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1.
2.
Venkateswaran R. Mazumder P. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》1993,1(1):31-45
The authors present the issues involved in the design of a special-purpose processing array system, called HAM, which accelerates computationally intensive wire routing tasks. It is especially suited for double-sided surface-mounted boards, which require complex three-dimensional search operations over multiple wiring planes. The novel features of the design include a hexagonal interconnection scheme to improve workload distributions during multilayer concurrent search operations and the VLSI custom design of the processors. Particular emphasis has been placed on the demands of maze routing. A cell-address propagation scheme, which is quite different from the traditional grid-coordinate approach, is discussed. It provides rapid lookup of pertinent routing information and can be extended to any distributed memory multiprocessor system. A global pipelining scheme of cell updates and expands is discussed. Experimental results are presented relating the speedup to various criteria for two different modes of parallel wave propagation 相似文献
3.
Bikramjit Basu T. Venkateswaran Doh-Yeon Kim 《Journal of the American Ceramic Society》2006,89(8):2405-2412
In a recent work, 1 we have reported the optimization of the spark plasma sintering (SPS) parameters to obtain dense nanostructured 3Y-TZP ceramics. Following this, the present work attempts to answer some specific issues: (a) whether ZrO2 -based composites with ZrB2 reinforcements can be densified under the optimal SPS conditions for TZP matrix densification (b) whether improved hardness can be obtained in the composites, when 30 vol% ZrB2 is incorporated and (c) whether the toughness can be tailored by varying the ZrO2 –matrix stabilization as well as retaining finer ZrO2 grains. In the present contribution, the SPS experiments are carried out at 1200°C for 5 min under vacuum at a heating rate of 600 K/min. The SPS processing route enables retaining of the finer t -ZrO2 grains (100–300 nm) and the ZrO2 –ZrB2 composite developed exhibits optimum hardness up to 14 GPa. Careful analysis of the indentation data provides a range of toughness values in the composites (up to 11 MPa·m1/2 ), based on Y2 O3 stabilization in the ZrO2 matrix. The influence of varying yttria content, t -ZrO2 transformability, and microstructure on the properties obtained is discussed. In addition to active contribution from the transformation-toughening mechanism, crack deflection by hard second phase brings about appreciable increment in the toughness of the nanocomposites. 相似文献
4.
The dissolution rate coefficients of Cr‐substituted (0‐20 at.% Cr) iron oxides viz. hematite and magnetite were determined by using an inverse cubic rate (ICR) law applicable for spherical particles as well as by a general kinetic equation (GKE) applicable for polydispersed particles. An attempt is made to compare both the treatments for different kinds of dissolution profiles obtained by employing oxides with narrow particle size distribution in V(II)‐EDTA and citric acid‐EDTA‐ascorbic acid formulations at 353±5K. The dissolution profiles could be classified into three types based on the nature of oxide and formulations. It is observed that both ICR and GKE treat the dissolution course as a function of decrease in fraction of undissolved mass, m/m0. The dissolution rate coefficients determined by ICR and GKE have shown the similar trend of decrease with increasing Cr content of the oxides and was ascribed to lattice stabilization. 相似文献
5.
P. Venkateswaran Zhi-Hui Xu Xiaodong Li A. P. Reynolds 《Journal of Materials Science》2009,44(15):4140-4147
A series of friction stir welds was produced between heat treated Al–Mg–Si and strain hardened Mg–Al–Zn alloy sheets. Weld
evaluation by transverse tensile testing showed a wide range of strengths and all the failures occurred along the weld interface.
The formation of intermetallic compounds in the weld joints was investigated by X-ray diffraction, scanning electron microscopy
imaging, and elemental analysis techniques. Micro and nanoindentation characterization methods were used to evaluate the mechanical
properties at the interface, including the fracture toughness. The fracture toughness measurements by a Vickers indenter introduced
Palmqvist type cracks at all four corners of the indents and cube corner indenter resulted in the intermetallic chipping.
The fracture toughness (K
IC) calculation by both the micro and nanoindentation methods showed very low values, which is the primary reason for the brittle
failure of the dissimilar weld joints and concomitant low tensile strengths. 相似文献
6.
A modified hybrid ? equivalent circuit is developed for the transistor mixer. It is based on input-port measurements and simple theory. This equivalent circuit is valid for a wide range of emitter current and local-oscillator voltage, provided that the local oscillator and signal frequencies are small compared with the ft of the transistor. 相似文献
7.
S. Venkateswaran R. M. Mallya M. R. Seshadri 《International Journal of Cast Metals Research》2013,26(2):72-82
AbstractThe effect of trace elements, used for modification, on the cooling curves obtained during solidification, microstructure and mechanical properties of eutectic aluminium-silicon alloy was investigated. The results of this study indicate the following: 1 The addition of sodium or sodium plus strontium or antimony modifies the eutectic silicon while the addition of sulphur does not alter the microstructure. 2 Those elements which modify the eutectic-silicon, lower the eutectic solidification temperature, while those elements which do not bring about modification, do not alter the eutectic solidification temperature. 3 The addition of those elements which modify the eutectic aluminium-silicon alloy, viz., sodium or sodium plus strontium or antimony improves the UTS and percentage elongation. The addition of titanium to eutectic aluminium-silicon alloy containing these trace elements improves the UTS and percentage elongation to a further extent. Among the various trace elements added to eutectic aluminium-silicon alloy, the addition of sodium plus titanium improves the UTS and percentage elongation to the maximum extent. 相似文献
8.
Rheological properties of emulsions made out of avocado pulp and watermelon seed oils with whey protein concentrate were determined during different storage periods. The oils, as well as the emulsions behaved like non-Newtonian liquids, having shear-thinning characteristics. Both oils showed moderate shear-thinning characteristics as the flow behaviour indices were between 0.86 and 0.88. The shear-rate/shear-stress data could be adequately fitted (r = 0.997–0.999) to a common rheological equation, e.g. the power-law model. Avocado pulp oil was markedly more viscous than was watermelon seed oil which was also evident from the higher apparent viscosity and consistency index values. 相似文献
9.
10.
P. Y. Emelie J. D. Phillips B. Buller U. D. Venkateswaran 《Journal of Electronic Materials》2006,35(4):525-529
The electronic properties of semiconductors are highly dependent on carrier scattering mechanisms determined by crystalline
structure, band structure, and defects in the material. Experimental characteristics of lattice vibrational modes and free
carrier absorption in single-crystal ZnO samples obtained from different sources are presented in this work to provide a further
understanding of carrier scattering processes pertaining to electronic properties. Infrared absorption measurements indicate
strong absorption peaks due to a combination of optical and nonpolar phonon modes in the 9–13 μm spectral region. The Raman
spectra obtained for these samples similarly reveal the presence of these phonon modes. Infrared absorption measurements also
demonstrate free carrier absorption in the 3–9 μm spectral region for higher conductivity samples, where a λm dependence is observed with m=2.7–3, indicating both longitudinal optical phonon scattering and ionized impurity scattering.
From these results, we show that infrared absorption can be used as a routine nondestructive technique to determine the material
characteristics and quality of bulk ZnO. 相似文献