Topological Excitation in Skyrme Theory

Based on the $\phi$-mapping topological current theory and the decomposition of gauge potential theory, we investigate knotted vortex lines and monopoles in Skyrme theory and simply discuss the branch processes (splitting, merging and intersection) during the evolution of the monopoles.Comment: 10 pages, 0 figure

The Design and Research of a New Low Cobalt-molybdenum Niobium-containing Ni-base Superalloy for 700 ̊C Advanced Ultra-supercritical Power Plants

AbstractA new Ni-base Nb-containing supealloy of low Co-Mo, Ni-24Cr-16(Co+Mo+W)-4.5(Nb+Ti+Al)-0.03C (wt. %), was designed for 700°C advanced ultra-super-critical power plant application, and the boiler superheater/reheater tubes were successfully manufactured. The alloy design was conducted by thermodynamics and dynamics calculation using Thermal-Calc and JmatPro commercial software. The microstructural stability of the new alloy was evaluated by FESEM and TEM. The mechanical properties, such as microhardness and impact toughness at room temperature, were also tested. The calculation results show that molybdenum promotes the formation of σ and μ phase obviously and cobalt promotes the formation of η, σ, and μ simultaneously. In addition, high molybdenum content will decrease the flue gas ash corrosion resistance and cobalt is a kind of strategic resource in the world. Therefore, the concept of “low Co-Mo Ni-base superalloy” was determined. The implementation of “Low Co-Mo” can reduce cost, restrain the formation of harmful phases as well as ensure good oxidation/corrosion resistance on the basis of high Cr content. To optimize the new alloy, both the combined solid solution strengthening of Cr-Co-Mo-W and the precipitation strengthening elements Nb, Ti and Al are adopted, because Nb is a good γ’-strengthening element in combination with Ti and Al for Ni-base superalloy. The experimental results of SEM and TEM show that no harmful phases precipitate after 1000 h-aging at 760°C and 800°C, and the γ′ coarsening rate is low, which reveals a good microstructure stability of this new alloy

Aroma Evaluation of Young Chinese Merlot Wines with Denomination of Origin

Merlot wines from four premium wine-producing districts in China were analysed for their volatilecomposition and sensory properties. Fifty-seven aroma compounds were quantified by SPME-GC-MSOAVanalysis, which showed that thirty of these compounds were active on the basis of their odour active value(OAV). According to the aroma descriptions of eleven impact odorants in all the sample wines, the collectivearoma characteristics of Chinese Merlot red wine are complex. Its main flavour is that of some tropical andtemperate fruits, such as banana, pineapple, green apple, pear and strawberry, along with a lactic flavourfrom the malolactic fermentation. It also has some traits of processed fruits, Muscat and floral pollen flavour.Moreover, different districts gave Merlot wine distinct characters. Changli wine had a higher intensity andcomplexity of global aroma, a strong fruity aroma, and an obvious nuance of lactic and nut traits. Thesine from Helanshan had weak fusel flavour and some lemon fruity flavour. Shacheng wine had weak fuselflavour, along with green grass and some fruity flavour of raspberry and violet. Manasi wine had the odourof unpleasant fatty acids and phenol due to its high content of fatty acids and volatile phenol. The sensoryanalysis confirmed the aroma prediction from the active odorants of the sample wines. Changli wine hadthe highest sensory scores, while Manasi wine had the worst evaluation of aroma, taste and harmony. Theresults suggest that the Merlot variety is more suitable for planting in Changli than in the Manasi region

The Effect of Ultrasonic Energy on Joint Characterization in Ultrasonic Spot Welding Multilayer Tabs Used in Lithium-ion Battery Manufacturing

Lithium-ion battery for electric vehicles contains a large number of battery tabs with multiple and thin sheets. Dissimilar metals are often used for different electrodes, for example, the copper and nickel are often used for negative electrode and the aluminum is often used for positive electrode. Meanwhile the thickness of metal sheets are various at different locations. Ultrasonic spot welding is very capable of welding similar and dissimilar combinations. However, there are less heat generation and plastic deformation in the bottom interfaces where ultrasonic energy is difficult to reach. This will result in the unbonded region occurrence caused by ultrasonic energy attenuation. In this work, experimental investigation was conducted to identify the effect of ultrasonic energy on joint characterization in ultrasonic welding multiple tabs by comparing the plastic deformation in different layers and various joint interfaces. Two sonotrodes with different knurl size were used to produce the welding energy for the tabs joining. Samples were cross-sectioned along vibration direction to obtain hardness profiles and metallographic maps. The hardness profile can be used to identify the changes of grain morphology. Hardness and grain size changes in different layers were also studied to reflect how ultrasonic energy decrease from top to bottom in battery tabs. Thereby, the relationship between material attributes and ultrasonic energy loss was established based on the experimental results

