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Search Results: 1 - 10 of 167339 matches for " WANG Yan-feng "
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Biodegradable and bioactive porous polyurethanes scaffolds for bone tissue engineering  [PDF]
Mei-Na Huang, Yuan-Liang Wang, Yan-Feng Luo
Journal of Biomedical Science and Engineering (JBiSE) , 2009, DOI: 10.4236/jbise.2009.21007
Abstract: Biodegradable porous polyurethanes scaffold have themselves opportunities in service, in-cluding controlled degradation rate, no-toxic degradation products. However, polyurethanes are lack of bioactive groups, which limits their application. This review gives the common modification methods, surface functionalization and blending modification. In finally, the review puts forward to the bulk modification as a new method to enhance the bioactivity of polyure-thanes.
Two-dimensional ternary locally resonant phononic crystals with a comblike coating
Yan-Feng Wang,Yue-Sheng Wang,Litian Wang
Physics , 2013, DOI: 10.1088/0022-3727/47/1/015502
Abstract: Two-dimensional ternary locally resonant phononic crystals used to consist of cylindrical scatterers with uniform coatings in their exterior. An alternative coating scheme with a comblike profile is proposed and investigated in this letter. The band structures are calculated by using the finite element method. It is found that a complete bandgap at a significantly low frequency can be induced. The mechanism for such a change is suggested by using an equivalent spring-mass model based on analyzing the eigen modes at the bandgap edges. Consistent results are obtained from the numerical results and the analysis of the spring-mass model.
Bandgaps and directional propagation of elastic waves in two-dimensional square zigzag lattice structures
Yan-Feng Wang,Yue-Sheng Wang,Chuanzeng Zhang
Physics , 2014, DOI: 10.1088/0022-3727/47/48/485102
Abstract: In this paper we propose some kinds of two-dimensional square zigzag lattice structures and study their bandgaps and directional propagation of elastic waves. The band structures and the transmission spectra of the systems are calculated by using the finite element method. The effects of the geometry parameters of the 2d-zigzag lattices on the bandgaps are investigated and discussed. The mechanism of the bandgap generation is analyzed by studying the vibration modes at the bandgap edges. Multiple wide complete bandgaps are found in a wide porosity range owing to the separation of the degeneracy by introducing bending arms. The bandgaps are sensitive to the geometry parameters of the systems. The deformed displacement fields of the transient response of finite structures subjected to harmonic loads are presented to show the directional wave propagation. The research work in this paper is relevant to the practical design of cellular structures with enhanced vibro-acoustics performance.
Thermodynamic, Electromagnetic, and Lattice Properties of Antiperovskite Mn3SbN
Ying Sun,Yan-Feng Guo,Yoshihiro Tsujimoto,Xia Wang
Advances in Condensed Matter Physics , 2013, DOI: 10.1155/2013/286325
Fabrication and Characterization of Manganese Ferrite Nanospheres as a Magnetic Adsorbent of Chromium
Li-Xia Yang,Feng Wang,Yan-Feng Meng,Qing-Hua Tang
Journal of Nanomaterials , 2013, DOI: 10.1155/2013/293464
Medical Object Extraction by Gaussian Mixture Model and Region Competition Active Contour Model

SHANG Yan-feng,WANG Hui,WANG Ning,

计算机科学 , 2012,
Abstract: This paper proposed a regional active contour model with an embedded classifier, based on a Gaussian mixlure model fitted to the intensity distribution of the medical image. The difference between the maximum probability of the intensities belonging to the classes or subclasses of the object and those of the background is made as an energy term in the active contour modcl,and minimization of the whole energy function leads to a novel iterative equation. An additional speed controlling term slows down the evolution of the active contour when it approaches an edge, making it quickly convergent to the ideal object. The developed model has been applied to liver segmentation. Some comparisons are made between the geodesic active contour,C-V(active contour without edges),manual outline and our model. As the experiments show that our model is accurate,flexible and suited to extract objects surrounded by a complicated back-ground.
Medical object extraction model based on regional energyminimization and active contour model

