斜齿轮参数化设计系统开发

采用UG自带的二次开发工具UG/Open,结合标准斜齿轮的设计流程,开发了一种基于程序的斜齿轮参数化设计系统。首先运用Visual C++中的MFC类库设计系统数据库的界面,使用COM组件完成访问和修改数据库中的设计参数,并通过UG/Open API将得到的参数回传给主程序,然后调用UG/Open Grip编写的斜齿轮参数化设计程序,最终实现了标准渐开线斜齿轮的精确建模;该系统实现了知识重用,提高了斜齿轮三维数字模型的造型精度和设计效率,创建的模型能够很好的满足后续的CAE分析的要求。     

Application of iron-based cathode catalysts in a microbial fuel cell

Catalysts for the oxygen reduction reaction (ORR) in a microbial fuel cell (MFC) were prepared by the impregnation on carbon black of Fe^II acetate (FeAc), Cl–Fe^III tetramethoxyphenyl porphyrin (ClFeTMPP), and Fe^II phthalocyanine (FePc). These materials were subsequently pyrolyzed at a high temperature. The ORR activity of all Fe-based catalysts was measured at pH 7 with a rotating disk electrode (RDE) and their performance for electricity production was then verified in a continuous flow MFC. Catalysts prepared with FeAc and pyrolyzed in NH₃ showed poor activity in RDE tests as well as a poor performance in a MFC. The ORR activity and fuel cell performance for catalysts prepared with ClFeTMPP and FePc and pyrolyzed in Ar were significantly higher and comparable for both precursors. The iron loading was optimized for FePc-based catalysts. With a constant catalyst load of 2 mg cm⁻² in a MFC, the highest power output (550–590 mW/m²) was observed when the Fe content was 0.5–0.8 wt%, corresponding to only 0.01–016 mg Fe/cm². A similar power output was observed using a Pt-based carbon cloth cathode containing 0.5 mg Pt/cm². Long-term stability of the Fe-based cathode (0.5 wt% Fe) was confirmed over 20 days of MFC testing.     

黏性流体环境中压电宏纤维致动柔性结构的流固耦合振动特性及试验

柔性结构与周围流体的耦合作用机制广泛应用于仿生机器人、水下航行器、精密仪器及生命医疗等领域。具有驱动变形大、防水性好且柔韧性好的压电宏纤维（Macro fiber composite,MFC）致动器是水下柔性结构变形控制的首选。建立MFC内部致动弯矩和水动力载荷共同作用下柔性结构的流固耦合动力学模型。对粘贴MFC致动器的柔性结构特征截面进行计算流体动力学（Computational fluid dynamics,CFD）分析,得到不同振动特征频率下柔性结构周围流场、压力分布及所受水动力载荷,分别拟合得到MFC致动柔性结构水动力函数的实部和虚部表达式。结果表明柔性结构水动力载荷的附加质量和阻尼效应都随着振动频率的增加而减小。在等振动特征频率下,MFC致动梁结构水动力函数的实部大于匀质等截面梁的实部;在高振动频率下其水动力函数虚部同样大于匀质等截面梁。试验测试了MFC致动柔性结构的水下振动特性,试验所得MFC激励下柔性结构末端稳定振动的幅频特性和相频特性与建立的耦合动力模型相吻合,证实了所建立MFC致动柔性结构的水动力函数及流固耦合振动模型的有效性。     

基于Pro/E二次开发的注射机双曲肘合模机构的参数化设计

利用机构学的方法对双曲肘合模机构进行了运动分析,并确立了合模行程、各肘杆尺寸及最大启模角等参数间的关联关系。通过使用Pro/E二次开发技术,讨论了应用Pro/toolkit进行菜单开发及零件参数化实现的方法;以MFC对话框设计技术和VC++建立了双曲肘合模机构参数驱动自动生成技术,开发出了与Pro/E 4.0系统集成的合模机构零件参数化设计系统。     

Microbial fuel cell (MFC) using commercially available unglazed ceramic wares: Low-cost ceramic separators suitable for scale-up

This study aimed to evaluate the influence of commercially available unglazed wall ceramic (UGWC) and unglazed floor ceramic (UGFC) separators with different thickness and porosity on the performance of dual-chamber microbial fuel cells (MFCs). These MFCs were operated under continuous condition using domestic wastewater. The UGWC-based MFC produced higher maximum power density (321 mW/m² with a thickness of 9 mm) than UGFC-based MFC (106.89 mW/m² with a thickness of 3 mm) due to lower internal resistance. Power generation using both types of separators was lower than that of obtained using the Nafion 117 membrane as control (602 mW/m²). The maximum average coulombic efficiencies (CE) of the UGWC-based MFCs (with thickness levels of 6 and 9 mm) were 58% and 68%, respectively, which was more than that of UGFC-based MFCs and also control MFC (53%). Voltammetric analysis revealed that the maximum peak current of 6 mA was obtained for UGWC-based MFC which was in the order of control MFC (5.9 mA). The UGWC separators exhibited smaller ohmic and diffusion resistances of 57, 65 and 87 Ω in MFCs at the thickness levels of 3, 6 and 9 mm, respectively, compared to the UGFC separators with that of 164.27 and 366.23 Ω in MFCs at the thickness levels of 3 and 6 mm, respectively. UGWC separators because of their low production cost, high mechanical strength and increased output power density of the MFC proved to be a suitable alternative to replace with a costly polymeric membrane such as Nafion 117.     