Evaluation of the Mechanical Properties of Germanium-on-Insulator (GeOI) Films by Raman Spectroscopy and Nanoindentation

Germanium-on-insulator (GeOI) films fabricated using the Smart Cut™ wafer bonding and film exfoliation technology were investigated for the mechanical properties and induced phase transformations by using nanoindentation and Raman spectroscopy experiments. The hardness and modulus results of the GeOI films are significantly different from the literature published Silicon-on-Insulator and bulk germanium results. The GeOI films are softer and more flexible as compared to bulk Ge hardness and stiffness properties. The Raman spectroscopy of the spherical indents indicates bands of metastable Ge phases @ 220 cm−1, 195 cm−1, and 184 cm−1 wavenumbers. Our results demonstrate that a spherical indenter impacted a wider area of contact and produced GeOI indented surfaces free of cracks and fracture. The spherical indenter tip kept the Ge top layer intact when compared to the Berkovich indenter tip during penetration. In contrast, the Berkovich indenter tip developed excessive fracture that resulted in displacing the Ge top layer sideways and exposed the Si substrate underneath revealing Raman spectra bands of metastable Si phases @ 350 cm−1, 399 cm−1, and 430 cm−1

Superconductivity and non-metallicity induced by doping the topological insulators Bi2Se3 and Bi2Te3

We show that by Ca-doping the Bi2Se3 topological insulator, the Fermi level can be fine tuned to fall inside the band gap and therefore suppress the bulk conductivity. Non-metallic Bi2Se3 crystals are obtained. On the other hand, the Bi2Se3 topological insulator can also be induced to become a bulk superconductor, with Tc ~ 3.8 K, by copper intercalation in the van der Waals gaps between the Bi2Se3 layers. Likewise, an as-grown crystal of metallic Bi2Te3 can be turned into a non-metallic crystal by slight variation of the Te content. The Bi2Te3 topological insulator shows small amounts of superconductivity with Tc ~ 5.5 K when reacted with Pd to form materials of the type PdxBi2Te3

Global analysis of regulatory divergence in the evolution of mouse alternative polyadenylation

Alternative polyadenylation (APA), which is regulated by both cis-elements and trans-factors, plays an important role in post-transcriptional regulation of eukaryotic gene expression. However, comparing to the extensively studied transcription and alternative splicing, the extent of APA divergence during evolution and the relative cis- and trans-contribution remain largely unexplored. To directly address these questions for the first time in mammals, by using deep sequencing-based methods, we measured APA divergence between C57BL/6J and SPRET/EiJ mouse strains as well as allele-specific APA pattern in their F1 hybrids. Among the 24,721 polyadenylation sites (pAs) from 7,271 genes expressing multiple pAs, we identified 3,747 pAs showing significant divergence between the two strains. After integrating the allele-specific data from F1 hybrids, we demonstrated that these events could be predominately attributed to cis-regulatory effects. Further systematic sequence analysis of the regions in proximity to cis-divergent pAs revealed that the local RNA secondary structure and a poly(U) tract in the upstream region could negatively modulate the pAs usage

Inflationary Attractor in Braneworld Scenario

We demonstrate the attractor behavior of inflation driven by a scalar field or a tachyon field in the context of recently proposed four-dimensional effective gravity induced on the world-volume of a three-brane in five-dimensional Einstein gravity, and we obtain a set of exact inflationary solutions. Phase portraits indicate that an initial kinetic term decays rapidly and it does not prevent the onset of inflation. The trajectories more rapidly reach the slow-roll curve than in the standard cosmology.Comment: 7 pages, 8 figures, RevTeX, to appear in Phys. Rev. D69 (2004

Quantum key distribution for d-level systems with generalized Bell states

Using the generalized Bell states and controlled not gates, we introduce an enatanglement-based quantum key distribution (QKD) of d-level states (qudits). In case of eavesdropping, Eve's information gain is zero and a quantum error rate of (d-1)/d is introduced in Bob's received qudits, so that for large d, comparison of only a tiny fraction of received qudits with the sent ones can detect the presence of Eve.Comment: 8 pages, 3 figures, REVTEX, references added, extensive revision, to appear in Phys. Rev.

Spinor Field Realizations of Non-critical W2,sW_{2,s} Strings

In this paper, we construct the nilpotent Becchi-Rouet-Stora-Tyutin($BRST$) charges of spinor non-critical $W_{2,s}$ strings. The cases of $s=3,4$ are discussed in detail, and spinor realization for $s=4$ is given explicitly. The $BRST$ charges are graded.Comment: 9 pages, no figure