Flavonoids produced by legume roots are signal molecules acting as nod gene inducers for the symbiotic rhizobium partner. Nevertheless, the changes of flavonoids in root exudates in intercropping system are still unknown. Based on pot experiment of faba bean and wheat intercropping, here we showed that faba bean and wheat intercropping increased the nodules number and dry weight, dry weight per nodule of faba bean compared with those found in monocropping, and the increase of faba bean nodulation was likely caused by the enhancement with flavonol, isoflavone, chalcone and hesperetin in its root exudates. It also promoted exudation of five types of flavonoids by wheat compared with monocropping. Our findings suggest that the flavonoids in root exudates have a positive effect on the nodulation and nitrogen fixation of faba bean in faba bean and wheat intercropping. ARTICLE HISTORY

In order to solve the problems that the current components using for recycling the film in the Plastic film recycling machine are not suitable for a large quantity of coating stubble corn plastic film recycling. Based on the work principle of “shovel-excavation screening”, developing the whole design:shovel film stubble→topsoil delivery→soil sieve→set the heap surface.By optimizing the design and combination of various components to achieve plastic film recycling of corn stubble. This machine can meet the requirements of recycling the film, raising the stubble and grounds care in the alpine arid regions. It can solve the difficult problems about the uneasy recovery of the serious damage film and the film recycling of the stubble crops like corn.The experiment showed:①The plastic film recycling on topsoil can use the way of shoveling, in the first step all the film was picked up from the topsoil.②At the same time it can be able to recycle the film containing 22.5% corn stubble.③ The plastic film recovery on the topsoil can reach or over 90%.

Spherical and octahedral Cu2O nanocrystals were prepared by reducing copper acetate monohydrate (Cu (CH3COO)2·H2O) with hydrazine hydrate (N2H4·H2O) at ambient temperature and pressure. The influence of solution composition on the morphology and microstructure of Cu2O nanocrystals were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Ultraviolet and visible light spectrometer (UVvis) was employed to investigate the photocatalysis behavior of the Cu2O samples. The results show that Cu (OH)2 was initially formed with the addition of NaOH and then reduced into Cu2O by N2H4·H2O. At the same time, a portion of Cu2O particles were further reduced to Cu, but the increasing of O2 contents in the solution under vigorous stirring reconvert Cu into Cu2O whichlead to the formation of pure Cu2O nanocrystals. The alkaline condition which provided by NaOH was the prerequisite for obtaining spherical and octahedral Cu2O crystals. The facile method was provided to fabricate Cu2O nanocrystals with outstanding photocatalysis performance at low temperature, which may play an important role in sewage treatment and organic pollutants decomposition.

To ensure the influence degree on the environment during constructing metro-station based on shield tunneling is very important in the subway construction. After the shield machine passed the metro-station, the field monitoring of these segments is carried on during getting rid of the segments. The connecting seam opening length of segments, the tunnel convergence and the internal force of the segments’ bolt are estimated. The results show that the opening length of segments of circular connecting seam is larger than that of longitudinal connecting seam, and all the changes of the opening length value is within 1.5 mm. Tunnel convergence change generally contains a gradually becoming smaller and a gradual recovery process, and the tunnel convergence is primarily vertical. Bolt internal force change generally involves stress increasing rapidly, and then decreasing slowly. The field monitoring study will potentially provide the knowledge and reference for similar projects

The stability control of surrounding rock is a relatively important problem in tunnel boring machine (TBM) construction. The tunnel convergence deformation value was monitored in field while TBM passing weak and broken section of hydraulic tunnel. The correlation between tunnel convergence and surrounding rock stability is analyzed. The monitoring results show that: the characteristic of weak and broken Strata is closely correlated with some geological conditions, such as fault development, intrusive contact of orthophyre and lamprophyre veins. These supporting measures can well ensure the stability of surrounding rock in weak and broken section, such as sealing the inverted arch by using concrete of C25,reinforcing the inverted arch by steel arch of I10 and anchor construction in the roof. There is great difference between the properties of the weak and broken rocks on both sides, which is the main reason of the large tunnel convergence deformation. The monitoring results can provide reference for similar engineering in the future.