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A Tracking Registration Method for Augmented Reality Based on Multi-modal Template matching and Point Clouds

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International Journal of Automation and computing 2021年第2期18卷 288-299页

作者： Peng-Xia Cao Wen-Xin Li Wei-ping ma Lanzhou Institute of Physics China Academy of Space TechnologyLanzhou 730000China

In order to overcome the defects where the surface of the object lacks sufficient texture features and the algorithm cannot meet the real-time requirements of augmented reality,a markerless augmented reality tracking registration method based on multimodal template matching and point clouds is *** method first adapts the linear parallel multi-modal LineMod template matching method with scale invariance to identify the texture-less target and obtain the reference image as the key frame that is most similar to the current ***,we can obtain the initial pose of the camera and solve the problem of re-initialization because of tracking registration interruption.A point cloud-based method is used to calculate the precise pose of the camera in real *** order to solve the problem that the traditional iterative closest point(ICP)algorithm cannot meet the real-time requirements of the system,Kdtree(k-dimensional tree)is used under the graphics processing unit(GPU)to replace the part of finding the nearest points in the original ICP algorithm to improve the speed of tracking *** the same time,the random sample consensus(RANSAC)algorithm is used to remove the error point pairs to improve the accuracy of the *** results show that the proposed tracking registration method has good real-time performance and robustness.

关键词： Augmented reality markerless tracking registration LineMod iterative closest point(ICP)algorithm

ShRNA-mediated gene silencing of β-catenin inhibits growth of human colon cancer cells

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World Journal of Gastroenterology 2007年第48期13卷 6581-6587页

作者： Wen-Sheng Huang Jian-ping Wang Ting Wang Jie-Yu Fang ping Lan Jin-ping ma Surgery Department The First Affiliated Hospital Sun Yat-sen University Guangzhou 510080 Guangdong Province China

AIM: To observe the gene silencing mediated by the specific shRNA targeted against β-catenin and its effect on cell proliferation and cycle distribution in the human colon cancer cell line Colo205. METHODS: Two shRNA plasmid vectors against β-catenin were constructed and transfected into Colo205 cells with LipofectamineTM2000. The down-regulations of β-catenin, c-myc and cyclinD1 expressions were detected by RT-PCR and western blot analysis. The cell proliferation inhibitions were determined by MTT assay and soft agar colony formation assay. The effect of these two β-catenin shRNAs on cell cycle distribution and apoptosis was examined by flow cytometry. RESULTS: These two shRNA vectors targeted against β-catenin efficiently suppressed the expression of β-catenin and its down stream genes, c-myc and cyclinD1. The expression inhibition rates were around 40%-50% either at the mRNA or at the protein level. The shRNA-mediated gene silencing of β-catenin resulted in significant inhibition of cell growth both on the culture plates and in the soft agar. Moreover, the cancer cells showed significant G0/G1 arrest and increased apoptosis at 72 h post transfection due to gene silencing. CONCLUSION: These specific shRNAs targeted against β-catenin could have a gene silencing effect and block the WNT signaling pathway. They could inhibit cell growth, increase apoptosis, and induce cell cycle arrest in Colo205 cells. ShRNA interference against β-catenin is of potential value in gene therapy of colon cancer.

关键词： β-catenin RNA interference Apoptosis Colon cancer WNT

Binocular Vision Object Positioning Method for Robots Based on Coarse-fine Stereo matching

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International Journal of Automation and computing 2020年第4期17卷 562-571页

作者： Wei-ping ma Wen-Xin Li Peng-Xia Cao Lanzhou Institute of Physics China Academy of Space TechnologyLanzhou 730000China

In order to improve the low positioning accuracy and execution efficiency of the robot binocular vision,a binocular vision positioning method based on coarse-fine stereo matching is proposed to achieve object *** random fern is used in the coarse matching to identify objects in the left and right images,and the pixel coordinates of the object center points in the two images are calculated to complete the center *** the fine matching,the right center point is viewed as an estimated value to set the search range of the right image,in which the region matching is implemented to find the best matched point of the left center ***,the similar triangle principle of the binocular vision model is used to calculate the 3D coordinates of the center point,achieving fast and accurate object ***,the proposed method is applied to the object scene images and the robotic arm grasping *** experimental results show that the average absolute positioning error and average relative positioning error of the proposed method are 8.22 mm and 1.96%respectively when the object's depth distance is within 600 mm,the time consumption is less than *** method can meet the needs of the robot grasping system,and has better accuracy and robustness.

