There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons--in particular their interaction with light--can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.

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Surface plasmon subwavelength optics

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Metamaterials provide resources for the development of unconventional optical devices and the improvement of conventional ones. We review the methods of analyzing, constructing and characterizing metamaterials, and discuss their extension to infrared and visible wavelengths.

Defining new optics with metamaterials

A modification of the synthetic-plane-wave-based holographic technique for determining radiation patterns and aperture fields of medium-gain horn antennas is proposed. The modification is based on using both the sum and difference of the near field and reference signals to form the hologram via simple low-cost amplitude-only near field measurements. This approach when compared to the previous version, where only the sum signal is used, allows increased sample spacing, and also provides an improvement in quality of the final results. The effectiveness of the modified technique is confirmed by both calculated and measured results obtained for some horn antennas at 10 GHz frequency.

A Modified Holographic Technique for Antenna Measurements

Microwave imaging systems have become increasingly prevalent owing to their ability to obtain 3D images while penetrating optically-opaque materials. These capabilities have motivated the development of various microwave imaging systems for applications ranging from security screening to biomedical imaging. Recent demonstrations have evidenced the idea that metasurface apertures can improve the hardware characteristics of microwave imaging systems due to their lightweight, low-cost, and planar nature. While metasurfaces can improve the antenna hardware, the large spectral bandwidth required for microwave imaging still incurs complex, costly, and performance-limiting RF components. To address the drawbacks inherent to using a large bandwidth, recent works have suggested that near-field microwave imaging can be performed at a single frequency point. In this work, monochromatic imaging is demonstrated by deploying two metasurface apertures to form a near-field microwave imaging system. By leveraging the unique radiation patterns emitted by metasurfaces, a pair of metasurface antennas, one acting as a transmitter and the other as a receiver, can acquire range and cross range information with measurements taken at a single frequency. We will show that this operation can then be supplemented by introducing aperture synthesis in the height direction to obtain fully 3D images. To account for the unusual illumination strategy, a reconstruction algorithm based on the range migration algorithm is formulated and implemented to enable efficient reconstruction of 3D images. Ultimately, the metasurface hardware, aperture synthesis, and monochromatic operation are combined to form an imaging system with high performance capabilities, without requiring complex and costly hardware.

Aperture synthesis with a monochromatic metasurface imaging system for 3D near-field imaging

This paper describes the modelling and analysis of a new smart antenna concept. The paper outlines the rational for the development of a dynamically reconfigurable smart antenna system without greatly increasing the complexity of the system. The subject smart antenna system is developed to offer good coverage and capacity using multiple beams throughout a cell sector and to be able to reconfigure the beam to provide enhanced coverage and maintain capacity in certain areas at reduced, but acceptable coverage throughout the rest of the cell sector of a mobile telecommunication network. The motivation behind the architecture and the methodology used is discussed and then modelling and analysis of the antenna system is presented.

Modelling and analysis of a smart antenna system with sub-sector dynamic capacity enhancement for mobile telecommunication networks

Raman microscopy is a valuable approach to label-free chemical imaging. Recent advances have enabled the development of rapid methods for hyperspectral microscopy using impulsive stimulated Raman scattering (ISRS) that focus on low-frequency Raman modes of materials. The persistent challenge with Raman spectroscopic methods is low signal due to the relatively weak Raman scattering. ISRS microscopy allows for high quality hyperspectral imaging of low and fingerprint Raman vibrational frequencies but is normally subject to poor performance in the presence of optical scattering. We will present methods that solve this issue and allow for high-quality imaging when strong optical scattering is present. 

David R. Smith

Papers

Defining new optics with metamaterials

A Modified Holographic Technique for Antenna Measurements

Aperture synthesis with a monochromatic metasurface imaging system for 3D near-field imaging

Modelling and analysis of a smart antenna system with sub-sector dynamic capacity enhancement for mobile telecommunication networks

Low frequency coherent Raman imaging with high optical scattering robustness (Conference Presentation)