[en] In water I₂ combines with methylene blue, thionine, pararosaniline, crystal violet and acridine orange, and solid complexes precipitate out. The complex with methylene blue is 1:1 and shows a new absorption band in CHCl₃ at 365 nm. It appears to be of the electron donor-acceptor type: n (dye)→sigma (I₂). (auth.)

[en] An expression for the pair distribution function, g^+-(r) of electrons around a finite-mass positively charged point defect in a one-component classical rare plasma, is derived in the linear response theory. The expression for gsup(+-)(r) is quite involved and different from that corresponding to the infinite-mass point defect. The dependence of gsup(+-)(r) on the temperature of the system and the mass of the point defect has been studied and reported for a given system. (author)

[en] Suppression of superconducting property in presence of inhomogeneous spin distribution in GdBa_2Cu_3_−_xCo_xO_6_._9 has been studied. A superconducting sample without Co exhibits superconducting transition at 56.1 K. The current-voltage (I-V) characteristics exhibit nonlinear to linear transformation above a certain temperature. Two other samples (i) with Co and (ii) without Cu are found to be nonsuperconducting with very high resistive in nature at lower temperature. Localization length decreases with the increase in Co substitution. Suppression of the superconducting transition has been attributed to the change in the magnetic fluctuations induced by the randomness in spin substitution. An exponent has been extracted to understand the current-voltage behaviour. Kosterlitz-Thouless (KT) transition may be affected strongly by the shifting of magnetic fluctuations.

[en] Magnetic system is one of the main subsystem of SST-1 Tokamak [2] and it consists of superconducting toroidal field (TF) and poloidal field (PF) magnets. The Poloidal Field coils in SST-1 are wound from stainless steel jacketed Cable in Conduit Conductor (CICC). The insulation is provided by fibre glass tape and the winding pack is epoxy impregnated. The PF coils are subjected to electromagnetic loads. The PF coils and other coils (which determine the forces on PF coils) are modeled in ANSYS and an EMAG analysis is done to obtain the Lorentz forces on the conductors followed by a structural analysis done using effective properties. After the first level solution, the region of maximum stress is re-meshed in detail and the peak Von-Mises stress and the mean peak Von-Mises stresses are determined in the SS conduit (of the conductor) and the insulation material. The support system for the PF coils is designed taking into account the electromagnetic forces and the space available in the machine. (author)

[en] The resistivity as a function of temperature of GdBa₂Cu_3-xAg_xO_7-δ superconductors reveals that the critical temperature, T_c, increases with the concentration of Ag (x). An equation has been suggested to understand the behaviour of T_c (x). The coherence length has been extracted on the basis of the three dimensional Aslamazov-Larkin (3DAL) equation to understand the enhancement in the critical temperature. We have studied current-voltage (IV) curves below T_c to understand the nonlinearity observed in doped samples. An exponent has been extracted to explore the possibility of Kosterlitz-Thouless (KT) transition and the role of the coherence length in the nonlinear behaviour.

[en] In this article, the D-dimensional Klein-Gordon equation within the framework of Greene-Aldrich approximations scheme for Hua potential is solved for s-wave and arbitrary angular momenta. The energy eigenvalues and corresponding wave functions are obtained in an exact analytical manner via the Nikiforov-Uvarov (N-U) method. Further, it is shown that in the non-relativistic limit, the energy eigenvalues reduces to that of Schrödinger equation for the potential. Our results are in excellent agreement with other related works. Key words: Hua potential, Greene-Aldrich approximation, Nikiforov- Uvarov (N-U) method. (author)

[en] We present a detailed thermal and structural analysis of a four-cell prototype Plane Wave Transformer (PWT) linac structure, resonating at the designed frequency of 2856 MHz in the π mode. There is a provision for water cooling through channels in the disks brought by supporting tubes. A thermal and structural analysis has been performed using ANSYS6.1 finite element code. The maximum temperature rise and changes in dimensions in the structure have been studied. The transient temperature rise in the walls due to the 10μs RF pulse has been obtained in copper and copper plated SS walls. (author)

[en] A variable energy electron beam transport line has been designed to transport a 15-25 MeV electron beam from the injector linac to the undulator of a tuneable infra-red free electron laser (IR-FEL) being built at the Raja Ramanna Centre for Advanced Technology ( RRCAT). Beam optics of this transport line, which uses a dog-leg type bend, has been designed to match the twiss parameters of the beam to that of the undulator as per FEL design requirements and keep the beam envelop within acceptable limits through out the transport line. In this paper, we discuss the evolution of design of electron beam optics from the linac to the undulator. (author)

[en] In IR-FEL, to protect the optical sensors in hexapod and undulator from the back scattered gamma rays coming from the beam dump, another dipole was planned to bend away the 15-35 MeV electron beam. The spent beam in an FEL has typically a few percent energy spread, leading to large beam excursions towards the beam dump. To control this a dump dipole bend optics was designed. A compact 22.5 degree bend, parallel edge, H-type dipole magnet with a larger 63 mm pole gap was conceived. The magnet was designed in POISSON to maximize the good field region and dipole strength. Then the entry and exit pole chamfers were designed in ANSYS 3D. The magnet has been designed, developed and commissioned with 15-19 MeV beam in IR-FEL using BPMs before and after the dump dipole. (author)

[en] Bound state solutions of the Dirac equation for the Kratzer-Fues potential with spin and pseudo-spin symmetry are studied in this paper. To obtain the exactly normalized bound state wave function and energy expressions we have used the Laplace transform approach