Showing papers by "Beijing University of Technology published in 2011"
TL;DR: In this article, the performance of different working fluids operating in specific regions was analyzed using a thermodynamic model built in Matlab together with this articlePROP, and the optimal control principle of ORC under the transient process was discussed based on the analytical results.
591 citations
TL;DR: Wang et al. as discussed by the authors investigated correlations between the occurrence of landslides with geologic and geomorphologic conditions, and seismic parameters, and found that both LAD and LPD have strong positive correlations with slope steepness, distance from the major surface rupture and seismic intensity.
539 citations
309 citations
20 Jun 2011
TL;DR: Experimental results show that the proposed new visual saliency detection method outperforms current state-of-the-art methods on predicting human fixations.
Abstract: In this paper, a new visual saliency detection method is proposed based on the spatially weighted dissimilarity. We measured the saliency by integrating three elements as follows: the dissimilarities between image patches, which were evaluated in the reduced dimensional space, the spatial distance between image patches and the central bias. The dissimilarities were inversely weighted based on the corresponding spatial distance. A weighting mechanism, indicating a bias for human fixations to the center of the image, was employed. The principal component analysis (PCA) was the dimension reducing method used in our system. We extracted the principal components (PCs) by sampling the patches from the current image. Our method was compared with four saliency detection approaches using three image datasets. Experimental results show that our method outperforms current state-of-the-art methods on predicting human fixations.
287 citations
TL;DR: TiO(2) nanotubes can modulate bone formation events at the bone-implant interface as to reach favorable molecular response and osseointegration and the diameters of nanot tubes can be precisely controlled in order to obtain better bone formation.
279 citations
TL;DR: A universal mechanism that controls the zero thermal expansion (ZTE) behavior of the antiperovskite manganese nitrides is discovered and can be reduced by nanostructuring the material, generating a form of " giant" ZTE.
Abstract: A universal mechanism that controls the zero thermal expansion (ZTE) behavior of the antiperovskite manganese nitrides is discovered Modulating the Mn occupancy at its lattice sites leads to a drastic change in the thermal expansion behavior The Mn site occupancy can be reduced by nanostructuring the material, generating a form of "giant" ZTE
230 citations
TL;DR: To the best of the knowledge, this is the first report for passively Q-switched sub-100-ns pulse operation of a graphene-based saturable absorber in a Yb-doped fiber laser.
Abstract: We demonstrate stable 70 ns pulse generation from a Yb-doped fiber laser passively Q-switched by a graphene-based saturable absorber mirror in a short linear cavity. The maximum output power was 12 mW and the highest single pulse energy was 46 nJ. The repetition rate of the fiber laser can be widely tuned from 140 to 257 kHz along with the increase of the pump power. To the best of our knowledge, this is the first report for passively Q-switched sub-100-ns pulse operation of a graphene-based saturable absorber in a Yb-doped fiber laser.
210 citations
TL;DR: Atomic-resolution evidence was obtained for an exceedingly large recoverable strain that can be sustained in the lattice of a single-crystalline Cu NW with a diameter of ∼5.8 nm, which approaches the ideal elastic limit predicted for Cu by ab initio calculations.
Abstract: Three sets of uniaxial tensile tests have been performed in situ in transmission electron microscopy/high-resolution electron microscopy on Cu nanowires (NWs) to accurately map out the sample size dependence of elastic strain limit. Atomic-resolution evidence was obtained for an exceedingly large recoverable strain (as much as 7.2%) that can be sustained in the lattice of a single-crystalline Cu NW with a diameter of ∼5.8 nm. This ultrahigh elastic strain is consistent with the predictions from molecular dynamics simulations for nanowires and approaches the ideal elastic limit predicted for Cu by ab initio calculations.
205 citations
TL;DR: Experimental results show that the FS-RBFNN can be used to design an RBF structure which has fewer hidden neurons; the training time is also much faster and the algorithm is applied for predicting water quality in the wastewater treatment process.
200 citations
TL;DR: In this paper, a two-stage estimation procedure is proposed to estimate the link function for the single index and the parameters in the single indices, as well as the linear component of the model, and asymptotic normality is established for both parametric components.
