排序方式: 共有23条查询结果,搜索用时 31 毫秒
11.
通过论述正确测定水泥标准稠度、用水量、凝结时间及安定性的技术和意义,说明正确的试验方法具有极其重要的作用。同时,提出水泥试验容易出错之处,并给出正确的做法,以供类似工作借鉴。 相似文献
12.
13.
Most efficient indeces and query techniques over XML (extensible markup language) data are based on a certain labeling scheme, which can quickly determine ancestor-descendant and parent-child relationship between two nodes. The current basic labeling schemes such as containment scheme and prefix scheme cannot avoid relabeling when XML documents are updated. After analyzing the essence of existing dynamic XML labels such as compact dynamic binary string (CDBS) and vector encoding, this paper gives a common unifying framework for the numeric-based generalized dynamic label, which can be implemented into a variety of dynamic labels according to the different user-defined value comparison methods. This paper also proposes a novel dynamic labeling scheme called radical sign label. Extensive experiments show that the radical sign label performs well for the initialization, insertion and query operations, and especially for skewed insertion where the storage cost of the radical sign label is better than that of former methods. 相似文献
14.
15.
随着信息与网络技术的飞速发展,各单位办公自动化程度和水平不断提高,作为各类文件材料最终汇集和长期保管地的档案部门如何适应在网络环境下档案工作管理与利用的需要,实行档案数字化是一条切实可行的措施 相似文献
16.
17.
18.
19.
20.
王晓玲 《铁道劳动安全卫生与环保》2009,36(2):68-69
目的了解宝鸡地区铁路机车乘务员身体健康现状。方法采用普查的方式,对1100名机车乘务员(均为男性)进行健康体检。结果该人群高血糖、高血脂的患病率高于国内调查资料(P〈0.05);职业性听力损伤发生率随年龄明显升高。结论该人群高血糖、高血脂有职业性多发倾向;职业性听力损伤具有明显的职业特征。建议对该人群健康危害因素进一步分析,同时开展健康教育,建立健康的生活方式,合理调整作息时间,饮食营养合理化,适当增加体育锻炼,保持身心健康,从而保障铁路运输安全。 相似文献