枣庄市农业机械化发展薄弱环节探究

“工欲善其事,必先利其器”。破解今后“谁来种地”“怎么种好地”这一难题,唯有大力发展农业机械化,通过发展现代农业装备,改善农业生产条件,解放农村劳动力,使现代职业农民生活更体面。当前枣庄市农机化发展存在诸多结构性矛盾,在全面梳理枣庄农机化发展现状的基础上,通过对枣庄市农业机械化发展薄弱环节进行深层次探究,找出症结、对症施策、助力发展。

Influence of Erosion Induced by NaCl on the Mechanical Performances of Alkali-Activated Mineral Admixtures

In this paper,the influence of NaCl freeze-thaw(F-T)cycles and dry-wet(D-W)alternations on theflexural,com-pressive and bonding strengths of alkali-activatedfly ash(FA)and a blast furnace slag powder(BFS)is investi-gated.The considered NaCl concentration is 3%.The effect of polypropylenefibers on the mechanical strengths is also examined.Scanning electron microscopy(SEM),thermogravimetry(TG)and X-ray diffraction(XRD)are selected to discern the mechanisms underpinning the NaCl-induced erosion.The obtained results indicate that the best results in terms of material resistance are obtained with admixtures containing 60%BFS and 40%FA in terms of mass ratio and 3%polypropylenefibers in terms of volume ratio.The maximum rates of decrease of theflexural,compressive and bonding strengths after 300 NaCl F-T cycles are 21.5%,20.3%and 22.6%,respec-tively.The corresponding rates of decrease due to NaCl D-W alternations are 28.1%,26.1%and 31.5%,respec-tively.The TG curves show that the alkali-activating activity of BFS is higher than that of FA.Moreover,in thefirst case,the microstructure of the hydration products is more compact.The results also show that NaCl F-T cycles lead to increasing cracks in the alkali-activated BFS.

Overexpression of the mTERT gene by adenoviral vectors promotes the proliferation of neuronal stem cells in vitro and stimulates neurogenesis in the hippocampus of mice

We sought to construct the adenoviral vector carrying the gene encoding mouse telomerase reverse transcriptase（mTERT）,as well as detect its expression and effect on the proliferation of neuronal stem cells.mTERT was am-plified by RT-PCR and then the eukaryotic expression vector of pDC-EGFP-TERT was constructed.After DNA sequence analysis,we detected that there were 293 cells transfected with pDC-EGFP-TERT and helper adenovirus plasmid pBHG lox ΔE1,and three Cre using Lipofectamine 2000 mediation,named Ad-mTERT-GFP,to pack-age adenoviral particles.The Ad-mTERT-GFP was used to infect neuronal stem cells and then the expression and activity of mTERT were detected.In addition,Bromodeoxyuridine labeling test identified the impact of mTERT overexpression on proliferation of neuronal stem cells.The recombinant adenoviral vector confirmed that mTERT was successfully constructed.Overexpression of mTERT stimulated the proliferation of neuronal stem cells both in vitro and in vivo.mTERT overexpression via adenoviral vector carrying mTERT cDNA upregulated the ability of proliferation in neuronal stem cells.

Hydrophobic organic coating based water–solid TENG for water-flow energy collection and self-powered cathodic protection

Water-solid triboelectric nanogenerators(TENGs),as new energy collection devices,have attracted increasing attention in ocean energy harvesting and selfpowered sensing.Polyacrylic acid(PAA)coating,usually used on the surface of marine equipment,has the property of anti-aging and anti-wear but limits triboelectrical output when used with TENGs.In this paper,polyacrylic acid coating was modified with fluorinated polyacrylate resin(F-PAA)to increase its triboelectrical output,by 6 times,and also to increase its anti-corrosion property.In addition,the corrosion resistance property can be further enhanced by cathodic protection using the electrical output generated by the water-flow triboelectrical energy transfer process.Given their easy fabrication,water-flow energy harvesting,and corrosion resistance,PAA/F-PAA coating-based TENGs have promising applications in river and ocean energy collection and corrosion protection.