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61.
Microencapsule was incorporated into an interpenetrating polymer network and applied over steel surface. A scratch was made on the coated surface and its self healing ability was studied using scanning vibrating electrode technique (SVET) and electrochemical impedance spectroscopy (EIS). Results of SVET studies show that the current density increases in the initial stage. After 24 h, the current density decreases, which indicating the formation of passive polymer film due to the diffusion of core polymer present in the microcapsules through the holidays. Increase in the resistance (107 Ω/cm2) of the self healing coating was observed after 24 h in EIS studies confirming the formation of the passive film. The results of the studies are discussed in this article. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
62.
Selvaraj Ranjith Priyan Govindan Suresh Kumar Srinivasan Surendhiran Mohd. Shkir 《International Journal of Applied Ceramic Technology》2023,20(5):2807-2816
Mesoporous silica nanoparticles with distinct characteristics like particle size, tunable pores, and high surface area have received much interest for environmental remediation, energy conversion, and biological applications. In this work, we synthesized spherical silica nanoparticles with tunable particle size and mesoporous properties using a low-cost silica source (rice husk) and polyethylene glycol (PEG) via microwave-assisted sol–gel synthesis. The formation of an amorphous silica structure was found using XRD and FTIR analysis. FESEM analysis showed that altering the PEG concentration from .01 to .005 M produced spherical silica nanoparticles with 100–500 nm in size. Nitrogen adsorption–desorption demonstrated that silica nanoparticles obtained with .005, .007, and .01 M of PEG had unique pore sizes and distributions, with specific surface areas of 51.475, 62.367, and 84.251 m2/g, respectively. These results might be due to PEG molecules’ capping effect, which acts as a soft template to regulate particle size, pore size, and dispersion by interacting with sodium silicate precursor. Hence, this approach can be a facile and cost-effective method to prepare mesoporous silica nanoparticles with controllable nanoscale characteristics for suitable applications. 相似文献
63.
Ulagaraj Selvaraj Alamanda V. Prasadarao Sridhar Komarneni Rustum Roy 《Journal of the American Ceramic Society》1992,75(5):1167-1170
Thin films of titania have been prepared by spin coating on fused silica, Si(100), and rutile(110), starting with a sol–gel process. The alkoxide solution was chelated with diisopropanolamine, and the resulting precursor solution was hydrolyzed prior to coating. Oriented rutile films were obtained on fused silica and Si(100), while epitaxially oriented film was formed on rutile (110). X-ray diffraction results indicated that the as-deposited films transformed to rutile via anatase with increasing temperature. The phase transformation temperature was found to be dependent on the substrate, and it was in general higher on the substrates than that observed for the gel powder. Microstructural studies revealed that these films consisted of finely dispersed grains of 0.05 to 0.15 μm in size. 相似文献
64.
65.
Epoxy-polyamide coatings are used to protect metallic substrates in corrosive atmosphere. Thermal stability of the coating can be improved by the addition of inorganic cross-linking agent. Epoxy resin is incorporated with small percentage of silicone resin and cured with two types of hardeners such as polyamide and butyl titanate. The physical properties, heat resistance properties and electrochemical impedance behaviour of these coatings on steel in 0.5 M NaCl solution have been studied. The result implies that the heat resistant character of the titanate-cured coating is increased from 260 to 370 °C. The impedance study has shown that the coating resistance exerted by both the systems is in the range of 105 Ω cm2 after 6 days of immersion in 0.5 M NaCl. FTIR and Raman spectroscopy analysis confirm the presence of titanate linkage in the cured polymer coating. Thermal stability data indicate that the epoxy silicone resin cured with titanate hardener possesses higher thermal stability than that cured by polyamide hardener. 相似文献
66.
