Polynomials of Degree-Based Indices for Three-Dimensional Mesh Network

In order to study the behavior and interconnection of network devices,graphs structures are used to formulate the properties in terms of mathematical models.Mesh network(meshnet)is a LAN topology in which devices are connected either directly or through some intermediate devices.These terminating and intermediate devices are considered as vertices of graph whereas wired or wireless connections among these devices are shown as edges of graph.Topological indices are used to reflect structural property of graphs in form of one real number.This structural invariant has revolutionized the field of chemistry to identify molecular descriptors of chemical compounds.These indices are extensively used for establishing relationships between the structure of nanotubes and their physico-chemical properties.In this paper a representation of sodium chloride(NaCl)is studied,because structure of NaCl is same as the Cartesian product of three paths of length exactly like a mesh network.In this way the general formula obtained in this paper can be used in chemistry as well as for any degree-based topological polynomials of three-dimensional mesh networks.

A BLOCK-CENTERED UPWIND APPROXIMATION OF THE SEMICONDUCTOR DEVICE PROBLEM ON A DYNAMICALLY CHANGING MESH

The numerical simulation of a three-dimensional semiconductor device is a fundamental problem in information science. The mathematical model is defined by an initialboundary nonlinear system of four partial differential equations: an elliptic equation for electric potential, two convection-diffusion equations for electron concentration and hole concentration, and a heat conduction equation for temperature. The first equation is solved by the conservative block-centered method. The concentrations and temperature are computed by the block-centered upwind difference method on a changing mesh, where the block-centered method and upwind approximation are used to discretize the diffusion and convection, respectively. The computations on a changing mesh show very well the local special properties nearby the P-N junction. The upwind scheme is applied to approximate the convection, and numerical dispersion and nonphysical oscillation are avoided. The block-centered difference computes concentrations, temperature, and their adjoint vector functions simultaneously.The local conservation of mass, an important rule in the numerical simulation of a semiconductor device, is preserved during the computations. An optimal order convergence is obtained. Numerical examples are provided to show efficiency and application.

Development and validation of a three-dimensional,wave-current coupled model on unstructured meshes

Using unstructured meshes provides great flexibility for modeling the flow in complex geomorphology of tidal creeks,barriers and islands,with refined grid resolution in regions of interest and not elsewhere.In this paper,an unstructured three-dimensional fully coupled wave-current model is developed.Firstly,a parallel,unstructured wave module is developed.Variations in wave properties are governed by a wave energy equation that includes wave-current interactions and dissipation representative of wave breaking.Then,the existing Finite-Volume Coastal Ocean Model(FVCOM) is modified to couple with the wave module.The couple procedure includes depth dependent wave radiation stress terms,Stokes drift,vertical transfer of wave-generated pressure transfer to the mean momentum equation,wave dissipation as a source term in the turbulence kinetic energy equation,and mean current advection and refraction of wave energy.Several applications are presented to evaluate the developed model.In particular the wind and wave-induced storm surge generated by Hurricane Katrina is investigated.The obtained results have been compared to the in situ measurements with respect to the wave heights and water level elevations revealing good accuracy of the model in reproduction of the investigated events.In a comparison to water level measurements at Dauphin Island,inclusion of the wave induced water level setup reduced the normalized root mean square error from 0.301 to 0.257 m and increased the correlation coefficient from 0.860 to 0.929.Several runs were carried out to analyze the effects of waves.The experiments show that among the processes that represent wave effects,radiation stress and wave-induced surface stress are more important than wave-induced bottom stress in affecting the water level.The Hurricane Katrina simulations showed the importance of the inclusion of the wave effects for the hindcast of the water levels during the storm surge.

