Hysteresis studies in Clarke solder-blob junctions

A study of hysteresis in Clarke solder-blob junctions has been carried out in the temperature range 4.2–1.2 K. The temperature dependence of the critical current, the variation of the constant-temperature critical current with sequential sweep cycles, and the effects of an external field are studied. All the experimental results are explained as due to a net trapping of magnetic flux in the junction loop whenever a hysteretic curve is traced. The origin of the flux can be traced to the inductance of the superconducting loop and the electrical or geometrical asymmetry.     

Comparative Study of Antioxidant Activity of the Food Flowers of West Bengal,India

In India, many flowers are consumed as food. During the present study, 37 flowers have been analyzed for their 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and total antioxidant capacity. The flowers were found to have different levels of antioxidant properties in the systems tested. On the basis of the activity and availability, a few flowers were further studied for hydroxyl radical scavenging activity, superoxide radical scavenging activity, lipid peroxidation prevention, and DNA damage prevention properties. The correlations suggest that the total phenol contents of the flowers were responsible for the antioxidant properties of the aqueous extracts. The unweighted-pair group average dendrogram showing interrelationships between the investigated species grouped them into two high level clusters based on activity.     

Streptococcus thermophilus strains: Multifunctional lactic acid bacteria

Streptococcus thermophilus has “Generally Recognized as Safe” status and is extensively used for the manufacture of several important fermented dairy foods, including yoghurt and some cheese varieties (Swiss, Limburger, Brick). S. thermophilus also has a number of functional activities such as production of extracellular polysaccharides, bacteriocins and vitamins. In addition, it also has potential as a probiotic, as demonstrated by various health effects, transient survival, and moderate adherence in the gastrointestinal tract. Therefore, the natural diversity among S. thermophilus strains with respect to their capacity to produce different metabolites has the potential to be exploited beyond fermentation for lactic acid production.     

Recent Trends in Novel Semiconductor Devices

Silicon - The VLSI industry has grown a lot for several decades. The Packing density of integrated circuits has been increased without compromising the functionality. Scaling of semiconductor...     

Boosting the Performance of ZnO/CdS Core-Shell Nanorod Array-based Solar Cells by ZnS Surface Treatment

With a view to enhancing the efficiency of ZnO/CdS core-shell nanorod array-based semiconductor sensitized solar cells (SSSCs), ZnS surface treatment is envisioned. It is achieved through a thin layer of ZnS being deposited onto ZnO/CdS film by a successive ionic layer adsorption and reaction (SILAR) technique. To ascertain the optimum thickness of ZnS and to enhance the solar cell performance, we have varied the number of SILAR cycles of ZnS deposition. The optimized film is then considered for structural, morphological, and electrochemical studies. The analysis reveals the benefits of ZnS surface treatment on ZnO/CdS core-shell photoelectrodes in terms of an enhancement of solar cell performance of up to 1.54 % from 1.23 %.     

Mechanical properties of mica‐filled PBT/ABAS composites

Tensile properties and Izod impact strength of mica‐filled composites of poly(butylene terephthlate) (PBT)/polyacrylonitrile‐butyl acrylate‐styrene (ABAS) were studied at mica concentration range 0 to 0.14 volume fraction, (?_f). Tensile properties such as tensile modulus, strength, and breaking strain were normalized by dividing the data with the crystallinity (%) of the major component PBT in the composites and the matrix blends. The normalized relative tensile properties were compared with simple models to evaluate the interphase interactions between the matrix (i.e. PBT/ABAS blend) and the dispersed phase mica. Mica reinforced the blend increasing the tensile modulus and strength with mica concentration while the strain‐at‐break was increased marginally up to ?_f = 0.04 and decreased beyond this ?_f. The impact strength, however, decreased with increase in ?_f due to enhanced matrix stiffening and lack of plastic deformation of the matrix. Scanning electron microscopic studies revealed good dispersion of mica in the composites. The effect of surface treatment with a zirconate coupling agent, NZ‐97, on the above properties has also been examined. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Coupled surface-enhanced Raman spectroscopy and electrical conductivity measurements of 1,4-phenylene diisocyanide in molecular electronic junctions

Probing the structure of molecules in a metal-molecule-metal junction under an applied voltage is critical for understanding molecular electron transport properties. We present an approach that allows recording surface-enhanced Raman spectra simultaneously with electrical measurements of a monolayer of molecules in molecular electronic junctions. 1,4-Phenylene diisocyanide in two different types of junctions was used to illustrate the approach. The results show that the molecular integrity was intact in the molecular junctions and under the applied bias. The monolayer sensitivity of the approach provides a new powerful tool for characterizing molecular structure in a molecular electronic junction.