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151.
采用一种新的原位Raman光谱技术对CO2在熔融碳酸盐燃料电池中的NiO阴极的溶解过程中的微观作用进行初步研究。结果表明,CO2气体极易吸附于NiO阴极的表面,在含氧气氛及熔融碳酸盐的条件下,吸附的CO2与活化态O2相互作用形成碳酸根,并进入熔盐电解质,NiO表面的脱附态CO2驰可与NiO中的晶格氧作用,导致NiO的溶解破坏。 相似文献
152.
氧化钛纳米管阵列制备及形成机理 总被引:34,自引:0,他引:34
采用电化学阳极氧化法在HF水溶液体系使纯钛表面形成一层结构规整有序的高密度TiO2纳米管阵列,考察了几种主要的实验参数(阳极氧化电压、温度、时间、电解液浓度)对TiO2纳米管阵列形貌和尺寸的影响.结果表明,阳极氧化电压是影响氧化钛形貌和纳米管尺寸的最主要因素,而温度和电解液浓度只影响TiO2纳米管阵列形成的时间.对TiO2纳米管阵列进行X射线衍射(XRD)和扫描电子显微镜(SEM)的分析,初步表征了TiO2纳米管阵列的电学性质.并讨论了TiO2纳米管的形成机理. 相似文献
153.
TiO2-V2O5纳米复合膜的制备及防腐蚀性能 总被引:5,自引:0,他引:5
采用溶胶-凝胶法和浸渍提拉技术在316L不锈钢表面构筑纳米TiO2薄膜和“夹心”式TiO2-V2O5复合薄膜(TiO2/TiO2-V2O5/TiO2), 应用AFM和XRD表征膜的形貌及纳米颗粒的晶型. 结合光、电化学方法测试了复合膜在0.5 mol•L-1 NaCl溶液(pH=4.6)中暗态或紫外照射条件下的防腐蚀性能. 结果表明, TiO2/TiO2-V2O5/TiO2复合膜具有双重保护功能, 即在紫外光照下可以起到光生阴极保护的作用, 特别是当停止光照后, 光生电位仍可维持在较低的电位长达6 h以上. 同时作为表面阻挡层, 可显著提高金属的耐腐蚀性. 相似文献
154.
Flexible Cu(In,Ga)Se2 Thin-Film Solar Cells on Polyimide Substrate by Low-Temperature Deposition Process
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The electrical and structural properties of polycrystalline Cu(In, Ga)Se2 films grown on polyimide (PI) substrates below 400℃ via one-stage and three-stage co-evaporation process have been investigated by x-ray diffraction spectra (XRD), scanning electron microscopy (SEM) and Hall effect measurement. As shown by XRD spectra, the stoichiometric CIGS films obtained by one-stage process exhibit the characteristic diffraction peaks of the (In0.68Ga0.32)2Se3 and Cu(In0.7Ga0.3)2Se. It is also found that the film structures indicate more columnar and compact than the three-stage process films from SEM images. The stoichiometric CIGS films obtained by three-stage process exhibit the coexistence of the secondary phase of (In0.68Ga0.32)2Se3, Cu2-xSe and Cu(In0.7Ga0.3)2Se. High net carrier concentration and sheet conductivity are also observed for this kind of film, related to the presence of Cu2-xSe phase. As a result, when the CIGS film growth temperature is below 400℃, the three-stage process is inefficient for solar cells. By using the one-stage co-evaporation process, the flexible CIGS solar cell on a PI substrate with the best conversion efficiency of 6.38% is demonstrated (active area 0.16cm^2). 相似文献
155.
The two-dimensional total routhian surface calculations have been carried out to study the triaxial superdeformed structure of a neutron-rich nucleus
173Hf firstly. In particular the effects of the rotational frequency ω and pairing-energy gap parameter Δ
are discussed in detail in the course of shaping its triaxial superdeformation; additionally the neutron-shell correction energy is
analyzed with emphasis in the confirmed triaxial superdeformed nucleus 173Hf. Finally, more systematical results have been investigated for some confirmed superdeformed nuclei experimentally and a few predicted triaxial superdeformed nuclei theoretically with quadropole deformation ε2≈0.4 and triaxial deformation
γ≈20º or
30º in the Z=72 region. 相似文献
156.
