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排序方式: 共有401条查询结果,搜索用时 31 毫秒
101.
Fouzia Nawaz Muhammad Ramzan Khalid Mehmood Hikmat Ullah Khan Saleem Hayat Khan Muhammad Raheel Bhutta 《计算机、材料和连续体(英文)》2021,66(2):1631-1652
Diabetic retinopathy (DR) is a retinal disease that causes irreversible blindness. DR occurs due to the high blood sugar level of the patient, and it is clumsy to be detected at an early stage as no early symptoms appear at the initial level. To prevent blindness, early detection and regular treatment are needed. Automated detection based on machine intelligence may assist the ophthalmologist in examining the patients’ condition more accurately and efficiently. The purpose of this study is to produce an automated screening system for recognition and grading of diabetic retinopathy using machine learning through deep transfer and representational learning. The artificial intelligence technique used is transfer learning on the deep neural network, Inception-v4. Two configuration variants of transfer learning are applied on Inception-v4: Fine-tune mode and fixed feature extractor mode. Both configuration modes have achieved decent accuracy values, but the fine-tuning method outperforms the fixed feature extractor configuration mode. Fine-tune configuration mode has gained 96.6% accuracy in early detection of DR and 97.7% accuracy in grading the disease and has outperformed the state of the art methods in the relevant literature. 相似文献
102.
R. Murugesan S. Sivakumar P. Anandan M. Haris 《Journal of Materials Science: Materials in Electronics》2017,28(17):12432-12439
Pure, Barium and Nickel doped cadmium sulphide (CdS) thin films have been coated on glass substrates at 400?°C by spray pyrolysis technique. The prepared CdS and doped CdS thin films were analysed by various measurements such as X-ray diffraction (XRD), SEM, optical and Vibrating Sample Magnetometer (VSM). X-ray diffraction measurements show that the coated pure, Ba and Ni-doped CdS thin films belong to the cubic crystal structure with orientation preferentially along (111) direction. The average crystallite size of pure, Ba and Ni doped CdS thin films were determined as 31, 33 and 45 nm, respectively. The average dislocation density (δ) and stacking fault (SF) of pure, Ba and Ni doped CdS thin films were also determined. The surface morphology and elemental analysis of the thin films were determined by scanning electron microscopy and energy dispersive X-ray spectrum (SEM with EDAX). It is observed that the optical energy bandgap has been decreased from 2.43 to 2.1 eV due to the doping Ba. The luminescence spectrum shows a strong emission peak at 517 nm in the case of pure CdS thin film and a meager red shift has been observed due to the doping. VSM studies were employed to study the magnetic behaviour of Ba and Ni doped CdS thin films. 相似文献
103.
104.
Andi Haris Nam Seo Goo Hoon Cheol Park Kwang Joon Yoon 《Computational Materials Science》2004,30(3-4):474-481
This paper focuses on the modeling and analysis of Lightweight Piezoceramic Composite Actuators (LIPCA) for developmental purposes. A simple analytical model and a numerical model for predicting the displacement of the actuators due to both an applied input voltage and transverse load to the piezoelectric ceramic layer are presented. The analytical model describing the laminated beam actuation results in two primary design parameters, an actuation coefficient of a laminated beam Culb and the bending stiffness of a laminated beam EIlb. The Culb is a parameter when maximum displacement is required. The bending stiffness affects the displacement performance when a transverse load is applied to the actuators. An experiment was performed to verify the proposed laminated beam model. The numerical model, a NASTRAN finite element model, is used to assess the effect of initial dome heights of actuators on the displacement. An increase in the initial dome height produces a positive effect for the low anisotropic actuators and gives a negative effect for the high anisotropic actuators. In conclusion, the results indicate that designing to maximize the Culb, the EIlb, and the initial dome height of the low anisotropic actuators could generate LIPCA-type actuators with larger displacement and higher force. 相似文献
105.
Tariq Aziz Sahid Mehmood Fazal Haq Roh Ullah Farman Ullah Khan Bakhtar Ullah Muhammad Raheel Mudassir Iqbal Asmat Ullah 《应用聚合物科学杂志》2021,138(40):51191
This research article describes the results of nano-silica composites filled with different epoxy contents containing nano-SiO2 particles from (5–25 wt%). Reinforcing hybrid composites enhance thermal and mechanical properties to achieve vital and sustainable products. Silica-based nanocomposites with high purity were prepared and used for the surface modification of nanosized silica particles. The surface structure's composition and physical properties of modified nano-SiO2 particles were characterized through Fourier transferred infrared spectrometer, X-ray photoelectron spectroscopy, thermogravimetric analyzer, and scanning electron microscopic. Silica-based nanocomposites were prepared by incorporating of modified nano-SiO2 as an enhancing filler. The morphology of fracture surface and dynamic mechanical properties were investigated. Results showed that the silica-based epoxy nanocomposites are bearing a long chain structure that could improve the compatibility of silica nanocomposites with epoxy resin and contribute to a better dispersion state in the matrix, which enhanced the overall performance of epoxy-cured products. 相似文献
106.
