硬态车削H13钢切削力与表面粗糙度试验研究

为了探究H13钢硬态车削过程中的切削力与工件表面粗糙度,课题组采用单因素试验和多因素正交试验法设计车削试验。通过极差分析法对试验结果进行分析,研究不同切削速度、进给量和背吃刀量对切削过程中切削力以及工件表面粗糙度的影响,并比较切削力与表面粗糙度的变化规律。结果表明：影响切削力的显著性参数为背吃刀量＞进给量＞切削速度;影响工件表面粗糙度的显著性参数为进给量＞切削速度＞背吃刀量。通过单因素试验分析可知,切削力与表面粗糙度变化有一定的相关性,表面粗糙度的变化趋势和切削力一致。     

Unionization Structures in International Oligopoly

We examine how competition in international markets affects a union's choice of wage regime, which can be either uniform or discriminatory. Firms are heterogeneous with regard to international competition. When unions choose their wage regimes sequentially, a discriminatory outcome becomes more likely when international competition increases. However, for intermediate levels a union may stick with a uniform wage regime even if the rival union adopts a discriminatory regime. When competition is sufficiently intense, both unions revert to the discriminatory regime. Paradoxically only in those latter instances all parties (consumers, workers, and firms) may be better off (each in aggregate) if all unions adopt a uniform wage regime. We conclude that union incentives to coordinate their wage regimes should then also become largest.     

The Motherhood Wage Penalty and Its Determinants: A Public–Private Comparison

We investigate whether public and private sector employees bear a different wage penalty for having children. According to our estimates, the total motherhood wage penalty is much larger in the private than in the public sector. Nevertheless, in both sectors, we find no unexplained penalty once we control for potential determinants of the family pay gap, namely, a reduced labour supply of mothers, child‐related career interruptions, less access to management positions, and adjustments in working conditions. Finally, only child‐related career interruptions play a different role in explaining the motherhood wage penalty in each sector.