Showing papers by "Dalian University of Technology published in 2011"
TL;DR: In this article, the authors categorize and review recent green supply chain management literature under nine broad organizational theories, with a special emphasis on investigation of adoption, diffusion and outcomes of GSCM practices.
1,691 citations
Proceedings Article•
12 Dec 2011TL;DR: A linearized ADM (LADM) method is proposed by linearizing the quadratic penalty term and adding a proximal term when solving the sub-problems, allowing the penalty to change adaptively according to a novel update rule.
Abstract: Many machine learning and signal processing problems can be formulated as linearly constrained convex programs, which could be efficiently solved by the alternating direction method (ADM). However, usually the subproblems in ADM are easily solvable only when the linear mappings in the constraints are identities. To address this issue, we propose a linearized ADM (LADM) method by linearizing the quadratic penalty term and adding a proximal term when solving the sub-problems. For fast convergence, we also allow the penalty to change adaptively according a novel update rule. We prove the global convergence of LADM with adaptive penalty (LADMAP). As an example, we apply LADMAP to solve low-rank representation (LRR), which is an important subspace clustering technique yet suffers from high computation cost. By combining LADMAP with a skinny SVD representation technique, we are able to reduce the complexity O(n3) of the original ADM based method to O(rn2), where r and n are the rank and size of the representation matrix, respectively, hence making LRR possible for large scale applications. Numerical experiments verify that for LRR our LADMAP based methods are much faster than state-of-the-art algorithms.
1,029 citations
TL;DR: Electrically pumped Fabry-Perot type waveguide lasing from laser diodes that consist of Sb-doped p-type ZnO nanowires and n-typeZnO thin films are demonstrated, which exhibit highly stable lasing at room temperature, and can be modelled with finite-difference time-domain methods.
Abstract: 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.
571 citations
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TL;DR: This paper presents a discriminative appearance model based on superpixels, thereby facilitating a tracker to distinguish the target and the background with mid-level cues and is shown to perform favorably against existing methods for object tracking.
Abstract: While numerous algorithms have been proposed for object tracking with demonstrated success, it remains a challenging problem for a tracker to handle large change in scale, motion, shape deformation with occlusion. One of the main reasons is the lack of effective image representation to account for appearance variation. Most trackers use high-level appearance structure or low-level cues for representing and matching target objects. In this paper, we propose a tracking method from the perspective of mid-level vision with structural information captured in superpixels. We present a discriminative appearance model based on superpixels, thereby facilitating a tracker to distinguish the target and the background with mid-level cues. The tracking task is then formulated by computing a target-background confidence map, and obtaining the best candidate by maximum a posterior estimate. Experimental results demonstrate that our tracker is able to handle heavy occlusion and recover from drifts. In conjunction with online update, the proposed algorithm is shown to perform favorably against existing methods for object tracking.
557 citations
TL;DR: In this paper, the authors focus on the reported TTA based upconversion examples, the challenges that are facing the developments of TTA up-conversion and the design rationales for the triplet sensitizers and triplet acceptors.
Abstract: Triplet–triplet annihilation (TTA) is a promising upconversion approach due to its low excitation power density (solar light is sufficient), high upconversion quantum yield, readily tunable excitation/emission wavelength and strong absorption of excitation light. This review focuses on the reported TTA based upconversion examples, the challenges that are facing the developments of TTA upconversion and the design rationales for the triplet sensitizers and triplet acceptors.
543 citations
TL;DR: Superhydrophobic conjugated microporous polymers show good selectivity, fast adsorption kinetics, excellent recyclability and absorbencies for a wide range of organic solvents and oils, which make them the promising candidates for potential applications, including liquid-liquid separation, water treatment and so on.
Abstract: Superhydrophobic conjugated microporous polymers show good selectivity, fast adsorption kinetics, excellent recyclability and absorbencies for a wide range of organic solvents and oils, which make them the promising candidates for potential applications, including liquid–liquid separation, water treatment and so on.