SHANG Yan-feng,WANG Ning,WANG Hui,
,汪 宁,汪 辉

计算机应用研究 , 2012,
Abstract: In order to solve the problems of traditional active contour models, which move in a high speed on strong edge or leak out on weak edge, this paper proposed a medical object extraction model which was based on regional energy minimization and active contour model. The model employed objects' statistical intensity distribution in a level set framework, and expressed energy function as an integral of probability of pixels belonging to objects. The energy function was minimized in a level set framework which led to a iterating equation. At the same time, an edge based speed constrain term was able to slow down the active contours when they steped over a steep boundary of the objects, which made the extraction procedure more convergent and accurately. As shown in the experiments of coronary and mitral valve extraction with comparison with several classical models and manual outline, the proposed model is able to extraction medical objects in an automatic way and the results are also more robust, accurate, and convergent than several traditional models.
Reducing symmetry in topology optimization of two-dimensional porous phononic crystals
Hao-Wen Dong,Yue-Sheng Wang,Yan-Feng Wang,Chuanzeng Zhang
Physics , 2015, DOI: 10.1063/1.4936640
Abstract: In this paper we present a comprehensive study on the multi-objective optimization of two-dimensional porous phononic crystals (PnCs) in both square and triangular lattices with the reduced topology symmetry of the unit-cell. The fast non-dominated sorting-based genetic algorithm II is used to perform the optimization, and the Pareto-optimal solutions are obtained. The results demonstrate that the symmetry reduction significantly influences the optimized structures. The physical mechanism of the optimized structures is analyzed. Topology optimization combined with the symmetry reduction can discover new structures and offer new degrees of freedom to design PnC-based devices. Especially, the rotationally symmetrical structures presented here can be utilized to explore and design new chiral metamaterials.
STUDIES ON THE MACRORETICULAR CHELATE RESINS --Study on the Structure for Macroreticular PSA Resins of Acrylonitrile System and Their Preparation

LI Yan-feng,WANG Huai-kui,

高分子学报 , 1990,
Abstract: The macroreticular acrylonitrile-styrene-divinylbenzene copolymers (MR-PSA resins) have-been synthesized successfully by the suspension polymerization,using the linear polystyrene (PS):linear pre-polystyrene (PPS) and mixture of PPS-cyclohexane as pore-creating agents.The morphological structure and porous structure of the MR-PSA resins have been studied by using scanning electron microscopy (SEM),BET method and density-bottle method.From the micrography and porous-parameters of the MR-PSA resins.we found:When the crosslink-ing degree is same,the morphol9gical structure of the MR-PSA resins change from“gel—flake”into“gel-granule” with the increasing of the content of polymeric pore—creating agents ap-plied,and their porous structures are improved in the meantime.The morphological structure and porous structure of the MR—PSA resins are also dependent on the sort of polymeric pore—creating system,PPS—cyclohexane is the best in the three sorts of polymeric pore-creating sys-tem used.The copolymeric compositions and other properties of the MR—PSA resins have been studied by the FT-IR,TG-DTG and Kjeldahod’s method.
Expression of COX-2 and Bcl-2 in primary fallopian tube carcinoma: correlations with clinicopathologic features
Fang Wang,Guo-Ping Sun,Yan-Feng Zou,Qiang Wu
Folia Histochemica et Cytobiologica , 2011, DOI: 10.5603/9432
Abstract: The aim of this study was to evaluate the expression of COX-2 and Bcl-2 in primary fallopian tube carcinoma (PFTC), as well as their correlations with clinicopathologic features. We studied a cohort of 33 patients with a pathological diagnosis of PFTC. Thirty normal tubal tissues used for controls were obtained from patients diagnosed with uterine myomas. Expression analysis for COX-2 and Bcl-2 was performed using the immunohistochemical technique. The rate of preoperative diagnosis was 18.2%. With a median survival of 61.0 months (95% CI: 43.2 to 78.8 months), the estimated five-year overall survival rate in the 33 patients was 39.0%. Increased expression of COX-2 and Bcl-2 was observed in tumor specimens compared to normal controls (p = 0.026; p = 0.003). The expression rate of COX-2 in node-positive tumors was significantly higher than that of node-negative tumors (p = 0.024). Moreover, the expression rate of COX-2 was statistically significantly higher in patients with infiltration through the serosa (p = 0.019). Positive significant associations were observed between Bcl-2 staining index and FIGO stage (p = 0.015), and between Bcl-2 staining and lymph node metastasis (p = 0.010). There was a significant correlation between COX-2 expression and Bcl-2 staining index (r = 0.517, p = 0.002). We conclude that COX-2 and Bcl-2 may potentially be useful prognostic markers for PFTC. The exact molecular mechanism for correlations between COX-2 and Bcl-2 remains to be elucidated. (Folia Histochemica et Cytobiologica 2011, Vol. 49, No. 3, 389–397)
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