基于CAE的薄壁壳体注塑分析

通过华塑CAE模流分析，在产品设计过程中预测可能出现的缺陷，对薄壁塑料壳体进行注塑分析，优化了薄壁壳体的结构强度，提高了塑件设计的质量和效率。     

Morphology,mechanical, and rheological behavior of microcellular injection molded EVA–clay nanocomposites

Ethylene vinyl acetate (EVA)/montmorillonite (MMT) nanocomposites diluted from master batch (50 wt.%) with EVA and EVAgMA was used in this study. The organoclay EVA nanocomposites were then injection molded by conventional and microcellular methods. Nitrogen was used as the blowing agent. The effect of organoclay content and MA grafted EVA on the morphology and the mechanical and rheological properties of the EVA–clay nanocomposites were then investigated. The results showed that the mechanical properties (tensile and impact) increased as the clay content increased. Cell size decreased as the clay loading increased. The EVAgMA nanocomposites had better mechanical properties than the EVA nanocomposites. XRD results showed that the EVAgMA nanocomposites have an exfoliated layered structure while the EVA nanocomposites are intercalated. Rheological results showed the viscosity is clay loading dependent and that the shear thinning effect occurs at high shear rates.     

Structural,electronic, and magnetic properties of zigzag-edged BN nanoribbons with 558-type line defects

The 558-type line defect is introduced into zigzag-edged BN nanoribbons (ZBNNRs), similar to that be found in graphene, and the structural, electronic, and magnetic properties for such defective ZBNNRs are investigated systematically. It shows that they are highly stable. In the nonmagnetic state, the metallic property of ZBNNRs remains unchanged regardless of the defect positions, but different defect positions give rise to different influences on the total DOS and PDOS at the Fermi level. Interestingly, in the magnetic state, the thermal stability of magnetism is enhanced greatly when the line defect appears at most positions, even comparable with room temperature. When the line defect position shifts from the B-edge to the N-edge, the transition from the half-metal to the magnetic semiconductor or spin unpolarized semiconductor is induced. And also, the response of defect ribbons to an in-plane transverse electric field is essentially different from defect-free ribbons, and the half-metallic feature can be enhanced by an electric field for the line defect introduced into certain positions in a ribbon.     

Detection of Damaged Distribution Surge Arresters Using an Impulse Generator

Distribution surge arresters with an internal series gap have been installed on Japanese distribution lines at high density to reduce lightning‐related overvoltages. In contrast, surge arresters are sometimes damaged by direct lightning strokes, particularly in winter. Measurement of the insulation resistance between the terminals of the surge arrester and measurement of the dc discharge voltage of the surge arrester are generally adopted to detect damaged arresters. However, if metal‐oxide (MO) varistors are damaged and the internal series gap is not damaged, it is difficult to detect damaged arresters by the two conventional methods. Therefore, this paper presents a proposed detection method that can accurately detect damaged arresters. In the proposed method, first, the voltage between the terminals of the surge arrester is measured when the output of an impulse generator is applied to the surge arrester. Second, the damaged arrester is detected by comparison between its voltage waveform and the voltage waveform of the nondamaged arrester. The detection rate of damaged arresters by the proposed method is markedly higher than the rates of detection by the two conventional methods.     

再析纺纱时钢丝圈在钢领上位置倾侧

进一步叙述在离心力分量FMy不略去时钢丝圈平面空间位置,它在坐标平面x'Ay'上迹线u的倾角κ0,并且∠κ=∠δ;经实例计算,钢丝圈平面的位置角δ较小。但已说明了纺纱时钢丝圈外脚超前。钢丝圈平面在坐标平面y'Az'上迹线w的倾角χ表明它呈整体前倾,导致钢丝圈纱线通道高度减小。分析钢丝圈上纱作用点J的坐标比q/s得出,质心高度低、圈形小的钢丝圈前倾大,纱线通道小。至于钢丝圈外倾角τ,它是钢丝圈几何图形在坐标平面x'Az'上投影对于轴Az'形成的,可直接从动态图上测量得。指出:纺纱时钢丝圈外倾是不可避免的,其质心坐标c应由气圈纱张力及形状确定之;按τ和c/a算出的τ0v将是角τ0的最小值;角τ0可从钢丝圈和钢领呈弧面接触,钢丝圈下腿圆弧半径须为r1的条件确定;掌握"圈径"概念对钢丝圈和钢领设计和使用非常有利,应注意圈径长度A0M0≌AMv,每只钢丝圈都有属于自己的圈径A0M0,其斜度和长度已被确定而成为技术特征数。     

2020加强型数控角钢线的技术水平及特点分析

本文通过对2020加强型数控角钢线的技术水平及特点分析,介绍了锻压产品中该系列产品发展趋势,同时对其取代国外同类产品,创造社会效益和经济效益的期待。     

(F,K, b)-vex sets and some related properties

In this paper, we introduce the concept of (F, K, b)-vex sets in vector spaces which is a generalization of (E-b)-vex sets given by Mishra, Mohapatra and Youness. Some properties of (F, K, b)-vex sets are investigated.     

How to design effective priority rules: Example of simple assembly line balancing

Priority rule-based methods (PRBMs) rely on problem-specific knowledge to construct good solutions in a very short time. They can be used as stand-alone procedures or can be integrated into (partial) enumeration procedures, like branch and bound or dynamic programming, and heuristic solution methods. PRBMs are especially important for solving NP-hard optimization problems.In this paper, we formulate general design principles on how to construct good-performing PRBMs, based on a thorough computational investigation. Our principles allow to construct effective PRBMs already ad hoc, i.e. without time-consuming data mining algorithms. We conduct our analysis on the example of the NP-hard Simple Assembly Line Balancing Problem (SALBP), on which with small modifications most situations in the planning of assembly lines are based. We also provide a cross-validation of our results and illustrate the application of the formulated principles.     

1∶2000成图比例尺数字航空摄影测量质量控制与保障

通过《太原市1∶2 000成图比例尺数字航空摄影测量》项目实践,以该项目中1∶2 000数字线划图制作为例,结合数据分层详细介绍了数字摄影测量中的质量控制与保障的措施,以供类似测量工作借鉴。