Effects of freeze-thaw cycle and dry-wet alternation on slope stability

The typical loess on high slopes along the BaoLan High-speed Rail, China, was selected as the research object. The influence of the freeze-thaw cycle and dry-wet alternation on the shear-strength parameters of the unsaturated loess was investigated by laboratory experimental methods. Moreover, the temperature field, seepage field, and stability of slopes with different gradients were simulated under the effect of the freeze-thaw cycle and dry-wet alternation by using the geotechnical analysis software Geo-Studio. The research results showed(1) when the freeze-thaw cycle was repeated on the slope, with the frozen depth increasing, the melted depth did the same; besides, the closed loop of isotherms formed on the slope;(2) under the action of dry-wet circulation, the negative pore-water pressure and volumetric water content showed an upward tendency. However, owing to the different slope gradients, rainfall infiltration was not the same. As time went by, the differences of the negative pore-water pressure and volumetric water content between the slopes of different gradients continued to increase;(3) with the freeze-thaw cycle and dry-wet alternation increasing, the slope-safety factor decreased. Especially in the early period, the slope-safety factor changed remarkably. For slopes undergoing freeze-thaw action, the slope-safety factor was negatively correlated with the gradient. However, with regard to slopes undergoing dry-wet alternation, the result became more complex because the slope-safety factor was related to both seepage strength and slope grade. Accordingly, further research is needed to study the effect of seepage strength and slope grade on the stability of loess slopes.

Exact Solutions to the Boussinesq-Burgers Equations

A nonlinear transformation from the solution of a linear equation to the solution of the Boussinesq-Burgers equations is derived by using the simplified homogeneous balance method. Based on the nonlinear transformation and various given solutions of the linear equation, various exact solutions, including solitary wave solutions, rational solutions, the solutions containing hyperbolic functions and the solutions containing trigonometric functions, of the Boussinesq-Burgers equations are obtained.

STRUCTURAL AND ADSORPTION RELATIONSHIP OF MACROPOROUS R ESIN IN HEMOPERFUSION

In order to achieve high adsorption capacity of adsorbents in hemoperfusion,macroporous resins were tailor made with appropriate pore sizes and specific area. This allows the toxin molecules to diffuse freely within the channels ofthe porous resins and rinally reach the adsorption sites.Macroporous resin NK - 107 having small pore size and large Surface area(1086cm2) were synthesized which showed a high adsorption capacity of 82 - 94%for small molecules such as hypnotic and sedative drugs. For the adsorption of middle molecules i. e. Vit B12 or cytochrome C adsorbents having large pore sizes weretailor made. In the case of the adsorption of unconjugated bilirubin which is a verybig molecule, the pore size of the adsorbent should be at least>160A. NK - 110 istailor made with a very big pore size,which have a high adsorption capacity of 87%for bilirubin. DNA immobilized on carbonized resins,which have a porous structurewith a large surface area of 1000m2/g,can adsorb DNA antibody effectively. Resultsfrom animal and clinical trials indicated that the above tailor - made adsorbentshave a high efficacy in the removal of endogenous and exogenous toxins in hemoperfusion.