Study of ground state phases for spin-1/2 Falicov-Kimball model on a triangular lattice

The spin-dependent Falicov-Kimball model (FKM) is studied on a triangular lattice using numerical diagonalization technique and Monte-Carlo simulation algorithm. Magnetic properties have been explored for different values of parameters: on-site Coulomb correlation $U$, exchange interaction $J$ and filling of electrons. We have found that the ground state configurations exhibit long range Ne\`el order, ferromagnetism or a mixture of both as $J$ is varied. The magnetic moments of itinerant ($d$) and localized ($f$) electrons are also studied. For the one-fourth filling case we found no magnetic moment from $d$- and $f$-electrons for $U$ less than a critical value.Comment: 6 pages, 8 figure

Interface induced perpendicular magnetic anisotropy in Co/CoO/Co thin film structure: An in-situ MOKE investigation

Co /CoO/Co polycrystalline film was grown on Si (001) substrate and magnetic properties have been investigated using in-situ magneto-optic Kerr effect during growth of the sample. Magnetic anisotropy with easy axis perpendicular to the film surface has been observed in top Co layer, whereas bottom layer was found to be soft with in-plane magnetization without any influence of top layer. Ex-situ in-plane and out-of-plane diffraction measurements revealed that the growth of Co on oxidized interface takes place with preferential orientation of c-axis perpendicular to the film plane, which results in the observed perpendicular magnetic anisotropy. Texturing of the c-axis is expected to be a result of minimization of the interface energy due to hybridization between Co and oxygen at the interface.Comment: 9 pages, 3 figures, under review in IOP journa

Optimization and characterization of a microscale thermal field-flow fractionation system

Journal ArticleA thorough investigation of the design considerations for microscale thermal field-flow fractionation and characterization of a 25 μm thin microscale thermal field-flow fractionation system is reported. A 4-50 times volume reduction from mesoscale and macroscale systems warrants customized design and operational conditions for microscale separation systems. Theoretical calculations are done to illustrate the importance of the increased dispersion due to extra-column tubing, off-chip detection and sample injection volume with reduced channel dimensions. An optimized microscale thermal field-flow fractionation (ThFFF) channel is fabricated using rapid and cost effective manufacturing and assembly processes. Specifically, improvements in material selection and arrangement are implemented to achieve higher particle retentions. The new instrument arrangement includes high conductivity silicon as the cold wall and a thin polymer layer with low thermal conductivity as the hot wall which results in high temperature gradients (~ 106 ºC/m) across the microchannel and subsequently high retention. Single particle retention separations are carried out with polystyrene nanoparticle samples in an aqueous carrier to characterize the device and demonstrate the improvements

Characterization of a microscale thermal-electrical field-flow fractionation system

ManuscriptA microscale thermal-electrical field-flow fractionation (ThElFFF) channel is reported for the first time and preliminary characterization results show high retention at certain operating conditions including relatively high flow rates when compared to standard microscale electrical or thermal field-flow fractionation instruments. A new design is presented that simplifies manufacturing and assembly of the prototype and that can provide both an electrical field and a high temperature gradient (~ 106 ?C/m). Monodisperse particle retention is carried out with polystyrene nanoparticle samples to characterize the device. Retention ratios as low as 0.045 are observed with the ThElFFF instrument. Size selectivity of 1.77 was achieved for ThElFFF. The comparison with theory shows a marked deviation from the existing theory. Separation of a mixture of polystyrene particles is demonstrated for first time using a ThElFFF system by separating 130 nm carboxylated polystyrene and 209 nm polystyrene particles

Comparison of pulmonary function of women in 2nd trimester and non-pregnant women, in central Uttar-Pradesh, India

Background: Pregnancy is nothing but a process of maternal adaptation to meet the increasing needs of the growing foetus. Significant changes in the highly sensitive respiratory system occurs during pregnancy to fulfil increased demands as well as to combat stress of pregnancy. Although many studies have been done in India to study the Pulmonary Functions during pregnancy, but due to paucity of such study in central Uttar-Pradesh this study was planned.Methods: This study was carried out on 353 2nd trimester pregnant women coming to ANC clinic of Obstetrics and Gynaecology Department of Uttar-Pradesh University of Medical Sciences, Saifai, Etawah, pulmonary function parameters were recorded using Computer based Digital Spirometer. Data were compared with pulmonary function parameters of age matched 353 Non-Pregnant controls. Parameters studied were FVC, FEV1, FEV1/FVC, PEFR and MVV.Results: FVC, FEV1, FEV1/FVC and PEFR was found less in pregnant women as compared to Non-pregnant women, difference was statistically highly significant (P<0.01). MVV was also found less in pregnant women but it was insignificant (P >0.05).Conclusions: All parameters of PFT are deranged in pregnancy. Matching of other attributes of cases and controls like height, pre-pregnancy weight of cases and weight of controls, Haemoglobin, BMI, could possibly further explain the established relationship of pregnancy and PFT parameter derangements. Perhaps, a longitudinal study in expectant mothers by measuring their PFT parameters in non-pregnant states and then serial follow-up PFT measurement during their pregnancy would be a better approach to look for the effects of pregnancy on PFT parameters

Магнитокоммутируемая микросхема и датчик измерения скорости ветра на ее основе

Разработанная магнитокоммутируемая микросхема на основе эффекта Холла позволила создать магнитный датчик скорости ветра.У статті представлено опис магн·токомутуємої мікросхе·ми на основі ефекту Холу. Приведені електрична схема розробленої МКМ і її основні технічні характеристики. Розроблено датчик швидкості вітру на її основі. Діапазон вимірювання швидкості вітру склав 0,5 - 50 м/с з похибкою ±5%.The magneto switch microcircuit on the base of Hall-effect is developed. The electric scheme of the magneto sensitive IC was designed and its basic technical characteristics are described. The gauge of wind speed on its base is fabricated