Three-dimensional interconnected Ni（Fe）OxHy nanosheets on stainless steel mesh as a robust integrated oxygen evolution electrode

The development of an electrocatalyst based on abundant elements for the oxygen evolution reaction （OER） is important for water splitting associated with renewable energy sources. In this study, we develop an interconnected Ni（Fe）OxHy nanosheet array on a stainless steel mesh （SSNNi） as an integrated OER electrode, without using any polymer binder. Benefiting from the well- defined three-dimensional （3D） architecture with highly exposed surface area, intimate contact between the active species and conductive substrate improved electron and mass transport capacity, facilitated electrolyte penetration, and improved mechanical stability. The SSNNi electrode also has excellent OER performance, including low overpotential, a small Tafel slope, and long-term durability in the alkaline electrolyte, making it one of the most promising OER electrodes developed.

High Order Schemes on Three-Dimensional General Polyhedral Meshes—Application to the Level Set Method

In this article,we detail the methodology developed to construct arbitrarily high order schemes—linear and WENO—on 3D mixed-element unstructured meshes made up of general convex polyhedral elements.The approach is tailored specifically for the solution of scalar level set equations for application to incompressible two-phase flow problems.The construction of WENO schemes on 3D unstructured meshes is notoriously difficult,as it involves a much higher level of complexity than 2D approaches.This due to the multiplicity of geometrical considerations introduced by the extra dimension,especially on mixed-element meshes.Therefore,we have specifically developed a number of algorithms to handle mixed-element meshes composed of convex polyhedra with convex polygonal faces.The contribution of this work concerns several areas of interest:the formulation of an improved methodology in 3D,the minimisation of computational runtime in the implementation through the maximum use of pre-processing operations,the generation of novel methods to handle complex 3D mixed-element meshes and finally the application of the method to the transport of a scalar level set.

轻量型网片和重量型网片应用于Lichtenstein腹股沟疝修补术长期疗效的Meta分析

目的评价Lichtenstein腹股沟疝修补术中轻量型网片与重量型网片的远期临床疗效及安全性。方法计算机检索Pub Med、EMBASE、The Cochrane图书馆、Web of Science、中国生物医学文献数据库、中国期刊全文数据库、万方数字化期刊群和维普中文科技期刊数据库,检索时间均从建库至2013年11月,同时追溯纳入文献的参考文献。由两名评价者按照纳入与排除标准以及Cochrane协作网推荐的方法独立筛选文献、提取资料并评价纳入研究的方法学质量后,采用Rev Man 5.2.5软件进行Meta分析。结果共纳入15个随机对照试验,包含3 390例患者。Meta分析结果显示:与重量型网片相比,轻量型网片可减轻术后近期(≤12个月)慢性疼痛[6个月:相对危险度0.67,95%可信区间(0.53,0.83),P=0.000 3;12个月:相对危险度0.79,95%可信区间(0.64,0.98),P=0.03]和术后异物感[相对危险度0.69,95%可信区间(0.56,0.85),P=0.000 5];而在术后远期(>12个月)疼痛[相对危险度0.93,95%可信区间(0.72,1.19),P=0.56]、复发[相对危险度1.21,95%可信区间(0.77,1.90),P=0.41]和睾丸萎缩[相对危险度1.90,95%可信区间(0.58,6.28),P=0.29]的发生率方面差异无统计学意义。结论与重量型网片相比,轻量型网片可降低术后短期慢性疼痛并减少异物感,且未增加复发。在腹股沟疝修补术中,可以将轻量型网片作为首选。

轻量型平片与3D重量型补片在经腹腹膜前疝修补术中的效果比较

目的比较轻量型平片与3D重量型补片在经腹腹膜前疝修补术(TAPP)中的应用效果。方法回顾性分析60例因腹股沟疝行TAPP术的患者临床资料。根据术中使用补片情况分为轻量型平片组(A组)和3D重量型组(B组),各30例。对比两组术中补片安放时间、首次离床活动时间、术后并发症及术后6个月疝复发情况等,采用视觉模拟评分(VAS)比较两组术后1、3、6个月的疼痛情况。结果两组补片安放时间及首次离床活动时间比较,差异均无统计学意义(P>0.05);两组的VAS评分均有随时间变化的趋势(P<0.05),且在术后第1个月A组患者的VAS评分低于B组(P<0.05),但分组与时间无交互作用(P>0.05);术后随访6个月,两组患者均未出现相关并发症及疝复发的情况。结论在TAPP术中应用轻量型平片可早期减轻患者术后疼痛。

