Time filter

Source Type

Dalian, China

Dalian University of Technology , colloquially known in Chinese as Dagong , is a public research university located in Dalian and Panjin, Liaoning province, People's Republic of China. DUT, previously renowned as one of the Big Four Institutes of Technology, is among China's top universities for engineering and technology. It is also one of the national key universities administered directly under the Ministry of Education of China. Wikipedia.

Lu X.-B.,Dalian University of Technology | Darensbourg D.J.,Texas A&M University
Chemical Society Reviews | Year: 2012

This comprehensive tutorial review focuses on well-defined cobalt complexes that serve as homogeneous catalysts for the production of polycarbonates and cyclic carbonates from the coupling of carbon dioxide and epoxides. Special considerations are given to the mechanistic pathways involved in these processes. © 2012 The Royal Society of Chemistry.

Li M.,Newcastle University | Li M.,Dalian University of Technology | Scott K.,Newcastle University
Electrochimica Acta | Year: 2010

Poly(tetrafluoroethylene) PTFE/PBI composite membranes doped with H3PO4 were fabricated to improve the performance of high temperature polymer electrolyte membrane fuel cells (HT-PEMFC). The composite membranes were fabricated by immobilising polybenzimidazole (PBI) solution into a hydrophobic porous PTFE membrane. The mechanical strength of the membrane was good exhibiting a maximum load of 35.19 MPa. After doping with the phosphoric acid, the composite membrane had a larger proton conductivity than that of PBI doped with phosphoric acid. The PTFE/PBI membrane conductivity was greater than 0.3 S cm-1 at a relative humidity 8.4% and temperature of 180 °C with a 300% H3PO4 doping level. Use of the membrane in a fuel cell with oxygen, at 1 bar overpressure gave a peak power density of 1.2 W cm-2 at cell voltages >0.4 V and current densities of 3.0 A cm-2. The PTFE/PBI/H3PO4 composite membrane did not exhibit significant degradation after 50 h of intermittent operation at 150 °C. These results indicate that the composite membrane is a promising material for vehicles driven by high temperature PEMFCs. © 2009 Elsevier Ltd.

Wang J.-B.,Shenyang Aerospace University | Wang M.-Z.,Dalian University of Technology | Ji P.,Hong Kong Polytechnic University
International Journal of Systems Science | Year: 2012

In this article, we consider a single machine scheduling problem with a time-dependent learning effect and deteriorating jobs. By the effects of time-dependent learning and deterioration, we mean that the job processing time is defined by a function of its starting time and total normal processing time of jobs in front of it in the sequence. The objective is to determine an optimal schedule so as to minimize the total completion time. This problem remains open for the case of -1

Xu L.,Dalian University of Technology | Xu L.,CAS Institute of Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

In this paper, a specific family of f(R) models that can produce the ΛCDM background expansion history is constrained by using the currently available geometric and dynamic probes. The scale dependence of the growth rate f(z,k) in this specific family of f(R) model is shown. Therefore to eliminate the scale dependence of fσ8(z) in theory, which usually is defined as the product of f(z,k) and σ8(z), we define fσ8(z)=dσ8(z)/dlna, which is obviously scale independent and reproduces the conventional definition in the standard ΛCDM cosmology. In doing so, under the assumption that future probes having the same best fit values as the current ten data points of fσ8(z), even having 20% error bars enlarged, we find a preliminary constraint fR0=-2.58-0.58+2.14×10-6 in 1σ regions. This indicates the great potential that redshift space distortions have in constraining modified gravity theories. We also discuss the nonlinear matter power spectrum based on different halo fit models. © 2015 American Physical Society.

Wang J.-B.,Shenyang Aerospace University | Wang J.-J.,Dalian University of Technology
Computers and Industrial Engineering | Year: 2011

In a manufacturing system workers are involved in doing the same job or activity repeatedly. Hence, the workers start learning more about the job or activity. Because of the learning, the time to complete the job or activity starts decreasing, which is known as "learning effect". In this paper, an exponential sum-of-actual-processing-time based learning effect is introduced into single-machine scheduling. By the exponential sum-of-actual-processing-time based learning effect, we mean that the processing time of a job is defined by an exponential function of the sum-of-the-actual- processing-time of the already processed jobs. Under the proposed learning model, we show that under a sufficient condition, the makespan minimization problem, the sum of the θth (θ > 0) power of completion times minimization problem, and some special cases of the total weighted completion time minimization problem and the maximum lateness minimization problem remain polynomially solvable. © 2010 Published by Elsevier Ltd. All rights reserved.

Liu C.,Nanotek Instruments, Inc. | Liu C.,Dalian University of Technology | Yu Z.,Angstron Materials, Inc | Neff D.,Nanotek Instruments, Inc. | And 2 more authors.
Nano Letters | Year: 2010

A supercapacitor with graphene-based electrodes was found to exhibit a specific energy density of 85.6 Wh/kg at room temperature and 136 Wh/kg at 80 °C (all based on the total electrode weight), measured at a current density of 1 A/g. These energy density values are comparable to that of the Ni metal hydride battery, but the supercapacitor can be charged or discharged in seconds or minutes. The key to success was the ability to make full utilization of the highest intrinsic surface capacitance and specific surface area of single-layer graphene by preparing curved graphene sheets that will not restack face-to-face. The curved morphology enables the formation of mesopores accessible to and wettable by environmentally benign ionic liquids capable of operating at a voltage >4 V. © 2010 American Chemical Society.

Liu T.,Dalian University of Technology | Liu T.,RWTH Aachen | Wang Y.,Beijing University of Chemical Technology
Automatica | Year: 2012

For industrial nonlinear batch processes that can be practically divided into a series of piecewise affine operating regions, a two-dimensional (2D) closed-loop iterative learning control (ILC) method is proposed for robust tracking of the set-point profile against cycle-to-cycle process uncertainties and load disturbances. Both state feedback and output feedback are considered for the control design, together with the process input and output constraints for implementation. Based on a 2D system description for the batch operation, a few synthetic performance and robust control objectives are proposed for developing the 2D ILC schemes, in combination with the 2D Lyapunov-Krasovskii functions that can guarantee monotonic state energy (or output error) decrease in both the time (during a cycle) and batch (from cycle to cycle) directions. Both the polyhedral and norm-bounded descriptions of process uncertainties are considered to derive the corresponding linear matrix inequality (LMI) conditions for the closed-loop ILC system robust stability. An important merit of these LMI conditions is that there are adjustable convergence indices prescribed for both the time and batch directions, and an adjustable robust control performance level for the closed-loop system. By specifying/optimizing these adjustable parameters to solve these LMI conditions, the 2D ILC controller can be explicitly derived for implementation. The application to a highly nonlinear continuous stirred tank reactor (CSTR) is shown to illustrate the effectiveness and merits of the proposed ILC method. © 2012 Elsevier Ltd. All rights reserved.

Cui Q.,Dalian Maritime University | Li Y.,Dalian University of Technology
Transportation Research Part D: Transport and Environment | Year: 2014

In this paper, transportation energy efficiency is newly defined and its inputs and outputs are obtained through literature review. Labor input, capital input and energy input are selected as the inputs, passenger turnover volume and freight turnover volume are defined as the outputs. A new model-three-stage virtual frontier DEA (three-stage virtual frontier Data Envelopment Analysis) is proposed to evaluate transportation energy efficiencies. The case of thirty Chinese PARs (provincial administrative regions) from 2003 to 2012 is applied to verify its rationality. In the three-stage virtual frontier DEA, the reference DMU (decision-making unit) set and the evaluated DMU set are two different sets so that it can distinguish the DEA efficient DMUs. And in the evaluating process, the reference DMU set remains unchanged to assure its results more reasonable than Super DEA model. The results show that transport structure and management measures have important impacts on transportation energy efficiency. © 2014 Elsevier Ltd.

Yang Y.-F.,Dalian University of Technology
Advances in Structural Engineering | Year: 2011

Recycled aggregate concrete-filled steel tube (RACFST) causes the recycled aggregate concrete (RAC) to be in a state of protection with the outer steel tube and thus the RAC is hardly affected by harmful environmental factors (e.g. wind, rain, moist). However, shrinkage and creep are the phenomena commonly associated with concrete-related structures, so studies on the behaviour of RACFST columns under long-term sustained loads are essential for the design of structures which include RACFST members. This study is an attempt to predict the time-dependent behaviour of RACFST columns by using the age-adjusted effective modulus method. The concrete shrinkage and creep in RACFST columns were studied experimentally, and the static bearing capacity of the tested specimens was also investigated. A theoretical model to account for the effects of concrete shrinkage and creep on RACFST columns under long-term sustained loading is developed, and comparisons of the results predicted using this model show good agreement with the test results. Formulae for the calculation of the bearing capacity of RACFST columns under long-term sustained loads are suggested.

Kang Z.,Dalian University of Technology | Luo Y.,Northwestern Polytechnical University | Li A.,University of Reims Champagne Ardenne
Structural Safety | Year: 2011

This paper investigates the formulation and numerical solution of reliability-based optimization of structures exhibiting grouped uncertain-but-bounded variations. Based on the multi-ellipsoid convex model description for grouped uncertain-but-bounded parameters, the mathematical definition of a non-probabilistic reliability index is presented for quantified measure of the safety margin. The optimal design is then formulated as a nested optimization problem. A method based on concerned performance is proposed for regularization of the reliability index constraints. The expensive computation of the non-probabilistic reliability index and its derivative is thus avoided. Numerical examples are given to illustrate the validity and efficiency of the present method. © 2011 Elsevier Ltd.

Xu L.,Dalian University of Technology | Xu L.,CAS Institute of Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

In a modified gravity theory, the propagation equation of gravitational waves will be presented in a nonstandard way. Therefore this tensor mode perturbation of time-space, as a complement to the scalar mode perturbation, provides a unique character distinguishing modified gravity from general relativity. To avoid the model-dependent issue, in this paper, we propose a parametrized modification to the propagation of gravitational waves. We show the effects on the angular power spectrum of cosmic microwave background radiation due to the parametrized modification and its degeneracy to the tensor mode power spectrum index nt and its running αt. Last, we report the current status on the detection of modified gravity through the currently available cosmic observations. Our results show no significant deviation to general relativity. © 2015 American Physical Society.

Li G.,Dalian University of Technology | Fahnestock L.A.,University of Illinois at Urbana - Champaign
Journal of Structural Engineering (United States) | Year: 2013

Steel concentrically braced frames (CBFs) are used widely as a seismic lateral force-resisting system. Although modern CBFs designed for high seismic regions have considerable ductility, CBFs in moderate seismic regions are expected to have limited ductility, even when designed using modern provisions. In addition, older CBFs in high seismic regions also are expected to have limited ductility. In these low-ductility systems, reserve capacity (i.e., secondary strength and stiffness) plays an important role in seismic collapse prevention. Thus, quantifying the impact of reserve capacity on earthquake response for low-ductility systems is critical. This paper presents research that used single-degree-of-freedom systems to represent low-ductility CBFs, where brace fracture causes a sudden loss of strength and stiffness. Postbrace fracture stability was studied by considering variations in reserve system strength and stiffness parameters. Performance was evaluated by considering local ductility demands on the reserve system and global drift demands. For the cases considered, the ductility capacity of the reserve system was typically a more critical constraint than global drift capacity. Reserve capacity is demonstrated to appreciably influence seismic collapse behavior, whereas primary system strength has a small influence. © 2013 American Society of Civil Engineers.

Gao X.-W.,Dalian University of Technology
Computer Methods in Applied Mechanics and Engineering | Year: 2010

In this paper, a robust method is presented for numerical evaluation of weakly, strongly, hyper- and super-singular boundary integrals, which exist in the Cauchy principal value sense in two- and three-dimensional problems. In this method, the singularities involved in integration kernels are analytically removed by expressing the non-singular parts of the integration kernels as power series in the local distance ρ of the intrinsic coordinate system. For three-dimensional boundary integrals, the radial integration method [1] is applied to transform the surface integral into a line integral over the contour of the surface and to remove various orders of singularities within the radial integrals. Some examples are provided to verify the correctness and robustness of the presented method. © 2010 Elsevier B.V.

Kang Z.,Dalian University of Technology | Luo Y.,Northwestern Polytechnical University
Structural and Multidisciplinary Optimization | Year: 2010

For structural systems exhibiting both probabilistic and bounded uncertainties, it may be suitable to describe these uncertainties with probability and convex set models respectively in the design optimization problem. Based on the probabilistic and multi-ellipsoid convex set hybrid model, this paper presents a mathematical definition of reliability index for measuring the safety of structures in presence of parameter or load uncertainties. The optimization problem incorporating such reliability constraints is then mathematically formulated. By using the performance measure approach, the optimization problem is reformulated into a more tractable one. Moreover, the nested double-loop optimization problem is transformed into an approximate single-loop minimization problem by considering the optimality conditions and linearization of the limit-state function, which further facilitates efficient solution of the design problem. Numerical examples demonstrate the validity of the proposed formulation as well as the efficiency of the presented numerical techniques. © 2009 Springer-Verlag.

Li S.,Dalian University of Technology
Biology of the cell / under the auspices of the European Cell Biology Organization | Year: 2012

Amplified in breast cancer 1 (AIB1) is a transcriptional coactivator of nuclear receptors and other transcription factors. It is required for animal growth and reproductive development, and has also been implicated in breast carcinogenesis. Although AIB1 is known to be covalently modified by SUMO-1, which serves to regulate its stability and transcriptional activity, the exact SUMO E3 ligase involved in its sumoylation has not been determined. In order to resolve this question, we investigated the interaction between AIB1 and different members of PIAS proteins (all are SUMO E3 ligases) through immunoprecipiation. Among the five different PIAS proteins, only PIAS1 co-immunoprecipitated with AIB1 in extract prepared from breast cancer cells (MCF-7). Over-expression of PIAS1 together with AIB1 in MCF-7 cells led to increased sumoylation of AIB1, resulting in repression of its transcriptional activity. In contrast, the PIAS1 mutant (C350S) lacking E3 ligase activity appeared to have no effect on the sumoylation of AIB1. Through sumoylation of AIB1, PIAS1 also promoted the stability of AIB1 and attenuated its interaction with estrogen receptor α (ERα), resulting in repression of the transactivation activity of ERα. In addition, MCF-7 cells co-transfected with wild-type PIAS1 and AIB1 showed about 40% reduction in cell growth, while cells co-transfected with wild-type PIAS1 and mutant AIB1 resistant to sumoylation showed about 34% increase in cell growth compared to cells transformed with wild-type AIB1 only. Taken together, these results suggested that PIAS1 may play a crucial role in the regulation of AIB1 transcriptional activity through sumoylation. Copyright © 2012 Soçiété Francaise des Microscopies and Société de Biologie Cellulaire de France.

Babel R.,McMaster University | Babel R.,Dalian University of Technology | Koshy P.,McMaster University | Weiss M.,RWTH Aachen
International Journal of Machine Tools and Manufacture | Year: 2013

Acoustic emission signals from interrupted machining operations exhibit spikes at workpiece entry and exit, which are particularly conspicuous in grinding. Although their occurrence has been widely reported, these spikes are yet to be clarified in terms of their origin or interpreted to yield useful process information. This paper hence reports on the analyses of time-averaged and raw acoustic emission signals from surface grinding, with reference to burr formation as well as dynamic and thermal effects, in order to elucidate this intriguing phenomenon. The transient spikes at the entry and exit are shown to be a consequence of the wheel establishing and losing contact with the work over the actual contact length, in terms of heat conduction and damping, which are reflected in characteristic frequency bands of the AE signal. The research is demonstrated to have consequently yielded a simple, non-destructive method for assessing the actual wheel-work contact length in grinding. © 2012 Elsevier Ltd.

Liu W.,Dalian University of Technology | Chen S.-E.,University of North Carolina at Charlotte
Structural Control and Health Monitoring | Year: 2013

Terrestrial 3D Light Detection and Ranging (LiDar) scanner has been suggested as a remote sensing technique for existing and newly constructed bridges. Using high resolution laser, 3D LiDar can populate a surficial area with millions of position data points. Bridge problems can benefit from LiDar scan, and current studies have found potential applications including damage detection, bridge clearance, and static deflection measurement. The technique is useful when accurate measurement of bridge geometry cannot be achieved by traditional survey technique, especially when site topography is prohibitive. However, resolution is still one of the main factors that limit the application of LiDar technology for advanced bridge monitoring. This paper discusses the reliability issues of such technique as well as the LiDar based bridge condition evaluation methodologies. Several experimental results are presented to establish the sensitivities for different assessments. Copyright © 2013 John Wiley & Sons, Ltd.

Li M.,Dalian University of Technology
Journal of Sound and Vibration | Year: 2015

Analytical solutions for the vibration of a beam with axial force subjected to generalized support motion are obtained in this paper. The finite element method (FEM) is introduced to validate the analytical solution obtained by an analytical approach. The dynamic responses of clamped-clamped, pinned-pinned and clamped-pinned beams with axial tension or compression are obtained via analytical approach and FEM. Comparing results show that the analytical approach is effective. The analytical analysis shows that the resonance will occur in general when the oscillatory frequency of transverse motion or rotation of any support end is equal to the natural frequency of the beam. Moreover, several cases in which the resonance disappears even if the frequencies of support excitations are equal to the natural frequencies of the beam are detected and are validated by the FEM solution. © 2014 Elsevier Ltd. All rights reserved.

Zhao N.,Dalian University of Technology | Yu F.R.,Carleton University | Leung V.C.M.,University of British Columbia
IEEE Wireless Communications | Year: 2015

IA is a promising technology for interference management in wireless networks. However, there are still some practical challenges. Signal to interference plus noise ratio (SINR) decrease is one of the key challenging issues due to the inherent property of IA and channel fading. Recent advances in OC, including multiuser diversity and antenna selection, can be applied in IA wireless networks to improve the SINR performance. In this article we review some existing research work on OC-based IA wireless networks. In addition, we propose a novel simultaneous wireless information and power transfer scheme based on OC in IA wireless networks. Simulation results are presented to show the performance comparison of these schemes. The methods to reduce the complexity of the OC-based IA algorithms are finally summarized. © 2002-2012 IEEE.

Liu Y.,Ocean University of China | Li Y.,Dalian University of Technology
Journal of Engineering Mathematics | Year: 2011

This study gives an alternative analytical solution for water-wave motion over an offshore submerged horizontal porous-plate breakwater in the context of linear potential theory. The matched-eigenfunction-expansions method is used to obtain the solution. The solution consists of a symmetric part and an antisymmetric part. The symmetric part is also the solution of wave reflection by a vertical solid wall with a submerged horizontal porous plate attached to it. In comparison with previous analytical solutions with respect to finite submerged horizontal porous plates, no complex water-wave dispersion relations are included in the present solution. Thus, the present solution is easier for numerical implementation. Numerical examples show that the convergence of the present solution is satisfactory. The results of the present solution also agree well with previous results by different analytical approaches, as well as previous numerical results by different boundary-element methods. The present solution can be easily extended to the case of multi-layer submerged horizontal porous plates, which may be more significant in practice for meeting different tide levels. © 2010 Springer Science+Business Media B.V.

Wang H.T.,Dalian Jiaotong University | Wang L.C.,Dalian University of Technology
Construction and Building Materials | Year: 2013

Since high strength of lightweight aggregate concrete leads to increased brittleness, fiber reinforcement should be considered for improving strength and ductility. Five groups of SFLWC specimens with different steel fiber volumes including 0.0%, 0.5%, 1.0%, 1.5% and 2.0% were tested to investigate the effect of steel fiber content on the static mechanical properties and the impact resistance of lightweight aggregate concrete. The static mechanical properties include the prismatic compressive strength, splitting tensile strength, first-crack flexural strength, flexural strength, and flexural toughness, etc. The impact resistance of SFLWC was obtained by a series of drop-weight tests, recommended by the ACI committee 544. The experimental results indicated that addition of steel fiber can greatly improve such mechanical properties as the splitting tensile strength, flexural strength, flexural toughness and impact resistance, but leads to a little effect on compressive strength. The test results also showed that a logarithmic relation exists between flexural toughness energy by means of the generated load-deflection curves from the flexural tests and the impact energy by means of drop-weight tests. Further more, the author suggests the feasible volume ratio of this kind of steel fiber is 1-1.5%. © 2012 Elsevier Ltd. All rights reserved.

Zhang L.,Dalian University of Technology | Yin Y.,University of Florida | Chen S.,University of Florida
Transportation Research Part C: Emerging Technologies | Year: 2013

This paper formulates a bi-objective optimization model to determine timing plans for coordinated traffic signals along arterials to minimize traffic delay and the risk associated with human exposure to traffic emissions. Based on a cell-transmission representation of traffic dynamics, a modal sensitive emission approach is used to estimate the tailpipe emission rate for each cell of a signalized arterial. A cell-based Gaussian plume air dispersion model is then employed to capture the dispersion of air pollutants and compute the roadside pollutant concentrations. A measure of mean excess exposure is further defined to represent the risk associated with human exposure to traffic pollutants under the wind uncertainty. A signal timing optimization model is formulated to optimize the cycle length, offsets, green splits and phase sequences to minimize the total system delay and the mean excess exposure simultaneously. The bi-objective optimization model is solved via a simulation-based genetic algorithm to find a set of Pareto optimal solutions. A numerical example is presented to demonstrate the model. © 2013 Elsevier Ltd.

Luo Y.,Northwestern Polytechnical University | Kang Z.,Dalian University of Technology
Computers and Structures | Year: 2012

This paper presents an efficient topology optimization strategy for seeking the optimal layout of continuum structures exhibiting asymmetrical strength behaviors in compression and tension. Based on the Drucker-Prager yield criterion and the power-law interpolation scheme for the material property, the optimization problem is formulated as to minimize the material volume under local stress constraints. The -relaxation of stress constraints is adopted to circumvent the stress singularity problem. For improving the computational efficiency, a grouped aggregation approach based on the Kreisselmeier- Steinhauser function is employed to reduce the number of constraints without much sacrificing the approximation accuracy of the stress constraints. In conjunction with the adjoint-variable sensitivity analysis, the minimization problem is solved by a gradient-based optimization algorithm. Numerical examples demonstrate the validity of the present optimization model as well as the efficiency of the proposed numerical techniques. Moreover, it is also revealed that the optimal design of a structure with pressure-dependent material may exhibit a considerable different topology from the one obtained with pressure-independent material model. © 2011 Elsevier Ltd. All rights reserved.

Chen S.-Y.,Dalian University of Technology
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2012

The theory of variable fuzzy sets is developed to variable fuzzy and clear sets referred to as variable sets. Study and establish the unity of opposite theorem that the clarity and fuzziness both change dynamic and get the research applied into the practice of optimal decision making for water resource system. Proposed the variable sets' unity of opposite theory and raised the principle and method of water resource system optimization decision making based on the variable sets. Given two examples of application, compared and analyzed with the Extenics and Fuzzy set pair analysis optimal method in detail. The result shows that the variable set is not only useful to optimizing assessment for the water resource system, but also for the other system, such as the water conservancy and hydropower, civil engineering system and many other fields' optimal decision making, having the broad application potential.

Sun H.,Dalian University of Technology
Nuclear Physics B | Year: 2014

In this work we study the constraints on the anomalous tqγ (q = u, c) couplings by photon-produced leading single top production and single top jet associated production through the main reactions pp→pγp→pt→pW(→ℓνℓ)b + X and pp→pγp→ptj→pW(→ℓνℓ)bj + X assuming a typical LHC multipurpose forward detectors in a model independent effective lagrangian approach. Our results show that: for the typical detector acceptance 0.0015 < ξ1 < 0.5, 0.1 < ξ2 < 0.5 and 0.0015 < ξ3 < 0.15 with a luminosity of 2fb -1, the lower bounds of κtqγ through leading single top channel (single top jet channel) are 0.0130 (0.0156), 0.0218 (0.0206) and 0.0133 (0.01655), respectively, corresponding to Br(t→qγ) ~ 3 × 10 -5. With a luminosity of 200fb -1, the lower bounds of κtqγ are 0.0041 (0.0048), 0.0069 (0.0064) and 0.0042 (0.0051), respectively, corresponding to Br(t→qγ) ~ 4 × 10 -6. We conclude that both channels can be used to detect such anomalous tqγ couplings and the detection sensitivity on κtqγ is obtained. © 2014 The Author.

Dou B.,Dalian University of Technology | Chen H.,CAS Institute of Engineering Thermophysics
Desalination | Year: 2011

In this study, the adsorption and photocatalytic reduction of toxic mercury(II) from aqueous solutions at different pH values were investigated with the synthesized TiO2 nanoparticles. The synthesized materials were tested and characterized by TEM, XRD and BET methods. The results showed that high purity anatase TiO2 nanoparticles with an average diameter of 9.10nm were produced by the acid catalyzed sol-gel method at 500°C, and the specific surface areas of synthesized TiO2 nanoparticles were in excess of 200m2g-1. The experimental results showed that the removal of mercury(II) in aqueous solutions were increased with an increase of pH in the range of 3.0-7.0, and the conversion of mercury(II) removal was more than 65% by TiO2 nanoparticles after 30min under UV illumination. Kinetics models of the adsorption and photocatalytic reduction were also studied by the experimental measurements. © 2010 Elsevier B.V.