542 citations
TL;DR: Results demonstrate that molybdenum and tungsten carbides are potential alternatives to the expensive and scarce Pt in low-cost DSSCs.
Abstract: Carbide-based catalysts, MoC and WC embedded in ordered nanomesoporous carbon were developed for the redn. of triiodide in DSSCs. CV, EIS, Tafel polarization, and photocurrent/voltage tests confirm the excellent catalytic activity of the synthesized carbide-based composites - comparable to that of expensive Pt catalyst prepd. through pyrolysis. Com. Mo2C and WC particles also effectively catalyze the redn. of triiodide to iodide despite their large particle size. The results show that the addn. of P25 and CD (carbon dye) improves the adhesion, the catalytic activity and the cond. of Mo2C and WC electrodes. The optimum amts. of added P25 and CD added were also detd. Results demonstrate that molybdenum and tungsten carbides are potential alternatives to the expensive and scarce Pt in low-cost DSSCs.
539 citations
TL;DR: The photo-to-electric conversion efficiency of the DSC sensitized by the ethanol extract of mangosteen pericarp without purification reached 1.17%.
Abstract: Twenty natural dyes, extracted from natural materials such as flowers, leaves, fruits, traditional Chinese medicines, and beverages, were used as sensitizers to fabricate dye-sensitized solar cells (DSCs). The photoelectrochemical performance of the DSCs based on these dyes showed that the open circuit voltages (Voc) varied from 0.337 to 0.689 V, and the short circuit photocurrent densities (Jsc) ranged from 0.14 to 2.69 mA cm −2 . Specifically, a high Voc of 0.686 V was obtained from the dye extracted from mangosteen pericarp sensitizer. The photo-to-electric conversion efficiency of the DSC sensitized by the ethanol extract of mangosteen pericarp without purification reached 1.17%. Moreover, various components of the ethanol extract were extracted using different organic solvents. The photoelectrochemical performance of these extracts demonstrated that rutin was the most effectual component of the sensitizer for DSC. © 2011 Elsevier B.V. All rights reserved.
503 citations
TL;DR: A bit-level permutation and high-dimension chaotic map to encrypt color image and security analysis show that the scheme can achieve good encryption result, but also that the key space is large enough to resist against common attack.
503 citations
TL;DR: Porous carbon monoliths with defined multilength scale pore structures, a nitrogen-containing framework, and high mechanical strength were synthesized through a self-assembly of poly(benzoxazine-co-resol) and a carbonization process, showing outstanding CO(2) capture and separation capacities, high selectivity, and facile regeneration at room temperature.
Abstract: Porous carbon monoliths with defined multilength scale pore structures, a nitrogen-containing framework, and high mechanical strength were synthesized through a self-assembly of poly(benzoxazine-co-resol) and a carbonization process. Importantly, this synthesis can be easily scaled up to prepare carbon monoliths with identical pore structures. By controlling the reaction conditions, porous carbon monoliths exhibit fully interconnected macroporosity and mesoporosity with cubic Im3m symmetry and can withstand a press pressure of up to 15.6 MPa. The use of amines in the synthesis results in a nitrogen-containing framework of the carbon monolith, as evidenced by the cross-polarization magic-angle-spinning NMR characterization. With such designed structures, the carbon monoliths show outstanding CO2 capture and separation capacities, high selectivity, and facile regeneration at room temperature. At ∼1 bar, the equilibrium capacities of the monoliths are in the range of 3.3–4.9 mmol g–1 at 0 °C and of 2.6–3.3 m...
494 citations
TL;DR: In this paper, nine kinds of carbon materials were introduced into dye-sensitized solar cells (DSCs) system as counter electrodes (CEs), and compared the electrochemical catalytic activity of these carbon materials with Pt for the reduction of triiodide to iodide by measuring cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel-polarization curve.
