全文获取类型
收费全文 | 63篇 |
免费 | 2篇 |
专业分类
化学工业 | 22篇 |
机械仪表 | 7篇 |
建筑科学 | 3篇 |
能源动力 | 1篇 |
轻工业 | 6篇 |
水利工程 | 1篇 |
无线电 | 8篇 |
一般工业技术 | 6篇 |
冶金工业 | 2篇 |
原子能技术 | 1篇 |
自动化技术 | 8篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 7篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2004年 | 1篇 |
2003年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1994年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1968年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有65条查询结果,搜索用时 78 毫秒
41.
42.
Liang Zhixiu Song Liang Elnabawy Ahmed O. Marinkovic Nebojsa Mavrikakis Manos Adzic Radoslav R. 《Topics in Catalysis》2020,63(7-8):742-749
Topics in Catalysis - The direct formic acid fuel cell holds great promise as a next generation portable power source. Here we report an experimental study on Pt and Pd monolayer (Pt* and Pd*) atop... 相似文献
43.
Radoslav Selecký Daniela Šmogrovičová Pavol Sulo 《Journal of the Institute of Brewing》2008,114(2):97-101
A collection of Saccharomyces cerevisiae strains deficient in the tricarboxylic acid cycle enzymes activities has been examined for the production of beer with reduced ethanol content. Strains deficient in fumarase and α‐ketoglutarate dehydrogenase encoded by the genes FUM1 (0.48%), KGD1 (0.42%) and KGD2 (0.48%) made non‐alcoholic beers with an alcohol content lower than 0.5% (v/v). The rest of the yeast mutants also gave rise to low‐alcoholic beers but with a slightly elevated ethanol concentration (mostly in the range of 0.57‐0.84% and 1.64% for the lip5 mutant). Low ethanol content was compensated by the considerable increase of organic acids (citrate succinate, fumarate, and malate). In addition, some of the mutants released high levels of lactic acid (144 fum1), 622 (kgd1) and 495 (kgd2) mg/L). Lactic acid protects beers against contamination and masks an unacceptable worty off‐flavour. 相似文献
44.
Thomas E. Wood Zhongshu Tan Alison K. Schmoeckel David O’Neill Radoslav Atanasoski 《Journal of power sources》2008
The cost of platinum is one of the major obstacles in the commercialization of proton exchange membrane fuel cells. Non-precious metal catalysts (NPMC) as an inexpensive substitute for platinum have been viewed as the only long-term solution to the problem. In this paper, we introduce new precursors used to synthesize NPMC active sites through metal-assisted polymerization of nitrogen-containing, aromatic molecules. Results of electrochemical characterization, which was performed in a real fuel cell environment, with emphasis on the activity of the catalyst are presented. Catalytic activity among the highest in the NPMC area was obtained when using 4-nitroaniline as a precursor. 相似文献
45.
Radoslav Tomovic Aleksandar Miltenovic 《International Journal of Mechanical Sciences》2010,52(9):1176-1185
Rolling element bearings appear in nearly 90% of all rotating machinery. Their dynamic performance is often the limiting factor in the performance of the machines that use them. The specific construction of a bearing has a decisive influence on its dynamic behaviour. The paper defines a new vibration model of a rigid rotor supported by rolling element bearings. By application of the defined model, the parametric analysis of the influence of internal radial clearance value and number of rolling elements influence on rigid rotor vibrations in unloaded rolling element bearing was performed. The defined vibration model and parametric analysis were verified experimentally. The results of experimental analysis are also presented in this paper. 相似文献
46.
YongMan Choi Kurian A. Kuttiyiel Joselito P. Labis Kotaro Sasaki Gu-Gon Park Tae-Hyun Yang Radoslav R. Adzic 《Topics in Catalysis》2013,56(12):1059-1064
Designing novel cathode materials for a proton exchange membrane fuel cell with high activity for the oxygen reduction reaction, low Pt loading, and enhanced long-term stability is imperative for its sustainability. To date, Pt monolayer based electrocatalysts deposited on a metallic core substrate have shown promising possibilities. In this study, we synthesized bimetallic IrCu nanoparticles and used them as a core for Pt monolayer electrocatalysts. It was found that the de-alloyed IrCu nanoparticle surfaces increased both the mass and specific activities of the resulting Pt monolayer catalyst. In addition, we demonstrated that Pt monolayer electrocatalysts with a de-alloyed IrCu core have a better stability than those using a non-dealloyed core based on a 5,000 potential cycling test. These data describe a new simple synthesis of a high-performance catalyst suitable for practical applications. 相似文献
47.
