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101.
D. P. Bhattacharyya R. Rakshit B. Basu P. Pal S. Biswas N. Durgaprasad 《Il Nuovo Cimento C》1992,15(3):341-347
Summary A search has been made on the charge-changing partial cross-sections by using 0.927 GeV/n238U ion from LBL BEVALAC projected at an angle 30° on27Al target and CR-39 (DOP) was used as analyser. The irradiated plastic sheets were duly etched for one hour in 6.25N NaOH
solution and about 1680 cone lengths at both the surfaces of the CR-39 (DOP) sheets were optically measured. The cone length
distribution exhibits the existence of U fragments in the charge range 84≤Z≤91 and the estimated partial cross-sections range from 60 to 400 mb. The present data are in accord with the fit to the extrapolated
data of Binnset al. 相似文献
102.
Following Morris’s [5] consideration of a sourceless abelian gauge string in a Robertson-Walker universe with flat space sections
we have generalized the treatment to the case of arbitrary spatial curvature. We find that creation or destruction of the
gauge string is not possible if the spatial curvature is nonzero. 相似文献
103.
57Fe Mössbauer spectra of pulsed-laser deposited (PLD) films of CoFe2O4 of 0.3 µm thickness is investigated using transmission geometry is reported. Mössbauer parameters were determined for the tetrahedral (A) and octahedral (B) sites. The PLD processed films gave measurable spectra with no visible evidence of clustering or multiple phases present. Results on the films agreed with those of the bulk material. The films exhibited magnetic hyperfine and quadruple splittings similar to that of bulk CoFe2O4. This work demonstrates that measurable transmission Mössbauer spectra may be obtained for PLD deposited CoFe2O4 thick films. 相似文献
104.
Nanocrystalline ?-Fe3?x Ni x N (0.0?≤?×?≤?0.8) particles are synthesized by precursor technique and nitridation of decomposed products in NH3 (g) in the temperature range 673 K-823 K. For x?=?0.1–0.4 compositions, single phase ?-Fe3?x Ni x N hexagonal structure with space group P63/mmc is formed, while for x?=?0.5–0.8, fcc γ′-Fe4?y Ni y N phase is also precipitated. The room temperature Mössbauer spectrum for all the compositions shows the presence of superparamagnetic doublet, which is attributed to ?-Fe3?x Ni x N phase. For x?=?0.5–0.8 compositions, two additional sextets are observed corresponding to two different iron sites, the corner position (Fec) and the fcc position (Fef), in γ′-Fe4?y Ni y N. The added Ni atoms preferentially substitute the corner Fec positions. The isomer shift, quadrupole splitting and hyperfine field values are found to change with the Ni content. 相似文献
105.
Synthesis of Nanoscale Bimetallic Particles in Polyelectrolyte Membrane Matrix for Reductive Transformation of Halogenated Organic Compounds 总被引:2,自引:0,他引:2
Nanosized Fe/Ni and Fe/Pd particles were synthesized in the polyacrylic acid (PAA)/polyether sulfone (PES) composite membrane matrix for reductive transformation of halogenated organic compounds (HOCs). The advantages of using membrane to immobilize nanoparticles are the reduction of particles loss, prevention of particles agglomeration, and potential application of convective flow. Cross-linked PAA/PES composite membranes containing metal ions as particles precursor were prepared by heat treatment with ethylene glycol (EG) as a cross-linking agent. Nanoscale metal particles were formed and immobilized inside the membrane matrix after reduction with sodium borohydride. Membrane morphology and structure were observed by scanning electron microscopy (SEM). Particle size and distribution were characterized by SEM and transmission electron microscopy (TEM). Energy dispersive X-ray spectroscopy (EDS) was used to obtain the qualitative and quantitative element information of particles. A specimen-drift-free EDS line profile and EDS mapping system was performed in a scanning transmission electron microscopy (STEM) to determine the two-dimensional element distribution of iron and nickel in the nano domain. In the dechlorination study with trichloroethylene (TCE) as a representative HOCs, rapid and complete destruction of TCE was achieved by using nanosized bimetallic Fe/Ni or Fe/Pd in PAA/PES composite membranes. Typically more than 95% of 10 mg/l TCE was reduced within 1 h. Ethane was found in the headspace as the main product. 相似文献
106.
