摘要：硬质金属电极与柔软人体皮肤之间的界面失效会导致脑机接口器件的信号漂移和性能不稳定,影响脑电信号的精确采集.本研究设计并制备了一种聚多巴胺甲基丙烯酰胺-聚丙烯酰胺(PDMA-PAAM)水凝胶.将多巴胺引入到聚丙烯酰胺水凝胶中,通过多巴胺的氨基与邻苯二酚基团在有机-无机界面上建立共价和非共价相互作用提高了界面粘结力.金属电极与人体皮肤之间形成了强附着和有效模量过渡体系,PDMA-PAAM水凝胶与猪皮之间的剥离力达到22 N m^(-1).此外,通过添加氯化钠和甘油,PDMA-PAAM水凝胶具有稳定的电导率和室温下60天以上的长期使用寿命.将本研究制备的PDMA-PAAM水凝胶集成在柔性金电极上用于脑机接口,采集到的脑电信号强度和波形与同类商用产品基本一致,且PDMA-PAAM水凝胶柔性电极具有更稳定的界面.

摘要：Thermal performance was the most important factor in the development of borehole heat exchanger utilizing geothermal *** thermal performance was affected by many different design parameters,such as configuration type and borehole size of geothermal heat *** eventually determined the operation and cost efficiency of the geothermal heat exchanger *** main purpose of this work was to assess the thermal performance of geothermal heat exchanger with variation of borehole sizes and numbers of U-tubes inside a *** this,a thermal response test rig was established with line-source *** thermal response test was performed with in-line variable input heat *** thermal conductivity and thermal resistance were obtained from the measured *** the measurement,the effective thermal conductivity is found to have similar values for twopair type(4 U-tubes)and three-pair type(6 U-tubes)borehole heat exchanger systems indicating similar heat transfer ***,the thermal resistance shows lower value for the three-pair type compared to the two-pair *** data based resistance have lower value compared to computed result from design *** comparison finds better thermal performance for the three-pair type,however,fluctuating temperature variation indicates complex flow behavior inside the borehole and requires further study on flow characteristics.

摘要：This work presents an integrated pressure-tracking controller for a novel electro-hydraulic brake(EHB) system considering friction and hydraulic disturbances. To this end, a mathematical model of an EHB system, consisting of actuator and hydraulic sub-systems, is derived for describing the fundamental dynamics of the system and designing the controller. Due to sensor inaccuracy and measurement noise, a Kalman filter is constructed to estimate push rod stroke for generating desired master cylinder pressure. To improve pressure-tracking accuracy, a linear friction model is generated by linearizing the nonlinear Tustin friction model, and the unmodeled friction disturbances are assumed unknown but bounded. A sliding mode controller is designed for compensating friction disturbances, and the stability of the controller is investigated using the Lyapunov method. The performance of the proposed integrated controller is evaluated with a hardware-in-the-loop(HIL) test platform equipped with the EHB prototype. The test results demonstrate that the EHB system with the proposed integrated controller not only achieves good pressure-tracking performance, but also maintains robustness to friction disturbances.

摘要：在奥氏体不锈钢与铜合金异种材料摩擦焊接过程中,采用响应面方法优化摩擦焊接工艺参数,以获得抗拉强度最大和界面硬度最小的焊接接头。采用三因素、五水平中心复合正交矩阵来确定实验条件。得到20个焊接接头,测定了焊接接头的抗拉强度和界面硬度。采用方差分析(ANOVA)方法来确定起显著作用的、主要的及相互作用的参数,使用回归分析得到经验关系模型。用设计专家软件构造响应图和等高线图来优化摩擦焊接工艺参数。用得到的经验关系模型可以有效地预测焊接接头的抗拉强度和界面硬度,其置信水平达95%。从形成的等高线图可以得到所需的摩擦焊接的最佳条件。

摘要：通过建立一经验公式来预测熔化极气体保护焊十字接头根部失效的疲劳寿命。采用高强可时效硬化的AA7075-T6铝合金作为基材进行焊接实验。实验设计概念被用来优化进行疲劳实验所需要的次数。在一伺服液压控制疲劳实验机上进行疲劳实验,实验采用恒定荷载。采用所建立的经验公式,预测的熔化极气体保护焊十字接头根部失效疲劳寿命可达到95%的可信度水平。详细讨论了十字接头尺寸对疲劳寿命的影响。

