In order to explore the dynamic response of square set square steel tube-reinforced con-crete(ST-RC)columns under the lateral impact loading,an impact model of square set square ST-RC columns is established based on the finite element software ABAQUS.The reliability of the model is verified by the existing test data.The model is used to analyze the impact force response and dynamic deformation of square set square ST-RC columns under the lateral impact loading.The results indicate that:(1)The failure modes of the columns under the impact loading mainly include impact point damage,columns damage and impact point failure;(2)The mid-span displacement increases with the increase of impact velocity and mass,while decreases with the increase of stiffness of the columns.The peak and platform values of impact force have different rules due to the influence of various parameters;(3)The mid-span displacement and residual displacement are more obviously affected by the impact body than by its own material and stiffness.The research results can provide reference for the study of anti-collision performance of this kind of structure.
The weed inhibitory effects of culturable dominant microbial strains in the rhizosphere of various wheat varieties are evaluated to explore the allelopathic effect mechanism of the rhizosphere of spring wheat planted in Qinghai.The dominant strains in the rhizosphere soil of 20 kinds of wheat(lines)are isolated and purified.The biological activity of the strains'fermentation broth is evalua-ted by measuring the seed germination and seedling growth of Avena fatua L..The results show that the fermentation broths of bacterial and fungal strains have varying degrees of inhibitory effects on the growth of Avena fatua L.seedlings and plants.Bacterial strains X3,X4,X8,X12,X16 and X20 all have certain inhibitory activity on Avena fatua L.,with X20 having the best control effect.Fungal strains Z1,Z2,Z3,Z16 and Z17 all have certain inhibitory activity on Avena fatua L.,with Z2 having the best herbicidal activity.According to molecular biology identification,strain X20 belongs to the genus Bacillus and strain Z2 belongs to the genus Penicillium.This study provides a theoretical basis for the allelopathic effect mechanism of dominant microbial strains in the rhizosphere of spring wheat varieties(lines)on weeds,and also provides new strain resources for the development of biological herbicides for weed control of Avena fatua L.in the wheat fields.
In order to systematically analyze the reinforcement effects of advanced small pipe grouting pre-reinforcement technology in the tunnel fault fracture zone,based on a tunnel fault fracture zone reinforcement project by using the technology,the advanced geological prediction radar image is used to analyze the fragmentation degree of rock mass after the reinforcement.The BQ value of the rein-forced rock mass is obtained through the field coring and test,which is compared with the value in the survey stage to characterize the effects of the technology on the grade of surrounding rock.The time-volume method is used to calculate the seepage volume after the reinforcement.Leica TS09plus-2R500 station is used to observe the displacement inside and outside the tunnel after the reinforcement.The advanced geological prediction,lithology analysis,seepage statistics and settle-ment monitoring data inside and outside the tunnel in the fault fracture zone are analyzed on the strength of above methods and technology.The results show that the advanced small pipe grouting re-inforcement technology can cross the fault fracture zone within a controllable range,but it cannot im-prove the degree of fragmentation of surrounding rock mass within the depth range of the tunnel with poor water sealing effect.The deformation caused by the initial excavation is the main deformation that crosses tunnel fault fracture zone,and the initial support should be completed in advance.
Improving water efficiency is one of the important ways to solve the shortage of water re-sources.The variations in farmland irrigation water efficiency,industrial water efficiency and domes-tic water efficiency in Xining from 2000 to 2019 are analyzed by using Data envelopment analysis(DEA)to improve the water efficiency.The results show that:(1)The irrigation water efficiency of farmland in Xining was relatively low from 2005 to 2010,which has been increasing year by year since 2010;the values of comprehensive technical efficiency,pure technical efficiency and scale efficiency were all 1 in 2017,indicating that the irrigation water for farmland was in the optimal state.(2)The industrial water efficiency in Xining is showing an increasing trend year by year.The industrial water efficiency was the highest in 2017,with effective comprehensive technical efficiency,pure technical efficiency and scale technical efficiency;there was a slight decrease in scale and technical efficiency in 2018 and 2019,while pure technical efficiency was effective.In addition,there was still room for industrial water.(3)The water efficiency of hotels,hospitals,and residential areas in Xining is relatively good,while that of education and government agencies is low.Domestic water consumption includes urban public water and residential domestic water.Both urban public water and residential domestic water increased first and then decreased from 2000 to 2019.In recent years,they have tended to stabilize and conform to the laws of urban development.In summary,it is necessary to allocate water resources reasonably and improve residents'water-saving awareness to improve water efficiency.
In order to recycle the active ingredients in the cleaning solution of Chenopodium quinoa Willd.and improve its stability,zein and sodium alginate are taken as wall materials to prepare mi-crocapsules of active ingredients in the solution by using drip method.The preparation process is op-timized by orthogonal tests.The stability and in vitro release performance of microcapsules are ana-lyzed as well.The results show that the optimal conditions for preparing microcapsules are 1.0%mass fraction of zein,1.5%of sodium alginate,3.0%of calcium chloride and 3 mL concentration of the solution.The microcapsules are approximately spherical in shape,with a particle size of approxi-mately 2.5 mm and an embedding rate of 86.74%.Compared with the freeze-dried product of the unencapsulated Chenopodium quinoa Willd.cleaning solution,the retention rate of active ingredients in the microcapsules increase by 2.70%to 5.94%at different temperatures,while the release rates reach 11.35%and 19.42%respectively after 3 hours of digestion in the simulated gastric and intes-tinal fluids.In conclusion,microcapsulation can achieve the loading and recovery of the active ingre-dients in the cleaning solution of Chenopodium quinoa Willd.and effectively improve the stability of active ingredients.
