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差分光学吸收光谱(DOAS)技术在烟气SO2监测中的应用 总被引:19,自引:0,他引:19
本文将差分光学吸收光谱(Differential Optical Absorption Spectroscopy,DOAS)技术中的浓度反演方法运用到烟气SO2监测中.利用SO2分子在300nm附近具有强吸收的特性,测量出烟气SO2的吸收光谱,用DOAS方法反演出SO2分子的浓度,消除了烟气中烟尘、水汽和其它成分的影响,使在线实时测量成为可能,在实验室内对几种SO2分子浓度样气进行了测量和浓度反演. 相似文献
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色散SiO2/TiO2薄膜组成的Fibonacci序列一维光子晶体在可见光波段的传输特性 总被引:1,自引:0,他引:1
用特征矩阵法研究了由正常色散SiO2/TiO2薄膜组成的Fibonacci序列一维光子晶体在可见光波段的传输特性,并与无色散时的传输特性做了对比。结果表明,随序列项数的增加,相应的前一序列的透射谱中透射率较低的凹带逐渐变成禁带,禁带数增加;初始介质是低折射率的SiO2薄膜时比高折射率的TiO2薄膜时各序列的透射谱中的禁带数多,各禁带的宽度和中心波长基本相同;在总厚度一定的条件下,随SiO2薄膜的厚度增大(TiO2薄膜的厚度减小),禁带的宽度减小,禁带的中心波长基本不变;随入射角增大,禁带的中心波长向短波方向移动,禁带宽度变小。在其它相同条件下,无色散时的最宽禁带和最宽禁带的中心波长比有色散时的最宽禁带和最宽禁带的中心波长都有增加。 相似文献
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本文利用X射线粉末衍射和位敏探测技术,研究了R2Fe4/3W2/3O7(R=Er、Yb、Dy)化合物经高温高压处理后的变化情况。在3.7 GPa,1 200 ℃条件下,六方相R2Fe4/3W2/3O7化合物按两种方式分解,而直接由R2O3,Fe2O3和WO3原料出发,经上述同样的高温高压条件合成所得的产物与六方相高温高压分解产物相同,均为R2WO6、RFeO3、WO3和Fe2O3的多相聚合物。同时给出了R2Fe4/3W2/3O7六方相高温高压下的稳定区范围。 相似文献
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玻璃化转变温度(Tg)是聚合物重要的特性参数,压缩CO2环境中聚合物的玻璃化转变温度的测定,更是超临界流体技术在聚合物科学领域中成功应用的前提条件。根据蠕变柔量实验原理,自建一套测定高压环境下玻璃化转变温度的实验装置。利用该装置对聚对苯二甲酸乙二醇酯(PET)、聚苯乙烯(PS)、聚氯乙烯(PVC)以及聚甲基丙烯酸甲酯(PMMA)在大气中及压缩CO2环境中的Tg进行了测定。设定实验的平衡吸附温度为室温,平衡吸附压力范围分别为:PET,0~3.5 MPa;PS,0~11.0 MPa;PVC,0~9.0 MPa;PMMA,0~4.5 MPa。在大气中测定的结果与文献中的结果相吻合,表明所设计的实验方法及实验装置是可靠并有效的,可用于高压环境下聚合物的玻璃化转变温度的测定。从压缩CO2中的聚合物Tg测定结果可以看出,CO2对聚合物具有较明显的溶胀、增塑作用,可显著降低聚合物的Tg。 相似文献
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利用溶胶-凝胶法制备出了纳米晶ZnO与含有3%摩尔分数SnO2的ZnO/SnO2复合材料,在六面顶压机上对制备出的两种样品进行了室温下、6GPa的高压处理。采用X射线衍射(XRD)、透射电子显微镜(TEM)和光致荧光谱(PL)等方法,对高压处理前后样品的结构和发光性质进行了表征。结果表明:高压处理后回收到的纳米晶ZnO和ZnO/SnO2复合材料的平均粒径分别减小5.9%和26.3%;高压处理后ZnO和ZnO/SnO2复合材料光致发光谱的发光带强度都有所降低,但ZnO/SnO2复合材料发光带强度降低幅度比纯ZnO小,对产生这些现象的原因进行了讨论。 相似文献
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Two-layer ZrO2/SiO2 and SiO2/ZrO2 films were deposited on K9 glass substrates by sol–gel dip coating method. X-ray photoelectron spectroscopy (XPS) technique was used to investigate the diffusion of ZrO2/SiO2 and SiO2/ZrO2 films. To explain the difference of diffusion between ZrO2/SiO2 and SiO2/ZrO2 films, porous ratio and surface morphology of monolayer SiO2 and ZrO2 films were analyzed by using ellipsometry and atomic force microscopy (AFM). We found that for the ZrO2/SiO2 films there was a diffusion layer with a certain thickness and the atomic concentrations of Si and Zr changed rapidly; for the SiO2/ZrO2 films, the atomic concentrations of Si and Zr changed relatively slowly, and the ZrO2 layer had diffused through the entire SiO2 layer. The difference of diffusion between ZrO2/SiO2 and SiO2/ZrO2 films was influenced by the microstructure of SiO2 and ZrO2. 相似文献
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Aniruddha Kumar J.P. NilayaD.J. Biswas R.B. BhattMohd. Afzal J.P. PanakkalH.S. Kamath 《Applied Surface Science》2011,257(16):7263-7267
Pulsed laser assisted removal of uranium dioxide and thorium dioxide particulates from stainless steel surface have been studied using a TEA CO2 laser. Decontamination efficiency is measured as a function of laser fluence and number of pulses. Threshold fluence for the removal of UO2 particulates has been found to be lower than that required for the removal ThO2 particulates. Usage of a ZnSe substrate, that is transparent to the laser wavelength used here, enabled us to decouple the cleaning effect arising out of absorption in the particulates from that in the substrate and has contributed towards understanding the mechanism responsible for cleaning. The experimental observations are also corroborated by simple theoretical calculations. 相似文献
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O. Bethge C. Henkel S. AbermannG. Pozzovivo M. Stoeger-PollachW.S.M. Werner J. SmolinerE. Bertagnolli 《Applied Surface Science》2012,258(8):3444-3449
