35results about How to "Reduce or avoid the formation of" patented technology

A guanidine oligomer, a method for preparing same, and an application of the guanidine oligomer for being bonded to a molecular chain of a universal polymer. Compared with the prior art, a non-polar long-chain aliphatic R group structure is used for end-capping to obtain a guanidine oligomer end-capped with R which is -(CH2)4-18CH3. There are two extremely favorable results for doing this. First, due to the end-capping with the R group, the original tetrafunctionality is reduced to bifunctionality; during a bonding reaction with a polymer, no cross-linked structure would be formed, but an overhanging structure on a molecular chain is formed; and this is favorable for dispersion on the surface of a material. Moreover, due to the non-polar long-chain aliphatic R group structure, it is easy to achieve distribution on the surface in a non-polar polyolefin, so as to pull the molecular chain of the guanidine oligomer toward the surface and exerting its functionalization. The guanidine oligomer can be widely used in the fields of universal high / low molecular weight polyolefins and universal condensation polymers, and make the universal high / low molecular weight polyolefins and universal condensation polymers antistatic, easy to dye, and resistant to harmful microorganisms.

The invention discloses a preparation method of a samarium-iron-nitrogen series permanent magnet material. The method comprises the steps that metastable state samarium-iron alloy is subjected to severe plastic deformation and then is subjected to nitrogen treatment and annealing crystallization treatment, and therefore the samarium-iron-nitrogen series permanent magnet material can be obtained. In the method, when the deformed samarium-iron-nitrogen series permanent magnet material is subjected to nitrogen treatment, since the free volume 'defect' content in the metastable state alloy can beincreased through multiple shear bands produced in the severe plastic deformation process, entering and diffusion of nitrogen atoms are facilitated, and the nitriding amount and nitriding uniformity of the alloy can be remarkably improved; since the multiple shear bands are produced through the severe plastic deformation, the follow-up crystallization annealing temperature can also be reduced, andnitride is reduced or prevented from being produced; and generation of the metastable phase is restrained, grains are refined, and coercive force is improved. By means of the method, the nitriding speed can be improved, the nitriding temperature can be reduced, decomposition of a samarium-iron-nitrogen compound is restrained, the microstructure is refined, and the nitriding efficiency of samarium-iron alloy for preparing the samarium-iron-nitrogen magnetic material is improved.

The present invention relates to a composition comprising one or more of bacterial strains, wherein the one or more of bacterial strains exhibit a stronger inhibition of pathogenic C. acnes strains compared to non-pathogenic C. acnes strains.

The invention relates to an online process for improving the impact toughness of a welding heat affected zone. The online process adopts the technical scheme that the compressed gas is directly blown at the position of a welding joint which is 20-1200 mm away from a welding electric arc in the welding process of a steel product; the blowing time is 2-120 s; and the distance between the position of the blown welding joint and the welding electric arc is kept unchanged and synchronously moves forwards along with the welding electric arc. The compressed gas is air, the pressure of the compressedgas is 0.5-3.0 MPa; the flow rate of the compressed gas is 5-30 L / min; the steel product is one of low carbon steel, medium carbon steel, low alloy steel, medium alloy steel and high alloy steel; andthe welding joint is one of welding points formed by welding methods of electric arc welding, submerged-arc welding, gas shielded welding and argon tungsten-arc welding. The online process has the characteristics that the online process is simple, is convenient to operate, has low cost and requires no additionally-arranged special equipment. With the adoption of the process, the impact toughness of the welding heat affected zone can be improved by 60-525 percent.

The invention provides a method for nitridation and crystallization of metastable-state samarium-iron alloy. The method comprises the steps of performing rapid cooling and sudden condensation on molten-state samarium-iron alloy to obtain the metastable-state samarium-iron alloy; performing nitridation and initial crystallization on the metastable-state samarium-iron alloy to obtain nitrided samarium-iron alloy; and performing annealing and crystallization on the nitrided samarium-iron alloy to obtain a samarium-iron nitrogen permanent-magnet material. During nitridation of a metastable-state material, a large amount of rheological units existing in the metastable-state alloy are beneficial for diffusion and homogenization of nitrogen atoms, the nitridation content of the alloy can be remarkably increased, and the nitrogen atoms are uniformly distributed; crystallization is completed before decomposition of Sm<2>Fe<17>N<x>, nitride formation is reduced or prevented, and the metastable-state samarium-iron alloy has a refined microstructure; and moreover, according to the method provided by the invention, the nitridation speed is fast, and the nitridation efficiency of improving a samarium-iron nitrogen magnetic material by the samarium-iron alloy is improved.

The invention relates to an occluder and a preparation method thereof. The occluder includes a supporting net, and the surface of the supporting net is coated with an antithrombotic film, and the antithrombotic film includes an endothelialization promoting film; the endothelializing promoting film contains a degradable polymer and an endothelializing substance dispersed in the degradable polymer. Alternatively, the endothelialization-promoting membrane contains endothelialization-promoting substances, and the antithrombotic membrane further includes a controlled-release membrane covering the endothelialization-promoting membrane, and the controlled-release membrane contains degradable polymers. The occluder can reduce or avoid thrombus formation.

The invention discloses a system for quantitatively calculating concrete pouring voids during the secondary lining construction period of tunnels. The system includes: a plurality of detection units, each detection unit detects the height of the concrete pouring surface, and generates a pouring height representing the concrete The electrical signal; the judgment unit, which receives multiple electrical signal data, and processes each electrical signal data to obtain the height data of the monitoring points distributed according to a certain density on the concrete pouring surface during the secondary lining construction period, and according to these heights data to calculate the volume of unfilled voids above the concrete surface and below the flashing. The invention effectively solves the problem of unclear pouring state of the concrete during the secondary lining construction period, can provide reliable judgment basis for construction personnel, guarantee the quality of lining construction, and reduce or avoid the formation of cavities from the source.

A hygienic seal for a container comprising a circular upper cover (1) and a lower ring (2) connected to the upper cover (1) and capable of being fitted around the body of the container , the upper cover has an extension protruding outwards and pointing towards the lower ring (2), so that in the closed state of the container, the extension of the upper cover (1) is in contact with the The lower ring (2) described above partially overlaps. A positioning device is provided on the upper flange of the lower ring (2), and the positioning device includes at least one recessed part, which is complementary to the protrusion protruding inward from the inner surface of the extension part, toward the The inner surface of the extension part of the lower ring (2) has a locking device, and when the container is in a closed state and the protrusion and the recess are in contact with each other, the locking device can be in contact with the lower ring ( 2) contact.