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31.
Position sensorless vector control has been applied to compressor drive systems using an IPMSM to realize higher efficiency. In this paper, reduction control of cyclic speed change is proposed in order to achieve improved performance, including low vibration and low acoustic noise. Designing a speed estimator by using an adaptive observer with a wide frequency band, the fundamental frequency component of the cyclic speed change is calculated by a bandpass filter. The proposed compensation method recognizing the fundamental component can reduce the cyclic speed change to an acceptable level. The principle of the compensation method is presented along with experimental results. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 75–84, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20765 相似文献
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33.
We have successfully synthesized novel polyurethanes where PU1 contains a [3]rotaxane that consists of N-3,5-di-tert-butylbenzyl-N-3-hydroxypropylammonium hexafluorophosphate (AOH1) and N,N′-Dimethyl-N,N′-bis(dibenzo-24-crown-8)-terephthalamide (BisC) as well as PU2 contains a [2]rotaxane that consists of AOH1 and dibenzo-24-crown-8 ether. Diphenylmethanediisocyanate (MDI), 1,4-butanediol (BD) and poly(ε-caprolactone)diol (PCL) were used as an isocyanate, chain expander, and soft segment, respectively. A polyurethane without any rotaxane structures (PU0) were also prepared as a reference polymer. The existence of the rotaxanes in the polyurethanes was confirmed by 1H NMR spectroscopy and TGA measurement. ATR-FT-IR spectral measurement revealed that the rotaxanes disturb the formation of hydrogen bonding between the polyurethane chains. From the DSC result, the rotaxanes retard the recrystallization of the PCL unit whereas no influence on the glass transition temperatures of the polyurethanes was observed. The retarding effect appeared remarkably with PU1. These thermal behaviors of the polyurethanes were also supported by viscoelastic measurement. In tensile test, the tensile strength and break of strain of PU1 were larger than those of PU2. 相似文献
34.
Soluble carbon nanotubes and their applications 总被引:1,自引:0,他引:1
Carbon nanotubes (CNTs) have been the forefront of nanoscience and nanotechnology due to their unique electrical and mechanical properties and specific functions. However, due to their poor solubility in solvents, the applications using the materials have been limited. Therefore, strategic approaches toward the solubilization of CNTs are important in wide fields including chemistry, physics, biochemistry, biology, pharmaceuticals, and medical sciences. In this article, we summarize: (i) the strategic approaches toward the solubilization of CNTs using chemical and physical modifications, (ii) nanocomposites of CNTs and biological molecules including DNA, (iii) formation of CNTs with topological structures, (iv) separation of metallic and semiconducting nanotubes, (v) the preparations of films and fibers of CNTs and hybrid materials of CNTs and organic and inorganic molecules. 相似文献
35.
Maruta K Watanabe H Nishimoto T Kubota M Chaen H Fukuda S Kurimoto M Tsujisaka Y 《Journal of Bioscience and Bioengineering》2006,101(5):385-390
We investigated the acceptor specificity of a thermostable trehalose phosphorylase from Thermoanaerobacter brockii ATCC 35047 (TbTP) was examined using beta-D-glucose-1-phosphate (beta-G1P) as a glucosyl donor and oligosaccharides as the acceptor. Oligosaccharides with a reducing-end glucose residue as the C-6 substituent (e.g., isomaltose, gentiobiose, melibiose, isomaltotriose, and isopanose) were found to be successful acceptors. The transfer products of isomaltose, gentiobiose, and melibiose were isolated and characterized as 6-O-alpha-D-glucopyranosyl trehalose (alpha-GlcTre), 6-O-beta-D-glucopyranosyl trehalose (beta-GlcTre), and 6-O-alpha-D-galactopyranosyl trehalose (alpha-GalTre), respectively. To produce alpha-GalTre, a novel nonreducing trisaccharide, the reaction conditions of alpha-GalTre were examined using trehalose as a glucosyl donor. As a result, the yield of alpha-GalTre reached 40.5%. 相似文献
36.
