排序方式: 共有154条查询结果,搜索用时 31 毫秒
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In hyperspectral image classification problems, the discriminative efficiency of the classifier depends on the features. To classify the heterogeneous classes present in hyperspectral imagery, biologically inspired models such as log-Gabor features are useful as they exhibit joint spatial-spectral characteristics of each pixel. Log-Gabor features occupy the state-of-the-art hyperspectral research domain for extracting the features at different scales and orientations. In this proposed work, three-dimensional log-Gabor wavelets with different scales and orientations are designed to obtain the complete spatial, spectral and joint spatial-spectral characteristics of individual pixels in the hyperspectral data. Aiming to improve the accuracy, a simple fuzzy inspired algorithm is also proposed. The performance of the proposed algorithm is evaluated and is compared with other existing methods and supremacy is observed. The proposed methods are experimented on airborne visible infrared imaging sensor (AVIRIS) data of Indian Pine Site. The results witness the accuracy of 92.13% even while only 5% of the samples in each class were used for training for 3D log-Gabor features. Fuzzy inspired 3D log-Gabor features produce the accuracy of 93.11% for 5% training samples. 相似文献
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A pilot study was carried out to investigate the performance of ultrasound stiffness imaging methods namely Ultrasound Elastography Imaging (UEI) and Acoustic Radiation Force Impulse (ARFI) Imaging. Specifically their potential for characterizing different classes of solid mass lesions was analyzed using agar based tissue mimicking phantoms. Composite tissue mimicking phantom was prepared with embedded inclusions of varying stiffness from 50 kPa to 450 kPa to represent different stages of cancer. Acoustic properties such as sound speed, attenuation coefficient and acoustic impedance were characterized by pulse echo ultrasound test at 5 MHz frequency and they are ranged from (1564 ± 88 to 1671 ± 124 m/s), (0.6915 ± 0.123 to 0.8268 ± 0.755 db cm-1 MHz-1) and (1.61×106 ± 0.127 to 1.76 × 106 ± 0.045 kg m-2 s-1) respectively. The elastic property Young’s Modulus of the prepared samples was measured by conducting quasi static uni axial compression test under a strain rate of 0.5 mm/min upto 10 % strain, and the values are from 50 kPa to 450 kPa for a variation of agar concentration from 1.7% to 6.6% by weight. The composite phantoms were imaged by Siemens Acuson S2000 (Siemens, Erlangen, Germany) machine using linear array transducer 9L4 at 8 MHz frequency; strain and displacement images were collected by UEI and ARFI. Shear wave velocity 4.43 ± 0.35 m/s was also measured for high modulus contrast (18 dB) inclusion and X.XX m/s was found for all other inclusions. The images were pre processed and parameters such as Contrast Transfer Efficiency and lateral image profile were computed and reported. The results indicate that both ARFI and UEI represent the abnormalities better than conventional US B mode imaging whereas UEI enhances the underlying modulus contrast into improved strain contrast. The results are corroborated with literature and also with clinical patient images. 相似文献
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Employment of Jacobian elliptic functions for solving problems in nonlinear dynamics of microtubules 下载免费PDF全文
Slobodan Zekovi Annamalai Muniyappan Slobodan Zdravkovi Louis Kavitha 《中国物理 B》2014,23(2):20504-020504
We show how Jacobian elliptic functions (JEFs) can be used to solve ordinary differential equations (ODEs) describing the nonlinear dynamics of microtubules (MTs). We demonstrate that only one of the JEFs can be used while the remaining two do not represent the solutions of the crucial differential equation. We show that a kinkbtype soliton moves along MTs. Besides this solution, we also discuss a few more solutions that may or may not have physical meanings. Finally, we show what kind of ODE can be solved by using JEFs. 相似文献
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Channappa N. Kavitha Hemmige S. Yathirajan Manpreet Kaur Eric C. Hosten Richard Betz Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(8):805-811
The structures of two salts of flunarizine, namely 1‐bis[(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine, C26H26F2N2, are reported. In flunarizinium nicotinate {systematic name: 4‐bis[(4‐fluorophenyl)methyl]‐1‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazin‐1‐ium pyridine‐3‐carboxylate}, C26H27F2N2+·C6H4NO2−, (I), the two ionic components are linked by a short charge‐assisted N—H...O hydrogen bond. The ion pairs are linked into a three‐dimensional framework structure by three independent C—H...O hydrogen bonds, augmented by C—H...π(arene) hydrogen bonds and an aromatic π–π stacking interaction. In flunarizinediium bis(4‐toluenesulfonate) dihydrate {systematic name: 1‐[bis(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine‐1,4‐diium bis(4‐methylbenzenesulfonate) dihydrate}, C26H28F2N22+·2C7H7O3S−·2H2O, (II), one of the anions is disordered over two sites with occupancies of 0.832 (6) and 0.168 (6). The five independent components are linked into ribbons by two independent N—H...O hydrogen bonds and four independent O—H...O hydrogen bonds, and these ribbons are linked to form a three‐dimensional framework by two independent C—H...O hydrogen bonds, but C—H...π(arene) hydrogen bonds and aromatic π–π stacking interactions are absent from the structure of (II). Comparisons are made with some related structures. 相似文献
