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排序方式: 共有120条查询结果,搜索用时 312 毫秒
31.
V. Sankaranarayanan Arun D. Mahindrakar 《Communications in Nonlinear Science & Numerical Simulation》2009,14(5):2319-2327
We present a switched control algorithm to stabilize a car-like mobile robot which possesses velocity level nonholonomic constraint. The control approach rests on splitting the system into several second-order subsystems and then stabilizing the system sequentially using finite-time controllers, finally resulting in the mobile robot being moved from one point to another point. State dependent switching control is employed in which the controllers switches on a thin surface in the state-space. Robustness analysis is presented by redefining the switching signal using relaxed switching surface. Both, non-robust and robust controllers are validated through numerical simulation. 相似文献
32.
R. K. Sankaranarayanan S. Siva A. Antony Muthu Prabhu N. Rajendiran 《Journal of inclusion phenomena and macrocyclic chemistry》2010,67(3-4):461-470
Effect of β-cyclodextrin (β-CD) on the absorption and fluorescence spectra of 3,4,5-trihydroxybenzoic acid (THB) have been studied buffer solutions of different pHs (pH ~1, pH ~7 and pH ~10). The study reveals that in all the above pHs THB forms 1:1 inclusion complex. The hydroxyl groups are present in the interior part of the β-CD cavity and carboxyl group is present in the hydrophilic part of the β-CD cavity. Dual luminescence is observed at pH ~1 and pH ~7 solutions which shows that intramolecular charge transfer present at these pH. The broad spectral maximum at pH ~10 indicates that intramolecular proton transfer is present in THB. 相似文献
33.
A. Sankaranarayanan 《Rendiconti del Circolo Matematico di Palermo》1999,48(2):243-256
An even integern≥6 is called a Goldbach number if it is the sum of two odd primes. The Goldbach conjecture says that every even numbern≤6 is a Goldbach number. In this paper, we study the mean-square upper bound of the error term related to the Goldbach problem,
in polynomial values over short intervals, uniformly with respect to the height of a polynomial of fixed degree. 相似文献
34.
35.
Development of a new lectron-recoil ion/photon coincidence setup for investigating some of the electron induced collision processes, such as electron bremsstrahlung, electron backscattering,
innershell excitation and multiple ionization of target atoms/molecules in bombardment of electrons having energies from 2.0
keV to 30.0 keV with solid and gaseous targets is described. The new features include the use of a compact multipurpose scattering
chamber, a time-of-flight spectrometer for detection of multiply charged target ions, a 45°-parallel plate electrostatic analyzer
for measuring energy and angle of the ejected electrons, a room temperature high resolution Si-PIN photo diode X-ray detector
for counting the collisionally induced photons, a coincidence data acquisition system consisting of a 200 MHz Pentium based
8K-multichannel analyzer and a standard network of a fast/slow coincidence electronics. In particular, the details of design,
fabrication and assembly of indigenous components employed in the setup are presented. Selected experiments planned with the
setup are mentioned and briefly discussed. A report on performance, optimization, efficiency, time resolution etc. of the
time-of-flight (TOF) spectrometer and that of the 45°-parallel plate electrostatic analyzer (PPEA) is presented. Test spectra
of electron-recoil ion coincidences, energy distribution of ejected electrons and characteristic plus non-characteristic X-ray
spectrum are illustrated to exhibit the satisfactory performance of the developed setup. 相似文献
36.
K. Kumar K. Ramamoorthy P. M. Koinkar R. Chandramohan K. Sankaranarayanan 《Journal of nanoparticle research》2007,9(2):331-335
A novel route to the growth of thin films of ZnAl2O4 in nano-scale order was developed and nano-thin films of ZnAl2O4 are grown. The variation of grain size with solution concentration is reported. The thin film was deposited by modified liquid-phase
deposition (LPD) technique using a novel acid based chemical reaction for the first time to ternary system. This modified
LPD is based on a novel reaction that favours the formation of nanostructures during the treatment of a precursor (here ZnO)
and a metal foil (Al) in diluted HF acid. The acid serves both as a solvent and catalyst. Usually, in wet process synthesis
of binary systems, the metal foil will act as F− ion scavenger. In this method, formation of a ternary compound as well as growth of thin film nanostructures of that compound
was achieved by the same chemical reaction at room temperature. The role of acid concentration in the nanostructure formation
is discussed. The relationship between HF concentration and grain size were also graphically enumerated. Structural, compositional
and surface morphological properties of thin films were studied using Philips, Xpert-MPD: X-ray diffractometer and Philips,
ESEM-TMP + EDAX, Nanoscope-III: AFM. The technique is a novel, simple and low cost route for the growth of nano-thin films
of ternary oxide material. 相似文献
37.