Electricity and catholyte production from ceramic MFCs treating urine

The use of ceramics as low cost membrane materials for Microbial Fuel Cells (MFCs) has gained increasing interest, due to improved performance levels in terms of power and catholyte production. The catholyte production in ceramic MFCs can be attributed to a combination of water or hydrogen peroxide formation from the oxygen reduction reaction in the cathode, water diffusion and electroosmotic drag through the ion exchange membrane. This study aims to evaluate, for the first time, the effect of ceramic wall/membrane thickness, in terms of power, as well as catholyte production from MFCs using urine as a feedstock. Cylindrical MFCs were assembled with fine fire clay of different thicknesses (2.5, 5 and 10 mm) as structural and membrane materials. The power generated increased when the membrane thickness decreased, reaching 2.1 ± 0.19 mW per single MFC (2.5 mm), which was 50% higher than that from the MFCs with the thickest membrane (10 mm). The amount of catholyte collected also decreased with the wall thickness, whereas the pH increased. Evidence shows that the catholyte composition varies with the wall thickness of the ceramic membrane. The possibility of producing different quality of catholyte from urine opens a new field of study in water reuse and resource recovery for practical implementation.     

基于COM技术和WinSock技术的雷达显示系统设计

DCOM解决了COM在网络环境下的网络通信问题,方便了远程组件的创建和调用。文章提供了另一种实现远程组件功能的方法,不使用DCOM仅使用COM的一般技术,将Windows Sockets网络通信技术融入本地COM组件中,使其具有网络通信功能。结合OpenGL仿真雷达显示器画面,初步设计出有网络通信功能的雷达显示系统。     

基于MFC的多媒体播放器的实现

在VC+ +6.0平台上利用Windows Media Player控件实现了在程序中播放一段视频和音频的功能.测试结果证明该方法简单易行,极大缩短了程序的开发时间.     

Synergistic interaction of biocatalyst with bio-anode as a function of electrode materials

Comprehensive study was performed to understand the synergistic interaction between the biocatalyst and anode in terms of electron discharge (ED) pattern and microbial growth by varying electrode (bio-anode) materials viz., graphite, aluminum, brass, copper, nickel and stainless steel. Experiments were performed in bio-electrochemical cell consisting of three electrodes (bio-anode as working electrode, carbon rod as counter electrode and Ag/AgCl(S) as reference electrode) employing anaerobic mixed culture as anodic biocatalyst. Voltammetric and chronoamperometric analysis were used to enumerate the ED and redox reactions. Presence of higher microbial population and dominance of Gram positive bacteria with higher ED supported graphite function as a good bio-anode material. Nickel and stainless steel showed higher ED after graphite associated with dominance of Gram positive bacterial population. Although higher ED was noticed with brass, metal oxidation and decrement in ED with time doesn’t support its function as bio-anode. In spite of higher ED than nickel and stainless steel, aluminum and copper showed significant metal oxidation leading to change in both physical and electrochemical properties along with dominant growth of Gram negative bacteria. This study gives a comprehensive idea on biocatalyst interaction with anode in extracellular electron transfer which is important in improving the anode performance. Juxtaposing the results, it can be deduced that the outcome of the present study can be extended to all bio-electrochemical systems including microbial fuel cell (MFC).     

Geometrically Non-Linear Bending Analysis of Piezoelectric Fiber-Reinforced Composite (MFC/AFC) Cross-Ply Plate Under Hygrothermal Environment

A finite element formulation for geometrically non-linear bending behavior of smart structures integrated with piezoelectric fiber-reinforced composite (AFC/MFC) layer acting as distributed actuator is presented in this article. The formulation of this hygro-thermo-electro-mechanical coupled problem is based on the first-order shear deformation theory (FSDT) and the von Kármán type geometric non-linearity. Resulting non-linear algebraic governing equations are linearized by Newton–Raphson iterative method. A developed finite element formulation is initially solved for validation and comparison with existing results. A wide variety of numerical examples considering cross-ply laminated substrates subjected to combined mechanical, hygrothermal and electrical loads are presented. The effect of piezoelectric fiber orientation in an actuator to counteract non-linear deflections is analyzed.