52results about How to "Negligible cost" patented technology

The invention discloses a method for extracting and purifying microcystin, in particular a method for extracting high-purity microcystin MC-RR and MC-LR from a raw material of dried powder of bloom cyanobacteria harvested in the field. The method comprises the following steps of: A, crudely extracting the microcystin MC-RR and MC-LR by using methanol; B, making the crude extracting solution pass through an ODS column to finely extract the microcystin MC-RR and MC-LR; C, separating the microcystin MC-RR from MC-LR by using a semi-preparative chromatograph; and D, saving the microcystin MC-RR and MC-LR. The method for extracting and purifying the microcystin has the advantages of wide sources of raw materials, low cost, simple operating process, purity of over 97 percent of the extracted microcystin, and capacity of meeting the requirement on toxin purity for scientific research.

The invention discloses a seam structure of a prefabricated sectional type concrete bridge and belongs to the field of bridge engineering. On the basis that a conventionally-used formwork is basically not changed, protruding blocks and corresponding grooves are prefabricated at the two ends of each section, and hole channels of connecting reinforcing steel bars are reserved in each protruding block. After the sections are spliced, the connecting reinforcing steel bars penetrate into the reserved hole channels and anchored. The section connecting portions are squeezed tightly, a seam between the prefabricated sections is high in shearing strength, the bending performance of a bridge body is enhanced, and cracking of the bottom of the seam is delayed. Even though a crack appears, the crack can be effectively prevented from being expanded through the connecting reinforcing steel bars, and therefore the bearing capacity of the bridge body is improved. Compared with the prior art, the structure is convenient to construct, the integrality of the bridge established through the structure is good, and the mechanical property of the seam is greatly improved.

The invention claims a multifunctional circulating packaging box which is provided with a RFID identification card and is capable of overcoming such disadvantages of RF cards in the prior art that the price is high, the identification rate is low and wide use in the storage physical distribution management is not possible. The multifunctional circulating packaging box adopts the technical proposal that: the circulating packaging box comprises a top cover, a front panel, a back panel, two side plate composite members and a base board, wherein, the two side plate composite members comprise at least one intermediate plate and side plates symmetrically arranged on two sides of the intermediate plate. The circulating packaging box is characterized in that the front panel is inserted with a passive tag, or / and the side plates are provided with at least one of active tag or semi-passive tag. The application of the circulating packaging box in the storage physical distribution management on one hand saves the operation cost for manufacturers, importers and vendors, and on the other hand improves the efficiency of goods counting and the accuracy of the identification, thus greatly improving the intelligent management level of physical distribution, storage and relative trades.

The invention relates to a preparation method of metal nanometer powder, in particular to a nanometer iron powder special for shielding electromagnetic wave and radar wave in a glass cockpit of an airplane. The nanometer iron powder solves the problem that the existing nanometer metal powder can not completely shield the electromagnetic wave and the radar wave in the glass cockpit of the airplane. The preparation method comprises the steps of: machining raw materials into nanometer iron powder which has the shape of spheriform powder grain and has special stealth technology under the conditions that the temperature is -5 to 0 DEG C and the high-frequency cutting times is 5500-6000 times / minute; respectively screening out the powder material with centralized grain distribution with D3=21nm, D25=22.1nm, D50=25nm, D75=27.2nm and D97=30.3nm; and packaging in an anti-oxidation way, processing a surface and filling magnetism. The nanometer iron powder solves the problems of the film coating of an ion metallic coating reflecting film and the maintaining when in use, and can block the electromagnetic wave radiation between instruments of the airplane and the external part of a cockpit of the air such as equipment of aviators.

The invention discloses a combined optimization method for protection locking based on busbar protection and quick-cutting device for high power plants, which belongs to the field of relay protection for power plant generator-transformer units. Solve the defect that the quick-cut device cannot be locked after the protection action of the high-voltage plant busbar, causing the quick-cut device to close the high-voltage backup circuit breaker to the faulty busbar. In this method, the secondary tripping circuits of the high-voltage working incoming line circuit breaker and the high-voltage standby incoming line circuit breaker for busbar protection are firstly optimized and transformed, and the closing command of the high-voltage standby incoming line circuit breaker of the blocking fast-cutting device after the busbar protection action is realized and self-maintained ; At the same time, optimize the abnormal voltage blocking logic of the fast switching device, and increase the bus fault judgment logic to block the fast switching device. The invention only needs to add a small amount of secondary equipment and reform part of the circuit, and modify the software logic and fixed value of the fast cutting device to realize it, which is simple and easy.