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Chen C.,University of Tulsa | Wang Y.,China University of Petroleum - East China | Li G.,University of Tulsa | Reynolds A.C.,University of Tulsa
Computational Geosciences | Year: 2010

This paper proposes an augmented Lagrangian method for production optimization in which the cost function to be maximized is defined as an augmented Lagrangian function consisting of the net present value (NPV) and all the equality and inequality constraints except the bound constraints. The bound constraints are dealt with using a trust-region gradient projection method. The paper also presents a way to eliminate the need to convert the inequality constraints to equality constraints with slack variables in the augmented Lagrangian function, which greatly reduces the size of the optimization problem when the number of inequality constraints is large. The proposed method is tested in the context of closed-loop reservoir management benchmark problem based on the Brugge reservoir setup by TNO. In the test, we used the ensemble Kalman filter (EnKF) with covariance localization for data assimilation. Production optimization is done on the updated ensemble mean model from EnKF. The production optimization resulted in a substantial increase in the NPV for the expected reservoir life compared to the base case with reactive control. © 2010 Springer Science+Business Media B.V. Source


Xiang H.F.,China University of Petroleum - East China
Applied Mechanics and Materials | Year: 2013

Improvement design was carried out to resolve the issue about easily damaged and difficult repaired planar seal for hydraulic fast connector. Through adding a taper on male connector and female regulating part on female connector, the co-planar seal was changed into the taper seal which the seal was more reliable. When the contact surface was worn, it can be resealed by adjusting the female regulating part. Taper seal was key to design the reasonable taper. In order to acquire the best taper, taper optimal design was carried out using finite element technology, the relationship between maximum contact stress and tape was gained. Simulation results showed that the best taper could be gained when the big-endian radius of the taper was 11.82 mm. © (2013) Trans Tech Publications, Switzerland. Source


Liao H.,China University of Petroleum - East China
Advanced Materials Research | Year: 2012

Rock damage and breaking mechanism with water jet has been as yet a difficult problem due to jet high turbulence and complicacy of rock material. According to fluid-structure interaction (FSI) theory, the standard k-epsilon two equations and control volume method for water jet, and the elastic orthotropic continuum and finite element method for rocks, are employed respectively to establish a numerical analyzing model of high pressure water jet impinging on rock. A damage criterion, with non-dimensional coefficient to characterize rock damage, is also set up for analyzing rock failure mechanism with water jet. The process of jet impact on the rock is simulated, by using the FSI model, Micro failure mechanism test and analysis with scanning electron microscope (SEM) for rock failure surface by jets cutting were performed, whose results show that the micromechanism of rock failure due to water jet impingement is a brittle fracture in the condition of tensile and shearing stress. The test results also agree well with the numerical simulating analysis, which constructs a bridge between the micro-failure and macro-breaking mechanism of rock with water jets impact. The investigation affords a new method for studying the mechanism of rock failure underhigh pressure water jet impingement. © (2012) Trans Tech Publications, Switzerland. Source


Zhu Y.,China University of Petroleum - East China
Lecture Notes in Electrical Engineering | Year: 2013

The current music education and teaching was developing more and more quickly. Various colleges and universities were all exploring new teaching pattern of music art major. It investigated the new teaching reform of music art in schools, economy, and other parts of different areas. And it analyzed the results of new teaching pattern of college music art from the understanding and identity of different teaching content in music teaching field thus getting the teachers and students' favorites as well as the most important and the easiest course content of the new music teaching model. This would provide some basis of the reform for the new music art teaching course. © 2013 Springer-Verlag. Source


Cui G.,China University of Petroleum - East China | Li Z.,Shandong Provincial Key Laboratory of Oil and Gas Storage and Transportation Safety | Yang C.,Circle Technology
Fuel | Year: 2016

During the production of LNG, explosion hazards may occur in the top of the distillation column in the low-temperature liquefaction of oxygen-bearing coal-bed methane. Because of the lack of flammability limits at low temperatures, in this study, an experimental setup was built to measure the flammability limits of methane/air mixtures at a wide temperature range from 123. K to 273. K and pressure range from 0.1. MPa to 0.9. MPa. The results show that the trend of flammability limits at the initial low temperature and pressure is the same as that at high temperatures. With the increase in the initial temperature or pressure, the range of flammability limit becomes wider. The upper flammability limit (UFL) or lower flammability limit (LFL) linearly correlates to temperature. The UFL shows a logarithmic trend with the initial pressure, whereas the LFL is unaffected by the initial pressure. A significant difference is observed between the flammability limits obtained in this study and other studies because of the electrode position, size of explosion vessel, and criteria for explosion. In the top of the distillation column, the methane content is within the flammability limits, and explosion hazards may occur. Therefore, proper safety measures should be taken to solve this problem. © 2016 Elsevier Ltd. Source


Gao C.,Zhejiang University | Ge Q.,Zhejiang University | Ge Q.,Huawei | Jian L.,China University of Petroleum - East China
IEEE Transactions on Fuzzy Systems | Year: 2014

Black-box models play an important role in advancing the blast furnace modeling technologies for control purposes. To further enhance their practical applications, this paper is concerned with the transparency and comprehensibility of blast furnace black-box models. A fuzzy-based support vector machine (SVM) classification algorithm is proposed to perform the tasks of determining the controllable bound from the real data, of reducing feature from extensive candidate inputs, and of training the SVM model parameters. Based on these results, a fuzzy-based blast furnace SVM three-class classifier is constructed to serve for the classification problem according to the output lower than its controlled bound, within the controlled bound and higher than the controlled bound. Further, rule extraction is made to achieve the understandability of the constructed SVM classifier. Through two typical real blast furnace cases, the extracted rules can work well in classifying the hot metal silicon content into low, proper, and high range with high transparency, as well as encouraging agreements between the predicted values and the real ones. Moreover, there needs to be very little information on the blast furnace variables when implementing every rule in practice. The extracted rules provide a more explicit and direct indication for the blast furnace operators and, thus, may serve better for decision-making with blast furnace control. © 2014 IEEE. Source


Liao H.,China University of Petroleum - East China
Advanced Materials Research | Year: 2012

It is important to make sure the stress distribution in the media under high pressure water jet as to improve jets utilities. A numerical analyzing model of stress distribution about interaction of high pressure water jets impinging solid material is established according to fluid-structure interaction theory. Standard k-ε equations model and controlled volume method for the water jets, and elastic orthotropic continuum and finite element method for the solid are adopted. The stress distributions in the fluid field and inside solid material with different water jetting velocities were computed using the model and method. Numerical results show that the stress distributes obviously on the part solid material under water jets impingement. The impinging area is subjected to compression stress, and the maximum tensile stress is located on impacting surface and the maximum shear stress being under impacting center about half nozzle diameter away. It concludes that by controlling the jet velocity and distance, jet cutting, breaking, decoating, surface processing efficiencies could be improved. © (2012) Trans Tech Publications, Switzerland. Source


Cao Y.G.,China University of Petroleum - East China | Zhang S.H.,China Institute of Technology
Engineering Failure Analysis | Year: 2013

Component analysis, metallographic examination and hardness test were performed respectively for a failed pinion and a new rack of the jacking system of a jack-up platform. Experiment results showed that the superficial heat treatment of the pinion was not uniform and there was no hardened layer at the tooth root. At the same time, the hardened layer near the pitch circle had been worn out for long-term service, thus the surface hardness of the failed pinion was lower than that of the rack. Considering that each pinion bears different load during service, the exact load that each pinion bears under the action of self-weight, variable loads and wind loads, was deduced firstly. As per the deduced bearing load of the failed pinion, elastic FEM analysis was performed and the distribution of stresses on the rack and pinion was simulated when the platform was under preload condition. By comparing the Von mises stresses and contact stresses with those calculated according to the formula, the accuracy of FEM analysis was verified. Then elastic-plastic FEM analysis was performed for pinion models with hardened layer and without hardened layer respectively, the results were used to explain the failure of the pinion. © 2013 Elsevier Ltd. Source


Sun Q.,University of Queensland | Wang M.,University of Queensland | Wang M.,China University of Petroleum - East China | Li Z.,University of Wollongong | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2014

Capturing and sequestering carbon dioxide (CO2) can provide a route to partial mitigation of climate change associated with anthropogenic CO2 emissions. Here we report a comprehensive theoretical study of CO2 adsorption on two phases of boron, α-B12 and γ-B28. The theoretical results demonstrate that the electron deficient boron materials, such as α-B12 and γ-B 28, can bond strongly with CO2 due to Lewis acid-base interactions because the electron density is higher on their surfaces. In order to evaluate the capacity of these boron materials for CO2 capture, we also performed calculations with various degrees of CO2 coverage. The computational results indicate CO2 capture on the boron phases is a kinetically and thermodynamically feasible process, and therefore from this perspective these boron materials are predicted to be good candidates for CO2 capture. This journal is © the Partner Organisations 2014. Source


Li S.,China University of Petroleum - East China
Materials Science Forum | Year: 2011

Atomic Environment Calculation (AEC) is a computation method for calculating atomic environment properties of every atom in any crystal. These properties include types of neighboring atoms and their spatial distribution, bond lengths sorted in an ascending order, atomic space coordination number, and atomic pair coordination number. AEC can output bond data for each type of atom, which is equivalent to giving a description of local cluster structure in the crystal. AEC can also be used to optimize the coordinates of the atoms in the crystal and assemble atoms into simple crystals. AEC calculates atomic environment by means of operating atoms in point groups and self-consistent calculation of coordinate. Any accidental and systematic errors in crystal structure data can be corrected by AEC. © (2011) Trans Tech Publications. Source


Liu D.-Y.,CAS Hefei Institutes of Physical Science | Quan Y.-M.,CAS Hefei Institutes of Physical Science | Chen D.-M.,China University of Petroleum - East China | Zou L.-J.,CAS Hefei Institutes of Physical Science | Lin H.-Q.,Chinese University of Hong Kong
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

In this paper we explore the magnetic and orbital properties in iron pnictides based on the two-orbital as well as the five-orbital Hubbard models. These properties are closely related to a tetragonal-orthorhombic structural phase transition. The electron-lattice coupling, interplaying with electron-electron interaction, is self-consistently treated. Our results reveal that the orbital polarization favors the spin-density wave (SDW) in the orthorhombic phase. The ferro-orbital (FO) order only occurs in the orthorhombic phase rather than in the tetragonal one. For the five-orbital model, magnetic moments of Fe are small in the intermediate Coulomb interaction region in the striped antiferromagnetic phase. We also calculate the Fermi surface, which is anisotropic in the SDW/FO orthorhombic phase and agrees well with the recent angle-resolved photoemission spectroscopy experiments. These results suggest that the magnetic phase transition is driven by the FO order arising from the electron-lattice coupling. © 2011 American Physical Society. Source


Zhao X.,Bohai University | Zhao X.,China University of Petroleum - East China | Zhang L.,Harbin Institute of Technology | Wang Z.,Harbin Institute of Technology
IET Control Theory and Applications | Year: 2012

This brief concerns the stabilisation problem for a class of slowly switched positive linear systems in discrete-time context. The average dwell-time switching associated with the corresponding state-feedback controllers is designed to stabilise the closed-loop systems and keep the states non-negative. The developed conditions are formulated as linear matrix inequalities, which can be directly used for controller synthesis and switching designing. Finally, a numerical example is presented to show the feasibility of the obtained theoretical results. © 2012 The Institution of Engineering and Technology. Source


Sheng L.,China University of Petroleum - East China | Gao M.,Shandong University of Science and Technology | Zhang W.,Shandong University of Science and Technology
International Journal of Systems Science | Year: 2014

The dissipative analysis and control problems for a class of Markov jump non-linear stochastic systems (MJNSSs) are investigated. A sufficient condition for the dissipativity of MJNSSs is given in terms of coupled non-linear Hamilton-Jacobi inequalities (HJIs). Generally, it is difficult to solve the coupled HJIs. In this paper, based on T-S fuzzy model, the dissipative analysis and controller design for MJNSSs is proposed via solving a set of linear matrix inequalities (LMIs) instead of HJIs. Finally, a numerical example is presented to show the effectiveness of the proposed method. © 2012 Taylor & Francis. Source


Zhou X.,PLA Fourth Military Medical University | Liu J.,China University of Petroleum - East China
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2013

The stability of short DNA ring is phenomenologically analyzed by discussing the second variation of its elastic free energy. Through expanding the perturbation functions as Fourier series, the DNA ring's stability condition is obtained in a general case. This result is also suitable for other structures which can be taken as one-dimensional (1D) curvature elastomers, such as ribbons and filaments. Stability analysis in a typical model provides some useful results which are consistent with the experimental observations in a wide parameter range. © 2012 Elsevier B.V. All rights reserved. Source


Gao M.,Shandong University of Science and Technology | Sheng L.,China University of Petroleum - East China | Zhang W.,Shandong University of Science and Technology
IET Control Theory and Applications | Year: 2014

This study investigates the finite horizon H2/H ∞ control of time-varying stochastic Markov jump systems (SMJSs) with state, control and disturbance-dependent noise. Firstly, the stochastic bounded real lemma of SMJSs is established, which by itself has theoretical importance. Secondly, several necessary and sufficient conditions for H2/H∞ control of SMJSs are proposed by means of coupled generalised differential Riccati equations. Finally, two numerical examples are given to show the effectiveness of the obtained results. © The Institution of Engineering and Technology 2014. Source


Liu B.-D.,China University of Petroleum - East China | Wang Y.-X.,Carnegie Mellon University | Shen B.,Purdue University | Zhang Y.-J.,Tsinghua University | Hebert M.,Carnegie Mellon University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

Traditional sparse representation algorithms usually operate in a single Euclidean space. This paper leverages a self-explanatory reformulation of sparse representation, i.e., linking the learned dictionary atoms with the original feature spaces explicitly, to extend simultaneous dictionary learning and sparse coding into reproducing kernel Hilbert spaces (RKHS). The resulting single-view self-explanatory sparse representation (SSSR) is applicable to an arbitrary kernel space and has the nice property that the derivatives with respect to parameters of the coding are independent of the chosen kernel. With SSSR, multiple-view self-explanatory sparse representation (MSSR) is proposed to capture and combine various salient regions and structures from different kernel spaces. This is equivalent to learning a nonlinear structured dictionary, whose complexity is reduced by learning a set of smaller dictionary blocks via SSSR. SSSR and MSSR are then incorporated into a spatial pyramid matching framework and developed for image classification. Extensive experimental results on four benchmark datasets, including UIUC-Sports, Scene 15, Caltech-101, and Caltech-256, demonstrate the effectiveness of our proposed algorithm. © 2014 Springer International Publishing. Source


Chen W.,China University of Petroleum - East China | Chen J.,Sinopec
Fuel | Year: 2016

Crystallization behaviors of biodiesel including measurement and modeling the amount of precipitated crystal at different temperatures were studied. The amount of crystal precipitated from biodiesel at different temperatures was measured by differential scanning calorimeter (DSC) according to the method, which was established in this work. Comparison of model predictions and DSC experimental data shows that the amount of precipitated crystal predicted by regular solution model agrees well with the experimental results. The critical strain and storage modulus in linear region of biodiesel gels at different temperatures were obtained by studying the yielding process of gelled biodiesels using controlled stress rheometer. Based on Wu-Morbidelli scaling model, the microstructure fractal dimensions were obtained and the fractal structures of biodiesel gels were studied by establishing the relationship between the rheological parameters and the amount of precipitated crystals. The experimental results show that with the increase of amount of precipitated crystals, the storage modulus in linear region increases and the critical strain decreases. Meanwhile, these two parameters display a power-law relationship with the amount of precipitated crystal. Based on Wu-Morbidelli model, the biodiesel gels are in the transition zone. The results obtained by scaling model display that the fractal dimensions of biodiesel gels increase with decrease in temperature. It is suggested that the microstructure of biodiesel gels is porous at relatively high temperatures and the structure is relatively compact at relatively low temperatures. It was found that fractal dimensions were not influenced by the composition of biodiesels. © 2015 Elsevier Ltd. All rights reserved. Source


Che C.,China University of Petroleum - East China
International Review on Computers and Software | Year: 2012

To the problem of boycott during the execution of marketing audit, the paper firstly introduces the related research of scholars at home and abroad. Secondly, to the deficiencies of the previous studies, the game analysis of both parties of the boycott is used to find out the solutions which can reduce the boycott. Finally, the paper proposes five solutions to solve the problem effectively. © 2012 Praise Worthy Prize S.r.l. - All rights reserved. Source


He X.,China National Petroleum Corporation | Lei Y.,China University of Petroleum - East China
International Review on Computers and Software | Year: 2012

To solve optimal control problems with numerical methods, a hybrid wavelet neural network - particle swarm optimization algorithm is proposed. Firstly, the hybrid algorithm is to parameterize the optimal control trajectory based on the non-linear approximation capability of the wavelet neural network. Then the optimal control problem is transformed into a non-linear programming problem where the decision variables are the parameters of the wavelet neural network. Finally, the parameters of the network are optimized by the particle swarm optimization algorithm and the global optimal solution of the NLP is obtained. Simulation study on a benchmark chemical process optimal control problem shows the feasibility and effectiveness of the proposed method. © 2012 Praise Worthy Prize S.r.l. - All rights reserved. Source


Zhao X.,China University of Petroleum - East China | Shi P.,Victoria University of Melbourne | Shi P.,University of Adelaide | Zhang L.,Harbin Institute of Technology
Systems and Control Letters | Year: 2012

The stabilization problem for a class of switched linear systems with average dwell time (ADT) switching is reinvestigated in this paper. State-feedback controllers are designed, which takes the more practical case, asynchronous switching, into account, where the so-called "asynchronous switching" indicates that the switchings between the controllers and the system modes are in the presence of a time delay. By combining the asynchronous switching, an improved stabilization approach is given, and existence conditions of the controllers associated with the corresponding ADT switching are formulated in terms of a set of linear matrix inequalities. A numerical example is given to show the validity and potential of the obtained theoretical results. © 2012 Elsevier B.V. All rights reserved. Source


Zhang D.,University of Minnesota | Zhang D.,China University of Petroleum - East China | Cui T.,University of Minnesota
Sensors and Actuators, A: Physical | Year: 2012

This paper presents layer-by-layer (LbL) self-assembly of single-walled carbon nanotube (SWNT)/polymer membranes with a well-dispersed wide-range tunable volume fraction of functionalized SWNTs. The surface morphology of the SWNT/polymer membranes shows a high strength, dense and random network structures. The quartz crystal microbalance (QCM) characterization illustrates that the deposition thickness and the SWNT loading fraction in SWNT nanocomposites can be controlled in a large range based on LbL sequential deposition process. The Young's modulus of the self-assembled SWNT/polymer composite membranes is characterized by a combinative approach of piezoelectric excitation and laser vibrometer measurement. The Young's modulus of SWNT/polymer nanocomposites is tunable from hundreds to tens of GPa, as a function of the SWNT volume fraction. Such significant enhancement of LbL self-assembled SWNTs offers a way in which the embedded SWNTs can realize the true potential to strengthen SWNT/polymer nanocomposites. Conventional mixture models such as rule-of-mixture model and Halpin-Tsai model fail to explain the structure-property regime in nanoscale at a high SWNT fraction ratio. This observed tunability can serve as a benchmark to tailor the design of nanocomposite thin films for potential applications to MEMS and NEMS devices. © 2012 Elsevier B.V. Source


Liu L.G.H.,China University of Petroleum - East China
7th EAGE Saint Petersburg International Conference and Exhibition: Understanding the Harmony of the Earth's Resources Through Integration of Geosciences | Year: 2016

The purpose of this article is to provide awareness of the subtle difference among these three sections shale.In order to figure out the exquisite distinction, nearly 200 samples have been used in a series of integrated and repeatable methods, including XRD, SEM-EDS, trace elements analysis, TOC and ROCK-EVAL.II Methodology, Vitrinite reflectance analysis, N2 adsorption analysis, CH4 adsorption analysis, and rock property analysis. Source


Zhang P.-Y.,China University of Petroleum - East China
Applied Mechanics and Materials | Year: 2013

Word similarity computation is broadly used in many applications, such as information retrieval, information extraction, text categorization, word sense disambiguation and example-based machine translation and so on. The main obstacle of word similarity computation lie in that how to develop a computational algorithm that is capable of generating satisfactory results close to how human perceive. This paper proposed an approach of word similarity computation which combined WordNet and HowNet. Experiments on Chinese word pairs show that our method is closest to human similarity judgments when compared to the major state-of-art methods. © (2013) Trans Tech Publications, Switzerland. Source


Yu Z.-X.,Beijing Information Science and Technology University | Jiao Z.Y.,China University of Petroleum - East China
International Journal of Theoretical Physics | Year: 2010

By using of the invariant theory, we have studied the geometric phase of quantum dots in the time-dependent isotropic magnetic field, the dynamical and geometric phases are given, respectively. © Springer Science+Business Media, LLC 2010. Source


Jiang Y.,China University of Petroleum - East China | Gao X.,Zhejiang University | Wu W.,Zhejiang University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

V2O5/TiO2 catalysts were prepared by an impregnation method. Effects of H2O and SO2 on the performance of the catalysts were investigated in the selective catalytic reduction of NO with NH3. The results show that H2O exhibits an inhibiting effect on the selective catalytic reduction (SCR), but it reduces the formation of N2O. SO2 has no large impact on the activity of NO reduction over the catalysts in dry or wet simulated flue gas (ψ(H2O)=10%). The presence of H2O increases the amount of the Brønsted acid sites on the catalysts' surface, thereby increasing the amount of adsorbed NH3. The deNOx activity decreases with the increase of the volume fraction of H2O in flue gas. The reason is that a large amount of H2O depressed the reaction of NO with NH4 + adsorbed on Brønsted acid sites. SO2 is transformed to SO4 2- over the catalysts' surface. SO4 2- can enhance the acidity of the catalysts' surface, thereby increasing the speed of SCR reaction. © 2013 Chinese Society for Electrical Engineering. Source


Jiang Y.,China University of Petroleum - East China | Gao X.,Zhejiang University | Wu W.,Zhejiang University | Zhang Y.,Zhejiang University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

A review of the deactivation of selective catalytic reduction (SCR) deNOx catalysts was presented based on catalyst sintering, abrasion, blocking, fouling/masking and poisoning. The law and mechanism of catalyst deactivation was reviewed. The effect of fly ash in flue gas on the catalysts is critical in the SCR deNOx process. According to the application of SCR deNOx catalysts, the catalyst deactivation rate can be decreased by optimizing boiler operation, the design of SCR deNOx system, catalyst performance, and so on. Source


Liu W.,China University of Petroleum - East China | Tao D.,Intelligent Systems Technology, Inc.
IEEE Transactions on Image Processing | Year: 2013

The rapid development of computer hardware and Internet technology makes large scale data dependent models computationally tractable, and opens a bright avenue for annotating images through innovative machine learning algorithms. Semisupervised learning (SSL) therefore received intensive attention in recent years and was successfully deployed in image annotation. One representative work in SSL is Laplacian regularization (LR), which smoothes the conditional distribution for classification along the manifold encoded in the graph Laplacian, however, it is observed that LR biases the classification function toward a constant function that possibly results in poor generalization. In addition, LR is developed to handle uniformly distributed data (or single-view data), although instances or objects, such as images and videos, are usually represented by multiview features, such as color, shape, and texture. In this paper, we present multiview Hessian regularization (mHR) to address the above two problems in LR-based image annotation. In particular, mHR optimally combines multiple HR, each of which is obtained from a particular view of instances, and steers the classification function that varies linearly along the data manifold. We apply mHR to kernel least squares and support vector machines as two examples for image annotation. Extensive experiments on the PASCAL VOC'07 dataset validate the effectiveness of mHR by comparing it with baseline algorithms, including LR and HR. © 1992-2012 IEEE. Source


Li Y.,China University of Petroleum - East China
Advanced Materials Research | Year: 2013

