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1.
采用激光拉曼光谱仪和扫描电子显微镜对以C2H2+H2和C2H2+C3H8+Ar为反应气体,通过直流加热化学气相沉积工艺在SiC纤维表面制备的碳涂层的微观结构及断口形貌进行了研究。结果表明,两种碳涂层的拉曼光谱中1 350,1 400~1 500和1 600cm-1附近均观察到D,D"和G特征峰的存在。碳涂层具有类似石墨的片层结构,结构中微晶的排列显示出一定的无序性,并含有少量非晶态碳。随着沉积温度的升高,微晶尺寸有所增加,结构中的均匀性和有序度也得到改善。断口观察发现,采用C2H2+H2制备的碳涂层平整、致密;而由C2H2+C3H8+Ar得到的碳涂层呈曲折的层片状。分析表明,这主要与结构中的有序度和均匀性有关。  相似文献   

2.
胡梅  刘新国  谭瑞山 《物理学报》2014,63(2):23402-023402
基于我们最近所构建的Ar+H+2→ArH++H(12A′)反应的新势能面,采用准经典轨线法研究了碰撞能分别为0.48,0.77,1.24 eV以及能量为0.48 eV时反应物不同振动态下Ar+H+2→ArH++H反应的立体动力学性质.结果显示在给定的碰撞能情况下,以及当反应物振动量子数由0变到2时计算的积分反应截面与实验值符合得较好.通过比较发现,碰撞能对此反应k-j′关联函数P(θr)分布的影响大于其受振动激发的影响,并且关于k-k′-j′三矢量相关的函数P(?r)分布以及极化微分反应截面对碰撞能较敏感,同时发现振动激发对P(?r)分布和极化微分反应截面也有较大的影响.  相似文献   

3.
Cs(8S -4F)-Ar,H2的碰撞能量转移   总被引:2,自引:2,他引:0       下载免费PDF全文
利用脉冲激光器双光子激发Cs-H2(或Ar)样品池中的Cs原子至8S态,研究了Cs(8S)+M→Cs(4F)+M ,(M= H2,Ar)碰撞能量转移和Cs(4F)+H2→CsH+H反应过程,建立了二能级模型的速率方程组。在不同的Ar密度下测量直接8S→6P与敏化4F→5D积分荧光强度比,得到8S→4F转移速率系数5.3×10-12cm3s-1和4F态的猝灭速率系数4.4×10-13cm3s-1。用相同的方法测得Cs-H2中8S→4F的转移速率系数为1.0×10-9cm3s-1,而4F态的猝灭速率系数1.3×10-10cm3s-1比Cs-Ar中大得多,它是反应与非反应速率系数之和。利用实验数据确定非反应速率系数为8.3×10-11cm3s-1,得出Cs(4F)与H2的反应截面为(2.0±0.8)×10-16cm3s-1。与已有的其它实验结果比较,Cs各激发态与H2的反应活动性顺序为7P>4F>6D>8S。  相似文献   

4.
K2NaAlF6:Ce3+和KAlF4:Ce3+磷光体的光谱特性   总被引:3,自引:0,他引:3  
张吉林  洪广言 《发光学报》1991,12(3):224-229
采用高温固相反应法,在Ar气氛中,合成了K2NaAlF6和KAlF4基质化合物.分别测定了它们的结构,并计算了晶胞参数.测定了K2NaAlF6:Ce3+和KAlF4:Ce3+磷光体的激发光谱和荧光光谱,根据Ce3+的光谱结构的特点,讨论了Ce3+的取代格位.  相似文献   

