Abstract: Disclosed are a catalyst component and a catalyst for olefin polymerization, and an olefin polymerization method. The catalyst component comprises magnesium, titanium, a halogen and an internal electron donor, wherein the internal electron donor comprises a monocarboxylic acid ester compound and a diether compound, and the molar ratio of the monocarboxylic acid ester compound to the diether compound is (0.0035-0.7):1. By using the catalyst, a polymer having both a high isotactic index and a high melt flow index can be prepared.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for jointly training an image embedding model and a text embedding model. In one aspect, a method comprises: processing data from a historical query log of a search system to generate a candidate set of training examples, wherein each training example comprises: (i) a search query comprising a sequence of one or more words, (ii) an image, and (iii) selection data characterizing how often users selected the image in response to the image being identified by a search result for the search query; selecting a plurality of training examples from the candidate set of training examples; and using the training data to jointly train the image embedding model and the text embedding model.

Abstract: A solid component for preparing an olefin polymerization catalyst, and a preparation method therefor and an application thereof are provided. The solid component contains: (i) a magnesium compound as represented by the following formula (1), (ii) a Lewis base (LB), and optionally, (iii) metal components other than magnesium. The LB is a compound as shown in general formula (II) or an amide compound as shown in general formula (II?). The solid component has a better particle morphology, and a catalyst prepared by using the solid component as a carrier is less likely to be crushed, and has better stereostructural orientation in olefin polymerization, particularly in propylene polymerization or copolymerization.

Abstract: A spherical carrier for olefin polymerization catalysts has at least one magnesium-containing compound having a structure represented by formula (1). The spherical carrier has a relatively good particle morphology, and substantially no abnormally morphological particles will appear. A method for preparing the spherical carrier can be used to prepare a carrier having a small particle size and greatly expands the particle size range of the preparable carrier. When the catalyst prepared by using the carrier is used for olefin polymerization, polymerization activity is good, substantially no abnormally morphological material is present, and hydrogen response is good.

Abstract: A copolymer contains, based on the total amount of structural units of the copolymer, 90-99 mol % of propylene structural units and 1-10 mol % of butene structural units. The xylene solubles content of the copolymer is less than or equal to 4 wt %, and preferably less than or equal to 3 wt %. The propylene-butene copolymer is substantially free of fraction having a molecular weight lower than 1000. The copolymer has a melt flow index of greater than or equal to 20 g/10 min as measured at 230° C. under a load of 2.16 kg. The propylene-butene copolymer has a high melt flow index and few xylene solubles, and does not contain a phthalate-type plasticizer, and can be used in fields such as food and medical and health services.

Abstract: A carrier for an olefin polymerization catalyst contains a magnesium-containing compound and sulfur. The sulfur is at least one of an elemental sulfur, a complex sulfur, and a compound sulfur. The carrier has good particle morphology and a smooth surface, and has a narrow particle size distribution. The catalyst prepared from the carrier has high activity and good sensitivity to hydrogen regulation, and can improve the density of a polymer stack when being used for olefin polymerization.

Abstract: Disclosed are a catalyst component and a catalyst for olefin polymerization, and an olefin polymerization method. The catalyst component comprises magnesium, titanium, a halogen and an internal electron donor, wherein the internal electron donor comprises a monocarboxylic acid ester compound and a diether compound, and the molar ratio of the monocarboxylic acid ester compound to the diether compound is (0.0035-0.7):1. By using the catalyst, a polymer having both a high isotactic index and a high melt flow index can be prepared.

Abstract: Spherical carriers for an olefin polymerization catalyst, catalyst components, catalysts, and preparation methods therefor are disclosed. The method for preparing the spherical carriers comprises the following steps: (1) reacting, in the presence of at least one polymeric dispersion stabilizer, a magnesium halide with an organic compound containing active hydrogen to form a complex solution; (2) reacting said complex solution with an alkylene oxide-type compound to directly precipitate solid particles; and (3) recovering the solid particles to obtain spherical carriers. When a catalyst prepared by using the present spherical carrier is used in propylene polymerization, said catalyst exhibits high polymerization activity and high stereo-directing ability.

Abstract: The present invention provides a catalyst component for olefin polymerization and a preparation method thereof, and a catalyst for olefin polymerization and an application thereof. The catalyst component for olefin polymerization comprises reaction products of the following components: (1) a solid component; (2) at least one titanium compound; and (3) at least two internal electron donors, wherein the solid component comprises a magnesium compound represented by formula (1) and an epoxide represented by formula (2), wherein R1 is a C1-C12 linear or branched alkyl; R2 and R3 are identical or different, and are independently hydrogen or unsubstituted or halogen-substituted C1-C5 linear or branched alkyl; X is halogen; m is in a range of from 0.1 to 1.9, n is in a range of from 0.1 to 1.9, and m+n=2.

Abstract: The present invention provides a catalyst component for olefin polymerization and a preparation method thereof, and a catalyst for olefin polymerization and an application thereof. The catalyst component for olefin polymerization comprises reaction products of the following components: (1) a solid component; (2) at least one titanium compound; and (3) at least two internal electron donors, wherein the solid component comprises a magnesium compound represented by formula (1) and an epoxide represented by formula (2), wherein R1 is a C1-C12 linear or branched alkyl; R2 and R3 are identical or different, and are independently hydrogen or unsubstituted or halogen-substituted C1-C5 linear or branched alkyl; X is halogen; m is in a range of from 0.1 to 1.9, n is in a range of from 0.1 to 1.9, and m+n=2.

Abstract: Spherical carriers for an olefin polymerization catalyst, catalyst components, catalysts, and preparation methods therefor are disclosed. The method for preparing the spherical carriers comprises the following steps: (1) reacting, in the presence of at least one polymeric dispersion stabilizer, a magnesium halide with an organic compound containing active hydrogen to form a complex solution; (2) reacting said complex solution with an alkylene oxide-type compound to directly precipitate solid particles; and (3) recovering the solid particles to obtain spherical carriers. When a catalyst prepared by using the present spherical carrier is used in propylene polymerization, said catalyst exhibits high polymerization activity and high stereo-directing ability.

Abstract: A magnesium halide adduct is provided, comprising at least one compound of the formula MgXY, at least one compound of the formula ROH, methanol, at least one modifying agent chosen from DOE and o-hydroxy benzoates, and optionally water. Also provided herein are a catalyst component comprising the magnesium halide adduct, a catalyst for olefin polymerization comprising the catalyst component; the respective processes for preparing the magnesium halide adduct and the catalyst component; use of the magnesium halide adduct for preparing the catalyst component, use of the catalyst component in a catalyst for olefin polymerization and use of the catalyst in olefin polymerization; and a process of olefin polymerization.

Abstract: A magnesium halide adduct is provided, comprising at least one compound of the formula MgXY, at least one compound of the formula ROH, methanol, at least one modifying agent chosen from DOE and o-hydroxy benzoates, and optionally water. Also provided herein are a catalyst component comprising the magnesium halide adduct, a catalyst for olefin polymerization comprising the catalyst component; the respective processes for preparing the magnesium halide adduct and the catalyst component; use of the magnesium halide adduct for preparing the catalyst component, use of the catalyst component in a catalyst for olefin polymerization and use of the catalyst in olefin polymerization; and a process of olefin polymerization.