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71.
Several fuzzy approaches can be considered for solving multiobjective transportation problem. This paper presents a fuzzy goal programming approach to determine an optimal compromise solution for the multiobjective transportation problem. We assume that each objective function has a fuzzy goal. Also we assign a special type of nonlinear (hyperbolic) membership function to each objective function to describe each fuzzy goal. The approach focuses on minimizing the negative deviation variables from 1 to obtain a compromise solution of the multiobjective transportation problem. We show that the proposed method and the fuzzy programming method are equivalent. In addition, the proposed approach can be applied to solve other multiobjective mathematical programming problems. A numerical example is given to illustrate the efficiency of the proposed approach. 相似文献
72.
Saeid Farhadi Mozhgan Afshari Mansoureh Maleki Zaynab Babazadeh 《Tetrahedron letters》2005,46(49):8483-8486
An efficient, selective and green procedure for the photocatalytic oxidation of primary and secondary benzylic alcohols to the corresponding aldehydes and ketones has been achieved using silica-encapsulated H3PW12O40 as a recyclable heterogeneous photocatalyst in acetonitrile under oxygen gas as the sole reoxidant of the catalyst. 相似文献
73.
74.
Mir Ali?FarajzadehEmail author Mortaza?Ebrahimi Ali?Ranji Elham?Feyz Vali?Bejani Ramin?Maleki 《Mikrochimica acta》2005,150(2):173-177
This study describes the sample preparation and two chromatographic techniques for determination of Tinuvin 622 in polyethylene. The first part of the two methods consisting of dissolving the polyethylene in boiling xylene is followed by addition of a methanolic solution of potassium hydroxide. The polymeric light stabilizer, Tinuvin 622, is thereby saponified to 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (diol). Addition of the methanolic solution of the saponification reagent simultaneously precipitates the polyethylene matrix. Then the diol is quantified using either gas chromatography (GC) or high performance liquid chromatography (HPLC). For GC, a Macherey Nagel Optima-17 capillary column (30m×0.25mm ID, film thickness 0.25µm) is used. Nitrogen is used as carrier gas and make-up gas. The detection system is a flame ionization detector. For HPLC, an octadecyl silane (ODS) column (30cm×4mm, particle size 5µm) and a mobile phase methanol: water mixture (3:97, v/v) are used. Detection of analyte is carried out at 215nm. Both methods can be used to determine Tinuvin 622 in polyethylene in the concentration range of 0.02–1%, which represents the usual application concentration. 相似文献
75.
The design and construction of a modified Z-type flow-through cell that can be used for optical, electrochemical, and optoelectrochemical measurements are reported. In optical analysis, the proposed flow cell is placed in the light path of a spectrophotometer and worked as a commercial Z-type optical flow cell. In electrochemical analysis, the working and auxiliary electrodes are two platinum sheets placed at both ends of the cell cavity; the cell cavity is enclosed by two glass windows. The reference electrode is a saturated calomel electrode placed downstream in an overflow tube. The performance of the proposed electrochemical flow cell was studied by analysis of hexacyanoferrate solution as an electroactive species. In optoelectrochemical analysis, the proposed flow cell is operated optically and electrochemically, simultaneously. The flow cell is placed in the light path of a spectrophotometer, constant potential is applied to the electrodes, and the optical and electrochemical signals are recorded simultaneously by the use of two recorders. 相似文献
76.
Competitive inhibition ELISA for quantification of Ara h 1 and Ara h 2, the major allergens of peanuts 总被引:1,自引:0,他引:1
Allergies to peanuts are becoming an increasingly important health problem as a result of the persistence and severity of the reaction in allergic individuals. Because no treatment currently is available, avoidance is the only option for peanut-allergic individuals. Avoidance of an abundant and often disguised food such as peanuts, however, is very difficult; therefore, competitive inhibition ELISAs were developed to detect and quantitate each of the major peanut allergens, Ara h 1 and Ara h 2. Under optimal conditions for each assay, the sensitivity of the Ara h 1 and Ara h 2 detection assays were 12 and 0.5 ng/mL, respectively. These assays were primarily devised to effectively compare the levels of Ara h 1 and Ara h 2 in a wide variety of peanuts or peanut products but can also be used to identify cross-reactive antigens. The method is simple and rapid, requiring only one allergen-specific antibody and, therefore, could be adapted specifically to detect the presence of these individual allergens in different foods. 相似文献
77.
An artificial neural network (ANN) model is developed for simultaneous determination of Al(III) and Fe(III) in alloys by using chrome azurol S (CAS) as the chromogenic reagent and CCD camera as the detection system. All calibration, prediction and real samples data were obtained by taking a single image. Experimental conditions were established to reduce interferences and increase sensitivity and selectivity in the analysis of Al(III) and Fe(III). In this way, an artificial neural network consisting of three layers of nodes was trained by applying a back-propagation learning rule. Sigmoid transfer functions were used in the hidden and output layers to facilitate nonlinear calibration. Both Al(III) and Fe(III) can be determined in the concentration range of 0.25-4 μg ml−1 with satisfactory accuracy and precision. The proposed method was also applied satisfactorily to the determination of considered metal ions in two synthetic alloys. 相似文献
78.
Preparation and characterization of a silica‐based magnetic nanocomposite and its application as a recoverable catalyst for the one‐pot multicomponent synthesis of quinazolinone derivatives
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An environmentally benign magnetic silica‐based nanocomposite (Fe3O4/SBA‐15) as a heterogeneous nanocatalyst was prepared and characterized using Fourier transform infrared and ultraviolet–visible diffuse reflectance spectroscopies, scanning electron microscopy, X‐ray diffraction, vibrating sample magnetometry and Brunauer–Emmett–Teller multilayer nitrogen adsorption. Its catalytic activity was investigated for the one‐pot multicomponent synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones starting from isatoic anhydride, ammonium acetate and various aldehydes under mild reaction conditions and easy work‐up procedure in refluxing ethanol with good yields. The nanocatalyst can be recovered easily and reused several times without significant loss of catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
79.
Chen Zhixiong Shahrajabian Hamzeh Bagherzadeh Seyed Amin Maleki Alireza Bach Quang-Vu 《Journal of Thermal Analysis and Calorimetry》2020,141(1):421-433
Journal of Thermal Analysis and Calorimetry - This study attempts to develop a high-performance wood plastic composite (WPC) in terms of impact strength, tensile strength, and tensile modulus. For... 相似文献
80.
Azimi Bahareh Maleki Homa Gigante Vito Bagherzadeh Roohollah Mezzetta Andrea Milazzo Mario Guazzelli Lorenzo Cinelli Patrizia Lazzeri Andrea Danti Serena 《Cellulose (London, England)》2022,29(6):3079-3129
Cellulose - Cellulose, a natural, renewable, and environment friendly biopolymer, has been considered as a sustainable feedstock in the near future. However, only 0.3% of cellulose is today... 相似文献