关键词： Object positioning stereo matching random fern normalized cross correlation binocular vision model

Tracking Registration Algorithm for Augmented Reality Based on Template Tracking

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International Journal of Automation and computing 2020年第2期17卷 257-266页

作者： Peng-Xia Cao Wen-Xin Li Wei-ping ma Lanzhou Institute of Physics China Academy of Space TechnologyLanzhou 730000China

Tracking registration is a key issue in augmented reality applications,particularly where there are no artificial identifier placed *** this paper,an efficient markerless tracking registration algorithm which combines the detector and the tracker is presented for the augmented reality *** capture the target images in real scenes as template images,use the random ferns classifier for target detection and solve the problem of reinitialization after tracking registration failures due to changes in ambient lighting or occlusion of *** the target has been successfully detected,the pyramid Lucas-Kanade(LK)optical flow tracker is used to track the detected target in real time to solve the problem of slow *** least median of squares(LMedS)method is used to adaptively calculate the homography matrix,and then the three-dimensional pose is estimated and the virtual object is rendered and *** results demonstrate that the algorithm is more accurate,faster and more robust.

关键词： Tracking registration augmented reality markerless random ferns Lucas-Kanade(LK)optical flow

Formation of six-coordinated silicon in calcium phosphosilicate xerogels assisted by polyols at low temperature and pressure

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Chinese Chemical Letters 2015年第6期26卷 768-772页

作者： Ai-Ling Li Yan-ping ma Dong Qiu Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of Sciences

Silicon is usually found to be four-coordinated when neighbored with oxygen. Six-coordinated silicon is only seen in samples at very specific composition or made at high temperature/pressure. In this study, we managed to synthesize calcium phosphosilicate xerogels containing six-coordinated silicon with the help of polyols by sol-gel method, without the need of treatment at high temperature or high pressure. Both phosphorus precursors and polyols were found to be essential for the formation of six-coordinated silicon species; in the absence of either species, only normal four-coordinated silicon was observed under otherwise identical conditions. Samples containing six-coordinated silicon sites were found to release silicon species faster than those without six-coordinated silicon sites upon dissolved in water, suggesting that six-coordinated silicon species have higher reactivity toward hydrolysis.

关键词： Phosphosilicate Six-coordinated silicon PolyolsmaS-NMR

Solvent Vapor Annealing Induced Polymorphic Transformation of Polybutene-1

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Chinese Journal of Polymer Science 2016年第9期34卷 1141-1149页

作者： hua-feng shao ya-ping ma 聂华荣贺爱华 Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics (Ministry of Education) School of Polymer Science and Engineering Qingdao University of Science and Technology Qingdao 266042 China

Solvent annealing is a facile method for changing the aggregated microstructure and physical properties of polymer materials. In this paper, we addressed the effects of solvent vapor annealing, including chloroform and water vapor, on the polymorphic transformation in both hot-pressed film and electrospun nonwoven of isotactic polybutene-1 （PB-1） by means of in situ Fourier transform infrared spectroscopy （FTIR）. The pretty rapid transition rate caused by the increased motion of molecular chains under chloroform vapor is associated with a lowest crystallinity. Also, a decreased crystallinity with the crystal transition occurred in electrospun nonwovens resulting from the relaxation of the stretched molecular chains into amorphous state rather than realignment into crystal form I predominating the crystal transition process.

关键词： Polybutene-1 Crystal transformation Solvent vapor annealing.