摘要：The rapid development of information and communication technologies(ICTs)and cyber-physical systems(CPSs)has paved the way for the increasing popularity of smart ***-awareness is an important facet of product *** artifacts,various bio-systems are naturally characterized by their extraordinary *** inspired design(BID)is one of the most commonly employed design ***,few studies have examined the BID of context-aware smart products to *** paper presents a structured design framework to support the BID of context-aware smart *** meaning of context-awareness is defined from the perspective of product *** framework is developed based on the theoretical foundations of the situated function-behavior-structure ontology.A structured design process is prescribed to leverage various biological inspirations in order to support different conceptual design activities,such as problem formulation,structure reformulation,behavior reformulation,and function *** existing design methods and emerging design tools are incorporated into the framework.A case study is presented to showcase how this framework can be followed to redesign a robot vacuum cleaner and make it more context-aware.

摘要：采用混合概念设计方法,对油棕复合材料汽车防撞箱进行了概念设计。结合创新问题解决(TRIZ)理论、形态图和仿生学,考虑材料特性、功能规格、力识别、根本原因分析、几何形状和设计选择标准等方面的首要要求。该策略是利用自然物来激发五种创新的ACB结构的概念设计,并运用层次分析法进行两两分析来选择最佳的ACB概念设计。复合ACB的新概念设计考虑到了天然纤维的特性,而不像传统材料如钢合金和铝合金。排名最高(26.6%)的设计被选为最终的概念设计,该设计的最外层具有蜂窝结构,内部结构由蜘蛛网结构强化,中心部位是由啄木鸟海绵组织中提取的纤维泡沫结构支撑,以达到能量吸收能力最大化。新的设计可以解决ACB在碰撞过程中无法吸收最大冲击能量的主要原因-弯曲塌陷的问题。但是,为了生产和装配需要,最后的概念设计仍需修改,这些修改将在今后研究中完成。

摘要：In the present study to produce a typical hip joint, Investment casting has been selected as casting method since this process can give optimum properties of the product having complex geometry with biocompatible material. In order to perform this casting, a die or mould is needed to fabricate wax pattern, which will be used to make ceramic investment for the hip joint. Thus, this study includes the modification of design together with fabrication of a typical hip joint casting dies with acrylic. Throughout the project, modulus of casting and riser has been calculated and accommodated with the main hip joint die design. The hip-bone joint design has been generated using CATIA V5 software before it is converted into numerical control (NC) codes to machine the two acrylic slabs of the acrylic dies using Vertical Machining Center (VMC). Thus, the acrylic dies for hip bone joint are now ready for making wax pattern intended to produce ceramic investment for casting the required joint with biocompatible material.

摘要：The application of work strategies taking into account, from the initial stages, all the factors involved in the product design process is considered essential by the researches to generate higher quality products, assess users’ needs and anticipate design problems. This paper presents two approaches of design project development, denominated respectively: projects with imposed specifications and projects with derived specifications and proposes the use of the matrix that integrates specifications and design factors (SFM). This design support tool complements others already used in the development of product concepts by higher education students, increasing the capacity of synthesis and structuring of information in order to facilitate decision-making into the design process. Its elaboration implies understanding of objectives, identifying of factors and establishing of specifications. At the same time, it aims to foster the reflection process and an integrated information analysis. The application of SFM and its contribution to different project approaches are shown in this paper.

摘要：研究电弧收缩电流频率(ACCF)对收缩电弧钨极氩弧焊(CA-TIG)焊接航空航天718合金板(厚度为2 mm)拉伸性能和显微组织演变的影响。实验设计每次一个变量,即采用从4 kHz到20 kHz之间5个不同的ACCF,其他参数保持不变。结果显示,采用4 kHz ACCF的接头具有良好的拉伸性能,焊接效率可达99.20%。这是由于熔化区的晶粒细化导致枝晶间析出更细小、离散的Laves相。ACCF高于12 kHz时熔化区发生严重晶粒长大和粗大Laves相演变。718合金焊缝在较高的ACCF下由于冷却速度较慢,Nb偏析和Laves相形成的趋势更明显。当ACCF为20 kHz时,Laves相的体积分数比4 kHz时提高62.31%,因此,接头的拉伸性能降低。这主要是由于当ACCF增加时,焊接热循环中热输入的叠加。