With the extensive applications of FFT in digital signal processing and image signal processing which needs a extensive application of large-scale computing, it become more and more important to improve parallelism, especially efficient and scalable parallel of FFT algorithm. This paper improves the parallelism of the FFT algorithm based on the Six-Step FFT algorithm. The introduction of GPU to parallel computing is to realize parallel FFT computing in a single machine and to improve the speed of Frontier transform. With the optimization strategy of the mapping hiding the transport matrix, the performance of parallel FFT algorithm after optimization is remarkably promoted by the assignment of matrix calculation and butterfly computation to GPU. Finally it applies to design the digital filter in seismic data. © (2013) Trans Tech Publications, Switzerland. Source


Wang M.-B.,China University of Petroleum - East China
Advanced Materials Research | Year: 2012

This paper gives an overview of erosion mechanisms in elbows in oil and gas production systems. The nature of the erosion process itself makes it very difficult to develop some definitive methods or models to prevent or predict the erosion in elbows in all conditions. This paper provides a review of the subject which will help petroleum engineers to handle the erosion problems in oil and gas industry. This review is given of different erosion mechanisms connected with sand erosion and the factors that influence them, and then the review goes on to look at particulate erosion in elbows in more details. Conclusions are then drawn based on the above analyses. © (2012) Trans Tech Publications. Source


Yang G.,China University of Technology | Yang B.,China University of Technology | Xiao T.,University of Oxford | Yan Z.,China University of Petroleum - East China
Applied Surface Science | Year: 2013

One-step solvothermal method was developed for the synthesis of hierarchically porous nanostructured CdS/TiO2 heterojunction materials, which exhibited enhanced visible-light-driven photocatalytic activity in decomposing both methyl orange (MO) and rhodamine B (RhB) in water. The photocatalyst with the highest performance was the one prepared using the Ti:Cd molar ratio of 1:1. Based on the characterization results of XRD, XPS, FT-IR, SEM, HRTEM, UV-vis DRS and N2 adsorption-desorption, the influence of coupling TiO2 with CdS on the crystal phase, band structure, surface element composition, morphology, optical absorption and surface area of the as-prepared samples are investigated. The results showed that the CdS/TiO 2 heterojunction catalysts possessed well-defined hierarchically porous structure composed of anatase TiO2 and hexagonal CdS nanoparticle with average grain size of 4-6 nm. Their enhanced catalytic activity can be attributed to the synergistic effect of crystal compositions, porous architectures, electronic band structure, large specific surface area and strong visible light absorption. © 2013 Elsevier B.V. All rights reserved. Source


Zhao X.,Bohai University | Zhao X.,China University of Petroleum - East China | Liu H.,Harbin Institute of Technology | Zhang J.,Shanghai JiaoTong University | Li H.,Bohai University
IEEE Transactions on Automation Science and Engineering | Year: 2015

In this paper, the problems of state estimation are investigated for switched linear systems with average dwell time (ADT) switching in both continuous-time and discrete-time contexts. First, a set of mode-dependent Luenberger-type observers is designed subject to the ADT switching that is synchronous with the switching of the estimated systems. Then, a more practical case of the delayed observers is also considered, which implies that the switching of the multiple-mode observer to be designed has a lag to the switching of the estimated systems. In this case, the asynchronous switching signals are combined as a preliminary attempt, upon which sufficient conditions for the existence of the Luenberger-type observers and the corresponding ADT switching are formulated in terms of a set of linear matrix inequalities. Finally, the proposed approaches are applied to the state estimation of electronic circuits to demonstrate the effectiveness and applicability. © 2004-2012 IEEE. Source


Ge H.,Tongji University | Zhang C.L.,Tongji University | Zhang C.L.,University of Georgia | Dang H.,China University of Petroleum - East China | And 2 more authors.
Geoscience Frontiers | Year: 2013

Archaea have unique glycerol dialkyl glycerol tetraether (GDGT) lipids that can be used to develop paleotemperature proxies such as TEX86. This research is to validate proposed GDGT-proxies for paleotemperature determination in the South China Sea (SCS). Samples were collected from core-top sediments (0-5 cm) in the northern SCS. Total lipids were extracted to obtain core GDGTs, which were identified and quantified using liquid chromatography-mass spectrometry (LC-MS). The abundance of isoprenoidal GDGTs (iGDGTs) ranged from 271.5 ng/g dry sediment to 1266.3 ng/g dry sediment, whereas the branched GDGTs (bGDGTs), supposedly derived from terrestrial sources, ranged from 22.2 ng/g dry sediment to 56.7 ng/g dry sediment. The TEX86-derived sea surface temperatures ranged from 20.9 °C in the coast (water depth < 160 m) to 27.9 °C offshore (water depth > 1000 m). TEX86-derived temperatures near shore (<160 m water depth) averaged 23.1 ± 2.5 °C (n = 4), which were close to the satellite-derived winter mean sea surface temperature (average 22.6 ± 1.0 °C, n = 4); whereas the TEX86-derived temperatures offshore averaged 27.4 ± 0.3 °C (n = 7) and were consistent with the satellite mean annual sea surface temperature (average 26.8 ± 0.4 °C, n = 7). These results suggest that TEX86 may record the sea surface mean annual temperature in the open ocean, while it likely records winter sea surface temperature in the shallower water. © 2012, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved. Source


Li X.,University of Regina | Zhang J.,China University of Petroleum - East China | Yang D.,University of Regina
Industrial and Engineering Chemistry Research | Year: 2012

A systematic technique has been developed to determine antiscaling efficiency and dissolution capacity for calcium carbonate in oilfield brines under various ultrasonic treating conditions. During the static experiments, effects of ultrasonic frequency, acoustic intensity, treating time, and water level on the antiscaling efficiency have been evaluated, while the underlying antiscaling mechanism is identified and determined. Physically, the formation of calcium carbonate is promoted as a result of the decreased molecular force and accelerated movement of salty ions under ultrasonic irradiation. Most of the formed scale is found to loosely suspend in the liquid, rather than tightly adhere to the solid surface. During the dynamic experiments, orthogonal tests have been designed to examine effects of interval time, treating time, and flow velocity on antiscaling efficiency. As for the dissolution experiment, dissolution capacity is measured to evaluate the effect of ultrasonic frequency on dissolution of the formed calcium carbonate. The antiscaling efficiency is found to achieve its maximum value of 81.1%, using the ultrasonic treatment with a frequency of 28 kHz, an acoustic intensity of 0.61 W/cm 2, an interval time of 2 h, a treatment time of 15 min, and a flow velocity of 1.8 m/s. It is also found that dissolution capacity does not impose a dominant effect on scale prevention and that the highest dissolution capacity of 19.3% is obtained with an ultrasonic frequency of 28 kHz. © 2012 American Chemical Society. Source


Guo C.,Missouri University of Science and Technology | Xu J.,China University of Petroleum - East China | Wu K.,University of Calgary | Wei M.,Missouri University of Science and Technology | Liu S.,Missouri University of Science and Technology
Fuel | Year: 2014

Unlike conventional gas reservoirs, gas flow in shale reservoirs is a complex and multiscale flow process which has special flow mechanisms. Shale gas reservoirs contain a large fraction of nano pores, which leads to an apparent permeability that is dependent on pore pressure, fluid type, and pore structure. Study of gas flow in nano pores is essential for accurate numerical simulation of shale gas reservoirs. However, no comprehensive study has been conducted pertaining to the gas flow in nano pores. In this paper, experiments for nitrogen flow through nano membranes (with pore throat size: 20 nm, 55 nm, and 100 nm) have been done and analyzed. Obvious discrepancy between apparent permeability and intrinsic permeability has been observed; and the relationship between this discrepancy and pore throat diameter (PTD) has been analyzed. Then, based on the advection-diffusion model, a new mathematical model has been constructed to characterize gas flow in nano pores. A new apparent permeability expression has been derived based on advection and Knudsen diffusion. A comprehensive coefficient for characterizing the flow process was proposed. Simulation results were verified against the experimental data for gas flow through nano membranes and published data. By changing the comprehensive coefficient, we found the best candidate for the case of argon with a membrane PTD of 235 nm. We verified the model using experimental data with different gases (oxygen, argon) and different PTDs (235 nm, 220 nm). The comparison shows that the new model matches the experimental data very closely. Additionally, we compared our results with experimental data, the Knudsen/Hagen-Poiseuille analytical solution, and existing models available in the literature. Results show that the model proposed in this study yielded a more reliable solution. Shale gas simulations, in which gas flowing in nano pores plays a critical role, can be made more accurate and reliable based on the results of this work. © 2014 Elsevier Ltd. All rights reserved. Source


He X.,Anhui University of Technology | Li R.,Anhui University of Technology | Han J.,Anhui University of Technology | Yu M.,Anhui University of Technology | Wu M.,China University of Petroleum - East China
Materials Letters | Year: 2013

Mesoporous carbons (MCs) with high surface area of 1409-1552 m2 g-1 for supercapacitors were prepared from peanut shell by one-step microwave-assisted ZnCl2 activation. The MC made at the ZnCl 2/peanut shell mass ratio of 4 in 20 min at 600 W microwave power (nominated as MC4-M) retains a high specific capacitance of 184 F g-1 at 0.05 A g-1 current density after 1000 cycles, showing perfect cycle stability. At 1.6 A g-1 current density, the energy density of the supercapacitor made from MC4-M reaches 4.94 Wh kg-1 at 740 W kg-1, exhibiting excellent rate performance. The findings clearly indicate that the one-step microwave-assisted ZnCl 2 activation technique is a facile approach to the preparation of high performance MCs for supercapacitors. © 2012 Elsevier B.V. All rights reserved. Source


Yang G.,China University of Technology | Yang G.,University of Oxford | Yan Z.,China University of Petroleum - East China | Xiao T.,University of Oxford | Yang B.,China University of Technology
Journal of Alloys and Compounds | Year: 2013

In this study, a series of alkalis doped TiO2 (alkalis = Na, K and Rb) photocatalysts were synthesized at low temperature using solvothermal method. Various characterization techniques, such as X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectra (FT-IR), Scanning electron microscopy (SEM), N2 adsorption and UV-vis diffuse reflectance spectra (DRS) spectrophotometer, were employed to investigate the influence of alkali ions on the crystalline phase, grain size, optical absorption and surface functional groups of alkali ion doped TiO2 catalysts. The XRD results indicate that the alkali ion doping restrains the growth of the TiO2 particle size, resulting in a high specific surface area for the alkali ion doped TiO2 materials. The photocatalytic performances of these materials were evaluated using the degradation of methyl orange (10 mg/L) as the model reaction under UV light irradiation. It was found that the photocatalytic activity of the alkali ion doped TiO2 catalysts can be enhanced significantly with the samples doped by 3 wt% alkali ion, which is due to the synergistic effect of pure anatase TiO2 phase structure, small crystallite size, higher surface basic sites and fast electronic transfer rate. Source


Ding Y.,Shandong University | Ding Y.,University of Jinan | Shen S.Z.,CSIRO | Sun H.,China University of Petroleum - East China | And 3 more authors.
Sensors and Actuators, B: Chemical | Year: 2014

l-Glutathione capped (GSH) ZnSe quantum dots (QDs) have been synthesized as a fluorescence ions probes for ultrasensitive Cu (II) detection. These QDs surface decoration with glutathione shells can be directly applied without previous treatment. The fluorescence quenching of the GSH-capped-ZnSe QDs depends on the concentration, pH values and reaction time of the Cu2+ solution. Based on the effective electron transfer from GSH to Cu2+ and the surface ligand stripping occurs onto the surface of ZnSe QDs, it results in the reduction of Cu2+ to Cu+ and increment of surface defection on the surface of the QDs. Under the optimum conditions, the detection limit of Cu2+ is 2 × 10-10 mol L-1. Meanwhile, the effect of foreign ions displays a low interference response in the detecting of Cu2+ ions. Moreover, based on the invariable absorption peak position and curtate luminescence lifetime of ZnSe QDs, the quenching process has also been confirmed to be a dynamic quenching procedure. With regard to the practical feasibility test of the fluorescent probe, a relative lower standard deviation (RSD) (≤3%) and a high recovery rate demonstrate that the proposed simple method is sensitive, accurate and reliable. © 2014 Elsevier B.V. Source


Chen H.,CAS National Astronomical Observatories | Zhang J.,CAS National Astronomical Observatories | Cheng X.,Nanjing University | Ma S.,China University of Petroleum - East China | And 2 more authors.
Astrophysical Journal Letters | Year: 2014

Using multi-wavelength data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, we investigated two successive solar flares, a C5.1 confined flare and an X4.9 ejective flare with a halo coronal mass ejection, in NOAA active region 11990 from 2014 February 24 to 25. Before the confined flare onset, EUV brightening beneath the filament was detected. As the flare began, a twisted helical flux rope (FR) wrapping around the filament moved upward and then stopped, and in the meantime an obvious X-ray source below it was observed. Prior to the ejective X4.9 flare, some pre-existing loop structures in the active region interacted with each other, which produced a brightening region beneath the filament. Meanwhile, a small flaring loop appeared below the interaction region and some new helical lines connecting the far ends of the loop structures were gradually formed and continually added into the former twisted FR. Then, due to the resulting imbalance between the magnetic pressure and tension, the new FR, together with the filament, erupted outward. Our observations coincide well with a tether-cutting model, suggesting that the two flares probably have the same triggering mechanism, i.e., tether-cutting reconnection. To our knowledge, this is the first direct observation of tether-cutting reconnection occurring between pre-existing loops in an active region. In the ejective flare case, the erupting filament exhibited an Ω-like kinked structure and underwent an exponential rise after a slow-rise phase, indicating that the kink instability might be also responsible for the eruption initiation. © 2014. The American Astronomical Society. All rights reserved. Source


Wang D.,Xian Jiaotong University | Liang F.-C.,China University of Petroleum - East China | Peng Z.-Q.,Xian Jiaotong University | Wang Y.-G.,Xian Jiaotong University | Lin Z.-H.,Xian Jiaotong University
International Journal of Multiphase Flow | Year: 2012

This paper presents a gas-liquid two-phase flow measurement method by sampling a very small fraction (5%) of the total flow. Unlike the conventional sample technique, the sample is drawn from the whole cross section instead of a local place. During the sampling, a discrete total two-phase flow sample is extracted by a sampling device and separated into single phase flows with a much small separator, and they are subsequently metered by two single phase flowmeters respectively, after that, these two streams will return to the main stream. The sample is able to represent the total flow and accurately determine the total flowrates. Because the sample is only a very small fraction of the total flow, the separator can be greatly reduced in size, which can be as small as a single phase flowmeter. At the same time, considering the flow has become two single phase streams after the separation, the measurement reliability is significantly improved. Experiments were conducted in an air-water two phase flow test loop. The inner pipe diameter of the test loop was 50. mm, and the superficial gas velocity varied from 1.5. m/s to 22. m/s, the liquid superficial velocity was in the range of 0.02-0.45. m/s. The flow pattern occurring during the experiments included stratified flow, stratified wave, slug flow and annular flow. The experimental results showed that this sampling method was feasible of measurin. g the two phase flowrates, and independent of flow pattern, the error of flowrates measurements was less than ±5%. © 2011 Elsevier Ltd. Source


Chen L.,China University of Petroleum - East China | Zhang X.,Yangzhou University
Tenside, Surfactants, Detergents | Year: 2013

This paper evaluated the oil displacing performance of novel surfactants called dodecyl polyoxyethylene ethers sulfonates (AESO) at high-temperature, high-salinity and low-permeability reservoir conditions. We found that AESO-9 and AESO-12 with better thermal stability could create ultra-low interfacial tension (IFT) at high-temperature and high-salinity conditions, and the IFT was largely independent of both temperature and salinity. Compared to AES-12, temperature and salinity had much less effect on the emulsification property of AESO-12. The dynamic equilibrium adsorption capacity of AESO-12 was only 0.09 mg/g sand at 90 °C. The incremental recovery by only using AESO-12 could attain 8.81 % at difficult conditions. When the core permeability decreased to 2.67 × 10-3 μm2, the incremental recovery by using the composite oil displacement agents based on AESO-12 could still attain 10.98% at the temperature of 90°C and the salinity of 60g/L. In brief, AESO-12 exhibits excellent oil-displacement capacity at high-temperature, high-salinity and low-permeability reservoir conditions. Source


Li S.,Nanjing Southeast University | Wang Z.,Nanjing Southeast University | Wang Z.,China University of Petroleum - East China | Fei S.,Nanjing Southeast University
Aerospace Science and Technology | Year: 2011

In a recent paper by Jin Erdong and Sun Zhaowei [Robust controllers design with finite time convergence for rigid spacecraft attitude tracking control, Aerospace Science and Technology 12 (2008) 324-330], a terminal sliding mode control technique has been applied to the attitude control problem of rigid spacecraft. Unfortunately, the controller has singularity problem which will cause the instability of the closed-loop system of attitude tracking errors. In this article, a nonsingular terminal sliding mode controller is presented to overcome this problem. © 2010 Elsevier Masson SAS. Source


Xu K.,Coastal Carolina University | Li A.,CAS Qingdao Institute of Oceanology | Liu J.P.,North Carolina State University | Milliman J.D.,College of William and Mary | And 5 more authors.
Marine Geology | Year: 2012

Surficial grain-size and down-core clay mineralogical data show that sediment along the inner-most part of the continental shelf in East China Sea is mainly derived from the Yangtze River (Changjiang), spanning from the Yangtze mouth (33°N) ~. 1000. km southward to the southwestern corner of the Taiwan Strait (24°N). High-resolution CHIRP seismic profiles reveal an elongated mud wedge extending along the inner shelf, with a northern depocenter on the modern Yangtze delta and a southern depocenter at 27.5°N. Four distinct acoustic units are delineated within the mud wedge (from bottom up): unit I (late-Pleistocene, mainly valley fills), unit II (formed by transgressions, thin strata), unit III (11-2. kyr BP, downlapping strata) and unit IV (2-0. kyr BP, flat and opaque strata). Incised valleys, up to 15-m deep, are filled by flat-lying or inclined strata in unit I. The thin (<3 m) and acoustically transparent unit II is only seen between 30 and 26°N in water depths between 40 and 90. m. Separated by acoustically opaque strata or unconformities, units III and IV are widely distributed. During the past 11. kyr Yangtze sediment accumulation has been unsteady, showing two high and one low accumulation-rate periods. The high-accumulation period at 5-8. kyr BP may be related to maximum East Asian summer monsoon precipitation in the Yangtze basin; the other high-accumulation period, 0-2. kyr BP, probably reflects intensive human activities in the river's watershed. The low-accumulation-rate period at 2-5. kyr BP, which is seen in both northern and southern Yangtze depocenters, is probably related to low river discharge and/or intensified Taiwan Warm Current and China Coastal Current. © 2011 Elsevier B.V.. Source


Yang C.,China University of Petroleum - East China
International Journal of Computer Mathematics | Year: 2014

We present error analysis of fully discrete Galerkin finite element methods for the time-dependent Ginzburg-Landau equations with the temporal gauge, where a linearized backward Euler scheme is used for the time discretization. We prove that the convergence rate is O(τ+hr) if the finite element space of piecewise polynomials of degree r is used. Due to the degeneracy of the problem, the convergence rate is one order lower than the optimal convergence rate of finite element methods for parabolic equations. Numerical examples are provided to support our theoretical analysis. © 2013 © 2013 Taylor & Francis. Source


Tang D.,China University of Petroleum - East China
1st CCPS Asia-Pacific Conference on Process Safety 2013, APCPS 2013 | Year: 2013

Facing the severe security situation in the oil industry, it has been becoming scholars' research priority about how to strengthen the safety culture construction of petroleum enterprise, particularly how to conduct effective performance management of safety culture construction. As a performance proposal method which can give a comprehensive examination of various factors affecting the performance, the balanced scorecard became an effective tool of the performance management of safety culture construction in petroleum enterprises. The main contents of the thesis include (1) Summarizing the current situation of performance management of safety culture construction in petroleum cntcrprises.(2) Introducing the basic theory of the balanced scorecard and analyzing its applicability in performance evaluation of safety culture construction of petroleum enterprises. (3) According to the characteristics and requirements of the performance management of safety culture construction in petroleum enterprises, modulating the four dimensions of the balanced scorecard into the security dimension, the social satisfaction dimension, the internal management dimension, and the learning and growth dimension. The paper also sets the corresponding indicators for each dimension. The security dimension indicators include production accident rate, personnel casualty rate, and violating operation rate. The social satisfaction dimension indicators include government satisfaction, investment party satisfaction, and employees' families' satisfaction. The internal management indicators include security concept identity rate, security activities participation rate, and security system implementation force. The learning and growth dimension degrees indicators include training expenditures, training time, and supportive learning environment. (4) Introducing the calculation and application method of performance results of petroleum enterprises safety culture construction. Based on the practice of performance management of safety culture construction in petroleum enterprises and the balanced scorecard, the performance measurement system of safety culture construction in petroleum enterprises is of strong pertinence and opcrability. ©(2013) by AIChE All rights reserved. Source


Jia S.-L.,China University of Petroleum - East China
Petrochemical Equipment | Year: 2015

Internal in fluid catalytic cracking reaction regenerator by different structure and material composition of the lining, the long-term use, the liner will inevitably appear damaged, blistering and shedding, the repair parts of special parts of the need to adopt special structure in order to prolong the service period. The structure characteristics of lining, for the special parts, such as the lining repair hex steel splicing at the different types of stitching, lining, wall cone are described and equipment connected Y type pipe are introduced. After repair of the lining, its service period exceeded for more than 3 years, the outer wall temperature during normal production equipment could be controlled by standard device, after inspection was made during shutdown, the internal equipment, and repaired parts are basically intact. © 2015, Lanzhou Petroleum Machinery Research Institute. All rights reserved. Source


Gong W.T.,China University of Petroleum - East China
Advanced Materials Research | Year: 2014

Local area network and wide area network are different network protocols, small and medium enterprises due to the geographical distribution of discrete and interface diversity, leading to its needs to be compatible with different network protocols, it is difficult to use a single network protocol to realize network architecture, and due to the ipv4 address scarcity, making its application or maintenance cost greatly increased, based on this, this paper presents the design of multi-protocol network architecture based on point-to-point protocol and frame relay, and with the advantages of the router is compatible with a variety of interfaces and protocols to connect different network interfaces, the paper also gives the configuration of routing information protocol and static routing through local area network, the paper presents the core information of frame relay and point-to-point protocol among the routers, and the paper gives the realization of the network address translation in the end. © (2014) Trans Tech Publications, Switzerland. Source


Bai B.,Missouri University of Science and Technology | Sun Y.,China University of Petroleum - East China | Liu L.,Missouri University of Science and Technology
Shiyou Kantan Yu Kaifa/Petroleum Exploration and Development | Year: 2016

With multiple techniques, the following measurements and analysis were made to characterize the Ordovician Utica shale samples: mineralogy, porosity, microstructure, and surface wettability etc. The test of mercury injection apparatus showed that the pore size of Utica shale is 15-200 nm. X-ray diffraction (XRD) mineralogy analysis and Energy-Dispersive X-ray Spectroscopy (EDS) indicated that in Utica shale non-clay minerals are dominated by calcite and quartz, while clay minerals by illite and chlorite. With the images from scanning electron microscope (SEM), the surface microstructure examination showed various types of pores exist in Utica shale, such as intragranular, intergranular, organic etc. And the pores in organic matter (kerogen) were found in nanometer size (10 to 50 nm). A three-dimensional tomography model and a geometry model of the pores space using FIB-SEM imaging tomography were reconstructed with 250 SEM images. It provides visual insights into the petrophysical properties of Utica shale. Finally, the wettability tests displayed that Utica shale has weak-water wet to intermediate wettability. © 2016, Science Press. All right reserved. Source


Wang Z.-P.,China University of Petroleum - East China
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2012

From the view of vulnerability collaboration and taking high exploration and development oilfield (HEDO) as the research object, which is a typical complex system composed of economy, society, and environment, a vulnerability assessment model was established based on BP neural network and state collaborative function. The model can not only assess the vulnerability of HEDO single subsystem but also assess the vulnerability collaboration of HEDO. The evaluation results by the model agree well with the actual situation of Shengli Oilfield. Source