Differential Polymorphic Transformation Behavior of Polybutene-1 with Multiple Isotactic Sequences

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Chinese Journal of Polymer Science 2020年第2期38卷 164-173,I0007页

作者： Ya-ping ma Wei-ping Zheng Chen-Guang Liu Hua-Feng Shao Hua-Rong Nie Ai-Hua He Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics (Ministry of Education) Qingdao University of Science and Technology

For the solid-solid transformation from form Ⅱ to form Ⅰ of isotactic polybutene-1(iPB),the temperature dependence of form Ⅰ nucleation and growth was deemed to control the transformation ***,the relationship between formⅠ formation and form Ⅱ disappearance in the transformation process is not *** this work,the spontaneous crystal transformation from form Ⅱ to Ⅰ of iPB with 81 mol%mmmm sequence concentration is studied firstly by tracking the two processes,the decay of form Ⅱ and the yielding of form Ⅰ in a wide range of temperature spanning from 0℃ to 50℃ and in a long transformation time ranging from 5 min to 65 days with in situ FTIR and *** the literature reports,the decay rate of form Ⅱ is firstly found to be lower than the yielding rate of form Ⅰ at all studied temperatures,especially at low transition *** is attributed to the amorphous chains which locate near crystal lamella participating into the nucleation of form Ⅱ.The regular chain folding and growth of i PB form Ⅰ from amorphous chains containing short isotactic sequences also lead to an increase in crystallinity of form Ⅰ compared with that of initial form Ⅱ crystallized at 60℃.An increase in the annealing temperature results in decrease in crystallinity and increase in lamellae thickness of i PB formⅠ.

关键词： Polybutene-1 Polymorphic transformation Isotactic sequence Crystallinity Lamellae thickness

Polymerization Kinetics of Propylene with the MgCl_(2)-Supported Ziegler-Natta Catalysts——Active Centers with Different Tacticity and Fragmentation of the Catalyst

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Chinese Journal of Polymer Science 2021年第1期39卷 70-80,I0006页

作者： Wei-ping Zheng Ya-ping ma Da-Lin Du Ai-Hua He Hua-Feng Shao Chen-Guang Liu Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics(Ministry of Education)School of Polymer Science and EngineeringQingdao University of Science and TechnologyQingdao 266042China

The catalytic activity and stereospecificity of olefin polymerization by using heterogeneous TiCl_(4)/MgCl_(2) Ziegler-Natta(Z-N) catalysts are determined by the structure and nature of active centers, which are mysterious and fairly controversial. In this work, the propylene polymerization kinetics under different polymerization temperatures by using Z-N catalysts were investigated through monitoring the concentration of active centers [C*] with different tacticity. SEM was applied to characterize the catalyst morphologies and growing polypropylene(PP) particles. The lamellar thickness and crystallizability of PP obtained under different polymerization conditions were analyzed by DSC and SAXS. The PP fractions and active centers with different tacticity were obtained with solvent extraction fractionation method. The catalytic activity, active centers with different tacticity and propagation rate constant kp, fragmentation of the catalyst, crystalline structure of PP are correlated with temperature and time for propylene polymerizations. The polymerization temperature and time show complex influences on the propylene polymerization. The higher polymerization temperature(60 ℃) resulted higher activity, kp and lower [C*], and the isotactic active centers Ci* as the majority ones producing the highest isotactic polypropylene(iPP) components showed much higher kp when compared with the active centers with lower stereoselectivity. Appropriate polymerization time provided full fragmentation of the catalyst and minimum diffusion limitation. This work aims to elucidate the formation and evolution of active centers with different tacticity under different polymerization temperature and time and its relations with the fragmentation of the PP/catalyst particles, and provide the solutions to the improvement of catalyst activity and isotacticity of PP.

关键词： Polypropylene Catalytic activity Active center Catalyst fragmentation

High laser damage threshold coatings and damage testing technology

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光学精密工程 2005年第4期13卷 500-504页

作者： ma ping HU Jian-ping CHEN Song-lin TANG Ming WANG Zhen LI Wei XU Qiao Chengdu Fine Optical Engineering Research Center Chengdu 610041China

The laser-induced damage threshold(LIDT) of optical coating is a limited factor for development of a high peak power laser. The automatic damage testing facility was built to determine the LIDT of optics at 1 064 nm and 355 nm.. The cleanning and processing procedure of the substrate and coating technique were improved, and the damage resistance of high-reflective coating at 1 064 nm was increased.

关键词：激光涂覆技术 LIDT 自动机械光学仪器激光仪器