Abstract: Nine kinds of carbon materials were introduced into dye-sensitized solar cells (DSCs) system as counter electrodes (CEs). We also compared the electrochemical catalytic activity of these carbon materials with Pt for the reduction of triiodide to iodide by measuring cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel-polarization curve. The nine kinds of carbon materials in this work included synthesized well-ordered mesoporous carbon (Com), activated carbon (Ca), carbon black (Cb), conductive carbon (Cc), carbon dye (Cd), carbon fiber (Cf), carbon nanotube (Cn), discarded toner of a printer (Cp) and fullerene (C60). All carbon materials showed electrochemical catalytic activity for triiodide reduction in the DSCs system. In particular, the synthesized Com showed excellent electrochemical catalytic activity which can be comparable to the performance of Pt. After optimizing the proportion of TiO2 added into the carbon paste and the spray time of the carbon paste, the DSCs based on these carbon CEs achieved energy conversion efficiencies of 2.8–7.5%. The results demonstrate that carbon material is a promising substitute for the expensive Pt CE for low-cost DSCs.
TL;DR: The microscopic analysis and Raman scattering reveal the direct interface between Ag nanocrystal and graphene sheet, which manipulates the electronic structures of Ag@AgCl, which could provide new insights into the fabrication of high performance plasmonic photocatalyst and facilitate their practical application in environmental issues.
Abstract: Interfacing photocatalyst with graphene sheet gives rise to an extraordinary modification to the properties of the resulting hybrids. Graphene sheet grafted Ag@AgCl composite is fabricated by photoreducing AgCl/graphene oxide (GO) hybrids prepared by deposition-precipitation method. The microscopic analysis and Raman scattering reveal the direct interface between Ag nanocrystal and graphene sheet, which manipulates the electronic structures of Ag@AgCl. UV–vis absorption spectra of Ag@AgCl/reduced GO (RGO) hybrids exhibit strong absorbance in the visible region due to the surface plasmon resonance (SPR) absorption of Ag nanocrystal. In situ assembled Ag@AgCl/RGO plasmonic photocatalyst exhibits remarkable photocatalytic activity. Compared with bare Ag@AgCl nanoparticle, a 4-fold enhancement in the photodegradation rate toward rhodamine B is observed over Ag@AgCl/RGO hybrids under visible light irradiation. The large enhancement of photocatalytic activity was attributed to the effective charge transfer from...
TL;DR: The first molecular rotor (RY3) capable of dual mode fluorescence imaging (ratiometry imaging and fluorescence lifetime imaging) of intracellular viscosity is reported, and a mechanism is proposed, based on quantum chemical calculations and (1)H NMR spectra at low-temperature.
Abstract: Intracellular viscosity strongly influences transportation of mass and signal, interactions between the biomacromolecules, and diffusion of reactive metabolites in live cells. Fluorescent molecular rotors are recently developed reagents used to determine the viscosity in solutions or biological fluid. Due to the complexity of live cells, it is important to carry out the viscosity determinations in multimode for high reliability and accuracy. The first molecular rotor (RY3) capable of dual mode fluorescence imaging (ratiometry imaging and fluorescence lifetime imaging) of intracellular viscosity is reported. RY3 is a pentamethine cyanine dye substituted at the central (meso-) position with an aldehyde group (CHO). In nonviscous media, rotation of the CHO group gives rise to internal conversion by a nonradiative process. The restraining of rotation in viscous or low-temperature media results in strong fluorescence (6-fold increase) and lengthens the fluorescence lifetime (from 200 to 1450 ps). The specially...
TL;DR: A library of organic triplet sensitizers based on a single chromophore of boron-dipyrromethene (BODIPY) is proposed, paving the way for the design and applications in photovoltaics and upconversions, etc.
