A Study on Ecological College English Teaching

Classroom ecology refers to the classroom activities which are guided by educational philosophy of ecology. It promotes eco-classroom teaching and the full development of nature so as to make the classroom become truly holistic and sustainable and healthy ecosystems. This article aims to analyze the present status of college English teaching and research, providing suggestions for improving the quality of college English teaching

Punicalagin attenuated allergic airway inflammation via regulating IL4/IL-4Rα/STAT6 and Notch- GATA3 pathways

Allergic asthma is an inflammatory disease of the airways which has a complex etiology. Punicalagin, a major polyphenol present in pomegranates, is reported to possess various biological properties including antioxidant and antiproliferative effects. The current research aimed to evaluate the antiasthmatic effects of punicalagin in an Ovalbumin (OVA)-induced experimental model of asthma in female BALB/c mice. Treatment group animals received punicalagin (12.5, 25 or 50 mg kg–1 body mass) per day for 21 days from day 1 of OVA injection. Dexamethasone (DEX) was administered to a separate group of mice, as the standard drug control. Inflammatory cell infiltration into the bronchoalveolar lavage fluid (BALF) was substantially decreased in punicalagin-treated mice. Punicalagin reduced Th2-derived cytokines and OVA-specific IgE levels. The IL-4/STAT6 and Notch/GATA3 signalling pathways were regulated on punicalagin administration. The data obtained illustrate the potency of punicalagin as an anti-asthmatic drug. Conclusively, the study\u27s observations suggest the potential therapeutic efficiency of punicalagin in allergic astha

One dimensional model for doubly degenerate electrons

A Hubbard-like model with SU(4) symmetry for electrons with two-fold orbital degeneracy is studied extensively. Exact solution in one dimension is derived by means of Bethe ansatz, where the sites are supposed to be occupied by at most two electrons. The features of ground state and excited states for repulsive coupling are shown. For finite N number of electrons, the configurations of quantum numbers are given explicitly and the spectra of excitations are obtained by solving the Bethe-ansatz equation numerically. For infinite N, the ground state and various kinds of low-lying excitations are obtained on the basis of thermodynamics limit.Comment: Revtex, 21 pages including 9 figures, PRB versio

Breakdown Characteristics of Varistor Ceramics

Breakdown characteristics are of great importance for varistor ceramics, which largely depend on Schottky barriers at grain boundaries. In order to enhance breakdown performance for meeting the requirement of device miniaturization, different doping methods are introduced to not only restrict grain size from additional phase but also manipulate defect structure of Schottky barrier at grain boundaries from substitution. Distribution of barriers is another key point affecting breakdown characteristics in varistor ceramics. Dimensional effect, which is detected in not only ZnO ceramics but also CaCu3Ti4O12 ceramics, is practically and theoretically found to be closely correlated with uniformity of grains. As a result, breakdown characteristics of varistors are dominated by combination effect of single barrier performance and spatial barrier distribution. In this chapter, enhanced breakdown field in CaxSr1−xCu3Ti4O12 ceramics, in situ synthesized CaCu3Ti4O12-CuAl2O4 ceramics, and CaCu3Ti4O12-Y2/3Cu3Ti4O12 composite ceramics are investigated from the aspect of Schottky barriers at grain boundaries. In addition, dimensional effect is found in both ZnO and CaCu3Ti4O12 ceramics, which are investigated from grain size distribution through theoretical and experimental analysis

Anti-rollover control of a heavy-duty vehicle based on lateral load transfer rate

With the rapid development of the highway network construction and heavy-duty vehicle market, the rollover accidents of heavy-duty vehicle continue to increase. In order to improve rollover stability of vehicle, a four degree of freedom (DOF) heavy-duty vehicle model is established. An anti-rollover control strategy is designed by using differential braking system to control the lateral load transfer rate (LTR). The dynamic simulation of vehicle with and without control is fulfilled in Matlab/Simulink. Then, the vehicle responses under typical angle step input are compared and analyzed with different road surface adhesion coefficient, vehicle speed, steering wheel angle and vehicle load. The results show that the proposed control strategy is able to improve vehicle rollover stability greatly and is also beneficial to vehicle yaw stability. The increase of road surface adhesion coefficient, vehicle speed, steering wheel angle or vehicle load has positive correlation with the rollover control effect