RESEARCH ON THE WATER-RESISTANCE OF MAGNESIUM OXYCHLORIDE CEMENT——I:THE STABILITY OF THE REACTION PRODUCTS OF MAGNESIUM OXYCHLORIDE CEMENT IN WATER

In this paper .the change of the crystalline phases in hardened magnesium oxychloride cement (MOC) paste in mater was analyzed by XRD. It was developed that the reaction products 5 phase or 3 phase of MOC are instable in water and can be changed into Mg(OH)2 by the action of water, which causes the content of 5 phase or 3 phase to be less and less,the content of Mg(OH)2 to be more and more and the strength to be the lower the lower,after hardended MOC paste was immersed in water. The change of 5 pliase and 3 phase into Mg(OH)2 is not a dissolve process, but a hydrolysis process. The hydrolysis products of 5 phase and 3 phase are Mg(OH)2 precipitation and soluble Cl-,AIg+ ions and H2O. The hydrolysis is sponta-neous thermodynamically and its chemical kinatic equation is C = C,,e-k Thus .it is suggested that only by enhancing the stability of 5 phase or 3 phase in water and preventing 5 phase or 3 phase from the hydrolyzing can the water resistance of MOC be improved well.

Preface Dr. QI Huibin

Corrosion is a damage or a change of state of materials caused by interactions between materials and environmental factors, which, together with fracture and wear, have become the three major reasons for the failure of structural materials. Normally, corrosion takes place or originates on or from the surface of materials. Therefore, surface technology （such as coating） is one of the important measures to mitigate and control the process of corrosion.

项目区尺度下新增耕地可持续利用综合评价——基于中国广东的案例分析

Cultivated land plays a pivotal role in ensuring national food security,particularly in populous nations like China,where substantial investments are made to develop cultivated land as a counterbalance to construction-occupied areas.Consequently,long-term,effective monitoring of the utilization of newly cultivated land becomes imperative.This study introduces a comprehensive monitoring framework,designed for refined scales,that leverages remote sensing data.The framework focuses on the sustainable utilization of newly cultivated land,emphasizing utilization sustainability,productivity stability,and landscape integration.Its effectiveness was validated through a case study in Guangdong province,China.The results revealed satisfactory utilization sustainability and improved productivity stability of newly cultivated land in Guangdong,though landscape integration showed sub-optimal results.Furthermore,the comprehensive evaluation categorized the newly cultivated land into three levels and eight types.The study recommends enhancing the site selection process for newly cultivated land and improving the long-term monitoring,as well as incentive and constraint mechanisms,for their utilization.This study can provide a scientific reference to bolster the implementation of cultivated land protection policies,thereby contributing significantly to high-quality economic and social development.

Stabilized oil production conditions in the development equilibrium of a water-flooding reservoir

Water injection can compensate for pressure depletion of production.This paper firstly investigated into the equilibrium issue among water influx,water injection and production.Equilibrium principle was elaborated through deduction of equilibrium equation and presentation of equilibrium curves with an“equilibrium point”.Influences of artificial controllable factors(e.g.well ratio of injection to production and total well number)on equilibrium were particularly analyzed using field data.It was found that the influences were mainly reflected as the location move of equilibrium point with factor change.Then reservoir pressure maintenance level was especially introduced to reveal the variation law of liquid rate and oil rate with the rising of water cut.It was also found that,even if reservoir pressure kept constant,oil rate still inevitably declined.However,in the field,a stabilized oil rate was always pursued for development efficiency.Therefore,the equilibrium issue of stabilized oil production was studied deeply through probing into some effective measures to realize oil rate stability after the increase of water cut for the example reservoir.Successful example application indicated that the integrated approach was very practical and feasible,and hence could be used to the other similar reservoir.

A dynamic two-zone model of continuous fluidized bed layering granulation with internal product classification

A dynamic two-zone model is proposed to address the formation of granulation and drying zones in fluidized bed layering granulation processes with internal product classification. The model assumes a constant volume for the granulation zone, but a variable overall volume for the fluidized bed to account for classified product removal. The model is used to study the effect of various process parameters on dynamics and process stability. Stability is shown to depend on the separation diameter of product removal and the flow rate of the injected liquid. A lower and upper range of separation diameters with stable process behavior are found. In an intermediate range instability in the form of self-sustained oscillations is observed. The lower stability boundary is in qualitative agreement with recent experimental observations （Schmidt, Bück, ＆ Tsotsas, 2015）; the upper boundary was reported in a theoretical paper by Vreman, Van Lare, and Hounslow （2009） based on a single zone model.