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721.
Hofmann O Wang X Cornwell A Beecher S Raja A Bradley DD Demello AJ Demello JC 《Lab on a chip》2006,6(8):981-987
We report the fabrication of high quality monolithically integrated optical long-pass filters, for use in disposable diagnostic microchips. The filters were prepared by incorporating dye molecules directly into the microfluidic chip substrate, thereby providing a fully integrated solution that removes the usual need for discrete optical filters. In brief, lysochrome dyes were added to a poly(dimethylsiloxane) (PDMS) monomer prior to moulding of the microchip from a structured SU-8 master. Optimum results were obtained using 1 mm layers of PDMS doped with 1200 microg mL(-1) Sudan II, which resulted in less than 0.01% transmittance below 500 nm (OD 4), >80% above 570 nm, and negligible autofluorescence. These spectral characteristics compare favourably with commercially available Schott-glass long-pass filters, indicating that high quality optical filters can be straightforwardly integrated into the form of PDMS microfluidic chips. The filters were found to be robust in use, showing only slight degradation after extended illumination and negligible dye leaching after prolonged exposure to aqueous solutions. The provision of low cost high quality integrated filters represents a key step towards the development of high-sensitivity disposable microfluidic devices for point-of-care diagnostics. 相似文献
722.
T. Raja Sekhar V.D. Sharma 《Communications in Nonlinear Science & Numerical Simulation》2012,17(2):630-636
In this paper, we obtain exact solutions to the nonlinear system of partial differential equations (PDEs), describing the one dimensional modified shallow water equations, using invariance group properties of the governing system. Lie group of point symmetries with commuting infinitesimal operators, are presented. The symmetry generators are used for constructing similarity variables which lead the governing system of PDEs to system of ordinary differential equations (ODEs); in some cases, it is possible to solve these equations exactly. A particular solution to the governing system, which exhibits space-time dependence, is used to study the evolutionary behavior of weak discontinuities. 相似文献
723.
D.M. Raj Kumar N.V. Rama RaoM. Manivel Raja D.V. Sridhara RaoM. Srinivas S. Esakki MuthuS. Arumugam K.G. Suresh 《Journal of magnetism and magnetic materials》2012,324(1):26-32
Melt spun Ni50−xMn37+xIn13 (2≤x≤5) ribbons were investigated for the structure, microstructure, magneto-structural transitions and inverse magnetocaloric effect (IMCE) associated with the first-order martensitic phase transition. The influence of excess Mn in Ni site (or Ni/Mn content) on the martensite transition and the associated magnetic and magnetocaloric properties are discussed. It was found that with the increase in Mn content, the martensitic transition shifted from 325 to 240 K as x is varied from 2 to 4, and the austenite phase was stabilized at room temperature. The x=5 ribbon did not show the martensitic transition. For the x=3 ribbon, the structural and magnetic transitions are close together unlike in the x=4 ribbon in which they are far (∼60 K) apart. The zero field cooled and field cooled curves support the presence of exchange bias blocking temperature due to antiferromagnetic interactions in the ribbons. A large change in the magnetization between the martensite and austenite phases was observed for a small variation in the Ni/Mn content, which resulted in large IMCE. A large positive magnetic entropy change (ΔSM) of 32 J/kg K at room temperature (∼ 300 K) for a field change of 5 T with a net refrigeration capacity of 64 J/kg was obtained in the Ni47Mn40In13 ribbon. 相似文献
724.
S.S. Kalyan Kamal P.K. Sahoo L. Durai P. Ghosal M. Manivel Raja S. Ram 《Journal of magnetism and magnetic materials》2012
Small crystallites of a metastable phase Co0.5Pt0.5 are precipitated by heating a rheological liquid precursor of cobalt–hydrazine complex and platinum chloride H2PtCl6·xH2O in polymer molecules of poly(vinylpyrrolidone) (PVP) in ethylene glycol. The hydrazine co-reduces nascent atoms from the Co2+ and Pt4+ that recombine and grow as Co0.5Pt0.5. The PVP molecules cap a growing Co0.5Pt0.5 as it achieves a critical size so that it stops growing further in given conditions. X-ray diffraction pattern of a recovered powder reveals a crystalline Co0.5Pt0.5 phase (average crystallite size D∼8 nm) of a well-known Fm3m-fcc crystal structure with the lattice parameter a=0.3916 nm (density ρ=14.09 g/cm3). A more ordered L10 phase (ρ=15.91 g/cm3) transforms (D≥25 nm) upon annealing the powder at temperature lesser than 700 °C (in vacuum). At room temperature, the virgin crystallites bear only a small saturation magnetization Ms=5.54 emu/g (D=8 nm) of a soft magnet and it hardly grows on bigger sizes (D≤31 nm) in a canted ferromagnetic structure. A rectangular hysteresis loop is markedly expanded on an optimally annealed L10 phase at 800 °C for 60 min, showing a surface modified coercivity Hc=7.781 kOe with remnant ratio Mr/Ms=0.5564, and Ms=39.75 emu/g. Crystallites self-assembled in an acicular shape tailor large Hc from ideal single domains and high magnetocrystalline anisotropy of a hard magnet L10 phase. 相似文献
725.
