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51.
Jiabao Cen Hao Jin Demiao Wang 《Journal of Materials Science: Materials in Electronics》2012,23(1):290-294
Metallization of positive temperature coefficient (PTC) thermistors deposited by direct current magnetron sputtering has been
investigated. Two kinds of multilayer thin films, namely Ti/NiCu/Ag and Al/NiCu/Ag, are proposed as electrode materials. Conventional
NiCr/Ag thin film serves as reference electrode in the experiment. Experimental results show that the newly proposed electrodes
exhibit good performance including low ohmic contact, firm adhesion, fine solderability and stability. The surface resistances
at room temperature of Ti/NiCu/Ag and Al/NiCu/Ag PTC range from 4.3 to 6.2 Ω, and they change little in moisture condition.
The average tensile strength is 6.3 Mpa, which provides firm adhesion between electrode and substrate. At solderability test,
the new electrodes can withstand the soakage of lead-free solder at 350 °C for 5 s and the properties remain stable after
high temperature treatment. 相似文献
52.
53.
Yi Xiang Ruikun Wang Junhong Wu Junhu Zhou Kefa Cen 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(24):3687-3693
In this study, oilfield wastewater (OWW) was used to prepare coal–oilfield wastewater–slurry (COWS), and the apparent viscosity, solid concentration, and rheological curve were studied. Compared with original coal–water–slurry (CWS), the maximum solid concentration of COWS increased, and the viscosity decreased; therefore, the slurrying ability of the coal slurry was improved with the use of OWW. However, although the oil in OWW promoted the slurrying ability of the coal slurry, its effectiveness was insufficient, and a chemical additive was still needed to obtain a coal slurry with enhanced slurrying ability. Both COWS and CWS exhibited shear-thinning behavior, and the rheological index value of COWS was lower, which indicated that pseudoplasticity of COWS was more obvious, and OWW improved the rheological properties of coal slurry. 相似文献
54.
配电变压器零序电流治理优化方法及装置 总被引:1,自引:0,他引:1
目前,在配电网采用的三相四线制中,针对三相不对称负荷运行导致零序电流长期偏高,造成变压器损耗并影响变压器的寿命,且现有全容性无功补偿装置易造成严重过补偿危害,本文提出了一套零序电流治理的全容性无功补偿优化算法及装置。主要通过实时计算三相负荷所需无功补偿量,利用优化算法以全电容方式对相间与相对地间电容器组进行动态投切,进而通过有功转移及无功补偿方式实施零序电流的抑制。挂网运行结果表明,该装置能有效防止严重过补偿危害,并能有效抑制零序电流的增长,提高功率因数以及降低配电变压器损耗;同时采用先进的GPRS无线通信和监控软件实时互动,为负荷的状态调整提供了参考信息,达到了节能减排的效果。 相似文献
55.
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57.
人工神经网络方法在优化动力配煤中的应用研究 总被引:10,自引:1,他引:10
对神经网络BP算法的一些改进作了大量的数值试验研究,并组合了部分改进方法用于动力配煤问题中状态预测过程的建模,最后把神经网络方法纳入到非线性混合离散变量优化设计方法(MDOD法)中,对杭州配煤场 动力配煤过程作了应用介绍。 相似文献
58.
59.
一种基于P2P点组技术的流媒体协作计算 总被引:4,自引:0,他引:4
分析了流媒体技术的现状和问题,讨论了在P2P环境下的流媒体多点分布式调度技术和调度性能分析,以及多点调度下的带宽分配算法,最后给出了一个基于P2P点组的流媒体协作调度模型。 相似文献
60.
Qing Yao Le Zhang Pan Gao Bingheng Sun Cen Shao Yuelong Ma Tianyuan Zhou Ming Li Hao Chen Yun Wang 《Journal of the American Ceramic Society》2020,103(6):3513-3527
Large and nondeforming Nd: YAG ceramic prepared by wet forming is of great importance as gain medium to obtain high-power solid-state lasers. However, it is difficult to achieve high-quality laser ceramics due to insufficiency of the in-depth understanding of transformation mechanism of gels viscoelasticity and effective control means during drying process. In this work, the rheological behaviors, viscoelastic characteristics, and mechanical strengths in classical acrylamide (AM) and novel Isobam (PIBM) gelcastings were systematically compared to explore the suitable route for the large-sized 2% Nd: YAG transparent ceramics with high aspect ratio (>10). AM system exhibited a higher complex viscosity (1.82 × 105 Pa s), a shorter gel time (92.9 seconds), and a higher flexural strength (about 24.46 MPa) than PIBM system, and especially its ability to quickly gel was beneficial to the homogeneity of green body. In addition, the order of drying rates of wet gels in four drying media was observed as follows: 55℃ hot air> ethanol> solid desiccant> PEG-11000 and the moisture diffusion coefficients were calculated and simulated to offer the deep consideration of drying kinetics. The “ethanol + 55℃ hot air” was regarded as an effective composite drying method to eliminate defect and to achieve φ8 mm × 160 mm Nd: YAG ceramic with the in-line transmittance of 83% @1064 nm. Therefore, not only the cognition of gel process, but also the defects control strategy is proposed. More importantly, this work greatly promotes the application of wet forming and laser ceramics in high-power lasers. 相似文献