Influence of High-Robustness Polycarboxylate Superplasticizer on the Performances of Concrete Incorporating Fly Ash and Manufactured Sand

Using ethylene glycol monovinyl polyoxyethylene ether,2-acrylamido-2-methylpropane sulfonic acid(AMPS)and acrylic acid as the main synthetic monomers,a high robustness polycarboxylate superplasticizer was prepared.The effects of initial temperature,ratio of acid to ether,amount of chain transfer agent,and synthesis process on the properties of the superplasticizer were studied.The molecular structure was characterized by GPC(Gel Permeation Chromatography)and IR(Infrared Spectrometer).As shown by the results,when the initial reaction temperature is 15℃,the ratio of acid to ether is 3.4:1 and the acrylic acid pre-neutralization is 15%,The AMPS substitution is 10%,the amount of chain transfer agent is 8%,and the performance of the synthesized superplasticizer is the best.Compared with commercially available ordinary polycarboxylate superplasticizer in C30 concrete prepared with manufactured sand and fly ash,the bleeding rate decreases by 52%,T50 decreases by 1.2 s,and the slump time decreases by 1.1 s.In C60 concrete prepared with fly ash and river sand,the bleeding rate decreases by 46%,T50 decreases by 0.8 s,and the slump time decreases by 3.2 s.

An Analysis of the Literature’s Truth, Goodness and Beauty

Literary works are an important medium for the exploration of truth,goodness and beauty,of which human beings have never stopped the discussion and pursuit.First of all,this paper gives an overview of what are truth,goodness and beauty.Then it summarizes what has been the focus of the unity of truth,goodness and beauty between China and the West.Finally,this paper values the analysis of the truth,goodness and beauty of literary works:the facts of literature should be true,the purpose should be good,and the form should be beautiful.Based on this,the author puts forward the relationship between the three harmonies with the unity of truth,goodness and beauty in literary works,which the author believes is the ultimate pursuit of literature.

On Linguistics Course Construction to Foster English Application-oriented Talents in Tibetan Ethnic Colleges: A Case Study of Sichuan Minzu College

Under the social background of application-oriented transformation of local colleges and universities,the construction of linguistics course for English majors in Tibetan ethnic colleges should actively adapt to the requirements of the times,update the teaching concept,take application as orientation,take combination of language theory and language practice as the principle,take interlinguistic study as the basic content and focus on language acquisition and second language teaching of extralinguistic study.In view of the existing problems in this course,the reform should take the following aspects into consideration:redefining the training objectives,finding out the course orientation,revising the teaching contents,improving the teaching methods,enriching the teaching means,reforming the evaluation methods,enhancing the teaching practice,strengthening the construction of the teaching staff and the construction of the course resources,to make the linguistic theoretical courses related to and guide students’language learning practice,to make it close to and be applied in students’daily life,to prepare students to be future teachers or researchers and most importantly to train qualified application-oriented English teachers for ethnic areas in Tibet.

Effect of the addition of TEOS on the SiC fibers fabricated by electrospinning

Polycarbosilane(PCS)has been widely used to fabricate silicon carbide(SiC)fibers via pyrolysis.In this paper,for improving the morphology of SiC fibers,tetraethyl orthosilicate(TEOS,m=1 g,3 g and 5 g,respectively)was added into the PCS precursor solution(containing 1.5 g PCS).The continuous fibers have been prepared by electrospinning,and then the SiC fibers were synthesized by calcination at 1300℃,1400℃and 1600℃for 4 h respectively with a heating rate of 10℃/min in flowing nitrogen(N_(2)).The morphologies of the fibers were investigated by the scanning electron microscope(SEM)and it could be seen that the crystallinity of the SiC fibers was lower,the length of the SiC fibers was increased,and the diameter was uniform with the increase of the addition amount of TEOS.