Hierarchical Implicit Shape Modeling

In this paper, a new hierarchical approach for object detection is proposed. Object detection methods based on Implicit Shape Model (ISM) efficiently handle deformable objects, occlusions and clutters. The structure of each object in ISM is defined by a spring like graph. We introduce hierarchical ISM in which structure of each object is defined by a hierarchical star graph. Hierarchical ISM has two layers. In the first layer, a set of local ISMs are used to model object parts. In the second layer, structure of parts with respect to the object center is modeled by global ISM. In the proposed approach, the obtained parts for each object category have high discriminative ability. Therefore, our approach does not require a verification stage. We applied the proposed approach to some datasets and compared the performance of our algorithm to comparable methods. The results show that our method has a superior performance.     

Thermophoretic force measurements of aggregates of micro-spheres

Direct measurements of the thermophoretic force on spherical and non-spherical particles have been made using an electrodynamic balance mounted in a vacuum chamber. The non-spherical particles consisted of aggregates of polystyrene latex spheres. By varying the system pressure the force was measured over a wide range of Knudsen numbers ranging from the near-continuum regime to the free-molecule regime. The gases were monoatomic helium and diatomic nitrogen. The data were analyzed and normalized to determine the thermophoretic shape factor that relates the force on a non-spherical particle to that on a sphere of the same volume. The shape factors and the thermophoretic forces are compared with available theories. The measured thermophoretic forces are shown to agree with theories for the Knudsen regime and the free-molecule regime, and the thermophoretic shape factors are shown to be consistent with theories based on the limiting cases of large and small Knudsen numbers.     

带虚拟LED功能的多屏控制系统设计

本文设计了一种带虚拟LED功能的多屏控制系统。介绍了虚拟LED功能的实现原理和实现方法;阐述了系统启动和虚拟LED功能的实现流程。将虚拟LED功能集成到多屏控制系统中,可以解决指挥中心大屏幕和LED显示屏两套设备、两套软件的问题。带虚拟LED功能的多屏控制器使得大屏幕系统的安装更方便、操作更简便、稳定性更高。     

浅谈岩土预应力锚索孔道水泥灌浆的质量控制

岩土预应力锚固技术遍及土木工程的各个领域,如边坡、坝体、桥梁等。而岩土预应力锚索周围介质多为岩体和土体,环境条件比较复杂,高拉应力作用下的锚索腐蚀断裂,是威胁预锚使用寿命的主要因素。本文结合拉力型粘结式预应力锚索浅析岩土预锚从施工准备、成孔、锚索制作与安装、孔道灌浆的全过程对孔道水泥灌浆的影响因素和各环节质量控制,以确保孔道水泥灌浆的质量,为锚索提供可靠的锚固力和防腐蚀保障。     

Preliminary design and analysis of a cubic deployable support structure based on shape memory polymer composite

The deployable structures based on shape memory polymer composites (SMPCs) have been developed for its unique properties, such as high reliability, low-cost, lightweight, and self-deployment without complex mechanical devices compared with traditional deployable structures. In order to increase the inflatable structure system’s robustness and light the weight of it, a cubic deployable support structure based on SMPC is designed and analyzed preliminarily. The cubic deployable support structure based on SMPC consists of four dependent spatial cages, each spatial cage is composed of 12 three-longeron SMPC truss booms and end connections. The shape recovery of arc-shaped deployable laminates drive the three-longeron SMPC truss booms to unfold, thus realize the expansion of the deployable support structure. The concept and operation of the cubic deployable support structure are described in detail. A series of experiments are performed on the three-longeron deployable laminates unit and the simplified cubic deployable support structure to investigate the shape recovery behavior in the deployment process. Results indicate that the cubic deployable support structure has a high deployment-tgo-stowage volume ratio and can achieve self-deployment, package, and deploy without complex mechanical devices.     

