全文获取类型
收费全文 | 161篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 2篇 |
化学工业 | 39篇 |
金属工艺 | 9篇 |
机械仪表 | 12篇 |
建筑科学 | 8篇 |
能源动力 | 9篇 |
轻工业 | 15篇 |
水利工程 | 2篇 |
无线电 | 7篇 |
一般工业技术 | 34篇 |
冶金工业 | 13篇 |
自动化技术 | 24篇 |
出版年
2023年 | 7篇 |
2022年 | 2篇 |
2021年 | 12篇 |
2020年 | 9篇 |
2019年 | 3篇 |
2018年 | 17篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 25篇 |
2012年 | 8篇 |
2011年 | 14篇 |
2010年 | 5篇 |
2009年 | 16篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2003年 | 4篇 |
1999年 | 1篇 |
1991年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 15 毫秒
1.
Ahmad Zamani Gharaghooshi Akbarinezhad Esmaeil Esmaeili Naser Neshati Jaber 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(1):153-167
Protection of Metals and Physical Chemistry of Surfaces - In this study, the inhibitive performance of 2-mercaptobenzothiazole (2MBT) and 2-aminobenzothiazole (2ABT) were investigated on API-5L X60... 相似文献
2.
We consider an initial-boundary-value problem for a time-fractional diffusion equation with initial condition u0(x) and homogeneous Dirichlet boundary conditions in a bounded interval [0, L]. We study a semidiscrete approximation scheme based on the pseudo-spectral method on Chebyshev–Gauss–Lobatto nodes. In order to preserve the high accuracy of the spectral approximation we use an approach based on the evaluation of the Mittag-Leffler function on matrix arguments for the integration along the time variable. Some examples are presented and numerical experiments illustrate the effectiveness of the proposed approach. 相似文献
3.
Microstructural evolution of AZ31 magnesium alloy welds without and with the addition of titanium powders during resistance
spot welding was studied using optical microscopy, scanning electron microscopy, and transmission electron microscopy (TEM).
The fusion zone of AZ31 magnesium alloy welds could be divided into columnar dendritic zone (CDZ) and equiaxed dendritic zone
(EDZ). The well-developed CDZ in the vicinity of the fusion boundary was clearly restricted and the coarse EDZ in the central
region was efficiently refined by adding titanium powders into the molten pool, compared with the as-received alloy welds.
A microstructural analysis showed that these titanium particles of approximately 8 μm diameter acted as inoculants and promoted
the nucleation of α-Mg grains and the formation of equiaxed dendritic grains during resistance spot welding. Tensile-shear testing was applied
to evaluate the effect of titanium addition on the mechanical properties of welds. It was found that both strength and ductility
of magnesium alloy welds were increased after the titanium addition. A TEM examination showed the existence of an orientation
matching relationship between the added Ti particles and Mg matrix, i.e.,
[ 0 1[`1]0 ]\textMg // [ 1[`2] 1[`3] ]\textTi \textand ( 000 2 )\textMg // ( 10[`1]0)\textTi \left[ {0 1\bar{1}0} \right]_{\text{Mg}} // \, \left[ { 1\bar{2} 1\bar{3}} \right]_{\text{Ti}} \,{\text{and}}\,\left( {000 2} \right)_{\text{Mg}} // \, ( 10\bar{1}0)_{\text{Ti}} in some grains of Ti polycrystal particles. This local crystallographic matching could promote heterogeneous nucleation of
the Mg matrix during welding. The diameter of the added Ti inoculant should be larger than 1.8 μm to make it a potent inoculant. 相似文献
4.