Abstract: Triplet-triplet annihilation (TTA) based upconversions are attractive as a result of their readily tunable excitation/emission wavelength, low excitation power density, and high upconversion quantum yield. For TTA upconversion, triplet sensitizers and acceptors are combined to harvest the irradiation energy and to acquire emission at higher energy through triplet-triplet energy transfer (TTET) and TTA processes. Currently the triplet sensitizers are limited to the phosphorescent transition metal complexes, for which the tuning of UV-vis absorption and T(1) excited state energy level is difficult. Herein for the first time we proposed a library of organic triplet sensitizers based on a single chromophore of boron-dipyrromethene (BODIPY). The organic sensitizers show intense UV-vis absorptions at 510-629 nm (e up to 180,000 M(-1) cm(-1)). Long-lived triplet excited state (τ(T) up to 66.3 μs) is populated upon excitation of the sensitizers, proved by nanosecond time-resolved transient difference absorption spectra and DFT calculations. With perylene or 1-chloro-9,10-bis(phenylethynyl)anthracene (1CBPEA) as the triplet acceptors, significant upconversion (Φ(UC) up to 6.1%) was observed for solution samples and polymer films, and the anti-Stokes shift was up to 0.56 eV. Our results pave the way for the design of organic triplet sensitizers and their applications in photovoltaics and upconversions, etc.
TL;DR: Tungsten dioxide (WO(2)) nanorods were synthesized, which showed excellent catalytic activity for the reduction of triiodide to iodide, which can match the performance of the DSC based on a Pt CE.
TL;DR: Numerical results demonstrate that the proposed method can outperform robust rotational-invariant PCAs based on L1 norm when outliers occur and requires no assumption about the zero-mean of data for processing and can estimate data mean during optimization.
Abstract: 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.
TL;DR: The fabrication and design principles for using transparent graphene interconnects in stretchable arrays of microscale inorganic light emitting diodes (LEDs) on rubber substrates are described and several appealing properties of graphene are demonstrated, including its ability to spontaneously conform to significant surface topography.
Abstract: This paper describes the fabrication and design principles for using transparent graphene interconnects in stretchable arrays of microscale inorganic light emitting diodes (LEDs) on rubber substrates. We demonstrate several appealing properties of graphene for this purpose, including its ability to spontaneously conform to significant surface topography, in a manner that yields effective contacts even to deep, recessed device regions. Mechanics modeling reveals the fundamental aspects of this process, as well as the use of the same layers of graphene for interconnects designed to accommodate strains of 100% or more, in a completely reversible fashion. These attributes are compatible with conventional thin film processing and can yield high-performance devices in transparent layouts. Graphene interconnects possess attractive features for both existing and emerging applications of LEDs in information display, biomedical systems, and other environments.
TL;DR: A superhydrophobic magnesium (Mg) alloy surface was successfully fabricated via a facile electrochemical machining process, and subsequently covered with a fluoroalkylsilane (FAS) film, and shows hierarchal rough structures and an FAS film with a low surface energy on the Mg alloy surfaces.
Abstract: A superhydrophobic magnesium (Mg) alloy surface was successfully fabricated via a facile electrochemical machining process, and subsequently covered with a fluoroalkylsilane (FAS) film. The surface morphologies and chemical compositions were investigated using a scanning electron microscope (SEM) equipped with an energy-dispersive spectroscopy (EDS) and a Fourier-transform infrared spectrophotometer (FTIR). The results show hierarchal rough structures and an FAS film with a low surface energy on the Mg alloy surfaces, which confers good superhydrophobicity with a water contact angle of 165.2° and a water tilting angle of approximately 2°. The processing conditions, such as the processing time and removal rate per unit area at a constant removal mass per unit area, were investigated to determine their effects on the superhydrophobicity. Interestingly, when the removal mass per unit area is constant at approximately 11.10 mg/cm(2), the superhydrophobicity does not change with the removal rate per unit area. Therefore, a superhydrophobic Mg alloy surface can be rapidly fabricated based on this property. A large-area superhydrophobic Mg alloy surface was also fabricated for the first time using a small-area moving cathode. The corrosion resistance and durability of the superhydrophobic surfaces were also examined.
TL;DR: The versatility of biocathodes enables us to use not only oxygen but also contaminants as possible electron acceptors, allowing nutrient removal and bioremediation in conjunction with electricity generation and create opportunities to convert electrical current into microbially generated reduced products.
TL;DR: Numerical results show that the new algorithm is promising in terms of convergence speed, success rate, and accuracy, and the proposed RABC is also capable of keeping up with the direction changes in the problems.
