排序方式: 共有59条查询结果,搜索用时 15 毫秒
21.
I-Ming Hung Yen-Juin Chiang Yi-Hung Wang Jason S.C. Jang Sheng-Wei Lee 《International Journal of Hydrogen Energy》2017,42(34):22149-22158
In this study, Sr(Ce0.6Zr0.4)1?xYxO3?δ (x = 0.1, 0.15, 0.2, 0.25, 0.3, SCZY) perovskite proton-conducting ceramics were synthesized using the citrate-ethylenediaminetetraacetic acid complexing method. The effect of the Y concentration on the crystal structure, electrochemical performance and hydrogen flux of the SCZY samples in air and a H2 atmosphere were investigated. The sintered SCZY samples showed a main perovskite crystal structure with several SrY2O4 impurity phases when x ≥ 0.20. The grain size of SCZY samples when x = 0.25 and 0.30 was smaller than that of other samples. The conductivity of all samples increased as the temperature increased in both air and H2; however, the conductivity of SCZY in H2 was lower than that in air. The results of AC impedance, demonstrated that resistance mainly derived from the charge transfer, which was apparently higher than the bulk and grain boundary resistance. Sr(Ce0.6Zr0.4)0.85Y0.15O3-δ exhibited low charge transfer resistance in both air and the H2 atmosphere and had a high hydrogen flux of 0.34 ml min?1 cm?2 μm?1 at 800 °C. The structures of all SCZY samples were stable in 80 °C water. 相似文献
22.
CO(2) sequestration by the aqueous carbonation of steel-making slag under various operational conditions was investigated in this study. The effects of the operational conditions, including type of steel-making slag, reaction time, reaction temperature, and CO(2) flow rate, on the performance of the carbonation process were evaluated. The results indicated that the BOF slag had the highest carbonation conversion, approximately 72%, at a reaction time of 1h, an operating pressure of 101 kPa and a temperature of 60°C due to its higher BET surface area of BOF slag compared to UF, FA, and BHC slags. The major factors affecting the carbonation conversion are reaction time and temperature. The reaction kinetics of the carbonation conversion can be expressed by the shrinking-core model. The measurements of the carbonated material by the SEM and XRD instruments provide evidence indicating the suitability of using the shrinking-core model in this investigation. Comparison of the results with other studies suggests that aqueous carbonation by slurry reactor is viable due to its higher mass transfer rate. 相似文献
23.
Biodiesel derived from free fatty acids (FFAs), which has the advantage of not competing with the edible-oil market, exhibited poor oxidation stability. The induction period (IP) of the FFA-based biodiesel determined by the Rancimat method at 110 °C was 0.20 h. This study investigates the effectiveness of one natural and ten synthetic antioxidants, including α-tocopherol (α-T); butylated hydroxyanisole (BHA); butylated hydroxytoluene (BHT); 2, 5-di-tert-butylhydroquinone (DTBHQ); Ethanox 4740; Ethanox 4760E; 2,2′-methylene-bis-(4-methyl-6-tert-butylphenol) (MBMTBP); N,N′-di-sec-butyl-p-phenylenediamine (PDA); propyl gallate (PG); pyrogallol (PY); and tert-butylhydroquinone (TBHQ), at concentrations between 100 and 1000 ppm to improve the oxidation stability of the FFA-based biodiesel. The order of antioxidant effectiveness with respect to the oxidation stability of the FFA-based biodiesel was PY > Ethanox 4760E > PG > Ethanox 4740 > PDA ~ BHA > BHT > MBMTBP ~ TBHQ > DTBHQ > α-T. The IP of the FFA-based biodiesel increased as the antioxidant concentration was increased and decreased at high test temperatures. Furthermore, the relationship between the IP values associated with the consumption of antioxidants in the FFA-based biodiesel was described by first-order reaction rate kinetics. However, the natural logarithm of IP (ln IP) at various concentrations of Ethanox 4760E showed a linear relation with the test temperature. The IP at ambient temperature was predicted based on the extrapolation method of the temperature dependence relation. After long-term storage at room temperature, the IP and acid value of the original FFA-based biodiesel significantly decreased and increased, respectively, with storage time, while the addition of antioxidants ensured the oxidation stability of the FFA-based biodiesel over 6 months of storage. 相似文献
24.
