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81.
Comparative study of bis-piperidiniummethyl-urea and mono-piperidiniummethyl-urea as volatile corrosion inhibitors for mild steel 总被引:1,自引:0,他引:1
Bis-piperidiniummethyl-urea (BPMU) and mono-piperidiniummethyl-urea (MPMU) were developed as novel volatile corrosion inhibitors (VCIs). Their vapor corrosion inhibition property was evaluated by volatile inhibiting sieve test (VIS) and vapor inhibiting ability test (VIA). Volatile weight-loss test in a closed space was used to compare their volatility. Electrochemical impedance spectroscopy of a volatile corrosion inhibitor monitor (VCIM) was applied to study the effect of BPMU and MPMU on the corrosion inhibition of mild steel in thin electrolyte layer. The results show that BPMU has the better protection effect compared with MPMU. Adsorption of BPMU and MPMU on steel surface was investigated by X-ray photoelectron spectroscopy (XPS). It was shown that one BPMU molecule has two N atoms to coordinate with one Fe atom, and that one MPMU molecule has one N atom to coordinate with one Fe atom. The quantum chemical parameters were obtained by PM3 semi-empirical method. BPMU has the smaller HOMO-LUMO energy gap and the smaller net positive charge intensities of 4N and 8N atoms in its molecule. 相似文献
82.
During bio-oxidation of sulfides, the chemical state change of sulfur is a complex and key factor. It is not only an indicator of the extent and intensity of the bio-oxidation, but also controls the property of bio-leaching medium and the period of oxidation. The chemical state of sulfur in sulfides oxidized by leaching bacteria was studied with XPS. Sulfide minerals in the arsenic-bearing gold concentrate consist of pyrite, arsenopyrite, chalcopyrite, galena, sphalerite and so on. In order to probe the pattern of the chemical state change of sulfur in the bio-oxidation residue of arsenic-bearing gold concentrate, the structure of the grains, and the surface nature of the residue, XPS test was carried out through different sputtering duration. The study of XPS clearly shows that: sulfides is progressively oxidized from the surface of minerals to the core by leaching bacteria; the chemical valence of sulfur changes from S^2- or [S2]^2- to [SO4]^2- ; sulfur in the core is in a reduction state, S^2- or [S2]^2- , but exists in an oxidation state S^6 on the surface; due to the chemical state change of sulfur, mineral phase of the bio-oxidation residue is also changed(sulfides inside, while sulfates outside); the layered structure is found in the grains of the bio-oxidation residue. 相似文献
83.
NH_3 Plasma Surface Treatments of Engineering Fluoropolymers: A Way to Enhance Adhesion of Ni or Cu Thin Films Deposited by Electroless Plating 总被引:4,自引:0,他引:4
FLUOROPOLYMERS(FPs)are thermoplasticmaterials which exhibit a number of unique chemicaland physical characteristics that no other man-madeplastic product gets together.For example,FPs showvery good resistance to almost all chemicals,excellentwater vapor barrier properties,high thermal stability,outstanding electrical insulation properties(lowdielectric constant and dissipation factors),extremelylow frictional coefficient giving them high auto-lubrication properties,high resistance to rad… 相似文献
84.
85.
XPS(XML Paper Specification)是微软推出的一种固定布局的电子文档格式,能达到所见即所得的打印效果。本文详细分析了XPS文档的结构、组织形式,并对其中的字形部分以解析和实现的形式进行了详细的剖析。 相似文献
86.
Yusuke Fukui Yosuke Honda Yasuhiro Yamauchi Michiko Okafuji Masahiro Sakai Mikihiko Nishitani Yusuke Takata 《Journal of the Society for Information Display》2010,18(12):1090-1094
Abstract— MgO thin film is currently used as a surface protective layer for dielectric materials because MgO has a high resistance during ion sputtering and exhibits effective secondary electron emission. The secondary‐electron‐emission coefficient γ of MgO is high for Ne ions; however, it is low for Xe ions. The Xe content of the discharge gas of PDPs needs to be raised in order to increase the luminous efficiency. Thus, the development of high‐γ materials replacing MgO is required. The discharge properties and chemical surface stability of SrO containing Zr (SrZrO) as the candidate high‐γ protective layer for noble PDPs have been characterized. SrZrO films have superior chemical stability, especially the resistance to carbonation because of the existence of a few adsorption sites due to their amorphous structure. The firing voltage is 60 V lower than that of MgO films for a discharge gas of Ne/Xe = 85/15 at 60 kPa. 相似文献
87.
