Efficiency at maximum power output of an irreversible Carnot-like cycle with internally dissipative friction

We investigate the efficiency at maximum power of an irreversible Carnot engine performing finite-time cycles between two reservoirs at temperatures $T_h$ and $T_c$ $(T_c<T_h)$, taking into account of internally dissipative friction in two "adiabatic" processes. In the frictionless case, the efficiencies at maximum power output are retrieved to be situated between $\eta_{_C}/$ and $\eta_{_C}/(2-\eta_{_C})$, with $\eta_{_C}=1-T_c/{T_h}$ being the Carnot efficiency. The strong limits of the dissipations in the hot and cold isothermal processes lead to the result that the efficiency at maximum power output approaches the values of $\eta_{_C}/$ and $\eta_{_C}/(2-\eta_{_C})$, respectively. When dissipations of two isothermal and two adiabatic processes are symmetric, respectively, the efficiency at maximum power output is founded to be bounded between 0 and the Curzon-Ahlborn (CA) efficiency $1-\sqrt{1-\eta{_C}}$, and the the CA efficiency is achieved in the absence of internally dissipative friction

Compound memory networks for few-shot video classification

© Springer Nature Switzerland AG 2018. In this paper, we propose a new memory network structure for few-shot video classification by making the following contributions. First, we propose a compound memory network (CMN) structure under the key-value memory network paradigm, in which each key memory involves multiple constituent keys. These constituent keys work collaboratively for training, which enables the CMN to obtain an optimal video representation in a larger space. Second, we introduce a multi-saliency embedding algorithm which encodes a variable-length video sequence into a fixed-size matrix representation by discovering multiple saliencies of interest. For example, given a video of car auction, some people are interested in the car, while others are interested in the auction activities. Third, we design an abstract memory on top of the constituent keys. The abstract memory and constituent keys form a layered structure, which makes the CMN more efficient and capable of being scaled, while also retaining the representation capability of the multiple keys. We compare CMN with several state-of-the-art baselines on a new few-shot video classification dataset and show the effectiveness of our approach

Probing QCD critical point and induced gravitational wave by black hole physics

The Quantum Chromodynamics (QCD) phase diagram involves the behaviors of strongly interacting matter under extreme conditions and remains an important open problem. Based on the non-perturbative approach from the gauge/gravity duality, we construct a family of black holes that provide a dual description of the QCD phase diagram at finite chemical potential and temperature. The thermodynamic properties from the model are in good agreement with the state-of-the-art lattice simulations. We then predict the location of the critical endpoint and the first-order phase transition line. Moreover, we present the energy spectrum of the stochastic gravitational-wave background associated with the QCD first-order transition, which is found to be detected by IPTA and SKA, while by NANOGrav with less possibility

The Divergent Effects of Resilience Qualities and Resilience Support in Predicting Pre-Competition Anxiety and Championship Performance

Psychological resilience is vital to the development of sport talents. Qualitative research has consistently demonstrated that sport resilience encapsulates a mixed package of resilience qualities (reflecting positive traits and characteristics) and resilience support (reflecting perceived support and related resources). Ironically, sport resilience research adopting quantitative methods has been assessing resilience as a unidimensional construct, with little attention to the multi-facet nature of resilience and its effects on performance. In the present research, we tested a novel proposition that resilience qualities predict reduced pre-competition cognitive anxiety and contribute to performance more than resilience support. Across two samples of competitive table tennis players (Study 1: N = 196 competing at province level; Study 2: N = 106 competing at national level), we consistently found resilience qualities, rather than resilience support, predicted lower levels of pre-competition cognitive anxiety and superior performance at a national championship. Results also suggest that pre-competition cognitive anxiety mediated the relationship between resilience qualities and performance. The findings provide the first evidence supporting the divergent effects of resilience qualities and resilience support in predicting pre-competition anxiety and championship performance and call for the consideration of such a distinction when designing and delivering resilience programmes

Gravitational Waves and Primordial Black Hole Productions from Gluodynamics

We construct a holographic model describing the gluon sector of Yang-Millstheories at finite temperature in the non-perturbative regime. The equation ofstate as a function of temperature is in good accordance with the latticequantum chromodynamics (QCD) data. Moreover, the Polyakov loop and the gluoncondensation, which are proper order parameters to capture the deconfinementphase transition, also agree quantitatively well with the lattice QCD data. Weobtain a strong first-order confinement/deconfinement phase transition at$T_c=276.5\,\text{MeV}$ that is consistent with the lattice QCD prediction. Theresulting stochastic gravitational-wave backgrounds from thisconfinement/deconfinement phase transition are obtained with potentialdetectability in the International Pulsar Timing Array and Square KilometreArray in the near future when the associated productions of primordial blackholes (PBHs) saturate the current observational bounds on the PBH abundancesfrom the LIGO-Virgo-Collaboration O3 data.<br