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Methylene Blue and some other thiazine dyes are titrated at room temperature visually and potentiometrically in presence of 0.005-0.1N oxalic acid. The effect of oxalic acid on the conditional potentials of the Ti(IV)/Ti(III) couple is presented. 相似文献
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Kavitha Jayachandran R. D. Bhanushali I. C. Pius S. K. Mukerjee 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):103-109
Synthetic inorganic exchangers exhibit good thermal and radiation stability. Thorium oxalate precipitate shows potential for
co-precipitation of plutonium and americium from oxalate supernatant generated during plutonium oxalate precipitation. In
the present study, efforts were made to prepare thorium oxalate precipitate to be used for column operation. Distribution
ratios were determined to optimize conditions for sorption of plutonium and americium on thorium oxalate from nitric acid
+ oxalic acid solutions with composition similar to that of oxalate supernatant. Column experiments were also performed to
evaluate the sorption capacity of thorium oxalate for plutonium and americium from the same medium. The result showed that,
thorium oxalate prepared in 1.75M HNO3 at 70 °C is suitable for column operations. These studies showed that plutonium and americium could be simultaneously removed
from aqueous solutions with composition similar to plutonium oxalate waste using glass column packed with thorium oxalate
and these nuclides could be recovered by eluting with 3M HNO3. 相似文献
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Chaudhary PM Chavan SR Kavitha M Maybhate SP Deshpande SR Likhite AP Rajamohanan PR 《Magnetic resonance in chemistry : MRC》2008,46(12):1168-1174
Propargylation of 3-substituted-1,2,4-triazole-5-thiols, which predominantly exist as their thione tautomers, was carried out with the view to synthesize different heterocycles and study their biological activity. Three different products namely, a mono S-propargyl and two S,N-dipropargyl regioisomers, arising from N1/N2 substitution, were isolated and characterized. Unambiguous structural elucidation of the regioisomers of S,N-dipropargyl derivatives was achieved by means of (13)C-(1)H HMBC technique. The proportion of the regioisomers was found to vary with the substituent on the 1,2,4-triazole thiols. No product corresponding to N4 substitution was isolated from any of the reactions carried out. 相似文献
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Chang SY Kavitha J Hung JY Chi Y Cheng YM Li EY Chou PT Lee GH Carty AJ 《Inorganic chemistry》2007,46(17):7064-7074
New Pt(II) dichloride complexes [Pt(1-iqdzH)Cl2] (2a) and [Pt(3-iqdzH)Cl2] (2b), in which idqzH = 1- or 3-isoquinolinyl indazole, were prepared by treatment of the corresponding indazoles with K2PtCl4 in aqueous HCl solution. Despite their nonemissive nature, these complexes could react with excess indazole, sodium picolinate, and 3-trifluoromethyl-5-(2-pyridyl) pyrazole [(fppz)H] to afford the respective a and b series of luminescent complexes [Pt(1-iqdz)(L/\X)] and [Pt(3-iqdz)(L/\X)], where L/\X = 1-iqdz (1a), 3-iqdz (1b), pic (3a, 3b), and fppz (4a, 4b). Single-crystal X-ray diffraction studies of 1b, 2a, and 3b revealed a planar molecular geometry without notable intermolecular Pt...Pt contact in the solid crystal, a result of the steric repulsion imposed by the bulky indazole fragments. For coordination complexes 1, 3, and 4, photoluminescence in degassed CH2Cl2 revealed high quantum efficiency and short radiative lifetimes in the range of several microseconds. As supported by the spectral feature, the associated radiation lifetimes, and a computational approach based on time-dependent density function theory (TD-DFT), the origin of the emission is attributed to a mixed 3MLCT/3pipi transition. The TD-DFT approach further confirmed that, except for the series 1 complexes, the HOMO of 3-iqdz complexes 3b and 4b is much less located at the central Pt(II) atom than the HOMO orbitals of the respective 1-iqdz complexes 3a and 4a, leading to a smaller degree of MLCT contribution. Consequently, there are a blue-shifted emission signal and an inferior emission quantum yield for the 3-iqdz derivatives. OLED devices with a multilayer configuration of ITO/NPB/CBP:3a/BCP/Alq3/LiF/Al were fabricated using a CBP layer doped with various concentrations of 3a, ranging from 6% to 100%, within the emitting layer. The best device performance was realized using a 6% doping concentration, for which the external quantum yield of 4.93%, luminous efficiency of 12.19 cd/A, and power efficiency of 6.12 lm W-1 were observed at 20 mA/cm2, while a maximum luminescence as high as 20296 cd/m2 was also realized at 16 V, showing good prospect for the fabrication of Pt(II) based OLEDs. 相似文献