Analyses of pion-nucleon elastic scattering amplitudes up to O(p4)O(p^4) in extended-on-mass-shell subtraction scheme

We extend the analysis of elastic pion-nucleon scattering up to $O(p^4)$ level using extended-on-mass-shell subtraction scheme within the framework of covariant baryon chiral perturbation theory. Numerical fits to partial wave phase shift data up to $\sqrt{s}=1.13$ GeV are performed to pin down the free low energy constants. A good description to the existing phase shift data is achieved. We find a good convergence for the chiral series at $O(p^4)$, considerably improved with respect to the $O(p^3)$-level analyses found in previous literature. Also, the leading order contribution from explicit $\Delta(1232)$ resonance and partially-included $\Delta(1232)$ loop contribution are included to describe phase shift data up to $\sqrt{s}=1.20$ GeV. As phenomenological applications, we investigate chiral correction to the Goldberger-Treiman relation %$\Delta_{GT}$ and find that it converges rapidly, and the $O(p^3)$ correction is found to be very small: $\simeq 0.2$. We also get a reasonable prediction of pion-nucleon sigma term $\sigma_{\pi N}$ up to $O(p^4)$ by performing fits including both the pion-nucleon partial wave phase shift data and the lattice QCD data. We report that $\sigma_{\pi N}=52\pm7$ MeV from the fit without $\Delta(1232)$, and $\sigma_{\pi N}=45\pm6$ MeV from the fit with explicit $\Delta(1232)$.Comment: The final version published in Phys.Rev. D 87, 054019 (2013

Development of Bionic Air Cooler Used in High Temperature Coal Mine

In high temperature coal mine, the surface air cooler heat exchange efficiency decreases greatly because of high humidity and dust. In order to improve the heat exchange efficiency, the surface of the air cooler needs to be designed to reduce the dust adhesion, and improve the heat exchange efficiency. Based on the self-cleaning effect of lotus leaf, the surface of air cooler is designed and fin and tube are processed into the constructure of lotus leaf surface. With Ansys, the cooling effect of air cooler is simulated, and the experiment is done to test the heat exchange effect of the common air cooler and bionic air cooler in lab. By analysis, it can be concluded that the surface of bionic air cooler has the function of self-cleaning, and the structure can increase the heat exchange efficiency, which is higher above 30% than that of common air cooler. Key words: High temperature coal mine; Air cooler; Self-cleaning; Heat exchange efficienc

A Study on SSVEP-Based BCI

Abstract⎯Brain-computer interface (BCI) can help the deformity person finish some basic activities. In this paper, we concern some critical aspects of SSVEP based BCI, including stimulator selection, method of SSVEP extracting in a short time, stimulating frequency selection, and signal electrode selection. The conclusion is that the stimulator type should be based on the complexity of the BCI system, the method based on wavelet analysis is more valid than the power spectrum method in extracting the SSVEP in a short period, and the selections of stimulating frequency and electrode are important in designing a BCI system. These contents are meaningful for implementing a real SSVEP-based BCI. Index Terms⎯Brain-computer interface, electroencephalogram, steady-state visual evoked potential

(4S,5S)-2-(2-Thien­yl)-1,3-dioxolane-4,5-dicarboxamide

In the title compound, C9H10N2O4S, which is an important inter­mediate for the preparation of anti­tumor platinum drugs, the dioxolane ring adopts an envelope conformation with the C atom bonded to the thienyl ring at the flap position. Intra­molecular N—H⋯O and C—H⋯O hydrogen bonds result in the formation of two five-membered rings having envelope conformations. In the crystal structure, inter­molecular N—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network

Radio Sensing with Large Intelligent Surface for 6G

This paper leverages the potential of Large Intelligent Surface (LIS) for radio sensing in 6G wireless networks. Major research has been undergone about its communication capabilities but it can be exploited as a formidable tool for radio sensing. By taking advantage of arbitrary communication signals occurring in the scenario, we apply direct processing to the output signal from the LIS to obtain a radio map that describes the physical presence of passive devices (scatterers, humans) which act as virtual sources due to the communication signal reflections. We then assess the usage of machine learning (k-means clustering), image processing and computer vision (template matching and component labeling) to extract meaningful information from these radio maps. As an exemplary use case, we evaluate this method for both active and passive user detection in an indoor setting. The results show that the presented method has high application potential as we are able to detect around 98% of humans passively and 100% active users by just using communication signals of commodity devices even in quite unfavorable Signal-to-Noise Ratio (SNR) conditions