Composites Based on GM(1,1)-Markov in the Salt Spray Corrosion Environment

This study was designed to solve the problem of magnesium hazards due to potash extraction in the salt lake region.Using basalt fiber(BF)as the reinforcement material and magnesium oxychloride cement(MOC)as the gelling material,a BF/MOC composite material was prepared.Firstly,the effect of BF addition content on the basic mechanical properties of the composites was investigated.Then,through the salt spray corrosion test,the durability damage deterioration evaluation analysis was carried out from both macroscopic and microscopic aspects using mass change,relative dynamic modulus of elasticity(RDME)change,SEM analysis and FT-IR analysis.Finally,a GM(1,1)-Markov model was established to predict the durability life of composite materials by using durability evaluation indicators.The results show that:when the BF content is 0.10%(by volumetric content),the composites have the best mechanical properties and resistance to salt spray corrosion.However,when the volume of BF content exceeds 0.10%,a large number of magnesium salt crystallization products are observed from the microscopic point of view,and the corrosion of the main strength phase of MOC is more serious.The prediction results of the GM(1,1)-Markov model are highly identical with the raw data.In addition,using the change of RDME as a predictor,RDME is more sensitive to environmental factor compared to the change of mass.Predictions using the change of RDME as a threshold indicate that MOC-BF0.10 has the longest durability life,which is 836 days.The model is important to promote the application of MOC composites in the salt lake region and to promote the healthy development of green building materials.

The Feasibility of Basalt Rock Powder and Superfine Sand as Partial Replacement Materials for Portland Cement and Artificial Sand in Cement Mortar

The research gap on the feasibility of basalt rock powder(BRP)and superfine sand(SS)in preparation of cement mortar is significant.This study examines probable changes occurred in the modified cement mortar due to incorporation of certain quantity of basalt rock powder and superfine sand in mixture proportion.The cement mortar included Portland cement,artificial sand and water as principal mixture constituents.Then,basalt rock powder and superfine sand were added as partial replacement materials for Portland cement and artificial sand respectively.Therefore,replacement percentages were 10%,15%,20%,25%and 30%when the basalt rock powder replaced Portland cement and in case the artificial sand was replaced by superfine sand,10%,20%,30%,40%and 50%.Then,the strength indexes such as flexural strength,compressive strength,ultrasonic pulse velocity and dynamic elastic modulus were investigated.The results show that the presence of basalt rock powder in mixture proportion increased the flexural and compressive strengths of cement mortar however the cement mortar that contained superfine sand illustrated inadequate mechanical performance as flexural and compressive strengths decreased remarkably.Moreover,when basalt rock powder and superfine sand were included together in mixture proportion,the cement mortar’s mechanical performance declined compared to that of the reference cement mortar.Despite the fact that basalt rock powder and superfine sand weakened the cement mortar’s mechanical properties,it was found that they can be added into the cement mortar as partial replacement of Portland cement and artificial sand in the following ratios:from 10%to 25%when basalt rock powder replaces Portland cement and from 10%to 20%when artificial sand is replaced by superfine sand.

合成致死在精准肿瘤学中的应用

合成致死是指两个非致死性基因同时失活从而导致细胞死亡的现象.近来,合成致死原理已经成功用于癌症精准治疗.癌症在其发生、发展和恶化过程中,积累了大量不能靶向的驱动突变,我们可以用药物精准抑制这些突变的合成致死搭档,从而特异性杀死癌细胞,不危害健康细胞.本文详细介绍了癌症的驱动突变,探讨了合成致死原理及其在癌症精准治疗中的应用;进一步探讨了基于DNA修复机制的BRCA1/2缺陷,激活RAS突变,MYC突变,肿瘤抑制基因TP53以及功能性缺失PTEN的合成致死性研究进展;最后展望了这种策略在无法靶向的驱动突变应用前景,为实现更有效、毒性更低的精准治疗提供方向,是抗癌药物研究的新热点.