Abstract: In this paper, we study the estimation for a partial-linear single-index model. A two-stage estimation procedure is proposed to estimate the link function for the single index and the parameters in the single index, as well as the parameters in the linear component of the model. Asymptotic normality is established for both parametric components. For the index, a constrained estimating equation leads to an asymptotically more efficient estimator than existing estimators in the sense that it is of a smaller limiting variance. The estimator of the nonparametric link function achieves optimal convergence rates, and the structural error variance is obtained. In addition, the results facilitate the construction of confidence regions and hypothesis testing for the unknown parameters. A simulation study is performed and an application to a real dataset is illustrated. The extension to multiple indices is briefly sketched.
176 citations
TL;DR: In this article, the precipitation hardening of dilute Al-Er, Al-Zr and Al −Er −Zr alloys was investigated by microhardness measurements and transmission electron microscopy.
TL;DR: In this article, the effect of geometric parameters on water flow and heat transfer characteristics in micro-channel heat sink with triangular reentrant cavities is numerically investigated, and the optimal geometric parameters are obtained in principle.
TL;DR: In this paper, the effects of chelating agents on the catalytic degradation of bisphenol A (BPA) was studied in the presence of BiFeO3 nanoparticles as a heterogeneous catalyst and H2O2 as a green oxidant.
Abstract: Effects of chelating agents on the catalytic degradation of bisphenol A (BPA) was studied in the presence of BiFeO3 nanoparticles as a heterogeneous catalyst and H2O2 as a green oxidant. The oxidizing ability of H2O2 in the presence of nano-BiFeO3 alone was not so strong to degrade BPA at neutral pH values, due to the limited catalytic ability of nano-BiFeO3. Once the surface of nano-BiFeO3 was in situ modified by adding proper organic ligands, the BPA degradation was much accelerated in the pH range of 5–9. The enhancing effect of the ligand was observed to have an order of blank < tartaric acid < formic acid < glycine < nitrilotriacetic acid < ethylenediaminetetraacetic acid (EDTA). The addition of 0.25 mmol L–1 EDTA in the H2O2–BiFeO3 system at pH 5.0 and 30 °C increased the BPA removal from 20.4% to 91.2% with reaction time of 120 min. The enhancing effect of the ligand was found to be indifferent of the possible dissolution of iron from nano-BiFeO3, but correlated well with the accelerated •OH format...
TL;DR: A series of catalysts of 3D ordered macroporous (3DOM) Ce0.8Zr 0.04/Ce0.2O2-supported gold nanoparticles with controllable sizes were successfully synthesized by the facile method of gas bubbling-assisted membrane reduction (GBMR) as discussed by the authors.
Abstract: A series of catalysts of three-dimensionally ordered macroporous (3DOM) Ce0.8Zr0.2O2-supported gold nanoparticles with controllable sizes were successfully synthesized by the facile method of gas bubbling-assisted membrane reduction (GBMR). All the catalysts possess well-defined 3DOM structures, which consist of interconnected networks of spherical voids, and the Au nanoparticles are well dispersed and supported on the inner wall of the uniform macropore. The relationship between Au particle sizes and the ability to adsorb and activate oxygen was characterized by means of O2-TPD and XPS. The results show that the active oxygen species (O−) and gold ions with oxidation state of Au+ are essential for soot oxidation reaction. 3DOM Au0.04/Ce0.8Zr0.2O2catalyst with Au particle size of 2–3 nm has the strong capability of adsorption and activation of oxygen. Thus, it exhibits super-catalytic activity for diesel soot oxidation, especially at low temperature. The reaction pathways of catalytic soot oxidation in the presence or absence of NO can be outlined as follows: at low temperature ( 250 °C), the catalytic activity is strongly related to the NO gas, because NO2 derived from NO oxidation is used as intermediate to catalyze soot oxidation.
TL;DR: In this paper, the photocatalytic performance of the as-obtained samples was evaluated for the degradation of phenol in the presence of a small amount of H 2 O 2 under visible-light irradiation.