Nanocomposite films were obtained by solution casting method from aqueous solution of bovine gelatin with addition of various concentrations of magnetic iron oxide (MIO) nanoparticles (NPs) (5, 10, 15, and 20% w/w of dry gelatin). The incorporation of MIO NPs improved the mechanical and physical properties of the nanocomposites. The increase in concentration of NPs up to 10% improved barrier and mechanical properties which slightly decreased after increasing the concentration beyond that limit due to particle agglomeration. The scanning electron microscopy and X-ray diffraction (XRD) were used to evaluate the morphology and crystalline structure of gelatin nanocomposite films, respectively. Gelatin nanocomposites with 20% w/w NPs exhibited the highest antimicrobial activity against Escherichia coli (7.1 ± 0.085 mm) and Staphylococcus aureus (8.22 ± 1.04 mm). Finally, the potential of gelatin/MIO nanocomposites as packaging material was evaluated to extend the shelf life of grapes. The gelatin/MIO nanocomposites can be used as a replacement to non-biodegradable packaging. 相似文献
107.
108.
Haris Parvez I.; Ramesh Bala; Sansom Mark S. P.; Kerr Ian D.; Srai Kaila S.; Chapman Dennis 《Protein engineering, design & selection : PEDS》1994,7(2):255-262
Recent mutagenesis studies nave identified a stretch of aminoacid residues which form the ion-selective pore of the voltage-gatedpotassium channel. It has been suggested that this sequenceof amino acids forms a ß-barrel structure making upthe structure of the ion-selective pore [Hartman,H.A., Kirsch,G.E.,DreweJ.A., Taglialatela.M., Joho.R.H. and Brown,A.M. (1991)Science, 251, 942944; YeUen.G., Jurman,M.E., Abramson,T.and MacKinnon,R. (1991) Science, 251, 939942; Yool,AJ.and Schwarz.T.L. (1991) Nature, 349, 700704]. We havesynthesized a polypeptide corresponding to this amino add sequence(residues 431449 of the ShA potassium channel from Drosophila).A tetrameric version of this sequence was also synthesized byUnking together four of these peptldes onto a branching lysinecore. Fourier transform infrared (FT-LR) and circular dichroism(CD) spectroscopy have been used to investigate the structureof these peptides after their reconstitution into lyso phos-phatidylcholinemicelles and lipid bilayers composed of dimyristoyl phosphatidyfcholineand dimyristoyl phosphatidyl-glycerol. The spectroscopic studiesshow that these peptides are predominantly a-helical in theselipid environments. When Incorporated into planar lipid bilayersboth peptides induce ion channel activity. Molecular modellingstudies based upon the propensity of these peptides to forman -helical secondary structure in a hydrophobfc environmentare described. These results are discussed in the light of recentmutagenesis and binding studies of the Drosophila Shaker potassiumion channel protein 相似文献
109.
Tahir Mehmood 《IET nanobiotechnology / IET》2021,15(3):309
Co‐surfactant free l‐ascorbic acid (LAA) nanoemulsions were prepared using mixed surfactants (Soya lecithin and Tween 80). Response surface methodology (RSM) was used to optimise the emulsifying conditions for LAA nanoemulsions. The effects of water proportion (6%–14% w/w), homogenisation pressure (80–160 MPa), surfactant concentrations (4%–12% w/w) and laa concentration (0.5–1.3 w/w) on responses (size of droplets and nanoemulsion stability) were investigated. RSM results showed that the values of responses can be successfully predicted through second‐order polynomial model. The coefficients of determinations for droplet size and nanoemulsion stability were 0.9375 and 0.9027, respectively. The optimum preparation conditions for l‐LAA nanoemulsion were 9.04% water proportion, 114.48 MPa homogenisation pressure, 7.36% surfactant concentration and 1.09% LAA concentration. At the end of one month storage study, the retention of LAA in optimised nanoemulsions stored at 4°C and 25°C were 74.4% and 66.7%, respectively. These results may provide valuable contributions for food and pharmaceutical industry to develop delivery system for food additives and nutraceutical components. 相似文献
110.
Konstantinos D. Patlitzianas Haris Doukas Dimitris Th. Askounis 《Renewable Energy》2007,32(10):1689-1704
The cooperation between the European Union (EU) and the Gulf Cooperation Council (GCC) should be broadened, deepened and become more interactive due to GCC states’ accession to the Kyoto protocol in 2005. Nowadays, the GCC states start putting climate change and its business opportunities on the top of their priorities’ list towards the accomplishment of the sustainable development goals. However, the level of development of sustainable energy investments (renewable energy, CO2 sequestration and rational use of energy) is low until now in the GCC. For the above reason, the assessment of appropriate investments needs to be taken into account both by the governments in order to design the appropriate framework for supporting them and the project investors to identify the commercially profitable ones. In this framework, the aim of this paper is the identification and assessment of sustainable energy investments in the framework of the EU–GCC co-operation. 相似文献