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911.
采用横向表面PiN(SPiN)二极管构造的硅基可重构天线具有众多优于传统天线的独特优势, 是实现天线小型化和提升雷达与微波通信系统性能的有效技术途径. 本文提出一种Si/Ge/Si异质横向SPiN二极管, 并基于双极扩散模型与Fletcher型边界条件, 在大注入条件下建立了二极管结电压、电流密度与本征区固态等离子体浓度分布解析模型, 并数值模拟分析了本征区长度、P+与N+区掺杂浓度、外加电压对所建模型的影响. 结果表明, 固态等离子体浓度随本征区长度的增加下降, 随外加电压的增加而指数上升, 随P+与N+区掺杂浓度的提高而上升, 电流密度随外加电压的增加而指数上升. 同等条件下, 异质SPiN二极管的固态等离子体浓度相比同质二极管提高近7倍以上. 本文所建模型为硅基可重构天线的设计与应用提供有效的参考. 相似文献
912.
913.
914.
Jong Eel Park Kyeong Wan Woo Sang Un Choi Je Hyun Lee Kang Ro Lee 《Helvetica chimica acta》2014,97(1):56-63
Two new spirostane‐steroidal saponins, bletilnoside A ( 1 ) and bletilnoside B ( 2 ), together with five known compounds, 3 – 7 , were isolated from the roots of Bletilla striata (Thunb .) Reichb . F. The structures of the new compounds were determined based on their 1D‐ and 2D‐NMR spectral data. The isolated compounds 1 – 7 were tested for cytotoxicity against four human tumor cells (A549, SK‐OV‐3, SK‐MEL‐2, and HCT15) in vitro using a sulforhodamin B bioassay, and compounds 1, 2 , and 5 showed significant cytotoxicities against all tested tumor cell lines with IC50 values ranging from 3.98±0.16 to 12.10±0.40 μM . 相似文献
915.
Tian‐hao Huang Ying‐hui Wang Zhi‐hui Kang Jin‐bo Yao Ran Lu Han‐zhuang Zhang 《Photochemistry and photobiology》2014,90(1):29-34
The effects of π‐spacer and electron donor groups on the photophysical behaviors of fluorenone‐based linear conjugated oligomers have been systemically investigated. Solvent‐dependent steady‐state measurements exhibit that the fluorene vinylene (FV) spacer and the electron‐donating ability of donor group are able to modulate the spectral features of oligomers and the fluorescence quantum yield could decrease with the increasing of the solvent polarity. Meanwhile, quantum chemical calculation simulates their absorption spectra, and analyzes their electron transition components simultaneously. The transient absorption measurements focus on the photoexcitation dynamics of these oligomers in the toluene solution, which show that an intramolecular charge transfer state exists in the relaxation process of excited states, and its generation process could accelerate with the introduction of FV spacer and the enhancement of donor strength. 相似文献
916.
Ying‐Hui Wang Lu Zou Zhi‐Hui Kang Cheng Qian Fuyin Wang Yu‐Guang Ma Ran Lu Hong Ji Han‐Zhuang Zhang 《Photochemistry and photobiology》2014,90(1):45-50
We study the photophysical characters of two oligofluorenes‐functionalized anthracenes molecules with different fluorine‐vinylene (FV) units, which exhibits that “excimer” state appears in the solution after photoexcitation. The dynamic data shows that two mechanisms are responsible for the generation of “excimer”. The fast one is controlled by the arene‐arene interaction between molecules and the slow one is influenced by the diffusion motion of molecules. Increasing the number of FV units may suppress the DM‐dependent “excimer” and enhance the yield of intrinsic fluorescence, which finally improves the fluorescence property of molecules in solution. 相似文献
917.
Stereoselective redox cyanation of alkynyl aldehydes was explored, furnishing (E)-α,β-unsaturated acyl cyanides. This reaction was catalyzed by mild TEA base, as a dual role of Lewis base and Brönsted base. TMSCN treated with TEA was an effective reagent for generating umpolung intermediates from alkynyl aldehydes, and this nucleophilic intermediate can be protonated by equimolar amount of EtOH, promoting the efficient conversion into α,β-unsaturated acyl cyanides. The synthesized acyl cyanides were successfully applied as the synthetic precursors in the iron-catalyzed arylation reactions. 相似文献
918.
Mi-Seon Jeong Yongsoo Hwang Chul-Hyung Kang 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):287-293
A deep geologic disposal is the prime option for the long-term isolation of high-level radioactive waste (HLW) in many countries.
For deeply located repositories, a radionuclide released from a failed waste container moves through the engineered and natural
barriers before it reaches a biosphere. The pseudo-colloid which a radionuclide is adsorbed on a moving natural humic or fulvic
colloid can be generated in a fractured porous medium. The size of a colloid is in general in the order of a hundred nanometer
so that its migration velocity in a fracture is higher than that of a radionuclide due to the hydrochromatic effect. A large
colloid cannot diffuse easily into a surrounding rock. Also, there are many kinds of actinides and these actinides have decay
chains. In this analysis, the canonical form solution is derived for a pseudo-colloid and a solute in a fracture and a surrounding
rock with a realistic inlet boundary condition with multi-member decay chains. It is used the Fortran based a computational
code which uses a special subroutine for the inversion of Laplace transform. Consequently, the role of the pseudo-colloid
in the fractured porous medium is important and also their decay chains aren’t neglected in the performance assessment of
the HLW. 相似文献
919.
Wen Wang Ruigang Liu Hongliang Kang Weili Liu Wenyong Liu Yong Huang 《Colloid and polymer science》2011,289(4):371-379
The photo-polymerization-induced banded texture of ethyl-cyanoethyl cellulose/acrylic acid/copper acrylate ((E-CE)C/AA/CuAA2) cholesteric liquid crystalline (CLC) solutions were investigated. The results indicate that the CLC phase can be fixed by
the photo-polymerization. Banded texture was obtained in the photo-polymerized CLC films. The orientation of the banded texture
induced by the photo-polymerization depends on the gradient of UV irradiations on the surface of the (E-CE)C/AA/CuAA2 CLC solutions. CLC films with different patterns can be obtained by introducing the UV irradiation gradient on the (E-CE)C/AA/CuAA2 CLC solutions surface by using masks with different patterns. The simple approach for the fabrication of CLC films with different
patterns may have the potential application in the fields of holographic image storage. 相似文献
920.
Gold nanoparticles possess a unique combination of properties which allow them to act as highly multifunctional anti-cancer agents (X. H. Huang, P. K. Jain, I. H. El-Sayed and M. A. El-Sayed, Nanomedicine, 2007, 2, 681-693; P. Ghosh, G. Han, M. De, C. K. Kim and V. M. Rotello, Adv. Drug Delivery Rev., 2008, 60, 1307-1315; S. Lal, S. E. Clare and N. J. Halas, Acc. Chem. Res., 2008, 41, 1842-1851; D. A. Giljohann, D. S. Seferos, W. L. Daniel, M. D. Massich, P. C. Patel and C. A. Mirkin, Angew. Chem., Int. Ed., 2010, 49, 3280-3294). Not only can they be used as targeted contrast agents for photothermal cancer therapy, they can serve as scaffolds for increasingly potent cancer drug delivery, as transfection agents for selective gene therapy, and as intrinsic antineoplastic agents. This tutorial review will highlight some of the many forms and recent applications of these gold nanoparticle conjugates by our lab and others, as well as their rational design and physiologic interactions. 相似文献