TL;DR: Molybdenum sulfide and tungsten sulfide are proposed as counter electrode (CE) catalysts in a I(3)(-)/I(-) and T(2)/T(-) based dye-sensitized solar cells (DSCs) system.
Abstract: Molybdenum sulfide (MoS(2)) and tungsten sulfide (WS(2)) are proposed as counter electrode (CE) catalysts in a I(3)(-)/I(-) and T(2)/T(-) based dye-sensitized solar cells (DSCs) system. The I(3)(-)/I(-) based DSCs using MoS(2) and WS(2) CEs achieved power conversion efficiencies of 7.59% and 7.73%, respectively.
TL;DR: This work has shown that integrating inorganic semiconductors with soft, elastomeric substrates to yield systems with linear elastic mechanical responses to strains that signifi cantly exceed those associated with fracture limits of the constituent materials can provide stretching to strain levels of tens of percent.
Abstract: Recent research in advanced materials and mechanics demonstrates the possibility for integrating inorganic semiconductors with soft, elastomeric substrates to yield systems with linear elastic mechanical responses to strains that signifi cantly exceed those associated with fracture limits of the constituent materials (e.g. ∼ 1% for many inorganics). This outcome can provide stretching to strain levels of tens of percent (in extreme cases, more than 100%), for diverse, reversible modes of deformation, including bending, twisting, stretching or compressing. [ 1–7 ]
TL;DR: In this paper, the nucleation of graphene on a transition metal surface, either on a terrace or near a step edge, is systematically explored using density functional theory calculations and applying the two-dimensional (2D) crystal nucleation theory.
Abstract: The nucleation of graphene on a transition metal surface, either on a terrace or near a step edge, is systematically explored using density functional theory calculations and applying the two-dimensional (2D) crystal nucleation theory. Careful optimization of the supported carbon clusters, CN (with size N ranging from 1 to 24), on the Ni(111) surface indicates a ground state structure transformation from a one-dimensional C chain to a 2D sp2 C network at N ≈ 10−12. Furthermore, the crucial parameters controlling graphene growth on the metal surface, nucleation barrier, nucleus size, and nucleation rate on a terrace or near a step edge are calculated. In agreement with numerous experimental observations, our analysis shows that graphene nucleation near a metal step edge is superior to that on a terrace. On the basis of our analysis, we propose the use of graphene seeds to synthesize high-quality graphene in large area.
TL;DR: In this paper, a simple algorithm to evaluate the quantum discord for two-qubit $X$ states was proposed by Ali, Rau, and Alber with minimization taken over only a few cases.
Abstract: Quantum discord provides a measure for quantifying quantum correlations beyond entanglement and is very hard to compute even for two-qubit states because of the minimization over all possible measurements. Recently a simple algorithm to evaluate the quantum discord for two-qubit $X$ states was proposed by Ali, Rau, and Alber [Phys. Rev. A 81, 042105 (2010)] with minimization taken over only a few cases. Here we shall at first identify a class of $X$ states, whose quantum discord can be evaluated analytically without any minimization, for which their algorithm is valid, and also identify a family of $X$ states for which their algorithm fails. And then we demonstrate that this special family of $X$ states provides furthermore an explicit example for the inequivalence between the minimization over positive operator-valued measures and that over von Neumann measurements.
TL;DR: The analysis shows that graphene nucleation near a metal step edge is superior to that on a terrace, and the use of graphene seeds to synthesize high-quality graphene in large area is proposed.
Abstract: The nucleation of graphene on a transition metal (TM) surface, either on a terrace or near a step edge, is systematically explored using density functional theory (DFT) calculations and applying the two-dimensional (2D) crystal nucleation theory. Careful optimization of the supported carbon clusters, CN (with size N ranging from 1 to 24), on the Ni(111) surface indicates a ground state structure transformation from a one-dimensional (1D) C chain to a two-dimensional (2D) sp2 C network at N ~ 10-12. Furthermore, the crucial parameters controlling graphene growth on the metal surface, nucleation barrier, nucleus size, and the nucleation rate on a terrace or near a step edge, are calculated. In agreement with numerous experimental observations, our analysis shows that graphene nucleation near a metal step edge is superior to that on a terrace. Based on our analysis, we propose the use of seeded graphene to synthesize high-quality graphene in large area.