Optimizing the mechanical and physical properties of thermoplastic starch via tuning the molecular microstructure through co‐plasticization by sorbitol and glycerol 下载免费PDF全文
Nowadays, environmental hazards caused by plastic wastes are a major concern in academia and industry. Utilization of biodegradable polymers derived from renewable sources for replacing common petroleum‐based plastics is a potential solution for reducing the problem. In this regard, starch has become one of the most promising alternatives to non‐biodegradable polymers for depleting plastic waste thanks to its low expense, abundance, renewability and biodegradability. However, the main drawbacks of starch are its poor processability, weak mechanical properties and severe hydrophilicity. In this work, thermoplastic starch (TPS) samples have been prepared using glycerol and sorbitol as co‐plasticizers in a laboratory co‐rotating twin screw extruder. Based on the mechanical test results, glycerol caused higher elongation to break but had lower tensile strength and elastic modulus compared to sorbitol plasticized starch. Fourier transform infrared spectroscopy and DSC results indicated that the hydrogen bond interaction between starch chains and plasticizers could be improved by replacing glycerol by sorbitol, which resulted in higher resistance against retrogradation proved by XRD results. TGA illustrated that the higher the sorbitol to glycerol ratio was, the more stable was the TPS. Using a proper amount of plasticizers (42 wt% total plasticizer, sorbitol to glycerol ratio 2:1) led to the preparation of a TPS sample with optimized properties including enhanced mechanical properties, high thermal stability, strong hydrogen bond formation and high resistance against retrogradation. © 2017 Society of Chemical Industry 相似文献
5.
Rapid growth of digital data and their security concerns increases the significance of enhancing advanced encryption techniques. Encryption is the backbone of secure communication in networks and the physical process of scrambling and permuting data in order to make them impossible to understand for unauthorized users. This paper proposes a novel audio signal encryption method, based on a mixture of three chaos functions. Due to the reversibility of the chaos functions, the decryption process is the inverse of the encryption process. This method was applied to audio signals with various sizes and the encoded messages were compared to the original ones. Simulation results and theoretical analyses show that the proposed approach offers a significant gain in terms of robustness and computational complexity. 相似文献
6.
7.
Silicon - Metformin (MF) and L. albuman are used to treat type 2 diabetes. Diabetes causes problems such as blindness and albumin excretion. In this study, metformin, L. albuman and a composition... 相似文献
8.
M. Esmaeili S. Yari 《Applicable Algebra in Engineering, Communication and Computing》2009,20(2):159-173
Generalized quasi-cyclic (GQC) codes are defined by generator matrices comprised of circulant matrices of lengths not necessarily
identical. A decomposition of these codes is given by using the Chinese reminder theorem. The focus is to characterize ρ-generator GQC codes in details. A good lower bound on the minimum distance of such a code in terms of the minimum distance
of the constituent codes is given. Construction methods are given and a set of GQC codes is provided that from minimum distance
perspective are optimal codes among the known linear codes having the same length and dimension. 相似文献
9.
A. Esmaeili H.R. Zareie Rajani M. Sharbati M.K. Besharati Givi M. Shamanian 《Intermetallics》2011,19(11):1711-1719
In this paper, the intermetallic compounds formation during dissimilar friction stir welding of brass to aluminum 1050 and its effect on the mechanical behavior of joint were studied. Scanning Electron Microscopy (SEM), Energy dispersive spectroscopy analysis (EDS) and X-ray Diffraction analysis were used to characterize intermetallics. In addition, tensile tests and microhardness measurements were performed to evaluate mechanical properties. The results showed that utilizing rotation speeds higher than 400 rpm leads to gradual formation of intermetallic compounds in the stir zone and at the interface. CuAl2 is the dominant compound in the composite structure of the stir zone, whereas four intermetallic bands are detected at the interface. From aluminum to brass, two middle layers were formed. Then, CuAl2, Cu9Al4 and CuZn were detected. The increase in rotation speed is accompanied by thickening and development of interfacial intermetallic compounds. The optimum rotation speed of 450 rpm yielded a narrow interfacial intermetallic compound and a lamellar composite structure within the stir zone which enhances the tensile strength of the weld. On the other hand, further increase of rotation speed lowers the tensile strength of the weld which is accompanied by disappearance of lamellar composite structure, increment of weld defects and thickening of interfacial intermetallic layer. 相似文献
10.