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121.
采用大电流交流脉冲对非晶Fe78B13Si9合金进行了去应力退火。初步探讨了电脉冲加热对加热速率和该合金内应力释放、退火脆化以及最终软磁性影响的基本规律。结果表明:电脉冲加热可以得到远高于常规退火的加热速率,选择合适工艺参数可使非晶合金内应力释放90%,软磁性(H_c和B_s)达常规退火后的95%以上,与此同时使合金的延性(断裂应变ε_f)维持在0.9以上,从而有望实现非晶合金磁性与延性的合理配合。 相似文献
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Abstract This study deals with the modeling of air pollution in apartments from laboratory measurements of source strengths, using formaldehyde and Total Volatile Organic Compounds (TVOCs) as model pollutants. The sources in two test apartments were grouped into two: building-related sources and occupant-related sources. The measured source strengths and ventilation rates were used for the prediction of concentrations expected in the apartments. These predictions were compared to measurements in the apartment over 12 months. The conclusions were that the model predictions based on emission rates measured in the laboratory can be used to predict the long-term concentration of the two model pollutants in the apartments. Considering the measured differences in ventilation between the apartments, an occupant emission rate of between 0.2 and 0.3 mg/h/kg body weight could be estimated. Based on previous suggested limits of acceptable exposures of humans to VOCs, an acceptable average emission rate of VOCs from building materials in general was estimated to be about 30 (μ/m2/h. The modeling showed that during the first 200 days, building materials dominated the emissions. After this, sources relating to the occupants dominated. On average about half of the VOC pollution originated from the building materials. 相似文献
124.
电容器介质吸收电流的测量和表征 总被引:6,自引:0,他引:6
在外电场作用下,电容器介质的吸收电流和漏电电流混杂而难以分开,但外电场除去后吸收电流对电容器放电总电荷所贡献的百分比具有确定值,吸收电流的释放遵从自由弛豫规律。可用响应时间r’表征。实验给出了一些常见介质的吸收电流表征参数。 相似文献
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126.
Dielectric properties andI–V characteristics of solution-gas interface-formed PbS thin-film capacitors (Al/PbS/Al) of various thicknesses have been studied
in the frequency range 10-106 Hz at various temperatures (300–443 K). Current-voltage (I–V) characteristics show space-charge-limited conduction. Dielectric constant (ε) increases with increasing film thickness and temperature and decreases with increase of frequency. The loss factor (tanδ) peaks observed in tanδ vs frequency and tanδ vs temperature reveal relaxation effect from dipolar orientation. These maxima shift to higher-temperature region with increasing
frequency. The large increase in capacitance (C) and dielectric constant (ε) towards low-frequency (f) region indicates the possibility of an interfacial polarization mechanism in this region. 相似文献
127.
本文介绍了PROTEL元件符号图形库和点阵汉字库的结构,以及怎样将点阵汉字库转换到PROTEL元件符号图形库的方法。从而提出一种在利用PROTEL设计电路原理图时,加入汉字标注的途经。 相似文献
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129.
Fei Xu Zhisong Xiao Guoan Cheng Zhongzhen Yi Tonghe Zhang Lanlan Gu Xun Wang 《Thin solid films》2002,410(1-2):94-100
In this work, high concentration erbium doping in silicon-rich SiO2 thin films is demonstrated. Si plus Er dual-implanted thermal SiO2 thin films on Si substrates have been fabricated by using a new method, the metal vapor vacuum arc ion source implantation with relatively low ion energy, strong flux and very high dose. X-Ray photoelectron spectroscopy measurement shows that very high Er concentrations on the surfaces of the samples, corresponding to 10 at.% or the doping level of 1021 atoms cm−3, are achieved. This value is much higher than that obtained by using other fabrication methods such as the high-energy ion implantation and molecular beam epitaxy. Reflective high-energy electron diffraction, atomic force microscopy and cross-section high-resolution transmission electron microscopy observations show that the excess Si atoms in SiO2 matrix accumulate to form Si clusters and then crystallize gradually into Si nanoparticles embedded in SiO2 films during dual-ion implantation followed by rapid thermal annealing. Er segregation and precipitates are not formed. Photoluminescence at the wavelength of 1.54 μm exhibits very weak temperature dependence due to the introduction of Si nanocrystals into the SiO2 matrix. The 1.54-μm light emission signals from annealed samples decrease by less than a factor of 2 when the measuring temperature increases from 77 K to room temperature. 相似文献
130.