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41.
依据红外反射式光电探纬的组成和工作原理,对有梭织机光电探纬系统进行了改进。将反光装置(膜)固定在梭芯上,减少了反光装置的数量,无需改动梭子和纬管,系统探纬准确,减少了换梭时纡脚回丝。 相似文献
42.
纤维水镁石阻燃瓦楞原纸的研制 总被引:1,自引:0,他引:1
介绍了阻燃瓦楞原纸的制备过程,对以不同配比纤维水镁石为添加剂的阻燃体系进行了研究,结果表明,纤维水镁石加入量在30%~120%时均能达到阻燃效果,在90%时综合效果最佳。对今后的研究重点给出了建议,并预测了纤维水镁石阻燃剂的发展前景。 相似文献
43.
从退火态原位TiCp/Fe复合材料的切削力和切屑形状方面分析了其切削性能。研究结果表明其切削力及切削力的波动范围都小于铸态45钢,其切削性能比45钢好。TiCp/Fe复合材料的切屑为C形屑、长紧卷屑和发条状卷屑,在机加工中,产生这几种切屑是比较理想的。从切屑方面看,TiCp/Fe复合材料的切削性能较好。 相似文献
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46.
Experiments were performed to investigate the heat transfer characteristics of a row of three premixed, laminar, butane/air flame jets impinging on a water-cooled flat plate. The between-jet interference was found to reduce the heat transfer rate in the jet-to-jet interacting zone due to the depressed combustion. The interference became stronger when the jet-to-jet spacing and/or the nozzle-to-plate distance were/was small. The positive pressure existed in the between-jet interacting zone caused the asymmetric flame and heat transfer distribution of the side jet. The meeting point of the spreading wall jets of the central and the side jets did not occur at the midpoint of the neighboring jets, but at a location shifted slightly outwards. The maximum local heat flux and the maximum area-averaged heat flux occurred at a moderate nozzle-to-plate distance of 5d with a moderate jet-to-jet spacing of 5d. The lowest area-averaged heat flux was produced when both the jet-to-jet spacing and the nozzle-to-plate distance were small. Comparing with a single jet under the same experimental conditions, the heat transfer rates in both the stagnation point and the maximum heat transfer point were shown to be enhanced in a row of three-jet-impingement system. The present study provided detailed information on the heat transfer characteristics of a row of three in-line impinging flame jets, which had rarely been reported in previous study. 相似文献
47.
This paper presents the current understanding of the flame retardant mechanism of Casico?. The study includes the flame retardant effect of each individual component: ethylene–acrylate copolymer, chalk and silicone elastomer, as well as the formation of an intumescent structure during heating. The flame retardant properties were investigated by cone calorimetry and oxygen index tests. To obtain insight into the flame retardant mechanism, heat treatment under different conditions has also been performed. The results indicate that the flame retardant mechanism of Casico is complex and is related to a number of reactions, e.g. ester pyrolysis of acrylate groups, formation of carbon dioxide by reaction between carboxylic acid and chalk, ionomer formation and formation of an intumescent structure stabilized by a protecting char. Special emphasis is given to the formation of the intumescent structure and its molecular structure as evaluated from 13C MAS‐NMR and 29Si MAS‐NMR, ESCA and XRD analysis. After treatment at 500°C the intumescent structure consists mainly of silicon oxides and calcium carbonate and after treatment at 1000°C the intumescent structure consists of calcium silicate, calcium oxide and calcium hydroxide. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
48.
Experimental results of a low-power roadheader driving a gallery with different types of rock at the face 总被引:1,自引:0,他引:1
J. Torao lvarez M. Menndez lvarez R. Rodríguez Díez 《Tunnelling and Underground Space Technology incorporating Trenchless Technology Research》2003,18(4):395-404
In this paper, the experimental results of a 45-kW and 15-t roadheader excavating a gallery with two different types of rock at the face using two different cutting heads are shown. It is proved that the roadheader works properly with both cutting heads. In comparison with other results in the literature, the principal parameters, i.e. specific energy, cutting rate and tool wear, are at a level that can be considered satisfactory taking into account the low power of the roadheader. On the other hand, the influence of the number of picks, which is the main difference between the two cutting heads, on the operational parameters is shown. 相似文献
49.
Atilla Bilgin 《国际能源研究杂志》2002,26(11):987-1000
Flame front surface area and enflamed volume (the volume enclosed with flame front) is theoretically analysed for a spark‐ignition engine, having cylindrical disc‐shaped combustion chamber with two spark plugs located axisymmetrically on cylinder head, between cylinder axis and cylinder wall. Spherical flame front assumption is used. A computer code is developed based on purely geometric consideration of the flame development process in combustion chamber, and is used to investigate the effects of variations of spark plugs' locations on geometric features of the flame front. A comparison has also been made with a spark‐ignition engine having one spark plug at the same location. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
50.
介绍了一种新型双族流平焰烧嘴的设计思路、结构参数及工业试验结果。其结构特点是每个部件都易装易卸,其煤气旋流器的位置可根据煤气压力变化进行调节,无需稳焰器就可保证煤气压力在较大范围波动时,都可形成稳定的平展火焰。 相似文献