A new experimental approach to the study of the two-dimensional compressible flow phenomena is presented. In this technique,
a variety of compressible flows were generated by bursting plane vertical soap films. An aureole and a “shock wave” preceding
the rim of the expanding hole were clearly observed using traditional high-speed flash photography and a fast line-scan charge
coupled device (CCD) camera. The moving shock wave images obtained from the line-scan CCD camera were similar to the x–t diagrams in gas dynamics. The moving shock waves cause thickness jumps and induce supersonic flows. Photographs of the supersonic
flows over a cylinder and a wedge are presented. The results suggest clearly the feasibility of the “soap film shock tube”.
Received: 11 May 2000/Accepted: 2 November 2000 相似文献
157.
GaN layers with different polarities prepared by radio frequency molecular beam epitaxy and characterized by Raman scattering
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GaN layers with different polarities have been prepared by radio-frequency
molecular beam epitaxy (RF-MBE) and characterized by Raman
scattering. Polarity control are realized by controlling
Al/N flux ratio during high temperature AlN buffer growth. The Raman results
illustrate that the N-polarity GaN films have frequency shifts at $A_{1}$(LO)
mode because of their high carrier density; the forbidden $A_{1}$(TO) mode
occurs for mixed-polarity GaN films due to the destroyed translation
symmetry by inversion domain boundaries (IDBS); Raman spectra for
Ga-polarity GaN films show that they have neither frequency shifts mode nor forbidden
mode. These results indicate that Ga-polarity GaN films have a better
quality, and they are in good agreement with the results obtained from the
room temperature Hall mobility. The
best values of Ga-polarity GaN films are 1042 cm$^{2}$/Vs with a carrier
density of 1.0$\times $10$^{17}$~cm$^{ - 3}$. 相似文献
158.
模拟水中白铜B30耐蚀性影响因素的光电化学研究 总被引:4,自引:0,他引:4
用动电位伏安法和光电化学方法对模拟水中白铜B30耐蚀性影响因素进行了研究. 白铜B30表面膜显示p-型光响应, 光响应来自电极表面的Cu2O层, 在模拟水溶液中表面膜的半导体性质会发生转变, 由p-型转为n-型; 在不同 Cl-, SO42-浓度的模拟水溶液中, 电位正向扫描时呈现阳极光电流, 电位负向扫描时随着Cl-, SO42-离子浓度的增加, 光响应由p-型向n-型转变, 阳极光电流峰面积与阴极光电流峰面积之比增大, 耐蚀性能降低; 随着温度的升高, 白铜B30的耐蚀性能降低; 在pH=7~9之间, 其耐蚀性能随着pH的升高而提高, 当pH>9时, 其耐蚀性能随着pH的升高呈降低趋势. 相似文献
159.
DU Rong-Gui HU Rong-Gang FENG Zu-De WANG Zhou-Cheng HU Yan-Ying TAN Jian-Gang LIN Chang-Jian 《高等学校化学学报》2000,21(Z1):423
Reinforcing steel in concrete is usually in a passive condition due to the high alkalinity of the pore solution contained in the pores of concrete. However, the passivation may be lost and the corrosion occurs on the steel by a deceased of pH due to carbonation and/or by the penetration of chloride ions which come from the corrosion environment at the metal concrete interface. Pitting corrosion caused by the chloride is most harmful. Corrosion inhibitors can be applied to protect steel in the presence of chloride ions. The anticorrosion action of NaNO2 on the reinforcing steel in the simulated concrete solution containing NaCl has been studied using electrochemical technique and the other methods in this paper. 相似文献
160.
In practice, low temperature sintering is always the most desirable route to fabricate ceramic composites for industrial manufacturers and an economic way to produce ceramics with unique microstructure for technological applications. Normally the sintering temperature for dense YSZ coating is about 1500℃. Recently many studies have experimentally found that dense ceramic composites can be achieved at a sintering temperature lower by several hundred degrees Celsius for nano-sized powders than for coarse powders[1-2]. Electrochemical processing is an attractive method for making ceramic films and powders because it offers the advantages of low temperature sintering, low cost and good control of the green forms[3-4]. 相似文献