全文获取类型
收费全文 | 83篇 |
免费 | 3篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 20篇 |
金属工艺 | 2篇 |
机械仪表 | 3篇 |
建筑科学 | 1篇 |
能源动力 | 3篇 |
轻工业 | 5篇 |
石油天然气 | 1篇 |
无线电 | 12篇 |
一般工业技术 | 21篇 |
冶金工业 | 5篇 |
原子能技术 | 1篇 |
自动化技术 | 10篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
排序方式: 共有86条查询结果,搜索用时 15 毫秒
1.
The primary aim of this paper is to present results describing in detail the behaviour of ±45° E-glass/MY750 (GRP) tubes, of various wall thicknesses, subjected to equal biaxial tension–compression loading, generated under combined internal pressure and axial compression. The role played by the non-linear lamina shear has also been assessed by comparing various shear stress–strain curves for embedded laminae (extracted from tests on ±45° tubes subjected to circumferential: axial stress ratios SR=1:0, 1:−1 and 2.3:−1) with that of an ‘isolated’ lamina (measured from torsion of 90° tubes). Extracted shear failure strains, for embedded laminae, were more than four fold larger than those measured at ultimate failure for an ‘isolated’ lamina. Soft characteristics were observed in the embedded lamina and these were believed to be due to interaction between early matrix damage initiation (and propagation) and shear. Factors affecting the behaviour of the tubes, such as bulging, scissoring, thermal stresses and stress variation through the thickness are discussed. 相似文献
2.
Effect of polyethylenimine addition and washing on stability and electrophoretic deposition of Co3O4 nanoparticles 下载免费PDF全文
Ali Asghar Sadeghi Ghazvini Ehsan Taheri‐Nassaj Babak Raissi Reza Riahifar Maziar Sahba Yaghmaee 《Journal of the American Ceramic Society》2018,101(2):553-561
In this work, the parameters of cobalt oxide suspension such as conductivity, zeta potential, particle size, stability, and finally the electrophoretic behavior of particles in the absence and presence of polyethylenimine (PEI) in acetone medium were investigated. Also, the effects of washing on the stability and electrophoretic deposition of Co3O4 were studied. Characterization of the obtained layer by optical microscopy revealed that there was no deposition in the suspension without PEI, while a uniform layer was formed in the presence of PEI additive. Scanning electron microscopy (SEM) results confirmed the uniformity of layer obtained in acetone using PEI additive. Moreover, SEM results demonstrated that more porous microstructures were obtained at longer deposition durations. The difference in the porosity of the layers, as indicated by the SEM micrographs, is attributed to increase in the deposition time. 相似文献
3.
Abstract. In this article, we extend the earlier work of Freeland and McCabe [Journal of time Series Analysis (2004) Vol. 25, pp. 701–722] and develop a general framework for maximum likelihood (ML) analysis of higher‐order integer‐valued autoregressive processes. Our exposition includes the case where the innovation sequence has a Poisson distribution and the thinning is binomial. A recursive representation of the transition probability of the model is proposed. Based on this transition probability, we derive expressions for the score function and the Fisher information matrix, which form the basis for ML estimation and inference. Similar to the results in Freeland and McCabe (2004) , we show that the score function and the Fisher information matrix can be neatly represented as conditional expectations. Using the INAR(2) specification with binomial thinning and Poisson innovations, we examine both the asymptotic efficiency and finite sample properties of the ML estimator in relation to the widely used conditional least squares (CLS) and Yule–Walker (YW) estimators. We conclude that, if the Poisson assumption can be justified, there are substantial gains to be had from using ML especially when the thinning parameters are large. 相似文献
4.
In this work, a conformational analysis of (thioxosilyl) ethyleneselenol was performed using several computational methods, including density-functional theory (DFT) (B3LYP), MP2 and G2MP2. Harmonic vibrational frequencies were estimated at the same levels to confirm the nature of the stationary points found and also to account for the zero point vibrational energy correction. MES-1 and TES-1 conformers exhibit hydrogen bonding. This feature, although is not the dominant factor in the stability of conformers, appears to be of foremost importance to define the geometry of the molecule. Two intramolecular hydrogen bonds established between the polar groups were identified by the structural geometric parameters. These involved the thiol and selenol functional groups and were identified and characterized by the frequency shift in their stretching vibration modes. Furthermore, the excited-state properties of intramolecular hydrogen bonding have been investigated theoretically using the time-dependent DFT method. The influence of the solvent on the stability order of conformers and the strength of intramolecular hydrogen bonding was considered using the PCM (polarizable continuum model), SCI-PCM (self consistent isodensity-polarizable continuum model) and IEF-PCM (integral equation formalism-polarizable continuum model) methods. The “atoms in molecules” theory of Bader was used to analyze critical points and to study the nature of hydrogen bond in these systems. Natural bond orbital (NBO) analysis was also performed for better understanding the nature of intramolecular interactions. The calculated highest occupiedmolecular orbital and lowest unoccupied molecular orbital energies show that charge transfer occur within the molecule. Further verification of the obtained transition state structures was implemented via intrinsic reaction coordinate analysis. Calculations of the 1H NMR chemical shift at the GIAO/B3LYP/6–311++G** level of theory are also presented. 相似文献
5.
