Insulator superconductor transition on solid inert gas substrates

We present observations of the insulator-superconductor transition in ultrathin films of Bi on solid xenon condensed on quartz and on Ge on quartz. The relative permeability $\epsilon_{r}$ ranges from 1.5 for Xe to 15 for Ge. Though we find screening effects as expected, the I-S transition is robust, and unmodified by the substrate. The resistance separatrix is found to be close to $h/4e^2$ and the crossover thickness close to 25 $\AA$ for all substrates. I-V studies and Aslamazov-Larkin analyses indicate superconductivity is inhomogeneous. The transition is best described in terms of a percolation model.Comment: Submitted to LT23 Proceeding

Hammett Correlations in the \u3csup\u3e1\u3c/sup\u3eH NMR Spectra of Some N-Arlydihalonicotinamides

Excellent linear correlations of amide proton chemical shifts (Snh) (in DMSO-d6 ) with Hammett substituent constants (5) for a series of 4-substituted anilides of four dihalonicotinic acid systems were observed. Dihalonicotinanilides with chlorine in the pyridine 2 - position exhibited a more positive slope in a Hammett plot of S^H vs - aR- where R is the substituent in the 4 position of the benzene ring. This observation is explained in terms of the inductive effect of chlorine which results in a slightly more acidic amide proton, which in turn causes an enhanced hydrogen bonding tendency to solvent. Four disubstituted anilides were also prepared, and the 5NH of these derivatives correlated well with the additive value of the 6R\u27s of the two substituents

4-Substituted Anilides of 2,6- and 5,6- Dichlorolicotinic Acid. Potential Agricultural Agents

A series of 4-substituted anilides of 2,6- and 5,6 dichloronicotinic acid were prepared. The acids were first converted to their acid chlorides, which were in turn treated with the appropriate 4-substituted aniline in chloroform. A total of 16 anilides was thus prepared, and their structures confirmed. These compounds were prepared for testing as possible herbicidal, pesticidal or fungicidal agent

Development of EM-CCD-based X-ray detector for synchrotron applications

A high speed, low noise camera system for crystallography and X-ray imaging applications is developed and successfully demonstrated. By coupling an electron-multiplying (EM)-CCD to a 3:1 fibre-optic taper and a CsI(Tl) scintillator, it was possible to detect hard X-rays. This novel approach to hard X-ray imaging takes advantage of sub-electron equivalent readout noise performance at high pixel readout frequencies of EM-CCD detectors with the increase in the imaging area that is offered through the use of a fibre-optic taper. Compared with the industry state of the art, based on CCD camera systems, a high frame rate for a full-frame readout (50 ms) and a lower readout noise (<1 electron root mean square) across a range of X-ray energies (6–18 keV) were achieved

Vortices and the mixed state of ultrathin Bi films

Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin Bi films in a magnetic field are reported. These show hysteresis for all films, grown both with and without thin Ge underlayers. Films on Ge underlayers, close to superconductor-insulator transition, show a peak in the critical current, indicating a structural transformation of the vortex solid. These underlayers, used to make the films more homogeneous, are found to be more effective in pinning the vortices. The upper critical fields ($B_{c2}$) of these films are determined from the resistive transitions in perpendicular magnetic field. The temperature dependence of the upper critical field is found to differ significantly from Ginzburg-Landau theory, after modifications for disorder.Comment: Submitted to LT23 Proceeding

Determination of Hammett Pyridine 3-Aza and 4-Aza Replacement Constants by 1H NMR Studies of Amide Systems

Values for Hammett pyridine 3-aza and 4-aza replacement constants were obtained by correlation of the amide proton chemical shifts (in DMSO) of some N-(3-pyridyl)-and N-(4-pyridyl)-dichloronicotinamides, benzamides and acetamides with those of their N-(substituted phenyl) amide analogs using standard Hammett a value

LIBRARY AND INFORMATION NEEDS OF DIFFERENTLY-ABLED STUDENTS IN KERALA: A STUDY

The study was conducted to investigate the information needs of differently-abled students in the school libraries of Kerala. The study was done among students belonging to the category of visually challenged (VC), hearing and speech impaired (HI), and physically challenged (PC) from special schools and schools under Inclusive Education of the Disabled at Secondary Stage (IEDSS). The study was based on a questionnaire survey, conducted in the three districts of Kerala state ie; Thiruvananthapuram, Ernakulum & Kozhikode. The analyses revealed that the information needs of differently-abled students have become complex and problematic due to the insufficiency of adequate information sources and services and there are quite a number of challenges faced by these students in accessing information from the libraries. The overall result of the study was that, though the library services provided in the school are useful for their studies, the respondents cannot make use of them because of barriers. The study comes out with some practical suggestions to improve the library services for differently-abled student

Impact of Medical Education Trend in Community Development

Problem-based learning has been described as one of the most significant developments in medical education. The trend of medical education plays a vital role in determining the success of universal health coverage in India.&nbsp; The motto of health education is community-based training, where students are placed in the community and learn by delivering the care using the existing health services