Xu L.,Dalian University of Technology
Journal of Cosmology and Astroparticle Physics | Year: 2014

The normal branch of Dvali-Gabadadze-Porrati braneworld gravity with brane tension is confronted by the currently available cosmic observations from the geometrical and dynamical perspectives. On the geometrical side, the type Ia supernova as standard candle, the baryon acoustic oscillation as standard ruler and the cosmic microwave background measurement from the first released 15.5 months data were used to fix the background evolutions. On the dynamical side, the redshift space distortion data will be used to determine the evolution of the matter perturbation. Through a Markov chain Monte Carlo analysis, we found the dimensionless crossover scale Ωrc = 1/(4H2 0r2c) = 0.00183-0.00183 +0.000338 in a spatially flat normal branch of Dvali-Gabadadze- Porrati braneworld. This result suggests that the crossover scale rc should be around 12H-10 which is consistent with the previous result rc > 3H-10 and greater. It also implies that the five-dimensional gravity effect is weak to be observed in H-10 scale. © 2014 IOP Publishing Ltd and Sissa Medialab srl.

Zhao M.,University of Western Sydney | Cheng L.,University of Western Australia | Cheng L.,Dalian University of Technology
Physics of Fluids | Year: 2014

Vortex-induced vibration (VIV) of a rigid circular cylinder of finite length subject to uniform steady flow is investigated numerically. The study is focused on the effect of the free end on the response of the cylinder. The vibration of the cylinder is confined only in the cross-flow direction. Three-dimensional Navier-Stokes equations are solved by the Petrov-Galerkin finite element method and the equation of the motion is solved for the cylinder displacement. Simulations are conducted for a constant mass ratio of 2, a constant Reynolds number of 300 and cylinder length to diameter ratios of L/D = 1, 2, 5 10, and 20. It is found that the vortex shedding in the wake of a fixed cylinder is suppressed if the cylinder length is less than 2 cylinder diameters. However, if the cylinder is allowed to vibrate, VIV happens at L/D = 1 and 2 and the response amplitudes at these two cylinder lengths are comparable with that of a 2D-cylinder. The vortices that are shed from a short cylinder of L/D = 1 and 2 are found to be generated from the free-end of the cylinder and convected toward the top end of the cylinder by the upwash velocity. They are found to be nearly perpendicular to the cylinder span. The wake flow in a vibrating cylinder with L/D greater than 5 includes the vortex shedding flow at the top part of the cylinder and the end-induced vortex shedding near the free-end of the cylinder. The phase difference between the sectional lift coefficient and the vibration displacement near the free-end of the cylinder changes from 0° to 180° at higher reduced velocity than that near the top end. Strong variation of the flow along the cylinder span occurs at reduced velocities where the lift coefficient near the free-end and that near the top end are in anti-phase with each other. © 2014 AIP Publishing LLC.

Zhang Z.,University of Jinan | Han D.,University of Jinan | Wei S.,University of Jinan | Zhang Y.,University of Jinan | Zhang Y.,Dalian University of Technology
Journal of Catalysis | Year: 2010

Fe-doped CeO2 mixed oxides were studied for soot combustion with O2 under tight contact conditions. They show increased activity compared to that of pure CeO2 and Fe2O3. The optimum Fe content according to soot ignition temperatures is Fe/(Ce + Fe) = 10 at.%. However, on the basis of turnover frequencies, the samples with a Fe/(Ce + Fe) ratio between 5 and 20 at.% show similar activity. Characterization of the catalysts and a kinetic study show that the reaction proceeds via a redox mechanism. The active sites were determined to be composed of Fe-O-Ce species, and the active oxygen was quantified using isothermal anaerobic titrations with soot as a probe molecule. The redox property for the Fe-O-Ce species is much stronger than for the Ce-O-Ce species. The methodology for quantifying active redox sites can be extended to soot combustion on all similar oxide systems. © 2010 Elsevier Inc. All rights reserved.

Gu Y.,Hohai University | Chen W.,Hohai University | Chen W.,Dalian University of Technology | He X.-Q.,City University of Hong Kong
International Journal of Heat and Mass Transfer | Year: 2012

The singular boundary method (SBM) is a recent strong-form meshless boundary collocation method. Like the method of fundamental solutions (MFS), the SBM uses the fundamental solution of the governing differential equation of interest as the basis function and is mathematically simple, truly meshless, accurate, and easy-to-program. Unlike the MFS, the SBM, however, uses the concept of the origin intensity factor to isolate the singularity of the fundamental solutions and overcomes the fictitious boundary issue which has long perplexed the MFS. This study makes the first attempt to apply the SBM to steady-state heat conduction in three-dimensional (3D) anisotropic materials. Five benchmark numerical examples demonstrate that the SBM is accurate, convergent, stable, and computationally efficient in solving this kind of problems. © 2012 Elsevier Ltd. All rights reserved.

Wang H.-F.,Yanbian University | Wang H.-F.,Dalian University of Technology | Zhu A.-D.,Yanbian University | Zhang S.,Yanbian University
Optics Express | Year: 2013

We propose an efficient protocol for optimizing the physical implementation of three-qubit quantum error correction with spatially separated quantum dot spins via virtual-photon-induced process. In the protocol, each quantum dot is trapped in an individual cavity and each two cavities are connected by an optical fiber. We propose the optimal quantum circuits and describe the physical implementation for correcting both the bit flip and phase flip errors by applying a series of one-bit unitary rotation gates and two-bit quantum iSWAP gates that are produced by the long-range interaction between two distributed quantum dot spins mediated by the vacuum fields of the fiber and cavity. The protocol opens promising perspectives for long distance quantum communication and distributed quantum computation networks. © 2013 Optical Society of America.

Liu S.,Dalian University of Technology | Chen C.,Drexel University
Journal of the American Society for Information Science and Technology | Year: 2013

Although it is commonly expected that the citation context of a reference is likely to provide more detailed and direct information about the nature of a citation, few studies in the literature have specifically addressed the extent to which the information in different parts of a scientific publication differs. Do abstracts tend to use conceptually broader terms than sentences in a citation context in the body of a publication? In this article, we propose a method to analyze and compare latent topics in scientific publications, in particular, from abstracts of papers that cited a target reference and from sentences that cited the target reference. We conducted an experiment and applied topical modeling techniques to full-text papers in eight biomedicine journals. Topics derived from the two sources are compared in terms of their similarities and broad-narrow relationships defined based on information entropy. The results show that abstracts and citation contexts are characterized by distinct sets of topics with moderate overlaps. Furthermore, the results confirm that topics from abstracts of citing papers have broader terms than topics from citation contexts formed by citing sentences. The method and the findings could be used to enhance and extend the current methodologies for research evaluation and citation evaluation. © 2013 ASIS&T.

Chen J.,Dongbei University of Finance and Economics | Li C.-J.,Dalian University of Technology
Computers and Structures | Year: 2014

Couple stress/strain gradient elasticity has been developed to extend continuum plasticity to the micro- and nano-scale. In order to pass the C0 -1 enhanced patch test of a convergence condition, the element need to satisfy C0 and C1 continuity and possess the second-order accuracy simultaneously with nodal parameters including displacement and their first order derivatives. In this paper, a 24-DOF quadrilateral spline element for couple stress/strain gradient elasticity is proposed, which is a single displacement function. Numerical examples presented show that the proposed element is valid for both couple stress and strain gradient theories, and has high accuracy. © 2014 Elsevier Ltd. All rights reserved.

Gun H.,Usak University | Gao X.-W.,Dalian University of Technology
Engineering Analysis with Boundary Elements | Year: 2014

In this paper, a quadratic boundary element formulation for continuously non-homogeneous, isotropic and linear elastic functionally graded material contact problems with friction is presented. To evaluate domain related integrals, the radial integration method (RIM) based on the use of the approximating the normalized displacements in the domain integrals by a series of prescribed radial basis functions (RBF), leading a meshless scheme, is employed. An exponential variation with spatial coordinates is assumed for Young's modulus of the functionally graded materials (FGM), while Poisson's ratio is assumed to be constant. Under the contact conditions, including infinite friction, frictionless and Coulomb friction, different systems of equations for each body in contact are united. Numerical examples including non-confirming contact are given. © 2013 Elsevier Ltd.

Li L.,China Medical University at Heping | Xiaohui R.,Dalian University of Technology
Composite Structures | Year: 2010

Based on the higher-order global-local theories, a finite element model is proposed to study the bending behavior of stiffened laminated plates. The proposed model treats the embedded stiffeners as the part of laminated plate, so that the compatibility of displacements and stresses between the plate and the stiffeners can be automatically satisfied. Distributions of the displacements and stresses through the thickness of laminates were also given for the first time, which can serve as references for future investigations as such information is lacking in the published literature. In addition, the impact of the stiffeners on the bending response of the stiffened laminated plates is also studied in terms of the quantity, the collocation and the geometry of stiffeners. Numerical results showed that the higher-order global-local theories are more suitable for predicting the bending response of thick and moderately thick stiffened laminated plates compared to the first order theory commonly used in engineering. By varying the quantity, the collocation and the geometry of stiffeners, the stiffness and the strength of stiffened laminated plates can be remarkably improved. © 2010 Elsevier Ltd.

Feyen M.,Max-Planck-Institut fur Kohlenforschung | Weidenthaler C.,Max-Planck-Institut fur Kohlenforschung | Schuth F.,Max-Planck-Institut fur Kohlenforschung | Lu A.-H.,Dalian University of Technology
Chemistry of Materials | Year: 2010

In this study, we provide a simple and reproducible method for the preparation of highly active and recyclable colloidal acid catalysts. First, 16-heptadecenoic acid-functionalized magnetite nanoparticles were encapsulated in monodisperse cross-linked polymer spheres. This was achieved by emulsion copolymerization technique in an aqueous phase of styrene and divinylbenzene (DVB). Different ratios of styrene and DVB were used to tune the structural stability and surface morphology of the composites. With increase in DVB content, the surfaces of the colloidal composites become increasingly rougher. The obtained colloids were functionalized with sulfonic acid groups to obtain magnetically recyclable catalysts with H+ contents in the range of 2.2-2.5 mmol g-1 and surface areas of 45-120 m2 g -1. For the condensation reaction of benzaldehyde and ethylene glycol, magnetic acid catalyst prepared only from DVB precursor was found to be active and with high selectivity and long-term stability. © 2010 American Chemical Society.

Yang S.,East China Sea Environmental Monitoring Center | Yang F.,Dalian University of Technology
Journal of Hazardous Materials | Year: 2011

An intermittently aerated moving bed membrane bioreactor (MBMBR) was developed and crucial parameters affecting nitrogen removal from wastewater by simultaneous nitrification and denitrification via nitrite were investigated, without strict control of solids retention time. Changes in the microbiological community and distribution in the reactor were monitored simultaneously. The intermittent-aeration strategy proved effective in achieving nitrition and the chemical oxygen demand (COD) to total nitrogen (TN) ratio was an important factor affecting TN removal. In the MBMBR, the nitrite accumulation rate reached 79.4% and TN removal efficiency averaged at 87.8% with aeration 2. min/mix 4. min and an influent COD/TN ratio of 5. Batch tests indicated that under the intermittently aerated mode, nitrite-oxidizing bacteria (NOB) were not completely washed out from the reactor but NOB activity was inhibited. The intermittently aerated mode had no effect on the activities of ammonia-oxidizing bacteria. Fluorescence in situ hybridizations (FISH) results also suggested that NOBs remained within the system. © 2011 Elsevier B.V.

Leus K.,Ghent University | Liu Y.-Y.,Ghent University | Liu Y.-Y.,Dalian University of Technology | Van Der Voort P.,Ghent University
Catalysis Reviews - Science and Engineering | Year: 2014

Since the discovery of Metal Organic Frameworks (MOFs) in the early 1990s, the amount of new structures has grown exponentially. A MOF typically consists of inorganic nodes that are connected by organic linkers to form crystalline, highly porous structures. MOFs have attracted a lot of attention lately, as the versatile design of such materials holds promises of interesting applications in various fields. In this review, we will focus on the use of MOFs as heterogeneous oxidation catalysts. MOFs are very promising candidates to replace homogeneous catalysts by sustainable and stable heterogeneous catalysts. The catalytic active function can be either the active metal sites of the MOF itself or can be introduced as an extra functionality in the linker, a dopant or a "ship-in-a-bottle" complex. As the pore size, pore shape, and functionality of MOFs can be designed in numerous ways, shape selectivity, and even chiral selectivity can be created. In this article, we will present an overview on the state of the art of the use of MOFs as a heterogeneous catalyst in liquid phase oxidation reactions. © 2014 Taylor and Francis Group, LLC.

Zhou H.,Dalian University of Technology
Materials and Manufacturing Processes | Year: 2010

Ultraprecision grinding by a #6000 diamond grinding wheel on soft-brittle Cd0.96Zn0.04Te (111) crystals was conducted, and ultrasmooth machined surface was achieved. The ground surface of Cd 0.96Zn0.04Te (111) was compared with that of lapping and chemical mechanical polishing (CMP). The experimental results show that the surface roughness, Ra, and machining duration by ultraprecision grinding and CMP are 4.985nm, 1.478nm, and 35min, 135min, respectively, thus ultraprecision grinding exhibits high-efficiency and ultraprecision characters. The ground surface is smooth, uniform, microcrack and imbedding-free, while the machined surface by CMP appears free abrasive imbedding at local micro-area, leading to the decrease of surface integrity. Copyright © Taylor & Francis Group, LLC.

Zang W.,Fujian University of Technology | Wang Z.,Dalian University of Technology
Modern Tunnelling Technology | Year: 2014

As the tunnel body section is a relatively large proportion of the whole length of a tunnel, seismic risks cannot be ignored. A fuzzy comprehensive evaluation model (FCEM) was established to analyze the seismic risk to the body of a mountain tunnel. Based on data from 59 mountain tunnels damaged by the Wenchuan earthquake in the Sichuan province, 10 influential factors and their relationships to the earthquake were summarized: buried depth, construction situation, supporting structure and its intensity, section size and shape, seismic intensity, seismic wave direction, epicentral distance, tunnel length, fault and fractured weak zone, and surrounding rock. Furthermore, the analytic hierarchy process was adopted to calculate the weights of influential factors, and a fuzzy calculation was conducted using the trapezoidal and semantic membership function by fuzzy mathematics and weighted average method. FCEM was applied to the Longdongzi tunnel, with the results showing that the seismic risk to the Longdongzi tunnel body is extremely high.

Cui Q.,Dalian Maritime University | Li Y.,Dalian University of Technology
Journal of Air Transport Management | Year: 2015

In this paper, the energy efficiency of airlines has been studied with number of employees, capital stock and tons of aviation kerosene as the inputs and Revenue Ton Kilometers, Revenue Passenger Kilometers, total business income and CO2 emissions decrease index as the outputs. A new model, Virtual Frontier Benevolent DEA Cross Efficiency model (VFB-DEA), is proposed to calculate the energy efficiencies of 11 airlines from 2008 to 2012. Spearman correlation coefficient is applied to validate the applicability of the new model. The results indicate that capital efficiency is an important factor in driving energy efficiency, and the American financial crisis had a significant influence on the change in energy efficiency during this period. © 2015 Elsevier Ltd.

Fan W.,CAS Dalian Institute of Chemical Physics | Tan D.,Dalian University of Technology | Deng W.-Q.,CAS Dalian Institute of Chemical Physics
ChemPhysChem | Year: 2012

A series of metal-free acene-modified triphenylamine dyes (benzene to pentacene, denoted as TPA-AC1 to TPA-AC5) are investigated as organic sensitizers for application in dye-sensitized solar cells (DSSCs). A combination of density functional theory (DFT), density functional tight-binding (DFTB), and time-dependent DFT (TDDFT) approaches is employed. The effects of acene units on the spectra and electrochemical properties of the acene-modified TPA organic dyes are demonstrated. The dye/(TiO 2) 46 anatase nanoparticle systems are also simulated to show the electronic structures at the interface. The results show that from TPA-AC1 to TPA-AC5 with increasing sizes of the acenes, the absorption and fluorescence spectra are systematically broadened and red-shifted, but the oscillator strength and electron injection properties are reduced. The molecular orbital contributions show increasing localization on the bridging acene units from TPA-AC1 to TPA-AC5. From the theoretical examination of some key parameters including free enthalpy related to the electron injection, light-harvesting efficiency, and the shift of semiconductor conduction band, TPA-AC3 with an anthracene moiety demonstrates a balance of the above crucial factors. TPA-AC3 is expected to be a promising dye with desirable energetic and spectroscopic parameters in the DSSC field, which is consistent with recent experimental work. This study is expected to deepen our understanding of TPA-based organic dyes and assist the molecular design of new metal-free dyes for the further optimization of DSSCs. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Guo K.,Liaoning University | Li W.,Dalian University of Technology
Information Sciences | Year: 2012

Converting hybrid data in multiple attribute decision making (MADM) under uncertainty into intuitionistic fuzzy values (IFVs) is significant because the flexibility in handling vagueness or uncertainty of the latter can avoid the loss and distortion of the original decision information and thus guarantee the mildness of fuzzy MADM and the reliability of the final decision results. In this paper, we develop an attitudinal-based method for constructing intuitionistic fuzzy information according to the attribute values expressed in different data types in hybrid MADM. By introducing a basic unit-interval monotonic (BUM) function Q, we extract the attitudinal character from a person's information about his/her decision attitude, and formalize the person's subjective opinions against alternatives as IFVs based on the expected attribute values associated with attitude Q, thus transforming a hybrid decision matrix, with full consideration of a person's attitude, into an intuitionistic fuzzy decision matrix. The intuitionistic fuzzy aggregation operators are then used to aggregate the intuitionistic fuzzy attribute values of each alternative and a new approach is employed to rank these intuitionistic fuzzy alternatives based on the amount of information and its reliability. Finally, an example is provided to illustrate the proposed approach and to examine its feasibility and validity. © 2012 Published by Elsevier Inc. All rights reserved.

Yang Y.-F.,Dalian University of Technology | Han L.-H.,Tsinghua University
Thin-Walled Structures | Year: 2011

This paper investigates the behaviour of concrete filled steel tubular (CFST) stub columns subjected to eccentric partial compression. Twenty-eight specimens were tested and presented. The main parameters in test program include: (1) section type: circular, square and rectangular; (2) load eccentricity ratio (including uniaxial and biaxial loading): from 0 to 0.4; and (3) shape of the loading bearing plate (BP): circular, square, strip and rectangular. The test results indicated that, similar to the corresponding fully loaded CFST stub columns under eccentric loading, CFST stub columns under eccentric partial compression have generally reasonable bearing capacity and favorable ductility. A finite element analysis (FEA) model for CFST stub columns under eccentric partial compression is developed and the predicted performances are validated through measured results. The FEA model is then used to investigate the mechanisms of such composite columns further. © 2010 Elsevier Ltd. All rights reserved.

Guan B.-O.,Jinan University | Wang S.-N.,Dalian University of Technology
IEEE Photonics Technology Letters | Year: 2010

A novel fiber-optic current sensor based on a dual-polarization fiber grating laser is proposed and experimentally demonstrated. A permanent magnet exerts transversal force to the dual-polarization fiber grating laser due to the action of a magnetic field produced by an electric current. The transversal force modulates the fiber birefringence and, therefore, the beat frequency between the two polarization modes from the fiber grating laser. The sensor is capable of measuring both dc and ac current, and has advantages of ease of interrogation, absolute frequency encoding, and capability to multiplex a number of sensors on a single fiber. © 2010 IEEE.

Li X.,Shenyang Ligong University | Yang T.,Shenyang Ligong University | Lin J.,Dalian University of Technology
Journal of Biomedical Optics | Year: 2012

Surface-enhanced Raman spectroscopy (SERS) has been shown to be able to detect low-concentration biofluids. Saliva SERS readings of 21 lung cancer patients and 20 normal people were measured and differentiated. Most of the Raman peak intensities decrease for lung cancer patients compared with that of normal people. Those peaks were assigned to proteins and nucleic acids, which indicate a corresponding decrease of those substances in saliva. Principal component analysis (PCA) and linear discriminant analysis (LDA) were used to reduce and discriminate between the two groups of data, and the study resulted in accuracy, sensitivity, and specificity being 80%, 78%, and 83%, respectively. In conclusion, SERS of saliva showed the ability to predict lung cancer in Our experiment. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

Wang Y.-E.,Northeastern University China | Sun X.-M.,Dalian University of Technology | Wang Z.,University of Alberta | Zhao J.,Northeastern University China
Automatica | Year: 2014

This paper studies the stability issue for switched nonlinear systems with input delay and disturbance. It is assumed that for the nominal system an exponential stabilizing controller is predesigned such that the switched system is stable under a certain switching signal, and a piecewise Lyapunov function for the corresponding closed-loop system is known. However, in the presence of input delay and disturbance, the system may be unstable under the same switching signal. For this case, a new Lyapunov-Krasovskii functional is firstly constructed based on the known Lyapunov function. Then, by employing this new functional, a new switching signal satisfying the new average dwell time conditions is constructed to guarantee the input-to-state stability of the system under a certain delay bound. The bound on the average dwell time is closely related to the bound on the input delay. Finally, numerical examples are given to illustrate the effectiveness of the proposed theory. © 2014 Elsevier Ltd. All rights reserved.

Lin K.,Dalian University of Technology | Chen M.,Huazhong University of Science and Technology | Zeadally S.,University of the District of Columbia | Rodrigues J.J.P.C.,University of Beira Interior
Future Generation Computer Systems | Year: 2012

For Wireless Sensor Networks (WSNs), an unbalanced energy consumption will decrease the lifetime of network. In this paper, we leverage mobile agent technology to investigate the problem of how to balance the energy consumption during data collection in WSNs. We first demonstrate that for a sensor network with uniform node distribution and constant data reporting, balancing the energy of the whole network cannot be realized when the distribution of data among sensor nodes is unbalanced. We design a method to mitigate the uneven energy dissipation problem by controlling the mobility of agents, which is achieved by an energy prediction strategy to find their positions. Finally, we propose energy balancing cluster routing based on a mobile agent (EBMA) for WSNs. To obtain better performance, the cluster structure is formed based on cellular topology taking into consideration the energy balancing of inter-cluster and intra-cluster environments. Extensive simulation experiments are carried out to evaluate EBMA with several performance criteria. Our simulation results show that EBMA can effectively balance energy consumption and perform high efficiency in large-scale network deployment. © 2011 Elsevier B.V. All rights reserved.

Lv W.,CAS Dalian Institute of Chemical Physics | Chen M.,Dalian University of Technology | Wu R.,CAS Dalian Institute of Chemical Physics
Soft Matter | Year: 2013

Graphene nanopore based sensor devices have shown great potential for the detection of DNA. To understand the fundamental aspects of DNA translocation through a graphene nanopore, in this work, molecular dynamics (MD) simulations and potential of mean force (PMF) calculations were carried out to investigate the impact of the number of graphene layers of small nanopores (2-3 nm) on DNA translocation. It was observed that the ionic conductance was sensitive to the number of graphene layers of open-nanopores, and the probability of DNA translocation through graphene nanopores was related to the thickness of the graphene nanopores. MD simulations showed that DNA translocation time was most sensitive to the thickness of graphene nanopores of 2.4 nm aperture, and the observed free energy barrier of PMFs and the profile change revealed the increased retardation of DNA translocation through bilayer graphene nanopores as compared to that through monolayer graphene nanopores. This journal is © 2013 The Royal Society of Chemistry.

Huang Z.,Nanyang Technological University | Li Y.,Dalian University of Technology | Liu Y.,Ocean University of China
Ocean Engineering | Year: 2011

This paper reviews recent progress in the study of perforated/slotted breakwaters, with an emphasis on two main groups of such breakwaters: (1) perforated/slotted breakwaters with impermeable back walls, and (2) perforated/slotted breakwaters without a back-wall. The methods commonly used to simulate the interactions between such structures and various linear/nonlinear waves are summarized. The transmission and reflection characteristics of perforated/slotted breakwaters in these two groups are reviewed extensively. Several methods for calculating wave forces on perforated caissons are also reviewed. Some recent works published in Chinese journals, which are generally not well-known to non-Chinese researchers, are reviewed with a hope that these works can be beneficial to other researchers working in this area. © 2011 Elsevier Ltd. All rights reserved.

Duan L.,KTH Royal Institute of Technology | Tong L.,KTH Royal Institute of Technology | Xu Y.,KTH Royal Institute of Technology | Sun L.,KTH Royal Institute of Technology | Sun L.,Dalian University of Technology
Energy and Environmental Science | Year: 2011

This perspective article reports the most significant advances in the field of water oxidation - from molecular water oxidation catalysts (WOCs) to photoelectrochemical cells. Different series of catalysts that can be applied in visible light-driven water oxidation catalysis are discussed in details and several key aspects of their catalytic mechanisms are introduced. In order to construct a water oxidation electrode from molecular catalysts, proper immobilization methods have to be employed. Herein, we present one section about how to attach catalysts onto an electrode/material surface. Finally, the state of the art photoelectrochemical cells that achieve visible light-driven water splitting are described. © 2011 The Royal Society of Chemistry.

Uchaker E.,University of Washington | Cao G.,University of Washington | Cao G.,CAS Beijing Institute of Nanoenergy and Nanosystems | Cao G.,Dalian University of Technology
Nano Today | Year: 2014

Lithium-ion batteries are a well-established technology that has seen gains in performance based on materials chemistry over the past two decades. Although there are many material selections available when assembling such a device, the fundamental design and structure remains the same - two electrodes of different potential separated by an intermediary electrolyte. Despite recent advancements with electrode materials, considerable improvements in energy density and stability are still necessary in order to achieve energy storage parity. The design of structurally oriented nanoparticles can circumvent the thermodynamic instability, undesired side reactions, high processing costs, and potential nano-toxicity effects associated with nanoparticle synthesis, processing, and use. A great deal of recent efforts have focused on the formation and understanding of ordered nanoparticle superstructures with a vast range of architectures; in particular, crystallographically oriented nanoparticle superstructures, or mesocrystals. Mesocrystals can be delineated by their high degree of crystallinity, porosity, and nanoparticle subunit alignment along a crystallographic register. Given their unique combination of nanoparticle properties and order over a microscopic size regime, mesocrystals have strong potential as active materials for lithium-ion battery electrodes. Such assemblies would possess the structural and chemical stability of microsized electrodes while exploiting the beneficial properties associated with nanosized electrodes and their large reactive surface area. © 2015 Elsevier B.V. All rights reserved.