Abstract: Bismuth vanadates with multiple morphologies and/or porous structures were prepared using the alcoho-hydrothermal strategy with bismuth nitrate and ammonium metavanadate as metal source, NaOH as pH adjustor, ethanol and ethylene glycol as solvent, and/or dodecylamine (DA), oleylamine (OL) or oleic acid (OA) as surfactant. The materials were characterized by means of the XRD, Raman, TGA/DSC, FT-IR, BET, SEM, TEM, XPS, and UV–vis techniques. The photocatalytic performance of the as-obtained samples was evaluated for the degradation of phenol in the presence of a small amount of H 2 O 2 under visible-light irradiation, and the effect of phenol concentration on the photocatalytic activity was also examined. It is found that the surfactant and pH value had a significant influence on the particle morphology and even the crystalline structure of the product. Porous olive-like monoclinic BiVO 4 samples could be prepared with DA, OL or OA as surfactant at pH = 1.5 or 3.0 and alcoho-hydrothermal temperature = 100 °C. With DA as surfactant at an alcoho-hydrothermal temperature of 100 °C, short-rod-like monoclinic BiVO 4 and porous sheet-layered spherical orthorhombic Bi 4 V 2 O 11 were obtained when the pH value of the precursor solution was raised to 7.0 and 11.0, respectively. Among the BiVO 4 samples, the porous olive-like one with a surface area of 12.7 m 2 /g exhibited the best visible-light-driven photocatalytic performance for phenol degradation. It is concluded that the excellent photocatalytic activity of the porous olive-like BiVO 4 sample was associated with its higher surface area and surface oxygen vacancy density, porous structure, lower bandgap energy, and unique morphology.
TL;DR: The flexible solution-processable fabrication of the plasmonic gold nanostructures not only enables easy realization of such a random laser but also provides mechanisms for the tuning and multicolor operation of the laser emission.
Abstract: A waveguide-plasmonic scheme is constructed by coating the matrix of randomly distributed gold nanoisland structures with a layer of dye-doped polymer, which provides strong feedback or gain channels for the emission from the dye molecules and enables successful running of a random laser. Excellent overlap of the plasmonic resonance of the gold nanoislands with the photoluminescence spectrum of the dye molecules and the strong confinement mechanism provided by the active waveguide layer are the key essentials for the narrow-band and low-threshold operation of this random laser. This kind of feedback configuration potentially enables directional output from such random lasers. The flexible solution-processable fabrication of the plasmonic gold nanostructures not only enables easy realization of such a random laser but also provides mechanisms for the tuning and multicolor operation of the laser emission.
TL;DR: In this article, cubic MnO with particle sizes of ∼200nm and ∼600nm was synthesized by decomposition of MnCO 3, which exhibited promising electrochemical properties, and could potentially be used as anode material in lithium-ion batteries.
TL;DR: The results indicate that the combination of hsa-miR-375 and hSA-mi-142-5p as a predictor of disease progression has the potential to predict recurrence risk for GC patients.
University of Washington1, Weizmann Institute of Science2, Genentech3, Florida State University4, University of Wisconsin-Madison5, Kitasato University6, Cancer Research UK7, Technische Universität München8, Seoul National University9, François Rabelais University10, Boğaziçi University11, Tel Aviv University12, University of Massachusetts Medical School13, Barcelona Supercomputing Center14, Beijing University of Technology15, Huazhong University of Science and Technology16, Hebrew University of Jerusalem17, Osaka University18, Tohoku University19, Oregon State University20, Indiana University21, Utrecht University22, University of Pittsburgh23, Johns Hopkins University24, Tokyo Institute of Technology25, University of North Carolina at Chapel Hill26, Purdue University27, University of Missouri28, University of Toronto29, University of Paris-Sud30
TL;DR: A number of designed protein-protein interfaces with very favorable computed binding energies but which do not appear to be formed in experiments are generated, suggesting that there may be important physical chemistry missing in the energy calculations.
TL;DR: In this paper, a nonlinear dynamic analysis of a cantilever functionally graded materials (FGM) rectangular plate subjected to the transversal excitation in thermal environment is presented for the first time.
