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新疆某碾压混凝土重力坝坝址所处地区冬季长且寒冷,春、秋二季短,夏季气温高且干燥少雨,多年平均气温2.7℃,年温差极大且蒸发强盛,对碾压混凝土施工非常不利。为了保证碾压混凝土坝的施工质量,必须对混凝土的施工全过程进行严格控制。通过对原材料、拌和系统、施工仓面的全面有效控制,最终混凝土施工质量全部达到设计及施工规范标准。 相似文献
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定子是发电机中产生电磁感应,进行机械能与电能转换的主要部件,定子线圈嵌入铁芯后用槽楔固定于槽中,绕组两端绑牢在端箍上,机组运行一段时间后偶尔出现个别槽楔松动现象,绝大部分槽楔松动、线圈整体下沉现象极为少见。主要介绍乌鲁瓦提水电厂2#机组定子线圈下沉现象的发现、原因分析、现场处理方法等,供参考。 相似文献
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Caijin Shi Xieraili Maimaitiyiming 《International Journal of Hydrogen Energy》2021,46(17):10247-10258
The development of efficient and durable bifunctional catalysts for oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) is desirable but remains a great challenge. Herein, a series of new three-dimensional (3D) nitrogen, phosphorus and sulfur doped porous graphene (NPS G) were fabricated by facile and cost-effective strategy, as efficient bifunctional electrocatalysts for direct methanol fuel cell. To obtain superior ORR and MOR bifunctional catalytic activities, we optimized the doping amount of nitrogen, phosphorus and sulfur in catalysts. The resulting metal-free NPS G2 catalyst had a long-term stability, desirable four electron pathway and excellent methanol poisoning tolerance. Moreover, NPS G2 exhibited higher onset potential compared to other metal-free NPS G, and close to commerical Pt/C catalyst current density under the same conditions. In addition, a series of NPS G used as good supports for Pt nanoparticles. Pt/NPS G2 catalyst displayed remarkable electrochemical performance, better cyclic stability and tolerance in methanol electrooxidation reaction. 相似文献
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The ability of the skin to be pressure‐sensitive has prompted scientists to develop materials and equipment to simulate this function. Recently, flexible and stretchable artificial electronic skin has received increasing attention with its unique ability to detect subtle pressure changes. Pressure sensing is one of the key functions of electronic skin devices. Here, a stretchy and highly sensitive pressure sensor is developed that used a polydimethylsiloxane (PDMS) film with leather composite layer as flexible part. These features enable the sensor to accurately detect a variety of human activities, such as small finger movements and bending, pulse and so on. The sensor is found to have a good sensing signal for temperature. This feature provides great promise for sensors to detect temperature. 相似文献
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分析乌鲁瓦提水电厂原调速器存在的问题,提出调速器更换的必要性,并对新型PCC可编程调速器的结构、原理及调速器在应用过程中过速的原因和处理方法进行了详细的介绍。 相似文献
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Flexible and wearable devices are important parts toward the realization of artificial intelligence and have an irreplaceable advantage over traditional rigid sensors. In this work, a film with double surface structure is prepared by using sandpaper and the leather with a rhombic structure as a mold, thereby obtaining a sandwich structure resistive type pressure sensor, which has high sensitivity (77.78 kPa?1, 24 Pa minimum detection) and wide detection range (0.024–230 kPa). The sensors have fast response time (30 ms) and high reliability over 5000 repetitive cycles. The humidity sensor is printed on the top layer of the sensor by using screen printing and inkjet printing technique, and the sandwich structure humidity and pressure sensor is obtained. The humidity sensors show the sensitivities of 0.137/%, 1.57/%, and 11.145/% in the relative humidity range from 25 to 55%, 55 to 70%, and 70 to 80%, respectively. Such sensors not only have excellent capabilities in pressure and humidity detection, but also avoid the complex process of multiple single‐function devices stacked on each other. The applications of sensors in monitoring artery pulse waves, detecting spatial pressure distribution, and sweat is demonstrated. 相似文献
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