基于形状特征的车削工时定额软件开发

结合我国中小型制造企业的特点,提出一种基于形状特征的车削工时定额方法。采用Visual Basic 6.0和Microsoft EXCEL电子表格,开发了新型工时定额系统。该系统根据毛坯尺寸与特征尺寸自动计算加工余量,自动确定切削参数,简化了操作过程,提高了工时的计算速率和准确性。该系统为产品成本的核算、生产计划的安排提供了数据支持。     

弹簧指数对镍钛合金弹簧缓冲吸能能力的影响

形状记忆合金(SMAs)弹簧具有大应变可逆变形能力,在吸能缓冲和振动控制等领域具有重要应用潜力。本工作研究了弹簧结构设计对镍钛SMAs性能的影响规律。采用冷拉拔和退火相结合的方法制备直径1.2mm的Ti-52.5at%Ni合金丝,并通过室温下芯轴绕制成型和高温退火相结合的方式制备弹簧指数C分别为6.0、7.7和9.3的弹簧,通过测试合金丝和弹簧的超弹性曲线研究弹簧结构的吸能性能。研究表明,基于弹簧的超弹性变形过程,室温(298K)下3类弹簧在120 mm的最大位移幅值下单位体积吸能分别为4618、2225和1143 kJ/m³,弹簧指数C为6.0的弹簧吸能能力最优。318K下,弹簧处于完全奥氏体态,弹簧指数C为6.0的弹簧单位体积吸能(6662kJ/m³)是同等载荷(47 N)条件下合金丝(34.7 kJ/m³)的192倍。同等条件下,弹簧结构具有比合金丝优异的吸能能力。因此,超弹性SMAs弹簧在缓冲减振结构上具有良好的应用前景。     

露天矿抛掷爆破工艺爆堆形态的数据融合估值算法

针对露天矿抛掷爆破工艺中的爆堆形态估算问题,提出了一种便捷的爆堆形态估值算法,仅利用采集到的同类多源数据即可得到精确的预测结果。提出了爆堆形态估值算法的计算步骤为“数据采样—融合精度判别—数据融合最优权值计算—获得数据融合结果”,并制定了数据采样规则、推导了精度判别方法与最优权值确定方法。以黑岱沟露天矿某次抛掷爆破工程为研究案例,分别利用爆堆形态数据融合估值算法与Weibull分布预测方法,在拉斗铲作业平盘高度为11~13m的情况下,对拉斗铲倒堆系统各工艺作业量进行了计算,结果显示：采用数据融合算法的误差可控制在5%以内,更优于Weibull分布预测方法,可以满足满足现场算量精度要求。     

Photo-mediated copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) “click” reactions for forming polymer networks as shape memory materials

The formation of polymer networks polymerized with the Copper (I) – catalyzed azide – alkyne cycloaddition (CuAAC) click reaction is described along with their accompanying utilization as shape memory polymers. Due to the click nature of the reaction and the synthetic accessibility of azide and alkyne functional-monomers, the polymer architecture was readily controlled through monomer design to manipulate crosslink density, ability for further functionalization, and the glass transition temperature (55–114 °C). Free strain recovery is used to quantify the shape memory properties of a model CuAAC network resulting in excellent shape fixity and recovery of 99%. The step growth nature of this polymerization results in homogenous network formation with narrow glass transitions ranges having half widths of the transition close to 15 °C for these materials resulting in shape recovery sharpness of 3.9%/°C in a model system comparable to similarly crosslinked chain growth polymers. Utilization of the CuAAC reaction to form shape memory materials opens a range of possibilities and behaviors that are not readily achieved in other shape memory materials such as (meth) acrylates, thiol-ene, thiol-Michael, and poly(caprolactone) based shape memory materials.     

Sensitivity Analysis Based Multiple Objective Preform Die Shape Optimal Design in Metal Forging

The multiple objective preform design optimization was put forward. The final forging＇s shape and deformation uniformity were considered in the multiple objective. The objective is to optimize the shape and the deformation uniformity of the final forging at the same time so that a more high integrate quality of the final forging can be obtained. The total objective was assembled by the shape and uniformity objective using the weight adding method. The preform die shape is presented by cubic B-spline curves. The control points of B-spline curves are used as the design variables. The forms of the total objective function, shape and uniformity sub-objective function are given. The sensitivities of the total objective function and the sub-objective functions with respect to the design variables are developed. Using this method, the preform die shape of an H-shaped forging process is optimally designed. The optimization results are very satisfactory.