Abstract: The present disclosure provides a method and system for mining rare earth ore using a direct current. The system includes: liquid injection holes arranged in a mining area; electrodes arranged in the liquid injection holes; a leaching agent added into the liquid injection holes; and an electrification control system dividing the mining area into M equal parts and electrifying the electrodes using a cyclical alternate electrification method from 1 to M. In an Nu electrification cycle, all electrodes of an (M×n+N)th row are connected to a positive electrode of a power supply, and all electrodes of an (M×n+N+1)th row are connected to a negative electrode of the power supply. The cyclical alternate electrification method reduces at least (M?1)/M of power consumption, and the rare earth mining efficiency is improved.

Abstract: A power transmission and transformation project acceptance method based on building information modeling (BIM) and point cloud measurement includes: S1: constructing a BIM model based on a design drawing, where the BIM model includes standard parameters of key components of a power transmission and transformation project; S2: obtaining point cloud data, and constructing a point cloud data model based on the point cloud data, where the point cloud data model includes actual parameters of the key components of the power transmission and transformation project; S3: comparing the BIM model with the point cloud data model to obtain construction acceptance data; and S4: visualizing the construction acceptance data and outputting an acceptance report to complete acceptance of the power transmission and transformation project. The BIM model and the point cloud data model are compared to implement rapid and efficient acceptance of the power transmission and transformation project.

Abstract: A metallocene compound having a structure shown by formula (I). A functional group connected to a bridging atom of the metallocene compound is an amine-substituted group and/or a metallocene-substituted group and/or a substituted metallocene group. A metallocene catalyst containing the metallocene compound has high catalytic activity, and can synthesize metallocene polypropylene having high isotacticity.

Abstract: A catalytic reaction of ethylene oxide (EO) coupling with syngas to produce 1,3-propanediol (1,3-PDO) is disclosed. The catalytic reaction of EO, carbon monoxide and the alcohol uses a N,O-ligand coordinated metal complex catalyst. The reaction is carried out in an organic solvent in the presence of an additive at the temperature of 30-190° C. and the CO pressure of 1-150 atm for 0.1-200 h to prepare 3-hydroxypropinate (3HP). The catalytic reaction of 3HP with dihydrogen uses a copper-containing mixed metal silicon oxide catalyst with a molecular formula of M?uCuvSiyOz. The reaction is carried out at 80-400° C. and 20-150 atm for 0.1-200 h to prepare the 1,3-PDO. The yield of the 1,3-PDO can reach to 73%. The alcohol byproduct generated in the second step catalytic hydrogenation reaction can be recycled to use for the first step catalytic reaction by the ring opening-carbonylation-esterification.

Abstract: The present invention discloses an ultra-low frequency (ULF) tuned liquid mass damper, and relates to the technical field of bridge vibration control. The tuned damper includes a damping box which is provided with a spring set secured at one end to the damping box, the other end connected with a mass block. The damping box is filled with damping liquid, and the mass block is completely immersed or partially immersed in the damping liquid. The damping ratio of the ULF tuned liquid mass damper ranges from 3% to 35%, and the inherent frequency 0.05 to 0.5 Hz. The ULF tuned liquid mass damper, according to the present invention, can fully utilize the additional mass of the damping liquid, and with the buoyancy effect of the liquid, maintain the frequency of structural vibration below 0.

Abstract: The present invention discloses an ultra-low frequency (ULF) tuned liquid mass damper, and relates to the technical field of bridge vibration control. The tuned damper includes a damping box which is provided with a spring set secured at one end to the damping box, the other end connected with a mass block. The damping box is filled with damping liquid, and the mass block is completely immersed or partially immersed in the damping liquid. The damping ratio of the ULF tuned liquid mass damper ranges from 3% to 35%, and the inherent frequency 0.05 to 0.5 Hz. The ULF tuned liquid mass damper, according to the present invention, can fully utilize the additional mass of the damping liquid, and with the buoyancy effect of the liquid, maintain the frequency of structural vibration below 0.

Abstract: A ligand based chromium catalyst and application in catalyzing ethylene oligomerization are disclosed. The chromium catalyst is formed by a chromium compound and an organic ligand containing P and/or N. The substituents on N and P of the ligand can be replaced, whereby selective ethylene trimerization and tetramerization can be realized so as to produce 1-hexene and 1-octene at the same time.

Abstract: A ligand based chromium catalyst and application in catalyzing ethylene oligomerization are disclosed. The chromium catalyst is formed by a chromium compound and an organic ligand containing P and/or N. The substituents on N and P of the ligand can be replaced, whereby selective ethylene trimerization and tetramerization can be realized so as to produce 1-hexene and 1-octene at the same time.