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The soot combustion on Pd-doped La2Sn2O7 pyrochlore oxides was studied. Palladium promoter was doped into the pyrochlore system via two ways: bulk substitution (La2Sn1.9Pd0.1O7) and surface impregnation (Pd/La2Sn2O7). The catalysts were characterized by XRD, BET, SEM, HRTEM, PL, XPS and H2-TPR measurements. Pd modifications increased the concentration of surface oxygen vacancy, especially Pd/La2Sn2O7. The different morphologies of palladium promoters were revealed in the two palladium-doped catalysts. Palladium was present primarily in the form of a lattice Pd2+ in the bulk-doping sample, with trace of metal palladium deposited on the surface. As for the surface-doping sample, PdO was the predominant form, accompanied with some of highly dispersed metallic palladium. Due to the adhesion of massive surface palladium species on Pd/La2Sn2O7, a strong metal oxide interaction occurred in the interface between Pd species and La2Sn2O7. The activity evaluation results show that Pd/La2Sn2O7 possesses the highest performance, exhibiting the lowest activation energy (98.83 kJ/mol) for soot combustion. Surface Pd/PdO redox couples as well as Pd-O-Sn interface species were identified to be the active phases for the superior catalytic behavior of Pd/La2Sn2O7. A possible oxidation mechanism for the reactions has been speculated. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a joint symbol-scrambling and chaotic discrete Fourier transform (DFT) precoding scheme is proposed for orthogonal frequency-division multiplexing (OFDM) visible light communication (VLC) systems for encrypted image data. In the proposed scheme, the original image data is first divided into sub-blocks and then an inter-block scrambling operation is applied to the resulting image data. Secondly, the real and imaginary parts of the transmitted QAM symbols are encrypted using two separate chaotic sequences generated from different chaotic maps. Thirdly, the resulting encrypted QAM signals are transformed into new signals using a chaotic DFT-precoding matrix in order to further improve the security and bit error rate (BER) performance of the OFDM signals. The mathematical model of our proposed encrypted OFDM-based VLC system is established and the BER formula is derived. The obtained BER formula is confirmed by our simulation results. Our simulation results also show that both symbol scrambling and image-block scrambling have no effect on the BER of the proposed DFT-precoded OFDM-based VLC system. The proposed scheme not only improves the quality of the transmitted image but also protects the transmitted image data from eavesdroppers. Highlights • A Joint image encryption and chaotic DFT precoding was proposed in OFDM VLC to enhance the security. • The formula of BER of the proposed system is derived and its validity is verified by simulation. • The proposed scheme can both achieve reducing PAPR and improving BER performance. [ABSTRACT FROM AUTHOR]

A data clipping and normalization technique is employed to improve the performance of the overall direct detection optical orthogonal frequency division multiplexing (DCO-OFDM) system. A detailed analysis of clipping distortion introduced by digital clipping and normalization is provided. The normalization operation amplifies the clipped data signal to the maximum input amplitude of a digital-to-analog converter (DAC). Based on the analysis, a BER formula of the proposed scheme is derived over the AWGN channel and single fiber channel. Performance of an optical clipped OFDM with normalization is assessed through numerical simulations and Monte Claro simulation over the AWGN channel. Theoretical analysis and simulation results both show that the clipping and normalization scheme can greatly improve the BER of an optical OFDM. In particular, BER performance of the proposed transmission scheme was measured in a practical OFDM transmission platform. The measured experimental results show that the clipped and amplified OFDM signal exhibits superior performance in comparison with the conventional OFDM signal. The received sensitivity at a BER of 10−3 for a 4 Gsamples/s (2.6667 Gbits/s) clipped and normalized OFDM signal with clipping ratio of 4 after 100 km standard single-mode fiber (SMF) transmission was improved by 4.3 dB when compared with the conventional OFDM system. The measured results also showed that the clipped OFDM signal exhibits superior performance in comparison with the conventional OFDM signal. Therefore, a clipping and normalization at the transmitter is most effective, and a substantial performance improvement can be obtained by a simple normalization after clipping. [ABSTRACT FROM AUTHOR]

Here, a novel image‐based quantized compressive sensing (QCS) framework based on complex‐valued Vandermonde (Vander) matrix is proposed. In the proposed QCS framework, a discrete wavelet transform (DWT) serves as a sparse basis and a partial complex‐valued Vander matrix serves as a measurement matrix. The theoretical analysis based on mutual coherence metric of compressive sensing (CS) theory shows that the proposed Vander measurement matrix has the best reconstruction performance among other conventional measurement matrices. The simulation results also show that the recovery quality using the proposed measurement matrix can be greatly improved compared with the other existing real‐valued measurement matrices. In particular, the experiment results also show that under the same measurement matrix, the reconstruction performance of Smoothed l0 norm (SL0) algorithm is better than that of Orthogonal Matching Pursuit (OMP) algorithm, sparsity adaptive matching pursuit (SAMP) algorithm and approximate message passing (AMP) algorithm. In addition, a sparse measurement matrix scheme is further proposed to achieve a trade‐off between recovery performance and computational complexity. The theoretical analysis and simulation results both show the proposed image‐based QCS is efficient. [ABSTRACT FROM AUTHOR]

In this paper, a two-layer image encryption scheme for a discrete cosine transform (DCT) precoded orthogonal frequency division multiplexing (OFDM) visible light communication (VLC) system is proposed. Firstly, in the proposed scheme the transmitted image is first encrypted by a chaos scrambling sequence,which is generated from the hybrid 4-D hyper- and Arnold map in the upper-layer. After that, the encrypted image is converted into digital QAM modulation signal, which is re-encrypted by chaos scrambling sequence based on Arnold map in physical layer to further enhance the security of the transmitted image. Moreover, DCT precoding is employed to improve BER performance of the proposed system and reduce the PAPR of OFDM signal. The BER and PAPR performances of the proposed system are evaluated by simulation experiments. The experiment results show that the proposed two-layer chaos scrambling schemes achieve image secure transmission for image-based OFDM VLC. Furthermore, DCT precoding can reduce the PAPR and improve the BER performance of OFDM-based VLC. [ABSTRACT FROM AUTHOR]

This paper proposes a physical layer image secure transmission scheme for discrete Fourier transform (DFT) precoded OFDM-based visible light communication systems by using Chebyshev chaos maps. In the proposed scheme, 256 subcarriers and QPSK modulation are employed. The transmitted digital signal of the image is encrypted with a Chebyshev chaos sequence. The encrypted signal is then transformed by a DFT precoding matrix to reduce the PAPR of the OFDM signal. After that, the encrypted and DFT-precoded OFDM are transmitted over a VLC channel. The simulation results show that the proposed image security transmission scheme can not only protect the DFT-precoded OFDM-based VLC from eavesdroppers but also improve BER performance. [ABSTRACT FROM AUTHOR]

