Showing papers by "Beijing Institute of Petrochemical Technology published in 2007"

Corrosion resistance property of the ceramic coating obtained through microarc oxidation on the AZ31 magnesium alloy surfaces

Abstract: Microarc oxidation is a recently developed surface treatment technology under anodic oxidation. The magnesium alloy offers various possibilities of application in industry, but its poor property in corrosion resistance, wear resistance, hardness and so on, limited its application. Through microarc oxidation, ceramic coating is directly formed on the surface of magnesium alloy, by which its surface property is greatly improved. In this paper, a dense ceramic oxide coating approximately 20 μm thick was prepared on a AZ31 magnesium alloy through microarc oxidation in a Na 2 SiO 3 –Na 2 WO 4 –KOH–Na 2 EDTA electrolytic solution. The property of corrosion resistance of ceramic coating was studied by CS300P electrochemistry–corrosion workstation, and the main impact factor of the corrosion resistance was also analyzed. Microstructure and phase composition were analyzed by SEM and XRD. The microhardness of the coating was also measured. The basic mechanism of microarc coating formation is explained. The results show that the corrosion resistance property of microarc oxidation coating on the AZ31 magnesium surface is superior to the original samples in the 3.5 wt% NaCl solutions. The microarc oxidation coating is relatively dense and uniform, mainly composed of MgO, MgAl 2 O 4 and MgSiO 3 . The microhardness of the AZ31 magnesium alloy surface attained 410 HV , which was much larger than that of the original AZ31 magnesium alloy without microarc oxidation.

Activity Coefficients at Infinite Dilution of Alkanes, Alkenes, and Alkyl Benzenes in 1-Butyl-3-methylimidazolium Tetrafluoroborate Using Gas−Liquid Chromatography

Abstract: The activity coefficients at infinite dilution, γi∞, for 16 organic solutes, alkanes, alkenes, and alkyl benzenes in the ionic liquid 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]), have been measured by the gas–liquid chromatographic method. The measurements were carried out in the temperature range of (313.15 to 363.15) K. The partial molar excess enthalpies at infinite dilution, HiE,∞, of the solutes in [BMIM][DBP] were also derived from the temperature dependence of the γi∞ values.

Kinetics Analysis on the Ozonation of MIB and Geosmin

Abstract: The ozonation of 2-methylisoborneol (MIB) and geosmin was investigated in both pure and raw water. In a semi-batch reactor, a series of experiments was performed to determine the effect of pH on the ozonation of MIB and geosmin. The results show that pH has a significant effect on the ozonation of both compounds, which supports the theory that OH radical plays an important role on the destruction of MIB and geosmin. Compared with MIB, geosmin is more readily destroyed by ozonation. The ozonation kinetics follow approximately a first-order equation with respect to MIB and geosmin at the pH of 5, 7 and 9, and their rate orders of CO3 at pH 7 are 0.44 and 0.61, respectively. Ozonation of organic matters in the water decreases the ozone concentration leading to a lower removal of MIB and geosmin; at the same time, the formation of OH radical initiated by the organic matters accelerates the ozonation of MIB and geosmin. The ozonation of MIB and geosmin spiked in raw water, settled water and pure water shows th...

The Advantages of Metal Complexes as Catalysts toward Polyolefins ‐ The Vinyl Polymerization of Norbornene

Abstract: Various nickel complexes bearing [N,0], [P,N] ligands as well as the supported nickel complexes were prepared and showed moderate to high catalytic activities for vinyl polymerization of norbornene. The formed polynorbornenes (PNBs) are soluble for measuring both the molecular weights and the molecular weight distributions. Comparing the results in homogeneous catalysis, the PNBs produced by supported catalysts possessed higher molecular weights and slightly broader molecular weight distributions. The reactor fouling generally happens in homogeneous catalytic systems, while spherical polymer particle morphology could be obtained without reactor fouling by using MgCl 2 -supported nickel catalysts.

The effect of vibration on bed voidage behaviors in fluidized beds with large particles

Abstract: The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s-1), amplitude (0 mm-1 mm), bed height (0.1 m-0.4 m) as well as four kinds of particles (belonging to Geldart's B and D groups). The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within ±15%, was proposed.