Li J.,Beijing Normal University | Deng G.,Northeast Dianli University | Li H.,Dalian University of Technology | Zeng W.,Beijing Normal University
Information Sciences | Year: 2012

In this paper, we introduce an axiomatic definition of the similarity measure of intuitionistic fuzzy sets (IFS) that differs from the definition of Li [15]. The relationship between the similarity measure and the entropy of IFS is investigated in detail. Six theorems on how the similarity measure could be transformed into the entropy for IFS and vice versa are proposed based on their axiomatic definitions. Some formulas have been proposed to calculate the similarity measure and the entropy of IFS. Finally, sufficient conditions to transform the similarity measures to the entropy for IFS and vice versa are given. © 2011 Elsevier Inc. All rights reserved.

Huang L.,Dalian University of Technology | Cheng S.,Zhejiang University | Chen G.,Hong Kong University of Science and Technology
Journal of Chemical Technology and Biotechnology | Year: 2011

Recalcitrant wastes including dyes, pesticides, explosives, heavy metals, polyalcohols, furan derivatives and phenolic substances, are of special concern owing to their recalcitrance and persistence in the environment. Bioelectrochemical systems (BESs) including microbial fuel cells (MFCs) and microbial electrolysis cells (MECs), integrate three important wastewater treatment options, namely, biological treatment, electrolytic dissociation and electrochemical oxidation/reduction, and are regarded as a new sustainable and effective strategy for treatment of these wastes. The simultaneous and cooperative roles of these multiple units running in parallel in BESs contribute to the efficiency of recalcitrant waste treatment, while substrate metabolism is considered to be a key step triggering different unit operations. An up-to-date review is provided on recent research and development in BESs-based recalcitrant wastes treatment. MFCs and MECs, as two types of BESs, are summarized in terms of treatment efficiency, recalcitrant substance metabolic pathway and microorganism diversity after a brief introduction to the electrochemical process for recalcitrant waste treatment. The scientific and technical challenges that have yet to be faced in the future are also discussed. © 2010 Society of Chemical Industry.

Cao T.,Dalian University of Technology | Simpson R.E.,Singapore University of Technology and Design | Cryan M.J.,University of Bristol
Journal of the Optical Society of America B: Optical Physics | Year: 2013

The tunable optical response of elliptical nanohole arrays penetrating through metal-phase change material-metal (Au - Ge2Sb 1Te4 - Au) films is numerically investigated using the finite difference time domain method in the mid-infrared spectral region. The influence of amorphous and crystalline structural states of Ge 2Sb1Te4 on the effective optical parameters of the structure is analyzed. Switching between these states provides a large wavelength shift of the structure's effective optical parameters. © 2013 Optical Society of America.

Hong L.J.,Hong Kong University of Science and Technology | Yang Y.,University of California at Irvine | Zhang L.,Dalian University of Technology
Operations Research | Year: 2011

When there is parameter uncertainty in the constraints of a convex optimization problem, it is natural to formulate the problem as a joint chance constrained program (JCCP), which requires that all constraints be satisfied simultaneously with a given large probability. In this paper, we propose to solve the JCCP by a sequence of convex approximations. We show that the solutions of the sequence of approximations converge to a Karush-Kuhn-Tucker (KKT) point of the JCCP under a certain asymptotic regime. Furthermore, we propose to use a gradient-based Monte Carlo method to solve the sequence of convex approximations. © 2011 INFORMS.

Wang J.-B.,Shenyang Aerospace University | Wang M.-Z.,Dalian University of Technology
Computers and Mathematics with Applications | Year: 2010

In this paper, we consider the problem of simultaneous determination of optimal due dates and optimal schedule for the single machine problem with multiple common due dates. The penalty for a job is assumed to be a linear function of the due date and the earliness/tardiness for the job. The objective function is to minimize the total penalty for all jobs. We show that with the introduction of learning to job processing times the problem remains polynomially solvable for a given number of multiple common due dates. © 2010 Elsevier Ltd. All rights reserved.

Wang Y.,Dalian University of Technology
Mathematical and Computer Modelling | Year: 2010

This paper concerns the existence of antiperiodic solution for the linear mild (strict) dissipative evolution equation. A Yoshizawa type theorem is proved by the modular degree theorem. Further, application to the semilinear mild (strict) dissipative evolution equation is also given. © 2009 Elsevier Ltd. All rights reserved.

Liu S.,Dalian University of Technology | Chen C.,Drexel University
Scientometrics | Year: 2012

Traditional co-citation analysis has not taken the proximity of co-cited references into account. As long as two references are cited by the same article, they are retreated equally regardless the distance between where citations appear in the article. Little is known about what additional insights into citation and co-citation behaviours one might gain from studying distributions of co-citation in terms of such proximity. How are citations distributed in an article? What insights does the proximity of co-citation provide? In this article, the proximity of a pair of co-cited reference is defined as the nearest instance of the co-citation relation in text. We investigate the proximity of co-citation in full text of scientific publications at four levels, namely, the sentence level, the paragraph level, the section level, and the article level. We conducted four studies of co-citation patterns in the full text of articles published in 22 open access journals from BioMed Central. First, we compared the distributions of co-citation instances at four proximity levels in journal articles to the traditional article-level co-citation counts. Second, we studied the distributions of co-citations of various proximities across organizational sections in articles. Third, the distribution of co-citation proximity in different co-citation frequency groups is investigated. Fourth, we identified the occurrences of co-citations at different proximity levels with reference to the corresponding traditional co-citation network. The results show that (1) the majority of co-citations are loosely coupled at the article level, (2) a higher proportion of sentence-level co-citations is found in high co-citation frequencies than in low co-citation frequencies, (3) tightly coupled sentence-level co-citations not only preserve the essential structure of the corresponding traditional co-citation network but also form a much smaller subset of the entire co-citation instances typically considered by traditional co-citation analysis. Implications for improving our understanding of underlying factors concerning co-citations and developing more efficient co-citation analysis methods are discussed. © 2011 Akadémiai Kiadó, Budapest, Hungary.

Vopson M.M.,University of Portsmouth | Zhou D.,Dalian University of Technology | Caruntu G.,Central Michigan University
Applied Physics Letters | Year: 2015

The multicaloric effect was theoretically proposed in 2012 and, despite numerous follow up studies, the effect still awaits experimental confirmation. The main limitation is the fact that the multicaloric effect is only observed at a temperature equal to the transition temperature of the magnetic and electric phases coexisting within a multiferroic (MF) (i.e., T ≈Tc m ≈Tc e). Such condition is hard to fulfill in single phase MFs and a solution is to develop suitable composite MF materials. Here, we examine the multicaloric effect in a bi-layer laminated composite MF in order to determine the optimal design parameters for best caloric response. We show that magnetically induced multicaloric effect requires magnetic component of heat capacity smaller than that of the electric phase, while the layer thickness of the magnetic phase must be at least 5 times the thickness of the electric phase. The electrically induced multicaloric effect requires the magnetic layer to be 10% of the electric phase thickness, while its heat capacity must be larger than that of the electric phase. These selection rules are generally applicable to bulk as well as thin film MF composites for optimal multicaloric effect. © 2015 AIP Publishing LLC.

Wang Z.,Dalian University of Technology
International Journal of Information Technology and Decision Making | Year: 2012

The collaborative innovation of industry, academia, and government is an effective way to enhance the innovative task and Triple helix approach can be used for its investigation. Bilateral relations can be expanded into triadic relationships and the complex dynamic process will produce a wide range of possible evolutionary trajectories. The essential feature of innovation is knowledge integration and creation. From different dimensions the knowledge will be integrated at knowledge-flow level and organizational level. In this paper, a self-organizing model of knowledge integration in collaborative innovation and its working processes including the nucleation and autopoiesis processes are introduced. Problem about degree of knowledge integration in collaborative innovation is discussed and a new comprehensive categorization method is suggested. Finally a case study is described. © 2012 World Scientific Publishing Company.

Wang L.,Dalian University of Technology | Ueda T.,Hokkaido University
Ocean Engineering | Year: 2011

Water penetration into concrete by capillary absorption plays a very important role in the ingress of contaminative substances when the structures are built in aggressive environments. In the present paper the lattice network model is proposed based on the unsaturated flow theory to predict the water penetration into concrete. On the mesocale level, concrete is treated as a three-phase composite. By means of the Voronoi diagram meshing strategy, the lattice network model of concrete with different types of lattice elements is developed. The corresponding transport properties are assigned to the lattice elements in the network falling in different phases. As a result, the lattice elements are idealized as conductive "pipes" in which uni-directional flow can be realized between the two nodes of the elements. Parameters in the lattice network model, such as the sorptivity and porosity of the mortar and the ITZs are quantitatively determined. With help of the approach, the water content distribution within a concrete sample after any elapsed time, especially the penetration depth of water frontier, can be easily predicted. The cumulative water absorption calculated by the lattice network model is shown to be well agreed with the experimental results. © 2011 Elsevier Ltd.

Zhang X.,Dalian University of Technology | Xu S.,Zhejiang University
Engineering Fracture Mechanics | Year: 2011

The current paper presents a comprehensive comparison of double-K fracture toughness parameters of concrete evaluated using experimental method and four existing analytical methods. Fracture tests were carried out on compact tension wedge splitting specimens with various depths varying from 200. mm up to 1000. mm. In the analytical calculation, depending on the relationship between critical crack tip opening displacement and the abscissa value of turning point on bilinear softening curve, two different distributions of cohesive stress are considered along crack extension. Results show that four available analytical calculations yield almost the same values of double-K fracture toughness parameters and agree well with those obtained from the experiment, which confirms the consistency of five approaches. Size effect was discussed, including unstable fracture toughness, initiation fracture toughness, critical effective crack length, the length of critical fracture process zone and critical crack tip opening displacement. © 2011 Elsevier Ltd.

Liang X.J.,Dalian University of Technology
BMC bioinformatics | Year: 2012

Identifying gene regulatory network (GRN) from time course gene expression data has attracted more and more attentions. Due to the computational complexity, most approaches for GRN reconstruction are limited on a small number of genes and low connectivity of the underlying networks. These approaches can only identify a single network for a given set of genes. However, for a large-scale gene network, there might exist multiple potential sub-networks, in which genes are only functionally related to others in the sub-networks. We propose the network and community identification (NCI) method for identifying multiple subnetworks from gene expression data by incorporating community structure information into GRN inference. The proposed algorithm iteratively solves two optimization problems, and can promisingly be applied to large-scale GRNs. Furthermore, we present the efficient Block PCA method for searching communities in GRNs. The NCI method is effective in identifying multiple subnetworks in a large-scale GRN. With the splitting algorithm, the Block PCA method shows a promosing attempt for exploring communities in a large-scale GRN.

Zhang D.,Tongji University | Li J.,Tongji University | Wang Q.,Tongji University | Wu Q.,Tongji University | Wu Q.,Dalian University of Technology
Journal of Materials Chemistry A | Year: 2013

Efficient photocatalytic nanocrystals with high-ratio exposure of active facets have aroused a great number of research interests in recent years. However, most preparations of such materials need the addition of special capping agents (like surfactants) or harsh reaction conditions (such as hydrothermal reactions). In this work, a controllable synthesis of BiOBr nanosheets with a thickness from 9 nm to 32 nm was easily achieved in a hydrolysis system through adjusting temperature and solvent, without adding any surfactant or capping agents. As the thickness of the nanosheets decreases from 32 nm to 9 nm, the ratio of exposed {001} facets, the active photocatalysis facets in BiOBr crystals, increases from 83% to 94%, along with an increased photocatalytic efficiency over rhodamine B (RhB) under visible-light. Various methods such as SEM, TEM, AFM, DRS and Raman spectroscopy were used to fully characterize the as-obtained BiOBr nanosheets. More importantly, the obtained BiOBr nanosheets exhibit a selective visible-light photocatalytic behavior as the activity over RhB is much higher than that over Methyl Orange (MO) or Methylene Blue (MB). This phenomenon was studied with in situ electron paramagnetic resonance (EPR) measurements and the potential mechanism was explored. © 2013 The Royal Society of Chemistry.

Nian F.,Lanzhou University of Technology | Wang X.,Dalian University of Technology
Chaos | Year: 2011

In this paper, pinning synchronization on directed network was considered. By analyzing, some general synchronization criteria on directed network were established. And then, we verified it on directed globally coupled network, directed scale-free network, and directed small-world network, respectively. The pinning nodes were selected, respectively, according to order of in-degrees and out-degrees. Through comparing and analyzing simulations, the optimal pinning scheme was found, and a practical principle was induced finally. © 2011 American Institute of Physics.

Pacheco-Torgal F.,University of Minho | Ding Y.,Dalian University of Technology | Jalali S.,University of Minho
Construction and Building Materials | Year: 2012

The volume of polymeric wastes like tyre rubber and polyethylene terephthalate bottles (PET) is increasing at a fast rate. An estimated 1000 million tyres reach the end of their useful lives every year and 5000 millions more are expected to be discarded in a regular basis by the year 2030. Up to now a small part is recycled and millions of tyres are just stockpiled, landfilled or buried. As for PET bottles annual consumption represent more than 300,000 million units. The majority is just landfilled. This paper reviews research published on the performance of concrete containing tyre rubber and PET wastes. Furthermore it discusses the effect of waste treatments, the size of waste particles and the waste replacement volume on the fresh and hardened properties of concrete. © 2011 Elsevier Ltd. All rights reserved.

Govindan K.,University of Southern Denmark | Zhu Q.,Dalian University of Technology | Kannan D.,Indian Institution of Industrial Engineering
International Journal of Production Economics | Year: 2012

Due to growing economic environment and the introduction of new technologies in marketing, another topic of great interest to logistics today is the use of contract or third party services. In the complicated business world, the company is involved in reuse, recycling, and remanufacturing functions using a third party logistics provider which has an impact on the total performance of the firm. In the development of the reverse logistics concept and practice, the selection of providers for the specific function of reverse logistics support becomes more important. After scanning the surplus of literatures, it was concluded that multiple dimensions and attributes must be used in the evaluation and selection of 3PRLP. The attributes play an important role in selecting a third party reverse logistics provider (3PRLP). Interpretive structural modeling (ISM) methodology is adopted in this model, which can be used for identifying and summarizing relationships among specific attributes for selecting the best third party reverse logistics provider among the 'n' 3PRLPs. © 2012 Elsevier B.V. All rights reserved.

Ding Y.,Dalian University of Technology
Construction and Building Materials | Year: 2011

Currently there are only few research results for predicting the relationship between deflection and the crack mouth opening displacement (CMOD) of steel fibre reinforced concrete (SFRC) beams. A series of bending beam tests on SFRC, with different fibre contents and fibre types have been carried out. Based on the experimental results a model for predicting the relation between the deflection and CMOD of SFRC has been established. This model relies on the load-deflection relation and the load-CMOD relation of bending beam. A well agreement has been found between the suggested mode and the test results of other research. The results of this mode indicate that the load-deflection diagram is very similar to that of the load-CMOD diagram, and there is a linear relation between the mid-span deflection and CMOD of SFRC. © 2010 Elsevier Ltd. All rights reserved.

Lin D.,University of Sichuan | Wang X.,Dalian University of Technology | Yao Y.,University of Sichuan
Nonlinear Dynamics | Year: 2012

The contribution of this work is to study the control of unknown chaotic systems with input saturation, and the backstepping-based an adaptive fuzzy neural controller (AFNC) is proposed. In many practical dynamic systems, physical input saturation on hardware dictates that the magnitude of the control signal is always constrained. Saturation is a potential problem for actuators of control systems. It often severely limits system performance, giving rise to undesirable inaccuracy or leading instability. To deal with saturation, we construct a new system with the same order as that of the plant. With the error between the control input and saturation input as the input of the constructed system, a number of signals are generated to compensate the effect of saturation. Finally, simulation results show that the AFNC can achieve favorable tracking performances. © 2011 Springer Science+Business Media B.V.

Xu H.,Dalian University of Technology | Zheng M.,Dalian Jiaotong University
Journal of Transportation Engineering | Year: 2012

Curb bus-only lanes and median bus-only lanes are two commonly used types of the on-street running ways of bus rapid transit (BRT) systems. Transit signal priority (TSP) has proven viable in improving transit schedule adherence and in expediting transit service and is recognized as a key element of BRT systems. From a TSP designer's point of view, it provides a systematic analysis of the impact of bus-only lanes location on the development and performance of the logic rule-based bus rapid transit signal priority (BRTSP). As an emerging active TSP for use at isolated signalized intersections, BRTSP is centered on five categories of logic rules and can fully accommodate the variety of phase scheme. Green extension, early green, and phase insertion can be provided to prioritized vehicles within specific priority windows. The signal operations on bus-only lanes and general-purpose lanes are influenced by prioritized vehicle arrivals and departures and general traffic demands that are detected. Compared with curb bus-only lanes arrangement, median bus-only lanes arrangement imposes more restrictions on the establishment of phase combinations and phase sequences, resulting in less flexibility in assigning right-of-way at an intersection level. Among the components of BRTSP, the bus-only lanes location influences the first minimum green time calculation for vehicle phases, the walk interval calculation for pedestrian phases, the definition of priority windows, the design of logic rules, and the placement of prioritized vehicle detectors. The results of simulation experiments conducted by VISSIM under heavy load scenarios indicated the following: (1) no matter the bus-only lanes location, the phase sequence with all the through-vehicle phases defined as the initial phase had the potential to better moderate the negative effect of signal priority treatments on general traffic and pedestrians; (2) insufficient evidence could not prove that median bus-only lanes arrangement had an overwhelming advantage over curb bus-only lanes arrangement in reducing the delays of prioritized vehicles at traffic signals and vice versa; instead, more attention should be paid to general traffic and pedestrians performance when arranging and managing the bus-only lanes; and (3) curb bus-only lanes arrangement appeared to have an advantage over median bus-only lanes arrangement in improving overall intersection performance if green extension and early green were provided to TSP-enabled intersections. To keep general traffic and pedestrians performance from severely deteriorating, phase insertion service, if desired (in addition to green extension and early green), should be provided only to intersections with median bus-only lanes in a conditional manner. © 2012 American Society of Civil Engineers.

Yang F.,Tohoku University | Jin T.,Tohoku University | Bao M.,Dalian University of Technology | Yamamoto Y.,Tohoku University
Chemical Communications | Year: 2011

A facile, efficient, and general synthetic method for a wide range of 2,3-diiodinated 1,4-dihydrothiophenes and naphthalenes has been developed via the electrophilic iodocyclization of various aryl propargyl alcohols. The resulting product 2p can be used for the synthesis of a rubrene intermediate. © The Royal Society of Chemistry.

Yang M.-H.,Xinyang Normal University | Han Z.-Q.,Dalian University of Technology
Nonlinear Analysis: Real World Applications | Year: 2012

In this paper, we study the existence and multiplicity results for the nonlinear SchrödingerPoisson systems -Δu+V(x)u+K(x)φ(x)u=f(x,u), in R 3,-Δφ=K(x) u2,in R 3. Under certain assumptions on V, K and f, we obtain at least one nontrivial solution for (*) without assuming the Ambrosetti and Rabinowitz condition by using the mountain pass theorem, and obtain infinitely many high energy solutions when f(x,·) is odd by using the fountain theorem. © 2011 Elsevier Ltd. All rights reserved.

Yang F.,Tohoku University | Jin T.,Tohoku University | Bao M.,Dalian University of Technology | Yamamoto Y.,Tohoku University
Chemical Communications | Year: 2011

A facile, efficient, and general synthetic method for 3,4-dihalofurans has been developed via the electrophilic iodocyclization of various 4-hydroxy-2-but-2-yn-1-ones. The use of MeOH as a solvent is crucial for the efficient chemoselective synthesis of the corresponding 3,4-dihalofurans. © 2011 The Royal Society of Chemistry.

Ji S.,Dalian University of Technology
Science China: Physics, Mechanics and Astronomy | Year: 2013

The quasi-solid-liquid phase transition exists widely in different fields, and attracts more attention due to its instinctive mechanism. The structure of force chains is an important factor to describe the phase transition properties. In this study, the discrete element model (DEM) is adopted to simulate a simple granular shear flow with period boundary condition on micro scale. The quasi-solid-liquid phase transition is obtained under various volume fractions and shear rates. Based on the DEM results, the probability distribution functions of the inter-particle contact force are obtained in different shear flow phases. The normal, tangential and total contact forces have the same distributions. The distribution can be fitted as the exponential function for the liquid-like phase, and as the Weibull function for the solid-like phase. To describe the progressive evolution of the force distribution in phase transition, we use the Weibull function and Corwin-Ngan function, respectively. Both of them can determine the probability distributions in different phases and the Weibull function shows more reasonable results. Finally, the force distributions are discussed to explain the characteristics of the force chain in the phase transition of granular shear flow. The distribution of the contact force is an indicator to determine the flow phase of granular materials. With the discussions on the statistical properties of the force chain, the phase transition of granular matter can be well understood. © Science China Press and Springer-Verlag 2013.

Tang B.,Dalian University of Technology | Brennan M.J.,Sao Paulo State University
Journal of Sound and Vibration | Year: 2013

The vibration transmissibility characteristics of a single-degree-of- freedom (SDOF) passive vibration isolation system with different nonlinear dampers are investigated in this paper. In one configuration, the damper is assumed to be linear and viscous, and is connected to the mass so that it is perpendicular to the spring (horizontal damper). The vibration is in the direction of the spring. The second configuration is one in which the damper is in parallel with the spring but the damping force is proportional to the cube of the relative velocity across the damper (cubic damping). Both configurations are studied for small amplitudes of excitation, when some analysis can be conducted based on analytical expressions, and for large amplitudes of excitation, where the analysis is based on numerical simulations. It is found that the two nonlinear systems can outperform the linear system when force transmissibility is considered. However, for displacement transmissibility, the system with the horizontal damper exhibits some desirable properties, but the system with cubic damping does not. © 2012 Elsevier Ltd.

Zhang P.,Dalian Maritime University | Zhao J.,Dalian University of Technology
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2014

We report an atomistic study of energetics and configurations of He-He pair in vacancy of bcc transition metals (V, Nb, Ta, Cr, Mo, W, and Fe) using first-principles methods. The results show He-vacancy attractions in the group VB metals are 2-3 times weaker than those in Cr, Mo, W and Fe. The 〈111〉 dumbbell configuration for He-He pair in vacancy is the most stable except for V. Calculated formation energies of He-He pair in vacancy of group VB metals (3.2-3.95 eV) are systematically lower than those of group VIB and VIIIB metals (4.25-5.67 eV), while He-He distance for V metal is greater than other metals. He-metal repulsion is stronger than He-He due to longer He-metal distance in metal vacancy. Calculated densities of states provide a reasonable explanation for most stable configuration; thus the stability of He-He pairs depends strongly on the electronic structure of the host and insignificantly on its atomic size. Moreover, the group-specific trends of He-He and self-interstitial configurations are discussed. © 2014 Elsevier B.V. All rights reserved.

Sun H.,Dalian University of Technology | Sun H.,University of Jinan | Yue C.-X.,Liaoning Normal University
European Physical Journal C | Year: 2014

We study the photoproduction of the charged top-pion predicted by the top triangle moose (TTM) model (a deconstructed version of the topcolor-assisted technicolor TC2 model) via the processes (Formula presented.) at the 14 TeV Large Hadron Collider (LHC) including next-to-leading order (NLO) QCD corrections. Our results show that the production cross sections and distributions are sensitive to the free parameters sinω and Mπt. A typical QCD correction value is 7-11% and this does not depend much on sinω as well as the forward detector acceptances. © 2014 The Author(s).

Chen S.-Y.,Dalian University of Technology
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2013

The theorem of the relative differences evolution, which is based on the theorem of variable sets and mathematical laws of basic laws of dialectics, is introduced in this paper. It also introduced the pattern recognition matrix and evaluation principle and method for water resource systems with the former supportive effects. An evolution on the coordination in four planning level years for the sustainable use of water resources in Dongguan city, Guangdong Province is taken as an example and demonstrates some comparisons and analysis between variable sets and set pair analysis are demonstrated. Then it points the problems of set pair analysis. From the comparison and analysis, it shows that the evaluation principle and method for water resource systems that based on the variable theory have more advantages. With much rigorous theory and clear concepts, the calculation is much more simple and convenient. The method this article introduced can be extended to many academic fields including: environmental engineering, hydraulic and hydro-power engineering, civil and architectural engineering, management engineering, etc. It has a very broad application prospect.

Xu Z.,University of Western Australia | Hao H.,University of Western Australia | Li H.N.,Dalian University of Technology
Construction and Building Materials | Year: 2012

This paper presents a numerical simulation of dynamic impact tests on steel fibre reinforced concrete (SFRC) specimens to study the dynamic material properties of SFRC. In the analysis, an axisymmetric mesoscale SFRC model is developed with distinctive consideration of the fibres, aggregates and cement mortar to investigate the dynamic failure behaviour of SFRC material under impact loading at different strain rates. The SFRC model composes of three components, i.e., the high strength coarse aggregates, cementitious mortar and steel fibres. To simplify the model, the coarse aggregates are assumed to have circular shape with randomly distributed size and location in the SFRC specimen. The hooked-end steel fibres are also randomly distributed in the specimen with random orientations. The developed model is used to numerically simulate a Split Hopkinson Pressure Bar Test (SHPB) on SFRC specimens. The model is created with commercial software ANSYS and VPG whilst the dynamic impact tests are simulated with the explicit hydrocode LS-DYNA. Numerical results are compared with available experimental data to verify the developed model. The verified numerical model is then used to perform a series of simulations of SFRC specimens with different volume fractions of steel fibres or without steel fibre under dynamic impact loads of different loading rates. From the numerical results, the influences of steel fibres on dynamic material properties, in particular the dynamic increase factor (DIF), and on dynamic failure mechanism of SFRC are discussed. The DIF of SFRC with different steel fibre dosages are derived from the numerical results. © 2011 Elsevier Ltd. All rights reserved.

