全文获取类型
收费全文 | 155篇 |
免费 | 13篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 41篇 |
金属工艺 | 12篇 |
机械仪表 | 5篇 |
能源动力 | 3篇 |
轻工业 | 2篇 |
无线电 | 16篇 |
一般工业技术 | 66篇 |
冶金工业 | 4篇 |
自动化技术 | 20篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 9篇 |
2012年 | 16篇 |
2011年 | 18篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 17篇 |
2007年 | 5篇 |
2006年 | 12篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 6篇 |
排序方式: 共有169条查询结果,搜索用时 46 毫秒
61.
Harald Rösner Christian Kübel Yulia Ivanisenko Lilia Kurmanaeva Sergiy V. Divinski Martin Peterlechner Gerhard Wilde 《Acta Materialia》2011,59(19):7380-7387
Aberration-corrected transmission electron microscopy was used to provide structural information on a triple junction in nanocrystalline Pd. This triple junction consists of two intersecting Σ3 twin boundaries with a Σ9 grain boundary and is connected to a quadruple point via the Σ9 grain boundary. A comprehensive strain analysis of this triple junction using geometric phase analysis is presented and compared with a molecular dynamics simulation. The main results are: (i) the strain field of the core of the triple junction shows dislocation character and extends over a distance of about 0.5 nm; (ii) the intersecting boundaries result in a net translation of , which corresponds to a Burgers vector of an dislocation in the fcc lattice; (iii) a disclination emerging from the triple junction along the Σ9 grain boundary is balanced by a disclination of opposite sign emerging from the quadruple point. Based on the observation that the core of the triple junction can be described by the strain field of a dislocation, its energy was estimated using to be about 1.7 × 10−9 J m−1. The presence of a disclination dipole is thought to be essential for stabilization of the structure observed. 相似文献
62.
Field emission from various types of nanotubes is studied by propagating the electronic density in real space and time using time-dependent density functional theory. Capped (5, 5) C, BN, SiC, Si, and GaN nanotubes are considered. The GaN, SiC, and Si nanotubes were found to be significantly better field emitters than C and BN nanotubes, both in terms of current magnitude and sharpness of peaks in the energy spectra. By analyzing the electronic structure of the various systems it is seen that the nanotubes with the highest currents have electron densities that extend significantly from the nanotube in the emission direction. 相似文献
63.
Simulation of fresh concrete flow using Discrete Element Method (DEM): theory and applications 总被引:1,自引:0,他引:1
Viktor Mechtcherine Annika Gram Knut Krenzer Jörg-Henry Schwabe Sergiy Shyshko Nicolas Roussel 《Materials and Structures》2014,47(4):615-630
This article provides an overview of the development and the contemporary state of research in the field of simulating fresh concrete flow using the Discrete Element Method (DEM). First, this work originating from TC 222-SCF simulation of fresh concrete flow, covers the mathematical methodology, the identification of the model parameters and the link between the rheological properties of fresh concrete and the parameters of DEM-based models. Various examples of the estimation of model parameters and calibration of the model were demonstrated, followed by verifications by comparing the numerical results and the corresponding predictions by analytical formula and laboratory experiments. Furthermore, software used in concrete engineering and existing industrial applications of the developed particle models were described, showing the potential of DEM. 相似文献
64.
Sergiy Korablov Kazunori Yokosawa Taku Sasaki Dmytro Korablov Akira Kawasaki Koji Ioku Emile H. Ishida Nakamichi Yamasaki 《Journal of Materials Science》2007,42(18):7939-7949
Hydrothermal growth of diamond particles and films was achieved during interaction of a liquid organic precursor (C2H3Cl3) and 10 M NaOH in the presence of diamond or cubic BN seeds at the temperature 300 °C and 1 GPa pressure. Synthesized diamond
was thoroughly characterized by TG-DTA, SEM, EDX, TEM, Raman spectroscopy and had (220) preferable orientation according to
XRD pattern in the case of the film. 相似文献
65.
We consider a network representation of the stock market data referred to as the market graph, which is constructed by calculating cross-correlations between pairs of stocks based on the opening prices data over a certain period of time. We study the evolution of the structural properties of the market graph over time and draw conclusions regarding the dynamics of the stock market development based on the interpretation of the obtained results. 相似文献
66.
Benoit N Schröder S Yulin S Feigl T Duparré A Kaiser N Tünnermann A 《Applied optics》2008,47(19):3455-3462
The extreme-ultraviolet (EUV)-induced oxidation of Mo/Si multilayer mirrors was characterized by several methods: EUV reflectivity, x-ray photoelectron spectroscopy, small-angle x-ray reflectometry, atomic force microscopy, and EUV scattering measurements. Based on the results of the different investigation techniques, an oxidation model was developed to explain the degradation of the mirrors under EUV radiation. 相似文献
67.
Ralph Rosenbaum Sergiy Balanetskyy Benjamin Grushko Bartosz Przepiórzyński 《Journal of Low Temperature Physics》2008,150(1-2):82-100
Electrical resistivities of two icosahedral (I) Al-Pd-Re alloys have been measured between room temperature and mK temperatures.
One quasicrystalline (QC) polygrain Al-Pd-Re sample exhibited insulating behavior in its resistivities, increasing by a factor of r=R(4 K)/R(300 K)=7.76; its room temperature resistivity was 9,890 μΩ cm. A “phenomenological” expression fitted the conductivity data
well between 300 K to 0.5 K. Below 0.4 K a crossover to an activated variable-range hopping law was observed. Low temperature
magnetoresistance ratio data and fits using the wave function shrinkage theory are presented. A second QC Al-Pd-Re sample
had a small resistance temperature ratio r=2.12. The room temperature resistivity was extremely large, ρ(300 K)≈40,980 μΩ cm. Its conductivity could be described well using a simple temperature power law between 300 K to 20 K.
Below 20 K there was a crossover to a new behavior. Below 1 K, the conductivity could be fitted using a very weakly insulating
power law where σ(T)≈11.37T
0.032 in (Ω cm)−1, suggesting that this sample is located just below the metal-insulator transition. The magnetoconductivity data could not
be fitted successfully using the 3D weak localization (WL) theory and inserting into it physical and realistic fitting magnitudes
for the inelastic magnetic field B
in.
相似文献
68.
69.
70.
Lapchuk AS Shylo SA Nevirkovets IP 《Journal of the Optical Society of America. A, Optics, image science, and vision》2008,25(7):1535-1540
A local plasmon resonance on a metal wedge is studied by using the Meixner approach [J. Meixner, IEEE Trans. Antennas Propag.AP-20, 442 (1972)]. It is found that the singular field behavior of a local plasmon resonance as a function of the distance from the edge of the wedge is sensitive to the wavelength and wedge angle, and ranges from a dramatic increase in amplitude close to its theoretical limit to pure oscillatory behavior with only minor amplitude variation. Field singularities for gold, silver, and aluminum wedges are calculated. It is shown that, unlike an ideal-conductor wedge, the real part of the power index of the electric field singularity does not decrease monotonically as a function of the wedge angle, but has a minimum for some angle depending on the wavelength and material parameters. If the dielectric surrounding the wedge has a positive permittivity equal to the absolute value of that of the metal, and hence satisfies the plasmon resonance condition, then the electric field has a peculiar behavior for a wedge whose shape is close to the flat surface. 相似文献