Wu B.,Nankai University | Zhang H.,China University of Petroleum - East China | Guo P.,Nankai University | Wang Q.,Tianjin Institute of Medical and Pharmaceutical Science | Chang S.,Nankai University
Journal of the Optical Society of America B: Optical Physics | Year: 2010

A multifunctional cross waveguide is designed based on the photonic crystal structure and the liquid crystal material. The different states of the cross waveguide controlled by the electric field make its various functions possible, including a switch with a high extinction ratio, a splitter that divides the terahertz wave into the desired proportions, and a through or 90° turn waveguide. The plane wave expansion method is used to calculate the bandgap in the photonic crystals, and coupling mode theory is adopted to analyze and eliminate the reflection loss. The finite element method is used to get the proper distribution of the external electric field. The properties of the cross waveguide are simulated by the finite difference time domain method, and the results show that the cross waveguide is a multifunctional device with high performance characteristics. © 2010 Optical Society of America. Source


Wei W.,Tianjin University | Lv W.,Tianjin University | Lv W.,Tsinghua University | Wu M.-B.,China University of Petroleum - East China | And 6 more authors.
Carbon | Year: 2013

Graphene wrapping is used to experimentally understand how a carbon coating works in improving the electrochemical performance of the LiFePO4 cathode for a lithium ion battery. A full wrapping of LiFePO4 by graphene is realized by a self-assembly driven by the electrostatic interaction in a graphene oxide suspension. Results indicate that a partial graphene wrapping provides a balance between increased electron transport and fast ion diffusion while full graphene wrapping isolates LiFePO4 from the electrolyte and retards ion diffusion. This indicates that steric hindrance for ion diffusion should be considered together with electron transport in constructing a carbon coating layer. © 2013 Elsevier Ltd. All rights reserved. Source


Gao M.,Shandong University of Science and Technology | Sheng L.,China University of Petroleum - East China
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2011

The stability and stabilization problem for a class of continuous-time Markov jump singular systems is investigated. A sufficient condition is proposed for the Markov jump singular system to be regular, impulse-free and stochastically stable, and the design of the stabilizing controller is presented. Comparing with the previous literature, the system under consideration is more general since their transition probabilities of mode jumps can be partly unknown, and the results are presented in terms of a strict linear matrix inequality. A numerical example shows the effectiveness of the obtained result. Source


Wang J.,Dalian University of Technology | Wang J.,University of Louisville | Wang J.,China University of Petroleum - East China | Wu W.,Dalian University of Technology | Zurada J.M.,University of Louisville
Neurocomputing | Year: 2011

Conjugate gradient methods have many advantages in real numerical experiments, such as fast convergence and low memory requirements. This paper considers a class of conjugate gradient learning methods for backpropagation neural networks with three layers. We propose a new learning algorithm for almost cyclic learning of neural networks based on PRP conjugate gradient method. We then establish the deterministic convergence properties for three different learning modes, i.e., batch mode, cyclic and almost cyclic learning. The two deterministic convergence properties are weak and strong convergence that indicate that the gradient of the error function goes to zero and the weight sequence goes to a fixed point, respectively. It is shown that the deterministic convergence results are based on different learning modes and dependent on different selection strategies of learning rate. Illustrative numerical examples are given to support the theoretical analysis. © 2011 Elsevier B.V. Source


Song J.-K.,China University of Petroleum - East China
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2012

Six influnce factors including population, urbanization rate, per capita GDP, added value proportion of service industry, per GDP energy consumption and coal consumption ratio were seleted as independent variables, and a model based on support vector regression (SVR) was established for predicting carbon emissions of China. Using the data of carbon emissions and influence factors from the year 1980 to 2009 as samples, the SVR model with good learning and generalization ability was established through training and testing. According to the 12th five-year program, prediction values of influence facors under different situations were set, and the carbon emissions of China from the year 2010 to 2015 were predicted. The results show that China can appropriately reduce GDP growth speed and constantly optimize energy structure so as to achieve carbon reduction target efficiently. Source


Guo Y.-H.,China University of Petroleum - East China
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2012

A method to generate a coherent and ultrabroad extreme ultraviolet supercontinuum using Ar+ ions was proposed theoretically. When the medium exposed to a two-color laser field which was synthesized by a few-cycle fundamental laser pulse and its second-harmonics pulse, the harmonics spectrum presents a two-plateau structure. The results show that for the selection of the short quantum path utilizing the two-color scheme, the supercontinuum in the second plateau is almost synchronously emitted and a single 58 attosecond pulse can be directly obtained. By increasing the intensity of the controlling field or adjusting the delay time of the two laser fields, a more intense isolated attosecond pulse is generated. Source


Liu T.-X.,China University of Petroleum - East China | Xu H.-M.,China University of Petroleum - Beijing
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2011

Microscopic pore structure in different types of lithofacies units of fan delta reservoir in the first member of Kongdian group was characterized by photo lithography model and image analysis system in a block of Kongnan area, Dagang Oilfield. The distribution of micro-remaining oil was simulated by constant pressure water injection and pressure-swing water injection. The experimental progresses were recorded and the pictures were taken. The distribution modes of micro-remaining oil in different types of lithofacies units during the waterflood test were analyzed quantitatively and qualitatively, thus the controlling factors for remaining oil distribution were discussed. The results show that the distribution shapes of micro-remaining oil in fan delta reservoir mainly include island remaining oil by blocking in the disconnected pore, accounting for about 75% of all remaining oil, flake remaining oil by interrupting in the small pore and throat, about 20% of all remaining oil, and the beadlike and membranous remaining oil, less than 5% of all remaining oil. The controlling factors for oil displacement efficiency and remaining oil distribution in different types of lithofacies units are mainly pore structure, oil displacement pressure, displacement flow and flow velocity. Pore structure is the fundamental factor influencing oil displacement efficiency under the condition of constant pressure. Oil displacement pressure and oil displacement pattern are the key factors influencing oil displacement efficiency, and increasing pressure and using pressure-swing water injection can increase the oil displacement efficiency by one time. Source


Liu D.,China University of Petroleum - East China | Zhao F.-Y.,TU Munich | Zhao F.-Y.,Hunan University of Technology | Wang H.-Q.,Hunan University of Technology | Rank E.,TU Munich
International Journal of Thermal Sciences | Year: 2013

The backward time modeling of diffusion-convection pollutant dispersions has been developed with quasi-reversibility method in this work. The procedure is applied to the backward time identification of the contaminant release history and source location in a three-dimensional slot ventilated building enclosure. Spatial distributions of pollutant concentrations are known in priori. The effects of supplying air velocity, pollutant source location, pollutant diffusivity property, and pollutant release time on the accuracy of the pollutant dispersion history recovery have been investigated. Numerical results demonstrate that the accuracy of the pollutant dispersion history recovery can be enhanced with different approaches and measures, including the promotion of room ventilation rate, the shrinkage of distance between the pollutant source and supplying air port, and the reduction of pollutant diffusivity. The facilitated implementations of boundary conditions and the improved generality of quasi-reversibility methods make the pollutant source history identifications of less computational efforts. Particularly, the good agreement of the backward time identified source location with the true situation fully shows that quasi-reversibility method is more competitive in the engineering applications involving with convective fluid flows. © 2012 Elsevier Masson SAS. All rights reserved. Source


Wang Z.L.,China University of Petroleum - East China | Tang D.W.,CAS Institute of Engineering Thermophysics
International Journal of Thermal Sciences | Year: 2013

The 3ω principle is presented for the measurement of the heat transfer coefficient (h) based on natural convection model and heat conduction model. The 3ω technique is used at room temperature to measure h over the surfaces of microwires of the diameters 10-100 μm at horizontal and vertical orientations. The fitted results show that the heat loss from the microscale platinum wire to the air is dominated by heat conduction and the natural convection contribution is negligible. The comparison of the measured third harmonics for horizontal and vertical wires justifies that the orientation effect is negligible at microscales. The measured value of h is nearly two orders larger than that at macro scale and of the similar order to those from other literatures. Based on the 3ω principle, an explicit expression with a heat conduction shape factor is introduced and can predict the heat transfer coefficient reasonably in the validated range of frequency. Both the experimental results and the theoretical analysis conclude that the scale effect of heat transfer may be contributed to two factors: the effect of buoyancy, the driving force at microscales may be negligible; the heat loss is enhanced mainly by high ratio of surface to volume at microscales. It also shows the validation of the 3ω principle for thin wire if the heat loss to surrounding gas is dominated by heat conduction at microscale. © 2012 Elsevier Masson SAS. All rights reserved. Source


Liu J.,China University of Petroleum - East China
International Journal of Mechanical Engineering Education | Year: 2013

The course 'Engineering Mechanics' plays an essential role as a bridge and bond between fundamental and specialized knowledge, and it has become a basic class for most engineering students. However, there are many complex concepts and formulas to be covered, and this makes it difficult for students to grasp the spirit of engineering mechanics. One way to solve this problem is to use the analogy study method in learning. Following this new route, students can find the linear quantities and angular quantities in theoretical mechanics, and some analogous relations between stress and deformation for fundamental deformations in mechanics of materials. Through these analogy relations, students can appreciate the essence of different physical phenomena. Indeed, it seems that twice as much is accomplished with half the effort.©Manchester University Press. Source


Yao T.,China University of Petroleum - East China | Huang Y.,CAS Institute of Porous Flow and Fluid Mechanics | Li J.,Geological Scientific Research Institute of Shengli Oilfield Co.
Lixue Xuebao/Chinese Journal of Theoretical and Applied Mechanics | Year: 2012

The research on flow mechanism and productivity evaluation of shale gas is still in its infancy. Based on the complex pore structure of shale gas reservoir, slip flow and adsorption-desorption of shale gas, Darcy model is modified. Compared with the Darcy model in production steady case, the bottom hole pressure based on non-Darcy flow model is higher than that from the Darcy flow; the pressure from the Darcy flow model decays more exaggerated and than predicted well life was shorter. The modified flowing model can describe and characterize shale gas flowing process more accurately. The results can provide basic parameters for the operation and management of the shale gas reservoir. Source


Zhang K.,Beijing University of Technology | Zhang K.,China University of Petroleum - East China | Liu Z.,Beijing University of Technology | Li Y.,Beijing University of Technology | And 3 more authors.
Applied Thermal Engineering | Year: 2014

Absorption heat transformer (AHT) and flash evaporator (FE) are used to reduce the heat consumption of CO2 capture processes and an AHT-FE-aided capture system is proposed. Analyses are carried out to verify the effectiveness in reducing heat consumption. Compared with the base CO 2 capture system of 3000 t/d CO2 capture capacity from a 660MW coal- fired power unit, the AHT-FE-aided capture system reduces the heat consumption from 3.873 GJ/tCO2 to 3.772 GJ/tCO2, and the corresponding energy saving is 2.62%. The economic analysis shows that the annual profit would be 2.94 million RMB Yuan. The payback period of the AHT-FE-aided capture system is approximately 2.4 years. Therefore, the AHT-FE-aided capture system is both economically and technically feasible for improving the CO2 capture energy performance. © 2013 Elsevier Ltd. All rights reserved. Source


Wang Y.,Bavarian Center for Applied Energy Research | Wang Y.,TU Munich | Zhao F.-Y.,Hubei Engineering University | Kuckelkorn J.,Bavarian Center for Applied Energy Research | And 3 more authors.
Energy and Buildings | Year: 2014

Natural ventilation is an effective method to simultaneously improve indoor air quality and reduce energy consumption in buildings, especially when indoor temperature is close to ambient temperature e.g. the transitional seasons in Germany. Heat loss due to opened window and ventilation effectiveness ratio were analytically modeled. Following that, the effects of thermal buoyancy on the steady classroom airflow and thermal stratification comfort as well as the contaminant dispersion were discussed. Classroom displacement ventilation and its thermal stratification as well as indoor air quality indicated by the CO2 concentration have been investigated concerning the effects of supplying air temperature and delivering ventilation flow velocity. Representative thermal comfort parameters, percentage dissatisfied and temperature difference between ankle and head have been evaluated. Subsequent energy consumption efficiency analysis illuminates that classroom energy demands for natural ventilation not only in transitional seasons but also in winter could be decreased with the promotion of the ventilation effectiveness ratio for heat distribution when the natural ventilation rate maintains a constant, and with the shrinking of the ventilation effectiveness ratio for heat distribution when the supplying air temperature is not variable. Detailed fitting correlations of heat loss resulted from opened window and ventilation effectiveness of natural ventilation inside the classroom have been presented. © 2013 Elsevier B.V. Source


Yang R.,Nanjing University | Wang Y.,China University of Petroleum - East China | Cao J.,Nanjing University
Petroleum Science | Year: 2014

The Cretaceous is one of the most important stratigraphic intervals for hydrocarbon source rocks. This article summarizes the distribution, formation, and development characteristics of Cretaceous source rocks and associated oil and gas resources in the world and China, aiming at improving the understanding of this hydrocarbon enrichment and at broadening domestic exploration. Outside China, these rocks are generally formed in marine or transgressive environments during both the Upper and Lower Cretaceous. The majority of Cretaceous source rocks are located in the Persian Gulf, Mediterranean, and Gulf Coast of the USA. Kerogen types within these source rocks have distinct spatial distribution characteristics, with high-latitude Boreal Realm, Tethyan Realm and South Gondwana Realm source rocks containing type III, II, II-III kerogens, respectively. Cretaceous source rocks in China can be mainly divided into four zones: Eastern, Central, Northwest, and Qinghai-Tibet Plateau zones. The majority of Chinese source rocks formed in the Early Cretaceous, whereas the most productive source rocks are developed in the Upper Cretaceous, such as those within the Songliao Basin. Most of these basins are formed in lacustrine environments, although some may have been influenced by transgressive events. Cretaceous source rocks are formed in four distinctive ways: 1) during Oceanic Anoxic Events and associated global sea-level rises, 2) in Black Sea-type retention basins, 3) during transgression and 4) during periods of significant terrestrial input. Formation of these source rocks is controlled by four factors: paleoclimate, paleotopography, transgression, and Oceanic Anoxic Events. These four major controlling factors indicate that China's hydrocarbon exploration within the Cretaceous should focus on two key areas with extremely low exploration levels, the Qinghai-Tibet Plateau and the southeastern coast of China. © 2014 The Authors. Source


Sun B.,Qingdao University | Long Y.-Z.,Qingdao University | Chen Z.-J.,China University of Petroleum - East China | Liu S.-L.,Qingdao University | And 3 more authors.
Journal of Materials Chemistry C | Year: 2014

Due to a variety of outstanding properties, such as large surface area, high length-to-diameter ratio, flexible surface functionality, tunable surface morphologies and superior mechanical performance, electrospun ultrathin fibers are suitable for flexible and stretchable devices, which have aroused much attention nowadays. In this review, we aim to summarize recent developments in the fabrication of flexible/stretchable electronic devices via electrospinning, including strain and pressure sensors, supercapacitors, organic field-effect transistors, and transparent electrodes, which are the key components of flexible/stretchable devices. Moreover, in order to further improve the performance of these devices, some challenges facing electrospun fibers (e.g. production on large scale, precise deposition and flexibility improvement of electrospun inorganic fibers) and subsequent integration for flexible/stretchable electronic devices have also been discussed. © 2014 The Royal Society of Chemistry. Source


Xin Y.,China University of Petroleum - East China
Shiyou Huagong Gaodeng Xuexiao Xuebao/Journal of Petrochemical Universities | Year: 2013

In Zhuangxi Oil Production Station crude stabilization tank as an example, studied the influences of the composition of the oil tank bottom water on oil tank bottom corrosion. Further studies on the mechanism of electrochemical corrosion with the method of polarization curves. Focus on the tank bottom water and various ion on the corrosion rate trend from electrochemical corrosion aspects and effect of ion coordonation. The results show that the stability of Cl-, Ca2+ content in Zhuangxi crude oil station is higher than other oil quality, and the water quality can accelerated the corrosion rate of oil tank in a way. Source


Guo W.,Sinopec | Guo W.,China University of Petroleum - Beijing | Honghai F.,China University of Petroleum - Beijing | Gang L.,China University of Petroleum - East China
Petroleum Exploration and Development | Year: 2011

Bottom hole pressure can be maintained in a reasonable range by using the managed pressure drilling (MPD) technique with special equipment. A calculation model is established for the back pressure and drilling fluid density of constant bottom hole pressure MPD, which are calculated by iterative method. The calculation model is applied to the Well Kela 201. In the comparison of the annulus pressures at 3 314 m in the well, the conventional drilling method cannot provide the appropriate drilling fluid density, but the constant bottom hole pressure MPD technique can make the annulus pressure within the pressure window. The design result of back pressure and mud weight of the narrow pressure window illustrated that the well can drill the target zone at 2 800 m directly by using the MPD technique. It can simplify casing program and save drilling cost. The calculation example demonstrates that this technique not only reduces mud density, but also meets the demand of annulus pressure control. Narrow pressure window can be drilled safely. It provides a technical basis for optimizing well profile. © 2011 Research Institute of Petroleum Exploration & Development, PetroChina. Source


Zhan K.,China University of Petroleum - East China | Hou C.,Harbin Institute of Technology
Optics Express | Year: 2014

We study theoretically surface lattice solitons driven by quadratic electro-optic effect at the interface between an optical lattice and diffusive nonlinear media with self-focusing and self-defocusing saturable nonlinearity. Surface solitons originating from self-focusing nonlinearity can be formed in the semi-infinite gap, and are stable in whole domain of their existence. In the case of self-defocusing nonlinearity, both surface gap and twisted solitons are predicted in first gap. We discover that surface gap solitons can propagate stably in whole existence domain except for an extremely narrow region close to the Bloch band, and twisted solitons are linearly unstable in the entire existence domain. © 2014 Optical Society of America. Source


Zhu L.,China University of Petroleum - East China | Liu X.F.,Missouri University of Science and Technology
IEEE Transactions on Services Computing | Year: 2010

There are at least two challenges with quality management of service-oriented architecture based web service systems: 1) how to link its technical capabilities with customer's needs explicitly to satisfy customers' functional and nonfunctional requirements; and 2) how to determine targets of web service design attributes. Currently, the first issue is not addressed and the second one is dealt with subjectively. Quality Function Deployment (QFD), a quality management system, has found its success in improving quality of complex products although it has not been used for developing web service systems. In this paper, we analyze requirements for web services and their design attributes, and apply the QFD for developing web service systems by linking quality of service requirements to web service design attributes. A new method for technical target setting in QFD, based on an artificial neural network, is also presented. Compared with the conventional methods for technical target setting in QFD, such as benchmarking and the linear regression method, which fail to incorporate nonlinear relationships between design attributes and quality of service requirements, it sets up technical targets consistent with relationships between quality of web service requirements and design attributes, no matter whether they are linear or nonlinear. © 2008 IEEE. Source


Zhao F.-Y.,TU Munich | Zhao F.-Y.,Hunan University of Technology | Rank E.,TU Munich | Liu D.,China University of Petroleum - East China | And 2 more authors.
International Journal of Heat and Mass Transfer | Year: 2012

Combined natural convective heat and moisture transports in a moist-air-filled enclosure with four free vent ports are numerically investigated. Four situations of ambient air states, hot and humid (I), hot and arid (II), cold and arid (III), and cold and humid (IV), are taken into consideration. Convective transports of semi-enclosed air, heat and moisture are respectively analyzed using the contours of streamfunction, heatfunction and massfunction, in addition to the isotherms and iso-concentrations. Overall convective heat transfer rate (Nu) and moisture transfer rate (Sh) of the internal concentrated heat and moisture source have been correlated with the thermal Rayleigh number respectively within the domain of the heat transfer driven flows and that of moisture transfer driven flows. When different initial convective flow conditions were imposed in the cases (I) and (IV), dual steady flow states of semi-enclosed heat and moisture convection are observed, and heat and moisture transport potentials can be enhanced or inhibited depending on the flow solution branches. These results can be adopted to guide the design of natural ventilation in the humid regions. © 2012 Elsevier Ltd. All rights reserved. Source


Xu D.,Harbin Engineering University | Shao H.,China University of Petroleum - East China | Zhang H.,Dalian Maritime University
Neurocomputing | Year: 2012

The momentum method is a commonly used method to accelerate the learning of neural networks. In this paper, a new adaptive momentum algorithm is proposed for split-complex recurrent neural networks training. Different from other momentum methods, this new algorithm uses a variable gain factor and a variable learning rate to speed up the convergence and smooth the weight trace. The global convergence of the new algorithm is proved under mild conditions. Numerical results show that the algorithm is efficient for the given test problems. © 2012 . Source


Zhang M.,Zhangzhou Normal University | Zeng J.,China University of Petroleum - East China
Journal of Chromatographic Science | Year: 2013

This review focuses on a solid-phase microextraction (SPME) method coupled with molecularly imprinted polymers (MIPs), namely molecularly imprinted solid-phase microextraction (MISPME). The first two sections discuss the summaries of conventional SPME and MIPs. The third section reviews the development of MISPME in past years, including the preparation of MISPME, and the applications to compounds in real samples. © [2013] The Author. Source


Liu J.,China University of Petroleum - East China | Lu J.,University of Manchester | Cui Z.,University of Oxford
Bioprocess and Biosystems Engineering | Year: 2011

The optimization of operating conditions for cellulose hydrolysis was systemically undertaken using an ultra-scaled down membrane bioreactor based on the parameter scanning ultrafiltration apparatus. The bioconversion of cellulose saccharification was carried out with freely suspended cellulase from Aspergillus niger as the biocatalyst. The polyethersulfone ultrafiltration membranes with a molecular weight cutoff of 10 kDa were used to construct the enzymatic membrane bioreactor, with the membrane showing a complete retaining of cellulase and cellobiase. The influence of solution pH, temperature, salt (NaCl) concentration, presence of cellobiase, cellulose-to-enzyme ratio and stirring speed on reducing sugar production was examined. The results showed that the addition of an appropriate amount of NaCl or cellobiase had a positive effect on reducing sugar formation. Under the identified optimal conditions, cellulose hydrolysis in the enzymatic membrane bioreactor was tested for a long period of time up to 75 h, and both enzymes and operation conditions demonstrated good stability. Also, the activation energy (E a) of the enzymatic hydrolysis, with a value of 34.11 ± 1.03 kJ mol-1, was estimated in this study. The operational and physicochemical conditions identified can help guide the design and operation of enzymatic membrane bioreactors at the industrial scale for cellulose hydrolysis. © 2010 Springer-Verlag. Source


Zhou J.,Shandong University of Technology | Li Z.,Shandong University of Technology | Xing W.,China University of Petroleum - East China | Zhu T.,Shandong University of Technology | And 2 more authors.
Chemical Communications | Year: 2015

N-doped microporous carbons with uniform ultramicropores (∼0.50 nm) are facilely prepared by direct carbonization of K+ exchanged meta-aminophenol-formaldehyde resin. These materials give an unprecedented CO2 uptake of 1.67 mmol g-1 at 25 °C and 0.15 bar and superior CO2-over-N2 selectivity (50:1). This journal is © The Royal Society of Chemistry 2015. Source


Zhao H.,China University of Petroleum - East China | Li Y.,Sinopec | Cao L.,Sinopec
Shiyou Kantan Yu Kaifa/Petroleum Exploration and Development | Year: 2010

On the basis of the dynamic features of polymer flooding water-cut variation curve and a couple of major establishment principles, a novel quantitative characterization model for polymer flooding water-cut variation was built. The model mainly includes four characteristic parameters with specific meanings, namely the polymer pore volume injected at the initial time of water-cut decrement, the corresponding polymer pore volume injected at maximum water-cut decrement, the polymer pore volume injected when water-cut recovering to the initial water-cut, and the maximum water-cut decrement. The automatic regression method for specific parameters of the model was proposed on the particle swarm optimization algorithm. Based on reservoir numerical simulation, in combination with orthogonal experimental design and support vector machine approach, the prediction model of characteristic parameters was presented which can fairly consider the influence of the combination of multi-factors. The practical application results indicated that the water-cut variation and performance trend can be easily determined for the scheme compilation and adjustment of polymer flooding by using the proposed method. Source


