Double-shell CeO2:Yb, Er@SiO2@Ag upconversion composite nanofibers as an assistant layer enhanced near-infrared harvesting for dye-sensitized solar cells

Double-shell CeO2:Yb,Er@SiO2@ Ag upconversion composite nanofibers are synthesized by electro- spinning and subsequent process. CeO2:Yb,Er@SiO2@ Ag nanofibers show high upconversion luminescence property due to the coating of amorphous SiO2 and the surface plasmon resonance effect of Ag nanoparticles. CeO2:Yb,Er@SiO2@ Ag nanofibers act as an assistant layer in dye-sensitized solar cells (DSSCs) and enhance the photoelectric conversion efficiency (PCE) to 8.17%. The photocurrent-voltage characteristic is obtained under 980 nm laser as illumination light source. In addition, the absorption of the incident photon-to-current conversion efficiency curve in 900-1000 nm near-infrared light confirms that the introduction of the upconversion nanomaterial broadens the absorption range, improves the utilization rate of the sunlight and increases the PCE of DSSCs. (C) 2018 Elsevier B.V. All rights reserved

Synthesis of carbon-supported PdSn–SnO2 nanoparticles with different degrees of interfacial contact and enhanced catalytic activities for formic acid oxidation

The conjunction of the PdSn alloy and SnO2 is of interest for improving catalytic activity in formic acid oxidation (FAO). Here, we report the synthesis of PdSn–SnO2 nanoparticles and a study of their catalytic FAO activity. Different degrees of interfacial contact between SnO2 and PdSn were obtained using two different stabilizers (sodium citrate and EDTA) during the reduction process in catalyst preparation. Compared to the PdSn alloy, PdSn–SnO2 supported on carbon black showed enhanced FAO catalytic activity due to the presence of SnO2 species. It was also found that interfacial contact between the PdSn alloy and the SnO2 phase has an impact on the activity towards CO oxidation and FAO.Web of Scienc

Nanoparticulate TiO2-promoted PtRu/C catalyst for methanol oxidation: TiO2 nanoparticles promoted PtRu/C catalyst for MOR

To improve the electrocatalytic properties of PtRu/C in methanol electrooxidation, nanoparticulate TiO2-promoted PtRu/C catalysts were prepared by directly mixing TiO2 nanoparticles with PtRu/C. Using cyclic voltammetry, it was found that the addition of 10 wt% TiO2 nanoparticles can effectively improve the electrocatalytic activity and stability of the catalyst during methanol electro-oxidation. The value of the apparent activation energy (Ea) for TiO2-PtRu/C was lower than that for pure PtRu/C at a potential range from 0.45 to 0.60 V. A synergistic effect between PtRu and TiO2 nanoparticles is likely to facilitate the removal of CO-like intermediates from the surface of PtRu catalyst and reduce the poisoning of the PtRu catalysts during methanol electrooxidation. Therefore, we conclude that the direct introduction of TiO2 nanoparticles into PtRu/ C catalysts offers an improved facile method to enhance the electrocatalytic performance of PtRu/C catalyst in methanol electrooxidation.Web of Scienc

An ontological characterization of time-series and state-sequences for data mining

Time-series and sequences are important patterns in data mining. Based on an ontology of time-elements, this paper presents a formal characterization of time-series and state-sequences, where a state denotes a collection of data whose validation is dependent on time. While a time-series is formalized as a vector of time-elements temporally ordered one after another, a state-sequence is denoted as a list of states correspondingly ordered by a time-series. In general, a time-series and a state-sequence can be incomplete in various ways. This leads to the distinction between complete and incomplete time-series, and between complete and incomplete state-sequences, which allows the expression of both absolute and relative temporal knowledge in data mining

J. Mater. Cycles Waste Manag.

A new way to implement the simultaneous reutilization of solid waste, the desulfurization of coke oven gas (COG), and even the desulfurization of coke by the co-coking of coking coal (CC) and waste plastic (WP) blended with a sorbent is proposed; the evolution of H2S and the removal efficiency of H2S from COG during the co-coking process were investigated in a lab-scale cylindrical reactor. The experimental results indicated that for the coking of CC blended with ZnO, Fe2O3, or blast furnace dust (BFD) as a sorbent, the instantaneous concentration of H2S in COG was lower than 500 mg/m(3) (which meets the technical specification requirement of the Chinese Cleaner Production Standard-Coking Industry, HJ/T 126-2003) when the molar ratio between the key component of the sorbent and the volatile S in CC or the CC/WP blend, n(Zn+Fe)/nS, was about 1.2 for ZnO and Fe2O3, but not for BFD under the same conditions, suggesting that ZnO and Fe2O3 are promising sorbents, but that BFD must be treated chemical or thermally before being used as a sorbent because of the size and complicated nature of the influence of its phase/chemical composition on its desulfurization ability. However, for the co-coking of CC and WP blended with ZnO as a sorbent, n(Zn+ Fe)/nS must increase to 1.4 and 1.7 for 100/2 and 100/5 blends of CC/WP, respectively, to ensure a satisfactory efficiency for H2S removal from COG.A new way to implement the simultaneous reutilization of solid waste, the desulfurization of coke oven gas (COG), and even the desulfurization of coke by the co-coking of coking coal (CC) and waste plastic (WP) blended with a sorbent is proposed; the evolution of H2S and the removal efficiency of H2S from COG during the co-coking process were investigated in a lab-scale cylindrical reactor. The experimental results indicated that for the coking of CC blended with ZnO, Fe2O3, or blast furnace dust (BFD) as a sorbent, the instantaneous concentration of H2S in COG was lower than 500 mg/m(3) (which meets the technical specification requirement of the Chinese Cleaner Production Standard-Coking Industry, HJ/T 126-2003) when the molar ratio between the key component of the sorbent and the volatile S in CC or the CC/WP blend, n(Zn+Fe)/nS, was about 1.2 for ZnO and Fe2O3, but not for BFD under the same conditions, suggesting that ZnO and Fe2O3 are promising sorbents, but that BFD must be treated chemical or thermally before being used as a sorbent because of the size and complicated nature of the influence of its phase/chemical composition on its desulfurization ability. However, for the co-coking of CC and WP blended with ZnO as a sorbent, n(Zn+ Fe)/nS must increase to 1.4 and 1.7 for 100/2 and 100/5 blends of CC/WP, respectively, to ensure a satisfactory efficiency for H2S removal from COG

