共查询到20条相似文献,搜索用时 171 毫秒
1.
利用数值模拟程序模拟了不同高度核爆炸下大气的X射线电离及演化过程.结果表明: X射线电离产生的电子数密度在射线到达后约100 ns时刻达到峰值, 峰值数密度随着到裸核区距离的增加而减小;电子具有较长的寿命, 电子寿命随着到裸核区距离的增加而增大; X射线电离空气产生正离子O+, O2+, N2+,爆高为120 km情况下 O+的峰值数密度与O2+的相近,能维持约1 s. X射线对空气的电离影响范围在数十千米以内,在距裸核区较近的区域, 爆高为80 km时产生的电子峰值数密度比爆高为120 km时的电子峰值数密度高, 在距裸核区较远的区域则相反. 相似文献
2.
对Cl/HN3/I2产生NCl(a)/I激光的过程进行了化学动力学计算,主要考察了Cl,HN3和I2的初始粒子数密度及其配比对小信号增益系数的影响。结果发现,当温度为400K, 初始Cl粒子数密度为1×1015,1×1016和1×1017cm-3时,小信号增益系数分别达到1.6×10-4,1.1×10-3和1.1×10-2cm-1,获得最佳小信号增益系数的HN3和I2的初始粒子数密度分别为初始Cl粒子数密度的1~2倍和2%~4%。同时,对Cl,HN3和I2配比对小信号增益系数和增益持续时间的影响进行了讨论。 相似文献
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6.
在IBM4中,当存在s、d、g玻色子时,体系的对称性群为U(90).本文研究了子群链:U90 U15(sdg)×U6(ST) SU15(sdg)×U6(ST) SU5(sdg)× O6(ST) SO5(dg)×O3(S)×O3(T) O3(dg)×O3(S)×O3(T) O3(J)×O3(T)给出了约化规则和典型能谱,并在轻核中找到了具有这种动力学对称性的能谱的例子,偶偶核34S与奇奇核 34Cl在一个多重态中. 相似文献
7.
运用含Davidson修正的多参考组态相互作用方法,在aug-cc-pVTZ基组水平上,对BeCl分子基态和相同多重度的几个低电子激发态进行了势能扫描计算.通过群论原理确定各电子态对称性及离解极限.将其中基态(X2Σ+)和第一激发态(A2Π})对应的势能曲线拟合到Murrell-Sorbie解析势能函数形式,得到基态(X2Σ+)的离解能及主要光谱常数(括号中为文献[6]提供的实验值)为De=3.74eV,Re=0.18173nm(0.17970),we=857.4cm1(847.2),wexe=5.03cm-1(5.14),Be=0.7103cm-1(0.7285),αe=0.0059cm-1(0.0069),第一激发态(A2Π)的De=3.02eV,Re=0.18369nm(0.18211),we=832.7cm-1(822.1),wexe=5.93cm-1(5.24),Be=0.6953cm-1(0.7094),αe=0.0065cm-1(0.0068),计算结果与实验值符合得较好.另外,通过Level程序求解双原子径向核运动的Schrödinger方程得到J=0时BeCl分子这两个电子态的全部振动能级. 相似文献
8.
研究了电子通量对ZnO/K2SiO3热控涂层光学性能的影响。分别采用通量为5×1011/cm2·s,8×1011/cm2·s,1×1012/cm2·s 和5×1012/cm2·s的电子对试样进行辐照。电子辐照下涂层的光学性能发生了退化,并且发现了退化涂层在空气中的“漂白”现象。分析了ZnO/K2SiO3热控涂层光学性能的退化机制,同时讨论了电子通量对太阳光谱吸收系数的影响。实验结果发现,在5×1011~1×1012/cm2·s的电子通量范围内,电子通量对ZnO/K2SiO3热控涂层光学性能的影响相同。因此在这个电子通量范围内,采用加速地面试验来模拟空间的电子辐照效应是有效的。 相似文献
9.
Data on the absorption coefficient of H2O in binary mixture with N2 in UV region of spectra are presented. With the use of the high sensitivity photoacoustic spectrometer, the following values of the absorption coefficient were found: 2.3×10-9cm-1·Pa-1(λ=255 nm), 0.9×10-9 cm-1·Pa-1(λ=271 nm), and 1.6×10-9cm-1 ·Pa-1(λ=289 nm). 相似文献
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采用零维等离子体动力学模型,计算了不同约化场强条件下N2/O2放电等离子体的演化特性.结果表明,平均电子能量与约化场强有着近似的线性关系,在约化场强为100 Td时,平均电子能量约为2.6 eV、最大电子能量达35 eV;约化场强是影响电子能量函数分布的主要因素.气体放电过程结束后,振动激发态氮分子的粒子数浓度不再变化,电子激发态的氮分子、原子和氧原子的粒子数浓度达到一峰值后开始降低;放电结束后的氧原子通过复合反应生成臭氧.约化场强升高,由于低能电子减少的影响,振动激发态氮分子的粒子数浓度降低,当约化场强由50 Td增加75 Td,100 Td时,粒子数浓度由3.83×1011 cm-3降至1.98×1011 cm-3和1.77×1011 cm-3,其他粒子浓度则相应增大.
