排序方式: 共有72条查询结果,搜索用时 15 毫秒
61.
S. K. Mehta Savita Chaudhary Sanjay Kumar Sukhjinder Singh 《Journal of nanoparticle research》2010,12(5):1697-1709
This article demonstrates the influence of various surfactants of different polarities—anionic, sodium dodecyl sulfate, cationic,
hexadecyltrimethylammonium bromide and non-ionic, and polyoxyethylene iso-octyl phenyl ether (TX-100)—on the formation of
CdSe nanoparticles in aqueous solutions. The surfactant-stabilizing effect has been monitored using transmission electron
microscopy. Spectral properties of CdSe nanoparticles have been investigated; the structure of the long-wave edge of the fundamental
absorption band of CdSe nanoparticles has been analyzed. It has been shown that the variation of the synthesizing conditions
(stabilizer’s nature and concentration, CdSe concentration, etc.) allows the tailoring of the CdSe nanoparticle size in the
range of 8–17 nm. Lifshitz–Slyrzov–Wagner kinetic analysis has also been performed using the size variation according to ripening
temperature and time period. The differences in the stabilization ability of tested substances are discussed with respect
to their structure and possible mechanism of the surface interaction with the nanoparticles. The flexible surface chemistry
of the CdSe-micelles causes them to be water soluble and allows their further conjugation with protein molecules through electrostatic
attraction. The interaction between functionalized CdSe nanoparticles with protein molecules have been investigated using
fluorescence spectroscopy. 相似文献
62.
Savita Bhatnagar 《Proceedings Mathematical Sciences》2005,115(4):383-389
The aim of this paper is to study the algebraAC
p
of absolutely continuous functionsf on [0,1] satisfying f(0) = 0,f ’ ∈ Lp[0, 1] and the multipliers ofAC
p
. 相似文献
63.
Savita Kumari Aswini K. Mishra Dipak K. Chattopadhyay K. V. S. N. Raju 《Journal of polymer science. Part A, Polymer chemistry》2007,45(13):2673-2688
Polyurethane (PU) coatings are widely used for variety of high‐performance applications in today's coating technology. The emerging hyperbranched polymers having three‐dimensional morphology have opened a new avenue to tailor the architecture of PU coatings. The methodology followed here is based on preparation of PU coatings from hyperbranched polyester. Initially, different hyperbranched polyester polyols (HPs) were synthesized by varying the hydroxyl‐terminated precursors that is, pentaerythritol, trimethylol propane or glycerol and keeping the diacid that is, adipic acid quantity constant at various mole ratios of 1:0.6, 1:0.8, 1:0.9, and 1:1, respectively. The obtained HPs were characterized by nuclear magnetic resonance (NMR) spectroscopy, matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF)‐mass spectrometry, and Fourier transform‐infrared (FTIR) spectroscopy. The degree of branching and the quantity of different structural units present in the various HPs were calculated by integrating the quaternary carbon and carbonyl zone in 13C NMR spectroscopy. The extent of condensation in different HPs was also calculated from 1H NMR spectra. Later on, NCO‐terminated PU prepolymers (NCO‐PU) were synthesized by reacting HPs with isophorone diisocyanate (IPDI) at NCO/OH ratio of 1.6:1. In the third step, the excess NCO content in the NCO‐capped PU prepolymers were reacted with atmospheric moisture and hyperbranched polyurethane (HPU) coatings were formed. The coating films were analyzed by FTIR and dynamic mechanical thermal analysis instruments. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2673–2688, 2007 相似文献
64.
In this work, we report the size tunable synthesis of selenium (Se) nanoparticles with an average particle size ~16 nm by
using hydrazine hydrate as the reducing agent. The solution of selenium dioxide was taken as the precursor and hexadecyltrimethylammonium
bromide (CTAB) a cationic surfactant, which helps in providing sufficient stabilization to the Se nanoparticles. The synthesized
Se nanoparticles were characterized by the UV–vis, X-ray diffraction (XRD), and transmission electron microscopic techniques,
which demonstrated high stability of Se nanoparticles in aqueous media. The particle sizes estimated from the band gap values
using effective mass approximation (EMA) agreed fairly well with those calculated from the XRD measurements. The concentration
effects of Se and CTAB on the particle size have also been examined. The capping ability of the CTAB has been quantitatively
evaluated from FTIR studies. 相似文献
65.
