Effects of mechanical vibration on root development of Actinidia chinensis plantlet

The root development of Actinidia chinensis plantlets was studied in exposure to environmental stress of mechanical vibration at respectively 1 Hz, 2 Hz, 3 Hz, 4 Hz and 5 Hz. The plantlets exposed to vibration stimuli at all those frequencies have a larger total number and a larger total length of roots and a smaller permeability of root plasma-membrane, compared with those cultivated in an environment without vibration stress. Vibration at respectively 1 Hz, 2 Hz, 3 Hz and 4 Hz enhances root activity and the 3 Hz vibration is the most favorable. There is an obvious negative correlation between root activity and permeability of root plasma-membrane. The effects may be explained by the likelihood that mechanical vibration at an appropriate frequency facilitates roots’ absorbing water and minerals which are indispensable to inducing and synthesizing in roots some active substances favorable to growth. Nevertheless, overstress damages the integrity of root plasm-membrane, increases the permeability, and results in the disability of protecting root cells.     

参量激励作用下非线性系统的二参数分叉

参量激励下的Duffing-van der Pol系统是一个多参数的非线性系统,本文研究了该系统的二参数共振分叉问题,利用多尺度方法得到了系统的一次近似平均方程和分叉响应方程.分析了分叉方程的解及其在二分叉参数平面上的分布.研究了零解的稳定性.     

推行出境免税制以促进我国经济发展

出境免税政策是针对旅游者以及短期出境交流人员在购买商品方面所给予的优惠政策,在欧盟国家已实行多年。若在我国实施出境免税政策可以极大地促进我国经济、尤其是对外贸易的发展,它的特殊作用是其他政策难以起到的,有利于我国国民经济整体实力的提高。     

振动合成原理实验的计算机模拟

利用计算机首先进行简谐振动实验的模拟，然后对振动合成原理实验进行模拟，并给出简谐振动实验和振动合成原理实验的计算机模拟源程序，为在计算机上进行物理实验教学、演示实验以及课件制作提供编程的依据．     

辩文学功利之与文学自觉

我们所讨论的“文学的自觉”中“文学”这个概念应是“文学活动”,而“文学活动”是主客观的融合;主客观的融合形成的必然结果就是既有确定性的一面,也有不确定性的一面;因而将是否与经学分家与是否具有功利性作为“文学自觉”的标准是不合适的。     

Winkler地基上四边自由矩形薄板的1/3次亚谐共振与混沌分析

研究Winkler地基上四边自由矩形薄板的复杂运动,按照弹性力学理论建立Winkler地基上四边自由受简谐激励作用矩形薄板的动力学方程;利用Galerkin方法将其转化为非线性振动方程;应用非线性振动的多尺度法求得了系统满足1/3次亚谐共振情况时的一次近似解,并进行数值计算;分析激励、调谐值、阻尼等对系统响应曲线的影响;应用Floquet理论分析了系统的稳定性问题;应用Melnikov方法得到了系统可能产生混沌运动的条件。     

GAF型通风机改造

针对GAF型通风机在生产运行中存在的问题进行了分析研究,并从理论和技术上提出了具体的改造方案。通过实际应用,产生了良好的效应确保了煤矿安全生产。     

Contested childhoods across borders and boundaries: Insights from curriculum provisions in Northern Ireland and the Irish Free State in the 1920s

Conceptualisations and constructs of children and childhood are temporally and contextually grounded. Historical documents are rich sources of insight and understanding regarding how children were understood, valued and treated at various times by particular societies. This article explores the conceptualisation of children and childhood in the 26-county Irish Free State (South) and the 6-county Northern Ireland (North) in the 1920s following the partition of Ireland, through the lens of educational documentation, primarily national primary school curricula. The focus on both jurisdictions is interesting in the context of partition, exploring the sometimes divergent and often convergent ways in which children were conceptualised across borders and boundaries. This article reveals, using Sorin and Galloway’s framework as a conceptual and analytical tool, that conceptualisations of children were broadly similar in the North and South but differed in their focus and enactment in both fledgling states. These disparities are largely attributable to the very different political, social and religious orientations of both jurisdictions and the use of education as a vehicle for nation-building, as well as identity and gender formation. The article also explores alternative conceptualisations of children in education policy in the North and South by presenting case study ‘outliers’ of educational provision. A century since partition, conclusions and implications are noted that resonate with contemporary elements of convergence and divergence on educational policy and the conceptualisation of children across the island of Ireland.     

聚碳酸酉眇聚对苯二甲酸丁二酯合金无卤阻燃研究进展

综述了聚碳酸酯（PC）、聚对苯二甲酸丁二酯（PBT）及其合金的无卤阻燃研究的进展,分别论述了硫系、硅系、氮系、磷系、硼系等多个体系的阻燃机理,对其优缺点进行了评价,介绍了PC／PBT无卤阻燃发展的方向。     

强夯振动影响范围研究综述

强夯法加固地基具有效果显著、设备简单、适用范围广、经济易行等优点,但强夯振动对周围环境和建筑物产生的不良影响也不容忽视。文章分析了强夯对周围建筑物产生影响的原因,确定了强夯振动影响范围的指标和方法。