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1.
l-(o-Carboxyphenyl)-3-hydroxy-3-methyltriazene is proposed as an excellent reagent for the spectrophotometric determination of iron(III) and titanium(IV), and also for the separation of titanium from a large quantity of iron as well as other cations and anions. Iron(III) forms an anionic violet 1:2 complex at pH 4.0–9.4, and a cationic green 1:1 complex at pH 1.5–2.0, with absorption maxima at 570 nm and 660 nm, respectively. The violet complex is quantitatively extracted in chloroform containing n-octylamine at pH 3.0–9.0. The green and the violet iron(III) complexes obey Beer's law, the respective optimal ranges being 8.9–35.8 and 3.9–11.2 p.p.m. The yellow titanium chelate extracted into chloroform (absorption maximum at 410 nm) between pH 1.0 and 3.5, can be re-extracted into concentrated sulphuric acid a violet colour being produced with absorption maximum at 530 nm. Beer's law is obeyed in the ranges 0.8–5.7 p.p.m. for the titanium complex in chloroform and 3.4–19.2 p.p.m. when extracted in concentrated sulphuric acid. Interferences from diverse ions are not severe. Procedures for the separation and determination of titanium in the presence of a large quantity of iron are given. The isolation of the iron(III) and vanadium(IV and V) complexes, and their properties, are described. 相似文献
2.
The use of di(2-ethylhexyl)phosphoric acid (HDEHP) as an extractant for the separation of molybdenum from tungsten was examined with the help of molybdenum-99 and tungsten-187 as radiotracers. Effective separation was obtained when the aqueous phase contained phosphoric acid at pH 0.8–2 or pH 3–3.5, depending on the amounts of metal. The method is applicable to both tracer and milligram amounts of molybdenum. The structure of the extracted species was examined by infrared spectroscopy. 相似文献
3.
Titanium phosphate as ion exchanger for column operation has been prepared by mixing TiCl4 and H3PO4 in suitable proportion. The ratio of titanium: phosphate was obtained to be 1:2.02. The uptake of Na+, K+, Rb+, Cs+, Ag+, Ca2+, Sr2+, Ba2+, Pb2+, Sc3+, Co3+, Y3+, Tb3+, Zr4+ and Th4+ cations at very small concentrations has been studied on this exchanger. The data indicated that the different cations are adsorbed in the exchanger by different mechanisms. Radiochemical separations of carrier free95Nb from95Zr, UX1 from U and45Ca from46Sc have been achieved by adopting very simple chemical procedures through a column of titanium phosphate. The -spectrum of the separated95Nb, UX1 and46Sc showed that the products are of high radionuclidic purity. The individual separation procedures took less than 20 min and the yields are quantitative. 相似文献
4.
K. Chabita P. C. Mandal S. N. Bhattacharyya 《Journal of Radioanalytical and Nuclear Chemistry》1994,188(2):133-148
Dilute aqueous solutions of cytosine were irradiated with60Co -rays under N2O saturated conditions at different pH and in the presence of Cu(II) ions at neutral pH. The base degradation decreased from neutral to acidic and basic conditions. In the presence of metal ions at neutral pH conditions there was a significant increase in the base degradation compared to that in the absence of metal ions under similar conditions. From the difference absorption spectra and fluorescence behavior of the irradiated solutions it was observed that the major radiolytic products of cytosine under different conditions are cytosine glycols, 5-hydroxycytosine, hydroxy-hydrocytosine and cytosine dimers. The yields of dimers is maximum in neutral conditions and it decreased from basic to acidic conditions. However, in the presence of Cu(II) ions formation of cytosine dimers is completely restricted and there is an increase in the yields of cytosine glycol, hydroxy-hydrocytosine and 5-hydroxycytosine. From the post-radiolytic changes in absorption and fluorescence behavior of irradiated solutions, it is revealed that some of the radiolytic products, namely cytosine glycol and hydroxy-hydrocytosine decompose to 5-hydroxycytosine and cytosine, respectively. 相似文献
5.
N. R. Das P. S. Chakraborty S. N. Bhattacharyya 《Journal of Radioanalytical and Nuclear Chemistry》1977,36(2):419-425
Present investigation deals with neutron activation analysis of gold in some varieties of geological samples related to auriferous
quartz veins. A few plant specimens of the area were also analyzed. The gold contents in the rock samples as determined by
the destructive way of analysis vary in the range 10−5 to 10−7%. In case of plant samples, however, the non-destructive method of analysis of the plant ashes was followed and the concentration
of gold was found to be of the order of 10−5%. In plants, besides gold, some associated elements, such as La, Ce, Sm, Lu, Zr, Hf, Se, W, As and Sb were also identified. 相似文献
6.
The specific heat C and thermal conductivity κ of polybutadiene are characteristic of all non-crystalline materials at temperatures below ≈ K, reflecting the presence of localized excitations. The changes in C and κ with variation in crosslinking suggest that the relaxation times of the localized excitations may vary with crosslink density. Extension of an elastomer does not reveal a change in density of localized excitations as monitored by measuring κ, possibly because other phonon scattering mechanisms mask the effect. For T ? 10 K the phonon mean-free-path is independent of the microscopic anisotropy of the elastomer. 相似文献
7.
One of the interesting properties of the NMSSM is that it can accommodate a light pseudoscalar of order 10 GeV. However, such scenarios are challenged by several experimental constraints, especially those related to the fermionic decays of the pseudoscalar. In this Letter, we extend the NMSSM field content by two gauge singlets, with lepton numbers +1 and −1. This serves the twin purpose of generating neutrino masses via the inverse seesaw mechanism and keeping the option of a very light pseudoscalar experimentally viable by opening dominant invisible decay channels of the pseudoscalar which help it evade the existing bounds. 相似文献
8.
Sunanda Banerjee Rohini M Godbole Sreerup Raychaudhuri Ben Allanach Sunanda Banerjee Satyaki Bhattacharyya Debajyoti Choudhury Siba Prasad Das Anindya Datta Rohini M Godbole Monoranjan Guchait Sabine Kraml Gobinda Majumdar David Miller Margarete Mühlleitner Nobuchika Okada Maxim Perelstein Santosh K Rai Sreerup Raychaudhuri Saurabh D Rindani DP Roy K Sridhar Rishikesh Vaidya D Zeppenfeld 《Pramana》2006,67(4):617-637
This is summary of the activities of the working group on collider physics in the IXth Workshop on High Energy Physics Phenomenology
(WHEPP-9) held at the Institute of Physics, Bhubaneswar, India in January 2006. Some of the work subsequently done on these
problems by the subgroups formed during the workshop is included in this report. 相似文献
9.
10.
In this paper, the design and analysis of an ultracompact coupler based on a hybrid silicon plasmonic waveguide (HSPW) is proposed and its coupling and crosstalk characteristics have been theoretically investigated for the development of optical interconnects that can be realized using well-established complementary metal-oxide-semiconductor-compatible fabrication techniques. To determine the minimum horizontal separation distance and efficient coupling length for the designed coupler, the symmetric and antisymmetric supermodes are obtained and their characteristics are studied at a wavelength of 1.55 μm. Efficient light coupling is exhibited by the HSPW coupler with 75 % of power transfer between the two HSPWs with ultrashort coupling length of 2.14 μm when the separation distance is 50 nm. Further, it is shown that the crosstalk is significantly reduced with the insertion of metallic strip between the two HSPWs for realizing highly dense integrated plasmonic circuits. 相似文献