La2O3 grown by atomic layer deposition (ALD) and thermally grown GeO2 are used to establish effective electrical surface passivations on n-type (1 0 0)-Ge substrates for high-k ZrO2 dielectrics, grown by ALD at 250 °C substrate temperature. The electrical characterization of MOS capacitors indicates an impact of the Ge-surface passivation on the interfacial trap density and the frequency dependent capacitance in the inversion regime. Lower interface trap densities can be obtained for GeO2 based passivation even though a chemical decomposition of the oxidation states occur during the ALD of ZrO2. As a consequence the formation of a ZrGeOx compound inside the ZrO2 matrix and a decline of the interfacial GeO2 are observed. The La2O3 passivation provides a stable amorphous lanthanum germanate phase at the Ge interface but also traces of Zr germanate are indicated by X-ray-Photoelectron-Spectroscopy and Transmission-Electron-Microscopy. 相似文献
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Pascal Ifeacho Hartmut Wiggers Paul Roth 《Proceedings of the Combustion Institute》2005,30(2):2577-2584
SnO2/TiO2 mixed oxides with primary particle size ranging between 5 nm dp 12 nm were synthesized by doping a H2/O2/Ar flame with Sn(CH3)4 and Ti(OC3H7)4 co-currently. The effects of “flow coordinate,” concentration and flame configurations were investigated with respect to particle size and morphology of the generated mixed oxides. In situ characterization of the mixed oxides was performed using the particle mass spectrometer (PMS), while XRD, TEM, BET and UV–Vis were performed ex situ. Results obtained showed that primary particle size of mixed oxides can be controlled by varying experimental parameters. The mixed oxides have interesting properties compared to those of the pure oxides of TiO2 and SnO2, which were also synthesized in flames earlier. Band gap tuning opportunities are possible using mixed oxides. 相似文献
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Yusuke Arai 《Journal of luminescence》2011,131(12):2652-2660
Alkaline hexafluorostantanate red phosphors Na2SnF6:Mn4+ and Cs2SnF6:Mn4+ are synthesized by chemical reaction in HF/NaMnO4 (CsMnO4)/H2O2/H2O mixed solutions immersed with tin metal. X-ray diffraction patterns suggest that the synthesized phosphors have a tetragonal symmetry with the space group D4h14 (Na2SnF6:Mn4+) and a trigonal symmetry with the space group D3d3 (Cs2SnF6:Mn4+). Photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, and the Raman scattering techniques are used to investigate the optical properties of the phosphors. The Franck-Condon analysis of the PLE data yields the Mn4+-related optical transitions to occur at ∼2.39 and ∼2.38 eV (4A2g→4T2g) and at ∼2.83 and ∼2.76 eV (4A2g→4T1g) for Na2SnF6:Mn4+ and Cs2SnF6:Mn4+, respectively. The crystal field parameters (Dq) of the Mn4+ ions in the Na2SnF6 and Cs2SnF6 hosts are determined to be ∼1930 and ∼1920 cm−1, respectively. Temperature-dependent PL measurements are performed from 20 to 440 K in steps of 10 K, and the obtained results are interpreted by taking into account the Bose-Einstein occupation factor. Comprehensive discussion is given on the phosphorescent properties of a family of Mn4+-activated alkaline hexafluoride salts. 相似文献
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We describe the structural properties and electrical characteristics of thin thulium oxide (Tm2O3) and thulium titanium oxide (Tm2Ti2O7) as gate dielectrics deposited on silicon substrates through reactive sputtering. The structural and morphological features of these films were explored by X-ray diffraction, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and atomic force microscopy, measurements. It is found that the Tm2Ti2O7 film annealed at 800 °C exhibited a thinner capacitance equivalent thickness of 19.8 Å, a lower interface trap density of 8.37 × 1011 eV−1 cm−2, and a smaller hysteresis voltage of ∼4 mV than the other conditions. We attribute this behavior to the Ti incorporated into the Tm2O3 film improving the interfacial layer and the surface roughness. This film also shows negligible degrees of charge trapping at high electric field stress. 相似文献
