大学生思想政治教育“厚理论”与“轻传播”结合路径探析——基于新媒体时代特征研究

在新媒体时代,大学生思想政治教育需要提高理论教育的影响力和有效性,“厚理论”与“轻传播”缺一不可。增强理论的广度和深度,并以简洁轻快的传播方式推动马克思主义大众化传播,才能吸引广大青年学生,提升大学生思想政治教育实效性。因此,在对理论进行提炼整合,确保理论质量和厚度的同时,要加强大学生思想政治教育人才队伍建设,创新传播途径,优化思想政治工作总体环境,实现“厚理论”与“轻传播”有机结合,推动大学生思想政治教育长效化发展。

Safety thickness analysis of tunnel floor in karst region based on catastrophe theory

Based on the tunnel shape, span and depth, the previous elliptical plate model and clamped beam model were modified.The modified model was applied to different situations. For the elliptical plate model, the water effects were considered. For the clamped beam model, water and horizontal stress were considered. Corresponding potential functions and cusp catastrophe models of rock system were established based on the catastrophe theory. The expressions of critical safety thickness were derived with necessary and sufficient conditions. The method was applied to the practical engineering. Some parameters related to the stability were discussed. The results show that elastic modulus and thickness are advantageous to the floor stability, and that the load, span,horizontal stress and water are disadvantageous to the floor stability.

Theoretical analysis on water-inrush mechanism of concealed collapse pillars in floor

In order to study the water-inrush mechanism of concealed collapse pillars from the mechanical view, a mechanical model for water-inrush of collapse pillars has been established based on thick plate theory of elastic mechanics in this paper.By solving this model the deformation of water-resistant rock strata under the action of water pressure and the expression of critical water pressure for collapse pillar waterinrush have been obtained The research results indicate that：the boundary conditions and strength of water-resistant strata play important roles in influencing water-inrush of collapse pillars.The critical water-inrush pressure is determined by both relative thickness and absolute thickness of water-resistant strata.

A fuzzy logic model to predict the out-of-seam dilution in longwall mining

The longwall mining method is often affected by the out-of-seam dilution （OSD）. Therefore, predicting and controlling of dilution are important factors for reducing mining costs. In this study, the fuzzy set theory and multiple regression models with parameters, including variation in seam thickness, dip of seam, seam thickness, depth of seam, and hydraulic radius as inputs to the models were applied to pre- dict the OSD in the longwall coal panels. Field data obtained from Kerman and Tabas coal mines, lran were used to develop and validate the models. Three indices including coefficient of determination （R2）, root mean square error （RMSE） and variance account for （VAF） were used to evaluate the perfor- mance of the models. With 10 randomly selected datasets, for the linear, polynomial, power, exponential, and fuzzy logic models, R2, RSME and VAF are equal to （0.85, 4.4, 84.4）, （0.61, 7.5, 59.6）, （0.84, 4.5, 72.7）, （0.80, 4.1, 79.6）, and （0.97, 2.1, 95.7）, respectively. The obtained results indicate that the fuzzy logic model predictor with R2 = 0.97, RMSE = 2.1, and VAF = 95.7 performs better than the other models.

A new method determining safe thickness of karst cave roof under pile tip

Cave roofs are used to support pile foundation in many engineering projects. Accurate stability analysis method of cave roof under pile tip is important in order to ensure the safety of the pile foundation structure. Firstly the mechanical model to analysis the stability of cave roof under pile tip is founded aiming to solve the problems that the simplified mechanical model has. Secondly, the boundary of cave roof is simply supposed to be supported according to the integrity of the rock mass in the boundary of cave roof. Thirdly, based on the theory of plates and shells, the simplified model is calculated and the theoretical calculation formula to determine the safe thickness of cave roof under pile tip can be obtained when the edges of the cave roof are simply supported. In the end, the analysis of the practical engineering project proves the feasibility and the rationality of the method which can be a new method to calculate the safe thickness of cave roof under pile tip.

Suitable layout of gate roads related to slice mining in an ultra-thick unstable coal seam

We determi：ned a suitable gate road layout in slice mining in an ultra-thick unstable coal seam, using theoretical anallysis and numerical calculations. Based on plasticity theory in terms of limiting equilibrium, the width of chain pillar in the upper slice was calculated to be 18 m. The stress distribution in the chain pillar after the upper slice was mined out was described with numerical simulation. The extent of the effect of stress on the upper chain pillar on the lower solid coal was obtained on the basis of an elastic solution of a distributed force loaded on a half-plane. Three layout designs for lower gate roads were pro- posed and a stability factor was introduced to analyze the stability of the lower pillar with numerical calculation. Gate road translation was determined as the most suitable layout method, which maximizes the extraction rate on the basis of the pillar stability.

Analysis of Heat Transfer Phenomenon in Magnetohydrodynamic Casson Fluid Flow Through Cattaneo–Christov Heat Diffusion Theory

Heat transport phenomenon of two-dimensional magnetohydrodynamie Casson fluid flow by employing Cattaneo-Christov heat diffusion theory is described in this work. The term of heat absorption/generation is incorporated in the mathematical modeling of present flow problem. The governing mathematical expressions are solved for velocity and temperature profiles using RKF 45 method along with shooting technique. The importance of arising nonlinear quantities namely velocity, temperature, skin-friction and temperature gradient are elaborated via plots. It is explored that the Casson parameter retarded the liquid velocity while it enhances the fluid temperature. Fhrther, we noted that temperature and thickness of temperature boundary layer are weaker in case of Cattaneo-Christov heat diffusion model when matched with the profiles obtained for Fourier＇s theory of heat flux.

Thermodynamic analysis of liquid bridge for fixed volume in atomic force microscope

In ambient condition,capillary forces are the major contributors to the adhesive forces between the tip of an atomic force microscope(AFM) and the sample.In general,capillary forces are thought to be related to water film thickness,contact time and relative humidity and so on.In this paper,an original analysis regarding the liquid bridge,based on the surface and interface thermodynamic theory,is proposed.The cases covered in the study include the capillary forces and temperature of liquid bridge for quickly drawn liquid bridge,and for nonvolatile liquid bridge.The study results show that variation in temperature may occur in the liquid bridge when it is stretched.

Electrocaloric Effect of P(VDF-TrFE)/SrTiO_3 Bilayer Thin Films

A phenomenological thermodynamic theory is applied to investigate the effect of misfit strgin and electric field on the electrocaloric effect of P（VDF-TrFN）/SrTiO3 bilayer thin films. Theoretical results indicate that the low electric field results in the decrease of the average polarization with the increase of the relative thickness of SrTi03 layer, and the high electric field has an opposite effect on it. Moreover, the electroealoric effect strongly depends on the electric field. The low electric field and the small field change can lead to a maximum of the electrocaloric effect, meanwhile the high electric field or the large field change results in the opposite trend.