New Terms for the Compact Form of Electroweak Chiral Lagrangian

The compact form of the electroweak chiral Lagrangian is a reformulation of its original form and is expressed in terms of chiral rotated electroweak gauge fields, which is crucial for relating the information of underlying theories to the coefficients of the low-energy effective Lagrangian. However the compact form obtained in previous works is not complete. In this letter we add several new chiral invariant terms to it and discuss the contributions of these terms to the original electroweak chiral Lagrangian.Comment: 3 pages, references adde

3D meso-scale modelling of concrete material in spall tests

Tensile strength is one of the key factors of concrete material that need be accurately defined in analysis of concrete structures subjected to high-speed impact loads. Dynamic tensile strength of concrete material is usually obtained by conducting laboratory tests such as direct tensile test, Brazilian splitting test and spall test. Concrete is a heterogeneous material with different components, but is conventionally assumed to be homogeneous, i.e., cement mortar only, in most previous experimental or numerical studies. The aggregates in concrete material are usually neglected owing to testing limitation and numerical simplification. It has been well acknowledged that neglecting coarse aggregates might not necessarily give accurate concrete dynamic material properties. In the present study, a 3D meso-scale model of concrete specimen with consideration of cement mortar and aggregates is developed to simulate spall tests and investigate the behaviour of concrete material under high strain rate. The commercial software LS-DYNA is used to perform the numerical simulations of spall tests. The mesh size sensitivity is examined by conducting mesh convergence tests. The reliability of the numerical model in simulating the spall tests is verified by comparing the numerical results with the experimental data from the literature. The influence of coarse aggregates on the experimental test results is studied. The wave attenuation in concrete specimen is analysed, and empirical equations are proposed for quick assessment of the test data to determine the true dynamic tensile strength of concrete material. The contributions of aggregates to dynamic strength in spall tests are quantified for modifying the test results based on mortar material in the literature

Removal mechanisms and plant species selection by bioaccumulative factors in surface flow constructed wetlands (CWs): In the case of triclosan

© 2015 Elsevier B.V. Plants can bioaccumulate triclosan and bond with microbes and sediments in constructed wetlands (CWs) as well. However, little is known regarding the species-specific removal mechanism of CWs components and the selection of suitable wetland plant species for triclosan disposal. In this work, the use of bioaccumulation factors (BAFs) and biota to sediment accumulation factors (BSAFs) for choosing the best triclosan removal plant species was studied in laboratory-scale CWs. By the end of the experiment, over 80% of triclosan was removed and a specie-effect distribution was revealed in CWs with emergent, submerged and floating plants. By mass balance calculation, negative correlation between triclosan concentration in plants and degradation process was observed. The significant correlations between Log BSAFs values and triclosan concentration in plants or degradation contribution made it possible and reasonable in wetland plants selection. Introductions on plant species were provided considering the target removal process or regulation method. This work provided new information on plant species selection in CWs for triclosan removal or its emergency remediation by using bioaccumulative factors

On the effectiveness of rotational friction hinge damper to control responses of multi-span simply supported bridge to non-uniform ground motions

Base isolation techniques have been extensively used to improve the seismic performance of the bridge structures. The decoupling of the bridge decks from the piers and abutments using rubber isolator could result in significant reduction in seismic forces transmitted to the bridge substructures. However, the isolation devices could also increase the deck displacement and thus enhance the possibility of pounding and unseating damage of bridge decks. Moreover, previous investigations have shown that pounding and unseating damages on isolated bridges exacerbate due to the spatial variation in earthquake ground motions. Recent earthquakes revealed that isolation bearing could also be damaged due to the excessive movements of decks during large earthquake events. This study proposes the use of rotational friction hinge dampers to mitigate the damages that could be induced by large displacement of bridge decks, particularly focusing on pounding and unseating damages and bearing damages. The device is capable of providing large hysteretic damping and the cost of installing the devices is relatively economical. This article presents numerical investigations on the effectiveness of these devices on a typical Nepalese simply supported bridge subjected to spatially varying ground motions. The results indicate that rotational friction hinge dampers are very effective in mitigating the relative displacement and pounding force, as well as controlling the bearing deformation and pier drift. It is also revealed that the effectiveness of the device is not significantly affected by small changes in the slip forces; thus, small variations in the optimum slip forces during the lifetime of the bridge do not warrant any adjustment or replacement of the device