5.
测量了Tm∶YVO4 晶体的吸收光谱 ,以 34 6nm、36 3nm(1D2 )、475nm(1G4 )、6 98nm (3 F2 ,3 F3 )和 80 1nm(3 H4 )光激发时的发射光谱 ,以及位于 45 4nm (1D2 → 3 F4 )、475nm (1G4 → 3 H6)、6 46nm (1G4 → 3 F4 )、80 6nm(3 H4 →3 H6)的荧光谱线的激发光谱 ,对测量的结果进行了详细分析 ,解释了离子能级间的跃迁过程。提出了Tm∶YVO4 晶体基质与Tm3 + 之间的能量交换的概念和新的跃迁通道 ,证实了存在1D2 +3 H6→1G4 +3 F4 以及1G4 +3 H6→3 H4 +3 H5的能量传递过程 ,还可能存在交叉弛豫过程 1G4 +3 H6→3 F2 +3 F4 。这些过程使得Tm∶YVO4 晶体难以实现1D2 能级上转换发光 (4 5 4nm左右 ) ,但 475nm的上转换发光 (1G4 →3 H6)较强 ,3 F4 能级是潜在红外激光发射能级。  相似文献   

6.
应用拉曼光谱法对氘气在不同条件下的谱峰信噪比进行了实验研究。采用32mW功率的Ar+激光器(514nm),通过石英玻璃管,研究了光栅、激光功率、曝光时间和气体压强对氘气拉曼谱图信噪比的影响,得出了氘气拉曼光谱信噪比与激光功率、曝光时间和气体压强呈正比关系。绘制出适用于本套实验仪器的不同压力与信噪比的标准曲线,并用三组随机样品对关系式SNR(J2→2)=10.6×10-4 p+1.271 34进行验证。当氘气压强为21 280Pa时,相对误差是4.8%,并且当压强增大到67 235Pa时,相对误差下降到1.46%。  相似文献   

7.
在托卡马克偏滤器区域充入杂质气体是检验偏滤器杂质屏蔽效应的重要手段。利用快速极紫外EUV光谱仪对EAST托克马克装置上开展的偏滤器Ar杂质注入实验进行观测。结合NIST原子光谱数据库对2~50 nm范围内不同电离态Ar的线光谱进行了谱线识别,识别出ArⅣ,ArⅨ-Ⅺ,Ar XⅣ-XⅥ等若干个电离态的谱线。为了同时观测等离子体不同区域的Ar杂质行为,在杂质注入实验时重点监测Ar XⅥ35.39 nm(Ar XⅥ电离能918.4 eV,主要分布在等离子体芯部)和ArⅣ44.22 nm(ArⅣ电离能9.6 eV,主要分布在等离子体边界)这两条谱线。利用该两条谱线强度随时间演化的结果初步分析了偏滤器杂质屏蔽效应。在同一充气口不同等离子体位形下的实验结果表明偏滤器对于从偏滤器区域注入Ar杂质的屏蔽效果优于从主等离子体区域注入,并且下偏滤器及内冷泵的综合粒子排除能力优于上偏滤器。  相似文献   

8.
本文研究了四-(对-羧基苯基)卟啉(TCPP)在H2O/CF3COOH、H2O/CCl3COOH和H2O/CH3COOH溶液中的UV-Vis吸收光谱、荧光光谱和拉曼光谱.实验表明,TCPP在H2O/CH3COOH和H2O/CCl3COOH溶液中以分子态的N-质子化卟啉H8TCPP2+存在,而在H2O/CF3COOH中则形成H8TCPP2+的J-聚集体.J-聚集体显示,UV-Vis吸收光谱和荧光光谱的谱带明显红移.拉曼光谱表明,J-聚集体中H8TCPP2+分子的排列与N-质子化四-(对-磺酸基苯基)卟啉H4TSPP2-的J-聚集体相似.  相似文献   

