Au4V – Moment Stability and Spin Fluctuations in the Ordered Phase

Although neither gold nor vanadium generally possess a magnetic moment, the intermetallic compound Au4V is found to be ferromagnetic below 42K. In this paper we report the results of a muon spin relaxation study of the itinerant electron moment fluctuations in Au4V above the Curie temperature. The temperature dependence of the muon spin relaxation rate is found to be similar to that of the weak itinerant helimagnet, MnSi

Family Size and Risk of Juvenile Idiopathic Arthritis: A Cross-Sectional Study

Background: Juvenile idiopathic arthritis (JIA) refers to a group of auto-immune conditions involving joint inflammation that first appears before the age of 16. In the United States, about 294,000 children are affected. Although JIA can be widely attributed to genetic factors, the consensus is that environmental factors also play a role. Attempts to assess the role of environmental factors, though scarce, have focused on the role of infections, smoking exposure, and breastfeeding. Hygiene hypothesis, which suggests that adaptive immunological response improves with higher frequencies of pathogen exposure in early childhood, has been used to try to explain the risk of JIA. Common markers of microbe exposure in early life include sibling number, pet number, and maternal parity. Some prior studies conducted outside the U.S. suggests that increasing sibling number is protective against the risk of JIA. This study aimed to evaluate prior findings, using data from the U.S. Methods: The study used data from the 2017 Centers for Disease Control and Prevention National Survey for Child Health. The survey used a sample size of 21599 children to estimate the number of children in the U.S. Descriptive statistics was carried out, and logistic regression was used to determine the association between family number and the odds of developing JIA, while adjusting for sociodemographic variables. Family number was used as a proxy for sibling number. SAS v 9.4 was used for analysis. Results: Complete data on all the variables of interest were available for 17618 children, of which 67 had JIA. Although there was a marginal association between sibling number and JIA in the unadjusted model (OR [95% CI] 0.983-1.602) (P=0.068), in the adjusted model, there was no significant association between JIA and sibling number ([OR 95% CI] 0.8985-1.447) (P=0.29). There was a significant association between JIA and age, low birth weight, highest education level in the family, while sex had a marginal association. Conclusion: There was no association between family size and the development of JIA in this study. While some prior results have supported the observed significant effect of low birth weight, the disparity in results between this study and the Australian study could be due to the use of family number instead of sibling number. Further studies should assess the association of sibling number and developing JIA in the U.S

Coulomb Breakup Mechanism of Neutron-Halo Nuclei in a Time-Dependent Method

The mechanism of the Coulomb breakup reactions of the nuclei with neutron-halo structure is investigated in detail. A time-dependent Schr\"odinger equation for the halo neutron is numerically solved by treating the Coulomb field of a target as an external field. The momentum distribution and the post-acceleration effect of the final fragments are discussed in a fully quantum mechanical way to clarify the limitation of the intuitive picture based on the classical mechanics. The theory is applied to the Coulomb breakup reaction of $^{11}$Be + $^{208}$Pb. The breakup mechanism is found to be different between the channels of $j^{\pi}=\frac{1}{2}^{-}$ and $\frac{3}{2}^{-}$, reflecting the underlying structure of $^{11}$Be. The calculated result reproduces the energy spectrum of the breakup fragments reasonably well, but explains only about a half of the observed longitudinal momentum difference.Comment: 15 pages,revtex, 9 figures (available upon request

Designing molecules to bypass the singlet-triplet bottleneck in the electroluminescence of organic light-emitting-diode materials

Electroluminescence in organic light emitting diode (OLED) materials occurs via the recombination of excitonic electrons-hole pairs Only the singlet excitons of commonly used OLED materials, e.g., Aluminum trihydroxyquinoline (AlQ$_3$), decay radiatively, limiting the external quantum efficiency to a maximum 25%. Thus 75% of the energy is lost due to the triplet bottleneck for radiative recombination. We consider molecules derived from AlQ$_3$ which bypass the triplet bottleneck by designing structures which contain strong spin-orbit coupling. As a first stage of this work, groundstate energies and vertical excitation energies of Al-arsenoquinolines and Al-boroarsenoquinolines are calculated. It is found that the substitution of N by As leads to very favourable results, while the boron substitution leads to no advantage.Comment: 4 pages, 4 figue

Critical Current Properties in Longitudinal Magnetic Field of YBCO Superconductor with APC

The critical current density (Jc) properties of the Artificial Pinning Center (APC) introduced YBa2Cu3O7 (YBCO) films in the longitudinal magnetic field were measured. Y2O3 or Y2BaCuO5 (Y211) was introduced as APCs to YBCO, and YBCO films with APC were fabricated on SrTiO3 single crystal substrate. The sizes of Y2O3 and Y211 were 5—10 nm and 10—20 nm, respectively. As a result, Jc enhancement in the longitudinal magnetic field was observed in Y2O3 introduced YBCO films. However, it was not observed in Y211 introduced YBCO films. Therefore, it was considered that Jc properties in the longitudinal magnetic field were affected by introducing of small size APC, and it was necessary that APC does not disturb the current pathway in the superconductor.28th International Symposium on Superconductivity, ISS 2015, November 16-18, 2015, Tokyo, Japa

A multinuclear NMR and quantum chemical study of solid trimethylammonium chloride

The solid salt, trimethylammonium chloride (TMAC), is investigated by a combination of NMR spectroscopic techniques and quantum chemical calculations. Chemical shift and nuclear quadrupolar interaction parameters have been measured for 35Cl, 1H/2H, and 15N/14N. These parameters have also been calculated as a function of the hydrogen position in the N\u2022\u2022\u2022H\u2022\u2022\u2022Cl fragment. Overall, the measured parameters are consistent with a structure in which the hydrogen is completely transferred to the nitrogen (i.e., N\u2013H\u2022\u2022\u2022Cl). The high hydrogen chemical shift (10.9 ppm by 2H CP/MAS) and relatively small deuterium quadrupolar coupling constant (127 kHz) indicate a moderately strong N\u2013H\u2022\u2022\u2022Cl hydrogen bond. A pronounced deuterium isotope effect on the 35Cl quadrupolar coupling constant is observed.Peer reviewed: YesNRC publication: Ye

A New Phase Shifting Technique for Deep UV Excimer Laser Based Lithography

This paper reports simulation and experimental details of a novel phase shifting technique based o laser interferometry. Phase shifting is one of the most promising techniques for the fabrication of high density DRAM's. In recent years many kinds of phase shifting methods have been proposed to extend the resolution limit and contrast of image patterns. These techniques however, have several problems that result from the phase shift elements on the mask, especially when applied to UV excimer laser illumination. A new technique will be described that is based on a one-layered reticle which is used as both a reflective and transmissive mask, irradiated from both the front and the back sides. A combination of both off-axis illumination, as well as phase shift are used in this method. Both the relative path length of the two beams as well as their amplitude can be manipulated in such a way that near 100% contrast can be achieved in the final image. Experimental as well as simulation data are used to demonstrate this new method.National Science Foundatio