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1.
Venkidusamy Vasanthi Muniasamy Kottaisamy Veerabahu Ramakrishnan 《Journal of Materials Science: Materials in Electronics》2018,29(23):19724-19731
Optical properties of Zn doped Y2O3 microsheets prepared by sol–gel combustion method have been investigated and their application in phosphor converted white LED has been examined. The formation of single phase, well crystalline cubic Y2O3 is confirmed from powder XRD results. Effective substitution of Zn in Y2O3 crystal lattice is inferred from shifting of diffraction peaks. SEM images have showed that undoped as well as Zn doped Y2O3 formed as microsheets. Doping of Zn enhanced the growth of the sheets and its length increased from 1.5 to 19 µm. Development of structural disorder in Y2O3 crystal structure after Zn doping and confirmation of the conserved cubic structure of Zn doped Y2O3 without any secondary phase have been revealed from micro-Raman spectra. The optical band gap of Y2O3 has been altered after Zn doping and it is found to be decreased from 5.6 to 5.22 eV as increasing Zn concentration. Both undoped and Zn doped Y2O3 showed a broad visible emission from blue to green region due to various defects and impurities present in it. Broad PL excitation spectrum inferred the possibility to attain the visible emission under the excitation of light with wide range of wavelength from near UV to blue region. Excitation of pure Y2O3 under near UV (375 nm) LED chip lead to the emission of yellow light whereas Zn doped Y2O3 emitted warm white light with color coordinate of (0.42, 0.35), colour rendering index of 77.6 and correlated color temperature (CCT) of 2840 K. Hence, Zn doped Y2O3 discussed in the present work can be a better replacement for various rare earth doped phosphors in the application of phosphor converted WLED (pc-WLED). 相似文献
2.
Dinabandhu Patra Ramakrishnan Ganesan Balaji Gopalan 《International Journal of Hydrogen Energy》2021,46(50):25486-25499
We report the catalytic enhancement of hydrogen generation by 1) in situ Fe (0) formed and 2) nitroarenes substrates during Fe3O4@Pd core-shell nanoparticles catalyzed tandem reaction. The active hydrogen species are generated in Pd shell, which either combine to form H2 gas or take part in relatively faster nitroarene reduction reaction. The rate of hydrogen generation from ammonia borane is dependent on the nitroarene substrate and is higher when 4-nitrophenol is used. This is due to the difference in ammonia borane adsorption on the surface of the catalyst. During recyclability, the H2 generation rate of 2 wt% Pd loaded samples is higher than other compositions. Such an enhancement has been attributed to the formation of Fe (0) via γ-FeOOH mediated by Pd species, presumably through Pd(OH)2. The electronic connection between Fe and Pd interface is thus shown to play an important role in the catalytic enhancement of the tandem reaction. 相似文献
3.
In deregulated power system scenario coupled with smart grid technology, for networked load frequency control (LFC), an open communication structure, owing to low cost and flexibility, is preferred over dedicated networks in the feedback control loop for transmitting/receiving the data between the geographically displaced power system and the control center. In such a control scheme, closing the feedback loop through an open communication channel, in turn, introduces two additive time-varying delays of dissimilar characteristics in the feedback path. These delays degrade the performance of the closed-loop system, and exert a destabilizing effect on the overall system. In this paper, using Lyapunov-Krasovskii functional approach, a less conservative stability criterion is presented to ascertain delay-dependent stability of such network-controlled LFC systems with two additive time-varying delays in the feedback path in the presence of uncertain load disturbance conditions. Unlike the existing results, which are derived by combining these two delays into one, the proposed result considers the two delays as separate entities thereby imparting more generalization into the stability analysis. The effect of unknown exogenous load disturbance is incorporated by mathematically modeling them as a bounded non-linear time-varying function of current and delayed state vectors. 相似文献
4.
A thiol‐ene clickable hyperbranched polyester via a simple single‐step melt trans‐esterification process 下载免费PDF全文
Self‐condensation of AB2 type monomers (containing one A‐type and two B‐type functional groups) generates hyperbranched (HB) polymers that carry numerous B ‐type end‐groups at their molecular periphery; thus, development of synthetic methods that directly provide quantitatively transformable peripheral B groups would be of immense value as this would provide easy access to multiply functionalized HB systems. A readily accessible AB2 monomer, namely diallyl, 5‐(4‐hydroxybutoxy)isophthalate was synthesized, which on polymerization under standard melt‐transesterfication conditions yielded a peripherally clickable HB polyester in a single step; the allyl groups were quantitatively reacted with a variety of thiols using the facile photoinitiated “thiol‐ene” reaction to generate a wide range of derivatives, with varying solubility and thermal properties. Furthermore, it is shown that the peripheral allyl double bonds can also be readily epoxidized using meta‐chloroperoxybenzoic acid to yield interesting HB systems, which could potentially serve as a multifunctional cross‐linking agent in epoxy formulations. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40248. 相似文献
5.
Silicon - The performance analysis of Ge-Si-VTFETs for analog/RF applications has been studied in this article under various gate dielectric materials. In the proposed device, Ge/Si materials were... 相似文献
6.
Salleh Emee Marina Zuhailawati Hussain Ramakrishnan Sivakumar Dhindaw Brij Kumar 《Metallurgical and Materials Transactions A》2017,48(5):2519-2528
Metallurgical and Materials Transactions A - Magnesium (Mg) and its alloys have shown potential for use in the biomedical industry due to their excellent biological performance and biodegradability... 相似文献
7.
Manali Kamath Mukund Arunraj Rex Ramakrishnan Gautham Subramaniam Ramya Mohandass 《Food science and biotechnology》2019,28(2):609-614
Food Science and Biotechnology - Spirulina has emerged as the next-generation dietary supplement owing to its health benefits. Despite the advantages, there have been reports of contamination by... 相似文献
8.
Wireless Personal Communications - A VANET is an excellent instance of a wireless sensor network. The mobile vehicles are the nodes and communication happens between the vehicular nodes. This... 相似文献
9.
Hendawi Abdeltawab Gupta Jayant Liu Jiayi Teredesai Ankur Ramakrishnan Naveen Shah Mohak El-Sappagh Shaker Kwak Kyung-Sup Ali Mohamed 《The Journal of supercomputing》2019,75(12):8207-8230
The Journal of Supercomputing - In the current era of the Internet of Things (IoT), massive number of sensors are used in our daily lives. Sensors are everywhere around us. They exist in our homes,... 相似文献
10.
S. Licht O. Khaselev P. A. Ramakrishnan D. Faiman E. A. Katz A. Shames 《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(1):125-136
Abstract Fullerene solar cells are demonstrated. Illuminated, C60 drives oxidation of redox couples in solution. a photoelectrochemical solid/liquid, rather than a solid state, junction, improves photocurrent, and a C60 single crystal, and not polycrystalline film, decreases dark current, and thereby light driven charge transfer dominates. 相似文献