全电动注塑机研究进展及在汽配电子行业中的应用

介绍了全电动注塑机的特色，综述了国内外全电动注塑机在精密注塑、智能注塑、高效注塑和绿色注塑方面的研究进展，并对全电动注塑机在汽配电子行业中的应用作了简单介绍。对双电机同步控制技术的逐渐成熟为全电动注塑机实现大型化提供了助力，全电动注塑机高效、精密、智能、节能、环保的优势在汽配电子行业显示了很好的应用前景。     

Prediction of process parameters of water-assisted injection molding based on inverse radial basis function neural network

Because of the introduction of new processing parameters in water-assisted injection molding (WAIM), processes control has become more difficult. First, design of experiment (DOE) was carried out by using optimized Latin hypercubes (Opt LHS). On the basis of this, computational fluid dynamics (CFD) method was used to simulate and calculate hollowed core ratios and wall thickness differences of cooling water pipe at different positions. Then inverse radial basis function (RBF) neural network model reflecting the fitting relationship between processing parameters and molding quality was established, and accuracy of the model was detected by cross validation. Finally, expected molding quality was applied to predict processing parameters, and the obtained molding quality under the predicted processing parameters was verified by computer aided engineering (CAE) simulation and experimental methods. The results showed that mean relative precisions of processing parameters such as melt temperature, delay time, short shot size, water pressure, and mold temperature for inverse RBF model were 98.6%, 93.6%, 98.5%, 93.9%, and 97.9%, respectively, which met the accuracy requirements. Furthermore, compared with expected values of hollowed core ratios and wall thickness differences, the average errors of CAE and experiment were 2.3% and 4.9%, respectively.     

车门内饰板优化分析及模具设计

利用CAE分析软件Moldex3D先找出整个设计是否存在缺陷,为了增加优化效率,采用田口实验设计法规划控制因子与配置。L9(34)直交表来求得成型条件的最佳化参数组别,观察结果并找出最佳成型条件,以降低成型后所发生的体积收缩率以及翘曲位移量。由S/N因子反应表可看出对于Z轴变形量在塑料温度209℃、保压时间11.025 s、冷却时间17.85 s时较优良。Z轴的翘曲从1.64 mm降低到1.04 mm,整体改善了36.5%,最终根据优化结果进行了模具设计。     

Liquid yield from juniper and mesquite bio‐fuel gasification

Mesquite (Prosopis glandulosa) and redberry juniper (Juniperus pinchotii) are two woody species which dominate uncultivated lands in the south central Great Plains, USA (Texas, Oklahoma) and may have potential for bioenergy utilization. In this study, these two biomasses were gasified in an adiabatic, updraft fixed‐bed gasifier using air as medium. The products include low heating value gas and liquid tar yield. The effects of fuel moisture content and the equivalence ratio (ER) on liquid yields including heavy tar and light tar and higher heating value (HHV) of the producer gas were investigated. It was found that updraft gasifiers produce a large amount of tar, in a range of 100 g/Nm³ of gas produced. As the equivalence ratio (ER) increased (i.e. more rich char conditions), peak temperature (T_peak) within the bed decreased due to the lesser partial oxidization. The liquid yield showed peak value with change in moisture content between 6 and 24%. Heavy tar is a very high quality fuel with a higher heating value of over 29 MJ/kg on a dry, ash‐free (DAF) basis which is a slightly higher than that of ethanol. Copyright © 2015 John Wiley & Sons, Ltd.     

激光熔注中增强相颗粒对晶粒生长影响的CA模拟

基于元胞自动机法,结合Moore型邻居定义和晶粒生长理论,建立了增强相颗粒SiC对镁合金激光熔注中表层316L不锈钢晶粒生长的影响模型,模型考虑了晶界迁移率和晶界能等因素,实现了不同增强相颗粒体积分数和颗粒尺寸对晶粒生长影响的计算机模拟。结果表明,所建立的模型能较好的模拟晶粒生长过程,所得晶粒生长指数为0.42;增强相颗粒体积分数含量越高,晶粒生长越慢,晶粒尺寸越小;增强相颗粒尺寸越小,晶粒生长的越慢,晶粒尺寸越小,组织越均匀。     