Catalytic combustion is one of the most promising methods for diesel soot removal. Ln 2 Sn 2 O 7 pyrochlores substituted with different rare-earth (RE) elements (Ln = La, Nd and Sm) were prepared through co-precipitation method for catalytic combustion of soot particulates. The structural, textural and redox properties, together with the oxygen vacancy of the catalysts were investigated systematically. Their catalytic activities were evaluated by both temperature-programmed oxidation and isothermal reaction techniques. With the increasing in RE ionic radius ( r ), the Sn O bond strength in Ln 2 Sn 2 O 7 pyrochlores evaluated from the stretching IR band was decreased, resulting in the improved reducibility and enhanced oxygen vacancies of catalysts. The increase of oxygen vacancy concentration was further confirmed by photoluminescence (PL) investigations wherein upon excitation with UV radiation, the pyrochlores nanoparticles exhibited strong and sharp transition at 408 nm attributed to oxygen vacancies. Catalytic combustion and isothermal reactions revealed that the ignition activity (ignition temperature, T 5 ) and the intrinsic activity (turnover frequency, TOF) were shown to depend correlatedly on redox properties and oxygen vacancy concentrations, both of which were influenced by the substitution of different RE elements. Among the pyrochlore oxides, the as-synthesized La 2 Sn 2 O 7 sample displayed relatively the highest ignition activity and the largest intrinsic activity with TOF of 2.33 × 10 −3 s −1 . [ABSTRACT FROM AUTHOR]

This paper proposes a physical encryption scheme for discrete cosine transform (DCT) precoded OFDM-based visible light communication systems by employing chaos scrambling. In the proposed encryption scheme, the Logistic map is adopted for the chaos mapping. The chaos scrambling strategy can allocate the two scrambling sequences to the real (I) and imaginary (Q) parts of OFDM frames according to the initial condition, which enhance the confidentiality of the physical layer. The simulation experimental results prove the efficiency of the proposed encryption method for DCT precoded OFDM-based VLC systems. The experimental results show that the proposed security scheme can protect the DCT precoded OFDM-based VLC from eavesdropper, while keeping the advantage of the DCT precoding technique, which can reduce the PAPR and improve the BER performance of OFDM-based VLC. [ABSTRACT FROM AUTHOR]

The cesium-promoted LaCoO perovskite-type catalysts were synthesized for catalytic soot combustion. The cesium promoter was introduced into the perovskite system via two different ways with the same Cs loading: one is Cs doping (LaCsCoO), and the other is Cs supporting (Cs/LaCoO). The physicochemical properties of the catalysts were characterized by XRD, N-sorption, SEM, EDS, H-TPR, NO oxidation and NO sorption techniques. For Cs-supported sample, the promotion effect on the redox properties of transition metal has been observed. The catalytic NO oxidation activity on Cs-supported sample was higher than that on Cs-doped sample due to the improved reducibility. Under O atmospheres, the two kinds of Cs-containing catalysts exhibited similar ignition activities under tight conditions with soot ignition temperature decreased to about 350 °C, which can be related to the enhanced oxygen mobility and the improved contact between soot and catalysts. In the presence of NO, the superior soot oxidation activity on Cs-supported catalyst was related to its higher NO productivity, larger NO consumption and more stored nitrates accessible in soot oxidation process. Thus, the different ways to introduce cesium have different impacts on the properties and activities of the perovskite catalysts. Graphical Abstract: Cesium surface promotion is much more effective than the bulk promotion in soot oxidation over LaCoO perovskite catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • MgAlO x oxides derived from LDHs was used as support for high active NH 3 -SCR catalyst. • The highly dispersed MnO x on support were prepared by incipient wetness impregnation. • The novel catalysts exhibited superior low-temperature activity and N 2 selectivity. • The optimal catalyst MnA/MgAlO x -800 showed remarkable resistance to H 2 O. A series of novel highly dispersed MnO x on the MgAlO x support derived from layered double hydroxides (LDHs) were successfully prepared by incipient wetness impregnation method for low-temperature selective catalytic reduction of NO x with ammonia (NH 3 -SCR). The physicochemical properties and the catalytic performance of the prepared samples with different Mn precursor salt (acetate, nitrate and sulfate) and varying calcination temperatures of MgAlO x support were systematically investigated. The optimal catalyst, MgAlO x calcined at 800 °C with impregnating manganese acetate (denoted as MnA/MgAlO x -800), exhibited superior denitration performance, with NO x conversion over 80 % in the temperature range of 100–300 °C as well as remarkable resistance against H 2 O. The proper supports MgAlO x not only provided large specific area for the dispersion of the Mn, but also supplied more adsorption sites for reactant molecules. It was also found that the interaction between Mn species and MgAlO x support induced the higher concentration of Mn4+ and chemisorbed oxygen species. As suggested from in situ DRIFTs analysis, Lewis acid sites promoted the adsorption and activation of NH 3 , which facilitated the NH 3 -SCR reaction to proceed. Furthermore, E-R mechanism was proposed in the SCR reaction, evidenced by in situ DRIFTS study. [ABSTRACT FROM AUTHOR]

A scaling technique is employed to improve the performance of a Discrete Cosine Transform (DCT) precoded optical intensity-modulated direct detection (IM/DD) OFDM system, which fully exploits the dynamic range of a digital-to-analog converter (DAC). The theoretical analysis shows that the proposed scaling scheme can improve the BER performance of DCT precoded and scaled OFDM systems. The experiment results also show that the proposed scheme significantly improves the BER performance without changing the receiver structure. The measured received sensitivity at a BER of 10−3 for a 4 G samples/s (2.7 Gbits/s) DCT precoded and scaled OFDM signal and after 100 km standard single-mode fiber (SMF) transmission has been improved by 3 and 1.3 dB when compared with the original OFDM system and conventional DCT precoded OFDM system, respectively. [ABSTRACT FROM AUTHOR]

We propose and demonstrate experimentally the bit error rate (BER) performance of intensity modulation with direct detection (IM/DD) optical orthogonal frequency division multiplexing (OFDM) system by combining discrete Fourier transform (DFT) precoding with clipping. The experimental results show that the received sensitivity at a BER of 10 −4 for a 12 Gs/s DFT-precoded and clipped OFDM signal and after 100-km standard single-mode fiber transmission has been improved by 3.5 dB when compared with the original OFDM systems in the SMF link, and by 2.5 dB when compared with compared with the DFT-precoded OFDM signals. When compared with the DFT-precoded QPSK OFDM signal, the DFT-precoded and clipped OFDM QPSK signal can achieve approximately 4.5 dB of peak-to-average power ratio (PAPR) reduction at a complementary cumulative distribution functional value of 10 −3 . [ABSTRACT FROM AUTHOR]

