Graphite-metal composites Quarterly report no. 1, 1 Aug. - 1 Nov. 1965

Graphite-metal composites - hot pressing equipment modifications, hot pressing of calcined petroleum coke, and heterogeneity in density of niobium, hafnium, and molybdenum-graphite

Metal carbide-graphite composites

Tungsten used in NbC-C composites as low melting densification additive to improve composite properties and lower fabrication temperature

Metal Carbide-graphite Composites Quarterly Report, Aug. 1 - Oct. 31, 1966

Physical and mechanical properties of tantalum carbide and niobium carbide composite

Fabrication and Characterization of Metal Carbide-graphite Composites

Hot press fabrication effects on phase equilibrium and physical properties of refractory metal carbide-graphite composite

Nontriviality of Gauge-Higgs-Yukawa System and Renormalizability of Gauged NJL Model

In the leading order of a modified 1/Nc expansion, we show that a class of gauge-Higgs-Yukawa systems in four dimensions give non-trivial and well-defined theories in the continuum limit. The renormalized Yukawa coupling y and the quartic scalar coupling \lambda have to lie on a certain line in the (y,\lambda) plane and the line terminates at an upper bound. The gauged Nambu--Jona-Lasinio (NJL) model in the limit of its ultraviolet cutoff going to infinity, is shown to become equivalent to the gauge-Higgs-Yukawa system with the coupling constants just on that terminating point. This proves the renormalizability of the gauged NJL model in four dimensions. The effective potential for the gauged NJL model is calculated by using renormalization group technique and confirmed to be consistent with the previous result by Kondo, Tanabashi and Yamawaki obtained by the ladder Schwinger-Dyson equation.Comment: 32 pages, LaTeX, 3 Postscript Figures are included as uuencoded files (need `epsf.tex'), KUNS-1278, HE(TH) 94/10 / NIIG-DP-94-2. (Several corrections in the introduction and references.

Rab8a and Rab8b are essential for several apical transport pathways but insufficient for ciliogenesis

The small GTP-binding protein Rab8 is known to play an essential role in intracellular transport and cilia formation. We have previously demonstrated that Rab8a is required for localising apical markers in various organisms. Rab8a has a closely related isoform, Rab8b. To determine whether Rab8b can compensate for Rab8a, we generated Rab8b-knockout mice. Although the Rab8b-knockout mice did not display an overt phenotype, Rab8a and Rab8b double-knockout mice exhibited mislocalisation of apical markers and died earlier than Rab8a-knockout mice. The apical markers accumulated in three intracellular patterns in the double-knockout mice. However, the localisation of basolateral and/or dendritic markers of the double-knockout mice seemed normal. The morphology and the length of various primary and/or motile cilia, and the frequency of ciliated cells appeared to be identical in control and double-knockout mice. However, an additional knockdown of Rab10 in double-knockout cells greatly reduced the percentage of ciliated cells. Our results highlight the compensatory effect of Rab8a and Rab8b in apical transport, and the complexity of the apical transport process. In addition, neither Rab8a nor Rab8b are required for basolateral and/or dendritic transport. However, simultaneous loss of Rab8a and Rab8b has little effect on ciliogenesis, whereas additional loss of Rab10 greatly affects ciliogenesis

Pigmented coating resists thermal shock

Coating pigment composed of zinc oxide and potassium silicate resists the effects of thermal shock and long exposure to direct sunlight

Abrupt enhancement of non-centrosymmetry and appearance of the spin-triplet superconducting state in Li_2(Pd_{1-x}Pt_{x})_3B beyond x=0.8

We report synthesis, ^{195}Pt, ^{11}B and ^{7}Li NMR measurements, and first-principle band calculation for non-centrosymmetric superconductors Li_{2}(Pd_{1-x}Pt_{x})_{3}B (x=0, 0.2, 0.5, 0.8, 0.84, 0.9 and 1). For 0 \leq x \leq 0.8, the spin-lattice relaxation rate 1/T_1 shows a clear coherence peak just below T_c, decreasing exponentially at low temperature, and the Knight shift ^{195}K decreases below T_c. For x=0.9 and 1.0, in contrast, 1/T_1 shows no coherence peak but a T^3 variation and ^{195}K remains unchanged across T_c. These results indicate that the superconducting state changes drastically from a spin-singlet dominant to a spin-triplet dominant state at x=0.8. We find that the distortion of B(Pt,Pd)_6 increases abruptly above x=0.8, which leads to an abrupt enhancement of the asymmetric spin-orbit coupling as confirmed by band calculation. Such local structure distortion that enhances the extent of inversion-symmetry breaking is primarily responsible for the pairing symmetry evolution. The insight obtained here provides a new guideline for searching new NCS superconductors with large spin-triplet component.Comment: to appear in Phys. Rev. B (Rapid Commun.); contact the authors for high-resolution figure

Plasma-sprayed self-lubricating coatings

One of the most important criterion for acceptable commercial application of a multiple phase composition is uniformity and reproducibility. This means that the performance characteristics of the coat - e.g., its lubricating properties, bond strength to the substrate, and thermal properties - can be readily predicted to give a desired performance. The improvement of uniformity and reproducibility of the coats, the oxidation behavior at three temperature ranges, the effect of bond coat and the effect of preheat treatment as measured by adhesive strength tests, coating examination procedures, and physical property measurements were studied. The following modifications improved the uniformity and reproducibility: (1) changes and closer control in the particle size range of the raw materials used, (2) increasing the binder content from 3.2% to 4.1% (dried weight), and (3) analytical processing procedures using step by step checking to assure consistency