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排序方式: 共有141条查询结果,搜索用时 15 毫秒
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采用国产春风牌高速摄影机对九运会标枪男子前6名运动员的投掷步弧型助跑方式进行摄影,并运用影片解析,SPSS软件分析系统对数据进行分析处理,研究结果表明:“弧型助跑速度损失并不大;弧型助跑有利于满弓动作的形成;弧型助跑增大了双脚支持面积,提高了支撑的稳定性。 相似文献
124.
Roger Bland 《Cultural Trends》2005,14(4):257-296
This paper looks at the evolution of a new approach to an old problem—that of protecting the heritage of moveable archaeological objects—‘portable antiquities’—in England and Wales. It sets out a brief history of attempts to bring forward legislation to protect such finds, charts the rise of metal detecting as an activity and describes the successful process of changing government policy through the Treasure Act 1996. This led to the Portable Antiquities Scheme which has now received full government funding. The paper looks at how this was achieved through the development of what has been described as the largest community archaeology project in the country, which is starting to change public attitudes towards objects from the past. These two initiatives have in fact started to lead to a change in public attitude towards material from the past. 相似文献
125.
通过对婺江江心洲伍佰滩柱样沉积物(76cm)进行多项磁学参数和重金属含量的测定,得到磁性物质和重金属的垂直分布情况。运用SPSS软件对所得数据作主成分分析,分析表明磁学指标χARM/SIRM和χfd%与Fe、Al、Pb、Ga、V、Ce、Cr、Ni、Cu等重金属含量有较强的相关关系,反映了细晶粒亚铁磁性矿物对重金属的吸附作用。建立了利用磁学参数χARM/SIRM和χfd%推断污染较严重的几种重金属含量的线性回归模型。本研究表明利用磁学参数来快速推断河流沉积物的重金属污染状况是可行的。 相似文献
126.
通过对金川集团有限公司冶炼厂含Ni,Co,Cu等重金属离子废水膜过滤处理工艺的工业性实验数据的分析,得到处理该种废水的合理工艺流程、铁铝复配混凝剂配比和最佳投加量以及种植膜过滤器的运行参数。为工程设计提供了依据,成功的运用到了实践中。 相似文献
127.
Micro-plasma arc surface melting of 0Cr19Ni9 shielded metal arc welding joint with a micro-plasma arc welder produced a thin surface melted layer with a refined microstructure. The surface treatment changed the anodic polarization behavior in 0.5 mol/L H2SO4 solution. The polarization tests showed that for the as-welded joint both the heat-affected zone and the weld metal decreased in resistance to corrosion compared with the as-Received parent material while for the micro-plasma arc surface melted joint the corrosion resistance increased significantly. This increase in corrosion resistance is attributed to the rapid solidification of the melted layer. Rapid solidification of the melted layer refines its microstructure, decreases its microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries.received parent material while for the micro-plasma arc surface melted joint the corrosion resistance increased significantly. This increase in corrosion resistance is attributed to the rapid solidification of the melted layer. Rapid solidification of the melted layer refines its microstructure, decreases its microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries. 相似文献
128.
分析高校科研人员社交网络学术信息交流行为影响因素,有助于提高高校科研人员社交网络学术信息交流行为活跃度,拓宽群体知识面,实现组织内部工作模式创新。文章首先借鉴卢因行为理论构建高校科研人员社交网络学术信息交流行为影响因素模型,结合理性行为理论、顾客感知价值理论等提出八个假设,并采用问卷调查方法收集数据;然后对测量指标进行信度和效度检验,借助结构方程模型分析影响因素并验证假设;最后根据分析结论提出相应建议。通过分析得出行为意向、机会和激励对学术信息交流行为具有正向影响,并从学术社交平台建设、组织内部支持、加强个体学术信息交流意识等方面提出建议。 相似文献
129.
This study assesses the impact of training sheet metal workers in Kenya on their uptake of learned skills and their income. Fifty-eight artisans trained in the construction of metal silos for hermetic grain storage were compared to a random sample of 123 untrained artisans. Results show that two-thirds of the trained artisans were making the silos, half of these in their own workshops and half as employees. The probability of using the skills learned declined with age but increased with previous experience in technical work. The training did not significantly increase the income of employed artisans, but increased the annual income of those who made the silos in their own workshops by KSh315,173 (about US$3,600). The overall impact could be improved by better targeting of trainees, by using apprenticeships as an alternative mode of training, and by encouraging entrepreneurship through business training and provision of credit. 相似文献
130.
Elemental analyses by laser induced breakdown spectroscopy as restoration test on a piece of ordnance 总被引:2,自引:0,他引:2
Laser induced breakdown spectroscopy was used to investigate the composition of a gun found in the Adriatic seabed and kept in the “S. Castromediano” Provincial Museum in Lecce (Italy). Optical emission spectra of the laser-induced plasma from the surface of the piece of ordnance were recorded before and after its restoration. The metal alloy of the gun was determined through the identification of characteristic atomic emissions and confirmed through microanalysis carried out by energy dispersion X-ray spectroscopy. Experimental results evidenced that the gun is of bronze and revealed that elements composing the encrustation and noxious for the object conservation, such as calcium, were removed successfully during the cleaning operation. Performed elemental analyses confirmed that laser induced breakdown spectroscopy is a useful diagnostic tool to test the restoration degree of artworks. 相似文献