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Needle Deflection during Insertion into Soft Tissue Based on Virtual Spring Model
Haiyan Du,Yongde Zhang,Jingang Jiang,Yanjiang Zhao 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.1
Needle insertion is the most common procedure of minimally invasive interventions. During insertion into a soft tissue, the needle with bevel tip can deflect due to the asymmetric forces acting on the tip of the needle. In this paper, a mechanics-based model is developed to predict the needle deflection. In the model, the needle is considered as a cantilever beam supported by a series of nonlinear springs each of which has stiffness different from each other. The value of stiffness can be calculated by cutting force acting on the needle tip. Based on the model and the analysis of cutting force and friction force, Rayleigh-Ritz method is used to estimate the amount of needle deflection. Experiment shows that the simulation model can accurately predict the deflection of the bevel-tipped needle.
Improved Multi-objective Genetic Algorithm Based on Parallel Hybrid Evolutionary Theory
Zou Yingyong,Zhang Yongde,Li Qinghua,Jiang Jingang,Yu Guangbin 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.1
Based on the analysis on the basic principles and characteristics of the existing multi-objective genetic algorithm (MOGA), an improved multi-objective GA with elites maintain is put forward based on non-dominated sorting genetic algorithm (NSGA). NSGA-II algorithm theory and parallel hybrid evolutionary theory is described in detail. The design principle, process and detailed implementations of the improved MOGA are given. IMNSGA-II algorithm and NSGA-II algorithm are applied to test the performance of the two algorithms for different test function, experiments of example are preformed. Experimental results show that the improved MOGA achieved the optimal between the convergence and diversity.
Simulation and Analysis of Orthodontic Archwire Bending Robot
Yongde Zhang,Xiaohong Jia,Jingang Jiang,Yi Liu,Yong Wang 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.8
A 3D mathematical model of orthodontic archwire with rectangular curve is established. Simplified 3D solid model of orthodontic archwire bending robot, which is consistent of bending die, support structure and archwire are established by Creo software, then the simplified model of bending die is put into ANSYS Workbench. Material parameters the contact condition and boundary conditions are set reasonably for the model. Based on the finite element analysis method, the calculation and analysis of the nonlinear contact problem of archwire and bending die, besides the stress distribution of curve bending and bending die is got. This provides the reference for optimal design of bending planning and bending die.
MRI Segmentation of a Prostate Based on Distance Regularized Level Set Evolution with a Priori Shape
Jingchun Peng,Yongde Zhang,Gang Liu,Jingang Jiang,Yanjiang Zhao 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.11
Prostate segmentation from MRI is a necessary first step and plays a key role in different stages of clinical decision making process. In this paper, we propose a MR T1 Image segmentation method of the prostate based on distance regularized level set evolution with a deformable shape prior. To smooth the prostate image to reduce the noise, we introduce a prostate image with Gaussian kernel and get an edge indicator. To avoid the leakage induced on account of prostate boundaries missing, or blending with surrounding tissues, we introduce priori shape information to construct an energy function with a distance regularization term and an external shape energy term containing the edge indicator and minimize it by solving the gradient flow which can be implemented with a finite difference scheme. To verify the MRI segmentation method of a prostate presented in this paper, we utilize the optimal value of parameters λ, μ, α and ε in the distance regularized level set evolution model and the deformable shape prior of prostate to segment a part of images from normal prostate, benign hyperplasia prostate and cancer prostate. The experiment results show that the MRI segmentation method of prostate presented in this paper is effective for different situation of different patients.
Neutronic design and evaluation of the solid microencapsulated fuel in LWR
Deng Qianliang,Li Songyang,Wang Dingqu,Liu Zhihong,Xie Fei,Zhao Jing,Liang Jingang,Jiang Yueyuan 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8
Solid Microencapsulated Fuel (SMF) is a type of solid fuel rod design that disperses TRISO coated fuel particles directly into a kind of matrix. SMF is expected to provide improved performance because of the elimination of cladding tube and associated failure mechanisms. This study focused on the neutronics and some of the fuel cycle characteristics of SMF by using OpenMC. Two kinds of SMFs have been designed and evaluated - fuel particles dispersed into a silicon carbide matrix and fuel particles dispersed into a zirconium matrix. A 7x7 fuel assembly with increased rod diameter transformed from the standard NHR200-II 9x9 array was also introduced to increase the heavy metal inventory. A preliminary study of two kinds of burnable poisons (Erbia & Gadolinia) in two forms (BISO and QUADRISO particles) was also included. This study found that SMF requires about 12% enriched UN TRISO particles to match the cycle length of standard fuel when loaded in NHR200-II, which is about 7% for SMF with increased rod diameter. Feedback coefficients are less negative through the life of SMF than the reference. And it is estimated that the average center temperature of fuel kernel at fuel rod centerline is about 60 K below that of reference in this paper