Highlights: [•] The addition of La in Cu-based oxides increased the types of active oxygen. [•] NO x adsorption, soot oxidation and simultaneous NO x -soot removal were enhanced. [•] The possible catalytic mechanism was studied via in situ FTIR analysis. [•] Soot oxidation was promoted by the NO2 intermediate. [ABSTRACT FROM AUTHOR]

Abstract: A series of CuMgAl hydrotalcites derived oxides were prepared by co-precipitation and calcination methods and tested for the simultaneous catalytic removal of NOx and soot. The obtained samples were characterized by XRD, N2 adsorption-desorption, H2-TPR and ICP-AES techniques. The crystal phases, porous structures and redox properties of the catalysts were strongly influenced by Cu substitution contents and calcination temperatures. The CuMgAl mixed oxides with mesoporous properties exhibit high activity for the simultaneous NOx-soot removal. Among the tested catalysts, 3.0Cu-800 sample shows the best performance with the ignition temperature of soot=260°C and the total amounts of N2 =6.0×10−5 mol. Based on the experimental work, a primitive kinetics analysis was carried out from the non-steady (dynamic) TPR measurements. Linear Arrhenius plots of rates of CO2, N2 and N2O formation were observed around the onset of formation curves where the substantial amount of the soot still remains in the soot/catalyst mixture and the effective area of the soot/catalyst contact can be regarded as constant. Finally, a compensation effect was found for the formation of CO2, N2 and N2O over CuMgAl mixed oxides with CuO as the predominant phase. [Copyright &y& Elsevier]

Abstract: Rare earth hydroxide and oxide nanorods (nanobundles) have been synthesized without the addition of any templates/surfactants by a simple precipitation method under ambient temperature and pressure. The products are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), thermogravimetry (TG) and N2 adsorption/desorption. It is demonstrated that the rare earth hydroxide nanorods (nanobundles) have the diameter of 10–150nm and the length of 30–600nm. The corresponding oxides can be obtained by calcination, which preserved the nanorod (nanobundle) morphologies though a small shrinkage in sizes is observed. The influences of the aging time and precipitation agent on the formation of nanorods (nanobundles) are investigated. Accordingly the crystallization mechanism is proposed. The nucleation and growth of the hydroxide nanorods may occur in the precipitation process at relatively low (room) temperature and normal pressure without a long-time and high-temperature (pressure) hydrothermal treatment. The photoluminescence (PL) analysis is used to investigate the optical properties of the Eu2O3 nanobundles and a broadened luminescent spectrum is observed. The precipitation method is simple, highly reproducible, inexpensive, and widely applicable for the large-scale industrial production. [Copyright &y& Elsevier]

Abstract: Co–Al mixed oxides (CAO) was prepared by co-precipitation method from hydrotalcites (HT) as precursors, and their catalytic activity was investigated for the simultaneously catalytic removal of NO x and diesel soot particulates by the temperature-programmed reaction (TPR) technique. All HT samples present well crystallized, layered structures, no excess phases were detected. A nonstoichiometric spinel phase was formed by calcining the CAO at 500°C and 800°C, irrespective of the Co/Al ratio. Both the activity of soot oxidation and the selectivity to N2 formation of CAO catalysts calcined at 800°C were higher than that at 500°C. The observed difference in the catalytic performance was related to the redox properties of the catalysts and the crystallite size of HT precursors. The active species might come from Co3O4, which acted for redox-type mechanism for soot oxidation in the NO x -soot reaction. [Copyright &y& Elsevier]

MAlO (where M = Ni2+, Co2+ and Cu2+) mixed oxides derived from hydrotalcites and potassium-promoted MAlO catalysts (designated as K/MAlO; K: 5 wt.%) have been studied for diesel soot oxidation. The catalysts were characterized by XRD, N2 adsorption, TPR, FT-IR and TPO techniques. The hydrotalcites calcined at 800 °C have large surface areas in the range 17–88 m2/g and uniform mesoporous features, which resulted in high activity for diesel soot oxidation under the conditions of tight contact between soot and catalyst powders. Potassium increased the activity due to the improvement of surface mobility. The presence of NO x considerably enhanced the catalytic soot oxidation rate. The enhancement was attributed to the acceleration of soot oxidation due to NO2 as a strong oxidizing agent and intermediates of nitrate and/or nitrite species formed on the catalyst surface. [ABSTRACT FROM AUTHOR]

• Secure Compressive Sensing Based on Combined Chaotic DWT Sparse Basis and Chaotic DCT Measurement Matrix is presented. • The proposed scheme can achieve simultaneous compressive sensing and encryption with enlarging key space. • The reconstructed quality of the proposed scheme is improved when compared to the other measurement matrix schemes. In this paper, secure compressive sensing based on a combination of the chaotic discrete wavelet transform (DWT) basis and chaotic discrete cosine transform (DCT) measurement matrix is proposed. In the proposed scheme, a logistic map is employed to generate two chaotic sequences that are used to scramble the rows of the conventional DCT and original DWT matrix to form a chaotic measurement matrix and sparse basis matrix, respectively. The original image is first transformed into a sparse domain signal by the obtained chaotic DWT matrix. Thereafter, the resulting signal is compressively sampled by the obtained chaotic DCT measurement matrix. Numerical experiments show that the proposed scheme not only achieves image encryption and compression simultaneously but also enlarges the key space and improves the quality of the reconstructed image compared to that of the conventional chaotic measurement matrix method. [ABSTRACT FROM AUTHOR]

When using untrusted third parties to compress and transmit images in real‐life scenarios, it is vital to encrypt them before compression. In order to better address the issues of low security in the original image and poor reconstruction quality of the encrypted image during compressed sensing, this paper proposes a 2D compressed sensing scheme for encrypted images based on complex‐valued measurement matrix (2DCS‐CVM). Firstly, the SHA‐256 algorithm generates keys for the hyperchaotic Lorenz system, and then the chaotic sequences are used to create encrypted images with increased security through subtractive diffusion and global permutation. Secondly, the complex‐valued Vandermonde measurement matrix is utilized for 2D compressed sensing on the encrypted image, and the two‐dimensional projected gradient with embedding decryption algorithm is used to generate recovered images with improved reconstruction performance. Finally, the measurement matrix's computational complexity and transmission bandwidth are reduced through structural sparsification with sparse random matrices. Simulation results demonstrate that this scheme offers an optimal balance between storage, computational complexity, hardware implementation, and reconstruction performance while providing excellent security and robustness. [ABSTRACT FROM AUTHOR]