Vishal BalouriaAuthor Vitae Arvind KumarAuthor VitaeA. SinghAuthor Vitae S. SamantaAuthor VitaeA.K. DebnathAuthor Vitae Aman MahajanAuthor VitaeR.K. BediAuthor Vitae D.K. AswalAuthor Vitae S.K. GuptaAuthor VitaeJ.V. YakhmiAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(2):466-472
The conductometric gas sensing characteristics of Cr2O3 thin films - prepared by electron-beam deposition of Cr films on quartz substrate followed by oxygen annealing - have been investigated for a host of gases (CH4, CO, NO2, Cl2, NH3 and H2S) as a function of operating temperature (between 30 and 300 °C) and gas concentration (1-30 ppm). We demonstrate that these films are highly selective to H2S at an operating temperature of 100 °C, while at 220 °C the films become selective to Cl2. This result has been explained on the basis of depletion of chemisorbed oxygen from the surface of films due to temperature and/or interaction with Cl2/H2S, which is supported experimentally by carrying out the work function measurements using Kelvin probe method. The temperature dependent selectivity of Cr2O3 thin films provides a flexibility to use same film for the sensing of Cl2 as well as H2S. 相似文献
88.
Theoretical models and ab initio Hartree-Fock wavefunctions have been used to investigate the S(2p) core level binding energies (BE), of pyrolized S-containing, carbonaceous materials. Comparison between experimental and calculated data for thiophene permits the accuracy of the present approach to be established. A systematic study of different situations demonstrates that, in these materials, non-oxidized S atoms can show peaks at very high BE relative to the C(1s) peak at 285.0 eV. This study confirms that the peak at 164.1 eV corresponds to ‘thiophenic’ S atoms. On the other hand, it shows that the peaks at higher BE could correspond to S atoms replacing C atoms in three-coordinated structures of graphene layers, in agreement with the arguments suggested in the experimental works. The energetic similarity between the two peaks at very high BE makes it difficult to differentiate between them, although the results of the present study seem to suggest that the peak at experimental BE ≈ 166 eV could correspond to S atoms coordinated to two C and one H atoms at the edge of graphene layers, while the peak at ≈ 169 eV would correspond to S atoms replacing C atoms in inner positions of the graphene layers, and it is bonded to three C atoms. 相似文献
89.
葛涛 《淮南工业学院学报》2013,(4):12-14,54
研究煤中硫的结构、赋存形态对有效脱除煤中硫的影响,节约回收稀缺炼焦煤资源,为建立煤中硫的高效脱除方法提供科学依据,提高煤炭综合利用水平,节约稀缺煤种资源具有重要意义。利用XPS测试方法对汾西高硫炼焦煤中硫的赋存形态进行研究,结果表明,煤中无机硫含量较低,以有机硫为主。有机硫的赋存状态共有3类,含量从高到低依次为硫醇(醚)类、亚砜类、噻吩类。 相似文献
90.
Ceria supported 2 wt% Pd catalysts for low-temperature methane combustion were prepared by the impregnation (IM) and deposition–precipitation (DP) methods, which are denoted as Pd–IM and Pd–DP, respectively. DP was found to be an available method for achieving high activity and stability of the Pd/CeO2 catalyst. The temperatures for methane ignition (T10%) and total conversion (T100%) over Pd–DP are 224 and 300 °C at GHSV of 50,000 h−1, which are 83 and 110 °C lower than the corresponding temperatures of Pd/Al2O3. X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS) analyses show that palladium species in Pd–DP is highly dispersed, positively charged and difficultly reduced. Raman spectra disclosed that the largest concentration of defects and/or oxygen vacancies was formed in Pd–DP catalyst. A kind of cationic PdOδ+ sites with higher binding energies than PdO are in close vicinity to the oxygen vacancies in the CeO2 support and might act as the active centers for methane oxidation. Furthermore, the deactivation and steam aging tests for Pd–DP showed that the performance of this type of palladium was very stable and could be repeatedly recovered after several long time aging tests. 相似文献