全文获取类型
收费全文 | 50篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 4篇 |
化学工业 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
轻工业 | 1篇 |
水利工程 | 1篇 |
石油天然气 | 5篇 |
无线电 | 10篇 |
一般工业技术 | 5篇 |
冶金工业 | 2篇 |
原子能技术 | 1篇 |
自动化技术 | 11篇 |
出版年
2022年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有53条查询结果,搜索用时 15 毫秒
1.
《Journal of Great Lakes research》2022,48(3):659-668
Previous studies reported coastal trapped waves (CTWs) in the Caspian Sea (CS). This study deals with the generation mechanisms, the temporal and spatial variability of CTWs in this area, and their transformations during propagation from the origin to the destination using recent measurements and high-resolution numerical simulations. CTWs are observed at all stations with periods of 2–6 days after northerly storms. The Absheron Peninsula, old Sefidrud delta, and Nur coasts were identified as the CTWs prone regions. The generation of CTWs in these locations was confirmed using numerical experiments. The propagation away from the generating location of CTWs was analyzed using a representative real wind storm. In the west part of the CS, the generation mechanism of CTWs is mainly similar to the barotropic Kelvin waves; in contrast, it is similar to the continental shelf waves in the southern shelves. The results can be used to study the contribution of generated CTWs to the transport of sediment and biological materials in all large lakes. 相似文献
2.
3.
超光滑光学基底表面原子力显微镜测试方法 总被引:1,自引:0,他引:1
原子力显微镜(AFM)是评价亚纳米级表面粗糙度σRMS最主要的测试仪器,但其测试结果会因采样条件(采样间距、采样点数)及测量点位置变化而改变。以AFM测试超光滑光学基底随机表面为例,应用累积功率谱理论建立了确定合理采样条件的方法,避免了采样条件选取不当带来的数据丢失或冗余;通过全局优化选取测量点和局部优化选取测量点相结合,降低了样品表面区域性差异给测试结果带来的不确定性,并大大减少了获得可靠测试结果所需的测试量。上述工作为超光滑光学基底AFM测试提供了有效方案。 相似文献
4.
Fourier ring correlation and root-mean-square contrast of pairs of images, taken under identical conditions, were used as criteria of image quality for comparing unfiltered with zero-loss energy-filtered imaging using a TEM equipped with a post-column energy filter. For three different specimens (amorphous carbon film, macromolecules in light negative stain, virus particles in deep negative stain) the dependence of these quantities on electron dose, specimen thickness and defocus was investigated. A model, based on simple assumptions, was used to describe quantitatively their dependence on electron dose and specimen thickness. It was found that energy filtering is most advantageous for low-dose imaging and small defocus values. The gain due to energy filtering strongly increases with specimen thickness, whereby the dependence is linear for light scattering elements. For thick specimens, the gain by energy filtering is more pronounced in the resolution range between 4 and 2 nm than for lower spatial frequencies. 相似文献
5.
6.
7.
E. Clayton Teague 《Journal of research of the National Institute of Standards and Technology》1989,94(6):367-371
An analysis of the uncertainty in measuring the root-mean-square, rms or Rq, value of a periodic waveform which results from the use of a finite record length is presented. Even though the results of the analysis are somewhat as expected, i.e., that the uncertainty is inversely proportional to the number of periods in the record, the explicit relationship between the magnitude of the uncertainty and properties of the waveform does not appear to be available in the literature. The paper first presents an introductory example in terms of the reasonably well known case of bandwidth limited Gaussian waveform to introduce definitions. Following this is an analysis of the periodic waveform using the same approach. It is shown that for a large number of periods, n, in the record length, the normalized three standard deviation of the rms value is given by 3/(8πn). 相似文献
8.
Orientations of proteins in the membranes are crucial to their function and stability. Unfortunately the exact positions of these proteins in the lipid bilayer are mostly undetermined. Here, the spatial orientation of membrane proteins within the lipid membrane was evaluated using a Poisson–Boltzmann solvent continuum approach to calculate the electrostatic free energy of the protein solvation at various orientations in an implicit bilayer. The solvation energy was obtained by computing the difference in electrostatic energies of the protein in water and in lipid/water environments, treating each as an implicit solvent model. The optimal position of transmembrane proteins (TMP) in a lipid bilayer is identified by the minimum in the “downhill” pathway of the solvation energy landscape. The energy landscape pattern was considerably conserved in various TMP classes. Evaluation of the position of 1060 membrane proteins from the orientations of proteins in membranes (OPM) database revealed that most of the polytopic and β-barrel proteins were in good agreement with those of the OPM database. The study provides a useful scheme for estimating the membrane solvation energy made by lipid-exposed amino acids in membrane proteins. In addition, our results tested with the bacterial potassium channel model demonstrated the potential usefulness of the approach in assessing the quality of membrane protein models. The present approach should be applicable for constructing transmembrane proteins–lipid configuration suitable for membrane protein simulations and will have utility for the structural modeling of membrane proteins. 相似文献
9.
针对分段线性表示(即一阶线性函数表示)或分段常数表示(即零阶函数表示)在时间序列近似表示中拟合误差较大的问题,提出时间序列高阶函数分段表示方法。通过建立高阶函数候选集模型,利用拟合误差指标选取最优函数,为保证在分段点处连续,引入断点处约束条件;在分段点选取方式上,设定观测值变化阈值及分段区间阈值,保证压缩率的同时,保留重要点信息。实验结果表明,该算法相对于分段线性表示和分段常数表示,能更好地拟合原始序列。 相似文献
10.