MODELING UNCONFINED SEEPAGE FLOW USING THREE-DIMENSIONAL NUMERICAL MANIFOLD METHOD

Three-dimensional numerical manifold method for unconfined seepage analysis is proposed in this article.By constructing hydraulic potential functions of the manifold element,the element conductivity matrix and the global simultaneous equations for unconfined seepage analysis are derived in detail.The algorithm of locating the free surface and the formula for seepage forces are also given.Three-dimensional manifold method employs the tetrahedral mathematical meshes to cover the whole material volume.In the iterative process for locating the free surface,the manifold method can achieve an accurate seepage analysis of the saturated domain below the free surface with mathematical meshes unchanged.Since the shape of manifold elements can be arbitrary,the disadvantage of changing the permeability of transitional elements cut by the free surface in the conventional Finite Element Method（FEM） is removed,and the accuracy of locating the free surface can be ensured.Furthermore,the seepage force acting on the transitional elements can be accurately calculated by the simplex integration.Numerical results for a typical example demonstrate the validity of the proposed method.

Overview of 3D Scene Viewpoints evaluation method

The research on 3D scene viewpoints has been a frontier problem in computer graphics and virtual reality technology.In a pioneering study,it had been extensively used in virtual scene understanding,image-based modeling,and visualization computing.With the development of computer graphics and the human-computer interaction,the viewpoint evaluation becomes more significant for the comprehensive understanding of complex scenes.The high-quality viewpoints could navigate observers to the region of interest,help subjects to seek the hidden relations of hierarchical structure,and improve the efficiency of virtual exploration.These studies later contributed to research such as robot vision,dynamic scene planning,virtual driving and artificial intelligence navigation.The introduction of visual perception had The introduction of visual perception had contributed to the inspiration of viewpoints research,and the combination with machine learning made significant progress in the viewpoints selection.The viewpoints research also has been significant in the optimization of global lighting,visualization calculation,3D supervising rendering,and reconstruction of a virtual scene.Additionally,it has a huge potential in novel fields such as 3D model retrieval,virtual tactile analysis,human visual perception research,salient point calculation,ray tracing optimization,molecular visualization,and intelligent scene computing.

Study on the computation method of temperature field of RCC dam

According to the construction characteristic of RCC dam cast by layers, three-dimensional finite element relocating mesh method is developed to simulate construction process and compute temperature field. The computation model of relocating mesh method is expatiated in detail; based on the thermodynamic properties of RCC materials, the feasibility and error of relocating mesh method are analyzed and demonstrated; The computation results in this article are verified by means of the temperature observation data of certain RCC gravity dam. The results show that the temperature field computed by three-dimensional finite element relocating mesh method can not only ensure the computation precision, but also improve the calculation efficiency greatly. This provides an effective method for simulating construction process and computing temperature field of RCC dam.

Discussion and study on contraction joints for RCC gravity dam

Based on the construction property of rolled compacted concrete, three-dimensional finite element relocating mesh method was developed in simulating construction process and computing temperature and stress field. Using this method, the temperature and the thermal stress fields developed in the RCC gravity dam of the Longtan project with or without a longitudinal joint during construction and operation are calculated so as to simulate the construction process. The computation results show that the value of the thermal stresses developed in the dam even, without any longitudinal joint, could meet the design criteria provided the placement temperature is adequately controlled.

A blind watermarking algorithm for 3D mesh models based on vertex curvature

We propose a robust blind watermarking algorithm for three-dimensional(3D)mesh models based on vertex curvature to maintain good robustness and improve visual masking in 3D mesh models.In the embedding process,by using the local window of vertex,the root mean square curvature is calculated for every vertex of the 3D mesh model and an ordered set of fluctuation values is obtained.According to the ordered fluctuation values,the vertices are separated into bins.In each bin the fluctuation values are normalized.Finally,the mean of the root mean square curvature fluctuation values of the vertices in each bin is modulated to embed watermark information.In watermark detection,the algorithm uses a blind watermark extraction technique to extract the watermark information.The experimental results show that the algorithm has a very good performance for visual masking of the embedded model and that it can resist a variety of common attacks such as vertex rearrangement,rotation,translating,uniform scaling,noise,smoothing,quantization,and simplification.