Zhang P.,China University of Petroleum - East China
PLoS ONE | Year: 2015

The evolution and development of the three-dimensional (3D) architectural landscape is the basis of proper urban planning, eco-environment construction and the improvement of environmental quality. This paper presents the spatiotemporal characteristics of the 3D architectural landscape of the Shinan and Shibei districts in Qingdao, China, based on buildings' 3D information extracted from Quickbird images from 2003 to 2012, supported by Barista, landscape metrics and GIS. The results demonstrated that: (1) Shinan and Shibei districts expanded vertically and urban land use intensity increased noticeably from year to year. (2) Significant differences in the 3D architectural landscape existed among the western, central and eastern regions, and among the 26 sub-districts over the study period. The differentiation was consistent with the diverse development history, function and planning of the two districts. Finally, we found that population correlates positively with the variation in the 3D architectural landscape. This research provides an important reference for related studies, urban planning and eco-city construction. © 2015 Peifeng Zhang. Source


Shi L.,Shandong University | Zhao M.,China University of Petroleum - East China | Zheng L.,Shandong University
RSC Advances | Year: 2012

The phase behavior of ternary systems involving long-chain pyrrolidinium ionic liquids, N-alkyl-N-methylpyrrolidinium bromide (C nMPB, n = 12, 14, 16), water, and 1-decanol was investigated at 25°C. Polarized optical microscopy (POM), small-angle X-ray scattering (SAXS), and rheological measurements were employed to investigate the lyotropic liquid crystalline (LC) phases. Lamellar phase (L α) and hexagonal phase (H 1) were found to exist in all the three systems, but the isotropic cubic phase only appears in the C 12MPB and C 14MPB systems. Greater surfactant content leads to a denser aggregation of the cylindrical units in the H 1 phase, and the structural parameters of L α phase depends on water content. The alkyl chain length of C nMPB also has interesting effect on the structural parameters and rheological properties of the LC phase. Compared with a similar ternary system of 1-hexadecyl-3- methylimidazolium chloride ([C 16mim]Cl) and traditional cationic surfactants cetyltrimethylammonium bromide (C 16TAB), the effect of the cationic group on the phase behavior was also investigated. © The Royal Society of Chemistry 2012. Source


Li C.P.,Shanghai University | Zhang F.R.,Shanghai University | Zhang F.R.,China University of Petroleum - East China
European Physical Journal: Special Topics | Year: 2011

Recently, fractional calculus has attracted much attention since it plays an important role in many fields of science and engineering. Especially, the study on stability of fractional differential equations appears to be very important. In this paper, a brief overview on the recent stability results of fractional differential equations and the analytical methods used are provided. These equations include linear fractional differential equations, nonlinear fractional differential equations, fractional differential equations with time-delay. Some conclusions for stability are similar to that of classical integer-order differential equations. However, not all of the stability conditions are parallel to the corresponding classical integer-order differential equations because of non-locality and weak singularities of fractional calculus. Some results and remarks are also included. © 2011 EDP Sciences and Springer. Source


Liu W.,China University of Petroleum - East China | Tao D.,Intelligent Systems Technology, Inc. | Cheng J.,CAS Shenzhen Institutes of Advanced Technology | Cheng J.,Chinese University of Hong Kong | Tang Y.,Macau University of Science and Technology
Computer Vision and Image Understanding | Year: 2014

Sparse coding represents a signal sparsely by using an overcomplete dictionary, and obtains promising performance in practical computer vision applications, especially for signal restoration tasks such as image denoising and image inpainting. In recent years, many discriminative sparse coding algorithms have been developed for classification problems, but they cannot naturally handle visual data represented by multiview features. In addition, existing sparse coding algorithms use graph Laplacian to model the local geometry of the data distribution. It has been identified that Laplacian regularization biases the solution towards a constant function which possibly leads to poor extrapolating power. In this paper, we present multiview Hessian discriminative sparse coding (mHDSC) which seamlessly integrates Hessian regularization with discriminative sparse coding for multiview learning problems. In particular, mHDSC exploits Hessian regularization to steer the solution which varies smoothly along geodesics in the manifold, and treats the label information as an additional view of feature for incorporating the discriminative power for image annotation. We conduct extensive experiments on PASCAL VOC'07 dataset and demonstrate the effectiveness of mHDSC for image annotation. © 2013 Elsevier Inc. All rights reserved. Source


Li J.,Shandong University | Xue Y.,China University of Petroleum - East China | Xu B.,Shandong University of Technology | Gao H.,Shandong University
Dianwang Jishu/Power System Technology | Year: 2013

Complicated structure and heavy calculation burden are defects of existing distributed parameter model and multiple lumped parameter models utilized for the analysis on high-frequency transient characteristics of transmission lines. The structure of single link models with lumped parameters is simple, however its applicable frequency band is far below the first resonant frequency band of distributed parameter model. For this reason, based on the cases of open-circuit and short-circuit at the end of single-phase uniform transmission line, impedance characteristics of the model with distributed parameters, the single-link Π-shaped, T-shaped and Γ-shaped models with lumped parameters are analyzed, and according to the result of error analysis on equivalent impedance at the lowest frequency band of each model a method of parameter calculation for single link model with lumped parameters is proposed, namely based on the principle of ensuring power-frequency equivalent impedances equal, the first resonant frequency bands equal and comprehensive error of equivalent reactance within the lowest frequency band minimum, the applicable frequency band of single-link Π-shaped, T-shaped and Γ-shaped models is raised to the first resonant frequency band of distributed parameter model, thus the applicable range of Π-shaped, T-shaped and Γ-shaped models are extended. Simulation results show that the proposed method is effective and correct. Source


Zhi H.-Y.,China University of Petroleum - East China
Communications in Theoretical Physics | Year: 2013

In this paper, some new formal similarity reduction solutions for the (2+1)-dimensional Nizhnik-Novikov-Veselov equation are derived. Firstly, we derive the similarity reduction of the NNV equation with the optimal system of the admitted one-dimensional subalgebras. Secondly, by analyzing the reduced equation, three types of similarity solutions are derived, such as multi-soliton like solutions, variable separations solutions, and KdV type solutions. © 2013 Chinese Physical Society and IOP Publishing Ltd. Source


Zhang H.-G.,Northeastern University China | Zhang X.,China University of Petroleum - East China | Luo Y.-H.,Northeastern University China | Yang J.,Northeastern University China
Zidonghua Xuebao/Acta Automatica Sinica | Year: 2013

Adaptive dynamic programming (ADP) is a novel approximate optimal control scheme, which has recently become a hot topic in the field of optimal control. As a standard approach in the field of ADP, a function approximation structure is used to approximate the solution of Hamilton-Jacobi-Bellman (HJB) equation. The approximate optimal control policy is obtained by using the offine iteration algorithm or the online update algorithm. This paper gives a review of ADP in the order of the variation on the structure of ADP scheme, the development of ADP algorithms and applications of ADP scheme, aiming to bring the reader into this novel field of optimization technology. Furthermore, the future studies are pointed out. Copyright © 2013 Acta Automatica Sinica. Source


Xie X.,Tianjin University of Technology | Zhang C.,Tianjin University of Technology | Wu M.-B.,China University of Petroleum - East China | Tao Y.,Tianjin University of Technology | And 4 more authors.
Chemical Communications | Year: 2013

Graphene oxide hydrogel is used as a reactive template to prepare nanoporous materials with a 3D microstructure. The as-prepared porous MnO 2 shows a capacitance retention of ∼70.6% at a current density as high as 15 A g-1, resulting from the 3D interconnected ion transport channel replicated from the graphene oxide hydrogel. © 2013 The Royal Society of Chemistry. Source


Qu X.,China University of Petroleum - East China
World Transactions on Engineering and Technology Education | Year: 2015

Differences in the curriculum design and training at different universities were found as a result of a comparative study carried out on six well-known Chinese universities at which geology undergraduate courses are taught. On the basis of the comparative analysis of the training plans, an undergraduate training model for geology courses is proposed. Further, the advantages and disadvantages of undergraduate training in geology at petroleum institutions are presented and discussed in this article. © 2015 WIETE. Source


Bao X.-X.,China University of Petroleum - East China
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2014

A modal identification scheme based on signals denoised under ambient excitation was proposed here. With this method the natural excitation technique (NExT) was firstly applied to get the cross-correlation function for the measured random responses, and then the structured low rank approximation (SLRA) method was implemented to achieve the signals denoised. Finally, the modal parameters were estimated by using the complex exponential method (Prony's method) from the noise-reduced signals. The effectiveness of the proposed method was verified by using numerical simulation and model tests. ©, 2014, Chinese Vibration Engineering Society. All right reserved. Source


Yang C.,CAS Wuhan Institute of Rock and Soil Mechanics | Jing W.,CAS Wuhan Institute of Rock and Soil Mechanics | Jing W.,China University of Petroleum - East China | Daemen J.J.K.,University of Nevada, Reno | And 2 more authors.
Reliability Engineering and System Safety | Year: 2013

Salt rock is internationally accepted as an ideal medium for energy storage. As an energy storage structure, the safety of hydrocarbon storage caverns in salt rock is related to the national economy and to social public security. Risk analysis is an important method of engineering safety evaluation. In this paper the major risks associated with hydrocarbon storage caverns in bedded salt rock are defined. The major risks are classified under the headings of 'oil and gas leakage', 'ground subsidence', and 'cavern failure', and are discussed under these topical titles. The factors leading to the major risks associated with storage caverns are identified by reviewing descriptions of major accidents of salt storage caverns around the world. Fault tree models for the three major risks are established and analyzed. Basic paths of the risk and their occurrence probability ranking are derived. The risk factors which contribute greatly to the risk are identified by calculating the importance degree of all the basic events. Finally, a comprehensive evaluation methodology for major risk loss is generated based on the analytic hierarchy process. This provides a theoretical foundation for the evaluation and prevention of major risks in the construction and operation of storage caverns in bedded salt rock. © 2013 Elsevier Ltd. All rights reserved. Source


Chen D.-M.,Nanyang Technological University | Chen D.-M.,China University of Petroleum - East China | Shenai P.M.,Nanyang Technological University | Zhao Y.,Nanyang Technological University
Physical Chemistry Chemical Physics | Year: 2011

Opening up a band gap in graphene holds a crucial significance in the realization of graphene-based electronics. Doping with organic molecules to alter the electronic properties of graphene is perceived as an effective band gap engineering approach. Using the tight binding model, we examined the band gap opening of monolayer graphene due to the adsorption of pyrene molecules on both of its sides. It was found that the breakdown of the sublattice symmetry in pyrene-dispersed graphene leads to a band gap of ∼10 meV. © 2011 the Owner Societies. Source


Wang Y.,HIGH-TECH | Li M.,China University of Petroleum - East China
Journal of Chinese Mass Spectrometry Society | Year: 2015

The EI mass spectra of two kinds of fluoro-p-terphenyl liquid crystalline compounds (FTPLCCs) were analyzed by gas chromatogram-mass spectrometry (GC/MS), and the fragmentation rules of FTPLCCs were summarized. The main fragmentation pathways of FTPLCCs are the loss of an alkyl from the molecular ions via benzyl cleavage. The fragmental ion at m/z 274 can be produced from some other bigger fragmental ions, which is contrary to the even electron rule. The position of fluorine atom has some influence on the fragmentation pathways of FTPLCCs. The relative abundances of the fragmental ions have obvious differences caused by the electron-withdrawing inductive effect of fluorine atom and resulting alternation of the conjugation degree of the terphenyl moieties. ©, 2015, Chinese Society for Mass Spectrometry. All right reserved. Source


Li S.-R.,China University of Petroleum - East China
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2013

A numerical method for solving nonlinear optimal control problems including terminal state constraints, state and control inequality constraints was proposed. The method is based on triangular orthogonal functions. By approximating the dynamic systems, performance index and boundary conditions into triangular orthogonal series, the optimal control problem is converted into algebraic equations with unknown coefficients. The results of illustrative examples demonstrate the accuracy and applicability of the proposed method. Source


Ling C.,China University of Petroleum - East China
Proceedings - 2012 International Symposium on Instrumentation and Measurement, Sensor Network and Automation, IMSNA 2012 | Year: 2012

Means of communication commonly used in industry are compared in this paper. Communication structure based on GPRS and CDMA is established. And communication protocols of GPRS and CDMA-based products are selected. This paper aims to simulate the data communication structure and compile the communication program. Application of wireless data services in rainfall gathering system, which is based on GPRS/CDMA wireless communication technology, is introduced in this paper. © 2012 IEEE. Source


Zuo W.,China University of Petroleum - East China | Song Y.,Tongji University
Journal of Mathematical Analysis and Applications | Year: 2015

The spatio-temporal patterns of a general reaction-diffusion equation with non-local delay are considered. By analyzing the characteristic equations and applying the complex plane theory, the stability of the constant steady state and the possible Hopf bifurcations are obtained with the mean delay as a bifurcation parameter. The absolute stable, conditional stable and unstable region can be explicitly divided by the coefficients of the term without delay and the term with non-local delay. By investigating the effect of any weight function on the dynamics of the system, we establish the existence of spatially homogeneous and inhomogeneous bifurcating periodic solutions. And the algorithm for determining the direction and stability of Hopf bifurcation is derived by computing the normal form on the center manifold. The result shows that, for the case of strong kernel, the average delay may induce the stability switches. Finally, the theoretical results are applied to a diffusive food-limited population model. Numerical simulations show the existence of the orbit connecting the unstable spatially inhomogeneous periodic solutions to stable spatially homogeneous periodic solutions. © 2015 Elsevier Inc. Source


Wang C.,China University of Petroleum - East China | Wang C.,University of Leipzig | Morgner H.,University of Leipzig
Physical Chemistry Chemical Physics | Year: 2011

We have determined the surface excess of surface active anion and counter-ions in a non-aqueous polar solution of anionic surfactants blends, as well as their distributions near the solution surface. The blends of two anionic surfactants, sodium dodecyl sulfate (SDS) and cesium dodecyl sulfate (CDS), with different contents were used as solutes to prepare the solutions. According to the isotherms that are separately fitted to the pure SDS and the pure CDS solutions (C. Wang and H. Morgner, Langmuir, 2010, 26, 3121), CDS has a slightly but significantly higher surface excess than SDS (CDS is 14.8% higher) at the concentration of 0.04 molal kg-1 solvent. Therefore, in this work we chose 0.04 molal kg-1 solvent as total anion concentration and varied the contents of surfactants. From present experimental results, we found that the surface excess of anion increases slightly with the CDS in the bulk content. Importantly, the fractions of Cs+ in cationic surface excess are higher than its contents in the bulk for all three solutions. This demonstrates that Cs+ is more competitive than Na+ in the adsorption. The surface structure of the solutions have been characterized by concentration-depth profiles, of Cs+, Na+ and of sulfur which is used to identify dodecyl sulfate. Those profiles evidence that Cs ions penetrate deeper than sodium ions into the layer formed by the heads of the anions, reducing the electrical potential of the surface more efficiently. This can be used to explain the adsorption competition between those two counter-ions. The cause that makes Cs+ more competitive than Na + in the adsorption can be attributed to its less tightly bound solvation shell, and thus, to its effectively smaller ion size. © the Owner Societies 2011. Source


Wang C.,China University of Petroleum - East China
Journal of Dispersion Science and Technology | Year: 2014

We have separately determined the surface tension of pure aqueous solutions of cetyltrimethylammonium chloride and cetyltrimethylammonium bromide and their surface potentials by a Kelvin probe system. With the help of Gibbs equation, the surface excess has been determined through approximating the chemical activity of the surfactant by their dilute bulk concentration. In the following, the surface potential-surface excess isotherms were established. Those potential isotherms evidence that cetyltrimethylammonium chloride solution has a higher value compared to that of cetyltrimethylammonium bromide under equal surface excess. This phenomenon is supposed to be owed to the different distributions of chloride and bromide ions within the adsorption layer of the solutions, which can be attributed to the different properties of those two anions. © 2014 Copyright Taylor & Francis Group, LLC. Source


Zhan K.,Harbin Institute of Technology | Zhan K.,China University of Petroleum - East China | Hou C.,Harbin Institute of Technology | Tian H.,Harbin Institute of Technology
Applied Physics B: Lasers and Optics | Year: 2010

We provide a theoretical investigation of effects of the temperature on the steady-state bright solitons in centrosymmetric photorefractive crystals. Three physical factors related to the effects of the temperature, i.e., the dielectric constant, diffusion process and dark irradiance, are considered. Our results show that both the intensity profile and self-deflection of solitons strongly depend on the crystal temperature and the dielectric constant temperature dependence dominates the process. © Springer-Verlag 2010. Source


Li A.,China University of Petroleum - East China | Liu P.,Beihang University
Journal of Hydraulic Research | Year: 2010

Scour of rock bed downstream of high dams ismainly caused by the transient forces as a result of the propagation of fluctuating pressures, which is significantly controlled by the rock fracture-structure. The physical mechanism of rock disintegration and scour pool forming are analysed herein by considering the fracture- structure of rock bed. A two-dimensional discrete fracture network is imitated applying the Monte-Carlo method. The model of transient flow is established along with each discrete fracture to simulate numerically the propagation of fluctuating pressure waves. Applying the method of automatic tracing of rock blocks layer by layer, the mechanism of disorganization of fractured rock, both the transient physical and dynamic characteristics of isolated rocks, and the damage process of the rock bed are discussed. Finally, a stability criterion of rock blocks and the evaluationmethod of equilibrium scour depth are established. © 2010 International Association for Hydro-Environment Engineering and Research. Source


Wang P.-X.,China University of Petroleum - East China | Zhang J.,Sinopec
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2012

In order to improve the accuracy, speed and stability of multi-parameters automatic matching for fractured horizontal well test analysis, a new parallel group particle swarm optimization algorithm combined with traditional method, intelligence algorithm and parallel algorithm was proposed. The proposed algorithm was combined with Gauss-Newton algorithm and solved by OpenMP parallel algorithm. The results show that in the particle swarm optimization algorithm, the searching direction of particle approaches to linear by clustering particles. The shortcoming of the local optimization is avoided and searching speed is increased. The algorithm combines Gauss-Newton algorithm with particle swarm optimization, which ensures its stability. Meanwhile, OpenMP parallel optimization algorithm can reduce the complexity of the model and improve the calculation efficiency. Compared with other optimization calculation algorithms, the algorithm shows high accuracy, high efficiency and the capability of dividing flow stage to some extent in well test interpretation for multi-fractures horizontal well. Source


Lu B.,China University of Petroleum - East China | Fan W.,Virginia Polytechnic Institute and State University | Zhou M.,Virginia Polytechnic Institute and State University
Computers in Human Behavior | Year: 2016

Lacking the presence of human and social elements is claimed one major weakness that is hindering the growth of e-commerce. The emergence of social commerce might help ameliorate this situation. Social commerce is a new evolution of e-commerce that combines the commercial and social activities by deploying social technologies into e-commerce sites. Social commerce reintroduces the social aspect of shopping to e-commerce, increasing the degree of social presences in online environment. Drawing upon the social presence theory, this study theorizes the nature of social aspect in online SC marketplace by proposing a set of three social presence variables. These variables are then hypothesized to have positive impacts on trusting beliefs which in turn result in online purchase behaviors. The research model is examined via data collected from a typical e-commerce site in China. Our findings suggest that social presence factors grounded in social technologies contribute significantly to the building of the trustworthy online exchanging relationships. In doing so, this paper confirms the positive role of social aspect in shaping online purchase behaviors, providing a theoretical evidence for the fusion of social and commercial activities. Finally, this paper introduces a new perspective of e-commerce and calls more attention to this new phenomenon of social commerce. © 2015 Elsevier Ltd. All rights reserved. Source


Wang F.,Harbin Institute of Technology | Tan J.,Harbin Institute of Technology | Shuai Y.,Harbin Institute of Technology | Gong L.,China University of Petroleum - East China | Tan H.,Harbin Institute of Technology
Energy Conversion and Management | Year: 2014

The calorific value of syngas can be greatly upgraded during the methane steam reforming process by using concentrated solar energy as heat source. In this study, the Monte Carlo Ray Tracing (MCRT) and Finite Volume Method (FVM) coupling method is developed to investigate the hydrogen production performance via methane steam reforming in porous media solar thermochemical reactor which includes the mass, momentum, energy and irradiative transfer equations as well as chemical reaction kinetics. The local thermal non-equilibrium (LTNE) model is used to provide more temperature information. The modified P1 approximation is adopted for solving the irradiative heat transfer equation. The MCRT method is used to calculate the sunlight concentration and transmission problems. The fluid phase energy equation and transport equations are solved by Fluent software. The solid phase energy equation, irradiative transfer equation and chemical reaction kinetics are programmed by user defined functions (UDFs). The numerical results indicate that concentrated solar irradiation on the fluid entrance surface of solar chemical reactor is highly uneven, and temperature distribution has significant influence on hydrogen production. © 2014 Elsevier Ltd. All rights reserved. Source


"Oil Geophysical Prospecting" has widely influence in the petroleum geophysical prospecting field in China as its articles are included in the literature database by famous retrieval mechanisms such as American EI. In 2012, "Oil Geophysical Prospecting" totally published 175 articles. The article contents can be roughly summarized as 8 aspects: seismic forward modeling, seismic data acquisition, seismic data processing, seismic integrated interpretation, gravity, magnetic, electrical and electromagnetic methods, borehole logging, seismic and geology research, and reviews and forums. With highly professional views, these articles published in "Oil Geophysical Prospecting" not only report new methods, new technologies, new developments and innovation achievements, but also show R&D performance and application capabilities in the petroleum geophysical prospecting field in China. Some suggestions are given in this paper. Source


Liu Y.,Jilin University | Yin X.,Jilin University | Zhang J.,Jilin University | Yu S.,China University of Petroleum - East China | And 2 more authors.
Electrochimica Acta | Year: 2014

Super-hydrophobic surface has many special functions that are studied wildly. The ingenious microstructures of typical plant leaves with super-hydrophobicity enlighten researchers to design and fabricate artificial super-hydrophobic surface. Being the lightest alloy among structural metals materials magnesium alloy was restricted due to its poor corrosion resistance. A super-hydrophobic surface with self-cleaning was successfully deposited on AZ91D magnesium alloy by the nickel plating process. The super-hydrophobic surfaces were covered with cauliflower-like cluster binary micro-nano structural Ni coatings. The procedure was that the samples were processed by plating after pretreatment, finally modified by stearic acid (CH3(CH 2)16COOH). The surface morphologies, chemical composition, wettability and corrosion resistance are characterized by means of SEM, FT-IR, water contact angle and electrochemical impedance spectroscopy (EIS) measurements. The as-prepared super-hydrophobic surface has a contact angle as high as 160.8 ± 1 and a SA as low as 1.8 ± 1, showing good long-term stability. The super-hydrophobic surface exhibited excellent corrosion resistance property in the 3.5 wt. % NaCl solution. This method could provide a straightforward and effective route to fabricate large-area super-hydrophobic surface with anticorrosion and self-cleaning for a great number of potential applications, and easily extended to other metal materials. © 2014 Elsevier Ltd. Source


Ali M.M.,University of California at Irvine | Li F.,University of California at Irvine | Li F.,University of Alberta | Zhang Z.,University of California at Irvine | And 7 more authors.
Chemical Society Reviews | Year: 2014