38.
Hariprakash Sharma B Sethi P Banerjee Ranjana Goswami RK Bhandari Jahan Singh 《Pramana》2001,57(1):171-174
Recent experimental data on 125I has revealed several interesting structural features. These include the observation of a three quasiparticle band, prolate
and oblate deformed bands, signature inversion in the yrast positive-parity band and identification of the unfavoured πh
11/2 band showing very large signature splitting. In the present work, particle-rotor-model calculations have been performed for
the πh
11/2 band, using an axially symmetric deformed Nilsson potential. The calculations reproduce the experimental results well and
predict a moderate prolate quadrupole deformation of about 0.2 for the band. 相似文献
39.
K. Kumar K. Ramamoorthy R. Chandramohan K. Sankaranarayanan 《Crystal Research and Technology》2006,41(3):217-220
ZnAl2O4 is a well‐known wide band gap compound semiconductor (Eg=3.8eV), ceramic, opto‐mechanical, anti‐thermal coating in aero‐space vehicles and UV optoelectronic devices. A novel method for the growth of single crystals of a ternary oxide material was developed as a fruit of a long term work. Material to be grown as metal incorporated single crystal was taken as precursor and put into a bath containing acid as reaction speed up reagent (catalyst) as well as solvent with a metal foil as cation scavenger. Using this method, ZnAl2O4 crystals having hexagonal facets are prepared from a single optimized bath. Structural and compositional properties of crystals were studied using Philips, Xpert ‐ MPD: X‐ray diffractometer and Philips, ESEM‐TMP + EDAX. Thus technique was found to be a new low cost and advantageous method for growth of single crystals of ternary oxide a material. We hope that these data be helpful either as a scientific or technical basis in material processing. Dedicated to Prof. P. Ramasamy © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim 相似文献
40.
Bestenur YALIN Doan AKCAN brahim Erturul YALIN Mehmet Can ALPHAN Kenan ENTÜRK brahim lker
ZYT Lütfi ARDA 《Turkish Journal of Chemistry》2020,44(4):1177
The objective of this study is to synthesize ZnO and Mg doped ZnO (Zn1−xMgxO) nanoparticles via the sol-gel method, and characterize their structures and to investigate their biological properties such as antibacterial activity and hemolytic potential.Nanoparticles (NPs) were synthesized by the sol-gel method using zinc acetate dihydrate (Zn(CH3COO)2.2H2O) and magnesium acetate tetrahydrate (Mg(CH3COO)2.4H2O) as precursors. Methanol and monoethanolamine were used as solvent and sol stabilizer, respectively. Structural and morphological characterizations of Zn1−xMgxO nanoparticles were studied by using XRD and SEM-EDX, respectively. Photocatalytic activities of ZnO and selected Mg-doped ZnO (Zn1−xMgxO) nanoparticles were investigated by degradation of methylene blue (MeB). Results indicated that Mg doping (both 10% and 30%) to the ZnO nanoparticles enhanced the photocatalytic activity and a little amount of Zn0.90 Mg0.10 O photocatalyst (1.0 mg/mL) degraded MeB with 99% efficiency after 24 h of irradiation under ambient visible light. Antibacterial activity of nanoparticles versus Escherichia coli ( E. coli ) was determined by the standard plate count method. Hemolytic activities of the NPs were studied by hemolysis tests using human erythrocytes. XRD data proved that the average particle size of nanoparticles was around 30 nm. Moreover, the XRD results indicatedthat the patterns of Mg doped ZnO nanoparticles related to ZnO hexagonal wurtzite structure had no secondary phase for x ≤ 0.2 concentration. For 0 ≤ x ≤ 0.02, NPs showed a concentration dependent antibacterial activity against E. coli . While Zn0.90Mg0.10 O totally inhibited the growth of E. coli , upper and lower dopant concentrations did not show antibacterial activity. 相似文献