Abstract: Nonlinear dynamic analysis of a cantilever functionally graded materials (FGM) rectangular plate subjected to the transversal excitation in thermal environment is presented for the first time in this paper. Material properties are assumed to be temperature dependent. The nonlinear governing equations of motion for the FGM plate are derived based on Reddy’s third-order plate theory and Hamilton’s principle. The first two vibration mode functions satisfying the boundary conditions of the cantilever FGM rectangular plates are chosen to be the admissible displacement functions. Galerkin’s method is utilized to convert the governing partial differential equations to a two-degree-of-freedom nonlinear system including quadratic and cubic nonlinear terms under combined external excitations. The present study focuses on resonance case with 1:1 internal resonance and subharmonic resonance of order 1/2. The asymptotic perturbation method is employed to obtain four nonlinear averaged equations which are then solved by using Runge–Kutta method to find the nonlinear dynamic responses of the plate. It is found that chaotic, periodic and quasi-periodic motions of the plate exist under certain conditions and the forcing excitations can change the form of motions for the FGM rectangular plate.
TL;DR: In this paper, a thin film tensile technique with in situ atomic-scale observations was developed to directly characterize the atomicscale plastic deformation mechanisms and fracture process of nanocrystalline gold thin films.
TL;DR: In this article, the authors investigated the fluid flow and heat transfer characteristics in a micro-channel heat sink with offset fan-shaped reentrant cavities in sidewall, and the results indicated that the micro channel heat sink improved heat transfer performance with an acceptable pressure drop.
TL;DR: A novel system integrating anaerobic/anoxic/oxic and biological aerated filter (BAF), which could solve the sludge retention time (SRT) conflicting problem between nitrifiers and polyphosphate accumulating organisms (PAOs) by shortening SRT for PAOs in A(2)/O and lengthening SRT in BAF, was investigated in this study.
TL;DR: In this paper, the authors provide three-dimensional numerical simulations of conjugate heat transfer in the newly proposed microchannels with different structural parameters, including the lengths and widths of the constant cross-section region and the arcuate region.
TL;DR: In this article, three-dimensional ordered macroporous (3DOM) praseodymium (Pr)-modified Ce-Zr solid solutions were successfully prepared by colloidal crystal templating method.
Abstract: Three-dimensionally ordered macroporous (3DOM) praseodymium (Pr)-modified Ce-Zr solid solutions were successfully prepared by colloidal crystal templating method. They were characterized by the techniques of SEM, XRD, UV-Raman, N2 adsorption, and H2-TPR. 3DOM samples showed higher catalytic activities for soot combustion than corresponding disordered macroporous (DM) ones, which benefits from the enhanced contact efficiency between soot and ordered macroporous structure. In addition, the effects of Ce/Zr ratio on the phase composition and catalytic performances of Ce-Zr-O and Pr-Ce-Zr-O samples for soot oxidation were investigated. The results indicate that the phase compositions of Pr-modified ceria-zirconia solid solutions are similar to those of corresponding ceria-zirconia samples, and cubic–tetragonal phases coexist in the samples with moderate zirconia content, which is favorable for soot combustion. Furthermore, the effects of thermal and hydrothermal treatments on the catalytic properties for soot oxidation of 3DOM CeO2, Ce0.7Zr0.3O2 and Ce0.6Zr0.3Pr0.1O2 were comparatively studied. Compared with 3DOM bare CeO2, 3DOM Ce-Zr-based solid solutions, especially Pr-modified Ce-Zr solid solution Ce0.6Zr0.3Pr0.1O2 exhibited the highest thermal and hydrothermal stability because it possesses the lowest mobility of lattice oxygen among the three samples.
TL;DR: In this paper, a triblock copolymer P123-assisted hydrothermal strategy with bismuth nitrate and ammonium metavanadate as metal source and various bases as pH adjustor was used for the photodegradation of methylene blue (MB) under visible-light irradiation.
TL;DR: A power-efficient frequency compensation topology, Impedance Adapting Compensation (IAC), is presented, which has a normal Miller capacitor still needed to provide an internal negative feedback loop and a serial RC impedance as a load to the intermediate stage, improving performance parameters such as stability, gain-bandwidth product and power dissipation.
