Abstract: The present disclosure provides an ecological governance method based on erosion prevention and control for a gentle slope farmland and relates to the technical field of ecological governance of farmlands. The ecological governance method based on erosion prevention and control for a gentle slope farmland includes the following steps: sampling a gentle slope farmland to investigate erosion thereof; and determining erosion of a gentle slope cultivated land and selecting a corresponding recovery strategy based on a detection result of a sample, a soil quality index (SQI), and a comprehensive vegetation quality index (VQI), where the recovery strategy includes a natural recovery method and a biological-farming comprehensive recovery method; enclosing the gentle slope cultivated land, fallowing the gentle slope cultivated land and reducing tillage; exterminating insect pests and poisonous weeds in the enclosed area; and turning over straws under soil by a cultivator. The growth of poisonous weeds is inhibited.

Abstract: Provided are a water-soluble Pd(II) complex, a synthesis method thereof and use thereof as a catalytic precursor. The complex has a chemical name, ammonium dinitrooxalato palladium (II), and a molecular formula of (NH4)2[Pd(NO2)2(C2O4)]·nH2O (n is the number of crystal water). The Pd(II) complex is synthesized by using PdCl2 or [Pd(NH3)2Cl2] as a starting material which is firstly converted into [Pd(NH3)4]Cl2 in ammonium hydroxide, followed by a chemical reaction between [Pd(NH3)4]Cl2 and excessive NaNO2 to produce trans-[Pd(NH3)2(NO2)2] via ligand substitution mechanism, and finally dissolving trans-[Pd(NH3)2(NO2)2] in an aqueous solution of oxalic acid leads to the formation of the target product (NH4)2[Pd(NO2)2(C2O4)]·2H2O. The complex does not contain chlorine and other elements that are harmful to a catalyst, is readily soluble in water and has a low thermal decomposition temperature.

Abstract: A method for separating a calcite-rich low-grade fluorite barite paragenic ore, includes the following steps: S1, crushing; S2, performing classification on a crushed ore to obtain a fine-grained ore, a medium-grained ore and a coarse-grained ore; S3, performing jigging gravity separation on the medium-grained ore and the coarse-grained ore to obtain first barite concentrates and jigging tailings; S4, performing color sorting on the jigging tailings to obtain calcite minerals and color sorting tailings; S5, combining the fine-grained ore and the color sorting tailings, and then performing ore grinding to obtain feeding materials in flotation; S6, performing flotation on the feeding materials in flotation to obtain fluorite concentrates and flotation tailings; S7, performing chute gravity separation on the flotation tailings to obtain second barite concentrates and chute tailings. The method achieves an effect of obtaining high-quality acid-grade fluorite concentrates (CaF2?98%).

Abstract: A method for separating a calcite-rich low-grade fluorite barite paragenic ore, includes the following steps: S1, crushing; S2, performing classification on a crushed ore to obtain a fine-grained ore, a medium-grained ore and a coarse-grained ore; S3, performing jigging gravity separation on the medium-grained ore and the coarse-grained ore to obtain first barite concentrates and jigging tailings; S4, performing color sorting on the jigging tailings to obtain calcite minerals and color sorting tailings; S5, combining the fine-grained ore and the color sorting tailings, and then performing ore grinding to obtain feeding materials in flotation; S6, performing flotation on the feeding materials in flotation to obtain fluorite concentrates and flotation tailings; S7, performing chute gravity separation on the flotation tailings to obtain second barite concentrates and chute tailings. The method achieves an effect of obtaining high-quality acid-grade fluorite concentrates (CaF2?98%).

Abstract: Systems, methods, and devices provide a solar cell module which may ensure a tight connection between a junction box and an external function module. The various embodiments provide a solar cell module having a junction box which may independently support an external function module and may firmly fix the external function module onto a base plate of the solar cell module. The various embodiments simplify the connecting structures between the external function box, the junction box, and the base plate of the solar cell module. The various embodiments provide a solar cell junction box which may enable a solar cell system to track the maximum power point of the solar cell modules in the solar cell system. In an embodiment, a junction box may include a printed circuit board (“PCB”).