共查询到19条相似文献,搜索用时 218 毫秒
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将环型横向剪切干涉仪置于两个镜头之间,由此设计出一种新型的离焦4f差分干涉仪,该干涉仪同时具有分离光路的剪切量和条纹空间频率分别可调的优点以及共光路结构的稳定性和易于调节的优点,使得在测量大密度梯度等离子体的密度分布时,可以在不降低空间分辨率的条件下仍保证干涉条纹可读。在DPF装置上进行了实验,获得了等离子体壳层的干涉图样,计算了等离子体的径向电子密度分布,在内电极端面上方测量到的最高电子密度约为1.2×1019 cm-3,外围等离子体壳层的电子密度约为2×1018 cm-3。 相似文献
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采用氧等离子体氧化刻蚀工艺,制备出尖锐的六硼化镧(LaBLaB6)微尖锥场发射阵列。在二极管结构中测试了LaB6-FEAs的场发射性能,得到了真空度为5×10-5 Pa 下的I-V曲线及相应的Fowler-Nordheim节点。结果表明,由于LaBLaB6材料较低的逸出功,使得阴极的开启电压较小,开启场仅为7 V/μm。此外,将氧等离子体氧化刻蚀方法与氩氧等离子体刻蚀方法和电化学刻蚀方法进行了比较,表明氧等离子体氧化刻蚀方法是制备LaB6场发射阴极阵列的一种理想工艺。 相似文献
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为了准确诊断真空中微波等离子体喷流的电子数密度,利用统一的发射和单郎缪尔探针测量等离子体的空间电位,再测量等离子体的电流-电压特性曲线.根据空间电位测量结果,在等离子体的电流-电压特性曲线上能准确地获取饱和电流,从而处理出电子数密度.最后的诊断实验表明,当真空环境压强为2—6 Pa、等离子体发生器以60 W以下的微波功率击穿流量范围是42—106 mg/s的氩气时,所产生的微波等离子体喷流中电子数密度分布在1×1016—7.2×1016/m3范围内. 相似文献
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诊断电子回旋共振离子源等离子体的传统方法是采用传统的单探针无发射时测量伏安曲线,并根据曲线的拐点由理论公式计算出的等离子体密度。本文设计并研制了等离子体密度的测量装置。采用单根朗缪尔探针(该探针可以用来发射电子)测量等离子体的伏安特性。在探针有发射和无发射两种状态下测量得到两条伏安曲线,根据这两条曲线的"分叉点"得到等离子体电位,然后根据该电位直接由计算机计算出电子温度、电子密度。采用该新方法,测量得到的等离子体参量空间电位约为17 V,悬浮电位约为-5 V,电子温度约为4.4 eV,离子密度为1.10×1011cm-3,与传统方法计算出的等离子体1.12×1011cm-3相比,两者相差仅1.8%,但新方法效率和精度更高。 相似文献
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通过考察各种放电状态及气流条件下发生器内外物种的自发辐射谱,发现光谱峰值强度与对应物种浓度成正比。分析了主要的等离子体动力学过程,了解了单重态氧及其它物种的浓度变化规律。考察了α放电和γ放电两种不同的放电方式。发现在α放电状态下,体系中有较少氧原子等淬灭性粒子,更有利于O2(1Δ)产生。加入He,有效地降低了气体体系的离子化阈能和约化场强,约化场强最小时,产生的O2(1Δ)浓度最大,相较于纯氧放电,O2(1Δ)浓度提高一倍以上。考察了腔外各物种浓度的变化,O2(1Δ)离开放电腔后浓度稳定,沿距离减少较慢,有益于出光。优化了本系统的放电极间距,极间距太大或太小,都不利于单重态氧的产生。 相似文献
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青蒿素是一种优异的抗疟药,广泛用于临床医学. 但由于青蒿素天然来源的限制,青蒿素的化学合成一直受到高度关注. 二氢青蒿酸是合成青蒿素的关键前体. 二氢青蒿酸与单线态氧反应形成过氧化物是青蒿素光化学制备中的关键步骤,制约着青蒿素化学合成的产率. 然而关于二氢青蒿酸与单线态氧反应的重要动力学信息并未有报道. 本文通过光敏化法产生单线态氧,研究二氢青蒿酸与单线态氧之间的反应速率常数. 通过直接检测单线态氧在1270 nm处的发光衰减动力学,得出单线态氧与二氢青蒿酸在不同溶剂中的反应速率常数分别为:在CCl4中为1.81×105 (mol/L)-1·s-1,在CH3CN中为5.69×105 (mol/L)-1·s-1,DMSO中为3.27×106 (mol/L)-1·s-1. 发现在三种溶剂中二氢青蒿酸与单线态氧的反应速率常数随着溶剂极性的增加而增加. 这些结果为优化青蒿素光化学合成的实验条件提供了基础知识,有助于提高青蒿素的合成效率. 相似文献
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Polyimide (PI) and Fluorinated Ethylene Propylene (FEP) samples (15 mm×15 mm×50 μm ) were exposed to atomic oxygen ions of average energy ~12 eV and flux ~5×1013 ions cm ?2 s ?1, produced in the Electron Cyclotron Resonance (ECR) plasma. The energy and the flux of the oxygen ions at different positions in the plasma were measured by a retarding field analyzer. The fluence of the oxygen ions was varied from sample to sample in the range of ~5×1016 to 2×1017 ions cm ?2 by changing the irradiation period. The pre- and the post-irradiated samples were characterized by the weight loss, Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), and Fourier Transform Infrared (FTIR) techniques. The weight of the PI and FEP samples decreased with increasing the ion fluence. However, the erosion yield for the PI is found to be higher, by almost a factor five, when compared with that of FEP. On the surface region of irradiated samples, the concentrations of the carbon, fluorine, and oxygen and their corresponding chemical bonds have changed appreciably. Moreover, blisters and nanoglobules were also observed even at a fluence of ~1017 ions cm ?2. This oxygen ion fluence is almost two orders of magnitude lower than that of the 5 eV atomic oxygen, which a satellite encounters in the space, at the low Earth orbit, during its mission period of about 7 years. 相似文献
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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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利用红外光学材料ZnSe和金属Ag在室温下采用电子束蒸发镀膜技术研制了透明导电薄膜ZnSe/Ag/ZnSe,该薄膜的电子浓度为1.208×1020 cm-3,电子迁移率和电阻率分别为17.22 cm2 V-1 s-1和2.867×10-5 Ω·cm,功函数达到5.13 eV,在可见区的平均透过率理论模拟值超过80%,而测量结果为63.8%,测量的最高透过率为83%.结果表明,该透明导电薄膜具有良好的光学和电学性能,可作为透明电极应用于发光二极管等光电子器件中. 相似文献
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C. G. Jin T. Yu Z. F. Wu F. Wang M. Z. Wu Y. Y. Wang Y. M. Yu L. J. Zhuge X. M. Wu 《Applied Physics A: Materials Science & Processing》2012,106(4):961-966
Al-doped zinc oxide (AZO) films are prepared on quartz substrates by dual-ion-beam sputtering deposition at room temperature
(∼25°C). An assisting argon ion beam (ion energy E
