Reconfigurable self-sufficient traps for ultracold atoms based on a superconducting square

We report on the trapping of ultracold atoms in the magnetic field formed entirely by persistent supercurrents induced in a thin film type-II superconducting square. The supercurrents are carried by vortices induced in the 2D structure by applying two magnetic field pulses of varying amplitude perpendicular to its surface. This results in a self-sufficient quadrupole trap that does not require any externally applied fields. We investigate the trapping parameters for different supercurrent distributions. Furthermore, to demonstrate possible applications of these types of supercurrent traps we show how a central quadrupole trap can be split into four traps by the use of a bias field.Comment: 5 pages, 7 figure

Measurement of Spin Polarization by Andreev Reflection in Ferromagnetic In1-xMnxSb Epilayers

We carried out Point Contact Andreev Reflection (PCAR) spin spectroscopy measurements on epitaxially-grown ferromagnetic In1-xMnxSb epilayers with a Curie temperature of ~9K. The spin sensitivity of PCAR in this material was demonstrated by parallel control studies on its non-magnetic analog, In1-yBeySb. We found the conductance curves of the Sn point contacts with In1-yBeySb to be fairly conventional, with the possible presence of proximity-induced superconductivity effects at the lowest temperatures. The experimental Z-values of interfacial scattering agreed well with the estimates based on the Fermi velocity mismatch between the semiconductor and the superconductor. These measurements provided control data for subsequent PCAR measurements on ferromagnetic In1-xMnxSb, which indicated spin polarization in In1-xMnxSb to be 52 +- 3%

Control Laws for a Dual-Spin Stabilized Platform

This paper describes two attitude control laws suitable for atmospheric flight vehicles with a steady angular momentum bias in the vehicle yaw axis. This bias is assumed to be provided by an internal flywheel, and is introduced to enhance roll and pitch stiffness. The first control law is based on Lyapunov stability theory, and stability proofs are given. The second control law, which assumes that the angular momentum bias is large, is based on a classical PID control. It is shown that the large yaw-axis bias requires that the PI feedback component on the roll and pitch angle errors be cross-fed. Both control laws are applied to a vehicle simulation in the presence of disturbances for several values of yaw-axis angular momentum bias. It is seen that both control laws provide a significant improvement in attitude performance when the bias is sufficiently large, but the nonlinear control law is also able to provide improved performance for a small value of bias. This is important because the smaller bias corresponds to a smaller requirement for mass to be dedicated to the flywheel

CMG-Augmented Control of a Hovering VTOL Platform

This paper describes how Control Moment Gyroscopes (CMGs) can be used for stability augmentation to a thrust vectoring system for a generic Vertical Take-Off and Landing platform. The response characteristics of the platform which uses only thrust vectoring and a second configuration which includes a single-gimbal CMG array are simulated and compared for hovering flight while subject to severe air turbulence. Simulation results demonstrate the effectiveness of a CMG array in its ability to significantly reduce the agility requirement on the thrust vectoring system. Albeit simplifying physical assumptions on a generic CMG configuration, the numerical results also suggest that reasonably sized CMGs will likely be sufficient for a small hovering vehicle

Investigation of single nucleotide polymorphisms in porcine candidate genes for blood component traits in pigs

This study used 209 public single nucleotide polymorphism (SNP) arrays for 151 candidate genes of pigs to analyse their association with nine blood component traits (insulin-like growth factor-I, insulin, immuno globulin, lymphocyte, monocyte, eosinophil, basophil, neutrophil and atypical lymph) in 209 Korean native pigs and Yorkshire F2 hybrids. Of these, 52 SNPs in 49 candidate genes showed significant association with one or more blood component traits. Nineteen of these SNPs were found to be present in blood component QTL regions. The 49 candidate genes corresponding to 52 SNPs with significant effects were detected and used for gene ontology analysis to understand the function of the candidate genes at molecular level. Based on functional classification (biological process, cellular components, and molecular function) of annotated candidates, 34 candidate genes (11 genes of IGF-1, 9 of IS, 9 of IG, 6 of NP, and 3 of EP) were detected. Additionally, eight genes (PSMB4, PSME3, MAPKAPK3, CTLA4, CUL7, GGT1, IDH3B, and RXRB) interacting with four immune pathways (immune system, adaptive immune system, Class I MHC-mediated antigen processing and presentation, and antigen processing: ubiquitination and proteasome degradation) were found through pathway and network analyses. The eight candidate genes identified in this study are included in class I MHC-mediated antigen pathway, which is an important factor that determines the success of organ transplantation in addition to the improvement of diseases and immunity of pigs. Therefore, these genes can potentially be used in heterogeneous organ research in future research.Keywords: Association analysis, gene network, pathway, SNP, swin

The Physics of Supernova Remnant Blast Waves. I. Kinematics of DEM L71 in the Large Magellanic Cloud

We present the results from Fabry-Perot imaging spectroscopy of the Balmer-dominated supernova remnant DEM L71 (0505-67.9) in the LMC. Spectra extracted from the entire circumference of the blast wave reveal the broad and narrow component H-alpha line emission characteristic of non-radiative shocks in partially neutral gas. The new spectra of DEM L71 include portions of the rim that have not been previously observed. We find that the broad component width varies azimuthally along the edge of DEM L71, ranging from 450+/-60 km/s along the eastern edge to values as high as 985 (+210)(-165) km/s along the faint western edge. In part of the faint northern rim the broad component is not detected, possibly indicating a lower density in these regions and/or a broad component width in excess of 1000 km/s. Between the limits of zero and full electron-ion temperature equilibration at the shock front, the allowed range of shock velocities is 430-560 km/s along the east rim and 700-1250 km/s along other parts of the blast wave. The H-alpha broad-to-narrow flux ratios vary considerably around the remnant, ranging from 0.4 to 0.8. These ratios lie below the values predicted by our shock models. We find that narrow component H-alpha emission from a cosmic ray precursor may be the cause of the discrepancy. The least decelerated portions of the blast wave (i.e., regions excluding the brightest filaments) are well characterized by Sedov models with a kinetic energy E_51= (0.37+/-0.06)*D_50**(5/2), where D_50 is the LMC distance in units of 50 kpc. The corresponding age for DEM L71 is (4360+/-290)*D_50 yr. This is the first time that velocity information from the entire blast wave has been utilized to study the global kinematics of a non-radiative SNR at a known distance.Comment: 21 pages, including 8 postscript figures and 4 tables, LaTeX, accepted to ApJ; see companion pape

Vibrations of closed-shell Lennard-Jones icosahedral and cuboctahedral clusters and their effect on the cluster ground state energy

Vibrational spectra of closed shell Lennard-Jones icosahedral and cuboctahedral clusters are calculated for shell numbers between 2 and 9. Evolution of the vibrational density of states with the cluster shell number is examined and differences between icosahedral and cuboctahedral clusters described. This enabled a quantum calculation of quantum ground state energies of the clusters in the quasiharmonic approximation and a comparison of the differences between the two types of clusters. It is demonstrated that in the quantum treatment, the closed shell icosahedral clusters binding energies differ from those of cuboctahedral clusters more than is the case in classical treatment