Research on the properties of inside surface of subsurface pump barrel by N–C–O multi-elements penetrating

Abstract: Subsurface pump usually requires good properties of anti-wear and corrosion resistant because it works in a very bad environment. The performance of the oil-well pump can be distinguishingly improved by intensifying the surface of pump barrel. This paper study the properties of the inside surface of subsurface pump barrel by N–C–O multi-elements penetrating. The modified layer, which is composed of bright layer and transition layer, obtained a thickness of 70 μm at 670 °C, 3 h. The microhardness of the modified layer attains 700 HV. The tribological behavior of the modified layer under dry sliding against steel was evaluated on a ring-on-block test rig. The surface-modified layer showed good friction-reducing and fair anti-wear abilities. Electrochemical corrosion experiment shows that the modified layer further improved the corrosion resistance of pump barrel.

Recovery of Metal Values From Spent Lithium-ion Batteries

Abstract: A new process involving ultrasonic separation of electrode materials, acid dissolution, precipitation of cobalt and lithium has been applied to recover metals values from spent lithium-ion batteries. The effect of organic solvent on separation of electrode decrease as the order: NMPDMFDMSOAcetone. Ultrasonic treatment can reduce the separation temperature and times. In the optimized process, electrode materials can be separated completely when ultrasonic-treated with NMP at 40℃ for 15min, 99.4% of Co and Li of separated electrode materials can be acid-leached, 99.5% of cobalt ion in acid solution can be recovered easily as spherical CoC2O4 powders, and 94.5% of Li in the surplus filtrate can be recovered as Li2CO3 after the deposition of cobalt. The LiCoO2, prepared from the recovered compounds of cobalt and lithium, is found to have good elecrtochemical performance.

Challenges and countermeasures of offshore engineering joining technology in 21st century

Abstract: Aiming at the great challenge of deepwater oil resource exploitation in 21st Century China,this paper firstly explained contents of offshore engineering joining technology,then introduced a series of important technologies such as deepwater pipeline laying welding,local dry welding,underwater hyperbaric welding,and friction stir welding,lastly put forward countermeasures to develop offshore engineering joining technology in China.

Preparation of nano-fiber supported palladium catalysts and their use for the catalytic hydrogenation of olefins

Abstract: The poly(styrene-co-acrylonitrile) supported palladium catalyst bearing a nano-fibrous morphology was prepared via electrospinning technique,and the catalyst was characterized by IR,SEM,TEM and XPS.The nano-fiber supported catalyst has high activity and good recycling property for hydrogenation of α-olefin at room temperature under 101.3 Pa.hydrogen pressure.In addition,it was found that the hydrogenation reaction of α-hexene was accompanied with the isomerization reaction.The experimental results show that the yield of the α-hexene to hexane catalyzed by the nano-fiber supported palladium catalyst was 4.7 times higher than that of PdCl_2/γ-Al_2O_3 catalyst.The hydrogenation of α-tetradecylene,cyclohexene,nitrobenzol and styrene by the nano-fiber supported palladium catalyst was also studied,the selectivity to primary products of the hydrogenation of cyclohexene,nitrobenzol and styrene was 100%.

Tribological Behaviour of the Ceramic Coating Formed on Magnesium Alloy

Abstract: Micro-arc oxidation is a recently developed surface treatment technology under anodic oxidation. Through micro-arc oxidation, a ceramic coating is directly formed on the surface of magnesium alloy, by which its surface property is significantly improved. In this paper, a dense ceramic oxide coating was prepared on an AZ31 magnesium alloy by micro-arc oxidation in a NaOH-Na2SiO3-NaB4O7-(NaPO3)6 electrolytic solution. Micro-structure, surface morphology and phase composition were analysed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The tribological behavior of the micro-arc oxidation ceramic coating under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results showed that the AZ31 alloy was characterized by adhesion wear and scuffing under dry sliding against the steel, while the surface micro-arc oxidation ceramic coating experienced much abated adhesion wear and scuffing under the same testing conditions. The micro-arc oxidation ceramic coating showed good friction-reducing and fair antiwear ability in dry sliding against the steel.

