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排序方式: 共有135条查询结果,搜索用时 937 毫秒
1.
Jui‐Ming Yeh Chi‐Lun Chen Tai‐Hung Kuo Wen‐Fen Su Hsi‐Ya Huang Der‐Jang Liaw Hsin‐Yi Lu Chi‐Fong Liu Yuan‐Hsiang Yu 《应用聚合物科学杂志》2004,92(2):1072-1079
A series of polymer–clay nanocomposite (PCN) materials consisting of 1,4‐bis(4‐aminophenoxy)‐2‐tert‐butylbenzene–4,4′‐oxydiphthalic anhydride (BATB–ODPA) polyimide (PI) and layered montmorillonite (MMT) clay were successfully prepared by an in situ polymerization reaction through thermal imidization up to 300°C. The synthesized PCN materials were subsequently characterized by Fourier‐Transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of material composition on thermal stability, mechanical strength, molecular permeability and optical clarity of bulk PI and PCN materials in the form of membranes were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), molecular permeability analysis (GPA) and ultraviolet‐visible (UV/VIS) transmission spectra, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1072–1079, 2004 相似文献
2.
Jui‐Ming Yeh Chi‐Lun Chen Yen‐Chen Chen Chin‐Yi Ma Hsi‐Ya Huang Yuan‐Hsiang Yu 《应用聚合物科学杂志》2004,92(1):631-637
A series of polymer–clay nanocomposite (PCN) materials containing polysulfone (PSF) and layered MMT clay were successfully prepared by effectively dispersing inorganic nanolayers of MMT clay in an organic PSF matrix via a solution dispersion technique. The synthesized PCN materials were subsequently investigated with a series of characterization techniques, including Fourier transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The prepared PCN coatings with low clay loading (1 wt %) on cold‐rolled steel (CRS) were found to be superior in corrosion prevention to those of bulk PSF, based on a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current and electrochemical impedance spectroscopy (EIS) in a 5 wt % aqueous NaCl electrolyte. The effects of material composition on the molecular barrier, mechanical strength and optical clarity of PSF and PCN materials, in the form of membranes, was also studied by molecular permeability analysis (GPA), dynamic mechanical analysis (DMA) and UV‐Visible transmission spectra, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 631–637, 2004 相似文献
3.
Abstract: Cancer classification, through gene expression data analysis, has produced remarkable results, and has indicated that gene expression assays could significantly aid in the development of efficient cancer diagnosis and classification platforms. However, cancer classification, based on DNA array data, remains a difficult problem. The main challenge is the overwhelming number of genes relative to the number of training samples, which implies that there are a large number of irrelevant genes to be dealt with. Another challenge is from the presence of noise inherent in the data set. It makes accurate classification of data more difficult when the sample size is small. We apply genetic algorithms (GAs) with an initial solution provided by t statistics, called t‐GA, for selecting a group of relevant genes from cancer microarray data. The decision‐tree‐based cancer classifier is built on the basis of these selected genes. The performance of this approach is evaluated by comparing it to other gene selection methods using publicly available gene expression data sets. Experimental results indicate that t‐GA has the best performance among the different gene selection methods. The Z‐score figure also shows that some genes are consistently preferentially chosen by t‐GA in each data set. 相似文献
4.
