Petrochina Company Limited

Chinese Academy of Sciences

Beijing Xiaomi Mobile Software Co., Ltd.

Hongming Li

Jianjun Yi

Mingge Zhang

Qigu Huang

Jing Wang

Yuan Yuan

Yong Fan

Tianxu Sun

Yisen Wang

Runcong Zhang

Yanpei Nie

Wei Liu

Shuo Wang

Zhi Peng Liu

Yi Guo

Weisong Cui

Zhibin Zhou

Dianjun Li

Jing Mao

Lin Men

The present invention relates to an olefin coordination polymerization catalyst and a preparation method and application thereof. The olefin polymerization catalyst consists of a primary catalyst mainly prepared from a magnesium compound, a transition metal halide, a C-Calcohol and an electron donor in a molar ratio of 1:1-40:0.01-10:0.001-10, and a co-catalyst which is an organoaluminum compound; and the molar ratio of the transition metal halide to the co-catalyst is 1:10-500. The catalyst of the present invention has a good particle morphology, and a spherical shape, and the catalyst particles do not stick to the vessel wall; the catalyst has high activity and excellent hydrogen regulation performance, and the melt index MFR of polyethylene may be adjusted within 0.01 g/10 min-550 g/10 min; and the catalyst is applicable in slurry polymerization process, loop reactor polymerization process, gas phase polymerization process or combined polymerization process.

Olefin coordination polymerization catalyst, and preparation method and application thereof

The present invention provides an olefin coordination polymerization catalyst and use thereof. The composition of the raw materials of the olefin coordination polymerization catalyst comprises: a main catalyst and a cocatalyst, wherein a molar ratio of the transition metal halide in the main catalyst to the cocatalyst is 1:10-500; and the composition of the raw materials of the main catalyst comprises a magnesium compound, a transition metal halide, an alcohol having 2 to 15 carbon atoms, and a star-shaped organosiloxane compound in a molar ratio of 1:1-40:0.01-10:0.001-10; and the cocatalyst comprises an organoaluminum compound. The above olefin coordination polymerization catalyst is used as a catalyst for ethylene polymerization, propylene polymerization, and copolymerization of ethylene or propylene with an &#x3b1;-olefin. The olefin polymerization catalyst of the present invention has good catalytic activity.

Olefin coordination polymerization catalyst and use thereof

The present disclosure relates to an autofocus testing device. The autofocus testing device includes a first focusing plate; a second focusing plate; a driver configured to drive at least one of a camera and the first and second focusing plates to aim a lens of the camera at the first and second plates in turn, wherein a first distance between the first focusing plate and the camera is different from a second distance between the second focusing plate and the camera; and a controller configured to obtain status information of the driver, determine whether the lens is aimed at one of the first and second focusing plates based on the status information, and control the camera to perform an autofocus image capture operation when the lens is aimed at one of the first and second focusing plates.

Autofocus testing device

The present invention relates to preparation and application of an olefin polymerization catalyst. The main catalyst is composed of a carrier, a transition metal halide, and an organic alcohol compound. The transition metal halide is obtained by in-situ reaction between titanate and silicon halide. The molar ratio of the carrier to the transition metal halide to the organic alcohol compound is 1 to 0.01-20 to 0.1-6. The molar ratio of the titanate to the silicon halide is 1 to 0.5-2. The co-catalyst is an organo-aluminum compound. The molar ratio of the transition metal halide in the main catalyst to the co-catalyst is 1 to 30-500. Particles of the catalyst are good in morphology and are in a spherical shape. The catalyst has high activity and the polymer obtained by using the catalyst has a high molecular weight. The catalyst is applicable to a slurry method, a vapor phase polymerization process, or a combined polymerization process. The preparation method thereof is simple, has low requirements on devices, and produces little pollution on the environment.

Olefin polymerization catalyst and preparation and application thereof

A method for brain tumor segmentation in multi-parametric 3D MR images. The method comprises: pre-processing an input multi-parametric 3D MR image; classifying each voxel in the pre-processed multi-parametric 3D MR image, determining the probability that the voxel is part of a brain tumor, and obtaining an initial label information for the image segmentation based on the classification probability; constructing a graph based representation for the pre-processed image to be segmented; and generating the segmented brain tumor image using the initial label information and graph based representation. This method tries to exploit the local and global consistency of the image to be segmented for the tumor segmentation and can alleviate partially the performance degradation caused by the inter-subject image variability and insufficient statistical information from training.

Method and system for brain tumor segmentation in multi-parameter 3D MR images via robust statistic information propagation

A method for brain tumor segmentation in multi-parametric 3D magnetic resonance (MR) images, comprising: determining, for each voxel in the multi-parametric 3D MR image sequence, a probability that the voxel is part of brain tumor; extracting multi-scale structure information of the image; generating multi-scale tumor probability map based on initial tumor probability at voxel level and multi-scale structure information; determining salient tumor region based on multi-scale tumor probability map; obtaining robust initial tumor and non-tumor label based on tumor probability map at voxel level and salient tumor region; and generating a segmented brain tumor image using graph based label information propagation. The present invention is capable of achieving statistical reliable, spatially compact, and robust tumor label initialization, which is helpful to the accurate and reliable tumor segmentation. And the label information propagation framework could partially alleviate the performance degradation caused by image inconsistency between images to be segmented and training images.

Method for brain tumor segmentation in multi-parametric image based on statistical information and multi-scale structure information

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Beijing, China

Hongming Li