A. K. Narula S. K. Goyal Savita Saini R. P. Chauhan S. K. Chakarvarti 《Indian Journal of Physics》2009,83(8):1171-1175
The diffusion of radon in dwellings is a process determined by the radon concentration gradient across the building material
structure between the radon source and the surrounding air, and can be a significant contributor to indoor radon inflow. Radon
can originate from the deeply buried deposit beneath homes and can migrate to the surface of earth. Radon emanates to the
surfaces mainly by diffusion processes from the point of origin following α-decay of 226Ra in underground soil and building materials used, in the construction of floors, walls, and ceilings. In the present study
radon diffusion through some building materials viz. coarse sand and stone dust of different grain size has been carried out using LR-115 type II solid-state nuclear track detectors
(SSNTDs). The radon diffusion coefficients and diffusion lengths through these building construction materials have been calculated.
The effect of grain size on radon diffusion through these building materials shows the decrease in radon diffusion with decrease
in grain size. 相似文献
66.
Jain Bharti Kulkarni Savita Banerjee Sharmila Rajan M. G. Ramakrishna 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(1):99-104
We report a microarray immunoassay for thyrotropin in serum using an anti-thyrotropin monoclonal ‘antibody-chip’ fabricated on polycarbonate track-etched membranes as a solid-support. The thyrotropin microarray immunoassay is an immunoradiometric assay using 125I tracer and requires very small volumes of sample and reagents. The microarray immunoassay had the required minimum detection level, intra- and inter-assay CV and working range to be clinically useful. It correlated very significantly with commercial immunoradiometric assays for thyrotropin. We developed this microarray immunoassay for thyrotropin since it is often used as the first line test for thyroid function.
相似文献67.
Interactive fuzzy programming approach to Bi-level quadratic fractional programming problems 总被引:1,自引:0,他引:1
In this paper we propose an interactive fuzzy programming method for obtaining a satisfactory solution to a “bi-level quadratic
fractional programming problem” with two decision makers (DMs) interacting with their optimal solutions. After determining
the fuzzy goals of the DMs at both levels, a satisfactory solution is efficiently derived by updating the satisfactory level
of the DM at the upper level with consideration of overall satisfactory balance between both levels. Optimal solutions to
the formulated programming problems are obtained by combined use of some of the proper methods. Theoretical results are illustrated
with the help of a numerical example. 相似文献
68.
Savita Kaulgud S. M. Chaudhari S. V. Ghaisas A. P. B. Sinha Y. V. Bhandarkar S. B. Ogale V. G. Bhide 《Hyperfine Interactions》1987,35(1-4):923-926
A three sweep potentiokinetic technique was employed to study the electrochemical corrosion behaviour of Fe-50 at % Ni in .1N H2SO4 solution. The as received foil did not show any passivation but it was observed in case of Fe?Ni samples implanted with N2 + ions at an energy of 100keV. Also it was seen that the primary passivation potential Epp and the critical current density in the corrosion experiment decrease as the implanted nitrogen ion dose increases from 5*1015 to 1*1017 ions/cm2. The identification of products formed during corrosion experiment has been attempted with the help of conversion electron Mössbauer spectroscopy (CEMS), X-ray diffraction (XRD) and X-ray photoemission spectroscopic (XPS) techniques, and the possible mechanism of reactions is discussed with reference to their results. 相似文献
69.
70.
An efficient, simple, and environmentally friendly synthesis of a series of chromeno[2,3-d]pyrimidine-trione derivatives has been accomplished via the three-component reaction of a barbituric acid, dimedone/cyclohexane-1,3-dione, and aromatic aldehydes using Sc(OTf)3 as a recyclable catalyst under solvent-free condition. This method exploits the use of Sc(OTf)3 as a Lewis acid catalyst in organic synthesis and offers many rewards such as excellent product yield and easy work-up procedure. Harmless reaction conditions, as well as the absence of side-products, are another green aspects of this protocol. 相似文献