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91.
Young Chul Choi Milan Pophristic Ho-Young Cha Boris Peres Michael G. Spencer Lester F. Eastman 《Electron Devices, IEEE Transactions on》2006,53(12):2926-2931
An Fe-doped GaN buffer layer was employed in the growth of AlGaN/GaN high-electron mobility transistors (HEMTs) on Si substrates. In order to investigate the effects of an Fe-doped GaN buffer on OFF-state breakdown characteristics, HEMT devices with an Fe-doped GaN buffer on Si substrates were fabricated along with conventional devices utilizing an unintentionally doped GaN buffer on Si substrates. The device characteristics were compared. While HEMT devices with the conventional structure showed an extremely unstable OFF-state breakdown behavior due to punchthrough to the Si substrate, it was demonstrated that an Fe-doped GaN buffer layer on a Si substrate successfully suppressed the premature failure caused by Si-induced breakdown. As a result, the AlGaN/GaN HEMTs with an Fe-doped GaN buffer on Si substrates exhibited much more consistent and enhanced breakdown voltages, when compared with the conventional devices. Consequently, it is highly desirable that AlGaN/GaN HEMTs on Si substrates have an Fe-doped GaN buffer layer in order to achieve stable and robust OFF-state breakdown characteristics 相似文献
92.
大型火箭起飞横向漂移测量系统研究 总被引:1,自引:0,他引:1
本文论及了大型火箭发射起飞段横向漂移量的近距离高速摄影测量系统和数据处理方法。 相似文献
93.
94.
We apply the theory of signature invariants of links in rational homology spheres to covering links of homology boundary links. From patterns and Seifert matrices of homology boundary links, we derive an explicit formula to compute signature invariants of their covering links. Using the formula, we produce fused boundary links that are positive mutants of ribbon links but are not concordant to boundary links. We also show that for any finite collection of patterns, there are homology boundary links that are not concordant to any homology boundary links admitting a pattern in the collection.
95.
Spectroscopic Observation of the Hydroxy Position in Butanol Hydrates and Its Effect on Hydrate Stability 下载免费PDF全文
In this study, we investigate the crystal structures and phase equilibria of butanols+CH4+H2O systems to reveal the hydroxy group positioning and its effects on hydrate stability. Four clathrate hydrates formed by structural butanol isomers are identified with powder X‐ray diffraction (PXRD). In addition, Raman spectroscopy is used to analyze the guest distributions and inclusion behaviors of large alcohol molecules in these hydrate systems. The existence of a free OH indicates that guest molecules can be captured in the large cages of structure II hydrates without any hydrogen‐bonding interactions between the hydroxy group of the guests and the water‐host framework. However, Raman spectra of the binary (1‐butanol+CH4) hydrate do not show the free OH signal, indicating that there could be possible hydrogen‐bonding interactions between the guests and hosts. We also measure the four‐phase equilibrium conditions of the butanols+CH4+H2O systems. 相似文献
96.
Back Cover: Cofactor‐Free Light‐Driven Whole‐Cell Cytochrome P450 Catalysis (Angew. Chem. Int. Ed. 3/2015) 下载免费PDF全文
97.
Rücktitelbild: Cofactor‐Free Light‐Driven Whole‐Cell Cytochrome P450 Catalysis (Angew. Chem. 3/2015)
98.
99.
Nb2O5/C nanosheets are successfully prepared through a mixing process and followed by heating treatment.Such Nb2O5/C based electrode exhibits high rate performance and remarkable cycling ability, showing a high and stable specific capacity of ~380 mAh g-1 at the current density of 50 mA g-1(much higher than the theoretical capacity of Nb2O5).Further more,at a current density of 500 mA g-1,the nanocomposites electrode still exhibits a specific capacity of above 150 mAh g-1 after 100 cycles.These results suggest the Nb2O5/C nanocomposite is a high performance anode material for lithium-ion batteries. 相似文献
100.
This work studies the inverse problem of reconstructing an initial value function in the degenerate parabolic equation using the final measurement data. Problems of this type have important applications in the field of financial engineering. Being different from other inverse backward parabolic problems, the mathematical model in our article may be allowed to degenerate at some part of boundaries, which may lead to the corresponding boundary conditions missing. The conditional stability of the solution is obtained using the logarithmic convexity method. A finite difference scheme is constructed to solve the direct problem and the corresponding stability and convergence are proved. The Landweber iteration algorithm is applied to the inverse problem and some typical numerical experiments are also performed in the paper. The numerical results show that the proposed method is stable and the unknown initial value is recovered very well.© 2017 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 33: 1900–1923, 2017 相似文献