107.
Indranil Sinha Dr. Célia Fonseca Guerra Prof. Dr. Jens Müller 《Angewandte Chemie (International ed. in English)》2015,54(12):3603-3606
The first parallel‐stranded DNA duplex with Hoogsteen base pairing that readily incorporates an Ag+ ion into an internal mispair to form a metal‐mediated base pair has been created. Towards this end, the highly stabilizing 6 FP ‐Ag+‐ 6 FP base pair comprising the artificial nucleobase 6‐furylpurine ( 6 FP ) was devised. A combination of temperature‐dependent UV spectroscopy, CD spectroscopy, and DFT calculations was used to confirm the formation of this base pair. The nucleobase 6 FP is capable of forming metal‐mediated base pairs both by the Watson–Crick edge (i.e. in regular antiparallel‐stranded DNA) and by the Hoogsteen edge (i.e. in parallel‐stranded DNA), depending on the oligonucleotide sequence and the experimental conditions. The 6 FP ‐Ag+‐ 6 FP base pair within parallel‐stranded DNA is the most strongly stabilizing Ag+‐mediated base pair reported to date for any type of nucleic acid, with an increase in melting temperature of almost 15 °C upon the binding of one Ag+ ion. 相似文献
108.
Dr. Arik Kar Sumanta Sain Dr. Simanta Kundu Arka Bhattacharyya Dr. Swapan Kumar Pradhan Prof. Amitava Patra 《Chemphyschem》2015,16(5):1017-1025
Tuning the functional properties of nanocrystals is an important issue in nanoscience. Here, we are able to tune the photocatalytic properties of SnO2 nanocrystals by controlling their size and shape. A structural analysis was carried out by using X‐ray diffraction (XRD)/Rietveld and transmission electron microscopy (TEM). The results reveal that the number of oxygen‐related defects varies upon changing the size and shape of the nanocrystals, which eventually influences their photocatalytic properties. Time‐resolved spectroscopic studies of the carrier relaxation dynamics of the SnO2 nanocrystals further confirm that the electron–hole recombination process is controlled by oxygen/defect states, which can be tuned by changing the shape and size of the materials. The degradation of dyes (90 %) in the presence of SnO2 nanoparticles under UV light is comparable to that (88 %) in the presence of standard TiO2 Degussa P‐25 (P25) powders. The photocatalytic activity of the nanoparticles is significantly higher than those of nanorods and nanospheres because the effective charge separation in the SnO2 nanoparticles is controlled by defect states leading to enhanced photocatalytic properties. The size‐ and shape‐dependent photocatalytic properties of SnO2 nanocrystals make these materials interesting candidates for photocatalytic applications. 相似文献
109.
Synthesis of titanium oxide film by plasma oxidization of the metallic films is investigated. Argon/oxygen gas mixture in the pressure range 30 × 10?2 mbar is used for plasma processing at a frequency of 250 kHz. The plasma‐oxidized films are annealed in a tube furnace in argon atmosphere to establish crystalline‐phase formation. X‐ray diffraction and Raman spectroscopic results manifest peaks corresponding to rutile TiO2. Ultraviolet‐Visible (UV‐Vis) spectroscopic analysis confirms the bandgap of rutile TiO2, and photoluminescence spectra exhibit peaks due to oxygen defects. Homogeneity across the film's thickness and the nature of the film substrate interface is studied by depth profiling acquired using secondary ion mass spectrometry. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
110.
Tamoghna Bhattacharyya Arumoy Chatterjee Budhaditya Chatterjee Sufi O. Raja Anjan Kr. Dasgupta 《Electrophoresis》2015,36(24):3009-3013
We report both the experimental and theoretical insights of differential electro‐diffusion behavior of carbon nanomaterials (e.g. single wall, multiwall carbon nanotubes, and graphene). We thus discriminate one from the other in a soft gel system. The differential mobility of such material depends on their intrinsic properties, both extend and rate of migration bearing the discriminatory signature. The mobility analysis is made by a real time monitoring of the respective bands. 相似文献