Constructing heterojunction is an efficient strategy to boost the charge carrier separation rate and promote the catalytic performance for photocatalysts. In this paper, amorphous CoMoS 4 was first deposited on the surface of the flower-like microspheres of CdIn 2 S 4 to fabricate CoMoS 4 /CdIn 2 S 4 composites for accelerating the photocatalytic hydrogen evolution (PHE) rate under simulated sunlight irradiation. The compositions, morphologies, and photoelectrochemical properties of the obtained samples were examined. SEM images show that a great number of CoMoS 4 nanoparticles were filled into the gaps of CdIn 2 S 4 microspheres. Optical characterization shows that the combination of CoMoS 4 and CdIn 2 S 4 strongly strengthened their light absorption capability. The remarkably promoted PHE rate of the optimum 5%-CCIS catalyst (2196 μmol g−1 h−1) was 8.4 folds larger than that for CdIn 2 S 4. More importantly, the heterostructured 5%-CCIS composite also exhibited good activity stability in the three-cycled experiments. Photoelectrochemical measurements provided the energy band potentials and demonstrated the efficient charge separation efficiency, consistent with the photocatalytic activity of CoMoS 4 /CdIn 2 S 4 composites for hydrogen production. This study will provide a new strategy to fabricate CoMoS 4 -based heterostructures for boosting the hydrogen evolution under visible light. The charge separation efficiency and hydrogen production activity of CoMoS 4 /CdIn 2 S 4 composites were greatly improved compared with pure CdIn 2 S 4. [Display omitted] • The amorphous CoMoS 4 is successfully deposited on the flower-like CdIn 2 S 4 microspheres. • The photocatalytic hydrogen evolution rate of CoMoS 4 /CdIn 2 S 4 is greatly improved. • The hydrogen evolution rate over 5%-CCIS is 8.4 times higher than that of CdIn 2 S 4. • The strong light absorption and efficient charge separation result in the excellent activity. [ABSTRACT FROM AUTHOR]

A novel active Ca-Co dually-doping pyrochlore oxide La2−xCaxSn2−yCoyO7 catalyst was synthesized by the sol-gel method for catalytic oxidation of soot particulates. The microstructure, atomic valence, reduction, and adsorption performance were investigated by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), H2-TPR (temperature-programmed reduction), and in situ diffuse reflection infrared Fourier transformed (DRIFTS) techniques. Temperature programmed oxidation (TPO) tests were performed with the mixture of soot-catalyst under tight contact conditions to evaluate the catalytic activity for soot combustion. Synergetic effect between Ca and Co improved the structure and redox properties of the solids, increased the surface oxygen vacancies, and provided a suitable electropositivity for oxide, directly resulting in the decreased ignition temperature for catalyzed soot oxidation as low as 317 °C. The presence of NO in O2 further promoted soot oxidation over the catalysts with the ignition temperature decreased to about 300 °C. The DRIFTS results reveal that decomposition of less stable surface nitrites may account for NO2 formation in the ignition period of soot combustion, which thus participate in the auxiliary combustion process. [ABSTRACT FROM AUTHOR]

A series of promising Ce–Co–Fe catalysts were successfully synthesized using a cetyl-trimethylammonium-bromide-assisted co-precipitation method and investigated for diesel soot combustion. The surface morphological and structural properties were systematically examined using various techniques: X-ray diffraction, scanning electron microscope, N2 adsorption–desorption, Raman spectroscopy, temperature-programmed reduction and in situ diffuse reflection infrared Fourier transform spectroscopy. The catalyst–soot combustion activities were tested in O2 and NO + O2 using a temperature-programmed technique. Nanometer crystalline solid solutions were formed with high surface areas when the Fe and Co cations were co-doped in the ceria lattice. Transition metals doping played a key role in increasing oxygen vacancies and promoting the redox performance of Ce–Co–Fe catalysts. Co–Fe co-doping accelerated the oxidation of soot under both "tight" and "loose" contact conditions. Among all the ceria-based catalysts, Ce80Co15Fe5 showed superior activity with T10 = 256 °C and high selectivity with S CO 2 = 100 % under tight a contact mode. The observed high catalytic activity following co-doping was proved to have occurred because of various reasons such as improved redox properties, increased oxygen vacancies and high surface area. The presence of NO in O2 also promoted soot oxidation, which follows the NO2-assisted mechanism. Moreover, the in situ DRIFTS performed under an isothermal condition in NO + O2 confirmed the strong adsorption capacity for NOx species on the doped ceria catalyst. [ABSTRACT FROM AUTHOR]

• Hand dexterity is significantly related to motor imagery-induced neural activities. • Purdue Pegboard Test could best predict the motor imagery-induced rERD. • The MIQ-3 assessment questionnaire could predict the kinesthetic imagery ability. • α band rERD has obvious correlations with psychological and behavioral scores. Motor imagery based brain-computer interfaces (MI-BCIs) have excellent application prospects in motor enhancement and rehabilitation. However, MI-induced electroencephalogram features applied to MI-BCI usually vary from person to person. This study aimed to investigate whether the motor ability of the individual upper limbs was associated with these features, which helps understand the causes of inter-subject variability. We focused on the behavioral and psychological factors reflecting motor abilities. We first obtained the behavioral scale scores from Edinburgh Handedness Questionnaire, Maximum Grip Strength Test, and Purdue Pegboard Test assessments to evaluate the motor execution ability. We also required the subjects to complete the psychological Movement Imagery Questionnaire-3 estimate, representing MI ability. Then we recorded EEG signals from all twenty-two subjects during MI tasks. Pearson correlation coefficient and stepwise regression were used to analyze the relationships between MI-induced relative event-related desynchronization (rERD) patterns and motor abilities. Both Purdue Pegboard Test and Movement Imagery Questionnaire-3 scores had significant correlations with MI-induced neural oscillation patterns. Notably, the Purdue Pegboard Test of the left hand had the most significant correlation with the alpha rERD. The results of stepwise multiple regression analysis showed that the Purdue Pegboard Test and Movement Imagery Questionnaire-3 could best predict the MI-induced rERD. The results demonstrate that hand dexterity and fine motor coordination are significantly related to MI-induced neural activities. In addition, the method of imagining is also relevant to MI features. Therefore, this study is meaningful for understanding individual differences and the design of user-centered MI-BCI. [ABSTRACT FROM AUTHOR]

The superior catalytic activity and N 2 selectivity contributes to the synergy between oxidative Pt and oxygen vacancy. [Display omitted] • The amount of oxygen vacancy and oxidative Pt species changes with Pt/Cu ratio. • Pt 1 Cu 1 -CeO 2 possesses the best low-temperature activity and good N 2 selectivity. • The increased oxygen vacancy provides adequate adsorption sites for NO molecules. • The amount of Ptδ+ in Pt 1 Cu 1 sample results in a moderate strength of CO adsorption. • The strengthened synergy of two active sites improves activity and selectivity. Both the Pt electronic state and oxygen vacancy within supports play an important role in catalytic reactions. However, it remains a challenge for simultaneous achievement of modulating Pt electronic state as well as tuning oxygen vacancy content. In this work, we have prepared a series of PtCu-CeO 2 catalysts with different Pt/Cu ratios. The electronic state of Pt is modulated by means of Pt-Cu alloy effect, while the oxygen vacancy content is tuned by the constructed PtCu-CeO 2 interfaces. When the as-prepared PtCu-CeO 2 catalysts are used for the reduction of NO x by CO, the one with Pt/Cu ratio of 1 (Pt 1 Cu 1 -CeO 2) possesses twice higher NO conversion and superior N 2 selectivity below 200℃than that of monometallic Pt-CeO 2. The characterization results illustrate that Pt 1 Cu 1 -CeO 2 catalyst exhibits a moderate strength for CO adsorption and a fast NO dissociation ability, resulting in the formation of N 2 rather than N 2 O intermediate. This work is expected to open an alternative avenue for boosting the catalytic performances by simultaneous modulation of Pt electronic state and oxygen vacancy content. [ABSTRACT FROM AUTHOR]

