Experiment of Doppler shift of diffraction beam

Optical heterodyne interfering is used to measure the Doppler shift of diffraction beam of moving plane grating. By introducing Doppler shift in reference beam and contrasting the final beat frequency, the Doppler shift is measured to be normal when incident light and diffraction light are in the same side of the normal of periodic plane grating, which shows that abnormal Doppler shift can not occur on the material with “negative refraction phenomenon” caused by periodicity. Periodic two-dimensional photonic crystal with the property of abnormal Doppler shift has equivalent negative refractive index, and the abnormal properties of left-handed materials are not only caused by periodicity.     

Sol-Gel Synthesis of Multi-Walled Carbon Nanotubes Reinforced Alumina-Silica Fibers

Multi-walled carbon nanotubes (MWCNTs) reinforced alumina-silica fibers were prepared by the sol-gel dry-spinning method. Aluminum isopropoxide (AIP), aluminum nitrite (AN), and tetraethyl orthosilicate (TEOS) were used as starting materials to prepare spinnable aluminosilicate sols in aqueous media. Polyvinylpyrrolidone (PVP) was used as dispersant agent to homogeneous disperses MWCNTs in the spinnable aluminosilicate sol through an in-situ process. The structure and mechanical properties of the MWCNTs reinforced alumina-silica fibers were studied. The results revealed that homogeneous dispersion of MWCNTs in alumina-silica fibers improved their mechanical properties considerably. The addition of only 0.5 wt% acid-treated MWCNTs into alumina-silica fibers result in a 60% increase in tensile strength to 398 ± 45 MPa.     

Dual‐Polymer‐Functionalized Nanoscale Graphene Oxide as a Highly Effective Gene Transfection Agent for Insect Cells with Cell‐Type‐Dependent Cellular Uptake Mechanisms

Efficient and safe gene transfection carriers, especially for hard‐to‐transfect cells, are urgently demanded in basic biological research and gene therapy applications. Many insect cell lines widely used in molecular cell biology exhibit relatively low transfection efficiencies when treated by conventional non‐viral agents. Herein, we develop a novel gene delivery vector by coating graphene oxide (GO) with both polyethylene glycol (PEG) and polyethylenimine (PEI), obtaining a dual‐polymer‐functionalized nanoscale GO (nGO‐PEG‐PEI) to transfect insect cells. While exhibiting remarkably reduced cytotoxicity compared with PEI, nGO‐PEG‐PEI, when used as the plasmid DNA transfection agent to treat Drosophila S2 cells, offers ≈7‐fold and ≈2.5‐fold higher efficiency compared with those achieved by using bare PEI and Lipofectamine 2000, a widely used commercial transfection agent, respectively. Interestingly, the advantages of nGO‐PEG‐PEI are even more dramatic when transfecting cells with lower‐quality linearized DNA. It is revealed that nGO‐PEG‐PEI/pDNA complexes enter insect cells via a unique pathway working even at a low temperature, rather different from their entry into mammalian adherent cells. Our results encourage the development of nano‐GO‐based gene carriers to treat special types of hard‐to‐transfect cells (e.g., insect cells), and indicate that nanomaterials would enter cells by cell‐type‐dependent mechanisms, which merit significantly more future attentions.     

Stem Cell Labeling and Tracking with Nanoparticles

Stem cell research is a field that has attracted tremendous attention in recent years. How to precisely label and track stem cells after administration is important not only for fundamental stem cell research, but also for practical applications of stem cell technology in the clinic. Various stem cell labeling and tracking strategies, many of which utilize nanotechnology, have been reported by many different groups. Here, recent progress in the development of various functional nanomaterials for stem cell labeling and tracking is reviewed and the current challenges and future prospects are discussed.     