Rolling circle amplification (RCA) is an isothermal enzymatic process where a short DNA or RNA primer is amplified to form a long single stranded DNA or RNA using a circular DNA template and special DNA or RNA polymerases. The RCA product is a concatemer containing tens to hundreds of tandem repeats that are complementary to the circular template. The power, simplicity, and versatility of the DNA amplification technique have made it an attractive tool for biomedical research and nanobiotechnology. Traditionally, RCA has been used to develop sensitive diagnostic methods for a variety of targets including nucleic acids (DNA, RNA), small molecules, proteins, and cells. RCA has also attracted significant attention in the field of nanotechnology and nanobiotechnology. The RCA-produced long, single-stranded DNA with repeating units has been used as template for the periodic assembly of nanospecies. Moreover, since RCA products can be tailor-designed by manipulating the circular template, RCA has been employed to generate complex DNA nanostructures such as DNA origami, nanotubes, nanoribbons and DNA based metamaterials. These functional RCA based nanotechnologies have been utilized for biodetection, drug delivery, designing bioelectronic circuits and bioseparation. In this review, we introduce the fundamental engineering principles used to design RCA nanotechnologies, discuss recently developed RCA-based diagnostics and bioanalytical tools, and summarize the use of RCA to construct multivalent molecular scaffolds and nanostructures for applications in biology, diagnostics and therapeutics. © 2014 the Partner Organisations. Source


Li Y.,China University of Petroleum - East China
Advanced Materials Research | Year: 2013

Signal sparse representation in signal processing has many important applications, but the calculation amount of sparse decomposition is difficult to spread to realize industrialization because of its enormous calculation amount. At present, most of us make efforts to shorten the time of sparse decomposition calculation and improve the algorithm in order to make sparse decomposition feasible in its actual application. Although we make great achievements, the time cost by these improved algorithms is still difficult to be accepted. With the rapid development of internet in recent years, cloud computing and grid computing improve the computational ability so greatly that it can make a large amount of data calculation possible in reality. We introduce the grid computing into the sparse calculation so as to make its applicability possible in the practice. The thesis is to build a grid frame work. The performance of sparse decomposition is greatly improved by its calculating allocation to each node of grid computing, which makes it possible in its practical application. © (2013) Trans Tech Publications, Switzerland. Source


Li C.M.,China University of Petroleum - East China
Key Engineering Materials | Year: 2010

Taking the mechanics characteristic of electromotor, the mass of slide and the sliding friction into account, the resolving calculating formulae for the kinematics and dynamic analysis of bull-nose plane six-rod mechanism is educed based on the dynamics principle. The disposing method of friction force operation direction is proposed. The computing simulation of this mechanism shows that the speed fluctuation would be aggrandized with the friction considered and the periodic change of friction force direction would be presented in the periodic change of acceleration. At last, the adding flexible component for the computing simulation near to actual movement is pointed out. © (2010) Trans Tech Publications. Source


Li Y.,China University of Petroleum - East China
Nonlinear Dynamics | Year: 2016

This paper is devoted to consider a time-delayed diffusive prey–predator model with hyperbolic mortality. We focus on the impact of time delay on the stability of positive constant solution of delayed differential equations and positive constant equilibrium of delayed diffusive differential equations, respectively, and we investigate the similarities and differences between them. Our conclusions show that when time delay continues to increase and crosses through some critical values, a family of homogenous and inhomogeneous periodic solutions emerge. Particularly, we find the minimum value of time delay, which is often hard to be found. We also consider the nonexistence and existence of steady state solutions to the reaction–diffusion model without time delay. © 2016 Springer Science+Business Media Dordrecht Source


Zhao X.,Bohai University | Zhao X.,China University of Petroleum - East China | Zhang L.,Harbin Institute of Technology | Shi P.,University of South Wales | And 2 more authors.
IEEE Transactions on Fuzzy Systems | Year: 2014

In this paper, novel stability conditions for Takagi-Sugeno (T-S) fuzzy systems are presented. The so-called nonquadratic membership-dependent Lyapunov function is first proposed, which is formulated in a higher order form of both the system states and the normalized membership functions than existing techniques in the literature. Then, new membership-dependent stability conditions are developed by the new Lyapunov function approach. It is shown that the conservativeness of the obtained criteria can be further reduced as the degree of the Lyapunov function increases. Two numerical examples are given to demonstrate the effectiveness and less conservativeness of the obtained theoretical results. © 1993-2012 IEEE. Source


Hu S.-L.J.,University of Rhode Island | Bao X.,China University of Petroleum - East China | Li H.,Ocean University of China
Science China: Physics, Mechanics and Astronomy | Year: 2012

Modal identification involves estimating the modal parameters, such as modal frequencies, damping ratios, and mode shapes, of a structural system from measured data. Under the condition that noisy impulse response signals associated with multiple input and output locations have been measured, the primary objective of this study is to apply the local or global noise removal technique for improving the modal identification based on the polyreference time domain (PTD) method. While the traditional PTD method improves modal parameter estimation by over-specifying the computational model order to absorb noise, this paper proposes an approach using the actual system order as the computational model order and rejecting much noise prior to performing modal parameter estimation algorithms. Two noise removal approaches are investigated: a "local" approach which removes noise from one signal at a time, and a "global" approach which removes the noise of multiple measured signals simultaneously. The numerical investigation in this article is based on experimental measurements from two test setups: a cantilever beam with 3 inputs and 10 outputs, and a hanged plate with 4 inputs and 32 outputs. This paper demonstrates that the proposed noise-rejection method outperforms the traditional noise-absorption PTD method in several crucial aspects. © Science China Press and Springer-Verlag Berlin Heidelberg 2012. Source


Ma M.,China University of Petroleum - East China | Trzesniewski B.J.,Technical University of Delft | Xie J.,TU Eindhoven | Smith W.A.,Technical University of Delft
Angewandte Chemie - International Edition | Year: 2016

In this work, the selective electrocatalytic reduction of carbon dioxide to carbon monoxide on oxide-derived silver electrocatalysts is presented. By a simple synthesis technique, the overall high faradaic efficiency for CO production on the oxide-derived Ag was shifted by more than 400mV towards a lower overpotential compared to that of untreated Ag. Notably, the Ag resulting from Ag oxide is capable of electrochemically reducing CO2 to CO with approximately 80% catalytic selectivity at a moderate overpotential of 0.49V, which is much higher than that (ca. 4%) of untreated Ag under identical conditions. Electrokinetic studies show that the improved catalytic activity is ascribed to the enhanced stabilization of COOH. intermediate. Furthermore, highly nanostructured Ag is likely able to create a high local pH near the catalyst surface, which may also facilitate the catalytic activity for the reduction of CO2 with suppressed H2 evolution. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Sun J.B.,China University of Petroleum - East China | Zhang G.A.,Hubei Key Laboratory Of Materials Chemistry And Service Failure | Liu W.,University of Science and Technology Beijing | Lu M.X.,University of Science and Technology Beijing
Corrosion Science | Year: 2012

The formation mechanism of corrosion scale and electrochemical characteristic of low alloy steel in CO 2-saturated solution were investigated by electrochemical measurements and surface characterization. The results show that the electrochemical behavior is associated with the formation of corrosion scale and the microstructure of steel. At the initial polarization stage, ferrite dissolves preferentially and leaves Fe 3C behind, which results in high Fe 2+ ions concentration between lamellar Fe 3C. This situation facilitates the formation of FeCO 3 scale between the lamellar Fe 3C. With further increase of polarization times, the whole electrode surface is covered by FeCO 3 scale. © 2011. Source


Huang X.-G.,China University of Petroleum - East China | Xu J.-Q.,Shanghai JiaoTong University
Journal of Zhejiang University: Science A | Year: 2013

This paper presents a deterministic model to predict the pit evolving morphology and crack initiation life of corrosion fatigue. Based on the semi-ellipsoidal pit assumption, the thermodynamic potential including elastic energy, surface energy and electrochemical energy of the cyclically stressed solid with an evolving pit is established, from which specific parameters that control the pit evolution are introduced and their influence on the pit evolution are evaluated. The critical pit size for crack nucleation is obtained from stress intensity factor criterion and the crack nucleation life is evaluated by Faraday's law. Meanwhile, this paper presents a numerical example to verify the proposed model and investigate the influence of cyclic load on the corrosion fatigue crack nucleation life. The corrosion pit appears approximately as a hemisphere in its early formation, and it gradually transits from semicircle to ellipsoid. The strain energy accelerates the morphology evolution of the pit, while the surface energy decelerates it. The higher the stress amplitude is, the smaller the critical pit size is and the shorter the crack initiation life is. © 2013 Zhejiang University and Springer-Verlag Berlin Heidelberg. Source


Zhan K.,Harbin Institute of Technology | Zhan K.,China University of Petroleum - East China | Hou C.,Harbin Institute of Technology | Du Y.,Harbin Institute of Technology
Optics Communications | Year: 2010

The effects of diffusion on self-deflection of steady-state bright spatial solitons in biased centrosymmetric photorefractive crystals are investigated systematically by both numerical and perturbation methods. The results show that the soliton propagates along a parabolic trajectory and the central spatial frequency component shifts linearly with the propagation distance. Both the deflection effects vary cubically with applied external bias field. © 2009 Elsevier B.V. All rights reserved. Source


Yu S.R.,China University of Petroleum - East China | Yu S.R.,Hubei University | Liu J.A.,Jilin University | Diao W.,Jilin University | And 2 more authors.
Journal of Alloys and Compounds | Year: 2014

A superhydrophobic surface with the bionic microtexture was prepared successfully on X52 pipeline steel using the sandblasting roughening treatment, chemical etching and fluorination treatment composite methods. The pipeline steel surface was modified with (heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane (HFTTMS). The effects of HCl concentration and the chemical etching time on the morphology of the pipeline steel surface and the wettability of the surface with distilled water were investigated. The results show that at certain HCl concentration, with the increase of the chemical etching time, the contact angles have a maximum value. At certain chemical etching time, the higher HCl concentration was, the severer the reaction between the pipeline steel surface and HCl solution was, and the surface roughness formed by the sandblasting roughening treatment decreased rapidly, resulting in the decrease of the contact angle. The sample sandblasted for 1.5 min and etched chemically for 1.5 h at 7 mol/L HCl can obtain the best surface fine structure. After the fluorination treatment, the biggest contact angle is 156.4°. © 2013 Elsevier B.V. All rights reserved. Source


Liu A.,China University of Petroleum - East China | Liu S.,Zhejiang University
Desalination and Water Treatment | Year: 2016

Backwashing process is critical for the normal operation of oilfield wastewater filter with walnut shell media. As the walnut shell media is different from the conventional media such as sand media in terms of surface physicochemical properties and the pollutants in oilfield wastewater are different from drinking water or municipal waste water, investigation on the backwash characteristics of walnut shell media used for the filtration of oilfield wastewater are necessary. In this paper, the performances of three backwashing modes including fluidization, hydraulic swirling, and blade stirring modes are experimentally evaluated for the dirty walnut shell media from an oilfield wastewater filter in Shengli oilfeild of China. The results show that blade stirring mode behaved well with the least backwashing water in comparison to the other two backwashing modes. The optimum rotating speed of blade for the blade stirring mode is about 120 rpm, and a sediment removal efficiency of near 90% is obtained when the residence time of filtration media is about 11 min in the vessel. Continuous backwashing operation of blade stirring mode is also demonstrated and the sediment removal efficiency of above 80% is obtained at a reasonable flow of clean water. © 2015 Balaban Desalination Publications. All rights reserved. Source


Song M.,Guangdong University of Technology | Song M.,Hong Kong Polytechnic University | Chen A.,Nanyang Technological University | Mao N.,China University of Petroleum - East China
Applied Thermal Engineering | Year: 2016

For an air source heat pump (ASHP) unit with a vertically installed multi-circuit outdoor coil, it is rarely possible to make the frost accumulations on each circuit's surface equal, leading to different frosting evenness values (FEVs) as a reverse cycle defrosting operation starts. On the other hand, uneven defrosting phenomenon was found and reported as many methods were developed to improve defrosting performance of ASHP systems, which may be attributable to the reverse cycle defrosting starting at an uneven frosting. Understanding of defrosting performance of an ASHP unit with a multi-circuit outdoor coil at different FEVs is of importance for ASHP units' application, but studies are scarce in the open literatures. In this paper, we report an experimental study on defrosting performance when frost accumulated on the surface of outdoor coil at different FEVs. This paper presents details of an experimental ASHP unit and the experimental conditions, followed by results, and conclusions. Finally, an increase of 6.8% in defrosting efficiency was confirmed when the FEV changed from 82.6% to 96.6%. © 2015 Elsevier Ltd. Source


Xu H.J.,Shanghai JiaoTong University | Xu H.J.,China University of Petroleum - East China | Zhao C.Y.,Shanghai JiaoTong University | Xu Z.G.,Shanghai JiaoTong University
Applied Thermal Engineering | Year: 2016

Forced convection in a mini/microchannel filled with microfoam is analytically studied in the condition of uniform but asymmetrical heat fluxes. Velocity slip, thermal slip, local thermal non-equilibrium (LTNE) effect, and asymmetric heat fluxes imposed on the two parallel-plates sandwiching the microfoams are especially considered. For two walls with different heat fluxes, solid and fluid temperatures at the boundary are equal to each other based on self-coupling conditions. Explicit expressions for velocity and temperatures of solid and fluid are derived and the analytical solution agrees well with existing references. This solution can predict velocity, temperatures, friction loss and thermal performance of porous microchannel for wide ranges of Knudsen number and HF ratio. With the increased Knudsen number, the friction factor gradually decreases and the decreasing amplitude in slip flow region is very large. With the increased shape factor, the dimensionless pressure drop sharply decreases for small shape factor, while its value gradually approaches 1 for large shape factor. A maximum Nusselt number exists with the increase in Knudsen number. Heat transfer can be enhanced by increasing effective Biot number or decreasing thermal conductivity ratio. The analytical solution is symmetrical on the axis ξσ=σ1 in the region 0σ<σξσ<σ+∞. © 2015 Elsevier Ltd. All rights reserved. Source


Zuo W.,China University of Petroleum - East China | Song Y.,Tongji University
Nonlinear Dynamics | Year: 2015

Dynamics of a general reaction–diffusion equation with distributed delay are considered. The effects of the weak kernel and the strong kernel on the dynamics of the system are both investigated. By analyzing the characteristic equations in detail and taking the average delay as a bifurcation parameter, the stability of the constant equilibrium and the existence of Hopf bifurcations are obtained. The absolute stability and the conditional stability can be explicitly determined by the coefficients of the linearized system. For the case of the strong kernel, the average delay may induce the stability switches, but it is not able to occur for the case of the weak kernel. The algorithm for determining the direction and stability of the bifurcating periodic solutions is derived. Finally, the obtained theoretical results are applied to several single-species models, and the numerical simulations are illustrated to verify the theoretical results. © 2014, Springer Science+Business Media Dordrecht. Source


Gu Y.-Y.,China University of Petroleum - East China | Yeung A.T.,University of Hong Kong
Journal of Hazardous Materials | Year: 2011

The sorption/desorption characteristics of heavy metals onto/from soil particle surfaces are the primary factors controlling the success of the remediation of heavy-metal contaminated soils. These characteristics are pH-dependent, chemical-specific, and reversible; and can be modified by enhancement agents such as chelates and surfactants. In this study, batch experiments were conducted to evaluate the feasibility of using citric acid industrial wastewater (CAIW) to desorb cadmium from a natural clay from Shanghai, China at different soil mixture pHs. It can be observed from the results that the proportion of cadmium desorbed from the soil using synthesized CAIW is generally satisfactory, i.e., >60%, when the soil mixture pH is lower than 6. However, the proportion of desorbed cadmium decreases significantly with increase in soil mixture pH. The dominant cadmium desorption mechanism using CAIW is the complexion of cadmium with citric acid and acetic acid in CAIW. It is concluded that CAIW can be a promising enhancement agent for the remediation of cadmium-contaminated natural soils when the environmental conditions are favorable. As a result, CAIW, a waste product itself, can be put into productive use in soil remediation. © 2011 Elsevier B.V. Source


Zhang C.,Tianjin University | Lv W.,Tsinghua University | Zhang W.,Tianjin University | Zheng X.,Tianjin University | And 5 more authors.
Advanced Energy Materials | Year: 2014

Graphene oxide is effectively reduced by H2S and a graphene/sulfur hybrid is simultaneously obtained. The resulting graphene sheets interlink, forming a curly and porous structure that accompanies a uniform distribution of sulfur on the graphene sheets. The product is a promising electrode for Li-S batteries and provides a novel strategy for the removal of H2S. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Jia S.,China University of Petroleum - East China
Gaoya Dianqi/High Voltage Apparatus | Year: 2014

The measurement of partial discharge (PD) is an effective method to monitor the insulation condition of stator windings. In this paper, an algorithm for partial discharge signal acquisition based on quasi-integration is proposed to overcome the defect in partial discharge time domain signal processing method, and to improve the accuracy and resolution of the partial discharge monitoring system. The influences of the quasi-integration parameters on pulse resolution and calculation are analyzed, the suited parameters are selected for generator PD monitoring and the algorithm is implemented through FPGA. A typical fault PD model and a on-line generator PD monitoring system are established in laboratory, and the rationality of the captured fault PD spectrum is analyzed. Simulations and experiments verify the feasibility and reliability of the proposed method for monitoring generator PD based on quasi-integration. Source


Zhixue S.,China University of Petroleum - East China | Zhilei S.,CAS Qingdao Institute of Oceanology | Zhilei S.,CAS Guangzhou Institute of Geochemistry | Hongjiang L.,Chengdu University of Technology | Xijie Y.,State Oceanic Administration
Petroleum Exploration and Development | Year: 2010

Authigenic carbonate cement is dominant in the Yanchang Formation sandstones of the middle and southern Ordos Basin. The main types of the carbonate cement are calcite, dolomite, ferrodolomite and ferrocalcite and the carbonate cement abundance decreases with depth increasing. Polarizing microscope and SEM reveal that carbonate cement occurs as pore-filling cement, replacement of feldspar, and thin rim surrounding the grains. The isotopic values of carbon and oxygen in the authigenic carbonates indicate that the precipitation of the carbonate cements was long, multi-phased, and varying in temperature. The origin of the substance for carbonate cements include the solution of the detrital carbonate, the illitization of smectite, the expelled fluid flow from the overlying shale, and the decomposition of the unstable dark-color minerals in reservoirs. The occluding of pores, the division of thick reservoir, the formation of calcium layers and the absence of solution of the carbonate cements significantly decrease the reservoir qualities all together. © 2010 Research Institute of Petroleum Exploration & Development, PetroChina. Source


Yue T.,China University of Petroleum - East China | Yue T.,Beijing University of Chemical Technology | Zhang X.,Beijing University of Chemical Technology
Soft Matter | Year: 2013

In this work we systematically investigate the pathways of the interaction between elastic vesicles and lipid membranes with the aid of computer simulation techniques. Different vesicle responses to the vesicle-membrane adhesion, including vesicle fusion, vesicle hemi-fusion, vesicle adhesion, vesicle endocytosis and vesicle rupture, are observed from our simulations. We also investigate how the pathways of vesicle-membrane interaction depend on the adhesion strength, and the membrane and vesicle properties. © The Royal Society of Chemistry 2013. Source


Dou Y.,Shandong University | Xu H.,China University of Petroleum - East China | Hao J.,Shandong University
Soft Matter | Year: 2013

Self-assembled structures such as nanotubes, nanobelts, nanofibers, and nanovesicles of surfactant-like peptides were obtained in water because of electrostatic interactions, hydrogen bonding, hydrophobic interactions and/or other weak interactions between peptide molecules. In this paper, we firstly prepared self-assembled nanotubes with very large aspect ratio and unfolded nanobelts by combining a peptide Ac-AAAAAAD-NH2 (A6D) with a zwitterionic surfactant, tetradecyldimethylaminoxide (C14DMAO), in aqueous solution at room temperature. The self-assembled nanotubes and nanobelts were characterized by negative-stained transmission electron microscopy (TEM), field emission-scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and cryo-TEM in detail. The optimal concentration ratio, R = cA6D/cC14DMAO, of nanotube formation was obtained to be 1:8. β-Sheet and random coil structures were proved to co-exist in both nanotubes and nanobelts by Fourier transform infrared (FT-IR) and circular dichroism (CD) measurements. Based on these results, we proposed the formation mechanism of the self-assembled nanostructures. Particularly, Au nanoparticles with diameter of 6.5 ± 1.1 nm from nanobelts of 8 mmol L-1 A6D/32 mmol L-1 C14DMAO and 6.8 ± 1.5 nm from nanotubes of 8 mmol L-1 A6D/64 mmol L-1 C14DMAO were synthesized, and mainly observed on the nanobelt surfaces or the nanotube walls. Moreover, the Au nanoparticles/nanotubes and Au nanoparticles/nanobelts were proved via UV-vis measurements by the characteristic peaks at around 520 nm. © 2013 The Royal Society of Chemistry. Source


Zhao F.-L.,China University of Petroleum - East China
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2010

For controlling water production from oil-bearing formation, water shutoff methods with and without water detection were developed. Because water detection doesn't need to be done and water production can be controlled in deep oil bearing formation, the latter method was more important and was reviewed here. In order to select water shutoff for oil well, the selective plugging agents and selective injection technologies were applied. The selective plugging agents and their action mechanisms were introduced, and how to utilize the characteristics of water production formation (high permeability, low flow resistance, high water saturation and easy to release pressure) and inject the plugging agent selectively into formation was analyzed. Some successful selective water shutoff pilot tests were given. This illustrates that water shutoff without water detection has a wide prospect of application and development. Source


Sun Y.,Argonne National Laboratory | An C.,China University of Petroleum - East China
Frontiers of Materials Science in China | Year: 2011

Advance in the synthesis of shaped nanoparticles made of gold and silver is reviewed in this article. This review starts with a new angle by analyzing the relationship between the geometrical symmetry of a nanoparticle shape and its internal crystalline structures. According to the relationship, the nanoparticles with well-defined shapes are classified into three categories: nanoparticles with single crystallinity, nanoparticles with angular twins, and nanoparticles with parallel twins. Discussion and analysis on the classical methods for the synthesis of shaped nanoparticles in each category are also included and personal perspectives on the future research directions in the synthesis of shaped metal nanoparticles are briefly summarized. This review is expected to provide a guideline in designing the strategy for the synthesis of shaped nanoparticles and analyzing the corresponding growth mechanism. © 2011 Higher Education Press and Springer-Verlag Berlin Heidelberg. Source


Wang F.,China University of Petroleum - East China | Shuai Y.,Harbin Institute of Technology | Tan H.,Harbin Institute of Technology | Zhang X.,Harbin Institute of Technology | Mao Q.,Harbin Institute of Technology
Solar Energy | Year: 2013

In this paper, Monte Carlo Ray Tracing (MCRT) and Finite Volume Method (FVM) coupling method is adopted to solve the radiation, conduction and convection coupled heat transfer problems of porous media receiver with multi-dish collector. The MCRT method is used to obtain the concentrated heat flux distribution on the fluid inlet surface of porous media receiver. The local thermal non-equilibrium (LTNE) model with concentrated solar irradiation on the fluid inlet surface is used for energy equations. FVM software FLUENT with User Defined Functions (UDFs) is used to solve the fluid phase and solid phase heat transfer problems. The effects of solar irradiance, air inlet velocity, average particle diameter, receiver radius and air properties on the temperature distribution are investigated. © 2013 Elsevier Ltd. Source


Davies R.J.,Northumbria University | Yang J.,Durham University | Yang J.,China University of Petroleum - East China | Hobbs R.,Durham University | Li A.,Durham University
Geology | Year: 2014

Marine gas hydrate is the largest carbon reservoir in the global organic carbon cycle, but there is limited knowledge of how hydrate is accreted in space and time. Three-dimensional seismic imaging of the dipping base of the deep-water marine gas hydrate from offshore Mauritania reveals extraordinary patterns of vertical chimneys and connected teardrop-shaped trails of both high and low seismic reflection amplitudes. The high-amplitude trails are interpreted as being caused by the downward transition from hydrate- to free gas-bearing sediments. Their teardrop form shows that gas emanating from the chimneys flowed updip along the base of the hydrate. The geometrically similar, lower-amplitude trails are possibly earlier flows that may have already converted to hydrate. For this area we propose a model of intermittent flow of gas to the base of the hydrate. Active flows were blocked updip by earlier, probably hydrate-clogged chimneys, and may have been laterally confined by flows that had already converted to hydrate that were in their path. The process of hydrate formation reduces sediment permeability and may suppress subsequent gas flows, resulting in the emergence of patterns of gas flow and hydrate accretion. © 2014 Geological Society of America. Source


