Micro-alloying of yttrium in Zr-based bulk metallic glasses

AbstractThe effect of yttrium addition on the glass-forming ability (GFA) and mechanical properties of the Zr-based (Zr0.525Al0.1Ti0.05Cu0.179Ni0.146)100−x Yx and (Zr0.55Al0.15Ni0.1Cu0.2)100−x Yx (x=0, 0.2, 0.4 0.6, 1, 2) alloys was studied. Micro-alloying of 0.6% yttrium enhances the room temperature ductility as well as the GFA of the Zr-based alloys. The mechanism of enhancing the GFA and room temperature ductility was analyzed. It is indicated that proper yttrium addition stabilizes the undercooled liquid by means of forming lots of ordered clusters, thus improving the GFA and the room temperature ductility

Long time and Painlev\'{e}-type asymptotics for the defocusing Hirota equation with finite density initial data

In this work, we consider the Cauchy problem for the defocusing Hirota equation with a nonzero background \begin{align} \begin{cases} iq_{t}+\alpha\left[q_{xx}-2\left(\left\vert q\right\vert^{2}-1\right)q\right]+i\beta\left(q_{xxx}-6\left\vert q\right\vert^{2}q_{x}\right)=0,\quad (x,t)\in \mathbb{R}\times(0,+\infty),\\ q(x,0)=q_{0}(x),\qquad \underset{x\rightarrow\pm\infty 1}{\lim} q_{0}(x)=\pm 1, \qquad q_{0}\mp 1\in H^{4,4}(\mathbb{R}). \end{cases} \nonumber \end{align} According to the Riemann-Hilbert problem representation of the Cauchy problem and the $\bar{\partial}$ generalization of the nonlinear steepest descent method, we find different long time asymptotics types for the defocusing Hirota equation in oscillating region and transition region, respectively. For the oscillating region $\xi<-8$, four phase points appear on the jump contour $\mathbb{R}$, which arrives at an asymptotic expansion,given by \begin{align} q(x,t)=-1+t^{-1/2}h+O(t^{-3/4}).\nonumber \end{align} It consists of three terms. The first term $-1$ is leading term representing a nonzero background, the second term $t^{-1/2}h$ originates from the continuous spectrum and the third term $O(t^{-3/4})$ is the error term due to pure $\bar{\partial}$-RH problem. For the transition region $\vert\xi+8\vert t^{2/3}<C$, three phase points raise on the jump contour $\mathbb{R}$. Painlev\'{e} asymptotics expansion is obtained \begin{align} q(x,t)=-1-(\frac{15}{4}t)^{-1/3}\varrho+O(t^{-1/2}),\nonumber \end{align} in which the leading term is a solution to the Painlev\'{e} II equation, the last term is a residual error being from pure $\bar{\partial}$-RH problem and parabolic cylinder model

Anomalous thermoelectric transport of Dirac particles in graphene

We report a thermoelectric study of graphene in both zero and applied magnetic fields. As a direct consequence of the linear dispersion of massless particles, we find that the Seebeck coefficient Sxx diverges with 1 /, where n2D is the carrier density. We observe a very large Nernst signal Sxy (~ 50 uV/K at 8 T) at the Dirac point, and an oscillatory dependence of both Sxx and Sxy on n2D at low temperatures. Our results underscore the anomalous thermoelectric transport in graphene, which may be used as a highly sensitive probe for impurity bands near the Dirac point

AGE-RELATED SARCOPENIA: AN ELECTROMYOGRAPHIC AND MECHANOMYOGRAPHYIC STUDY

The purpose of this study was to investigate the effects of age-related sarcopenia on muscle mass, relative muscle strength/power performance in the lower limbs, and the responses of electromyography (EMG) and mechanomyography (MMG) on the activation patterns of motor units under leg extension muscle power performance in the elderly. Subjects were healthy old (n=10, 64.5 ± 4.5 yrs) and young (n=10, 22.6 ± 2.8yrs) people. All subjects performed quadriceps maximal voluntary contraction (MVC) and fastest speed leg extension with different levels (75%, 60%, 45% 1RM), and 45% fatigue test to all-outThe results indicate the declines of muscle mass, neuromuscular performance and changes of MU activation patterns may result from age-related sarcopenia, and the age affects muscle power more than muscle strength

Redetermined structure of oxaline: absolute configuration using Cu Kα radiation

In the title compound, C24H25N5O4, the stereogenic C atom bonded to three N atoms and one C atom has an S configuration and its directly bonded neighbour has an R configuration. An intra­molecular N—H⋯O hydrogen bond supports the near coplanarity of the two C3N2-five-membered rings [dihedral angle = 5.64 (10)°]. In the crystal, mol­ecules are linked by N—H⋯N hydrogen bonds, forming a C(8) chain propagating in [001]. The chains are connected by C—H⋯O inter­actions, generating a three-dimensional network. The previous study [Nagel et al. (1974 ▶). Chem. Commun. pp. 1021–1022] did not establish the absolute structure and no atomic coordinates were published or deposited

Time-resolved boson sampling with photons of different colors

Interference of multiple photons via a linear-optical network has profound applications for quantum foundation, quantum metrology and quantum computation. Particularly, a boson sampling experiment with a moderate number of photons becomes intractable even for the most powerful classical computers, and will lead to "quantum supremacy". Scaling up from small-scale experiments requires highly indistinguishable single photons, which may be prohibited for many physical systems. Here we experimentally demonstrate a time-resolved version of boson sampling by using photons not overlapping in their frequency spectra from three atomic-ensemble quantum memories. Time-resolved measurement enables us to observe nonclassical multiphoton correlation landscapes. An average fidelity over several interferometer configurations is measured to be 0.936(13), which is mainly limited by high-order events. Symmetries in the landscapes are identified to reflect symmetries of the optical network. Our work thus provides a route towards quantum supremacy with distinguishable photons.Comment: 5 pages, 3 figures, 1 tabl

Genetically engineered pre-microRNA-34a prodrug suppresses orthotopic osteosarcoma xenograft tumor growth via the induction of apoptosis and cell cycle arrest.

Osteosarcoma (OS) is the most common primary malignant bone tumor in children, and microRNA-34a (miR-34a) replacement therapy represents a new treatment strategy. This study was to define the effectiveness and safety profiles of a novel bioengineered miR-34a prodrug in orthotopic OS xenograft tumor mouse model. Highly purified pre-miR-34a prodrug significantly inhibited the proliferation of human 143B and MG-63 cells in a dose dependent manner and to much greater degrees than controls, which was attributed to induction of apoptosis and G2 cell cycle arrest. Inhibition of OS cell growth and invasion were associated with release of high levels of mature miR-34a from pre-miR-34a prodrug and consequently reduction of protein levels of many miR-34a target genes including SIRT1, BCL2, c-MET, and CDK6. Furthermore, intravenous administration of in vivo-jetPEI formulated miR-34a prodrug significantly reduced OS tumor growth in orthotopic xenograft mouse models. In addition, mouse blood chemistry profiles indicated that therapeutic doses of bioengineered miR-34a prodrug were well tolerated in these animals. The results demonstrated that bioengineered miR-34a prodrug was effective to control OS tumor growth which involved the induction of apoptosis and cell cycle arrest, supporting the development of bioengineered RNAs as a novel class of large molecule therapeutic agents