The measurement matrix used influences the performance of image reconstruction in compressed sensing. To enhance the performance of image reconstruction in compressed sensing, two different Gaussian random matrices were orthogonalized via Gram–Schmidt orthogonalization, respectively. Then, one was used as the real part and the other as the imaginary part to construct a complex-valued Gaussian matrix. Furthermore, we sparsified the proposed measurement matrix to reduce the storage space and computation. The experimental results show that the complex-valued Gaussian matrix after orthogonalization has better image reconstruction performance, and the peak signal-to-noise ratio and structural similarity under different compression ratios are better than the real-valued measurement matrix. Moreover, the sparse measurement matrix can effectively reduce the amount of calculation. [ABSTRACT FROM AUTHOR]

In north-west Jiangxi, China, most shale-gas exploration has been focused on the Lower Cambrian Hetang and Guanyintang formations, whereas the Upper Ordovician Xinkailing formation shale has been ignored for years due to heavy weathering. This study systematically analyzed gas source conditions, reservoir conditions and gas-bearing ability in order to reveal the shale-gas accumulation conditions of the Xinkailing formation. The results show that the Xinkailing formation is characterized by thick deposition of black shale (10–80 m), high organic content (with total organic carbon between 1.18% and 3.11%, on average greater than 2%), relatively moderate thermal evolution (with vitrinite reflectance between 2.83% and 3.21%), high brittle-mineral content (greater than 40%), abundant nanopores and micro-fractures, very good adsorption ability (adsorption content between 2.12m3/t and 3.47m3/t, on average about 2.50m3/t), and strong sealing ability in the underlying and overlying layers, all of which favor the generation and accumulation of shale gas. TheWuning-Lixi and Jinkou-Zhelin areas of the Xinkailing formation were selected as the most realistic and favorable targets for shale-gas exploration and exploitation. In conclusion, the Wuning area has great potential and can provide a breakthrough in shale gas with further investigation. [ABSTRACT FROM AUTHOR]

In this paper, a complex-valued Zadoff–Chu measurement matrix is proposed and used in an image-based quantized compressive sensing (CS) scheme. The results of theoretical analysis and simulations show that the reconstruction performance generated by the proposed Zadoff–Chu measurement matrix is better than that obtained by commonly used real-valued measurement matrices. We also applied block compressive sensing (BCS) to reduce the computational complexity of CS and analyzed the effect of block size on the reconstruction performance of the method. The results of simulations revealed that an appropriate choice of block size can not only reduce the computational complexity but also improve the accuracy of reconstruction. Moreover, we studied the effect of quantization on the reconstruction performance of image-based BCS through simulations, and the results showed that analog-to-digital converters with medium resolutions are sufficient to implement quantization and achieve comparable reconstruction performance to that obtained at high resolutions, based on which an image-based BCS framework with low power consumption can thus be developed. [ABSTRACT FROM AUTHOR]

[Display omitted] The classical strong metal-support interaction (SMSI) plays a key role in improving thermal stability for supported Au catalysts. However, it always decreases the catalytic activity because of the encapsulation of Au species by support. Herein, we demonstrate that Al3+ is a functional additive which could effectively improve both catalytic activity and sintering resistant property for H 2 pretreated Al3+ doped CeO 2 supported Au (AuCeAl) catalyst at high temperature. The physical characterization and in-situ DRIFTS results provide insight that more oxygen vacancies generated by Al3+ doping could be as preferential adsorption sites for CO molecules when the encapsulation of Au species occurred, which is certificated by an accelerated formation of bicarbonate species. In the meantime, smaller Au nanoparticles with higher dispersion (2.8 nm, 85.63%) is achieved in AuCeAl catalysts, compared with that in CeO 2 supported Au (AuCe) catalysts (5.1 nm, 36.17%). Additionally, the as-prepared AuCeAl catalysts also have superior catalytic performance even after calcination at 800 °C in air. [ABSTRACT FROM AUTHOR]

In the past decade, various fragile digital watermarking techniques have been proposed for monoscopic image authentication and temper detection. In this paper, a novel binocular visual characteristics based pixel-wise fragile watermarking scheme for stereoscopic image authentication and tamper detection is proposed. The scheme consists of two processes: embedding of the stereoscopic image authentication message and tamper detection. In the watermark embedding process, the binocular just noticeable difference (BJND) model is used for guiding watermark embedding, which is convenient for achieving a balanced relationship between watermarking capacity and visual transparency. In the tamper detection process, a probability theory and an algorithm of binocular disparity are employed to improve previously obtained detection results and to enhance authentication accuracy. Moreover, to improve the security of the proposed scheme, MD5 hash function and chaotic map are used. Experimental results reveal that the proposed scheme is not only secure, but also achieves superior tamper detection for different attacks. [ABSTRACT FROM AUTHOR]

[Display omitted] • The high sensitivity of the probe with a detection limit of 58 nM. • Successful detection of endogenous and exogenous CO in living cells. • Capable of detecting CO in zebrafish. • NIR probe with a high signal-to-noise ratio for imaging CO in biological samples. Carbon monoxide (CO) is a highly emitted atmospheric pollutant that can pose a serious health risk when its concentration is too high. However, endogenous CO plays an important role in maintaining human health. The development of tools capable of detecting CO in environmental samples and biological samples is therefore essential. Although CO fluorescent probes have been reported, their further applications are limited by factors such as low sensitivity and emission wavelength. Here, we have constructed a CO probe with simple structure, high sensitivity, good selectivity and near-infrared (NIR) emission characteristics. The probe uses the dicyanoisophorone derivative as fluorophore and connects allyl moiety as the reaction site. After the response, the intramolecular charge transfer (ICT) process turns on and releases strong near-infrared fluorescence at 675 nm. The linear range of fluorescence intensity of the probe for CO concentration is 1–10 μM and the detection limit is as low as 58 nM. The high sensitivity and NIR emission give the probe excellent imaging of cellular exogenous and endogenous CO. Moreover, the probe can also be used to image CO in zebrafish. There is reason to believe that the probe can be a powerful tool for detecting CO concentrations in environmental samples and for analyzing the biological role of CO in organisms. [ABSTRACT FROM AUTHOR]

