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211.
212.
Asma Tufail Shah Adnan Mujahid Muhammad Umar Farooq Waqar Ahmad Baoshan Li Muhammad Irfan Muhammad Abdul Qadir 《Journal of Sol-Gel Science and Technology》2012,63(1):194-199
The nanoparticles of monovacant lacunary keggin-type polyoxometalate (C19H42N)4H3(PW11O39) has been successfully synthesized by Micelle Directed Method using hexadecyltrimthyl ammonium bromide (CTAB) as a template. Non-ionic copolymer Pluronic F127 was used as a capping agent that helps in formation of nanoparticles by preventing the aggregation during the coating of H3(PW11O39)4- onto the counter ion (C19H42N)+. The synthesized material was characterized by Scanning electron microscope (SEM), TGA, DSC and FT-IR techniques. SEM images indicated that (C19H42N)4H3(PW11O39) nanoparticles possess spherical structure. FTIR results revealed that the structural integrity of monovacant lacunary keggin-type polyoxometalates (POM) was not affected when reducing the size. TGA–DSC results showed that the material was thermally stable (with 37 % weight loss) and POM encapsulates CTAB. The efficiency of synthesized material was checked by applying it as a catalyst for the oxidation of toxic mordant yellow dye i.e., potentially hazardous and non-biodegradable azo dye. The (C19H42N)4H3(PW11O39) nanoparticles gave 96 % dye degradation in 60 min at 60 °C temperature. Moreover, on recycling POM nanoparticles demonstrate 92 % oxidative degradation of mordant yellow dye. 相似文献
213.
Ahmad Umar M.M. Rahman Mohammad Vaseem Yoon-Bong Hahn 《Electrochemistry communications》2009,11(1):118-121
A high-sensitive cholesterol amperometric biosensor based on the immobilization of cholesterol oxidase (ChOx) onto the ZnO nanoparticles has been fabricated which shows a very high and reproducible sensitivity of 23.7 μA mM?1 cm?2, detection limit (based on S/N ratio) 0.37 ± 0.02 nM, response time less than 5 s, linear range from 1.0 to 500.0 nM and correlation coefficient of R = 0.9975. A relatively low value of enzyme’s kinetic parameter (Michaelis–Menten constant) ~4.7 mM has been obtained which indicates the enhanced enzymatic affinity of ChOx to Cholesterol. To the best of our knowledge, this is the first report in which such a very high-sensitivity and low detection limit has been achieved for the cholesterol biosensor by using ZnO nanostructures modified electrodes. 相似文献
214.
We establish locality estimates, known as Lieb–Robinson bounds, for the Toda lattice. In contrast to harmonic models, the
Lieb–Robinson velocity for these systems do depend on the initial condition. Our results also apply to the entire Toda as
well as the Kac-van Moerbeke hierarchy. Under suitable assumptions, our methods also yield a finite velocity for certain perturbations
of these systems. 相似文献
215.
Image encryption based on elliptic curves (ECs) is emerging as a new trend in cryptography because it provides high security with a relatively smaller key size when compared with well-known cryptosystems. Recently, it has been shown that the cryptosystems based on ECs over finite rings may provide better security because they require the computational cost for solving the factorization problem and the discrete logarithm problem. Motivated by this fact, we proposed a novel image encryption scheme based on ECs over finite rings. There are three main steps in our scheme, where, in the first step, we mask the plain image using points of an EC over a finite ring. In step two, we create diffusion in the masked image with a mapping from the EC over the finite ring to the EC over the finite field. To create high confusion in the plain text, we generated a substitution box (S-box) based on the ordered EC, which is then used to permute the pixels of the diffused image to obtain a cipher image. With computational experiments, we showed that the proposed cryptosystem has higher security against linear, differential, and statistical attacks than the existing cryptosystems. Furthermore, the average encryption time for color images is lower than other existing schemes. 相似文献
216.
Salman Khalil Umar Muhammad Modibbo Ather Aziz Rain Irfan Ali 《Journal of Nonlinear Modeling and Analysis》2023,5(2):311-324
The methods of multiple criteria decision-making (MCDM) are increasingly becoming the most desired tools for making daily decisions in various fields of human endeavors. Staff employment in any sector requires a thorough evaluation of the applicant before selection to ensure effective and efficient service delivery. Besides, healthcare is one of the most complicated organizations dealing with human lives. This paper has developed a staff selection model considering a fuzzy environment by using the technique for order preference similar to the ideal solution (TOPSIS) method. For the delivery and promotion of quality healthcare systems, medical staff selection is crucial to the system. Therefore, the study evaluates medical staff by using the expert''s linguistic judgement under the criteria of skill, experience and ability to respond to a problem. The expert''s vagueness in judgments has been represented by using fuzzy triangular numbers. The study determines the closeness coefficient, the measures of separation and the ideal solutions of the TOPSIS method. The most appropriate medical staff are ranked and selected based on the available criteria. The Fuzzy-TOPSIS method is simple and can help other organizations achieve proper ranking, evaluation and selection of qualified candidates, as it takes imprecise information into account. 相似文献