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排序方式: 共有2812条查询结果,搜索用时 31 毫秒
161.
Seyed Hamed Aboutalebi Mohsen Moazzami Gudarzi Qing Bin Zheng Jang‐Kyo Kim 《Advanced functional materials》2011,21(15):2978-2988
A novel process is developed to synthesize graphene oxide sheets with an ultralarge size based on a solution‐phase method involving pre‐exfoliation of graphite flakes. Spontaneous formation of lyotropic nematic liquid crystals is identified upon the addition of the ultralarge graphene oxide sheets in water above a critical concentration of about 0.1 wt%. It is the lowest filler content ever reported for the formation of liquid crystals from any colloid, arising mainly from the ultrahigh aspect ratio of the graphene oxide sheets of over 30 000. It is proposed that the self‐assembled brick‐like graphene oxide nanostructure can be applied in many areas, such as energy‐storage devices and nanocomposites with a high degree of orientation. 相似文献
162.
The effect of pH,salts and sugars on the rheological properties of cress seed (Lepidium sativum) gum
Fataneh Behrouzian Seyed M. A. Razavi Hojjat Karazhiyan 《International Journal of Food Science & Technology》2013,48(12):2506-2513
Effect of shear rate (15–600 s?1), gum concentration (1–2%), pH (3–9), sucrose (10–40%), lactose (5–15%), NaCl (100–300 mm ) and CaCl2 (5–50 mm ) was evaluated on apparent viscosity (ηa), flow behaviour index (n), consistency coefficient (K) and yield stress (τ0) indices of cress seed gum (CSG) solutions. Different rheological models were used to fit the experimental data, although the Herschel–Bulkley model was found the best model. An increase in gum concentration led to an increase in τ0, ηa, and k and a decrease in n values. The addition of salts lowered the k value; however, the n value showed slight significant change. The presence of sugar resulted in the enhancement of n, k, τ0 and ηap values. The existence of yield stress and pseudoplastic behaviour of CSG, its stability against salts, wide range of pH and synergic effect of sugar make it a good thickener and stabiliser in food formulations. 相似文献
163.
Due to their non-polluting nature and environment friendliness, Renewable Energies have gained great deal of attention and deserve a substantial body of both theoretical and empirical research. Amongst other factors, the low operational cost and simple maintenance procedures attributed the Oscillating Water Column (OWC) are perhaps the main reasons why this system is the most used concept for the ocean wave energy capture.In this paper, through extensive experimental research various geometrical designs of an OWC system is investigated and the optimized set up for the maximum energy harness is obtained.The initial chamber dimensions were 10 × 50 × 53 cm with the chamber being placed in an open channel with wave-simulating equipment with dimensions of 16 × 0.7 × .05 m. For various chamber geometries, with the aid of a air rotameter and a Pitot tube equipped with a digital manometer, the outlet air flow and velocity from the chamber was measured and registered.The measurements were then interpreted to provide design data for the optimal geometry of the chamber that may yield the maximum conversion of wave energy to useful energy. 相似文献
164.
A series of polyaniline (PANI)/montmorillonite (MMT) nanocomposite materials has been successfully prepared by in-situ emulsion polymerization in the presence of inorganic nanolayers of clay with camphorsulfonic acid (CSA) and ammonium peroxydisulfate (APS) as surfactant and initiator, respectively. The nanocomposite materials were characterized by Fourier Transformation Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Epoxy resin was used as a binder for the nanocomposites in order to obtain a thick and uniform coating. In order to understand the effect of MMT and PANI on the corrosion inhibition performance of the epoxy coatings in 3.5% saline solution at 65 °C, the epoxy (E), epoxy blend with polyaniline (EP), epoxy blend with polyaniline and MMT (EPM) coatings were investigated by electrochemical impedance spectroscopy (EIS). The results showed that EPM coatings with 5% clay on pretreated aluminum by anodizing were much superior in corrosion protection, with respect to the other samples. Incorporation of PACN nanocomposites inside the epoxy significantly increases the resistance of the coating in comparison to the other coatings in 3.5% saline solution at 65 °C. These phenomena can be attributed to specific morphology of the nanocomposite. 相似文献
165.
Sharif Shahbeyk Morteza Hosseini Mohammadreza Yaghoobi 《Computational Materials Science》2011,50(7):1973-1990
The present paper studies the failure of concrete from the mesoscopic point of view. Biphasic cubic concrete samples containing spherical aggregates embedded in a homogenized mortar have been simulated using standard finite element method. Linear elasticity and damage-plasticity hypotheses are considered for the aggregates and mortar, respectively. Various triaxial loading conditions are assumed for each sample to generate adequate discrete failure points within the stress space. In the next step, the approximated failure surfaces of specimens are constructed using the Delaunay triangulation technique. The effects of mesostructural features such as aggregate grading curve, aggregate volumetric share, and more importantly the controlling parameters of mortar’s damage-plasticity constitutive model have been investigated. Finally, the failure modes of some selected samples have been reported and discussed. 相似文献
166.
Improving Rainfall Forecasting Efficiency Using Modified Adaptive Neuro-Fuzzy Inference System (MANFIS) 总被引:3,自引:2,他引:1
Rainfall is one of the most complicated effective hydrologic processes in runoff prediction and water management. The adaptive neuro-fuzzy inference system (ANFIS) has been widely used for modeling different kinds of nonlinear systems including rainfall forecasting. Adaptive Neuro-Fuzzy Inference Systems (ANFIS) combines the capabilities of Artificial Neural Networks (ANN) and Fuzzy Inference Systems (FIS) to solve different kinds of problems, especially efficient in rainfall prediction. This paper after reconsidering conventional ANFIS architecture brings up a modified ANFlS (MANFlS) structure developed with attention to making ANFIS technique more efficient regarding to Root Mean Square Error (RMSE), Correlation Coefficient (R 2), Root Mean Absolute Error (RMAE), Signal to Noise Ratio (SNR) and computing epoch. The modified ANFIS (MANFIS) architecture is simpler than conventional ANFIS with nearly the same performance for modeling nonlinear systems. In this study, two scenarios were introduced; in the first scenario, monthly rainfall was used solely as an input in different time delays from the time (t) to the time (t-4) to conventional ANFIS, second scenario used the modified ANFIS to improve the rainfall forecasting efficiency. The result showed that the model based Modified ANFIS performed higher rainfall forecasting accuracy; low errors and lower computational complexity (total number of fitting parameters and convergence epochs) compared with the conventional ANFIS model. 相似文献
167.
168.
Seyed Saeed Mirian Alireza Fadaei Seyed Mohsen Safavi Mahmoud Farzin Mahmoud Salimi 《The International Journal of Advanced Manufacturing Technology》2011,55(5-8):601-610
In this research, polishing flat surfaces has been done by using a completely new and innovative method. In this method, rotary magnetic tool that carry magnetic abrasive powders, is placed in a very strong thermal induction field, and magnetic rotary tool frequently change its direction from clockwise (CW) to counterclockwise (CCW) and CCW to CW. The frequency of changing rotation direction is an important parameter of this innovation method. The intended pieces for polishing operations have been placed on a synchronic two-axis Cartesian CNC table, and the gap between rotary magnetic tool and the sheet surface can be controlled by a power transmission screw operating in the direction of the vertical axis. Several experiments have proved high performance of the new proposed method in the process of polishing. 相似文献
169.