共查询到20条相似文献,搜索用时 281 毫秒
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估算了预混固体自蔓延层流燃烧合成(SCS)中自烧温度和着火温度时的反应进度,给出了一个更附合实际的燃烧温度和反应进度的分布模型和一个改进后的SCS能量方程,由此推导出ZrB2燃烧合成过程中的温度分布函数.该分布函数在95%的燃烧反应阶段与实验相符.分析了在高温端偏离较大的原因.
关键词: 相似文献
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在分析Grüneisen γ近似函数的适用范围和热力学γ高压演化特性的基础上, 根据Grüneisen γ系数的物理性质和变化特点, 利用数学分析的方法建立了Grüneisen γ通用函数γn(v). 将γn(v)代入热力学函数γ(v, T), γ(v, T)即成为全压力区连续可导的函数, 并由γ(v, T)直接导出了等熵温度函数TS(v); 再根据等熵温度与Hügoniot 温度的函数关系获得了Hügoniot温度方程的解析函数TH(v), 从而使Hügoniot方程成为完全物态方程. 对几种金属做了检验, 由等温方程推算Hügoniot方程, 或者由Hügoniot方程推算等温方程, 其结果都与实验符合得很好. 相似文献
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本文对具有双δ函数速度分布的相对论性电子束,考察了其环形平衡性质。通过对反环径比展开,得到了关于磁通函数及电势的一级近似解析解。还讨论了电子漂移轨道的近似描述。
关键词: 相似文献
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研究了由光子增减叠加操作作用于相干态而得量子态的非经典性及其在热环境中的退相干问题.通过解析导出了Mandel's Q参数、光子数分布、Wigner函数等,讨论其非经典性.研究表明一阶光子增减相干叠加相干态在相空间总是取负值,只要满足条件∣2z* +α-α*∣2<1.基于Wigner函数的演化积分公式,解析地推导出了在热环境中Wigner函数的简洁表达式.研究首次表明:如果κt<1/2ln[(2(η)+2)/(2(η)+1)]得以满足,一阶光子增减相干叠加相干态在相空间最小值点处Wigner函数分布总存在负部.此外,根据Wigner函数负部体积讨论了其非经典特性. 相似文献
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引入一个新的能量分布函数,利用该能量分布函数与粒子速度分布函数耦合来求解一个热流场. 因而,这一能量分布函数与粒子速度分布函数和Boltzmann方程构成了一个新的格子Boltzmann模型. 这一模型满足质量、动量和能量守恒的准则. 用该模型对垂直平板间的狭缝热对流进行了数值模拟,数值结果表明,在Prandtl数为1,Grashof数在1.3×102—1×106之间时,流场将出现多个旋涡结构的流型. 得出了与Lee相一致的结论.
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能量分布函数
Boltzmann方程
热对流 相似文献
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采用密度泛函理论确定La2与Lan F(n=1,2)分子的电子与结构特性.应用最小二乘法拟合出La2和LaF分子的Murrell-Sorbie势能函数,在此基础上推导出光谱数据和力常数.基态La2F分子具有C2v对称性的弯曲结构,电子态4A2,结合能为7.89 eV.用多体项展式理论得出La2 F的解析势能函数,其等值势能图准确再现了La2 F分子的平衡结构. 相似文献
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介绍了一种测量高温的蓝宝石光纤温度计.蓝宝石单晶光纤由于其极好的高温物理化学性能,适用于高温下光纤测温应用,可用作辐射型光纤温度传感器.蓝宝石光纤温度计采用激光加热小基座法生长出端部掺Cr3+的蓝宝石光纤荧光温度传感头.用激光加热小基座,把对荧光有温度反应的材料如红宝石晶体光纤生长在蓝宝石光纤上,制成具有结构紧凑,耐高温,功能稳定的传感探头.通过荧光寿命的检测,可以测量所对应的温度.根据表面温度,可以依据温度场得到内部温度,用于测量连铸炉中的中间包钢水温度,并给出了温度计的实验系统以及原始实验数据.实验数据表明,此结果精度高,可实现非接触测量. 相似文献
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We present experimental results for a silicon thermometer (p+-p-n+ device placed between the poles of a permanent magnet) with a frequency output. Measurements were made for temperatures in the range 77–335 K. When the temperature increases from 77 K to 335 K the device sensitivity decreases from 40 kHz/K to 3.1 kHz/K for a pulsed operating voltage of 65 V. The device sensitivity can be controlled through the operating voltage. We analyze the basic properties of thermometer element using the theory of the bulk helical instability of the semiconductor plasma. We compare its performance parameters with those of previously known devices with frequency outputs.V. D. Kuznetsov Siberian Physico-technical Institute at Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 48–53, February, 1995. 相似文献
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A low temperature Mössbauer thermometer suitable for the 25 to 250 mK temperature range with151Eu in EuS as the absorber has been discussed, and the problems of absorber thickness have been pointed out. The large correction for the apparent temperature deduced from the sum of Lorentzian analysis has been given for absorbers with a different number of resonance nuclei per cm2. With the correction procedure, without a least-squares fit using the transmission integral, one can obtain the temperature with an accuracy of better than ±2%. 相似文献
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P. Napolitani K. -H. Schmidt P. Armbruster A. S. Botvina M. V. Ricciardi L. Tassan-Got F. Rejmund T. Enqvist 《Physics of Atomic Nuclei》2003,66(8):1471-1477