Intrinsic and Extrinsic Performance Limits of Graphene Devices on SiO2

The linear dispersion relation in graphene[1,2] gives rise to a surprising prediction: the resistivity due to isotropic scatterers (e.g. white-noise disorder[3] or phonons[4-8]) is independent of carrier density n. Here we show that acoustic phonon scattering[4-6] is indeed independent of n, and places an intrinsic limit on the resistivity in graphene of only 30 Ohm at room temperature (RT). At a technologically-relevant carrier density of 10^12 cm^-2, the mean free path for electron-acoustic phonon scattering is >2 microns, and the intrinsic mobility limit is 2x10^5 cm^2/Vs, exceeding the highest known inorganic semiconductor (InSb, ~7.7x10^4 cm^2/Vs[9]) and semiconducting carbon nanotubes (~1x10^5 cm^2/Vs[10]). We also show that extrinsic scattering by surface phonons of the SiO2 substrate[11,12] adds a strong temperature dependent resistivity above ~200 K[8], limiting the RT mobility to ~4x10^4 cm^2/Vs, pointing out the importance of substrate choice for graphene devices[13].Comment: 16 pages, 3 figure

Tripartite interactions between two phase qubits and a resonant cavity

The creation and manipulation of multipartite entangled states is important for advancements in quantum computation and communication, and for testing our fundamental understanding of quantum mechanics and precision measurements. Multipartite entanglement has been achieved by use of various forms of quantum bits (qubits), such as trapped ions, photons, and atoms passing through microwave cavities. Quantum systems based on superconducting circuits have been used to control pair-wise interactions of qubits, either directly, through a quantum bus, or via controllable coupling. Here, we describe the first demonstration of coherent interactions of three directly coupled superconducting quantum systems, two phase qubits and a resonant cavity. We introduce a simple Bloch-sphere-like representation to help one visualize the unitary evolution of this tripartite system as it shares a single microwave photon. With careful control and timing of the initial conditions, this leads to a protocol for creating a rich variety of entangled states. Experimentally, we provide evidence for the deterministic evolution from a simple product state, through a tripartite W-state, into a bipartite Bell-state. These experiments are another step towards deterministically generating multipartite entanglement in superconducting systems with more than two qubits

