首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到6条相似文献,搜索用时 46 毫秒
1.
灰尘、血迹和玻璃在蓝色光照射下,灰尘吸收蓝色光,玻璃透过和反射蓝色光,没有荧光产生,而血迹在蓝色光照射下辐射出绿色荧光,所以,可运用荧光摄影原理消除灰尘手印、记录血迹手印。  相似文献   

2.
Using transmission electron microscopy (TEM) electron irradiation effects were studied for nanogroove-network structured single-crystalline and dendritic polycrystalline Pt nanosheets 50-60 nm in size. These two nanosheets with nearly the same average groove-width or dendritic spacing of 1.3-1.4 nm were prepared from the mixed and single surfactant liquid crystalline templates, respectively. On exposure to electron beam for 20 min at the acceleration voltage of 200 kV, the nanogrooved nanosheets were morphologically little affected, but the dendritic ones were transformed into less branched polycrystalline structures with spacings distributed around ∼1.7 nm. The shape transformation of the latter occurred by the combined mechanism of segmental migration and atomic diffusion. These observations indicate that the nanogrooved Pt nanosheets are highly stabilized by the grooved but crystallographically continuous Pt framework, leading to their extremely high thermo-resistance, in marked contrast to the polycrystalline dendritic structures constructed of crystallographically discontinuous linkages of nanoblocks.  相似文献   

3.
排列互比法用于超精测角的研究   总被引:3,自引:0,他引:3  
作者分析了我互比法现行的两种数据处理方法的缺点,提出了应用最小二乘法原理推导出合理的数据处理方法。本文还首次从理论上阐明了排列互比法测量结果中出现一次谐波系统误差的原因,提出了减少和消除这一些系统误差的方法,并给实验验证。  相似文献   

4.
The methods of numerical simulation and test are combined to analyze the impact behavior of glass fiber reinforced aluminum alloy laminate (GLARE). A new failure criteria is proposed to obtain the impact failure of GLARE, and combined with material progressive damage method by writing code of LS-DYNA. Low velocity impact test of GLARE is employed to validate the feasibility of the finite element model established. The simulation results have been shown that progressive damage finite element model established is reliable. Through the application of the finite element model established, the delamination of GLARE evolution progress is simulated, various failure modes of GLARE during impact are obtained, and the effects of stacking sequence and impactor diameter on the impact damage of GLARE are obtained.  相似文献   

5.
为了实现蓄滞洪区内各洼淀实时洪水调度,考虑到蓄滞洪区内复杂河网与洼淀交错的情况,建立了河道、滞洪区联合计算的一、二维衔接洪水演进数学模型,在考虑铁路、公路、堤防及桥涵等阻水建筑物等复杂边界条件下,采用有限体积法进行离散和求解。结合蓄滞洪区实时洪水调度仿真系统的总体框架,建立了模拟洪水在蓄滞洪区内任意位置的水位、流速、淹没水深、历时等演进过程的一、二维洪水演进数值仿真系统。结合大清河实测资料对东淀滞洪区洪水演进进行了模型验证,结果基本吻合,并应用该系统对大清河滞洪区五洼联合调度方案进行了实时模拟,分析了洼淀联合调度下出现的倒淀现象,对不同方案进行了比较分析,实现了实时的洪水调度分析。  相似文献   

6.
In this paper, the focus is on understanding the properties of nanocomposite hydroxyapatite (HAp)/titania (TiO2) thin films with respect to TiO2 concentration. HAp/TiO2 nanostructured composite thin films with different TiO2 concentrations were successfully fabricated by a simple sol–gel dip coating method. Highly stable HAp and TiO2 sols were prepared prior to the formation of nanocomposite thin films. The coatings were performed under controlled dipping and heat treatment processes. Phase pure HAp and TiO2 were well developed in the nanocomposite after the heat treatment and this was confirmed by XRD. The SEM and AFM analyses of HAp/TiO2 nanocomposite coatings show the variation in the morphology as a consequence different TiO2 concentration. This shows a reduction in the particle size to nanoscale due to the addition of TiO2. The mechanical strength of the coating also increased upon the addition of TiO2 as determined by nanoindentation. The composite thin films with 50 and 80 vol.% of TiO2 show good mechanical strength when compared to other concentrations of TiO2.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号