Chao B.,CAS Shanghai Institute of Materia Medica | Lin S.,CAS Shanghai Institute of Materia Medica | Ma Q.,China University of Petroleum - East China | Lu D.,CAS Shanghai Institute of Materia Medica | Hu Y.,CAS Shanghai Institute of Materia Medica
Organic Letters | Year: 2012

A novel cascade reaction was developed for the synthesis of diverse members of a series of benzofuro[3,2-d]pyrimidine derivatives. The process utilizes readily prepared 3-chlorochromenones and various commercially available amidines and their analogues as starting materials. This tandem reaction is promoted by using a simple copper(I) reagent and involves a chemoselective Michael addition-heterocyclization-intramolecular cyclization sequence. © 2012 American Chemical Society. Source


Niu W.,China University of Petroleum - East China
Advances in Intelligent Systems and Computing | Year: 2013

Dealing with the present situation of geological body visualization, Firstly Delaunay triangulation principle and its region boundary segmentation algorithm in the presence of a large number of fault lines, complex boundary conditions is discussed. Then, Geostatistics, Kriging interpolation method is used to create a mathematical model of layer. In the end, with the modeling process, a specific example is used to better verify the geological layer model of the proposed modeling method. © 2013 Springer-Verlag. Source


Liu Q.,Yulin Normal University | Chen Q.,Yulin Normal University | Jiang D.,China University of Petroleum - East China
Physica A: Statistical Mechanics and its Applications | Year: 2016

This paper is concerned with the asymptotic properties of a stochastic delayed SIR epidemic model with temporary immunity. Sufficient conditions for extinction and persistence in the mean of the epidemic are established. The threshold between persistence in the mean and extinction of the epidemic is obtained. Compared with the corresponding deterministic model, the threshold affected by the white noise is smaller than the basic reproduction number R0 of the deterministic system. © 2016 Elsevier B.V. All rights reserved. Source


Wu M.,Shanxi Institute of Coal CAS Chemistry | Wu M.,University of Chinese Academy of Sciences | Yang J.,Shanxi Institute of Coal CAS Chemistry | Zhang Y.,China University of Petroleum - East China
Fuel | Year: 2012

The performance of four coal liquefaction residues (CLRs) in modification of petroleum paving asphalts were investigated. The 40-55 penetration grade modified asphalts were made. ASTM D5710-95 specifications were used to evaluate the modified asphalts. The influence of chemical composition and preparation methods were studied. The results indicate that the performance of CLR mainly depends on the amount and type of its miscible fraction that can dissolve or melt into the base asphalt. The addition of different CLRs in the base asphalt by a conventional hot mixing method results in the similar changes with respect to the softening point and penetration. However, it leads to the different change in ductility. The morphology analysis of the modified asphalt shows that the immiscibles from CLR are dispersed or suspended as single or clustered particles in the continuous asphalt phase. The miscibles of CLR in the base asphalt are active ingredients participating in the modification. The amount and the average molecular weight of CLR's tetrahydrofuran solubles have a close relationship with its performance. The dissolution or dispersion of CLR can be greatly improved with the help of solvent. © 2012 Elsevier Ltd. All rights reserved. Source


Sun X.,Peking University | Sun G.,China University of Petroleum - East China
2nd International Workshop on Education Technology and Computer Science, ETCS 2010 | Year: 2010

This paper presents a new edge detection algorithm based on calculating the difference value of two clusters. An edge is defined as a boundary that separates two adjacent regions that are relatively homogenous. For each image pixel, a window is first defined by placing the pixel at the center, and this window is partitioned into two regions respectively in four different directions. An appropriate function is then selected to estimate the difference between each pair of two adjacent regions and to calculate edge information in terms of edge stretch and direction by maximizing the difference value. Finally, the non-maxima suppression is adopted to derive the output edge map. Experiments on a variety of noise contaminated images show that the new algorithm is more robust under noisy conditions. In addition, the proposed algorithm can also be applied to color or multi-spectral images. © 2010 IEEE. Source


Wang D.,University of Toyama | Yang G.,University of Toyama | Ma Q.,University of Toyama | Wu M.,China University of Petroleum - East China | And 3 more authors.
ACS Catalysis | Year: 2012

Copper nanoparticles filled carbon nanotubes (CNTs) with varied tube diameters were prepared via a convenient sonication-assisted impregnation approach. CNTs and Cu nanoparticles filled CNTs were thoroughly investigated using transmission electron microscopy, Raman spectroscopy, N 2 adsorption, X-ray diffraction, and H 2 temperature programmed reduction. Confinement effects of CNTs, originated from its diameter and microstructure, on the filled Cu nanoparticles were discovered. For CNTs with smaller tube diameter, a consequential strong autoreduction for the confined Cu nanoparticles was observed, which showed a downward trend with the increasing anneal temperature. Methyl acetate (MeOAc) hydrogenation forming methanol and ethanol was chosen as model reaction to further explore the influence of CNTs confinement effects on the catalytic performance. In the case of catalysts derived from CNTs with smaller inner diameter (4-10 nm), their catalytic performance were improved after the CNTs heat treatment under Ar atmosphere and the optimum treatment temperature was 973 K. On the contrary, the CNTs catalysts with larger inner diameter (20-30 nm) exhibited reduced catalytic activity after the same heat treatment. In addition, the selectivity to ethanol from MeOAc was also found dependent on CNTs tube diameter. Furthermore, the Cu nanoparticles loaded outside of CNTs catalyst were prepared and compared with the Cu nanoparticles filled inside CNTs catalyst, and the latter exhibited higher catalytic activity because of the confinement effects of CNTs. All in all, when using CNTs as support materials, the likely synergistic effects created by CNTs diameter, the pretreatment on CNTs, and the nanocatalyst loaded inside or outside CNTs are responsible for the catalytic activity of the prepared catalysts. These findings propose an in-depth insight into the confinement of CNTs to the filled metal catalysts, and thus inspire the development of novel catalyst with beneficial catalytic performance. © 2012 American Chemical Society. Source


Guo J.-X.,Chinese Academy of Sciences | Zhang K.,Chinese Academy of Sciences | Zhang K.,University of British Columbia | Zhang Q.,China University of Petroleum - East China | Gao X.-S.,Chinese Academy of Sciences
CAD Computer Aided Design | Year: 2013

In this paper, the time-optimal feedrate planning problem under confined feedrate, axis velocity, axis acceleration, axis jerk, and axis tracking error for a high-order CNC servo system is studied. The problem is useful in that the full ability of the CNC machine is used to enhance the machining productivity while keeping the machining precision under a given level. However, the problem is computationally challenging. The main contribution of this paper is to approximate the problem nicely by a finite-state convex optimization problem which can be solved efficiently. The method consists of two key ingredients. First, a relationship between the tracking error and the input signal in a high-order CNC servo system is established. As a consequence, the tracking error constraint is reduced to a constraint on the kinematic quantities. Second, a novel method is introduced to relax the nonlinear constraints on kinematic quantities to linear ones. Experimental results are used to validate the proposed method. © 2013 Elsevier Ltd. All rights reserved. Source


Meng L.,Nanjing University of Aeronautics and Astronautics | Meng L.,China University of Petroleum - East China | Jiang B.,Nanjing University of Aeronautics and Astronautics
International Journal of Innovative Computing, Information and Control | Year: 2010

For a class of uncertain nonlinear systems with actuator faults, robust active fault-tolerant control is investigated based on the adaptive observer, feedback linearization, and back stepping design theory. Time-varying faults and bounded uncertainty are simultaneously considered in the paper. An adaptive observer is firstly constructed to estimate the faults and then a back stepping-based active fault-tolerant controller is designed to compensate for the faults. The main theoretical contributions of this work are a new fault updating law which relaxes the assumption conditions of the fault diagnosis observer and a new recursive control law for tracking the time-varying reference input signal. The asymptotical stability of the closed-loop fault-tolerant control system is proved by Lyapunov theorem. The numerical simulation results demonstrate the application and effectiveness of the proposed scheme. © ICIC International 2010. Source


Sheng L.,China University of Petroleum - East China | Gao M.,Shandong University of Science and Technology
Fuzzy Sets and Systems | Year: 2010

Abstract: This paper is concerned with the stability and stabilization problems for a class of nonlinear systems with Markovian jump parameters. The Takagi-Sugeno (T-S) fuzzy model is employed to represent the Markovian jump nonlinear systems with partly unknown transition probabilities. In contrast with the certain or uncertain transition probabilities investigated recently, the concept of partly unknown transition probabilities does not need any knowledge of the unknown elements. Some sufficient conditions for stochastic stability and stabilization conditions with a mode-dependent fuzzy controller are derived for the Markovian jump fuzzy systems in terms of linear matrix inequalities (LMIs). A numerical example is provided to illustrate the design developed in this paper. © 2010 Elsevier B.V. All rights reserved. Source


Wang X.,China University of Petroleum - East China | Zhang S.,Massachusetts Institute of Technology
PLoS ONE | Year: 2011

G-protein coupled receptors (GPCRs) participate in a wide range of vital regulations of our physiological actions. They are also of pharmaceutical importance and have become many therapeutic targets for a number of disorders and diseases. Purified GPCR-based approaches including structural study and novel biophysical and biochemical function analyses are increasingly being used in GPCR-directed drug discovery. Before these approaches become routine, however, several hurdles need to be overcome; they include overexpression, solubilization, and purification of large quantities of functional and stable receptors on a regular basis. Here we report milligram production of a human formyl peptide receptor 3 (FPR3). FPR3 comprises a functionally distinct GPCR subfamily that is involved in leukocyte chemotaxis and activation. The bioengineered FPR3 was overexpressed in stable tetracycline-inducible mammalian cell lines (HEK293S). After a systematic detergent screening, fos-choline-14 (FC-14) was selected for subsequent solubilization and purification processes. A two-step purification method, immunoaffinity using anti-rho-tag monoclonal antibody 1D4 and gel filtration, was used to purify the receptors to near homogeneity. Immunofluorescence analysis showed that expressed FPR3 was predominantly displayed on cellular membrane. Secondary structural analysis using circular dichroism showed that the purified FPR3 receptor was correctly folded with >50% α-helix, which is similar to other known GPCR secondary structures. Our method can readily produce milligram quantities of human FPR3, which would facilitate in developing human FPR as therapeutic drug targets. © 2011 Wang, Zhang. Source


Wang T.,China University of Technology | Yang G.,China University of Technology | Liu J.,China University of Technology | Yang B.,China University of Technology | And 4 more authors.
Applied Surface Science | Year: 2014

In this paper, a facile solvothermal method assisted orthogonal experimental was applied to synthesis mesoporous Fe2O 3/TiO2 heterostructured microsphere with the purpose of optimizing the preparation conditions. The as-prepared samples were characterized by TG, XRD, SEM, TEM, FT-IR, UV-vis DRS and N2 adsorption/desorption. On the basis of the above analysis, it was found that the mesoporous Fe2O3/TiO2 heterostructured microsphere has high crystallinity, ordered morphology, strong optical absorption, large surface area and enhanced catalytic activity. Furthermore, it also confirmed that orthogonal experimental design method was very efficient to optimize the preparation conditions for the synthesis of mesoporous Fe 2O3/TiO2 heterostructured microspheres. The experimental results show that the reaction temperature and molar ratio of Fe to Ti have the most influence on the photocatalytic performance. The optimized preparation conditions for the synthesis of Fe2O3/TiO 2 microspheres are reaction temperature at 140 °C, the amount of glucose of 3.4 g and the Fe:Ti molar ratio of 0.005:0.01. What's more, a tentative formation mechanism of mesoporous Fe2O3/TiO 2 microspheres and charge transfer mechanism are proposed. © 2014 Elsevier B.V. Source


Jiang K.,Chinese PLA General Hospital | Long Y.-Z.,Qingdao University | Chen Z.-J.,China University of Petroleum - East China | Liu S.-L.,Qingdao University | And 3 more authors.
Nanoscale | Year: 2014

Rapid hemostasis of solitary organs is still a big challenge in surgical procedures or after major trauma in both civilians and on the battlefield. Here, we report the first use of an airflow-directed in situ electrospinning method to precisely and homogeneously deposit a medical glue of n-octyl-2-cyanoacrylate (OCA) ultrathin fibers onto a wound surface to realize rapid hemostasis in dozens of seconds. In vivo and in vitro experiments on pig liver resection demonstrate that the self-assembled electrospun OCA membrane with high strength, good flexibility and integrity is very compact and no fluid seeping is observed even under a pressure of 147 mm Hg. A similar effect has been achieved in an in vivo experiment on pig lung resection. The results provide a very promising alternative for rapid hemostasis of solitary organs as well as other traumas, providing evidence that the postoperative drainage tube may not be always necessary for surgery in the near future. © 2014 the Partner Organisations. Source


Guanglei W.,China University of Petroleum - East China
Electronic Journal of Geotechnical Engineering | Year: 2013

Casing damage is a difficult technical problem, which severely restricts the efficient development of low-permeability reservoirs. Firstly, the cause of casing failure is studied and the results show that casing damage is closely related to seepage field changes. Shear failure damage, tensile damage and extrusive damage are all induced by seepage. Secondly, based on fluid-solid coupling theory, a calculation model of seepage fields and deformation field is established, the law of reservoir deformation and casing stress distribution is simulated in the process of injection-production. The results show an imbalance of effective stress field is easily produced near the fault and the lateral displacement of formation is increased, which causes casing failure. It is necessary to adopt high anti-collapsing ability casing to prevent casing damage near the fault. © 2013, EJGE. Source


Bao X.X.,China University of Petroleum - East China | Li C.L.,CAS Qingdao Institute of Oceanology | Xiong C.B.,State Oceanic Administration
Applied Physics Letters | Year: 2015

Modal analysis is an ongoing interdisciplinary physical issue. Modal parameters estimation is applied to determine the dynamic characteristics of structures under vibration excitation. Modal analysis is more challenging for the measured vibration response signals are contaminated with noise. This study develops a mathematical algorithm of structured low rank approximation combined with the complex exponential method to estimate the modal parameters. Physical experiments using a steel cantilever beam with ten accelerometers mounted, excited by an impulse load, demonstrate that this method can significantly eliminate noise from measured signals and accurately identify the modal frequencies and damping ratios. This study provides a fundamental mechanism of noise elimination using structured low rank approximation in physical fields. © 2015 AIP Publishing LLC. Source


He X.,Anhui University of Technology | Xie K.,Anhui University of Technology | Li R.,Anhui University of Technology | Wu M.,China University of Petroleum - East China
Materials Letters | Year: 2014

Ruthenium/mesoporous carbon (Ru/MC) composites for supercapacitors were synthesized from RuCl3 and peanut shell-derived MC by a microwave-assisted heating glycol reduction method. The specific capacitance of obtained Ru/MC composite increased with the increasing Ru mass loaded, maintaining 287 F g-1 even after 1000 cycles at 20% loading of Ru for Ru20/MC. The contribution of Ru nanoparticles reached 48.7% of the total capacitance. The energy density of Ru20/MC capacitor in 6 M KOH electrolyte only dropped from 10.5 Wh kg-1 to 9.8 Wh kg-1 with the energy density retention of 93.3% after 1000 cycles, showing excellent cycle stability. The results indicate that the one-step microwave-assisted glycol reduction of RuCl3 is a simple technique to the preparation of high performance Ru/MC composites for supercapacitors. © 2013 Elsevier B.V. Source


Yu L.,Peking University | Yu L.,China University of Petroleum - East China | Yang C.,Peking University | Hou Y.,Peking University
Nanoscale | Year: 2014

It is extremely desirable but challenging to develop exchange-coupled magnets with well-dispersed hard/soft phase and confined size to meet the high energy requirements of advanced magnets in modern industry and information technology. Here, we report a novel bottom-up strategy with two-step thermal decomposition and reductive annealing process to synthesize Nd 2Fe14B/α-Fe nanocomposites, in which effective control of the hard/soft magnetic phase size and proportion was achieved. It is worth noting that the composition, as well as phase distribution, can be readily tuned by changing the ratio between Nd-Fe-B-oxide and α-Fe. This work provides an effective approach to adjust the phase size and distribution for exchange-coupled, rare-earth nanomagnets, which can be fundamental for high energy magnets. © the Partner Organisations 2014. Source


Liu J.-L.,China University of Petroleum - East China | Feng X.-Q.,Tsinghua University
Acta Mechanica Sinica/Lixue Xuebao | Year: 2012

Elastocapillary phenomena involving elastic deformation of solid structures coupled with capillary effects of liquid droplets/films can be observed in a diversity of fields, e.g., biology and microelectromechanical systems (MEMS). Understanding the physical mechanisms underlying these phenomena is of great interest for the design of new materials and devices by utilizing the effects of surface tension at micro and nano scales. In this paper, some recent developments in the investigations on elastocapillary phenomena are briefly reviewed. Especially, we consider the deformation, adhesion, self-assembly, buckling and wrinkling of materials and devices induced by surface tensions or capillary forces. The main attention is paid to the experimental results of these phenomena and the theoretical analysis methods based on continuum mechanics. Additionally, the applications of these studies in the fields of MEMS, micro/nanometrology, and biomimetic design of advanced materials and devices are discussed. © The Chinese Society of Theoretical and Applied Mechanics and Springer-Verlag Berlin Heidelberg 2012. Source


Liu J.-L.,China University of Petroleum - East China | Xia R.,Wuhan University
Acta Mechanica Sinica/Lixue Xuebao | Year: 2013

In this study, we developed a general method to analytically tackle a kind of movable boundary problem from the viewpoint of energy variation. Having grouped the adhesion of a micro-beam, droplet and carbon nanotube (CNT) ring on a substrate into one framework, we used the developed line of reasoning to investigate the adhesion behaviors of these systems. Based upon the derived governing equations and transversality conditions, explicit solutions involving the critical parameters and morphologies for the three systems are successfully obtained, and then the parameter analogies and common characteristics of them are thoroughly investigated. The presented method has been verified via the concept of energy release rate in fracture mechanics. Our analyses provide a new approach for exploring the mechanism of different systems with similarities as well as for understanding the unity of nature. The analysis results may be beneficial for the design of nano-structured materials, and hold potential for enhancing their mechanical, chemical, optical and electronic properties. © 2012 The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg. Source


Zhang W.,Shandong University of Science and Technology | Chen B.-S.,National Tsing Hua University | Tang H.,Shandong University | Sheng L.,China University of Petroleum - East China | Gao M.,Shandong University of Science and Technology
IEEE Transactions on Automatic Control | Year: 2014

This technical note studies the nonlinear stochastic H∞ control of Itô-type differential systems with all the state, control input and external disturbance-dependent noise (x,u,v-dependent noise for short). A sufficient condition is given for the finite/infinite horizon H ∞ control of such a system by means of an Hamilton-Jacobi inequality (HJI) instead of three coupled Hamilton-Jacobi equations (HJEs) as in previous literature. © 2013 IEEE. Source


Liu Y.,China University of Petroleum - East China
Journal of Intelligent and Fuzzy Systems | Year: 2015

Colleges and universities in our country keep on enlarging the number of new students. As a result, a serious of problems appears. Under such circumstances, the topic of education effectiveness becomes a very hot issue. In colleges and universities, classroom instruction still is the main teaching method. Its effectiveness, to a large extent, reflects and determines the education quality of colleges and universities. And, teacher's classroom instruction is the most important part, which determines the fostering level of talents, affects teachers and students' life quality. Hence, evaluation of teacher's classroom instruction effectiveness of colleges and university has a very important influence on propelling teacher's teaching reform and improving the education quality. In this paper, we investigate the multiple attribute decision making with intuitionistic fuzzy information. Motivated by the ideal of dependent aggregation, we develop the dependent intuitionistic fuzzy Einstein weighted average(DIFEWA) operator, in which the associated weights only depend on the aggregated intuitionistic fuzzy arguments and can relieve the influence of unfair intuitionistic fuzzy arguments on the aggregated results by assigning low weights to those 'false' and 'biased' ones and then apply them to develop some approaches for multiple attribute decision making with intuitionistic fuzzy numbers. Finally, an illustrative example for evaluating the foreign language teaching effectiveness is given to verify the developed approach and to demonstrate its practicality and effectiveness. © 2015-IOS Press and the authors. Source


Liu H.,Harbin Institute of Technology | Shen Y.,Harbin Institute of Technology | Zhao X.,China University of Petroleum - East China
Nonlinear Analysis: Hybrid Systems | Year: 2013

This paper concerns the asynchronous finite-time H∞ control problem for a class of switched linear systems with time-varying disturbances. The asynchronous switching means that the switchings between the candidate controllers and system modes are asynchronous. By using the Average Dwell Time (ADT) and Multiple Lyapunov Functions (MLFs) technologies, some sufficient conditions which can guarantee that the corresponding closed-loop system is finite-time bounded with a prescribed H∞ performance index via asynchronously switched control, are derived for the switched linear systems. Unlike the traditional Lyapunov asymptotic stability, there is no requirement of negative definiteness (or semidefiniteness) on the derivative of Lyapunov-like function. Moreover, a set of mode-dependent dynamic state feedback controllers are designed. Finally, two examples are provided to verify the efficiency of the proposed method. © 2012. Source


Zhao X.,China University of Petroleum - East China | Liu H.,Harbin Institute of Technology | Wang Z.,Harbin Institute of Technology
International Journal of Systems Science | Year: 2013

This article is concerned with the disturbance attenuation properties of a class of switched linear systems by using a mode-dependent average dwell time (MDADT) approach. The proposed switching law is less strict than the average dwell time (ADT) switching in that each mode in the underlying system has its own ADT. By using the MDADT approach, a sufficient condition is obtained to guarantee the exponential stability with a weighted H ∞ performance for the underlying systems. A numerical example is given to show the validity and potential of the developed results on improving the disturbance attenuation performance. © 2013 Copyright Taylor and Francis Group, LLC. Source


Zhang L.,Shandong University | Xu B.,Shandong University of Technology | Xue Y.,China University of Petroleum - East China | Gao H.,Shandong University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

In order to solve the fault location problem of single phase grounding fault in non-solidly earthed distribution network, a new fault location method based on transient component of line voltage and zero-mode current was presented. This method is realized by the feeder automation (FA) system and does not require additional equipment. The product of transient line voltage after Hilbert transformation and transient zero-mode current is defined as the parameter of fault direction, calculated by the feeder terminal unit (FTU). The fault section is located by master station according to opposite polarity of direction parameter before and after fault point. The algorithm of detecting single phase grounding fault and confirming the fault phase was introduced. Results of digital simulation and experiment demonstrated the accuracy and feasibility of this method. © 2012 Chinese Society for Electrical Engineering. Source


Liu H.,Harbin Institute of Technology | Shen Y.,Harbin Institute of Technology | Zhao X.,China University of Petroleum - East China
Journal of the Franklin Institute | Year: 2013

In this paper, finite-time stabilization and boundedness (FTSB) problems are investigated. Unlike the existing approach based on time-dependent switching strategy, in which the switching instants must be given in advance, largest region function strategy, i.e., state-dependent switching strategy, is adopted to design the switching signal. Based on multiple Lyapunov-like functions method, some sufficient conditions are provided for FTSB of switched linear system and the corresponding sliding motion problem is also considered. Finally, two examples are given to verify the efficiency of the proposed methods. © 2012 The Franklin Institute. Source


Guo Z.,University of Calgary | Dong M.,University of Calgary | Chen Z.,University of Calgary | Yao J.,China University of Petroleum - East China
Industrial and Engineering Chemistry Research | Year: 2013

