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排序方式: 共有1490条查询结果,搜索用时 156 毫秒
41.
XIN Ying GONG WeiZhi & ZHANG JingYin Innopower Superconductor Cable Co. Ltd. E.Rongchang Rd. Longsheng Industrial Park Beijing Economic & Technological Development Area Beijing China 《中国科学:信息科学(英文版)》2010,(4)
A superconductor has zero resistance at the superconducting state. This unique property creates many exceptional phenomena, of which some are known and the others are not. Our experiments with multilayer high temperature superconductor (HTS) cable samples revealed a new phenomenon that alternating current had a tendency to flow in the inner and outer layers of the cables. We attribute the cause of this phenomenon to the electromagnetic interaction in an infinite electrical conductivity medium and term it su... 相似文献
42.
There is a significant push to increase the output power of thermoelectric generators (TEGs) in order to make them more competitive energy harvesters. The thermal coupling of TEGs has a major impact on the effective temperature gradient across the generator and therefore the power output achieved. The application of micro fluidic heat transfer systems (μHTS) can significantly reduce the thermal contact resistance and thus enhance the TEG's performance. This paper reports on the characterization and optimization of a μTEG integrated with a two layer μHTS. The main advantage of the presented system is the combination of very low heat transfer resistances with small pumping powers in a compact volume. The influence of the most relevant system parameters, i.e. microchannel width, applied flow rate and the μTEG thickness on the system's net output performance are investigated. The dimensions of the μHTS/μTEG system can be optimized for specific temperature application ranges, and the maximum net power can be tracked by adjusting the heat transfer resistance during operation. A system net output power of 126 mW/cm2 was achieved with a module ZT of 0.1 at a fluid flow rate of 0.07 l/min and an applied temperature difference of 95K.It was concluded that for systems with good thermal coupling, the thermoelectric material optimization should focus more on the power factor than on the figure of merit ZT itself, since the influence of the thermal resistance of the TE material is negligible. 相似文献
43.
Ceramic green tape extrusion for laminated object manufacturing 总被引:2,自引:0,他引:2
Al2O3 and SiC green tapes with 0.2 mm thickness used for LOM (laminated object manufacturing) were prepared from a 75 wt.% ceramic suspension in a LDPE based organic vehicle followed by extrusion. Rheological characterization of the alumina and SiC suspensions were studied. TG-DTA analysis was carried out in air and microstructures were examined by SEM. 相似文献
44.
The durability of digital audio tape is a function of the elastic and plastic properties of the magnetic layer and substrate. In this work a micro-indentation method has been used to estimate these properties. The loading part of the compliance curve (load against indentor penetration) is analysed to obtain magnetic layer hardness. The unloading part is used to determine the reduced elastic modulus. Indentations at various depths have been recorded and an extrapolation technique used to predict layer properties. Rate dependence of the magnetic layer has been studied through constant loading rate tests. Results are presented isochronally, to indicate any viscous elastic–plastic non-linearities. 相似文献
45.
A. F. Ryzhkov L. Zhargalkhuu Nadir Saman M. Sharif A. D. Makhaev 《Journal of Engineering Physics and Thermophysics》2009,82(1):21-28
To estimate the thermohydraulic efficiency of different types of swirlers of heat exchange in pipes, we have generalized the
experimental data, which has made it possible to determine the optimal range of Reynolds numbers and the optimal geometric
sizes of swirlers.
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 1, pp. 23–30, January–February, 2009. 相似文献
46.
A. I. Y. Tok F. Y. C. Boey M. K. A. Khor 《Journal of Materials Engineering and Performance》1999,8(4):469-472
The production of ceramic green tapes is integral to the production of multilayer ceramic packages and capacitors. This article
presents a batch type process for producing alumina ceramic green tape down to 150 μm thickness. The process parameters relevant
to the precise control of the thickness of an aluminabased ceramic tape have been investigated using a float glass tape caster.
Results indicate that the cast tape thickness was dependent on the blade gap until it reached a limiting value. This limiting
thickness in turn was dependent on the casting speed, with a higher speed producing thinner tapes. Optimal casting was shown
to exist when the blade gap was set at or beyond the limiting value, with the casting speed the controlling factor for the
final thickness. 相似文献
47.
《Journal of Adhesion Science and Technology》2013,27(1):69-86
The effects of 248 nm KrF excimer laser irradiation on a pressure-sensitive adhesive tape bonded to a glass substrate were investigated as a possible method to evaluate the quality of adhesion, as well as the directionality induced during manufacture. The model pressure-sensitive tape consisted of biaxially-oriented polypropylene (PP) tape coated with a hot-melt rubber resin. Analysis of the front-shot experiments, which were performed by irradiation through the PP backing, allowed correlation between the excimer laser irradiation-induced detachment and the peel adhesion strength. For this purpose, peel tests were performed before and after laser shots. The directionality induced during manufacture resulted in a more ablated area in the strength direction than in the transverse direction when the bonded tapes were irradiated with an elliptically-shaped laser beam above the ablation threshold. A correlation was found between the detachment bubbles created by irradiation below the ablation threshold and their respective peel adhesion values, which allows us to evaluate the quality of adhesion for pressure-sensitive tapes. Thus, a method to evaluate the quality of adhesion using an excimer laser is proposed based on the findings of this work. 相似文献
48.
The shear stress–strain behaviour of two low-modulus structural adhesives has been measured using the butt-torsion test. The Nadai correction for non-linear shear behaviour is explained as it is necessary to understand how this correction can be applied to butt joints. The results for one adhesive were accurately used to predict the strength of a lap joint, and it was shown that the strength of such a joint can approach that of a conventional, modern, structural epoxy. Structural adhesives are usually reckoned to be those with a high strength (50 MPa and upwards) and (these days), a strain to failure of at least 10% in tension, and which usually have a tensile modulus of 2 GPa or so. However, adhesives which are significantly less stiff, less strong, but much more ductile are entering the ‘structural’ arena. In order to evaluate their effectiveness and use in design, it is necessary to be able to measure accurately their stress–strain behaviour. Two such materials are 3M 9245 Structural Bonding Tape (SBT) and 3M 7838 B/A. 相似文献
49.
该文通过分析胶带输送机跑偏的原因,制定了相应的措施,分析托辊运转问题,提出了解决方法,收到了良好的效果。 相似文献
50.