i
=0–300 eV) directly bombards the substrate surface to modify the properties of AZO films. The effects of assisted-ion beam
energy on the characteristics of AZO films were investigated in terms of X-ray diffraction, atomic force microscopy, Raman
spectra, Hall measurement and optical transmittance. With increasing assisting-ion beam bombardment, AZO films have a strong
improved crystalline quality and increased radiation damage such as oxygen vacancies and zinc interstitials. The lowest resistivity
of 4.9×10−3Ω cm and highest transmittance of above 85% in the visible region were obtained under the assisting-ion beam energy 200 eV.
It was found that the bandgap of AZO films increased from 3.37 to 3.59 eV when the assisting-ion beam energy increased from
0 to 300 eV. 相似文献
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It is suggested to generate cold ion beams by laser collimation and subsequent laser ionization of a primary atomic beam. The primary beam, formed by a standard method, is collimated through transverse cooling by resonance laser radiation. Laser radiation is also used for the multistep ionization of atoms in the collimated beam. Advantages of the proposed method are a low scatter of the initial ion energy (below 10?1 eV) and a high emittance in the region of the virtual source (~10?6 cm rad at a beam current on the level of microamperes). The high monochromaticity of the obtained ion beam allows the chromatic aberration effect to be significantly suppressed, which implies good prospects for using such sources in ion beam lithography. The proposed method also allows the spectrum of elements used in ion beam sources to be expanded, which is an independent technological advantage. 相似文献
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An intense, essentially photon free, helium metastable beam has been used to cause electron ejection from the clean, oxygen and sulphur covered Ni(100) surface, in a system equiped with an AES facility to monitor surface cleanness. The ejected electron energy distribution obtained for the clean Ni(100) surface is narrow and peaked at ~2 eV, unlike the distribution obtained from INS studies, and consequently indicates different de-excitation mechanisms for incident ions and excited atoms. The ejected electron distribution from the adsorbate covered surface is also narrow, but peaked at ~1 eV with structure which is essentially independent of the nature of the adsorbate. The yield of ejected electrons is found to increase linearly with coverage of both oxygen and sulphur, in contrast to the results obtained from INS. These data indicate that Auger neutralization does not occur at the surface; the possibility of Auger de-excitation is considered. 相似文献
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用密度泛函理论的B3LYP方法,对铀原子采用14个价电子的准相对论有效原子实势及(6s5p2d4f)[3s3p2d2f]收缩价基集合,碳、氧原子采用6311G全电子基集合,应用Gaussian98程序对一氧化碳气体与铀表面相互作用的可能分子结构CUO(角形Cs和线形C∞v构型)分子进行几何优化计算,得到了稳定结构的几何构形、能量、谐振频率、力学性质和电性质,并用微观可逆性原理分析了其可能的离解极限.结果表明,势能函数等值势能面图能清晰地再现CUO分子的结构特征和离解能;铀原子与一氧化碳的反应是势垒较低、容易进行的反应
关键词:
CUO
密度泛函理论
分子结构
势能函数 相似文献
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Baranga A.B.-A. Qi N. Hammer D.A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1992,20(5):562-567
The plasma produced by a 10 cm×6 cm planar flashboard has been investigated by emission spectroscopy. The plasma composition, density, and temperature have been determined with time and space resolution using measurement of the relative intensity of spontaneous emission in different atomic and ionic transitions together with calculations based on a collisional-radiative equilibrium model. The (1-2)×1013 cm-3 and (3-4) eV plasma flows away from the flashboard surface at a speed of about 10 cm/μs. A 1.7 cm/μs transverse velocity has been obtained from the Doppler width of an emission line 相似文献
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An alkali metal atomic beam source for the 6–4000 eV energy range is described. The fast atomic beam is obtained by the neutralization of an alkali ion beam and is detected by surface ionization on an unheated filament. The processes involved in collisions of fast alkali atoms with a tungsten surface are investigated and the behaviour of the atoms is compared with the behaviour of the corresponding ions. 相似文献