重量型补片与轻量型补片应用于腹股沟疝修补术的Meta分析

目的评价重量型补片与轻量型补片应用于腹股沟疝无张力修补对患者恢复的影响。方法检索PubMed、EMBase、Springer及Cochrane图书馆,结合查找到文献中的参考文献,检索时间从2000年1月至2010年9月,选择有关重量型补片与轻量型补片应用于腹股沟疝修补术的临床对照研究,由两位作者分别对研究质量进行评估,并提取有关资料,主要包括术后复发、血肿与血清肿、异物感,感染及疼痛的情况,采用RevMan5.0软件进行Meta分析。结果共纳入21项临床对照研究,其中16项为前赡性随机对照临床研究,包括5389例,其中重量型补片组2861例,轻量型补片组2528例。对纳入研究进行整体分析显示,轻量型补片组术后异物感发生率明显少于重量型补片组(p<0.05),优势比(Odds ratio)及95%可信区间为1.90(1.48,2.43),轻量型补片组术后慢性疼痛(12个月或更长)的发生率明显少于重量型补片组(p<0.05),OR及95%可信区间为1.39(1.10,1.75);两组患者在术后的复发、血肿(血清肿)、感染及早期疼痛的发生率无显著差异(p>0.05)。结论使用轻量型补片进行腹股沟疝无张力修补术,能减少术后的异物感及慢性疼痛,对术后的复发、血肿(血清肿)、感染及早期疼痛无明显影响。

A generic approach of integrating 3D models into virtual manufacturing

Various 3D modeling software has been developed for design and manufacturing. Most of the commercially available software uses native file formats, which may not be able to be read or understood by other software. This paper deals with the development of a generic approach of a 3D model conversion program for virtual manufacturing （VM）, using a lexical analyzer generator Lex and the Open Graphic Library （OpenGL）. The program is able to convert 3D mesh data between four universal file formats, i.e., Stereolithography （STL）, Virtual Reality Modeling Language （VRML）, eXtensible Markup Language （XML）, and Object （OBJ）. Simple assembly functions can be applied to the imported models. The quaternion angle is used for object rotation to overcome the problem of gimbal lock or a loss of one degree of rotational freedom. The program has been validated by importing the neutral format models into the program, applying the transformation, saving the new models with a new coordinate system, and lastly exporting into other commercial software. The results showed that the program is able to render and re-arrange accurately the geometry data from the different universal file formats and that it can be used in VM. Therefore, the output models from a VM system can be transferred or imported to another VM system in a universal file format.

轻型补片与传统补片在腹股沟疝修补术中有效性和安全性的荟萃分析

目的系统评价轻量型补片与传统补片在腹股沟疝修补术中的有效性和安全性。方法计算机检索Pub Med、Embase、Cochrane Library、中国生物医学文献数据库、中国科技期刊全文数据库、中国期刊全文数据库。全面收集比较轻量型补片与传统补片在腹股沟疝修有效性和安全性的随机对照试验(randomized controlled trials,RCTs),2名评价者独立评价纳入文献的方法学质量,用Rev Man 5.3软件进行统计分析。结果共纳入19篇RCTs,Meta分析结果显示,轻量型补片组与传统传统补片组患者在复发率方面比较,差异无统计学意义[RR=0.82,95%CI(0.56~1.19),P=0.30];在慢性疼痛[RR=0.68,95%CI(0.57~0.81),P<0.000 1]、异物感[RR=0.67,95%CI(0.56~0.81),P<0.000 1]及其并发症[RR=0.63,95%CI(0.51~0.77),P<0.000 1]方面比较,差异均有统计学意义。结论轻量型补片与传统传统补片在无张力疝修补术中的复发率方面相似,而轻量型补片减轻慢性疼痛、异物感及并发症发生方面优于传统补片。