We propose an all-fiber broadband circular polarizer based on leaky mode coupling and a phase-matched turning point (PMTP) in a chirped, double-helix, chiral, long-period, fiber grating (CLPG). The CLPG was coated with a material in which the refractive index was higher than that of the fiber cladding, enabling the coupling of the core mode to leaky modes to achieve a desired extinction ratio. The complex coupled-mode theory was employed to investigate the coupling mechanism and conditions under which the desired coupling efficiency could be achieved. Moreover, the PMTP in phase-matched curves, which resolved the conflict between the operating bandwidth and the grating pitch range of the CLPG and made a large bandwidth with a small grating pitch possible, was used in the design to achieve a compact structure. Finally, two broadband circular polarizers with an extinction ratio above 25 dB were simulated; one had a bandwidth of over 120 nm and a length of 3.5 cm, and the other had a bandwidth of over 300 nm and a length of 8 cm. [ABSTRACT FROM AUTHOR]

Octylphenols, considered as xenoestrogens, mainly exist as 4-tert-octylphenol (OP) in aquatic environments. The high stability and accumulation of OP in aquatic systems have caused endocrine disruption. The OP in surface water in Jinan, China was analyzed by gas chromatography-mass spectrometry (GC-MS) coupled with solid phase extraction (SPE). Water samples were extracted by SPE on a cartridge system containing C-18 as sorbent. To increase sensitivity and selectivity, OP was derivatized to 4-tert-octyl-phenoxy silane. With the use of phenanthrene-d10 as internal standard, the detection limit based on signal-to-noise ratio ( S/N = 3) was 0.06 ng/mL. The average recovery was from 84.67% to 109.7%. The precision of the method given as the relative standard deviations (RSD) was within the range 6.24%–12.96%. In the target water samples, the concentrations of OP were as follows: 15.88–71.24 ng/L for Jinxiuchuan Reservoir, 3.850–26.68 ng/L for the city moat, 6.930–41.56 ng/L for Daming Lake, 66.03–474.2 ng/L for Xiaoqing River, 14.66–17.72 ng/L for the Yellow River, and 10.60–26.43 ng/L for Queshan Reservoir. The Xiaoqing River was seriously polluted due to the discharge of wastewater from Jinan. Jinxiuchuan Reservoir had a higher concentration of OP compared with the Yellow River and Queshan Reservoir, which is ascribed to the surrounding human activities. These data are reported for the first time, providing strong support for the control of OP pollution in Jinan. [ABSTRACT FROM AUTHOR]

Abstract: Potassium-promoted Mg–Al hydrotalcite mixed oxides were studied for soot combustion with O2. The significant activity was elucidated by an oxygen spillover mechanism. First, the surface-activated oxygen on K sites might spill over to the free carbon sites on soot to form a carbon–oxygen complex, ketene group, which was identified as the reaction intermediate. Then the ketene group combined with another active oxygen species to give out CO2. Two kinds of K species, Mg(Al)–O–K (tightly bound to Mg or Al) and free (isolated) K, were determined to be catalytically active sites by kinetic investigations. They could increase the reactivity and amount of surface active oxygen responsible for formation of the ketene group. The stability of K was greatly improved through the interaction with Al, which is a contribution to soot combustion of Al addition into MgO to form a K-promoted composite oxide via the hydrotalcite route. [Copyright &y& Elsevier]

The simultaneous catalytic removal of NOx and soot over the rare earth element (REE) oxide-based mixture oxides loaded with potassium and transition nanosized metal oxide (designated as M/K/REE oxide) was investigated by using temperature-programmed reaction (TPR). The influence of the type of REE oxides together with the type and amount of transitional metal oxides on the catalytic removal activity was discussed. K/Nd2O3 was found to be the most active oxide among the REE oxides to simultaneous remove the NOx and soot under lean conditions. Chromium oxide was more active than the other transition metal oxides on enhancing the activity of soot oxidation of Nd2O3 loaded with potassium. The optimum loading level of chromium was about 10 wt%, with ignition temperature at about 237°C and the conversion ratio NO → N2 about 24.1%. The Mn-loading on K/Nd2O3 resulted in the biggest conversion efficiency of NO to N2 at about 30.2%. The increasing catalytic reaction of NOx–soot activities is attributed to the formation of complex crystalline phase in the catalyst together with the improving contacting between catalysts and soot. [ABSTRACT FROM AUTHOR]

NOx storage-reduction (NSR) is a potential approach for the effective removal of NOx under the lean conditions in lean-burn engines. Herein, manganese-doped mixed oxides (Mn/MgAlOx) with high performance for low temperature NOx storage and release were derived from hydrotalcites precursors prepared by a facile coprecipitation method. The catalysts were characterized by X-ray diffraction (XRD), SEM, N2 adsorption-desorption, H2-TPR, FT-IR, and X-ray photoelectron spectroscopy (XPS) techniques. The Mn-doped MgAlOx catalysts exhibited high NOx storage capacity (NSC) at low temperature range (150–300 °C), which was related to their increased surface area, improved reducibility and higher surface Mn3+ content. The largest NSC measured, 426 μmol/g, was observed for NOx adsorption at 200 °C on Mn15 catalyst (the sample containing 15 wt% of Mn). The in situ DRIFTS spectra of NOx adsorption proved that the Mn-doped hydrotalcite catalysts are preferred for low temperature NOx storage and release due to their ability to store NOx mainly in the form of thermally labile nitrites. NSR cycling tests revealed the NOx removal rate of Mn15 sample can reach above 70% within the wide temperature range of 150–250 °C. Besides, the influence of CO2, soot, H2O and SO2 on NOx storage performance of Mn15 catalyst was also studied. In all, owning to their excellent NOx storage capacity, NSR cycling performance, and resistance to CO2, soot, SO2 and H2O, the Mn-doped MgAlOx NSR catalysts have broad application prospects in NOx control at low temperatures. [ABSTRACT FROM AUTHOR]

Two novel helical poly(phenylacetylene) derivatives containing chiral phenylethyl carbamate residues in the end of each side chain (PPA‐S and PPA‐R) were synthesized by polymerization of the corresponding phenylacetylene monomers using Rh(nbd)BPh4 as a catalyst in DMF. The enantioseparation properties of the polymers were evaluated as coated‐type chiral stationary phases (CSPs) for high‐performance liquid chromatography (HPLC). Under the same chromatographic conditions, PPA‐S and PPA‐R showed different enantioseparation properties, indicating that the different interactions between the analytes and the polymers, which result from the different chiral phenylethyl carbamate groups in the end of each side chains. Racemates 1, 7, and 8 could be better resolved on PPA‐S, while racemate 6 was separated on PPA‐R more efficiently. In addition, the coated‐type CSPs showed good solvent tolerability and could work without any damage by introducing the polar solvents, such as CHCl3 and THF, in eluent. Moreover, some racemates could be better resolved on these coated‐type CSPs with the addition of THF to the eluent. [ABSTRACT FROM AUTHOR]