Srinivasan K Senthilkumar DV Raja Mohamed I Murali K Lakshmanan M Kurths J 《Chaos (Woodbury, N.Y.)》2012,22(2):023124
We construct a new RC phase shift network based Chua's circuit, which exhibits a period-doubling bifurcation route to chaos. Using coupled versions of such a phase-shift network based Chua's oscillators, we describe a new method for achieving complete synchronization (CS), approximate lag synchronization (LS), and approximate anticipating synchronization (AS) without delay or parameter mismatch. Employing the Pecora and Carroll approach, chaos synchronization is achieved in coupled chaotic oscillators, where the drive system variables control the response system. As a result, AS or LS or CS is demonstrated without using a variable delay line both experimentally and numerically. 相似文献
726.
R. Shweikani M.S. Al-Masri M. Hushari G. Raja M. Aissa R. Al-Hent 《Radiation measurements》2012,47(7):557-560
Natural radiation background has been determined for the Ancient City of Palmyra and its surrounding areas. Car-borne gamma spectrometry, indoor radon gas concentration and natural radionuclides levels in environmental samples (soil, water and plants) have been determined. Two types of dwelling were involved in this study, one with cancer cases, and the others without. The results showed that indoor radon gas concentrations and radiation exposure rates are within reported mean background levels in Syria (45 Bq m?3 and less than 0.1 μSv h?1, respectively); no differences were noticed between the dwelling groups. In addition, the results did not indicate any relation between recorded cancers and measured natural radioactivity. 相似文献
727.
Motivated with the continued demand for developing quality material showing better response for the efficient removal of organo‐amphiphilic toxicants, we have demonstrated the growth of three‐dimensional polymer organic framework—a covalent crosslinked polymer C2B derived via photon triggered thiol‐alkene click reaction. Instrumentation techniques such as nuclear magnetic resonance, thermogravimetric analysis, and fourier transform infrared spectroscopy were used for the characterization. FESEM and Cryo‐SEM analysis were done to analyze the morphology of the resin. The adsorption and release experiments were done with ultraviolet‐visible spectroscopic technique. The polymer C2B derived from polyolefin and tetrathiol via thiol‐alkene photoclick reaction showed efficiency toward adsorption of organo‐amphiphilic contaminants such as dioxane, dimethylformamide, fluorescein, and rhodamine B (RH). Even the material selectively showed the efficient release of toxicant—RH. Moreover, it can be reused over cycles. This makes the polymer C2B as potential candidate to be commercially viable for textile industries. 相似文献
728.
Meccanica - We present an analytical study of the effective viscosity of concentrated suspension of porous spherical particles with a rigid core, under the creeping flow conditions. It is assumed... 相似文献
729.
Suman Kuila Anaranya Ghorai Dr. Pralok K. Samanta Dr. Raja B. K. Siram Prof. Dr. Swapan K. Pati Prof. Dr. K. S. Narayan Prof. Dr. Subi J. George 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(70):16007-16011
Unprecedented ambient triplet-mediated emission in core-substituted naphthalene diimide (cNDI) derivatives is unveiled via delayed fluorescence and room temperature phosphorescence. Carbazole core-substituted cNDIs, with a donor–acceptor design, showed deep-red triplet emission in solution processable films with high quantum yield. This study, with detailed theoretical calculations and time-resolved emission experiments, enables new design insights into the triplet harvesting of cNDIs; an important family of molecules which has been, otherwise, extensively been investigated for its n-type electronic character and tunable singlet fluorescence. 相似文献
730.