Sun H.,Dalian University of Technology
European Physical Journal C | Year: 2014

Abstract Observing light-by-light scattering at the large hadron collider (LHC) has received quite some attention and it is believed to be a clean and sensitive channel to possible new physics. In this paper, we study the diphoton production at the LHC via the process pp → pγγ p → pγγ p through graviton exchange in the large extra dimension (LED)model. Typically, when we do the background analysis, we also study the double Pomeron exchange of γγ production. We compare its production in the quark–quark collision mode to the gluon–gluon collision mode and find that contributions from the gluon–gluon collision mode are comparable to the quark–quark one. Our result shows, for extra dimension δ = 4, with an integrated luminosity L = 200 fb−1 at the 14 TeV LHC, that diphoton production through graviton exchange can probe the LED effects up to the scale MS = 5.06(4.51, 5.11) TeV for the forward detector acceptance ξ1(ξ2, ξ3), respectively, where 0.0015 < ξ1 < 0.5, 0.1 < ξ2 < 0.5, and 0.0015 < ξ3 < 0.15. © 2014, The Author(s).

Xu D.-M.,Henan Institute of Engineering | Qiu L.,North China University of Water Conservancy and Electric Power | Chen S.,Dalian University of Technology
Journal of Hydrologic Engineering | Year: 2012

The accurate estimation of Muskingum model parameter is essential to give flood routing for flood control in water resources management. The Muskingum model continues to be a popular method for flood routing, and its parameter estimation is a global optimization problem with the main objective to find a set of optimal model parameter values that attains a best fit between observed and computed flow. Although some techniques have been employed to estimate the parameters for Muskingum model, an efficient method for parameter estimation in Muskingum model is still required to improve the computational precision. Therefore, in this paper, the differential evolution (DE) algorithm is studied for estimation of Muskingum model parameter. A case study with actual data from previous literature, the experimental results showed an excellent performance in its optimization result and performance analysis and demonstrates that DE is an alternative technique to estimate the parameters of the Muskingum model. © 2012 American Society of Civil Engineers.

Liu Y.,Ocean University of China | Li H.-J.,Ocean University of China | Li Y.-C.,Dalian University of Technology
Ocean Engineering | Year: 2012

This study gives a new analytical solution for water wave scattering by a submerged horizontal porous plate breakwater with finite thickness in the context of linear potential theory. The original velocity potential is split into a symmetric part and an antisymmetric part. Each part is further written as the sum of two artificial potentials satisfying appropriate boundary conditions. All the artificial potentials are determined by the matched eigenfunction expansions. The symmetric solution is also the solution for wave reflection by a porous plate wave absorber in laboratory flume. A multi-domain boundary element method solution is developed to confirm the analytical solution. The agreement between the results calculated by the analytical solution and the boundary element method solution is excellent. Also the analytical solution is confirmed by experimental data. The new analytical solution needs no complex dispersion relations for water wave motion over porous mediums. Thus the particular difficulties due to complex dispersion relations are avoided. © 2012 Elsevier Ltd. All rights reserved.

Miles B.T.,University of Bristol | Hong X.,Dalian University of Technology | Gersen H.,University of Bristol
Optics Express | Year: 2015

The ability to characterize the Point Spread Function(PSF) is crucial in practical microscopy, but requires knowledge of the complex PSF for approaches that detect fields instead of intensities. Here we experimentally measure and theoretically model the volumetric amplitude and phase response of an Interferometric Cross-polarisation Microscope to demonstrate the technique's capability to provide confocal-like images of weakly birefringent structures in living cells. We find the axial FWHM of the amplitude PSF to be 0:70±0:01 μm and 0:83 μm for model and measurement, respectively, on par with confocal microscopy. Ultimately retaining both amplitude and phase information will however enable approaches for improved localisation of objects. © 2015 Optical Society of America.

Tang Z.,Petrochina | Li S.,Petrochina | Li S.,Dalian University of Technology
Current Opinion in Solid State and Materials Science | Year: 2014

Due to the increasing demand of low emission and fuel economy, friction modifiers have been widely used in lubricating compositions to adjust friction and wear properties of lubricants. Recent achievements in the application of friction modifiers for liquid lubricants (2007-present) are reviewed in this paper. There are three types of friction modifiers for liquid lubricants: organomolybdenum compounds, organic friction modifiers, as well as nanoparticles. The tribological properties and lubrication mechanisms of these friction modifiers are discussed. The problems and some suggestions for the future directions of research on friction modifiers are proposed. © 2014 Elsevier Ltd. All rights reserved.

Wang C.,U.S. Food and Drug Administration | Wang Z.,Dalian University of Technology | Prows D.R.,University of Cincinnati | Wu R.,Pennsylvania State University
Briefings in Bioinformatics | Year: 2012

Genetic imprinting, by which the expression of a gene depends on the parental origin of its alleles, may be subjected to reprogramming through each generation. Currently, such reprogramming is limited to qualitative description only, lacking more precise quantitative estimation for its extent, pattern and mechanism. Here, we present a computational framework for analyzing the magnitude of genetic imprinting and its transgenerational inheritance mode. This quantitative model is based on the breeding scheme of reciprocal backcrosses between reciprocal F1 hybrids and original inbred parents, in which the transmission of genetic imprinting across generations can be tracked. We define a series of quantitative genetic parameters that describe the extent and transmission mode of genetic imprinting and further estimate and test these parameters within a genetic mapping framework using a new powerful computational algorithm. The model and algorithm described will enable geneticists to identify and map imprinted quantitative trait loci and dictate a comprehensive atlas of developmental and epigenetic mechanisms related to genetic imprinting. We illustrate the new discovery of the role of genetic imprinting in regulating hyperoxic acute lung injury survival time using a mouse reciprocal backcross design. © The Author 2011. Published by Oxford University Press.

Wang X.,East China Normal University | Cai X.,Shanghai University | Hu J.,Dalian University of Technology | Shao N.,East China Normal University | And 4 more authors.
Journal of the American Chemical Society | Year: 2013

Polymeric nanoparticles that can stably load anticancer drugs and release them in response to a specific trigger such as glutathione are of great interest in cancer therapy. In the present study, dendrimer-encapsulated gold nanoparticles (DEGNPs) were synthesized and used as carriers of thiolated anticancer drugs. Thiol-containing drugs such as captopril and 6-mercaptopurine loaded within DEGNPs showed an "Off-On" release behavior in the presence of thiol-reducing agents such as glutathione and dithiothreitol. Thiolated doxorubicin and cisplatin, loaded within the nanoparticle, showed much reduced cytotoxicity as compared to the free anticancer compounds. The toxicity of drug-loaded DEGNPs can be enhanced by improving the intracellular glutathione. Glutathione-triggered release of thiolated doxorubicin within cancer cells is further confirmed by flow cytometry and confocal laser scan microscopy studies. In addition, DEGNPs showed excellent biocompatibility on several cell lines. This study provides a new insight into biomedical applications of dendrimers and dendrimer-encapsulated nanoparticles. © 2013 American Chemical Society.

Niu Y.-J.,Dalian University | Wang X.-Y.,Dalian University of Technology
Nonlinear Dynamics | Year: 2013

This paper is concerned with the stabilization problem for a class of uncertain chaotic systems. Based on a set of linguistic rules, a novel variable universe fuzzy sliding-mode control approach is designed to improve the robustness and the stability of system. Based on Lyapunov stability theory, the overall closed-loop system is shown to be stable. The designed controller not only can control the uncertain chaotic system to a desired state, but also the control action is smooth without chattering. Simulation examples are presented to further illustrate the advantage of the proposed method. © 2012 Springer Science+Business Media B.V.

Chen G.-J.,CAS Changchun Institute of Applied Chemistry | Han F.-S.,CAS Changchun Institute of Applied Chemistry | Han F.-S.,Dalian University of Technology
European Journal of Organic Chemistry | Year: 2012

The Suzuki-Miyaura cross-coupling of aryl sulfamates and boronic acids was investigated by using [1,3-bis(diphenylphosphanyl)propane]nickel(II) chloride {NiCl 2(dppp)} as the catalyst. The results showed that NiCl 2(dppp) is a highly active and general catalyst that allows effective Suzuki-Miyaura cross-coupling of aryl sulfamates with a slight excess amount of the boronic acid (1.2 equiv.) in the presence of a low catalyst loading (generally 1.0-1.5 mol-%). The method also displays broad generality not only to various aryl sulfamates, but also to an array of boronic acids. Furthermore, various functional groups are tolerated. These apparent advantages make NiCl 2(dppp) a practical and reliable catalyst system for the Suzuki-Miyaura coupling of aryl sulfamates. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li R.,State Key Laboratory of Structural Analysis for Industrial Equipment | Zhong Y.,Dalian University of Technology | Li M.,State Key Laboratory of Structural Analysis for Industrial Equipment
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2013

Analytic bending solutions of free rectangular thin plates resting on elastic foundations, based on the Winkler model, are obtained by a new symplectic superposition method. The proposed method offers a rational elegant approach to solve the problem analytically, which was believed to be difficult to attain. By way of a rigorous but simple derivation, the governing differential equations for rectangular thin plates on elastic foundations are transferred into Hamilton canonical equations. The symplectic geometry method is then introduced to obtain analytic solutions of the plates with all edges slidingly supported, followed by the application of superposition, which yields the resultant solutions of the plates with all edges free on elastic foundations. The proposed method is capable of solving plates on elastic foundations with any other combinations of boundary conditions. Comprehensive numerical results validate the solutions by comparison with those obtained by the finite element method. Copyright © The Royal Society 2013.

Zhao J.,Tohoku University | Oniwa K.,Tohoku University | Asao N.,Tohoku University | Yamamoto Y.,Tohoku University | And 2 more authors.
Journal of the American Chemical Society | Year: 2013

A novel and selective Pd-catalyzed cascade crossover-annulation of o-alkynylarylhalides and diarylacetylenes for the synthesis of dibenzo[a,e]pentalenes has been reported. Various arylacetylenes with a wide range of functional groups were tolerated, producing the corresponding multisubstituted dibenzopentalenes with the different substituents on the aromatic rings in good to high yields under the optimized reaction conditions. The reaction proceeds through a Pd-catalyzed cascade carbopalladation and C-H activation. The use of the combined DBU and CsOPiv bases is crucial for the successful implementation of the present cross-annulation. © 2013 American Chemical Society.

Wang R.,Dalian University of Technology | Wang R.,Clarkson University | Shen H.H.,Clarkson University
Journal of Geophysical Research: Oceans | Year: 2010

A viscoelastic model is proposed to describe the propagation of gravity waves into various types of ice cover. The ice-ocean system is modeled as a homogeneous viscoelastic fluid overlying an inviscid layer. Both layers have finite thickness. The viscosity is imagined to originate from the frazil ice or ice floes much smaller than the wavelength, and the elasticity from ice floes which are relatively large compared to the wavelength. A compact form of the dispersion relation is obtained. Under proper limiting conditions this dispersion relation can be reduced to several previously established models including the mass loading model, the viscous layer model and the thin elastic plate model. The full dispersion relation contains several propagating wave modes under the ice cover. The following two criteria are used to select the dominant wave mode: (1) wave number is the closest to the open water value and (2) attenuation rate is the least among all modes. The modes selected from those criteria coincide with the ones discussed in previous studies, which are shown to be limiting cases in small or large elasticity regimes of the present model. In the intermediate elasticity regime, however, it appears that there are three wave modes with similar wavelengths and attenuation rates. Implications of this intermediate elasticity range remain to be seen. The general viscoelastic model bridges the gap among existing models. It also provides a unified tool for wave-ice modelers to parameterize the polar regions populated with various types of ice cover. Copyright 2010 by the American Geophysical Union.

Zhu Q.,Dalian University of Technology | Geng Y.,CAS Shenyang Institute of Applied Ecology
Journal of Cleaner Production | Year: 2013

Due to increasing energy scarcity and environmental issues as well as the goal to develop low carbon society, the Chinese government initiated a comprehensive Energy Saving and Emission Reduction (ESER) program for sustainable production and consumption in 2005. Under the ESER program, Chinese manufacturers have struggled to reduce their environmental pollution and energy consumption. To achieve their ESER goals, Chinese manufacturers should cooperate with their suppliers and customers. However, it is not clear how to drive Chinese manufacturers to implement extended supply chain (ESC) practices for ESER goals, and what kinds of barriers exist. By utilizing a total of 299 usable questionnaires, we did descriptive analysis. Statistic results show that Chinese manufacturers implement ESC practices for ESER goals at a low level. Coercive, normative and mimetic drivers are generally weak while internal barriers are relatively higher. We further used hierarchical analysis to examine whether drivers motivate Chinese manufacturers to implement ESC practices for ESER goals, and whether barriers impede ESC practices. Main regression results and implications include: (1) Coercive drivers do not really motivate ESC practices for ESER goals. To promote ESC practices for the ESER goals, the Chinese government should enact stricter regulations and strengthen their enforcement level. (2) Normative drivers motivate Chinese manufacturers to implement sustainable purchasing. With the increasing environmental awareness of Chinese consumers, Chinese manufactures will have higher normative drivers and then be more proactive to implement sustainable purchasing. (3) Mimetic drivers promote both sustainable purchasing and sustainable customer cooperation. By learning from manufacturers in developed countries, especially those operating in China, Chinese manufacturers tend to implement ESC practice for ESER goals. (4) Internal barriers, such as lack of financial gains, resource and capability, are main obstacles for the implementation of sustainable customer cooperation. Thus, how to overcome internal barriers is a key for Chinese manufacturers to effectively and efficiently implement ESC practices for ESER goals. © 2010 Elsevier Ltd. All rights reserved.

Wang W.,China University of Mining and Technology | Liu R.,China University of Mining and Technology | Zhang M.,China University of Mining and Technology | Li H.,Dalian University of Technology
Energy for Sustainable Development | Year: 2013

Jiangsu Province has become one of the most developed regions in China. Economic growth in Jiangsu has occurred along with rising CO2 emission levels. A deeper understanding of how energy-related CO2 emissions have evolved in Jiangsu Province is very important in formulating future policies. Thus it is very necessary to investigate the driving forces governing CO2 emissions and their evolution. The decoupling index combined with the LMDI (Log Mean Divisia Index) method is used to analyze the contribution of the factors which influence energy-related CO2 emissions in Jiangsu Province over the period 1995-2009. The results show that economic activity is the critical factor in the growth of energy-related CO2 emissions in Jiangsu Province, and the energy intensity effect plays the dominant role in decreasing CO2 emissions. The period from 2003 to 2005 represents a re-coupling effect; the periods 1996-1997 and 2000-2001 indicate strong decoupling effect, while the remaining time intervals show weak decoupling effect. © 2012.

Xu L.,Dalian University of Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

In this paper, the holographic dark energy model, where the future event horizon is taken as an IR cutoff, is confronted by using currently available cosmic observational data sets which include type Ia supernovae, baryon acoustic oscillation, and cosmic microwave background radiation from full information of WMAP 7-yr data. Via the Markov chain Monte Carlo method, we obtain the values of model parameter c=0.696-0.0737-0.132-0.190+0.0736+0.159+0.264 with 1, 2, 3σ regions. Therefore, one can conclude that at at least 3σ level the future Universe will be dominated by phantom-like dark energy. It is not consistent with positive energy condition, however this condition must be satisfied to derive the holographic bound. It implies that the current cosmic observational data points disfavor the holographic dark energy model. © 2012 American Physical Society.

Xu X.,Northwest University, China | Wang X.,Northwest University, China | Li Y.,Dalian University of Technology | Wang Y.,Northwest University, China | Yang L.,CAS Dalian Institute of Chemical Physics
Nucleic Acids Research | Year: 2012

Nano-scale particles have attracted a lot of attention for its potential use in medical studies, in particular for the diagnostic and therapeutic purposes. However, the toxicity and other side effects caused by the undesired interaction between nanoparticles and DNA/RNA are not clear. To address this problem, a model to evaluate the general rules governing how nanoparticles interact with DNA/RNA is demanded. Here by, use of an examination of 2254 native nucleotides with molecular dynamics simulation and thermodynamic analysis, we demonstrate how the DNA/RNA native structures are disrupted by the fullerene (C60) in a physiological condition. The nanoparticle was found to bind with the minor grooves of double-stranded DNA and trigger unwinding and disrupting of the DNA helix, which indicates C60 can potentially inhibit the DNA replication and induce potential side effects. In contrast to that of DNA, C60 only binds to the major grooves of RNA helix, which stabilizes the RNA structure or transforms the configuration from stretch to curl. This finding sheds new light on how C60 inhibits reverse transcription as HIV replicates. In addition, the binding of C60 stabilizes the structures of RNA riboswitch, indicating that C60 might regulate the gene expression. The binding energies of C60 with different genomic fragments varies in the range of -56 to -10 kcal mol-1, which further verifies the role of nanoparticle in DNA/RNA damage. Our findings reveal a general mode by which C60 causes DNA/RNA damage or other toxic effects at a systematic level, suggesting it should be cautious to handle these nanomaterials in various medical applications. © 2012 The Author(s).

Zhao J.,Tohoku University | Asao N.,Tohoku University | Yamamoto Y.,Tohoku University | Yamamoto Y.,Dalian University of Technology | Jin T.,Tohoku University
Journal of the American Chemical Society | Year: 2014

We report a novel Pd-catalyzed alkyne-directed dual C-H activation of bis-biaryl alkynes, which produced important and useful products, 9,9-bifluorenylidene (9,9BF) derivatives, in high yields with a broad range of functional group compatibility. The combination of the PdCl2 catalyst with the MnO2 oxidant and PivOH additive is vital for realization of the present catalytic transformation. Mechanistic evidence suggests that this intramolecular arene/alkyne annulation may take place through unusual dual C-H activation followed by annulation with alkynes. © 2014 American Chemical Society.

Xu T.,Colorado State University | Xu T.,Dalian University of Technology | Chen E.Y.-X.,Colorado State University
Journal of the American Chemical Society | Year: 2014

The first highly active phosphine (P)/borane (B) Lewis pair polymerization is promoted unexpectedly by P-B adducts. The P and B site cooperativity is essential for achieving effective polymerization, as shown by this study examining the reactivity of a library of P/B Lewis pairs toward polymerization of a renewable acrylic monomer. © 2014 American Chemical Society.

Duan Y.,CAS Dalian Institute of Chemical Physics | Li L.,Dalian University of Technology | Chen M.-W.,CAS Dalian Institute of Chemical Physics | Yu C.-B.,CAS Dalian Institute of Chemical Physics | And 2 more authors.
Journal of the American Chemical Society | Year: 2014

An efficient palladium-catalyzed asymmetric hydrogenation of a variety of unprotected indoles has been developed that gives up to 98% ee using a strong Brønsted acid as the activator. This methodology was applied in the facile synthesis of biologically active products containing a chiral indoline skeleton. The mechanism of Pd-catalyzed asymmetric hydrogenation was investigated as well. Isotope-labeling reactions and ESI-HRMS proved that an iminium salt formed by protonation of the C=C bond of indoles was the significant intermediate in this reaction. The important proposed active catalytic Pd-H species was observed with 1H NMR spectroscopy. It was found that proton exchange between the Pd-H active species and solvent trifluoroethanol (TFE) did not occur, although this proton exchange had been previously observed between metal hydrides and alcoholic solvents. Density functional theory calculations were also carried out to give further insight into the mechanism of Pd-catalyzed asymmetric hydrogenation of indoles. This combination of experimental and theoretical studies suggests that Pd-catalyzed hydrogenation goes through a stepwise outer-sphere and ionic hydrogenation mechanism. The activation of hydrogen gas is a heterolytic process assisted by trifluoroacetate of Pd complex via a six-membered-ring transition state. The reaction proceeds well in polar solvent TFE owing to its ability to stabilize the ionic intermediates in the Pd-H generation step. The strong Brønsted acid activator can remarkably decrease the energy barrier for both Pd-H generation and hydrogenation. The high enantioselectivity arises from a hydrogen-bonding interaction between N-H of the iminium salt and oxygen of the coordinated trifluoroacetate in the eight-membered-ring transition state for hydride transfer, while the active chiral Pd complex is a typical bifunctional catalyst, effecting both the hydrogenation and hydrogen-bonding interaction between the iminium salt and the coordinated trifluoroacetate of Pd complex. Notably, the Pd-catalyzed asymmetric hydrogenation is relatively tolerant to oxygen, acid, and water. © 2014 American Chemical Society.

Peng Y.,Dalian University of Technology
Journal of Computers | Year: 2011

Based on traditional artificial fish swarm algorithm (AFSA), an improved artificial fish swarm algorithm (IAFSA) is proposed and used to solve the problem of optimal operation of cascade reservoirs. To improve the ability of searching the global and the local extremum, the vision and the step of artificial fish are adjusted dynamicly in IAFSA. Moreover, to increase the convergence speed, the threshold selection strategy is employed to decrease the individual large space gap between before and after update operation in the local update operation. The validity of IAFSA is proved by case study and the threshold parameters of IAFSA are rated.

He R.,CAS Institute of Automation | Hu B.-G.,CAS Institute of Automation | Zheng W.-S.,Sun Yat Sen University | Kong X.-W.,Dalian University of Technology
IEEE Transactions on Image Processing | Year: 2011

Principal component analysis (PCA) minimizes the mean square error (MSE) and is sensitive to outliers. In this paper, we present a new rotational-invariant PCA based on maximum correntropy criterion (MCC). A half-quadratic optimization algorithm is adopted to compute the correntropy objective. At each iteration, the complex optimization problem is reduced to a quadratic problem that can be efficiently solved by a standard optimization method. The proposed method exhibits the following benefits: 1) it is robust to outliers through the mechanism of MCC which can be more theoretically solid than a heuristic rule based on MSE; 2) it requires no assumption about the zero-mean of data for processing and can estimate data mean during optimization; and 3) its optimal solution consists of principal eigenvectors of a robust covariance matrix corresponding to the largest eigenvalues. In addition, kernel techniques are further introduced in the proposed method to deal with nonlinearly distributed data. Numerical results demonstrate that the proposed method can outperform robust rotational-invariant PCAs based on L1 norm when outliers occur. © 2010 IEEE.

Yang Y.-F.,Dalian University of Technology | Hou C.,Tsinghua University
Magazine of Concrete Research | Year: 2015

This paper describes research work on the performance and design calculations of recycled aggregate concrete filled steel tube (RACFST) members, especially the most recent developments in China. Firstly, experimental studies on RACFST members subjected to short-term static loading, long-term sustained loading and cyclic flexural loading are summarised and analysed, and recent advances in the behaviour of RACFST stub columns after exposure to high temperatures (300-8008C) are also reviewed. The experimental results show that, in general, RACFST members have similar performance to concrete filled steel tube (CFST) members when subjected to the same loading conditions. However, due to the more serious inherent defects of recycled aggregate concrete compared with normal concrete, RACFST members have a lower bearing capacity and stiffness than their CFST counterparts. Secondly, design formulae for RACFST members are suggested and the calculated bearing capacities using the simplified equations generally agree well with the experimental results. Finally, the potential research needs of RACFST structures are discussed.

Lu H.,Dalian University of Technology
Bioresource technology | Year: 2010

The effect of anthraquinone-2-sulfonate covalently immobilized in PUF (AQS-PUF) on the decolorization of azo dyes by Escherichia coli K12 was investigated. The results showed that AQS-PUF mediated biodecolorization rate of azo dye amaranth increased over 5-fold compared with that lacking AQS, and the kinetics of its biodecolorization could be described using Quiroga second order equation. During the above process, a lot of the cells of E. coli K12 were attached in the walls of AQS-PUF pores. After 10 repeated experiments using AQS-PUF, immobilized AQS-mediated biodecolorization efficiency of amaranth retained over 98.7% of their original value. Moreover, AQS-PUF could greatly enhance the decolorization rates of a broad range of azo dyes. These results indicated that AQS-PUF as a biocarrier exhibited high catalytic activity and good stability for potential applications. Copyright 2010 Elsevier Ltd. All rights reserved.

Song B.,CAS Shanghai Institute of Applied Physics | Yang J.,Sichuan University | Zhao J.,Dalian University of Technology | Fang H.,CAS Shanghai Institute of Applied Physics
Energy and Environmental Science | Year: 2011

The intercalation and diffusion of lithium ions in a bundle of carbon nanotubes (CNTs) are investigated via an ab initio molecular dynamics simulation method based on the density functional theory. We found that lithium ions quickly penetrate into the CNTs and the space between neighboring CNTs. With a low Li ion density, the Li ions tend to stay close to the nanotube ends. Interestingly, Li ions are able to penetrate through the carbon nanotube and move from one end to the other. We also discovered that Li ions may remain between two neighboring CNTs, which presents a new approach for Li ion intercalation and storage. Importantly, Li ions located among three neighboring CNTs have very strong adsorption potentials that are a factor of four larger than those of Li ions located along the central axis of a single-walled nanotube (SWNT). This indicates that Li ions located among three neighboring CNTs would be very difficult to remove from a nanotube bundle, which suggests that Li storage capacity in this case is possibly irreversible, and that keeping the nanotubes apart with an appropriate distance would hinder or promote the formation of irreversible intercalation. Our findings contribute to the understanding of lithium intercalation and diffusion in CNTs, which has implications for the experimental development and application of rechargeable Li ion batteries. © 2011 The Royal Society of Chemistry.

