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901.
Drug Delivery: Thiolation and Cell‐Penetrating Peptide Surface Functionalization of Porous Silicon Nanoparticles for Oral Delivery of Insulin (Adv. Funct. Mater. 20/2016) 下载免费PDF全文
902.
通过对化学腐蚀法制备的单晶硅表面微结构进行分析,建立了一种金字塔微结构的数学模型,采用时域有限差分法(FDTD)数值计算了波长在300~1 000 nm范围内微结构表面反射率随波长的变化规律,并将计算结果与实验测量结果进行了比较、分析和解释.在此基础上,针对不同实验条件下所形成的金字塔微结构差异,数值计算了几种不同参数金字塔结构表面的反射率随波长的变化规律.研究表明,反射率随金字塔的占空比和倾角的增大而减小,而金字塔尺寸变化对反射率的影响较小.当金字塔的结构参数为底边长2 μm、占空比1、倾角约60°时减反效果较好,平均反射率仅为6.28%. 相似文献
903.
904.
Claudio Ferraro Esther Garcia‐Tuñon Victoria G. Rocha Suelen Barg Maria Dolores Fariñas Tomas E. Gomez Alvarez‐Arenas Giorgio Sernicola Finn Giuliani Eduardo Saiz 《Advanced functional materials》2016,26(10):1636-1645
The directional freezing of microfiber suspensions is used to assemble highly porous (porosities ranging between 92% and 98%) SiC networks. These networks exhibit a unique hierarchical architecture in which thin layers with honeycomb‐like structure and internal strut length in the order of 1–10 μm in size are aligned with an interlayer spacing ranging between 15 and 50 μm. The resulting structures exhibit strengths (up to 3 MPa) and stiffness (up to 0.3 GPa) that are higher than aerogels of similar density and comparable to other ceramic microlattices fabricated by vapor deposition. Furthermore, this wet processing technique allows the fabrication of large‐size samples that are stable at high temperature, with acoustic impedance that can be manipulated over one order of magnitude (0.03–0.3 MRayl), electrically conductive and with very low thermal conductivity. The approach can be extended to other ceramic materials and opens new opportunities for the fabrication of ultralight structures with unique mechanical and functional properties in practical dimensions. 相似文献
905.
Modulation of the intensity of light by high quality reflective micro-displays is predominantly carried out by liquid crystal over silicon (LCoS) spatial light modulator (SLM) technology for applications such as pico-projectors. Wider use of these devices, in applications such as computer-generated holography and optical correlation, is limited by their phase modulation ability and illumination polarisation state dependence. These devices rely on planar or twisted nematic liquid crystals to modulate the light, but due to their viscoelastic properties they are inherently slow. Research into the use of the polymer stabilised blue phase has already shown that it can offer high speed phase modulation. However, other chiral nematic orientations are yet to be compared in LCoS devices. In this article, we demonstrate that polymer-stabilised chiral nematic liquid crystal electro-optical effects can offer phase modulation in silicon backplane devices. The uniform standing helix and focal conic textures are shown to be independent of the input light polarisation state and the uniform lying helix is shown to be polarisation dependent. These optical responses are then compared with that of the blue phase to identify a suitable orientation for further development in LCoS technology in order to find a high-speed, full phase modulating material. 相似文献
906.
Ab initio potential energy surface and vibration‐rotation energy levels of silicon dicarbide,SiC2 下载免费PDF全文
Jacek Koput 《Journal of computational chemistry》2016,37(26):2395-2402
The accurate ground‐state potential energy surface of silicon dicarbide, SiC2, has been determined from ab initio calculations using the coupled‐cluster approach. Results obtained with the conventional and explicitly correlated coupled‐cluster methods were compared. The core‐electron correlation, higher‐order valence‐electron correlation, and scalar relativistic effects were taken into account. The potential energy barrier to the linear SiCC configuration was predicted to be 1782 cm?1. The vibration‐rotation energy levels of the SiC2, 29SiC2, 30SiC2, and SiC13C isotopologues were calculated using a variational method. The experimental vibration‐rotation energy levels of the main isotopologue were reproduced to high accuracy. In particular, the experimental energy levels of the highly anharmonic vibrational ν3 mode of SiC2 were reproduced to within 6.7 cm?1, up to as high as the v3 = 16 state. 相似文献
907.
