全文获取类型
收费全文 | 219篇 |
免费 | 3篇 |
专业分类
电工技术 | 36篇 |
综合类 | 1篇 |
化学工业 | 45篇 |
金属工艺 | 5篇 |
机械仪表 | 2篇 |
建筑科学 | 9篇 |
能源动力 | 5篇 |
轻工业 | 11篇 |
水利工程 | 4篇 |
无线电 | 40篇 |
一般工业技术 | 36篇 |
冶金工业 | 10篇 |
原子能技术 | 2篇 |
自动化技术 | 16篇 |
出版年
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 18篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 4篇 |
2007年 | 10篇 |
2006年 | 4篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 8篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 6篇 |
1970年 | 2篇 |
1967年 | 2篇 |
1965年 | 2篇 |
1964年 | 4篇 |
1963年 | 3篇 |
1957年 | 2篇 |
1946年 | 2篇 |
排序方式: 共有222条查询结果,搜索用时 859 毫秒
41.
Gabriela Buda Lucian Dascalescu Adrian Samuila 《Particulate Science and Technology》2013,31(2):162-167
The control of the triboelectrification factors is the key for a successful application of electrostatic separation to the recycling of mixed plastics waste. This article focuses on the influence of material moisture on the tribocharging process of three granular materials: polyamide (PA), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). Different values of moisture content were obtained by immersing the material in water or drying it in a laboratory oven. Afterward, the granular material was tribocharged on the tray of a vibratory feeder and the accumulated charge was measured by an electrometer. The maximum charge/mass ratio was obtained for the three plastic materials at different values of moisture content: 0.27% for PA, 0.12% for PET 0.1% for PVC. Series of 5 consecutive tribocharging experiments performed on the same sample, show that the first contributes with the greater amount of granules charge while the other four only slightly increment this value. The graphical representation of the evolution of the charge/mass ratio versus number of tribocharging experiment conducts to the conclusion that: i) the charge of the granules tends to saturate; ii) it is useless to excessively increase the duration of the tribocharging process. 相似文献
42.
43.
Dascalescu L. Mihalcioiu A. Tilmatine A. Mihailescu M. Iuga A. Samuila A. 《Industry Applications Magazine, IEEE》2004,10(6):19-25
Optimization of electrostatic separation processes demands the control of a multitude of factors, including the characteristics of the granular mixtures to be sorted, the feed rate, the configuration of the electrode system, the applied high-voltage and the environmental conditions. The Taguchi's experimental designs presented in this article clearly prove that the linear-interaction models of the electrostatic separation processes can reflect the effects of the main factors in a manner that is satisfactory to most case of the practical interest. The Taguchi's experimental designs are based on special matrices called orthogonal arrays. 相似文献
44.
High-resolution solid-state 13C n.m.r. has been used to study the amorphous phase of PVF2/PMMA blends. The decrease of the carbon magnetization as a function of the contact duration in a cross-polarization sequence was analysed in terms of the local composition heterogeneities occurring during PVF2 crystallization. The influence of the composition and thermal history of the samples is discussed. 相似文献
45.
We present an assessment of the methods used to construct maps for a new solar radiation atlas for Europe. For this atlas, station data and satellite-derived data are used in an interpolation/merging process to derive maps of the long-term monthly global radiation that cover an area ranging from 30° W to 70° E and from 25° to 75° N. Our focus is on the discussion of the accuracy of the method applied: a co-kriging technique. Special emphasis is put on a discussion as to whether the use of satellite-derived radiation maps with a low spatial resolution brings benefits. 相似文献
46.