Wang J.-B.,Shenyang Aerospace University | Wang J.-J.,Dalian University of Technology
International Journal of Production Research | Year: 2015

We study resource allocation scheduling with job-dependent learning effect on a single machine with or without due date assignment considerations. For a convex resource processing time function, we provide a polynomial time algorithm to find the optimal job sequence, and resource allocations that minimise the schedule criterion (the total compression cost) subject to the constraint that the total compression cost (the schedule criterion) is less than or equal to a fixed amount. © 2015 Taylor & Francis.

By using a 15m thick, well-dated basic sill as an example, this study presents an investigation on the effect of errors in thermophysical parameters of igneous intrusions and over-simplification in heat transfer equations as well as uncertainties in pore-water volatilization and intrusion mechanisms of magma on quantitative evaluation of thermal alteration in contact metamorphic aureoles based on heat transfer models and the EASY%Ro model. Our results indicate: 1) Using an under-estimated and temperature-independent specific heat (e.g. ~800Jkg -1°C -1) of igneous intrusions instead of the temperature-dependent specific heat can cause the maximum deviation of 68°C in peak temperature and of 1.3% in vitrinite reflectance, whereas such deviations (less than 26°C and 0.1%) are small enough to be ignored for the model using a high, invariable specific heat (e.g. ~1200Jkg -1°C -1) of igneous intrusions. The specific heat of igneous intrusions is likely a more notable error source in causing model deviations compared to the intrusion temperature and the latent crystallization heat of melted magma, if the latent crystallization heat is allowed for; 2) the effect of the uncertainty in whether pore water volatilized during cooling of intrusive magma on the model prediction can be as notable as that of the use of an under-estimated specific heat. The over-simplification in heat transfer equations (i.e. the variation of thermal conductivity with spatial location is not used) results in an obvious underestimation of the thermal effect of igneous intrusions on host rocks. The model deviation caused by this type of error may be far beyond that caused by the errors in thermophysical parameters of igneous intrusions or the uncertainty in pore-water volatilization; 3) the model deviations due to the errors in the thermophysical parameters and the uncertainty in pore-water volatilization can be large enough to disturb the estimation of the intrusion mechanism based on heat transfer models. By comparing the vitrinite reflectance predicted by different heat transfer models with the measured one, the results from more than one type of model can be found to match well with the observation. Only the model of the finite-time intrusion mechanism can be reasonably regarded as representing natural conditions. It is not fully reliable to validate the availability of the used heat transfer models only by observing whether the model results match with measured geothermometers due to the effect of these uncertainties, errors and over-simplification. More careful model specification and parameter estimation are required in the future use of heat transfer models of igneous intrusions. © 2012 Elsevier B.V.

Han Y.-C.,University of Aarhus | Han Y.-C.,Dalian University of Technology | Madsen L.B.,University of Aarhus
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

The interference minimum in the high-order harmonic spectrum of H 2+ is studied by solving the full three-dimensional time-dependent Schrödinger equation for the electronic motion keeping the nuclei fixed. The two-center interference model works well when the internuclear distance is around its equilibrium value where also recombination to the 2Σg+ (1sσg) ground state dominates. As the internuclear distance is increased, the minimum first shifts in position compared with the prediction of the two-center interference model and subsequently disappears. These effects are caused by the excited 2Σu+ (2pσu) state, partly due to the interference between the amplitudes of recombination to the ground and excited states, but also partly due to the signal associated with recombination to the excited state alone. We find that at internuclear distances beyond Râ‰3 a.u. the signal close to the harmonic cutoff may be completely dominated by recombination into the excited 2Σu+ (2pσu) state. © 2013 American Physical Society.

Wang Z.-T.,Dalian University of Technology
Shanghai Ligong Daxue Xuebao/Journal of University of Shanghai for Science and Technology | Year: 2011

In this paper, the concept of hypernetwork based on hypergraph suggested by C. Berge as another kind of supernetwork is introduced. The main feature of hypernetwork is the edge in hypergraph can be connected to more than one nodes. For the investigation of some complex network like telecommunication network, knowledge network, social network, this unique feature may offer more advantages.

Yuan F.-Q.,CAS Changchun Institute of Applied Chemistry | Yuan F.-Q.,University of Chinese Academy of Sciences | Han F.-S.,CAS Changchun Institute of Applied Chemistry | Han F.-S.,Dalian University of Technology
Advanced Synthesis and Catalysis | Year: 2013

A one-pot cascade reaction for the synthesis of polysubstituted benzofurans and naphthopyrans from simple phenols and propargylic alcohols catalyzed by iron(III) is presented. The results demonstrate that the structural specificity for the formation of furan and pyran products is controlled by the structural nature of the propargylic alcohols. Namely, benzofurans could be synthesized efficiently from phenols and secondary propargylic alcohols in the presence of 5 mol% of iron(III) chloride hexahydrate (FeCl3·6H 2O) catalyst. On the other hand, pyran derivatives were obtained exclusively when tertiary propargylic alcohols were employed. Mechanistic studies revealed that presumably due to the discriminated steric effect of secondary and tertiary propargylic alcohols, the Fe-catalyzed Friedel-Crafts (F-C) reaction of phenols with the two types of alcohols proceeds via different models. Most importantly, we have demonstrated for the first time that fully 2,3,4-substituted naphthopyrans could be synthesized efficiently via the iron-catalyzed one-pot cascade reaction. Consequently, the results presented herein provide straightforward pathways for versatile syntheses of valuable benzofuran and pyran derivatives from simple phenolic compounds and propargylic alcohols. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luo Y.,Northwestern Polytechnical University | Luo Y.,Chinese University of Hong Kong | Wang M.Y.,Chinese University of Hong Kong | Kang Z.,Dalian University of Technology
Computer Methods in Applied Mechanics and Engineering | Year: 2013

By introducing a new reduction parameter into the Kreisselmeier-Steihauser (K-S) function, this paper presents a general K-S formulation providing an approximation to the feasible region restricted by active constraints. The approximation is highly accurate even when the aggregation parameter takes a relatively small value. Numerical difficulties, such as high nonlinearity and serious violation of local constraints that may be exhibited by the original K-S function, are thus effectively alleviated. In the considered topology optimization problem, the material volume is to be minimized under local von Mises stress constraints imposed on all the finite elements. An enhanced aggregation algorithm based on the general K-S function, in conjunction with a " removal and re-generation" strategy for selecting the active constraints, is then proposed to treat the stress constraints of the optimization problem. Numerical examples are given to demonstrate the validity of the present algorithm. It is shown that the proposed method can achieve reasonable solutions with a high computational efficiency in handling large-scale stress constrained topology optimization problems. © 2012 Elsevier B.V.

Luo Y.,Northwestern Polytechnical University | Li A.,University of Reims Champagne Ardenne | Kang Z.,Dalian University of Technology
Engineering Structures | Year: 2012

The steel-concrete composite beam bonded by adhesive has particular advantages over the traditional composite beam. Based on the experimental push-out test, this paper proposes a three-dimensional nonlinear finite element model for the mechanical behaviour simulation of bonded steel-concrete composite beams. The proposed numerical model is validated through comparisons between numerical results and experimental data. The effects of certain parameters, including the elastic modulus of adhesive, the adhesive layer's thickness, the concrete strength, the bonding strength and the bonding area, are investigated. Numerical results show that the influence of most investigated parameters on the response of the bonded composites is very notable, while that of the adhesive layer's thickness (variation within 3-15. mm) is relatively small. © 2011 Elsevier Ltd.

Zhao J.,South China University of Technology | Wu B.,Harbin Institute of Technology | Ou J.,Dalian University of Technology
Journal of Structural Engineering (United States) | Year: 2012

In a previous study by the authors, the cyclic behavior of a novel type of pin-connected angle steel buckling-restrained brace (ABRB) was examined, and the failure mechanism in the core projection of the ABRB induced by an excessive bending effect caused by end rotation was discussed. In this paper, the occurrence mechanism of end rotation modes and the bending effect in the core projection of an ABRB are first investigated based on the previous test results, which shows that end rotation demands would be significantly increased with the presence of a gap and an additional bending effect could be observed if the end rotation demands were large enough to cause two-point contact at the core ends. Then, a new method to predict the flexural demand on pin-connected BRBs is proposed by considering the effect of the end rotation modes, clearance, initial eccentricity, and initial deflection of casing. The design criteria to prevent yielding of the core projection are presented and further verified by the previous test results. Furthermore, the effects of key influential parameters on the flexural demand on core projection are discussed based on the analytical results. It is found that such a bending effect can be significantly reduced by decreasing the gap or increasing the constrained length of the core stiffening segment. The C-mode end rotation with single curvature bending configuration is found to be generally the most unfavorable case for core projection design. Finally, several design recommendations are provided for pin-connected BRBs. © 2012 American Society of Civil Engineers.

Wang L.,Nanchang Hangkong University | Liu X.,Dalian University of Technology
Information Sciences | Year: 2013

This paper is concerned with the problem of computing the bounds of disturbances for continuous-time Takagi-Sugeno fuzzy model. Two kinds of disturbances are investigated by applying the non-parallel distributed compensation (non-PDC) law, non-quadratic Lyapunov function and Lagrange multiplier method. One is bounded by magnitude, the other is bounded by energy. If the exogenous disturbances are bounded by magnitude, the maximal value of the magnitude under which the closed-loop system can be controlled is obtained by solving an optimization problem. On the other hand, if the disturbances are bounded by energy, except for the maximal bound, some conditions are derived to get two local regions (a smaller and a bigger) such that all the trajectories starting from the smaller region will remain in the bigger one which is required to be contained in a specific compact set (where the original system can be represented as T-S model exactly). In the end, the effectiveness of the proposed results is demonstrated by two examples. © 2013 Elsevier Inc. All rights reserved.

Guo X.,Dalian University of Technology | Zhang Q.,Geodata Engineering
Applied Thermal Engineering | Year: 2013

A new measure of fire size Q′ has been introduced in longitudinally ventilated tunnel as the ratio of flame height to the height of tunnel. The analysis in this article has shown that Q′ controls both the critical velocity and the maximum ceiling temperature in the tunnel. Before the fire flame reaches tunnel ceiling (Q′ < 1.0), Froude number Fr increases with Q′, which is the typical trend of small tunnel fire. Once the flame height exceeds the height of tunnel (Q′ > 1.0), Fr approaches a constant value. This is also a well-known phenomenon in large tunnel fires. Tunnel ceiling temperature shows the opposite trend. Before the fire flame reaches the ceiling, it increases very slowly with the fire size. Once the flame has hit the ceiling of tunnel, temperature rises rapidly with Q′. The good agreement between the current prediction and three different sets of experimental data has demonstrated that the theory has correctly modelled the relation among the heat release rate of fire, ventilation flow and the height of tunnel. From design point of view, the theoretical maximum of critical velocity for a given tunnel can help to prevent oversized ventilation system. © 2013 Elsevier Ltd. All rights reserved.

Lu J.,Liaoning Normal University | Xu L.,Korea Astronomy and Space Science Institute | Xu L.,Dalian University of Technology | Liu M.,Xinyang Normal University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

Kinematical models are constrained by the latest observational data from geometry-distance measurements, which include 557 type Ia supernovae (SNIa) Union2 data and 15 observational Hubble data. Considering two parameterized deceleration parameter, the values of current deceleration parameter q0, jerk parameter j0 and transition redshift zT, are obtained. Furthermore, we show the departures for two parameterized kinematical models from ΛCDM model according to the evolutions of jerk parameter j(z). Also, it is shown that the constraint on jerk parameter j(z) is weak by the current geometrical observed data. © 2011 Elsevier B.V.

Huang H.,University of Texas Southwestern Medical Center | Fan X.,Dalian University of Technology | Williamson D.E.,University of Texas Health Science Center at San Antonio | Rao U.,Southwestern Medical Center
Neuropsychopharmacology | Year: 2011

Alterations in white matter integrity of several cortical and subcortical circuits have been reported in relation to unipolar major depressive disorder. It is not clear whether these white matter changes precede the onset of illness. In all, 13 adolescent volunteers with no personal or family history of a psychiatric disorder (controls) and 18 adolescent volunteers with no personal history of a psychiatric illness including depression, but who were at high risk for developing unipolar depression by virtue of parental depression (high-risk youth), underwent diffusion tensor imaging studies. An automated tract-based spatial statistics method, a whole-brain voxel-by-voxel analysis, was used to analyze the scans. Population average diffusion parameter values were also calculated for each tract. Adolescents at high risk for unipolar depression had lower fractional anisotropy (FA) values in the left cingulum, splenium of the corpus callosum, superior longitudinal fasciculi, uncinate, and inferior fronto-occipital fasciculi than did controls. Altered white matter integrity in healthy adolescents at familial risk for unipolar depression suggests that it might serve as a vulnerability marker for the illness. © 2011 American College of Neuropsychopharmacology. All rights reserved.

Han F.-S.,CAS Changchun Institute of Applied Chemistry | Han F.-S.,Dalian University of Technology
Chemical Society Reviews | Year: 2013

In the transition-metal-catalyzed cross-coupling reactions, the use of the first row transition metals as catalysts is much more appealing than the precious metals owing to the apparent advantages such as cheapness and earth abundance. Within the last two decades, particularly the last five years, explosive interests have been focused on the nickel-catalyzed Suzuki-Miyaura reactions. This has greatly advanced the chemistry of transition-metal-catalyzed cross-coupling reactions. Most notably, a broad range of aryl electrophiles such as phenols, aryl ethers, esters, carbonates, carbamates, sulfamates, phosphates, phosphoramides, phosphonium salts, and fluorides, as well as various alkyl electrophiles, which are conventionally challenging, by applying palladium catalysts can now be coupled efficiently with boron reagents in the presence of nickel catalysts. In this review, we would like to summarize the progress in this reaction. © 2013 The Royal Society of Chemistry.

Pacheco-Torgal F.,University of Minho | Miraldo S.,University of Aveiro | Ding Y.,Dalian University of Technology | Labrincha J.A.,University of Aveiro
Construction and Building Materials | Year: 2013

According to the 2011 ERMCO statistics only a mere 11% of the ready-mixed concrete class production relates to the HPC target, furthermore, this percentage remains unchanged at least since the year 2001. This represents a strange option from the construction industry since HPC offers several advantages over normal-strength concrete, namely, high strength and high durability. Therefore, HPC allows for concrete structures with less steel reinforcement and a longer service life, both of which are crucial issues in the eco-efficiency of construction materials. Although nanotechnology is a very hot issue the fact is that investigations on the field of concrete with nanoparticles are rare (100 in 10,000 Scopus concrete related articles published in the last decade). Actually, it remains to be seen how this research area will contribute to concrete eco-efficiency. This paper summarizes current knowledge on the field of concrete containing nanoparticles. It includes the influence of nanoparticles on the mechanical properties of concrete and on its durability. It also includes calcium leaching control. Moreover, the problem of efficient dispersion of nanoparticles is analyzed. © 2012 Elsevier Ltd. All rights reserved.

A one-step method was reported for the synthesis of 6-acetamido-3-(N-(2- (dimethylamino) ethyl) sulfamoyl) naphthalene-1-yl 7-acetamido-4- hydroxynaphthalene-2-sulfonate by treating 7-acetamido-4-hydroxy-2- naphthalenesulfonyl chloride with equal moles of N, N-dimethylethylenediamine in acetonitrile in the presence of K2CO3. The chemical structure of the obtained compounds was characterized by MS, FTIR, 1H NMR, 13C NMR, gCOSY, TOCSY, gHSQC, and gHMBC. The chemical shift differences of 1H and 13C being δ 0.04 and 0.2, respectively, were unambiguously differentiated. Copyright © 2013 John Wiley & Sons, Ltd. 6-Acetamido-3-(N-(2-(dimethylamino) ethyl) sulfamoyl) naphthalene-1-yl 7-acetamido-4-hydroxynaphthalene-2-sulfonate was prepared by a one-step method. The structure of the compound was elucidated by 1D and 2D NMR. The chemical shift differences of 1H and 13C being δ 0.04 and 0.2, respectively, were unambiguously differentiated. Copyright © 2013 John Wiley & Sons, Ltd.

Wang R.,CAS Yantai Institute of Coastal Zone Research | Yu F.,Dalian University of Technology | Liu P.,CAS Yantai Institute of Coastal Zone Research | Chen L.,CAS Yantai Institute of Coastal Zone Research
Chemical Communications | Year: 2012

We have described a turn on fluorescent probe BOD-NHOH based on hydroxylamine oxidation for detecting intracellular ferric ions. The probe comprises a signal transducer of BODIPY dye and a Fe 3+-response modulator of hydroxylamine. It is readily employed for assessing intracellular ferric ion levels, and confocal imaging is achieved successfully. © 2012 The Royal Society of Chemistry.

Jin T.,Tohoku University | Zhao J.,Tohoku University | Asao N.,Tohoku University | Yamamoto Y.,Tohoku University | Yamamoto Y.,Dalian University of Technology
Chemistry - A European Journal | Year: 2014

The progress of the metal-catalyzed annulation reactions toward construction of various π-conjugated polycyclic cores with high conjugation extension is described. This article gives a brief overview of various annulation reactions promoted by metal catalysts including C-H bond functionalization, [2+2+2] cycloaddition, cascade processes, ring closing metathesis, electrophilic aromatization, and various cross-coupling reactions. A variety of conjugated polycycles with planar, bowl-shaped, and helical structures have been constructed in high efficiency and selectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ming Y.,Dalian University of Technology
Advances in Information Sciences and Service Sciences | Year: 2012

Flooding-based DDoS attacks is a very common way to attack a victim machine by directly or indirectly sending a large amount of malicious traffic to it. Stochastic Fairness Queueing (SFQ) is a typical implementation of Fair Queueing. This paper focuses on exploring the feasibility of mitigating flooding-based DDoS attacks by queueing disciplines. A comparative study is made between SFQ and FCFS (First Come First Served) on their efficacy and robustness in mitigating UDP flooding, a typical flooding-based DDoS attack. Simulation results based on Network Simulator 2 show FCFS has little effect on mitigating UDP flooding while SFQ is more effective and more robust.

Shang H.,Dalian University of Technology
Advances in Information Sciences and Service Sciences | Year: 2012

With the high dynamic development of knowledge economy, the outflow of talent do great damage to many companies. Thus the issue how to attract talented personnel, to reduce the brain drain and retain the talent, has become an important problem facing to each enterprise have to concern. The theory of human resources niche is applied in this paper to do research on the talent environment factors. These factors cause the outflow of talent phenomenon. We study on the impact factors from four aspects through questionnaire analysis, and put forward the corresponding countermeasures.

Feyen M.,Max-Planck-Institut fur Kohlenforschung | Weidenthaler C.,Max-Planck-Institut fur Kohlenforschung | Schuth F.,Max-Planck-Institut fur Kohlenforschung | Lu A.-H.,Dalian University of Technology
Journal of the American Chemical Society | Year: 2010

In this study, a facile and controllable synthetic route for the fabrication of mushroom nanostructures (Fe xO y@PSD-SiO 2) and their hollow derivatives has been established. The synthesis consists of partial coating of Fe xO y (Fe 3O 4 or Fe 2O 3) with polymer spheres, followed by attaching silica hemispheres. The surface-accessible Fe xO y nanoparticles on the Janus-type Fe xO y@PSD nanospheres are key for directing the growth of the silica hemisphere on the Fe xO y@PSD seeds. The size and the porosity of the silica hemispheres are tunable by adjusting the amount of TEOS used and addition of a proper surfactant in a Stöber-type process. After the iron oxide cores were leached out with concentrated HCl, mushroom nanostructures with hollow interiors were obtained, where the morphology of the hollow interior faithfully replicates the shape of the iron oxide core previously filling this void. This synthetic strategy provides a controllable method for the large-scale preparation of asymmetric colloidal nanostructures which could serve as building blocks for the assembly of new types of nanostructures. © 2010 American Chemical Society.

Duan L.,KTH Royal Institute of Technology | Bozoglian F.,Institute of Chemical Research of Catalonia | Mandal S.,Institute of Chemical Research of Catalonia | Stewart B.,University of Stockholm | And 5 more authors.
Nature Chemistry | Year: 2012

Across chemical disciplines, an interest in developing artificial water splitting to O 2 and H 2, driven by sunlight, has been motivated by the need for practical and environmentally friendly power generation without the consumption of fossil fuels. The central issue in light-driven water splitting is the efficiency of the water oxidation, which in the best-known catalysts falls short of the desired level by approximately two orders of magnitude. Here, we show that it is possible to close that 'two orders of magnitude' gap with a rationally designed molecular catalyst [Ru(bda)(isoq) 2] (H 2 bda = 2,2'-bipyridine-6,6'- dicarboxylic acid; isoq = isoquinoline). This speeds up the water oxidation to an unprecedentedly high reaction rate with a turnover frequency of >300 s -1. This value is, for the first time, moderately comparable with the reaction rate of 100-400s -1 of the oxygen-evolving complex of photosystem II in vivo. © 2012 Macmillan Publishers Limited. All rights reserved.

Wang H.,Dalian University of Technology
International Journal of Advancements in Computing Technology | Year: 2011

Due to development and extension of city, we propose an extended city intelligent transportation system based on new concept: transport priority schemes and emergency response scheme. In this paper, we propose an extended collaborative traffic information collection, fusion and storage framework for city intelligent transportation system based on wireless sensor technology. The proposed framework not only solved data fusion and storage problem in transport priority schemes and emergency response scheme, but also has higher reliability and flexibility compare with the traditional city intelligent transportation system.

Lim C.W.,City University of Hong Kong | Xu X.S.,Dalian University of Technology
Applied Mechanics Reviews | Year: 2010

Many of the early works on symplectic elasticity were published in Chinese and as a result, the early works have been unavailable and unknown to researchers worldwide. It is the main objective of this paper to highlight the contributions of researchers from this part of the world and to disseminate the technical knowledge and innovation of the symplectic approach in analytic elasticity and applied engineering mechanics. This paper begins with the history and background of the symplectic approach in theoretical physics and classical mechanics and subsequently discusses the many numerical and analytical works and papers in symplectic elasticity. This paper ends with a brief introduction of the symplectic methodology. A total of more than 150 technical papers since the middle of 1980s have been collected and discussed according to various criteria. In general, the symplectic elasticity approach is a new concept and solution methodology in elasticity and applied mechanics based on the Hamiltonian principle with Legendre's transformation. The superiority of this symplectic approach with respect to the classical approach is at least threefold: (i) it alters the classical practice and solution technique using the semi-inverse approach with trial functions such as those of Navier, Ĺvy, and Timoshenko; (ii) it consolidates the many seemingly scattered and unrelated solutions of rigid body movement and elastic deformation by mapping with a series of zero and nonzero eigenvalues and their associated eigenvectors; and (iii) the Saint-Venant problems for plane elasticity and elastic cylinders can be described in a new system of equations and solved. A unique feature of this method is that bending of plate becomes an eigenvalue problem and vibration becomes a multiple eigenvalue problem. © 2010 American Society of Mechanical Engineers.

Zhang L.,Dalian University of Technology | Jahng D.,Myongji University
Waste Management | Year: 2012

The purpose of this study was to examine if long-term anaerobic digestion of food waste in a semi-continuous single-stage reactor could be stabilized by supplementing trace elements. Contrary to the failure of anaerobic digestion of food waste alone, stable anaerobic digestion of food waste was achieved for 368days by supplementing trace elements. Under the conditions of OLR (organic loading rates) of 2.19-6.64g VS (volatile solid)/Lday and 20-30days of HRT (hydraulic retention time), a high methane yield (352-450mLCH 4/gVS added) was obtained, and no significant accumulation of volatile fatty acids was observed. The subsequent investigation on effects of individual trace elements (Co, Fe, Mo and Ni) showed that iron was essential for maintaining stable methane production. These results proved that the food waste used in this study was deficient in trace elements. © 2012.

Tong L.,KTH Royal Institute of Technology | Duan L.,KTH Royal Institute of Technology | Xu Y.,Dalian University of Technology | Privalov T.,University of Stockholm | Sun L.,KTH Royal Institute of Technology
Angewandte Chemie - International Edition | Year: 2011

Small change, big difference: A minor structural modification of water-oxidation catalysts changes the kinetics of O2 evolution from second- to first-order (see scheme). According to DFT calculations, the torsional flexibility of the chelating ligands and their reorganization through the catalytic cycle are implicated in pathway selectivity, and the auxiliary carboxylate group becomes involved in proton-coupled nucleophilic attack. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li X.,Henan University | Mao L.,Henan University | Ma X.,Dalian University of Technology
Langmuir | Year: 2013

Textured silicon surfaces decorated by square arrays of pillars with adjustable pitch were fabricated. The wetting behavior, especially for direction-dependent water contact angles on textured silicon surfaces after silanization, was investigated by incorporating the contact line fraction into a modified Wenzel model. Also, the effect of geometrical parameters on the anisotropic wetting behavior of water was examined with respect to water droplet impact on the textured surface. Moreover, the maximum spreading factor was studied theoretically in terms of energy conservation, allowing for surface topography and viscous friction of the liquid flowing among the arrays of the posts. Theoretical models were found to be in good agreement with experimental data. © 2012 American Chemical Society.

