钢铁产品点阵式打印机字符高度的控制方法

钢铁产品点阵式打印机是现代钢铁生产线上的重要辅助设备之一 ,其打印头有双列式 (两排交错布置 )和单列式两种 .前者的字符高度的控制方法类似针式打印机 ,而后者的控制原理则完全不同 .本文介绍了单列式打印头字符高度的控制原理 ,分析了不同情况下字符高度的限制条件 ,给出了相应的计算公式和实现方法 .     

基于大涡模拟方法的旋流过滤器内流场数值模拟

旋流过滤器在设计改进过程中,缺少对旋流过滤器和传统旋流器内流场的对比分析,且多孔介质阻力对流场影响的研究也较少,针对这一问题,文章选用大涡模拟( LES)方法对传统旋流器和不同多孔介质阻力下的旋流过滤器流场进行了数值模拟。得到了不同多孔介质阻力对旋流过滤器的轴向速度、切向速度、径向速度、静压、涡量及Q值的影响规律,并与传统旋流器内流场进行对比,获得了旋流过滤器流场内丰富的流动信息。结果表明与传统旋流器相比,旋流过滤器最大切向速度和压降减小;随多孔介质区域阻力的减小,最大切向速度和压降也随之减小。旋流过滤器减弱了旋流强度,增加了过滤能力,其内流场受多孔介质区域阻力影响较大。     

种粮大户经营风险感知机理与实证检验

基于安徽省21个产粮大县403个种粮大户的问卷调查,运用计划行为理论分析框架,构建序次Logit模型检验种粮大户的风险感知水平及其影响因素。在检验结果的基础上建立解释结构模型（ISM）,探究各因素对农户风险感知水平的影响机制。研究发现,技术培训频率、重大亏损经历和家庭务农人口对种粮大户风险感知水平产生显著正向影响,盈利动机强度、政策鼓励、家庭成员态度、农田基础设施完善程度、规模经营经验、市场风险应对能力、当期盈利对种粮大户风险感知水平产生显著负向影响。农田基础设施、过往亏损经历、当期盈利和技术培训频率是影响种粮大户风险感知水平的浅层因素,市场风险应对策略、盈利动机和规模经营年限是中层因素,而政策鼓励、家庭成员态度和家庭务农人口则是深层因素。     

当代诗歌的“钢铁诗学”--读龚学敏的《钢的城》

在这个钢筋铁骨的时代,龚学敏的第六本个人诗集《钢的城》其突出的特点在于对“钢铁”的诗性规划,并由此呈现了当代诗歌“钢铁诗学”,具有特别的意义。他从中国钢铁的源头展开的“钢铁之诗”,回到了“钢铁本身”,彰显出钢铁的柔性、温暖性、抒情性的一面。同时,在回到“钢铁本身”的“钢铁诗学”中,还张扬出一种浓烈的科技意识和理性精神,这为当代诗歌如何注入理性精神、科技意识的“新的抒情”走向,提供了一种新的诗学可能。     

1.2085葛利兹模具钢高速铣削参数的正交实验优选

针对饮料瓶吹塑模型腔在表面粗糙度方面的要求较高,精加工质量与多个因素相关的情况,提出采用正交实验 方法对加工过程中的切削速度、进给量、径向切削深度、轴向切削深度等要素进行评估,建立加工表面粗糙度与各工艺参 数之间的对应关系,从而确定影响加工质量的主要因素及其规律。研究结果表明,径向切削深度和轴向切削深度是影响 零件表面粗糙度的主要因素,而切削速度和进给量对表面质量的影响相对较小。实验结果有助于生产企业优化工艺参 数、提高生产效率。     

Convergence or Continuity? The Gender Gap in Household Labor After Retirement

This research examined 2 hypotheses about the effect of retirement on couples' division of household labor. The continuity hypothesis posits that the gender gap in household labor remains unaffected by retirement, whereas the convergence hypothesis expects it to close. The authors tested these hypotheses using longitudinal data from the German Socio‐Economic Panel Study (N = 1,302 couples). Fixed effects models revealed that male breadwinners doubled up on total hours of household labor across their transition to retirement. This rise was accompanied by a concurrent, albeit less pronounced, decline in wives' hours. As a result, the gender gap in household labor was cut in half. This convergence involved a moderate trade‐off in female‐typed tasks of routine housework and an increase in husbands' hours spent on male‐typed tasks of repairs and gardening. The study concludes that gendered patterns of time use change substantially after retirement, rendering couples' division of household labor more equitable in later life.     

Did the legalization of abortion increase women’s household bargaining power? Evidence from labor supply

I estimate the impact of abortion legalization on spouses’ labor supplies to test whether legalization increased women’s household bargaining power, in a collective household behavior framework. Based on CPS data, I find that wives’ labor supply decreased and their husbands’ increased, which is consistent with the bargaining hypothesis. This contrasts with most studies of abortion and birth control technologies, which predict a labor supply effect only for women, and of opposite sign. Also consistent with the bargaining interpretation, I estimate no significant impact on anti-abortion religious couples or on those who regularly used contraceptives. PSID data yield supportive evidence.

Testing for a unit root in an arima(p,1,0) signal observed with ma(q) noise

An ARIMA(p,1,0) signal disturbed by MA(q) noise is an ARIMA(p,1, p+q+1) process restricted by nonlinear constraints on parameters. For this model with a unit root the restricted maximum likelihood estimator (RMLE) of the unit root is strongly consistent and it has the same limiting distribution as the ordinary least squares estimator of the unit root in an AR(1) model tabulated by Dickey and Fuller (1979). A modified RMLE is proposed which has the same limiting properties as the RMLE and is computationally much simpler. Simulation results show that our unit root tests based on the modified RMLE perform very well for small samples and compare favorably with the Said and Dickey (1985) tests with respect to both sizes and powers. An illustrative example from sample survey is given.