Temperature and wavelength dependence of gain and threshold current detuning with cavity resonance in vertical-cavity surface-emitting lasers

Abstract: Heating-induced threshold current detuning with different cavity resonances of AlInGaAs-AlGaAs vertical-cavity surface-emitting lasers (VCSELs) was studied based on gain spectrum analysis and threshold current construction as functions of cavity resonance wavelength and temperature. The quantitative correlations between gain peak, cavity resonance and the minimal threshold current were established. The results showed that the minimal threshold current was in agreement with the gain peak in wavelength only at the temperatures of 300-320 K. Higher temperatures led to a detuning difference between the gain peak and the minimal threshold current relative to the cavity resonance due to band-like nature of the states. In addition, this theoretical analysis about thermal tuning of the cavity resonance pointed out that the wavelength of cavity resonance shifted in an exponential function of temperature. The linear approximation was consistent with the experimental results in the temperature range 300-400 K. A new approach for the gain offsetting is provided so that the minimum in threshold currents can be aligned with the cavity resonance, instead of doing it with the gain peak to achieve the lowest threshold current of the VCSEL at a given temperature.

Preparation and characterization of Cu/SiO2 catalyst by co-gelation process

Abstract: Cu/SiO2 catalyst with bimodal pore structure was prepared by co-gelation reactions of tetramethoxysilane (TMOS) and copper nitrate in the presence of poly (ethylene oxide) (PEO) with an average molecular weight of 10,000 and the catalyst of acetic acid. In this process, the interconnected macroporous morphology was formed when transitional structures of spinodal decomposition were frozen by the sol–gel transition of silica. The addition of copper into the silica–PEO system had a negligible effect on the morphology formation. In gel formation, it was found that the crystallite sizes of the CuO estimated from the peak width in the Cu/SiO2 with the presence of PEO were not small as expected. It was considered that there was no obvious interaction between the Cu cation and PEO, most of the copper ions in wet silica gel were present in the outer solution. They easily aggregated as copper salts in the drying process of wet gel and decomposed into CuO particles in heating. While in the Cu/SiO2 with the absence of PEO, the Cu was selectively entrapped as small particles in the gel skeleton due to the interaction between Cu aqua complex and silica gel network.

A Study on Tacit Knowledge Sharing in ERP Enterprises

Abstract: With the fast developing knowledge economy, one of the major challenges facing enterprise managers is aligning knowledge management (KM) with business strategy and processes, especially after an enterprise has applied Enterprise Resource Planning (ERP). Since knowledge sharing (KnS) is one of the most critical steps in KM activities, it is necessary to study the effective sharing of tacit knowledge in ERP enterprises. In an ERP environment, KnS system should have two functions. One is to support the enterprise business and the other is to support employees’ communication. Most researches have thus far focused on the first function trying to find out management mechanism to improve the effect of KnS while ignoring the other function. In the KnS with the communication function, this research finds out that knowledge is exchanged naturally and freely. The KnS system can also make employees feel better about their work by making greater contribution to building an active culture environment to support knowledge exchange. In this paper, these two types of KnS are called business-oriented knowledge-sharing and subject-oriented knowledge-sharing. It also designs their constructions, propose their management mechanism and discuss some relevant practice problems. When these two types of KnS are applied in ERP enterprises they not only can provide channels for employees to exchange knowledge, but can also help enterprises to get tacit knowledge from ERP users and to make tacit knowledge more effectively be converted to explicit knowledge. Though ERP and KnS are performed as two separate systems, this research provides guidance to enterprise managers to develop tacit knowledge-sharing system on their ERP implementation and keep the same goal with it.

Audio watermarking algorithm based on centroid and statistical features

Abstract: Experimental testing shows that the relative relation in the number of samples among the neighboring bins and the audio frequency centroid are two robust features to the Time Scale Modification (TSM) attacks. Accordingly, an audio watermark algorithm based on frequency centroid and histogram is proposed by modifying the frequency coefficients. The audio histogram with equal-sized bins is extracted from a selected frequency coefficient range referred to the audio centroid. The watermarked audio signal is perceptibly similar to the original one. The experimental results show that the algorithm is very robust to resample TSM and a variety of common attacks. Subjective quality evaluation of the algorithm shows that embedded watermark introduces low, inaudible distortion of host audio signal.