Sun H.,Dalian University of Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

In this paper, we investigate the γp photoproduction of jet plus missing energy signal to set limits on the couplings of the fermionic dark matter to the quarks at the LHC via the main reaction pp→pγp→ pχχj. We assume typical LHC multipurpose forward detectors and work in a model independent effective field theory framework. Typically, when we do the background analysis, we also include their corresponding single diffractive productions. Our result shows that by requiring a 5σ (S/B≥5) signal deviation, with an integrated luminosity of L=200fb-1, the lower bounds of the weakly interacting massive particle masses scale can be detected up to Λ equal to 665.5, 808.9, and 564.0 GeV for the forward detector acceptances ξ1, ξ2, and ξ3, respectively, where 0.0015<ξ1<0.5, 0.1<ξ2<0.5 and 0.0015<ξ3<0.15. © 2014 American Physical Society.

Yao R.,Dalian University of Technology | Yao R.,University of California at Davis
Journal of Advanced Transportation | Year: 2013

Short left-turn lanes are often channelized to improve capacity and level of service at signalized intersections. On the basis of previous achievements, this paper improves the joint optimization models for isolated signalized intersections with short left-turn lanes and aims to analyze the sensitivity of the optimization results to the parameters (critical cycle length and maximum short-lane length). To further clarify the effects of these models on traffic flow operations, several better optimization scenarios are simulated together with the existing one. The models and the methods are illustrated via the field data from Dalian, China. According to the analysis results, the optimum models and parameter values or ranges are recommended. Finally, the procedure of the model application is also proposed to apply in practice. Copyright © 2012 John Wiley & Sons, Ltd.

Wang L.,Dalian University of Technology
Bioprocess and Biosystems Engineering | Year: 2013

Understanding the transport mechanism of 1,3-propanediol (1,3-PD) is of critical importance to do further research on gene regulation. Due to the lack of intracellular information, on the basis of enzyme-catalytic system, using biological robustness as performance index, we present a system identification model to infer the most possible transport mechanism of 1,3-PD, in which the performance index consists of the relative error of the extracellular substance concentrations and biological robustness of the intracellular substance concentrations. We will not use a Boolean framework but prefer a model description based on ordinary differential equations. Among other advantages, this also facilitates the robustness analysis, which is the main goal of this paper. An algorithm is constructed to seek the solution of the identification model. Numerical results show that the most possible transport way is active transport coupled with passive diffusion. © 2012 Springer-Verlag.

Shen Y.,Huazhong University of Science and Technology | Wang J.,Huazhong University of Science and Technology | Wang J.,Chinese University of Hong Kong | Wang J.,Dalian University of Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2012

In recent years, the global stability of recurrent neural networks (RNNs) has been investigated extensively. It is well known that time delays and external disturbances can derail the stability of RNNs. In this paper, we analyze the robustness of global stability of RNNs subject to time delays and random disturbances. Given a globally exponentially stable neural network, the problem to be addressed here is how much time delay and noise the RNN can withstand to be globally exponentially stable in the presence of delay and noise. The upper bounds of the time delay and noise intensity are characterized by using transcendental equations for the RNNs to sustain global exponential stability. Moreover, we prove theoretically that, for any globally exponentially stable RNNs, if additive noises and time delays are smaller than the derived lower bounds arrived at here, then the perturbed RNNs are guaranteed to also be globally exponentially stable. Three numerical examples are provided to substantiate the theoretical results. © 2012 IEEE.

He R.,CAS Institute of Automation | Zheng W.-S.,Sun Yat Sen University | Hu B.-G.,CAS Institute of Automation | Kong X.-W.,Dalian University of Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

This paper proposes a novel nonnegative sparse representation approach, called two-stage sparse representation (TSR), for robust face recognition on a large-scale database. Based on the divide and conquer strategy, TSR decomposes the procedure of robust face recognition into outlier detection stage and recognition stage. In the first stage, we propose a general multisubspace framework to learn a robust metric in which noise and outliers in image pixels are detected. Potential loss functions, including L1, L 2,1, and correntropy are studied. In the second stage, based on the learned metric and collaborative representation, we propose an efficient nonnegative sparse representation algorithm to find an approximation solution of sparse representation. According to the L1 ball theory in sparse representation, the approximated solution is unique and can be optimized efficiently. Then a filtering strategy is developed to avoid the computation of the sparse representation on the whole large-scale dataset. Moreover, theoretical analysis also gives the necessary condition for nonnegative least squares technique to find a sparse solution. Extensive experiments on several public databases have demonstrated that the proposed TSR approach, in general, achieves better classification accuracy than the state-of-the-art sparse representation methods. More importantly, a significant reduction of computational costs is reached in comparison with sparse representation classifier; this enables the TSR to be more suitable for robust face recognition on a large-scale dataset. © 2012 IEEE.

Zhang L.,Dalian University of Technology | Zhang L.,Myongji University | Lee Y.-W.,Hanyang University | Jahng D.,Myongji University
Journal of Hazardous Materials | Year: 2012

In this study, the effects of ammonia removal by air stripping as a pretreatment on the anaerobic digestion of piggery wastewater were investigated. Ammonia stripping results indicated that ammonia removal was strongly dependent on pH and aeration rate, and the ammonia removal rate followed the pseudo-first-order kinetics. A significant enhancement of biomethanization was observed for wastewaters of which ammonia was air-stripped at pH 9.5 and pH 10.0. The methane productivity increased from 0.23±0.08L CH 4/Ld of the control (raw piggery wastewater) to 0.75±0.11L CH 4/Ld (ammonia-stripped at pH 9.5) and 0.57±0.04L CH 4/Ld (ammonia-stripped at pH 10.0). However, the improvement of methane production from the piggery wastewater pretreated at pH 11.0 was negligible compared to the control, which was thought to be due to the high concentration of sodium ions supplied from sodium hydroxide for pH adjustment. From these results, it was concluded that ammonia removal through air stripping at the alkaline pH could be a viable option for preventing the failure of anaerobic digestion of the raw piggery wastewater. Additionally, it was also found that a high concentration of sodium ion originated from sodium hydroxide for pH adjustment inhibited methane production. © 2011 Elsevier B.V.

Wu M.,Hebei Normal University | Ma T.,Dalian University of Technology | Ma T.,Kyushu Institute of Technology
Journal of Physical Chemistry C | Year: 2014

To realize long-term developments and practical application of the dye-sensitized solar cells (DSCs) requires a robust increase of the power conversion efficiency (PCE) and a significant decrease of the production cost. Fortunately, a new record PCE value of 12.3% was achieved by using cobalt-based redox couples combined with organic dye. Evidently, dye design is the key path to improve the PCE, while developing low cost counter electrode (CE) catalysts is one of the promising paths to reduce the production cost of DSCs by replacing the expensive Pt CE. In this article, we review the recent progress of CE catalysts involving Pt, carbon materials, inorganic materials, multiple compounds, polymers, and composites. We discuss the advantages and disadvantages of each catalyst and put forward ideas for designing new CE catalysts in future research for DSCs and other application fields. © 2014 American Chemical Society.

Wang H.,Jiangsu University | Li J.,Dalian University of Technology
Gaodianya Jishu/High Voltage Engineering | Year: 2013

In order to testify the important effect of hydroxyl radicals (·OH) on organic compounds degradation during a pulsed discharge process in aqueous system, by choosing phenol as a target pollutant, the degradation rates of phenol and the energy efficiencies of reaction system were reviewed under different additive collectors when air and O2 were used as bubbling gas, respectively. Under the same experimental conditions, the concentrations of H2O2 produced by pulsed discharge in deionized water were also measured. The experimental results showed that, in the carrier gases of air and O2, the degradation rates of phenol and the energy efficiencies of phenol decreased with the increase of the concentration of addition (both Na2CO3 and n-butanol) during a pulsed discharge process. And the important effect of ·OH on organic compounds degradation in the pulsed discharge plasma system was testified. Furthermore, the measurement results of H2O2 proved the collecting effect of collectors on ·OH.

Zhang C.,State Key Laboratory of Fine Chemicals | Zhao J.,State Key Laboratory of Fine Chemicals | Wu S.,Dalian University of Technology | Wang Z.,State Key Laboratory of Fine Chemicals | And 4 more authors.
Journal of the American Chemical Society | Year: 2013

Resonance energy transfer (RET) was used for the first time to enhance the visible light absorption of triplet photosensitizers. The intramolecular energy donor (boron-dipyrromethene, Bodipy) and acceptor (iodo-Bodipy) show different absorption bands in visible region, thus the visible absorption was enhanced as compared to the monochromophore triplet photosensitizers (e.g., iodo-Bodipy). Fluorescence quenching and excitation spectra indicate that the singlet energy transfer is efficient for the dyad triplet photosensitizers. Nanosecond time-resolved transient absorption spectroscopy has confirmed that the triplet excited states of the dyads are distributed on both the energy donor and acceptor, which is the result of forward singlet energy transfer from the energy donor to the energy acceptor and in turn the backward triplet energy transfer. This 'ping-pong' energy transfer was never reported for organic molecular arrays, and so it is useful to study the energy level of organic chromophores. The triplet photosensitizers were used for singlet oxygen (1O 2) mediated photooxidation of 1,5-dihydroxylnaphthalene to produce juglone. The visible light absorption of the new visible light-absorbing triplet photosensitizers are higher than the conventional monochromophore based triplet photosensitizers, as a result, the 1O2 photosensitizing ability is improved with the new triplet photosensitizers. Triplet-triplet annihilation upconversion with these triplet photosensitizers was also studied. Our results are useful to design the triplet photosensitizers showing strong visible light absorbance and for their applications in photocatalysis and photodynamic therapy. © 2013 American Chemical Society.

Zhou Y.,University of Paris Descartes | Zhou Y.,Dalian University of Technology | Lecourt T.,University of Paris Descartes | Micouin L.,University of Paris Descartes
Angewandte Chemie - International Edition | Year: 2010

"Chemical Equation Presented" Al together now: Aluminotriazoles are obtained in a fully chemo- and regioselective manner by a copper-catalyzed cycloaddition of organic azides with mixed-aluminum acetylides (see scheme). The carbon-aluminum bond, which is unaffected by the first transformation, is still able to react further with different electrophiles. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Liu Y.-J.,Liaoning University of Technology | Wang W.,Dalian University of Technology
International Journal of Robust and Nonlinear Control | Year: 2012

An adaptive output feedback control approach is studied for a class of uncertain nonlinear systems in the parametric output feedback form. Unlike the previous works on the adaptive output feedback control, the problem of 'explosion of complexity' of the controller in the conventional backstepping design is overcome in this paper by introducing the dynamic surface control (DSC) technique. In the previous schemes for the DSC technique, the time derivative for the virtual controllers is assumed to be bounded. In this paper, this assumption is removed. It can be proven that the resulting closed-loop system is stable in the sense that all the signals are semi-global uniformly ultimately bounded and the system output tracks the reference signal to a bounded compact set. A simulation example is given to verify the effectiveness of the proposed approach. Copyright © 2011 John Wiley & Sons, Ltd.

Wang J.-B.,Shenyang Aerospace University | Wang J.-J.,Dalian University of Technology
Information Sciences | Year: 2014

In this paper we investigate a single machine scheduling problem with time dependent processing times and group technology (GT) assumption. By time dependent processing times and group technology assumption, we mean that the group setup times and job processing times are both increasing functions of their starting times, i.e., group setup times and job processing times are both described by function which is proportional to a linear function of time. We attempt to minimize the makespan with ready times of the jobs. We show that the problem can be solved in polynomial time when start time dependent processing times and group technology are considered simultaneously. © 2014 Elsevier Inc. All rights reserved.

Sun J.,Dalian University of Technology
Bioresource technology | Year: 2012

In this study the feasibility of preparing bioflocculant from excess biological sludge was investigated. Hydrochloric acid was used to disintegrate sludge to prepare bioflocculant. The effects of acid dosage and flocculating conditions were studied. The optimized disintegration conditions was that acid dosage was 10 mL for 50 mL sludge suspension. Factors such as bioflocculant dosage, pH and temperature of the flocculant system were also tested. The optimal conditions were flocculant concentration 3.0% (v/v) and pH10.5 of flocculating suspension. Under these conditions, 99.5% of flocculating rate for 4 g/L kaolin clay was achieved. Ethanol and sodium hydroxide were applied to purify the crude sludge bioflocculant together or separately. Results showed that sodium hydroxide could separate the bioflocculant from aqueous solution more effectively than ethanol. Analysis of the purified bioflocculant by Fourier-transform infrared spectrophotometer (FT-IR) and chemical methods indicated that the main component was polysaccharide. Performance test showed that the sludge bioflocculant had moderate thermostability. Copyright © 2012 Elsevier Ltd. All rights reserved.

Huang X.L.,Liaoning Normal University | Wang T.,Liaoning Normal University | Yi X.X.,Dalian University of Technology
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

We establish a quantum Otto engine cycle in which the working substance contacts with squeezed reservoirs during the two quantum isochoric processes. We consider two working substances: (1) a qubit and (2) two coupled qubits. Due to the effects of squeezing, the working substance can be heated to a higher effective temperature, which leads to many interesting features different from the ordinary ones, such as (1) for the qubit as working substance, if we choose the squeezed parameters properly, the positive work can be exported even when T H

Duan L.,KTH Royal Institute of Technology | Xu Y.,KTH Royal Institute of Technology | Tong L.,KTH Royal Institute of Technology | Sun L.,KTH Royal Institute of Technology | Sun L.,Dalian University of Technology
ChemSusChem | Year: 2011

A series of mononuclear ruthenium polypyridyl complexes [Ru(Mebimpy)(pic)3](PF6)2 (2; Mebimpy=2,6-bis(1-methylbenzimidazol-2-yl)pyridine; pic=4-picoline), Ru(bimpy)(pic)3 (3; H2bimpy=2,6-bis(benzimidazol-2-yl) pyridine), trans-[Ru(terpy)(pic)2Cl](PF6) (4; terpy=2,2′;6′,2"-terpyridine), and trans-[Ru(terpy)(pic) 2(OH2)](ClO4)2 (5) are synthesized and characterized as analogues of the known Ru complex, [Ru(terpy)(pic) 3](PF6)2 (1). The effect of the ligands on electronic and catalytic properties is studied and discussed. The negatively charged ligand, bimpy2-, has a remarkable influence on the electrochemical events due to its strong electron-donating ability. The performance in light- and CeIV-driven (CeIV=Ce(NH 4)2(NO3)6) water oxidation is successfully demonstrated. We propose that ligand exchange between pic and H2O occurs to form the real catalyst, a Ru-aqua complex. The synthesis and testing of trans-[Ru(terpy)(pic)2(OH 2)](ClO4)2 (5) confirmed our proposal. In addition, complex 5 possesses the best catalytic activity among these five complexes. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luo Y.,Northwestern Polytechnical University | Li A.,University of Reims | Kang Z.,Dalian University of Technology
Engineering Structures | Year: 2011

It is meaningful to account for various uncertainties in the optimization design of the adhesive bonded steel-concrete composite beam. Based on the definition of the mixed reliability index for structural safety evaluation with probabilistic and non-probabilistic uncertainties, the reliability-based optimization incorporating such mixed reliability constraints are mathematically formulated as a nested problem. The performance measure approach is employed to improve the convergence and the stability in solving the inner-loop. Moreover, the double-loop optimization problem is transformed into a series of approximate deterministic problems by incorporating the sequential approximate programming and the iteration scheme, which greatly reduces the burdensome computation workloads in seeking the optimal design. The validity of the proposed formulation as well as the efficiency of the presented numerical techniques is demonstrated by a mathematical example. Finally, reliability-based optimization designs of a single span adhesive bonded steel-concrete composite beam with different loading cases are achieved through integrating the present systematic method, the finite element analysis and the optimization package. © 2011 Elsevier Ltd.

Lv W.,Dalian University of Technology
Chemical Physics Letters | Year: 2011

We report the molecular dynamics simulations of the adsorption of DNA bases on (8, 8) carbon nanotubes (CNTs) in solvent environment. The adsorption processes of bases on neutral and charged CNTs have been observed. Results show that bases can rapidly adsorb on the sidewall of neutral CNTs due to the van der Walls interaction. But the binding geometries of the bases-CNT change with the charge density of CNT, bases no longer stack on highly charged nanotube surfaces. The competition between polarized water and bases results in the instability of the adsorption of DNA based on charged CNTs. © 2011 Elsevier B.V. All rights reserved.

Zhao J.,Harbin Institute of Technology | Wu B.,Harbin Institute of Technology | Ou J.,Harbin Institute of Technology | Ou J.,Dalian University of Technology
Earthquake Engineering and Structural Dynamics | Year: 2011

A novel type of angle steel buckling-restrained brace (ABRB) has been developed for easier control on initial geometric imperfection in the core, more design flexibility in the buckling restraining mechanism and easier assembly work. The steel core is composed of four angle steels to form a non-welded cruciform shape restrained by two external angle steels, which are welded longitudinally to form an external tube. Component test was conducted on seven ABRB specimens under uniaxial quasi-static cyclic loading. The test results reveal that the consistency between the actual and design behavior of ABRB can be well achieved without the effect of weld in the core. The ABRBs with proper details exhibited stable cyclic behavior and satisfactory cumulative plastic ductility capacity, so that they can serve as effective hysteretic dampers. However, compression-flexure failure at the steel core projection was found to be the primary failure mode for the ABRBs with hinge connections even though the cross-section of the core projection was reinforced two times that of the yielding segment. The failure mechanism is further discussed by investigating the Nu- Mu correlation curve. It is found that the bending moment response developed in the core projection induced by end rotation was the main cause for such a failure mode, and it is suggested that core projection should be kept within elastic stage under the possible maximum axial load and bending moment response. © 2010 John Wiley & Sons, Ltd.

Zhao N.,Dalian University of Technology
Wireless Personal Communications | Year: 2013

Spectrum sensing is a key problem in cognitive radio. However, traditional detectors become ineffective when noise uncertainty is severe. It is shown that the entropy of Gauss white noise is constant in the frequency domain, and a robust detector based on the entropy of spectrum amplitude was proposed. In this paper a novel detector is proposed based on the entropy of spectrum power density, and its performance is better than the previous scheme with less computational complexity. Furthermore, to improve the reliability of the detection, a two-stage entropy-based cooperative spectrum sensing scheme using two-bit decision is proposed, and simulation results show its superior performance with relatively low computational complexity. © 2012 Springer Science+Business Media, LLC.

Han M.,Dalian University of Technology
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2012

The performance of an electroencephalography (EEG) automatic detection and classification system mainly depends on the feature extraction of EEG signal. This paper analyses the advantages and disadvantages of the current EEG feature extraction methods, and then presents a new EEG feature extraction method based on echo state networks (ESN). The new method is a nonlinear method, and can extract the EEG features reversibly. Therefore, the information lost in the process of feature extraction is much less than that of the traditional EEG. Additionally, the realization of this method just needs to compute the pseudo inverse of a matrix, which keeps it efficient. Experimental results have showed that the new method could well accomplish the task of automatic detection and classification of EEG signals.

Zhai F.,Zhejiang Normal University | Mu P.,Dalian University of Technology
Applied Physics Letters | Year: 2011

We study the transport properties of Dirac fermions on the surface of a topological insulator attached with a spiral multiferroic oxide (SMO). For the spiral plane of the SMO parallel to the spiral axis and the surface normal, the proximity-induced exchange field causes a particle-hole asymmetry and a transmission gap near the Dirac point. The transmission gap interval depends on the spiral wave vector q. This fact together with the tunability of q by gate voltages indicates an electric switch with high on-off ratios. The dependence of the conductance on the orientation of the spiral plane is also examined. © 2011 American Institute of Physics.

Zhai F.,Zhejiang Normal University | Yang L.,Dalian University of Technology
Applied Physics Letters | Year: 2011

We investigate spin-dependent electronic transport through normal/strained/normal/ferromagnetic/normal graphene junctions. The substrate strain leads to opposite shifts of the K and K′ valleys and thus modulates the orbital motion of Dirac electrons. The energy dependence of this effect together with the exchange splitting can be utilized to design a strain-tunable spin filter. © 2011 American Institute of Physics.

Zhao X.-Q.,Dalian University of Technology
Evidence-based Complementary and Alternative Medicine | Year: 2011

Marine microorganisms are rich source for natural products which play important roles in pharmaceutical industry. Over the past decade, genome-based studies of marine microorganisms have unveiled the tremendous diversity of the producers of natural products and also contributed to the efficiency of harness the strain diversity and chemical diversity, as well as the genetic diversity of marine microorganisms for the rapid discovery and generation of new natural products. In the meantime, genomic information retrieved from marine symbiotic microorganisms can also be employed for the discovery of new medical molecules from yet-unculturable microorganisms. In this paper, the recent progress in the genomic research of marine microorganisms is reviewed; new tools of genome mining as well as the advance in the activation of orphan pathways and metagenomic studies are summarized. Genome-based research of marine microorganisms will maximize the biodiscovery process and solve the problems of supply and sustainability of drug molecules for medical treatments. © 2011 Xin-Qing Zhao.

Zhao M.,Dalian University of Technology
Journal of Hydraulic Research | Year: 2016

Numerical solutions of two quasi-two-dimensional models for water hammer problems under laminar flow conditions are proposed. The solutions are based on modified Chebyshev polynomial expansion of radial distribution of velocities. The collocation method is used to solve for the expansion coefficients. Spatial variation in the axial direction and time advancement are treated using the method of characteristics. One model includes the radial velocity components in the continuity equation while the other is focused on the cross-sectional mean velocity without the radial component. The effect of including the radial velocity component in the flow system is evaluated. The Chebyshev polynomials constitute an orthogonal basis for approximating numerical solutions and show suitable behaviour of the expansion coefficients. © 2016 International Association for Hydro-Environment Engineering and Research

Cao T.,Dalian University of Technology | Cryan M.J.,University of Bristol
Journal of Electromagnetic Waves and Applications | Year: 2012

We investigate the polarization properties of a two-dimensional (2D) array of metallic elliptical nanoholes in the visible wavelength region. The calculated spectra reveal that such a nonchiral structure exhibits a circular dichroism. The proposed structure is a 2D anisotropic system that possesses two principle polarization directions, which gives rise to different polarization modes along long and short diameters of an elliptical nanohole. When the non-chiral elliptical hole forms a chiral arrangement with the off-normal incident wave vector, the two different polarization modes introduce a net polar vector that forms a chiral triad. Therefore, circular dichroism can be observed in a nonchiral elliptical nanohole array. © 2012 Taylor & Francis.

Zhou Y.-T.,Yonsei University | Lee K.Y.,Yonsei University | Lee K.Y.,Dalian University of Technology
International Journal of Solids and Structures | Year: 2012

A theoretical model is developed for the exact contact analysis of magneto-electro-elastic half-plane materials indented by a moving rigid punch in this paper, which is Part I of a series of papers. A numerical analysis based on this theoretical model will be presented in Part II. The Galilean transformation and the Fourier sine and cosine transforms are applied to make the transient problem tractable. Detailed analyses of the eigenvalue distributions of the double-biquadrate order characteristic equation related to the magneto-electro-elastic governing equations are performed. Real fundamental solutions are derived for each eigenvalue distribution. The punch may have a flat or cylindrical profile and may be electrically and magnetically conducting, electrically conducting and magnetically insulating, electrically insulating and magnetically conducting, or electrically and magnetically insulating. For each type of punch, the singular integral equations are derived with the surface contact stress, surface electric charge, and/or surface magnetic induction inside the contact region as the unknown functions. Exact solutions to the system of integral equations are obtained. In particular, closed-form expressions for the stresses, electric displacements, and magnetic inductions in terms of fundamental functions are derived, which provide a scientific basis for the interpretation of the contact behaviors of multiferroic materials as will be shown in Part II of this series of papers. © 2012 Elsevier Ltd. All rights reserved.

Xu Z.,University of Cambridge | Xu Z.,Ewha Womans University | Xu Z.,Dalian University of Technology | Yoon J.,Ewha Womans University | Spring D.R.,University of Cambridge
Chemical Society Reviews | Year: 2010

In the past decade, fluorescent chemosensors for zinc ion (Zn2+) have attracted great attention because of the biological significance of zinc combined with the simplicity and high sensitivity of fluorescence assays. Chemosensors can be divided into a fluorophore, a spacer and a receptor unit; the receptor is the central processing unit (CPU) of a chemosensor. This tutorial review will classify zinc chemosensors based on receptor types. © The Royal Society of Chemistry 2010.

Chen X.,Ewha Womans University | Zhou Y.,Ewha Womans University | Peng X.,Dalian University of Technology | Yoon J.,Ewha Womans University
Chemical Society Reviews | Year: 2010

Due to the biological importances of thiols, such as cysteine, homocysteine and glutathione, the development of optical probes for thiols has been an active research area in recent few years. This critical review focuses on the fluorescent or colorimetric sensors for thiols according to their unique mechanisms between sensors and thiols, including Michael addition, cyclization with aldehyde, cleavage of sulfonamide and sulfonate ester by thiols, cleavage of selenium-nitrogen bond by thiols, cleavage of disulfide by thiols, metal complexes-oxidation-reduction, metal complexes-displace coordination, nano-particles and others (110 references). © The Royal Society of Chemistry 2010.

Li S.,Dalian University of Technology
Journal of Sound and Vibration | Year: 2011

Active modal control simulation of vibro-acoustic response of a fluid-loaded plate is presented. The active modal control of the vibro-acoustic response is implemented using piezoelectric actuators/sensors. The active modal damping is added to the coupled system via negative velocity feedback. The feedback gain between the piezoelectric actuators/sensors for the modal control is obtained using the in-vacuo modal matrix and the incompressible fluid-loaded modal matrix. The modal control performance of structural vibration and acoustic radiation of a baffled plate is numerically studied. It is shown that the proposed method increases the modal damping ratio and achieves reduction in the mean square velocity and the sound power for given modes of the fluid-loaded plate. © 2011 Elsevier Ltd. All rights reserved.

