Contributions of hyperon-hyperon scattering to subthreshold cascade production in heavy ion collisions

Using a gauged flavor SU(3)-invariant hadronic Lagrangian, we calculate the cross sections for the strangeness-exchange reactions YY to N\Xi (Y=\Lambda, \Sigma) in the Born approximation. These cross sections are then used in the Relativistic Vlasov-Uehling-Uhlenbeck (RVUU) transport model to study \Xi production in Ar+KCl collisions at incident energy of 1.76A GeV and impact parameter b=3.5 fm. We find that including the contributions of hyperon-hyperon scattering channels strongly enhances the yield of \Xi, leading to the abundance ratio \Xi^{-}/(\Lambda+\Sigma^{0})=3.38E-3, which is essentially consistent with the recently measured value of $(5.6 \pm 1.2_{-1.7}^{+1.8})\times 10^{-3}$ by the HADES collaboration at GSI.Comment: 8 pages, 5 figure

Sub-Band Knowledge Distillation Framework for Speech Enhancement

In single-channel speech enhancement, methods based on full-band spectral features have been widely studied. However, only a few methods pay attention to non-full-band spectral features. In this paper, we explore a knowledge distillation framework based on sub-band spectral mapping for single-channel speech enhancement. Specifically, we divide the full frequency band into multiple sub-bands and pre-train an elite-level sub-band enhancement model (teacher model) for each sub-band. These teacher models are dedicated to processing their own sub-bands. Next, under the teacher models' guidance, we train a general sub-band enhancement model (student model) that works for all sub-bands. Without increasing the number of model parameters and computational complexity, the student model's performance is further improved. To evaluate our proposed method, we conducted a large number of experiments on an open-source data set. The final experimental results show that the guidance from the elite-level teacher models dramatically improves the student model's performance, which exceeds the full-band model by employing fewer parameters.Comment: Published in Interspeech 202

Geometric Effects of Horizontal Branching T-junction on Phase Separation of Refrigerant

Separation technology has been widely developed to improve the performance of thermodynamic cycles, such as refrigeration, heat pump and power cycle. As a promising separator, T-junction has attracted widespread attention, due to the characteristics of simple geometry, low cost and compact size. Previous researches on the phase separation of air-water and steam-water have indicated that the separation performance depends heavily on the T-junction geometry. Therefore, in this work, geometric effects on phase separation of refrigerant were experimentally studied with different configurations of branching T-junction. In this study, all of the T-junctions had horizontal inlet and outlet tubes. The internal diameter of inlet tube was fixed at 8.0 mm, and the diameter ratio of the branch to the inlet was set to be 0.75 and 1.0. Furthermore, three branch angles, 45°, 90° and 135°, were considered. More than 156 experimental runs were conducted using refrigerant R-600a with inlet mass flux and vapor quality being varied from 200 to 300 kg·m−2·s−1 and from 0.1 to 0.9, respectively. Meanwhile, the mass flux of the branch was regulated by keeping the mass flow ratios in three levels: 0.3, 0.5 and 0.7. Flow regimes prior to the T-junction were identified and characterized. Based on these generated data, phase separation performance was analyzed in terms of mass flow ratio under given inlet vapor quality and mass flux. Effects of diameter ratio and branch angle were also investigated. From the test results, it can be concluded that the outlet quality of branch is always higher than the inlet quality. The fraction of vapor extracted into the branch decreases with the increase of inlet vapor quality. Under the same experimental conditions, the higher the mass flow ratio is, the larger the vapor fraction, while the inlet mass flux has little influence on the phase separation of refrigerant. As for the geometric effects, more vapors usually prefer to flow into the branch with the smaller diameter, when the mass flow ratio is relatively large. For the effect of branch angle, at low vapor quality, vapor fraction for the angle 45° is lower than those for angle 90° and 135° under the mass flow ratio of 0.5 and 0.7