Purpose: Aberrant expression of microRNAs contributes to the progression of pancreatic cancer by targeting downstream genes. A novel regulatory axis, miR-1224-5p/ELF3, was identified by bioinformatic analysis and experimental verification. Studies of the underlying molecular mechanisms behind this axis lead to a better understanding of the development of pancreatic cancer. Materials and Methods: The differential expression of miR-1224-5p and ELF3 was verified based on Gene Expression Omnibus (GEO) datasets and clinical samples. The relationship between miR-1224-5p and ELF3 was demonstrated by luciferase assay and Western blot. The related signaling pathways of the miR-1224-5p/ELF3 axis in pancreatic cancer were investigated by gene set enrichment analysis (GSEA) and verified by Western blot. An analysis between ELF3 expression and immune infiltration was performed. Cellular and animal experiments were utilized to explore the effects of miR-1224-5p and ELF3 in pancreatic cancer. Results: Suppressed expression of miR-1224-5p in pancreatic tumor tissues and cancer cells was identified first. Furthermore, miR-1224-5p is correlated with clinicopathological features, and decreased expression of miR-1224-5p indicates poor prognosis. miR-1224-5p serves as a tumor suppressor and inhibits malignant behaviors of pancreatic cancer based on in vivo and in vitro assays. The putative target gene ELF3 was predicted by bioinformatic analysis and confirmed by dual-luciferase reporter assay. Overexpression of ELF3 can improve the malignant behaviors of pancreatic cancer and demonstrates poor prognosis and advanced clinical stage. The inhibitory role of miR-1224-5p in pancreatic cancer is manifested by its direct targeting of ELF3. A negative correlation between ELF3 expression and immune cell infiltration was identified, suggesting an immunosuppressive state resulting from ELF3 overexpression. The PI3K/AKT/Notch signaling pathways and epithelial-to-mesenchymal transition (EMT) are important underlying mechanisms. Conclusion: The miR-1224-5p/ELF3 axis may serve as a new diagnostic, therapeutic, and prognostic biomarker in pancreatic cancer. The related PI3K/AKT/Notch/EMT signaling pathways greatly promote the elucidation of the progression of pancreatic cancer. [ABSTRACT FROM AUTHOR]

The adverse effects of high concentration of phenolic compounds in wastewater on aquatic organisms are a major environmental issue. In recent years, treating organic wastewater by algae has attracted attention because this treatment is economic, efficient and eco-friendly. Here we review the use of algae in removing phenol and phenolic derivatives. We discuss phenolic wastewater treatment, mechanisms of adsorption and degradation, and effects of excessive phenols on algal cells. [ABSTRACT FROM AUTHOR]

Hexavalent chromium is one of the main heavy metal pollutants. As the environmental legislation becomes increasingly strict, seeking new technology to treat wastewater containing hexavalent chromium is becoming more and more important. In this research, a novel modified ultrafiltration membrane that could be applied to adsorb and purify water containing hexavalent chromium, was prepared by polyvinylidene fluoride (PVDF) blending with 2-aminobenzothiazole via phase inversion. The membrane performance was characterized by evaluation of the instrument of membrane performance, infrared spectroscopy (FTIR), scanning electron microscope (SEM), and water contact angle measurements. The results showed that the pure water flux of the PVDF/2-aminobenzothiazole modified ultrafiltration membrane was 231.27 L/m2·h, the contact angle was 76.1°, and the adsorption capacity of chromium ion was 157.75 μg/cm2. The PVDF/2-aminobenzothiazole modified ultrafiltration membrane presented better adsorption abilities for chromium ion than that of the traditional PVDF membrane. [ABSTRACT FROM AUTHOR]

Mesoporous ceria and transition metal-doped ceria (M 0.1 Ce 0.9 O 2 (M = Mn, Fe, Co, Cu)) catalysts were synthesized via CTAB-assisted method. The physicochemical properties of the prepared catalysts were characterized by XRD, DLS analysis, SEM, BET, Raman, H 2 -TPR and in situ DRIFT techniques. The catalytic activity tests for soot oxidation were performed under tight contact of soot/catalyst mixtures in the presence of O 2 and NO + O 2 , respectively. The obtained results show that mesoporous ceria-based solid solutions can be formed with large surface areas and small crystallite size. Transition metals doping enhances the oxygen vacancies and improves redox properties of the solids, resulting in the increased NO oxidation capacity and NO x adsorption capacity. The soot oxidation activity in the presence of O 2 is enhanced by doping transition metal, which may be related to their high surface area, increased oxygen vacancies and improved redox properties. The soot combustion is accelerated by the NO 2 -assisted mechanism under NO + O 2 atmosphere, facilitating an intimate contact between the soot and the catalyst. [ABSTRACT FROM AUTHOR]

Background: Motor imagery (MI) induced EEG patterns are widely used as control signals for brain-computer interfaces (BCIs). Kinetic and kinematic factors have been proved to be able to change EEG patterns during motor execution and motor imagery. However, to our knowledge, there is still no literature reporting an effective online MI-BCI using kinetic factor regulated EEG oscillations. This study proposed a novel MI-BCI paradigm in which users can online output multiple commands by imagining clenching their right hand with different force loads.Methods: Eleven subjects participated in this study. During the experiment, they were asked to imagine clenching their right hands with two different force loads (30% maximum voluntary contraction (MVC) and 10% MVC). Multi-Common spatial patterns (Multi-CSPs) and support vector machines (SVMs) were used to build the classifier for recognizing three commands corresponding to high load MI, low load MI and relaxed status respectively. EMG were monitored to avoid voluntary muscle activities during the BCI operation. The event-related spectral perturbation (ERSP) method was used to analyse EEG variation during multiple load MI tasks.Results: All subjects were able to drive BCI systems using motor imagery of different force loads in online experiments. We achieved an average online accuracy of 70.9%, with the highest accuracy of 83.3%, which was much higher than the chance level (33%). The event-related desynchronization (ERD) phenomenon during high load tasks was significantly higher than it was during low load tasks both in terms of intensity at electrode positions C3 (p < 0.05) and spatial distribution.Conclusions: This paper demonstrated the feasibility of the proposed MI-BCI paradigm based on multi-force loads on the same limb through online studies. This paradigm could not only enlarge the command set of MI-BCI, but also provide a promising approach to rehabilitate patients with motor disabilities. [ABSTRACT FROM AUTHOR]