应变Si NMOSFET漏电流解析模型

基于应变Si/SiGe器件结构,本文建立了统一的应变Si NMOSFET漏电流解析模型. 该模型采用平滑函数,实现了应变Si NMOSFET漏电流及其导数,从亚阈值区到强反型区以及从线性区到饱和区的平滑性,解决了模型的连续性问题. 同时考虑了载流子速度饱和效应和沟道长度调制效应的影响,进一步提高了模型精度. 通过将模型的仿真结果和实验结果对比分析,验证了所建模型的有效性. 该模型可为应变Si数字集成电路和模拟集成电路分析、设计提供重要参考. 关键词： 应变Si NMOSFET 漏电流 解析模型     

Information granulation and uncertainty measures in interval-valued intuitionistic fuzzy information systems

Information granulation and entropy are main approaches for investigating the uncertainty of information systems, which have been widely employed in many practical domains. In this paper, information granulation and uncertainty measures for interval-valued intuitionistic fuzzy binary granular structures are addressed. First, we propose the representation of interval-valued intuitionistic fuzzy information granules and examine some operations of interval-valued intuitionistic fuzzy granular structures. Second, the interval-valued intuitionistic fuzzy information granularity is introduced to depict the distinguishment ability of an interval-valued intuitionistic fuzzy granular structure (IIFGS), which is a natural extension of fuzzy information granularity. Third, we discuss how to scale the uncertainty of an IIFGS using the extended information entropy and the uncertainty among interval-valued intuitionistic fuzzy granular structures using the expanded mutual information derived from the presented intuitionistic fuzzy information entropy. Fourth, we discovery the relationship between the developed interval-valued intuitionistic fuzzy information entropy and the intuitionistic fuzzy information granularity presented in this paper.     

Concurrent binding and delivery of proteins and lipophilic small molecules using polymeric nanogels

Supramolecular nanoassemblies, which are capable of binding and delivering either lipophilic small molecules or hydrophilic molecules, are of great interest. Concurrently binding and delivering this combination of molecules is cumbersome, because of the opposing supramolecular host requirements. We describe the development of a versatile nanoassembly system that is capable of binding and delivering both, a protein and a lipophilic small molecule, simultaneously inside the cells.     

DNA microarray fabricated on poly(acrylic acid) brushes-coated porous silicon by in situ rolling circle amplification

Microarrays hold considerable promise in large-scale biology on account of their analytical, massive and parallel nature. In a step toward further enabling such a capability, we describe the application of rolling circle amplification (RCA) for a sensitive and multiplex detection of nucleic acid targets on oligonucleotide-conjugated polymer brushes covalently grown from porous silicon. Both RCA and polymer brushes have been taken to increase the loading quantity of target molecules and thus improve the detection sensitivity without loss of multiplexing. Besides, polymer brushes were employed to protect porous silicon and to provide biologically simulated environments, making the attached biomolecules maintain bioactivity. This approach can reach a detection limit of 0.1 nM target analytes and three orders of magnitude dynamic range of 0.1-100 nM, with a fluorescence scanner. A two-colour DNA microarray was achieved via RCA of two kinds of circular DNA targets on one chip simultaneously. The porous silicon chip-based RCA technique is promising for the multiplex detection of deoxynucleic acids on microarrays.     

Evidence of an oxidative-addition-promoted pd-leaching mechanism in the suzuki reaction by using a pd-nanostructure design

Nanocatalysts behave homogeneously: The structural changes of two rationally designed heterogeneous Pd-based nanocatalysts were examined in a Suzuki reaction. By taking advantage of additional nanostructural characteristics, direct evidence of the leaching of soluble Pd was obtained; hence, the catalysis is promoted by oxidative addition of aryl halides to the nanoparticles.     

Pd cluster nanowires as highly efficient catalysts for selective hydrogenation reactions

Palladium is a key catalyst invaluable to many industrial processes and fine-chemical synthesis. Although recent progress has allowed the synthesis of Pd nanoparticles with various shapes by using different techniques, the facile synthesis of Pd nanocrystals and turning them into a highly active, selective, and stable catalyst systems still remain challenging. Herein, we report the highly selective one-pot synthesis of monodisperse Pd cluster nanowires in aqueous solution; these consist of interconnected nanoparticles and may serve as highly active catalysts because of the enrichment of high index facets on the surface, including {443}, {331}, and {221} steps. For the first time, carbon nanotube and γ-Al(2)O(3) immobilized Pd cluster nanowires showed highly enhanced catalytic performance in the liquid-phase selective hydrogenation of cinnamaldehyde and gas-phase hydrogenation of 1,3butadiene relative to immobilized Pd icosahedra and nanocubes, as well as commercial Pd catalysts.