Yoshihide Fujisaki Hiroto Sato Tatsuya Takei Toshihiro Yamamoto Hideo Fujikake Shizuo Tokito Taiichiro Kurita 《Journal of the Society for Information Display》2008,16(12):1251-1257
Abstract— An organic thin‐film‐transistor (OTFT) driven color flexible ferroelectric‐liquid‐crystal (FLC) display with 160 × 120 pixels and a resolution of 50 ppi has been developed. The flexible FLC was fabricated on a pentacene‐OTFT array using printing and lamination techniques. To drive the display at a fast driving speed, an OTFT was developed with a short channel length having a large current output. The fabricated OTFT array with a channel length of 5 μm exhibits a carrier mobility of 0.3 cm2/V‐sec and an ON/OFF ratio of over 107 at a low drain voltage of ?6 V. A field‐sequential‐color system with a flexible backlight unit was also developed and used to drive the display. Color moving images were successively shown on the 5‐in. display using an active‐matrix driving technique of the OTFT. 相似文献
37.
Mitsuru Ohnishi Shoichi Yoshihara Masato Sakurai Yuichi Miura Masamichi Ishikawa Hiroto Kobayashi Takeyoshi Takenouchi Jun Kawai Katsuya Honda Masaaki Matsumoto 《Microgravity science and technology》2005,16(1-4):306-310
In order to conduct a detailed investigation of the piston effect, the peculiar heat transportation phenomenon in critical fluids, an ultra-sensitive high-speed density measurement system was developed using a very thin heater, a sensitive interferometer and a large-capacity high-speed data acquisition system. As the first step of the investigation, an experiment was conducted to measure the velocity of sound in CO2 near its critical point. Short heat pulses suppressing the disturbance of natural convection were applied to a small cell filled with almost-critical CO2 fluid and were detected by the measurement system. Because the pulses propagated through the cell at the velocity of sound and were reflected several times between the cell walls, the velocity could be precisely determined by measuring the time intervals between successive reflections. The resulting velocity profile versus temperature showed good agreement with theoretical prediction and numerical simulations. This result validated the density measurement system, and it is considered that the measurement system will be a very effective tool for further studies on critical phenomena with the aid of numerical simulation. 相似文献
38.
Kimitoshi Sato Mrinalini Mishra Hiroto Hirano Chunfeng Hu Yoshio Sakka 《Journal of the American Ceramic Society》2014,97(5):1407-1412
Easy sinterable Ti3SiC2 powder was synthesized from a powder mixture with a molar ratio of 1.0 Ti, 0.3 Al, 1.2 Si, and 2.0 TiC by heating at 1200°C in the flowing Ar. Here, the Al powder acts as a deoxidation agent and provides a liquid phase for the reaction. The powder compacts subjected to pressureless sintering at 1300°C in Ar had a relative density up to 99%. The results of chemical analysis and the measured lattice constant suggest that the Al–Si liquid phase was formed at approximately 1200°C and that liquid‐phase sintering was promoted by the 0.1 molar ratio of Al and the 0.2 molar ratio of Si remaining in excess. The three‐point bending strength, fracture toughness, and electrical resistivity of the sintered samples were 380 MPa, 4.1 MPa m1/2, and 0.34μΩm, respectively. 相似文献
39.
The impact of a two-dimensional elastic disk with a wall is numerically studied. It is clarified that the coefficient of restitution (COR) decreases with the impact velocity. The result is not consistent with the recent quasi-static theory of inelastic collisions even for very slow impact. This suggests that the elastic model cannot be used in the quasi-static limit. A new quasi-static theory of impacts is proposed, in which the effect of thermal diffusion is dominant. The abrupt decrease of COR has been found due to the plastic deformation of the disk, which is assisted by the initial internal motion. 相似文献
40.
Yamamoto T Mukai K Maruta K Watanabe H Yamashita H Nishimoto T Kubota M Chaen H Fukuda S 《Journal of Bioscience and Bioengineering》2005,100(3):343-346
The kojibiose phosphorylase (KP) gene and trehalose phosphorylase (TP) gene from Thermoanaerobacter brockii ATCC35047 were intracellularly hyper-expressed under the control of the Bacillus amyloliquefaciens alpha-amylase promoter in Bacillus subtilis. The production yields were estimated to be 2.1 g of KP and 4.9 g of TP per liter of medium. Selaginose, non-reducing trisaccharide, was synthesized from trehalose utilizing the recombinant KP and TP from B. subtilis. Selaginose was not hydrolyzed by salivary amylase, artificial gastric juice, pancreatic amylase, or small intestinal enzymes. 相似文献