Polymer flooding of heavy oils on the laboratory scale shows appreciable incremental tertiary oil recovery. In reality, however, this high recovery efficiency usually cannot be achieved in the field due mainly to extremely unfavorable mobility ratio and reservoir heterogeneity. The former promotes viscous fingering while the latter induces channeling; hence both of these factors make the displacement process less efficient. This paper identifies the dominant scaling groups for polymer flooding currently conducted in western Canadian heavy oil reservoirs. Twenty-eight dimensionless scaling groups governing the process of polymer flooding for enhanced heavy oil recovery were derived using inspectional analysis, and a fully tuned numerical model for polymer flooding of a heavy oil sample in a two-dimensional sand pack was then developed to validate the effectiveness of these scaling groups. A good agreement among different cases with the same group values was observed, showing the validity of the scaling groups. The effect of each scaling group on oil recovery was examined by numerical sensitivity analysis. By doing so, nine scaling groups dominating polymer flooding enhanced heavy oil recovery were identified. These dominant scaling groups can be used to design scaled experiments to predict field-scale oil recovery by polymer flooding in heavy oil reservoirs. © 2012 American Chemical Society. Source


Liu D.,Shandong University of Science and Technology | Liu C.,China University of Petroleum - East China
China Petroleum Processing and Petrochemical Technology | Year: 2013

Diatomite-dispersed NiMoW catalyst was prepared and characterized, and the activity of catalyst samples was tested during the HDS reaction of FCC diesel. Sulfur compounds in the feedstock and the hydrogenated products obtained over different catalysts were determined by GC-PFPD. The test results showed that the diatomite-dispersed NiMoW catalyst had high hydrodesulfurization activity for FCC diesel, which could be contributed to the excellent hydrogenation performance of the said catalyst. Characterization of catalyst by TEM and XRD indicated that the diatomite-dispersed NiMoW catalyst possessed higher layer stacking, larger curvature of MoS2 or WS2, and segregated Ni3S2 crystals relative to the supported catalyst. This kind of structure leads to high hydrogenation activity of the diatomite-dispersed NiMoW catalyst. Source


Zhang L.-Q.,China University of Petroleum - East China
Journal of Chengdu University of Technology (Science and Technology Edition) | Year: 2011

The data from mineralogy, petrology, isotopic geochemistry, inclusion thermometry and well logging are used to investigate distribution, origin and effect on reservoir properties of calcite cements in overpressure sandstones of Paleogene Anjihaihe Formation on the south margin of Junggar Basin. The carbonate cemented layers in sandstones are distributed over three areas: the upper and lower parts of the overpressure zone's top surface, the margins of sandstone bodies or the enrichment zone of sandstones within the overpressure zone and adjacent to the thick high pressure mudstone, the thin layers of sandstone in thick mudstone inside the overpressure zone. The ferrocalcite cements in connected-crystals form, which are proved to be mainly external, firstly deposit near the sandstone margins. Due to the inhibiting effect of overpressure on diagenesis, the sandstone cements in the overpressure zone of Anjihaihe Formation are mostly ferrocalcite cements, while the ferrodolomite and quartz overgrowth are seldom. The ferrous calcite cements formed at the late diagenetic stage. Due to the effect of both organic matter evolution and fluid migration, the 5 13CpDB are mostly - 10‰ ∼ - 2‰ and the 5 18 O PDB are mostly - 15‰ ∼ - 10‰. When the formation water flows near margins of sandstone bodies, the calcite deposits and leads to the calcite's concentration near margins of sandstone. In the sandstone with low content of clay matrix, the content of ferrocalcite has a negative correlation with porosity and permeability. In addition, the depth interval with negative migration of 5 13C PDB is related to the secondary pore zone formed by organic acid corrosion. Source


Sheng L.,China University of Petroleum - East China | Gao M.,Shandong University of Science and Technology | Zhang W.,Shandong University of Science and Technology
IET Control Theory and Applications | Year: 2013

This study is concerned with the stability analysis and stabilisation of linear stochastic systems with Markovian switching by using the spectral technique. The notion of spectrum for Markovian jump linear stochastic systems (MJLSSs) is introduced and the relationship between the spectrum and the asymptotical mean-square stability is revealed. As applications, a necessary and sufficient condition for regional stability of MJLSSs and a result on generalised Lyapunov equations are derived. Examples are presented to illustrate the results established. © The Institution of Engineering and Technology 2013. Source


Zhang G.,China University of Petroleum - East China | Chen X.,Shandong University
Liquid Crystals | Year: 2013

Lyotropic liquid crystals (LLCs) formed in tetraethylene glycol lauryl ether-water system by the addition of 1-alkyl-3-methylimidazolium tetrafluoroborate ([CnMim][BF4], n = 2, 4, 6, 8, 10) are characterised by polarised optical microscopy and small-angle X-ray scattering techniques. A small number of [CnMim][BF4] molecules can be solubilised in the liquid crystal without changing the lamellar type. These imidazolium salts are considered as an ideal kind of modifiers for the ordered structure. With different lengths of alkyl chains, [CnMim][BF4] molecules appear in various domains of ordered assemblies: in the water layer for [C2Mim][BF4], in the water layer as well as in the polar domain for [C4Mim][BF4] and in the apolar domain for the other imidazolium salts with long alkyl chains. Diverse distributions of [CnMim][BF4] molecules in the inner structure bring about their specific influence on the lamellar phase. These results enlighten the use of diverse alkyl-substituted imidazolium salts in modulating LLC and other assemblies and also enrich the aggregation behaviour of these assemblies. © 2013 Copyright Taylor and Francis Group, LLC. Source


Bao X.,China University of Petroleum - East China
Journal of Vibroengineering | Year: 2014

Accurate estimate of the modal parameters of a structure is crucial to many practical engineering problems, such as finite element model updating/validation, damage detection, etc. As the measured data are inevitably contaminated by noise, accurately estimating modal parameters has been a difficult task. This article proposes an extended Prony's method, which includes model order determination and noise reduction procedures before implementing the classical Prony's method to estimate the modal frequencies and damping ratios for a jacket type offshore platform. In determining the model order, singular value decomposition (SVD) of a Hankel matrix, together with a model order indicator is applied. For removing noise from the measured signal to yield a filtered signal with a known model order, a structured low rank approximation (SLRA) method for the Hankel matrix is carried out. To validate the applicability of the proposed approach, experimental studies based on a steel model of jacket type offshore platform were firstly performed. Using measured data from four accelerometers mounted at different locations of the test model, it is found that the modal parameters including translational mode (x or y direction) and torsional mode estimated from the filtered signals of the four locations separately are in excellent agreement. Using sea test data measured from accelerometers mounted at two different locations of the test platform, it is also found that the modal parameters estimated from the filtered signals of the two locations separately are in excellent agreement. It is concluded that the proposed approach is very accurate on estimating the modal parameters. A significant improvement can be achieved when the filtered, rather than the originally measured, signals are used. © JVE INTERNATIONAL LTD. Source


Zhang H.Y.,China University of Petroleum - East China
Advanced Materials Research | Year: 2013

Chinese economy has had great development since the reform and opening up, but as we know, the development is an extensive economic growth, which brought serious environmental pollution problems, so, the coordinated development of economy-environment composite system is becoming more and more important. And if we want so, the first thing is to evaluate the coordinated development of economy-environment composite system. This paper takes the provinces in china as the study object, and collects some data from 2000 to 2009 of 29 provinces in china, base on which this paper builds some evaluation models, such as development degree model, coordination degree model, and coordinated development model, to evaluate the coordinated development of economy-environment system among Chinese provinces. © (2013) Trans Tech Publications, Switzerland. Source


Zhang P.-Y.,China University of Petroleum - East China
Advanced Materials Research | Year: 2013

FAQ system is a question answering system which finds the question sentence from question-answer collection and then returns its corresponding answer to user. The task of matching questions to corresponding question-answer pairs has become a major challenge in FAQ system. This paper proposes a method for sentence similarity metric between questions according to its semantic similarity as well as the length of question length. Experiments show that this method can improve the accuracy and intelligence of answering system, has some practical value. © (2013) Trans Tech Publications, Switzerland. Source


Jian L.,Dalian University of Technology | Jian L.,China University of Petroleum - East China | Gao C.,Zhejiang University | Xia Z.,Dalian University of Technology
Steel Research International | Year: 2011

Blast furnace is one of the most complex industrial reactors and remains some unsolved puzzles, such as blast furnace automation, prediction of the inner thermal state, etc. In this work, a sliding-window smooth support vector regression model is presented to address the issue of predicting the blast furnace inner thermal state, represented by the silicon content in blast furnace hot metal in the context. Different from the traditional numerical prediction models of silicon, the constructed SW-SSVR model is devoted to predicting the changing trend of silicon and exhibits good performance with high percentage of successful trend prediction, competitive computational speed and timely online service. Additionally, some sharp fluctuation trend in the silicon test data can also be followed well by the SW-SSVR model, which is always difficult for traditional data-driven based silicon prediction models. All of these indicate that the SW-SSVR model is a good candidate to predict the change of blast furnace inner thermal state, and may provide a guide for operators to take proper action on operating blast furnace in advance. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Gao C.,Zhejiang University | Jian L.,China University of Petroleum - East China | Liu X.,China Jiliang University | Chen J.,Zhejiang University | Sun Y.,Zhejiang University
IEEE Transactions on Neural Networks | Year: 2011

The multidimensional blast furnace system is one of the most complex industrial systems and, as such, there are still many unsolved theoretical and experimental difficulties, such as silicon prediction and blast furnace automation. For this reason, this paper is concerned with developing data-driven models based on the Volterra series for this complex system. Three kinds of different low-order Volterra filters are designed to predict the hot metal silicon content collected from a pint-sized blast furnace, in which a sliding window technique is used to update the filter kernels timely. The predictive results indicate that the linear Volterra predictor can describe the evolvement of the studied silicon sequence effectively with the high percentage of hitting the target, very low root mean square error and satisfactory confidence level about the reliability of the future prediction. These advantages and the low computational complexity reveal that the sliding-window linear Volterra filter is full of potential for multidimensional blast furnace system. Also, the lack of the constructed Volterra models is analyzed and the possible direction of future investigation is pointed out. © 2006 IEEE. Source


Liu J.-L.,China University of Petroleum - East China | Xia R.,Key Laboratory of Transients in Hydraulic Machinery | Zhou Y.-T.,Yonsei University
Chinese Physics Letters | Year: 2011

Nanowire stiction is a crucial bottleneck for the development of M/NEMS devices. We present a model of a nano-beam stuck to the substrate in consideration of both surface elasticity and residual surface stress. The critical detachment length can be derived from the transversality condition using the variational method. The effects of the surface parameters on the adhesion of the nano-beam are discussed in detail. These analyses provide some suggestions for engineers in the design and fabrication of more accurate M/NEMS instruments. © 2011 Chinese Physical Society and IOP Publishing Ltd. Source


Zhang D.-Z.,China University of Petroleum - East China
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2014

To provide building blocks for high-performance Micro-electro-mechanical System (MEMS) devices, Layer-by-layer (LbL) self-assembly of Single-walled Carbon Nanotube (SWNT)/polymer films was proposed and their properties were characterized and tested. The surface morphologies of the SWNT/polymer films observed under a Scanning Electron Microscope(SEM) show high strength, dense and random network structures. Raman spectra of all characteristic peaks for the SWNT in radial breathing mode, disorder mode and tangential mode demonstrate the presence of the SWNT in overall good quality and a loading state. Real time Quarts Crystal Microbalance(QCM) online monitoring illustrates that the deposition thickness and the SWNT loading fraction in the nanocomposite can be controlled in a large range based on LbL sequential deposition process. When the cycle number of polymers increase from 0 to 5, the average film thickness increases from 6.31 to 111.59 nm, and the SWNT volume fraction decreases from 72.35% to 14.78%. In addition, the electric properties of the SWNT/polymer films under the influence of SWNT loading fraction and film thickness were investigated through current-voltage characterization. These results provide experimental and theoretical bases for potential applications of SWNT films in MEMS devices. Source


Chen H.,CAS National Astronomical Observatories | Zhang J.,CAS National Astronomical Observatories | Li L.,CAS National Astronomical Observatories | Ma S.,China University of Petroleum - East China
Astrophysical Journal Letters | Year: 2016

Triggering mechanisms of solar eruptions have long been a challenge. A few previous case studies have indicated that preceding gentle filament merging via magnetic reconnection may launch following intense eruption, according to the tether-cutting (TC) model. However, the detailed process of TC reconnection between filaments has not been exhibited yet. In this work, we report the high-resolution observations from the Interface Region Imaging Spectrometer (IRIS) of TC reconnection between two sheared filaments in NOAA active region 12146. The TC reconnection commenced on ∼15:35 UT on 2014 August 29 and triggered an eruptive GOES C4.3-class flare ∼8 minutes later. An associated coronal mass ejection appeared in the field of view of the Solar and Heliospheric Observatory/LASCO C2 about 40 minutes later. Thanks to the high spatial resolution of IRIS data, bright plasma outflows generated by the TC reconnection are clearly observed, which moved along the subarcsecond fine-scale flux tube structures in the erupting filament. Based on the imaging and spectral observations, the mean plane-of-sky and line-of-sight velocities of the TC reconnection outflows are separately measured to be ∼79 and 86 km s-1, which derives an average real speed of ∼120 km s-1. In addition, it is found that spectral features, such as peak intensities, Doppler shifts, and line widths in the TC reconnection region are evidently enhanced compared to those in the nearby region just before the flare. © 2016. The American Astronomical Society. All rights reserved.. Source


Ding N.,Binzhou University | Fang J.-H.,China University of Petroleum - East China
Communications in Theoretical Physics | Year: 2010

Two types of Mei adiabatic invariants induced by perturbation of Mei symmetry for nonholonomic controllable mechanical systems are reported. Criterion and restriction equations determining Mei symmetry after being disturbed of the system are established. Form and existence condition of Mei adiabatic invariants are obtained. © Chinese Physical Society and IOP Publishing Ltd. Source


Sun J.,Northeast Normal University | Sun J.,China University of Petroleum - East China | Pei D.,Northeast Normal University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2012

This Letter considers the curvature conditions of AW(k)-type (k=1,2,3) null Cartan curves, and investigates null Cartan Bertrand curves. We show that null Cartan Bertrand curves are AW(k)-type (k=1,2,3) curves in Minkowski 4-space. © 2012 Elsevier B.V. All rights reserved. Source


Zhang X.-M.,South China University of Technology | Zhang X.-M.,China University of Petroleum - East China | Chen G.-H.,South China University of Technology
Safety Science | Year: 2011

Studies on domino effect in chemical industrial parks are crucial for avoiding accident escalation. Domino effect network (DEN) may be formed as a consequence of widely distribution of major hazard installations (MHIs) in chemical industrial parks. To decrease accident scale and prevent catastrophic consequence, it is essential to cut off the relations between entities in a DEN during accident periods. Focusing on this aspect, based on the conceptual model of discrete isolated island (DII) discussed, an objective function was brought out to evaluate the linking level of the whole park; while to help determine the dominant MHI (namely Domino hub in a DEN), equations for calculating accident escalation factor (AEF) was advanced. Further, an algorithm was developed for the proposed model. Application showed that the proposed model, which is capable of providing possible ways to determine the dominant MHI contributing to domino effect, was quite useful and effective for choosing technical prevention measures to enhance the safety level of chemical industrial parks. © 2010 Elsevier Ltd. Source


Bai P.,China University of Petroleum - East China
Electronic Journal of Geotechnical Engineering | Year: 2013

A full recognition of the role of rock drillability plays a significant role in bit selection, drilling parameters optimization and prediction of penetration rate in rock drilling projects. Drillability is related to geomechanical characteristics of the rock, including hardness, uniaxial compressive strength (UCS), elasticity and plasticity, Young's modulus etc. With nonlinear regression analysis on each factor and multi-variables linear regression on collectivity, this paper presents a stepwise multi-elemental regression model between drillability and rock mechanics parameters. Based on the theoretical model, drillability of actual conditions in which mechanics parameters were affected by enclosing pressure, fluid filtration can be obtained. In addition, interpretation model of drillability based on compressive wave velocity amended by in-site acoustic logging data was established, and the prediction accuracy reached a high accuracy, comparing the calculated value with measured drillability. © 2013 ejge. Source


Zhang H.,Shanghai Maritime University | Lu C.,China Electric Power Research Institute | Sun Z.,China University of Petroleum - East China
Applied Physics Letters | Year: 2015

This paper develops a self-biased magnetoelectric (ME) heterostructure FeCuNbSiB/Terfenol-D/Be-bronze/Pb(Zr,Ti)O3 (PZT) by sandwiching a nonmagnetic elastic Be-bronze plate between an piezoelectric PZT plate and a magnetization-graded FeCuNbSiB/Terfenol-D layer. The Be-bronze plate severs as the resonance frequency determining element of the ME heterostructure. By using the magnetization-graded magnetostrictive layer and the elastic Be-bronze plate, seven large peaks of ME response with magnitudes of 0.3-10 (V/cm Oe) in 1-70 kHz range are observed at zero-biased magnetic field. This demonstrates that the proposed multi-peak self-biased heterostructure may be useful for multifunctional devices such as multi-frequency energy harvesters or low-frequency ac magnetic field sensors. © 2015 AIP Publishing LLC. Source


Sheng L.,China University of Petroleum - East China | Gao M.,Shandong University of Science and Technology
International Journal of Systems Science | Year: 2013

This article discusses the robust stability problem for a class of uncertain Markovian jump discrete-time neural networks with partly unknown transition probabilities and mixed mode-dependent time delays. The transition probabilities of the mode jumps are considered to be partly unknown, which relax the traditional assumption in Markovian jump systems that all of them must be completely known a priori. The mixed time delays consist of both discrete and distributed delays that are dependent on the Markovian jump modes. By employing the Lyapunov functional and linear matrix inequality approach, some sufficient criteria are derived for the robust stability of the underlying systems. A numerical example is exploited to illustrate the developed theory. © 2013 Copyright Taylor and Francis Group, LLC. Source


Ma C.,CAS Research Center for Eco Environmental Sciences | Xue W.,CAS Research Center for Eco Environmental Sciences | Li J.,CAS Research Center for Eco Environmental Sciences | Xing W.,China University of Petroleum - East China | Hao Z.,CAS Research Center for Eco Environmental Sciences
Green Chemistry | Year: 2013

A series of ordered mesoporous carbon (OMC)-supported Au catalysts were successfully prepared by nano-replication, followed by colloidal gold deposition method. Structural analysis showed that the mesopore sizes of the catalysts can be tuned controllably in the range of 3.2-7.6 nm by adjusting the dosage of boric acid used to prepare the carbon supports. TEM observations revealed that the Au nanoparticles were dispersed uniformly in the mesopore channels of the carbon supports. These Au/OMC catalysts were tested for the aerobic oxidation of glucose to produce gluconic acid at 40°C and pH 9. As demonstrated by the structural analysis and reaction results, the activities of these catalysts were closely related to their mesopore sizes. The catalyst with a mesopore size of 5.4 nm exhibited a superior catalytic activity with a TOF of 4.308 mol glucose molAu -1 s-1 to the catalysts reported previously by other researchers. This high activity was mainly ascribed to its unique structure, consisting of 5.4 nm mesopore channels incorporated with 3.3 nm Au nanoparticles, which facilitates contact between glucose molecules and Au nanoparticles. Besides, the abundant active oxygen species existing on this catalyst surface also promote glucose oxidation. © 2013 The Royal Society of Chemistry. Source


Zhan K.,China University of Petroleum - East China | Li X.,University of Science and Technology of China
Optics Communications | Year: 2013

We theoretically investigate the defect modes and defect solitons supported by optically induced lattices in highly saturable nonlinear media with quadratic electro-optic effect. It is shown that positive and negative defect modes bifurcate from the right and left edge of each band into the bandgaps, respectively, and the distances between the eigenvalues of defect mode and band edge increase with the defect strength. Defect solitons bifurcate from every infinitesimal linear defect mode. When the defect is attractive, lower power defect soliton can propagate stably, but the soliton with high intensity are unable. In repulsive defects, defect soliton are stable in entire regions of their existence in lower bandgaps but only the higher power solitons are stable in higher bandgaps. Especially, when the repulsive defect is strong, both the defect mode and soliton power diagram branches terminate on the right edge of this gap and then appear in higher band gaps, and these solitons can propagate stably in whole soliton existing regime. © 2013 Elsevier B.V. All rights reserved. Source


Cao H.,University of Hong Kong | Li M.,University of Hong Kong | Dang H.,China University of Petroleum - East China | Gu J.-D.,University of Hong Kong
Methods in Enzymology | Year: 2011

Up to date, numerous studies have shown that the community structure of aerobic ammonia oxidizers including ammonia-oxidizing Betaproteobacteria (Beta-AOB) and ammonia-oxidizing archaea (AOA) and, more recently, the anaerobic ammonium-oxidizing (anammox) bacteria is responsive to environmental conditions including salinity, pH, selected metal ions, concentrations of inorganic nitrogen, total phosphorus, the ratio of organic carbon and nitrogen, and sedimentological factors such as the sediment median grain size. Identification of these responses to known anthropogenic pollution is of particular interest to better understand the growth dynamics and activities of nitrogen transforming microorganisms in marine environments. This chapter discusses currently available methods including molecular ecological analysis using clone library constructions with specific molecular genetic markers for delineating community changes of Beta-AOB, AOA, and anammox bacteria. Using data on ammonia-oxidizing microbial community structures from Jiaozhou Bay in North China and three marine environments with anthropogenic pollution gradients in South China from coastal Mai Po Nature Reserve of Hong Kong to the South China Sea as examples, statistical analyses packages (DOTUR, UniFrac, and Canoco) are presented as useful tools to illustrate the relationship between changes in nitrogen metabolizing microbial communities and established environmental variables. © 2011 Elsevier Inc. All rights reserved. Source


Liu J.,China University of Petroleum - East China | Zuo W.,Jilin University | Mei Y.,South China University of Technology
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2012

The surface tension of liquid is generally negligible at macroscopic scale but can cause a lot of anomalous deformation of slender structures at small scales. In this study, we presented the analytical deflection solutions of a rectangular plate with two clamped ends and a clamped circular plate based upon the principle of superposition, where a droplet was deposited onto the micro-plate surfaces. In the light of these analytical solutions, the abnormal bending of the plate when the droplet is placed at different positions of the top or bottom surface of the plate was discussed in detail. The FEM (finite element method) simulation was also conducted, and the results show excellent agreement with our analytical solutions. We also put to use the FEM simulation to explore the displacement field of a more general plate with complex boundary conditions and complicated loads originating from the droplet, and the folding of a soft membrane caused by a droplet was also simulated. This investigation is beneficial to understand the physical mechanisms underlying the droplet-induced deformation of slender structures, and is of great interest for the design of new materials and devices by utilizing the effects of surface tension at micro and nano scales. © 2012 Elsevier B.V. Source


Liu D.,China University of Petroleum - East China | Liu D.,Hong Kong Polytechnic University | Zhao F.-Y.,Hubei Engineering University | Yang H.-X.,Hong Kong Polytechnic University | Tang G.-F.,Hunan University
Energy | Year: 2015

In the present study, a thermoelectric mini cooler coupling with a micro thermosiphon cooling system has been proposed for the purpose of CPU cooling. A mathematical model of heat transfer, depending on one-dimensional treatment of thermal and electric power, is firstly established for the thermoelectric module. Analytical results demonstrate the relationship between the maximal COP (Coefficient of Performance) and Qc with the figure of merit. Full-scale experiments have been conducted to investigate the effect of thermoelectric operating voltage, power input of heat source, and thermoelectric module number on the performance of the cooling system. Experimental results indicated that the cooling production increases with promotion of thermoelectric operating voltage. Surface temperature of CPU heat source linearly increases with increasing of power input, and its maximum value reached 70°C as the prototype CPU power input was equivalent to 84W. Insulation between air and heat source surface can prevent the condensate water due to low surface temperature. In addition, thermal performance of this cooling system could be enhanced when the total dimension of thermoelectric module matched well with the dimension of CPU. This research could benefit the design of thermal dissipation of electronic chips and CPU units. © 2015 Elsevier Ltd. Source


