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Liu F.G.,Tianjin University | Liu F.G.,China offshore Oil Engineering Co. | Liu F.G.,China National Offshore Oil Corporation | Wu S.R.,Minerals and Metallic Materials Inspection Center | Lu C.S.,China National Offshore Oil Corporation
Corrosion Engineering Science and Technology | Year: 2011

Calcareous deposits were formed on steel under cathodic protection conditions in artificial sea water at various potentials from -0.900 to -1.400 V(SCE). The deposition calcareous layers were characterised by electrochemical impedance spectroscopies, scanning electron microscopy observations and X-ray diffraction analyses. At 20°C, the deposits were composed of calcite CaCO3 when formed at various potentials in solution 1, of brucite Mg(OH)2 and aragonite CaCO3 when formed at potentials from -0.900 to -1.200 V(SCE) and only of brucite when formed at potentials E≤1.300 V(SCE) in solution 2. Magnesium seems to influence the corrosion behaviour of freely corroding steel by causing calcium carbonate to precipitate as aragonite. Aragonite is more effective in covering the surface than calcite and is therefore more functional in preventing oxygen from reaching the steel surface, thereby lowering the corrosion rate. © 2011 Institute of Materials, Minerals and Mining.


Wang Z.-K.,Minerals and Metallic Materials Inspection Center | Li Y.,Minerals and Metallic Materials Inspection Center | Yao C.-G.,Minerals and Metallic Materials Inspection Center | Wang H.,Minerals and Metallic Materials Inspection Center | And 3 more authors.
Yejin Fenxi/Metallurgical Analysis | Year: 2010

The high carbon-chrome iron sample was treated by microwave digestion with hydrofluoric acid and perchloric acid as solvent. The content of silicon and phosphorus was then determined by inductively coupled plasma atomic emission spectrometry. The working conditions of inductively coupled plasma atomic emission spectrometer were optimized. In this study, 251.612 nm and 213.618 nm were used as the analytical lines of silicon and phosphorus, respectively. The interference and correction of matrix iron, chrome and acids were discussed. The results indicated that iron and chrome had little interference with the determination, which could be eliminated by matrix matching method. The interference of acid could be reduced or eliminated by adding the same amount of acid into sample and standard sample. The detection limits of silicon and phosphorus were 0. 0015% and 0.0021%, respectively. The standard sample and actual sample of high carbon-chrome iron were analyzed by this method. The results were consistent with the certified values or those obtained by other methods(alkali fusion ICP-AES method, XRF method). The relative standard deviations(RSD) were in the range of 0.40%-5.3%(n=11).


Qian Y.-Y.,Chinese PLA General Hospital | Xue L.,CAS Beijing National Laboratory for Molecular | Hu D.-X.,Minerals and Metallic Materials Inspection Center | Li G.-P.,CAS Beijing National Laboratory for Molecular | Jiang H.,CAS Beijing National Laboratory for Molecular
Dyes and Pigments | Year: 2012

A novel quinoline-based fluorescent probe for detecting H 2O 2 is described. In aqueous solution, the probe exhibits fluorescence emission at 542 nm originating from the monocationic species. The reaction between the probe and H 2O 2 causes quenching of the emission at 542 nm and simultaneously yields a significant hypsochromic shift of the emission maximum to 480 nm due to the H 2O 2-triggered boronate cleavage process. Thus, a single-excitation, dual-emission ratiometric measurement with a large blue shift in emission (Δλ = 62 nm) and remarkable changes in the ratio (F 480 nm/F 542 nm) of the emission intensity (R/R 0 up to 8.3-fold) can be established. Moreover, the probe can also afford high selectivity for detecting H 2O 2 over other biological reactive oxygen species. © 2012 Elsevier Ltd. All rights reserved.


Hu D.-X.,Minerals and Metallic Materials Inspection Center | Zhao J.-Y.,Minerals and Metallic Materials Inspection Center | Jin B.-Y.,Minerals and Metallic Materials Inspection Center | Fu Z.-Q.,Minerals and Metallic Materials Inspection Center
Yejin Fenxi/Metallurgical Analysis | Year: 2014

Representativeness and accuracy of inclusion analysis should be figured out for the determination and characterization of non-metallic inclusions in low alloy steel. The non-metallic inclusions components in low alloy steel, as well as the single spark pulse distribution and spectra was studied. In combination with quantitative metallography, SEM and EDS, the main existence state of the inclusions in low alloy steel and the relevance between abnormal spectral signals and the particle number and size of the inclusions were explored. It was found that the particle number of larger inclusions had a greater significant impact on the relative frequency of the abnormal sparks, and the ratio of abnormal average intensity to the overall average intensity was also closely related with the average particle size of the inclusion. When the contents of the main elements in low alloy steel were measured, the system could identify and detect non-metallic inclusions with single spark pulse distribution and spectra at the same time and thus realized the qualitative and quantitative determination of non-metallic inclusions with the combination of physical means, namely, metallography and SEM, so it is suitable for the daily quality control of low alloy steels.