He Z.,Dalian University of Technology | Yu W.,Hong Kong University of Science and Technology
Computational Biology and Chemistry | Year: 2010

Feature selection techniques have been used as the workhorse in biomarker discovery applications for a long time. Surprisingly, the stability of feature selection with respect to sampling variations has long been under-considered. It is only until recently that this issue has received more and more attention. In this article, we review existing stable feature selection methods for biomarker discovery using a generic hierarchical framework. We have two objectives: (1) providing an overview on this new yet fast growing topic for a convenient reference; (2) categorizing existing methods under an expandable framework for future research and development. © 2010 Elsevier Ltd.

Cao X.,Dalian University of Technology | Cao X.,University of Paderborn | Ishida S.,Tokyo University of Science
Nonlinearity | Year: 2014

We consider a degenerate quasilinear Keller-Segel system of fully-parabolic type involving rotation in the aggregative term, ut = ∇ · (∇um - uS(u, v, x)∇v), (x, t) ∈ Ω × (0, T ), vt = Δv - uv, (x, t) ∈ Ω × (0, T ), ∇v · ν = 0, (∇um - uS(u, v, x)∇v) · ν = 0, x ∈ ∂Ω, t > 0 where Ω ⊂ ℝ2 is a bounded convex domain with smooth boundary. Here S(u, v, x) = (si,j)2×2 is a matrix with s i,j ∈ C1([0,∞) × [0,∞) × Ω). Moreover, |S(u, v, x)| < S̃(v) for all (u, v, x) ∈ [0,∞) × [0,∞) × Ω with S̃(v) nondecreasing on [0,∞). It is shown that whenever m > 1, for any nonnegative initial data, which is sufficiently smooth, the system possesses global and bounded weak solution. © 2014 IOP Publishing Ltd & London Mathematical Society.

Hsieh C.-W.,National Sun Yat - sen University | Zheng B.,Dalian University of Technology | Hsieh S.,National Sun Yat - sen University
Chemical Communications | Year: 2010

Magnetic force microscopy was used to image and detect ferritin proteins and the strength of the magnetic signal is discussed, revealing a large workable lift height between the magnetic tip and the ferritin sample. © 2010 The Royal Society of Chemistry.

Liu Q.,Nanjing Southeast University | Wang J.,Chinese University of Hong Kong | Wang J.,Dalian University of Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

This paper presents a one-layer projection neural network for solving nonsmooth optimization problems with generalized convex objective functions and subject to linear equalities and bound constraints. The proposed neural network is designed based on two projection operators: linear equality constraints, and bound constraints. The objective function in the optimization problem can be any nonsmooth function which is not restricted to be convex but is required to be convex (pseudoconvex) on a set defined by the constraints. Compared with existing recurrent neural networks for nonsmooth optimization, the proposed model does not have any design parameter, which is more convenient for design and implementation. It is proved that the output variables of the proposed neural network are globally convergent to the optimal solutions provided that the objective function is at least pseudoconvex. Simulation results of numerical examples are discussed to demonstrate the effectiveness and characteristics of the proposed neural network. © 2013 IEEE.

Li M.,Dalian University of Technology | Li M.,Newcastle University | Scott K.,Newcastle University
Journal of Power Sources | Year: 2011

A polytetrafluoroethylene (PTFE)/quaternized polysulfone (QNPSU) composite membrane has been fabricated for use in proton exchange membrane fuel cells (PEMFCs). The composite membrane is made by immobilizing a QNPSU solution into a hydrophobic porous PTFE membrane. The structure of the composite membrane is examined by SEM and EDX. The ionic conductivity of the PTFE/QNPSU membrane, at a relative humidity lower than 0.5% and a temperature of 180 °C, is greater than 0.3 S cm-1, when loaded with 400% H3PO4. A hydrogen fuel cell with this membrane operating at 2.0 atmosphere absolute (atma) pressure and 175 °C gives voltages >0.4 V at current densities of 1.0 A cm-2 using oxygen. © 2010 Elsevier B.V.

Meng X.,Tianjin University | Jia M.,Dalian University of Technology | Wang T.,Tianjin University
Fuel | Year: 2014

Viscosity is an important fluid property because of its direct relation with the fuel injection process for engines. The kinematic viscosity of biodiesel at 313 K should satisfy the range specified by the international biodiesel standards. In this study, an artificial neural network (ANN) method was developed to predict the biodiesel kinematic viscosity at 313 K with the experimental data of 105 biodiesel samples collected from the literature. The ANN method only uses the mass fractions of 19 fatty acid methyl esters (FAMEs) as inputs, which avoids the need of the kinematic viscosities of the individual FAMEs required by the prediction methods using the mixing equations. Two previously reported methods based on empirical equations, the Knothe-Steidley method with the experimental or predicted (when experimental data are unavailable) viscosities of FAMEs as inputs and the Ramírez-Verduzco method with the predicted viscosities of FAMEs as inputs were also extensively evaluated to compare with the proposed ANN method. Results indicate that the proposed ANN method is able to predict overall more accurate biodiesel kinematic viscosities at 313 K with the mean squared error (MSE) of 0.0099 compared with the Knothe-Steidley method and the Ramírez-Verduzco method. In most cases, both the Knothe-Steidley method and the Ramírez-Verduzco method tend to under-predict the kinematic viscosities. The underestimation might be attributed to the viscosity contributions of minor mono-, di- and triacylglycerols resulting from incomplete transesterification and minor or trace amount of other FAMEs to the experimental viscosities, as well as the neglect of the interactions between the individual components in calculation of the mixture kinematic viscosities. However, the ANN method could learn to account for the viscosity contributions from the minor components and the interactions between the individual components to some extent during the training process. Overall, the ANN method realizes the best accuracy for the prediction of biodiesel kinematic viscosity with the highest correlation coefficient of 0.9774. © 2013 Elsevier Ltd. All rights reserved.

Tang B.,Dalian University of Technology | Brennan M.J.,Sao Paulo State University
International Journal of Mechanical Sciences | Year: 2014

The vibration isolation characteristics of a high-static-low-dynamic- stiffness (HSLDS) isolator, which has geometrically nonlinear stiffness, have been well established both theoretically and experimentally in the recent literature. However, the shock isolation characteristics of such an isolator subject to base excitation are not currently known. In this paper, these characteristics are determined for two illustrative inputs, which are a rounded step and a versed sine displacement, using a simple model of the isolator comprising a vertical spring coupled to two horizontal springs. The isolator is configured to reduce the dynamic stiffness of the isolator and hence increase the frequency range of isolation. The shock responses of the isolator are determined analytically for low levels of excitation, and numerically for high levels of excitation. It is found that when the shock amplitude is small, the nonlinearity is beneficial, and that the quasi-zero stiffness isolator has the best shock performance in terms of the smallest displacement and acceleration of the suspended mass. © 2014 Elsevier Ltd.

Qiao F.,Jiangsu University | Sang Y.-C.,Dalian University of Technology
Vacuum | Year: 2014

Densely packed and highly ordered CdSe quantum dots (QDs) arrays were prepared through a slow evaporation route; to study the photo-generated charges property of ordered CdSe QDs arrays, illumination induced charge separation in the CdSe QDs arrays were investigated through surface photovoltage (SPV) technology based on lock in amplifier. The significantly enhanced SPV signal of CdSe QDs arrays after post-annealing treatment could be attributed to the greatly increased escape of holes from CdSe QDs surface, as well as the decreased the inter nanocrystal distance. Moreover, much faster excess holes dominates in the frequency range of 30 Hz and 200 Hz, which results in the positive charging of the CdSe QDs arrays near the surface. Our results give a guide for its practical photoelectric applications based on nanocrystals. © 2013 Elsevier Ltd. All rights reserved.

Wang W.,Guangdong Ocean University | Li F.,Dalian University of Technology
Optics and Lasers in Engineering | Year: 2014

We propose an efficient approach to develop large-range liquid level sensors based on an extrinsic Fabry-Perot optical fibre interferometer with an all fused-silica structure and CO2 laser heating fusion bonding technology. The sensor exhibits signatures of a high sensitivity of 5.3 nm/kPa (36.6 nm/psi), a resolution of 6.8 Pa (9.9×10-4 psi) and an extreme low temperature dependence of 0.013 nm/ C. As a result, a high resolution of the water level measurement of approximately 0.7 mm on the length scale of 5 m and small errors of the water pressure measurement induced by the temperature dependence within 0.0025 kPa/ C (0.00036 psi/ C, water level 0.25 mm/ C) are achieved, thus providing useful applications for the detection of the large-range liquid level in harsh environments. © 2013 Elsevier Ltd.

Cui Q.,Dalian Maritime University | Li Y.,Dalian University of Technology
Applied Energy | Year: 2014

In this paper, transportation carbon efficiency is redefined, and its inputs and outputs are obtained from a literature review. Carbon, capital and labor are selected as the inputs, and passenger turnover volume and freight turnover volume are defined as the outputs. A new model, a virtual frontier DEA (virtual frontier Data Envelopment Analysis), is applied to evaluate transportation carbon efficiencies, and cases from 15 countries during the period of 2003-2010 are analyzed to verify the results. Next, a Tobit regression model is applied to identify the important influencing factors of transportation carbon efficiency. The results indicate that compared to the technology factor and management factor, the influencing degree of a structure factor is relatively small. © 2014 Elsevier Ltd.

Xu K.,Zhejiang University | Ruan B.,Dalian University of Technology | Meng H.,Zhejiang University
Applied Thermal Engineering | Year: 2014

A theoretical expression of thermal performance factor has been derived in this paper for simple engineering evaluation of different cooling channel designs with asymmetric heating, intended for regenerative engine cooling applications in the aerospace propulsion and power-generation systems. As a specific example, numerical study has been conducted for conjugate heat transfer of the cryogenic methane in rectangular engine cooling channels at a supercritical pressure, with a constant heat flux enforced on the top channel wall. The thermal performance factor is used for practical assessment of the various engine cooling channel designs, in terms of both heat transfer enhancement and pressure loss. Results show that the geometric parameters of the cooling channel, in addition to the Nusselt number and friction factor, play a crucial role in determining the overall performance of fluid flows and heat transfer. An optimum cooling channel design could be approximated using the thermal performance factor as a first-step engineering design tool. © 2014 Elsevier Ltd. All rights reserved.

Xu H.,CAS Changchun Institute of Applied Chemistry | Liu P.-T.,Changchun University of Science and Technology | Li Y.-H.,Changchun University of Science and Technology | Han F.-S.,Dalian University of Technology
Organic Letters | Year: 2013

An unprecedented protocol for the copper-mediated direct cyanation of aryl C-H by employing 2,2′-azobisisobutyronitrile (AIBN) as a free radical "CN" source is presented. The protocol not only provides a more efficient pathway for the synthesis of aryl nitriles in terms of the yields and the loading amount of copper salts but also, more importantly, represents a novel strategy for aryl C-H cyanation via a CN free-radical mechanism as compared to the CN anion-participating protocols often reported. © 2013 American Chemical Society.

Xu S.,Zhejiang University | Zhang X.,Dalian University of Technology | Reinhardt H.W.,University of Stuttgart
ACI Structural Journal | Year: 2012

This study presents an analytical shear strength prediction equation for lightly reinforced slender concrete beams without stirrups based on the phenomenological experiment observations. The concept of the loss of bond performance between concrete and longitudinal reinforcement was used in these beams to explain the potential cause for the sudden release of longitudinal reinforcement from wrapping concrete. In the proposed equation, shear capacity was related to bond fracture resistance by introducing a new parameter: Mode II fracture toughness K IIc. The equation showed the size effect with effective depth to the power of -1/2 and was evaluated using test data published in other sources. Comparisons between the proposed formula and other prediction equations indicated that, for lightly reinforced slender concrete beams without stirrups, this developed formula can estimate the shear strength of beams with varying concrete strengths, shear span-depth ratios (a s/d), longitudinal reinforcement ratios, and beam depths with reasonable accuracy. © 2012, American Concrete Institute.

Zhou Y.-T.,Tongji University | Lee K.Y.,Dalian University of Technology
Mechanics of Materials | Year: 2014

A theoretical model of a frictional sliding contact problem for monoclinic piezoelectric materials under triangular and cylindrical punches is established. The characteristic equation related to the governing equations of monoclinic piezoelectric materials is of eight-order, which generates real and/or complex eigenvalues. Fundamental solutions that can lead to real values of physical quantities are given for both real and complex eigenvalues. By applying Fourier transform, the mixed boundary value problem is reduced to a singular integral equation of the second kind of Cauchy type. Based on exact solutions of the reduced singular integral equation, closed-form expressions of various surface stresses and electric displacement are obtained. Moreover, relations between the applied load and the contact region are obtained. Numerical results are given to show the influences of the friction coefficient on various surface stresses, electric displacement and even the width of the contact region. The underlying physics/mechanics accounting for the observations are presented. © 2013 Elsevier Ltd. All rights reserved.

Dong G.,Zhejiang Normal University | Lu Q.,Dalian University of Technology | Zhou H.,Zhejiang Normal University | Zhao X.,Zhejiang Normal University
PLoS ONE | Year: 2011

Background:This study aimed to evaluate the roles of pathological disorders in Internet addiction disorder and identify the pathological problems in IAD, as well as explore the mental status of Internet addicts prior to addiction, including the pathological traits that may trigger Internet addiction disorder.Methods and Findings:59 students were measured by Symptom CheckList-90 before and after they became addicted to the Internet. A comparison of collected data from Symptom Checklist-90 before Internet addiction and the data collected after Internet addiction illustrated the roles of pathological disorders among people with Internet addiction disorder. The obsessive-compulsive dimension was found abnormal before they became addicted to the Internet. After their addiction, significantly higher scores were observed for dimensions on depression, anxiety, hostility, interpersonal sensitivity, and psychoticism, suggesting that these were outcomes of Internet addiction disorder. Dimensions on somatisation, paranoid ideation, and phobic anxiety did not change during the study period, signifying that these dimensions are not related to Internet addiction disorder.Conclusions:We can not find a solid pathological predictor for Internet addiction disorder. Internet addiction disorder may bring some pathological problems to the addicts in some ways. © 2011 Dong et al.

Wang J.-B.,Shenyang Aerospace University | Wang M.-Z.,Dalian University of Technology
Computers and Operations Research | Year: 2013

In this paper, a three-machine permutation flow shop scheduling problem with time-dependent processing times is considered. By the time-dependent processing times we mean that the jobs processing time is an increasing function of its starting time. The objective is to find a sequence that minimizes the makespan. This problem is well known to be NP-hard. Several dominance properties and a lower bound are derived to speed up the elimination process of a branch-and-bound algorithm. Moreover, two heuristic algorithms are proposed to overcome the inefficiency of the branch-and-bound algorithm. Computational experiments on randomly generated problems are conducted to evaluate the branch-and-bound algorithm and heuristic algorithm. Computational results show that the proposed heuristic algorithm M-NEH perform effectively and efficiently. © 2012 Elsevier Ltd. All rights reserved.

Yang Y.F.,Dalian University of Technology | Han L.H.,Tsinghua University
Thin-Walled Structures | Year: 2012

This paper studies the behaviour of thin-walled concrete filled steel tube (CFST) column subjected to concentrically partial compression. A series of tests was carried out to investigate the effects of sectional type, length-to-diameter (width) ratio, partial compression area ratio and top endplate thickness on the behaviour and bearing capacity of partially loaded CFST column. Twenty-six CFST specimens were tested, and the bearing capacity, load versus deformation relation and failure mode of the specimens were obtained. It was shown that the CFST columns under concentrically partial compression generally had reasonable bearing capacity and ductility. A finite element analysis (FEA) model was developed for simulating the behaviour of CFST column subjected to concentrically partial compression, and a comparison of the performances predicted using this model showed generally good agreement with the test results. The FEA model was then used for the mechanism analysis of CFST column subjected to concentrically partial compression. Finally, a simplified model that could be used to predict the bearing capacity of the composite column under concentrically partial compression was proposed. © 2011 Elsevier Ltd. All rights reserved.

Chen C.,Drexel University | Ibekwe-SanJuan F.,University of Lyon | Hou J.,Dalian University of Technology
Journal of the American Society for Information Science and Technology | Year: 2010

A multiple-perspective cocitation analysis method is introduced for characterizing and interpreting the structure and dynamics of cocitation clusters. The method facilitates analytic and sense making tasks by integrating network visualization, spectral clustering, automatic cluster labeling, and text summarization. Cocitation networks are decomposed into cocitation clusters.The interpretation of these clusters is augmented by automatic cluster labeling and summarization.The method focuses on the interrelations between a cocitation cluster's members and their citers. The generic method is applied to a three-part analysis of the field of information science as defined by 12 journals published between 1996 and 2008: (a) a comparative author cocitation analysis (ACA), (b) a progressive ACA of a time series of cocitation networks, and (c) a progressive document cocitation analysis (DCA). Results show that the multiple-perspective method increases the interpretability and accountability of both ACA and DCA networks. © 2010 ASIS&T.

Olhoff N.,University of Aalborg | Niu B.,University of Aalborg | Cheng G.,Dalian University of Technology
International Journal of Solids and Structures | Year: 2012

The design of band-gap structures receives increasing attention for many applications in mitigation of undesirable vibration and noise emission levels. A band-gap structure usually consists of a periodic distribution of elastic materials or segments, where the propagation of waves is impeded or significantly suppressed for a range of external excitation frequencies. Maximization of the band-gap is therefore an obvious objective for optimum design. This problem is sometimes formulated by optimizing a parameterized design model which assumes multiple periodicity in the design. However, it is shown in the present paper that such an a priori assumption is not necessary since, in general, just the maximization of the gap between two consecutive natural frequencies leads to significant design periodicity. The aim of this paper is to maximize frequency gaps by shape optimization of transversely vibrating Bernoulli-Euler beams subjected to free, standing wave vibration or forced, time-harmonic wave propagation, and to study the associated creation of periodicity of the optimized beam designs. The beams are assumed to have variable cross-sectional area, given total volume and length, and to be made of a single, linearly elastic material without damping. Numerical results are presented for different combinations of classical boundary conditions, prescribed orders of the upper and lower natural frequencies of maximized natural frequency gaps, and a given minimum constraint value for the beam cross-sectional area. To study the band-gap for travelling waves, a repeated inner segment of the optimized beams is analyzed using Floquet theory and the waveguide finite element (WFE) method. Finally, the frequency response is computed for the optimized beams when these are subjected to an external time-harmonic loading with different excitation frequencies, in order to investigate the attenuation levels in prescribed frequency band-gaps. The results demonstrate that there is almost perfect correlation between the band-gap size/location of the emerging band structure and the size/location of the corresponding natural frequency gap in the finite structure. © 2012 Elsevier Ltd. All rights reserved.

Hong X.,Dalian University of Technology | Hall E.A.H.,University of Cambridge
Analyst | Year: 2012

Gold nanoparticle labelling has been shown to produce a remarkable improvement in sensitivity for small molecule detection based on Surface Plasmon Resonance (SPR) bio-sensing. The LSPR (localised SPR)-SPR coupling effect and size/mass-material properties associated with gold nanoparticles are the two main factors to change the SPR resonance condition and cause the enhancement. In this paper we examine the separation of these factors in the context of a classical SPR bio-interaction assay format, and consider the implications on the design of biodetection systems to maximise response. The coupling effect plays a distance dependent role, which allows it to be mapped. The dominant enhancement associated with this factor only occurs within ∼8 nm for a 20 nm gold nanoparticle and is changing by ∼7 nm wavelength shift/nm distance from the Au SPR thin film. Beyond this distance, the size/mass associated with the nanoparticle itself dominates the enhancement. This is demonstrated in a 20-mer DNA sequence sandwich detection, where the enhancement ratio between the coupling effect and the mass is ∼1.5:1. This simple method for deconvolution of the mass and coupling effects allows consideration of formats with LSPR nanoparticle labelling for small molecule detection and the best design of the labelling geometry. © 2012 The Royal Society of Chemistry.

Zhao J.,Dalian University of Technology
Canadian Journal of Chemistry | Year: 2011

The quasi-classical trajectory (QCT) calculations for the title reaction were carried out using the recently developed, accurate potential energy surface (PES) of the 11A′ singlet state of the OHF system The integral cross section and the product rotational alignment factor 〈P2(j′·k) 〈 were calculated as a function of collision energy. In addition, I discovered the effect of isotopic substitution on stereodynamics for the title reaction, and the influence of the rotation excitation of the reagent on stereodynamics is also presented. Both the scalar and vector properties of the reaction O(1D)+HF → OH+F(2P) are studied in this paper. It was found that the reaction is mainly controlled by an indirect reaction mechanism, and that the deep noncollinear insertion HOF well has a great impact on the dynamics of the reaction. The conclusions drawn in this paper will draw from references to similar reactions, and provide a theoretical foundation for related experiments. © 2011 Published by NRC Research Press.

Jia C.-Z.,Dalian Maritime University | Liu T.,Dalian University of Technology | Wang Z.-P.,Dalian Maritime University
Molecular BioSystems | Year: 2013

O-GlcNAcylation is a ubiquitous post-translational modification of proteins that is involved in the majority of cellular processes and is associated with many diseases. To reduce the workload and increase the relevance of experimental identification of protein O-GlcNAcylation sites, O-GlcNAcPRED, a support vector machine (SVM)-based model, was developed to capture potential O-GlcNAcylation sites. By virtue of the novel adapted normal distribution bi-profile Bayes (ANBPB) feature extraction method, O-GlcNAcPRED yielded a sensitivity of 80.83%, a specificity of 78.17% and an accuracy of 79.50% in jackknife cross-validation experiments. In an independent test on 38 recently experimentally identified human O-GlcNAcylated proteins with 67 O-GlcNAcylation sites, O-GlcNAcPRED captured 26 proteins and 39 sites, clearly outperforming the existing predictors, YinOYang and O-GlcNAcscan. © 2013 The Royal Society of Chemistry.

Zhou R.R.,Dalian University of Technology
Electronic Journal of Combinatorics | Year: 2012

We generalize Hammond-Lewis birank to multiranks for partitions into colors and give combinatorial interpretations for multipartitions such as b(n) defined by H. Zhao and Z. Zhong and Q p1,p2(n) defined by Toh congruences modulo 3, 5, 7.

Wang M.-Z.,Shenyang Aerospace University | Wang J.-B.,Dalian University of Technology
Computers and Operations Research | Year: 2012

In this paper, we consider the single-machine makespan minimization scheduling problem with nonlinear shortening processing times. By the nonlinear shortening processing times, we mean that the processing times of jobs are non-increasing nonlinear functions of their starting times. The computational complexity of the general problem remains an open problem, but we show that even with the introduction of nonlinear shortening processing times to job processing times, some special cases remain polynomially solvable. We also show that an optimal schedule of the general makespan minimization problem is V-shaped with respect to job normal processing times. A heuristic algorithm which utilize the V-shaped property is proposed, and computational experiments show that it is effective and efficient in obtaining near-optimal solutions. © 2011 Elsevier Ltd. All rights reserved.

Luo C.,Chinese Academy of Sciences | Yu B.,Dalian University of Technology
Journal of Global Optimization | Year: 2012

This paper presents a new heuristic for global optimization named low dimensional simplex evolution (LDSE). It is a hybrid evolutionary algorithm. It generates new individuals following the Nelder-Mead algorithm and the individuals survive by the rule of natural selection. However, the simplices therein are real-time constructed and low dimensional. The simplex operators are applied selectively and conditionally. Every individual is updated in a framework of try-try-test. The proposed algorithm is very easy to use. Its efficiency has been studied with an extensive testbed of 50 test problems from the reference (J Glob Optim 31:635-672, 2005). Numerical results show that LDSE outperforms an improved version of differential evolution (DE) considerably with respect to the convergence speed and reliability. © 2011 Springer Science+Business Media, LLC.

Chu S.,University of California at Riverside | Wang G.,University of California at Riverside | Zhou W.,Fudan University | Lin Y.,University of Central Florida | And 7 more authors.
Nature Nanotechnology | Year: 2011

Ultraviolet semiconductor lasers are widely used for applications in photonics, information storage, biology and medical therapeutics. Although the performance of gallium nitride ultraviolet lasers has improved significantly over the past decade, demand for lower costs, higher powers and shorter wavelengths has motivated interest in zinc oxide (ZnO), which has a wide direct bandgap and a large exciton binding energy. ZnO-based random lasing has been demonstrated with both optical and electrical pumping, but random lasers suffer from reduced output powers, unstable emission spectra and beam divergence. Here, we demonstrate electrically pumped Fabry-Perot type waveguide lasing from laser diodes that consist of Sb-doped p-type ZnO nanowires and n-type ZnO thin films. The diodes exhibit highly stable lasing at room temperature, and can be modelled with finite-difference time-domain methods. © 2011 Macmillan Publishers Limited. All rights reserved.

Lin K.,Dalian University of Technology
Journal of Network and Computer Applications | Year: 2013

For resource-constrained vehicle sensor networks (VSNs), consisting of vehicle nodes and monitor nodes, the crucial task is to track the movement of vehicles in the monitor area. In this paper, we study the problem of how to achieve the precise vehicle tracking with minimized energy consumption. We first demonstrate that the precise vehicle tracking cannot be realized when only one type sensor is equipped on monitor node. Then we employ Gaussian mixture model (GMM) to describe the distribution of the different sensory data collected by various sensors, while the mean-shift algorithm is adopted to predict the location. To obtain better performance, we further use maximum likelihood estimation to improve the monitor precision. Finally, we propose an adaptive vehicle tracking algorithm (AVT), which uses sector awakened area and sigmoid function to reduce the number of participated monitor nodes for the sake of reducing the energy. Extensive experiments are carried out to evaluate AVT with several performance criteria. Our experiment results show that the proposed AVT algorithm can effectively track mobile vehicle and perform high efficiency in conserving energy. © 2012 Elsevier Ltd.