6.
Josephson fluxonic bipolar junction transistor (JFBJT) has been proposed as a superconducting amplifying element. The results on a simple realization of this device are provided to demonstrate its working principle. These experiments demonstrate that JFBJT provides current gain without suffering from the problems associated with the regular long junction vortex flow transistors. In particular, no resonance structure is present in its I-V characteristics and its impedance can be matched to any load without degradation of its characteristics. Suggestion is made on how a practical device can be fabricated. 相似文献
7.
Abderrahmane Aït Kaddour Evane Grand Nathalie Barouh Bruno Bara Pierre Villeneuve Bernard Cuq 《European Journal of Lipid Science and Technology》2006,108(12):1037-1046
The present study was aimed at determining the ability of near‐infrared (NIR) spectroscopy to in situ describe fat oxidation kinetics in three different cereal‐based products: salted crackers (20% saturated palm oil and lauric oil, sprayed on surface); healthy crackers (10% unsaturated rapeseed oil, homogeneously distributed inside the product matrix); and moist pasteurised Asian noodles (1.5% unsaturated rapeseed oil, sprayed on surface). Products were stored under accelerated oxidation conditions at 40 °C. Lipid oxidation rates were determined from peroxide value (PV) measurements. We observed no significant changes in PV for the dry crackers (3 meq/kg after 60 days), a slight linear increase in PV for the healthy crackers (40 meq/kg after 60 days), and a rapid increase for the Asian noodles (80 meq/kg after 20 days). The NIR spectra were recorded between 1000 and 2500 nm by using a Fourier Transform NIR spectrometer, using an external probe. Measurements were done directly in situ on the product, on the ground samples, and on the extracted fat phase. The analysis of NIR spectral data by PLS statistical methods demonstrated some correlation trends (R2 = 0.575–0.897; RMSEC = 17–55%) for the products having a significant increase in PV. It was not possible to propose predictive models to calculate the oxidation rate. 相似文献
8.
Fluorescence spectroscopy coupled with independent components analysis to monitor molecular changes during heating and cooling of Cantal‐type cheeses with different NaCl and KCl contents 下载免费PDF全文
9.
S.?Ghashghaie A.?M.?Bazargan M.?Esmaeilpour?Ganji E.?MarzbanradEmail author C.?Zamani B.?Raissi M.?Keyanpour-rad M.?A.?Bahrevar 《Journal of Materials Science: Materials in Electronics》2011,22(9):1303-1307
In present study, the behavior of electrospun ZnO nanofibers under the application of low frequency alternating (AC) electric
fields within the range of 1 Hz–20 kHz was investigated using planar parallel electrodes. In the first stage, ZnO nanofibers
with diameters up to 100 nm were prepared by electrospinning. At 1 Hz, the strong electric field-induced fluid flow due to
charge redistribution around the electrode swept the fibers on the electrode surface farther from the edges. As the frequency
was increased to 1 kHz, most depositing fibers accumulated on the electrode edges and in the meantime, a small fraction of
them was pushed into the surface as a result of AC electroosmosis effect. Above 1 kHz, the fibers were assembled within the
electrode gap bridging the interelectrode space. The dielectrophoresis force was considered responsible for the assembly and
relative alignment of ZnO nanofibers above 1 kHz. 相似文献
10.
Proportional integral-fractional filter controller design for first order lag plus time delay system
Kaddour Gherfi Abdelfatah Charef Hadj Ahmed Abbassi 《International journal of systems science》2018,49(8):1654-1673
In this work, a design approach of proportional integral-fractional filter (PI-FF) controller for first order plus time delay (FOPTD) system is proposed in order to enhance the feedback control system performances characteristics. The controller design method is drawn up such that the transfer function of the overall closed-loop system is equivalent to the transfer function of the general fractional Bagley–Torvik reference model whose behaviour ranges from relaxation to oscillation for different values of the fractional order derivative and the damping ratio-like parameter. The tuning parameters of the PI-FF controller are derived analytically from the FOPTD process model and the general fractional Bagley–Torvik reference model parameters. Illustrative examples were presented to test the effectiveness and the usefulness of the proposed PI-FF controller on the feedback control system performance characteristics enhancement. 相似文献