Indian Association for the Cultivation of Science

About: Indian Association for the Cultivation of Science is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Excited state & Catalysis. The organization has 3867 authors who have published 10457 publications receiving 220098 citations.

Electrical bistability and memory phenomenon in carbon nanotube-conjugated polymer matrixes.

Abstract: We have observed electrical bistability and large conductance switching in functionalized carbon nanotube (CNT)-conjugated polymer composites at room temperature. The concentration of the CNTs in the polymer matrix controlled the degree of bistability. Conduction mechanism applicable in each of the conducting states has been identified. The switching had an associated memory phenomenon and was reversible in nature. In the bistable devices, the active layer retained its high-conducting state until a reverse voltage erased it. We could "write" or "erase" a state and "read" it for many cycles for random-access memory applications.

Tuning of Crystal Phase and Luminescence Properties of Eu3+ Doped Sodium Yttrium Fluoride Nanocrystals

Abstract: We demonstrated an emulsion based wet chemical method for preparing Eu3+ doped cubic NaYF4 and hexagonal Na(Y1.5Na0.5)F6 nanocrystals. Here, we report the control of the crystal phase as a function of the Y3+/F- ratio and pH of the solution. It was found that cubic NaYF4 and hexagonal Na(Y1.5Na0.5)F6 nanocrystals were prepared at 1:4 and 1:8 Y3+/F- ratios, respectively. The hexagonal Na(Y1.5Na0.5)F6 and cubic NaYF4 phases appeared in the pH range of 6−7 and 2−3, respectively, indicating that the pH of the solution also plays an important role in tuning the crystal structure. The mechanism related to crystal phase control is proposed and discussed. It was also found that the emission intensity of the peak at 614 nm (5D0 − 7F2) for Eu3+ ions and decay time are sensitive to the crystal structure, which is again controlled by the Y3+/F- ratio and pH of the solution. Again, it is seen that the interlayered water molecules strongly influence the photoluminescence of Eu3+ ions up to 300 °C, which was confirmed b...

Fluorescence spectroscopic characterization of the interaction of human adult hemoglobin and two isatins, 1-methylisatin and 1-phenylisatin: a comparative study.

Abstract: In this report, steady state and time-resolved fluorescence along with circular dichroism (CD) spectroscopic, FTIR, and anisotropy investigations were made to reveal the nature of the interactions between human adult hemoglobin (Hb) and the isatins, 1-methylisatin (1-MI) and 1-phenylisatin (1-PI). From the analysis of the steady state and time-resolved fluorescence quenching of Hb in aqueous solution in the presence of an isatin, i.e., 1-MI, it seemed that the nature of the quenching was of static type and a mixture of both static and dynamic nature for 1-PI. The primary binding pattern between isatins and Hb has been interpreted as a combined effect of hydrophobic association and electrostatic interaction for 1-MI. For 1-PI, this was the combined effect of hydrophobic association and ionic interactions and salt bridges or/and proton transfer. The pretwisted structure of 1-PI facilitates ionic interactions with Hb. The binding constants, number of binding sites, and thermodynamic parameters had been compu...