Analysis of the bond‐valence method for calculating 29Si and 31P magnetic shielding in covalent network solids 下载免费PDF全文
Sean T. Holmes Fahri Alkan Robbie J. Iuliucci Karl T. Mueller Cecil Dybowski 《Journal of computational chemistry》2016,37(18):1704-1710
29Si and 31P magnetic‐shielding tensors in covalent network solids have been evaluated using periodic and cluster‐based calculations. The cluster‐based computational methodology employs pseudoatoms to reduce the net charge (resulting from missing co‐ordination on the terminal atoms) through valence modification of terminal atoms using bond‐valence theory (VMTA/BV). The magnetic‐shielding tensors computed with the VMTA/BV method are compared to magnetic‐shielding tensors determined with the periodic GIPAW approach. The cluster‐based all‐electron calculations agree with experiment better than the GIPAW calculations, particularly for predicting absolute magnetic shielding and for predicting chemical shifts. The performance of the DFT functionals CA‐PZ, PW91, PBE, rPBE, PBEsol, WC, and PBE0 are assessed for the prediction of 29Si and 31P magnetic‐shielding constants. Calculations using the hybrid functional PBE0, in combination with the VMTA/BV approach, result in excellent agreement with experiment. © 2016 Wiley Periodicals, Inc. 相似文献
908.
Ulaş Sabahattin Gökay Muhammad Zakwan Abdullah Demir Ali Serpengüzel 《Fiber and Integrated Optics》2016,35(1):38-46
In this article, Fano lineshape whispering gallery modes were observed in the light scattering spectrum of a silicon microsphere in near-infrared telecommunication wavelengths. A simple model is presented to explain the transition from Lorentzian lineshape to the Fano lineshape resonances with the coupled-mode theory of multiple whispering gallery modes. Polar mode spacing of 0.23 nm is observed in the spectra, which correlates well with the calculated value. The quality factor of the Lorentzian and Fano resonances are on the order of 105. By using an appropriate interface design for the microsphere coupling geometries, Fano lineshape optical resonances herald novel device applications for silicon volumetric lightwave circuits. 相似文献
909.
ABSTRACTThis study investigates the optical resonance spectra of free-standing monolithic single crystal silicon microspheres immersed in various amorphous fluids, such as air, water, ethylene glycol, and 4-Cyano-4’-pentylbiphenyl nematic liquid crystal. For the various amorphous fluids, morphology-dependent resonances with quality factors on the order of 105 are observed at 1428 nm. The mode spacing is always on the order of 0.23 nm. The immersion in various amorphous fluids affects the spectral response of the silicon microsphere and heralds this technique for use in novel optofluidics applications. Even though the nematic liquid crystal is a highly birefringent, scattering, and high-index optical medium, morphology-dependent resonances with quality factors on the order of 105 are observed at 1300 nm in the elastic scattering spectra of the silicon microsphere, realizing a liquid-crystal-on-silicon geometry. The relative refractive index and the size parameter of the silicon microsphere are the parameters that affect the resonance structure. The more 4-Cyano-4’-pentylbiphenyl interacting with the silicon microsphere, the lower the quality factor of the resonances is. The more 4-Cyano-4’-pentylbiphenyl is interacting with the silicon microsphere, the lower the mode spacing Δλ of the resonances is. The silicon microspheres wetted with nematic liquid crystal can be used for optically addressed liquid-crystal-on-silicon displays, light valve applications, or reconfigurable optical networks. 相似文献
910.
Dr. Kazunobu Igawa Daisuke Yoshihiro Yusuke Abe Prof. Dr. Katsuhiko Tomooka 《Angewandte Chemie (International ed. in English)》2016,55(19):5814-5818
A variety of functionalized silacyclopentanes were synthesized by highly enantioselective β‐eliminations of silacyclopentene oxides followed by stereospecific transformations. The reaction mechanism of the β‐elimination was elucidated by DFT calculations. An in vitro biological assay with an oxy‐functionalized silacyclopentane showed substantial binding to a serotonin receptor protein. 相似文献