Chung‐Hsi Chou Sheng‐Yao Wang Yi‐Tsen Lin Yi‐Chen Chen 《International Journal of Food Science & Technology》2014,49(7):1654-1662
This study was divided into two parts: (i) an optimal hydrolysing procedure of chicken liver hydrolysates (CLHs) and (ii) the in vivo antioxidant properties of CLHs via a D‐galactose‐induced mouse model. A pepsin‐to‐raw chicken liver mass ratio (1:400, w:w) and 2‐h hydrolysing period were chosen to manufacture CLHs based on yield, peptide level and antioxidant effect. Molecular masses of CLHs were lower than 10 kDa. CLH was rich in aspartic acid and glutamic acid, and also contained both manganese and selenium, which are essential cofactors of superoxide dismutase and glutathione peroxidase, respectively. The contents of cadmium, mercury, tin, and arsenic in CLHs were very low and even no detectible. Regarding the in vivo antioxidant activity of CLHs, a dosage of 1.2 g D‐galactose kg?1 body weight increased (P < 0.05) 2‐thiobarbituric acid reactive substances values and decreased (P < 0.05) glutathione and Trolox equivalent antioxidant capacity values, as well as superoxide dismutase, catalase, and glutathione peroxidase activities in serum and organs of mice. However, the in vivo antioxidant capacities were improved (P < 0.05) by supplementing CLHs. 相似文献
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A generalized correlation for saturated liquid densities of pure compounds, based on the Guggenheim equation, has been extended for applications to mixtures. The method employs a mole-average acentric factor and scaling volume, and a weighted average critical temperature for the mixture. The method was tested on twenty-four binary and two ternary systems comprising hydrocarbons and non-hydrocarbons. Overall average absolute deviation in predicted densities is less than two percent for a total of 1,096 data points. 相似文献
8.
Pao-Hsiang Hsi Shi-Lin Chen Ray-Jong Li 《Power Systems, IEEE Transactions on》1999,14(2):452-459
The analysis of railway power supplies (RPS) presents a unique type of load flow problem which is characterized by its constant moving loads, dynamically changing load types (constant current/constant power), and its specialized network structure. When multiple trains and the capacitors for power factor correction are also involved, the analysis of this special kind of power system can be very complicated and time consuming which will prevent on-line state analysis from becoming possible. This paper presents a novel and extremely efficient algorithm to solve this special kind of power flow problem with high precision. By first decoupling the autotransformer (AT) current into 2 equal phasor components and then applying an iteration-based circuit-analysis approach, the RPS power flow problem can be solved in an accurate but extremely efficient manner. An on-line railway power-supply state analyzer (RPSA) based on this approach is presented in this paper while the extension of using this approach to perform power factor corrector (PFC) simulation is also presented 相似文献
9.
The electromagnetic coupling to a conducting wire behind an aperture in a plane conducting screen is analyzed. The aperture can be of arbitrary size and shape. The wire can be of finite length, with or without terminating loads, or of infinite length. The electric current on the wire and the equivalent magnetic current over the aperture region are calculated by the method of moments. An equivalent circuit for the effect of the aperture on the transmission line mode of the wire is derived. 相似文献
10.
Ozonation of complex industrial park wastewater: effects on the change of wastewater characteristics
Jen‐Mao Fanchiang Dyi‐Hwa Tseng Gia‐Luen Guo Hsi‐Jien Chen 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(7):1007-1014
BACKGROUND: Ozonation of complex industrial park wastewater was carried out in a semi‐batch reactor. The variation of wastewater characteristics was evaluated based on the analysis of 5‐day biochemical oxygen demand (BOD5) concentration, BOD5/chemical oxygen demand (COD) ratio, COD fractionation, and dissolved organic carbon (DOC) molecular size distribution before and after ozonation. RESULTS: The experimental results indicated that low efficiency of COD removal with increasing tendency of BOD5 concentration generally appeared after ozonation. Also, the BOD5/COD ratio increased from an initial of 0.27 to a maximum of 0.38. The COD fractionation tests revealed that most of the inert soluble COD was transformed to biodegradable soluble COD at 30 min of reaction time. Additionally, the DOC molecular size distribution tests showed that the fraction larger than 500 kDa was significantly decreased and the fraction smaller than 2 kDa was increased when the reaction time was prolonged to 240 min. CONCLUSION: This study verified that partial oxidation of the complex industrial park wastewater by ozonation could enhance wastewater biodegradability. The biodegradability enhancement was primarily because the inert soluble COD fraction was converted to the biodegradable soluble COD and the high molecular weight fraction of DOC was shifted toward the low molecular weight fraction. Copyright © 2009 Society of Chemical Industry 相似文献