This study investigates the photocatalytic degradation of dimethyl phthalate (DMP) with both the titanium dioxide-coated magnetic poly(methyl methacrylate) (TiO2/mPMMA) and platinum-doped TiO2/mPMMA (Pt–TiO2/mPMMA) microspheres. The TiO2/mPMMA and Pt–TiO2/mPMMA microspheres are employed as novel photocatalysts that offer high photocatalytic activity, magnetic separability and good durability. The photocatalytic experiments of DMP under various conditions are conducted to examine the effects of the initial DMP concentration, photocatalyst dosage, UV radiation intensity and Pt doping content on the degradation of DMP. In addition, the correlations of the photocatalytic kinetics and quantum yield for DMP removal are proposed associated with the system parameters. According to the experimental results, there exists a distinct relationship between the reduction percentages of total organic carbons and DMP. Furthermore, the photodegradation mechanism of DMP in the photocatalytic process is established based on the identification of the intermediates. Moreover, the good repeatability of the photocatalytic performance with the use of the Pt–TiO2/mPMMA microspheres has also been demonstrated in the multi-run experiments. Therefore the Pt–TiO2/mPMMA microspheres are considered as a practical and promising photocatalyst in a suspension reaction system and they can be effectively recovered after use. This study provides useful information about the applications of the TiO2/mPMMA and Pt–TiO2/mPMMA microspheres for the photodegradation of DMP. 相似文献
25.
This study investigates the photocatalytic degradation of p-phenylenediamine (PPD) with titanium dioxide-coated magnetic poly(methyl methacrylate) (TiO2/mPMMA) microspheres. The TiO2/mPMMA microspheres are employed as novel photocatalysts with the advantages of high photocatalytic activity, magnetic separability, and good durability. The scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and transmission electron microscopy (TEM) images of the TiO2/mPMMA microspheres are used to characterize the morphology, element content, and distribution patterns of magnetite and TiO2 nanoparticles. The BET-specific surface area and saturation magnetization of the TiO2/mPMMA microspheres are observed as 2.21 m(2)/g and 4.81 emu/g, respectively. The photocatalytic degradation of PPD are performed under various experimental conditions to examine the effects of initial PPD concentration, TiO2/mPMMA microsphere dosage, and illumination condition on the eliminations of PPD and chemical oxygen demand (COD) concentrations. Good repeatability of photocatalytic performance with the use of the TiO2/mPMMA microspheres has been demonstrated in the multi-run experiments. The photocatalytic kinetics for the reductions of PPD and COD associated with the initial PPD concentration, UV radiation intensity, and TiO2/mPMMA microsphere dosage are proposed. The relationships between the reduction percentages of COD and PPD are clearly presented. 相似文献
26.
With the advantages of being easy to understand and efficient to compute, the decision tree method has long been one of the most popular classifiers. Decision trees constructed with existing approaches, however, tend to be huge and complex, and consequently are difficult to use in practical applications. In this study, we deal with the problem of tree complexity by allowing users to specify the number of leaf nodes, and then construct a decision tree that allows maximum classification accuracy with the given number of leaf nodes. A new algorithm, the Size Constrained Decision Tree (SCDT), is proposed with which to construct a decision tree, paying close attention on how to efficiently use the limited number of leaf nodes. Experimental results show that the SCDT method can successfully generate a simpler decision tree and offers better accuracy. 相似文献
27.
Li-Ren Hsu Yaw-Bin Huang Pao-Chu Wu Yi-Hung Tsai 《Drug development and industrial pharmacy》1994,20(6):1093-1101
The effects of the administration for a commercial keto-profen gel on the percutaneous absorption of ketoprofen (through rabbit abdominal skin) were investigated. The AUC (area under the curve) value of absorbed ketoprofen for single topical administration of 6 g of ketoprofen gel applied with ODT (occlusive dressing technique) was found to be about 6 -fold greater than that of repeated administration of 1.5 g of ketoprofen gel applied with ODT at 6 h interval in a day. It was about 14-fold greater than that of repeated administration of 1.5 g of ketoprofen gel applied without ODT at 6 h interval in a day. The experiment of volatilation of ketoprofen gels and the in vitro release test of ketoprofen gel applied with ODT and without ODT had been, in addition, respectively approached. The volatilation of solvent in the gel, as a result of this, may clearly be the primary factor for inducing a sharp descending of the plasma ketoprofen level following the Cmax (maximun concentration) in the in vivo percutaneous absorption of ketoprofen gel: this factor also results in a lower plasma ketoprofen level for the gel applied without ODT than that with ODT. 相似文献
28.