关键词:
等离子体
约化场强
粒子演化
数值模拟 相似文献
12.
C. Wang N. Srivastava 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(3):465-477
OH radical number density in multiple atmospheric pressure microwave plasma
jets is measured using UV cavity ringdown spectroscopy of the OH (A–X) (0–0) band at 308 nm. The plasma cavity was excited
by a
2.45 GHz microwave
plasma source and plasma jets of 2–12 mm long were generated by using
three different plasma gases, argon (Ar), Ar/N2, and Ar/O2.
Comparative characterization of the plasma jets in terms of plasma shape,
stability, gas temperature, emission intensities of OH, NO, and N2, and
absolute number density of the OH radical was carried out under different
plasma gas flow rates and powers at various locations along the plasma jet
axis. With three different operating gases, the presence of OH radicals in
all of the plasma jets extended to the far downstream. As compared to the
argon plasma jets, the plasma jets formed with Ar/N2 and Ar/O2 are more diffuse and less stable. Plasma gas temperatures along
the jet axis were measured to be in the range of 470–800 K for all of the
jets formed in the different gas mixtures. In each plasma jet, OH number
density decreases along the jet axis from the highest OH density in the
vicinity of the jet tip to the lowest in the far downstream. OH density
ranges from 1.3 × 1012 to 1.1 × 1016, 4.1 ×
1013 to 3.9 × 1015, and 7.0 × 1012 to 4.6
× 1016 molecule/cm3 in the Ar, Ar/N2, and Ar/O2
plasma jets, respectively. The OH density dependence on plasma power and gas
flow rate in the three plasma jets is also investigated. 相似文献
13.
Early afterglows of N2 and N2‐O2 flowing microwave discharges are characterized by optical emission spectroscopy. The N and O atom and N2(A) metastable molecule densities are determined by optical emission spectroscopy after calibration by NO titration for N‐atoms and measurements of NO and N2 band intensities for O‐atoms and N2(A) metastable molecules. By using N2 tanks with 50 and 10 ppm impurity, it is determined in the afterglow an O‐ atom impurity of 150‐200 ppm. Variations of the N and O‐atom and N2(A) metastable molecule densities are obtained in the early afterglow of N2–(9·10–5–3·10–3)O2 gas mixtures. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The integral energy spectrum of primary cosmic rays has been obtained. In the energy range (2.4×103−1.1×105 GeV), the spectrum of all nuclei is consistent with a power law of indexγ=1.55±0.06 and the flux of all nuclei is:N(⩾E
0)⋍(5.1±1.8)×10−1×E
0
−1.55
particles/cm2 sterad. sec., whereE
0 is in GeV. The spectrum of primaryα-particles in the energy range (4.4×103−4.8×104) GeV is also consistent with a power law of indexγ=1.71±0.12 and the flux is:N(⩾E
0)=(4.2±1.4)×10−1×E
0
−1.71
, particles per cm2 sterad. sec, whereE
0 is in GeV. 相似文献
16.
A microwave (2.45 GHz) oxygen discharge (3 hPa, 150 W, 50 mL.min–1) is studied by optical emission spectroscopy of O(5P) (line 777.4 nm) and of the atmospheric system of O2(head‐line 759.4 nm). Calibration of the spectral response of the optical setup is used to determine the concentrations of O(5P) and O2(b). The concentration of the O(5P) atoms is in the range 108–109 cm–3 and the concentration of the O2(b) molecules is in the range 1014 – 2 × 1014 cm–3 along the discharge tube. An attempt is made to simulate the experimental results by using coupling the Boltzmann equation, homogeneous energy transfer V‐V and V‐T, heterogeneous reactions on the walls (energy transfer and recombination of atoms) and a kinetic scheme (electronic transfer and chemical reactions). The Boltzmann equation includes momentum transfer, inelastic and superelastic processes and e‐e collisions. V‐V and V‐T transfer equations are obtained from the SSH theory and the kinetic scheme includes 65 reactions with 17 species [electrons e, ions O– and O2–, fundamental electronic neutral species O(3P), O2, O2(X,v), O3 and excited neutral species O2(a), O2(b), O2(A), O(1D), O(1S), O(5P), O(4d 5Do), O(5s 5So), O(3d 5Do) and O(4s 5So)]. A fair agreement between experimental results and modelling is obtained with the following set of fitting values: – heterogeneous deactivation coefficient for O2(b) γ = 2.6 × 10–2; – rate constant of reaction [O(1D) + O(3P) → 2 O(3P)] k34 = 1.4 × 10–11 cm3.s–1; – electron concentration in the range 1010 – 1011 cm–3. Modelling shows that the recombination coefficient for oxygen atoms on the silica wall (range 1.4 × 10–3 – 0.2 × 10–3) is of the same order as the values obtained in a previous paper and that the ratio ([O] / 2 [O2]initial) is about 33–50%. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
17.