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Double-ceramic-layer (DCL) thermal barrier coatings (TBCs) of La2(Zr0.7Ce0.3)2O7 (LZ7C3) and La2Ce2O7 (LC) were deposited by electron beam-physical vapor deposition (EB-PVD). The composition, interdiffusion, surface and cross-sectional morphologies, cyclic oxidation behavior of DCL coating were studied. Energy dispersive spectroscopy and X-ray diffraction analyses indicate that both LZ7C3 and LC coatings are effectively fabricated by a single LZ7C3 ingot with properly controlling the deposition energy. The chemical compatibility of LC coating and thermally grown oxide (TGO) layer is unstable. LaAlO3 is formed due to the chemical reaction between LC and Al2O3 which is the main composition of TGO layer. Additionally, the thermal cycling behavior of DCL coating is influenced by the interdiffusion of Zr and Ce between LZ7C3 and LC coatings. The failure of DCL coating is a result of the sintering of LZ7C3 coating surface, the chemical incompatibility of LC coating and TGO layer and the abnormal oxidation of bond coat. Since no single material that has been studied so far satisfies all the requirements for high temperature applications, DCL coating is an important development direction of TBCs. 相似文献
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The diamond abrasive particles were coated with the TiO2/Al2O3 film by the sol-gel technique. Compared with the uncoated diamonds, the TiO2/Al2O3 film was excellent material for the protection of the diamonds. The results showed that the incipient oxidation temperature of the TiO2/Al2O3 film coated diamonds in air atmosphere was 775 °C, which was higher 175 °C than that of the uncoated diamonds. And the coated diamonds also had better the diamond's single particle compressive strength and the impact toughness than that of uncoated diamonds after sintering at 750 °C. For the vitrified bond grinding wheels, replacing the uncoated diamonds with the TiO2/Al2O3 film coated diamonds, the volume expansion of the grinding wheels decreased from 6.2% to 3.4%, the porosity decreased from 35.7% to 25.7%, the hardness increased from 61.2HRC to 66.5HRC and the grinding ratio of the vitrified bond grinding wheels to carbide alloy (YG8) increased from 11.5 to 19.1. 相似文献
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T. SrikumarM.G. Brik Ch. Srinivasa RaoN. Venkatramaiah Y. GandhiN. Veeraiah 《Physica B: Condensed Matter》2011,406(19):3592-3598
Li2O-ZrO2-SiO2: Ho3+ glasses mixed with three interesting d-block elemental oxides, viz., Nb2O5, Ta2O5 and La2O3, were prepared. Optical absorption and photoluminescence spectra of these glasses have been recorded at room temperature. The luminescence spectra of Nb2O5 and Ta2O5 mixed Li2O-ZrO2-SiO2 glasses (free of Ho3+ ions) have also exhibited broad emission band in the blue region. This band is attributed to radiative recombination of self-trapped excitons (STEs) localized on substitutionally positioned octahedral Ta5+ and Nb5+ ions in the glass network. The Judd-Ofelt theory was successfully applied to characterize Ho3+ spectra of all the three glasses. From this theory various radiative properties, like transition probability A, branching ratio βr and the radiative lifetime τr, for 5S2 emission levels in the spectra of these glasses have been evaluated. The radiative lifetime for 5S2 level of Ho3+ ions has also been measured and quantum efficiencies were estimated. Among the three glasses studied the La2O3 mixed glass exhibited the highest quantum efficiency. The reasons for such higher value have been discussed based on the relationship between the structural modifications taking place around the Ho3+ ions. 相似文献
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Mechanism of amorphous Ge2Sb2Te5 removal during chemical mechanical planarization in acidic H2O2 slurry 下载免费PDF全文
In this paper, chemical mechanical planarization (CMP) of amorphous Ge2Sb2Te5 (a-GST) in acidic H2O2 slurry is investigated. It was found that the removal rate of a-GST is strongly dependent on H2O2 concentration and gradually increases with the increase in H2O2 concentration, but the static etch rate first increases and then slowly decreases with the increase in H2O2 concentration. To understand the chemical reaction behavior of H2O2 on the a-GST surface, the potentiodynamic polarization curve, surface morphology and cross-section of a-GST immersed in acidic slurry are measured and the results reveal that a-GST exhibits a from active to passive behavior for from low to high concentration of H2O2 . Finally, a possible removal mechanism of a-GST in different concentrations of H2O2 in the acidic slurry is described. 相似文献