沥青混凝土摊铺机熨平机构的动力学实验研究

为研究沥青混凝土摊铺机的熨平板结构参数和其有关振动压实部件的运动参数的关系, 对国内新生产的一种摊铺机的熨平板机构进行了动力学实验研究－ 得到了在一种激振频率下前后压实梁及熨平板平台在不同受压介质刚度下的加速度信号和其变化特征等, 揭示了压实梁等在不同压实介质下的运动规律     

计算机硬件实验教学的几个问题

指出我国高校计算机应用专业在计算机硬件实验教学上普遍存在的一些问题,分析了其产生的原因,并提出了一些解决这些问题的措施     

不分明化拓扑中的仿S—闭性

在不分明化拓扑中定义了正闭集,并用正则闭集和半开集刻画了仿Ｓ－闭性。．     

航弹风标式导引头失调角测量

目的　研究航弹风标式导引头失调角风洞测量技术,给出一个外形的失调角; 方法　将特制的小型磁敏角度传感器装于风标式导引头内,测量风标式导引头纵轴与弹体纵轴的夹角,经处理后得到失调角; 结果　在Ｍａ＝ ０．６～１．０,α＝ ０～２８°范围内,得到了失调角随Ｍａ,α变化的实验数据; 结论　所用方法能得到较准确的风标式导引头失调角;失调角产生于弹体前段对风标式导引头的非对称气动力干扰;失调角量值不大,小攻角时为负值,大攻角时为正值;     

光栅示波器的实验

介绍了光栅显示原理和光栅示波器的组成框图。作为一种尝试,在附加一些简单电路的情况下,将一台黑白电视机改装成多踪光栅示波器。     

物理实验教学中突出培养学生能力的探讨

根据物理实验教学特点,从采用启发式教学,加强实验环节,开设设计性实验等方面对提高学生能力进行探讨．     

放大电路高频响应分析再探

在分析放大电路的上限截止频率时,通常用密勒定理对共射电路进行单向化等效,可简化计算过程。但是分析表明,密勒定理不能解释共基和共集电路的上限截止频率比共射电路高的原因。在网络的上限截止频率附近,用主极点函数来表示网络的传递函数,就可以用网络的开路时间常数和表示网络上限截止频率的时间常数。运用主极点方法分析放大电路的上限截止频率,一眼即可看出,共基和共集电路的开路电阻远小于共射电路的开路电阻,因此它们的开路时间常数和比共射电路的小,它们的高频响应效果自然优于共射放大电路。由此可见,用放大电路的开路时间常数和分析上限截止频率,物理概念清晰,它适用于各种放大电路的高频响应分析。     

180t顶吹转炉溅渣护炉工艺冷态模拟试验

采用冷态模拟试验,通过测定溅到转炉炉衬上的渣量多少,确定最佳操作工艺参数·结果是在１１％渣量及２３０ｍ３·ｈ－１,２６８ｍ３·ｈ－１顶吹标准状态气体流量条件下,炉衬表面和炉帽部位的最佳溅渣枪位分别是１５５ｍｍ,１６５ｍｍ左右和１２５ｍｍ,１４５ｍｍ左右·     

Impact of climate change on wetland ecosystems: A critical review of experimental wetlands

Climate change is identified as a major threat to wetlands. Altered hydrology and rising temperature can change the biogeochemistry and function of a wetland to the degree that some important services might be turned into disservices. This means that they will, for example, no longer provide a water purification service and adversely they may start to decompose and release nutrients to the surface water. Moreover, a higher rate of decomposition than primary production (photosynthesis) may lead to a shift of their function from being a sink of carbon to a source. This review paper assesses the potential response of natural wetlands (peatlands) and constructed wetlands to climate change in terms of gas emission and nutrients release. In addition, the impact of key climatic factors such as temperature and water availability on wetlands has been reviewed. The authors identified the methodological gaps and weaknesses in the literature and then introduced a new framework for conducting a comprehensive mesocosm experiment to address the existing gaps in literature to support future climate change research on wetland ecosystems. In the future, higher temperatures resulting in drought might shift the role of both constructed wetland and peatland from a sink to a source of carbon. However, higher temperatures accompanied by more precipitation can promote photosynthesis to a degree that might exceed the respiration and maintain the carbon sink role of the wetland. There might be a critical water level at which the wetland can preserve most of its services. In order to find that level, a study of the key factors of climate change and their interactions using an appropriate experimental method is necessary. Some contradictory results of past experiments can be associated with different methodologies, designs, time periods, climates, and natural variability. Hence a long-term simulation of climate change for wetlands according to the proposed framework is recommended. This framework provides relatively more accurate and realistic simulations, valid comparative results, comprehensive understanding and supports coordination between researchers. This can help to find a sustainable management strategy for wetlands to be resilient to climate change.     

最优的单纯形-中心设计

对于一般的ｑ－１维正规单纯形利益区域和多重线性多项式模型,给出了Ａ 最优的混料设计,Ａ 最优的混料设计的柱点是所有的正规单纯形的各类中心·令ｒｉ(ｉ＝１,２,…,ｑ)表示每个第ｉ类中心点上的设计测度,给出了以ｒｊ／ｒｑ(ｊ＝１,２,…,ｑ－１)形式表示的Ａ 最优测度比,按此测度比给出的广义单纯形中心设计是Ａ 最优的