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Infinitesimal nonrigidity of convex surfaces with planar boundary 被引量:1
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作者 LI Chunhe HONG Jiaxing 《Science China Mathematics》 SCIE 2005年第4期513-521,共9页
In the present paper infinitesimal nonrigidity of a class of convex surfaces with planar boundary is given. This result shows that if the image of the Gauss map of an evolution convex surface with planar boundary cove... In the present paper infinitesimal nonrigidity of a class of convex surfaces with planar boundary is given. This result shows that if the image of the Gauss map of an evolution convex surface with planar boundary covers some hemisphere, this surface may be of infinitesimal nonrigidity for the isometric deformation of planar boundary. 展开更多
关键词 INFINITESIMAL nonrigidity CONVEX surface PLANAR boundary.
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Theoretical Exploration of Stereochemical Nonrigidity for RfCo(PF3)x(CO)4-x(Rf=CF3, C2F5, C3F7, x=0-4)
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作者 LIU Tingting LU Xi ZHANG Mingtao 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2014年第4期656-660,共5页
The stereochemical nonrigidity of RfCo(PF3)x(CO)4-x(Rf=CF3,C2F5,C3F7,x=0-4) was studied at the theoretical level of B3LYP/6-31 1+G^* via Gaussian 09.The intramolecular rearrangements in these penta-coordinated... The stereochemical nonrigidity of RfCo(PF3)x(CO)4-x(Rf=CF3,C2F5,C3F7,x=0-4) was studied at the theoretical level of B3LYP/6-31 1+G^* via Gaussian 09.The intramolecular rearrangements in these penta-coordinated compounds are mainly caused by the vibrations of perfluoroalkyl groups.All the barriers along the reaction coordinate are less than 66.9 kJ/mol,which indicates that the rearrangements are kinetically favorable and hard to elucidate by experiment.Besides,ligand PF3 is a ligand similar to CO,the energy difference between the reactant and product is small. 展开更多
关键词 Density functional theory(DFT) Intramolecular rearrangement Stereochemical nonrigidity Pentacoordination
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Tremor Suppression Method via Magnetorheological Damper and Fuzzy Neural Network Control
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作者 李军强 臧希喆 赵杰 《Journal of Donghua University(English Edition)》 EI CAS 2010年第4期486-490,共5页
Based on the performance of magnetorheological damper we have developed,a tremor suppression method using human limb nonrigid characteristic was presented.The tremor suppression machine was designed,and the measure pa... Based on the performance of magnetorheological damper we have developed,a tremor suppression method using human limb nonrigid characteristic was presented.The tremor suppression machine was designed,and the measure part and the tremor suppression part were separated.Subsequently,the mathematic models of fuzzy neural network and elbow nonrigid tremor were worked out.Using selected training data set,the off-line fuzzy neural network training was finished.Then the tremor suppression method was simulated in Matlab.From the simulation results,it is found that the tremor suppression method has presented suppresses tremor effectively,and the tremor amplitude and tremor suppression torque can be controlled with angle displacement sensor. 展开更多
关键词 magnetorheological damper nonrigid body fuzzy neural network tremor suppression
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A diffusion-weighted imaging based diagnostic system for early detection of prostate cancer
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作者 Ahmad Firjani Ahmed Elnakib +4 位作者 Fahmi Khalifa Georgy Gimel’farb Mohamed Abou El-Ghar Adel Elmaghraby Ayman El-Baz 《Journal of Biomedical Science and Engineering》 2013年第3期346-356,共11页
A new framework for early diagnosis of prostate cancer using Diffusion-Weighted Imaging (DWI) is proposed. The proposed diagnostic approach consists of the following four steps to detect locations that are suspicious ... A new framework for early diagnosis of prostate cancer using Diffusion-Weighted Imaging (DWI) is proposed. The proposed diagnostic approach consists of the following four steps to detect locations that are suspicious for prostate cancer: 1) In the first step, we isolate the prostate from the surrounding anatomical structures based on a Maximum A Posteriori (MAP) estimate of a new log-likelihood function that accounts for the shape priori, the spatial interaction, and the current appearance of prostate tissues and its background (surrounding anatomical structures);2) In order to take into account any local deformation between the segmented prostates at different b-values that could occur during the scanning process due to local motion, a non-rigid registration algorithm is employed;3) A KNN-based classifier is used to classify the prostate into benign or malignant based on three appearance features extracted from registered images;and 4) The tumor boundaries are determined using a level set deformable model controlled by the diffusion information and the spatial interactions between the prostate voxels. Preliminary experiments on 28 patients (17 malignant and 11 benign) resulted in 100% correct classification, showing that the proposed method is a promising supplement to current technologies (biopsy-based diagnostic systems) for the early diagnosis of prostate cancer. 展开更多
关键词 PROSTATE Cancer 3D Markov-Gibbs RANDOM Field Nonrigid REGISTRATION DIFFUSION-WEIGHTED Imaging
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Approach to Nonrigid Body Metamorphosis Using Generalized Morph-translation
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作者 Liu Wengu Li Hua Thu Guangxi (Department of Electronics & Information Engineering Huazhong University of Science & Technology Wuhan, Hubei 430074, P R. China ) 《Computer Aided Drafting,Design and Manufacturing》 2000年第1期1-8,共8页
An approach of morphing by decomposing two objects into sets of individual convex sub objects respectively and contructing the mapping between two sets is presented The Minkvski addition of two convex sub-objects acco... An approach of morphing by decomposing two objects into sets of individual convex sub objects respectively and contructing the mapping between two sets is presented The Minkvski addition of two convex sub-objects according to their mapping ralationship is calculated, then all the Minkovski additions are combined to obtain the final result. Nonrigid body motion can be divided into nonrigid body metamorphosis and rigid body rotation A novel method for describing nonrigid body motion based on generalized morph-translation is proposed. This method can solve the metamorphosis problem of two non-homotopic objects. Experiments show tha this method can generate natural, high quality metamorphosis results with simple computation. This method can also be used in interpolation between two keyframes in 2D and 3D computer animation automatically. 展开更多
关键词 minkovski addition generalized morph-translation nonrigid body metamorphosis
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A TV-l_1 Based Nonrigid Image Registration by Coupling Parametric and Non-parametric Transformation
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作者 Wen-Rui Hu Yuan Xie +1 位作者 Lin Li Wen-Sheng Zhang 《International Journal of Automation and computing》 EI CSCD 2015年第5期467-481,共15页
To overcome the conflict between the global robustness and the local accuracy in the dense nonrigid image registration,we propose a union registration approach using a l1-norm based term to couple the parametric trans... To overcome the conflict between the global robustness and the local accuracy in the dense nonrigid image registration,we propose a union registration approach using a l1-norm based term to couple the parametric transformation and the non-parametric transformation. On one hand, we take the parametric deformation field as a constraint for the non-parametric registration, which is a strong constraint that guarantees the robustness of the non-parametric registration result. On the other hand, the non-parametric deformation field is taken as a force to improve the accuracy of the parametric registration. Then, an alternating optimization scheme is carried out to improve the accuracy of both the parametric registration and the non-parametric registration. Moreover, accounting for the effect of spatially-varying intensity distortions and the sparse gradient prior of the deformation field, we adopt the residual complexity(RC) as the similarity metric and the total variation(TV) as the regularization. Because of the TV-l1-l2 composite property of the objective function in our union image registration, we resort to the split Bregman iteration for the complex problem solving. Experiments with both synthetic and real images in different domains illustrate that this approach outperforms the separately performed parametric registration or non-parametric registration. 展开更多
关键词 Nonrigid registration free-form deformation non-pa
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