法,两者所获得的电场吻合较好,表明速度调制分子离子光谱方法对等离子体诊断具有十分重要的意义。 相似文献
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利用幅值约220 kV、脉宽约4 ns的高压纳秒脉冲源,对高压氮气亚纳秒气体开关放电特性进行了实验研究。实验结果表明:当气压在3~10 MPa间变化,间隔距离在0.6~1.2 mm间变化时,氮气间隙击穿电压随气压和间隙距离的增大而增大,并随气压的增大略呈饱和趋势,最高击穿电场约为2 MV/cm。开关输出电压波形的上升时间变化范围为145~190 ps,该上升时间随气压、击穿电场以及间隙距离增大而减小。 相似文献
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研究了强激光辐照碳/碳复合材料靶材引起的烧蚀现象及蒸气压对烧蚀速率的影响。基于傅里叶定律,建立了强激光辐照靶材的热传导模型,模拟了忽略蒸气压影响时烧蚀速率随功率的变化;通过Mott-smith近似方法描述了Knudsen层间断区域,分析了间断两侧表面粒子状态参数;结合质量连续方程和蒸气压与温度关系方程,并由气体状态方程描述蒸气流状态,对蒸气压条件下激光烧蚀碳/碳复合材料靶材的速率随功率变化的关系进行了数值模拟。结果表明,在高能激光对靶材的烧蚀过程中,蒸气压力变化会导致靶材的饱和蒸气温度发生变化,进而影响烧蚀速率且使其随功率呈非线性变化,与忽略蒸气压作用时的线性变化规律相差较大,从理论上解释了忽略蒸气压导致的实验数据与理论结果的差异。 相似文献
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George
Livadiotis 《等离子体物理论文集》2020,60(9):e202000041
The paper derives the complete formulations of polytropic behaviour for plasmas described by kappa distributions. This is achieved by employing both positive and negative types of phase-space kappa distributions of a Hamiltonian for a nonzero potential energy, while the cases of positive and negative potential energies are analysed separately. Then, we develop the general polytropic-barometric formula that describes the profiles of density, temperature, and thermal pressure. Furthermore, it is shown how the kappa and polytropic indices can be derived from observational measurements of the temperature altitude gradient. As an example, we calculated the kappa κ ≈ 3.35 and polytropic γ ≈ 0.74 indices of the terrestrial atmosphere at ∼100 km, revealing the existence of heating processes that add thermal energy to atmospheric particles. 相似文献
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Parker’s hydrodynamic isothermal solar wind model is extended to apply for a more realistic polytropic gas flow that can be caused by a variable extended heating of the corona. A compatible theoretical formulation is given and detailed numerical and systematic asymptotic theoretical considerations are presented. The polytropic conditions favor an enhanced conversion of thermal energy in the solar wind into kinetic energy of the outward flow and are hence shown to enhance the acceleration of the solar wind, thus indicating a quicker loss of the solar angular momentum. 相似文献
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A. A. Dubinova 《Technical Physics》2009,54(2):210-213
The exact explicit barometric formula is derived for a warm isothermal Fermi gas in a uniform potential field. 相似文献
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GuoXiang Ai PeiXuan Sheng JinLin Du YongGuang Zheng XianDe Cai HaiTao Wu YongHui Hu Yu Hua XiaoHui Li 《中国科学G辑(英文版)》2009,52(3):376-383
This work describes the barometric altimetry as virtual constellation applied to the Chinese Area Positioning System (CAPS),
which uses the transponders of communication satellites to transfer navigation messages to users. Barometric altimetry depends
on the relationship of air pressure varying with altitude in the Earth’s atmosphere. Once the air pressure at a location is
measured the site altitude can be found. This method is able to enhance and improve the availability of three-dimensional
positioning. The difficulty is that the relation between barometric pressure and altitude is variable in different areas and
under various weather conditions. Hence, in order to obtain higher accuracy, we need to acquire the real-time air pressure
corresponding to an altimetric region’s reference height. On the other hand, the altimetry method will be applied to satellite
navigation system, but the greatest difficulty lies in how to get the real-time air pressure value at the reference height
in the broad areas overlaid by satellite navigation. We propose an innovational method to solve this problem. It is to collect
the real-time air pressures and temperatures of the 1860 known-altitude weather observatories over China and around via satellite
communication and to carry out time extrapolation forecast uniformly. To reduce data quantity, we first partition the data
and encode them and then broadcast these information via navigation message to CAPS users’ receivers. Upon the interpolations
being done in receivers, the reference air pressure and temperature at the receiver’s nearby place is derived. Lastly, combing
with the receiver-observed real air pressure and temperature, the site’s altitude can be determined. The work is presented
in the following aspects: the calculation principle, formulae, data collection, encoding, prediction, interpolation method,
navigation message transmission together with errors causes and analyses. The advantages and shortcomings of the technique
are discussed at the end.
Supported by the National Basic Research Program of China (Grant No. 2007CB815500), the National High Technology Research
and Development Program (Grant No. 2004AA105030), the Pilot Project of the Knowledge Innovation Program of the Chinese Academy
of Sciences (Grant No. KGCX1-21), and the National Natural Science Foundation of China (Grant No. 10453001) 相似文献
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