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Polyimides containing siloxane moieties are used in some advanced applications. For example, these polymers can be employed as separation membranes in the form of self-standing, thin films. These products are formed by components of different polarities that have the tendency, at least partly, to separate in the final materials, with an impact on their final, bulk, and/or surface properties. The aim of this work is to study the dependence of the composition of the polyimide, poly(imide-siloxane) (PIS) and copolymeric PIS self-standing films differing in thickness on their properties. The important finding is that there is a rather large difference observed in the water contact angle on the film side oriented toward the air atmosphere during film preparation and that oriented toward a hydrophobic Teflon surface. Nevertheless, the gas transport properties of carbon dioxide and methane for these membranes are more influenced by the membrane composition than by the surface properties.  相似文献   
53.
    
Fluoroethylene carbonate (FEC) as an electrolyte additive can considerably improve the cycling performance of silicon (Si) electrodes in Li‐ion batteries. However, the fundamental mechanism for how FEC contributes to solid electrolyte interphase (SEI) morphological changes and chemical composition is not well understood. Here, scanning transmission electron microscopy coupled with electron energy loss spectroscopy gives a comprehensive insight as to how FEC affects the SEI evolution in terms of composition and morphology throughout electrochemical cycling. In the first lithiation cycle, the electrode cycled in ethylene carbonate (EC): diethylene carbonate (DEC) forms a porous uneven SEI composed of mostly Li2CO3. However, the electrode cycled in EC/DEC/FEC is covered in a dense and uniform SEI containing mostly LiF. Interestingly, the intrinsic oxide layer (Li x SiO y ) is not observed at the interface of electrode cycled in EC/DEC/FEC after 1 cycle. This is consistent with fluoride anion formation from the reduction of FEC, which leads to the chemical attack of any silicon‐oxide surface passivation layer. Furthermore, surface sensitive helium ion microscopy and X‐ray photoelectron spectroscopy techniques give further insights to the SEI composition and morphology in both electrodes cycled with different electrolytes.  相似文献   
54.
The use of liquid films flow offers solutions for the problems associated with the microgravity applications. The thermal entry length of laminar wavy falling films was experimentally determined under full gravity conditions by means of infrared thermography. A dependence of the entry length on the Reynolds, Prandtl, and Kapitza number as well as the ratio Pr0/PrW between the Prandtl numbers at inflow and wall temperatures was found.  相似文献   
55.
We have investigated two new modes of operation been in T-10 limiter tokamak experiments with a novel rotary feeder of lithium dust. Quasi steady-state mode I and pulse mode II of dust delivery were realized in both OH and OH + ECRH disruption free plasmas at the lithium flow rate up to 2 × 1021 atoms/s. A higher flow rate in mode II with injection rate of ~5 × 1021 atoms/s caused a series of minor disruptions, which was completed by discharge termination after the major disruption. The observed decreases of bolometer and Dβ signals, with increase of the electron density during the lithium dust injection, reveal the effects of the first wall conditioning. The lithium technology may provide inherent safety pathway for major disruption mitigation in a tokamak reactor, which requires demonstration in contemporary tokamak experiments.  相似文献   
56.