Kong X.Q.,Liaoning University of Technology | Liu J.L.,China University of Petroleum - East China | Zhang W.J.,Liaoning University of Technology | Qu Y.D.,Liaoning University of Technology
AIP Advances | Year: 2015

Mosquitoes possess a remarkable ability to stand effortlessly and walk freely on water surfaces because their six legs provide a large force to support the body weight. This study is focused on the role of the tarsus (the distal segment of the mosquito leg) because it was observed that normally only the tarsi make contact with water. The maximum value of the supporting force of the tarsus (6 mm long) in contact with water is estimated as 492 ± 5 μN, nearly 20 times the body weight of the mosquito, whereas the value for the whole leg (11 mm) is about 23 times the body weight. We demonstrate that the huge force provided by the tarsus originates from its flexibility, which ensures that the leg does not easily pierce the water. Adjustment of the initial stepping angle of the tarsus assists the mosquito to control the supporting force. These findings help to illustrate how mosquitoes stand or walk on water with only their tarsi in nearly horizontal contact with the water surface. Besides enhancing our understanding of mechanisms underlying "walking on water" by semi-aquatic insects, these investigations could provide inspiration for the biomimetic design of miniature robotics. © 2015 Author(s). Source


Li J.,Shandong University | Zhao M.,Shandong University | Zhao M.,China University of Petroleum - East China | Zheng L.,Shandong University
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2012

The wormlike micelles formed by surface active N-alkyl- N-methylpyrrolidinium bromide ionic liquids (ILs) have been investigated in aqueous solution. The typical rheological parameters and the viscoelastic properties of wormlike micelles were characterized by rheological measurements and cryogenic-transmission electron microscopy (cryo-TEM). The typical rheological parameters were further evaluated by Maxwell model and the viscoelastic properties were discussed based on the living polymer model. Cryo-TEM images confirmed the formation of wormlike micelles in aqueous solution. The effect of the hydrocarbon chain length of the ILs on the wormlike micelles formation was also studied. © 2011 Elsevier B.V. Source


Zhao M.,Shandong University | Zhao M.,China University of Petroleum - East China | Yuan J.,Shandong University | Zheng L.,Shandong University
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2012

The spontaneous formation of vesicles in an aqueous catanionic mixture, composed of a cationic surface active long-chain ionic liquid N-dodecyl-N-methylpyrrolidinium bromide (C 12MPB) and an anionic surfactant sodium dodecyl sulfate (SDS), is investigated. The phase behavior of catanionic system is studied and the phase diagram is mapped through visual observation and electrical conductivity measurement. The vesicles formed in the lamellar phase (L α) are characterized by transmission electron microscopy (TEM). The macroscopic properties of birefringent L α phase are investigated by rheological measurements. The hydrophobic and electrostatic interactions are regarded as the main driving forces for spontaneous formation of vesicles. © 2012 Elsevier B.V.. Source


Li Y.,Harbin Institute of Technology | Li Y.,China University of Petroleum - East China | Wang M.,Harbin Institute of Technology
Nonlinear Analysis: Real World Applications | Year: 2013

The paper is concerned with a diffusive prey-predator model subject to the homogeneous Neumann boundary condition, which models the trophic intersections of three levels. We will prove that under certain assumptions, even though the unique positive constant steady state is globally asymptotically stable for the dynamics with diffusion, the non-constant positive steady state can exist due to the emergence of cross-diffusion. We demonstrate that the cross-diffusion can create stationary pattern. Moreover, we treat the cross-diffusion parameter as a bifurcation parameter and discuss the existence of non-constant positive solutions to the system with cross-diffusion. © 2012 Elsevier Ltd. All rights reserved. Source


Jiang L.,China University of Petroleum - East China | Titmuss S.,University of Edinburgh | Klein J.,University of Oxford | Klein J.,Weizmann Institute of Science
Langmuir | Year: 2013

We used colloidal probe atomic force microscopy to measure the normal forces between the surface of a silica colloidal particle and a sparse layer of hyaluronan (hyaluronic acid, HA, MW ≈ 106 Da) covalently attached to a planar silica surface, both across pure water and following the addition of 1 mM MgCl2. It was found that in the absence of salt the HA layer repelled the colloidal silica surface during both approach and retraction. The addition of the MgCl2, however, changes the net force between the negatively charged HA layer and the opposing negatively charged silica surface from repulsion to adhesion. This interaction reversal is attributed to the bridging effect of the added Mg2+ ions. Our results provide first direct force data to support earlier simulation and predictions that such divalent cations could bridge between negative charges on opposing surfaces, leading to an overall reversal of force from repulsion to attraction. © 2013 American Chemical Society. Source


Li M.-C.,China University of Petroleum - East China | Fan S.-S.,South China University of Technology
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | Year: 2013

Based on the description of dissociation process of natural gas hydrate in a semi-infinite zone, a radial pseudo-stationary mathematical model of heat transfer was built with Stefan moving boundary, and accurate solution of temperature applied in dissociation zone and natural gas hydrate zone was calculated by using Paterson method of exponential integral function. In addition, the location of dissociation frontal brim of natural gas hydrate was determined by combining Deaton method with Clausius-Clapeyron equation for decomposition heat. Radial dissociation laws of natural gas hydrate were obtained through an example of a steady hydrate reservoir whose physical parameters are known: with the increasing of radial range, temperature of hydrate reservoir drops abruptly to 8.416°C (dissociation temperature) and further to 5.33°C (reservoir temperature), and the location of dissociation frontal brim changes slowly; besides, with the increase of time, the temperature rises sharply after increasing slowly from 5.33°C to 8.416°C, and after adequate days will reach 100°C (the injected hot water temperature); furthermore, radius of hydrate dissociation grows slowly, and after 150 days supposed dissociation temperature changes 27.3°C for 80~100°C and 49.3°C for 100~150°C. Source


Zhan K.,China University of Petroleum - East China | Hou C.,Harbin Institute of Technology
Optics Communications | Year: 2012

We analyze the existence and stability of gap solitons supported by optical lattices with self-focusing nonlinearity in biased centrosymmetric photorefractive crystals. It is shown that, in first finite bandgap, gap solitons are symmetric in transverse dimension, single humped, entirely positive and linearly stable, while these solitons are antisymmetric with similar profiles, the stable and unstable intervals of the gap solitons are intertwined in the second finite bandgap. © 2012 ElsevierB.V.Allrightsreserved. Source


Chen Y.-B.,China University of Petroleum - East China
Advanced Materials Research | Year: 2014

This paper is devoted to the analysis of frictional contact problems with large deformations and displacements between hyper-elastic body and rigid body. The material nonlinearity and contact nonlinearity are separated and, the geometrically nonlinear behavior is described by the total Lagrange formulation. The Coulomb friction law is employed to simulate the friction between rigid vessel and rubber by the use of augmented Lagrange approach with node-to-segment formulation. A formulation of finite element is taken in this paper to describe the frictional contact problem, which is solved by the Newton-Raphson iterative procedure. It is shown that the augmented Lagrange technique significantly avoids locking and over-constraining and provides optimal convergence rate. Finally, the numerical results show that the accuracy and efficiency of augmented Lagrange approach in modeling large deformation frictional contact problem. © (2014) Trans Tech Publications, Switzerland. Source


Bai B.,Missouri University of Science and Technology | Sun Y.,China University of Petroleum - East China | Liu L.,Missouri University of Science and Technology
Petroleum Exploration and Development | Year: 2016

With multiple techniques, the following measurements and analysis were made to characterize the Ordovician Utica shale samples: mineralogy, porosity, microstructure, and surface wettability etc. The test of mercury injection apparatus showed that the pore size of Utica shale is 15-200 nm. X-ray diffraction (XRD) mineralogy analysis and Energy-Dispersive X-ray Spectroscopy (EDS) indicated that in Utica shale non-clay minerals are dominated by calcite and quartz, while clay minerals by illite and chlorite. With the images from scanning electron microscope (SEM), the surface microstructure examination showed various types of pores exist in Utica shale, such as intragranular, intergranular, organic etc. And the pores in organic matter (kerogen) were found in nanometer size (10 to 50 nm). A three-dimensional tomography model and a geometry model of the pores space using FIB-SEM imaging tomography were reconstructed with 250 SEM images. It provides visual insights into the petrophysical properties of Utica shale. Finally, the wettability tests displayed that Utica shale has weak-water wet to intermediate wettability. © 2016 Research Institute of Petroleum Exploration & Development, PetroChina. Source


Lian Y.,China University of Petroleum - East China | Liu Y.,Yanbian University | Jiang T.,Yanbian University | Shu J.,Beijing Institute of Technology | And 2 more authors.
Journal of Physical Chemistry C | Year: 2010

We report for the first time the fabrication of the graphene oxide (GO)-Nafion actuators with carbon nanotubes (CNTs) as electrodes. The exfoliated GO was homogeneously dispersed in the Nafion matrix with doping level of 0.5-10 wt %. CNT electrodes on both sides of the membrane were made by dip-coating method; that is, the composites membranes were first emerged into the CNT-Nafion dimethylformamide (DMF) solution and then pulled out to dry. The as-prepared GO-Nafion actuators were tested in terms of conductivity, bulk and surface morphology, tip displacement, and blocked force. The results demonstrated that the electrochemical behavior of the polymer nanocomposite was significantly improved because of the efficient distribution of the high aspect ratio GO sheets, and the blocking force of the nanocomposite actuator with doping level 10 wt % is 4 times that of the virgin nafion, and the displacement is nearly 2 times that of nafion. © 2010 American Chemical Society. Source


Wang Y.,China University of Petroleum - East China | Xie M.,City University of Hong Kong
Procedia Engineering | Year: 2012

Fuzzy fault tree (FFT) can offer an efficient method of representing the fault causes and handling fuzzy information in the relationships among events. However, FFT cannot incorporate the evidence into the reasoning as Bayesian Network (BN). To overcome the disadvantage of FFT and BN, an approach of integrating FFT with BN is proposed in this paper. Firstly, the FFT technique of Takagi and Sugeno model that can handle uncertainties in the relationships among different events is introduced. Secondly, the translation rules of converting FFT into BN are presented. The integration algorithm is then demonstrated on an offshore fire case study. © 2012 The Authors. Published by Elsevier Ltd. Source


Zhou J.,Shandong University of Technology | Zhang Z.,Shandong University of Technology | Xing W.,China University of Petroleum - East China | Yu J.,Shandong University of Technology | And 3 more authors.
Electrochimica Acta | Year: 2015

In this work, nitrogen-doped hierarchical porous carbon materials (NHPCs) are prepared by a two-step method combined of a hard template process and KOH-activation treatment. Low cost and large-scale commercial nano-SiO2 are used as a hard template. The hierarchical porosity, structure and nitrogen-doped surface chemical properties are proved by a varies of means, such as scanning electron microscopy, transition electron microscopy, N2 sorption, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. When the prepared NHPCs materials are used as the electrode materials for supercapacitors in KOH electrolyte, they exhibit very high specific capacitance, good power capability and excellent cyclic stability. NHPC-800 carbon shows a high capacitance of 114.0 F g-1 at the current density of 40 A g-1, responding to a high energy and power densities of 4.0 Wh kg-1 and 10 000 W kg-1, and a very short drain time of 1.4 s. The excellent capacitive performance may be due to the synergistic effect of the hierarchical porosity, high effective surface area and heteroatom doping, resulting in both electrochemical double layer and Faradaic capacitance contributions. © 2014 Elsevier Ltd. All rights reserved. Source


Li Y.,China University of Petroleum - East China
Nonlinear Analysis: Real World Applications | Year: 2016

This paper is concerned with general models of Brusselator type subject to the homogeneous Neumann boundary condition. The existence of Hopf bifurcation for the ODE and PDE models is obtained. By the center manifold theory and the normal form method, the bifurcation direction and stability of bifurcating periodic solutions are established. Moreover, some numerical simulations are shown to support the analytical results. © 2015 Elsevier Ltd. Source


Kang Z.,China University of Petroleum - East China | Zi S.,Qingdao Jiaozhou Power Supply Company
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2013

As the regional distributed network of oil-field possessing the characteristics of heavy load, severe short of reactive power and large grid losses, a reactive power optimization method which is suitable for the oil-field regional network is proposed in this paper. The mathematical model of reactive power optimization was established which had comprehensively considered the economy and security of the system to make them constraint each other in the proposed method. The proposed optimization model was solved with the differential evolution algorithm, which had been merely mentioned in previous research of power system reactive power optimization. By using this algorithm, the optimization results are independent of the initial values and few controlled variables are neccessory. It is easy to find the global optimal solutions with the differential evolution. The results of the cases analysis and the compare of different optimization methods suggested that the proposed regional distributed network reactrive power optimization method be feasible and valid. Source


Sun L.,China University of Petroleum - East China | Chang N.,Colorstone Leakage Supervisory Technology Company
Journal of Loss Prevention in the Process Industries | Year: 2014

Leaks in pipelines can cause major incidents resulting in both human injuries and financial losses. Among the considerable leak detection and location methods, the Negative Pressure Wave (NPW) based method has been widely used in locating leaks in liquid pipelines. The NPW based method only monitors the pressure changes at two ends of a pipeline. But the pressure is apt to be fixed by the end equipment and the change of it induced by a small or slow leakage is too small to be detected, which limit the application of the NPW based method in these situations. This paper presents a novel leak location method based on integrated signal, which is a combination of the pressure and flow rate signals. The representation of the integrated signal is derived from the transient analysis of the leakage. For the change of the integrated signal induced by a leakage is larger than the pressure change and it is also unaffected by the end equipment, the proposed method can be used to detect and locate small or slow leakage in a pipeline and can also be used in pipelines which end pressures are fixed by some kinds of equipment. The validation of the proposed method also confirms its advantages. © 2014 Elsevier Ltd. Source


Wang Y.,China University of Petroleum - East China
Applied Mechanics and Materials | Year: 2013

As an emerging technology in the field of oil and gas well project, oil and gas well expansion pipe could maximally reduce the hole size decrease resulting from reduced catheter column of the wellbore, so as to achieve the purpose of saving costs. Meanwhile, this technology brings good news to Nerve well drilling in complicated geological condition and improvement of well structure. This article starts from the working principles of expansion pipe, and puts emphasis on the key technologies of expansion pipe and gives a detailed analysis of the application of expansion pipe technology. © (2013) Trans Tech Publications, Switzerland. Source


Gao W.-F.,Xidian University | Liu S.-Y.,Xidian University | Huang L.-L.,China University of Petroleum - East China
Applied Soft Computing Journal | Year: 2013

Artificial bee colony (ABC) algorithm is a relatively new optimization technique which has been shown to be competitive to other population-based algorithms. However, there is still an insufficiency in ABC regarding its solution search equation, which is good at exploration but poor at exploitation. To address this concerning issue, we first propose a modified search equation which is applied to generate a candidate solution in the onlookers phase to improve the search ability of ABC. Further, we use the Powell's method as a local search tool to enhance the exploitation of the algorithm. The new algorithm is tested on 22 unconstrained benchmark functions and 13 constrained benchmark functions, and are compared with some other ABCs and several state-of-the-art algorithms. The comparisons show that the proposed algorithm offers the highest solution quality, fastest global convergence, and strongest robustness among all the contenders on almost all test functions. © 2013 Elsevier B.V. All rights reserved. Source


Ying-Chun B.,China University of Petroleum - East China | Jun-Fei Q.,Beijing University of Technology
Asian Journal of Control | Year: 2015

This paper proposes a heuristic dynamic programming (HDP) scheme to simultaneously control the dissolved oxygen concentration and the nitrate level in wastewater treatment processes (WWTP). Unlike traditional HDP schemes, the optimal control values are calculated in an analytical way by the proposed HDP controller. It can reduce the learning burden of the HDP controller to a great extent. The system model and the evaluation index J are approximated by two echo state networks (ESNs). Gradient-based learning algorithms are employed to train both ESNs online, and the convergence of the training algorithm is investigated based on Lyapunov theory. The performance of the proposed ESN-based HDP (E-HDP) controller is tested and evaluated on a WWTP benchmark. Experimental results demonstrate that the proposed approach can achieve effective performance. ©2014 Chinese Automatic Control Society and Wiley Publishing Asia Pty Ltd. Source


Wang C.,China University of Petroleum - East China | Morgner H.,University of Leipzig
Physical Chemistry Chemical Physics | Year: 2014

In the present paper, we aim to investigate the dependence of surface tension on the surface properties and reveal the counter-ion effects on the adsorption of ionic surfactants on the solution surface. The surface tension, surface excess and surface concentration (defined as the amount of surfactant adsorbed in the surface phase divided by the surface area) of two anionic surfactants, namely dodecyl sulfate sodium and dodecyl sulfate caesium, dissolved in non-aqueous polar solvent formamide have been separately measured at 6 °C through independent experiments. Then, the correlation of surface tension with surface concentration and that of surface tension with surface excess is inspected in detail. It was found that there is a linear relationship between the surface tension and the surface concentration for the pure solutions of each surfactant, but their surface tension and surface excess cannot be correlated linearly. It is striking that the same surface tension-surface concentration linearity holds for two different surfactants, although they have apparently distinct counter-ions. Based on this finding, it is derived that the surface tension is decided by surface concentration of the surface active ions. After analyzing the surface structure, it is concluded that the counter-ions affect the surface tension indirectly through modifying the adsorption amount of the surface active ions in the surface layer. This journal is © the Partner Organisations 2014. Source


Tong D.,China University of Petroleum - East China
Acta Mechanica | Year: 2010

Exact solutions for the motions of a generalized Burgers' fluid due to longitudinal and torsional oscillations of a circular cylinder are obtained using Hankel transform and Laplace transform. These solutions are expressed as sum of steady-state and transient solutions. They describe the motion of the fluid for some time after its initiation. After that time, when the transients disappear, the motion is described by the steady-state solution which is periodic in time and independent of the initial conditions. Finally, by means of graphical illustrations, the velocity field is determined for sine and cosine combined oscillations of the boundary. © 2010 Springer-Verlag. Source


Liu J.L.,China University of Petroleum - East China
Acta Mechanica Sinica/Lixue Xuebao | Year: 2010

The stiction of a thin plate induced by the capillary force has attracted much attention in the broad range of applications. A novel method is presented to calculate the capillary adhesion problem of the plate through analytical method. The expressions of the surface energy, the strain energy and the total potential energy of the plate-substrate system have been analyzed and delineated. By means of continuum mechanics and the principle of minimum potential energy, the governing equation of the plate with an arbitrary shape and the corresponding transversality boundary condition due to the moving bound have been derived. Then the critical adhesion radius of the circular plate has been solved according to the supplementary transversality condition. Thus the deflections of the plates are analytically calculatedwith different critical adhesion radii. The results may be beneficial to the engineering application and themicro/nanomeasurement. © 2009 The Chinese Society of Theoretical and Applied Mechanics and Springer-Verlag GmbH. Source


Liu Y.,Petrochina | Bai B.,Missouri University of Science and Technology | Wang Y.,China University of Petroleum - East China
Oil and Gas Science and Technology | Year: 2010

China is the largest user of chemical-based conformance control treatments and a series of technologies have been successfully developed and deployed in recent years. This paper first shows the milestones of development and application of conformance control technologies in China. Then integrated conformance control technologies are reviewed followed by the lessons we have learned, and then a few major specific conformance control technologies are addressed, including tracer injection and channels explanation, potentiometric testing to identify areal sweep efficiency, Pressure Index (PI) decisionmaking technology to select well candidate, complementary decision-making technology to select well candidate and design application parameters, and major chemicals for in-depth fluid diversion technologies. In addition, this paper also describes the principles and applications of some promising technologies of combined chemical-based conformance treatment with other EOR/IOR process, including the combination technology of surfactant and water shutoff, profile control and mini-scale surfactant flooding, acid treatment and profile control treatment. Finally, this paper summarizes the problems and challenges faced by mature water flooded oilfields in China. Based on recent well tests, tracer testing and interpretation, and previous water control treatment experience, it appears that channels or high permeability streaks are common in mature water flooded oilfields. Some research directions and promising technologies are suggested. © 2010, IFP Energies nouvelles. Source


Sun J.,Northeast Normal University | Sun J.,China University of Petroleum - East China | Pei D.,Northeast Normal University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2014

The null surfaces of null curves on 3-null cone have the applications in the studying of horizon types. Via the pseudo-scalar product and Frenet equations, the differential geometry of null curves on 3-null cone is obtained. In the local sense, the curvature describes the contact of submanifolds with pseudo-spheres. We introduce the geometric properties of the curvatures and show the singularities of null surfaces, which are constructed over the null curves. © 2014 Elsevier B.V. Source


Zhang W.,Shandong University of Science and Technology | Zhao Y.,Shandong University of Science and Technology | Sheng L.,China University of Petroleum - East China
Automatica | Year: 2015

This paper discusses the stability for stochastic singular systems with state-dependent noise in both continuous-time and discrete-time cases. Firstly, the condition for the existence and uniqueness of the solution to stochastic singular systems is given. Based on this condition, the stochastic Itô singular system is transformed into a deterministic standard singular system by means of H-representation method. Secondly, new sufficient conditions for the stability of systems considered are derived in terms of strict linear matrix inequalities. Finally, an example is given to illustrate the effectiveness of the obtained theoretical results. © 2014 Elsevier Ltd. All rights reserved. Source


Song T.,China University of Petroleum - East China | Pan L.,Huazhong University of Science and Technology
Neurocomputing | Year: 2016

Spiking neural P systems, shortly called SN P systems, are a class of distributed and parallel neural-like computing models, inspired from the way of neurons spiking and communicating with each other by means of spikes. In this work, we propose a new variant of SN P systems, called SN P systems with request rules. In such a system, besides spiking and forgetting rules, a neuron can have request rules, with which the neuron can sense "stimulus" from the environment by receiving a certain number of spikes. We investigate the computation power of SN P systems with request rules. It is obtained that such systems are Turing universal, even with a small number of neurons. Specifically, (i) SN P systems with request rules having 4 neurons can compute any set of Turing computable natural numbers and (ii) with 47 neurons such systems can compute any Turing computable function. © 2016 Elsevier B.V. Source


He J.-H.,China University of Petroleum - East China
Petrochemical Equipment | Year: 2010

Practical safety valve check equipment in which an automatic clamping apparatus are applied has been developed. Its components and process are described. The designs of the automatic clamping apparatus are illustrated in detail and the related calculations are given. Source


Zhang J.,China University of Petroleum - East China
Nonlinear Analysis: Real World Applications | Year: 2016

In this paper, we study the Kirchhoff type problem with critical growth. By using the variational method, the existence and multiplicity of solutions are obtained. © 2015 Elsevier Ltd. Source


Cao D.,China University of Petroleum - East China
Geophysical Prospecting for Petroleum | Year: 2015

3D surface seismic data has the advantage of comprehensive exploration for the subsurface geology body relatively, while well logging curves present the reservoir and petrophysical information at the borehole location. It is a big challenge for the reservoir prediction and fluid identification because of the scale difference between surface seismic data and logging data. As to the upscaling of logging curve for petrophysical characteristics research at the seismic scale, the Backus equivalence averaging method is adapted to the upscaling of logging data in this paper. Besides the method of logging curves upscaling based on Backus equivalence averaging, the key parameters of slide sweeping time window, reference frequency and the resample thickness are discussed for the effects of the upscaling method. The petrophysical characteristics from logging curves before and after upscaling are analyzed and compared. The relation and the difference for the raw logging curves and upscaling results have been discussed. The petrophysical analysis conclusions under seismic scale is benefical to the prestack seismic inversion and reservoirs prediction based on the combination of seismic data and logging data. ©, 2015, Science Press. All right reserved. Source


Guo J.,CAS Academy of Mathematics and Systems Science | Zhang Q.,China University of Petroleum - East China | Gao X.-S.,CAS Academy of Mathematics and Systems Science
Journal of Systems Science and Complexity | Year: 2013

In this paper, a method of reducing the tracking