Wang B.,Lanzhou University | Wang B.,Dalian University of Technology | Tu Y.Q.,Lanzhou University
Accounts of Chemical Research | Year: 2011

Quaternary carbon stereocenters are found in a broad range of organic compounds, including important bioactive natural products and medicinal agents. Given their ubiquity and the significant synthetic challenges they present, quaternary carbon stereocenters have long attracted great interest from synthetic organic chemists. Numerous efforts have been devoted to their construction, leading to a spectrum of strategies for creating stereogenic quaternary carbon centers. In this context, the semipinacol rearrangement has proven successful. In this extension of the pinacol rearrangement, the 1,2-carbon-to-carbon migration in a 1,2-diol has been expanded to include leaving groups other than the hydroxyl group.Over the past decade, our laboratory has explored the semipinacol rearrangement strategy for the stereoselective construction of quaternary carbon stereocenters. We have investigated various substrates, including 2,3-epoxy alcohols (also termed α-hydroxy epoxides), 2,3-aziridino alcohols, and allylic alcohols. Several promoters that effect the semipinacol rearrangement have been identified, including Lewis acids based on Al, Sm, B, Zn, and Ti for the rearrangement of α-hydroxy epoxides and 2,3-aziridino alcohols; cationic halogen species for the rearrangement of allylic alcohols; and cinchona alkaloids and chiral phosphoric acid for the asymmetric semipinacol rearrangement. Our research efforts have led to a series of valuable synthetic methods, including (1) a tandem semipinacol rearrangement and Meerwein-Ponndorf-Verley reduction, (2) a tandem semipinacol rearrangement and Tishchenko reaction, (3) a tandem semipinacol rearrangement with either an allylation or a propargylation, (4) a tandem semipinacol rearrangement and Schmidt reaction, (5) a semipinacol rearrangement of 2,3-aziridino alcohols, (6) a semipinacol rearrangement of allylic alcohols induced by halogen cation, (7) a tandem aziridination and semipinacol rearrangement of allylic alcohols, and (8) asymmetric semipinacol rearrangements with chiral organic catalysts. One hallmark of these reactions is the creation of stereogenic quaternary carbon centers with high levels of stereocontrol. In this Account, we describe the development of these synthetically useful methodologies and their successful application to the total syntheses of natural products.Our results demonstrate that the semipinacol rearrangement of carefully designed substrates constitutes an efficient approach to the stereoselective construction of quaternary carbon centers. These reactions have produced a broad array of useful compounds that lend themselves to further elaboration. Furthermore, the total synthesis of a series of alkaloids, with significant bioactivity and intriguing molecular architecture, was achieved through these semipinacol rearrangement strategies, highlighting their synthetic value. © 2011 American Chemical Society.

Nian T.,Dalian University of Technology | Han J.,University of Kansas
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2013

This paper presents an analytical solution to determine seismic active earth pressure on a rigid frictionless retaining wall of c-φ soil backfill with an infinite slope, considering horizontal and vertical seismic coefficients. This solution is a generalized explicit expression and was derived based on the Rankine earth pressure theory and the Mohr-Coulomb yield criterion. To verify the derived solution, a special case was analyzed, and its result is identical to that obtained by earlier researchers. By analyzing the distribution of the seismic active earth pressures along the wall depth, a tension crack zone behind the wall was identified, and the seismic active earth pressure coefficient considering the tension crack was obtained. This study also investigated the effects of wall friction, soil friction angle and dimensionless cohesion, backfill slope, and horizontal and vertical seismic coefficients on the seismic active earth pressure coefficients. Design charts for seismic active earth pressure coefficients were developed for the practical use of this solution. © 2013 American Society of Civil Engineers.

Meng X.,Tianjin University | Jia M.,Dalian University of Technology | Wang T.,Tianjin University
Fuel | Year: 2013

Density is an important parameter for liquid fuel to correlate the cetane number, heating value and viscosity, and directly influences the fuel injection process. Densities of biodiesel over a wide temperature range up to high temperatures are required for accurate spray and combustion modeling. In this study, densities were predicted for three methyl ester biodiesels from room temperature to 523 K at atmospheric pressure by validating against the experimental data. Three versions of the group contribution model (GCVOL) and four versions of the modified Rackett equation based methods were evaluated with special emphasis on the evaluation of the predictive ability for biodiesel densities over the high temperature range beyond 373 K. The Rackett-Soave method and the proposed Rackett-Revised method were used to predict temperature-dependent biodiesel densities for the first time, to the best of our knowledge. The computational results show that, the Rackett-Revised method is the most accurate method in predicting high-temperature biodiesel densities with the compressibility factor determined by the proposed linear regression method. Among the GCVOL group contribution methods, the revised version by updating the parameters of the double-bond gives more accurate biodiesel densities when no experimental data are available. Moreover, the modified Rackett equation based methods can present the correct temperature dependency of biodiesel densities at temperatures beyond 373 K, while the GCVOL group contribution methods fail to reproduce the fast decreasing trend. © 2013 Elsevier Ltd. All rights reserved.

Nishina N.,University of Shizuoka | Yamamoto Y.,Dalian University of Technology | Yamamoto Y.,Tohoku University
Topics in Organometallic Chemistry | Year: 2013

This chapter describes late transition metal complexes-catalyzed hydroamination, the formal addition of an H-N bond across a C-C multiple bond. Late transition metal catalysis has been intensely developed in the hydroamination and additions of various kinds of amines to C-C multiple bonds have been achieved. The reaction pathways strongly depend on the choice of metal complexes, substrates, and reaction conditions. This chapter is organized primarily based on the difference in the mechanisms of hydroamination reactions, and in the scope section concise summary of the hydroamination reaction is shown. © 2013 Springer-Verlag Berlin Heidelberg.

The measurement and control strategy of a piezo-based platform by using strain gauge sensors (SGS) and a robust composite controller is investigated in this paper. First, the experimental setup is constructed by using a piezo-based platform, SGS sensors, an AD5435 platform and two voltage amplifiers. Then, the measurement strategy to measure the tip/tilt angles accurately in the order of sub-μrad is presented. A comprehensive composite control strategy design to enhance the tracking accuracy with a novel driving principle is also proposed. Finally, an experiment is presented to validate the measurement and control strategy. The experimental results demonstrate that the proposed measurement and control strategy provides accurate angle motion with a root mean square (RMS) error of 0.21 μrad, which is approximately equal to the noise level.

Liu Y.,Ocean University of China | Li Y.-C.,Dalian University of Technology
Ocean Engineering | Year: 2011

This study examines the hydrodynamic performance of a wave absorbing double curtain-wall breakwater. The breakwater consists of a seaward perforated wall and a shoreward impermeable wall. Both walls extend from above the seawater to some distance above the seabed. Then the below gap allows the seawater exchange, the sediment transport and the fish passage. By means of the eigenfunction expansion method and a least square approach, a linear analytical solution is developed for the interaction of water waves with the breakwater. Then the reflection coefficient, the transmission coefficient and the wave forces acting on the walls are calculated. The numerical results obtained for limiting cases agree very well with previous predictions for a single partially immersed impermeable wall, the double partially immersed impermeable walls and the bottom-standing Jarlan-type breakwater. The predicted reflection coefficients for the present breakwater also agree reasonable with previous experimental results. Numerical results show that with appropriate structure parameters, the reflection and transmission coefficients of the breakwater may be both below 0.5 at a wide range of the relative water depth. At the same time, the magnitude of wave force acting on each wall is small. This is significant for practical engineering. © 2011 Elsevier Ltd. All rights reserved.

Liu H.,Dalian University of Technology
Sensors (Basel, Switzerland) | Year: 2013

Sensor drift is currently the most challenging problem in gas sensing. We propose a novel ensemble method with dynamic weights based on fitting (DWF) to solve the gas discrimination problem, regardless of the gas concentration, with high accuracy over extended periods of time. The DWF method uses a dynamic weighted combination of support vector machine (SVM) classifiers trained by the datasets that are collected at different time periods. In the testing of future datasets, the classifier weights are predicted by fitting functions, which are obtained by the proper fitting of the optimal weights during training. We compare the performance of the DWF method with that of competing methods in an experiment based on a public dataset that was compiled over a period of three years. The experimental results demonstrate that the DWF method outperforms the other methods considered. Furthermore, the DWF method can be further optimized by applying a fitting function that more closely matches the variation of the optimal weight over time.

Tian H.,KTH Royal Institute of Technology | Sun L.,KTH Royal Institute of Technology | Sun L.,Dalian University of Technology
Journal of Materials Chemistry | Year: 2011

Redox couples, as one of the crucial components of dye-sensitized solar cells, have been investigated for many years. Due to the many drawbacks of I-/I3 - electrolyte, scientists have paid more attention to seeking other alternative electrolyte systems. Up to now, the best efficiency of iodine-free redox couple-based DSCs, 7.5%, has been achieved by ferrocene/ferrocenium redox couple under AM 1.5G, 100 mW cm-2 light illumination and other redox couples also show the promising future in DSCs. In this feature article, we systematically present three series of iodine-free redox couples including metal-complexes, inorganic and pure organic redox couples, and further compare the different photovoltaic and photophysical properties of these redox couples. As a consequence, the goals of this article are to show the important progress achieved in the redox couples research area of DSCs and analyze the advantages as well as the disadvantages of these redox couples to speed up the further development of iodine-free redox couples in the future. © 2011 The Royal Society of Chemistry.

Zhu B.-X.,Dalian University of Technology
Match | Year: 2011

Assume that μ 1, μ 2, . . . , μ n are the eigenvalues of the Laplacian matrix of a graph G. The Laplacian Estrada index of G, is defined as LEE(G) = Σ n i=1 e μi. In this note, we give upper bounds for LEE(G) in terms of connectivity or matching number and characterize the corresponding extremal graphs.

Jiang W.,Dalian University of Technology | Yahiaoui K.,University of Wolverhampton
International Journal of Pressure Vessels and Piping | Year: 2012

This paper presents a validated three-dimensional thermomechanical model to investigate the effect of the welding sequence on weld induced residual stress distributions in a multipass welded piping branch junction. Three possible symmetrical welding sequences, i.e. one-welder, two-welder and four-welder sequence, which were expected to generate the least adverse stress distributions in actual welding circumstances, were proposed and evaluated. It is shown that the variations of the predicted maximum stresses along the fusion lines are not large for the three proposed welding sequences, although at both the branch and run cross section, the four-welder model predicts the highest peak residual stresses while the one-welder model gives the lowest values. As would be expected, the stress distributions predicted by the four-welder and two-welder models show more symmetrical features than those by the one-welder model. High residual stress is formed in the vicinity of the weld region irrespective of the sequence of the welding. © 2012 Elsevier Ltd.

Wang J.-B.,Shenyang Aerospace University | Wang M.-Z.,Dalian University of Technology
Mathematical and Computer Modelling | Year: 2011

In this paper, we show that the main results in a recent paper by Zhang and Yan [X. Zhang and G. Yan, Machine scheduling problems with a general learning effect, Mathematical and Computer Modelling 51 (2010) 84-90] are incorrect as an important reason is missing, that is, the processing time of a job is variable according to a general learning effect. Here we point out these wrong results by a counter-example. In addition, we give a revised model with a general learning effect. We show that some single machine scheduling problems are still polynomially solvable under the revised model. We also show that some special cases of the flowshop scheduling problems can be solved in polynomial time under the revised model. © 2010 Elsevier Ltd.

Chib A.,Nanyang Technological University | Jiang Q.,Dalian University of Technology
Journal of Computer-Mediated Communication | Year: 2014

Revisiting the medical and social models of disability, this study adopted the integrated biopsychosocial approach to examine experiences of 25 mobility-impaired respondents in Singapore with using mobile phones. We found that mobile phones provided respondents a greater degree of mobility, a sense of control, and opportunities to escape the stigma of disability, thus challenging the boundaries between the able-bodied and the disabled. Mobile phone appropriation allowed the management of personal identities and social networks, leading to a sense of empowerment. However, mobile phone usage might act as a double-edged sword for disabled people, creating mobile dependencies and a spatial narrowing of social connections. Theoretical and practical implications are discussed. © 2014 International Communication Association.

Liu Y.,Dalian University of Technology
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2015

In this paper, we consider the Cauchy problem of three-dimensional isentropic compressible magnetohydrodynamic equations with general initial data which could be either vacuum or non-vacuum under the assumption that the viscosity coefficient μ is large enough. © 2015, Springer Basel.

Tong L.,KTH Royal Institute of Technology | Gothelid M.,KTH Royal Institute of Technology | Sun L.,KTH Royal Institute of Technology | Sun L.,Dalian University of Technology
Chemical Communications | Year: 2012

A molecular Ru(ii) water oxidation catalyst was immobilized on a conductive carbon surface through a covalent bond, and its activity was maintained at the same time. The method can be applied to other materials and may inspire development of artificial photosynthesis devices. This journal is © The Royal Society of Chemistry 2012.

Gao C.,Zhejiang University | Jian L.,China University of Petroleum - East China | Jian L.,Dalian University of Technology | Luo S.,Jiangxi University of Finance and Economics
IEEE Transactions on Industrial Electronics | Year: 2012

For the economic operation of a blast furnace, the thermal state change of a blast furnace hearth (BFH), often represented by the change of the silicon content in hot metal, needs to be strictly monitored and controlled. For these purposes, this paper has taken the tendency prediction of the thermal state of BFH as a binary classification problem and constructed a ν-support vector machines (SVMs) model and a probabilistic output model based on ν-SVMs for predicting its tendency change. A highly efficient ordinal-validation algorithm is proposed to combine with the F-score method to single out inputs from all collected blast furnace variables, which are then fed into the constructed models to perform the predictive task. The final predictive results indicate that these two models both can serve as competitive tools for the current predictive task. In particular, for the probabilistic output model, it can give not only the direct result whether the next thermal state will get hot or cool down but also the confidence level for this result. All these results can act as a guide to aid the blast furnace operators for judging the thermal state change of BFH in time and further provide an indication for them to determine the direction of controlling blast furnaces in advance. Of course, it is necessary to develop a graphical user interface in order to online help the plant operators. © 2011 IEEE.

Xu Z.,University of Cambridge | Xu Z.,Dalian University of Technology | Yoon J.,Ewha Womans University | Spring D.R.,University of Cambridge
Chemical Communications | Year: 2010

A fluorescent probe was designed and shown to detect Cu2+ ratiometrically and selectively in aqueous solutions based on naphthalimide excimer-monomer switching. © 2010 The Royal Society of Chemistry.

Zhu Z.,Dongbei University of Finance and Economics | Zhu Z.,Dalian University of Technology
Physica A: Statistical Mechanics and its Applications | Year: 2013

The target of viral marketing on the platform of popular online social networks is to rapidly propagate marketing information at lower cost and increase sales, in which a key problem is how to precisely discover the most influential users in the process of information diffusion. A novel method is proposed in this paper for helping companies to identify such users as seeds to maximize information diffusion in the viral marketing. Firstly, the user trust network oriented to viral marketing and users' combined interest degree in the network including isolated users are extensively defined. Next, we construct a model considering the time factor to simulate the process of information diffusion in viral marketing and propose a dynamic algorithm description. Finally, experiments are conducted with a real dataset extracted from the famous SNS website Epinions. The experimental results indicate that the proposed algorithm has better scalability and is less time-consuming. Compared with the classical model, the proposed algorithm achieved a better performance than does the classical method on the two aspects of network coverage rate and time-consumption in our four sub-datasets. © 2013 Elsevier B.V. All rights reserved.

Kanno Y.,University of Tokyo | Guo X.,Dalian University of Technology
International Journal for Numerical Methods in Engineering | Year: 2010

This paper presents a mixed integer programming (MIP) formulation for robust topology optimization of trusses subjected to the stress constraints under the uncertain load. A design-dependent uncertainty model of the external load is proposed for dealing with the variation of truss topology in the course of optimization. For a truss with the discrete member cross-sectional areas, it is shown that the robust topology optimization problem can be reduced to an MIP problem, which is solved globally. Numerical examples illustrate that the robust optimal topology of a truss depends on the magnitude of uncertainty. © 2010 John Wiley & Sons, Ltd.

Gao X.-W.,Dalian University of Technology
Engineering Analysis with Boundary Elements | Year: 2010

This paper presents a new robust boundary element method, based on a source point isolation technique, for solving general anisotropic potential and elastic problems with varying coefficients. Different types of fundamental solutions can be used to derive the basic integral equations for specific anisotropic problems, although fundamental solutions corresponding to isotropic problems are recommended and adopted in the paper. The use of isotropic fundamental solutions for anisotropic and/or varying material property problems results in domain integrals in the basic integral equations. The radial integration method is employed to transform the domain integrals into boundary integrals, resulting in a pure boundary element analysis algorithm that does not need any internal cells. Numerical examples for 2D and 3D potential and elastic problems are given to demonstrate the correctness and robustness of the proposed method. © 2010 Elsevier Ltd. All rights reserved.

Yu M.,Dalian University of Technology
International Journal of Advancements in Computing Technology | Year: 2012

Detecting anomalies that disrupt the symmetry in two-way communications is an important task for network defense systems. The subtlety and complexity of anomalous traffic challenge the existing detection methods, and the bottleneck is how to set thresholds to adapt to the variability in network traffic. In this paper, a nonparametric adaptive CUSUM (Cumulative Sum) method is presented to meet this challenge. It has three distinct features. (i) No assumption is made on the distribution of the observations. (ii) Its detection threshold is self-adjusted so that it can adapt itself to various traffic conditions. (iii) It can react to the end of an anomaly within a required delay time. Several practical expressions for evaluating this method on its probability of false alarms and detection delays are deduced. Experiments on source-end defense against SYN flooding attacks show the efficacy of this method in detecting low intensity anomalies.

Chen S.-Y.,Dalian University of Technology
Dalian Ligong Daxue Xuebao/Journal of Dalian University of Technology | Year: 2010

Dialecticization of mathematical thinking and mathematicization of philosophical law are forefront research propositions in the area of mathematics and philosophy. Based on the variable fuzzy set theory, the theorems of unity of opposites, mutual change of quality and quantity and negation of negation are firstly put forward. They break through long-term problems that rigorous mathematical theorems were used to express three dialectical philosophical laws of materialistic dialectics of unity of opposites, mutual change of quality and quantity and negation of negation. The theorems are applied to assessment of water resources system, which includes collaborative system of land, sea and sky, and the variable fuzzy sets' principle and model about the assessment of water resources system are proposed. Finally, the theorems are used to identify mathematical and logic errors in extenics (matter-element analysis).

Yan Z.,Chinese University of Hong Kong | Wang J.,Chinese University of Hong Kong | Wang J.,Dalian University of Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2014

This paper presents a neural network approach to robust model predictive control (MPC) for constrained discrete-time nonlinear systems with unmodeled dynamics affected by bounded uncertainties. The exact nonlinear model of underlying process is not precisely known, but a partially known nominal model is available. This partially known nonlinear model is first decomposed to an affine term plus an unknown high-order term via Jacobian linearization. The linearization residue combined with unmodeled dynamics is then modeled using an extreme learning machine via supervised learning. The minimax methodology is exploited to deal with bounded uncertainties. The minimax optimization problem is reformulated as a convex minimization problem and is iteratively solved by a two-layer recurrent neural network. The proposed neurodynamic approach to nonlinear MPC improves the computational efficiency and sheds a light for real-time implementability of MPC technology. Simulation results are provided to substantiate the effectiveness and characteristics of the proposed approach. © 2013 IEEE.

Le X.,Chinese University of Hong Kong | Wang J.,Chinese University of Hong Kong | Wang J.,Dalian University of Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2014

This paper presents a neurodynamic optimization approach to robust pole assignment for synthesizing linear control systems via state and output feedback. The problem is formulated as a pseudoconvex optimization problem with robustness measure: i.e., the spectral condition number as the objective function and linear matrix equality constraints for exact pole assignment. Two coupled recurrent neural networks are applied for solving the formulated problem in real time. In contrast to existing approaches, the exponential convergence of the proposed neurodynamics to global optimal solutions can be guaranteed even with lower model complexity in terms of the number of variables. Simulation results of the proposed neurodynamic approach for 11 benchmark problems are reported to demonstrate its superiority. © 2013 IEEE.

Yang K.,Nanjing Southeast University | Gao X.-W.,Dalian University of Technology
Engineering Analysis with Boundary Elements | Year: 2010

In this paper, a new boundary element analysis approach is presented for solving transient heat conduction problems based on the radial integration method. The normalized temperature is introduced to formulate integral equations, which makes the representation very simple and having no temperature gradients involved. The Green's function for the Laplace equation is adopted in deriving basic integral equations for time-dependent problems with varying heat conductivities and, as a result, domain integrals are involved in the derived integral equations. The radial integration method is employed to convert the domain integrals into equivalent boundary integrals. Based on the central finite difference technique, an implicit time marching solution scheme is developed for solving the time-dependent system of equations. Numerical examples are given to demonstrate the correctness of the presented approach. © 2010 Elsevier Ltd. All rights reserved.

Tang Y.-Y.,Dalian University of Technology
Neuroscience Bulletin | Year: 2011

Integrative Body-Mind Training (IBMT) originates from ancient Eastern tradition. The method stresses no effort to control thoughts, but instead a state of restful alertness that allows a high degree of awareness of the body, breathing, and external instructions. A series of studies indicates that IBMT improves attention and self-regulation through interaction between the central (brain) and the autonomic (body) nervous systems. The present review mainly summarizes the recent results of IBMT studies and proposes how it changes the state of brain and body to lead to positive outcomes. Future directions in this field are also discussed. © Shanghai Institutes for Biological Sciences, CAS and Springer-Verlag Berlin Heidelberg 2011.

Gao B.,Dalian University of Technology
Journal of environmental science and health. Part. B, Pesticides, food contaminants, and agricultural wastes | Year: 2011

In this study, an Alcaligenes sp. strain DG-5 that can effectively degrade dichlorodiphenyltrichloro-ethanes (DDTs) under aerobic conditions was isolated from DDTs-contaminated sediment. Various factors that affect the biodegradation of DDTs by DG-5 were investigated. About 88 %, 65 % and 45 % of the total DDTs were consumed within 120 h when their initial concentrations were 0.5, 5 and 15 mg L1, respectively. However, almost no degradation was observed when their concentration was increased to 30 mg L1, but the addition of nutrients significantly improved the degradation, and 66 % and 90 % of the total DDTs were degraded at 336 h in the presence of 5 g L1 peptone and yeast extract, respectively. Moreover, the addition of 20 mM formate also enhanced the ability of DG-5 to transform DDTs, and its DDT transformation capacity (T(c)) value was increased by 1.8 - 2.7 fold for the pure (p,p'-DDT or o,p'-DDT only) and mixed systems (p,p'-DDT, o,p'-DDT, p,p'-DDD and p,p'-DDE). Furthermore, it was found that competitive inhibition in the biodegradation by DDT compounds occurred in the mixed system.

Inagaki M.,Hokkaido University | Qiu J.,Dalian University of Technology | Guo Q.,Shanxi Institute of Coal CAS Chemistry
Carbon | Year: 2015

Carbon foams are reviewed by focusing on their preparation and application. Their preparation processes are discussed by classifying them into five categories: blowing and carbonization, template carbonization, compression of exfoliated graphite, assembly of graphene nanosheets and others. Through these processes, density of the foam, sizes of cells and windows, as well as physical properties, are successfully controlled. Carbon foams are expected to give certain contributions to modern technology as containers for active materials for thermal energy storage, electrodes of electrochemical devices and electric energy storage, adsorbents for large molecules, and others including microwave absorption. © 2015 Elsevier Ltd. All rights reserved.

Xu L.,Dalian University of Technology
Modern Physics Letters A | Year: 2010

In this paper, a time variable cosmological constant (CC) from renormalization group equations (RGEs) is explored, where the renormalization scales μ2 = Ḣ+ 2H2 and μ2 = -Ḣ are taken respectively. The cosmological parameters, such as dimensionless energy density, deceleration parameter and effective equation of state of CC etc., are derived. Also, the cosmic observational constraints are implemented to test the model's consistency. The results show that it is compatible with cosmic data. So, it would be a viable dark energy model. © 2010 World Scientific Publishing Company.

Wu M.,Hebei Normal University | Ma T.,Dalian University of Technology
ChemSusChem | Year: 2012

Sun sans Pt: This Minireview summarizes the development of platinum-free catalysts for use as counter electrodes in dye-sensitized solar cells. These catalysts comprise various metals, carbon materials, conductive polymers, and inorganic materials (transition metal carbides, nitrides, oxides, sulfides, and phosphides). The research work reported so far highlights the importance of a proper match between counter electrode catalyst and redox couple. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tang B.,Dalian University of Technology | Brennan M.J.,Sao Paulo State University
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2012

This article concerns the free vibration of a single-degree-of-freedom (SDOF) system with three types of nonlinear damping. One system considered is where the spring and the damper are connected to the mass so that they are orthogonal, and the vibration is in the direction of the spring. It is shown that, provided the displacement is small, this system behaves in a similar way to the conventional SDOF system with cubic damping, in which the spring and the damper are connected so they act in the same direction. For completeness, these systems are compared with a conventional SDOF system with quadratic damping. By transforming all the equations of motion of the systems so that the damping force is proportional to the product of a displacement dependent term and velocity, then all the systems can be directly compared. It is seen that the system with cubic damping is worse than that with quadratic damping for the attenuation of free vibration. © 2012 American Society of Mechanical Engineers.