Wei-Ping Zhou Meng Li Christopher Koenigsmann Chao Ma Stanislaus S. Wong Radoslav R. Adzic 《Electrochimica acta》2011,(27):9824
The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection–absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO2-to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail. 相似文献
48.
Ivan Šimkovic Igor Šurina Radoslav Mikulášik Anna Orságová Aleš Ház Clemens Schwarzinger 《应用聚合物科学杂志》2013,127(1):508-515
The properties of lignocellulose materials from the trunk and bark of trees, and from agricultural sources were investigated by thermogravimetry (TG) and pyrolysis–gas chromatography/mass spectrometry (Py‐GC/MS). The goal was to learn which of the phytomass sources is the most accessible to dehydration and aldol reactions, and in this way could be considered suitable for composite preparation by the thermal pressing treatment. The bagasse second differential thermal analysis peak in air is at the highest temperature acceptable for intermolecular dehydration/crosslinking, and therefore we consider bagasse to be the most suitable candidate for composite preparation. From the TG results in air at 250°C, it follows that willow wood and bagasse are the most thermally resistant sources. The data obtained by Py‐GC/MS analysis showed glycolaldehyde and acetic acid as dominant markers related to adhesion properties via aldol condensation. The detected sum amount of glyceraldehyde and acetic acid decreases in the order: beech wood > bagasse > acacia wood > sugar beet pulp, whereas the remaining species produced much less of it. By comparing results run at above conditions with composite preparation using the pressing thermal treatment at a temperature of 150°C and pressures up to 800 kPa, the suggested evaluation was examined for application on sugar beet residue. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
49.
The influence of vanadium on fracture toughness and abrasion resistance in high chromium white cast irons 总被引:2,自引:0,他引:2
The influence of vanadium on wear resistance under low-stress conditions and on the dynamic fracture toughness of high chromium white cast iron was examined in both the ascast condition and after heat treatment at 500 °C. A vanadium content varying from 0.12 to 4.73% was added to a basic Fe-C-Cr alloy containing 2.9 or 19% Cr. By increasing the content of vanadium in the alloy, the structure became finer, i.e. the spacing between austenite dendrite arms and the size of massive M7C3 carbides was reduced. The distance between carbide particles was also reduced, while the volume fraction of eutectic M7C3 and V6C5 carbides increased. The morphology of eutectic colonies also changed. In addition, the amount of very fine M23C6 carbide particles precipitated in austenite and the degree of martensitic transformation depended on the content of vanadium in the alloy. Because this strong carbide-forming element changed the microstructure characteristics of high chromium white iron, it was expected to influence wear resistance and fracture toughness. By adding 1.19% vanadium, toughness was expected to improve by approximately 20% and wear resistance by 10%. The higher fracture toughness was attributed to strain-induced strengthening during fracture, and thereby an additional increment of energy, since very fine secondary carbide particles were present in a mainly austenitic matrix. An Fe-C-Cr-V alloy containing 3.28% V showed the highest abrasion resistance, 27% higher than a basic Fe-C-Cr alloy. A higher carbide phase volume fraction, a finer and more uniform structure, a smaller distance between M7C3 carbide particles and a change in the morphology of eutectic colonies were primarily responsible for improving wear resistance. 相似文献
50.
Selected trace transition metal ions have been determined in an FIA/HPLC hyphenated system using on-line preconcentration on cellulose functionalised sorbent Cellex P. For HPLC separation ion-pair chromatography was employed with spectrophotometric detection at 510 nm using post-column derivatisation with PAR. Favourable kinetic conditions of sorption and elution as well as optimisation of hyphenated system allowed to obtain detection limits at sub-microgL(-1) level at 25 min preconcentration time. The developed method was employed for determination of Co(II), Ni(II), Cd(II) and Mn(II) in river water with reasonable agreement of obtained results with electrothermal AAS determination. 相似文献