Yang Ju
,
Yasushi Ohno
,
Hitoshi Soyama
,
Masumi Saka
材料科学技术（英文）
A method for electrical characterization of doped silicon in a contactless fashion using high-frequency electromagnetic waves was presented. A focusing sensor was used to focus a 110 GHz microwave on the surface of a silicon wafer. The amplitude and phase of the reflection coefficient of the microwave signal were measured, by which electrical conductivity of the wafer was determined quantitatively, independent of the permittivity and thickness of the wafer. The conductivity obtained by this method agrees well with that measured by the conventional four-point-probe method.
关键词:
Conductivity
,
null
,
null
,
null
Subhra Gantayat
,
Gyanaranjan Prusty
,
Dibya Ranjan Rout
,
Sarat K Swain
新型炭材料
doi:10.1016/S1872-5805(15)60200-1
采用溶液技术制备出膨胀石墨增强环氧树脂复合材料. 对石墨进行化学改性以提高与环氧树脂的相容性. 采用XRD﹑FE-SEM和HR-TEM对环氧树脂/膨胀石墨复合材料进行表征. 与环氧树脂相比,添加质量分数9%膨胀石墨后,该复合材料的热分解温度从340 ℃升高至480 ℃,抗张应力提高30%,导电率由10-15增加至10-5数量级. 热学﹑力学和电学性能的显著提高,主要归因于膨胀石墨纳米片在环氧树脂基体中的良好分散性,从而可用于广泛的应用领域.
关键词:
膨胀石墨
,
扫描电镜
,
透射电镜
,
导电率
陈昊
,
王欣欣
,
李杰飞
,
曹新鑫
,
何小芳
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2016.05.001
介绍了近年来石墨烯改性聚合物和功能化石墨烯改性聚合物纳米复合材料的研究现状.其中,在石墨烯改性聚合物方面,主要论述了石墨烯改性聚乙烯(PE)、聚丙烯(PP)、聚苯乙烯(PS)以及聚苯胺(PA-NI)纳米复合材料的制备方法和性能改善;在功能化石墨烯改性聚合物方面,主要论述了二苯基甲烷二异氰酸酯(MDI)、十八烷基胺(ODA)、氯化铝(AlCl3)等对石墨烯的修饰以及改性后的石墨烯对聚合物的影响.最后,对石墨烯/聚合物纳米复合材料的潜在应用和发展前景做出了展望.
关键词:
石墨烯
,
复合材料
,
改性
,
力学性能
,
导电性能
Z.El-Gohary
,
A.Abdel-Aal
,
A.Elshafie
材料科学技术（英文）
Several thin films of Te10Ge10Se77Sb3 chalcogenide glass of different thicknesses (250nm to 400nm) were prepared by thermal evaporation under vacuum of 133 ×10-6 Pa(10-6torr). X- ray diffraction analysis showed the amorphicity of the prepared films which become partially crystalline by annealing. Transmittance and reflectance measurements in the spectral range of 200nm to 2500nm have been carried out at normal incidence. The analysis of the absorption coefficient data showed the existence of indirect transition for the photon energy E in the range 1-3eV and direct transition for E>3eV. From the determination of the optical constants (n, k), the dispersion of the refractive index has anomalous behaviour in the region of the fundamental absorption edge, and followed by the single- effective oscillator approach.The investigated optical parameters such as the optical energy gap Eopt, the high frequency dielectric constant eoo ,the oscillator position lo, and the oscillator strength So, were significantly affected by the film thickness. The characteristic energy gap obtained from the conductivity measurements is nearly half the value of that obtained from the optical data as in the case of thickness 400nm. The activation energy is 0.65 eV and the indirect optical gap is 1.32eV.
关键词:
Chalcogenide glasses
,
null
,
null