The high-resolution spectrometer FRS at GSI, Darmstadt, provides the full isotopic and kinematical identification of fragmentation residues in relativistic heavy-ion collisions. Recent measurements of the isotopic distribution of heavy projectile fragments led to a very surprising new physical finding: the residue production does not lose memory of the N/Z of the projectile ending up in a universal deexcitation corridor; an ordering of the residues in relation to the neutron excess of the projectile has been observed. These unexpected features can be interpreted as a new manifestation of multifragmentation. We have found that, at the last stage of the reaction, the temperature of the big clusters subjected to evaporation is limited to a universal value. The thermometer to measure this limiting temperature is the neutron excess of the residues. 相似文献
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K. Lefmann J. T. Tuoriniemi K. K. Nummila A. Metz 《Zeitschrift für Physik B Condensed Matter》1997,102(4):439-447
We have utilized both neutron transmission and neutron diffraction to measure the spin polarization in a single crystal of 109Ag, whereby the nuclear spin temperature could be obtained. Transmission of a polarized neutron beam provides an accurate and convenient primary thermometer. The feasibility of unpolarized neutron transmission was demonstrated as well. The diffraction measurements were strongly influenced by extinction, whence this method had to be calibrated against another thermometer. In this way we obtained information about extinction in the crystal. 相似文献
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研制了可用于大型爆炸现场的、 测量爆炸火焰真温的多光谱温度计(量程为800~3 500 ℃,波长范围为0.6~1.1 μm)。测量原理进一步改进,加入亮温逼近法解决了二次测量法初值选取困难的问题,并应用此高温计在空旷场地对3 kg TNT炸药爆炸的全过程进行测量。通过实验结果的分析可知,此高温计可以测量爆炸火焰真温变化全过程,对波阵面瞬时温度与燃烧火球温度的测量均具有很好的效果。同时,分析了影响此高温计测量精度的各个因素,得出目前制约多光谱高温计测量精度提高的主要因素仍然为真温算法及标定方法的误差,这为今后研制高精度高温计明确了方向。 相似文献
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W. Clauss A. A. Il'yukhin D. N. Kozlov V. V. Smirnov O. M. Stel'makh K. A. Vereschagin 《Applied physics. B, Lasers and optics》1996,62(3):279-285
In this work, we present the results of two-wavelength (2)-CARS thermometry of hydrogen at temperatures from 300–1200 K. The choice of the pair of spectral lines for the 2-CARS thermometer with respect to optimal temperature sensitivity within a given temperature range was analysed. Software was developed to process the experimental data and calculate the temperature. In the experiments, temperature and density were measured in a heated cell using single-shot and averaged CARS intensities in the pure rotationalS branch. The accuracy achieved and its dependence on measured temperature values and on the number of averaged shots was analysed.The sponsoring of this work by the Stabsabteilung Internationale Beziehungen at the Kernforschungszentrum Karlsruhe under project number RUS 222.12 is gratefully acknowledged 相似文献
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Helmut Quast Markus Heubes Anita Dunger Hans-Heinrich Limbach 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,134(2):236-244
The first carbon-13 shift thermometer for the temperature range of 100–300 K is based on the very rapid equilibration of a pair of semibullvalene valence tautomers. The temperature dependence of the equilibrium constant is reflected in strongly temperature-dependent shift differences Δδ between averaged signals, e.g.,d(Δδ)/dT= 0.051 ppm K−1at 300, 0.087 ppm K−1at 200, and 0.175 ppm K−1at 110 K for the quaternary carbon atoms C2 and C6. At 37 temperaturesT, which were measured with calibrated platinum resistance thermometers, shift differences Δδ were taken from nondecoupled carbon-13 spectra recorded from solutions of 1 in mixtures of chlorodifluoromethane and deuterated dimethyl ether without spinning. The least-squares fit of these Δδ vsTdata to a polynomial equation of the fourth degree (Eq. [5],r2= 0.9999) allows the calculation of temperatures from measured shift differences with a standard deviation of 0.46 K and an estimated error of about 1 K. The heating effects of WALTZ-16 decoupling and the influence of solvents on Δδ are investigated. A comparison with existing NMR thermometers demonstrates the superior performance of the new carbon-13 shift thermometer with respect to precision and the accessible temperature range. 相似文献