Simple Pose: Rethinking and Improving a Bottom-up Approach for Multi-Person Pose Estimation

We rethink a well-know bottom-up approach for multi-person pose estimation and propose an improved one. The improved approach surpasses the baseline significantly thanks to (1) an intuitional yet more sensible representation, which we refer to as body parts to encode the connection information between keypoints, (2) an improved stacked hourglass network with attention mechanisms, (3) a novel focal L2 loss which is dedicated to hard keypoint and keypoint association (body part) mining, and (4) a robust greedy keypoint assignment algorithm for grouping the detected keypoints into individual poses. Our approach not only works straightforwardly but also outperforms the baseline by about 15% in average precision and is comparable to the state of the art on the MS-COCO test-dev dataset. The code and pre-trained models are publicly available online.Comment: Accepted by AAAI 2020 (the Thirty-Fourth AAAI Conference on Artificial Intelligence

Intergovernmental Relationships in Costal Land Management

In order to decrease the degradation rate of magnesium (Mg) alloys for the potential orthopedic applications, manganese-calcium phosphate coatings were prepared on an Mg-Ca-Zn alloy in calcium phosphating solutions with different addition of Mn2+. Influence of Mn content on degradation behaviors of phosphate coatings in the simulated body fluid was investigated to obtain the optimum coating. With the increasing Mn addition, the corrosion resistance of the manganese-calcium phosphate coatings was gradually improved. The optimum coating prepared in solution containing 0.05 mol/L Mn2+ had a uniform and compact microstructure and was composed of MnHPO4 center dot 3H(2)O, CaHPO4 center dot 2H(2)O, and Ca-3 (PO4)(2). The electrochemical corrosion test in simulated body fluid revealed that polarization resistance of the optimum coating is 36273 Omega cm(2), which is about 11 times higher than that of phosphate coating without Mn addition. The optimum coating also showed the most stable surface structure and lowest hydrogen release in the immersion test in simulated body fluid

High temperature ferrimagnetic semiconductors by spin-dependent doping in high temperature antiferromagnets

To realize room temperature ferromagnetic (FM) semiconductors is still a challenge in spintronics. Many antiferromagnetic (AFM) insulators and semiconductors with high Neel temperature $T_N$ are obtained in experiments, such as LaFeO$_3$, BiFeO$_3$, etc. High concentrations of magnetic impurities can be doped into these AFM materials, but AFM state with very tiny net magnetic moments was obtained in experiments, because the magnetic impurities were equally doped into the spin up and down sublattices of the AFM materials. Here, we propose that the effective magnetic field provided by a FM substrate could guarantee the spin-dependent doping in AFM materials, where the doped magnetic impurities prefer one sublattice of spins, and the ferrimagnetic (FIM) materials are obtained. To demonstrate this proposal, we study the Mn-doped AFM insulator LaFeO$_3$ with FM substrate of Fe metal by the density functional theory (DFT) calculations. It is shown that the doped magnetic Mn impurities prefer to occupy one sublattice of AFM insulator, and introduce large magnetic moments in La(Fe,Mn)O$_3$. For the AFM insulator LaFeO$_3$ with high $T_N$ = 740 K, several FIM semiconductors with high Curie temperature $T_C >$ 300 K and the band gap less than 2 eV are obtained by DFT calculations, when 1/8 or 1/4 Fe atoms in LaFeO$_3$ are replaced by the other 3d, 4d transition metal elements. The large magneto-optical Kerr effect (MOKE) is obtained in these LaFeO$_3$-based FIM semiconductors. In addition, the FIM semiconductors with high $T_C$ are also obtained by spin-dependent doping in some other AFM materials with high $T_N$, including BiFeO$_3$, SrTcO$_3$, CaTcO$_3$, etc. Our theoretical results propose a way to obtain high $T_C$ FIM semiconductors by spin-dependent doping in high $T_N$ AFM insulators and semiconductors