9.
在矩形截面的爆轰管道中,对C2H2+2.5O2+8.17Ar和C2H2+5N2O在CJ爆轰状态下经过不同楔面所发生的马赫反射的影响因素进行了实验研究。实验中,由烟膜记录爆轰波马赫反射的胞格结构转变过程;采用纹影技术捕捉爆轰波马赫反射波阵面的不稳定性及波后流场分布。实验结果表明:两种实验气体在爆轰波马赫反射过程中均存在由CJ区域向过驱区域转变的胞格结构;初始压力对楔面与马赫反射三波点轨迹线之间的夹角(χ)影响明显,楔角θw对χ的影响随θw的增大而增大;根据实验测得的θw+χ与θw之间的关系,可知爆轰波马赫反射三波点轨迹线的斜率随着θw的增大而增大,与CJ区域内胞格轨迹线的相交距离也更短,使马赫杆后的过驱度升高。另外,不稳定气体C2H2+5N2O的不稳定性高于稳定气体C2H2+2.5O2+8.17Ar,导致二者的爆轰波马赫反射行为存在较大的差异。  相似文献   

10.
以4-溴-1,8-萘酐为原料合成了新型萘酰亚胺衍生物N-正己基-4-苄胺基-1,8-萘酰亚胺(HBN),通过NMR和 MS 表征了其结构。利用荧光光谱研究它对铁离子(Ⅲ)的识别作用。实验显示,在 C2 H5 OH/H2O (φ:1/1)体系中,当Fe3+浓度为4×10-7~1×10-2 mol·L-1时,HBN荧光强度随Fe3+浓度增加大幅度下降。线性回归方程为:F0/F=623.2532cFe3++0.9642(R2=0.9963)。常见金属离子,如Ca2+,Na+, Cu2+,Zn2+,Pb2+,Co2+,Ni2+,Mn2+及Fe2+等,均不干扰HBN对Fe3+的识别。结果表明,HBN对Fe3+具有较好的选择性和灵敏度。  相似文献   

11.
Fully biodegradable poly(L-lactide) and poly(ethylene succinate) (PLLA/PES) blends were prepared via melt-blending using PLLA and PES as reactants in a stainless steel chamber. The prepared PLLA/PES blend, as well as neat PLLA and PES, was characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD) to confirm the structure and the crystallization of PLLA in the blend. The mechanical properties of PLLA/PES blends were determined by bending and tensile tests and the effects of PES content on the mechanical properties of PLLA/PES blends were investigated. It was found that blending some amount of PES could significantly improve the elongation at break while still keeping considerably high strength and modulus. With increasing PES content, both strength and modulus gradually decreased; however the elongation at break significantly increased. SEM was used to examine the morphology of fracture surfaces of PLLA/PES blends.  相似文献   

12.
In this research, firstly sulfonation of polyethersulfone (PES) was carried out and then polyethersulfone (PES)/sulfonated polyethersulfone (SPES) blend membranes were prepared with phase inversion induced by immersion precipitation technique. polyvinylpyrrolidone (PVP, 2 wt% concentration) was added in the casting solution as pore former. SPES was characterized by FT-IR and UV-visible spectra, ion exchange capacity and swelling ratio. The characterization of SPES polymer indicates that the sulfonic acid groups were produced on PES polymer. Also, the prepared PES/SPES blend membranes were characterized by contact angle, AFM, SEM and cross-flow filtration for milk concentration. The contact angle measurements indicate that the hydrophilicity of PES membrane is enhanced by increasing the SPES content in the casting solution. The SEM and AFM images show that the addition of SPES in the casting solution results in a membrane with larger surface pore size and higher sub-layer porosity. The mean pore size of the membrane increased from 98 nm for PES membrane to 240 and 910 nm for 50/50 and 0/100 PES/SPES blend membranes, respectively. The pure water flux and milk water permeation through the prepared membranes are increased by blending PES with SPES. Moreover, the protein rejection of PES/SPES blend membranes was lower than PES membrane.  相似文献   

13.
Bulk sensitivity is inevitable for photoelectron spectroscopy (PES) when one studies bulk electronic structures of strongly correlated electron systems, which are often much different from surface electronic structures. Combination of soft and hard X-ray PES (SXPES and HAXPES) is a promising approach for this purpose by quantitatively evaluating the contribution of the surface in the observed angle integrated PES spectra. Even in the angle resolved PES studies (ARPES), the bulk sensitivity of the SX-ARPES is required to get the real bulk band dispersions and Fermi surface topology, which may be noticeably modified in the surface region as seen in several materials studied in this paper.Although hard X-ray ARPES is feasible, deep attention is required for the discussion of the possible recoil effects for the valence band. Besides, extremely low energy PES (ELEPES) by use of microwave excited Xe, Kr and Ar lamps will be as useful as those by synchrotron radiation and laser to realize a very high resolution of better than 5 meV with bulk sensitivity under certain conditions.  相似文献   

