93Nb knight shift and quadrupole coupling parameters in the orthorhombic β phase hydride and deuteride of niobium

The Knight shift tensor components and quadrupole coupling parameters of the ⁹³Nb NMR have been measured for the first time in the orthorhombic β phase hydride and deuteride of niobium. The isotropic component of the Knight shift tensor has the same value in the hydride phase as in the solid solution (α') phase at the same composition, indicating that no significant change in band structure details occurs as a consequence of the structural phase transition. Comparison of the measured asymmetry parameter of the quadrupole interaction with calculated values indicates that the probable Nb environment is that of the ordered NbH structure. Estimates of the activation energy for hydrogen (deuterium) diffusion are obtained from the temperature dependence of the linewidths of the spectrum features.     

Recoil corrections to magnetic moments of octet baryons in the MIT bag model

The presence of certain recoil corrections in the determination of baryon magnetic moments is described and taken into account for the octet members. Inclusion of these recoil corrections makes the MIT bag model, even in its zeroth-order version, very appealing, if the sum of many other corrections is not important by comparison.     

The temperature dependence of the elastic constants for highly oriented pyrolytic graphite determined by ultrasonic techniques

Sound velocities along the c-axis of highly oriented pyrolytic graphite between 4 and 325 K were measured with an ultrasonic pulse-echo phase-comparison method. The echo delay times were determined with an accuracy of 0.05 and 0.15%, respectively, for the longitudinal and transverse modes. The temperature dependence of the c-axis elastic constants C₃₃ and C₄₄ was deduced with the correction of thermal expansion. C₃₃ was found to decrease by 5.8% from 4 to 300 K and can be interpreted by a model based on the simple Lennard-Jones interlayer interaction. C₄₄ and its temperature variation are found to be strongly sample dependent.     

A short proof of a result of Pollak on Steiner minimal trees

The long-standing conjecture of Gilbert and Pollak states that for any set of n given points in the euclidean plane, the ratio of the length of a Steiner minimal tree and the length of a minimal (spanning) tree is at least $\text{3}\text{2}$. This conjecture was shown to be true for n = 3 by Gilbert and Pollak, and for n = 4 by Pollak. However, the proof for n = 4 by Pollak is sufficiently complicated that no generalization to any other value of n has been found. We use a different approach to give a very short proof for the n = 4 case. This approach also allows us to attack the n = 5 case, though the proof is no longer short (to be reported in a subsequent paper).     

Complete balanced Howell rotations for 8k+5 teams

Complete balanced Howell rotations are mathematical designs for highly structured paired-comparison experiments. They have been widely used in bridge tournaments, and many special cases are applicable to round-robin tournaments for all kinds of sports. In this paper we construct complete balanced Howell rotations of 8k + 5 teams, for 8k + 5 a prime power greater than 5. We also show that “table balanced” complete balanced Howell rotations for 8k + 5 teams do not exist unless 8k + 5 is the sum of two squares of integers.     

Liquid crystal alignment and pretilt angle generation on a photopolymer layer based on N-(phenyl)maleimide

A photopolymer based on N-(phenyl)maleimide was synthesized and the liquid crystal (LC) alignment effects of the photopolymer layer on homeotropic alignment were studied. Good LC alignment with UV exposure of PMI5CA (N-(phenyl)maleimide with a 5-carbon chain cinnamoyl group) was obtained. However, defective LC alignment was observed for PMI3CA (N-(phenyl)maleimide with a 3-carbon chain cinnamoyl group) and PMIF (N-(phenyl)maleimide including a fluoro-cinnamoyl group). Good LC alignment with UV exposure on the PMI5CA surface was observed with annealing temperature up to 150°C. It seems that the LC aligning ability of the photopolymer layers based on N-(phenyl)maleimide depends on the side chain length of the photopolymer.     

Elemental‐Sulfur‐Mediated Facile Synthesis of a Covalent Triazine Framework for High‐Performance Lithium–Sulfur Batteries

A covalent triazine framework (CTF) with embedded polymeric sulfur and a high sulfur content of 62 wt % was synthesized under catalyst‐ and solvent‐free reaction conditions from 1,4‐dicyanobenzene and elemental sulfur. Our synthetic approach introduces a new way of preparing CTFs under environmentally benign conditions by the direct utilization of elemental sulfur. The homogeneous sulfur distribution is due to the in situ formation of the framework structure, and chemical sulfur impregnation within the micropores of CTF effectively suppresses the dissolution of polysulfides into the electrolyte. Furthermore, the triazine framework facilitates electron and ion transport, which leads to a high‐performance lithium–sulfur battery.     

Improved conditions for fluorescent staining of proteins with 4,4′‐dianilino‐1,1′‐binaphthyl‐5,5′‐disulfonic acid in SDS‐PAGE

A simple and sensitive fluorescent staining method for the detection of proteins in SDS‐PAGE, namely IB (improved 4,4′‐dianilino‐1,1′‐binaphthyl‐5,5′‐disulfonic acid) stain, is described. Non‐covalent hydrophobic probe 4,4′‐dianilino‐1,1′‐binaphthyl‐5,5′‐disulfonic acid was applied as a fluorescent dye, which can bind to hydrophobic sites in proteins non‐specifically. As low as 1 ng of protein band can be detected briefly by 30 min washing followed by 15 min staining without the aiding of stop or destaining step. The sensitivity of the new presented protocol is similar to that of SYPRO Ruby, which has been widely accepted in proteomic research. Comparative analysis of the MS compatibility of IB stain and SYPRO Ruby stain allowed us to address that IB stain is compatible with the downstream of protein identification by PMF.