TL;DR: The results indicate that the proposed method is effective and the software package has a friendly interface, plenty of functions, good expansibility and is easy to operate, which can be easily applied in practical engineering.
Abstract: SUMMARY
Careful selection and placement of sensors are the critical issue in the construction and implementation of an effective structural health monitoring system. A hybrid method termed the optimal sensor placement strategy (OSPS) based on multiple optimization methods is proposed in this paper. The initial sensor placement is firstly obtained by the QR factorization. Then, using the minimization of the off-diagonal elements in the modal assurance criterion matrix as a measure of the utility of a sensor configuration, the quantity of the sensors is determined by the forward and backward sequential sensor placement algorithm together. Finally, the locations of the sensor are determined by the dual-structure coding-based generalized genetic algorithm (GGA). Taking the scientific calculation software matlab (MathWorks, Natick, MA, USA) as a platform, an OSPS toolbox, which is working as a black box, is developed based on the command-line compiling and graphical user interface-aided graphical interface design. The characteristic and operation method of the toolbox are introduced in detail, and the scheme selection of the OSP is carried out on the world's tallest TV tower (Guangzhou New TV Tower) based on the developed toolbox. The results indicate that the proposed method is effective and the software package has a friendly interface, plenty of functions, good expansibility and is easy to operate, which can be easily applied in practical engineering. Copyright © 2011 John Wiley & Sons, Ltd.
TL;DR: A modified polysulfide redox couple in an organic solvent was employed in CdS quantum dot (QD)-sensitized solar cells (QDSSCs), and an unprecedented energy conversion efficiency of up to 3.2% was obtained under AM 1.5 G illumination.
Abstract: A modified polysulfide redox couple, [(CH(3))(4)N](2)S/[(CH(3))(4)N](2)S(n), in an organic solvent (3-methoxypropionitrile) was employed in CdS quantum dot (QD)-sensitized solar cells (QDSSCs), and an unprecedented energy conversion efficiency of up to 3.2% was obtained under AM 1.5 G illumination. The QDs were linked to nanoporous TiO(2) via covalent bonds by using thioglycolic acid, and chemical bath deposition in an organic solvent was then used to prepare the QDSSCs, facilitating high wettability and superior penetration capability of the TiO(2) films. A very high fill factor of 0.89 was observed with the optimized QDSSCs.
TL;DR: In this paper, a quantitative analysis of 287 policies issued by China's central government agencies between 1980 and 2005 and of 79 policies introduced between 2006 and 2008 to implement the Medium and Long-Term Plan for the Development of Science and Technology (2006-2020) is presented.
TL;DR: In this paper, the performance of Co-doped ZnO nanofibers is compared with pure ZnOs and showed that Co-depletion can improve the performance at 360°C.
Abstract: Pure and Co-doped (0.3 wt%, 0.5 wt%, and 1 wt%) ZnO nanofibers are synthesized by an electrospinning method and followed by calcination. The as-synthesized nanofibers are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) spectroscopy. Comparing with pure ZnO nanofibers, Co-doped nanofibers exhibit improved acetone sensing properties at 360 °C. The response of 0.5 wt% Co-doped ZnO nanofibers to 100 ppm acetone is about 16, which is 3.5 times larger than that of pure nanofibers (about 4.4). The response and recovery times of 0.5 wt% Co-doped ZnO nanofibers to 100 ppm acetone are about 6 and 4 s, respectively. Moreover, Co-doped ZnO nanofibers can successfully distinguish acetone and ethanol/methanol, even in a complicated ambience. The high response and quick response/recovery are based on the one-dimensional nanostructure of ZnO nanofibers combining with the Co-doping effect. The selectivity is explained by the different optimized operating temperatures of Co-doped ZnO nanofibers to different gases.