Aging properties of the lifetime in simple additive degradation models

National Natural Science Foundation of China [10771090]This paper deals with the simple additive degradation models with single random effect. The authors further study the link between the aging property of the implied lifetime and that of the random variation. It is found that both the aging property of the random variation and the analytical behavior of the mean degradation path influence the aging behavior of the implied lifetime

Event models for tumor classification with SAGE gene expression data

Serial Analysis of Gene Expression (SAGE) is a relatively new method for monitoring gene expression levels and is expected to contribute significantly to the progress in cancer treatment by enabling a precise and early diagnosis. A promising application of SAGE gene expression data is classification of tumors. In this paper, we build three event models (the multivariate Bernoulli model, the multinomial model and the normalized multinomial model) for SAGE data classification. Both binary classification and multicategory classification are investigated. Experiments on two SAGE datasets show that the multivariate Bernoulli model performs well with small feature sizes, but the multinomial performs better at large feature sizes, while the normalized multinomial performs well with medium feature sizes. The multinomial achieves the highest overall accuracy

Ind. Eng. Chem. Res.

With humic acid ( HA) as a special additive, modified Ca( OH)(2) sorbents referred to as M-Ca( OH)(2)-iHA, where i is the weight percentage of HA in the dry product and is in the range between 0 to 10, were prepared by hydrating CaO with water in which the expected amount of HA had been dissolved. The physicochemical properties of the sorbents were characterized using SEM, XRD, BET, etc., and the desulfurization activity of the sorbents, expressed as "Ca utilization", was investigated in a differential fixed-bed quartz reactor under isothermal conditions at 65 degrees C and 70% relative humidity. The experimental results indicate that both hydration treatment and HA modification play important roles in improving the microstructure and desulfurization activity of M-Ca( OH)(2)-iHA. In particular, hydration treatment is the key contribution to M-Ca( OH)(2)-0HA, whereas both factors are significant for M-Ca( OH) 2-iHA ( i) 4, 6, 8, 10). It was also found that the microstructure and desulfurization activity of M-Ca( OH)(2)-iHA improves considerably as i increases from 0 to 8 and then levels out when i increases further to 10. That is, M-Ca( OH)(2)-0HA has almost the optimal microstructure among the sorbents prepared in this study, i. e., volume mean diameter of 0.5 Am, BET surface area of 19.29 m(2)/g, and mesopore volume of 0.084 cm(3)/g, as well as the highest desulfurization activity, Ca utilization of 0.52 mol of SO2/mol of Ca. In addition, the mechanism of HA modification might be due to the acceleration effect of HA on the dissolution of lime, as well as the disturbance effect of Ca2+-HA chelates on the nucleation and growth processes of Ca( OH)(2) crystals.With humic acid ( HA) as a special additive, modified Ca( OH)(2) sorbents referred to as M-Ca( OH)(2)-iHA, where i is the weight percentage of HA in the dry product and is in the range between 0 to 10, were prepared by hydrating CaO with water in which the expected amount of HA had been dissolved. The physicochemical properties of the sorbents were characterized using SEM, XRD, BET, etc., and the desulfurization activity of the sorbents, expressed as "Ca utilization", was investigated in a differential fixed-bed quartz reactor under isothermal conditions at 65 degrees C and 70% relative humidity. The experimental results indicate that both hydration treatment and HA modification play important roles in improving the microstructure and desulfurization activity of M-Ca( OH)(2)-iHA. In particular, hydration treatment is the key contribution to M-Ca( OH)(2)-0HA, whereas both factors are significant for M-Ca( OH) 2-iHA ( i) 4, 6, 8, 10). It was also found that the microstructure and desulfurization activity of M-Ca( OH)(2)-iHA improves considerably as i increases from 0 to 8 and then levels out when i increases further to 10. That is, M-Ca( OH)(2)-0HA has almost the optimal microstructure among the sorbents prepared in this study, i. e., volume mean diameter of 0.5 Am, BET surface area of 19.29 m(2)/g, and mesopore volume of 0.084 cm(3)/g, as well as the highest desulfurization activity, Ca utilization of 0.52 mol of SO2/mol of Ca. In addition, the mechanism of HA modification might be due to the acceleration effect of HA on the dissolution of lime, as well as the disturbance effect of Ca2+-HA chelates on the nucleation and growth processes of Ca( OH)(2) crystals