Y. Oumi M. Yamadaya T. Kanougi M. Kubo A. Stirling R. Vetrivel E. Broclawik A. Miyamoto 《Catalysis Letters》1997,45(1-2):21-26
We report here the result of a computer- assisted study of metallosilicates by applying molecular dynamics (MD) and quantum
chemical (QC) methods. MD calculations are used to study the local relaxation in the T12 site of the ZSM-5 structure, when
Si is substituted by different metals such as Ti4+, Al3+, Ga3+, and Fe3+. QC calculations by density functional theory have been performed on the cluster models generated from the structure obtained
by MD calculations. The calculation indicates that the net charge on a MO4 (where M = Ti, Al, Ga, and Fe) group and the molecular electrostatic potential values are good parameters to assess the acidic
properties of metallosilicates, as shown by their correlations to the reported experimental acidity.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
67.
Cheon Seok OhHero Kim Selvaraj RengarajYounghun Kim 《Microporous and mesoporous materials》2012,147(1):1-4
A sensing electrode for the detection of heavy metal ions in aqueous solution selectively measured the concentrations of target materials on its functionalized surface, which has affinity to target metal ions. Target ions were adsorbed simultaneously on the functionalized electrode during the sensing process. Therefore, to understand this, experiments on the amperometric response and isotherms with an initial concentration of Hg2+ were tested. Detection current was dependent on the concentration of Hg2+, and the equilibrium concentration of Hg2+ adsorbed to the electrode showed a Langmuirian shape. Correlation between the detection current and removal capacity for Hg2+ revealed that it is possible to estimate the adsorbed concentration on the electrode during the sensing step. Although the macroporous gold electrode prepared herein showed relatively low adsorption performance compared to conventional adsorbents, when we prepare nanoporous gold electrodes with a uniform nanopore structure and large surface area, in situ detection and simultaneously removal of metal ions by nanoporous gold electrode will be possible. 相似文献
68.
R. Gajapathy K. Velusamy P. Selvaraj P. Chellapandi S.C. Chetal T. Sundararajan 《Nuclear Engineering and Design》2008,238(7):1577-1591
Intermediate heat exchanger (IHX) in a pool-type liquid metal cooled fast breeder reactor is an important heat exchanging component as it forms an intermediate boundary between the radioactive primary sodium in the pool and the non-radioactive secondary sodium in the steam generator (SG). The thermal loads during steady state and transient conditions impose thermal stresses on the heat exchanger tubes and on the shells which hold the tube bundle. Estimation of these thermal loads and achieving uniform temperature distribution in the tubes and shells by having uniform flow distributions are the major tasks of thermal hydraulic investigations of IHX. Through multi-dimensional thermal hydraulic investigations performed using commercially available computer codes such as PHOENICS, the flow and temperature distributions in the tubes and shells and in its secondary sodium inlet and outlet headers are obtained with and with out provisions of flow distribution devices. The effectiveness of these devices in achieving acceptably uniform flow and temperature distributions has been assessed and thermal loads on the tubes and shells for thermo mechanical analysis of the IHX have been defined. The predictions of the computational studies have been validated against simulated experiments. 相似文献
69.
70.
Delay‐dependent fault‐tolerant controller for time‐delay systems with randomly occurring uncertainties 下载免费PDF全文
Rathinasamy Sakthivel Ramalingam Sakthivel Palanisamy Selvaraj Hamid Reza Karimi 《国际强度与非线性控制杂志
》2017,27(18):5044-5060
》2017,27(18):5044-5060
This paper addresses the passivity‐based control problem for a class of time‐varying delay systems subject to nonlinear actuator faults and randomly occurring uncertainties via fault‐tolerant controller. More precisely, the uncertainties are described in terms of stochastic variables, which satisfies Bernoulli distribution, and the existence of actuator faults are assumed not only linear but also nonlinear, which is a more general one. The main objective of this paper is to design a state feedback‐reliable controller such that the resulting closed‐loop time‐delay system is stochastically stable under a prescribed mixed and passivity performance level γ>0 in the presence of all admissible uncertainties and actuator faults. Based on Lyapunov stability method and some integral inequality techniques, a new set of sufficient conditions is obtained in terms of linear matrix inequality (LMI) constraints to ensure the asymptotic stability of the considered system. Moreover, the control design parameters can be computed by solving a set of LMI constraints. Finally, two examples including a quarter‐car model are provided to show the efficiency and usefulness of the proposed control scheme. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献