Effect of stand-off distance on structure and mechanical properties of hydroxyapatite coatings plasma-sprayed onto carbon/carbon composites

Abstract: Plasma-spraying parameters are of crucial importance to the fabrication of high-quality hydroxyapatite (HA) coating for biomedical use In this paper, hydroxyapaptite was coated onto carbon fiber reinforced carbon composites (C/C composites) by a plasma spraying method The effect of stand-off distances on the microstructure, phase composition and shear strength of hydroxyapatite coatings was studied X-ray diffraction (XRD) was used to characterize the phase composition and scanning electron microscopy (SEM) examined the morphology of the sprayed surface and polished cross-sections The shear strength of the HA coatings–C/C substrates was detected on a RGD-5 electric tension machine The interface of the HA coating–C/C composites was also detected Results showed that the extent of melting of particles increased with increasing stand-off distances, while the crystallinity of the HA decreased at a power level of 30 kW Mechanical bonding plays a dominant role at the interface of the rough substrate and the deformed HA particles

Behavior of plasma-sprayed hydroxyapatite coatings onto carbon/carbon composites in simulated body fluid

Abstract: Two types of hydroxyapatite (HA) coatings onto carbon/carbon composite (C/C composites) substrates, deposited by plasma spraying technique, were immersed in a simulated body fluid (SBF) in order to determine their behavior in conditions similar to the human blood plasma. Calcium ion concentration, pH value, microstructure, and phase compositions were analyzed. Results demonstrated that both the crystal Ca–P phases or the amorphous HA do dissolve slightly, and the dissolution of CaO phases in SBF was evident after 1 day of soaking. The calcium-ion concentration was decreased and the pH value of SBF was increased with the increasing of the immersing time. The precipitation was mainly composed of HA, which was verified by X-ray diffraction (XRD) and electron-probe microanalyzer.

Study of pyrolysis characteristics and kinetics of Longkou oil shale

Abstract: The pyrolysis experiments of Longkou oil shale were carried out using the thermogravimetric analyzer(TGA)The effects of different heating rates on pyrolysis were investigatedThe kinetic parameters of oil shale pyrolysis were determined from TGA data by using Friedman's procedure and parallel first order reaction modelThe oil shale pyrolysis mechanism was tentatively exploredIt is found that the activation energy calculated by Friedman's procedure ranges from 100 to 200 kJ·mol-1 in the transformation ratio of 5%-95%The linear relationship between activation energy and logarithm of frequency factor was obtainedFrom the parallel reaction model,it is concluded that most reactions have the activation energy of 125-250 kJ·mol-1The pyrolysis process of oil shale can be reasonably described by these two kinetic models

Effect of water in the precursor solution on the catalytic property of LaMnAl11O19 high temperature combustion catalyst

Abstract: Manganese-substituted lanthanum hexaaluminates were prepared by the sol-gel method. The effect of water content on the catalyst preparation was examined. Large water content caused a rapid decrease in the surface area. When the R (R is the mole ratio of H2O/ Al(OC3H7)3) is equal to 1.5, the catalyst retains a specific surface area of 13.5 m2 g−1 and shows higher activity in CH4 combustion.

Deposition of SiO x on Metal Surface with a DBD Plasma Gun at Atmospheric Pressure for Corrosion Prevention

Abstract: In this study, SiOx films were deposited by a dielectric barrier discharge (DBD) plasma gun at an atmospheric pressure The relationship of the film structures with plasma powers was investigated by Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) It was shown that an uniform and cross-linking structure film was formed by the DBD gun As an application, the SiOx films were deposited on a carbon steel surface for the anti-corrosion purpose The experiment was carried out in a 01 M NaCl solution It was found that a very good anti-corrosive property was obtained, ie, the corrosion rate was decreased ca 15 times in 5% NaCl solution compared to the non-SiOx coated steel, as detected by the potentiodynamic polarization measurement

Investigation and Application of Material Used to Filtrate Pathogen

Abstract: The investigation and application of the filtration material which is used to remove pathogen was summarized in this paper.Filtration material used to remove pathogen and a technology used to produce new type of filtration material were also introduced. Moreover,principle of a removal of pathogen through filtration and the application of the filtration material,such as air cleaning,pure water production,food and medical industry were also reviewed.

A Semantic Web Service-Oriented Architecture for Enterprises

Abstract: Developing an interoperable system is one of today’s challenging issues in ubiquitous enterprise systems. Initial Web Service-Oriented solutions have enabled the use and combination of distributed functional components within and across company boundaries, but they offer only syntactical description that failed to hold the promise of automatically interacting, dynamically composed web service. Semantic Web Services (SWSs) are an extension of Web Services, with an explicit representation of meanings, to improve their usage and ease scalability. In this paper, we present a Semantic Web Service-Oriented Architecture for enterprise in which data sources and services are made available through SWSs, described by ontologies, allowing interoperability as well as reasoning to create a comprehensive response adapted to user goals, and presenting a use case scenario in the context of an apparatus market, it can also be taken into e-government consideration.