Broadband random optoelectronic oscillator

[EN] Random scattering of light in transmission media has attracted a great deal of attention in the field of photonics over the past few decades. An optoelectronic oscillator (OEO) is a microwave photonic system offering unbeatable features for the generation of microwave oscillations with ultra-low phase noise. Here, we combine the unique features of random scattering and OEO technologies by proposing an OEO structure based on random distributed feedback. Thanks to the random distribution of Rayleigh scattering caused by inhomogeneities within the glass structure of the fiber, we demonstrate the generation of ultra-wideband (up to 40¿GHz from DC) random microwave signals in an open cavity OEO. The generated signals enjoy random characteristics, and their frequencies are not limited by a fixed cavity length figure. The proposed device has potential in many fields such as random bit generation, radar systems, electronic interference and countermeasures, and telecommunications.Thanks N. Shi and Y. Yang for comments and discussion. This work was supported by the National Key Research and Development Program of China under 2018YFB2201902 and the National Natural Science Foundation of China under 61925505. This work was also partly supported by the National Key Research and Development Program of China under 2018YFB2201901, 2018YFB2201903, and the National Natural Science Foundation of China under 61535012 and 61705217.Ge, Z.; Hao, T.; Capmany Francoy, J.; Li, W.; Zhu, N.; Li, M. (2020). Broadband random optoelectronic oscillator. Nature Communications. 11(1):1-8. https://doi.org/10.1038/s41467-020-19596-xS18111Feng, S., Kane, C., Lee, P. A. & Stone, A. D. Correlations and fluctuations of coherent wave transmission through disordered media. Phys. Rev. Lett. 61, 834 (1988).Wiersma, D. S. & Cavalieri, S. Light emission: a temperature-tunable random laser. Nature 414, 708 (2001).Wiersma, D. S. The physics and applications of random lasers. Nat. Phys. 4, 359 (2008).Turitsyn, S. K. et al. Random distributed feedback fibre laser. Nat. Photonics 4, 231–235 (2010).Babin, S. A., El-Taher, A. E., Harper, P., Podivilov, E. V. & Turitsyn, S. K. Tunable random fiber laser. Phys. Rev. A 84, 021805 (2011).Turitsyn, S. K. et al. Random distributed feedback fibre lasers. Phys. Rep. 542, 133–193 (2014).Barnoski, M., Rourke, M., Jensen, S. M. & Melville, R. T. Optical time domain reflectometer. Appl. Opt. 16, 2375–2379 (1977).Yao, X. S. & Maleki, L. Optoelectronic microwave oscillator. JOSA B 13, 1725–1735 (1996).Maleki, L. Sources: the optoelectronic oscillator. Nat. Photonics 5, 728 (2011).Yao, X. S. & Maleki, L. Multiloop optoelectronic oscillator. IEEE J. Quantum Electron 36, 79–84 (2000).Hao, T. et al. Breaking the limitation of mode building time in an optoelectronic oscillator. Nat. Commun. 9, 1839 (2018).Zhang, W. & Yao, J. Silicon photonic integrated optoelectronic oscillator for frequency-tunable microwave generation. J. Lightwave Technol. 36, 4655–4663 (2018).Hao, T. et al. Toward Monolithic Integration of OEOs: from systems to chips. J. Lightwave Technol. 36, 4565–4582 (2018).Zhang, J. & Yao, J. Parity-time–symmetric optoelectronic oscillator. Sci. Adv. 4, eaar6782 (2018).Liu, Y. et al. Observation of parity-time symmetry in microwave photonics. Light Sci. Appl. 7, 38 (2018).Nakazawa, M. Rayleigh backscattering theory for single-mode optical fibers. JOSA 73, 1175–1180 (1983).Hartog, A. & Gold, M. On the theory of backscattering in single-mode optical fibers. J. Lightwave Technol. 2, 76–82 (1984).Eickhoff, W., & Ulrich, R. Statistics of backscattering in single-mode fiber. In Optical Fiber Communication Conference. Optical Society of America (1981).Alekseev, A. E., Tezadov, Y. A. & Potapov, V. T. Statistical properties of backscattered semiconductor laser radiation with different degrees of coherence. Quantum Electron 42, 76–81 (2012).Gysel, P. & Staubli, R. K. Statistical properties of Rayleigh backscattering in single-mode fibers. J. Lightwave Technol. 8, 561–567 (1990).Staubli, R. K. & Gysel, P. Statistical properties of single-mode fiber rayleigh backscattered intensity and resulting detector current. IEEE Trans. Commun. 40, 1091–1097 (1992).Levy, E. C., Horowitz, M. & Menyuk, C. R. Modeling optoelectronic oscillators. JOSA B 26, 148–159 (2009).Yariv, A. Introduction to Optical Electronics 2nd edn. (Holt, Rinehart and Winston, New York, 1976).Aoki, Y., Tajima, K. & Mito, I. Input power limits of single-mode optical fibers due to stimulated Brillouin scattering in optical communication systems. J. Lightwave Technol. 6, 710–719 (1988).Song, H. J., Shimizu, N., Kukutsu, N., Nagatsuma, T. & Kado, Y. Microwave photonic noise source from microwave to sub-terahertz wave bands and its applications to noise characterization. IEEE Trans. Microw. Theory Tech. 56, 2989–2997 (2008).Chembo, Y. K., et al. Optoelectronic oscillators with time-delayed feedback. Rev. Mod. Phys. 91, 035006 (2019).Callan, K. E. et al. Broadband chaos generated by an optoelectronic oscillator. Phys. Rev. Lett. 104, 113901 (2010).Lavrov, R. et al. Electro-optic delay oscillator with nonlocal nonlinearity: Optical phase dynamics, chaos, and synchronization. Phys. Rev. E. 80, 026207 (2009).Wolf, A., Swift, J. B., Swinney, H. L. & Vastano, J. A. Determining Lyapunov exponents from a time series. Phys. D. 16, 285–317 (1985).Grassberger, P. & Procaccia, I. Characterization of strange attractors. Phys. Rev. Lett. 50, 346 (1983).Grassberger, P. & Procaccia, I. Measuring the strangeness of strange attractors. Phys. D. 9, 189–208 (1983).Romeira, B. et al. Broadband chaotic signals and breather oscillations in an optoelectronic oscillator incorporating a microwave photonic filter. J. Lightwave Technol. 32, 3933–3942 (2014)

