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.

/pdf/surface-plasmon-subwavelength-optics-5e55p12p4o.pdf

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

Indirect microwave holographic techniques offer a simple, low cost technique for a range of microwave measurements including the determination of antenna characteristics and the ability to provide good quality images of passive objects. This work provides a brief outline of the basic theory of indirect microwave holography and how it can be used for the reconstruction of scattered complex fields at the measurement plane and how these results can be back propagated to provide the scattered fields at any preselected observation plane. It provides an outline of the different techniques required for antenna measurement and the imaging of passive objects. It demonstrates how indirect holography can be used to determine the far field radiation pattern of a high gain antenna and reconstruct the complex antenna aperture fields. This work also demonstrates the use of indirect holography for the imaging of passive objects. The techniques described have been validated by experimental results on a range of objects including buried objects.

An outline of indirect holographic methods for antenna measurements and microwave imaging

We present the design and experimental demonstration of an efficient holographic metasurface aperture that focuses microwaves in the Fresnel zone. The proposed circular structure consists of two stacked plates with their periphery terminated in a conductive layer. Microwaves are injected into the bottom plate, which forms the feed layer, and are coupled to the top holographic metasurface layer via an annular ring. This coupling results in an inward traveling cylindrical wave in the top layer, which serves as the reference wave for a hologram. The radiating elements consist of a slot pair with their orientations designed to couple efficiently with the cylindrical reference wave while maintaining a linearly polarized focused beam. A general condition on the slot pairs radiated power is proposed to ensure low sidelobe level (SLL) and is validated with full-wave simulation. An aperture that is 20 cm in diameter, operates at 20 GHz in the K-band frequency, and forms a diffraction-limited focal spot at a distance of 10 cm is experimentally demonstrated. The proposed near-field focusing metasurface has high antenna efficiency and can find application as a compact source for Fresnel-zone wireless power transfer and remote sensing schemes.

https://www.mdpi.com/2079-9292/10/15/1837/pdf

Efficient Holographic Focusing Metasurface

THz radiation transmission through a dual-band electric metamaterial is presented, where we analyze manufacturing defects in the metamaterial Removing different resonator percentages allows us to quantify the effects of manufacturing defects on the material response

/pdf/dual-band-planar-electric-thz-metamaterial-with-resonator-4ilj8eeh3g.pdf

Dual-band planar electric thz metamaterial with resonator yield analysis

The use of indirect holographic techniques for antenna testing has been shown to offer a simple, low cost scalar technique for the reconstruction of complex antenna aperture fields. This work extends the use of indirect holography to the imaging of objects. This work provides a brief outline of the basic theory of indirect microwave holography and how it can be used for the reconstruction of scattered complex fields at the measurement plane and how these results can be back propagated to provide images of the scattered fields at the position of the original object. The techniques described have been validated by experimental results on a range of objects including buried objects.

The use of indirect holographic techniques for microwave imaging

An automatically adjustable radiofrequency link system includes a radiofrequency transmitter configured to transmit a signal at a frequency of transmission within an extremely high frequency (EHF) band. The system further includes a receiving device configured to receive the transmitted signal and provide feedback to a processing circuit communicatively coupled to the transmitter and the receiving device, wherein the feedback is related to the received signal. The processing circuit is configured to determine required signal properties based on the feedback and determine signal loss properties including an effect of atmospheric absorption, as a function of frequency; determine a modification to the transmitted signal using the signal loss properties and the required signal properties; and adjust the frequency of transmission to obtain a desired transmission signal using the modification.

David R. Smith

Papers

An outline of indirect holographic methods for antenna measurements and microwave imaging

Efficient Holographic Focusing Metasurface

Dual-band planar electric thz metamaterial with resonator yield analysis

The use of indirect holographic techniques for microwave imaging

Automatically adjustable radiofrequency link