采用静电探针技术对微波电子回旋共振(MW-ECR) 等离子体进行了诊断,利用等离子体增强 非平衡磁控溅射(PE-UMS)法在常温下制备了Zr-N薄膜, 通过EPMA,XRD,显微硬度对膜的 结构和性能进行评价.实验结果表明,随氮气流量增加,总的等离子体密度从807×109c m-3增加到831×109cm-3然后逐渐减小为752×10 9cm-3;而N2+密度则从312×108< /sup>cm-3线性递增到335×109cm-3;电子温度变化 不大.对薄膜而言,随N2+密度增大,样品中氮含量增加,而晶粒逐 渐变小,当样品中N/ Zr原子比达到14时,薄膜中出现亚稳态的Zr3N4相以及非晶相, 在更高氮流量下,整 个薄膜转变为非晶态.与此相应,薄膜硬度由最初的225GPa增大到2678GPa 然后逐渐减 小到1982GPa.
关键词:
氮化锆薄膜
ECR等离子体
磁控溅射
诊断 相似文献
18.
We have determined the temperature dependence of σ1 of 129Xe in oxygen gas. These results were obtained by measurement of the resonance frequency of 129Xe in gas samples of known densities in Xe and O2. The shift of the resonance frequency due to Xe-Xe interactions has been measured in pure Xe gas samples with improved precision. This allows the determination of σ1(Xe-O2) by subtracting out the known effect of Xe-Xe interactions in mixed Xe-O2 samples. σ1(Xe-O2) values are reported here for the temperature range 220 to 440 K. The values of σ1(Xe-O2) are adequately described by the polynomial function in p.p.m. amagat-1 σ1(Xe-O2) = - 1·061 + 3·64 × 10-3τ - 2·19 × 10-5τ2 + 9·58 × 10-8τ3 - 2·08 × 10-10τ4, where τ = (T - 300 K). It is found that the temperature dependence of σ1(Xe-O2) can be interpreted in terms of a contact interaction between Xe and the paramagnetic O2 molecule. 相似文献
19.
N. Tomašovičová M. KONERACKÁ P. Kopčanský M. Timko V. Závišová 《Phase Transitions》2013,86(6-7):595-603
We studied the structural transitions in ferronematics based on the thermotropic nematic liquid crystal MBBA (4′ -methoxybenzylidene-4-n-butylaniline) having a nematic-to-isotropic transition temperature T N–I?=?48.0○C and in MBBA-based ferronematics doped with a magnetic suspension consisting of Fe3O4 particles (10?nm in diameter) coated with oleic acid as a surfactant. The ferronematic samples were prepared with different volume concentrations of magnetic particles φ?=,1× 10?4, 2× 10?4 and 5×10?4. The temperature dependences of the critical magnetic fields in a bias electric field under strong applied magnetic fields are presented. We calculated the surface density of anchoring energy W at the nematic–magnetic particle boundary. Scaling of the structural transition in the MBBA and MBBA-based ferronematics with the temperature of the nematic-to-isotropic transition was observed. 相似文献
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Starting with the definition of quaternion gauge theory, we have undertaken the study of SU(2)
e
×SU(2)
m
×U(1)
e
×U(1)
m
in terms of the simultaneous existence of electric and magnetic charges along with their Yang-Mills counterparts. As such,
we have developed the gauge theory in terms of four coupling constants associated with four-gauge symmetry SU(2)
e
×SU(2)
m
×U(1)
e
×U(1)
m
. Accordingly, we have made an attempt to obtain the abelian and non-Abelian gauge structures for the particles carrying simultaneously
the electric and magnetic charges (namely dyons). Starting from the Lagrangian density of two SU(2)×U(1) gauge theories responsible for the existence of electric and magnetic charges, we have discussed the consistent theory
of spontaneous symmetry breaking and Higgs mechanism in order to generate the masses. From the symmetry breaking, we have
generated the two electromagnetic fields, the two massive vector W
± and Z
0 bosons fields and the Higgs scalar fields. 相似文献