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The low temperature properties of a wide range of many-fermion systems are well understood within the framework of Landau's theory of Fermi liquids. The low-energy physics of these systems is governed by interacting fermionic quasiparticles with momenta and energies near a Fermi surface in momentum space. Nonequilibrium properties are described by a kinetic equation for the distribution function for quasiparticles proposed by Landau. Quasiparticle interactions with other quasiparticles, phonons or impurities lead to internal forces acting on a distribution of nonequilibrium quasiparticles, as well as collision processes that ultimately limit the transport of mass, heat, charge and magnetization, as well as limit the coherence times of quasiparticles. For Fermi liquids that are close to a second order phase transition, e.g. Fermi liquids that undergo a superfluid transition, \emph{incipient} Cooper pairs - long-lived fluctuations of the ordered phase - provide a new channel for scattering quasiparticles, as well as corrections to internal forces acting on the distribution of nonequilibrium quasiparticles. We develop the theory of quasiparticle transport for Fermi liquids in the vicinity of a BCS-type superfluid transition starting from Keldysh's field theory for non-equilibrium, strongly interacting fermions. The leading corrections to Fermi liquid theory for non-equilibrium quasiparticle transport near a Cooper instability arise from the virtual emission and absorption of incipient Cooper pairs. Our theory is applicable to quasiparticle transport in superconductors, nuclear matter and the low temperature phases of liquid $^3$He. As an implementation of the theory we calculate the pairing fluctuation corrections to the attenuation of zero sound in liquid $^3$He near the superfluid transition and demonstrate quantitative agreement with experimental results., Comment: 22 pages, 8 Figures

Additional file 1. ToF-SIMS characterization of PEGylated biotin-conjugated PLGA nanofibers. Figure S1. Static cell-capture efficiencies of HCT116, MCF7, PC9, HepG2, Huh7, HeLa, and THP1 cell lines on random PLGA nanofiber arrays. HCT116, MCF7: EpCAM-positive cancer cell lines; HeLa, THP1: EpCAM-negative cancer cell lines. Figure S2. Three-dimensional representations of AFM topographic images and root mean square average roughnesses (Rrms) of a random and b aligned PLGA nanofiber arrays. Figure S3. a Cell viability tests for MCF7 cells captured on the control (tissue culture polystyrene, TCPS) and through on-chip (random PLGA nanofiber arrays) and off-chip cell collection (MCF7 cells released from random PLGA nanofiber arrays using the air foam technology). Released cells were washed twice with PBS and incubated for 24 h. Viability was assayed through the fluorescence live/dead staining result, which showed calcein AM (green) for live cells and Eth-1 (red) for dead cells (N = 3). b Live/dead staining image of off-chip cell collection (incubated on TCPS for 3 h).

The additive manufacturing technologies are fast-developing industrial sector and, potentially, a ground-breaking technology. They have many advantages such as the saving of resources and energy efficiency. However, the full exploitation of 3D printing technology for ceramic materials is currently limited; a lot of research is being conducted in this area. A promising solution seems to be geopolymers, but its application requires a better understanding of the behaviour this group of materials. This article analyses the influence of microstructure on mechanical properties whilst taking the production method into consideration. The paper is based on comparative analysis – the investigation is focused on the influence of material structure on the mechanical properties and fracture mechanism of these kinds of composites, including those reinforced with different kind of fibres. As a raw material for the matrix, fly ash from the Skawina coal power plant (located in: Skawina, Lesser Poland, Poland) was used. The investigation was made by SEM analysis. The results show that the microstructural analysis did not sufficiently explain the underlying reasons for the observed differences in the mechanical properties of the composites.

This work theoretically and experimentally demonstrates one hundred-watt and near single-mode of the 1018 nm ytterbium-doped fiber laser (YDFL). Amplified spontaneous emission effect in YDFL can be suppressed, which agrees with the simulations.

A novel self-aligned vertical electrostatic combdrives actuator has been developed and demonstrated, which enhances the capabilities and applications of high aspect ratio silicon-on-insulator microelectromechanical systems (SOI-MEMS) by enabling additional independent degrees of freedom of operation: both upward and downward vertical pistoning motion as well as bi-directional rotation. The present method utilizes four aligned masks greatly simplifying the existing SOI-MEMS fabrication methods for manufacturing high performance scanning micromirrors. Results from the micromirror device for the novel vertical combdrives show that a mechanical tilt angle of ±1° at 100 Vdc was achieved for a 450 µm diameter micromirror. The scanning micromirror can scan a large angle 62° at the resonance frequency of 10.46 kHz with a sinusoidal voltage input of 60 V in amplitude.

A compact variable optical attenuator (VOA) driving by thermal actuating principle with dual shutters for single mode fibers is developed. The fabricated thermal actuator array is capable of achieving larger displacement with low applied voltage than traditional thermal actuator array. The designed dual shutters can be driven independently or simultaneously, which increase the accurate tuning range and decrease working voltage for variable optical attenuator. The device is fabricated using MEMS-SOI fabrication technology, which greatly simplifies the traditional surface micromachining technology and increases its corresponding reliability. The newly designed thermal actuator array is capable of traveling 20 μm distance with less than 5 V applied voltage for VOA application. The insertion loss of the fabricated VOA is below 1.5 dB. The initial return loss and working return loss is about 50 and 40 dB, respectively. Experimental results indicated that the response time is below 4 ms and maximum attenuation range is about 40 and 45 dB at 1550 and 1310 nm, respectively. The working voltage and temperature of the designed VOA is under 5 V and 550 K, respectively.

A photonic device compatible low temperature process that is suitable for fabricating tunable Fabry–Perot filter is proposed in this paper [1] . The advantages of the presented process consist of (1) materials used in this process are compatible with existing optical or IC process; (2) process and detected spectra are not limited by different substrates. Experimental results of the manufactured tunable Fabry–Perot filter indicated that the full-width-half-maximum (FWHM) is closed to 1.3 nm and the measurement of reflectance of distributed Bragg reflectors is up to 99%. Note that within the 10 nm experimental tuning range, the FWHM is kept close to 1.3 nm with tuning voltage from 0 to 30 V. The experimental results showed that the presented process has potential to apply to wavelength division multiplexing (WDM) specifications of optical telecommunication. In particular, the process would also be integrated to fabricate tunable VCSEL processes.

We investigate the solar-system constraint on the f(R) theory of modified gravity with chameleon mechanism, where f(R) represents the deviation from general relativity in the gravity action. We obtain a stringent bound to a general, non-constant deviation function f(R): -10^{-15} < df/dR < 0 when R ~ 3*10^5*H0^2, and a loose bound: 0 < R*d(df/dR)/dR < 2/5 when R > 3*10^5*H0^2, by requiring the thin-shell condition in the solar system, particularly in the atmosphere of the Earth. These bounds can be conveniently utilized to test the f(R) models with given functional forms of f(R) and to obtain the constraints on the parameters therein. For demonstration we apply these bounds to several widely considered f(R) models. (H0: Hubble constant), 12 pages