Wu S.-R.,Minerals and Metallic Materials Inspection Center | Wang H.,Minerals and Metallic Materials Inspection Center | Li Q.-B.,Minerals and Metallic Materials Inspection Center | Ma D.-Q.,Minerals and Metallic Materials Inspection Center | And 2 more authors.
Yejin Fenxi/Metallurgical Analysis | Year: 2014

Acid-solution was used to digest the copper matte sample, and then hydride generation-atomic fluorescence spectrometry was employed to determine the arsenic content in the sample. The sample digestion method, various factors that influence the spectral measurement, and the interference from coexisting elements were discussed. The results showed that when the mixed acid of hydrochloric acid-nitric acid-sulfuric acid was used to dissolve sample, thiourea-ascorbic acid was used as masking agent and prereduction agent, the coexisting elements did not significantly interfere the determination. The concentration of arsenic in the range of 0-100 μg/L exhibited good linearity, and the detection limit of the method was 0.05 μg/L. The method was applied to the analysis of actual samples, and the measured results were consistent with those obtained by inductively coupled plasma atomic emission spectrometry, with the relative standard deviation (n=11, RSD) being less than 7%, and the recovery being 90%-95%.


Wang Z.-H.,University of Science and Technology Beijing | Yang B.,University of Science and Technology Beijing | Yang B.,CAS International Center for Materials Physics | Gu C.-D.,Zhejiang University | And 3 more authors.
Gongneng Cailiao yu Qijian Xuebao/Journal of Functional Materials and Devices | Year: 2011

Taking a slice of Fe as an anode, the relationship of pulse electrode position parameters with the microstructure and magnetic property of Fe-Co alloy film deposited on pure Cu substrate by high-frequency (20-140 kHz) pulse currents was studied. Influence of solubility of Fe on composition and property of Fe-Co alloy deposits was also investigated. EPMA images showed that the surface roughness of Fe-Co films increases with duty cycle increasing. SEM micrographs revealed that with the increase of pulse frequency used in this experiment, the deposition rates are enhanced, which so increases the thick- ness of the Fe-Co films. Hence, high-frequency pulse electrode position technique was used for a new type of high-rate plating technique. XRD patterns showed that the intensity ratio between the fcc(111) and the bcc (110) at first decreases slightly and then increases abruptly as the pulse frequency increases. VSM results revealed that coercivity of Fe-Co film deposited at 140 kHz is lower compared with those deposited at 20 or 80 kHz, which indicates that the film with good soft magnetic property was electrode-posited at high frequency. Fe 65Co 35 film with saturation magnetizations of 2.12 T was prepared, but its coercivity was high. The performance of the Fe, Co and Ti anode was compared through coercivity value of deposits, and it was observed that the Co anode is superior to the others.


Hu D.-X.,Minerals and Metallic Materials Inspection Center | Ma D.-Q.,Minerals and Metallic Materials Inspection Center | Pan H.-W.,Minerals and Metallic Materials Inspection Center | Wang Z.-K.,Minerals and Metallic Materials Inspection Center | And 3 more authors.
Yejin Fenxi/Metallurgical Analysis | Year: 2011

The conditions of high-pressure microwave digestion in closed vessels are discussed in detail and optimized. Most of chrome ores from main business countries were tested by this method. The results showed that chrome ores could be digested completely under such conditions as: 0.20 g of sample weight, 7 mL of H2SO4, 5 mL of H3PO4, 1 mL of HBF4, high-pressure digestion power at 1200 W and digestion time of 40 min. Using this digestion conditions, two national primary reference ores of chromium containing different content of chromium sesquioxide were determined for 10 times by potentiometric titration. The average value of the determination results were consistent with the certified values with a relative error of 0.018%-0.024% and relative standard deviation of 0.11%-0.14%. The proposed method has also been applied to the digestion and determination of chromium ores from different countries. The results of chromium sesquioxide were all within the allowable error.


Wei H.,Minerals and Metallic Materials Inspection Center | Sun H.,Nankai University | Wang S.,Minerals and Metallic Materials Inspection Center | Chen G.,Minerals and Metallic Materials Inspection Center | And 3 more authors.
Journal of Natural Gas Chemistry | Year: 2010

Nanostructured tin dioxide (SnO2) powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method. The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders. Sensing behavior of the sensor was investigated with various gases including CO, H2, NH3, hexane, acetone, ethanol, methanol and H2S in air. The as-synthesized gas sensor had much better response to H2S than to other gases. At the same time, the CuO/SnO2 sensor had enough sensitivity, together with fast response and recovery, to distinguish H2S from those gases at 160 and 210 °C. Therefore, it might have promising applications in the future. Copyright © 2010, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. All rights reserved.


Wang Z.-K.,Minerals and Metallic Materials Inspection Center | Chen Y.,Minerals and Metallic Materials Inspection Center | Li Y.,Minerals and Metallic Materials Inspection Center | Wang J.,Minerals and Metallic Materials Inspection Center | And 5 more authors.
Yejin Fenxi/Metallurgical Analysis | Year: 2010

With samples decomposed by nitric acid, hydrofluoric acid and mixed acid of sulfuric acid-phosphoric acid, Mn in ferrophosphorus was determined by periodate spectrophotometry. The acid system for sample dissolution was established, and the optimal measuring wavelength of 525 nm was selected. The influence of acidity and coexisting elements were discussed. The results showed that matrix elements of Fe and P had little influence on the determination. The interference could be neglected when the addition amount of sulfuric acid (1 + 1) and phosphoric acid (1 + 1) was within 20 mL. The detection limit for Mn was 0.003%. The proposed method has been applied to the determination of ferrophosphorus certified reference materials and actual samples. The analytical results were consistent with the certified values and those obtained by alkali deliquescence-acidification spectrophotometry, and relative standard deviation (RSD) was between 0.34% and 2.2%.

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