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排序方式: 共有416条查询结果,搜索用时 15 毫秒
1.
等离子体氧化nc-Si/SiO_2多层膜的蓝光发射 总被引:1,自引:0,他引:1
报道了在等离子体增强化学气相沉积 (PECVD)系统中用交替淀积 a-Si对其进行原位等离子体氧化的方法制备了 a-Si∶H/ Si O2 多层膜。随着 a-Si∶H子层的厚度从 3 .8nm减小到 1 .5 nm,a-Si∶H/ Si O2 多层膜的光吸收边和光致发光 (PL )出现了蓝移。在晶化的 a-Si∶ H/ Si O2 多层膜中不仅观察到室温下的红光带 (80 0nm)的发光峰 ,而且还观察到蓝光发射 (4 2 5 nm) ,结合 Raman,TEM和 PL测试 ,对其原因作了简单的分析 相似文献
2.
One of the most promising applications of encapsulated living cells is their use as protected transplanted tissue into the human body. A suitable system for the protection of living cells is the use of nano‐ or microcapsules of polyelectrolytes. These shells can be deposited easily on top of the cells by means of a layer‐by‐layer technique. An interesting feature of the capsules is the possibility to control their properties on a nanometre level, tuning their wall texture via the preparation conditions. Here we introduce a model system to test the protection ability of polyelectrolyte capsules. Common bakery yeast cells were encapsulated. They were coated with a fluorescently labelled shell at conditions known to guarantee cell survival, and the cell interior was stained with DAPI. The protozoan Paramecium primaurelia was incubated with this double‐stained living yeast and visualized by means of two‐photon excitation fluorescence microscopy. Cross‐sections of the dye‐stained material as well as autofluorescence of the fixed protozoan allowed us to follow the digestion of the coated yeast with time. Our investigation reveals that capsules prepared under these deposition conditions are permeable to lysosomal enzymes, leading to degradation of the yeast inside the intact capsules. Our preliminary results indicate the suitability of the introduced model as a test system of this permeability. 相似文献
3.
调制波长对Cu/Ni金属多层膜力学性能的影响 总被引:2,自引:0,他引:2
用电沉积法在低碳钢基体上制备了具有不同调制波长(一个调制波长等于单层Cu膜与单层Ni膜厚度之和)的Cu/Ni金属多层膜,研究了多层膜硬度与其中单层膜厚度之间的关系。结果表明,当膜厚在亚微米范围内时,Cu/Ni多层膜的屈服强度(为硬度值的1/3)与单层膜厚之间符合基于位错塞积模型的Hall-Pctch(H-P)关系式;而当单层膜厚小于100nm时,屈服强度与膜厚的关系偏离了H-P线性关系。基于程开甲等人位错稳定性理论首次对金属多层膜变形行为偏离Hall-Petch关系的现象作了定量解释。 相似文献
4.
5.
B. Holzapfel M. Leghissa P. Bauer G. Kreiselmeyer M. Kraus S. Bouffard L. Schultz G. Saemann-Ischenko 《Journal of Superconductivity》1994,7(1):205-207
Epitaxial YBa2Cu3O7–
thin films (YBCO) and YBa2Cu3O7–
/PrBa2Cu3O7–
multilayers (Y/Pr) were irradiated with high-energy heavy ions (770 Mev208Pb) under various directions relative to thec-axis. The irradiation resulted in columnar defects tilted by from thec-axis. The angular dependence of their pinning activity was studied by measuring the anisotropy of the critical current density. TheJ
c
(B, T,) behavior of the irradiated YBCO thin films showed an additional peak, which exceeds the intrinsic pinning peak, exactly at the irradiation direction. The Y/Pr multilayers, however, showed an isotropicT
c
-enhancement by a factor of 5, without any additional structure in theJ
c(B, T,) curve. 相似文献
6.
Enric Menéndez Hiwa Modarresi Claire Petermann Josep Nogués Neus Domingo Haoliang Liu Brian J. Kirby Amir Syed Mohd Zahir Salhi Earl Babcock Stefan Mattauch Chris Van Haesendonck André Vantomme Kristiaan Temst 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(11)
The combination of lithography and ion implantation is demonstrated to be a suitable method to prepare lateral multilayers. A laterally, compositionally, and magnetically modulated microscale pattern consisting of alternating Co (1.6 µm wide) and Co‐CoO (2.4 µm wide) lines has been obtained by oxygen ion implantation into a lithographically masked Au‐sandwiched Co thin film. Magnetoresistance along the lines (i.e., current and applied magnetic field are parallel to the lines) reveals an effective positive giant magnetoresistance (GMR) behavior at room temperature. Conversely, anisotropic magnetoresistance and GMR contributions are distinguished at low temperature (i.e., 10 K) since the O‐implanted areas become exchange coupled. This planar GMR is principally ascribed to the spatial modulation of coercivity in a spring‐magnet‐type configuration, which results in 180° Néel extrinsic domain walls at the Co/Co‐CoO interfaces. The versatility, in terms of pattern size, morphology, and composition adjustment, of this method offers a unique route to fabricate planar systems for, among others, spintronic research and applications. 相似文献
7.
Interface reaction (IR) is a frequently observed phenomenon in the study of advanced thin film materials. It is very important to study the reaction conditions at which IR happens and then to suppress or make use of it, the necessary conditions, including both thermodynamical and dynamical conditions of IR were discussed in detail. IRs in various systems, including oxide/silicon, oxide/metal, metal/metal, metal/semiconductor and semiconductor/semiconductor, were reviewed. Methods to suppress and make use of IR were also introduced. 相似文献
8.
9.
《Intermetallics》2017
Carbon-doped Mn3Ga thin films were grown on Si/SiO2 substrates using rf magnetron sputtering technique. The tetragonal D022–type crystalline structure of ferrimagnetic Mn3Ga is preserved on the Mn3GaCx films upon carbon concentrations up to x = 0.5, whereas higher concentrations lead to the formation of the antiperovskite Mn3GaC phase. Geometry optimization calculations using the density functional theory were performed on a 2 × 2 × 2 Mn3GaC0.25 supercell with C in different positions in order to find that the most stable position for the C is interstitial octahedral site. Magnetic M(H) loops show that saturation magnetization Ms of Mn3GaC0.25 is enhanced to 200 kAm−1 (from Ms = 90 kAm−1 for undoped films). The increase of the C concentration leads to a reduction of the Curie temperature from 770 K to ∼420 K at the same time that the lattice cell suffers an expansion. The enhancement of Ms is explained in terms of a 90° ferromagnetic superexchange Mn-C-Mn interaction. 相似文献
10.
Seung Koo Lee Myung Shin Han Ching‐Hsuan Tung 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(21):3315-3320
A long‐lasting particle‐based fluorescent label is designed for extended cell imaging studies. This onion‐like nanoprobe is constructed through layer‐by‐layer fabrication technology. The nanoprobes are assembled with multiple layers of optically quenched polyelectrolytes, the fluorescence signal of which can be released later by intracellular proteolysis. Upon incubation with cells, the assembled nanoprobes are taken up efficiently. The tight packing and layered assembly of the quenched polyelectrolytes slow subsequent intracellular degradation, and then result in a prolonged intracellular fluorescence signal for up to 3 weeks with no noticeable toxicity. 相似文献