Histone Acetylation-Mediated Regulation of the Hippo Pathway

The Hippo pathway is a signaling cascade recently found to play a key role in tumorigenesis therefore understanding the mechanisms that regulate it should open new opportunities for cancer treatment. Available data indicate that this pathway is controlled by signals from cell-cell junctions however the potential role of nuclear regulation has not yet been described. Here we set out to verify this possibility and define putative mechanism(s) by which it might occur. By using a luciferase reporter of the Hippo pathway, we measured the effects of different nuclear targeting drugs and found that chromatin-modifying agents, and to a lesser extent certain DNA damaging drugs, strongly induced activity of the reporter. This effect was not mediated by upstream core components (i.e. Mst, Lats) of the Hippo pathway, but through enhanced levels of the Hippo transducer TAZ. Investigation of the underlying mechanism led to the finding that cancer cell exposure to histone deacetylase inhibitors induced secretion of growth factors and cytokines, which in turn activate Akt and inhibit the GSK3 beta associated protein degradation complex in drug-affected as well as in their neighboring cells. Consequently, expression of EMT genes, cell migration and resistance to therapy were induced. These processes were suppressed by using pyrvinium, a recently described small molecule activator of the GSK 3 beta associated degradation complex. Overall, these findings shed light on a previously unrecognized phenomenon by which certain anti-cancer agents may paradoxically promote tumor progression by facilitating stabilization of the Hippo transducer TAZ and inducing cancer cell migration and resistance to therapy. Pharmacological targeting of the GSK3 beta associated degradation complex may thus represent a unique approach to treat cancer. © 2013 Basu et al

Determinant representations of scalar products for the open XXZ chain with non-diagonal boundary terms

With the help of the F-basis provided by the Drinfeld twist or factorizing F-matrix for the open XXZ spin chain with non-diagonal boundary terms, we obtain the determinant representations of the scalar products of Bethe states of the model.Comment: Latex file, 28 pages, based on the talk given by W. -L. Yang at Statphys 24, Cairns, Australia, 19-23 July, 201

Formation of artificial pores in nano-TiO2 photo-electrode films using acetylene-black for high-efficiency, dye-sensitized solar cells

Acetylene-black paste without a light scattering layer was applied to meso-porous TiO2 photo-electrode films with a crystalline framework, a low residual carbon, and a tunable morphological pore size. The thermal-treated TiO2 photo-electrode films had an increased acetylene-black concentration with an increase in artificial pores and a decrease in residual carbon. The performance of dye-sensitized solar cells (DSSCs) was enhanced by the use of the TiO2 photo-anode pastes at various acetylene-black concentrations. The photo-conversion efficiency of the DSSCs using TiO2 photo-electrode films with 1.5 wt% acetylene-black was enhanced from 7.98 (no acetylene-black) to 9.75% without the integration of a light-scattering layer.open5