Toussaint D. Robert Lucien D. Laude Viktor M. Geskin Roberto Lazzaroni Rachel Gouttebaron 《Thin solid films》2003,440(1-2):268-277
Pressed disks of TiO2 powder particles (≈1 μm in size) have been irradiated with a pulsed KrF (248 nm) excimer laser source at fluences between 0.1 and 1 J cm−2. Surface films (1.5–2 μm thick) have been studied by Raman microprobe spectroscopy and atomic force microscopy (AFM). The Raman study reveals a three-layer structure for the irradiated anatase powders. A dark layer of reduced oxide is sandwiched between a top coating of molten/resolidified rutile and an underlying defective, slightly oxygen-deficient mixed-phase of rutile and anatase. AFM measurements indicate that a smooth surface layer coexisting with the initial rough grain morphology gradually appears with increasing fluence. At low fluence, anatase is reduced in a dark film and further transformed into rutile. At intermediate fluence, a shiny coating of resolidified stoichiometric rutile forms on the dark film. It gets thicker as the fluence increases while darkening of the sublayer intensifies up to a maximum of approximately 700 mJ cm−2. At high fluence, however, melting and re-oxidation (and eventually ablation) prevail over reduction; the whole layer turns into a greyish crust of mostly resolidified rutile in non-ablated regions. A physico-chemical mechanism is proposed to explain the in-depth distribution of the various components as a function of fluence. 相似文献
47.
A preozonation study has been done at the potable water treatment plant of Moulle, in the North of France. The water is particularly rich in organic matter, with also algal blooms every, year, so the coagulan t treatmen t dose which is necessary for an optimal treatment, is very high. Previous laboratory tests have shown the importance of a preoxidation step, before the coagulation–flocculation–sedimentation industrial treatment line. It is also well known that flotation permits a significant reduction of coagulant dose. In addition, prechlorination of a water containing a large amount of organic matter induces the formation of a relatively high concentration of haloforms. 相似文献
48.
Lucien Goldschmidt 《History of Photography》2013,37(2):183-184
Abstract Until about 1910, pictorial and professional photographers produced strikingly different work and interacted very little with one another. Most pictorialists strove to create atmospheric, mysterious and emotionally charged images that often resembled other works of art. They hand-crafted photographs that were sofdy focused, low in tonalities and printed in such exotic processes as gum-bichromate, platinum or photogravure. Motivated by pure self-expression, pictorialists made every effort to prove that their pictures were fine art, looking down on utilitarian photographs as crass and soulless. 相似文献
49.
Yanfeng Gao Pascale Magaud Lucien Baldas Christine Lafforgue Micheline Abbas Stéphane Colin 《Microfluidics and nanofluidics》2017,21(10):154
Controlling the transport of particles in flowing suspensions at microscale is of interest in numerous contexts such as the development of miniaturized and point-of-care analytical devices (in bioengineering, for foodborne illnesses detection, etc.) and polymer engineering. In square microchannels, neutrally buoyant spherical particles are known to migrate across the flow streamlines and concentrate at specific equilibrium positions located at the channel centerline at low flow inertia and near the four walls along their symmetry planes at moderate Reynolds numbers. Under specific flow and geometrical conditions, the spherical particles are also found to line up in the flow direction and form evenly spaced trains. In order to statistically explore the dynamics of train formation and their dependence on the physical parameters of the suspension flow (particle-to-channel size ratio, Reynolds number and solid volume fraction), experiments have been conducted based on in situ visualizations of the flowing particles by optical microscopy. The trains form only once particles have reached their equilibrium positions (following lateral migration). The percentage of particles in trains and the interparticle distance in a train have been extracted and analyzed. The percentage of particles organized in trains increases with the particle Reynolds number up to a threshold value which depends on the concentration and then decreases for higher values. The average distance between the surfaces of consecutive particles in a train decreases as the particle Reynolds number increases and is independent of the particles size and concentration, if the concentration remains below a threshold value related to the degree of confinement of the suspension flow. 相似文献
50.
Rezzouga M Tilmatine A Gouri R Medles K Dascalescu L 《Frontiers of Electrical and Electronic Engineering in China》2007,2(2):139-143
Many studies, both experimental and numerical, were devoted to the electric current of corona discharge and some mathematical
models were proposed to express it. As it depends on several parameters, it is difficult to find a theoretical or an experimental
formula, which considers all the factors. So we opted for the methodology of experimental designs, also called Tagushi’s methodology,
which represents a powerful tool generally employed when the process has many factors to consider. The objective of this paper
is to model current using this experimental methodology. The factors considered were geometrical factors (interelectrode interval,
surface of the grounded plane electrode, curvature radius of the point electrode), climatic factors (temperature and relative
humidity), and applied high voltage. Results of experiments made it possible to obtain mathematical models and to analyse
the interactions between all factors. 相似文献