14.
葛愉成 《中国物理》2006,15(12):2909-2919
In this paper the laser-phase determination methods and transfer equations are presented to directly reconstruct the detailed temporal structures of ultra-short extreme ultraviolet (xuv) pulses from the measured photoelectron energy spectra (PES). Each transfer equation includes one of PID (proportional-integral-differential) terms of PES. The intensity and instantaneous frequency of attosecond xuv can be retrieved from the integral term of PES. The intensity profiles of narrow bandwidth atto- and femtosecond xuvs can be rebuilt from the proportional and differential terms of PES respectively. The methods and equations may be used to improve time resolutions in measuring ultrashort pulses.  相似文献   

15.
Photoelectron spectra (PES) of nitrophenols and nitroanisoles were measured and interpreted with the aid of previously reported PES of nitrobenzene, phenol and anisole. The effect of the intramolecular hydrogen bond is discussed in the case of o-nitrophenol.  相似文献   

16.
We present high-resolution photoelectron spectra on the A15-type conventional superconductor V 3Si, where-for the first time-both singularities of the BCS density of states can be resolved by photoemission spectroscopy (PES). With a transition temperature of about T(c) approximately 17 K the gap Delta(gap) of this compound has a magnitude of approximately 5 meV. A measurement by PES on this small energy scale requires a very high energy resolution (DeltaE less, similar5 meV) and sample temperatures significantly below T(c).  相似文献   

17.
We have obtained photoelectron spectra (PES) for silicon cluster anions with up to 20 atoms. Efficient cooling of species in the source has allowed us to resolve multiple features in the PES for all sizes studied. Spectra for an extensive set of low-energy Si(-)(n) isomers found by a global search have been simulated using density functional theory and pseudopotentials. Except for n = 12, calculations for Si(-)(n) ground states agree with the measurements. This does not hold for other plausible geometries. Hence PES data validate the tricapped trigonal prism morphologies for medium-sized Si clusters.  相似文献   

18.
葛愉成 《中国物理 B》2008,17(12):4492-4497
The photoelectron energy spectra (PESs) excited by monochromatic femtosecond x-ray pulses in the presence of a femtosecond laser are investigated. APES is composed of a set of separate peaks, showing interesting comb-like structures. These structures result from the quantum interferences between photoelectron wave packets generated at different times. The width and the localization of each peak as well as the number of peaks are determined by all the laser and x-ray parameters. Most of peak heights of the PES are higher than the classical predictions.  相似文献   

19.
The X-ray PES spectra of a number of manganese carbonyl complexes are reported. The binding energies are interpreted as functions of the structure and  相似文献   

20.
We have measured and analyzed the photoemission spectra (PES) of a C70 film in the photon energy region from 13.4 eV to 98.4 eV. The photoelectron intensities of two C 2p π-derived features (denoted by A and B) oscillate regularly in the whole energy region with some fine structures below ∼30 eV. To obtain the detailed information of the oscillations, we have developed a sophisticated but practical procedure for intensity calculation. The procedure consists of two core concepts. The first is ascribing the PES features to their corresponding molecular orbitals with the help of density functional calculations. The second is a background subtraction algorithm. With this procedure, we obtained the oscillating behavior for individual features (A and B), which is by and large consistent with the predictions based on the spherical symmetric approximation although C70 has the ellipsoidal shape. Owing to the solid state effect, the oscillating amplitudes of the A/B intensity ratios are smaller than those of gas phase C70, but an orbital shift reported recently was not observed on our sample. The oscillating curve of a deeper feature, which consists of both σ and π states, are also reported.  相似文献   

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