In the field of practical three-dimensional (3D) applications, blind measurement of the perceptual quality of distorted 3D images remains a challenging research topic. In this paper, we propose a completely blind 3D image quality measurement (IQM) metric that utilizes a binocular vision mechanism to better align with human perception. As its primary focus, this study is inspired by the visual processing in the primary visual cortex (V1) and the higher visual areas (V2) of binocular vision to facilitate blind 3D-IQM. Furthermore, the proposed metric does not require distorted samples or human subjective opinion scores for training. More specifically, the binocular quality-predictive features of areas V1 and V2 are first extracted from a corpus of pristine natural 3D images. Subsequently, a pristine multivariate Gaussian (MVG) model is trained from the extracted features. Finally, with the trained MVG model, the quality of distorted 3D images is measured using a Mahalanobis distance. Experimental results using two public benchmark 3D databases show that in comparison with current state-of-the-art IQM metrics, the proposed metric achieves excellent prediction performance. [ABSTRACT FROM AUTHOR]

In this paper, a novel reduced-reference stereoscopic image quality assessment (RR-SIQA) algorithm is proposed by means of an unconventional use of watermarking technique. Watermarking techniques are usually employed for authenticity verification and copyright protection. Here, watermarking technique is adopted to provide a new approach for RR-SIQA. Firstly, the features of image are extracted in reorganized discrete cosine transform domain, and then embedded into the stereoscopic image as invisible hidden information. In order to improve the reliability of the watermarking, some channel coding techniques are applied before the process of embedding watermark. At the receiver, the watermark can be decoded and used to measure the quality of the distorted stereoscopic image. The proposed algorithm overcomes the limitations of other existing methods that require an auxiliary channel. Experimental results illustrate that the proposed algorithm has a good consistency with subjective quality scores, and can reflect the visual perception of stereoscopic image effectively. [ABSTRACT FROM AUTHOR]

The transparent colloidal solutions of monodisperse CeO2-based quantum dots (QDs) were prepared by heating a triethylene glycol (TEG) solution of Ce(NO3)3⋅6 H2O (and Fe(NO3)3⋅9 H2O) at 180 °C. The CeO2-based QDs were characterized by X-ray powder diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), UV/vis absorption spectra and Brunauer-Emmett-Teller (BET) surface area. CeO2-based QDs with uniform particle size below 5 nm exhibit narrow size distribution, quantum effect, good re-dispersion ability and high surface area. For the formation of these QDs, a polyol-hydrolysis mechanism is proposed. CeO2 QDs are applied in fuel borne catalysts (FBCs) for diesel soot combustion, which exhibit excellent activity at a rather low temperature, owing to the homogeneous and large number of contact points between the catalyst and the soot. The doping with Fe can further improve the selectivity to CO2. [ABSTRACT FROM AUTHOR]

Abstract: The soot combustion on Cr-doped CeO2 mixed oxides was studied. The catalysts were characterized by X-ray powder diffraction, N2 adsorption/desorption, X-ray photoelectron spectroscopy and temperature-programmed reduction with H2. The active sites were quantified using isothermal anaerobic titrations with soot as the probe molecule. The turnover frequency (TOF) was calculated and used to evaluate the activity. The samples with a Cr/(Cr+Ce) ratio within 1–3at.% show an improved activity on the basis of reaction rates and TOF values. The active sites were determined to be composed of Ce–O–Ce species, which is a little more active compared with CeO2 due to the promotion by the doping of Cr. Although the similar reaction rates were observed, the doping of 5 at.% Cr results in a detectable decrease of the TOF compared with CeO2. This is because the active sites are composed of Cr–O–Ce species. The strong interaction of the supported CrO x species with CeO2 results in an increase in the activity of Cr2O3. The promotional effect of Fe to CeO2 on soot combustion is more significant than that of Cr. The TOF is strongly recommended to be the basis of the activity comparison. [Copyright &y& Elsevier]

Abstract: Rare-earth doped CeO2 solid solution nanorods were successfully prepared via a simple co-precipitation method without surfactants at room temperature and pressure. The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of the doping contents, pH values, aging times and the precipitation agents on the structure and morphology were investigated. We found that the yield and uniformity of the nanorods were significantly improved by doping with optimum contents of Nd, Sm, Eu, Gd or Y. The intrinsically anisotropic structure of the rare-earth hydroxides is the driving force for the growth of the nanorods. Raman spectra show a great increase in oxygen vacancy concentrations on the doped CeO2 solid solutions compared with that of pure CeO2. [ABSTRACT FROM AUTHOR]

• The Cu 2 O, Cu 2 O-CuO and CuO (S1-S3) were obtained by a surface restructuring method. • S2 has 100% CO conversion at lower temperatures relative to S1 and S3. • The better activity of S2 is due to the interplay of mixed Cu states (Cu2+ and Cu+). • It can be extended to other potential nanostructures with multiple valence states. In this work, a series of Cu-based samples have been obtained via a controllable surface restructuring method, including cubic Cu 2 O (S1), CuO-Cu 2 O (S2) and irregular CuO nanosheets (S3). Notably, S2 samples possess more superior catalytic activities towards CO oxidation than S1 and S3, even better than that of Cu 2 O cubes with in-situ CuO films during CO oxidation. This observation can be mainly attributed to the interplay between Cu 2 O and CuO in S2. The lattice oxygens provided by CuO are the preferred adsorption sites for CO molecules, then the generated oxygen vacancies could be refilled by O adatoms dissociated from Cu 2 O. [ABSTRACT FROM AUTHOR]

This study describes the preparation and characterisation of MIL-53(Fe) and its effect on the performance of forward osmosis (FO) membranes. The cellulose acetate (CA)/MIL-53(Fe) hybrid membranes were fabricated using the method of phase inversion by dispersing MIL-53(Fe) in a CA casting solution. To improve the selectivity and permeability performance of FO membranes, the effects of MIL-53(Fe) content, casting solution temperature, coagulation bath temperature, and annealing temperature were studied. Results from scanning electron microscopy, membrane porosity, atomic force microscopy, and water contact angle tests of all the membranes show that the structural properties of the CA/MIL-53(Fe) hybrid membranes were optimised. The results of the FO performance tests, including the values of water flux and reverse salt flux, indicate improvement in the selectivity and permeability properties of the CA/MIL-53(Fe) hybrid membranes. Under the conditions of deionised water as the feed solution and 1 M NaCl solution as the draw solution, the water flux and reverse salt flux of the CA/MIL-53(Fe) hybrid membranes reached 34.9 L/(m2·h) and 2.02 g/(m2·h), respectively, in comparison with CA membranes. This study demonstrates that MIL-53(Fe) can improve the desalination performance and structural properties of FO membranes. • MIL-53(Fe) with high porosity was used to fabricate cellulose acetate (CA)/MIL-53(Fe) hybrid membranes for the first time. • Optimal experimental conditions of CA/MIL-53(Fe) hybrid membranes were conducted. • The water flux and reverse salt flux of CA/MIL-53(Fe) hybrid membranes were improved compared to CA membranes. • Effect of MIL-53(Fe) on structural properties of CA membranes was widely discussed. [ABSTRACT FROM AUTHOR]