Cardiovascular diseases are complex pathologies that include alterations of various cell functions at the levels of intact tissue, single cells and subcellular signalling compartments. Conventional techniques to study these processes are extremely divergent and rely on a combination of individual methods, which usually provide spatially and temporally limited information on single parameters of interest. This review describes scanning ion conductance microscopy (SICM) as a novel versatile technique capable of simultaneously reporting various structural and functional parameters at nanometre resolution in living cardiovascular cells at the level of the whole tissue, single cells and at the subcellular level, to investigate the mechanisms of cardiovascular disease. SICM is a multimodal imaging technology that allows concurrent and dynamic analysis of membrane morphology and various functional parameters (cell volume, membrane potentials, cellular contraction, single ion-channel currents and some parameters of intracellular signalling) in intact living cardiovascular cells and tissues with nanometre resolution at different levels of organization (tissue, cellular and subcellular levels). Using this technique, we showed that at the tissue level, cell orientation in the inner and outer aortic arch distinguishes atheroprone and atheroprotected regions. At the cellular level, heart failure leads to a pronounced loss of T-tubules in cardiac myocytes accompanied by a reduction in Z-groove ratio. We also demonstrated the capability of SICM to measure the entire cell volume as an index of cellular hypertrophy. This method can be further combined with fluorescence to simultaneously measure cardiomyocyte contraction and intracellular calcium transients or to map subcellular localization of membrane receptors coupled to cyclic adenosine monophosphate production. The SICM pipette can be used for patch-clamp recordings of membrane potential and single channel currents. In conclusion, SICM provides a highly informative multimodal imaging platform for functional analysis of the mechanisms of cardiovascular diseases, which should facilitate identification of novel therapeutic strategies.  相似文献   
57.
All ceramic anode supported half cells of technically relevant scale were fabricated in this study, using a novel strontium titanate anode material. The use of this material would be highly advantageous in solid oxide fuel cells due to its redox tolerance and resistance to coking and sulphur poisoning. Successful fabrication was possible through aqueous tape casting of both anode support and electrolyte layers and subsequent lamination. Screen printing of electrolyte layers onto green anode tapes was also attempted but resulted in cracked electrolyte layers upon firing. Microstructural, electrical and mechanical properties of anode supports and half cells will be discussed. The use of two different commercial titanate powders with nominal identical, but in reality different stoichiometries, strongly affect electrical and mechanical properties. Careful consideration of such variations between powder suppliers, and batches of the same supplier, is critical for the successful implementation of ceramic anode supported solid oxide fuel cells.  相似文献   
58.
The main aim of the investigation was to quantify the influence of production-related cross-lines on static mechanical properties (tensile, flexural and shear) of an oxide-oxide CMC as a comparison between specimens with cross-lines and specimens without cross-lines in tested regions. Investigated material was a weak-matrix oxide-oxide CMC (WHIPOX?) made of Nextel? 610 fibers (3000 denier) and alumina matrix with a special winding pattern. Mechanical tests at room temperature revealed that cross-lines were local weak regions in a wound component. Spatial separation of the cross-line within the composite (2?mm shift from layer to layer) did not improve the negative influence of the cross-lines on mechanical properties. Fractographic investigations revealed that cross-lines acted as a trigger of material failure.  相似文献   
59.
Wang  Shuqin  Chen  Yongyong  Cen  Yigang  Zhang  Linna  Wang  Hengyou  Voronin  Viacheslav 《Applied Intelligence》2022,52(13):14651-14664
Applied Intelligence - Multi-view subspace clustering has attracted significant attention due to the popularity of multi-view datasets. The effectiveness of the existing multi-view clustering...  相似文献   
60.
In recent years development of active materials for negative electrodes has been of great interest. Special attention has been focused on the active materials possessing higher reversible capacity than that of conventional graphite. In the present work the electrochemical performance of some carbon/silicon-based materials has been analyzed. For this purpose various silicon-based composites were prepared using such carbon materials as graphite, hard carbon and graphitized carbon black. An analysis of charging-discharging processes at electrodes based on different carbon materials has shown that graphite modified with silicon is the most promising anode material. It has also been revealed that the irreversible capacity mainly depends on the content of Si. An optimum content of Si has been determined with taking into account that high irreversible capacity is not suitable for practical application in lithium-ion batteries. This content falls within the range of 8-10 wt%.The reversible capacity of graphite modified with 8 wt% carbon-coated Si was as high as 604 mAh g−1. The irreversible capacity loss with this material was as low as 8.1%. The small irreversible capacity of the material allowed developing full lithium-ion rechargeable cells in the 2016 coin cell configuration. Lithium-ion batteries based on graphite modified with silicon show gravimetric and volumetric specific energy densities which are higher by approximately 20% than those for a lithium-ion battery based on natural graphite.  相似文献   
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