Po-Yi Shih Anand Paul Jhing-Fa Wang Yi-Hung Chen 《Multimedia Tools and Applications》2014,73(1):417-437
This paper presents a real-time speech-driven talking face system which provides low computational complexity and smoothly visual sense. A novel embedded confusable system is proposed to generate an efficient phoneme-viseme mapping table which is constructed by phoneme grouping using Houtgast similarity approach based on the results of viseme similarity estimation using histogram distance, according to the concept of viseme visually ambiguous. The generated mapping table can simplify the mapping problem and promote viseme classification accuracy. The implemented real time speech-driven talking face system includes: 1) speech signal processing, including SNR-aware speech enhancement for noise reduction and ICA-based feature set extractions for robust acoustic feature vectors; 2) recognition network processing, HMM and MCSVM are combined as a recognition network approach for phoneme recognition and viseme classification, which HMM is good at dealing with sequential inputs, while MCSVM shows superior performance in classifying with good generalization properties, especially for limited samples. The phoneme-viseme mapping table is used for MCSVM to classify the observation sequence of HMM results, which the viseme class is belong to; 3) visual processing, arranges lip shape image of visemes in time sequence, and presents more authenticity using a dynamic alpha blending with different alpha value settings. Presented by the experiments, the used speech signal processing with noise speech comparing with clean speech, could gain 1.1 % (16.7 % to 15.6 %) and 4.8 % (30.4 % to 35.2 %) accuracy rate improvements in PER and WER, respectively. For viseme classification, the error rate is decreased from 19.22 % to 9.37 %. Last, we simulated a GSM communication between mobile phone and PC for visual quality rating and speech driven feeling using mean opinion score. Therefore, our method reduces the number of visemes and lip shape images by confusable sets and enables real-time operation. 相似文献
29.
Querying polyphonic music from a large data collection is an
interesting topic. Recently, researchers have attempted to provide efficient methods for content-based retrieval in polyphonic
music databases where queries are polyphonic. However, most of them do not work well for similarity search, which is important
to many applications. In this paper, we propose three polyphonic representations with the associated similarity measures and
a novel method to retrieve k music works that contain segments most similar to the query. In general, most of the index-based methods for similarity search
generate all the possible answers to the query and then perform exact matching on the index for each possible answer. Based
on the edit distance, our method generates only a few possible answers by performing the deletion and/or replacement operations
on the query. Each possible answer is then used to perform exact matching on a list-based index, which allows the insertion
operations to be performed. For each possible answer, its edit distance to the query is regarded as a lower bound of the edit
distances between the matched results and the query. Based on the kNN results that match a possible answer, the possible answers that cannot provide better results are skipped. By using this
mechanism, we design a method for efficient kNN search in polyphonic music databases. The experimental results show that our method outperforms the previous methods in
efficiency. We also evaluate the effectiveness of our method by showing the search results to the musician and nonmusician
user groups. The experimental results provide useful guidelines on the design of a polyphonic music database. 相似文献
30.
Huang YB Chang JS Liu JC Tsai MJ Tsai YH Wu PC 《Drug development and industrial pharmacy》2004,30(2):163-169
In this study, we compared the irritation inhibition of various types of anti-irritants such as antihistamines (cyprohetadine, diphenhydramine, and promethazine), alpha-hydroxy acids (gluconolactone and gluco-δ-lactone), corticosteroids (betamethasone and clobetasol), and ion channel modulating agents (amiloride, ethacrynic acid, nifedipine, and verapamil) on the adverse dermatological reaction caused by captopril gel using noninvasive bioengineering methods including measuring the transepidermal water loss (TEWL) and the color change of skin surface [such as change chroma (delta C) and difference in color (delta E) between the gel-treated site and the untreated site]. In addition, the influence of these anti-irritants on the penetration capacity of captopril through the rabbit skin was also investigated. The results showed that the TEWL, change chroma (delta C), and difference in color (delta E) of skin were significantly reduced via incorporating diphenhydramine and clobetasol, indicating that both substances had potent irritation inhibition activity. Moreover, these substances had no effect on the percutaneous absorption of captopril gel. However, flux of the captopril with anti-irritants was about 480 µg/cm2/h and the required minimum administration area to obtain the minimum effective concentration was about 15 cm2, indicating that this formulation could possibly be developed for a transdermal drug delivery system. 相似文献