Effect of shaft misalignment and friction force on time varying mesh stiffness of spur gear pair

Shaft misalignment and sliding friction between meshing teeth are considered as primary excitation to generate vibrations and extra dynamic loads on transmitting gear teeth. Time varying mesh stiffness (TVMS) is an important parameter to understand the dynamics of meshing gear pair. Potential energy method is one of the most acceptable methods to calculate TVMS. This paper proposes a computer simulation based approach to study the effect of shaft misalignment and friction on total effective mesh stiffness for spur gear pair. The results showed clearly that misalignment and friction affect TVMS of gear pair. The effect of misalignment and friction has also been studied for cracked gear pair and results are discussed.     

浅谈高强钢绞线——聚合物砂浆加固技术

高强钢绞线-聚合物砂浆加固技术是由韩国开发的一种较新的加固技术,与传统的加固技术相比有其显著的优越性.     

“填料+丝网”除雾技术在石化电厂氨法脱硫的工业应用

采用“填料+丝网”除雾的氨法脱硫工艺技术解决氨法脱硫“烟气拖尾”及气溶胶等问题，并在克拉玛依石化公司热电厂进行应用实践。实际的脱硫效率达到了98%以上，出口烟尘尘小于10mg/m3。     

齿轮裂纹对啮合刚度的影响分析

通过对三维轮齿接触有限元分析,建立了正常和齿根与分度圆处不同裂纹故障的直齿圆柱齿轮三维实体有限元模型;通过对其啮合接触分析,求得不同状态下齿轮整个啮合过程的轮齿啮合综合刚度.分析结果表明:齿根裂纹对啮合刚度的影响要大于分度圆裂纹的影响.这对分析裂纹故障对齿轮啮合刚度的影响具有一定的指导作用.     

WiMAX MMR网络的军事应用

为进一步提高战术通信网的性能,满足通信保障对网络传输带宽的需求,许多国家的军队使用了3G标准之一的WiMAX技术。WiMAX MMR网络基于IEEE802.16j标准,运用移动多跳接力技术,能有效解决现有WiMAX系统覆盖半径不足、信号传输不佳的问题。介绍WiMAX在军事通信领域的应用情况,结合IEEE802.16j MMR的特点,并就网络安全方面所面临的威胁提出了应对策略。分析表明:WiMAX MMR网络作为一种无线解决方案,具有良好的军事应用前景。     

A novel mesh subdivision algorithm for dense reconstruction from multi-image based on preliminary model

To solve the disadvantages of the recent three-dimensional (3D) reconstruction methods, this paper presents a dense reconstruction algorithm which incorporates image features into the mesh subdivision. A preliminary model is deformed from statistical deformation model (SDM) to catch the roughest features, and later densified under a multi-resolution frame to achieve a dense model until all image features are used. In every round of this framework, the image features are detected, and then cut into planar points. At the same time, the transitional model is re-projected into views, and all images are segmented to triangles. So the planar points are constrained by these triangles, and the corresponding relations among these triangles are certain. Then some new spatial points are generated from these planar points and subdivide the transitional model. Later, the transitional model is re-arranged to get a right topology, and becomes denser. This method contributes three novelties: (1) there is an inherited relationship between the later points and the early points; (2) if the hierarchy of multi-resolution frame and the number of new spatial points at every round are set appropriately, the transitional model evolves with a correct topology; (3) the density of the final model is proportional to the information account of views. The experiment validates these virtues.     

Simultaneous untangling and smoothing of quadrilateral and hexahedral meshes using an object-oriented framework

In this work, we present a simultaneous untangling and smoothing technique for quadrilateral and hexahedral meshes. The algorithm iteratively improves a quadrilateral or hexahedral mesh by minimizing an objective function defined in terms of a regularized algebraic distortion measure of the elements. We propose several techniques to improve the robustness and the computational efficiency of the optimization algorithm. In addition, we have adopted an object-oriented paradigm to create a common framework to smooth meshes composed by any type of elements, and using different minimization techniques. Finally, we present several examples to show that the proposed technique obtains valid meshes composed by high-quality quadrilaterals and hexahedra, even when the initial meshes contain a large number of tangled elements.     

Direct repair of self-intersecting meshes

A fast and exact algorithm to eliminate intersections from arbitrary triangle meshes is presented, without any strict requirement on the input. Differently from most recent approaches, our method does not rely on any intermediate representation of the solid. Conversely, we directly cut and stitch mesh parts along the intersections, which allows to easily inherit possible surface attributes such as colors and textures. We rely on standard floating point arithmetics whenever possible, while switching to exact arithmetics only when the available fixed precision is insufficient to guarantee the topological correctness of the result. Our experiments show that the number of these switches is extremely low in practice, and this makes our algorithm outperform all the state-of-the-art methods that provide a guarantee of success. We show how our method can be exploited to quickly extract the so-called outer hull even if the resulting model is non manifold by design and the single parts have boundaries, as long as the outer hull itself is unambiguously definable.     

工业无线技术在大型石油化工罐区自动化的应用

随着无线技术的迅速发展，在工业自动化领域的应用越来越广泛。本文介绍工业无线技术标准ISA100．11a及无线解决方案，霍尼韦尔基于ISA100．11a工业无线标准的解决方案在大型石油化工罐区自动化的应用。     

Matrix-based pairwise key establishment for wireless mesh networks

Wireless communication in wireless mesh networks (WMNs), like other types of wireless networks, is vulnerable to many malicious activities such as eavesdropping. As one of the fundamental security technologies, pairwise key establishment has been widely studied to secure wireless communication. In this paper, we propose a new matrix-based pairwise key establishment scheme for mesh clients in WMNs. A fact in WMNs is that mesh routers are more powerful than mesh clients, in both communication and storage. Motivated by this fact, expensive operations can be delegated to mesh routers to alleviate the overhead of mesh clients when establishing pairwise keys between them. Compared with other matrix-based schemes, our scheme has significant advantages: any two mesh clients can directly establish pairwise keys while communication and storage costs of mesh clients are significantly reduced.