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21.
Zhe Guo Qihua Zhu Shan Wu Changzheng Hu Laijun Liu Liang Fang 《Ceramics International》2018,44(7):7700-7708
Unfilled tungsten bronze ceramics with the nominal formula Ba4PrFe0.5Nb9.5O30 were synthesized via the standard solid-state sintering route, and the effects of oxygen vacancies on the dielectric and electrical properties were investigated in addition to the structure. Room-temperature X-ray diffraction showed that the N2-annealed sample had the largest cell volume. Low-temperature spectrum showed that N2 annealing rendered the dielectric constant and dielectric loss more frequency dispersive, whereas O2 annealing inhibited the frequency dispersion. The dc conductivity of all the samples originated from the electrons produced in the second ionization of oxygen vacancies and was most likely controlled by a mixed conduction mechanism of the electron and oxygen-vacancy ions. The N2-annealed sample has the highest dc conductivity owing to its high concentration of oxygen vacancies. The broadening of the Raman lines and the decrease of Raman intensity for the N2-annealed sample originated from a significant structural disorder. X-ray photoelectron spectra demonstrated that the increased oxygen vacancies caused by the change of valences of Fe and Pr ions contributed to the structural disorder. 相似文献
22.
Multimedia Tools and Applications - Understanding human emotions through facial expressions is key enabling technology for interactive robots. Most approaches of facial expression recognition are... 相似文献
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Multimedia Tools and Applications - To achieve low-cost and fast multi-channel surface projection geometric correction, the quadratic quasi-uniform B-spline surface is used to reconstruct the... 相似文献
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Xue Ren Tiantian Tang Xinfang Xie Wenjun Wang Xuanming Tang Charles S. Brennan Jie Zhang Zhidong Wang 《International Journal of Food Science & Technology》2020,55(11):3475-3483
The effect of a traditional dish sour and spicy potato silk preparation and cooking process on B vitamins, phenolic profiles and antioxidant activities was investigated. Results showed that cutting of potato caused an increase in VB1, VB2, nicotinic acid, nicotinamide, VB7 and VB9. Soaking decreased the content of B vitamins and vitamin C. Blanching and rinsing caused the contents of B vitamins and vitamin C decrease compared to the control. The content of VB1, VB5 and VB6 after rinsing increased compared to soaking and blanching processes. However, VB1, nicotinamide, VB5, VB6 and VC decreased sharply after the stir-frying process. The content of VB1, nicotinic acid, nicotinamide, VB7 and VC retained the most after five steps compared to the control. In addition, there was no difference in VB9 contents among different cooking processes compared to the control. Superoxide dismutase (SOD) exhibited a reduction rate of 95.32% and peroxidase (POD) 97.13% after the stir-frying process. 相似文献
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文章针对乌鲁木齐机场多普勒天气雷达(以下简称ADWR)2009~2019年发生的故障次数、故障分布以及备件更换情况,逐年统计故障率,深入分析了ADWR系统性能,总结出运行维护中的经验,就如何更好地提高雷达业务运行指标提出建议,以提高ADWR雷达的维护、维修能力,建立有针对性的备件管理,为科学的业务运行管理提供依据。 相似文献
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Solar photocatalytic hydrogen production from water has been regarded as an ideal way addressing world energy and environmental crises. The technology has long relied on the development of an efficient photocatalyst. In addition to its photocatalytic performance, the large-scale production of certain photocatalyst from the viewpoint of particle application remains a challenge yet has received insufficient focus. Herein, we report an efficient and practical batch preparation system based upon hydrothermal method to the scalable production of chalcogenide nanoparticle photocatalyst. Taking the synthesis of Cd0.5Zn0.5S (CZS) twinned photocatalyst as an example, the outcome of CZS photocatalyst could reach ~0.8 kg in this batched synthesis, which is about 390 times of the lab-scale production in mass amount. It was found that the twinned structure and visible-light absorption property were well maintained. Although further measurements toward the photocatalytic activity indicate slight decrement on solar H2 generation compared to the lab-scale synthesized CZS photocatalyst, a high quantum efficiency of about 40.5% at 425 nm remained. The photocatalytic reaction could also stably proceed for 200 h without notable decay of H2-evolution rate. This work thus provides a powerful means for facile scaling up the chalcogenide nanoparticle photocatalyst at the kilogram level with both high quality and good reproducibility. 相似文献
29.
应力测试是起重机安全评估中必须进行的一项检测。目前在安全评估工作中常采用应变电测法来采集起重机工作过程中的应力时程数据,由于该方法只能采集到结构由于载荷变化产生的应力,而无法采集到结构因自重产生的应力,导致应力测试无法获取结构的完整应力。利用起重机金属结构自重应力在总应力中占有的权重,分析其对应力测试实验结果的影响大小,试验结果表明在危险截面自重应力大小占总应力大小可达60%,此时不考虑自重应力进行结构安全性的判定是不全面的。可考虑利用仿真技术获取自重应力[1,2],从而使得安全评估应力测试实验结论更加准确。 相似文献
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