Performance investigation of multi-stage saturation cycle with natural working fluids and low GWP working fluids

Improving the efficiency of a vapor compression cycle and using low GWP working fluids have become more important than ever due to the environmental concerns. A saturation cycle consisting of saturation compression and saturation expansion was proposed in order to improve a vapor compression cycle performance by reducing thermodynamic losses associated with single phase gas compression and isenthalpic expansion. The saturation cycle can be approached by multi-stage cycles with two-phase refrigerant injection. In this paper, the performance of saturation cycle was theoretically investigated for low GWP working fluids including natural fluids under ASHRAE standard operating conditions and extreme heating condition. The simulation results indicate that the benefit of using the multi-stage cycle is higher for the cycle with higher pressure ratio. When the saturation cycle technique (four-stage cycle) is applied, the COP improvements of D2Y60 (mixture of R32 and R1234yf), CO₂ and propane are 46.9%, 43.2% and 38.2%, respectively under extreme heating condition.     

注采比对“二三结合”开发模式渗流特征的影响

大庆油田的开发逐渐进入高含水阶段,厚油层动用程度低,"二三结合"开发模式是有效的提高厚油层动用程度,改善水驱开发效果,提高油田采收率的有效手段。在"二三结合"开发模式注聚阶段中注采比对井间压力、含水饱和度等变化有重要影响。为了探究注采比对开发层位的井间压力及饱和度的影响,利用油藏数值模拟方法,模拟了相同的开发模式不同注采比的生产情况,绘制了不同注采比情况下,不同层位的井间压力及含水饱和度变化情况,为维持地层压力平衡,保持油田稳定生产提供有力的依据。     

Study of metal assisted anisotropic chemical etching of silicon for high aspect ratio in crystalline silicon solar cells

Textured surface is commonly used to enhance the efficiency of silicon solar cells by reducing the overall reflectance and improving the light scattering. In this study, a comparison between isotropic and anisotropic etching methods was investigated. The deep funnel shaped structures with high aspect ratio are proposed for better light trapping with low reflectance in crystalline silicon solar cells. The anisotropic metal assisted chemical etching (MACE) was used to form the funnel shaped structures with various aspect ratios. The funnel shaped structures showed an average reflectance of 14.75% while it was 15.77% for the pillar shaped structures. The average reflectance was further reduced to 9.49% using deep funnel shaped structures with an aspect ratio of 1:1.18. The deep funnel shaped structures with high aspect ratios can be employed for high performance of crystalline silicon solar cells.     

负泊松比针织结构及其应用

本文对各个负泊松比材料的作用原理进行概括和总结,并简要介绍了目前用针织技术实现负泊松比结构的方案,包括平面经编织物、三维间隔织物、纬编折叠结构织物等。最后对负泊松比结构针织物在服用和产业用方面广泛的潜在应用分别进行了介绍,并展望了负泊松比结构针织物在以后研究中的发展方向及前景。     

Difference angle quantization index modulation scheme for image watermarking

In this paper, we propose a new angle quantization index modulation (AQIM) method, called the difference AQIM (DAQIM) method. The proposed method aims to improve the watermarking performance against gain attacks. Unlike the original AQIM method (Ourique et al., Angle QIM: a novel watermark embedding scheme robust against amplitude scaling distortions, in: Proceedings of IEEE International Conference on Acoustics, Speech, and Signal Processing, vol. 2, 2005, pp. 797–800), the DAQIM method quantizes the difference of the two angles instead of the angles themselves. The main advantage of the DAQIM method is to disperse the interference to the watermark signal from one angle to more angles. Thus, the watermark has a higher ability to resist attacks. We perform a theoretical analysis of the document-to-watermark ratio (DWR) based on our proposed method. We show that our proposed method can obtain a lower embedding distortion compared to the AQIM and the gradient direction watermarking (GDWM) (Nezhadarya et al., IEEE Trans. Inf. Forensics Secur., 6(4), 2011, 1200–1213), methods under the same robustness and payload conditions. The experimental results demonstrate that our proposed method outperforms common existing methods in terms of the robustness against various attacks such as the JPEG quantization noise, additive white Gaussian noise (AWGN), cropping effect and mean filtering.