Abstract: A power-efficient frequency compensation topology, Impedance Adapting Compensation (IAC), is presented in this paper. This IAC topology has, on one hand, a normal Miller capacitor, which is still needed to provide an internal negative feedback loop, and on the other hand, a serial RC impedance as a load to the intermediate stage, improving performance parameters such as stability, gain-bandwidth product and power dissipation. A three-stage IAC amplifier was implemented and fabricated in a 0.35 μm CMOS technology. Experiment results show that the implemented IAC amplifier, driving a 150 pF load capacitance, achieved a gain-bandwidth product (GBW) of 4.4 MHz while dissipating only 30 μW power with a 1.5 V supply.
Journal Article•
TL;DR: In this paper, a non-concave penalized M-estimator has been proposed for sparse, high-dimensional linear regression models, which is resistant to heavy-tailed errors or outliers in the response.
Abstract: M-estimation is a widely used technique for robust statistical inference. In this paper, we investigate the asymptotic properties of a nonconcave penalized M-estimator in sparse, high-dimensional, linear regression models. Compared with classic M-estimation, the nonconcave penalized M-estimation method can perform parameter estimation and variable selection simultaneously. The proposed method is resistant to heavy-tailed errors or outliers in the response. We show that, un- der certain appropriate conditions, the nonconcave penalized M-estimator has the so-called "Oracle Property"; it is able to select variables consistently, and the esti- mators of nonzero coefficients have the same asymptotic distribution as they would if the zero coefficients were known in advance. We obtain consistency and asymp- totic normality of the estimators when the dimension pn of the predictors satisfies the conditions pn log n/n → 0 and p 2/n → 0, respectively, where n is the sample size. Based on the idea of sure independence screening (SIS) and rank correla- tion, a robust rank SIS (RSIS) is introduced to deal with ultra-high dimensional data. Simulation studies were carried out to assess the performance of the proposed method for finite-sample cases, and a dataset was analyzed for illustration.
Abstract: The present study reports a straightforward template-free route for the synthesis of core–shell Co@CoO nanocomposites by the controlled reduction of Co3O4 nanospheres. The target Co@CoO nanoparticles consist of an unsealed hollow porous CoO shell with a metal Co core, in which the outer porous CoO shell as the active anode material can be fully in contact with the electrolyte. The void within the particles provides a remarkable buffer to tolerate volume changes of the electrode materials during the insertion and extraction of lithium. Most importantly, the inner nanosized metal Co core gives a new impetus to the reversible decomposition of Li2O due to its catalytic activity. Furthermore, the exposed metal Co portion outside the nanoshells provides a favorable electrical contact between adjacent particles and greatly improves the efficiency of the electronic connection between the active material and the current collector. The Co@CoO nanocomposite maintains an excellent reversible capacity over 800 mA h g−1 after 50 cycles with an initial coulombic efficiency of 74.2%, which is much higher than that of pure CoO (67.8%). This superior electrochemical performance is closely related to the unique composition and nanostructure of the electrode material. Notably, it is the first case of a hybrid-structured Co@CoO anode material derived from the reduction process from oxide precursors. Such a conclusion may be advantageously used to guide the design of a wide range of nanostructured metal oxides.
TL;DR: In this paper, density functional theory is applied to study the electrochemical reduction of oxygen on iron phthalocyanine (FePc), iron porphyrin ( FeP), cobalt phthaloricine (CoPc) and cobalt porphyrein (CPHY) for the four metal-macrocyclic complexes.
Abstract: In this paper, density functional theory is applied to study the electrochemical reduction of oxygen on iron phthalocyanine (FePc), iron porphyrin (FeP), cobalt phthalocyanine (CoPc), and cobalt porphyrin (CoP). According to the calculation results, for the four metal−macrocyclic complexes, O2 will not directly be cleaved without the cooperation of hydrogen. In the reduction process, on FePc or FeP, H2O2 does not form as an intermediate, and O2 is reduced to H2O, while on CoPc or CoP, O2 is just reduced to H2O2. The reason why the oxygen reduction ability of FePc or FeP is higher than that of CoPc or CoP, respectively, is that the energy level of the highest-occupied 3d orbital of the former is higher than that of the later. The high energy level of the metal 3d orbital leads to the strong ability of oxygen reduction.